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Sample records for catalyzes coumarin 7-hydroxylation

  1. Coumarin embryopathy

    Energy Technology Data Exchange (ETDEWEB)

    Struwe, F.E.; Reinwein, H.; Stier, R.

    1984-02-01

    Anticoagulant therapy using Coumarin derivatives (vitamin K antagonists) during early pregnancy may result in a characteristic embryopathy appearing as a phaenocopy of chondrodysplasia punctata (Conradi-Huenermann's disease). This has been suggested in advance by observations made in newborns of mothers who had been treated previously with Warfarin or Acenocoumon. Similar observations made in a newborn after the mother's treatment with Phencoumon in early pregnancy are described in this paper. Coumarin embryopathy is proposed as a common term.

  2. Tandem aldehyde–alkyne–amine coupling/cycloisomerization: A new synthesis of coumarins

    Directory of Open Access Journals (Sweden)

    Maddi Sridhar Reddy

    2013-01-01

    Full Text Available Cu-catalyzed A3 coupling of ethoxyacetylene, pyrrolidine and salicylaldehydes led to a concomitant cycloisomerization followed by hydrolysis of the resultant vinyl ether to afford coumarins in a cascade process. The reaction proceeded through exclusive 6-endo-dig cyclization and is compatible with halo and keto groups giving coumarins in good to moderate yields.

  3. Coumarins from Edgeworthia chrysantha.

    Science.gov (United States)

    Li, Xing-Nuo; Tong, Sheng-Qiang; Cheng, Dong-Ping; Li, Qing-Yong; Yan, Ji-Zhong

    2014-02-13

    A new coumarin, edgeworic acid (1), was isolated from the flower buds of Edgeworthia chrysantha, together with the five known coumarins umbelliferone (2), 5,7-dimethoxycoumarin (3), daphnoretin (4), edgeworoside C (5), and edgeworoside A (6). Their structures were established on the basis of spectral data, particularly by the use of 1D NMR and several 2D shift-correlated NMR pulse sequences (1H-1H COSY, HSQC and HMBC), in combination with acetylation reactions.

  4. Microwave Assisted Convenient One-Pot Synthesis of Coumarin Derivatives via Pechmann Condensation Catalyzed by FeF3 under Solvent-Free Conditions and Antimicrobial Activities of the Products

    Directory of Open Access Journals (Sweden)

    Vahid Vahabi

    2014-08-01

    Full Text Available A rapid and efficient solvent-free one-pot synthesis of coumarin derivatives by Pechmann condensation reactions of phenols with ethyl acetoacetate using FeF3 as a catalyst under microwave irradiation is described. This one-pot synthesis on a solid inorganic support provides the products in good yields. The newly synthesized compounds were systematically characterized by IR, 1H-NMR, 13C-NMR, MS and elemental CHN analyses. The proposed solvent-free microwave irradiation method using the environmentally friendly catalyst FeF3 offers the unique advantages of high yields, shorter reaction times, easy and quick isolation of the products, excellent chemoselectivity, and a one-pot, green synthesis. The products were screened for antimicrobial activity, and the results showed that the compounds reacted against all the tested bacteria.

  5. Sesquiterpene coumarins from Ferula gumosa.

    Science.gov (United States)

    Iranshahi, Mehrdad; Masullo, Milena; Asili, Ali; Hamedzadeh, Ali; Jahanbin, Bentolhoda; Festa, Michela; Capasso, Anna; Piacente, Sonia

    2010-11-29

    A new sesquiterpene coumarin, gumosin (1), two new sesquiterpene coumarin glycosides, gumosides A (2) and B (3), and 10 known compounds, namely, cauferoside (4), feselol (5), conferoside, ferilin, ferocaulidin, ligupersin A, conferol, and daucosterol, and the phenolic compounds acantrifoside E and 4-hydroxybenzoic acid 4-(6-O-sulfo)glucopyranoside, were isolated from a methanolic extract of Ferula gumosa roots. The structures of 1-3 were elucidated by spectroscopic data interpretation. The cytotoxic activity of the sesquiterpene coumarin derivatives was evaluated against a small panel of cancer cell lines.

  6. Growth until puberty after in utero exposure to coumarins

    NARCIS (Netherlands)

    Van Driel, D; Wesseling, J; Rosendaal, FR; Odink, RJ; Van der Veer, E; Gerver, WJ; Geven-Boere, LM; Sauer, PJJ

    2000-01-01

    Anticoagulation with coumarins is an effective therapy during pregnancy. Fetal exposure to coumarin derivatives during the first trimester, however, is associated with skeletal anomalies (warfarin or coumarin embryopathy). Information about long-term effects of prenatal coumarin exposure on the

  7. Cyclization of ortho-hydroxycinnamates to coumarins under mild conditions: A nucleophilic organocatalysis approach

    Directory of Open Access Journals (Sweden)

    Florian Boeck

    2012-09-01

    Full Text Available (E-Alkyl ortho-hydroxycinnamates cyclize to coumarins at elevated temperatures of 140–250 °C. We find that the use of tri-n-butylphosphane (20 mol % as a nucleophilic organocatalyst in MeOH solution allows cyclization to take place under much milder conditions (60–70 °C. Several coumarins were prepared, starting from ortho-hydroxyarylaldehydes, by Wittig reaction with Ph3P=CHCO2Me to (E-methyl ortho-hydroxycinnamates, followed by the phosphane catalyzed cyclization.

  8. Evaluation of Halogenated Coumarins for Antimosquito Properties

    Directory of Open Access Journals (Sweden)

    Venugopala K. Narayanaswamy

    2014-01-01

    Full Text Available Mosquitoes are the major vectors of parasites and pathogens affecting humans and domestic animals. The widespread development of insecticide resistance and negative environmental effects of most synthetic compounds support an interest in finding and developing alternative products against mosquitoes. Natural coumarins and synthetic coumarin analogues are known for their several pharmacological properties, including being insecticidal. In the present study halogenated coumarins (3-mono/dibromo acetyl, 6-halogenated coumarin analogues were screened for larvicidal, adulticidal, and repellent properties against Anopheles arabiensis, a zoophilic mosquito that is one of the dominant vectors of malaria in Africa. Five compounds exerted 100% larval mortality within 24 h of exposure. All coumarins and halogenated coumarins reversibly knocked down adult mosquitoes but did not kill them after 24 h of exposure. Repellent properties could not be evidenced. Five compounds were considered potential larvicidal agents for further research and development, while adulticidal activity was considered only mild to moderate.

  9. Coumarin-fused coumarin: antioxidant story from N,N-dimethylamino and hydroxyl groups.

    Science.gov (United States)

    Xi, Gao-Lei; Liu, Zai-Qun

    2015-04-08

    Two coumarin skeletons can form chromeno[3,4-c]chromene-6,7-dione by sharing with the C ═ C in lactone. The aim of the present work was to explore the antioxidant effectiveness of the coumarin-fused coumarin via six synthetic compounds containing hydroxyl and N,N-dimethylamino as the functional groups. The abilities to quench 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) cationic radical (ABTS(+•)), 2,2'-diphenyl-1-picrylhydrazyl radical (DPPH), and galvinoxyl radical revealed that the rate constant for scavenging radicals was related to the amount of hydroxyl group in the scaffold of coumarin-fused coumarin. But coumarin-fused coumarin was able to inhibit DNA oxidations caused by (•)OH, Cu(2+)/glutathione (GSH), and 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH) even in the absence of hydroxyl group. In particular, a hydroxyl and an N,N-dimethylamino group locating at different benzene rings increased the inhibitory effect of coumarin-fused coumarin on AAPH-induced oxidation of DNA about 3 times higher than a single hydroxyl group, whereas N,N-dimethylamino-substituted coumarin-fused coumarin possessed high activity toward (•)OH-induced oxidation of DNA without the hydroxyl group contained. Therefore, the hydroxyl group together with N,N-dimethylamino group may be a novel combination for the design of coumarin-fused heterocyclic antioxidants.

  10. Photodimerisation of a coumarin-dipeptide gelator.

    Science.gov (United States)

    Draper, Emily R; McDonald, Tom O; Adams, Dave J

    2015-08-18

    Here we report a coumarin based hydrogelator that can form bulk gels, or homogeneous thin gels via an electrochemical pH drop. The gel can then be strengthened by post-gelation photodimerisation of the coumarin groups by irradiating with UV light.

  11. Convergent Synthesis of Two Fluorescent Ebselen-Coumarin Heterodimers

    Directory of Open Access Journals (Sweden)

    Jim Küppers

    2016-07-01

    Full Text Available The organo-seleniumdrug ebselen exhibits a wide range of pharmacological effects that are predominantly due to its interference with redox systems catalyzed by seleno enzymes, e.g., glutathione peroxidase and thioredoxin reductase. Moreover, ebselen can covalently interact with thiol groups of several enzymes. According to its pleiotropic mode of action, ebselen has been investigated in clinical trials for the prevention and treatment of different ailments. Fluorescence-labeled probes containing ebselen are expected to be suitable for further biological and medicinal studies. We therefore designed and synthesized two coumarin-tagged activity-based probes bearing the ebselen warhead. The heterodimers differ by the nature of the spacer structure, for which—in the second compound—a PEG/two-amide spacer was introduced. The interaction of this probe and of ebselen with two cysteine proteases was investigated.

  12. Cytotoxic coumarins from Toddalia asiatica.

    Science.gov (United States)

    Phatchana, Ratchanee; Yenjai, Chavi

    2014-06-01

    Three new coumarins and 13 known compounds were isolated from the stem bark of Toddalia asiatica. Compounds 1, 3, 8, and 9 showed cytotoxicity against the NCI-H187 cell line with IC50 values ranging from 6 to 9 µg/mL. Compounds 4 and 9 exhibited cytotoxicity against the MCF-7 cell line with IC50 values of 3.17 and 9.79 µg/mL, respectively. Compound 9 also displayed cytotoxic activity against KB cells with an IC50 value of 8.63 µg/mL. In addition, compound 14 showed antimalarial activity against Plasmodium falciparum with an IC50 value of 3.66 µg/mL. Compounds 5, 9, and 16 exhibited antituberculosis activity against Mycobacterium tuberculosis with MIC values of 50, 50, and 25 µg/mL, respectively. Georg Thieme Verlag KG Stuttgart · New York.

  13. Biologically active sesquiterpene coumarins from Ferula species.

    Science.gov (United States)

    Nazari, Zeinab Esmail; Iranshahi, Mehrdad

    2011-03-01

    Extracts from different species of the genus Ferula (Apiaceae) have had various biomedical applications for many centuries. Many biological features of this genus such as cytotoxicity, antibacterial, antiviral, P-glycoprotein (P-gp) inhibitory and antiinflammatory activity have been attributed to sesquiterpene coumarins; structures containing a common coumarin group and a sesquiterpene moiety. This both highlights the importance of sesquiterpene coumarins as biologically active natural products and necessitates further studies on these compounds. Taking into account the versatile biological properties of compounds isolated from Ferula and the unprecedented interest in the application of natural products as a new generation of therapeutics, the present review will discuss reports on biological activities of sesquiterpene coumarins of the genus Ferula, from 1990 onwards. Copyright © 2010 John Wiley & Sons, Ltd.

  14. Coumarins from roots of Clausena excavata.

    Science.gov (United States)

    Peng, Wen-Wen; Zheng, Yu-Qing; Chen, Yi-Shan; Zhao, Si-Meng; Ji, Chang-Jiu; Tan, Ning-Hua

    2013-01-01

    Two new coumarins, clauexcavatins A (1) and B (2), along with seven known ones (3-9), were isolated from the roots of Clausena excavata Burm. f. (Rutaceae). Their structures were elucidated on the basis of spectral data.

  15. Compound list: coumarin [Open TG-GATEs

    Lifescience Database Archive (English)

    Full Text Available coumarin CMA 00027 ftp://ftp.biosciencedbc.jp/archive/open-tggates/LATEST/Human/in_vitro/coum...arin.Human.in_vitro.Liver.zip ftp://ftp.biosciencedbc.jp/archive/open-tggates/LATEST/Rat/in_vitro/coum...arin.Rat.in_vitro.Liver.zip ftp://ftp.biosciencedbc.jp/archive/open-tggates/LATEST/Rat/in_vivo/Liver/Single/coum...-tggates/LATEST/Rat/in_vivo/Liver/Repeat/coumarin.Rat.in_vivo.Liver.Repeat.zip ...

  16. Halogenated coumarin derivatives as novel seed protectants.

    Science.gov (United States)

    Brooker, N; Windorski, J; Bluml, E

    2008-01-01

    Development of new and improved antifungal compounds that are target-specific is backed by a strong Federal, public and commercial mandate. Many plant-derived chemicals have proven fungicidal properties, including the coumarins (1,2-Benzopyrone) found in a variety of plants such as clover, sweet woodruff and grasses. Preliminary research has shown the coumarins to be a highly active group of molecules with a wide range of antimicrobial activity against both fungi and bacteria. It is believed that these cyclic compounds behave as natural pesticidal defence molecules for plants and they represent a starting point for the exploration of new derivative compounds possessing a range of improved antifungal activity. Within this study, derivatives of coumarin that were modified with halogenated side groups were screened for their antifungal activity against a range of soil-borne plant pathogenic fungi. Fungi included in this in vitro screen included Macrophomina phaseolina (charcoal rot), Phytophthora spp. (damping off and seedling rot), Rhizoctonia spp. (damping off and root rot) and Pythium spp. (seedling blight), four phylogenetically diverse and economically important plant pathogens. Studies indicate that these halogenated coumarin derivatives work very effectively in vitro to inhibit fungal growth and some coumarin derivatives have higher antifungal activity and stability as compared to the original coumarin compound alone. The highly active coumarin derivatives are brominated, iodinated and chlorinated compounds and results suggest that besides being highly active, very small amounts can be used to achieve LD100 rates. In addition to the in vitro fungal inhibition assays, results of polymer seed coating compatibility and phytotoxicity testing using these compounds as seed treatments will also be reported. These results support additional research in this area of natural pesticide development.

  17. Evolutionary tendency of coumarin-bearing families in angiospermae

    OpenAIRE

    Ribeiro, Claudia Valeria Campos; Kaplan, Maria Auxiliadora Coelho

    2002-01-01

    Coumarins are special metabolites well distributed in the Angiospermae, either in Monocotyledoneae or Dicotyledoneae. Simple coumarins, the most widespread type, is found in all coumarin-producing families, such as: Apiaceae, Rutaceae, Asteraceae, Fabaceae, Oleaceae, Moraceae e Thymelaeaceae. The other types, linear- and angular furanocoumarins, linear- and angular pyranocoumarins, lignocoumarins, bis- and triscoumarins, are of more restricted circumscription. Among the families with occurren...

  18. GAS PHASE ION CHEMISTRY OF COUMARINS: AB INITIO ...

    African Journals Online (AJOL)

    B. S. Chandravanshi

    Initio calculations favoured ionization by resonance electron capture for acetyl coumarin derivatives and dissociative electron capture by methyl substituted coumarins. Those coumarins that underwent resonance electron capture showed much higher intensities of M˙¯ than [M– H]¯ ions. These observations will be useful in ...

  19. New coumarin derivatives as carbonic anhydrase inhibitors.

    Science.gov (United States)

    Karataş, Mert Olgun; Alici, Bülent; Cakir, Umit; Cetinkaya, Engin; Demir, Dudu; Ergün, Adem; Gençer, Nahit; Arslan, Oktay

    2014-06-01

    In the current study, a series of 4-chloromethyl-7-hydroxy-coumarin derivatives containing imidazolium, benzimidazolium, bisbenzimidazolium and quaternary ammonium salts were synthesized, characterized and the inhibition effects of the derivatives on human carbonic anhydrases (hCA I and hCA II) were investigated as in vitro. Structures of these coumarins were confirmed by FT-IR, (1)H NMR, (13)C NMR and LC-MS analyses. Structure activity relationship study showed that 3d (IC50: 79 μM for hCA I and 88 μM for hCA II) performed higher inhibitory activity than others.

  20. Liver damage induced by coumarin anticoagulants.

    Science.gov (United States)

    Ehrenforth, S; Schenk, J F; Scharrer, I

    1999-01-01

    Except for bleeding complications, relevant adverse effects of coumarin anticoagulants are comparatively rare considering the widespread use of these substances. Here we present the case of a 56-year-old woman who developed recurrent episodes of severe hepatitis following repeated exposure to phenprocoumon (Marcumar; Roche, Grenzach-Wyhlen, Germany) and warfarin (Coumadin; DuPont Pharma, Bad Homburg, Germany) after replacement of the mitral valve with a mechanical prosthesis. The diagnosis of "coumarin-induced hepatitis" is compatible with the time relationship between start of the drug and the onset of hepatopathy (first episode 8 months, second episode 4 weeks, and third episode 7 days), the rapid improvement following discontinuation of the drug, recurrence of liver dysfunction after re-exposure to the drug, and liver histology. After anticoagulant therapy was changed to heparin and acenocoumarol (Sintrom; Ciba-Geigy, Basel, Switzerland), the patient's general state was markedly improved and her liver values became almost normal. This case will be discussed and compared with other reports of coumarin-induced hepatic lesions. Although liver damage induced by coumarin derivates is rare, it is important to be aware of the hepatotoxic potential of these drugs, which, in most cases, mimics the clinical presentation of viral hepatitis.

  1. Coumarin Derivatives from Eryngium campestre1.

    Science.gov (United States)

    Erdelmeier, C A; Sticher, O

    1985-10-01

    Aegelinol benzoate, a new dihydroxanthyletin ester and the known coumarin esters agasyllin and grandivittin, as well as, aegelinol have been isolated from ERYNGIUM CAMPESTRE roots using column chromatography and subsequent semipreparative HPLC. The structures of the compounds have been elucidated by a combination of spectroscopic methods.

  2. 21 CFR 189.130 - Coumarin.

    Science.gov (United States)

    2010-04-01

    ... published in the Federal Register of March 5, 1954 (19 FR 1239). (c) The analytical methods used for detecting coumarin in food are in sections 19.016-19.024 of the “Official Methods of Analysis of the Association of Official Analytical Chemists,” 13th Ed. (1980), which is incorporated by reference. Copies may...

  3. Biogas production from coumarin-rich plants--inhibition by coumarin and recovery by adaptation of the bacterial community.

    Science.gov (United States)

    Popp, Denny; Schrader, Steffi; Kleinsteuber, Sabine; Harms, Hauke; Sträuber, Heike

    2015-09-01

    Plants like sweet clover (Melilotus spp.) are not suitable as fodder for cattle because of harmful effects of the plant secondary metabolite coumarin. As an alternative usage, the applicability of coumarin-rich plants as substrates for biogas production was investigated. When coumarin was added to continuous fermentation processes codigesting grass silage and cow manure, it caused a strong inhibition noticeable as decrease of biogas production by 19% and increase of metabolite concentrations to an organic acids/alkalinity ratio higher than 0.3(gorganic acids) gCaCO3 (-1). Microbial communities of methanogenic archaea were dominated by the genera Methanosarcina (77%) and Methanoculleus (11%). This community composition was not influenced by coumarin addition. The bacterial community analysis unraveled a divergence caused by coumarin addition correlating with the anaerobic degradation of coumarin and the recovery of the biogas process. As a consequence, biogas production resumed similar to the coumarin-free control with a biogas yield of 0.34 LN g(volatile solids) (-1) and at initial metabolite concentrations (∼ 0.2 g(organic acids) gCaCO3 (-1)). Coumarin acts as inhibitor and as substrate during anaerobic digestion. Hence, coumarin-rich plants might be suitable for biogas production, but should only be used after adaptation of the microbial community to coumarin. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  4. Psoralens and coumarins for receptor targeting on epidermal cells

    Energy Technology Data Exchange (ETDEWEB)

    Jetter, M.M.

    1989-01-01

    Specific binding sites have been identified for the psoralens, discrete from DNA, in different epidermal cell lines. These receptors are saturable and are alkylated by the action of psoralens + UVA light. A psoralen receptor has been partially purified and established to be a protein of approximately 20,000 daltons. Inhibition of the binding of epidermal growth factor to its receptor and inhibition of the tyrosine kinase activity of the EGF receptor has been associated with PUVA treatment. These findings conflict with the general assumption that the biological effects of psoralens as photoactive compounds are associated with their ability to covalently bind to and crosslink DNA. In collaboration with Laskin's,laboratory, several classes of psoralen agonists were synthesized. These compounds include coumarins, furocoumarin and benzodipyran-2-one derivatives. The methods of preparation were varied and include variants of the Claisen rearrangement, acid and base-catalyzed condensations. The synthesized compounds were tested for their potential inhibition of {sup 125}I-EGF receptor binding. It was discovered that many of these agents showed potent inhibition activity similar to the psoralens. This data offers the possibility that sites of action, other than DNA, are involved in the mechanism by which photoactivated psoralens modulate epidermal cell lines.

  5. Two new coumarins from Talaromyces flavus.

    Science.gov (United States)

    He, Jun-Wei; Qin, Da-Peng; Gao, Hao; Kuang, Run-Qiao; Yu, Yang; Liu, Xing-Zhong; Yao, Xin-Sheng

    2014-12-12

    Two new coumarins, talacoumarins A (1) and B (2), were isolated from the ethyl acetate extract of the wetland soil-derived fungus Talaromyces flavus BYD07-13. Their structures were elucidated by spectroscopic data (NMR, MS) analyses. The absolute configuration of C-12 in 1 was assigned using the modified Mosher's method, whereas that of C-12 in 2 was deduced via the circular dichroism data of its corresponding [Rh2(OCOCF3)4] complex. Compounds 1 and 2 were evaluated for their anti-Aβ42 aggregation, cytotoxic, and antimicrobial activities. The results showed that the two compounds had moderate anti-Aβ42 aggregation activity, and this is the first report on the Aβ42 inhibitory aggregation activity of coumarins.

  6. Coumarins from the fruits of Cnidium monnieri.

    Science.gov (United States)

    Cai, J N; Basnet, P; Wang, Z T; Komatsu, K; Xu, L S; Tani, T

    2000-04-01

    Two novel biscoumarins, cnidimonal (1) and cnidimarin (2), and two new coumarin derivatives, 5-formylxanthotoxol (3) and 2'-deoxymeranzin hydrate (4), were isolated from a traditional Chinese crude drug, the fruits of Cnidium monnieri, together with 15 known compounds. Among the known compounds, five of the minor compounds were isolated for the first time from this plant. The structures of 1-4 were determined with the use of spectroscopic methods.

  7. Genetically encoded fluorescent coumarin amino acids

    Science.gov (United States)

    Wang, Jiangyun; Xie, Jianming; Schultz, Peter G.

    2010-10-05

    The invention relates to orthogonal pairs of tRNAs and aminoacyl-tRNA synthetases that can incorporate the coumarin unnatural amino acid L-(7-hydroxycoumarin-4-yl) ethylglycine into proteins produced in eubacterial host cells such as E. coli. The invention provides, for example but not limited to, novel orthogonal synthetases, methods for identifying and making the novel synthetases, methods for producing proteins containing the unnatural amino acid L-(7-hydroxycoumarin-4-yl)ethylglycine and related translation systems.

  8. Hepatoprotective coumarins and secoiridoids from Hydrangea paniculata.

    Science.gov (United States)

    Shi, Jing; Li, Chuang-Jun; Yang, Jing-Zhi; Ma, Jie; Wang, Chao; Tang, Jia; Li, Yan; Chen, Hui; Zhang, Dong-Ming

    2014-07-01

    Three new coumarin glucosides (1, 3, 4), and a new secoiridoid glucoside (2), together with one known secoiridoid glucoside (5), were isolated from the stems of Hydrangea paniculata. Their structures were elucidated on the basis of spectroscopic methods, including extensive NMR, MS and CD spectra. At 10 μM, compounds 1-5 showed hepatoprotective activities against DL-galactosamine-induced toxicity in HL-7702 cells. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Coumarins from Angelica Lucida L. - Antibacterial Activities

    Directory of Open Access Journals (Sweden)

    Ioanna Chinou

    2009-07-01

    Full Text Available The first phytochemical investigation of the fruits of Angelica lucida has led to the isolation and characterization of five known coumarins (imperatorin, isoimperatorin, heraclenol, oxypeucedanin hydrate and heraclenin. All isolated compounds were identified by means of spectral and literature data. The extracts and the isolated constituents from A. lucida have been also evaluated for their antimicrobial activity against six Gram positive and negative bacteria, two oral pathogens and three human pathogenic fungi, exhibiting an interesting antimicrobial profile.

  10. Progress in the Chemistry of Naturally Occurring Coumarins.

    Science.gov (United States)

    Sarker, Satyajit D; Nahar, Lutfun

    Coumarins are the largest group of 1-benzopyran derivatives found in plants. The initial member of this group of compounds, coumarin (2H-1-benzopyran-2-one), a fragrant colorless compound, was first isolated from the Tonka bean (Dipteryx odorata, family Fabaceae) in 1820. The name coumarin comes from a French term for the tonka bean, coumarou. Since the discovery of coumarin, several of its derivatives, with umbelliferone (7-hydroxycoumarin) being the most common one, have been reported from various natural sources. The families Apiaceae, Asteraceae, and Rutaceae are the three major plant sources of coumarins.Generally, these plant secondary metabolites may be classified into simple, simple prenylated, simple geranylated, furano, pyrano, sesquiterpenyl and oligomeric coumarins. Using this standard classification, this chapter aims to present an account on the advances of the chemistry of naturally occurring coumarins, as reported in the literature during the period 2013-2015.In Sect. 1, the coumarins are introduced and their generic biosynthetic route discussed briefly. In Sect. 2, the largest of the three sections, various classes of natural coumarins are detailed, with their relevant structures and the citation of appropriate references. In a concluding section, it is highlighted that during the last 3 years, more than 400 coumarins have been reported in the literature. Many of these coumarins have been re-isolations of known compounds from known or new sources, most often associated with various biological activities. However, a substantial number of coumarins bearing new skeletons, especially dimers, prenylated furanocoumarins, sesquiterpenyl, and some unusual coumarins were also reported during the period of 2013-2015.Coumarin chemistry remains one of the major interest areas of phytochemists, especially because of their structural diversity and medicinal properties, along with the wide-ranging bioactivities of these compounds, inclusive of analgesic

  11. Anti-HIV coumarins from Calophyllum seed oil.

    Science.gov (United States)

    Spino, C; Dodier, M; Sotheeswaran, S

    1998-12-15

    The seeds of Calophyllum cerasiferum Vesque (Family-Clusiaceae), and Calophyllum inophyllum Linn. (Family-Clusiaceae) contain several known coumarins, among which were the potent HIV reverse transcriptase inhibitors costatolide and inophyllum P. Calophyllum cerasiferum contained (-)-calanolide B as its major coumarin constituent in significant amount and thus constitute a renewable source of this compound.

  12. Inhibition effects of acetyl coumarines and thiazole derivatives on ...

    Indian Academy of Sciences (India)

    The corrosion inhibition characteristics of acetyl coumarine (AC), bromo acetyl coumarine (BAC) and thiazole derivatives (BTMQ and BTCQ) on the corrosion of zinc in 0.1 M HCl solution were investigated by weight loss, potentiodynamic polarization and impedance techniques. The inhibition efficiency increased with ...

  13. Analysis of fragmentations of coumarins in mass spectrometry using ...

    African Journals Online (AJOL)

    A good correlation was found between electronic charges of atoms and fragmentation processes. In the present study, another series of coumarins with nitrogenated moieties is used to verify the reliability of this method. KEY WORDS: 4,7-Disubstituted coumarins, Nitrogenated moiety, AM1, Electronic charge, Fragmentation, ...

  14. Two new coumarins from the seeds of Solanum indicum.

    Science.gov (United States)

    Yin, Hai-Long; Li, Jie-Hui; Li, Bin; Chen, Li; Li, Jian; Tian, Ying; Liu, Shi-Jun; Zhao, Yong-Kun; Xiao, Yan-Hua; Dong, Jun-Xing

    2014-01-01

    Two new coumarins, (E)-2-(4-hydroxy-3-methoxybenzylidene)-5-methoxy-2H-[1,4]dioxino[2,3-h]chromene-3,9-dione (indicumin E, 1) and 7-hydroxy-6,8-dimethoxy-3-(4'-hydroxy-3'-methoxyphenyl)-coumarin (2), together with two known coumarins isofraxidin (3) and fraxetin (4), were isolated from the Solanum indicum seeds. Their structures were established on the basis of 1D and 2D spectroscopic data. Compound 1 was the rarest coumarinolignoid known to date.

  15. Bioactive sesquiterpene coumarins from Ferula pseudalliacea.

    Science.gov (United States)

    Dastan, Dara; Salehi, Peyman; Reza Gohari, Ahmad; Ebrahimi, Samad Nejad; Aliahmadi, Atousa; Hamburger, Matthias

    2014-08-01

    One new and five known sesquiterpene coumarins were isolated from the roots of Ferula pseudalliacea. The structures were elucidated by 1D and 2D NMR, and HR-ESIMS data as 4'-hydroxy kamolonol acetate (1), kamolonol (2), szowitsiacoumarin A (3), farnesiferon B (4), farnesiferol C (5), and flabellilobin A (6). The absolute configuration of compounds 1, 2, and 4 was established by comparison of experimental and simulated electronic circular dichroism spectra using time dependence density function theory. 4'-Hydroxy kamolonol acetate and kamolonol showed antibacterial activity against Heliobacter pylori and Staphylococcus aureus at a concentration of 64 µg/mL. Kamolonol, 4'-hydroxy kamolonol acetate, and farnesiferon B displayed a cytotoxic activity in HeLa cells, with an IC50 of 3.8, 4.5, and 7.7 µM, respectively. Georg Thieme Verlag KG Stuttgart · New York.

  16. A potential low-coumarin cinnamon substitute: Cinnamomum osmophloeum leaves.

    Science.gov (United States)

    Yeh, Ting-Feng; Lin, Chun-Ya; Chang, Shang-Tzen

    2014-02-19

    The essential oils from leaves of Taiwan's indigenous cinnamon (Cinnamomum osmophloeum ct. cinnamaldehyde) have similar constituents as compared to that from commercial bark cinnamons. This indigenous cinnamon has been proven to have excellent bioactivities. To understand whether this indigenous cinnamon contains a high level of the hepatotoxic compound, coumarin, as often seen in Cassia cinnamons, current research focused on determining the coumarin content in this indigenous cinnamon and screening the low-coumarin clones. The results demonstrated that the coumarin contents in all tested indigenous cinnamon clones were much lower than that found in Cassia cinnamons. In addition, this indigenous cinnamon contains about 80% (w/w) of cinnamaldehyde and 0.4-2.7% (w/w) of eugenol in its leaf essential oils. This combination could provide this indigenous cinnamon a better shelf life compared to that of regular commercial cinnamons. These results suggested that leaves of this indigenous cinnamon could be a potential resource for a safer cinnamon substitute.

  17. Siamenols A-D, four new coumarins from Mammea siamensis.

    Science.gov (United States)

    Prachyawarakorn, Vilailak; Mahidol, Chulabhorn; Ruchirawat, Somsak

    2006-06-01

    Further investigation of the dichloromethane extract of the twigs of Mammea siamensis led to the isolation of four novel coumarins, named siamenols A-D (1-4) together with three known xanthones. The structures of the new coumarins were elucidated by spectroscopic analysis, including 2D NMR spectroscopic data. In addition, the absolute stereochemistry of hydroxyl group of siamenol C (3) was determined to be S configuration by using modified Mosher's method.

  18. Coumarins from the leaves of Bambusa pervariabilis McClure.

    Science.gov (United States)

    Sun, Jia; Yue, Yong-De; Tang, Feng; Guo, Xue-Feng

    2010-03-01

    A new pyrone-coumarin, 7,8-dihydroxy-3-(3-hydroxy-4-oxo-4H-pyran-2-yl)-2H-chromen-2-one (1), along with two known coumarins, scopoletin (2) and scopolin (3), was isolated from the 95% EtOH extract of the leaves of Bambusa pervariabilis McClure. Their structures were determined on the basis of spectroscopic techniques and chemical methods.

  19. [Allelopathy effects of ferulic acid and coumarin on Microcystis aeruginosa].

    Science.gov (United States)

    Guo, Ya-Li; Fu, Hai-Yan; Huang, Guo-He; Gao, Pan-Feng; Chai, Tian; Yan, Bin; Liao, Huan

    2013-04-01

    The inhibitory effects and allelopathy mechanism of ferulic acid and coumarin on Microcystis aeruginosa were investigated by measuring the D680 value, the content of chlorophyll-a, the electrical conductivity (EC) and superoxide anion radical O*- value. Ferulic acid and coumarin had allelopathic effects on the growth of M. aeruginosa and promoted the physiological metabolism at low concentrations while inhibited the metabolism at high concentrations. Obvious inhibitory effects were observed when the concentration of ferulic acid or coumarin was over 100 mg x L(-1). The average inhibitory rates reached 80.3% and 58.0% after six days when the concentration of ferulic acid or coumarin was 200 mg x L(-1). The content of chlorophyll-a was decreased while the EC value and O2*- concentration were promoted by higher concentrations of ferulic acid or coumarin, suggesting that the growth of algae was inhibited probably by the damage of cell membrane, increase in the content of O2*- and decrease in the content of chlorophyll-a. In addition, seed germination test elucidated that Ferulic acid was safer than Coumarin.

  20. A fluorescent receptor assay for benzodiazepines using coumarin labeled desethylflumazenil as ligand

    NARCIS (Netherlands)

    Janssen, M.J; Ensing, K; de Zeeuw, R.A

    2001-01-01

    This article describes a novel nonisotopic receptor assay for benzodiazepines with fluorescence detection, As labeled ljgand (coumarin-labeled desethylflumazenil, CLDEF), a metabolite of the benzodiazepine antagonist flumazenil (desetheylflumazenil, Ro15-3890) has been coupled to a coumarin

  1. Synthesis of coumarin or ferrocene labeled nucleosides via Staudinger ligation

    Directory of Open Access Journals (Sweden)

    Kois Pavol

    2006-11-01

    Full Text Available Abstract Background Reaction of azides with triaryl phosphines under mild conditions gives iminophosphoranes which can react with almost any kind of electrophilic reagent, e.g. aldehydes/ketones to form imines or esters to form amides. This so-called Staudinger ligation has been employed in a wide range of applications as a general tool for bioconjugation including specific labeling of nucleic acids. Results A new approach for the preparation of labeled nucleosides via intermolecular Staudinger ligation is described. Reaction of azidonucleosides with triphenylphosphine lead to iminophosphorane intermediates, which react subsequently with derivatives of coumarin or ferrocene to form coumarin or ferrocene labeled nucleosides. Fluorescent properties of coumarin labeled nucleosides are determined. Conclusion New coumarin and ferrocene labeled nucleosides were prepared via intermolecular Staudinger ligation. This reaction joins the fluorescent coumarin and biospecific nucleoside to the new molecule with promising fluorescent and electrochemical properties. The isolated yields of products depend on the structure of azidonucleoside and carboxylic acids. A detailed study of the kinetics of the Staudinger ligation with nucleoside substrates is in progress.

  2. Spectral and quantum-mechanical characterizations of 7-amino-4-trifluoromethyl coumarin

    Science.gov (United States)

    Benchea, Andreea Celia; Gaina, Marius; Dorohoi, Dana Ortansa

    2017-01-01

    Coumarins are crystalline compounds utilized in pharmaceutical, food and cosmetic industries. Our study refers to quantum-mechanical and spectral characterization of 7-amino-4-trifluoromethyl coumarin (7-NH2-4-CF3-coumarin or coumarin 151) in order to estimate its stability, reactivity and biological activity. The contribution of different types of interactions to the spectral shifts in homogeneous solutions and the limits in which the excited state dipole moment of the studied molecule can vary are established by solvatochromic study.

  3. Design and Synthesis of a Coumarin-based Acidichromic Colorant

    Directory of Open Access Journals (Sweden)

    Ding-Yah Yang

    2007-07-01

    Full Text Available This paper describes the fine-tuning of the acidichromic properties of a coumarin-containing colorant 1 by incorporation of electron-donating and electron-withdrawing substituents on the coumarin moiety. Colorant 1 can undergo two distinct and reversible color changes under both strongly acidic and basic conditions, but not in the presence of gaseous ammonia. The results indicated that the bromo-substituted compound 5b changes from red to yellow when exposed to gaseous ammonia, both in solution and on polycarbonate film, suggesting that an electron-withdrawing group at the 7-position of the coumarin moiety made the enolic hydrogen on 5b more susceptible to deprotonation by a base than in the unsubstituted compound 1.

  4. Design and synthesis of a coumarin-based acidichromic colorant.

    Science.gov (United States)

    Lin, Shih-Lun; Kuo, Pei-Yu; Yang, Ding-Yah

    2007-07-06

    This paper describes the fine-tuning of the acidichromic properties of a coumarin-containing colorant 1 by incorporation of electron-donating and electron-withdrawing substituents on the coumarin moiety. Colorant 1 can undergo two distinct and reversible color changes under both strongly acidic and basic conditions, but not in the presence of gaseous ammonia. The results indicated that the bromo-substituted compound 5b changes from red to yellow when exposed to gaseous ammonia, both in solution and on polycarbonate film, suggesting that an electron-withdrawing group at the 7-position of the coumarin moiety made the enolic hydrogen on 5b more susceptible to deprotonation by a base than in the unsubstituted compound 1.

  5. A Facile, Choline Chloride/Urea Catalyzed Solid Phase Synthesis of Coumarins via Knoevenagel Condensation

    Directory of Open Access Journals (Sweden)

    Hosanagara N. Harishkumar

    2011-01-01

    Full Text Available The influence of choline chloride/urea ionic liquid in solid phase on the Knoevenagel condensation is demonstrated. The active methylene compounds such as meldrum’s acid, diethylmalonate, ethyl cyanoacetate, dimethylmalonate, were efficiently condensed with various salicylaldehydes in presence of choline chloride/urea ionic liquid without using any solvents or additional catalyst. The reaction is remarkably facile because of the air and water stability of the catalyst, and needs no special precautions. The reactions were completed within 1hr with excellent yields (95%. The products formed were sufficiently pure, and can be easily recovered. The use of ionic liquid choline chloride/urea in solid phase offered several significant advantages such as low cost, greater selectivity and easy isolation of products.

  6. A cost-effective and green aqueous synthesis of 3-substituted coumarins catalyzed by potassium phthalimide

    Directory of Open Access Journals (Sweden)

    H. Kiyani

    2015-10-01

    Full Text Available An efficient procedure for the synthesis of various 2-imino-2H-chromene-3-carbonitriles, 2-oxo-2H-chromene-3-carbonitriles as well as 2-oxo-2H-chromene-3-carboxylic acids is reported. It has been found that potassium phthalimide (PPI catalyse the Knoevenagel condensation reaction of salicylaldehydes and activated β-dicarbonyl compounds efficiently under aqueous conditions at room temperature. This approach provides many merits such as high yields of products, clean, simple work-up, waste free, mild reaction conditions, commercially available organocatalyst, and the use of water as environmentally benign solvent. DOI: http://dx.doi.org/10.4314/bcse.v29i3.13

  7. Synthesis and Sensing Applications of Fluorescent 3-Cinnamoyl Coumarins

    Directory of Open Access Journals (Sweden)

    Preeti Yadav

    2015-12-01

    Full Text Available We have synthesized two novel fluorescent 3-(4-diethylaminocinnamoyl coumarins that exhibit fluorescence quenching upon exposure to a nerve agent simulant, diethylchlorophosphate (DCP, providing a basis for rapid and sensitive DCP chemosensing. Furthermore, these coumarin derivatives display two-photon fluorescence upon illumination with near-infrared laser pulses and their two-photon (TP absorption cross-section was evaluated. The potential for TP bio-imaging of these compounds was investigated by their cellular uptake in HeLa cells by TP confocal microscopy.

  8. Synthesis of mixed-chain phosphatidylcholines including coumarin fluorophores for FRET-based kinetic studies of phospholipase A(2) enzymes.

    Science.gov (United States)

    Wang, Manlin; Pinnamaraju, Susmitha; Ranganathan, Radha; Hajdu, Joseph

    2013-01-01

    Phospholipase A2 (PLA2) enzymes catalyze the hydrolysis of the sn-2 ester linkage of glycerophospholipids to produce fatty acids and lysophospholipids. A significant number of mammalian phospholipases comprise a family of secreted PLA2 enzymes, found in specific tissues and cellular locations, exhibiting unique enzymatic properties and distinct biological functions. Development of new real-time spectrofluorimetric PLA2 assays should facilitate the kinetic characterization and mechanistic elucidation of the isozymes in vitro, with the potential applicability to detect and measure catalytic PLA2 activity in tissues and cellular locations. Here we report a new synthesis of double-labeled phosphatidylcholine analogs with chain-terminal reporter groups including coumarin fluorophores for fluorescence resonance energy transfer (FRET)-based kinetic studies of PLA2 enzymes. The use of coumarin derivatives as fluorescent labels provides reporter groups with substantially decreased size compared to the first generation of donor-acceptor pairs of fluorescent phospholipids. The key advantage of the design is to interfere less with the physicochemical properties of the acyl chains, thereby improving the substrate quality of the synthetic probes. In order to assess the impact of the fluorophore substituents on the catalytic hydrolysis and on the phospholipid packing in the lipid-water interface of the assay, we used the experimentally determined specific activity of bee-venom phospholipase A2 as a model for the secretory PLA2 enzymes. Specifically, the rate of PLA2 hydrolysis of the coumarin labeled phosphatidylcholine analogs was less than three times slower than the natural substrate dipalmitoyl phosphatidylcholine (DPPC) under the same experimental conditions. Furthermore, variation of the mole fraction of the synthetic phosphatidylcholine vs. that of the natural DPPC substrate showed nearly ideal mixing behavior in the phospholipid-surfactant aggregates of the assay. The

  9. Synthesis of mixed-chain phosphatidylcholines including coumarin fluorophores for FRET-based kinetic studies of phospholipase A2 enzymes

    Science.gov (United States)

    Wang, Manlin; Pinnamaraju, Susmitha; Ranganathan, Radha; Hajdu, Joseph

    2013-01-01

    Phospholipase A2 (PLA2) enzymes catalyze the hydrolysis of the sn-2 ester linkage of glycerophospholipids to produce fatty acids and lysophospholipids. A significant number of mammalian phospholipases comprise a family of secreted PLA2 enzymes, found in specific tissues and cellular locations, exhibiting unique enzymatic properties and distinct biological functions. Development of new real-time spectrofluorimetric PLA2 assays should facilitate the kinetic characterization and mechanistic elucidation of the isozymes in vitro, with the potential applicability to detect and measure catalytic PLA2 activity in tissues and cellular locations. Here we report a new synthesis of double-labeled phosphatidylcholine analogues with chain-terminal reporter groups including coumarin fluorophores for fluorescence resonance energy transfer (FRET)-based kinetic studies of PLA2 enzymes. The use of coumarin derivatives as fluorescent labels provides reporter groups with substantially decreased size compared to the first generation of donor-acceptor pairs of fluorescent phospholipids. The key advantage of the design is to interfere less with the physicochemical properties of the acyl chains, thereby improving the substrate quality of the synthetic probes. In order to assess the impact of the fluorophore substituents on the catalytic hydrolysis and on the phospholipid packing in the lipid-water interface of the assay, we used the experimentally determined specific activity of bee-venom phospholipase A2 as a model for the secretory PLA2 enzymes. Specifically, the rate of PLA2 hydrolysis of the coumarin labeled phosphatidylcholine analogues was less than three times slower than natural substrate dipalmitoyl phosphatidylcholine (DPPC) under the same experimental conditions. Furthermore, variation of the mole fraction of the synthetic phosphatidylcholine vs. that of the natural DPPC substrate showed nearly ideal mixing behavior in the phospholipid-surfactant aggregates of the assay. The

  10. Characterization of coumarin-specific prenyltransferase activities in Citrus limon peel.

    Science.gov (United States)

    Munakata, Ryosuke; Inoue, Tsuyoshi; Koeduka, Takao; Sasaki, Kanako; Tsurumaru, Yusuke; Sugiyama, Akifumi; Uto, Yoshihiro; Hori, Hitoshi; Azuma, Jun-Ichi; Yazaki, Kazufumi

    2012-01-01

    Coumarins, a large group of polyphenols, play important roles in the defense mechanisms of plants, and they also exhibit various biological activities beneficial to human health, often enhanced by prenylation. Despite the high abundance of prenylated coumarins in citrus fruits, there has been no report on coumarin-specific prenyltransferase activity in citrus. In this study, we detected both O- and C-prenyltransferase activities of coumarin substrates in a microsome fraction prepared from lemon (Citrus limon) peel, where large amounts of prenylated coumarins accumulate. Bergaptol was the most preferred substrate out of various coumarin derivatives tested, and geranyl diphosphate (GPP) was accepted exclusively as prenyl donor substrate. Further enzymatic characterization of bergaptol 5-O-geranyltransferase activity revealed its unique properties: apparent K(m) values for GPP (9 µM) and bergaptol (140 µM) and a broad divalent cation requirement. These findings provide information towards the discovery of a yet unidentified coumarin-specific prenyltransferase gene.

  11. Anti-inflammatory coumarins from Paramignya trimera.

    Science.gov (United States)

    Tuan Anh, Hoang Le; Kim, Dong-Cheol; Ko, Wonmin; Ha, Tran Minh; Nhiem, Nguyen Xuan; Yen, Pham Hai; Tai, Bui Huu; Truong, Luu Hong; Long, Vu Ngoc; Gioi, Tran; Hong Quang, Tran; Minh, Chau Van; Oh, Hyuncheol; Kim, Youn-Chul; Kiem, Phan Van

    2017-12-01

    Paramignya trimera (Oliv.) Burkill (Rutaceae) has been used to treat liver diseases and cancer. However, the anti-inflammatory effects of this medicinal plant and its components have not been elucidated. This study investigated chemical constituents of the P. trimera stems and evaluated anti-inflammatory effects of isolated compounds. Cytotoxicity of isolated compounds (5-40 μM) toward BV2 cells was tested using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) for 24 h. Inhibitory effects of isolated compounds (5-40 μM) on nitrite and PGE2 concentrations were determined using Griess reaction and PGE2 ELISA kit, respectively (pretreated with the compounds for 3 h and then stimulated for 18 h with LPS). Inhibitory effects of compounds (5-40 μM) on iNOS and COX-2 protein expression were evaluated by Western blot analysis (pretreated with the compounds for 3 h and then stimulated for 24 h with LPS). Seven coumarins were isolated and identified as: ostruthin (1), ninhvanin (2), 8-geranyl-7-hydroxycoumarin (3), 6-(6',7'-dihydroxy-3',7'-dimethylocta-2'-enyl)-7-hydroxycoumarin (4), 6-(7-hydroperoxy-3,7-dimethylocta-2,5-dienyl)-7-hydroxycoumarin (5), 6-(2-hydroxyethyl)-2,2-dimethyl-2H-1-benzopyran (6), and luvangetin (7). Compounds 1-4 and 7 inhibited NO and PGE2 production in LPS-stimulated BV2 cells, with IC50 values ranging from 9.8 to 46.8 and from 9.4 to 52.8 μM, respectively. Ostruthin (1) and ninhvanin (2) were shown to suppress LPS-induced iNOS and COX-2 protein expression. The present study provides a scientific rationale for the use of P. trimera in the prevention and treatment of neuroinflammatory diseases. Ostruthin and ninhvanin might have potential therapeutic effects and should be considered for further development as new anti-neuroinflammatory agents.

  12. Expeditious synthesis of coumarin-pyridone conjugates molecules ...

    Indian Academy of Sciences (India)

    RAJNI KHAJURIA

    widespread occurrence in natural products and exhibi- tion of diverse pharmacological activities including anti- ... occurrence in many biologically active natural products, therapeutics and synthetic compounds.10 .... Synthesis and anti-microbial evaluation of coumarin-pyridone conjugates. 1551 bacterial cultures and at 25.

  13. Current perspectives on dental patients receiving coumarin anticoagulant therapy.

    Science.gov (United States)

    Herman, W W; Konzelman, J L; Sutley, S H

    1997-03-01

    Despite approximately 40 years of experience with oral anticoagulant drugs, controversy still exists about the safety of dental treatment in a patient receiving this therapy. The authors review the topic in depth and offer detailed recommendations for the dental management of patients receiving coumarin anticoagulant therapy.

  14. Tuning Luminescent Converters Based on Coumarins and Their Photostability

    Science.gov (United States)

    Tsaplev, Yu. B.; Trofimov, A. V.; Pershukevich, P. P.; Pavich, T. A.; Zak, P. P.; Trofimova, N. N.; Lapina, V. A.

    2017-11-01

    We have studied the feasibility of using luminophores in the coumarin series in luminescent filters for correcting the spectra of light-emitting diode (LED) light sources. Fine tuning of the emission spectra of luminophores in polymer matrices is achieved by introducing nonionic surfactants into the matrix. We propose a method for estimating the photostability of luminescent filters and we determine the photostability parameters.

  15. Trypanocidal constituents in plants: 7. Mammea-type coumarins

    Directory of Open Access Journals (Sweden)

    Ricardo Reyes-Chilpa

    2008-08-01

    Full Text Available Calophyllum brasiliense and Mammea americana (Clusiaceae are two trees from the tropical rain forests of the American continent. A previous screening showed high trypanocidal activity in the extracts of these species. Several mammea-type coumarins, triterpenoids and biflavonoids were isolated from the leaves of C. brasiliense. Mammea A/AA was obtained from the fruit peels of M. americana. These compounds were tested in vitro against epimastigotes and trypomastigotes of Trypanosoma cruzi, the etiologic agent of Chagas disease. The most potent compounds were mammea A/BA, A/BB, A/AA, A/BD and B/BA, with MC100 values in the range of 15 to 90 g/ml. Coumarins with a cyclized ,-dimethylallyl substituent on C-6, such as mammea B/BA, cyclo F + B/BB cyclo F, and isomammeigin, showed MC100 values > 200 g/ml. Several active coumarins were also tested against normal human lymphocytes in vitro, which showed that mammea A/AA and A/BA were not toxic. Other compounds from C. brasiliense, such as the triterpenoids, friedelin, canophyllol, the biflavonoid amentoflavone, and protocatechuic and shikimic acids, were inactive against the epimastigotes. The isopropylidenedioxy derivative of shikimic acid was inactive, and its structure was confirmed by X-ray diffraction. Our results suggest that mammea-type coumarins could be a valuable source of trypanocidal compounds.

  16. Cytotoxic Coumarins from the Bark of Mammea siamensis

    DEFF Research Database (Denmark)

    Ngo, Ngoc Trang Nhu; Nguyen, Vy Thuy; Vo, Hoa Van

    2010-01-01

    -NMR) and preparation of methylated derivatives. The four coumarins, surangins C and D and theraphins B and C, were tested for inhibition of cell proliferation in DLD-1 (colon cancer), MCF-7 (breast adenocarcinoma), HeLa (human cervical cancer) and NCI-H460 (human lung cancer) cell lines using the sulforhodamine B (SRB...

  17. Probing the binding of coumarins and cyclothialidines to DNA gyrase

    DEFF Research Database (Denmark)

    Kampranis, S C; Gormley, N A; Tranter, R

    1999-01-01

    DNA gyrase is the target of a number of antibacterial agents, including the coumarins and the cyclothialidines. To extend our understanding of the mechanism of action of these compounds, we have examined the previously published crystal structures of the complexes between the 24 kDa fragment of Gyr...

  18. Variation in coumarin accumulation by stem age in Dendrobium ...

    African Journals Online (AJOL)

    In this study, laser scanning confocal microscopy was applied to determine the localization and relative quantity of coumarins in stems of Dendrobium thyrsiflorum Rchb. f. (Orchidaceae) when plants entered profuse flowering and initial fruit period during reproductive growth stage. Stems at the two growth stages were ...

  19. GAS PHASE ION CHEMISTRY OF COUMARINS: AB INITIO ...

    African Journals Online (AJOL)

    B. S. Chandravanshi

    ABSTRACT. The gas phase ion chemistry of coumarins using electron ionization (EI), positive chemical ionization (PCI) and negative chemical ionization (NCI) in a time of flight and quadrupole mass spectrometer. (qMS) coupled to a gas chromatograph is outlined. The observations in NCI mode were complimented with Ab.

  20. Terpenylated coumarins as SIRT1 activators isolated from Ailanthus altissima

    DEFF Research Database (Denmark)

    Dao, Trong-Tuan; Tran, Tien-Lam; Kim, Jayeon

    2012-01-01

    activity in an in vitro SIRT1-NAD/NADH assay and an in vivo SIRT1-p53 luciferase assay. These compounds also increased the NAD-to-NADH ratio in HEK293 cells. The present results suggest that terpenylated coumarins from A. altissima have a direct stimulatory effect on SIRT1 deacetylation activity and may...

  1. Trypanocidal constituents in plants: 7. Mammea-type coumarins.

    Science.gov (United States)

    Reyes-Chilpa, Ricardo; Estrada-Muñiz, Elizabeth; Vega-Avila, Elisa; Abe, Fumiko; Kinjo, Junei; Hernández-Ortega, Simón

    2008-08-01

    Calophyllum brasiliense and Mammea americana (Clusiaceae) are two trees from the tropical rain forests of the American continent. A previous screening showed high trypanocidal activity in the extracts of these species. Several mammea-type coumarins, triterpenoids and biflavonoids were isolated from the leaves of C. brasiliense. Mammea A/AA was obtained from the fruit peels of M. americana. These compounds were tested in vitro against epimastigotes and trypomastigotes of Trypanosoma cruzi, the etiologic agent of Chagas disease. The most potent compounds were mammea A/BA, A/BB, A/AA, A/BD and B/BA, with MC100 values in the range of 15 to 90 microg/ml. Coumarins with a cyclized gamma,gamma-dimethylallyl substituent on C-6, such as mammea B/BA, cyclo F + B/BB cyclo F, and isomammeigin, showed MC100 values > 200 microg/ml. Several active coumarins were also tested against normal human lymphocytes in vitro, which showed that mammea A/AA and A/BA were not toxic. Other compounds from C. brasiliense, such as the triterpenoids, friedelin, canophyllol, the biflavonoid amentoflavone, and protocatechuic and shikimic acids, were inactive against the epimastigotes. The isopropylidenedioxy derivative of shikimic acid was inactive, and its structure was confirmed by X-ray diffraction. Our results suggest that mammea-type coumarins could be a valuable source of trypanocidal compounds.

  2. Coumarin derivatives from Ainsliaea fragrans and their anticoagulant activity

    Science.gov (United States)

    Lei, Liang; Xue, Yong-bo; Liu, Zhong; Peng, Si-si; He, Yan; Zhang, Yang; Fang, Rong; Wang, Jian-ping; Luo, Zeng-wei; Yao, Guang-min; Zhang, Jin-wen; Zhang, Geng; Song, Hong-ping; Zhang, Yong-hui

    2015-01-01

    Coumarin derivatives are an important class of C6–C3 plant metabolites that show a variety of bioactivities. Currently, most clinical anticoagulant agents are coumarins, such as warfarin, dicoumarol and acenocoumarol, and patients taking these drugs must be monitored for adverse reactions. In a search for safe and effective anticoagulant compounds from Chinese herbal medicine, a screening procedure on the whole plant of Ainsliaea fragrans was performed. The phytochemical investigation of this plant afforded five new coumarin derivatives, including a pair of natural 4-hydroxycoumarin enantiomers (1), a pair of coumarin enantiomers with a rare polycyclic pyrano[3-2c] carbon skeleton (2) and a 7-hydroxycoumarin derivative (3), together with 5 known biogenetically related compounds (4–8). Enantioseparation of 1 and 2 produced optically pure compounds 1a, 1b, 2a and 2b. The absolute configurations of the new compounds were confirmed by single-crystal X-ray diffraction analysis. In addition, we evaluated the anticoagulant activity of all isolates via activated partial thromboplastin time (APTT), thrombin time (TT) and prothrombin time (PT) assays in vitro and in vivo. Of note, compound 3 displayed potent anticoagulant activity and no significant hepatic or renal toxicity, which could make it a promising agent for further preclinical evaluation for preventing abnormal blood clotting. PMID:26315062

  3. Synthesis, in vitro anticancer and antibacterial activities and in silico studies of new 4-substituted 1,2,3-triazole-coumarin hybrids.

    Science.gov (United States)

    Kraljević, Tatjana Gazivoda; Harej, Anja; Sedić, Mirela; Pavelić, Sandra Kraljević; Stepanić, Višnja; Drenjančević, Domagoj; Talapko, Jasminka; Raić-Malić, Silvana

    2016-11-29

    The 4-substituted 1,2,3-triazole core in designed coumarin hybrids (4-35) with diverse physicochemical properties was introduced by eco-friendly copper(I)-catalyzed Huisgen 1,3-dipolar cycloaddition under microwave irradiation. Coumarin-1,2,3-triazole-benzofused heterocycle hybrids emerged as the class of compounds exhibiting the highest antiproliferative activity. The strong relationship between lipophilicity and antiproliferative activities was observed indicating that lipophilic 1,2,3-triazole-coumarin hybrids containing phenylethyl (13), 3,5-difluorophenyl (14), 5-iodoindole (30) and benzimidazole (33 and 35) subunits showed the most potent cytostatic effects. The 7-methylcoumarin-1,2,3-triazole-2-methylbenzimidazole hybrid 33 can be highlighted as a lead that exerted the highest cytotoxicity against hepatocellular carcinoma HepG2 cells with IC 50 value of 0.9 μM and high selectivity (SI = 50). This compound induced cell death, mainly due to early apoptosis. Strong antiproliferative effect of 33 could be associated with its inhibition of 5-lipoxygenase (5-LO) activity and perturbation of sphingolipid signaling by interfering with intracellular acid ceramidase (ASAH) activity. Outlined considerable effect of lipophilicity on antiproliferative activity was not observed for antibacterial activity. The compounds with p-pentylphenyl (17), 2-chloro-4-fluorobenzenesulfonamide (23) and dithiocarbamate (27) moiety were endowed with high selectivity against Enterococcus species. Moreover, these compounds were found to be superior in inhibiting the growth of clinically isolated vancomycin-resistant Enterococcus faecium, while the reference antibiotics exhibited the lack of activity. Our findings indicate that coumarin-1,2,3-triazole could be used as the scaffold for structural optimization to develop more potent and selective anticancer agents and encourage further development of novel structurally related analogs of 33 as more effective 5-LO inhibitors. Copyright

  4. Catalyzing RE Project Development

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Kate; Elgqvist, Emma; Walker, Andy; Cutler, Dylan; Olis, Dan; DiOrio, Nick; Simpkins, Travis

    2016-09-01

    This poster details how screenings done with REopt - NREL's software modeling platform for energy systems integration and optimization - are helping to catalyze the development of hundreds of megawatts of renewable energy.

  5. [Biotransformation of 4-methyl-7-allyloxy coumarin by transgenic hairy roots of Polygonum multiflorum].

    Science.gov (United States)

    Liang, Yan; Deng, Wen-juan; Zhou, Liang-bin; Yan, Chun-yan; Yu, Rong-min

    2011-06-01

    To synthesis 4-methyl-7-allyloxy coumarin by Williamson etherification from 4-methyl-7-hydroxy coumarin and apply as a substrate in hairy roots of Polygonum multiflorum. The synthesis reaction of 4-methyl-7-allyloxy coumarin used the allyl bromide and potassium carbonate as catalysts, and acetone as solvent reacted for 17 hours, then the product was isolated. 4-methyl-7-allyloxy coumarin was added into the media of supension transgenic hairy roots of Polygonum multiflorum which had been precultured for 8 d, and then co-cultured for another 7 d. The biotransformation products were detected by TLC and HPLC and isolated by various chromatographic methods. Two biotransformation products, 4-methyl-7-hydroxy coumarin and 4-methyl-coumarin-7-O-beta-D-glucoside were isolated and identified. Hairy roots of Polygonum multiflorum contains not only glycosyltransferase but also hydrolysis enzymes.

  6. Chromones and coumarins from the dried fructus of Cnidium monnieri.

    Science.gov (United States)

    Zhao, Jianyu; Zhou, Min; Liu, Yan; Zhang, Guolin; Luo, Yinggang

    2011-07-01

    Chemical investigations on the ethanolic extract of the dried fructus of Cnidium monnieri offered three chromones and eight coumarins. Among them, a new chromone and a new coumarin were identified and elucidated as 5,7-dihydroxy-6-[(2Z)-4-(β-d-glucopyranosyl)oxy-3- methylbut-2-enyl]-2-hydroxymethyl-4H-1-benzopyran-4-one (1, hydroxycnidimoside A) and (rel 1'S,2'R)-8-(2,3-epoxy-1-hydroxy-3-methylbutyl)-7-methoxycoumarin (8, hydroxyosthole epoxide), respectively, by extensive analyses of spectroscopic data including 1- and 2-D NMR, MS, UV, OR, IR, and HRMS data. The other known compounds were identified by analyses of spectroscopic data and by comparison with literature reported. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Two benzoyl coumarin amide fluorescence chemosensors for cyanide anions

    Science.gov (United States)

    Wang, Zian; Wu, Qianqian; Li, Jiale; Qiu, Shuang; Cao, Duxia; Xu, Yongxiao; Liu, Zhiqiang; Yu, Xueying; Sun, Yatong

    2017-08-01

    Two new benzoyl coumarin amide derivatives with ortho hydroxyl benzoyl as terminal group have been synthesized. Their photophysical properties and recognition properties for cyanide anions in acetonitrile have also been examined. The influence of electron donating diethylamino group in coumarin ring and hydroxyl in benzoyl group on recognition properties was explored. The results indicate that the compounds can recognize cyanide anions with obvious absorption and fluorescence spectral change and high sensitivity. The import of diethylamine group increases smartly the absorption ability and fluorescence intensity of the compound, which allows the recognition for cyanide anions can be observed by naked eyes. The in situ hydrogen nuclear magnetic resonance spectra combining photophysical properties change and job's plot data confirm that Michael addition between the chemosensors and cyanide anions occurs. Molecular conjugation is interrupted, which leads to fluorescence quenching. At the same time, there is a certain extent hydrogen bond reaction between cyanide and hydroxyl group in the compounds, which is beneficial to the recognition.

  8. Bioactive kaurane diterpenes and coumarins from Fortunella margarita.

    Science.gov (United States)

    el-Shafae, A M; Ibrahim, M A

    2003-02-01

    Two bioactive pyranocoumarins 1 (sesselin) and 3 (xanthyletin) and one prenylated coumarin 2 (suberosin), beside three rare kaurene diterpenes 5-7 were isolated from the roots of Fortunella margarita. Their structures were determined from their spectroscopic data, including 1H/13C 2D NMR experiments. The kaurene diterpenes 5-7 are reported in Rutaceae for the first time. Diterpene 5 was found to be a potent stimulator of uterine contraction; it also caused stimulation of brain activity.

  9. Coumarins from Angelica lucida L.--antibacterial activities.

    Science.gov (United States)

    Widelski, Jaroslaw; Popova, Milena; Graikou, Konstantia; Glowniak, Kazimierz; Chinou, Ioanna

    2009-07-27

    The first phytochemical investigation of the fruits of Angelica lucida has led to the isolation and characterization of five known coumarins (imperatorin, isoimperatorin, heraclenol, oxypeucedanin hydrate and heraclenin). All isolated compounds were identified by means of spectral and literature data. The extracts and the isolated constituents from A. lucida have been also evaluated for their antimicrobial activity against six Gram positive and negative bacteria, two oral pathogens and three human pathogenic fungi, exhibiting an interesting antimicrobial profile.

  10. New sesquiterpene coumarins from the roots of Ferula flabelliloba.

    Science.gov (United States)

    Iranshahi, Mehrdad; Kalategi, Farhad; Sahebkar, Amirhossein; Sardashti, Alireza; Schneider, Bernd

    2010-02-01

    Three new sesquiterpene coumarins, namely, farnesiferone B (1), flabellilobin A (2) and flabellilobin B (3), together with nine known compounds, ligupersin A, 7-epi-gamma-eudesmol, persicasulfide A, conferdione, umbelliprenin, conferone, feselol, lehmferin and farnesiferol B were isolated from the roots of Ferula flabelliloba Rech. f. & Aell. (Apiaceae). The structures of these compounds were elucidated by various 1- and 2-D NMR techniques as well as HREIMS.

  11. Monoterpenoid coumarins from the peels of Clausena lansium.

    Science.gov (United States)

    Deng, Hui-Dong; Mei, Wen-Li; Guo, Zhi-Kai; Liu, Shuai; Zuo, Wen-Jian; Dong, Wen-Hua; Li, Shao-Peng; Dai, Hao-Fu

    2014-07-01

    A phytochemical investigation on the peels of Clausena lansium (Lour.) Skeels led to the isolation of two new monoterpenoid coumarins, named clauslactone V (1) and clauslactone W (2), together with three known analogues (3-5). Their structures were elucidated by spectroscopic techniques (UV, IR, MS, 1D and 2D NMR). All the compounds were evaluated for hypoglycemic activity, and compounds 1-5 showed α-glucosidase inhibitory activity in vitro. Georg Thieme Verlag KG Stuttgart · New York.

  12. QSAR models for antioxidant activity of new coumarin derivatives.

    Science.gov (United States)

    Erzincan, P; Saçan, M T; Yüce-Dursun, B; Danış, Ö; Demir, S; Erdem, S S; Ogan, A

    2015-01-01

    This study presents 37 new antioxidant coumarin derivatives and strategies for structural modification to improve their antioxidant activities, the main ferric-reducing antioxidant power (FRAP) assay used to evaluate their antioxidant properties and the generation of validated quantitative structure-activity (antioxidant activity) relationship (QSAR) models. In an attempt to generate QSAR models, structures of all coumarin derivatives in the data set were fully optimized by semi-empirical PM6 method using SPARTAN 10 software. Descriptors were calculated by DRAGON 6.0 software. Multiple linear regression (MLR) models were developed with different training/test set combinations using QSARINS 2.2.1 software. Robustness, reliability and predictive power of the models were tested by internal and external validations. Applicability domain of the best two-descriptor model (nTR = 30; r(2) = 0.924; RMSETR = 0.213; nTEST = 7; r(2)ext = 0.887; RMSEext = 0.255; CCCext = 0.939) was determined. Descriptors appeared in the model revealed that complexity, H-bond donor and lipophilic character are important parameters in describing the antioxidant activity. Apart from the compounds in the data set, we also designed 31 new antioxidant coumarin derivatives and predicted their antioxidant activity using the best two-descriptor model. Most of these compounds are promising antioxidants.

  13. Elucidation of the binding mechanism of coumarin derivatives with human serum albumin.

    Directory of Open Access Journals (Sweden)

    Archit Garg

    Full Text Available Coumarin is a benzopyrone which is widely used as an anti-coagulant, anti-oxidant, anti-cancer and also to cure arthritis, herpes, asthma and inflammation. Here, we studied the binding of synthesized coumarin derivatives with human serum albumin (HSA at physiological pH 7.2 by using fluorescence spectroscopy, circular dichroism spectroscopy, molecular docking and molecular dynamics simulation studies. By addition of coumarin derivatives to HSA the maximum fluorescence intensity was reduced due to quenching of intrinsic fluorescence upon binding of coumarin derivatives to HSA. The binding constant and free energy were found to be 1.957±0.01×10(5 M(-1, -7.175 Kcal M(-1 for coumarin derivative (CD enamide; 0.837±0.01×10(5 M(-1, -6.685 Kcal M(-1 for coumarin derivative (CD enoate, and 0.606±0.01×10(5 M(-1, -6.49 Kcal M(-1 for coumarin derivative methylprop (CDM enamide. The CD spectroscopy showed that the protein secondary structure was partially unfolded upon binding of coumarin derivatives. Further, the molecular docking studies showed that coumarin derivatives were binding to HSA at sub-domain IB with the hydrophobic interactions and also with hydrogen bond interactions. Additionally, the molecular dynamics simulations studies contributed in understanding the stability of protein-drug complex system in the aqueous solution and the conformational changes in HSA upon binding of coumarin derivatives. This study will provide insights into designing of the new inspired coumarin derivatives as therapeutic agents against many life threatening diseases.

  14. Evaluation of luminol chemiluminescence based on simultaneous introducing of coumarin derivatives as green fluorophores and chitosan-induced Au/Ag alloy nanoparticle as catalyst for the sensitive determination of glucose.

    Science.gov (United States)

    Chaichi, M J; Alijanpour, S O; Asghari, S; Shadlou, S

    2015-03-01

    We report herein the development of a novel chemiluminescence system based on simultaneous introducing of synthetic coumarin derivatives and chitosan-induced Au/Ag alloy NPs on the luminol CL system and suggest how it may be useful for determination of glucose. Chitosan-induced Au/Ag nanoalloys in the coumarin derivatives intensified-luminol CL system, in addition to catalyze CL reaction can make a change in the process of coumarin derivatives effect as fluorophore on the luminol CL system. This phenomenon is caused by interaction between active functional groups of coumarin derivatives and chitosan. The interaction strength depends on the coumarin derivatives' structure and their substituents. Considering the inevitable trend luminol radical and superoxide anion radical to absorption on the surface of the embedded Au/Ag nanoalloy in the chitosan matrix, it can be concluded that chitosan acts as a platform for all reagents involved in the CL reaction including coumarin derivatives, Au/Ag nanoalloy and luminol, and electron-transfer taking place on it; Placing all chemiluminescent reagents together on the chitosan network can lead to a powerful CL due to increasing rigidity of CL system. The most efficient coumarin derivative on the Au/Ag nanoalloy-fluorophore-luminol-H2O2 CL system, in relation to interaction capability with chitosan' functional groups, was selected and the CL condition in presence of it was optimized. Whereas the glucose oxidase-mediated oxidation of glucose yields gluconic acid and H2O2, under optimum condition the most efficient CL system was applied to detection of glucose due to enzymatically production of hydrogen peroxide. The linear response range of 1.5 × 10(-6)-5.0 × 10(-3) M and the detection limit (defined as the concentration that could be detected at the signal-to-noise ratio of 3) of 7.5 × 10(-7) M was found for the glucose standards. Also, the developed method was successfully applied to determination of glucose in

  15. Rhodium Catalyzed Decarbonylation

    DEFF Research Database (Denmark)

    Garcia Suárez, Eduardo José; Kahr, Klara; Riisager, Anders

    2017-01-01

    Rhodium catalyzed decarbonylation has developed significantly over the last 50 years and resulted in a wide range of reported catalyst systems and reaction protocols. Besides experimental data, literature also includes mechanistic studies incorporating Hammett methods, analysis of kinetic isotope...... effects as well as computational studies of model systems, which give an indication of the scope of the process. In this chapter, fundamental applications of Rh-catalyzed decarbonylation reactions are surveyed and discussed, including cross-coupling reactions, tandem reactions, and alternative...

  16. Genotype-guided coumarin dosing: Where are we now and where do we need to go next?

    NARCIS (Netherlands)

    Baranova, Ekaterina V.; Verhoef, Talitha I; Asselbergs, Folkert W.; De Boer, Anthonius; Maitland-Van Der Zee, Anke-Hilse

    2015-01-01

    Introduction: A large proportion of the coumarin dose variability is explained by environmental factors and by common genetic variants in the VKORC1 and CYP2C9 genes. Genotype-guided coumarin dosing has been proposed for a more accurate prediction of the coumarin dose in order to reduce the

  17. Relationship between coumarin-induced hepatocellular toxicity and mitochondrial function in rats.

    Science.gov (United States)

    Tanaka, Yasuhiro; Fujii, Wataru; Hori, Hisako; Kitagawa, Yoshinori; Ozaki, Kiyokazu

    2016-04-01

    The manifestation of coumarin-induced hepatocellular toxicity may differ and depends on the frequency of administration to rats. A single coumarin dose induces hepatocellular necrosis while repeated doses induce only hepatocyte degeneration. However, the mechanism underlying these effects remains unclear. Therefore, we investigated the mechanism of coumarin-induced hepatotoxicity in rats. Coumarin was administered to male rats as a single dose or for 4 consecutive days, and samples were obtained 4 or 24 h after a single dose or 24 h after the repeated doses. A single coumarin dose significantly induced hepatocellular necrosis in rats; however, toxicity was attenuated after repeated dosing. With a single dose, hepatocellular necrosis was preceded by increased mitochondrial number and size and decreased mitochondrial function. An increased expression of granular cytochrome P450 (CYP) 2E1 protein was observed in the cytoplasm and mitochondria of coumarin-treated rats compared to the expression in the untreated controls. Nevertheless, repeated dosing showed mitochondrial function that was equivalent to that of the control while enlarged CYP2E1 protein droplets were distributed outside the mitochondria. These results suggest that mitochondrial function and CYP2E1 expression might be involved in coumarin-induced hepatocellular toxicity in rats. A reduction in mitochondrial CYP2E1 might be implicated in the acquisition of coumarin resistance after repeated doses. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Mito-methyl coumarin, a novel mitochondria-targeted drug with great antitumor potential was synthesized.

    Science.gov (United States)

    Wang, Huanan; Xu, Wenqing

    2017-07-15

    Due to higher transmembrane potential of tumor cells, enhanced accumulation of cationic drugs in tumor mitochondria has been attributed to a higher (more negative inside) mitochondrial transmembrane potential compared with normal cells, emerging researchers are focus on developing mitochondria-targeted antitumor drugs. Coumarins showed great potential on antitumor, but mitochondria-targeted coumarin derivatives have not been reported. In the present study, we synthesized mitochondria-targeted-methyl coumarin (mito-methyl coumarin) through coupling 6-methyl coumarin to TPP. We confirmed that mito-methyl coumarin inhibited HeLa cells proliferation selectively, induced ROS generation, reduced mitochondrial membrane potential, promoted mitochondria Ca 2+ accumulation, decreased mitochondria mass and induced HeLa cells apoptosis, but methyl coumarin did not. These results demonstrate that we succeed in synthesizing a novel mitochondria-targeted drug, mito-methyl coumarin, which is effective in inhibiting HeLa cells proliferation and inducing HeLa cells apoptosis through promoting ROS generation and mitochondria Ca 2+ accumulation. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Coumarins from Murraya paniculata var. zollingeri endemic to the Timor Islands.

    Science.gov (United States)

    Teshima, Naoko; Yamada, Hiromi; Ju-ichi, Motoharu; Uji, Tahan; Kinoshita, Takeshi; Ito, Chihiro

    2015-02-01

    Four new coumarins, murrangatin-1'-senecioate (1), 5-methoxypanial (2), mexoticin-2'-senecioate (3) and murralongic acid (4), were isolated from the leaves of Murraya paniculata var. zollingeri, together with 23 known coumarins. The structures of the new compounds were elucidated based on spectroscopic data. The taxonomic status of M. paniculata var. zollingeri is briefly discussed, along with its similarity to M. paniculata.

  20. Arginine increases the solubility of coumarin: comparison with salting-in and salting-out additives.

    Science.gov (United States)

    Hirano, Atsushi; Arakawa, Tsutomu; Shiraki, Kentaro

    2008-09-01

    Poor aqueous solubility of low molecular weight drug substances hampers their development as pharmacological agents. Here, we have examined the effects of arginine on the solubility of organic compounds, coumarin, caffeine and benzyl alcohol, in aqueous solution. Arginine increased the solubility of aromatic coumarin, but not non-aromatic caffeine, concentration dependently, suggesting the favourable interaction of arginine with the aromatic structure. Consistent with this, arginine also increased the solubility of aromatic benzyl alcohol. Guanidine hydrochloride, urea and salting-in salts increased both coumarin and caffeine solubilities, while salting-out salts decreased them. These results suggest the specific interaction of arginine with aromatic groups, leading to increased solubility of coumarin. However, the effect of 1 M arginine on coumarin solubility was at most approximately 2-fold, which may limit its applications as a solubility enhancing agent.

  1. Synthesis and characterization of tunable coumarin- linked glasses as new class of organic/inorganic phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Luridiana, Alberto; Pretta, Gianluca; Secci, Francesco; Frongia, Angelo [Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, Complesso universitario di Monserrato, SS 554, bivio per Sestu, Monserrato (Canada) (Italy); Chiriu, Daniele; Carbonaro, Carlo Maria; Corpino, Riccardo [Dipartimento di Fisica, Università degli Studi di Cagliari, Complesso universitario di Monserrato, SS 554, bivio per Sestu, Monserrato (Canada) (Italy); Ricci, Pier Carlo, E-mail: carlo.ricci@dsf.unica.it [Dipartimento di Fisica, Universitá degli Studi di Cagliari, S.P. Monserrato-Sestu Km 0,700, 09042 Monserrato (Canada) (Italy)

    2014-10-21

    It is well known that stilbene with a trans conformation is highly fluorescent. From the viewpoint of molecular structure, coumarins bear a carbon-carbon double bond which is fixed as trans conformation as in trans-stilbene through a lactone structure. This can help to avoid the trans-cis transformation of the double bond under ultraviolet (UV) irradiation as observed in stilbene compounds and results in strong fluorescence and high fluorescence quantum yield and photostability in most of coumarin derivatives. Herein we report some preliminary results about the synthesis and spectroscopic characterization of tunable coumarins and the development of a new linkage protocol for the obtainment of monolayer coumarin-covalently linked glasses. The resulting organic/inorganic coumarin/silica based Self-Assembled Monolayer (SMA) film is proposed as new phosphors for the substituting of critical raw materials, like rare earths, in photonics applications.

  2. HPLC quantification of coumarin in bastard balm (Melittis melissophyllum L., Lamiaceae).

    Science.gov (United States)

    Maggi, F; Barboni, L; Caprioli, G; Papa, F; Ricciutelli, M; Sagratini, G; Vittori, S

    2011-12-01

    Coumarin occurs in many plants used as flavoring and is known to possess hepatotoxic effects. Despite in the EFSA 'Compendium of botanicals containing toxic substances' coumarin is reported to be present in Melittis melissophyllum (bastard balm), a plant traditionally used as beverage in Italy and Serbia, to the best of our knowledge quantitative data has never been reported. Thus, the amount of coumarin in bastard balm leaves and its variation during the annual phenological cycle were determined. The subsp. melissophyllum resulted to contain high levels of coumarin (14,392 mg/kg), mainly in the early stages of the plant cycle, suggesting prudence in its use as beverage. Furthermore, coumarin was found to be useful as marker compound to differentiate the bastard balm subspecies occurring in Italy, since the subsp. albida contained a much lower content of this molecule (19-34 mg/kg). Copyright © 2011 Elsevier B.V. All rights reserved.

  3. Muon catalyzed fusion

    Energy Technology Data Exchange (ETDEWEB)

    Ishida, K. [Advanced Meson Science Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Nagamine, K. [Muon Science Laboratory, IMSS-KEK, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Matsuzaki, T. [Advanced Meson Science Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Kawamura, N. [Muon Science Laboratory, IMSS-KEK, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)

    2005-12-15

    The latest progress of muon catalyzed fusion study at the RIKEN-RAL muon facility (and partly at TRIUMF) is reported. The topics covered are magnetic field effect, muon transfer to {sup 3}He in solid D/T and ortho-para effect in dd{mu} formation.

  4. Micropatterned coumarin polyester thin films direct neurite orientation.

    Science.gov (United States)

    McCormick, Aleesha M; Maddipatla, Murthy V S N; Shi, Shuojia; Chamsaz, Elaheh A; Yokoyama, Hiroshi; Joy, Abraham; Leipzig, Nic D

    2014-11-26

    Guidance and migration of cells in the nervous system is imperative for proper development, maturation, and regeneration. In the peripheral nervous system (PNS), it is challenging for axons to bridge critical-sized injury defects to achieve repair and the central nervous system (CNS) has a very limited ability to regenerate after injury because of its innate injury response. The photoreactivity of the coumarin polyester used in this study enables efficient micropatterning using a custom digital micromirror device (DMD) and has been previously shown to be biodegradable, making these thin films ideal for cell guidance substrates with potential for future in vivo applications. With DMD, we fabricated coumarin polyester thin films into 10×20 μm and 15×50 μm micropatterns with depths ranging from 15 to 20 nm to enhance nervous system cell alignment. Adult primary neurons, oligodendrocytes, and astrocytes were isolated from rat brain tissue and seeded onto the polymer surfaces. After 24 h, cell type and neurite alignment were analyzed using phase contrast and fluorescence imaging. There was a significant difference (pdistribution for both emergence angle (from the body of the cell) and orientation angle (at the tip of the growth cone) confirming alignment on patterned surfaces compared to control substrates (unpatterned polymer and glass surfaces). The expected frequency distribution for parallel alignment (≤15°) is 14% and the two micropatterned groups ranged from 42 to 49% alignment for emergence and orientation angle measurements, where the control groups range from 12 to 22% for parallel alignment. Despite depths being 15 to 20 nm, cell processes could sense these topographical changes and preferred to align to certain features of the micropatterns like the plateau/channel interface. As a result this initial study in utilizing these new DMD micropatterned coumarin polyester thin films has proven beneficial as an axon guidance platform for future nervous system

  5. Synthesis and Evaluation of Some Coumarin Containing Potential Antimicrobial Agents

    Directory of Open Access Journals (Sweden)

    Sayali D. Kudale

    2012-01-01

    Full Text Available A series of the Schiff’s bases incorporating coumarin and chalcone moeities, 3-(4-(4-(substituted phenylprop-1-ene-3-one phenylimino methyl-4-chloro-2h-chromen-2-one 4(a-g were synthesized as potential antimicrobial agents. These compounds were characterized on the basis of their spectral (IR, 1H NMR data and evaluated for antimicrobial activity in vitro against gram positive and gram negative bacteria and fungi. Compound 4b was found to be most active with an MIC of 20 µg/mL against all the tested organisms.

  6. Intramural esophagic hematoma secondary to coumarinic anticoagulation: a case report

    Science.gov (United States)

    2009-01-01

    Esophagic Intramural Hematoma is an uncommon clinical condition, with a prognosis which is essentially benign. On most cases, a predisposing or precipitating factor may be seen, with the most common ones being the history of esophagic instrumentation, food impactations and thrombocytopenia. In the following manuscript, the authors present the case of a 54-years-old male with history of valve replacement surgery, who was treated at the Clinica Cardiovascular (Medellin, Colombia), with a clinical case of Intramural Esophagic Hematoma that was later confirmed to be due to a Coumarinic overanticoagulation. On this case, it is evidenced that Intramural Esophagic Hematoma is an unrecognized complication of Courmarinic anticoagulation therapy. PMID:20069068

  7. Antiplatelet Aggregation Coumarins from the Leaves of Murraya omphalocarpa

    Directory of Open Access Journals (Sweden)

    Yang-Chang Wu

    2008-01-01

    Full Text Available Using a bioactivity-guided fractionation method, two coumarins: minumicrolineacetonide (1 and epimurpaniculol senecioate (2, were isolated from the leaves ofMurraya omphalocarpa Hayata (Rutaceae. Compound 1 had been previously synthesizedand was now isolated from natural sources for the first time, and compound 2, possessing anegative optical rotation value, is new. The structures and their stereochemistry were fullyelucidated on the basis of spectroscopic and X-ray crystallographic techniques. Bothcompounds 1 and 2 are active in the antiplatelet aggregation assay. Interestingly, thepossible acetonide artifact 1 displayed significant antiplatelet aggregation induced not onlyby AA and collagen but also by platelet activating factor (PAF.

  8. Bioactive Coumarins from the Stems of Clausena emarginata.

    Science.gov (United States)

    Ouyang, Guo-Qing; Li, Chuang-Jun; Yang, Jing-Zhi; Li, Li; Song, Xiu-Yun; Jiang, Yi-Na; Chen, Nai-Hong; Ma, Jie; Zhang, Dong-Ming

    2016-09-01

    Five new coumarins, clauemarmarins I - M (1 - 4), together with 10 known analogs (5 - 14), were isolated from the stems of Clausena emarginata. Compounds 8 - 13 were obtained from this plant for the first time. Their structures were established and elucidated by comprehensive analysis of spectroscopic data. The absolute configurations of 1 - 4 were further determined by their electronic circular dichroism spectroscopy. Compounds 5, 7, 12, and 14 exhibited inhibitory effects on LPS-induced NO production. Compounds 5 - 7 showed selective neuroprotective effects in Aβ25 - 35 model at 10 μm. © 2016 Wiley-VHCA AG, Zürich.

  9. Flavonoids and coumarins from Hieracium pilosella L. (Asteraceae

    Directory of Open Access Journals (Sweden)

    Tadeusz Krzaczek

    2011-01-01

    Full Text Available Typical chromatographic methods were successfully applied to isolate nine flavonoid compounds and two coumarin glycosides from the inflorescences and the herb of Hieracium pilosella L. Repeated column chromatography, occasionally paper chromatography and recrystallization made the separation of three flavonoid aglycones and six glycosides - possible. Coumarin glycosides were isolated by preparative thin layer chromatography. Subsequent UV, NMR and MS analyses have led to identification of the following flavonoid derivatives: known for the species - apigenin, luteolin, luteolin 7-O- ß-glucopyranoside, luteolin 4’-O-ß-glucopyranoside, isoetin 7-O-ß- -glucopyranoside, isoetin 4’-O-ß-glucuronide and new for the species – kaempferol 3-methyl ether and apigenin 7-O-ß-glucopyranoside. Third isoetin glycoside contained two different sugar moieties: xylose and glucose, probably attached to the hydroxyl groups at C-4’ or C-4’ and C-2’(or 5’ of an aglycone. Umbelliferone 7-O-ß-glucopyranoside (skimmin and new for the genus Hieracium esculetin 7-O-ß-glucopyranoside (cichoriin were determined by NMR and MS methods.

  10. Aurapten, a coumarin with growth inhibition against Leishmania major promastigotes

    Directory of Open Access Journals (Sweden)

    Napolitano H.B.

    2004-01-01

    Full Text Available Several natural compounds have been identified for the treatment of leishmaniasis. Among them are some alkaloids, chalcones, lactones, tetralones, and saponins. The new compound reported here, 7-geranyloxycoumarin, called aurapten, belongs to the chemical class of the coumarins and has a molecular weight of 298.37. The compund was extracted from the Rutaceae species Esenbeckia febrifuga and was purified from a hexane extract starting from 407.7 g of dried leaves and followed by four silica gel chromatographic fractionation steps using different solvents as the mobile phase. The resulting compound (47 mg of shows significant growth inhibition with an LD50 of 30 µM against the tropical parasite Leishmania major, which causes severe clinical manifestations in humans and is endemic in the tropical and subtropical regions. In the present study, we investigated the atomic structure of aurapten in order to determine the existence of common structural motifs that might be related to other coumarins and potentially to other identified inhibitors of Leishmania growth and viability. This compound has a comparable inhibitory activity of other isolated molecules. The aurapten is a planar molecule constituted of an aromatic system with electron delocalization. A hydrophobic side chain consisting of ten carbon atoms with two double bonds and negative density has been identified and may be relevant for further compound synthesis.

  11. Antileishmanial activity of furoquinolines and coumarins from Helietta apiculata.

    Science.gov (United States)

    Ferreira, Maria Elena; de Arias, Antonieta Rojas; Yaluff, Gloria; de Bilbao, Ninfa Vera; Nakayama, Hector; Torres, Susana; Schinini, Alicia; Guy, Isabelle; Heinzen, Horacio; Fournet, Alain

    2010-04-01

    The bark infusion of H. apiculata are used to treat wound healing related to cutaneous leishmaniasis and as anti-inflammatory. To isolate, purify active constituents of H. apiculata stem bark, and evaluate their in vitro and in vivo antileishmanial activities. Isolation by chromatographic methods and chemical identification of furoquinoline alkaloids and coumarins, then evaluation of the in vitro leishmanicidal activity of these compounds against three strains of Leishmania sp. promastigotes and in vivo against Leishmania amazonensis in Balb/c mice. Furoquinoline alkaloids and coumarins presented a moderate in vitro activity against promastigote forms of Leishmania sp. with IC(50) values in the range between 17 and >50 microg/ml. Balb/c mice infected with Leishmania amazonensis were treated with gamma-fagarine by oral route, or with 3-(1'-dimethylallyl)-decursinol or (-)-heliettin by subscutaneous route for 14 days at 10mg/kg daily. In these conditions, gamma-fagarine, 3-(1'-dimethylallyl)-decursinol and (-)-heliettin showed the same efficacy as the reference drug reducing by 97.4, 95.6 and 98.6% the parasite loads in the lesion, respectively. These compounds showed significant efficacy in L. amazonensis infected mice, providing important knowledge to improve its potential role for a future use in the treatment of cutaneous leishmaniasis. Copyright 2009 Elsevier GmbH. All rights reserved.

  12. Prenylated coumarins: natural phosphodiesterase-4 inhibitors from Toddalia asiatica.

    Science.gov (United States)

    Lin, Ting-Ting; Huang, Yi-You; Tang, Gui-Hua; Cheng, Zhong-Bin; Liu, Xin; Luo, Hai-Bin; Yin, Sheng

    2014-04-25

    Bioassay-guided fractionation of the ethanolic extract of the roots of Toddalia asiatica led to the isolation of seven new prenylated coumarins (1-7) and 14 known analogues (8-21). The structures of 1-7 were elucidated by spectroscopic analysis, and their absolute configurations were determined by combined chemical methods and chiral separation analysis. Compounds 1-5, named toddalin A, 3‴-O-demethyltoddalin A, and toddalins B-D, represent an unusual group of phenylpropenoic acid-coupled prenylated coumarins. Compounds 1-21 and four modified analogues, 10a, 11a, 13a, and 17a, were screened by using tritium-labeled adenosine 3',5'-cyclic monophosphate ([3H]-cAMP) as substrate for their inhibitory activity against phosphodiesterase-4 (PDE4), which is a drug target for the treatment of asthma and chronic obstructive pulmonary disease. Compounds 3, 8, 10, 10a, 11, 11a, 12, 13, 17, and 21 exhibited inhibition with IC50 values less than 10 μM. Toddacoumalone (8), the most active compound (IC50=0.14 μM), was more active than the positive control, rolipram (IC50=0.59 μM). In addition, the structure-activity relationship and possible inhibitory mechanism of the active compounds are also discussed.

  13. Vasorelaxing activity of two coumarins from Murraya paniculata leaves.

    Science.gov (United States)

    Cuong, Nguyen Manh; Khanh, Pham Ngoc; Duc, Ho Viet; Huong, Tran Thu; Tai, Bui Huu; Binh, Nguyen Quoc; Durante, Miriam; Fusi, Fabio

    2014-01-01

    In the search for novel chemical scaffolds leading to potential antihypertensive agents, the methanol extract of Murraya paniculata leaves was assessed for its effects on isolated rat aorta rings. The vasorelaxing effect of the chloroform fraction of the methanol plant extract was the most potent for its vasorelaxing activity on rat aorta rings contracted by 60 mM K(+) (K60). Two coumarins were isolated from the chloroform fraction: the novel kimcuongin (1) and the known murracarpin (2). Their structures were determined from spectroscopic evidences including (1)H- and (13)C-NMR, correlation spectroscopy (COSY), nuclear Overhauser effect spectroscopy (NOESY), heteronuclear multiple bond correlation (HMBC), heteronuclear single quantum correlation (HSQC), and high resolution mass spectrometry (HR-MS). Kimcuongin and, to a lesser extent, murracarpin, showed vasorelaxing activity with IC50 values of 37.7 µM and 139.3 µM, respectively. The coumarins kimcuongin and murracarpin may thus represent a novel class of vasodilators of natural source.

  14. Catalyzing alignment processes

    DEFF Research Database (Denmark)

    Lauridsen, Erik Hagelskjær; Jørgensen, Ulrik

    2004-01-01

    This paper describes how environmental management systems (EMS) spur the circulation of processes that support the constitution of environmental issues as specific environ¬mental objects and objectives. EMS catalyzes alignmentprocesses that produce coherence among the different elements involved...... time and in combination with other social processes establish more aligned and standardized environmental performance between countries. However, examples of the introduction of environmental management suggests that EMS’ only plays a minor role in developing the actual environmental objectives...

  15. A comparison of US and Norwegian regulation of coumarin in tobacco products.

    Science.gov (United States)

    Givel, M

    2003-12-01

    This paper examines policy processes regarding why the USA and Norway have not regulated coumarin in tobacco. A qualitative analysis of all tobacco industry documents regarding coumarin since the 1950s from the 1998 US Master Settlement Agreement and subsequent legal settlements. Additional data were collected from newspaper reports, general internet search engines, journal articles, scholarly reports, court cases, statutes, regulations, and informal correspondence with tobacco control experts in Norway. An overview, summary, and analysis of all documents related to coumarin. In the USA from 1954 until 1985 when coumarin was reportedly removed from domestic cigarettes, but not from pipe tobacco until 1996, and not at all from imported Indian bidi cigarettes, regulatory efforts were stymied. In Norway, from 1973 to the present, the tobacco industry has never disclosed whether its tobacco products contain coumarin. In both the USA and Norway, the extreme delay and lack of vigorous evidence gathering and significant remedies were caused by tobacco industry assertions that revealing tobacco additives was a violation of trade secrets, and by weak regulatory authority and efforts to regulate coumarin. Vigorous and expeditious regulatory investigations and remedies for harmful additives in tobacco, such as coumarin, can protect the public health. Astute insider and outsider political advocacy by health advocates is required to hold elected officials and civil servants publicly accountable for failing to enact disclosure laws and to engage in effective regulatory efforts.

  16. Arabidopsis Transporter ABCG37/PDR9 contributes primarily highly oxygenated Coumarins to Root Exudation.

    Science.gov (United States)

    Ziegler, Jörg; Schmidt, Stephan; Strehmel, Nadine; Scheel, Dierk; Abel, Steffen

    2017-06-16

    The chemical composition of root exudates strongly impacts the interactions of plants with microorganisms in the rhizosphere and the efficiency of nutrient acquisition. Exudation of metabolites is in part mediated by ATP-binding cassette (ABC) transporters. In order to assess the contribution of individual ABC transporters to root exudation, we performed an LC-MS based non-targeted metabolite profiling of semi-polar metabolites accumulating in root exudates of Arabidopsis thaliana plants and mutants deficient in the expression of ABCG36 (PDR8/PEN3), ABCG37 (PDR9) or both transporters. Comparison of the metabolite profiles indicated distinct roles for each ABC transporter in root exudation. Thymidine exudation could be attributed to ABCG36 function, whereas coumarin exudation was strongly reduced only in ABCG37 deficient plants. However, coumarin exudation was compromised in abcg37 mutants only with respect to certain metabolites of this substance class. The specificity of ABCG37 for individual coumarins was further verified by a targeted LC-MS based coumarin profiling method. The response to iron deficiency, which is known to strongly induce coumarin exudation, was also investigated. In either treatment, the distribution of individual coumarins between roots and exudates in the investigated genotypes suggested the involvement of ABCG37 in the exudation specifically of highly oxygenated rather than monohydroxylated coumarins.

  17. The Use of Coumarins as Environmentally-Sensitive Fluorescent Probes of Heterogeneous Inclusion Systems

    Directory of Open Access Journals (Sweden)

    Brian D. Wagner

    2009-01-01

    Full Text Available Coumarins, as a family of molecules, exhibit a wide range of fluorescence emission properties. In many cases, this fluorescence is extremely sensitive to the local environment of the molecule, especially the local polarity and microviscosity. In addition, coumarins show a wide range of size, shape, and hydrophobicity. These properties make them especially useful as fluorescent probes of heterogeneous environments, such as supramolecular host cavities, micelles, polymers and solids. This article will review the use of coumarins to probe such heterogeneous systems using fluorescence spectroscopy.

  18. Synthesis and Antimicrobial Activity of 4-Substituted 1,2,3-Triazole-Coumarin Derivatives

    Directory of Open Access Journals (Sweden)

    Priscila López-Rojas

    2018-01-01

    Full Text Available A new series of coumarin-1,2,3-triazole conjugates with varied alkyl, phenyl and heterocycle moieties at C-4 of the triazole nucleus were synthesized using a copper(I-catalysed Huisgen 1,3-dipolar cycloaddition reaction of corresponding O-propargylated coumarin (3 or N-propargylated coumarin (6 with alkyl or aryl azides. Based on their minimal inhibitory concentrations (MICs against selected microorganisms, six out of twenty-six compounds showed significant antibacterial activity towards Enterococcus faecalis (MIC = 12.5–50 µg/mL. Moreover, the synthesized triazoles show relatively low toxicity against human erythrocytes.

  19. The effect of acids on fluorescence of coumarin-6 in organic solvents

    Science.gov (United States)

    Mina, M. V.; Puzyk, I. P.; Puzyk, M. V.

    2013-02-01

    The effect of acids (HCl, HClO4, HNO3, and CH3COOH) on the fluorescence of coumarin-6 in organic solvents (acetonitrile, acetone, butanol-1, and ethanol) is studied. The regions of acid (HCl, HClO4, HNO3) concentrations that lead to a change in the fluorescence spectra are determined for each of the solvents. It is shown that, for all the solvents studied, acetic acid with a concentration within the region 10-1-10-6 M causes no significant changes in the fluorescence spectrum of coumarin-6. A mechanism of the coumarin-6 protonation is proposed.

  20. Risk assessment of coumarin using the bench mark dose (BMD) approach: children in Norway which regularly eat oatmeal porridge with cinnamon may exceed the TDI for coumarin with several folds.

    Science.gov (United States)

    Fotland, T Ø; Paulsen, J E; Sanner, T; Alexander, J; Husøy, T

    2012-03-01

    Coumarin is a naturally occurring flavouring substance in cinnamon and many other plants. It is known that coumarin can cause liver toxicity in several species, and it is considered a non-genotoxic carcinogen in rodents. By using the bench mark dose approach we re-assessed coumarin toxicity and established a new TDI for coumarin of 0.07 mg/kg bw/day. Oral intake of coumarin is related to consumption of cinnamon-containing foods and food supplements. Cinnamon is a widely used spice in Norway, and can be used as topping on oatmeal porridge. Based on analyses of coumarin in Norwegian foods, intake calculations for children and adults were conducted, and a risk assessment of coumarin in the Norwegian population was performed. Intake estimates of coumarin show that small children eating oatmeal porridge several times a week sprinkled with cinnamon could have a coumarin intake of 1.63 mg/kg bw/day and may exceeding the TDI with several folds. Adults drinking cinnamon-based tea and consuming cinnamon supplements also can exceed TDI. The coumarin intake could exceed the TDI by 7- to 20-fold in some intake scenarios. Such large daily exceedances of TDI, even for a limited time period of 1-2 weeks, cause concern of adverse health effects. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. Catalyzed Ceramic Burner Material

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, Amy S., Dr.

    2012-06-29

    Catalyzed combustion offers the advantages of increased fuel efficiency, decreased emissions (both NOx and CO), and an expanded operating range. These performance improvements are related to the ability of the catalyst to stabilize a flame at or within the burner media and to combust fuel at much lower temperatures. This technology has a diverse set of applications in industrial and commercial heating, including boilers for the paper, food and chemical industries. However, wide spread adoption of catalyzed combustion has been limited by the high cost of precious metals needed for the catalyst materials. The primary objective of this project was the development of an innovative catalyzed burner media for commercial and small industrial boiler applications that drastically reduce the unit cost of the catalyzed media without sacrificing the benefits associated with catalyzed combustion. The scope of this program was to identify both the optimum substrate material as well as the best performing catalyst construction to meet or exceed industry standards for durability, cost, energy efficiency, and emissions. It was anticipated that commercial implementation of this technology would result in significant energy savings and reduced emissions. Based on demonstrated achievements, there is a potential to reduce NOx emissions by 40,000 TPY and natural gas consumption by 8.9 TBtu in industries that heavily utilize natural gas for process heating. These industries include food manufacturing, polymer processing, and pulp and paper manufacturing. Initial evaluation of commercial solutions and upcoming EPA regulations suggests that small to midsized boilers in industrial and commercial markets could possibly see the greatest benefit from this technology. While out of scope for the current program, an extension of this technology could also be applied to catalytic oxidation for volatile organic compounds (VOCs). Considerable progress has been made over the course of the grant

  2. Assessment of Coumarin Levels in Ground Cinnamon Available in the Czech Retail Market

    Science.gov (United States)

    Blahová, Jana; Svobodová, Zdeňka

    2012-01-01

    The objective of this study was to determine the coumarin content of ground cinnamon purchased from retail markets in the Czech Republic. No sample was labelled with information on the botanical source, but, in some cases, the countries of origin were specified. For comparison, a single cinnamon sample imported directly from a plantation in Sri Lanka that came from Cinnamomum verum was analyzed. Results from 60 ground cinnamon samples comprising twelve brands confirmed a high content of coumarin, with mean levels ranging from 2 650 to 7 017 mg · kg−1. The high coumarin content confirmed that these cinnamon samples obtained from cassia cinnamon were in contrast to the sample from Sri Lanka, which was coumarin-free. PMID:22761548

  3. Assessment of Coumarin Levels in Ground Cinnamon Available in the Czech Retail Market

    Directory of Open Access Journals (Sweden)

    Jana Blahová

    2012-01-01

    Full Text Available The objective of this study was to determine the coumarin content of ground cinnamon purchased from retail markets in the Czech Republic. No sample was labelled with information on the botanical source, but, in some cases, the countries of origin were specified. For comparison, a single cinnamon sample imported directly from a plantation in Sri Lanka that came from Cinnamomum verum was analyzed. Results from 60 ground cinnamon samples comprising twelve brands confirmed a high content of coumarin, with mean levels ranging from 2 650 to 7 017 mg · kg−1. The high coumarin content confirmed that these cinnamon samples obtained from cassia cinnamon were in contrast to the sample from Sri Lanka, which was coumarin-free.

  4. Rare Coumarins Induce Apoptosis, G1 Cell Block and Reduce RNA Content in HL60 Cells

    Directory of Open Access Journals (Sweden)

    Widelski Jarosław

    2017-02-01

    Full Text Available The rare coumarins stenocarpin, stenocarpin isobutyrate, oficinalin, oficinalin isobutyrate, 8-methoxypeucedanin and the known xanthotoxin, isoimperatorin, bergapten, peucedanin and 8–methoxyisoimperatorin were isolated from Peucedanum luxurians Tamamsch. (Apiaceae and identified by means of spectral data (1D and 2D NMR. Their immunomodulating activity was evaluated by flow cytometry and their influence on HL60 cells as well as on PHA-stimulated PBLs was tested. All tested coumarins induce apoptosis (maximal in the 48 h culture and decrease cell proliferation in a time- and dose-dependent manner, especially in HL60 cells. They also induce partial G1 block, but only in HL60 cells (at 100 µM concentrations. Dose-dependent reduction of RNA content was also found in G1 cells treated by the coumarins. All of the tested coumarins also possessed immunomodulatory activities. Bergapten and xanthotoxin were found to be the best candidates for further evaluation as anti-cancer drugs.

  5. Release profile of synthesized coumarin derivatives as a novel antibacterial agent from glass ionomer cement (GIC)

    Science.gov (United States)

    Rahman, Fatimah Suhaily Abdul; Osman, Hasnah; Mohamad, Dasmawati

    2017-12-01

    Glass ionomer cements (GIC) are widely used as dental restorative materials due to their aesthetics features and fluoride content. However, a capability of fluoride content in GIC to inhibit bacteria growth in an oral environment was insufficient for a long term which may lead to secondary caries. Therefore, two types of synthesized coumarin derivatives were incorporated with GIC to act as new antibacterial agent. However prior to the antibacterial evaluation, this study investigated the release profile of GIC incorporated with 3-Acetylcoumarin (GIC-1) and hydrazinyl thiosemicarbazide of coumarin derivatives (GIC-2) at three different concentrations of 0.5, 1.0 and 1.5 wt% up to 30 days. At early incubation period, GIC-1 revealed a higher release profile at 0.5 % fabrication that reached almost 45 % of cumulative release for 8 hours observational. Meanwhile, a slightly different output was obtained for GIC-2 in which 1.0 % fabrication of coumarin gave a better release in the initial hour. However, the pattern was replaced by 0.5 % substitution after 4 hours incubation time. A substitution of 1.5 % coumarin seems to be low in releasing activity for all materials. Conversely, in a longer period 1.0 % fabrication was discovered to be the highest coumarin release among others fabrications for both materials. Filler particle size and porosity of the materials were considered to be the main factor that may affect the coumarin release. Nonetheless, both synthesized coumarin derivatives can be incorporated with GIC as their release profile look very promising. Ultimately, the coumarin derivatives could improve the properties of GIC.

  6. Evaluation of coumarin derivatives as anti-fungal agents against soil-borne fungal pathogens.

    Science.gov (United States)

    Brooker, N L; Kuzimichev, Y; Laas, J; Pavlis, R

    2007-01-01

    Development of new and safer pesticides that are target-specific is backed by a strong Federal, public and commercial mandate. In order to generate a new generation of pesticides that are more ecologically friendly and safe, natural products are being evaluated for pesticidal activities. Many plant-derived chemicals have proven pesticidal properties, including compounds like sesamol (3,4-Methylenedioxyphenol), a lipid from sesame oil and coumarins (1,2-Benzopyrone) found in a variety of plants such as clover, sweet woodruff and grasses. Both of these plant-derived compounds have been shown to inhibit a range of fungi and bacteria and it is believed that these cyclic compounds behave as natural pesticidal defense molecules for plants. These compounds represent a starting point for the exploration of new derivative compounds possessing a range of antifungal activity and for use as seed protectants. Within this study, six derivatives of coumarin that resembled sesamol's structure were screened for their antifungal activity against a range of soil-bome plant pathogenic fungi. Fungi in this in vitro screen included Macrophomina phaseolina (causal agent of charcoal rot) and Pythium spp. (causal agent of seedling blight), two phylogenetically diverse and economically important plant pathogens. Preliminary studies indicate that many of these novel coumarin derivatives work very effectively in vitro to inhibit fungal growth and several coumarin derivatives have higher antifungal activity and stability as compared to either the original coumarin or sesamol compounds alone. Interestingly, several of these highly active coumarin derivatives are halogenated compounds with solubility in water, and they are relatively easy and inexpensive to synthesize. These halogenated coumarin derivatives remained active for extended periods of time displaying 100% inhibition of fungal growth for greater than 3 weeks in vitro. In addition to the in vitro fungal inhibition assays, preliminary

  7. Synthesis and Anticancer Activity of Some New Derivatives of Coumarin and Quinolinyl Mercaptotriazoles

    Directory of Open Access Journals (Sweden)

    Mona A. Hosny

    2012-01-01

    Full Text Available Pechmann condensation of ethylacetoacetate with derivatives of phenol by heating in absence of solvent and with montmorillonite clays K-10 afforded coumarin derivatives (1a-e in good yields which on reaction with thiosemicarbazide in anhydrous pyridine yielded coumarin-quinolinyl mercaptotriazole (2a-e. The latter compounds were evaluated for their antimicrobial and anticancer activities. The newly synthesized compounds were characterized by IR, 1HNMR and mass spectra.

  8. In vitro antifungal activity of coumarin extracted from Loeselia mexicana Brand.

    Science.gov (United States)

    Navarro-García, Victor M; Rojas, Gabriela; Avilés, Margarita; Fuentes, Macrina; Zepeda, Gerardo

    2011-09-01

    The bis-coumarin daphnoretin and its monomeric precursors scopoletin and umbelliferone were isolated for the first time from the aerial part of Loeselia mexicana Brand (a vegetal species used in Mexican traditional medicine) using chromatographic techniques. The structures of these compounds were determined by (1) H and (13) C NMR analyses. These coumarins were evaluated for in vitro antifungal activity. The three compounds tested showed significant antifungal activity. © 2011 Blackwell Verlag GmbH.

  9. Femtosecond study of laser coloring soluble in water: the coumarins; Etude femtoseconde de colorants laser solubles dans l`eau: les coumarines

    Energy Technology Data Exchange (ETDEWEB)

    Cassara, L.

    1996-11-29

    This thesis concerns the study of four hydro soluble coumarins A.T.C., D.M.A.T.C., D.A.T.C. et C.H.O.S., analogues of classical coumarins C120, C311, C1 and C102. These molecules are made hydro soluble because of the substitution in position 4- of the methyl group by a polyether group. The mechanisms of deactivation are studied because of fluorescence methods (resolved in time and transient absorption) which allow to study the reactional dynamics of coumarins after luminous excitement. SEveral time scales, from a few femto seconds to the nanosecond have been approachable and have allowed investigations on different processes: relaxation S{sub n} {yields} S{sub 1}, solvation dynamics, orientational diffusion of the solution and deactivation process S{sub 1} {yields} S{sub 0} of radiative and non radiative relaxation in different solvents. (N.C.)

  10. A novel method for the synthesis of coumarin laser dyes derived from 3-(1H-benzoimidazol-2-yl coumarin-2-one under microwave irradiation

    Directory of Open Access Journals (Sweden)

    Ghasem Bakhtiari

    2014-12-01

    Full Text Available We want to achieve the synthesis of 3-(1H-benzoimidazol-2-yl-7-(diethylamino coumarin-2-one (1, 3-(1H-benzoimidazol-2-yl-7-(dimethylamino coumarin-2-one (2, 3-(1H-benzoimidazol-2-yl coumarin-2-one (3 that are important dyes in industries (Soko owska et al., 2001. Methods for the synthesis of some of these compounds have been the title in some pervious patents, but enough information about separation and purification of them was not clearly indicated. We carried out several methods for the synthesis of the mentioned compound and purification with different yields. Now, we can synthesise these dyes under microwave irradiation in solid phase and solvent free methods with 80% yield, which is a high and remarkable percentage.

  11. Coumarin- and Carboxyl-Functionalized Supramolecular Polybenzoxazines Form Miscible Blends with Polyvinylpyrrolidone

    Directory of Open Access Journals (Sweden)

    Ruey-Chorng Lin

    2017-04-01

    Full Text Available In this study, we synthesized a novel multifunctional benzoxazine monomer (Coumarin-COOH BZ, possessing both coumarin and COOH groups, through the reaction of 4-methyl-7-hydroxycoumarin, 4-aminobenzoic acid, and paraformaldehyde in 1,4-dioxane, with the structure confirmed using 1H and 13C nuclear magnetic resonance and Fourier transform infrared (FTIR spectroscopy. Differential scanning calorimetry (DSC, FTIR spectroscopy, and thermogravimetric analysis were then employed to monitor the thermal curing behavior of Coumarin-COOH BZ and its blends with poly(N-vinyl-2-pyrrolidone (PVP, both before and after photodimerization of the coumarin moieties. DSC revealed a single glass transition temperature for each Coumarin-COOH BZ/PVP blend composition; a large positive deviation based on the Kwei equation suggested that strong hydrogen bonding existed between the Coumarin-COOH BZ and PVP segments, confirmed through FTIR spectroscopic analyses. The thermal properties improved (i.e., increased glass transition and thermal degradation temperatures as a result of the increased crosslinking density after photodimerization under UV exposure.

  12. UV Fluorescent Epoxy Adhesives from Noncovalent and Covalent Incorporation of Coumarin Dyes.

    Science.gov (United States)

    McFadden, Peter D; Frederick, Kevin; Argüello, Liliana A; Zhang, Yizheng; Vandiver, Pamela; Odegaard, Nancy; Loy, Douglas A

    2017-03-22

    Epoxies are commonly used in art conservation as adhesives for artifact reconstruction and repair. However, with the development of colorless epoxies, it has become more difficult to detect repair work. Fluorescent epoxies would allow for easy detection of the epoxy joints by simple visual inspection under UV light while remaining unnoticeable under normal display lighting. Coumarins are natural dyes that can be added in very small amounts to make thermosets fluoresce. Depending on the functionality of the coumarin used, the dye may be physically encapsulated in the cross-linked polymer or it may be bound to the polymer through covalent bonds. In this paper, we examine the efficacy of coumarin (1) and coumarin 480 (2) as physically encapsulated dyes and 7-hydroxycoumarin (3) and 7-glycidyloxycoumarin (4) as covalently bound dyes in a commercial epoxy thermoset, Epo-Tek 301. All four dyes could be used to make the epoxy fluorescent, but coumarins 1 and 2 slightly reduced the lap shear strength of the thermoset and could be extracted with solvent. In contrast, coumarins 3 and 4 had little effect on the mechanical properties of the epoxy and only minute amounts could be extracted.

  13. Effect of matrix treatment on spectroscopic properties of HCl catalysed sol-gel glasses containing coumarin laser dyes.

    Science.gov (United States)

    Deshpande, Aparna V; Jathar, Laxman V; Rane, Jayraj R

    2009-07-01

    Coumarin 1, Coumarin 2 and Coumarin 120 are embedded in transparent sol-gel glass samples prepared by sol-gel process using dip method. The sol-gel matrix is given dip treatment with Methanol /Distilled Water (50/50 vol) for 1 to 16 h before dipping into dye solution. The effect of dipping time of matrix in Methanol/ Distilled Water on spectroscopic properties of coumarin dye doped glass samples has been studied. The Optical Density (OD) at absorption maximum wavelength and Fluorescence Intensity (FI) at fluorescence maximum wavelength of all coumarin dyes increase with the time of dipping of the sol-gel sample. These absorption/fluorescence properties of coumarin dyes in sol-gel glass matrices are compared with its respective properties in methanolic solution in acidic environment. The cause of these changes in OD/FI with dipping time is discussed by taking into account the absorption / fluorescence of dye in acidified methanol.

  14. Coumarin enhances nitrate uptake in maize roots throughout a modulation of plasma membrane H+ -ATPase activity.

    Science.gov (United States)

    Lupini, Antonio; Araniti, Fabrizio; Mauceri, Antonio; Princi, Maria Polsia; Sorgonà, Agostino; Sunseri, Francesco; Varanini, Zeno; Abenavoli, Maria Rosa

    2017-11-27

    1.Coumarin is one of the simplest plant secondary metabolite widely distributed in plant kingdom affecting root form and function, including anatomy, morphology and nutrient uptake. Although, some plant responses to coumarin have been described, comprehensive knowledge of the physiological and molecular mechanisms is lacking. 2.Maize seedlings exposed to different coumarin concentrations, alone or in combination with 200 μM nitrate (NO3- ), were analyzed, through a physiological and molecular approach, to elucidate action of coumarin on net NO3- uptake rate (NNUR). In detail, the time course of NNUR, plasma membrane (PM) H+ -ATPase activity, the proton pumping, and related gene expressions (ZmNPF6.3, ZmNRT2.1, ZmNAR2.1, ZmHA3 and ZmHA4) were evaluated. 3.Coumarin alone did not affect nitrate uptake, the PM H+ -ATPase activity as well as the transcript levels of ZmNRT2.1 and ZmHA3. By contrast, coumarin alone increased ZmNPF6.3, ZmNAR2.1 and ZmHA4 expression, as observed in response to abiotic stress. When coumarin and NO3- were concurrently added to the nutrient solution, a significant increase in the NNUR, PM H+ -ATPase activity together with ZmNAR2.1:ZmNRT2.1 and ZmHA4 expressions were observed, suggesting that coumarin affected the inducible component of high affinity transport system (iHATS), and this effect appeared to be mediated by nitrate. Moreover, the results with vanadate, an inhibitor of the PM H+ -ATPase, suggested that this enzyme could be a main target of coumarin. 4.Surprisingly, coumarin did not affect the PM H+ -ATPase activity by direct contact with plasma membrane vesicle isolated from maize roots, indicating its possible elicitor role in the gene transcription. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  15. [Mechanism of the antiasthmatic effect of total coumarins in the fruit of Cnidium monnieri (L.)Cuss].

    Science.gov (United States)

    Chen, Z; Duan, X

    1990-05-01

    Total coumarins in the fruit of Cnidium monnieri show a marked protective effect against bronchial asthma induced by inhalation of histamine in conscious guinea pig. In vitro these total coumarins can relax the contraction of the isolated trachea in guinea pigs induced by histamine as well as increase the perfusion rate of isolated lung preparation of guinea pig. These actions, however, may be blocked by propranolol. Besides, these coumarins cannot increase the heart rate and arterial blood pressure in anesthetized rats. All this shows that the antiasthmatic effect of total coumarins in the fruit of Cnidium monnieri is mediated by beta 2-receptor.

  16. Effects of Different Coumarin- 3-Carboxamide Agents on Scopolamine Induced Learning and Memory Deficit in Mice

    Directory of Open Access Journals (Sweden)

    Samaneh Ghanei Nasab

    2017-06-01

    Full Text Available Introduction: It has been shown that three new synthetic coumarins-3-carboxamides including 3-fluorobenzilchloride, 4-fluorobenzilchloride and 2-hidroxy-3 metoxybenzaldehyde, have acetylcholinesterase inhibitory activity. This study was performed to estimate ameliorating effect of these new coumarin-3-carboxamides on memory impairments induced by scopolamine (1 mg/kg, induced prolongation in mice. Methods: 30 male mice were divided into five groups, 6 mice in each group. Three experiment groups received coumarins-3- carboxamides (10 mg/kg body weight 30 min before scopalamin injection and two other groups considered as normal (saline-treated groups and finally one negative control (scopalamin only group. The experiment groups were treated with coumarins of 3-fluorobenzilchloride, 4-fluorobenzilchloride and 2-hidroxy-3 metoxybenzaldehyde. The passive avoidance test was performed in an automatic conventional shuttle box set-up. The stepped down latency and number of errors was recorded. Results: With reference to saline-treated group, scopolamine-treated mice demonstrated impairment of learning and memory as a reduction of latency and an increased numbers of errors in step-down testp < 0.01. Treated mice receiving these coumarins at the dose of 10 mg/kg showed an increase in the number of avoidances on the memory tests compared to the scopolamine group (p < 0.01. Conclusion: The study has demonstrated some therapeutic effects of coumarin-3-carboxamides on learning and memory deficit induced by scopolamine. Further investigation is needed to explore whether coumarin-3-carboxamides could be beneficial for memory impairment in Alzheimer’s disease in which cholinergic deficit is one of the hallmarks. 

  17. Cytotoxic cardiac glycosides and coumarins from Antiaris toxicaria.

    Science.gov (United States)

    Shi, Li-Shian; Kuo, Sheng-Chu; Sun, Han-Dong; Morris-Natschke, Susan L; Lee, Kuo-Hsiung; Wu, Tian-Shung

    2014-03-15

    Eight new cardiac glycosides/aglycones (antiaritoxiosides A-G, 1-7, and antiarotoxinin B, 8), two new coumarins (anticarins A-B, 41-42), and two new flavanones (antiarones L-K, 43-44) were isolated from trunk bark of Antiaris toxicaria together with 53 known compounds. The new structures were established by extensive analysis of spectroscopic data. Compound 1 (10-carboxy and 3α-hydroxy) and compounds 3-6 (10-hydroxy) contain unique substituents that are rarely found in cardiac glycosides. The cytotoxic effects of isolated compounds against ten human cancer cell lines, KB, KB-VIN, A549, MCF-7, U-87-MG, PC-3, 1A9, CAKI-1, HCT-9 and S-KMEL-2, were tested using the sulforhodamine B assay. Five compounds (12, 16, 20, 22, and 31) showed significant cytotoxicity against all ten cancer cell lines, with notable potency at the ng/mL level against some cell lines, which merits further development as clinical trial candidates. Copyright © 2014. Published by Elsevier Ltd.

  18. The Relation between Hepatotoxicity and the Total Coumarin Intake from Traditional Japanese Medicines Containing Cinnamon Bark

    Science.gov (United States)

    Iwata, Naohiro; Kainuma, Mosaburo; Kobayashi, Daisuke; Kubota, Toshio; Sugawara, Naoko; Uchida, Aiko; Ozono, Sahoko; Yamamuro, Yuki; Furusyo, Norihiro; Ueda, Koso; Tahara, Eiichi; Shimazoe, Takao

    2016-01-01

    Cinnamon bark is commonly used in traditional Japanese herbal medicines (Kampo medicines). The coumarin contained in cinnamon is known to be hepatotoxic, and a tolerable daily intake (TDI) of 0.1 mg/kg/day, has been quantified and used in Europe to insure safety. Risk assessments for hepatotoxicity by the cinnamon contained in foods have been reported. However, no such assessment of cinnamon bark has been reported and the coumarin content of Kampo medicines derived from cinnamon bark is not yet known. To assess the risk for hepatotoxicity by Kampo medicines, we evaluated the daily coumarin intake of patients who were prescribed Kampo medicines and investigated the relation between hepatotoxicity and the coumarin intake. The clinical data of 129 outpatients (18 male and 111 female, median age 58 years) who had been prescribed keishibukuryogankayokuinin (TJ-125) between April 2008 and March 2013 was retrospectively investigated. Concurrent Kampo medicines and liver function were also surveyed. In addition to TJ-125, the patients took some of the other 32 Kampo preparations and 22 decoctions that include cinnamon bark. The coumarin content of these Kampo medicines was determined by high performance liquid chromatography (HPLC). TJ-125 had the highest daily content of coumarin (5.63 mg/day), calculated from the daily cinnamon bark dosage reported in the information leaflet inserted in each package of Kampo medicine. The coumarin content in 1g cinnamon bark decoction was 3.0 mg. The daily coumarin intake of the patients was 0.113 (0.049–0.541) mg/kg/day, with 98 patients (76.0%) exceeding the TDI. Twenty-three patients had an abnormal change in liver function test value, but no significant difference was found in the incidence of abnormal change between the group consuming less than the TDI value (6/31, 19.4%) and the group consuming equal to or greater than the TDI value (17/98, 17.3%). In addition, no abnormal change related to cinnamon bark was found for individual

  19. Coumarins as Potential Inhibitors of DNA Polymerases and Reverse Transcriptases. Searching New Antiretroviral and Antitumoral Drugs.

    Science.gov (United States)

    Garro, Hugo A; Pungitore, Carlos R

    2015-01-01

    Human Immunodeficiency Virus (HIV) is the viral agent of Acquired Immunodeficiency Syndrome (AIDS), and at present, there is no effective vaccine against HIV. Reverse Transcriptase (RT) is an essential enzyme for retroviral replication, such as HIV as well as for other RNA infectious viruses like Human T lymphocyte virus. Polymerases act in DNA metabolism, modulating different processes like mitosis, damage repair, transcription and replication. It has been widely documented that DNA Polymerases and Reverse Transcriptases serve as molecular targets for antiviral and antitumoral chemotherapy. Coumarins are oxygen heterocycles that are widely distributed throughout the plant kingdom. Natural coumarins have attraction due to their bioactive properties such as tumor promotion inhibitory effects, and anti-HIV activity. Coumarins and derivates exhibit potent inhibitory effects on HIV-1 replication in lymphocytes and compounds isolated from Calophyllum inophyllum or DCK derivates showed inhibitory activity against human RT. Furthermore, natural isocoumarins isolated from cultures of fungi or hydroxycoumarins were able to inhibit human DNA polymerase. In view of their importance as drugs and biologically active natural products, and their medicinally useful properties, extensive studies have been carried out on the synthesis of coumarin compounds in recent years. Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs), a class of antiretroviral chemotherapeutic agents, act by binding to an allosteric pocket showing, generally, low toxicity. This work tries to summarize the investigation about natural and synthetic coumarins with the ability to inhibit key enzymes that play a crucial role in DNA metabolism and their possible application as antiretroviral and antitumoral agents.

  20. A prodrug approach to the use of coumarins as potential therapeutics for superficial mycoses.

    Directory of Open Access Journals (Sweden)

    Derry K Mercer

    Full Text Available Superficial mycoses are fungal infections of the outer layers of the skin, hair and nails that affect 20-25% of the world's population, with increasing incidence. Treatment of superficial mycoses, predominantly caused by dermatophytes, is by topical and/or oral regimens. New therapeutic options with improved efficacy and/or safety profiles are desirable. There is renewed interest in natural product-based antimicrobials as alternatives to conventional treatments, including the treatment of superficial mycoses. We investigated the potential of coumarins as dermatophyte-specific antifungal agents and describe for the first time their potential utility as topical antifungals for superficial mycoses using a prodrug approach. Here we demonstrate that an inactive coumarin glycone, esculin, is hydrolysed to the antifungal coumarin aglycone, esculetin by dermatophytes. Esculin is hydrolysed to esculetin β-glucosidases. We demonstrate that β-glucosidases are produced by dermatophytes as well as members of the dermal microbiota, and that this activity is sufficient to hydrolyse esculin to esculetin with concomitant antifungal activity. A β-glucosidase inhibitor (conduritol B epoxide, inhibited antifungal activity by preventing esculin hydrolysis. Esculin demonstrates good aqueous solubility (<6 g/l and could be readily formulated and delivered topically as an inactive prodrug in a water-based gel or cream. This work demonstrates proof-of-principle for a therapeutic application of glycosylated coumarins as inactive prodrugs that could be converted to an active antifungal in situ. It is anticipated that this approach will be applicable to other coumarin glycones.

  1. Fluorescence Quenching of Two Coumarin-3-carboxylic Acids by Trivalent Lanthanide Ions.

    Science.gov (United States)

    Cisse, Lamine; Djande, Abdoulaye; Capo-Chichi, Martine; Delattre, François; Saba, Adama; Brochon, Jean-Claude; Sanouski, Serguei; Tine, Alphonse; Aaron, Jean-Jacques

    2017-03-01

    The effects of various trivalent lanthanide ions (acetates of Ce3+, Er3+, Eu3+, Nd3+) on the electronic absorption and fluorescence spectra of un-substituted coumarin-3-carboxylic acid (CCA) and 7-N,N-diethylamino-coumarin-3-carboxylic acid (DECCA) have been investigated in dimethylsulfoxide (DMSO) at room temperature. Depending on the lanthanide ion nature and concentration, significant spectral changes of absorption bands occurred for both coumarin derivatives. These spectral changes were attributed to the formation of ground-state complexes between the coumarin carboxylate derivatives and lanthanide ions. The fluorescence quenching of CCA and DECCA upon increasing the lanthanide ion concentration was studied. Different quantitative treatments, including the Stern-Volmer equation, the Perrin equation and a polynomial equation, were applied and compared in order to determine the nature of the quenching mechanisms for both coumarin derivatives. The results suggested the contribution of both dynamic and static quenching. Significant differences of CCA and DECCA fluorescence quenching efficiency were also observed, depending on the lanthanide ion. DECCA fluorescence lifetime measurements, performed in the absence and in the presence of Ln3+, confirmed a contribution of static quenching.

  2. Solvatochromic benzo[h] coumarins: Synthesis, solvatochromism, NLO and DFT study

    Science.gov (United States)

    Warde, Umesh; Sekar, Nagaiyan

    2017-10-01

    Three benzo[h] coumarins were synthesized and analyzed for their potential NLOphoric properties. Coumarins were synthesized using Knoevenagel condensation method by reacting hydroxyl-naphthalene aldehyde with cyano-methylelene-benzazoles containing NH, O and S elements respectively as the active methylene compounds. The absorption maxima for the coumarins are not affected by the solvent polarity but emission maxima does. Emission solvatochromism was analyzed using various solvent polarity functions which highlights the polarity dependency of the emission profile. Coumarins showed satisfactory values for first and second hyperpolarizability which are comparable using solvatochromism and DFT. NLO properties are also compared with the limits of hyperpolarizability calculated using sum rule of quantum mechanics. Results show that the NLO properties predicted by DFT are close to the upper limits of hyperpolarizability. The functional CAM-B3LYP is proven to be suitable for predicting NLO properties for these coumarins compared to functional B3LYP. The present study highlights the importance of such molecules for incorporating in advanced NLOphores.

  3. Harvest time influences on coumarin and umbelliferone contents in extracts of Justicia pectoralis Jacq. (tilo

    Directory of Open Access Journals (Sweden)

    Jorge Enrique Rodríguez Chanfrau

    Full Text Available Introduction: Justicia pectoralis Jacq. (Acanthaceae is medicinal plant species commonly used in Cuba for the treatment of nervous disorders because of its sedative effect. Coumarin is one of its main active phytochemicals present in the extracts obtained from this plant and used as analytic marker in quality control. On the other hand, this compound contributes to the sedative effect attributed to this plant. Objective: to evaluate the influence of harvest time on the coumarin and umbelliferone (7-hydroxycoumarin in Justicia pectoralis extracts. Methods: the experiment lasted two years. The harvest was performed at 4, 6 and 8 months after planting. Aqueous and hydroalcohol extracts were produced and the coumarin and umbelliferone contents were determined by high resolution liquid chromatography. Results: the achieved results showed the presence of coumarin and umbelliferone in both extracts. Both methods can be used for the extraction of these components from the plant, although in the case of umbelliferone, the best extraction results were achieved by using aqueous extract. In both cases, the recovery percentages were more than 98 %. This study confirmed that the harvest time significantly influences on the coumarin and umbelliferone contents. Conclusions: the best results are observed in the first two harvests (4 and 6 months at summer time, which indicates that the industry should process the vegetal material in these two periods of the year.

  4. Identification of coumarin as the sensitizer in a patient sensitive to her own perfume but negative to the fragrance mix

    DEFF Research Database (Denmark)

    Mutterer, V; Gimenéz-Arnau, Elena; Lepoittevin, J P

    1999-01-01

    obtained was afterwards tested on the patient using a ROAT and/or a patch test. Only 1 fraction gave a positive ROAT result. This fraction was analyzed and found to contain coumarin and ethyl vanillin. Coumarin, one of the most widely used fragrance compounds that is not present in the fragrance mix...

  5. Quantitative structure-toxicity relationship study of some natural and synthetic coumarins using retention parameters

    Directory of Open Access Journals (Sweden)

    Rabtti El Hadi M.A.

    2012-01-01

    Full Text Available Four lipophilicity descriptors (RM0, b, C0, PC1 for twelve coumarine derivatives were determined by reversed-phase thin-layer chromatography in order to analyze which descriptor best describes the lipophilicity of coumarines investigated. Moreover, possible chemical toxicity of coumarins, expressed as the probability of a compound to cause organ-specific health effects, was calculated using ACD/Tox Suite program. The quantitative relationships between toxicity and molecular descriptors, including experimentally determined lipophilicity descriptors obtained in current study, were investigated using partial least square regression. The best models were obtained for kidney and liver health effects. Quantitative structure-toxicity relationship models revealed the importance of electric polarization descriptors, size descriptors and lipophilicity descriptors. Obtained models were used for the selection of the structural features of the compounds that are significantly affecting their absorption, distribution, metabolism, excretion, and toxicity. [Acknowledgements. This work has been supported by the Ministry of Education and Science of Serbia, Grant 172017.

  6. Antifungal Activity of Coumarin from Ageratum conyzoides L. Leaves on Candida albicans cells

    Directory of Open Access Journals (Sweden)

    Gunawan Pamudji Widodo

    2012-07-01

    Full Text Available The aim of this study was to identify the antifungal activity of coumarin isolated from Ageratum conyzoides L. leaves and to observe its influence on Candida albicans cells by scanning electron microscope (SEM and transmission electron microscope (TEM. Antifungal activity testing by disk diffusion method showed coumarin was active toward pathogenic fungus, Candida albicans with the MIC value of coumarin of 125 g mL-1. The influence of this substance on C. albicans cells was observed by scanning and transmission electron microscopies. The result showed that this compound damaged the cell by pores formation on the cell wall. The death of cells occurred due to leakage and necrotic of cytoplasmic content.

  7. Two new coumarins from the bark of Streblus indicus (Bur.) Corner.

    Science.gov (United States)

    He, Ruijie; Deng, Shengping; Nie, Hui; Huang, Yan; Liu, Buming; Yang, Ruiyun; Huang, Shuai; Zhou, Dexiong; Chen, Huangcan; Li, Jun; Zhang, Yanjun

    2017-05-01

    Two new coumarins 7-O-(6-O-(5-O-3,4,5-tri-methoxycinnamate-β-d-apiofuranosyl-β-d-glucopyranosyl)-6-methoxy coumarin (1) and 7-O-(6-O-(4-(2-hydroxy-1-hydroxymethyl-ethoxy)-3-methoxy-cinnamyl)-β-d-glucopyranosyl)-6-methoxy coumarin (2), along with 10 known metabolites, were isolated from the bark of Streblus indicus, their structures were identified by comparison of experimental and published spectroscopic data. (S)-marmesinin (6) and scoparone (7) exhibited moderate antimicrobial activity in vitro against Staphylococcus aureus strain with the MIC values of 62.5 and 125.0 μg/mL, respectively. Betulinic acid showed inhibitory activity in vitro against MCF-7 cell with IC50 value of 9.5 ± 0.1 μM.

  8. Inhibitory activity of coumarins from Artemisia capillaris against advanced glycation endproduct formation.

    Science.gov (United States)

    Jung, Hyun Ah; Park, Jin Ju; Islam, Md Nurul; Jin, Seung Eun; Min, Byung-Sun; Lee, Je-Hyun; Sohn, Hee Sook; Choi, Jae Sue

    2012-06-01

    Since glycation can lead to the onset of diabetic complications due to chronic hyperglycemia, several indigenous Artemisia species were evaluated as potential inhibitors of advanced glycation endproducts (AGE). Among them, the Artemisia capillaris plant demonstrated the highest AGE inhibitory activity. Repeated column chromatography was performed to isolate a new acylated flavonoid glycoside, acacetin-7-O-(6″-O-acetyl)-β-D-glucopyranosyl-(1→2)[α-L-rhamnopyranosyl]-(1→6)-β-D-glucopyranoside, along with 11 known flavonoids (acacetin-7-O-β-D-glucopyranosyl-(1→2)[α-L-rhamnopyranosyl]-(1→6)-β-D-glucopyranoside, linarin, quercetin, hyperoside, isorhamnetin, isorhamnetin 3-galactoside, isorhamnetin 3-glucoside, isorhamnetin 3-arabinoside, isorhamnetin 3-robinobioside, arcapillin, and cirsilineol), six coumarins (umbelliferone, esculetin, scopoletin, scopolin, isoscopolin, and scoparone), and two phenolic derivatives (4,5-di-O-caffeoylquinic acid and chlorogenic acid). In determining the structure-activity relationship (SAR), it was found that the presence and position of hydroxyl group of test coumarins (coumarin, esculin, isoscopoletin, daphnetin, 4-methylcoumarin, and six isolated coumarins) may play a crucial role in AGE inhibition. A free hydroxyl group at C-7 and a glucosyl group instead of a methoxyl group at C-6 are two important parameters for the inhibitory potential of coumarins on AGE formation. A. capillaris and five key AGE inhibitors, including 4,5-di-Ocaffeoylquinic acid, umbelliferone, esculetin, esculin, and scopoletin, were identified as potential candidates for use as therapeutic or preventive agents for diabetic complications and oxidative stress-related diseases. We understand this to be the first detailed study on the SAR of coumarins in AGE inhibition.

  9. Coumarin Derivatives Solvent-Free Synthesis under Microwave Irradiation over Heterogeneous Solid Catalysts

    Directory of Open Access Journals (Sweden)

    Souad Bouasla

    2017-11-01

    Full Text Available A suitable methodology of synthesis of coumarin derivatives by Pechmann reaction over heterogeneous solid acid catalysts in a free solvent media under microwave irradiation is described. Resorcinol, phenol and ethyl acetoacetate were selected as model reactants in the Pechmann condensation. The catalytic activity of several materials—Amberlyst-15, zeolite β and sulfonic acid functionalized hybrid silica—in solvent-free microwave-assisted synthesis of the corresponding coumarin derivatives has been investigated in detail. 7-Hydroxy-4-methylcoumarin and 4-methylcoumarin were obtained in 97% and 43% yields, respectively, over Amberlyst-15. This was the most active catalyst in the Pechmann reaction under studied conditions.

  10. A coumarin-based fluorescent probe as a central nervous system disease biomarker.

    Science.gov (United States)

    Yap, Ann-Chee; Mahamad, Ummi Affah; Lim, Shen-Yang; Kim, Hae-Jo; Choo, Yeun-Mun

    2014-11-10

    Homocysteine and methylmalonic acid are important biomarkers for diseases associated with an impaired central nervous system (CNS). A new chemoassay utilizing coumarin-based fluorescent probe 1 to detect the levels of homocysteine is successfully implemented using Parkinson's disease (PD) patients' blood serum. In addition, a rapid identification of homocysteine and methylmalonic acid levels in blood serum of PD patients was also performed using the liquid chromatography-mass spectrometry (LC-MS). The results obtained from both analyses were in agreement. The new chemoassay utilizing coumarin-based fluorescent probe 1 offers a cost- and time-effective method to identify the biomarkers in CNS patients.

  11. One-pot four component synthesis of novel 3-furyl coumarin ...

    Indian Academy of Sciences (India)

    Efficient and facile synthesis of 3-furyl coumarin derivatives have been achieved by reaction of ... sensors.10 Coumarin analogs with furan heterocycle iso- ..... 117.8, 99.9, 86.9, 60.4, 52.6, 52.2, 51.1, 43.4, 29.8;. LCMS: MH. +. , 441. Anal. Calcd. For C23H26N2O7: C,. 62.43; H, 5.90; N, 6.35%. Found: C, 62.40; H, 5.95;.

  12. A Coumarin-Based Fluorescent Probe as a Central Nervous System Disease Biomarker

    Directory of Open Access Journals (Sweden)

    Ann-Chee Yap

    2014-11-01

    Full Text Available Homocysteine and methylmalonic acid are important biomarkers for diseases associated with an impaired central nervous system (CNS. A new chemoassay utilizing coumarin-based fluorescent probe 1 to detect the levels of homocysteine is successfully implemented using Parkinson’s disease (PD patients’ blood serum. In addition, a rapid identification of homocysteine and methylmalonic acid levels in blood serum of PD patients was also performed using the liquid chromatography-mass spectrometry (LC-MS. The results obtained from both analyses were in agreement. The new chemoassay utilizing coumarin-based fluorescent probe 1 offers a cost- and time-effective method to identify the biomarkers in CNS patients.

  13. Statement on the safety of glucosamine for patients receiving coumarin anticoagulants

    DEFF Research Database (Denmark)

    Tetens, Inge

    2011-01-01

    that showed in some patients being prescribed coumarin anticoagulants, especially warfarin, that the International Normalised Ratio (INR) increased after they began taking glucosamine, which indicated an increase in the coagulation time. In most cases the increased INR values were symptomless but in some...... cases haemorrhage occurred in a variety of organs, and in one case this resulted in a persistent vegetative state. The evidence for an interaction between glucosamine and coumarin anticoagulants is strengthened by the observation that in the majority of cases the INR began to fall to normal values when...

  14. Antifibrotic activity of coumarins from Cnidium monnieri fruits in HSC-T6 hepatic stellate cells.

    Science.gov (United States)

    Shin, Eunjin; Lee, Chul; Sung, Sang Hyun; Kim, Young Choong; Hwang, Bang Yeon; Lee, Mi Kyeong

    2011-04-01

    The CHCl(3) fraction of Cnidium monnieri fruits significantly inhibited the proliferation of hepatic stellate cells in an in-vitro assay system employing HSC-T6 hepatic stellate cell lines. Activity-guided fractionation of the CHCl(3) fraction of C. monnieri led to the isolation of ten coumarins: osthol (1), meranzin (2), auraptenol (3), meranzin hydrate (4), 7-hydroxy-8-methoxy coumarin (5), imperatorin (6), xanthotoxol (7), xanthotoxin (8), bergapten (9) and isopimpinellin (10). Of these, compounds 1 and 6 significantly inhibited proliferation of HSCs in a time- and concentration-dependent manner. In addition, compounds 1 and 6 significantly reduced collagen content in HSC-T6 cells.

  15. Valorisation des plantes médicinales à coumarines des marchés de ...

    African Journals Online (AJOL)

    Objectif : Une enquête ethnobotanique a été conduite en février 2014 auprès des vendeuses des marchés Est de la ville de Douala concernant les différents usages des plantes à coumarines. Résultats : Au total, 38 espèces végétales à coumarines dont 25 herbacées et 13 ligneuses ont été inventoriées. Parmi ces ...

  16. Cassia cinnamon as a source of coumarin in cinnamon-flavored food and food supplements in the United States.

    Science.gov (United States)

    Wang, Yan-Hong; Avula, Bharathi; Nanayakkara, N P Dhammika; Zhao, Jianping; Khan, Ikhlas A

    2013-05-08

    Coumarin as an additive or as a constituent of tonka beans or tonka extracts is banned from food in the United States due to its potentially adverse side effects. However, coumarin in food from other natural ingredients is not regulated. "True Cinnamon" refers to the dried inner bark of Cinnamomum verum. Other cinnamon species, C. cassia, C. loureiroi, and C. burmannii, commonly known as cassia, are also sold in the U.S. as cinnamon. In the present study, coumarin and other marker compounds were analyzed in authenticated cinnamon bark samples as well as locally bought cinnamon samples, cinnamon-flavored foods, and cinnamon-based food supplements using a validated UPLC-UV/MS method. The experimental results indicated that C. verum bark contained only traces of coumarin, whereas barks from all three cassia species, especially C. loureiroi and C. burmannii, contained substantial amounts of coumarin. These species could be potential sources of coumarin in cinnamon-flavored food in the U.S. Coumarin was detected in all locally bought cinnamon, cinnamon-flavored foods, and cinnamon food supplements. Their chemical profiles indicated that the cinnamon samples and the cinnamon in food supplements and flavored foods were probably Indonesian cassia, C. burmannii.

  17. Versatility of 7-Substituted Coumarin Molecules as Antimycobacterial Agents, Neuronal Enzyme Inhibitors and Neuroprotective Agents

    Directory of Open Access Journals (Sweden)

    Erika Kapp

    2017-09-01

    Full Text Available A medium-throughput screen using Mycobacterium tuberculosis H37Rv was employed to screen an in-house library of structurally diverse compounds for antimycobacterial activity. In this initial screen, eleven 7-substituted coumarin derivatives with confirmed monoamine oxidase-B and cholinesterase inhibitory activities, demonstrated growth inhibition of more than 50% at 50 µM. This prompted further exploration of all the 7-substituted coumarins in our library. Four compounds showed promising MIC99 values of 8.31–29.70 µM and 44.15–57.17 µM on M. tuberculosis H37Rv in independent assays using GAST-Fe and 7H9+OADC media, respectively. These compounds were found to bind to albumin, which may explain the variations in MIC between the two assays. Preliminary data showed that they were able to maintain their activity in fluoroquinolone resistant mycobacteria. Structure-activity relationships indicated that structural modification on position 4 and/or 7 of the coumarin scaffold could direct the selectivity towards either the inhibition of neuronal enzymes or the antimycobacterial effect. Moderate cytotoxicities were observed for these compounds and slight selectivity towards mycobacteria was indicated. Further neuroprotective assays showed significant neuroprotection for selected compounds irrespective of their neuronal enzyme inhibitory properties. These coumarin molecules are thus interesting lead compounds that may provide insight into the design of new antimicrobacterial and neuroprotective agents.

  18. One-pot four component synthesis of novel 3-furyl coumarin ...

    Indian Academy of Sciences (India)

    4-chloro-3-formyl coumarin; secondary amines; [3+2] cyclo addition; Multicomponent reaction; X-ray crystallography. ... derivatives have been achieved by reaction of 4-chloro-3-formylcoumarin, secondary amines, dialkyl acetylenedicarboxylates and diversely substituted isocyanides using four component, one-pot reaction.

  19. Gas phase ion chemistry of coumarins: ab initio calculations used to ...

    African Journals Online (AJOL)

    The gas phase ion chemistry of coumarins using electron ionization (EI), positive chemical ionization (PCI) and negative chemical ionization (NCI) in a time of flight and quadrupole mass spectrometer (qMS) coupled to a gas chromatograph is outlined. The observations in NCI mode were complimented with Ab initio ...

  20. Neurological outcome in school-age children after in utero exposure to coumarins

    NARCIS (Netherlands)

    Wesseling, J; Van Driel, D; Smrkovsky, M; Van der Veer, E; Geven-Boere, LM; Sauer, PJJ; Touwen, BCL

    The effect of prenatal exposure to coumarins (acenocoumarol, phenprocoumon) on neurological outcome was assessed in a cohort of 306 children aged 7-15 years. Findings were compared with those in a non-exposed cohort of 267 children, matched for sex, age, and demographic region. We used a

  1. Coumarins during Pregnancy: Long-term Effects on Growth and Development of School-age Children

    NARCIS (Netherlands)

    Wesseling, J; Van Driel, D; Heymans, HSA; Rosendaal, FR; Geven-Boere, LM; Smrkovsky, M; Touwen, BCL; Sauer, PJJ; Van der Veer, E

    Anticoagulation during pregnancy is complicated because of potential risks for mother and foetus. Unfractionated or low-molecular-weight heparin is used for most anticoagulant indications. Its efficacy, however, in pregnant women with prosthetic heart valves is questioned, therefore coumarins are

  2. Planar chromatographic screening and quantification of coumarin in food, confirmed by mass spectrometry.

    Science.gov (United States)

    Krüger, Stephanie; Winheim, Luisa; Morlock, Gertrud E

    2018-01-15

    A sensitive quantitative screening of coumarin in 43 commercially available cinnamons and cinnamon-containing foods was developed via HPTLC. Complex samples like cinnamon, tea, breakfast cereals, milk rice, jam, cinnamon stars and buns were extracted with methanol only. Separation was performed on silica gel with a mixture of n-hexane, ethyl acetate and ammonia. The specific detection via derivatization with an ethanolic potassium hydroxide solution resulted in fluorescent coumarin zones, measured at 365/>400nm after stabilization. Limits of detection and quantification were 200 and 400pg/band, respectively. Over all different sample types, the contents ranged from 0.3 to 5129mg/kg with a mean repeatability and mean intermediate precision of 4% each. HPTLC-MS of selected zones, eluted via the TLC-MS Interface into MS, confirmed the identity of coumarin. Effect-directed detection as bioanalytical tool for risk assessment showed coumarin to be active against Aliivibrio fischeri bacteria down to 100ng/band. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Allosteric Partial Inhibition of Monomeric Proteases. Sulfated Coumarins Induce Regulation, not just Inhibition, of Thrombin

    Science.gov (United States)

    Verespy III, Stephen; Mehta, Akul Y.; Afosah, Daniel; Al-Horani, Rami A.; Desai, Umesh R.

    2016-01-01

    Allosteric partial inhibition of soluble, monomeric proteases can offer major regulatory advantages, but remains a concept on paper to date; although it has been routinely documented for receptors and oligomeric proteins. Thrombin, a key protease of the coagulation cascade, displays significant conformational plasticity, which presents an attractive opportunity to discover small molecule probes that induce sub-maximal allosteric inhibition. We synthesized a focused library of some 36 sulfated coumarins to discover two agents that display sub-maximal efficacy (~50%), high potency (thrombin (>150-fold). Michaelis-Menten, competitive inhibition, and site-directed mutagenesis studies identified exosite 2 as the site of binding for the most potent sulfated coumarin. Stern-Volmer quenching of active site-labeled fluorophore suggested that the allosteric regulators induce intermediate structural changes in the active site as compared to those that display ~80–100% efficacy. Antithrombin inactivation of thrombin was impaired in the presence of the sulfated coumarins suggesting that allosteric partial inhibition arises from catalytic dysfunction of the active site. Overall, sulfated coumarins represent first-in-class, sub-maximal inhibitors of thrombin. The probes establish the concept of allosteric partial inhibition of soluble, monomeric proteins. This concept may lead to a new class of anticoagulants that are completely devoid of bleeding. PMID:27053426

  4. Synthetic Mono/di-halogenated Coumarin Derivatives and Their Anticancer Properties.

    Science.gov (United States)

    Kasumbwe, Kabange; Venugopala, Katharigatta N; Mohanlall, Viresh; Odhav, Bharti

    2017-01-01

    Coumarins are naturally occurring plant metabolites and several synthetic coumarin analogues are known for their various pharmacological properties such as anticoagulant, antimicrobial, anticancer, antioxidant, anti-inflammatory and antiviral properties. Objective; Keeping this promising pharmacological properties in mind, in the present investigation, mono/dihalogenated coumarin analogues CMRN1-CMRN7 have been synthesized and evaluated for their anticancer activity. The cytotoxicity potential of the test compounds was evaluated against UACC-62, MCF-7 and PBM (Peripheral Blood Mononuclear) cell lines using MTT assay. The apoptotic potential of the coumarin compounds was evaluated against UACC-62 cell by assessing membrane change, mitochondria membrane potential, pro-apoptotic changes were investigated using the AnnexinV-PI staining, JC-1, caspase-3 enzyme kits respectively on flow cytometer. The test compounds CMRN1, CMRN2, CMRN4 and CMRN5 have strongly suppressed the cell proliferation of UACC-62 and MCF-7 cancer cell lines. Furthermore the test compounds CMRN1, CMRN2, CMRN4 and CMRN5 exerted antiproliferative effects through apoptosis induction against UACC-62. Compounds CMRN1, CMRN2, CMRN4 and CMRN5 can be considered as lead compounds to arrive at a promising anticancer agents.

  5. LATE NEUROLOGICAL, COGNITIVE AND BEHAVIORAL SEQUELAE OF PRENATAL EXPOSURE TO COUMARINS - A PILOT-STUDY

    NARCIS (Netherlands)

    OLTHOF, E; DEVRIES, TW; TOUWEN, BCL; SMRKOVSKY, M; GEVENBOERE, LM; HEIJMANS, HSA; VANDERVEER, E

    Neurological, cognitive and behavioural development were assessed in a group of 21, 8- to 10-year old children whose mothers took coumarins during pregnancy. Findings were compared with those in a group of 17 control children. The study was performed to test whether it is feasible to carry out a

  6. The effect of high pressure on the luminescent properties of coumarin 153

    CERN Document Server

    Li Hong; He Li Ming; Wu Shi Kang; Li Yi; Yang Guo Qiang

    2002-01-01

    A dual-fluorescence emitting behaviour of coumarin 153 powder has been detected at high pressure while at ambient pressure the dye exhibits only single-band emission. Because of the strong electron-withdrawal group at site 7, these two fluorescent peaks can be ascribed to local excited state emission and charge transfer state emission, respectively.

  7. Antileishmanial activity of prenylated coumarins isolated from Ferulago angulata and Prangos asperula

    Science.gov (United States)

    Sajjadi, Seyed Ebrahim; Eskandarian, Abbas-Ali; Shokoohinia, Yalda; Yousefi, Hosein-Ali; Mansourian, Marjan; Asgarian-Nasab, Hasan; Mohseni, Negar

    2016-01-01

    Leishmaniasis has a wide spectrum of signs and symptoms due to infection to numbers of Leishmania species and makes enormous mortality and morbidity. There are clues of antileishmanial effects of prenylated coumarins. Apiaceae family is one of the most important sources of coumarins. Air-dried aerial parts of Ferulago angulata and fruits of Prangos asperula were extracted with n-hexane, using a soxhlet apparatus. The solvents were evaporated under reduced pressure. Column chromatography and crystallization process resulted to isolation of three prenylated coumarins. 1H-nuclear magnetic resonance, electron ionization Mass and Infrared spectra were used for elucidation of isolated compounds. Leishmanicidal activity of isolated coumarins was assessed on Leishmania major strain (MRHO/IR/75/ER) for the first time. Suberosin epoxide and suberosin were isolated from aerial parts of F. angulata and osthol was extracted from grounded fruits of P. asperula. Osthol showed a significant antileishmanial effect on promastigotes in early hours of exposure with IC50 of 14.40 µg/mL but suberosin epoxide showed only a weak antileishmanial activity. IC50 of osthol and suberosin epoxide after 48 h were 10.79 and 54.0 µg/mL, respectively. Suberosin showed no remarkable effect in these concentrations. This is the first report on the pharmacological activity of suberosin epoxide. Substantial difference between efficacies of two isomers, osthol and suberosin remarks the importance of prenyl substituent location on C-8. PMID:27651813

  8. Anticoagulant activity of isolated coumarins (suberosin and suberenol) and toxicity evaluation of Ferulago carduchorum in rats.

    Science.gov (United States)

    Golfakhrabadi, Fereshteh; Abdollahi, Mohammad; Ardakani, Mohammad Reza Shams; Saeidnia, Soodabeh; Akbarzadeh, Tahmineh; Ahmadabadi, Amir Nili; Ebrahimi, Azin; Yousefbeyk, Fatemeh; Hassanzadeh, Alireza; Khanavi, Mahnaz

    2014-10-01

    Ferulago carduchorum Boiss. & Hausskn. (Apiaceae) is known as Chavil in Persian which grows in west of Iran. Local people add Chavil to dairy and oil ghee as a natural preservative to extend the expiration date. The goal of this survey is the safety evaluation of the total extract of F. carduchorum in rats by determining both oral acute and subchronic toxicities; furthermore, the anticoagulant activity of isolated coumarins was evaluated. The aerial parts of F. carduchorum were extracted by the percolation method. The anticoagulant activity of isolated coumarins was evaluated and the total extract was used to investigate acute and subchronic toxicity in rats. In the subchronic toxicity model, doses of 250, 500, and 1000 mg/kg of the extract were administered to treated groups for 30 consecutive days by gavage. According to the results of acute toxicity, the LD50 of Chavil extract was more than 2000 mg/kg. The subchronic study showed no significant difference (p > 0.05) between the groups treated with extract and control groups in hematological (erythrocyte, total and differential leukocyte, hematocrit, hemoglobin, platelet count) and biochemical parameter (glucose, albumin, cholesterol, triglycerides, aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase) evaluations. The isolated coumarins (suberosin and suberenol) prolonged the prothrombin time (PT) at doses of 3 and 6 mg/kg compared with control (p coumarins showed anticoagulant effect in rats.

  9. Coumarins in horse chestnut flowers: isolation and quantification by UPLC method.

    Science.gov (United States)

    Dudek-Makuch, Marlena; Matławska, Irena

    2013-01-01

    The coumarins: scopoletin, esculetin and fraxetin were isolated from the flowers of horse chestnut (Aesculus hippocastanum L., Hippocastanaceae) and identified by spectrophotometric methods (UV, 1H, 13C NMR, ESI-MS). Their content, determined using the Ultra Performance Liquid Chromatography (UPLC), was 0.41, 0.13 and 0.05%, respectively.

  10. Iodine-Catalyzed Polysaccharide Esterification

    Science.gov (United States)

    A review is provided of the recent reports to use iodine-catalyzed esterification reaction to produce esters from polysaccharides. The process entails reaction of the polysaccharide with an acid anhydride in the presence of a catalytic level of iodine, and in the absence of additional solvents. T...

  11. Coumarins from the Herb Cnidium monnieri and chemically modified derivatives as antifoulants against Balanus albicostatus and Bugula neritina larvae

    National Research Council Canada - National Science Library

    Wang, Zhan-Chang; Feng, Dan-Qing; Ke, Cai-Huan

    2013-01-01

    In the search for new environmental friendly antifouling (AF) agents, four coumarins were isolated from the herbal plant Cnidium monnieri, known as osthole (1), imperatorin (2), isopimpinellin (3) and auraptenol (4...

  12. Coumarins from the Herb Cnidium monnieri and Chemically Modified Derivatives as Antifoulants against Balanus albicostatus and Bugula neritina Larvae

    OpenAIRE

    Zhan-Chang Wang; Dan-Qing Feng; Cai-Huan Ke

    2013-01-01

    In the search for new environmental friendly antifouling (AF) agents, four coumarins were isolated from the herbal plant Cnidium monnieri, known as osthole (1), imperatorin (2), isopimpinellin (3) and auraptenol (4). Furthermore, five coumarin derivatives, namely 8-epoxypentylcoumarin (5), meranzin hydrate (6), 2'-deoxymetranzin hydrate (7), 8-methylbutenalcoumarin (8), and micromarin-F (9) were synthesized from osthole. Compounds 1, 2, 4, 7 showed high inhibitory activities against larv...

  13. Comparison of seven structurally related coumarins on the inhibition of Quorum sensing of Pseudomonas aeruginosa and Chromobacterium violaceum.

    Science.gov (United States)

    D'Almeida, R E; Molina, R D I; Viola, C M; Luciardi, M C; Nieto Peñalver, C; Bardón, A; Arena, M E

    2017-08-01

    Quorum sensing (QS) is a cell-to-cell signaling communication system that controls the virulence behavior of a broad spectrum of bacterial pathogens, participating also in the development of biofilms, responsible of the antibiotic ineffectiveness in many infections. Therefore, QS system is an attractive target for antimicrobial therapy. In this study, we compare the effect of seven structurally related coumarins against bacterial growth, biofilm formation and elastase activity of Pseudomonas aeruginosa. In addition, the anti-pathogenic capacity of the seven coumarins was evaluated on the wild type and the biosensor strain of Chromobacterium violaceum. The comparative study of coumarins showed that molecules with hydroxyl groups on the aromatic ring displayed higher activity on the inhibition of biofilm formation of P. aeruginosa over coumarins with substituents in positions 3 and 4 or without the double 3,4-bond. These 3 or 4-hydroxylated positions caused a decrease in the anti-biofilm activity obtained for coumarin. However, the hydroxyl group in position 3 of the pyrone ring was important for the inhibition of C. violaceum QS and elastolytic activity of P. aeruginosa. The effects observed were active independently of any effect on growth. According to our results, coumarin and its hydroxylated derivatives represent an interesting group of compounds to use as anti-virulence agents against the human pathogen P. aeruginosa. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Isoflavonoids and coumarins from Glycyrrhiza uralensis: antibacterial activity against oral pathogens and conversion of isoflavans into isoflavan-quinones during purification.

    Science.gov (United States)

    Gafner, Stefan; Bergeron, Chantal; Villinski, Jacquelyn R; Godejohann, Markus; Kessler, Pavel; Cardellina, John H; Ferreira, Daneel; Feghali, Karine; Grenier, Daniel

    2011-12-27

    Phytochemical investigation of a supercritical fluid extract of Glycyrrhiza uralensis has led to the isolation of 20 known isoflavonoids and coumarins, and glycycarpan (7), a new pterocarpan. The presence of two isoflavan-quinones, licoriquinone A (8) and licoriquinone B (9), in a fraction subjected to gel filtration on Sephadex LH-20 is due to suspected metal-catalyzed oxidative degradation of licoricidin (1) and licorisoflavan A (2). The major compounds in the extract, as well as 8, were evaluated for their ability to inhibit the growth of several major oral pathogens. Compounds 1 and 2 showed the most potent antibacterial activities, causing a marked growth inhibition of the cariogenic species Streptococcus mutans and Streptococcus sobrinus at 10 μg/mL and the periodontopathogenic species Porphyromonas gingivalis (at 5 μg/mL) and Prevotella intermedia (at 5 μg/mL for 1 and 2.5 μg/mL for 2). Only 1 moderately inhibited growth of Fusobacterium nucleatum at the highest concentration tested (10 μg/mL).

  15. Binding of coumarins to human serum albumin. Study by equilibrium dialysis; Union de cumarinas a seroalbumina humana. Estudio por dialisis en el equilibrio

    Energy Technology Data Exchange (ETDEWEB)

    Zaton Lopez, A.M.L.; Ferrer Lopez, J.M. [Departamento de Bioquimica y Biologia Molecular, Universidad del Pais Vasco, Facultad de Farmacia, Vitoria (Spain)

    1995-12-31

    In order to find the typical structure of ligands that could displace the binding of warfarin on human serum albumin, the binding parameters of several coumarin derivatives have been compared. Warfarin, hydroxy coumarin, coumarin, acetyl coumarin and chromanol, bind to two different sites on seroalbumin. In the primary binding site, the affinity for the 4-hydroxyl compounds (4-chromanol, warfarin and 4-hidroxycoumarin) are larger than for coumarin and 3-acetyl coumarin. this high-affinity binding site, warfarin binding site, is the region in which the specific binding of warfarin and 4-hydroxybenzopyrans occurs. the 4-chromanol is the smallest ligand which binds to seroalbumin with high-affinity, and its structure is typical in ligands which specifically bind to the warfarin binding site. (Author) 23 refs.

  16. Thermospray and particle beam liquid chromatographic-mass spectrometric analysis of coumarin anticoagulants.

    Science.gov (United States)

    de Vries, J X; Kymber, K A

    1991-01-02

    Positive ion mass spectra were obtained from several coumarin oral anticoagulants (phenprocoumon, warfarin, acenocoumarol and dicoumarol) and derivatives by liquid chromatography-thermospray mass spectrometry (LC-TSP-MS) and liquid chromatography-electron impact mass spectrometry (LC-EI-MS) to assess the use of LC-MS methods for the determination of these compounds in biological materials. LC-TSP mass spectra showed a single [M + 1]+ ion with no fragmentation; LC-EI mass spectra showed fragment ions which were similar in mass and relative intensities to those obtained by conventional EI-MS. These data should serve as a basis for the development of LC-MS methods for the qualitative and quantitative analysis of coumarin anticoagulants in biological samples. LC-TSP-MS was applied to the determination of phenprocoumon in a plasma extract from an anticoagulated patient.

  17. Coumarin-Rhodamine Hybrids-Novel Probes for the Optical Measurement of Viscosity and Polarity.

    Science.gov (United States)

    Scholz, Norman; Jadhav, Amol; Shreykar, Milind; Behnke, Thomas; Nirmalananthan, Nithiya; Resch-Genger, Ute; Sekar, Nagaiyan

    2017-11-01

    A comprehensive systematic study of absorption and fluorescence properties in solvents of varying viscosity and polarity of three novel and red-emitting coumarin-rhodamine hybrid derivatives with differences in the rigidity of their substituents is presented. This includes ethanol-polyethylene glycol, toluene-polyethylene glycol, and toluene-paraffin mixtures. Moreover, protonation-induced effects on the spectroscopic properties are studied. A viscosity-induced emission enhancement was observed for all coumarin-rhodamine hybrid derivatives. MCR2 bearing a julolidine donor showed the expected low sensitivity to viscosity whereas MCR3 with its freely rotatable diphenylamino substituent revealed a particularly pronounced sensitivity to this parameter. Moreover, MCR2 shows an enhancement in emission in the open, i.e., protonated form in conjunction with a largely Stokes shift fluorescence in the deep red spectral region. This enables the application of these dyes as viscosity sensors and as far red emitting pH-sensitive probes.

  18. Photo-controlled release of fipronil from a coumarin triggered precursor.

    Science.gov (United States)

    Gao, Zhenhong; Yuan, Pengtao; Wang, Donghui; Xu, Zhiping; Li, Zhong; Shao, Xusheng

    2017-06-01

    Developing efficient controlled release system of insecticide can facilitate the better use of insecticide. We described here a first example of photo-controlled release of an insecticide by linking fipronil with photoresponsive coumarin covalently. The generated coumarin-fipronil (CF) precursor could undergo cleavage to release free fipronil in the presence of blue light (420nm) or sunlight. Photophysical studies of CF showed that it exhibited strong fluorescence properties. The CF had no obvious activity against mosquito larvae under dark, but it can be activated by light inside the mosquito larvae. The released Fip from CF by blue light irradiation in vitro retained its activity to armyworm (Mythimna separate) with LC50 value of 24.64μmolL-1. This photocaged molecule provided an alternative delivery method for fipronil. Copyright © 2017. Published by Elsevier Ltd.

  19. Vasorelaxing effect of coumarins from Cnidium monnieri on rabbit corpus cavernosum.

    Science.gov (United States)

    Chiou, W F; Huang, Y L; Chen, C F; Chen, C C

    2001-04-01

    Bioassay-directed fractionation led to the identification of four known coumarins, osthole (1), imperatorin (2), xanthotoxin (3), and isopimpinellin (4), from the ethanolic extract of the fruit of Cnidium monnieri (L.) Cusson. In phenylephrine (PE)-precontracted endothelium-intact rabbit corpus cavernosum, all four coumarins exhibited relaxing effect with the IC50 values for compounds 1, 2, 3, and 4 determined to be 2.14 +/- 0.73, 0.85 +/- 0.16, 1.24 +/- 0.45, and 18.4 +/- 8.10 microM, respectively. The four compounds were identified by comparison of their physical data (EIMS, 1H- and 13C-NMR) with those from published reports.

  20. Inhibitory effect of coumarin derivatives on apple (cv. Idared polyphenol oxidase

    Directory of Open Access Journals (Sweden)

    I. Strelec

    2017-01-01

    Full Text Available Inhibitory effect of 32 coumarin derivatives (20 Schiff bases, 5 thiosemicarbazides, 5 thiazolidinones, and their precursors, 7-hydroxy-4-methylcoumarin and 4-methylcoumarin-7-yl hydrazine carboxylate on partially purified apple polyphenol oxidase was investigated. Thirteen coumarin derivatives inhibited polyphenol oxidase (5 Schiff bases, 5 thiosemicarbazides, 1 thiazolidinone, 4-methyl-7-hydroxycoumarin and 4-methylcoumarin-7-yl hydrazine carboxylate, while 19 derivatives showed no effect on enzyme activity. The most effective inhibitors were thiosemicarbazides, with 4-methyl-1-(2-(4-methyl-2-oxo-2H-chromen-7-yloxyacetyl thiosemicarbazide (compound C23 being the most prominent inhibitor (IC50 = 10.45 µM. The importance of thiosemicarbazide moiety as crucial structure element for strong apple PPO inhibition was confirmed by its cyclisation to thiazolidinone bearing the same substituents as corresponding thiosemicarbazide. Capture of the sulphur atom of thiosemicarbazide group within tiazolidinone ring caused significant loss of inhibitory effect against apple PPO.

  1. Cumarinas e alcaloides de Rauia resinosa (rutaceae Coumarins and alkaloids from Rauia resinosa (rutaceae

    Directory of Open Access Journals (Sweden)

    Tatiane Regina Albarici

    2010-01-01

    Full Text Available The genus Rauia, that is poorly chemically studied, belongs to the Rutaceae family. This family has been known to contain a large variety of secondary metabolites. Our phytochemical investigation of the stem and leaves of Rauia resinosa has led to the identification of the structurally related coumarins: murralongin (1, murrangatin (2, munomicrolin (3, murrangatin diacetate (4, umbelliferone (5, rauianin (6 and one novel coumarin: 3-ethylrauianin (7; the alkaloids: N-methyl-4-methoxy-2-quinolone (8, mirtopsine (9, dictamine (10, γ-fagarine (11, skimmianine (12, Z-dimethylrhoifolinate (13, zantodioline (14, zantobungeanine (15, veprissine (16, one novel alkaloid 7-hydroxy-8-methoxy-N-methylflindersine (17 and 8-hydroxy-N-methylflindersine (18 that is described as a natural product for the first time, and a mixture of steroids: as sitosterol and stigmasterol.

  2. A new coumarin and cytotoxic activities of constituents from Cinnamomum cassia.

    Science.gov (United States)

    Ngoc, Tran Minh; Nhiem, Nguyen Xuan; Khoi, Nguyen Minh; Son, Doan Cao; Hung, Tran Viet; Van Kiem, Phan

    2014-04-01

    A new coumarin derivative, coumacasia (1) and eight known compounds, coumarin (2), cinnamaldehyde (3), 2-methoxycinnamaldehyde (4), 2-hydroxycinnamaldehyde (5), coniferaldehyde (6), cinnamic acid (7), 2-hydroxycinnamic acid (8), and cinnamic alcohol (9), were isolated from the methanol extract of Cinnamomum cassia. Their structures were elucidated by spectral data and by comparison with the reported literature. The cytotoxic activities of compounds 1-9 were evaluated with two human cancer cell lines, HL-60 and A-549. Compound 1 showed growth inhibitory effects in the HL-60 and A-549 cell lines with IC50 values of 8.2 +/- 0.5 and 11.3 +/- 1.1 microM, respectively. Compounds 3-6, and 8 exhibited moderate cytotoxicity with IC50 values ranging from 20.5 to 65.6 microM.

  3. Coumarin-BODIPY hybrids by heteroatom linkage: versatile, tunable and photostable dye lasers for UV irradiation.

    Science.gov (United States)

    Esnal, I; Duran-Sampedro, G; Agarrabeitia, A R; Bañuelos, J; García-Moreno, I; Macías, M A; Peña-Cabrera, E; López-Arbeloa, I; de la Moya, S; Ortiz, M J

    2015-03-28

    Linking amino and hydroxycoumarins to BODIPYs through the amino or hydroxyl group lets the easy construction of unprecedented photostable coumarin-BODIPY hybrids with broadened and enhanced absorption in the UV spectral region, and outstanding wavelength-tunable laser action within the green-to-red spectral region (∼520-680 nm). These laser dyes allow the generation of a valuable tunable UV (∼260-350 nm) laser source by frequency doubling, which is essential to study accurately the photochemistry of biological molecules under solar irradiation. The tunability is achieved by selecting the substitution pattern of the hybrid. Key factors are the linking heteroatom (nitrogen vs. oxygen), the number of coumarin units joined to the BODIPY framework and the involved linking positions.

  4. Anti-inflammatory and antimicrobial coumarins from the stems of Eurya chinensis.

    Science.gov (United States)

    Song, Jia-Ling; Yuan, Yao; Tan, Hai-Bo; Huang, Ri-Ming; Liu, Hong-Xin; Xu, Zhi-Fang; Qiu, Sheng-Xiang

    2017-03-01

    Two new coumarins, named (±)-euryacoumarin A (1) and 6-demethylobtusinin (2), and one new natural coumarin, named euryacoumarin B (3), along with two known compounds, scopoletin (4) and obtusinol (5), were isolated from the stems of Eurya chinensis. Their structures were elucidated by means of extensive spectroscopic methods and comparison with data reported in the literatures. Compound 1 exhibited significant inhibition of LPS-induced nitric oxide (NO) production in RAW264.7 cells with IC50 value of 35.64 ± 1.73 μM, and showed marginal antibacterial activities against Bacillus subtilis and B. cereus with MIC values of 50.59 ± 2.12 and 35.42 ± 0.96 μM, respectively.

  5. Coumarins and flavonoid from Murraya paniculata (L.) Jack: Antibacterial and anti-inflammation activity.

    Science.gov (United States)

    Rodanant, Pirasut; Khetkam, Pichit; Suksamrarn, Apichart; Kuvatanasuchati, Jintakorn

    2015-11-01

    The ethyl acetate extract of leaves of Murraya paniculata (L.) Jack was described in the previous in vitro study on the inhibition effect on the growth of periodontopathic bacteria and the reduction of cytokines from LPS-stimulated macrophages. In this study, four coumarins including murrangatin (1), murrangatin acetate (2), murranganonesenecionate (3), micropubescin (4) and one flavonoid, 3', 4', 5', 7-tetramethoxyflavone (5) were isolated from the leaves of ethyl acetate extract of M. paniculata. MTT assay was used to test cytotoxicity on human gingival fibroblast and monocytes. The isolated compounds were evaluated for their antibacterial effect against Porphyromonas gingivalis (ATCC33277) and anti-inflammation on lipopolysaccharide-stimulated inflammation using monocyte cells. All isolated compounds exhibited antibacterial activity against P. gingivalis (ATCC 33277). Murranganonesenecionate (3) was highly potent anti-inflammation properties. The coumarin constituents from M. paniculata leaves might be potential lead molecules for the development of antimicrobial drugs for treating periodontal disease.

  6. Disesquiterpene and sesquiterpene coumarins from Ferula pseudalliacea, and determination of their absolute configurations.

    Science.gov (United States)

    Dastan, Dara; Salehi, Peyman; Reza Gohari, Ahmad; Zimmermann, Stefanie; Kaiser, Marcel; Hamburger, Matthias; Reza Khavasi, Hamid; Ebrahimi, Samad Nejad

    2012-06-01

    The first disesquiterpene coumarin, sanandajin, five sesquiterpene coumarins, kamolonol acetate, fekrynol acetate, ethyl galbanate, methyl galbanate, farnesiferol B, and a sesquiterpene, aristolone, were isolated from a n-hexane extract of Ferula pseudalliacea roots. The structures were elucidated by 1D and 2D NMR, HR-ESIMS data, and kamolonol acetate was confirmed by single-crystal X-ray analysis. The absolute configuration of compounds was established by comparison of experimental and simulated ECD spectra using time dependence density function theory (TDDFT). In vitro antiplasmodial activity against Plasmodium falciparum K1 strain was determined. sanandajin, kamolonol acetate and methyl galbanate showed moderate antiplasmodial activity, with IC(50) values of 2.6, 16.1 and 7.1 μM, respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Benzofuran glycosides and coumarins from the bark of Streblus indicus (Bur.) Corner.

    Science.gov (United States)

    He, Ruijie; Zhang, Yanjun; Wu, Liangdeng; Nie, Hui; Huang, Yan; Liu, Buming; Deng, Shengping; Yang, Ruiyun; Huang, Shuai; Nong, Zhijie; Li, Jun; Chen, Haiyan

    2017-06-01

    Two pairs of rare benzofuran glucoside epimers, indicuses A and B and indicuses C and D, three biogenetically related compounds indicuses E-G, and one coumarin indicus H, as well as 11 known compounds, were isolated from the bark of Streblus indicus (Bur.) Corner. The structures of indicuses A-H were elucidated by NMR and MS data, as well as by CD. (S)-Marmesinin exhibited moderate antimicrobial activity in vitro against Bacillus subtilis and Saccharomyces cerevisiae. 7,8-Dihydroxy-3-(3-methyl-2-butenyl) coumarin, umbelliferone, and scopoletin displayed strong cytotoxic activity in vitro against human bladder carcinoma cell line EJ. The structure-activity relationships indicate that hydroxylation at C-7 in the cytotoxic compounds is crucial to their activities. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Coumarin and alkaloids of Rauia resinosa (Rutaceae); Cumarinas e alcaloides de Rauia resinosa (Rutaceae)

    Energy Technology Data Exchange (ETDEWEB)

    Albarici, Tatiane Regina; Vieira, Paulo Cezar; Fernandes, Joao Batista; Silva, Maria Fatima das Gracas Fernandes da, E-mail: paulo@dq.ufscar.b [Universidade Federal de Sao Carlos (UFSCAR), SP (Brazil). Dept. de Quimica; Pirani, Jose Rubens [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Biociencias. Dept. de Botanica

    2010-07-01

    The genus Rauia, that is poorly chemically studied, belongs to the Rutaceae family. This family has been known to contain a large variety of secondary metabolites. Our phytochemical investigation of the stem and leaves of Rauia resinosa has led to the identification of the structurally related coumarins: murralongin (1), murrangatin (2), munomicrolin (3), murrangatin diacetate (4), umbelliferone (5), rauianin (6) and one novel coumarin: 3-ethylrauianin (7); the alkaloids: N-methyl-4-methoxy-2-quinolone (8), mirtopsine (9), dictamine (10), g-fagarine (11), skimmianine (12), Z-dimethylrhoifolinate (13), zantodioline (14), zantobungeanine (15), veprissine (16), one novel alkaloid 7-hydroxy-8-methoxy-N-methylflindersine (17) and 8-hydroxy-N-methylflindersine (18) that is described as a natural product for the first time, and a mixture of steroids: as sitosterol and stigmasterol. (author)

  9. A Coumarin-Based Fluorescent Probe as a Central Nervous System Disease Biomarker

    OpenAIRE

    Yap, Ann-Chee; Mahamad, Ummi; Lim, Shen-Yang; Kim, Hae-Jo; Choo, Yeun-Mun

    2014-01-01

    Homocysteine and methylmalonic acid are important biomarkers for diseases associated with an impaired central nervous system (CNS). A new chemoassay utilizing coumarin-based fluorescent probe 1 to detect the levels of homocysteine is successfully implemented using Parkinson's disease (PD) patients' blood serum. In addition, a rapid identification of homocysteine and methylmalonic acid levels in blood serum of PD patients was also performed using the liquid chromatography-mass spectrometry (LC...

  10. Valorisation des plantes médicinales à coumarines des marchés de ...

    African Journals Online (AJOL)

    SARAH

    30 janv. 2015 ... Mpondo et al.. J. Appl. Biosci. Valorisation des plantes médicinales à coumarines des marchés de Douala Est (Cameroun). 7810. Flatulences. Feuilles fraiches, graines. Décoction (1,5 l d'eau avec. 750 ml pendant 30 mn, y ajouter du jus de carotte et de céleri). Voie orale (boire 1 verre tous les matins).

  11. Laser-induced fluorescence of jet-cooled 7-diethylamino-4-trifluoromethyl coumarin

    Science.gov (United States)

    Taylor, A. G.; Bouwman, W. G.; Jones, A. C.; Guo, C.; Phillips, D.

    1988-03-01

    Laser-induced fluorescence excitation and emission spectra of 7-diethylamino-4-trifluoromethyl coumarin (C152A) cooled in a supersonic expansion of helium are reported. The lowest observed excitation band is assigned as the vibrationless. 0 00 transition in disagreement with a previous assignment. The present assignment is consistent with a Franck-Condon simulation of the spectral intensities. No evidence was found for the formation of a twisted intramolecular charge transfer (TICT) state by the isolated jet-cooled molecule.

  12. Coumarins from Angelica decursiva inhibit α-glucosidase activity and protein tyrosine phosphatase 1B.

    Science.gov (United States)

    Ali, Md Yousof; Jannat, Susoma; Jung, Hyun Ah; Jeong, Hyong Oh; Chung, Hae Young; Choi, Jae Sue

    2016-05-25

    In the present study, we investigated the anti-diabetic potential of six natural coumarins, 4-hydroxy Pd-C-III (1), 4'-methoxy Pd-C-I (2), decursinol (3), decursidin (4), umbelliferone 6-carboxylic acid (5), and 2'-isopropyl psoralene (6) isolated from Angelica decursiva and evaluated their inhibitory activities against protein tyrosine phosphatase 1B (PTP1B), α-glucosidase, and ONOO(-)-mediated protein tyrosine nitration. Coumarins 1-6 showed potent PTP1B and α-glucosidase inhibitory activities with ranges of IC50 values of 5.39-58.90 μM and 65.29-172.10 μM, respectively. In the kinetic study for PTP1B enzyme inhibition, compounds 1, 5, and 6 were competitive, whereas 2 and 4 showed mixed type, and 3 displayed noncompetitive type inhibition. For α-glucosidase enzyme inhibition, compounds 1 and 3 exhibited good mixed-type, while 2, 5, and 6 showed noncompetitive and 4 displayed competitive type inhibition. Furthermore, these coumarins also effectively suppressed ONOO(-)-mediated tyrosine nitration in a dose-dependent manner. To further investigate PTP1B inhibition, we generated a 3D structure of PTP1B using Autodock 4.2 and simulated the binding of compounds 1-6. Docking simulations showed that different residues of PTP1B interacted with different functional groups of compounds 1-6 through hydrogen and hydrophobic interactions. In addition, the binding energies of compounds 1-6 were negative, suggesting that hydrogen bonding may stabilize the open form of the enzyme and potentiate tight binding of the active site of PTP1B, thereby resulting in more effective PTP1B inhibition. These results demonstrate that the whole plant of A. decursiva and its coumarins are useful as potential functional food ingredients for the prevention and treatment of type 2 diabetes. Copyright © 2016. Published by Elsevier Ireland Ltd.

  13. Synthesis and biological evaluation of coumarin derivatives containing imidazole skeleton as potential antibacterial agents.

    Science.gov (United States)

    Hu, Yang; Shen, Yufeng; Wu, Xiaohu; Tu, Xiao; Wang, Gao-Xue

    2018-01-01

    Emergence of multidrug-resistant bacteria causes an urgent need for new generation of antibiotics, which may have a different mechanism of inhibition or killing action from the existing. Here, we report on the design, synthesis, and biological evaluation of thirty-nine coumarin derivatives in order to solve the antibacterial resistance by targeting at the inhibition of biosynthesis pathway of fatty acids. Their antibacterial activities against Escherichia coli, Staphylococcus aureus, Streptococcus agalactiae, and Flavobacterium cloumnare are tested and action mechanism against the key enzyme in bacterial fatty acid synthesis pathway are studied. The results show that compounds 13 and 18 have potent and broad spectrum antimicrobial activity. In addition, 9, 14 and 19 show eminent antimicrobial efficacy toward S. aureus, S. agalactiae, and F. cloumnare. Mechanistically, coumarin derivatives display the antibacterial activity via the control of FabI and FabK function. The structure-activity relationship analysis indicate that the length of linker and imidazole substitute group could significantly influence the antimicrobial activity, as well as the inhibitory activity against FabI and FabK. The structural optimization analysis of coumarin suggest that derivatives 9, 13, 14, 18 and 19 could be a viable way of preventing and controlling bacteria and considered as promising lead compounds for the development of commercial drugs. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  14. Resveratrol and Coumarin: Novel Agricultural Antibacterial Agent against Ralstonia solanacearum In Vitro and In Vivo

    Directory of Open Access Journals (Sweden)

    Juanni Chen

    2016-11-01

    Full Text Available Bacterial wilt is a destructive disease caused by the phytopathogen Ralstonia solanacearum (R. solanacearum, which is widely found in various tobacco-growing areas all over the world. Botanical bactericidal substances have gradually emerged as a hot topic in modern pesticide research. In this study, the antibacterial activities of two phytochemicals (resveratrol and coumarin against R. solanacearum and their in vivo and in vitro efficacy for controlling tobacco bacterial wilt were evaluated. We rule out significant biological effects of both phytochemicals using transmission electron microscope (TEM and fluorescence microscope, which suppressed the growth of R. solanacearum. Furthermore, we demonstrated that the toxicity mechanisms mainly involved damaging bacterial cell membrane and preventing swarming motility and biofilm formation. A further pot experiment demonstrated that coumarin and resveratrol significantly inhibited early adhesion and colonization of R. solanacearum in tobacco plants and the corresponding control efficacies were 68% and 85% after incubation for 13 days, respectively. The findings of this study suggest that both resveratrol and coumarin have potential as non-toxic antimicrobial strategies for controlling tobacco bacterial wilt disease.

  15. Photophysics of a coumarin based Schiff base in solvents of varying polarities

    Science.gov (United States)

    Ghosh, Saptarshi; Roy, Nayan; Singh, T. Sanjoy; Chattopadhyay, Nitin

    2018-01-01

    The present work reports detailed photophysics of a coumarin based Schiff base, namely, (E)-7-(((8-hydroxyquinolin-2-yl)methylene)amino)-4-methyl-2H-chromen-2-one (HMC) in different solvents of varying polarity exploiting steady state absorption, fluorescence and time resolved fluorescence spectroscopy. The dominant photophysical features of HMC are discussed in terms of emission from an intramolecular charge transfer (ICT) excited state. Molecular orbital (MO) diagrams as obtained from DFT based computational analysis confirms the occurrence of charge transfer from 8‧-hydroxy quinoline moiety of the molecule to the coumarin part. The notable difference in the photophysical response of HMC from its analogous coumarin (C480) lies in a lower magnitude of fluorescence quantum yield of the former, particularly in the solvents of low polarity, which is rationalized by considering the higher rate of non-radiative decay of HMC in apolar solvents. Phosphorescence emission as well as phosphorescence lifetime of HMC has also been reported in 77 K frozen matrix.

  16. Antimicrobial and Antioxidant Activities of Coumarins from the Roots of Ferulago campestris (Apiaceae

    Directory of Open Access Journals (Sweden)

    2009-02-01

    Full Text Available We report the isolation of several coumarins and the stereochemical assessment of some pyranocoumarins, as well as the antibacterial and antioxidant activities of the three most abundant ones (grandivittin, agasyllin and aegelinol benzoate isolated from the roots of Ferulago campestris collected in Sicily and of the hydrolysis product (aegelinol. Aegelinol and agasyllin showed antibacterial activity against nine ATCC and the same clinically isolated Gram-positive and Gram-negative bacterial strains. At a concentration between 16 and 125 mg/mL both coumarins showed a significant antibacterial effect against both Gram-negative and Gram-positive bacteria. In particular the ATCC strains Staphylococcus aureus, Salmonella thypii, Enterobacter cloacae and Enterobacter earogenes (MIC = 16 and 32 mg/mL for aegelinol and agasyllin, respectively were the most inhibited. Antibacterial activity was also found against Helicobacter pylori: a dose-dependent inhibition was shown between 5 and 25 mg/mL. The antioxidant activity of the coumarins was evaluated by their effects on human whole blood leukocytes (WB and on isolated polymorphonucleate (PMN chemiluminescence (CL, PMA-stimulated and resting.

  17. Anticancer Natural Coumarins as Lead Compounds for the Discovery of New Drugs.

    Science.gov (United States)

    Pinto, Diana C G A; Silva, Artur M S

    2017-12-14

    Cancer is one of the most serious illnesses of our civilization. The International Agency for Research on Cancer estimated that 14.1 million new cancer cases were diagnosed. Therefore, the cure efficiency of cancer chemotherapy depends not only on how the anticancer drug is delivered to its targets but also on the anticancer drug itself. Among the approved drugs 80% are derived from natural compounds. In this sense, coumarins, natural polyphenols for which anticancer activity has been proved, can be a source or inspire the synthesis of new anticancer agents. Several natural coumarins, such as scopoletin, daphnetin, esculetin and the less known wedelolactone and galbanic acid, appear to have promising anticancer activities. This paper will provide a comprehensive overview of the advances on natural coumarins with potential therapeutic applications as anticancer agents highlighting the ones for which the mechanism of action is well defined and can serve as lead compounds for the design of new more potent molecules. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  18. Solution-phase Synthesis of a Combinatorial Library of 3-[4-(Coumarin-3-yl)-1,3-thiazol-2-ylcarbamoyl]propanoic acid Amides

    OpenAIRE

    Zhuravel, I.; Kovalenko, S.; Vlasov, S.; Chernykh, V.

    2005-01-01

    The parallel solution-phase synthesis of a new combinatorial library of 3-[4-(R1-coumarin-3-yl)-1,3-thiazol-2-ylcarbamoyl]propanoic acid amides 9 has been developed. The synthesis involves two steps: 1) the synthesis of core building blocks – 3- [4-(coumarin-3-yl)-1,3-thiazol-2-ylcarbamoyl]propanoic acids, 6 – by the reaction of 3-(É-bromacetyl)coumarins 1 with 3-amino(thioxo)methylcarbamoylpropanoic acid (5); 2) the synthesis of the corresponding 3-[4-(coumarin-3-yl)-1,3-thiazol-...

  19. The Distribution of Coumarins and Furanocoumarins in Citrus Species Closely Matches Citrus Phylogeny and Reflects the Organization of Biosynthetic Pathways.

    Science.gov (United States)

    Dugrand-Judek, Audray; Olry, Alexandre; Hehn, Alain; Costantino, Gilles; Ollitrault, Patrick; Froelicher, Yann; Bourgaud, Frédéric

    2015-01-01

    Citrus plants are able to produce defense compounds such as coumarins and furanocoumarins to cope with herbivorous insects and pathogens. In humans, these chemical compounds are strong photosensitizers and can interact with medications, leading to the "grapefruit juice effect". Removing coumarins and furanocoumarins from food and cosmetics imply additional costs and might alter product quality. Thus, the selection of Citrus cultivars displaying low coumarin and furanocoumarin contents constitutes a valuable alternative. In this study, we performed ultra-performance liquid chromatography coupled with mass spectrometry analyses to determine the contents of these compounds within the peel and the pulp of 61 Citrus species representative of the genetic diversity all Citrus. Generally, Citrus peel contains larger diversity and higher concentrations of coumarin/furanocoumarin than the pulp of the same fruits. According to the chemotypes found in the peel, Citrus species can be separated into 4 groups that correspond to the 4 ancestral taxa (pummelos, mandarins, citrons and papedas) and extended with their respective secondary species descendants. Three of the 4 ancestral taxa (pummelos, citrons and papedas) synthesize high amounts of these compounds, whereas mandarins appear practically devoid of them. Additionally, all ancestral taxa and their hybrids are logically organized according to the coumarin and furanocoumarin pathways described in the literature. This organization allows hypotheses to be drawn regarding the biosynthetic origin of compounds for which the biogenesis remains unresolved. Determining coumarin and furanocoumarin contents is also helpful for hypothesizing the origin of Citrus species for which the phylogeny is presently not firmly established. Finally, this work also notes favorable hybridization schemes that will lead to low coumarin and furanocoumarin contents, and we propose to select mandarins and Ichang papeda as Citrus varieties for use in

  20. The Distribution of Coumarins and Furanocoumarins in Citrus Species Closely Matches Citrus Phylogeny and Reflects the Organization of Biosynthetic Pathways

    Science.gov (United States)

    Dugrand-Judek, Audray; Olry, Alexandre; Hehn, Alain; Costantino, Gilles; Ollitrault, Patrick; Froelicher, Yann; Bourgaud, Frédéric

    2015-01-01

    Citrus plants are able to produce defense compounds such as coumarins and furanocoumarins to cope with herbivorous insects and pathogens. In humans, these chemical compounds are strong photosensitizers and can interact with medications, leading to the “grapefruit juice effect”. Removing coumarins and furanocoumarins from food and cosmetics imply additional costs and might alter product quality. Thus, the selection of Citrus cultivars displaying low coumarin and furanocoumarin contents constitutes a valuable alternative. In this study, we performed ultra-performance liquid chromatography coupled with mass spectrometry analyses to determine the contents of these compounds within the peel and the pulp of 61 Citrus species representative of the genetic diversity all Citrus. Generally, Citrus peel contains larger diversity and higher concentrations of coumarin/furanocoumarin than the pulp of the same fruits. According to the chemotypes found in the peel, Citrus species can be separated into 4 groups that correspond to the 4 ancestral taxa (pummelos, mandarins, citrons and papedas) and extended with their respective secondary species descendants. Three of the 4 ancestral taxa (pummelos, citrons and papedas) synthesize high amounts of these compounds, whereas mandarins appear practically devoid of them. Additionally, all ancestral taxa and their hybrids are logically organized according to the coumarin and furanocoumarin pathways described in the literature. This organization allows hypotheses to be drawn regarding the biosynthetic origin of compounds for which the biogenesis remains unresolved. Determining coumarin and furanocoumarin contents is also helpful for hypothesizing the origin of Citrus species for which the phylogeny is presently not firmly established. Finally, this work also notes favorable hybridization schemes that will lead to low coumarin and furanocoumarin contents, and we propose to select mandarins and Ichang papeda as Citrus varieties for use in

  1. Thermodynamics of Enzyme-Catalyzed Reactions Database

    Science.gov (United States)

    SRD 74 Thermodynamics of Enzyme-Catalyzed Reactions Database (Web, free access)   The Thermodynamics of Enzyme-Catalyzed Reactions Database contains thermodynamic data on enzyme-catalyzed reactions that have been recently published in the Journal of Physical and Chemical Reference Data (JPCRD). For each reaction the following information is provided: the reference for the data, the reaction studied, the name of the enzyme used and its Enzyme Commission number, the method of measurement, the data and an evaluation thereof.

  2. Thiosemicarbazone modification of 3-acetyl coumarin inhibits Aβ peptide aggregation and protect against Aβ-induced cytotoxicity.

    Science.gov (United States)

    Ranade, Dnyanesh S; Bapat, Archika M; Ramteke, Shefali N; Joshi, Bimba N; Roussel, Pascal; Tomas, Alain; Deschamps, Patrick; Kulkarni, Prasad P

    2016-10-04

    Aggregation of amyloid β peptide (Aβ) is an important event in the progression of Alzheimer's disease. Therefore, among the available therapeutic approaches to fight with disease, inhibition of Aβ aggregation is widely studied and one of the promising approach for the development of treatments for Alzheimer's disease. Thiosemicarbazone compounds are known for their variety of biological activities. However, the potential of thiosemicarbazone compounds towards inhibition of Aβ peptide aggregation and the subsequent toxicity is little explored. Herein, we report synthesis and x-ray crystal structure of novel compound 3-acetyl coumarin thiosemicarbazone and its efficacy toward inhibition of Aβ(1-42) peptide aggregation. Our results indicate that 3-acetyl coumarin thiosemicarbazone inhibits Aβ(1-42) peptide aggregation up to 80% compared to the parent 3-acetyl coumarin which inhibits 52%. Further, 3-acetyl coumarin thiosemicarbazone provides neuroprotection against Aβ-induced cytotoxicity in SH-SY5Y cell line. These findings indicate that thiosemicarbazone modification renders 3-acetyl coumarin neuroprotective properties. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  3. Controlled enzyme catalyzed heteropolysaccharide degradation

    DEFF Research Database (Denmark)

    Rasmussen, Louise Enggaard

    of the progress of enzymatic hydrolysis of different xylan substrates was developed. The method relies on dividing the HPSEC elution profiles into fixed time intervals and utilizing the linear refractive index response (area under the curve) of defined standard compounds. In order to obtain optimal high......-performance size exclusion chromatography profiles, the method was designed using 0.1 M CH3COONa in both the mobile phase and as the sample solution. This was based on the systematic evaluation of the influence of the mobile phase, including the type, ionic strength and pH, on the refractive index detector...... response. A time study of the enzyme catalyzed hydrolysis of birchwood xylan and wheat bran by BsX was used as an example to demonstrate the workability of the new HPSEC method for obtaining progress curves describing the evolution in the product profile during enzyme catalysis. Flaxseed mucilage (FM) has...

  4. Gold-catalyzed naphthalene functionalization

    Directory of Open Access Journals (Sweden)

    Iván Rivilla

    2011-05-01

    Full Text Available The complexes IPrMCl (IPr = 1,3-bis(diisopropylphenylimidazol-2-ylidene, M = Cu, 1a; M = Au, 1b, in the presence of one equiv of NaBAr'4 (Ar' = 3,5-bis(trifluoromethylphenyl, catalyze the transfer of carbene groups: C(RCO2Et (R = H, Me from N2C(RCO2Et to afford products that depend on the nature of the metal center. The copper-based catalyst yields exclusively a cycloheptatriene derivative from the Buchner reaction, whereas the gold analog affords a mixture of products derived either from the formal insertion of the carbene unit into the aromatic C–H bond or from its addition to a double bond. In addition, no byproducts derived from carbene coupling were observed.

  5. Fluorescent Polymer Incorporating Triazolyl Coumarin Units for Cu2+ Detection via Planarization of Ict-Based Fluorophore

    Science.gov (United States)

    Ngororabanga, Jean Marie Vianney; Du Plessis, Jacolien; Mama, Neliswa

    2017-01-01

    A novel fluorescent polymer with pendant triazolyl coumarin units was synthesized through radical polymerization. The polymer showed reasonable sensitivity and selectivity towards Cu2+ in acetonitrile in comparison to other tested metal ions with a significant quenching effect on fluorescence and blue shifting in the range of 20 nm. The blue shift was assigned to the conformation changes of the diethylamino group from the coumarin moiety which led to planarization of the triazolyl coumarin units. The possible binding modes for Cu2+ towards the polymer were determined through the comparison of the emission responses of the polymer, starting vinyl monomer and reference compound, and the triazole ring was identified as one of the possible binding sites for Cu2+. The detection limits of the polymer and vinyl monomer towards Cu2+ were determined from fluorescence titration experiments and a higher sensitivity (35 times) was observed for the polymer compared with its starting monomer. PMID:28867764

  6. Can laccases catalyze bond cleavage in lignin?

    DEFF Research Database (Denmark)

    Munk, Line; Sitarz, Anna Katarzyna; Kalyani, Dayanand

    2015-01-01

    these enzymes may help degrading lignin, using oxygen as the oxidant. Laccases can catalyze polymerization of lignin, but the question is whether and how laccases can directly catalyze modification of lignin via catalytic bond cleavage. Via a thorough review of the available literature and detailed...... illustrations of the putative laccase catalyzed reactions, including the possible reactions of the reactive radical intermediates taking place after the initial oxidation of the phenol-hydroxyl groups, we show that i) Laccase activity is able to catalyze bond cleavage in low molecular weight phenolic lignin...... model compounds; ii) For laccases to catalyze inter-unit bond cleavage in lignin substrates, the presence of a mediator system is required. Clearly, the higher the redox potential of the laccase enzyme, the broader the range of substrates, including o- and p-diphenols, aminophenols, methoxy...

  7. Extraction and quantitation of coumarin from cinnamon and its effect on enzymatic browning in fresh apple juice: a bioinformatics approach to illuminate its antibrowning activity.

    Science.gov (United States)

    Thada, Rajarajeshwari; Chockalingam, Shivashri; Dhandapani, Ramesh Kumar; Panchamoorthy, Rajasekar

    2013-06-05

    Enzymatic browning by polyphenoloxidase (PPO) affects food quality and taste in fruits and vegetables. Thus, the study was designed to reduce browning in apple juice by coumarin. The ethanolic extract of cinnamon was prepared and its coumarin content was quantitated by HPLC, using authentic coumarin (AC) as standard. The effect of cinnamon extract (CE) and AC on enzymatic browning, its time dependent effects, and the specific activity of PPO and peroxidase (POD) were studied in apple juice. The docking of coumarin with PPO and POD was also performed to elucidate its antibrowning mechanism. The CE (73%) and AC (82%) showed better reduction in browning, maintained its antibrowning effect at all time points, and significantly (p < 0.05) reduced the specific activity of PPO and POD when compared with controls. Coumarin showed strong interaction with binding pockets of PPO and POD, suggesting its potential use as inhibitor to enzyme mediated browning in apple juice.

  8. Tendências evolutivas de famílias produtoras de cumarinas em angiospermae Evolutionary tendency of coumarin-bearing families in angiospermae

    Directory of Open Access Journals (Sweden)

    Claudia Valeria Campos Ribeiro

    2002-07-01

    Full Text Available Coumarins are special metabolites well distributed in the Angiospermae, either in Monocotyledoneae or Dicotyledoneae. Simple coumarins, the most widespread type, is found in all coumarin-producing families, such as: Apiaceae, Rutaceae, Asteraceae, Fabaceae, Oleaceae, Moraceae e Thymelaeaceae. The other types, linear- and angular furanocoumarins, linear- and angular pyranocoumarins, lignocoumarins, bis- and triscoumarins, are of more restricted circumscription. Among the families with occurrence numbers (NO > 100, the more advanced ones are specialized in the production of only one or two coumarin types, while the primitive families are very well diversified in types. Calculations of percentual numbers of occurrence (%NO show relevant meaning of coumarin-types in the taxonomic positioning of the producing taxa.

  9. Quantification of coumarin in cinnamon and woodruff beverages using DIP-APCI-MS and LC-MS.

    Science.gov (United States)

    Krieger, Sonja; Hayen, Heiko; Schmitz, Oliver J

    2013-10-01

    The use of the direct inlet probe-atmospheric-pressure chemical ionization (DIP-APCI) ion source developed in our laboratory coupled to a high resolution Q-TOF MS for the quantitative analysis of coumarin in different cinnamon samples was demonstrated in this study. Extraction of coumarin from various cinnamon samples was followed by DIP-APCI-mass spectrometry (MS) and liquid chromatography (LC)-MS analysis. For quantification, an external calibration with and without the use of stable isotope-labeled coumarin as internal standard was compared. The results obtained by DIP-APCI-MS and LC-MS were in good agreement. Even without the use of an internal standard satisfying linearity (R(2) > 0.997), recovery (94-104% for spiking levels between 100 and 5,000 mg/kg) and intra- and interday repeatability (2.2-13.8%RSD) was demonstrated using DIP-APCI-MS. To reduce the number of samples requiring quantitative analysis, the possibility of semi-quantitative screening of coumarin directly from powdered cinnamon using DIP-APCI-MS was shown. The analysis of woodruff-flavored beverages and cinnamon-flavored chewing gum by DIP-APCI-MS resulted in the formation of an artifact interfering with coumarin detection. As with other ambient ionization methods, special attention has to be paid to possible spectral interferences due to isobaric substances present in the sample matrix or formed from matrix components after ionization. The temperature-programmed vaporization in DIP-APCI-MS combined with the use of stable isotope-labeled coumarin as internal standard helped in recognizing this interference.

  10. The influence of naphthaleneacetic acid (NAA) and coumarin on flavonoid production by fungus Phellinus sp.: modeling of production kinetic profiles.

    Science.gov (United States)

    Ma, Xiao-Kui; Li, Le; Peterson, Eric Charles; Ruan, Tingting; Duan, Xiaoyi

    2015-11-01

    For the purpose of improving the fungal production of flavonoids, the influence of naphthaleneacetic acid (NAA) and coumarin on flavonoid production by fungus Phellinus sp. P0988 was investigated by developing the corresponding kinetics of flavonoid production in a 7-L bioreactor. Phellinus sp. was confirmed to form flavonoids in pellets and broth when cultivated in basic medium, and the optimum concentration of NAA and coumarin in medium for flavonoid production were determined to be 0.03 and 0.02 g/L, respectively. The developed unstructured mathematical models were in good agreement with the experimental results with respect to flavonoid production kinetic profiles with NAA and coumarin supplementation at optimum levels and revealed significant accuracy in terms of statistical consistency and robustness. Analysis of these kinetic processes indicated that NAA and coumarin supplementations imposed a stronger positive influence on flavonoid production and substrate consumption compared to their effects on cell growth. The separate addition of NAA and coumarin resulted in enhancements in final product accumulation and productivity, achieving final flavonoid concentrations of 3.60 and 2.75 g/L, respectively, and glucose consumption showed a significant decrease compared to the non-supplemented control as well. Also, the separate presence of NAA and coumarin respectively decreased maintenance coefficients (M s) from 2.48 in the control to 1.39 and 0.22, representing decreases of 43.9 and 91.1 %, respectively. The current study is the first known application of mathematical kinetic models to explore the influence of medium components adding on flavonoid production by fungi.

  11. A high-light-harvesting-efficiency coumarin dye for stable dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Z.S.; Cui, Y.; Hara, K. [National Institute of Advanced Industrial, Science and Technology (AIST), Tsukuba, Ibaraki (Japan); Dan-oh, Y.; Kasada, C.; Shinpo, A. [Hayashibara Biochemical Laboratories, Inc., Okayama (Japan)

    2007-04-20

    A new coumarin dye for use in dye-sensitized solar cells (DSSCs) is reported. It exhibits near-unity light harvesting efficiency and incident photon-to-electron conversion efficiency over a wide spectral region in 6 {mu}m transparent TiO{sub 2} films. DSSCs based on this metal-free organic dye show long-term stability and power-conversion efficiencies of around 6 % under continuous light-soaking stress for up to 1000 h. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  12. DFT study and microbiology of some coumarin-based compounds containing a chalcone moiety

    Directory of Open Access Journals (Sweden)

    Špirtović-Halilović Selma

    2014-01-01

    Full Text Available In the present investigation, a series of coumarin-based compounds containing a chalcone moiety were studied for their in vitro and in silico properties. DFT global chemical reactivity descriptors (chemical hardness, total energy, electronic chemical potential and electrophilicity are calculated for four synthesized compounds and used to predict their relative stability and reactivity. The antibacterial activities of all compounds have been screened against Bacillus subtilis (ATCC No. 6633 and Bacillus cereus (ATCC No. 11778. Quantum-chemical calculations indicate that antibacterial activity correlates well with chemical reactivity descriptors of molecules.

  13. Prenylated Coumarins from Heracleum stenopterum, Peucedanum praeruptorum, Clausena lansium, and Murraya paniculata

    Directory of Open Access Journals (Sweden)

    Xiang-Mei Li

    2016-09-01

    Full Text Available Abstract Four hitherto unknown prenylated coumarins, namely 6″-O-β-d-apiofuranosylapterin (1, 4′-O-isobutyroylpeguangxienin (2, 6-(3-methyl-2-oxobutyroyl-7-methoxycoumarin (3, and 6-hydroxycoumurrayin (4, were isolated from the ethanol extract of Heracleum stenopterum, Peucedanum praeruptorum, Clausena lansium, and Murraya paniculata, respectively. Their chemical structures were established on the basis of extensive spectroscopic analysis. Compound 2 exhibited in vitro cytotoxic activity against five human cancer cell lines (HL-60, A-549, SMMC-7721, MCF-7, and SW-480 with IC50 values ranging from 15.9 to 23.2 μM. Graphical Abstract

  14. New Coumarins and Anti-Inflammatory Constituents from the Fruits of Cnidium monnieri

    OpenAIRE

    Lee, Tzong-Huei; Chen, Yuan-Chih; Hwang, Tsong-Long; Shu, Chih-Wen; Sung, Ping-Jyun; Lim, Yun-Ping; Kuo, Wen-Lung; Chen, Jih-Jung

    2014-01-01

    The fruit of Cnidium monnieri is commercially used as healthcare products for the improvement of impotence and skin diseases. Three new coumarins, 3'-O-methylmurraol (1), rel-(1'S,2'S)-1'-O-methylphlojodicarpin (2), and (1'S,2'S)-1'-O-methylvaginol (3), have been isolated from the fruits of C. monnieri, together with 14 known compounds (4–17). The structures of these new compounds were determined through spectroscopic and MS analyses. Compounds 1, 4–12, and 14–17 exhibited inhibition (IC50 ≤...

  15. Antimicrobial activity of some coumarin containing herbal plants growing in Finland.

    Science.gov (United States)

    Ojala, T; Remes, S; Haansuu, P; Vuorela, H; Hiltunen, R; Haahtela, K; Vuorela, P

    2000-11-01

    Antimicrobial screening against selected Gram-positive and Gram-negative bacteria, yeasts, mold, as well as plant pathogenic fungi, with emphasis on method optimization was carried out on methanol extracts prepared from seven plants grown in Finland. Sensitivity to the extracts was found to vary considerably among the micro-organisms, the extract from Petroselinum crispum and Ruta graveolens showing the highest toxicity against Rhizoctonia solani. The growth of Heterobasidium annosum was inhibited, whereas that of Phytophtora (cactorum) was promoted by all the extracts. The antibacterial and antifungal activities of six natural coumarin compounds were weak, except for the inhibitory effect against Fusarium culmorum.

  16. Coumarin Antifungal Lead Compounds from Millettia thonningii and Their Predicted Mechanism of Action

    Directory of Open Access Journals (Sweden)

    Daniel M. Ayine-Tora

    2016-10-01

    Full Text Available Fungal pathogens continue to pose challenges to humans and plants despite efforts to control them. Two coumarins, robustic acid and thonningine-C isolated from Millettia thonningii, show promising activity against the fungus Candida albicans with minimum fungicidal concentration of 1.0 and 0.5 mg/mL, respectively. Molecular modelling against the putative bio-molecular target, lanosterol 14α-demethylase (CYP51, revealed a plausible binding mode for the active compounds, in which the hydroxyl group binds with a methionine backbone carboxylic group blocking access to the iron catalytic site. This binding disrupts the synthesis of several important sterols for the survival of fungi.

  17. Synthesis of modified pyridine and bipyridine substituted coumarins as potent antimicrobial agents

    Directory of Open Access Journals (Sweden)

    Lad Hemali B.

    2015-01-01

    Full Text Available In search for new antimicrobial agents a series of new modified pyridine and bipyridine substituted coumarins 5a-y was designed and synthesized by adopting molecular hybridization strategy. All the synthesized compounds were evaluated for their in vitro antimicrobial activity using broth dilution method against selected bacterial (Gram-positive and Gram-negative and fungal strains. Compounds 5a, 5f, 5g, 5n, 5r, 5t, 5w, 5x and 5y demonstrated promising antibacterial activity while other derivatives showed comparable activity to standard drugs used as reference.

  18. Biosynthesis of coumarin glycosides by transgenic hairy roots of Polygonum multiflorum.

    Science.gov (United States)

    Zhou, Liangbin; Tian, Tian; Xue, Bailin; Song, Liyan; Liu, Ling; Yu, Rongmin

    2012-01-01

    To investigate the substrate specificity and regio-selectivity of coumarin glycosyltransferases in transgenic hairy roots of Polygonum multiflorum, esculetin (1) and eight hydroxycoumarins (2-9) were employed as substrates. Nine corresponding glycosides (10-18) involving four new compounds, 6-chloro-4-methylcoumarin 7-O-β-D-glucopyranoside (15), 6-chloro-4-phenylcoumarin 7-O-β-D-glucopyranoside (16), 8-hydroxy-4-methylcoumarin 7-O-β-D-glucopyranoside (17), and 8-allyl-4-methylcoumarin 7-O-β-D-glucopyranoside (18), were biosynthesized by the hairy roots.

  19. Quinones and coumarins from Ajania salicifolia and their radical scavenging and cytotoxic activity.

    Science.gov (United States)

    Wu, Hong-Ru; Zhang, Wei; Pang, Xiao-Yan; Gong, Yuan; Obulqasim, Xian Muxinuer U; Li, Hong-Fang; Zhu, Ying

    2015-01-01

    1,4-Naphthoquinone (1) and a new coumarin (3) were isolated from Ajania salicifolia, together with two known compounds (2, 4). The structures and stereochemistry of new compounds were elucidated using spectroscopic methods. Two compounds exhibited potent ABTS cation radical scavenging activities with IC50 values ranging 7.97-8.44 μM. Two quinones (1, 2) exhibited moderate cytotoxic activity against the human cancer cell lines (Hela, HepG2, and K562) with IC50 values of 11.24-35.15 μM in vitro. This is the first report of naphthoquinone in the genus Ajania.

  20. Coumarins from Daphne feddei and their potential anti-inflammatory activities.

    Science.gov (United States)

    Liang, Shuang; Feng, Yi; Tian, Jun-Mian; Lu, Min; Xiong, Zhi; Zhang, Wei-Dong

    2011-12-01

    Chemical examination of the methanolic extract from the stem bark of Daphne feddei led to the isolation of three new dicoumarin glucosides (1-3), and eight known coumarins, dicoumarins and dicoumarin glucosides. Their structures were elucidated by extensive analysis of spectral data and comparison with the literature values. All compounds were tested for inhibitory activity against lipopolysaccharide-induced NO production in RAW 264.7 macrophages, and compounds 4 and 5 showed potent inhibitory activity with IC₅₀ values of 0.161 and 0.127 μM, respectively.

  1. Two Cytotoxic Coumarin Glycosides from the Aerial Parts of Diceratella elliptica (DC. Jonsell Growing in Egypt

    Directory of Open Access Journals (Sweden)

    Mona M. Marzouk

    2012-03-01

    Full Text Available Two new coumarin glycosides, 6-methoxy-5,7-dihydroxy-3,4-dihydrocoumarin-8-C-glucopyranoside (1 and 5-vinyl-6,7-dimethoxy-3,4-dihydrocoumarin-8-C-glucopyranoside (2, along with four known flavonoid compounds, were isolated from the aerial parts of Diceratella elliptica (DC. Jonsell growing in Egypt. Their structures were established on the basis of detailed chromatographic and spectroscopic techniques (UV, 1D NMR, 2D NMR, and ESIMS. Compounds 1 and 2 were evaluated for their cytotoxic activity and showed relatively high activity against three human carcinoma cell lines; liver (HEPG2, cervix (HELA and colon (HCT116.

  2. Preparation and evaluation of a coumarin library towards the inhibitory activity of the enzyme gGAPDH from Trypanosoma cruzi

    Energy Technology Data Exchange (ETDEWEB)

    Alvim Junior, Joel; Dias, Ricardo L.A.; Correa, Arlene G. [Universidade Federal de Sao Carlos, SP (Brazil). Dept. de Quimica]. E-mail: agcorrea@power.ufscar.br; Castilho, Marcelo S.; Oliva, Glaucius [Sao Paulo Univ., Sao Carlos, SP (Brazil). Inst. de Fisica

    2005-07-15

    Chagas' disease, caused by Trypanosoma cruzi, is endemic in 15 countries in Latin America. In this work a library of 38 coumarins was prepared in solution phase and evaluated against T. cruzi glycolytic enzyme glyceraldehyde-3-phosphate-dehydrogenase (gGAPDH). The synthetic route was based on the Knoevenagel condensation of different 2-hydroxybenzaldehydes with Meldrum's acid or diethyl malonate, followed by O-alkylation and/or transesterification reactions. Among the prepared coumarins, the best values obtained to inhibit 50% of the enzymatic activity range from 80 to 130 {mu}M. (author)

  3. Stabilization of AuNPs by monofunctional triazole linked to ferrocene, ferricenium, or coumarin and applications to synthesis, sensing, and catalysis.

    Science.gov (United States)

    Li, Na; Zhao, Pengxiang; Igartua, María E; Rapakousiou, Amalia; Salmon, Lionel; Moya, Sergio; Ruiz, Jaime; Astruc, Didier

    2014-11-03

    Monofunctional triazoles linked to ferrocene, ferricenium, or coumarin (Cou), easily synthesized by copper-catalyzed azide alkyne (CuAAC) "click" reactions between the corresponding functional azides and (trimethylsilyl)acetylene followed by silyl group deprotection, provide a variety of convenient neutral ligands for the stabilization of functional gold nanoparticles (AuNPs) in polar organic solvents. These triazole (trz)-AuNPs are very useful toward a variety of applications to synthesis, sensing, and catalysis. Both ferrocenyl (Fc) and isostructural ferricenium linked triazoles give rise to AuNP stabilization, although by different synthetic routes. Indeed, the first direct synthesis and stabilization of AuNPs by ferricenium are obtained by the reduction of HAuCl4 upon reaction with a ferrocene derivative, AuNP stabilization resulting from a synergy between electrostatic and coordination effects. The ferricenium/ferrocene trz-AuNP redox couple is fully reversible, as shown by cyclic voltammograms that were recorded with both redox forms. These trz-AuNPs are stable for weeks in various polar solvents, but at the same time, the advantage of trz-AuNPs is the easy substitution of neutral trz ligands by thiols and other ligands, giving rise to applications. Indeed, this ligand substitution of trz at the AuNP surface yields a stable Fc-terminated nanogold-cored dendrimer upon reaction with a Fc-terminated thiol dendron, substitution of Cou-linked trz with cysteine, homocysteine, and glutathione provides remarkably efficient biothiol sensing, and a ferricenium-linked trz-AuNP catalyst is effective for NaBH4 reduction of 4-nitrophenol to 4-aminophenol. In this catalytic example, the additional electrostatic AuNP stabilization modulates the reaction rate and induction time.

  4. [Effect investigation of coumarin constituents in Angelica dahurica on pharmacokinetics of docetaxel by LC-MS].

    Science.gov (United States)

    Guan, Yong-Mei; Zhu, Wei-Feng; Guan, Xue-Jing; Liao, Zheng-Gen; Zhao, Guo-Wei; Dong, Wei; Liang, Xin-Li

    2017-12-01

    The study was aimed to establish a liquid chromatography-tandem mass spectrometric method for the determination of the docetaxel concentration in rat plasma, and study the effect of coumarin constituents (imperatorin, isoimperatorin and oxypeucedanin) in Angelica dahurica on pharmacokinetics of docetaxel.Plasma was precipitated with acetonitrile and determined by LC-MS method with Paclitaxel as an internal standard. The specificity, linearity, range, accuracy, precision and stability of the method were suitable for the determination of docetaxel in plasma.Six sprague-dawley rats in each group received intragastric administration of docetaxel (50 mg•kg⁻¹), oxypeucedanin (8 mg•kg⁻¹) combined with docetaxel (50 mg•kg⁻¹), imperatorin (15 mg•kg⁻¹) combined with docetaxel (50 mg•kg⁻¹), and isoimperatorin(15 mg•kg⁻¹) combined with docetaxel (50 mg•kg⁻¹).Their drug plasma concentration was determined by LC-MS with Paclitaxel as an internal standard to draw plasma concentration-time curve, and the phamacokinetic parameters were calculated by DAS 2.0. The results showed that the phamacokinetic parameters of docetaxel all had notable changes when combined with imperatorin, isoimperatorin, and oxypeucedanin, respectively. The phamacokinetic parameters AUC and Cmax were significantly increased, indicating that coumarin constituents in Angelica dahurica could promote the oral bioavailability of docetaxel, and their effects were in the following order: oxypeucedanin> isoimperatorin> imperatorin. Copyright© by the Chinese Pharmaceutical Association.

  5. Synthesis and application of a highly selective copper ions fluorescent probe based on the coumarin group

    Science.gov (United States)

    He, Guangjie; Liu, Xiangli; Xu, Jinhe; Ji, Liguo; Yang, Linlin; Fan, Aiying; Wang, Songjun; Wang, Qingzhi

    2018-02-01

    A highly selective copper ions fluorescent probe based on the coumarin-type Schiff base derivative 1 (probe) was produced by condensation reaction between coumarin carbohydrazide and 1H-indazole-3-carbaldehyde. The UV-vis spectroscopy showed that the maximum absorption peak of compound 1 appeared at 439 nm. In the presence of Cu2 + ions, the maximum peak decreased remarkably compared with other physiological important metal ions and a new absorption peak at 500 nm appeared. The job's plot experiments showed that complexes of 1:2 binding mode were formed in CH3CN:HEPES (3:2, v/v) solution. Compound 1 exhibited a strong blue fluorescence. Upon addition of copper ions, the fluorescence gradually decreased and reached a plateau with the fluorescence quenching rate up to 98.73%. The detection limit for Cu2 + ions was estimated to 0.384 ppm. Fluorescent microscopy experiments demonstrated that probe 1 had potential to be used to investigate biological processes involving Cu2 + ions within living cells.

  6. Natural history and management of cervical spine disease in chondrodysplasia punctata and coumarin embryopathy.

    Science.gov (United States)

    Vogel, Timothy W; Menezes, Arnold H

    2012-04-01

    Chondrodysplasia punctata (CDP) is a group of skeletal dysplasias manifesting with progressive cervical instability that leads to neurological deficits and eventual death. The major clinical features of CDP also present in a phenocopy known as coumarin embryopathy (CE) which results from coumarin exposure during pregnancy. The objective of this study was to assess treatment strategies employed for children affected by CDP or CE with cervical instability and to determine a strategy on how best to diagnose and treat affected neonates. We performed a systematic review of the English literature for cases reporting cervical spine involvement in CDP and CE and identified 44 such patients. We extracted clinical information on these disorders and identified two patients from our craniovertebral junction database of over 6,000 patients evaluated at our institution. Patients most frequently present with hyperreflexia (21%) and weakness (21%), and there were various conservative treatment strategies. Twenty-one percent of patients who were treated conservatively had neurological complications in their clinical course. There were two deaths reported, one resulting from conservative treatment and one from surgical treatment. We also report long-term follow-up analysis for a patient treated at our institution for the last 30 years and agree with all other reports that suggest that monitoring patients for neurological changes is essential to prevent further neurological injury. This study emphasizes the need for careful neurological and surgical evaluation of pediatric patients with cervical spine abnormalities affected by CDP or CE in order to prevent progressive instability.

  7. Quantitative structure-cytotoxicity relationship analysis of coumarin and its derivatives by semiempirical molecular orbital method.

    Science.gov (United States)

    Ishihara, Mariko; Yokote, Yoshiko; Sakagami, Hiroshi

    2006-01-01

    A semiempirical molecular orbital method (CAChe) was applied to delineate the relationship between cytotoxicity against the human squamous cell carcinoma line HSC-2 (evaluated by 50% cytotoxic concentration, CC50) of 20 coumarin (2H-pyran-2-one) derivatives and twelve physical parameters (descriptors) calculated by the CONFLEX/PM3 method. There was a highly significant correlation between the CC50 and ionization potential, highest occupied molecular orbital (HOMO) energy, difference between electron energy of HOMO and electron energy of lowest unoccupied molecular orbital (LUMO), or absolute hardness (r2=0.756 - 0.802). On the other hand, there was no significant correlation between the CC50 and heat of formation, stability of hydration, dipole moment, electron affinity, or LUMO energy (r2=0.13.- 0.36). When the CC50 was plotted vs. log P, a parabolic curve was produced, with a maximum cytotoxicity (or the least CC50 value) at log P of 2.5. The present study demonstrated that hardness and softness, other than the electron accepting and donating properties, are important factors in estimating the cytotoxic activity of coumarin derivatives.

  8. Modulation of the antibiotic activity against multidrug resistant strains of coumarins isolated from Rutaceae species.

    Science.gov (United States)

    Madeiro, Sara A L; Borges, Nathalie H P B; Souto, Augusto L; de Figueiredo, Pedro T R; Siqueira-Junior, José P; Tavares, Josean F

    2017-03-01

    The first occurrences and dissemination of resistant microorganisms led to the inefficacy of many antibiotics, available in the market nowadays, therefore, the search for new substances with antimicrobial activity from natural sources has gained a great importance. The purpose of this work is to evaluate the antibacterial activity and modulation of drug resistance in Staphylococcus aureus by coumarins such as bergapten, xantotoxin, isopimpinellin and imperatorin obtained from two Rutaceae species (Metrodorea mollis and Pilocarpus spicatus). The antimicrobial activity was assessed based on the minimum inhibitory concentration (MIC), using the microdilution method. The MIC was >256 g/mL for all coumarins tested. Regarding the modulation of drug resistance assay, the isopimpinellin reducted the MIC of erytromicin by 4 times, whereas imperatorin exhibited the best result, reducing the MIC of tetracycline (2 times), erytomicin (4 times) and norfloxacin (4 times). By reducing the MIC of ethidium bromide, the imperatorin is consider in fact, as a putative efflux pump inhibitor of bacteria. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. NorA efflux pump inhibitory activity of coumarins from Mesua ferrea.

    Science.gov (United States)

    Roy, Somendu K; Kumari, Neela; Pahwa, Sonika; Agrahari, Udai C; Bhutani, Kamlesh K; Jachak, Sanjay M; Nandanwar, Hemraj

    2013-10-01

    The purpose of this investigation was to study the modulator and efflux pump inhibitor activity of coumarins isolated from Mesua ferrea against clinical strains as well as NorA-over expressed strain of Staphylococcus aureus 1199B. Seven coumarins were tested for modulator activity using ethidium bromide (EtBr) as a substrate. Compounds 1, 4-7 modulated the MIC of EtBr by ≥ 2 fold against wild type clinical strains of S. aureus 1199 and S. aureus 1199B, whereas compounds 4-7 modulated the MIC of EtBr by ≥ 16 fold against MRSA 831. Compounds 1, 4-7 also reduced the MIC of norfloxacin by ≥ 8 fold against S. aureus 1199B, and 4-6 reduced the MIC of norfloxacin by ≥ 8 fold against MRSA 831 at half of their MICs. Inhibition of EtBr efflux by NorA-overproducing S. aureus 1199B and MRSA 831 confirmed the role of compounds 4-6 as NorA efflux pump inhibitors (EPI). Dose-dependent activity at sub-inhibitory concentration (6.25 μg/mL) suggested that compounds 4 and 5 are promising EPI compared to verapamil against 1199B and MRSA 831 strains. © 2013.

  10. Vanadium-catalyzed deoxydehydration of glycols.

    Science.gov (United States)

    Chapman, Garry; Nicholas, Kenneth M

    2013-09-25

    A survey of several metavandate (VO3(-)) and chelated dioxovanadium derivatives shows that tetrabutylammonium dioxovanadium(V)dipicolinate most effectively catalyzes the deoxydehydration (DODH) of glycols to olefins in moderate to excellent yields with triphenylphosphine or sodium sulfite as reductants.

  11. Rapid Identification of Coumarins from Micromelum falcatum by UPLC-HRMS/MS and Targeted Isolation of Three New Derivatives

    Directory of Open Access Journals (Sweden)

    Eirini Kouloura

    2014-09-01

    Full Text Available Micromelum falcatum, a medicinal plant of the Rutaceae family, has been used in the Traditional Chinese Medicine (TCM mainly against colds and rheumatoid arthritis. Despite its traditional use the association of its constituents with possible anti-inflammatory activity has not been explored. During this study, a rapid UPLC-ESI(+-HRMS method was developed for the profiling of M. falcatum leave extracts and the targeted isolation of coumarin constituents. Based on chromatographic, spectroscopic and spectrometric features several 7-oxygenated coumarin derivatives were detected. After targeted isolation, eight coumarins, among them three new natural products, namely microfalcrin, microcoumaririn and micromelosidester, were purified using semi-preparative HPLC and unambiguously identified by 1 and 2D NMR. Furthermore, important spectrometric characteristics were revealed based on the HRMS and HRMS/MS spectra of the isolated 7-oxygenated coumarins facilitating their identification in complex mixtures. Finally, the anti-inflammatory properties of the extracts and representative compounds were evaluated by measuring the inhibition of the pro-inflammatory mediator NF-κB induction and nitric oxide (NO production.

  12. Solvent Effects on Emission Yield and Lifetime for Coumarin Laser Dyes. Requirements for a Rotatory Decay Mechanism.

    Science.gov (United States)

    1983-10-31

    mothyl > R - hydrogen); (4) a diminished tendency toward non-radiative decay for NH2 - (j) and Ni- subsituted dyes with additional ortho ring...argue against a major role for electron photoejeotion from excited coumarin singlets, despite the fact that the solvated electron may be a product of

  13. Pressurized Liquid Extraction of Coumarins from Fruits of Heracleum leskowii with Application of Solvents with Different Polarity under Increasing Temperature

    Directory of Open Access Journals (Sweden)

    Krystyna Skalicka-Woźniak

    2012-04-01

    Full Text Available Coumarins are nowadays an important group of organic compounds from natural sources that are useful in a number of fields. Because they possess different pharmacological properties, finding the proper extraction conditions for their separation from plant matrices is a very important step. In this report Pressurized Liquid Extraction (PLE under different temperature conditions and with different types of extraction solvents were tested. As a matrix, fruits of Heracleum leskowii have been used. A simple reverse phase high-performance liquid chromatographic method (RP-HPLC coupled with a photodiode array detector (DAD has been developed for separation and quantitative analysis of the main coumarins. Umbelliferone, xanthotoxin, angelicin, isopimpinellin, bergapten, imperatorin and isoimperatorin were investigated. Bergapten and imperatorin were dominant in almost all extracts in the range of 9.92 ± 0.02–20.93 ± 0.06 and 12.19 ± 0.98–19.07 ± 0.03 mg/100 g, respectively. Dichloromethane and methanol were chosen as the most proper suitable solvents for extraction of coumarins. By increasing the temperature the amount of extracted coumarins increases in petroleum ether and dichloromethane extracts.

  14. Rapid identification of coumarins from Micromelum falcatum by UPLC-HRMS/MS and targeted isolation of three new derivatives.

    Science.gov (United States)

    Kouloura, Eirini; Danika, Eirini; Kim, Sothea; Hoerlé, Mélanie; Cuendet, Muriel; Halabalaki, Maria; Skaltsounis, Leandros A

    2014-09-19

    Micromelum falcatum, a medicinal plant of the Rutaceae family, has been used in the Traditional Chinese Medicine (TCM) mainly against colds and rheumatoid arthritis. Despite its traditional use the association of its constituents with possible anti-inflammatory activity has not been explored. During this study, a rapid UPLC-ESI(+)-HRMS method was developed for the profiling of M. falcatum leave extracts and the targeted isolation of coumarin constituents. Based on chromatographic, spectroscopic and spectrometric features several 7-oxygenated coumarin derivatives were detected. After targeted isolation, eight coumarins, among them three new natural products, namely microfalcrin, microcoumaririn and micromelosidester, were purified using semi-preparative HPLC and unambiguously identified by 1 and 2D NMR. Furthermore, important spectrometric characteristics were revealed based on the HRMS and HRMS/MS spectra of the isolated 7-oxygenated coumarins facilitating their identification in complex mixtures. Finally, the anti-inflammatory properties of the extracts and representative compounds were evaluated by measuring the inhibition of the pro-inflammatory mediator NF-κB induction and nitric oxide (NO) production.

  15. Biodiesel production by enzyme-catalyzed transesterification

    OpenAIRE

    Stamenković Olivera S.; Lazić Miodrag L.; Veljković Vlada B.; Skala Dejan U.

    2005-01-01

    The principles and kinetics of biodiesel production from vegetable oils using lipase-catalyzed transesterification are reviewed. The most important operating factors affecting the reaction and the yield of alkyl esters, such as: the type and form of lipase, the type of alcohol, the presence of organic solvents, the content of water in the oil, temperature and the presence of glycerol are discussed. In order to estimate the prospects of lipase-catalyzed transesterification for industrial appli...

  16. Supercritical CO2 Extraction of Lavandula angustifolia Mill. Flowers: Optimisation of Oxygenated Monoterpenes, Coumarin and Herniarin Content.

    Science.gov (United States)

    Jerković, Igor; Molnar, Maja; Vidović, Senka; Vladić, Jelena; Jokić, Stela

    2017-11-01

    Lavandula angustifolia is good source of oxygenated monoterpenes containing coumarins as well, which are all soluble in supercritical CO2 (SC-CO2 ). The study objective is to investigate SC-CO2 extraction parameters on: the total yield; GC-MS profile of the extracts; relative content of oxygenated monoterpenes; the amount of coumarin and herniarin; and to determine optimal SC-CO2 extraction conditions by response surface methodology (RSM). SC-CO2 extraction was performed under different pressure, temperature and CO2 flow rate determined by Box-Behnken design (BBD). The sample mass and the extraction time were kept constant. The chemical profiles and relative content of oxygenated monoterpenes (as coumarin equivalents, CE) were determined by GC-MS. Coumarin and herniarin concentrations were dosed by HPLC. SC-CO2 extracts contained linalool (57.4-217.9 mg CE/100 g), camphor (10.6-154.4 mg CE/100 g), borneol (6.2-99.9 mg CE/100 g), 1,8-cineole (5.0-70.4 mg CE/100 g), linalyl acetate (86.1-267.9 mg CE/100 g), coumarin (0.95-18.16 mg/100 g), and herniarin (0.95-13.63 mg/100 g). The interaction between the pressure and CO2 flow rate as well as between the temperature and CO2 flow rate showed statistically significant influence on the extraction yield. Applying BBD, the optimum extraction conditions for higher monoterpenes and lower coumarin content were at 10 MPa, 41°C and CO2 flow rate 2.3 kg/h, and at 30 MPa, 50°C and CO2 flow rate 3 kg/h for higher monoterpenes and coumarin content. SC-CO2 extraction is a viable technique for obtaining lavender extracts with desirable flavour components. The second-order model based on BBD predicts the results for SC-CO2 extraction quite satisfactorily. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  17. Transition-metal catalyzed synthesis of Ketoprofen

    Directory of Open Access Journals (Sweden)

    Ramminger Carolina

    2000-01-01

    Full Text Available Transition metal-catalyzed reactions including carbonylations, hydrovinylations and hydrogenations have been applied in the synthesis of alpha-(3-benzoylphenylpropanoic acid (Ketoprofen. 3-Vinylbenzophenone was obtained from 3-bromobenzophenone by a Pd-catalyzed Heck coupling reaction. Pd-catalyzed carbonylation of this olefin gave the isopropyl alpha-(3-benzoylphenyl propionate in high yield (95% and with high regioselectivity (>99.5%. Ketoprofen was obtained in 90% yield by hydrolysis of the isopropyl ester. It was also obtained in two steps from 3-vinylbenzophenone by a Ni-catalyzed hydrovinylation selectively affording 3-(3'-benzoylphenyl-1-butene, followed by an oxidation. 3-Ethynylbenzophenone was obtained from 3-bromobenzophenone by Pd-catalyzed coupling reaction. By means of a Pd-catalyzed carbonylation, this alkyne was converted regioselectively (97% into methyl alpha-(3-benzoylphenyl acrylate (93% yield. Hydrolysis of the ester afforded the alpha-(3-benzoylphenylacrylic acid. Asymmetric hydrogenation of this acid to give (S-ketoprofen in 95% optical yield was achieved using a chiral Ru-(S-BINAP catalyst.

  18. Concise synthesis of anti-HIV-1 active (+)-inophyllum B and (+)-calanolide A by application of (-)-quinine-catalyzed intramolecular oxo-Michael addition.

    Science.gov (United States)

    Sekino, Etsuko; Kumamoto, Takuya; Tanaka, Tomohiro; Ikeda, Tomoko; Ishikawa, Tsutomu

    2004-04-16

    (-)-Quinine-catalyzed intramolecular oxo-Michael addition (IMA) of 7-hydroxy-5-methoxy-8-tigloylcoumarins was developed for the enantioselective construction of 2,3-dimethyl-4-chromanone systems in the context of the asymmetric synthesis of anti-HIV-1 active Calophyllum coumarins. Combination of the IMA and MgI(2)-assisted demethylation of the 5-methoxy group along with isomerization of the formed chromanone systems as key steps successfully led to the concise synthesis of (+)-inophyllum B and (+)-calanolide A, possible candidates for AIDS drugs. Further examination of the asymmetric IMA with cinchona alkaloids lacking a methoxy group on the quinoline skeleton suggested the influence of the methoxy substituent on stereoselectivity at the stereogenic centers of the chromanone systems.

  19. Anti-inflammatory terpenylated coumarins from the leaves of Zanthoxylum schinifolium with α-glucosidase inhibitory activity.

    Science.gov (United States)

    Nguyen, Phi-Hung; Zhao, Bing Tian; Kim, Okhwa; Lee, Jeong Hyung; Choi, Jae Sue; Min, Byung Sun; Woo, Mi Hee

    2016-04-01

    Nine terpenylated coumarins, namely 7-[(E)-3',7'-dimethyl-6'-oxo-2',7'-octadienyl]oxy-coumarin (1), schinilenol (2), schinindiol (3), collinin (4), 7-[(E)-7'-hydroxy-3',7'-dimethy-locta-2',5'-dienyloxy]-coumarin (5), 8-methoxyanisocoumarin (6), 7-(6'R-hydroxy-3',7'-dimethyl-2'E,7'-octadienyloxy)coumarin (7), (E)-4-methyl-6-(coumarin-7'-yloxy)hex-4-enal (8), and aurapten (9), along with a 4-quinolone alkaloid (10) and integrifoliodiol (11), were isolated from the leaves of Zanthoxylum schinifolium. Of the isolates, compounds 4 and 7 potentially inhibited NO production in lipopolysaccharide (LPS)-stimulated macrophage RAW264.7 cells, with IC50 values of 5.9 ± 0.8 and 18.2 ± 1.8 μM, respectively. Furthermore, compounds 4 and 7 dose-dependently reduced the LPS-induced iNOS expression. Moreover, pre-incubation of cells with 4 and 7 significantly suppressed LPS-induced COX-2 protein expression. In addition, compounds 4, 7, 8, and 10 showed strong α-glucosidase inhibitory effects, with IC50 values of 92.1 ± 0.7, 90.6 ± 0.9, 78.2 ± 0.2, and 82.4 ± 0.8 μM, respectively. Compounds 1, 5, and 11 displayed moderate effects with IC50 values of 161.6 ± 0.3, 164.4 ± 1.1, and 155.4 ± 0.9 μM, while acarbose, a positive control, possessed an IC50 value of 121.5 ± 1.0 μM. This is the first investigation on the α-glucosidase inhibitory effect of components from Zanthoxylum schinifolium. Further studies should be made on active compounds.

  20. Simultaneous Determination of Coumarin and Its Derivatives in Tobacco Products by Liquid Chromatography-Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Zhiqin Ren

    2016-11-01

    Full Text Available In this paper an analytical method based on high performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS for the determination of coumarin and its derivatives in tobacco products was developed. The MS/MS fragmentation pathways of the eight coumarins were elucidated. The new analytical method was defined based on two main axes, an extraction procedure with acetonitrile and analyte detection performed by HPLC-MS/MS in electron impact mode. The excellent selectivity and sensitivity achieved in multiple reaction monitoring (MRM mode allowed satisfactory confirmation and quantitation for the coumarin flavor additives. Under the optimized gradient elution conditions, it took only 4.5 min to separate all eight coumarins. Good linearity for all the analytes were confirmed by the correlation coefficient r2, ranging from 0.9987 to 0.9996. The limits of detection (LODs and limits of quantitation (LOQs of these compounds were in the range of 0.5–1.7 μg/kg and 1.7–5.2 μg/kg, respectively. The average recoveries at three spiked levels (LOQ, 1.5LOQ, 2LOQ were all in the range of 69.6%–95.1% with RSDs (n = 6 lower than 5.3%. The method of HPLC-MS/MS developed in this study was initially applied to the research of coumarin flavor additives in tobacco products collected from the located market in Beijing from China and proved to be accurate, sensitive, convenient and practical.

  1. In silico genotoxicity of coumarins: application of the Phenol-Explorer food database to functional food science.

    Science.gov (United States)

    Guardado Yordi, E; Matos, M J; Pérez Martínez, A; Tornes, A C; Santana, L; Molina, E; Uriarte, E

    2017-08-01

    Coumarins are a group of phytochemicals that may be beneficial or harmful to health depending on their type and dosage and the matrix that contains them. Some of these compounds have been proven to display pro-oxidant and clastogenic activities. Therefore, in the current work, we have studied the coumarins that are present in food sources extracted from the Phenol-Explorer database in order to predict their clastogenic activity and identify the structure-activity relationships and genotoxic structural alerts using alternative methods in the field of computational toxicology. It was necessary to compile information on the type and amount of coumarins in different food sources through the analysis of databases of food composition available online. A virtual screening using a clastogenic model and different software, such as MODESLAB, ChemDraw and STATISTIC, was performed. As a result, a table of food composition was prepared and qualitative information from this data was extracted. The virtual screening showed that the esterified substituents inactivate molecules, while the methoxyl and hydroxyl substituents contribute to their activity and constitute, together with the basic structures of the studied subclasses, clastogenic structural alerts. Chemical subclasses of simple coumarins and furocoumarins were classified as active (xanthotoxin, isopimpinellin, esculin, scopoletin, scopolin and bergapten). In silico genotoxicity was mainly predicted for coumarins found in beer, sherry, dried parsley, fresh parsley and raw celery stalks. The results obtained can be interesting for the future design of functional foods and dietary supplements. These studies constitute a reference for the genotoxic chemoinformatic analysis of bioactive compounds present in databases of food composition.

  2. Dye-sensitized nanocrystalline TiO{sub 2} solar cells based on novel coumarin dyes

    Energy Technology Data Exchange (ETDEWEB)

    Hara, Kohjiro; Tachibana, Yasuhiro; Sayama, Kazuhiro; Sugihara, Hideki; Arakawa, Hironori [National Inst. of Advanced Industrial Science and Technology, Ibaraki (Japan). Photoreaction Control Research Center; Ohga, Yasuyo; Shinpo, Akira; Suga, Sadaharu [Hayashibara Biochemical Labs., Okayama (Japan)

    2003-04-30

    We have developed dye-sensitized nanocrystalline TiO{sub 2} solar cells (DSSCs) based on novel coumarin-dye photosensitizers. The absorption spectra of these novel dyes are red-shifted remarkably in the visible region relative to the spectrum of C343, a conventional coumarin dye. Introduction of a methine unit (-CH=CH-) connecting the cyano (-CN) and carboxyl (-COOH) groups into the coumarin framework expanded the {pi}-conjugation in the dye and thus resulted in a wide absorption in the visible region. These novel dyes performed as efficient photosensitizers for DSSCs. A DSSC based on 2-cyano-5-(1,1,6,6-tetramethyl-10-oxo-2,3,5,6-tetrahydro-1H,4H,10H-11-oxa-3a-a= za-benzo[de]anthracen-9-yl)-penta-2,4-dienoic acid (NKX-2311), produced a 6.0% solar energy-to-electricity conversion efficiency ({eta}), the highest performance among DSSCs based on organic-dye photosensitizers, under AM 1.5 irradiation (100 mW cm{sup -2}) with a short-circuit current density (J{sub sc}) of 14.0 mA cm{sup -2}, an open-circuit voltage (V{sub oc}) of 0.60 V, and a fill factor of 0.71. Our results suggests that the structure of NKX-2311 whose carboxyl group is directly connected to the -CH=CH- unit, is advantageous for effective electron injection from the dye into the conduction band of TiO{sub 2}. In addition, the cyano group, owing to its strong electron-withdrawing ability, might play an important role in electron injection in addition to a red shift in the absorption region. On a long-term stability test under continuous irradiation with white light (80 mW cm{sup -2}), stable performance was attained with a solar cell based on the NKX-2311 dye with a turnover number of 2.6x10{sup 7} per one molecule. (Author)

  3. Dye-sensitized nanocrystalline TiO{sup 2} solar cells based on novel coumarin dyes

    Energy Technology Data Exchange (ETDEWEB)

    Hara, Kohjiro; Tachibana, Yasuhiro; Sayama, Kazuhiro; Sugihara, Hideki; Arakawa, Hironori [Photoreaction Control Research Center (PCRC) Science and Technology, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565 (Japan); Ohga, Yasuyo; Shinpo, Akira; Suga, Sadaharu [Hayashibara Biochemical Laboratories, Inc., 564-176 Fujita, Okayama 701-0221 (Japan)

    2003-04-30

    We have developed dye-sensitized nanocrystalline TiO{sub 2} solar cells (DSSCs) based on novel coumarin-dye photosensitizers. The absorption spectra of these novel dyes are red-shifted remarkably in the visible region relative to the spectrum of C343, a conventional coumarin dye. Introduction of a methine unit (-CH==CH-) connecting the cyano (-CN) and carboxyl (-COOH) groups into the coumarin framework expanded the {pi}-conjugation in the dye and thus resulted in a wide absorption in the visible region. These novel dyes performed as efficient photosensitizers for DSSCs. A DSSC based on 2-cyano-5-(1,1,6,6-tetramethyl-10-oxo-2,3,5,6-tetrahydro-1H,4H,10H-11-oxa-3a- aza-benzo[de]anthracen-9-yl)-penta-2,4-dienoic acid (NKX-2311), produced a 6.0% solar energy-to-electricity conversion efficiency ({eta}), the highest performance among DSSCs based on organic-dye photosensitizers, under AM 1.5 irradiation (100mWcm{sup -2}) with a short-circuit current density (J{sub sc}) of 14.0mAcm{sup -2}, an open-circuit voltage (V{sub oc}) of 0.60V, and a fill factor of 0.71. Our results suggests that the structure of NKX-2311 whose carboxyl group is directly connected to the -CH==CH- unit, is advantageous for effective electron injection from the dye into the conduction band of TiO{sub 2}. In addition, the cyano group, owing to its strong electron-withdrawing ability, might play an important role in electron injection in addition to a red shift in the absorption region. On a long-term stability test under continuous irradiation with white light (80mWcm{sup -2}), stable performance was attained with a solar cell based on the NKX-2311 dye with a turnover number of 2.6x10{sup 7} per one molecule.

  4. Auxin-like effects of the natural coumarin scopoletin on Arabidopsis cell structure and morphology.

    Science.gov (United States)

    Graña, Elisa; Costas-Gil, Aitana; Longueira, Sabela; Celeiro, María; Teijeira, Marta; Reigosa, Manuel J; Sánchez-Moreiras, Adela M

    2017-11-01

    The mode of action and phytotoxic potential of scopoletin, a natural compound belonging to the group of coumarins, has been evaluated in detail. Analysis conducted by light and electron transmission microscopy showed strong cell and tissue abnormalities on treated roots, such as cell wall malformations, multi-nucleated cells, abnormal nuclei and tissue disorganization. Scopoletin compromised root development by inducing wrong microtubule assembling, mitochondrial membrane depolarization and ultimate cell death, in a way similar to auxin herbicides. The structural similarities of the natural compound scopoletin and the auxin herbicide 2,4-D, as well as the ability of scopoletin to fit into the auxin-binding site TIR1, were analyzed, suggesting that the phytotoxic activity of scopoletin matches with that exhibited by auxinic herbicides. Copyright © 2017 Elsevier GmbH. All rights reserved.

  5. Synthesis and electrochemical and biological studies of novel coumarin-chalcone hybrid compounds.

    Science.gov (United States)

    Pérez-Cruz, Fernanda; Vazquez-Rodriguez, Saleta; Matos, Maria João; Herrera-Morales, Alejandra; Villamena, Frederick A; Das, Amlan; Gopalakrishnan, Bhavani; Olea-Azar, Claudio; Santana, Lourdes; Uriarte, Eugenio

    2013-08-08

    A series of novel hydroxy-coumarin-chalcone hybrid compounds 2a-i has been synthesized by employing a simple and efficient methodology. An electrochemical characterization using cyclic voltammetry and ESR spectroscopy were carried out to characterize the oxidation mechanism for the target compounds. The antioxidant capacity and reactivity were determined by ORAC and ESR assays, respectively. Biological assays were assessed to evaluate the cytotoxicity and cytoprotection capacity against ROS/RNS on BAEC. The results revealed that all tested compounds present ORAC values that are much higher than other well-known antioxidant compounds such as quercetin and catechin. Compound 2e showed the highest ORAC value (14.1) and also presented a low oxidation potential, good scavenging capacity against hydroxyl radicals, low cytotoxicity, and high cytoprotective activity.

  6. Antibacterial activity of crude extracts from Mexican medicinal plants and purified coumarins and xanthones.

    Science.gov (United States)

    Yasunaka, Kakuko; Abe, Fumiko; Nagayama, Ariaki; Okabe, Hikaru; Lozada-Pérez, Lucio; López-Villafranco, Edith; Muñiz, Elizabeth Estrada; Aguilar, Abigail; Reyes-Chilpa, Ricardo

    2005-02-28

    Thirty-two extracts from 22 Mexican medicinal plants of 15 different families were assayed to determine their antibacterial activity against Escherichia coli and Staphylococcus aureus. Seventeen plants showed antibacterial activity, while five plants showed no activity against both bacteria. All of the extracts showed higher activity against Staphylococcus aureus (methicillin-sensitive and methicillin-resistant) than against Escherichia coli, except one. Among the plants examined, Bursera simaruba (L.) Sarg. (Burseraceae), Haematoxylum brasiletto H. Karst. (Fabaceae), Calophyllum brasiliense Cambess. (Clusiaceae), and Mammea americana L. (Clusiaceae) were highly active against Staphylococcus aureus. Coumarins (mammea A/BA and mammea A/AA) and xanthones, namely jacareubin and 1,3,5,6-tetrahydroxy-2-(3,3-dimethylallyl) xanthone, were isolated as the principle compounds from the last two plants.

  7. Attenuating effect of bioactive coumarins from Convolvulus pluricaulis on scopolamine-induced amnesia in mice.

    Science.gov (United States)

    Malik, Jai; Karan, Maninder; Vasisht, Karan

    2016-01-01

    Convolvulus pluricaulis Chois. (Convolvulaceae) has been used in Ayurveda as Medhya Rasyana (nervine tonic) to treat various mental disorders. This study was designed to isolate the bioactive compound(s) of this plant and to evaluate their effect against scopolamine-induced amnesia. Column chromatography of the chloroform and ethyl-acetate fractions led to the isolation of three coumarins identified as scopoletin, ayapanin and scopolin. All the three compounds at 2.5, 5, 10 and 15 mg/kg, p.o. were evaluated for memory-enhancing activity against scopolamine-induced amnesia using elevated plus maze and step down paradigms. Effect on acetylcholinesterase activity in mice brain was also evaluated. Scopoletin and scopolin, in both the paradigms, significantly and dose dependently attenuated the scopolamine-induced amnesic effect. Furthermore, these compounds at 10 and 15 mg/kg exhibited activity comparable to that of standard drug, donepezil. The compounds also exhibited significant acetylcholinesterase inhibitory activity.

  8. Synthesis and antimicrobial studies on novel sulfonamides containing 4-azidomethyl coumarin.

    Science.gov (United States)

    Basanagouda, Mahantesha; Shivashankar, K; Kulkarni, Manohar V; Rasal, Vijaykumar P; Patel, Harishchandra; Mutha, Sumit S; Mohite, Ashwini A

    2010-03-01

    A series of new and novel coumarin-6-sulfonamides with a free C4-azidomethyl group have been synthesized as antimicrobials in three steps starting from 7-methyl-4-bromomethylcoumarin 1. The reaction of 1 with chlorosulfonic acid was found to yield the corresponding 6-sulfonylchloride 2, which when treated with sodium azide led to intermediate 3. The title sulfonamides 5a-y were obtained from the reaction of 3 with various aromatic amines 4 in refluxing benzene. The chemical structures of the compounds were elucidated by IR, NMR and LC-MS spectral data. All the synthesized compounds have been screened for their in vitro anti-bacterial and anti-fungal activities. Some of the compounds have been found to be active against both bacterial species at a concentration of 1 microg/mL. Copyright (c) 2009 Elsevier Masson SAS. All rights reserved.

  9. [Studies on coumarins from fruit of Cnidium monnieri and their cytotoxic activities].

    Science.gov (United States)

    Duan, Xu-hong; Zhang, Yu-zhuo; He, Pei; Ma, Zong-min; Pei, Lin

    2015-09-01

    This study is to study is to investigate the coumarins from Fruit of Cnidium monnieri and their cytotoxic activities. The constituents were separated by column chromatography, and their structures were elucidated by spectroscopic data analyses. The isolated compounds were evaluated for their cytoxic activities by MTT method. Eleven compounds were isolated and identified as osthole (1), bergaptan (2), xanthotoxol (3), xanthotoxin (4), imperatorin (5), isopimpinellin (6), osthenol (7), psoralen (8), 5,7-dimethoxycoumarin (9), oxypeucedaninhydrate (10), and swietenocoumarin F (11). Compounds 7, 9-11 were isolated from the Cnidium genus for the first time. Compounds 1,5,10 and 11 showed significant cytotoxic activities against L1210 cell lines at a concentration of 1 x 10(-5) mol x L(-1) with inhibitory rates of were 70.13, 63.10, 55.77, and 75.08% respectively.

  10. Isolationand structure elucidation of coumarin and cinamate derivatives from Lycium ruthenicum

    Directory of Open Access Journals (Sweden)

    Hassan Valizadeh

    2014-10-01

    Full Text Available Lyciumspecies is a popular medicinal plant in the traditional Chinese medicine and Lycium ru-thenicum is a native medicinal plant of Iran. Lycium genus has several biologically important properties too. Investigation of chemical composition of ethyl acetate extract of this plant is the goal of this study. Two coumarins (Scopoletin and Sculetin and Methyl-2-hydroxy-4-undecanoxy-trans-cinamate were isolated and characterized as the major constituents using 1H NMR, 13C NMR and FT-IR spectroscopic data, MS spectrometry, elemental analysis and by comparison with the literature values. Phytochemical investigation of Lyciumruthenicum demonstrated the presence of important biologically active compounds. This is the first phyto-chemical study of this species in Iran.

  11. Three-Component Coupling Reactions of Arynes for the Synthesis of Benzofurans and Coumarins

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    Eito Yoshioka

    2014-01-01

    Full Text Available The domino three-component coupling reaction of arynes with DMF and active methylenes or methines was studied as a highly efficient method for preparing heterocycles. Coumarin derivative 5 was formed when diethyl malonate (2 or α-bromomalonate (3 were used as a C2-unit. In contrast, dihydrobenzofurans 7a and 7b were obtained by using α-chloroenolates generated from α-chloromalonates 4a and 4b and Et2Zn. The benzofuran 15a could be obtained by using ethyl iodoacetate (14 as a C1-unit. The one-pot conversion of dihydrobenzofurans 7a, 7b and 8a into benzofurans 15a and 15b was also studied. The direct synthesis of benzofuran 15b was achieved by using the active methine 18 having ketone and ester groups.

  12. Electrochemiluminescence Study of Europium (III Complex with Coumarin3-Carboxylic Acid

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    Stefan Lis

    2008-01-01

    Full Text Available The europium (III complex of coumarin-3-carboxylic acid (C3CA has been prepared and characterized on the basis of elemental analysis, IR, and emission (photoluminescence and electrochemiluminescence spectroscopy. The synthesised complex having a formula Eu(C3CA2(NO3(H2O2 was photophysically characterized in solution and in the solid state. Electrochemiluminescence, ECL, of the system containing the Eu(III/C3CA complex was studied using an oxide-covered aluminium electrode. The goal of these studies was to show the possibility of the use of electrochemical excitation of the Eu(III ion in aqueous solution for emission generation. The generated ECL emission was very weak, and therefore its measurements and spectral analysis were carried out with the use of cut-off filters method. The studies proved a predominate role of the ligand-to-metal energy transfer (LMET in the generated ECL.

  13. The coumarin herniarin as a sensitizer in German chamomile [Chamomilla recutita (L.) Rauschert, Compositae].

    Science.gov (United States)

    Paulsen, Evy; Otkjaer, Aksel; Andersen, Klaus E

    2010-06-01

    Although German chamomile (Chamomilla recutita) is considered a weak sensitizer, recent studies have shown several possible non-sesquiterpene lactone allergens in tea (infusions) from the plant. The aim of this study was to report the results of patch testing with herniarin (7-methoxycoumarin), which is one of the possible coumarin allergens in chamomile. Between 1991 and 2009, selected patients with known or suspected Compositae contact allergy were patch tested with herniarin 1% petrolatum. Among 36 patients tested, there was one positive and three doubtful positive reactions to herniarin. All 4 patients had a relevant contact allergy to German chamomile, whereas the majority of the remaining 32 patients had chamomile allergy of unknown relevance. The clinical results suggest that herniarin indeed is one of the non-sesquiterpene lactone sensitizers in German chamomile and that sensitization may occur through, for example, external use of chamomile tea or use of chamomile-containing topical herbal remedies.

  14. Chlorinated coumarins from the polypore mushroom Fomitopsis officinalis and their activity against Mycobacterium tuberculosis.

    Science.gov (United States)

    Hwang, Chang Hwa; Jaki, Birgit U; Klein, Larry L; Lankin, David C; McAlpine, James B; Napolitano, José G; Fryling, Nicole A; Franzblau, Scott G; Cho, Sang Hyun; Stamets, Paul E; Wang, Yuehong; Pauli, Guido F

    2013-10-25

    An EtOH extract of the polypore mushroom Fomitopsis officinalis afforded two new naturally occurring chlorinated coumarins, which were identified as the previously synthesized compounds 6-chloro-4-phenyl-2H-chromen-2-one (1) and ethyl 6-chloro-2-oxo-4-phenyl-2H-chromen-3-carboxylate (2). The structures of the two isolates were deduced by ab initio spectroscopic methods and confirmed by chemical synthesis. In addition, an analogue of each was synthesized as 7-chloro-4-phenyl-2H-chromen-2-one (3) and ethyl 7-chloro-2-oxo-4-phenyl-2H-chromen-3-carboxylate (4). All four compounds were characterized physicochemically, and their antimicrobial activity profiles revealed a narrow spectrum of activity with lowest MICs against the Mycobacterium tuberculosis complex.

  15. Isolation, characterisation and antibacterial activity studies of coumarins from Rhododendron lepidotum Wall. ex G. Don, Ericaceae

    Directory of Open Access Journals (Sweden)

    Shakeel-U-Rehman

    2010-11-01

    Full Text Available Six coumarins daphnin (1, daphnetin (2, daphnetin glucoside (3, rhodonetin (4, rhodonin (5 and umbelliferone (6 were isolated from the methanolic extract of Rhododendron lepidotum Wall. ex G. Don, Ericaceae (aerial part. The compounds and their acetyl derivatives were screened for antibacterial activity against Staphylococcus aureus ATCC-29213, methicillin resistant Staphylococcus aureus ATCC-15187, Escherichia coli ATCC-8739, Pseudomonas aeruginosa ATCC-9027 by microdilution method as compared to the reference ciprofloxacin. Compound 2 displayed the best antibacterial activity with MIC 125 μg/mL against S. aureus ATCC-29213 and MRSA ATCC-15187 followed by 4 which exhibited the MIC value of 250 μg/mL against all the four tested strains. All molecules showed better antibacterial activity than their acyl derivatives.

  16. Efficient Isolation of Dihydropyranocoumarins and Simple Coumarins from Mutellina purpurea Fruits.

    Science.gov (United States)

    Skalicka-Woźniak, Krystyna; Mroczek, Tomasz; Walasek, Magdalena; Głowniak, Kazimierz

    2016-07-01

    For the first time, the separation of coumarin derivatives from the petroleum ether extract of the fruits of Mutellina purpurea through high-performance countercurrent chromatography (HPCCC) is described. Four compounds, pteryxin (1; 2.72 mg), hyuganin C (2; 7.94 mg), osthol (3; 4.30 mg), and hyuganin A (4; 3.09 mg), were obtained in a single run following the injection of crude extract (300 mg). Additionally, auraptenol (5) and hyuganin D (6) were identified using LC-ESI-(Q)TOF-MS. The structures of the isolated compounds were elucidated through spectroscopic (NMR and MS) methods. This is apparently the first report of the identification of dihydropyranocoumarins in this plant, and the first time that HPCCC was used to separate them. Georg Thieme Verlag KG Stuttgart · New York.

  17. Polar solvation dynamics of coumarin 153 by ultrafast time-resolved fluorescence

    Science.gov (United States)

    Eom, Intae; Joo, Taiha

    2009-12-01

    Polar solvation dynamics of coumarin 153 in acetonitrile, methanol, and butanol are investigated by dynamic Stokes shift function, S(t ). In small protic solvents, it is known that an initial ultrafast component below 50 fs constitutes more than half of the total solvation process. We use fluorescence up-conversion technique via two-photon absorption process, which can provide 40 fs time resolution for the whole emission wavelength range. Moreover, time-resolved fluorescence spectra are recorded directly without the spectral reconstruction. We observe a temporal oscillation in frequency of whole emission spectrum in the solvation curve. In the obtained S(t ), initial solvation time scale is 120 fs, invariant to solvents used in this experiment, although its amplitude varies in different solvents.

  18. Synthesis and biological evaluation of coumarin based isoxazoles, pyrimidinthiones and pyrimidin-2-ones

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    Divyesh Patel

    2017-05-01

    Full Text Available The titled compounds (6′a–k, (7′a–k and (8′a–k were synthesized from chalcones (5a–k having coumarin moiety. Cyclization of chalcones (5a–k with hydroxyl amine hydrochloride, thiourea and urea resulted in corresponding isoxazoles (6′a–k, pyrimidinthiones (7′a–k and pyrimidin-2-ones (8′a–k. Structures of newly synthesized compounds were established on the basis of their elemental analysis, IR, 1H NMR, 13C NMR, and mass spectral data. The synthesized analogs were evaluated for their antimycobacterial activity and antimicrobial activity against eight bacteria (Staphylococcus aureus, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella typhi, Proteus vulgaris, and Shigella flexneri and four fungi (Aspergillus niger, Candida albicans, Aspergillus fumigatus, and Aspergillus clavatus.

  19. Adaptive quantum control of two photon fluorescence on Coumarin 30 by using evolutionary algorithm

    Science.gov (United States)

    Poudel, Milan; Kolomenski, Alexender; Schuessler, Hans

    2006-10-01

    Two-photon excitation fluorescence of complex molecules (Coumarin-30) is successfully optimized by using feedback control pulse shaping technique. For such an optimization we have implemented an evolutionary algorithm [1], [2] in a Lab-view programming environment with a liquid crystal pulse shaper in a folded 4f set up. In the algorithm, one generation uses 48 individuals (vectors of voltage on the LC matrix).For each generation the fitness value is measured for every setting of the mask. A new generation is built from the previous by combining parents (the fittest individuals) and producing the desired degree of mutations (changes of the vector elements by some random value) to provide reasonable convergence. By successive repetition of this scheme, individuals corresponding to the highest fitness values will survive and produce offspring's for subsequent generations. Typically, convergence to the optimum value was achieved after 30 generations. Without any prior knowledge of the molecular system, the optimization goal was automatically achieved by changing the spectral phases [3]. The pulses before and after optimization were measured with GRENOUILLE, a type of second harmonic frequency resolved optical gating (SH FROG). To find the efficient pulse with lower intensity, three types of optimization were performed, the two photon fluorescence signal, the second harmonic signal and the ratio between them. The Intensity of two photon fluorescence of coumarin-30 could be increased noticeably compared to the transform limited pulse optimizing the second harmonic generation. The experimental results appear to be the potential applications of coherent control to the complicated molecular system as well as in bio medical imaging.

  20. Advanced glycation inhibition and protection against endothelial dysfunction induced by coumarins and procyanidins from Mammea neurophylla.

    Science.gov (United States)

    Dang, Bach Tai; Gény, Charlotte; Blanchard, Patricia; Rouger, Caroline; Tonnerre, Pierre; Charreau, Béatrice; Rakolomalala, Gilbertine; Randriamboavonjy, Joseph Iharinjaka; Loirand, Gervaise; Pacaud, Pierre; Litaudon, Marc; Richomme, Pascal; Séraphin, Denis; Derbré, Séverine

    2014-07-01

    Advanced glycation end-products (AGEs) are associated with many pathogenic disorders such as pathogenesis of diabetes or endothelial dysfunction leading to cardiovascular events. Therefore, the identification of new anti-AGE molecules or extracts aims at preventing such pathologies. Many Clusiaceae and Calophyllaceae species are used in traditional medicines to treat arterial hypertension as well as diabetes. Focusing on these plant families, an anti-AGE plant screening allowed us to select Mammea neurophylla for further phytochemical and biological studies. Indeed, both DCM and MeOH stem bark extracts demonstrated in vitro their ability to prevent inflammation in endothelial cells and to reduce vasoconstriction. A bioguided fractionation of these extracts allowed us to point out 4-phenyl- and 4-(1-acetoxypropyl)coumarins and procyanidins as potent inhibitors of AGE formation, potentially preventing endothelial dysfunction. The fractionation steps also led to the isolation of two new compounds, namely neurophyllols A and B from the DCM bark extract together with thirteen known mammea A and E coumarins (mammea A/AA, mammea A/AB, mammea A/BA, mammea A/BB, mammea A/AA cycloD, mammea A/AB cycloD, disparinol B, mammea A/AB cycloE, ochrocarpin A, mammea A/AA cycloF, mammea A/AB cycloF, mammea E/BA, mammea E/BB) as well as δ-tocotrienol, xanthones (1-hydroxy-7-methoxyxanthone, 2-hydroxyxanthone) and triterpenes (friedelin and betulinic acid). During this study, R,S-asperphenamate, previously described from fungal origin was also purified. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Solution-phase synthesis of a combinatorial library of 3-[4-(coumarin-3-yl)-1,3-thiazol-2-ylcarbamoyl]propanoic acid amides.

    Science.gov (United States)

    Zhuravel, Irina O; Kovalenko, Sergiy M; Vlasov, Sergiy V; Chernykh, Valentin P

    2005-02-28

    The parallel solution-phase synthesis of a new combinatorial library of 3-[4-(R1-coumarin-3-yl)-1,3-thiazol-2-ylcarbamoyl]propanoic acid amides 9 has been developed. The synthesis involves two steps: 1) the synthesis of core building blocks - 3- [4-(coumarin-3-yl)-1,3-thiazol-2-ylcarbamoyl]propanoic acids, 6 - by the reaction of 3-(omega-bromacetyl)coumarins 1 with 3-amino(thioxo)methylcarbamoylpropanoic acid (5); 2) the synthesis of the corresponding 3-[4-(coumarin-3-yl)-1,3-thiazol-2-yl- carbamoyl]propanoic acids amides 9 using 1,1'-carbonyldimidazole as a coupling reagent. The advantages of the method compared to existing ones are discussed.

  2. Synergistic of a coumarin derivative with potassium iodide on the corrosion inhibition of aluminum alloy in 1.0 M H2SO4

    Science.gov (United States)

    Mohamad, Abu Bakar; Kadhum, Abdul Amir H.; Al-Amiery, Ahmed A.; Ying, Lim Chai; Musa, Ahmed Y.

    2014-05-01

    Synergistic effects of the addition of KI on the corrosion inhibitive performance of a coumarin derivative on an aluminum alloy in 1.0 M H2SO4 at different temperatures were studied using various electrochemical measurements. Density functional theory was used to calculate the quantum chemical parameters of the coumarin derivative. The experimental results showed that the coumarin derivative is considered as a mixedtype inhibitor. The corrosion potential values were almost unchanged upon the addition of PBBC to the acidic solution. The inhibition efficiency increases with increasing inhibitor concentration and increases further in the presence of 6.02 mM KI but decreases significantly at higher temperature. The adsorption of PBBC obeyed the Langmuir isotherm, and being chemically adsorbed at lower temperatures, while physical adsorption is favoured at higher temperature. The theoretical results indicated that the coumarin derivative was adsorbed onto the surface of Al2024 through the sulfur, oxygen and nitrogen atoms.

  3. A Method for LC-MS/MS Profiling of Coumarins in Zanthoxylum zanthoxyloides (Lam. B. Zepernich and Timler Extracts and Essential Oils

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    Yoro Tine

    2017-01-01

    Full Text Available The metabolites from the coumarin class, present in tissues of plants belonging mainly to the Rutaceae and Apiaceae families, included compounds with high chemical diversity such as simple coumarins and furocoumarins. These health-promoting components are recognized for their valuable biological activities in herbal preparations but also for their phototoxic effects. In this work, a targeted liquid chromatography (LC coupled with tandem mass spectrometry (MS2 was developed for the screening of 39 reference standards of coumarins and furocoumarins in essential oils and plant extracts. Chromatographic separation was accomplished on reversed phase column using water/acetonitrile as the mobile phase and detection was performed on a hybrid QqQ/linear ion trap spectrometer fitted with an atmospheric pressure chemical ionization (APCI source operating in positive ion mode. This analytical approach was applied to investigate the coumarin compositions of fruit essential oils and methanolic extracts obtained from separated parts (fruit, leaf, stem, trunk, and root of Zanthoxylum zanthoxyloides. Ten coumarins and six furanocoumarins were reported in this species and data analyses were used to assess the suitability of these compounds to the metabolomics-based differentiation of plant organs. The quantification criteria of the metabolites in extract samples included linearity, limit of quantification, limit of detection, and matrix effect were validated. As reported for other species of the Rutaceae family, the concentration of coumarins was drastically higher in Z. zanthoxyloides fruits than in other plant organs.

  4. A practical strategy for the characterization of coumarins in Radix Glehniae by liquid chromatography coupled with triple quadrupole-linear ion trap mass spectrometry.

    Science.gov (United States)

    Yang, Wei; Ye, Min; Liu, Man; Kong, Dezhi; Shi, Rui; Shi, Xiaowei; Zhang, Kerong; Wang, Qiao; Lantong, Zhang

    2010-07-02

    The aim of the present study was to develop a practical method for the characterization of coumarins in Radix Glehniae by liquid chromatography-mass spectrometry (LC-MS). First, 10 coumarin standards (including two pairs of isomers) were studied, and mass spectrometry fragmentation patterns and elution time rules for the coumarins were found. Then, an extract of Radix Glehniae was analyzed by the combination of two scan modes, i.e., multiple ion monitoring-information-dependent acquisition-enhanced product ion mode (MIM-IDA-EPI) and precursor scan information-dependent acquisition-enhanced product ion mode (PREC-IDA-EPI) on a hybrid triple quadrupole-linear ion trap mass spectrometer. A total of 41 coumarins were identified on the basis of their mass spectrometry fragmentation patterns. This is the first time that these two scan modes have been combined to characterize chemical constituents in traditional Chinese medicine. This new method allowed the identification of coumarins in Radix Glehniae in trace amounts. The methodology proposed in this study could be valuable for the structural characterization of coumarins from complex natural and synthetic sources. Copyright 2010 Elsevier B.V. All rights reserved.

  5. A Method for LC-MS/MS Profiling of Coumarins in Zanthoxylum zanthoxyloides (Lam.) B. Zepernich and Timler Extracts and Essential Oils.

    Science.gov (United States)

    Tine, Yoro; Renucci, Franck; Costa, Jean; Wélé, Alassane; Paolini, Julien

    2017-01-22

    The metabolites from the coumarin class, present in tissues of plants belonging mainly to the Rutaceae and Apiaceae families, included compounds with high chemical diversity such as simple coumarins and furocoumarins. These health-promoting components are recognized for their valuable biological activities in herbal preparations but also for their phototoxic effects. In this work, a targeted liquid chromatography (LC) coupled with tandem mass spectrometry (MS²) was developed for the screening of 39 reference standards of coumarins and furocoumarins in essential oils and plant extracts. Chromatographic separation was accomplished on reversed phase column using water/acetonitrile as the mobile phase and detection was performed on a hybrid QqQ/linear ion trap spectrometer fitted with an atmospheric pressure chemical ionization (APCI) source operating in positive ion mode. This analytical approach was applied to investigate the coumarin compositions of fruit essential oils and methanolic extracts obtained from separated parts (fruit, leaf, stem, trunk, and root) of Zanthoxylum zanthoxyloides . Ten coumarins and six furanocoumarins were reported in this species and data analyses were used to assess the suitability of these compounds to the metabolomics-based differentiation of plant organs. The quantification criteria of the metabolites in extract samples included linearity, limit of quantification, limit of detection, and matrix effect were validated. As reported for other species of the Rutaceae family, the concentration of coumarins was drastically higher in Z. zanthoxyloides fruits than in other plant organs.

  6. Synergism of coumarins from the Chinese drug Zanthoxylum nitidum with antibacterial agents against methicillin-resistant Staphylococcus aureus (MRSA).

    Science.gov (United States)

    Zuo, Guo-Ying; Wang, Chun-Juan; Han, Jun; Li, Yu-Qing; Wang, Gen-Chun

    2016-12-15

    Methicillin-resistant Staphylococcus aureus (MRSA) poses a serious therapeutic challenge in current clinic and new drug development. Natural coumarins have diverse bioactivities and the potential of resistance modifying effects. This study is to present in-depth evaluations of in vitro antimicrobial activities of four natural coumarins 5-geranyloxy-7-methoxycoumarin (Gm, 1), (5,7-dimethoxy-8-prenyloxycoumarin (artanin, Ar, 2)), isopimpinellin (Is, 3) and phellopterin (Ph, 4) from Zanthoxylum nitidum (Roxb.) DC. (Rutaceae) extracts, focusing on their potential restoration the activity of conventional antibacterial agents against clinical MRSA strains. Bioactivity-guided fractionation and spectral analyses were used to isolate the coumarins and identify the structures, respectively. The double broth microdilution method was used to assay the coumarins' alone activity. The classic checkerboard microdilution and dynamic time-killing methods were used to evaluate combinatory effects. The four plant coumarins Gm (1), Ar (2), Is (3) and Ph (4) were isolated and identified from Z. nitidum extracts. Coumarins 1-4 displayed promising inhibition against both MSSA and MRSA with minimal inhibitory concentrations (MICs) of 8-64µg/ml, but very weak against Gram-negative pathogen and yeast with MICs of 256 to ≥1024µg/ml. The geranyloxy and prenyloxy substitutions showed to be more active than the methoxy substitution on the coumarin skeletons. 1-4 also showing different extent of synergism with a total of eight conventional antibacterial agents, i.e. chloramphenicol (CL), gentamicin (CN), fosfomycin (FF), levofloxacin (LE), minocycline (MI), piperacillin/tazobactam (P/T), teicoplanin (TE) and vancomycin (VA) against ten clinical MRSA strains. Four to ten of the tested MRSA strains showed bacteriostatic synergy in the eleven combinations. The anti-MRSA modifying effects were related to different arrangement in the combinations with fractional inhibitory concentration indices

  7. Determination of coumarin, vanillin, and ethyl vanillin in vanilla extract products: liquid chromatography mass spectrometry method development and validation studies.

    Science.gov (United States)

    de Jager, Lowri S; Perfetti, Gracia A; Diachenko, Gregory W

    2007-03-23

    A LC-MS method was developed for the determination of coumarin, vanillin, and ethyl vanillin in vanilla products. Samples were analyzed using LC-electrospray ionization (ESI)-MS in the positive ionization mode. Limits of detection for the method ranged from 0.051 to 0.073 microg mL(-1). Using the optimized method, 24 vanilla products were analyzed. All samples tested negative for coumarin. Concentrations ranged from 0.38 to 8.59 mg mL(-1) (x =3.73) for vanillin and 0.33 to 2.27 mg mL(-1) (x =1.03) for ethyl vanillin. The measured concentrations are compared to values calculated using UV monitoring and to results reported in a similar survey in 1988. Analytical results, method precision, and accuracy data are presented.

  8. Potential antiproliferative effect of isoxazolo- and thiazolo coumarin derivatives on breast cancer mediated bone and lung metastases

    Directory of Open Access Journals (Sweden)

    Ballazhi Lulzime

    2015-03-01

    Full Text Available The study highlights the current progress in the development of coumarin scaffolds for drug discovery as novel anticancer agents in metastatic breast cancer. Eight compounds, combining the coumarin core and five membered heterocycles (isoxazoles and thiazoles in hydrazinyldiene- -chroman-2,4-diones, were characterized in terms of a potential antiproliferative effect on bone (SCP1833 and lung (SCP4175 metastatic breast cancer cell lines using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay. Cell viability was evaluated after 48 and 72 h of treatment and the 50 % inhibitory concentrations were determined. The results demonstrated dose- and time-dependent activity, with the most potent molecules having a thiazole moiety, without or with additional methyl group(s attached to the carbon(s at position(s 5 and/or 4 in the thiazole ring. These molecules possessed significantly higher potency against both test cell lines compared to 4-hydroxycoumarin

  9. Coumarins from the Herb Cnidium monnieri and chemically modified derivatives as antifoulants against Balanus albicostatus and Bugula neritina larvae.

    Science.gov (United States)

    Wang, Zhan-Chang; Feng, Dan-Qing; Ke, Cai-Huan

    2013-01-09

    In the search for new environmental friendly antifouling (AF) agents, four coumarins were isolated from the herbal plant Cnidium monnieri, known as osthole (1), imperatorin (2), isopimpinellin (3) and auraptenol (4). Furthermore, five coumarin derivatives, namely 8-epoxypentylcoumarin (5), meranzin hydrate (6), 2'-deoxymetranzin hydrate (7), 8-methylbutenalcoumarin (8), and micromarin-F (9) were synthesized from osthole. Compounds 1, 2, 4, 7 showed high inhibitory activities against larval settlement of Balanus albicostatus with EC(50) values of 4.64, 3.39, 3.38, 4.67 μg mL-1. Compound 8 could significantly inhibit larval settlement of Bugula neritina with an EC(50) value of 3.87 μg mL-1. The impact of functional groups on anti-larval settlement activities suggested that the groups on C-5' and C-2'/C-3' of isoamylene chian could affect the AF activities.

  10. Coumarins from the Herb Cnidium monnieri and Chemically Modified Derivatives as Antifoulants against Balanus albicostatus and Bugula neritina Larvae

    Directory of Open Access Journals (Sweden)

    Zhan-Chang Wang

    2013-01-01

    Full Text Available In the search for new environmental friendly antifouling (AF agents, four coumarins were isolated from the herbal plant Cnidium monnieri, known as osthole (1, imperatorin (2, isopimpinellin (3 and auraptenol (4. Furthermore, five coumarin derivatives, namely 8-epoxypentylcoumarin (5, meranzin hydrate (6, 2'-deoxymetranzin hydrate (7, 8-methylbutenalcoumarin (8, and micromarin-F (9 were synthesized from osthole. Compounds 1, 2, 4, 7 showed high inhibitory activities against larval settlement of Balanus albicostatus with EC50 values of 4.64, 3.39, 3.38, 4.67 μg mL−1. Compound 8 could significantly inhibit larval settlement of Bugula neritina with an EC50 value of 3.87 μg mL−1. The impact of functional groups on anti-larval settlement activities suggested that the groups on C-5' and C-2'/C-3' of isoamylene chian could affect the AF activities.

  11. Coumarins from the Herb Cnidium monnieri and Chemically Modified Derivatives as Antifoulants against Balanus albicostatus and Bugula neritina Larvae

    Science.gov (United States)

    Wang, Zhan-Chang; Feng, Dan-Qing; Ke, Cai-Huan

    2013-01-01

    In the search for new environmental friendly antifouling (AF) agents, four coumarins were isolated from the herbal plant Cnidium monnieri, known as osthole (1), imperatorin (2), isopimpinellin (3) and auraptenol (4). Furthermore, five coumarin derivatives, namely 8-epoxypentylcoumarin (5), meranzin hydrate (6), 2′-deoxymetranzin hydrate (7), 8-methylbutenalcoumarin (8), and micromarin-F (9) were synthesized from osthole. Compounds 1, 2, 4, 7 showed high inhibitory activities against larval settlement of Balanus albicostatus with EC50 values of 4.64, 3.39, 3.38, 4.67 μg mL−1. Compound 8 could significantly inhibit larval settlement of Bugula neritina with an EC50 value of 3.87 μg mL−1. The impact of functional groups on anti-larval settlement activities suggested that the groups on C-5′ and C-2′/C-3′ of isoamylene chian could affect the AF activities. PMID:23303279

  12. Coumarin-based fluorescence hybrid silica material used for selective detection and absorption of Hg2+ in aqueous media

    Science.gov (United States)

    Meng, Qingtao; Jia, Hongmin; Wang, Cuiping; Zhao, Hongbin; Lu, Gonghao; Hu, Zhizhi; Zhang, Zhiqiang; Duan, Chunying

    2014-11-01

    An inorganic-organic hybrid fluorescence material (C-SBA-15) was prepared by covalent immobilization of a coumarin derivative within the channels of SBA-15. The characterization results of XRD, TEM micrographs, FT-IR and UV-vis demonstrate that coumarin is successfully grafted onto the inner surface of SBA-15 and its organized structure is preserved. C-SBA-15 can detect Hg2+ with high selectivity to Pb2+, Zn2+, Cu2+, Mn2+, Cd2+, Co2+, Ag+, Fe3+, Ni2+, K+, Na+, Ca2+, Mg2+ and Li+ in water. Furthermore, the fluorogenical response is reversible by treating with EDTA and do not vary over a broad pH range (5.0-10.5). C-SBA-15 features more outstanding absorbing capacity for Hg2+ among other HTM ions in water.

  13. Coumarins from Angelica decursiva inhibit lipopolysaccharide-induced nitrite oxide production in RAW 264.7 cells.

    Science.gov (United States)

    Ishita, Ishrat Jahan; Nurul Islam, Md; Kim, Yeong Shik; Choi, Ran Joo; Sohn, Hee Sook; Jung, Hyun Ah; Choi, Jae Sue

    2016-01-01

    Angelica decursiva has long been used in Korean traditional medicine as an antitussive, analgesic, antipyretic, and cough remedy. In this study, the anti-inflammatory activity of 9 coumarin derivatives isolated from a 90 % methanol fraction was evaluated via inhibition of production of nitric oxide (NO) and tumor necrosis factor-α (TNF-α), as well as the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Among the tested compounds, edulisin II (1) exhibited the most potent NO production inhibitory activity, followed by decursidin (2), Pd-C-III (3), 4-hydroxy Pd-C-III (4), Pd-C-I (5), and Pd-C-II (6). In contrast, (+)-trans-decursidinol (7) did not exhibit NO suppressive effects on LPS-stimulated RAW 264.7 cells. Structure-activity relationships revealed that esterification of the hydroxyl at C-3' or C-4' of 7 with an angeloyl/senecioyl/acetyl group is essential for its inhibitory activity against NO production, while the number of angeloyl or senecioyl groups, and their positions greatly affect the potency of these coumarins. Coumarins 1-6 also inhibited TNF-α production and iNOS protein expression, while compounds 1-4 inhibited COX-2 protein expression in LPS-stimulated RAW 264.7 cells. These results suggest that coumarins isolated from A. decursiva might be used as potential leads for the development of therapeutic agents for inflammation-associated disorders.

  14. Novel coumarin glycoside and phenethyl vanillate from Notopterygium forbesii and their binding affinities for opioid and dopamine receptors

    Science.gov (United States)

    Ma, Zhongze; Xu, Wei; Liu-Chen, Lee-Yuan; Lee, David Y. W.

    2008-01-01

    Bioactivity-guided fractionation of Notopterygium forbesii has resulted in the isolation of one new coumarin glycoside and one new phenethyl vanillate, together with seventeen known compounds. The structures of these compounds were characterized by spectroscopic methods. These compounds were evaluated for their binding affinities to the opioid and dopamine receptors, and falcarindiol showed weak binding affinities to opioid receptors and moderate affinity for D1 receptor (Ki = 192±6 nM). PMID:18166466

  15. Different susceptibilities of Leishmania spp. promastigotes to the Annona muricata acetogenins annonacinone and corossolone, and the Platymiscium floribundum coumarin scoparone.

    Science.gov (United States)

    Vila-Nova, Nadja Soares; de Morais, Selene Maia; Falcão, Maria José Cajazeiras; Alcantara, Terezinha Thaize Negreiros; Ferreira, Pablito Augusto Travassos; Cavalcanti, Eveline Solon Barreira; Vieira, Icaro Gusmão Pinto; Campello, Cláudio Cabral; Wilson, Mary

    2013-03-01

    Leishmaniasis is a zoonotic disease that can manifest itself in visceral and cutaneous form. The aim of this study was to search for new leishmanicidal compounds. Preliminarily, Artemia salina assay was applied to compounds from two plants found in Northeastern Brazil, Platymiscium floribundum and Annona muricata. Then these compounds were tested against three Leishmania species (Leishmania donovani, Leishmania mexicana and Leishmania major). A screening assay using luciferase-expressing promastigote form were used to measure the viability of promastigote One coumarin, scoparone, isolated from P. floribundum and two acetogenins, annonacinone and corossolone isolated from A. muricata showed leishmanicidal activity in all species tested. Nevertheless, Leishmania species indicated different susceptibilities in relation to the tested compounds: L. mexicana was more sensitive to scoparone followed by L. major and L. donovani. The three species presented similar inhibition to corossolone and annonacinone. Acetogenin annonacinone (EC(50)=6.72-8.00 μg/mL) indicated high leishmanicidal activity; corossolone (EC(50)=16.14-18.73 μg/mL) and scoparone (EC(50)=9.11-27.51 μg/mL) moderate activity. A. saline larvae were less sensitive to the coumarin scoparone and acetogenin corossolone was the most toxic. In conclusion, the leishmanicidal activity demonstrated by the coumarin and acetogenins indicate these compounds for further studies aiming the development of new leishmanicidal agents. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. Preparative isolation and purification of coumarins from Peucedanum praeruptorum Dunn by high-speed counter-current chromatography.

    Science.gov (United States)

    Liu, Renmin; Feng, Lei; Sun, Ailing; Kong, Lingyi

    2004-11-19

    A preparative high-speed counter-current chromatography (HSCCC) method for isolation and purification of coumarins from Peucedanum praeruptorum Dunn (Baihuaqianhu in Chinese) was successfully established by using light petroleum-ethyl acetate-methanol-water as the two-phase solvent system in gradient elution mode. The upper phase of light petroleum-ethyl acetate-methanol-water (5:5:5:5, v/v) was used as the stationary phase of HSCCC. The mobile phase used in HSCCC was the lower phase of light petroleum-ethyl acetate-methanol-water (5:5:5:5, v/v) and light petroleum-ethyl acetate-methanol-water (5:5:6.5:3.5, v/v) that was changed in gradient. Four kinds of coumarins and another unknown compound were obtained and yielded 5.3 mg of qianhucoumarin D, 7.7 mg of Pd-Ib, 35.8 mg of (+)-praeruptorin A, 31.9 mg of (+)-praeruptorin B and 6.4 mg of unknown compound with the purity of 98.6%, 92.8%, 99.5%, 99.4% and 99.8% in one-step separation, respectively. The structures of the coumarins were identified by 1H NMR and 13C NMR.

  17. Aromatase Inhibitory Activity of Geranylated Coumarins, Mammeasins C and D, Isolated from the Flowers of Mammea siamensis.

    Science.gov (United States)

    Ninomiya, Kiyofumi; Shibatani, Kanae; Sueyoshi, Mayumi; Chaipech, Saowanee; Pongpiriyadacha, Yutana; Hayakawa, Takao; Muraoka, Osamu; Morikawa, Toshio

    2016-01-01

    A methanol extract of the flowers of Mammea siamensis (Calophyllaceae) was found to inhibit enzymatic activity against aromatase (IC50=16.5 µg/mL). From the extract, two new geranylated coumarins, mammeasins C (1) and D (2), were isolated together with seven coumarins: 8-hydroxy-5-methyl-7-(3,7-dimethyl-octa-2,6-dienyl)-9-(2-methyl-1-oxobutyl)-4,5-dihydropyrano[4,3,2-de]chromen-2-one (9), 8-hydroxy-5-methyl-7-(3,7-dimethyl-octa-2,6-dienyl)-9-(3-methyl-1-oxobutyl)-4,5-dihydropyrano[4,3,2-de]chromen-2-one (10), mammeas A/AA (14), A/AB (15), A/AA cyclo D (18), E/BA (23), and E/BC cyclo D (25). The structures of 1 and 2 were elucidated on the basis of spectroscopic evidence. Among the isolates including 17 previously reported coumarins, 1 (IC50=2.7 µM), 2 (3.6 µM), and mammea B/AB cyclo D (21, 3.1 µM) showed relatively strong inhibitory activities comparable to the activity of the synthetic nonsteroidal aromatase inhibitor aminoglutethimide (2.0 µM).

  18. Biodiesel production by enzyme-catalyzed transesterification

    Directory of Open Access Journals (Sweden)

    Stamenković Olivera S.

    2005-01-01

    Full Text Available The principles and kinetics of biodiesel production from vegetable oils using lipase-catalyzed transesterification are reviewed. The most important operating factors affecting the reaction and the yield of alkyl esters, such as: the type and form of lipase, the type of alcohol, the presence of organic solvents, the content of water in the oil, temperature and the presence of glycerol are discussed. In order to estimate the prospects of lipase-catalyzed transesterification for industrial application, the factors which influence the kinetics of chemically-catalysed transesterification are also considered. The advantages of lipase-catalyzed transesterification compared to the chemically-catalysed reaction, are pointed out. The cost of down-processing and ecological problems are significantly reduced by applying lipases. It was also emphasized that lipase-catalysed transesterification should be greatly improved in order to make it commercially applicable. The further optimization of lipase-catalyzed transesterification should include studies on the development of new reactor systems with immobilized biocatalysts and the addition of alcohol in several portions, and the use of extra cellular lipases tolerant to organic solvents, intracellular lipases (i.e. whole microbial cells and genetically-modified microorganisms ("intelligent" yeasts.

  19. Zeolite 5A Catalyzed Etherification of Diphenylmethanol

    Science.gov (United States)

    Cooke, Jason; Henderson, Eric J.; Lightbody, Owen C.

    2009-01-01

    An experiment for the synthetic undergraduate laboratory is described in which zeolite 5A catalyzes the room temperature dehydration of diphenylmethanol, (C[subscript 6]H[subscript 5])[subscript 2]CHOH, producing 1,1,1',1'-tetraphenyldimethyl ether, (C[subscript 6]H[subscript 5])[subscript 2]CHOCH(C[subscript 6]H[subscript 5])[subscript 2]. The…

  20. Enyne Metathesis Catalyzed by Ruthenium Carbene Complexes

    DEFF Research Database (Denmark)

    Poulsen, Carina Storm; Madsen, Robert

    2003-01-01

    Enyne metathesis combines an alkene and an alkyne into a 1,3-diene. The first enyne metathesis reaction catalyzed by a ruthenium carbene complex was reported in 1994. This review covers the advances in this transformation during the last eight years with particular emphasis on methodology...

  1. Mechanochemical ruthenium-catalyzed olefin metathesis.

    Science.gov (United States)

    Do, Jean-Louis; Mottillo, Cristina; Tan, Davin; Štrukil, Vjekoslav; Friščić, Tomislav

    2015-02-25

    We describe the development of a mechanochemical approach for Ru-catalyzed olefin metathesis, including cross-metathesis and ring-closing metathesis. The method uses commercially available catalysts to achieve high-yielding, rapid, room-temperature metathesis of solid or liquid olefins on a multigram scale using either no or only a catalytic amount of a liquid.

  2. Enzyme-Catalyzed Transetherification of Alkoxysilanes

    Directory of Open Access Journals (Sweden)

    Peter G. Taylor

    2013-01-01

    Full Text Available We report the first evidence of an enzyme-catalyzed transetherification of model alkoxysilanes. During an extensive enzymatic screening in the search for new biocatalysts for silicon-oxygen bond formation, we found that certain enzymes promoted the transetherification of alkoxysilanes when tert-butanol or 1-octanol were used as the reaction solvents.

  3. Dual chemistry catalyzed by human acireductone dioxygenase.

    Science.gov (United States)

    Deshpande, Aditi R; Pochapsky, Thomas C; Petsko, Gregory A; Ringe, Dagmar

    2017-03-01

    Acireductone dioxygenase (ARD) from the methionine salvage pathway of Klebsiella oxytoca is the only known naturally occurring metalloenzyme that catalyzes different reactions in vivo based solely on the identity of the divalent transition metal ion (Fe2+ or Ni2+) bound in the active site. The iron-containing isozyme catalyzes the cleavage of substrate 1,2-dihydroxy-3-keto-5-(thiomethyl)pent-1-ene (acireductone) by O2 to formate and the ketoacid precursor of methionine, whereas the nickel-containing isozyme uses the same substrates to catalyze an off-pathway shunt to form methylthiopropionate, carbon monoxide and formate. This dual chemistry was recently demonstrated in vitro by ARD from Mus musculus (MmARD), providing the first example of a mammalian ARD exhibiting metal-dependent catalysis. We now show that human ARD (HsARD) is also capable of metal-dependent dual chemistry. Recombinant HsARD was expressed and purified to obtain a homogeneous enzyme with a single transition metal ion bound. As with MmARD, the Fe2+-bound HsARD shows the highest activity and catalyzes on-pathway chemistry, whereas Ni2+, Co2+ or Mn2+ forms catalyze off-pathway chemistry. The thermal stability of the HsARD isozymes is a function of the metal ion identity, with Ni2+-bound HsARD being the most stable followed by Co2+ and Fe2+, and Mn2+-bound HsARD being the least stable. As with the bacterial ARD, solution NMR data suggest that HsARD isozymes can have significant structural differences depending upon the metal ion bound. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  4. Coumarin Compounds of Biebersteinia Multifida Roots Show Potential Anxiolytic Effects In Mice

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    Hamid Reza Monsef-Esfahani

    2013-06-01

    Full Text Available Background:Traditional preparations of the root of Biebersteinia multifida DC (Geraniaceae, a native medicinal plant of Irano-Turanian floristic region, have been used for the treatment of phobias as anxiolytic herbal preparation.Methods:We utilized the phobic behavior of mice in an elevated plus-maze as a model to evaluate the anxiolytic effect of the plant extract and bio-guided fractionation was applied to isolate the active compounds. Total root extract, alkaline and ether fraction were administered to mice at different doses 30 and 90 min prior to the maze test. Saline and diazepam were administered as negative and positive controls, respectively. The time spent in open and closed arms, an index of anxiety behavior and entry time, was measured as an index of animal activity.Results:The total root extract exhibited anxiolytic effect which was comparable to diazepam but with longer duration. This sustained effect of the crude extract was sustained for 90 min and was even more after injection of 45 mg/kg while the effect of diazepam had been reduced by 90 min. The anxiolytic effect factor was only present in the alkaline fraction and displayed its effect at lower doses than diazepam while pure vasicinone as the previously known alkaloid did not shown anxiolytic effect. The effect of the alkaline fraction was in a dose dependent manner starting at 0.2 mg/kg with a maximum at 1.0 mg/kg. Bio-guided fractionation using a variety of chromatographic methods led to isolation and purification of three coumarin derivatives from the bioactive fraction, including umbelliferone, scopoletin, and ferulic acid.Conclusion:For the first time, bio-guided fractionation of the root extract of B. multifida indicates significant sustained anxiolytic effects which led to isolation of three coumarin derivatives with well-known potent MAO inhibitory and anti-anxiety effects. These data contribute to evidence-based traditional use of B. multifida root for anxiety

  5. Coumarin compounds of Biebersteinia multifida roots show potential anxiolytic effects in mice

    Science.gov (United States)

    2013-01-01

    Background Traditional preparations of the root of Biebersteinia multifida DC (Geraniaceae), a native medicinal plant of Irano-Turanian floristic region, have been used for the treatment of phobias as anxiolytic herbal preparation. Methods We utilized the phobic behavior of mice in an elevated plus-maze as a model to evaluate the anxiolytic effect of the plant extract and bio-guided fractionation was applied to isolate the active compounds. Total root extract, alkaline and ether fraction were administered to mice at different doses 30 and 90 min prior to the maze test. Saline and diazepam were administered as negative and positive controls, respectively. The time spent in open and closed arms, an index of anxiety behavior and entry time, was measured as an index of animal activity. Results The total root extract exhibited anxiolytic effect which was comparable to diazepam but with longer duration. This sustained effect of the crude extract was sustained for 90 min and was even more after injection of 45 mg/kg while the effect of diazepam had been reduced by 90 min. The anxiolytic effect factor was only present in the alkaline fraction and displayed its effect at lower doses than diazepam while pure vasicinone as the previously known alkaloid did not shown anxiolytic effect. The effect of the alkaline fraction was in a dose dependent manner starting at 0.2 mg/kg with a maximum at 1.0 mg/kg. Bio-guided fractionation using a variety of chromatographic methods led to isolation and purification of three coumarin derivatives from the bioactive fraction, including umbelliferone, scopoletin, and ferulic acid. Conclusion For the first time, bio-guided fractionation of the root extract of B. multifida indicates significant sustained anxiolytic effects which led to isolation of three coumarin derivatives with well-known potent MAO inhibitory and anti-anxiety effects. These data contribute to evidence-based traditional use of B. multifida root for anxiety disorders. PMID

  6. In vitro assesment of anti-inflammatory activities of coumarin and Indonesian cassia extract in RAW264.7 murine macrophage cell line.

    Science.gov (United States)

    Sandhiutami, Ni Made Dwi; Moordiani, Moordiani; Laksmitawati, Dian Ratih; Fauziah, Nurul; Maesaroh, Maesaroh; Widowati, Wahyu

    2017-01-01

    Inflammation is an immune response toward injuries. Although inflammation is healing response, but in some condition it will lead to chronic disease such as rheumatoid arthritis, inflammatory bowel disease, atherosclerosis, Alzheimer's and various cancer. Indonesian cassia (Cinnamomum burmannil C. Nees & T. Ness) known to contain coumarin, is widely used for alternative medicine especially as an anti-inflammatory. This study was conducted to determine the anti-inflammatory properties of coumarin and Indonesian cassia extract (ICE) in LPS-induced RAW264.7 cell line. The cytotoxic assay of coumarin and ICE against RAW264.7 cells was conducted using MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium). The anti-inflammatory potential was determined using LPS-induced RAW 267.4 macrophages cells to measure inhibitory activity of compound and ISEon production of nitric oxide (NO), prostaglandin E2 (PGE2), and also cytokines such as interleukin-6 (IL-6), interleukin-1β (IL-1β) and TNF-α. Coumarin 10 µM and ICE 10 µg/ml were nontoxic to the RAW264.7 cells. Both of coumarin and ICE were capable to reduce the PGE2, TNF-α, NO, IL-6, and IL-β level in LPS-induced RAW264.7 cells. Coumarin had higher activity to decrease PGE2 and TNF-α, whilst ICE had higher activity to inhibit NO, IL-6, and IL-β levels. Coumarin and ICE possess anti-inflammatory properties through inhibition of PGE2 and NO along with pro-inflammatory cytokines TNF-α, IL-6, IL-1β production.

  7. In vitro assesment of anti-inflammatory activities of coumarin and Indonesian cassia extract in RAW264.7 murine macrophage cell line

    Directory of Open Access Journals (Sweden)

    Ni Made Dwi Sandhiutami

    2017-01-01

    Full Text Available Objective(s: Inflammation is an immune response toward injuries. Although inflammation is healing response, but in some condition it will lead to chronic disease such as rheumatoid arthritis, inflammatory bowel disease, atherosclerosis, Alzheimer’s and various cancer. Indonesian cassia (Cinnamomum burmanni C. Nees & T. Ness known to contain coumarin, is widely used for alternative medicine especially as an antiinflammator.This study was conducted to determine the anti-inflammatory properties of coumarin and Indonesian cassia extract (ICE in LPS-induced RAW264.7 cell line. Materials and Methods: The cytotoxic assay of coumarin and ICE against RAW264.7 cells was conducted using MTS (3-(4,5-dimethylthiazol-2-yl-5-(3-carboxymethoxyphenyl-2-(4-sulfophenyl-2H-tetrazolium. The anti-inflammatory potential was determined using LPS-induced RAW 267.4 macrophages cells to measure inhibitory activity of both compounds on production of nitric oxide (NO, prostaglandin E2 (PGE2, and also cytokines such as interleukin-6 (IL-6, interleukin-1β  (IL-1β  and TNF-α. Results: Coumarin 10 µM and ICE 10 µg/ml were nontoxic to the RAW264.7 cells. Both of coumarin and ICE were capable to reduce the PGE2, TNF-α, NO, IL-6, and IL-β level in LPS-induced RAW264.7 cells. Coumarin had higher activity to decrease PGE2 and TNF-α, whilst ICE had higher activity to inhibit NO, IL-6, and IL-β levels. Conclusion: Coumarin and ICE possess anti-inflammatory properties through inhibition of PGE2 and NO along with pro-inflammatory cytokines TNF-α, IL-6, IL-1β production.

  8. Anti-inflammatory and antioxidant effects of coumarins isolated from Foeniculum vulgare in lipopolysaccharide-stimulated macrophages and 12-O-tetradecanoylphorbol-13-acetate-stimulated mice.

    Science.gov (United States)

    Yang, In Jun; Lee, Dong Ung; Shin, Heung Mook

    2015-06-01

    Foeniculum vulgare (F. vulgare) is traditionally used to treat inflammatory diseases. Recently, anti-inflammatory and antioxidant activities of methanol extract of the fruits of F. vulgare were reported. To identify biologically active compounds responsible for the anti-inflammatory activity, we isolated four coumarins, scopoletin, 8-methoxypsoralen, bergapten and imperatorin from the fruits of F. vulgare. This study assessed the anti-inflammatory and antioxidant effects of coumarins isolated from F. vulgare in lipopolysaccharide (LPS)-stimulated macrophages and 12-O-tetradecanoylphorbol-13-acetate (TPA)-stimulated mice. RAW 264.7 cells were treated with the coumarins (30 µM) and then stimulated with LPS (100 ng/ml). Ears of ICR mice were treated with TPA (1 µg/ear) once a day. Ten microliters each of the four coumarins (200 μg/ml) were topically applied to the ears for 3 days. Antioxidant activities were examined using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis 3-ethylbenzthiazoline-6-sulfonic acid (ABTS) scavenging assays. All the tested coumarins showed excellent antioxidant activities in DPPH and ABTS radical scavenging assays. Among the coumarins, imperatorin had the greatest anti-inflammatory activities as measured by inhibition of the pro-inflammatory cytokines production including interleukin (IL)-6 and tumor necrosis factor (TNF)-α in LPS-stimulated RAW 264.7 cells through blockade of the IκB kinase (IKK)/inhibitor of kappa B (IκB)/nuclear factor-κB (NF-κB) pathway. In vivo experiments showed that imperatorin reduced TPA-induced ear thickness/weight, cutaneous cytokines expression and improved histopathological features. Although four coumarins isolated from the fruits of F. vulgare provide effective anti-inflammatory and antioxidant activities, imperatorin is most potent.

  9. Coumarin derivatives bearing benzoheterocycle moiety: synthesis, cholinesterase inhibitory, and docking simulation study

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    Kimia Hirbod

    2017-06-01

    Full Text Available Objective(s: To investigate the efficiency of a novel series of coumarin derivatives bearing benzoheterocycle moiety as novel cholinesterase inhibitors. Materials and Methods: Different 7-hydroxycoumarin derivatives were synthesized via Pechmann or Knoevenagel condensation and conjugated to different benzoheterocycle (8-hydroxyquinoline, 2-mercaptobenzoxazole or 2-mercaptobenzimidazole using dibromoalkanes 3a-m. Final compounds were evaluated against acetylcholinesterase (AChE and butyrylcholinesterase (BuChE by Ellman's method. Kinetic study of AChE inhibition and ligand-protein docking simulation were also carried out for the most potent compound 3b. Results: Some of the compounds revealed potent and selective activity against AChE. Compound 3b containing the quinoline group showed the best activity with an IC50 value of 8.80 µM against AChE. Kinetic study of AChE inhibition revealed the mixed-type inhibition of the enzyme by compound 3b. Ligand-protein docking simulation also showed that the flexibility of the hydrophobic five carbons linker allows the quinoline ring to form π-π interaction with Trp279 in the PAS. Conclusion: We suggest these synthesized compounds could become potential leads for AChE inhibition and prevention of AD symptoms.

  10. New Coumarins and Anti-Inflammatory Constituents from the Fruits of Cnidium monnieri

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    Tzong-Huei Lee

    2014-05-01

    Full Text Available The fruit of Cnidium monnieri is commercially used as healthcare products for the improvement of impotence and skin diseases. Three new coumarins, 3'-O-methylmurraol (1, rel-(1'S,2'S-1'-O-methylphlojodicarpin (2, and (1'S,2'S-1'-O-methylvaginol (3, have been isolated from the fruits of C. monnieri, together with 14 known compounds (4–17. The structures of these new compounds were determined through spectroscopic and MS analyses. Compounds 1, 4–12, and 14–17 exhibited inhibition (IC50 ≤ 7.31 µg/mL of superoxide anion generation by human neutrophils in response to formyl-l-methionyl-l-leucyl-l-phenylalanine/cytochalasin B (fMLP/CB. Compounds 7, 9–11, 15, and 17 inhibited fMLP/CB-induced elastase release with IC50 values ≤7.83 µg/mL. This investigation reveals that bioactive isolates (especially 6, 7, 14, and 17 could be further developed as potential candidates for the treatment or prevention of various inflammatory diseases.

  11. Cholinesterase Inhibition and Molecular Docking Studies of Sesquiterpene Coumarin Ethers from Heptaptera cilicica

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    Zühal Güvenalp

    2017-09-01

    Full Text Available Five sesquiterpene coumarin ethers: umbelliprenin, umbelliprenin-10',11'-monoepoxide, conferone, mogoltacin and feselol were isolated from the fruits of Heptaptera cilicica. Their structures were identified by means of spectroscopic methods. AChE and BuChE inhibitory activities of the compounds were determined by molecular docking method which were confirmed by in vitro experiments. According to molecular docking results, total score of feselol and umbelliprenin were 5.69 and 3.23 kcal/mol against acetylcholinesterase, respectively. Total score for butyrylcholinesterase inhibitory effect of them were 2.76 and 4.99 kcal/mol, respectively. Feselol and umbelliprenin exhibited significantly high inhibitory potency against acetylcholinesterase (IC 50 = 1.26 ± 0.01 and 5.86 ± 0.03 μM, respectively and butyrylcholinesterase (IC 50 = 9.98 ± 0.24 and 1.10 ± 0.19 μM, respectively. This is the first report of isolation of natural bioactives obtained from the chloroform extract of Heptaptera cilicica fruits with anticholinesterase activity.

  12. New coumarins and anti-inflammatory constituents from the fruits of Cnidium monnieri.

    Science.gov (United States)

    Lee, Tzong-Huei; Chen, Yuan-Chih; Hwang, Tsong-Long; Shu, Chih-Wen; Sung, Ping-Jyun; Lim, Yun-Ping; Kuo, Wen-Lung; Chen, Jih-Jung

    2014-05-28

    The fruit of Cnidium monnieri is commercially used as healthcare products for the improvement of impotence and skin diseases. Three new coumarins, 3'-O-methylmurraol (1), rel-(1'S,2'S)-1'-O-methylphlojodicarpin (2), and (1'S,2'S)-1'-O-methylvaginol (3), have been isolated from the fruits of C. monnieri, together with 14 known compounds (4-17). The structures of these new compounds were determined through spectroscopic and MS analyses. Compounds 1, 4-12, and 14-17 exhibited inhibition (IC50 ≤ 7.31 µg/mL) of superoxide anion generation by human neutrophils in response to formyl-l-methionyl-l-leucyl-l-phenylalanine/cytochalasin B (fMLP/CB). Compounds 7, 9-11, 15, and 17 inhibited fMLP/CB-induced elastase release with IC50 values ≤7.83 µg/mL. This investigation reveals that bioactive isolates (especially 6, 7, 14, and 17) could be further developed as potential candidates for the treatment or prevention of various inflammatory diseases.

  13. Cytotoxic activity of coumarins from the fruits of Cnidium monnieri on leukemia cell lines.

    Science.gov (United States)

    Yang, Ling-Ling; Wang, Min-Chieh; Chen, Lih-Geeng; Wang, Ching-Chiung

    2003-12-01

    Cnidii monnieri Fructus [CmF; Cnidium monnieri (L.) Cusson] is used as a tonic agent in traditional Chinese medicine. In a previous Chinese herb-cytotoxicity screening test, the ethanol extract of CmF exhibited strong effects on human leukemia (HL-60), cervical carcinoma (HeLa) and colorectal carcinoma (CoLo 205) cells. Then, the CmF extract was subjected to silica gel column chromatography and recrystallization to give five coumarins: osthol, imperatorin, bergapten, isopimpinellin, and xanthotoxin. Among these compounds, osthol showed the strongest cytotoxic activity on tumor cell lines. The structure-activity relationship established from the results indicated that the prenyl group has an important role in the cytotoxic effects. However, imperatorin showed the highest sensitivity to HL-60 cells and the least cytotoxicity to normal PBMCs. Osthol and imperatorin both caused apoptotic bodies, DNA fragmentation, and enhanced PARP degradation in HL-60 cells by biochemical analysis. These results indicate that osthol and imperatorin can induce apoptosis in HL-60 cells. Therefore, osthol and imperatorin are cytotoxic marker substances in the fruits of Cnidium monnieri.

  14. Design, Synthesis and Cytotoxicity of Novel Dihydroartemisinin-Coumarin Hybrids via Click Chemistry.

    Science.gov (United States)

    Tian, Ye; Liang, Zhen; Xu, Hang; Mou, Yanhua; Guo, Chun

    2016-06-10

    In order to develop novel chemotherapeutic agents with potent anticancer activities, we designed four series of novel compounds employing hybridization strategy. Twenty novel dihydroartemisinin-coumarin hybrids, 10a-e, 11a-e, 12a-e, 13a-e, were synthesized via click chemistry in this study and their structures were characterized by HRMS and NMR. The cytotoxic activities were measured by MTT assay against three cancer cell lines (HCT-116, MDA-MB-231, and HT-29) under normoxic or anoxic conditions, respectively. The target compounds exhibited moderate activity with IC50 values in the 0.05-125.40 μM range, and these compounds exhibited better activity against HT-29 cell line under anoxic condition. The cytotoxic activities of most compounds under anoxic condition displayed one- to 10-fold greater activity than under normoxic condition. Compounds 10a-e showed better selectivity against the HT-29 cell line than the other two cell lines. These results indicated that our design of CA IX inhibitors does correspond with its action mode to some degree and deserves further investigation.

  15. Design, Synthesis and Cytotoxicity of Novel Dihydroartemisinin-Coumarin Hybrids via Click Chemistry

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    Ye Tian

    2016-06-01

    Full Text Available In order to develop novel chemotherapeutic agents with potent anticancer activities, we designed four series of novel compounds employing hybridization strategy. Twenty novel dihydroartemisinin-coumarin hybrids, 10a–e, 11a–e, 12a–e, 13a–e, were synthesized via click chemistry in this study and their structures were characterized by HRMS and NMR. The cytotoxic activities were measured by MTT assay against three cancer cell lines (HCT-116, MDA-MB-231, and HT-29 under normoxic or anoxic conditions, respectively. The target compounds exhibited moderate activity with IC50 values in the 0.05–125.40 μM range, and these compounds exhibited better activity against HT-29 cell line under anoxic condition. The cytotoxic activities of most compounds under anoxic condition displayed one- to 10-fold greater activity than under normoxic condition. Compounds 10a–e showed better selectivity against the HT-29 cell line than the other two cell lines. These results indicated that our design of CA IX inhibitors does correspond with its action mode to some degree and deserves further investigation.

  16. Coumarins as Potential Antioxidant Agents Complemented with Suggested Mechanisms and Approved by Molecular Modeling Studies

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    Yasameen K. Al-Majedy

    2016-01-01

    Full Text Available Syntheses of coumarins, which are a structurally interesting antioxidant activity, was done in this article. The modification of 7-hydroxycoumarin by different reaction steps was done to yield target compounds. Molecular structures were characterized by different spectroscopical techniques (Fourier transformation infrared and nuclear magnetic resonance. Antioxidant activities were performed by using various in vitro spectrophometric assays against 1,1-diphenyl-2-picrylhydrazyl (DPPH radical and hydrogen peroxide (H2O2. All compounds exhibited high efficiency as antioxidants compared to ascorbic acid. The highest efficiency scavenging activity was found for compound 3 (91.0 ± 5.0, followed by compounds 2 and 4 (88.0 ± 2.00; and 87.0 ± 3.00. Ascorbic acid C was used as a standard drug with a percentage inhibition of 91.00 ± 1.5. The mechanism of the synthesized compounds as antioxidants was also studied. Hartree–Fock–based quantum chemical studies have been carried out with the basis set to 3-21G, in order to obtain information about the three-dimensional (3D geometries, electronic structure, molecular modeling, and electronic levels, namely HOMO (highest occupied molecular orbital and LUMO (lowest unoccupied molecular orbital, to understand the antioxidant activity for the synthesized compounds.

  17. Inhibition of Mild Steel Corrosion in Hydrochloric Acid Solution by New Coumarin

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    Abdul Amir H. Kadhum

    2014-06-01

    Full Text Available A new coumarin derivative, N,N′-((2E,2′E-2,2′-(1,4-phenylenebis (methanylylidenebis(hydrazinecarbonothioylbis(2-oxo-2H-chromene-3-carboxamide PMBH, was synthesized and its chemical structure was elucidated and confirmed using spectroscopic techniques (Infrared spectroscopy IR, Proton nuclear  magnetic resonance, 1H-NMR and carbon-13 nuclear magnetic resonance 13C-NMR. The corrosion inhibition effect of PMBH on mild steel in 1.0 M HCl was investigated using corrosion potential (ECORR, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS, and electrochemical frequency modulation (EFM measurements. The obtained results indicated that PMBH has promising inhibitive effects on the corrosion of mild steel in 1.0 M HCl across all of the conditions examined. Scanning electron microscopy (SEM was used to investigate the morphology of the mild steel before and after immersion in 1.0 M HCl solution containing 0.5 mM of PMBH. Surface analysis revealed improvement of corrosion resistance in presence of PMBH.

  18. Synthesis, characterization, optical properties and theoretical calculations of 6-fluoro coumarin.

    Science.gov (United States)

    Bai, Yihui; Du, Jinyan; Weng, Xuexiang

    2014-05-21

    6-Fluoro coumarin is synthesized and characterized by (1)H NMR and (13)C NMR. The optical properties of the title compound are investigated by UV-vis absorption and fluorescence emission spectra, the results show the title compound can absorb UV-vis light at 319, 269 and 215nm, moreover it exhibits blue-purple fluorescence emission at 416nm. Theoretical studies on molecular structure, infrared spectra (IR), nuclear magnetic resonance ((1)H NMR, (13)C NMR) chemical shifts, UV-vis absorption and fluorescence emission of the synthesized compound have been worked out. Most chemical calculations were performed by density functional theory (DFT) method at the B3LYP/6-311G(d,p) level (NMR at B3LYP/Aug-CC-Pvdz level) using Gaussian 09 program. The compared results reveal that the scaled theoretical vibrational frequencies are in good accordance with the observed spectra; computational chemical shifts are consistent with the experimental values in most parts, except for some minor deviations; the UV-vis absorption calculated matches the experimental one very well, and the fluorescence emission spectrum is in good agreement with the experimental one when the solute-solvent hydrogen-bonding interaction is considered. These good coincidences prove that the computational methods selected can be used to predict these properties of other similar materials where it is difficult to arrive at experimental results. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Screening of Natural Organic Volatiles from Prunus mahaleb L. Honey: Coumarin and Vomifoliol as Nonspecific Biomarkers

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    Mladenka Malenica Staver

    2011-03-01

    Full Text Available Headspace solid-phase microextraction (HS-SPME; PDMS/DVB fibre and ultrasonic solvent extraction (USE; solvent A: pentane and diethyl ether (1:2 v/v, solvent B: dichloromethane followed by gas chromatography and mass spectrometry (GC, GC-MS were used for the analysis of Prunus mahaleb L. honey samples. Screening was focused toward chemical composition of natural organic volatiles to determine if it is useful as a method of determining honey-sourcing. A total of 34 compounds were identified in the headspace and 49 in the extracts that included terpenes, norisoprenoids and benzene derivatives, followed by minor percentages of aliphatic compounds and furan derivatives. High vomifoliol percentages (10.7%–24.2% in both extracts (dominant in solvent B and coumarin (0.3%–2.4% from the extracts (more abundant in solvent A and headspace (0.9%–1.8% were considered characteristic for P. mahaleb honey and highlighted as potential nonspecific biomarkers of the honey’s botanical origin. In addition, comparison with P. mahaleb flowers, leaves, bark and wood volatiles from our previous research revealed common compounds among norisoprenoids and benzene derivatives.

  20. A coumarin-indole based colorimetric and "turn on" fluorescent probe for cyanide.

    Science.gov (United States)

    Xu, Yu; Dai, Xi; Zhao, Bao-Xiang

    2015-03-05

    A novel coumarin-indole based chemodosimeter with a simple structure was designed and prepared via a condensation reaction in high yield. The probe exhibited very high selectivity towards cyanide on both fluorescence and UV-vis spectra, which allowed it to quantitatively detect and imaging cyanide ions in organic-aqueous solution by either fluorescence enhancement or colorimetric changes. Confirmed by (1)H NMR and HRMS spectra, the detection mechanism was proved to be related with the Michael addition reaction induced by cyanide ions, which blocked the intramolecular charge transfer (ICT) of the probe. Moreover, the probe was able to be utilized efficiently in a wide pH range (7.5-10) with negligible interference from other anions and a low detection limit of 0.51μM. Application in 5 kinds of natural water source and accurate detection of cyanide in tap water solvent system also indicated the high practical significance of the probe. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Solvent effect on the relative quantum yield and fluorescence quenching of a newly synthesized coumarin derivative.

    Science.gov (United States)

    Nagaraja, D; Melavanki, R M; Patil, N R; Geethanjali, H S; Kusanur, R A

    2015-08-01

    We estimated the relative florescence quantum yield (Φ) of 8-methoxy-3-[1-(4,5-dicarbomethoxy-1,2,3-triazoloacetyl)]coumarin [8MDTC] using a single-point method with quinine sulfate in 0.1 M of sulfuric acid used as a standard reference. The fluorescence lifetimes, radiative and non-radiative decay rate constants are calculated. Relative quantum yields were found to be less in the non-polar solvents, indicating that the solute exhibits less fluorescence in a non-polar environment. The fluorescence quenching of [8MDTC] by aniline was studied at room temperature by examining the steady state in five different solvents in order to explore various possible quenching mechanisms. The experimental results show a positive deviation in Stern-Volmer plots in all solvents. Ground state complex and sphere of action static quenching models were used to interpret the results. Many quenching rate parameters were calculated using these models. The values of these parameters suggest that the sphere of action static quenching model agrees well with the experimental results. Further, a finite sink approximation model was used to check whether these bimolecular reactions were diffusion limited or not. The values of the distance parameter R' and the diffusion coefficient D were determined and are compared with the values of the encounter distance R and diffusion coefficient D calculated using the Stokes-Einstein equation. Copyright © 2014 John Wiley & Sons, Ltd.

  2. Justicia pectoralis, a coumarin medicinal plant have potential for the development of antiasthmatic drugs?

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    Luzia Kalyne Almeida Moreira Leal

    Full Text Available ABSTRACT Justicia pectoralis Jacq., Acanthaceae, is a medicinal plant found Central America. In the Northeast of Brazil, it is popularly known as “chambá” being extensively used in homemade preparations for the treatment of cough, bronchitis and asthma. The species is part of a public phytotherapy program in Brazil entitled “Farmácias Vivas”, National Record of Plants of Interest to the National Health System and the National Formulary of Herbal medicines. This paper aims to critically review the available scientific literature regarding the health promoting effects of J. pectoralis var. stenophylla. The traditional uses, phytochemistry, pharmacological activities, toxicology, quality control and potential interactions with conventional drugs were included in the present review. Botanical, chemical and pharmacognostical studies stablished several parameters useful for quality control of plant drug, extracts and phytomedicine from aerial parts of J. pectoralis using as markers two bioactive coumarins. A wide range of evidence have demonstrated the anti-inflammatory, anti-nociceptive, anti-spasmodic, smooth muscle relaxant and anxiolytic effects of J. pectoralis and its chemical constituents. Pilot clinical studies showed the efficacy of a syrup preparation of J. pectoralis in the treatment of mild and moderate asthma. The pharmacological potential make these medicinal plants good candidates for the development of new phytomedicine for the treatment of asthma. However, a strong collaboration to bridge the gap between preclinical and clinical study is still necessary for the development of an effective medicine from J. pectoralis.

  3. Antiprotozoal and Antiglycation Activities of Sesquiterpene Coumarins from Ferula narthex Exudate

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    Adnan Amin

    2016-09-01

    Full Text Available The exudate of Ferula narthex Boiss. (Apiaceae is widely used in the Indian subcontinent as a spice and because of its health effects. Six sesquiterpene coumarins have been isolated from this exudate: feselol, ligupersin A, asacoumarin A, 8′-O-acetyl-asacoumarin A, 10′R-karatavacinol and 10′R-acetyl-karatavacinol. Based on its use in infectious and diabetic conditions, the isolated constituents were evaluated for antimicrobial and antiglycation activities. Some compounds showed activity against protozoal parasites, asacoumarin A being the most active one against Plasmodium falciparum K1 (IC50 1.3 μM. With regard to antiglycation activity, in the BSA-glucose test, ligupersin A displayed the highest activity (IC50 0.41 mM, being more active than the positive control aminiguanidine (IC50 1.75 mM. In the BSA-MGO assay, the highest activity was shown by 8′-O-acetyl-asacoumarin A (IC50 1.03 mM, being less active than aminoguanidine (IC50 0.15 mM. Hence, the antiglycation activity of the isolated constituents was due to both oxidative and non-oxidative modes of inhibition.

  4. Euphorbia Species-derived Diterpenes and Coumarins as Multidrug Resistance Modulators in Human Colon Carcinoma Cells.

    Science.gov (United States)

    Wiśniewski, Jerzy; Wesołowska, Olga; Środa-Pomianek, Kamila; Paprocka, Maria; Bielawska-Pohl, Aleksandra; Krawczenko, Agnieszka; Duarte, Noelia; Ferreira, Maria-José U; Duś, Danuta; Michalak, Krystyna

    2016-05-01

    Recently, many new potent multidrug resistance (MDR) reversal agents have been discovered, among them lathyrane and jatrophane diterpenes isolated from various Euphorbia species. In the present study, the cytotoxicity, P-glycoprotein inhibition activity, and MDR reversal potency of six diterpenes and two coumarins from two Euphorbia species were studied in human colon carcinoma LoVo cells, and doxorubicin-resistant, LoVo/Dx cells. Cytotoxicity of the studied compounds (alone and in combination with doxorubicin) was investigated. Inhibition of P-glycoprotein transport activity was monitored by flow cytometry. Changes in intracellular doxorubicin accumulation were observed by means of fluorescence microscopy. Latilagascene B was demonstrated to be an effective P-glycoprotein inhibitor, able to increase doxorubicin accumulation in resistant cells, however not able to restore doxorubicin cytotoxicity in LoVo/Dx cells. The structure of latilagascene B seems to be an interesting candidate for further synthesis of new derivatives of reduced cytotoxicity and high anti-MDR potency. Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  5. Accumulation and Secretion of Coumarinolignans and other Coumarins in Arabidopsis thaliana Roots in Response to Iron Deficiency at High pH

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    Patricia Sisó-Terraza

    2016-11-01

    Full Text Available Root secretion of coumarin-phenolic type compounds has been recently shown to be related to Arabidopsis thaliana tolerance to Fe deficiency at high pH. These studies revealed the identity of a few simple coumarins occurring in roots and exudates of Fe-deficient A. thaliana plants, and left open the possible existence of other unknown phenolics. We used HPLC-UV-VIS-ESI-MS(TOF, HPLC/ESI-MSn(ion trap and HPLC-ESI-MS-MS(Q-TOF to characterize (identify and quantify phenolic-type compounds accumulated in roots or secreted into the nutrient solution of A. thaliana plants in response to Fe deficiency. Plants grown with or without Fe and using nutrient solutions buffered at pH 5.5 or 7.5 enabled to identify an array of phenolics. These include several coumarinolignans not previously reported in A. thaliana (cleomiscosins A, B, C and D and the 5’-hydroxycleomiscosins A and/or B, as well as some coumarin precursors (ferulic acid and coniferyl and sinapyl aldehydes, and previously reported cathecol (fraxetin and non-cathecol coumarins (scopoletin, isofraxidin and fraxinol, some of them in hexoside forms not previously characterized. The production and secretion of phenolics were more intense when the plant accessibility to Fe was diminished and the plant Fe status deteriorated, as it occurs when plants are grown in the absence of Fe at pH 7.5. Aglycones and hexosides of the four coumarins were abundant in roots, whereas only the aglycone forms could be quantified in the nutrient solution. A comprehensive quantification of coumarins, first carried out in this study, revealed that the catechol coumarin fraxetin was predominant in exudates (but not in roots of Fe-deficient A. thaliana plants grown at pH 7.5. Also, fraxetin was able to mobilize efficiently Fe from a Fe(III-oxide at pH 5.5 and pH 7.5. On the other hand, non-catechol coumarins were much less efficient in mobilizing Fe and were present in much lower concentrations, making unlikely that they

  6. Heterogeneously-Catalyzed Conversion of Carbohydrates

    Science.gov (United States)

    Vigier, Karine De Oliveira; Jérôme, François

    Polyfunctionality of carbohydrates and their low solubility in conventional organic solvents make rather complex their conversion to higher value added chemicals. Therefore, innovative processes are now strongly needed in order to increase the selectivity of these reactions. Here, we report an overview of the different heterogeneously-catalyzed processes described in the literature. In particular, hydrolysis, dehydration, oxidation, esterification, and etherification of carbohydrates are presented. We shall discuss the main structural parameters that need to be controlled and that permit the conversion of carbohydrates to bioproducts with good selectivity. The conversion of monosaccharides and disaccharides over solid catalysts, as well as recent advances in the heterogeneously-catalyzed conversion of cellulose, will be presented.

  7. Simultaneous assessment of absorption characteristics of coumarins from Angelicae Pubescentis Radix: In vitro transport across Caco-2 cell and in vivo pharmacokinetics in rats after oral administration.

    Science.gov (United States)

    Yang, Yan-Fang; Zhang, Lei; Zhang, You-Bo; Yang, Xiu-Wei

    2017-08-15

    Angelicae Pubescentis Radix (APR), a well-known traditional Chinese medicine, is widely used for the treatments of rheumatism and headache for centuries. To assess the absorption characteristics of coumarins from APR, a sensitive and reliable UPLC-MS/MS method was established for the simultaneous determination of sixteen coumarins from APR, including psoralen, xanthotoxin, bergapten, bergaptol, isoimperatorin, imperatorin, columbianetin, columbianetin acetate, columbianadin, oxypeucedanin hydrate, angelol B, umbelliferone, scopoletin, osthole, meranzin hydrate and nodakenetin. The specificity, linearity, sensitivity, precision, accuracy, recovery, matrix effect and stability of the method were all validated to be satisfactory. The method was then applied to the in vitro transport of APR extract (APRE) across human intestinal epithelial Caco-2 cell and in vivo pharmacokinetics in rats after oral administration of APRE. All of the tested coumarins were well or moderately absorbed across Caco-2 monolayers, and could be quickly absorbed into rat blood circulation after oral administration. Columbianetin was the most easily absorbed compound across Caco-2 cell, and also had extremely highest plasma concentration in vivo. Excellent correlation between in vitro absorption across Caco-2 cell monolayers and in vivo pharmacokinetics of coumarins from APRE was well verified. The results provided valuable information for the overall absorption characteristics of the coumarins from APR, as well as for its further studies of in vivo active substances in the further. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Nickel-catalyzed carbocyanation of alkynes

    OpenAIRE

    Nakao, Yoshiaki; Hiyama, Tamejiro

    2008-01-01

    Nickel-catalyzed carbocyanation reaction of alkynes is described. Alkynes undergo aryl- and allylcyanation reaction in the presence of nickel-phosphine catalysts to give a wide range of substituted acrylonitriles in highly stereo-, regio-, and chemoselective manners. Lewis acid cocatalysts, such as AlMe3, AlMe2Cl, and BPh3, are found to promote the arylcyanation significantly. The cooperative catalysis of nickel and Lewis acid also allows the carbocyanation reaction using alkenyl and alkyl cy...

  9. Imidazole catalyzes chlorination by unreactive primary chloramines.

    Science.gov (United States)

    Roemeling, Margo D; Williams, Jared; Beckman, Joseph S; Hurst, James K

    2015-05-01

    Hypochlorous acid and simple chloramines (RNHCl) are stable biologically derived chlorinating agents. In general, the chlorination potential of HOCl is much greater than that of RNHCl, allowing it to oxidize or chlorinate a much wider variety of reaction partners. However, in this study we demonstrate by kinetic analysis that the reactivity of RNHCl can be dramatically promoted by imidazole and histidyl model compounds via intermediary formation of the corresponding imidazole chloramines. Two biologically relevant reactions were investigated--loss of imidazole-catalyzed chlorinating capacity and phenolic ring chlorination using fluorescein and the tyrosine analog, 4-hydroxyphenylacetic acid (HPA). HOCl reacted stoichiometrically with imidazole, N-acetylhistidine (NAH), or imidazoleacetic acid to generate the corresponding imidazole chloramines which subsequently decomposed. Chloramine (NH2Cl) also underwent a markedly accelerated loss in chlorinating capacity when NAH was present, although in this case N-α-acetylhistidine chloramine (NAHCl) did not accumulate, indicating that the catalytic intermediate must be highly reactive. Mixing HOCl with 1-methylimidazole (MeIm) led to very rapid loss in chlorinating capacity via formation of a highly reactive chlorinium ion (MeImCl(+)) intermediate; this behavior suggests that the reactive forms of the analogous imidazole chloramines are their conjugate acids, e.g., the imidazolechlorinium ion (HImCl(+)). HOCl-generated imidazole chloramine (ImCl) reacted rapidly with fluorescein in a specific acid-catalyzed second-order reaction to give 3'-monochloro and 3',5'-dichloro products. Equilibrium constants for the transchlorination reactions HOCl + HIm = H2O + ImCl and NH2Cl + HIm = NH3 + ImCl were estimated from the dependence of the rate constants on [HIm]/[HOCl] and literature data. Acid catalysis again suggests that the actual chlorinating agent is HImCl(+); consistent with this interpretation, MeIm markedly catalyzed

  10. New Metabolites of Coumarin Detected in Human Urine Using Ultra Performance Liquid Chromatography/Quadrupole-Time-of-Flight Tandem Mass Spectrometry

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    Letícia Paula Leonart

    2017-11-01

    Full Text Available Coumarin (1,2-benzopyrone is a natural compound whose metabolism in humans was established in the 1970s. However, a new metabolite was recently identified in human plasma, indicating that the metabolism of coumarin has not been completely elucidated. To complement the knowledge of its metabolism, a rapid and sensitive method using UPLC-QTOF-MS was developed. A total of 12 metabolites was identified using MetaboLynxTM software, including eight metabolites not previously reported in human urine. The identified biotransformation included hydroxylation, glucuronidation, sulfation, methylation, and conjugation with N-acetylcysteine. The present work demonstrates that the metabolism study of coumarin was incomplete, possibly due to limitations of old techniques. The identification of eight inedited metabolites of such a simple molecule suggests that the information regarding the metabolism of other drugs may also be incomplete, and therefore, new investigations are necessary.

  11. Solution-phase Synthesis of a Combinatorial Library of 3-[4-(Coumarin-3-yl-1,3-thiazol-2-ylcarbamoyl]propanoic acid Amides

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    V. Chernykh

    2005-02-01

    Full Text Available The parallel solution-phase synthesis of a new combinatorial library of 3-[4-(R1-coumarin-3-yl-1,3-thiazol-2-ylcarbamoyl]propanoic acid amides 9 has been developed. The synthesis involves two steps: 1 the synthesis of core building blocks – 3- [4-(coumarin-3-yl-1,3-thiazol-2-ylcarbamoyl]propanoic acids, 6 – by the reaction of 3-(ω-bromacetylcoumarins 1 with 3-amino(thioxomethylcarbamoylpropanoic acid (5; 2 the synthesis of the corresponding 3-[4-(coumarin-3-yl-1,3-thiazol-2-yl- carbamoyl]propanoic acids amides 9 using 1,1’-carbonyldimidazole as a coupling reagent. The advantages of the method compared to existing ones are discussed.

  12. Synthesis of some 2, 6-bis (1-coumarin-2-yl-4-(4-substituted phenyl pyridine derivatives as potent biological agents

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    R. Kenchappa

    2017-02-01

    Full Text Available A convenient one-pot, three-component synthesis of 2, 6-bis (1-coumarin-2-yl-4-(4-substituted phenyl pyridine derivatives (3a–k by Chichibabin reaction has been reported. These compounds were synthesized by the reaction of 3-acetyl coumarin (1a or 5-bromo 3-acetyl coumarin (1b with substituted aromatic aldehydes (2a–k and ammonium acetate under acidic conditions and the structure was confirmed by FT-IR, 1H NMR, 13C NMR and Mass spectroscopic methods. The newly synthesized compounds (3a–k were evaluated for antimicrobial activity, DPPH free radical scavenging activity and ferrous ion-chelating ability. The mode of action of these active compounds was carried out by docking receptor GlcN6P synthase. Compounds 3a, 3b, 3c, and 3d have displayed potential antimicrobial activity and some of the compounds have shown promising antioxidant properties.

  13. Synthesis and properties of arsenic(III)-reactive coumarin-appended benzothiazolines: a new approach for inorganic arsenic detection.

    Science.gov (United States)

    Ezeh, Vivian C; Harrop, Todd C

    2013-03-04

    The EPA has established a maximum contaminant level (MCL) of 10 ppb for arsenic (As) in drinking water requiring sensitive and selective detection methodologies. To tackle this challenge, we have been active in constructing small molecules that react specifically with As(3+) to furnish a new fluorescent species (termed a chemodosimeter). We report in this contribution, the synthesis and spectroscopy of two small-molecule fluorescent probes that we term ArsenoFluors (or AFs) as As-specific chemodosimeters. The AFs (AF1 and AF2) incorporate a coumarin fluorescent reporter coupled with an As-reactive benzothiazoline functional group. AFs react with As(3+) to yield the highly fluorescent coumarin-6 dye (C6) resulting in a 20-25-fold fluorescence enhancement at λem ∼ 500 nm with detection limits of 0.14-0.23 ppb in tetrahydrofuran (THF) at 298 K. The AFs also react with common environmental As(3+) sources such as sodium arsenite in a THF/CHES (N-cyclohexyl-2-aminoethanesulfonic acid) (1:1, pH 9, 298 K) mixture resulting in a modest fluorescence turn-ON (1.5- to 3-fold) due to the quenched nature of coumarin-6 derivatives in high polarity solvents. Bulk analysis of the reaction of the AFs with As(3+) revealed that the C6 derivatives and the Schiff-base disulfide of the AFs (SB1 and SB2) are the ultimate end-products of this chemistry with the formation of C6 being the principle photoproduct responsible for the As(3+)-specific turn-ON. It appears that a likely species that is traversed in the reaction path is an As-hydride-ligand complex that is a putative intermediate in the proposed reaction path.

  14. 3D QSAR studies on binding affinities of coumarin natural products for glycosomal GAPDH of Trypanosoma cruzi

    Science.gov (United States)

    Menezes, Irwin R. A.; Lopes, Julio C. D.; Montanari, Carlos A.; Oliva, Glaucius; Pavão, Fernando; Castilho, Marcelo S.; Vieira, Paulo C.; Pupo, M.^onica T.

    2003-05-01

    Drug design strategies based on Comparative Molecular Field Analysis (CoMFA) have been used to predict the activity of new compounds. The major advantage of this approach is that it permits the analysis of a large number of quantitative descriptors and uses chemometric methods such as partial least squares (PLS) to correlate changes in bioactivity with changes in chemical structure. Because it is often difficult to rationalize all variables affecting the binding affinity of compounds using CoMFA solely, the program GRID was used to describe ligands in terms of their molecular interaction fields, MIFs. The program VolSurf that is able to compress the relevant information present in 3D maps into a few descriptors can treat these GRID fields. The binding affinities of a new set of compounds consisting of 13 coumarins, for one of which the three-dimensional ligand-enzyme bound structure is known, were studied. A final model based on the mentioned programs was independently validated by synthesizing and testing new coumarin derivatives. By relying on our knowledge of the real physical data (i.e., combining crystallographic and binding affinity results), it is also shown that ligand-based design agrees with structure-based design. The compound with the highest binding affinity was the coumarin chalepin, isolated from Rutaceae species, with an IC50 value of 55.5 μM towards the enzyme glyceraldehyde-3-phosphate dehydrogenase (gGAPDH) from glycosomes of the parasite Trypanosoma cruzi, the causative agent of Chagas' disease. The proposed models from GRID MIFs have revealed the importance of lipophilic interactions in modulating the inhibition, but without excluding the dependence on stereo-electronic properties as found from CoMFA fields.

  15. Anti-inflammatory coumarins with short- and long-chain hydrophobic groups from roots of Angelica dahurica cv. Hangbaizhi.

    Science.gov (United States)

    Wei, Wei; Wu, Xiu-Wen; Deng, Gai-Gai; Yang, Xiu-Wei

    2016-03-01

    The (1)H NMR-guided fractionation of a cyclohexane soluble portion of the 75% ethanolic extract of the roots of Angelica dahurica cv. Hangbaizhi led to the isolation of two coumarins, namely, 5-(3"-hydroxy-3"-methylbutyl)-8-hydroxyfuranocoumarin, and isobyakangelicin hydrate-3"-ethyl ether, and ten coumarins with short- or long-chain hydrophobic groups, namely, andafocoumarins A-J. Their structures were elucidated by extensive spectroscopic analyses. The absolute configurations of the C-2" secondary alcohols in ten of these compounds were deduced via the circular dichroism data of the in situ formed [Rh2(OCOCF3)4] complex, and oxidation reactions were utilized to determine location of the double bonds in the lipid chain of andafocoumarins H and I, respectively. The long-chain hydrophobic group of andafocoumarin J was determined by the method of chemical degradation and GC-MS analysis. It was the first time that coumarins with short- or long-chain hydrophobic groups in this plant had been comprehensively investigated. All isolates were assayed for their inhibitory effect against nitric oxide (NO) production in a lipopolysaccharide (LPS)-activated RAW264.7 macrophage cell line, among which andafocoumarins A and B exhibited a potent inhibition on LPS-activated NO production with IC50 values of 19.7 and 13.9 μM, respectively, indicating their stronger inhibitory activity than l-N(6)-(1-iminoethyl)-lysine (IC50=23.7 μM), a selective inhibitor of inducible nitric oxide synthase. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Catalytic Activity of Sulfated and Phosphated Catalysts towards the Synthesis of Substituted Coumarin

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    Nagi R. E. Radwan

    2018-01-01

    Full Text Available New modified acidic catalysts were prepared from the treatment of silica, titania and silica prepared from hydrolyzed tetraethyl orthosilicate (TEOS with sulfuric and phosphoric acid. The sulfated and phosphated silica synthesized from TEOS were calcined at 450 and 650 °C. These catalysts were characterized by X-ray diffraction (XRD, Fourier-transform infrared spectroscopy (FTIR, transmission electron microscope (TEM, and scanning electron microscope (SEM. The surface areas, total pore volume, and mean pore radius of the acidic catalysts were investigated, while the pore size distribution was determined by the Barrett, Joyner and Halenda (BJH method. The catalytic activity of the sulfated and phosphated silica and/or titania were examined with the Pechmann condensation reaction, in which different phenols reacted with ethyl acetoacetate as a neat reaction to obtain the corresponding coumarin derivatives. The results indicated that the treatment of the catalysts with sulfuric or phosphoric acid led to a decrease in the phases’ crystallinity to a certain degree. The morphology and the structure of the acidified catalysts were examined and their particle size was calculated. Furthermore, the amount of the used catalysts played a vital role in controlling the formation of the products as well as their performance was manipulated by the number and nature of the active acidic sites on their surfaces. The obtained results suggested that the highest catalytic conversion of the reaction was attained at 20 wt % of the catalyst and no further increase in the product yield was detected when the amount of catalyst exceeded this value. Meanwhile the phenol molecules were a key feature in obtaining the final product.

  17. Aflatoxin B1 Degradation by Stenotrophomonas Maltophilia and Other Microbes Selected Using Coumarin Medium

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    Tiangui Niu

    2008-08-01

    Full Text Available Aflatoxin B1 (AFB1 is one of the most harmful mycotoxins in animal production and food industry. A safe, effective and environmentally sound detoxification method is needed for controlling this toxin. In this study, 65 samples were screened from various sources with vast microbial populations using a newly developed medium containing coumarin as the sole carbon source. Twenty five single-colony bacterial isolates showing AFB1 reduction activity in a liquid culture medium were selected from the screen. Isolate 35-3, obtained from tapir feces and identified to be Stenotrophomonas maltophilia, reduced AFB1 by 82.5% after incubation in the liquid medium at 37 °C for 72 h. The culture supernatant of isolate 35-3 was able to degrade AFB1 effectively, whereas the viable cells and cell extracts were far less effective. Factors influencing AFB1 degradation by the culture supernatant were investigated. Activity was reduced to 60.8% and 63.5% at 20 °C and 30 °C, respectively, from 78.7% at 37 °C. The highest degradation rate was 84.8% at pH 8 and the lowest was only 14.3% at pH 4.0. Ions Mg2+ and Cu2+ were activators for AFB1 degradation, howeverï��Œion Zn2+ was a strong inhibitor. Treatments with proteinase K, proteinase K plus SDS and heating significantly reduced or eradicated the degradation activity of the culture supernatant. The results indicated that the degradation of AFB1 by S. maltophilia 35-3 was enzymatic and could have a great potential in industrial applications.

  18. QSAR and docking studies of coumarin derivatives as potent HIV-1 integrase inhibitors

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    V.K. Srivastav

    2017-02-01

    Full Text Available Human immunodeficiency virus integrase (HIV-1IN is an emerging and potential drug target for anti-HIV therapy. It is an enzyme essential for 3′ processing and integration step in the life cycle of HIV. In the present study a series of coumarin derivatives (containing 26 compounds as HIV-1IN inhibitors was subjected to quantitative structure–activity relationship (QSAR analysis. For building the regression models two different variable selection approaches namely, genetic function approximation (GFA and sequential multiple linear regression (SQ-MLR were used and compared to predict the HIV-1IN inhibition activity. Based on prediction, the best validation model for 3′ processing inhibition activity with squared correlation coefficient (r2 = 0.8965, cross validated correlation coefficient (Q2 = 0.8307 and external prediction ability pred_r2 = 0.5400 showed that Henry’s law Constant (HLC, Partition Coefficient (PC and Dipole moment-Z component (D3 were the positive contributors, whereas for integration inhibition activity, parameters r2 = 0.8904, Q2 = 0.8174 and pred_r2 = 0.7159 showed HLC, Logarithm of Partition Coefficient (LogP and Dipole moment-Y component (D2 contributed positively to the activity. The binding mode pattern of the compounds to the binding site of integrase enzyme was confirmed by docking studies. The results of the present study may be useful for designing more potent HIV-1IN inhibitors.

  19. Coumarins from the roots of Angelica dahurica cause anti-allergic inflammation.

    Science.gov (United States)

    Li, Dong; Wu, Li

    2017-07-01

    Allergic inflammation is induced by allergens and leads to various allergic diseases, including rhinitis, asthma and conjunctivitis. Histamine is important in the pathogenesis of an immunoglobulin E-dependent allergic reaction and results in the secretion of cytokines associated with inflammation. Angelica dahurica (A. dahurica) is a medicinal plant widely used in China for the treatment of symptoms related to allergic inflammation. The present study investigated the chemical constituents from A. dahurica and evaluated their reductive effect on allergic inflammation. As a result, 15 compounds including 13 coumarins have been identified as isoimperatorin (1), imperatorin (2), oxypeucedanin (3), oxypeucedanin hydrate (4), bergapten (5), byakangelicin (6), phellopterin (7), byakangelicol (8), isopimpinellin (9), xanthotoxol (10), xanthotoxin (11), pimpinellin (12), scopoletin (13), β-sitosterol (14) and daucosterol (15). Compounds 1-13 were able to reduce the release of histamine, with compounds 4-6 exhibiting the most potent activity. Furthermore, compounds 1-12 were able to inhibit the secretion of tumor necrosis factor-α, interleukin (IL)-1β and IL-4, with compounds 5 and 7 exhibiting the strongest inhibitory effects. These compounds implemented the inhibitory effects on the expression of inflammatory cytokine genes through the inhibition of nuclear factor-κB activation. Virtual screening by a docking program indicated that compound 3 is a potent histamine H1 receptor antagonist. Additionally, the calculated physicochemical properties of these compounds support most furanocoumarins to be delivered to binding sites and permeate the cell membrane. The present findings contribute to understanding how A. dahurica attenuates allergic inflammation.

  20. Growth inhibition and apoptosis induced by osthole, a natural coumarin, in hepatocellular carcinoma.

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    Lurong Zhang

    Full Text Available BACKGROUND: Hepatocellular carcinoma (HCC is one of the most commonly diagnosed tumors worldwide and is known to be resistant to conventional chemotherapy. New therapeutic strategies are urgently needed for treating HCC. Osthole, a natural coumarin derivative, has been shown to have anti-tumor activity. However, the effects of osthole on HCC have not yet been reported. METHODS AND FINDINGS: HCC cell lines were treated with osthole at various concentrations for 24, 48 and 72 hours. The proliferations of the HCC cells were measured by MTT assays. Cell cycle distribution and apoptosis were determined by flow cytometry. HCC tumor models were established in mice by subcutaneously injection of SMMC-7721 or Hepa1-6 cells and the effect of osthole on tumor growths in vivo and the drug toxicity were studied. NF-κB activity after osthole treatment was determined by electrophoretic mobility shift assays and the expression of caspase-3 was measured by western blotting. The expression levels of other apoptosis-related genes were also determined by real-time PCR (PCR array assays. Osthole displayed a dose- and time-dependent inhibition of the HCC cell proliferations in vitro. It also induced apoptosis and caused cell accumulation in G2 phase. Osthole could significantly suppress HCC tumor growth in vivo with no toxicity at the dose we used. NF-κB activity was significantly suppressed by osthole at the dose- and time-dependent manner. The cleaved caspase-3 was also increased by osthole treatment. The expression levels of some apoptosis-related genes that belong to TNF ligand family, TNF receptor family, Bcl-2 family, caspase family, TRAF family, death domain family, CIDE domain and death effector domain family and CARD family were all increased with osthole treatment. CONCLUSION: Osthole could significantly inhibit HCC growth in vitro and in vivo through cell cycle arrest and inducing apoptosis by suppressing NF-κB activity and promoting the expressions of

  1. Bioassay-guided isolation of sesquiterpene coumarins from Ferula narthex Bioss: A new anticancer agent

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    Ajmal eKhan

    2016-02-01

    Full Text Available The main objective of cancer management with chemotherapy (anticancer drugs is to kill the neoplastic (cancerous cell instead of a normal healthy cell. The bioassay-guided isolation of two new sesquiterpene coumarins (compounds 1 and 2 have been carried out from Ferula narthex collected from Chitral, locally known as Raw. Anticancer activity of crude and all fractions have been carried out to prevent carcinogenesis by using MTT assay. The n-hexane fraction showed good activity with an IC50 value of 5.434 ± 0.249 µg/mL, followed by crude MeFn extract 7.317 ± 0.535 µg/mL, and CHCl3 fraction 9.613 ± 0.548 µg/mL. Compounds 1 and 2 were isolated from chloroform fraction. Among tested pure compounds, compound 1 showed good anticancer activity with IC50 value of 14.074 ± 0.414 µg/mL. PASS (Prediction of Activity Spectra analysis of the compound 1 was carried out, in order to predicts their binding probability with anti-cancer target. As a results the compound 1 showed binding probability with human histone acetyltransferase with Pa (probability to be active value of 0.303. The compound 1 was docked against human histone acetyltransferase (anti-cancer drug target by using molecular docking simulations. Molecular docking results showed that compound 1 accommodate well in the anti-cancer drug target. Moreover the activity support cancer chemo preventive activity of different compounds isolated from the genus Ferula, in accordance with the previously reported anticancer activities of the genus.

  2. Coumarins as new matrices for matrix-assisted laser-desorption/ionization Fourier transform ion cyclotron resonance mass spectrometric analysis of hydrophobic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hang, E-mail: hangwang@sjtu.edu.cn [Instrumental Analysis Center, Shanghai Jiao Tong University, Dongchuan Road 800, Shanghai 200240 (China); Dai, Bona [Instrumental Analysis Center, Shanghai Jiao Tong University, Dongchuan Road 800, Shanghai 200240 (China); Liu, Bin [Key Laboratory of Kidney Disease Pathogenesis and Intervention of Hubei Province, College of Medicine, Hubei Polytechnic University, Huangshi, Hubei 435003 (China); Lu, Han [Department of Anesthesiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine (SJTU-SM), 197, Rui Jin Er Road, Shanghai 200025 (China)

    2015-07-02

    Highlights: • Coumarins were used as new MALDI matrices. • Coumarins were used for MALDI-FT ICR MS detection of hydrophobic compounds. • DCA had improvement in detection sensitivity, stability, selectivity and reproducibility. • DCA was applied to sterols detection in yeast cells. - Abstract: Hydrophobic compounds with hydroxyl, aldehyde or ketone groups are generally difficult to detect using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), because these compounds have low proton affinity and are poorly ionized by MALDI. Herein, coumarins have been used as new matrices for MALDI-MS analysis of a variety of hydrophobic compounds with low ionization efficiency, including steroids, coenzyme Q10, a cyclic lipopeptide and cholesterol oleate. Five coumarins, including coumarin, umbelliferone, esculetin, 7-hydroxycoumarin-3-carboxylic acid (HCA) and 6,7-dihydroxycoumarin-3-carboxylic acid (DCA), were compared with the conventional matrices of 2,5-dihydroxybenzoic acid (DHB) and α-cyano-4-hydroxycinnamic acid (CHCA). Coumarins with hydroxyl or carboxylic acid groups enabled detection. Taking DCA as an example, this matrix proved to be superior to DHB or CHCA in detection sensitivity, stability, spot-to-spot and sample-to-sample reproducibility, and accuracy. DCA increased the stability of the target compounds and decreased the loss of water. The [M + Na]{sup +} peaks were observed for all target compounds by adding NaCl as an additive, and the [M − H{sub 2}O + H]{sup +} and [M + H]{sup +} peaks decreased. DCA was selected for the identification of sterols in yeast cells, and thirteen sterols were detected by Fourier transform ion cyclotron resonance (FT ICR) mass spectrometry. This work demonstrates the potential of DCA as a new matrix for detection of hydrophobic molecules by MALDI-MS and provides an alternative tool for screening sterols in antifungal research.

  3. Effects of total coumarins of Cnidium monnieri on bone density and biomechanics of glucocorticoids-induced osteoporosis in rats.

    Science.gov (United States)

    Liao, J M; Zhu, Q A; Lu, H J; Li, Q N; Wu, T; Huang, L F

    1997-11-01

    To evaluate the effects of total coumarins from dried fruits of Cnidium monnieri (TCCM) on glucocorticoids (GC)-induced osteoporosis (OP) in rats. Single photon absorptiometric and biomechanical character measurements of femurs were used. The bone density (BD) indices in proximal, middle, and distal segments in GC group were decreased by 12% (P 0.05), and 13% (P > 0.05), respectively vs the GC group. TCCM not only prevented glucocorticoids-induced osteoporosis but also increased the torsional strength of femurs in rats.

  4. Coumarins from Cnidium monnieri (L.) and their proliferation stimulating activity on osteoblast-like UMR106 cells.

    Science.gov (United States)

    Meng, F; Xiong, Z; Sun, Y; Li, F

    2004-08-01

    The proliferation of various fractions of alcoholic extracts from fruits of Cnidium monnieri (L.) Cuss (umbelifera) were screened using the osteoblast-like UMR106 cells in vitro. The chloroform fraction from the crude extract was found to have the most stimulating activity. Three coumarins (osthole, bergapten and imperatorin) were isolated from this fraction by activity-guided assay, and their effects on osteoblastic proliferation were investigated. Osthole, a major pharmacologically active constituent, significantly promoted the cells' activity. Bergapten and imperatorin were less effective than osthole. These results suggested Cnidium monnieri (L.) Cuss extracts might have potential activity against osteoporosis, and its chloroform fraction might contain active constituents stimulating osteoblasts.

  5. Titanium catalyzed silicon nanowires and nanoplatelets

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    Mohammad A. U. Usman

    2013-03-01

    Full Text Available Silicon nanowires, nanoplatelets, and other morphologies resulted from silicon growth catalyzed by thin titanium layers. The nanowires have diameters down to 5 nm and lengths to tens of micrometers. The two-dimensional platelets, in some instances with filigreed, snow flake-like shapes, had thicknesses down to the 10 nm scale and spans to several micrometers. These platelets grew in a narrow temperature range around 900 celsius, apparently representing a new silicon crystallite morphology at this length scale. We surmise that the platelets grow with a faceted dendritic mechanism known for larger crystals nucleated by titanium silicide catalyst islands.

  6. Chiral Diamine-catalyzed Asymmetric Aldol Reaction

    Institute of Scientific and Technical Information of China (English)

    LI Hui; XU Da-zhen; WU Lu-lu; WANG Yong-mei

    2012-01-01

    A highly efficient catalytic system composed of a simple and commercially available chiral primary diamine (1R,2R)-cyclohexane-1,2-diamine(6) and trifluoroacetic acid(TFA) was employed for asymmetric Aldol reaction in i-PrOH at room temperature.A loading of 10%(molar fraction) catalyst 6 with TFA as a cocatalyst could catalyze the Aldol reactions of various ketones or aldehydes with a series of aromatic aldehydes,furnishing Aldol products in moderate to high yields(up to >99%) with enantioselectivities of up to >99% and diastereoselectivities of up to 99:1.

  7. Copper-catalyzed asymmetric oxidation of sulfides.

    Science.gov (United States)

    O'Mahony, Graham E; Ford, Alan; Maguire, Anita R

    2012-04-06

    Copper-catalyzed asymmetric sulfoxidation of aryl benzyl and aryl alkyl sulfides, using aqueous hydrogen peroxide as the oxidant, has been investigated. A relationship between the steric effects of the sulfide substituents and the enantioselectivity of the oxidation has been observed, with up to 93% ee for 2-naphthylmethyl phenyl sulfoxide, in modest yield in this instance (up to 30%). The influence of variation of solvent and ligand structure was examined, and the optimized conditions were then used to oxidize a number of aryl alkyl and aryl benzyl sulfides, producing sulfoxides in excellent yields in most cases (up to 92%), and good enantiopurities in certain cases (up to 84% ee).

  8. Biginelli Reaction Catalyzed by Copper Nanoparticles

    Science.gov (United States)

    Dewan, Manika; Kumar, Ajeet; Saxena, Amit; De, Arnab; Mozumdar, Subho

    2012-01-01

    We recently reported a novel synthesis of copper nanoparticles from copper sulphate utilizing the charge-compensatory effect of ionic liquid [bmim]BF4 and ethylene glycol. The nanoparticles were characterized and found to be stable for one year. Here we hypothesize that the stabilized nanoparticles should be able to catalyze one-pot multicomponent organic reactions. We show that the nanoparticles catalyzed Biginelli reaction at room temperature to give the product 3,4-dihydopyrimidinone (>90% yield in ∼15 minutes) from aldehydes, β-diketoester (ethylacetoacetate) and urea (or thiourea). ). Remarkably, such high yields and rapid kinetics was found to be independent of the electronic density on the reactant aryl-aldehyde. This was probably because even the surface-active particles reacted faster in the presence of ionic liquid as compared to conventional methods. The heterocyclic dihydropyrimidinones (DHPMs) and their derivatives are widely used in natural and synthetic organic chemistry due to their wide spectrum of biological and therapeutic properties (resulting from their antibacterial, antiviral, antitumor and anti-inflammatory activities. Our method has an easy work-up procedure and the nanoparticles could be recycled with minimal loss of efficiency. PMID:22912792

  9. Preparative isolation and purification of coumarins from Cnidium monnieri (L.) Cusson by high-speed counter-current chromatography.

    Science.gov (United States)

    Liu, Renmin; Feng, Lei; Sun, Ailing; Kong, Lingyi

    2004-11-05

    A high-speed counter-current chromatography (HSCCC) method for separation and purification of coumarins from Cnidium monnieri (L.) Cusson was developed by using stepwise elution with a pair of two-phase solvent system composed of light petroleum-ethyl acetate-methanol-water at volume ratios of 5:5:5:5, 5:5:6:4 and 5:5:6.5:3.5. Five kinds of coumarins were obtained and yielded 7.6 mg of xanthotoxin(I), 7.6 mg of isopimpinellin(II), 9.7 mg of bergapten(III), 60.5 mg of imperatorin(IV), 50.6 mg of osthole(V) and 10.2 mg of one unknown compound from 150mg crude sample. The purity of these compounds was 95.0%, 99.6%, 99.7%, 100%, 100% and 98.1%, respectively, as determined by HPLC. Their structures were identified by 1H NMR.

  10. Isolation of coumarins and ferulate from the roots of Angelica purpuraefolia and the antitumor activity of khellactone.

    Science.gov (United States)

    Lee, Hyeong-Kyu; Oh, Sei-Ryang; Kwon, Ok-Kyoung; Ahn, Kyoung-Seop; Lee, Joongku; Kim, Jin-Cheol; Min, Byung-Sun; Joung, Hyouk

    2007-05-01

    A new coumarin, hydroxylomatin (1), was isolated from the CHCl(3)-soluble fraction of the roots of Angelica purpuraefolia, along with one ferulate (2) and three other known coumarins (3-5) including khellactone (3). The structure of hydroxylomatin (1) was determined to be 3'beta,5'-dihydroxy-3',4'-dihydroseselin (1) by spectroscopic means including 2D-NMR. The modified Mosher's method was used to determine the chiral center at C-1 of compound 2. Khellactone (3) is a major compound of the roots of A. purpuraefolia. This study also examined the antitumor activity of khellactone (3) using a LLC mouse lung carcinoma in the BDF-1 mice and a NCI-H460 human lung carcinoma in a human tumor xenograft model in nude mice. This compound (3) inhibited LLC tumor growth with a T/C (mean value of treated group/mean value of control group) value of 12.9% at a dose of 5 mg/kg and 33.2% at a dose of 10 mg/kg, respectively, in a dose-dependent manner. In addition, it suppressed the growth of NCI-H460 tumor cells, accounting for 81.4% at a dose of 10 mg/kg in nude mice. Copyright 2007 John Wiley & Sons, Ltd.

  11. Suppressive effects of coumarins from Mammea siamensis on inducible nitric oxide synthase expression in RAW264.7 cells.

    Science.gov (United States)

    Morikawa, Toshio; Sueyoshi, Mayumi; Chaipech, Saowanee; Matsuda, Hisashi; Nomura, Yukiko; Yabe, Mikuko; Matsumoto, Tomoko; Ninomiya, Kiyofumi; Yoshikawa, Masayuki; Pongpiriyadacha, Yutana; Hayakawa, Takao; Muraoka, Osamu

    2012-08-15

    A methanol extract of the flowers of Mammea siamensis (Calophyllaceae) was found to inhibit nitric oxide (NO) production in lipopolysaccharide-activated RAW264.7 cells. From the extract, two new geranylated coumarins, mammeasins A (1) and B (2), were isolated together with 17 known compounds including 15 coumarins. The structures of 1 and 2 were determined on the basis of their spectroscopic properties as well as of their chemical evidence. Among the isolates, 1 (IC(50) = 1.8 μM), 2 (6.4 μM), surangins B (3, 5.0 μM), C (4, 6.8 μM), and D (5, 6.2 μM), kayeassamins E (7, 6.1 μM), F (8, 6.0 μM), and G (9, 0.8 μM), mammea A/AD (11, 1.3 μM), and mammea E/BB (16, 7.9 μM) showed NO production inhibitory activity. Compounds 1, 9, and 11 were found to inhibit induction of inducible nitric oxide synthase (iNOS). With regard to mechanism of action of these active constituents (1, 9, and 11), suppression of STAT1 activation is suggested to be mainly involved in their suppression of iNOS induction. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Coumarins with α-glucosidase and α-amylase inhibitory activities from the flower of Edgeworthia gardneri.

    Science.gov (United States)

    Zhao, Deng-Gao; Zhou, Ai-Yu; Du, Zhiyun; Zhang, Yu; Zhang, Kun; Ma, Yan-Yan

    2015-12-01

    The flower of Edgeworthia gardneri is consumed in beverages in Tibet and has potential health benefits for diabetes. As a part of our continuous studies on dietary supplements for diabetes, two monomers, five dimers and one trimer of coumarins were isolated from the flowers of E. gardneri. One dimer was a new compound (1) and its structure was determined by spectroscopic methods, including multiple NMR techniques and mass spectrometry. The inhibitory activities of all coumarins against α-amylase and α-glucosidase were evaluated. Compound 4 displayed potent inhibitory effect on both α-amylase and α-glucosidase, with an IC50 of 90 and 86μg/mL, respectively. The IC50 of compound 3 against α-glucosidase was 18.7μg/mL, and its inhibition mode was noncompetitive. Based on the fluorescence analysis, the binding constant and the number of binding sites of compound 3 were calculated as 2.05×10(5) and 1.24, respectively. Furthermore, the interaction between compound 3 and α-glucosidase was a spontaneous process that was driven mainly by hydrophobic force. This study could facilitate the utilization of E gardneri as functional food ingredient. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Manganese Catalyzed C–H Halogenation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wei; Groves, John T.

    2015-06-16

    The remarkable aliphatic C–H hydroxylations catalyzed by the heme-containing enzyme, cytochrome P450, have attracted sustained attention for more than four decades. The effectiveness of P450 enzymes as highly selective biocatalysts for a wide range of oxygenation reactions of complex substrates has driven chemists to develop synthetic metalloporphyrin model compounds that mimic P450 reactivity. Among various known metalloporphyrins, manganese derivatives have received considerable attention since they have been shown to be versatile and powerful mediators for alkane hydroxylation and olefin epoxidation. Mechanistic studies have shown that the key intermediates of the manganese porphyrin-catalyzed oxygenation reactions include oxo- and dioxomanganese(V) species that transfer an oxygen atom to the substrate through a hydrogen abstraction/oxygen recombination pathway known as the oxygen rebound mechanism. Application of manganese porphyrins has been largely restricted to catalysis of oxygenation reactions until recently, however, due to ultrafast oxygen transfer rates. In this Account, we discuss recently developed carbon–halogen bond formation, including fluorination reactions catalyzed by manganese porphyrins and related salen species. We found that biphasic sodium hypochlorite/manganese porphyrin systems can efficiently and selectively convert even unactivated aliphatic C–H bonds to C–Cl bonds. An understanding of this novel reactivity derived from results obtained for the oxidation of the mechanistically diagnostic substrate and radical clock, norcarane. Significantly, the oxygen rebound rate in Mn-mediated hydroxylation is highly correlated with the nature of the trans-axial ligands bound to the manganese center (L–MnV$=$O). Based on the ability of fluoride ion to decelerate the oxygen rebound step, we envisaged that a relatively long-lived substrate radical could be trapped by a Mn–F fluorine source, effecting carbon–fluorine bond

  14. Synthesis and antitumor activity of some novel thiophene, pyrimidine, coumarin, pyrazole and pyridine derivatives

    Directory of Open Access Journals (Sweden)

    Albratty Mohammed

    2017-03-01

    Full Text Available 2-Cyano-N-(thiazol-2-yl acetamide (2a and 2-cyano-N-(oxazol- 2-yl acetamide (2b were obtained via the reaction of ethyl cyanoacetate with either 2-aminothiazole (1a or 2-aminooxazole (1b. The formed products were directed toward the reaction with cyclopentanone and elemental sulfur in the presence of triethylamine to give cyclopenta[b]thiophene derivatives (3a,b. The latter products were reacted with either ethyl cyanoacetate or malononitrile to form compounds 4a,b and 5a,b, respectively. Compounds 4a,b were aimed at synthesizing some heterocyclic compounds; thus internal cyclization reactions were introduced to form compounds 6a,b. Also, compounds 4a,b reacted with salicylaldehyde, hydrazine derivatives and either urea or thiourea to produce coumarin derivatives (7a,b, pyrazole derivatives (8a-d and pyrimidine derivatives (9a-d, respectively. Reaction of either benzaldehyde or benzene diazonium chloride (11 with compounds 4a,b afforded compounds 10a,b and 12a,b, respectively. On the other hand, compounds 5a,b underwent internal cyclization to form pyrimidine derivatives 13a,b. Also, when compounds 5a,b reacted with either ethyl cyanoacetate or malononitrile, they gave pyridine derivatives (15a-d through the formation of intermediates (14a-d. Finally, formation of fused pyrimidine derivatives (17a,b was achieved through the reaction of compounds 5a,b and salicylaldehyde applying two different pathways. The first pathway used a catalytic amount of piperidine to form compounds 16a,b; the latter products underwent cyclization to give compounds 17a,b. The second pathway, using a catalytic amount of sodium ethoxide solution directly in one step, afforded compounds 17a,b. Structures of the newly synthesized compounds were established using IR, 1H NMR, 13C NMR and mass spectrometry and their antitumor activity was investigated. Some of these compounds showed promising inhibitory effects on three different cell lines. However, fused pyrimidine

  15. Quantitative analysis of alpha, beta-thujone, pulegone, safrole, coumarin and beta-asarone in alcoholic beverages by selected-ion monitoring.

    Science.gov (United States)

    Galli, C L; Galli, G; Tragni, E; Caruso, D; Fiecchi, A

    1984-10-01

    Interest in the quantitative analysis of flavouring agents in alcoholic beverages arises from the possible toxicological consequences deriving from their use. The method reported here, based on gas chromatography with selected-ion monitoring mass spectrometry (SIM), allows the simultaneous measurement of alpha, beta-thujone, pulegone, safrole, coumarin and beta-asarone at the ppb level in alcoholic beverages.

  16. Caspase-1 Specific Light-Up Probe with Aggregation-Induced Emission Characteristics for Inhibitor Screening of Coumarin-Originated Natural Products.

    Science.gov (United States)

    Lin, Hao; Yang, Haitao; Huang, Shuai; Wang, Fujia; Wang, Dong-Mei; Liu, Bin; Tang, Yi-Da; Zhang, Chong-Jing

    2018-01-11

    Caspase-1 is a key player in pyroptosis and inflammation. Caspase-1 inhibition is found to be beneficial to various diseases. Coumarin-originated natural products have an anti-inflammation function, but their direct inhibition effect to caspase-1 remains unexplored. To evaluate their interactions, the widely used commercial coumarin-based probe (Ac-YVAD-AMC) is not suitable, as the background signal from coumarin-originated natural products could interfere with the screening results. Therefore, fluorescent probes using a large Stokes shift could help solve this problem. In this work, we chose the fluorophore of tetraphenylethylene-thiophene (TPETH) with aggregation-induced emission characteristics and a large Stokes shift of about 200 nm to develop a molecular probe. Bioconjugation between TPETH and hydrophilic peptides (DDYVADC) through a thiol-ene reaction generated a light-up probe, C1-P3. The probe has little background signal in aqueous media and exerts a fluorescent turn-on effect in the presence of caspase-1. Moreover, when evaluating the inhibition potency of coumarin-originated natural products, the new probe could generate a true and objective result but not for the commercial probe (Ac-YVAD-AMC), which is evidenced by HPLC analysis. The quick light-up response and accurate screening results make C1-P3 very useful in fundamental study and inhibitior screening toward caspase-1.

  17. Drimane-type Sesquiterpene Coumarins from Ferula gummosa Fruits Enhance Doxorubicin Uptake in Doxorubicin-resistant Human Breast Cancer Cell Line

    Directory of Open Access Journals (Sweden)

    Mehrdad Iranshahi

    2014-04-01

    Full Text Available Multidrug resistance (MDR is the main cause of failure in the chemotherapy of cancer patients. The present study aimed to evaluate the effects of sesquiterpene coumarins of Ferula gummosa fruits on P-glycoprotein (P-gp–mediated MDR. Drimane-type sesquiterpene coumarins from the fruits of F. gummosa were extracted with dichloromethane and subjected to column chromatography. The effects of the isolated compounds on P-gp–mediated MDR were evaluated in the breast cancer cell line MCF-7 which shows high resistance to doxoribicin (MCF-7/Dox. Phytochemical investigation of dichloromethane extract of F. gummosa fruits resulted in three sesquiterpene coumarins including conferone (1, mogoltacin (2, and feselol (3. The structures of these compounds were confirmed by 1D and 2D Nuclear Magnetic Resonance (NMR spectroscopy. Exposure of cells to conferone, mogoltacin, feselol, and verapamil (positive control enhanced doxorubicin uptake by MCF-7/Dox cells. This effect was dose dependent, but varied with the structure of the chemical. At 25 μM, all the tested sesquiterpene coumarins restored at least 50% of the reference uptake (uptake by sensitive cells; but at 10 μM, their potency varied where conferone showed the highest potency and feselol showed the lowest potency. Conferone, mogoltacin, and feselol from F. gummosa suppress P-gp–mediated drug efflux in highly resistant human breast cancer cells.

  18. Structure-cytotoxicity relationships of a series of natural and semi-synthetic simple coumarins as assessed in two human tumour cell lines

    NARCIS (Netherlands)

    Kolodziej, H; Kayser, O; Woerdenbag, HJ; vanUden, W; Pras, N

    1997-01-01

    The cytotoxicity of 22 natural and semi-synthetic simple coumarins was evaluated in GLC(4), a human small cell lung carcinoma cell line, and in COLO 320, a human colorectal cancer cell line, using the microculture tetrazolium (MTT) assay. With IC50 values > 100 mu M, following a continuous (96h)

  19. Solvent organization around the perfluoro group of coumarin 153 governs its photophysical properties: An experimental and simulation study of coumarin dyes in ethanol as well as fluorinated ethanol solvents

    Science.gov (United States)

    Mondal, Saptarsi; Halder, Ritaban; Biswas, Biswajit; Jana, Biman; Singh, Prashant Chandra

    2016-05-01

    The self-aggregation property of the perfluoro group containing molecules makes it important in the research fields of biology and polymer and organic synthesis. In the quest of understanding the role of the perfluoro group on the photophysical properties of perfluoro-containing molecules in biologically important fluoroethanol solvents, we have applied photophysical as well as molecular dynamics simulation techniques to explore the properties of perfluoro groups containing molecule coumarin-153 (C153) in ethanol (ETH), monofluoroethanol (MFE), difluoroethanol (DFE), and trifluoroethanol (TFE) and compared them with the molecules without perfluoro moiety, namely coumarin-6H (C6H) and coumarin-480 (C480). In contrast to C6H and C480, the excited state lifetime of C153 in fluorinated ETHs is not monotonic. The excited state lifetime of C153 decreases in MFE and DFE as compared to ETH, whereas in TFE, it increases as compared to MFE and DFE. Molecular dynamics simulation reveals that the carbon terminal away from the OH group of fluorinated ETHs has a preferential orientation near the perfluoro (CF3) group of C153. In MFE and DFE, the CF3 group of C153 prefers to have a CF2—F⋯H —(CHF) type of electrostatic interaction over CF2—F⋯F —(CH2) kind of dispersion interaction which increases the rate of nonradiative decay, probably due to the electrostatic nature of the CF2—F⋯H —(CHF) hydrogen bond. On the other hand, in TFE, C—F⋯ F—C type of dispersion interaction, also known as fluorous interaction, takes place between the CF3 groups of C153 and TFE which decreases the rate of nonradiative rate as compared to MFE and DFE, leading to the increased lifetime of C153 in TFE. Photophysical and MD simulation studies clearly depict that the structural organization of solvents and their interaction with the fluorocarbon group are crucial factors for the photophysical behavior of the fluorocarbon containing molecules.

  20. Kinetics and mechanism of uncatalyzed and ruthenium(III)-catalyzed ...

    Indian Academy of Sciences (India)

    The effect of ionic strength on both uncatalyzed and catalyzed reactions was studied by varying the. NaClO4 concentration. The rate of uncatalyzed reaction was found to increase with increasing ionic strength, whereas the rate of catalyzed reaction decreases with the increase of ionic strength. Thus, the plot of ln kU.

  1. Toward Efficient Palladium-Catalyzed Allylic C-H Alkylation

    DEFF Research Database (Denmark)

    Jensen, Thomas; Fristrup, Peter

    2009-01-01

    Recent breakthroughs have proved that direct palladium (II)-catalyzed allylic C-H alkylation can be achieved. This new procedure shows that the inherent requirement for a leaving group in the Tsuji-Trost palladium-catalyzed allylic alkylation can be lifted. These initial reports hold great promise...

  2. Representing Rate Equations for Enzyme-Catalyzed Reactions

    Science.gov (United States)

    Ault, Addison

    2011-01-01

    Rate equations for enzyme-catalyzed reactions are derived and presented in a way that makes it easier for the nonspecialist to see how the rate of an enzyme-catalyzed reaction depends upon kinetic constants and concentrations. This is done with distribution equations that show how the rate of the reaction depends upon the relative quantities of…

  3. [Thymidylate synthase-catalyzed reaction mechanism].

    Science.gov (United States)

    Rode, Wojciech; Jarmuńa, Adam

    2015-01-01

    Thymidylate synthase ThyA (EC 2.1.1.45;-encoded by the Tyms gene), having been for 60 years a molecular target in chemotherapy, catalyses the dUMP pyrimidine ring C(5) methylation reaction, encompassing a transfer of one-carbon group (the methylene one, thus at the formaldehyde oxidation level) from 6R-N5,10-methylenetetrahydrofolate, coupled with a reduction of this group to the methyl one, with concomitant generation of 7,8-dihydrofolate and thymidylate. New facts are presented, concerning (i) molecular mechanism of the catalyzed reaction, including the substrate selectivity mechanism, (ii) mechanism of inhibition by a particular inhibitor, N4-hydroxy-dCMP, (iii) structural properties of the enzyme, (iv) cellular localization, (v) potential posttranslational modifications of the enzyme protein and their influence on the catalytic properties and (vi) non-catalytic activities of the enzyme.

  4. Heterogeneously Catalyzed Oxidation Reactions Using Molecular Oxygen

    DEFF Research Database (Denmark)

    Beier, Matthias Josef

    with a carboxylic acid resulting in TONs of up to 2000. In the absence of the carboxylic acid, ceria inhibited the reaction exhibiting radical scavenger properties. Contrary to p-xylene, neither ethylbenzene nor cumene conversion was promoted by ceria even in the presence of a carboxylic acid. Substantial leaching......Heterogeneously catalyzed selective oxidation reactions have attracted a lot of attention in recent time. The first part of the present thesis provides an overview over heterogeneous copper and silver catalysts for selective oxidations in the liquid phase and compared the performance and catalytic...... that both copper and silver can function as complementary catalyst materials to gold showing different catalytic properties and being more suitable for hydrocarbon oxidation reactions. Potential opportunities for future research were outlined. In an experimental study, the potential of silver as a catalyst...

  5. Lipase-catalyzed production of lysophospholipids

    Directory of Open Access Journals (Sweden)

    Mnasri Taha

    2017-07-01

    Full Text Available Lysophospholipids, such as lysophosphatidic acid or lysophosphatidylcholine, are important bioactive lipids, involved in various normal and pathological cellular processes. They also have industrial and pharmaceutical uses such as emulsifiers or components of drug delivery systems. Lipases, which natural substrates are long chain triacylglycerols, are important biocatalysts for organic synthesis mainly due to their broad substrate specificity and their ability to display high catalytic activity in organic media. This paper describes the various lipase-catalyzed reactions implemented for the production of lysophospholipids. They include hydrolysis or alcoholysis of phospholipids and acylation of the glycerophosphoryl moiety. Special emphasis is made on our work dealing with the production of lysophospholipids rich in dososahexaenoic acid, an important dietary polyunsaturated fatty acid via the hydrolysis of phospholipids extracted from the microalga Isochrysis galbana.

  6. Catalyzed modified clean fractionation of switchgrass.

    Science.gov (United States)

    Cybulska, Iwona; Brudecki, Grzegorz P; Hankerson, Brett R; Julson, James L; Lei, Hanwu

    2013-01-01

    Switchgrass was used as a lignocellulosic feedstock for second generation ethanol production, after pretreatment using sulfuric acid-catalyzed modified clean fractionation based on NREL's (National Renewable Energy Laboratory) original procedure. Optimization of temperature, catalyst concentration and solvent composition was performed using Response Surface Methodology, and 59.03 ± 7.01% lignin recovery, 84.85 ± 1.34% glucose, and 44.11 ± 3.44% aqueous fraction xylose yields were obtained at 140.00 °C, 0.46% w/w catalyst concentration, 36.71% w/w ethyl acetate concentration, and 25.00% w/w ethanol concentration. The cellulose fraction did not inhibit the fermentation performance of Saccharomyces cerevisiae and resulted in an ethanol yield of 89.60 ± 2.1%. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. 3D-QSAR and Molecular Docking Studies on the TcPMCA1-Mediated Detoxification of Scopoletin and Coumarin Derivatives

    Directory of Open Access Journals (Sweden)

    Qiu-Li Hou

    2017-06-01

    Full Text Available The carmine spider mite, Tetranychus cinnabarinus (Boisduval, is an economically important agricultural pest that is difficult to prevent and control. Scopoletin is a botanical coumarin derivative that targets Ca2+-ATPase to exert a strong acaricidal effect on carmine spider mites. In this study, the full-length cDNA sequence of a plasma membrane Ca2+-ATPase 1 gene (TcPMCA1 was cloned. The sequence contains an open reading frame of 3750 bp and encodes a putative protein of 1249 amino acids. The effects of scopoletin on TcPMCA1 expression were investigated. TcPMCA1 was significantly upregulated after it was exposed to 10%, 30%, and 50% of the lethal concentration of scopoletin. Homology modeling, molecular docking, and three-dimensional quantitative structure-activity relationships were then studied to explore the relationship between scopoletin structure and TcPMCA1-inhibiting activity of scopoletin and other 30 coumarin derivatives. Results showed that scopoletin inserts into the binding cavity and interacts with amino acid residues at the binding site of the TcPMCA1 protein through the driving forces of hydrogen bonds. Furthermore, CoMFA (comparative molecular field analysis- and CoMSIA (comparative molecular similarity index analysis-derived models showed that the steric and H-bond fields of these compounds exert important influences on the activities of the coumarin compounds.Notably, the C3, C6, and C7 positions in the skeletal structure of the coumarins are the most suitable active sites. This work provides insights into the mechanism underlying the interaction of scopoletin with TcPMCA1. The present results can improve the understanding on plasma membrane Ca2+-ATPase-mediated (PMCA-mediated detoxification of scopoletin and coumarin derivatives in T. cinnabarinus, as well as provide valuable information for the design of novel PMCA-inhibiting acaricides.

  8. New Coumarin Derivatives and Other Constituents from the Stem Bark of Zanthoxylum avicennae: Effects on Neutrophil Pro-Inflammatory Responses

    Directory of Open Access Journals (Sweden)

    Jih-Jung Chen

    2015-04-01

    Full Text Available Three new coumarin derivatives, 8-formylalloxanthoxyletin (1, avicennone (2, and (Z-avicennone (3, have been isolated from the stem bark of Zanthoxylum avicennae (Z. avicennae, together with 15 known compounds (4–18. The structures of these new compounds were determined through spectroscopic and MS analyses. Compounds 1, 4, 9, 12, and 15 exhibited inhibition (half maximal inhibitory concentration (IC50 values ≤7.65 µg/mL of superoxide anion generation by human neutrophils in response to formyl-l-methionyl-l-leucyl-l-phenylalanine/cytochalasin B (fMLP/CB. Compounds 1, 2, 4, 8 and 9 inhibited fMLP/CB-induced elastase release with IC50 values ≤8.17 µg/mL. This investigation reveals bioactive isolates (especially 1, 2, 4, 8, 9, 12 and 15 could be further developed as potential candidates for the treatment or prevention of various inflammatory diseases.

  9. New Coumarin Derivatives and Other Constituents from the Stem Bark of Zanthoxylum avicennae: Effects on Neutrophil Pro-Inflammatory Responses

    Science.gov (United States)

    Chen, Jih-Jung; Yang, Chieh-Kai; Kuo, Yueh-Hsiung; Hwang, Tsong-Long; Kuo, Wen-Lung; Lim, Yun-Ping; Sung, Ping-Jyun; Chang, Tsung-Hsien; Cheng, Ming-Jen

    2015-01-01

    Three new coumarin derivatives, 8-formylalloxanthoxyletin (1), avicennone (2), and (Z)-avicennone (3), have been isolated from the stem bark of Zanthoxylum avicennae (Z. avicennae), together with 15 known compounds (4–18). The structures of these new compounds were determined through spectroscopic and MS analyses. Compounds 1, 4, 9, 12, and 15 exhibited inhibition (half maximal inhibitory concentration (IC50) values ≤7.65 µg/mL) of superoxide anion generation by human neutrophils in response to formyl-l-methionyl-l-leucyl-l-phenylalanine/cytochalasin B (fMLP/CB). Compounds 1, 2, 4, 8 and 9 inhibited fMLP/CB-induced elastase release with IC50 values ≤8.17 µg/mL. This investigation reveals bioactive isolates (especially 1, 2, 4, 8, 9, 12 and 15) could be further developed as potential candidates for the treatment or prevention of various inflammatory diseases. PMID:25938967

  10. Design of new coumarin dyes having thiophene moieties for highly efficient organic-dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Kohjiro, Hara; Mitsuhiko, Kurashige; Kazuhiro, Sayama; Hironori, Arakawa [National Institute of Advanced Industrial Sciences and Technology, Photoreaction Control Research Center, Ibaraki (Japan); Yasufumi, Dan-Oh; Chiaki, Kasada; Akira, Shinpo; Sadaharu, Suga [Hayashibara Biochemical Laboratories, Inc., Okayama (Japan)

    2003-07-01

    We have developed new coumarin dyes having thiophene moieties in order to improve the photovoltaic performance of dye-sensitized nanocrystalline TiO{sub 2} solar cells based on the organic dyes as photo-sensitizers. A solar-energy-to-electricity conversion efficiency ({eta}) of 7.7% was attained under AM 1.5 irradiation (100 mW cm''-''2) with a short-circuit current density (J{sub s}c) of 14.3 mA cm''-''2, an open-circuit voltage (V{sub o}c) of 0.73 V, and a fill factor (ff) of 0.74. (authors)

  11. Accumulation of the coumarin scopolin under abiotic stress conditions is mediated by the Arabidopsis thaliana THO/TREX complex

    KAUST Repository

    Döll, Stefanie

    2017-12-09

    Secondary metabolites are involved in the plant stress response. Among these are scopolin and its active form scopoletin, which are coumarin derivatives associated with reactive oxygen species scavenging and pathogen defence. Here we show that scopolin accumulation can be induced in the root by osmotic stress and in the leaf by low-temperature stress in Arabidopsis thaliana. A genetic screen for altered scopolin levels in A. thaliana revealed a mutant compromised in scopolin accumulation in response to stress; the lesion was present in a homologue of THO1 coding for a subunit of the THO/TREX complex. The THO/TREX complex contributes to RNA silencing, supposedly by trafficking precursors of small RNAs. Mutants defective in THO, AGO1, SDS3 and RDR6 were impaired with respect to scopolin accumulation in response to stress, suggesting a mechanism based on RNA silencing such as the trans-acting small interfering RNA pathway, which requires THO/TREX function.

  12. [Effects of osthol and total-coumarins from Cnidium monnieri on immunological function in kidney yang deficiency mice].

    Science.gov (United States)

    Qin, L P; Wang, H B; Zhang, J Q

    1995-09-01

    Mice were injected intraperitoneally with hydrocortisone acetate to replicate the animal model of Kidney Yang Deficiency (KYD). Osthol and total-coumarins (TCR) from the fruit of Cnidium monnieri were administered orally to model mice. The effects of osthol and TCR on the immunological function of the KYD mice were observed. The results showed that compare with those in normal mice, the percentage of phagocytosis and the index of macrophage phagocytosis, the level of serum hemolysin and the proliferation of lymphocytes lowered significantly (P < 0.01) in model mice. It was shown that administering osthol or TCR could notably (P < 0.01) prevent the above-mentioned lowering in model mice, revealing that osthol and TCR could improve the immunological function of KYD mice.

  13. [Effects of coumarins from cnidium monnieri on the function of pituitary-adrenocortical axis in kidney yang deficiency rats].

    Science.gov (United States)

    Qin, L P; Zhang, J Q; Shi, H P

    1997-04-01

    To observe the effect of Cnidium monnieri in Kidney Yang Deficiency rats. Rats were injected intraperitoneally with hydrocortisone acetate to replicate the animal model of Kidney Yang Deficiency. Osthol, total-coumarins (TCR) from the fruit of Cnidium monnieri and positive control drug (PCD) were administered orally to model rats. The plasma levels of corticosterone (B), adrenocorticotropic hormone (ACTH), renin (PRA), angiotensin-II (AT-II) and aldosterone (ALD) were determined by radioimmunoassay. Compared with those in normal rats, the levels of B and ACTH in the plasma of model rats lowered significantly (P 0.05). The osthol, TCR have the effects in protecting and strengthening the function of pituitary-adrenocortex axis.

  14. [Effect of total coumarins from dried fruits of Cnidium monnieri on glucocorticoid-induced osteoporosis in rats].

    Science.gov (United States)

    Xie, H; Li, Q N; Huang, L F; Wu, T

    1994-07-01

    Twenty-four 3-month-old male SD rats were divided into 3 groups: Group 1--control (ig water). Group 2--ig prednisone 45 micrograms.kg-1 twice a week. Group 3--treated with total coumarins of dried fruits of Cnidium monnieri (L) Cuss (TCCM) and prednisone. TCCM was given ig 5 g.kg-1, 6 days per week. After 90 d, rats were killed. The proximal tibiae of rats were processed undecalcified for histomorphometric analysis. In comparison with control rats, the bone resorption was enhanced and bone formation decreased. The trabecular bone areas were characterized by reduction of 40% in rats which received prednisone. Trabecular bone areas of rats treated with TCCM increased 56% compared with rats receiving prednisone. All indices of bone histomorphometry were near to those in the control. The results showed that TCCM prevented glucocorticoid-induced osteoporosis.

  15. ÉTUDE CHIMIE PHYSIQ UE DE L’ACTIVITÉ ANTI-OXYDANTE D’UNE SERIE DE COUMARINES

    OpenAIRE

    EL-HADJ, SAID Anes

    2015-01-01

    L’objectif de ce travail est de mener une étude théorique de l'activité anti-oxydante de six composés coumarines afin de les classer par ordre de pouvoir antioxydant. L’étude a été effectuée en phase gazeuse et en solution dans des milieux de polarités différentes (benzène, acétone, méthanol, eau). Cette étude permet de mettre en évidence la facilité de formation du radical ArO. selon l’un des trois mécanismes suivants: Transfert d’atome d’hydrogène (HAT), Transfert d'électron ...

  16. Effect of light on contents of coumarin compounds in shoots of Ruta graveolens L. cultivated in vitro

    Directory of Open Access Journals (Sweden)

    Halina Ekiert

    2014-01-01

    Full Text Available Shoots of Ruta graveolens L. (Rutaceae were cultivated in stationary liquid culture under different light conditions: constant artificial light (900 lx, darkness, constant artificial light (900 ix following irradiation with UV-C light. The contents of five furanocoumarins: psoralen, bergapten, xanthotoxin, isopimpinellin and imperatorin, as well as biogenetic precursor of these metabolites, umbelliferone, were determined by HPLC method in shoots cultivated in vitro and in overground parts of plants growing in open air. It was shown that light conditions, tested in these experiments, significantly influenced contents of the metabolites in shoots cultivated in in vitro culture. Total content of the coumarin compounds in shoots cultivated under constant artificial light (900 lx was equal or higher than in plants growing under natural conditions. Therefore, it is suggested that stationary liquid shoot culture of R. graveolens. can be an alternative source for obtaining biologically active furanocoumarins.

  17. [Prescription screening of total coumarins of Angelica dahurica var. formosana extended action tablets based on artificial neural network].

    Science.gov (United States)

    Li, Ling; Li, Shi-Feng; He, Yu-Xin

    2014-05-01

    To analyze the screening of prescription for the total coumarins of Angelica dahurica var. formosana sustained release tablets, and to preliminarily discuss the releasing mechanism. On the basis of orthogonal test data, the prescriptions were screened and optimized by adopting the artificial neural network technology and by taking the in vitro release rate at the setting time as the evaluation indicator. The in vitro release performance of sustained release tablets prepared by the screened optimal technology was good, and the drugs released continuously for 12 h. The drug release process was fitted by adopting the Ritger-Peppas equation. The release of these tablets in artificial gastric juice could be described as the combined action of diffusion and skeleton dissolution. Artificial neural network technology can be used to design the pharmacy prescription, optimize the process, solve nonlinear problems with multiple factors and multiple levels, and reduce the experimental workload. So it has broad application prospect.

  18. A quick response fluorescent probe based on coumarin and quinone for glutathione and its application in living cells

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Xi [Institute of Organic Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Du, Zhi-Fang [Taishan College, Shandong University, Jinan 250100 (China); Wang, Li-Hong; Miao, Jun-Ying [Institute of Developmental Biology, School of Life Science, Shandong University, Jinan 250100 (China); Zhao, Bao-Xiang, E-mail: bxzhao@sdu.edu.cn [Institute of Organic Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China)

    2016-05-30

    We have designed and synthesized a simple but effective fluorescent probe for sensing glutathione (GSH) by PET process based on coumarin and quinone, which worked as fluorophore and reaction site, respectively. The probe could discriminate GSH from cysteine and homocysteine within 1 min in PBS-buffered solution. The sensing mechanism was confirmed by density functional theory (DFT), viscosity test, fluorescence spectrum analysis and HRMS, respectively. The probe has a low limit of detection (0.1 μM) and finally been used in cell imaging successfully. - Highlights: • This probe can discriminate glutathione from sulfhydryl compound by PET process. • This probe can be used to determine glutathione in aqueous solution within 1 min. • This probe has been successfully applied in living cell image.

  19. Synthesis of coumarin-theophylline hybrids as a new class of anti-tubercular and anti-microbial agents.

    Science.gov (United States)

    Mangasuli, Sumitra N; Hosamani, Kallappa M; Devarajegowda, Hirihalli C; Kurjogi, Mahantesh M; Joshi, Shrinivas D

    2018-02-25

    A series of novel coumarin-theophylline hybrids were synthesized and examined for their anti-tubercular activity in vitro against Mycobacterium tuberculosis H 37 Rv, anti-microbial activity in vitro against gram-positive bacteria (Staphylococcus aureus) and gram-negative bacterias (Escherichia coli, Salmonella typhi) as well as fungi (Candida albicans). The compound (3a) has shown excellent anti-tubercular activity with MIC of 0.12 μg/mL. Electron donating compounds (3a, 3f) have displayed significant anti-microbial activity. The compounds have also been precisely elucidated using single crystal X-ray diffraction techniques. Molecular docking study has been performed against 4DQU enzyme of Mycobacterium tuberculosis showed good binding interactions and is in agreement with the in vitro results. Copyright © 2018. Published by Elsevier Masson SAS.

  20. Photochemical cleavage of individual stereoisomers of coumarin-5-fluorouracil crossdimers via single- and two-photon-absorption

    Science.gov (United States)

    Behrendt, Philipp J.; Kim, Hee-Cheol; Hampp, Norbert

    2013-11-01

    Coumarin-5-fluorouracil crossdimers were photochemically synthesized. Three different isomers were isolated and their photo-cycloreversion, induced by single- and two-photon-absorption, was studied. The single-photon absorption quantum yields strongly correlate with the dipole moments and the absorption behavior of the stereoisomers. Between the stereoisomers a maximal factor of 6.5 in cyclobutane cleavage efficiency is observed. The two-photon-absorption cross-sections were determined for all three stereoisomers. A good correlation between the single and two-photon-absorption cross-sections was found. The isomer with the highest light sensitivity is the syn-head-to-head isomer. For most applications, isomer pure preparations seem advisable as the required light intensities may be reduced significantly.

  1. Determination of dipole moment change on the electronic excitation of isolated Coumarin 153 by pendular-state spectroscopy

    Science.gov (United States)

    Kanya, Reika; Ohshima, Yasuhiro

    2003-03-01

    The change (Δ μ) in the permanent dipole moment on the S 1←S 0 electronic excitation is determined for Coumarin 153 (C153) in a molecular beam from the spectral change induced by applying a strong dc electric field up to 200 kV/cm. The comparison of the observed fluorescence excitation spectra under various external fields with the corresponding simulations for a pendular-state molecule yields Δμ=7.1±0.4 D for both the syn and anti conformers of C153. Previous experimental results on Δ μ in the condensed phase, as well as the theoretical predictions reported in the literature, are discussed on the basis of the present value under an isolated condition.

  2. Separation of 20 coumarin derivatives using the capillary electrophoresis method optimized by a series of Doehlert experimental designs.

    Science.gov (United States)

    Woźniakiewicz, Michał; Gładysz, Marta; Nowak, Paweł M; Kędzior, Justyna; Kościelniak, Paweł

    2017-05-15

    The aim of this study was to develop the first CE-based method enabling separation of 20 structurally similar coumarin derivatives. To facilitate method optimization a series of three consequent Doehlert experimental designs with the response surface methodology was employed, using number of peaks and the adjusted time of analysis as the selected responses. Initially, three variables were examined: buffer pH, ionic strength and temperature (No. 1 Doehlert design). The optimal conditions provided only partial separation, on that account, several buffer additives were examined at the next step: organic cosolvents and cyclodextrin (No. 2 Doehlert design). The optimal cyclodextrin type was also selected experimentally. The most promising results were obtained for the buffers fortified with methanol, acetonitrile and heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin. Since these additives may potentially affect acid-base equilibrium and ionization state of analytes, the third Doehlert design (No. 3) was used to reconcile concentration of these additives with optimal pH. Ultimately, the total separation of all 20 compounds was achieved using the borate buffer at basic pH 9.5 in the presence of 10mM cyclodextrin, 9% (v/v) acetonitrile and 36% (v/v) methanol. Identity of all compounds was confirmed using the in-lab build UV-VIS spectra library. The developed method succeeded in identification of coumarin derivatives in three real samples. It demonstrates a huge resolving power of CE assisted by addition of cyclodextrins and organic cosolvents. Our unique optimization approach, based on the three Doehlert designs, seems to be prospective for future applications of this technique. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Isolation of new monoterpene coumarins from Micromelum minutum leaves and their cytotoxic activity against Leishmania major and cancer cells.

    Science.gov (United States)

    Sakunpak, A; Matsunami, K; Otsuka, H; Panichayupakaranant, P

    2013-08-15

    On the basis of a leishmanicidal assay-guided isolation, two new monoterpene coumarins, minutin A and minutin B, were purified from Micromelum minutum leaves together with four known coumarins, 8,4″-dihydroxy-3″,4″-dihydrocapnolactone-2',3'-diol, 8-hydroxyisocapnolactone-2',3'-diol, 8-hydroxy-3″,4″-dihydrocapnolactone-2',3'-diol, and clauslactone E. Among these compounds, minutin A, minutin B, 8-hydroxyisocapnolactone-2',3'-diol and clauslactone E showed a significant cytotoxic activity against Leishmania major with IC50 values of 26.2, 20.2, 12.1, and 9.8 μM, respectively, while 8,4″-dihydroxy-3″4″-dihydrocapnolactone-2',3'-diol and 8-hydroxy-3″,4″-dihydrocapnolactone-2',3'-diol were not active. However, all these compounds exhibited some inhibitory activity against one or more lung adenocarcinoma (SBC3 and A549) and leukaemia (K562, and K562/ADM) cell lines. Amongst these, clauslactone E, minutin B and 8-hydroxyisocapnolactone-2',3'-diol possessed the strongest cytotoxic activity against SBC3, A549, K562, and K562/ADM cell lines, with IC50 values of 3.7, 10.4, 12.1, and 10.8 μM for clauslactone E; 9.6, 17.5, 8.7 and 6.7 μM for minutin B; 8.8, 10.1, 16.9, and 10.1 μM for 8-hydroxyisocapnolactone-2',3'-diol, respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Cytochrome P450 isoenzymes in rat and human liver microsomes associate with the metabolism of total coumarins in Fructus Cnidii.

    Science.gov (United States)

    Hu, Xiao; Huang, Wei; Yang, Yuan

    2015-12-01

    Fructus Cnidii (Cnidium) is isolated from the dry and ripe fruit of Cnidium monnier (L.) Cuss (umbelifera), an annual herb. It is demonstrated that the active constituents of Fructus Cnidii are coumarins, known as Total Coumarins of Cnidium Monnier (TCCM). Osthole (Ost) and imperatorin (Imp) are the most active constituents of TCCM which are usually regarded as the quality indicators of medicinal Fructus Cnidii. The aim is to study the metabolism of Fructus Cnidii effective monomer osthole and imperatorin in vitro by liver microsomes. CYP3A4 inhibitor ketoconazole, CYP2D6 inhibitor qunidine, CYP2C8 inhibitor trimethoprim, CYP2C9 inhibitor sulfaphenazole, and CYP1A2 inhibitor α-naphthoflavone were used to investigate the metabolism from incubation time, substrate concentration and liver microsomal concentration, respectively. The concentration of liver microsomes was 0.2 mg/ml. Ost (0.8/3.2/12.8 uM) was incubated at 37 °C for 20 min while Imp (1.6/6.4/19.2 uM) was incubated for 30 min. Qunidine, trimethoprim and α-naphthoflavone could significantly inhibit the disappearance of Imp; meanwhile ketoconazole, sulfaphenazole and qunidine could inhibit the disappearance of Ost. CYP1A, CYP2C are involved in the metabolism of Imp and CYP3A mediates the metabolism of Ost in rat liver microsomes. In human liver microsomes, CYP1A2, CYP2C8, CYP2D6 are involved in the metabolism of Imp; CYP3A4 is involved in the metabolism of Ost at all the tested concentrations of Ost, while CYP2C9, CYP2D6 mediate the metabolism at high concentration of Ost.

  5. Thermodynamic and kinetic study of chiral separations of coumarin-based anticoagulants on derivatized amylose stationary phase.

    Science.gov (United States)

    Gebreyohannes, Kahsay G; McGuffin, Victoria L

    2010-09-17

    Thermodynamic and kinetic studies are performed on amylose derivatized with tris-(3,5-dimethylphenyl carbamate) stationary phase for the chiral separation of coumarin-based anticoagulants. Polar-organic eluents that contain acetonitrile as bulk solvent with modifiers such as methanol, i-butanol, t-butanol, and tetrahydrofuran are used in the study. Temperature is varied from 5 to 45 degrees C at constant pressure of 1500psi. In general, both retention and enantioselectivity decrease as the temperature increases and as hydrogen bond donating ability of the modifiers increases. The van't Hoff plots are found to show both linear and non-linear behavior. The non-linear plots are believed to be the result of conformational changes in the derivatized amylose phase and are observed around room temperature. The retention behavior in acetonitrile mobile phase provides a linear enthalpy-entropy compensation plot, indicating that all coumarins may have a similar retention mechanism. In contrast, enthalpy-entropy compensation is not observed for warfarin and coumatetralyl enantiomers when separated with different organic modifiers in the mobile phase. The kinetic data indicate that the rate of sorption is always greater than the rate of desorption. An increase in the concentration of alcohol modifiers causes an increase in the desorption rate constant. In contrast, an increase in the concentration of tetrahydrofuran causes a decrease in the desorption rate constant. This effect is most significant for the second eluted enantiomer of coumatetralyl, for which the desorption rate is 36 times slower than the first eluted enantiomer. 2010 Elsevier B.V. All rights reserved.

  6. Mechanisms of bacterially catalyzed reductive dehalogenation

    Energy Technology Data Exchange (ETDEWEB)

    Picardal, Flynn William [Univ. of Arizona, Tucson, AZ (United States)

    1992-01-01

    Nine bacteria were tested for the ability to dehalogenate tetrachloromethane (CT), tetrachloroethene (PCE), and 1, 1, 1-trichloroethane (TCA) under anaerobic conditions. Three bacteria were able to reductively dehalogenate CT. Dehalogenation ability was not readily linked to a common metabolism or changes in culture redox potential. None of the bacteria tested were able to dehalogenate PCE or TCA. One of the bacteria capable of dehalogenating CT, Shewanella putrefaciens, was chosen as a model organism to study mechanisms of bacterially catalyzed reductive dehalogenation. The effect of a variety of alternate electron acceptors on CT dehalogenation ability by S. putrefaciens was determined. oxygen and nitrogen oxides were inhibitory but Fe (III), trimethylamine oxide, and fumarate were not. A model of the electron transport chain of S. putrefaciens was developed to explain inhibition patterns. A period of microaerobic growth prior to CT exposure increased the ability of S. putrefaciens to dehalogenate CT. A microaerobic growth period also increased cytochrome concentrations. A relationship between cytochrome content and dehalogenation ability was developed from studies in which cytochrome concentrations in S. putrefaciens were manipulated by changing growth conditions. Stoichiometry studies using 14C-CT suggested that CT was first reduced to form a trichloromethyl radical. Reduction of the radical to produce chloroform and reaction of the radical with cellular biochemicals explained observed product distributions. Carbon dioxide or other fully dehalogenated products were not found.

  7. Zinc catalyzed Guanylation reaction of Amines with Carbodiimides ...

    Indian Academy of Sciences (India)

    016-1096-y. Zinc catalyzed Guanylation reaction of Amines with Carbodiimides/. Isocyanate leading to Guanidines/Urea derivatives formation. JAYEETA BHATTACHARJEE, MITALI SACHDEVA, INDRANI BANERJEE and. TARUN K PANDA.

  8. Platinum-Catalyzed Selective Tin-Carbon Bond Formation

    NARCIS (Netherlands)

    Thoonen, Sander Hendrikus Lambertus

    2003-01-01

    In conclusion, two improved methods for the selective synthesis of monoorganotin trihalides were developed. The platinum-catalyzed Kocheshkov redistribution reaction of dialkyltin dichlorides with tin tetrachloride is the most interesting. Contrary to the other two methods described (the direct

  9. Aerobic Oxidation of Alcohols to Carbonyl Compounds Catalyzed by ...

    Indian Academy of Sciences (India)

    hydroxyphthalimide (NHPI) com- bined with cobalt porphyrin intercalated heterogeneous hybrid catalyst (CoTPP-Zn2Al-LDH) has been devel- oped. The results showed that this catalytic system can effectively catalyze the oxidation of alcohols to the.

  10. Hydrolysis of Toxic Natural Glucosides Catalyzed by Cyclodextrin Dicyanohydrins

    DEFF Research Database (Denmark)

    Bjerre, Jeannette; Nielsen, Erik Holm; Bols, Mikael

    2008-01-01

    The hydrolysis of toxic 7-hydroxycoumarin glucosides and other aryl and alkyl glucosides, catalyzed by modified a- and ß-cyclodextrin dicyanohydrins, was investigated using different UV, redox, or HPAEC detection assays. The catalyzed reactions all followed Michaelis-Menten kinetics, and an impre......The hydrolysis of toxic 7-hydroxycoumarin glucosides and other aryl and alkyl glucosides, catalyzed by modified a- and ß-cyclodextrin dicyanohydrins, was investigated using different UV, redox, or HPAEC detection assays. The catalyzed reactions all followed Michaelis-Menten kinetics...... degree of catalysis was also found for the toxic hydroxycoumarin esculin. A novel synthesized diaminomethyl ß-cyclodextrin showed a weak catalysis of p-nitrophenyl ß-D-glucopyranoside hydrolysis....

  11. Copper-Catalyzed Alkylation of Benzoxazoles with Secondary Alkyl Halides

    OpenAIRE

    Ren P; Salihu I; Scopelliti R.; Hu XL

    2012-01-01

    Copper catalyzed direct alkylation of benzoxazoles using nonactivated secondary alkyl halides has been developed. The best catalyst is a new copper(I) complex (1) and the reactions are promoted by bis[2 (NN dimethylamino)ethyl] ether.

  12. Dirhodium-catalyzed C-H arene amination using hydroxylamines

    National Research Council Canada - National Science Library

    Paudyal, Mahesh P; Adebesin, Adeniyi Michael; Burt, Scott R; Ess, Daniel H; Ma, Zhiwei; Kürti, László; Falck, John R

    2016-01-01

    .... Here, we present a mild dirhodium-catalyzed C-H amination for conversion of structurally diverse monocyclic and fused aromatics to the corresponding primary and N-alkyl arylamines using NH2/NH(alkyl)-O-(sulfonyl...

  13. Aerobic Oxidation of Alcohols to Carbonyl Compounds Catalyzed by ...

    Indian Academy of Sciences (India)

    NHPI) combined with cobalt porphyrin intercalated heterogeneous hybrid catalyst (CoTPP-Zn2Al-LDH) has been developed. The results showed that this catalytic system can effectively catalyze the oxidation of alcohols to thecorresponding ...

  14. Oxidations catalyzed by phenylacetone monooxygenase from Thermobifida fusca

    NARCIS (Netherlands)

    Gonzalo, Gonzalo de; Torres Pazmino, Daniel; Ottolina, Gianluca; Fraaije, Marco W.; Carrea, Giacomo

    2005-01-01

    Several organic sulfides, ketones and other organic systems have been tested as substrates in oxidation reactions catalyzed by the recently discovered phenylacetone monooxygenase from Thermobifida fusca. The biocatalytic properties of this Baeyer–Villiger monooxygenase have been studied, revealing

  15. Nickel-catalyzed direct synthesis of dialkoxymethane ethers

    Indian Academy of Sciences (India)

    catalyzed direct synthesis of dialkoxymethane ethers. MURUGAN SUBARAMANIAN ABHIJIT BERA BHAGAVATULA L V PRASAD EKAMBARAM BALARAMAN. RAPID COMMUNICATION Volume 129 Issue 8 August 2017 pp 1153-1159 ...

  16. Ni-catalyzed reductive addition of alkyl halides to isocyanides.

    Science.gov (United States)

    Wang, Bo; Dai, Yijing; Tong, Weiqi; Gong, Hegui

    2015-12-21

    This paper highlights Ni-catalyzed reductive trapping of secondary and tertiary alkyl radicals with both electron-rich and electron-deficient aryl isocyanides using zinc as the terminal reductant, affording 6-alkylated phenanthridine in good yields. The employment of carbene ligands necessitates the alkyl radical process, and represents the first utility in the Ni-catalyzed reductive conditions for the generation of unactivated alkyl radicals from the halide precursors.

  17. Hemoglobin and Red Blood Cells Catalyze Atom Transfer Radical Polymerization

    OpenAIRE

    Silva Tilana B.; Spulber Mariana; Kocik Marzena K.; Seidi Farzad; Charan Himanshu; Rother Martin; Sigg Severin J.; Renggli Kasper; Kali Gergely; Bruns Nico

    2013-01-01

    Hemoglobin (Hb) is a promiscuous protein that not only transports oxygen but also catalyzes several biotransformations. A novel in vitro catalytic activity of Hb is described. Bovine Hb and human erythrocytes were found to display ATRPase activity i.e. they catalyzed the polymerization of vinyl monomers under conditions typical for atom transfer radical polymerization (ATRP). N isopropylacrylamide (NIPAAm) poly(ethylene glycol) methyl ether acrylate (PEGA) and poly(ethylene glycol) methyl eth...

  18. Density Functional Theory (DFT Study of Coumarin-based Dyes Adsorbed on TiO2 Nanoclusters—Applications to Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Mihai A. Gîrţu

    2013-06-01

    Full Text Available Coumarin-based dyes have been successfully used in dye-sensitized solar cells, leading to photovoltaic conversion efficiencies of up to about 8%. Given the need to better understand the behavior of the dye adsorbed on the TiO2 nanoparticle, we report results of density functional theory (DFT and time-dependent DFT (TD-DFT studies of several coumarin-based dyes, as well as complex systems consisting of the dye bound to a TiO2 cluster. We provide the electronic structure and simulated UV-Vis spectra of the dyes alone and adsorbed to the cluster and discuss the matching with the solar spectrum. We display the energy level diagrams and the electron density of the key molecular orbitals and analyze the electron transfer from the dye to the oxide. Finally, we compare our theoretical results with the experimental data available and discuss the key issues that influence the device performance.

  19. Conservation Kickstart- Catalyzing Conservation Initiatives Worldwide

    Science.gov (United States)

    Treinish, G.

    2014-12-01

    Adventurers and Scientists for Conservation (ASC) is a nonprofit organization that collects environmental data to catalyze conservation initiatives worldwide. Adventure athletes have the skills and motivation to reach the most remote corners of the world. ASC utilizes those skills to provide the scientific community with data while providing the outdoor community with purpose beyond the personal high of reaching a summit or rowing across an ocean. We carefully select projects, choosing partnerships that will maximize the impact of ASC volunteers. Each project must have a clear path to a tangible conservation outcome and demonstrate a clear need for our brand of volunteers. We partner with government agencies, universities, and independant reseachers to kickstart data collection efforts around the world. Last year, through a partnership with the Olympic National Forest, 20 volunteers from the Seattle area set up and monitored camera traps in an effort to survey for costal Pacific marten. Our work led to the species' listing as "critically imperiled" with NatureServe. A partnership with the inaugural Great Pacific Race, engaging trans-Pacific rowing teams, searched for microplastics in the Pacific Ocean as part of our ongoing microplastics campaign. In a multi-year partnership with the American Prairie Reserve (APR), ASC volunteer crews live and work on the Reserve collecting wildlife data year round. The data we obtain directly informs the Reserve's wildlife management decisions. On this project, our crews have safely and effectively navigated temperature extremes from -30 degrees to 100+ degrees while traveling in a remote location. We are currently scouting projects in the Okavango Delta of Botswana and the rainforest of Suriname where we will be able to cover large amounts of area in a short periord of time. ASC is at the crossroads of the adventure and coservation science communities. Our approach of answering specific questions by using highly skilled and

  20. Evaluation of the Potential Use of Laminar Extrudates on Stabilizing Micronized Coumarin Particles by Supercritical Fluids (RESS)-Study of Different RESS Processing Variables and Mode of Operation.

    Science.gov (United States)

    Oliveira, Gonçalo E; Pinto, João F

    2017-10-01

    The study evaluates the ability of extrudates to deliver coumarin particles micronized by the rapid expansion of supercritical solutions (RESS). The RESS parameters were drug load (2-50 g), pressure (15-42 MPa) and temperature (40-60°C) in the extraction and pressure in the expansion (0.1-5 MPa) chambers in batch or continuous and CO 2 flow rate in the continuous mode of operation. Particles were characterized for size (laser diffractometry, optical and electronic microscopies-19-61 μm), surface area (BET-0.282-0.423 m 2 /g), density (pycnometry-1.273-1.358 g/cm 3 ) and yield (2-70%). Extrudates were characterized for the force of extrusion (4 kN), release of coumarin (100%/24 h) and mechanical properties (bending strength and stiffness increased, whereas elasticity decreased in storage) and X-ray diffractometry (micronized particles and extrudates have shown identical patterns) and calorimetry (DSC, enthalpies increased on storage). In the discontinuous mode of operation, increased loads in the extraction or increased pressure in the expansion chambers led to larger particles, whereas increased temperature and pressure in the extraction chamber led to smaller particles. In the continuous mode of operation, a decrease on the expansion pressure, load and CO 2 flow rate led to increased yields. An increase on the flow rate led to a decrease on the particles' diameter, but an increase on coumarin load in the extraction chamber led to an increase in diameter. The study has identified the key parameters in RESS continuous and discontinuous modes of operation affecting the properties of the micronized coumarin particles and has proved the ability of extrudates with a laminar shape on delivering micronized particles.

  1. Coumarin or benzoxazinone bearing benzimidazolium and bis(benzimidazolium) salts; involvement in transfer hydrogenation of acetophenone derivatives and hCA inhibition

    OpenAIRE

    Mert Olgun Karataş; Serkan Dayan; Nilgün Kayacı; Çiğdem Bilen; Emre Yavuz; Nahit Gencer; Bülent Alıcı; Nilgün Ozpozan Kalaycıoğlu; Oktay Arslan

    2015-01-01

    Four new salts of benzimidazolium and bis(benzimidazolium) which include coumarin or benzoxazinone moieties were synthesized and the structures of the newly synthesized compounds were elucidated on the basis of spectral analyses such as 1H-NMR, 13C-NMR, HSQC, IR, LC-MS and elemental analysis. Benzimidazolium salts were used intensively as N-heterocyclic carbene (NHC) precursors in the various catalytic reactions such as transfer hydrogenation (TH), C-H bond activation, Heck, Suzuki reaction e...

  2. Studies on Dental Caries Prevention by Traditional Medicines (IX) : Potent Antibacterial Action of Coumarin Derivatives from Licorice Roots against Streptococcus mutans

    OpenAIRE

    MASAO, HATTORI; KUMI, MIYAHCI; YUE-ZHONG, SHU; NOBUKO, KAKIUCHI; TSUNEO, NAMBA; Research Institute for Wakan-Yaku (Oriental Medicine), Toyama Medical and Pharmaceutical University; Research Institute for Wakan-Yaku (Oriental Medicine), Toyama Medical and Pharmaceutical University; Research Institute for Wakan-Yaku (Oriental Medicine), Toyama Medical and Pharmaceutical University; Research Institute for Wakan-Yaku (Oriental Medicine), Toyama Medical and Pharmaceutical University; Research Institute for Wakan-Yaku (Oriental Medicine), Toyama Medical and Pharmaceutical University

    1986-01-01

    Glycyrol, glycyrin, isoglycyrol and glycycoumarin isolated from the methanolic extract of licorice roots (Glycyrrhiza uralensis FISCH. et DC, Leguminosae) had potent antibacterial action against a cariogenic bacterium, Streptococcus mutatis. The former two compounds completely inhibited the bacterial growth at 6.25 μg/ml and the latter two at 12.5 μg/ml, determined by the tube dilution technique. The four coumarins were contained only in the licorice roots from the northeast and southeast reg...

  3. Preparation of dry extract of Mikania glomerata Sprengel (Guaco) and determination of its coumarin levels by spectrophotometry and HPLC-UV.

    Science.gov (United States)

    Soares e Silva, Luciana Soares E; da Santos da Silva, Luciane Santos; Brumano, Larissa; Stringheta, Paulo César; Aparecida de Oliveira Pinto, Miriam; Moreira Dias, Leticia Oliveira; de Sá Martins Muller, Camila; Scio, Elita; Fabri, Rodrigo Luiz; Castro, Helena C; da Penha Henriques do Amaral, Maria

    2012-08-29

    Guaco (Mikania glomerata Sprengel) syrup is one of the most popular herbal medicines used to treat the symptoms of asthmatic bronchitis, cough and hoarseness. The coumarin 2H-1-benzopyran-2-one, is one of the major constituents of Guaco and contributes to its pharmacological effects. The pharmaceutical capsule form of dry extract of Guaco is recommended by the Brazilian Program of Medicinal Plants and Herbal Medicines and used in primary health care. In order to identify a new protocol to obtain the raw material for Guaco capsule production we evaluated two methods, including a freezedrying process (lyophilization) and the spray-dryer technique, as well as the use of two adjuvants, Maltodextrins and Aerosil®, in different concentrations. The coumarin levels of the dried extracts were analyzed by UV-spectrophotometry and HPLC-UV/DAD. The adjuvant Aerosil® 8% showed better dry powder physical appearance. Lyophilization was observed to be the best process to obtain the dry extract of Guaco based on the measured coumarin levels.

  4. Preparation of Dry Extract of Mikania glomerata Sprengel (Guaco and Determination of Its Coumarin Levels by Spectrophotometry and HPLC-UV

    Directory of Open Access Journals (Sweden)

    Maria da Penha Henriques do Amaral

    2012-08-01

    Full Text Available Guaco (Mikania glomerata Sprengel syrup is one of the most popular herbal medicines used to treat the symptoms of asthmatic bronchitis, cough and hoarseness. The coumarin 2H-1-benzopyran-2-one, is one of the major constituents of Guaco and contributes to its pharmacological effects. The pharmaceutical capsule form of dry extract of Guaco is recommended by the Brazilian Program of Medicinal Plants and Herbal Medicines and used in primary health care. In order to identify a new protocol to obtain the raw material for Guaco capsule production we evaluated two methods, including a freeze-drying process (lyophilization and the spray-dryer technique, as well as the use of two adjuvants, Maltodextrins and Aerosil®, in different concentrations. The coumarin levels of the dried extracts were analyzed by UV-spectrophotometry and HPLC-UV/DAD. The adjuvant Aerosil® 8% showed better dry powder physical appearance. Lyophilization was observed to be the best process to obtain the dry extract of Guaco based on the measured coumarin levels.

  5. Extraction time and temperature affect the extraction efficiencies of coumarin and phenylpropanoids from Cinnamomum cassia bark using a microwave-assisted extraction method.

    Science.gov (United States)

    Kim, Jung-Hoon

    2017-09-15

    Microwave-assisted extraction (MAE), an efficient extraction tool, was employed to extract a coumarin and five phenylpropanoids (cinnamic acid, cinnamyl alcohol, cinnamaldehyde, 2-hydroxycinnamadehyde, and 2-methoxycinnamaldehyde) from Cinnamomum cassia bark using water as the extraction solvent. Six marker compounds were quantified by high-performance liquid chromatography-diode array detector using a validated analytical method. To investigate the influences of temperature and time on the extraction yields of the six marker compounds, the water extracts of C. cassia bark were prepared using a MAE method at six different extraction temperatures (70, 75, 80, 85, 90, and 95°C) and times (2, 4, 6, 8, 10, and 12min). Their influences were assessed by multiple regression analysis. The results obtained demonstrated that higher extraction temperature and longer extraction time positively affected coumarin and cinnamyl alcohol contents, but negatively affected extract contents of cinnamic acid, cinnamaldehyde and 2-hydroxycinnamaldehyde (all p-extraction of 2-methoxycinnamaldehyde was affected by both positively and negatively by increasing temperature and time. These changes during MAE were assumed by the chemical natures of the marker compounds with various functional groups. In conclusion, temperature and times significantly affected the extraction efficiencies of a coumarin and five phenylpropanoids from C. cassia bark when a water-based MAE method was used. This study provides a novel approach to the preparation of the water extract of C. cassia bark using MAE. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Simultaneous separation and purification of five bioactive coumarins from the Chinese medicinal plant Cnidium monnieri by high-speed counter-current chromatography.

    Science.gov (United States)

    Li, Hua-Bin; Chen, Feng

    2005-02-01

    Cnidium monnieri (L.) Cusson is a well-known Chinese medicinal plant, which has been used for the treatment of impotence, frigidity, and skin-related diseases, and exhibits strong antipruritic, antiallergic, antidermatophytic, antibacterial, antifungal, and antiosteoporotic activities. A high-speed counter-current chromatography method was developed for the separation and purification of five bioactive coumarins from this plant. The crude coumarins were obtained by ethanol extraction from the dried fruits of Cnidium monnieri (L.) Cusson under sonication. High-speed counter-current chromatography with the two-phase solvent systems n-hexane-ethyl acetate-ethanol-water (5:5:4:6, v/v) and n-hexane-ethyl acetate-ethanol-water (5:5:6:4, v/v) was successfully performed with stepwise elution. The five relatively pure coumarins were obtained from 500 mg of the crude extract in a single run. Their purities were 90.6-98.9%, and the recoveries were 85.7-94.2%.

  7. Bimolecular electron transfer reactions in coumarin amine systems: Donor acceptor orientational effect on diffusion-controlled reaction rates

    Science.gov (United States)

    Satpati, A. K.; Nath, S.; Kumbhakar, M.; Maity, D. K.; Senthilkumar, S.; Pal, H.

    2008-04-01

    Electron transfer (ET) reactions between excited coumarin dyes and different aliphatic amine (AlA) and aromatic amine (ArA) donors have been investigated in acetonitrile solution using steady-state (SS) and time-resolved (TR) fluorescence quenching measurements. No ground state complex or emissive exciplex formation has been indicated in these systems. SS and TR measurements give similar quenching constants ( kq) for each of the coumarin-amine pairs, suggesting dynamic nature of interaction in these systems. On correlating kq values with the free energy changes (Δ G0) of the ET reactions show the typical Rehm-Weller type of behavior as expected for bimolecular ET reactions under diffusive condition, where kq increases with -Δ G0 at the lower exergonicity (-Δ G0) region but ultimately saturate to a diffusion-limited value (kqDC) at the higher exergonicity region. It is, however, interestingly observed that the kqDC values vary largely depending on the type of the amines used. Thus, kqDC is much higher with ArAs than AlAs. Similarly, the kqDC for cyclic monoamine 1-azabicyclo-[2,2,2]-octane (ABCO) is distinctly lower and that for cyclic diamine 1,4-diazabicyclo-[2,2,2]-octane (DABCO) is distinctly higher than the kqDC value obtained for other noncyclic AlAs. These differences in the kqDC values have been rationalized on the basis of the differences in the orientational restrictions involved in the ET reactions with different types of amines. As understood, n-type donors (AlAs) introduce large orientational restriction and thus significantly reduces the ET efficiency in comparison to the π-type donors (ArAs). Structural constrains are inferred to be the reason for the differences in the kqDC values involving ABCO, DABCO donors in comparison to other noncyclic AlAs. Supportive evidence for the orientational restrictions involving different types of amines donors has also been obtained from DFT based quantum chemical calculations on the molecular orbitals of

  8. Catalyzed precipitation in Al-Cu-Si

    Science.gov (United States)

    Mitlin, D.; Morris, J. W.; Radmilovic, V.

    2000-11-01

    The work reported here concerns the effect of Si on the precipitation of θ' phase (metastable Al2Cu) during the isothermal aging of Al-2Cu-1 Si (wt pct). The binary alloys Al-2Cu and Al-1 Si were studied for comparison. Only two precipitate phases were detected: essentially pure Si in Al-1 Si and Al-2Cu-1 Si, and θ' (metastable Al2Cu) in Al-2Cu and Al-2Cu-1Si. On aging the ternary alloy at 225 °C, Si precipitates first and catalyzes the θ' phase. The precipitates in the ternary alloy are smaller, are more densely distributed, have lower aspect ratios, and coarsen more slowly than those in the binary Al-2Cu aged at the same temperature. While the shapes of individual θ' precipitates in binary Al-2Cu are strongly affected by the kinetic problem of nucleating growth ledges, which produces a significant scatter in the aspect ratio for samples of given thickness, the overall evolution of particle shape with size follows the predictions of the Khachaturyan-Hairapetyan (KH) thermoelastic theory, which reduces to κ= L/d ∞ √ L at large sizes. The KH theory provides an estimate for the interfacial tension of the broad Al- θ' interface of 85 to 96 mJ/m2, which is near the values for other low-energy interfaces in Al, such as the twin boundary energy (100 mJ/m2) and the antiphase boundary energy in δ' Al3Li (70 mJ/m2). Si and θ' precipitates in Al-2Cu-1 Si have a strong elastic interaction because of their compensating strain fields. This elastic interaction promotes the nucleation of θ' precipitates on Si, decreases the expected aspect ratio of θ', and inhibits coarsening. Finally, Si precipitation in ternary Al-2Cu-1 Si differs from that in binary Al-1 Si in that the Si precipitates are coarser, more equiaxed, and more extensively twinned. These changes appear to be effects of Cu, which increases the solubility of Si in Al and adsorbs on the Si-Al interface, promoting twinning by a “step-poisoning” effect at the interface.

  9. Coumarin-indole conjugate donor-acceptor system: Synthesis, photophysical properties, anion sensing ability, theoretical and biological activity studies of two coumarin-indole based push-pull dyes

    Science.gov (United States)

    Aksungur, Tuğçe; Aydıner, Burcu; Seferoğlu, Nurgül; Özkütük, Müjgan; Arslan, Leyla; Reis, Yasemin; Açık, Leyla; Seferoğlu, Zeynel

    2017-11-01

    Two coumarin-indole conjugate fluorescent dyes having donor-acceptor-donor (D-A-D) (CI-1 and CI-2) were synthesized, and characterized using IR, 1H/13C NMR and HRMS. The absorption and emission properties of the dyes were determined in different solvents. The anion sensitivity and selectivity of the dyes were studied with some anions (CN-, F-, AcO-, Cl-, Br-, I-, HSO4- and H2PO4-) in DMSO, and their interaction mechanisms were evaluated by spectrophotometric and 1H NMR titration techniques. In addition, the molecular and electronic structures of CI-1, as well as the molecular complexes of CI-1, formed with the anions (F- and AcO-), were obtained theoretically and confirmed by DFT and TD-DFT calculations. CI-1 behaves as a colorimetric chemosensor for selective and sensitive detection of CN- in DMSO/H2O (9:1) over other competing anions such as F- and AcO-. However, only CN- interacts with chromophore CI-2 via Michael addition and the main absorption maxima shifts hypsochromically with an observed distinctive color change from orange to yellow. For using as a optic dye, the thermal stability properties of the dyes was determined by TGA (Thermal Gravimetric Analysis). Antimicrobial, antifungal and DNA-ligand interaction studies of the dyes were also examined. The dyes cause conformational changes on DNA and selectively bind to nucleotides of A/A and G/G.

  10. New fluorescent probes of the hydroxyl radical: characterisation and modelization of the reactivity of coumarin derivatives with HO; Developpement de sondes fluorescentes du radical hydroxyle: caracterisation et modelisation de la reactivite de molecules derivees de la coumarine avec HO

    Energy Technology Data Exchange (ETDEWEB)

    Louit, G.

    2005-10-15

    The hydroxyl radical is involved in a wide range of different fields, from oxidative stress to atmospheric chemistry. In addition to the study of oxidative damage in biological media, the hydroxyl radical detection allows to perform a dosimetry when it is produced by ionising radiation. The aims of this work have been double: - to improve the detection of the hydroxyl radical by the design of new probes - to improve knowledge on the reactive pathways in which the hydroxyl radical is involved. We have studied the coumarin molecule, as well as 6 derivatives that we have synthesised, as fluorescent probes of the hydroxyl radical. Firstly, fluorescence spectroscopy and HPLC chromatography have allowed the evaluation of the sensibility and selectivity of detection of the probes. Consequently to this study, two applications have been developed, concerning the determination of rate constants by competition kinetics and bidimensional dosimetry. Secondly, we have studied the reactivity of the hydroxyl radical through the regioselectivity of its addition on the aromatic cycle. This problem was addressed by the combined use of experimental methods such as time resolved kinetics and HPLC along with interpretation from classical and ab initio modelization. (author)

  11. Triazole tethered isatin-coumarin based molecular hybrids as novel antitubulin agents: Design, synthesis, biological investigation and docking studies.

    Science.gov (United States)

    Singh, Harbinder; Singh, Jatinder V; Gupta, Manish K; Saxena, Ajit K; Sharma, Sahil; Nepali, Kunal; Bedi, Preet Mohinder S

    2017-09-01

    In an attempt to develop potent anti-tubulin agents against most dreadful disease cancer, a library of 28 novel triazole tethered isatin-coumarin hybrids were synthesized by click chemistry approach. Synthesized hybrids were characterized and evaluated against a panel of human cancer cell lines viz. THP-1, COLO-205, HCT-116 and PC-3. Biological assay unveiled that, compounds A-1 to A-6, B-1 to B-4 and C-1 to C-3 displayed significant inhibitory potential against THP-1, COLO-205 and HCT-116 cell lines which were more sensitive towards the designed hybrids. PC-3 among these cell lines was found to be almost resistant. Established SAR revealed marked dependence of the cytotoxic activity on the type of substituent on isatin and the length of carbon-bridge connecting isatin moiety with triazole ring. Unsubstituted isatin and two carbon-bridge were found to be crucial for cytotoxicity. Three most potent hybrids (A-1, A-2 and B-1) were further tested for tubulin polymerization inhibition. Among these three compounds, A-1 found to be endowed with most prominent tubulin polymerization inhibition potential with IC 50 value of 1.06µM which was further confirmed by using confocal microscopy. Possible binding interactions between the most potent hybrid molecule A-1 and tubulin were also divulged by molecular modeling studies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. A coumarin based Schiff base probe for selective fluorescence detection of Al3 + and its application in live cell imaging

    Science.gov (United States)

    Sen, Bhaskar; Sheet, Sanjoy Kumar; Thounaojam, Romita; Jamatia, Ramen; Pal, Amarta Kumar; Aguan, Kripamoy; Khatua, Snehadrinarayan

    2017-02-01

    A new coumarin based Schiff base compound, CSB-1 has been synthesized to detect metal ion based on the chelation enhanced fluorescence (CHEF). The cation binding properties of CSB-1 was thoroughly examined in UV-vis and fluorescence spectroscopy. In fluorescence spectroscopy the compound showed high selectivity toward Al3 + ion and the Al3 + can be quantified in mixed aqueous buffer solution (MeOH: 0.01 M HEPES Buffer; 9:1; v/v) at pH 7.4 as well as in BSA media. The fluorescence intensity of CSB-1 was enhanced by 24 fold after addition of only five equivalents of Al3 +. The fluorescence titration of CSB-1 with Al3 + in mixed aqueous buffer afforded a binding constant, Ka = (1.06 ± 0.2) × 104 M- 1. The colour change from light yellow to colourless and the appearance of blue fluorescence, which can be observed by the naked eye, provides a real-time method for Al3 + sensing. Further the live cell imaging study indicated that the detection of intracellular Al3 + ions are also readily possible in living cell.

  13. Microwave assisted synthesis, spectroscopic, electrochemical and DNA cleavage studies of lanthanide(III) complexes with coumarin based imines.

    Science.gov (United States)

    Kapoor, Puja; Fahmi, Nighat; Singh, R V

    2011-12-01

    The present work stems from our interest in the synthesis, characterization and biological evaluation of lanthanide(III) complexes of a class of coumarin based imines which have been prepared by the interaction of hydrated lanthanide(III) chloride with the sodium salts of 3-acetylcoumarin thiosemicarbazone (ACTSZH) and 3-acetylcoumarin semicarbazone (ACSZH) in 1:3 molar ratio using thermal as well as microwave method. Characterization of the ligands as well as the metal complexes have been carried out by elemental analysis, melting point determinations, molecular weight determinations, magnetic moment, molar conductance, IR, (1)H NMR, (13)C NMR, electronic, EPR, X-ray powder diffraction and mass spectral studies. Spectral studies confirm ligands to be monofunctional bidentate and octahedral environment around metal ions. The redox behavior of one of the synthesized metal complex was investigated by cyclic voltammetry. Further, free ligands and their metal complexes have been screened for their antimicrobial as well as DNA cleavage activity. The results of these findings have been presented and discussed. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Binding of Coumarin 334 with β-Cyclodextrin and with C-Hexylpyrogallol[4]arene: Opposite Fluorescence Behavior

    Directory of Open Access Journals (Sweden)

    Chandrasekaran Sowrirajan

    2013-01-01

    Full Text Available We report here the structure of the host-guest complexes of Coumarin 334 (C334 with β-cyclodextrin (β-CD and with C-hexylpyrogallol[4]arene (C-HPA and the effect of acidity on the neutral-cation equilibrium of C334 in water and in the presence of the host molecules. The structures of the host-guest complexes are proposed on the basis of the change of fluorescence on the addition of β-CD or C-HPA to C334 and by 2D ROESY spectroscopy. Opposite fluorescence behaviors, that is, quenching of fluorescence in β-CD and enhancement of fluorescence in C-HPA are observed. Time-resolved fluorescence analysis is done for the complexation, and biexponential decay pattern is observed. The possible strong inclusion complexation with C-HPA is explained. The ground and the excited state pKa values for the protonation equilibrium of C334 in water and the difficulty of protonation in the presence of the host molecules are discussed.

  15. Synthesis, Leishmanicidal and Cytotoxic Activity of Triclosan-Chalcone, Triclosan-Chromone and Triclosan-Coumarin Hybrids

    Directory of Open Access Journals (Sweden)

    Elver Otero

    2014-08-01

    Full Text Available Twelve hybrids derived from triclosan were obtained via Williamson etherification of O-triclosan alkyl bromide plus chalcone and O-coumarin or O-chromone alkyl bromide plus triclosan, respectively. Structures of the products were elucidated by spectroscopic analysis. The synthesized compounds were evaluated for antileishmanial activity against L. (V panamensis amastigotes. Cytotoxic activity was also evaluated against mammalian U-937 cells. Compounds 7–9 and 17, were active against Leishmania parasites (EC50 = 9.4; 10.2; 13.5 and 27.5 µg/mL, respectively and showed no toxicity toward mammalian cells (>200 µg/mL. They are potential candidates for antileishmanial drug development. Compounds 25–27, were active and cytotoxic. Further studies using other cell types are needed in order to discriminate whether the toxicity shown by these compounds is against tumor or non-tumor cells. The results indicate that compounds containing small alkyl chains show better selectivity indices. Moreover, Michael acceptor moieties may modify both the leishmanicidal activity and cytotoxicity. Further studies are required to evaluate if the in vitro activity against Leishmania panamensis demonstrated here is also observed in vivo.

  16. Development of an in Silico Model of DPPH• Free Radical Scavenging Capacity: Prediction of Antioxidant Activity of Coumarin Type Compounds

    Directory of Open Access Journals (Sweden)

    Elizabeth Goya Jorge

    2016-06-01

    Full Text Available A quantitative structure-activity relationship (QSAR study of the 2,2-diphenyl-l-picrylhydrazyl (DPPH• radical scavenging ability of 1373 chemical compounds, using DRAGON molecular descriptors (MD and the neural network technique, a technique based on the multilayer multilayer perceptron (MLP, was developed. The built model demonstrated a satisfactory performance for the training ( R 2 = 0.713 and test set ( Q ext 2 = 0.654 , respectively. To gain greater insight on the relevance of the MD contained in the MLP model, sensitivity and principal component analyses were performed. Moreover, structural and mechanistic interpretation was carried out to comprehend the relationship of the variables in the model with the modeled property. The constructed MLP model was employed to predict the radical scavenging ability for a group of coumarin-type compounds. Finally, in order to validate the model’s predictions, an in vitro assay for one of the compounds (4-hydroxycoumarin was performed, showing a satisfactory proximity between the experimental and predicted pIC50 values.

  17. Effect of NaCl Salts on the Activation Energy of Excited-State Proton Transfer Reaction of Coumarin 183.

    Science.gov (United States)

    Joung, Joonyoung F; Kim, Sangin; Park, Sungnam

    2015-12-17

    Coumarin 183 (C183) was used as a photoacid to study excited-state proton transfer (ESPT) reactions. Here, we studied the effect of ions on the ESPT of C183 in aqueous NaCl solutions using a steady-state fluorescence spectroscopy and time-correlated single photon counting (TCSPC) method. The acid dissociation equilibrium of excited-state C183 and the activation energy for the ESPT of C183 were determined as a function of NaCl concentration. The change in the equilibrium constant was found to be correlated with the solvation energy of deprotonated C183. Frequency-resolved TCSPC signals measured at several temperatures were analyzed by using a global fitting analysis method which enabled us to extract all the rate constants involving the ESPT reaction and the spectra of individual species. The activation energy for the ESPT reaction of C183 was highly dependent on NaCl concentration. Quantum chemical calculations were used to calculate the local hydrogen-bond (H-bond) configurations around C183 in aqueous NaCl solutions. It was found that the activation energy for the ESPT was determined by the local H-bond configurations around C183 which were significantly influenced by the dissolved ions.

  18. Synthesis, Structural Elucidation, and Antibacterial Evaluation of Some New Molecules Derived from Coumarin, 1,3,4-Oxadiazole, and Acetamide

    Directory of Open Access Journals (Sweden)

    Shahid Rasool

    2016-01-01

    Full Text Available Because of the reported biological activities of coumarin, 1,3,4-oxadiazole, and acetamides, some new compounds incorporating these moieties were synthesized and evaluated for their biological potential against Gram-positive and Gram-negative bacteria. In the present work, 4-chlororesorcinol (1 and ethyl acetoacetate (2 were mixed in a strong acidic medium to synthesize 6-chloro-7-hydroxy-4-methyl-2-oxo-2H-chromene (3 which was subjected to the intermolecular cyclization after consecutive three steps to synthesize 5-[(6-chloro-4-methyl-2-oxo-2H-chromen-7-yloxy]methyl-1,3,4-oxadiazol-2-thiol (6. A series of acetamoyl electrophiles, 8a–o, were synthesized from aralkyl/alkyl/aryl amines, 7a–o, in an aqueous basic medium. The final compounds, 9a–o, were synthesized by the reaction of compounds 6 and 8a–o in DMF/NaH. The synthesized compounds were structurally elucidated by spectral data analysis of IR, 1H-NMR, and EIMS. The most of the synthesized compounds remained moderate to excellent antibacterial agents. The molecules, 9e, 9j, and 9k, were the most efficient ones against all the five bacterial strains taken into account.

  19. Tetra-, Penta- and Hexa-Coordinated Transition Metal Complexes Constructed from Coumarin-Containing N2O2 Ligand

    Directory of Open Access Journals (Sweden)

    Lei Gao

    2018-02-01

    Full Text Available Three newly designed complexes, [Cu(L]·CHCl3 (1, [Co(L(MeOH]·CHCl3 (2 and [{Ni(L(MeOH(PhCOO}2Ni] (3 a coumarin-containing Salamo-type chelating ligand (H2L have been synthesized and characterized by elemental analyses, IR and UV-VIS spectra, and X-ray crystallography. Complex 1 includes one Cu(II atom, one completely deprotonated (L2− unit and one crystalling chloroform molecule, the Cu(II atom shows a square-planar geometry. Complex 2 includes one Co(II atom, one completely deprotonated (L2− unit, one coordinated methanol molecule and one crystalling chloroform molecule. The Co(II atom is a distorted trigonal-bipyramidal geometry. While complex 3 includes three Ni(II atoms, two completely deprotonated (L2− units, two benzoates and two coordinated methanol molecules. The complexes 1 and 2 are both possess three-dimensional supra-molecular structures by abundant noncovalent interactions. But, complex 3 formed a two-dimensional supra-molecular structure by intra-molecular hydrogen bonds. In addition, the antimicrobial and fluorescence properties of H2L and its complexes 1, 2 and 3 were also investigated.

  20. 3D-quantitative structure-activity relationship and docking studies of coumarin derivatives as tissue kallikrein 7 inhibitors.

    Science.gov (United States)

    Zheng, Xin; He, Mengxi; Tan, Xiao; Zheng, Jun; Wang, Fangyu; Liu, Sen

    2017-09-01

    Kallikrein 7 (KLK7) is a secreted serine protease that plays important roles in skin desquamation and tumour progression, which makes it an attracting drug target. To guide the design of KLK7 inhibitors, a series of coumarin-based inhibitors were used to perform 3D-quantitative structure-activity relationship analysis. 3D conformations of 37 inhibitors were generated and used to construct CoMFA and CoMSIA models. Then a complex model between the inhibitors and KLK7 was built with molecular docking. With the training set, the CoMFA and CoMSIA models achieved q2 values of 0.521 and 0.498, and r2 values of 0.942 and 0.983, respectively. With the testing set, the predicted r2 values were 0.663 and 0.669, respectively, for CoMFA and CoMSIA. 3D contour maps from these two models identified steric and hydrophobic interactions as the most important molecular features of these inhibitors. Furthermore, molecular docking study was performed to understand the binding modes between these compounds and KLK7, in which the critical steric and hydrophobic interactions between the inhibitors and KLK7 were confirmed. Steric and hydrophobic interactions are critical in the efficient binding of KLK7 inhibitors. Our analysis would provide a meaningful guideline for the rational design of novel KLK7 inhibitors. © 2017 Royal Pharmaceutical Society.

  1. The Synthesis of a Coumarin Carbohydrazide Dinuclear Copper Complex Based Fluorescence Probe and Its Detection of Thiols.

    Directory of Open Access Journals (Sweden)

    Guangjie He

    Full Text Available Small-molecule thiols, such as cysteine (CYS and glutathione (GSH, are essential for maintaining the cellular redox environment and play important roles in regulating various cellular physiological functions. A fluorescence probe (compound 1-Cu2+ for thiols based on coumarin carbohydrazide dinuclear copper complex was developed. Compound 1 was synthesized from the reaction of 7-(diethylamino-2-oxo-2H-chromene-3-carbohydrazide with 4-tert-butyl-2,6- diformylphenol. Accordingly, the copper complex (compound 1-Cu2+ was prepared by mixing compound 1 with 2 equivalents copper ions. Compound 1 had strong fluorescence while compound 1-Cu2+ hardly possessed fluorescence owing to the quenching nature of paramagnetism Cu2+ to the fluorescence molecule excited state. However, the fluorescence intensity of compound 1-Cu2+ was increased dramatically after the addition of thiol-containing amino acids, but not the other non-sulfhydryl amino acids. UV-vis absorption and fluorescence spectra indicated that compound 1-Cu2+ had good selectivity and sensitivity for thiols such as glutathione in CH3CN:H2O (3:2, v/v PBS solution. The fluorescence imaging experiments implied that compound 1-Cu2+ has potential application in thiol-containing amino acids detection in living cells.

  2. New Limonoids from Hortia oreadica and Unexpected Coumarin from H. superba Using Chromatography over Cleaning Sephadex with Sodium Hypochlorite

    Directory of Open Access Journals (Sweden)

    Vanessa G.P. Severino

    2014-08-01

    Full Text Available Previous investigations of H. oreadica reported the presence of a wide spectrum of complex limonoids and dihydrocinnamic acids. Our interest in the Rutaceae motivated a reinvestigation of H. oreadica, H. brasiliana and H. superba searching for other secondary metabolites present in substantial amounts for taxonomic analysis. In a continuation of the investigation of the H. oreadica, three new limonoids have now been isolated 9α-hydroxyhortiolide A, 11β-hydroxyhortiolide C and 1(S*-acetoxy-7(R*-hydroxy-7-deoxoinchangin. All the isolated compounds from the Hortia species reinforce its position in the Rutaceae. With regard to limonoids the genus produces highly specialized compounds, whose structural variations do not occur in any other member of the Rutaceae, thus, it is evident from limonoid data that Hortia takes an isolated position within the family. In addition, H. superba afforded the unexpected coumarin 5-chloro-8-methoxy-psoralen, which may not be a genuine natural product. Solid-state cross-polarisation/magic-angle-spinning 13C nuclear magnetic resonance, X-Ray fluorescence and Field-emission gun scanning electron microscopy experiments show that the Sephadex LH-20 was modified after treatment with NaOCl, suggesting that when xanthotoxin (8-methoxy-psoralen was extracted from cleaning of the gel column, chlorination of the aromatic system occurred.

  3. Ab initio QM/MM excited-state molecular dynamics study of coumarin 151 in water solution

    Science.gov (United States)

    Kina, Daisuke; Arora, Pooja; Nakayama, Akira; Noro, Takeshi; Gordon, Mark S.; Taketsugu, Tetsuya

    Ab initio molecular dynamics (AIMD) simulations are performed to investigate the excited state dynamics of coumarin 151 (C151) in the gas phase and in water solution at the CASSCF level of theory with segmented DZP basis sets, where in the latter case effective fragment potentials (EFP) are used. The dipole moment of an isolated C151 molecule increases considerably upon electronic vertical excitation, from 5.0 D (S0 state) to 11.1 D (S1 state). Two equilibrium structures have been identified in the S1 state, i.e., a charge-transfer state with a planar amino group and a deformed structure of the six-membered ring with the carbonyl group, and a structure that is similar to the S0 equilibrium structure. In AIMD simulations for an isolated C151 molecule (presumably similar to dynamics in nonpolar solvents), C151 decays from S1 to S0 via a crossing point of the charge-transfer state in some trajectories, while in the AIMD simulations for C151-EFP (including solvent), the S1 and S0 energies show an almost parallel energy variation with structural changes, and no crossing point is observed. This result is in good agreement with the experimental observation.

  4. Using experimental studies and theoretical calculations to analyze the molecular mechanism of coumarin, p-hydroxybenzoic acid, and cinnamic acid

    Science.gov (United States)

    Hsieh, Tiane-Jye; Su, Chia-Ching; Chen, Chung-Yi; Liou, Chyong-Huey; Lu, Li-Hwa

    2005-05-01

    Three natural products, Coumarin ( 1), p-hydroxybenzoic acid ( 2), trans-cinnamic acid ( 3) were isolated from the natural plant of indigenous cinnamon and the structures including relative stereochemistry were elucidated on the basis of spectroscopic data and theoretical calculations. Their sterochemical structures were determined by NMR spectroscopy, mass spectroscopy, and X-ray crystallography. The p-hydroxybenzoic acid complex with water is reported to show the existence of two hydrogen bonds. The two hydrogen bonds are formed in the water molecule of two hydrogen-accepting oxygen of carbonyl group of the p-hydroxybenzoic acid. The intermolecular interaction two hydrogen bond of the model system of the water- p-hydroxybenzoic acid was investigated. An experimental study and a theoretical analysis using the B3LYP/6-31G* method in the GAUSSIAN-03 package program were conducted on the three natural products. The theoretical results are supplemented by experimental data. Optimal geometric structures of three compounds were also determined. The calculated molecular mechanics compared quite well with those obtained from the experimental data. The ionization potentials, highest occupied molecular orbital energy, lowest unoccupied molecular orbital energy, energy gaps, heat of formation, atomization energies, and vibration frequencies of the compounds were also calculated. The results of the calculations show that three natural products are stable molecules with high reactive and various other physical properties. The study also provided an explicit understanding of the sterochemical structure and thermodynamic properties of the three natural products.

  5. Palladium-Catalyzed Modification of Unprotected Nucleosides, Nucleotides, and Oligonucleotides

    Directory of Open Access Journals (Sweden)

    Kevin H. Shaughnessy

    2015-05-01

    Full Text Available Synthetic modification of nucleoside structures provides access to molecules of interest as pharmaceuticals, biochemical probes, and models to study diseases. Covalent modification of the purine and pyrimidine bases is an important strategy for the synthesis of these adducts. Palladium-catalyzed cross-coupling is a powerful method to attach groups to the base heterocycles through the formation of new carbon-carbon and carbon-heteroatom bonds. In this review, approaches to palladium-catalyzed modification of unprotected nucleosides, nucleotides, and oligonucleotides are reviewed. Polar reaction media, such as water or polar aprotic solvents, allow reactions to be performed directly on the hydrophilic nucleosides and nucleotides without the need to use protecting groups. Homogeneous aqueous-phase coupling reactions catalyzed by palladium complexes of water-soluble ligands provide a general approach to the synthesis of modified nucleosides, nucleotides, and oligonucleotides.

  6. Graphene oxide catalyzed cis-trans isomerization of azobenzene

    Directory of Open Access Journals (Sweden)

    Dongha Shin

    2014-09-01

    Full Text Available We report the fast cis-trans isomerization of an amine-substituted azobenzene catalyzed by graphene oxide (GO, where the amine functionality facilitates the charge transfer from azobenzene to graphene oxide in contrast to non-substituted azobenzene. This catalytic effect was not observed in stilbene analogues, which strongly supports the existence of different isomerization pathways between azobenzene and stilbene. The graphene oxide catalyzed isomerization is expected to be useful as a new photoisomerization based sensing platform complementary to GO-based fluorescence quenching methods.

  7. New Palladium-Catalyzed Approaches to Heterocycles and Carbocycles

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Qinhua [Iowa State Univ., Ames, IA (United States)

    2004-12-19

    The tert-butylimines of o-(1-alkynyl)benzaldehydes and analogous pyridinecarbaldehydes have been cyclized under very mild reaction conditions in the presence of I2, ICl, PhSeCl, PhSCl and p-O2NC6H4SCl to give the corresponding halogen-, selenium- and sulfur-containing disubstituted isoquinolines and naphthyridines, respectively. Monosubstituted isoquinolines and naphthyridines have been synthesized by the metal-catalyzed ring closure of these same iminoalkynes. This methodology accommodates a variety of iminoalkynes and affords the anticipated heterocycles in moderate to excellent yields. The Pd(II)-catalyzed cyclization of 2-(1-alkynyl)arylaldimines in the presence of various alkenes provides an efficient way to synthesize a variety of 4-(1-alkenyl)-3-arylisoquinolines in moderate to excellent yields. The introduction of an ortho-methoxy group on the arylaldimine promotes the Pd-catalyzed cyclization and stabilizes the resulting Pd(II) intermediate, improving the yields of the isoquinoline products. Highly substituted naphthalenes have been synthesized by the palladium-catalyzed annulation of a variety of internal alkynes, in which two new carbon-carbon bonds are formed in a single step under relatively mild reaction conditions. This method has also been used to synthesize carbazoles, although a higher reaction temperature is necessary. The process involves arylpalladation of the alkyne, followed by intramolecular Heck olefination and double bond isomerization. This method accommodates a variety of functional groups and affords the anticipated highly substituted naphthalenes and carbazoles in good to excellent yields. Novel palladium migratiodarylation methodology for the synthesis of complex fused polycycles has been developed, in which one or more sequential Pd-catalyzed intramolecular migration processes involving C-H activation are employed. The chemistry works best with electron-rich aromatics, which is in agreement

  8. Cyclodextrin-Catalyzed Organic Synthesis: Reactions, Mechanisms, and Applications

    Directory of Open Access Journals (Sweden)

    Chang Cai Bai

    2017-09-01

    Full Text Available Cyclodextrins are well-known macrocyclic oligosaccharides that consist of α-(1,4 linked glucose units and have been widely used as artificial enzymes, chiral separators, chemical sensors, and drug excipients, owing to their hydrophobic and chiral interiors. Due to their remarkable inclusion capabilities with small organic molecules, more recent interests focus on organic reactions catalyzed by cyclodextrins. This contribution outlines the current progress in cyclodextrin-catalyzed organic reactions. Particular emphases are given to the organic reaction mechanisms and their applications. In the end, the future directions of research in this field are proposed.

  9. Recent advances in copper-catalyzed asymmetric coupling reactions

    Directory of Open Access Journals (Sweden)

    Fengtao Zhou

    2015-12-01

    Full Text Available Copper-catalyzed (or -mediated asymmetric coupling reactions have received significant attention over the past few years. Especially the coupling reactions of aryl or alkyl halides with nucleophiles became a very powerful tool for the formation of C–C, C–N, C–O and other carbon–heteroatom bonds as well as for the construction of heteroatom-containing ring systems. This review summarizes the recent progress in copper-catalyzed asymmetric coupling reactions for the formation of C–C and carbon–heteroatom bonds.

  10. Microbial-Catalyzed Biotransformation of Multifunctional Triterpenoids Derived from Phytonutrients

    Directory of Open Access Journals (Sweden)

    Syed Adnan Ali Shah

    2014-07-01

    Full Text Available Microbial-catalyzed biotransformations have considerable potential for the generation of an enormous variety of structurally diversified organic compounds, especially natural products with complex structures like triterpenoids. They offer efficient and economical ways to produce semi-synthetic analogues and novel lead molecules. Microorganisms such as bacteria and fungi could catalyze chemo-, regio- and stereospecific hydroxylations of diverse triterpenoid substrates that are extremely difficult to produce by chemical routes. During recent years, considerable research has been performed on the microbial transformation of bioactive triterpenoids, in order to obtain biologically active molecules with diverse structures features. This article reviews the microbial modifications of tetranortriterpenoids, tetracyclic triterpenoids and pentacyclic triterpenoids.

  11. Silver and gold nanocluster catalyzed reduction of methylene blue ...

    Indian Academy of Sciences (India)

    Abstract. Arsenic can be determined in parts-per-million (ppm) level by absorbance measurement. This method is based on the quantitative colour bleaching of the dye, methylene blue by arsine catalyzed by nanoparticles in micellar medium. The arsine has been generated in situ from sodium arsenate by NaBH4 reduction.

  12. Silver and gold nanocluster catalyzed reduction of methylene blue ...

    Indian Academy of Sciences (India)

    Unknown

    nanoparticles in micellar medium. The arsine has been generated in situ from sodium arsenate ... trolled use of arsenic containing pesticides, paints and pigments etc. Keeping an eye on this grave situation of ... levels using micelle catalyzed reaction (Pal et al 1998). The participation of silver or gold nanoparticle as catalyst.

  13. The 2010 Chemistry Nobel Prize: Pd (0)-Catalyzed Organic Synthesis

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 16; Issue 2. The 2010 Chemistry Nobel Prize: Pd(O)-Catalyzed Organic Synthesis. Gopalpur Nagendrappa Y C Sunil Kumar. General Article Volume 16 Issue 2 February 2011 pp 152-164 ...

  14. Bioepoxidation of isosafrol catalyzed by radish and turnip peroxidases

    African Journals Online (AJOL)

    Peroxidases (PODs) from radish (Raphanus sativus L.) and turnip (Brassica napus L.) were extracted and precipitated with ammonium sulfate using a simple, low cost and quick method. The activities of all steps performed by the vegetable PODs were measured via guaiacol assay. The epoxidation of isosafrol, catalyzed by ...

  15. Transfer hydrogenation reactions catalyzed by chiral half-sandwich ...

    Indian Academy of Sciences (India)

    oxidoreductases catalyze transfer hydrogenation of car- ... ruthenium(II) complexes containing (S)-N-substituted- ... 2. Experimental. 2.1 Materials and methods. All reactions and manipulations were routinely per- formed under a nitrogen atmosphere using standard. Schlenk techniques in oven-dried glassware. L-Proline,.

  16. Development of a Lewis Base Catalyzed Selenocyclization Reaction

    Science.gov (United States)

    Collins, William

    2009-01-01

    The concept of Lewis base activation of selenium Lewis acids has been effectively reduced to practice in the Lewis base catalyzed selenofunctionalization of unactivated olefins. In this reaction, the weakly acidic species, "N"-phenylselenyl succinimide, is cooperatively activated by the addition of a "soft" Lewis base donor (phosphine sulfides,…

  17. CU(II): catalyzed hydrazine reduction of ferric nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Karraker, D.G.

    1981-11-01

    A method is described for producing ferrous nitrate solutions by the cupric ion-catalyzed reduction of ferric nitrate with hydrazine. The reaction is complete in about 1.5 hours at 40/sup 0/C. Hydrazoic acid is also produced in substantial quantities as a reaction byproduct.

  18. Lipase-Catalyzed Modification of Canola Oil with Caprylic Acid

    DEFF Research Database (Denmark)

    Wang, Yingyao; Luan, Xia; Xu, Xuebing

    Lipase-catalyzed acidolysis of canola oil with caprylic acid was performed to produce structured lipids. Six commercial lipases from different sources were screened for their ability to incorporate the caprylic acid into the canola oil. The positional distribution of FA on the glycerol backbone...

  19. Platinum-catalyzed hydroformylation of terminal and internal octenes

    NARCIS (Netherlands)

    van Duren, R.; van der Vlugt, J.I.; Kooijman, H.|info:eu-repo/dai/nl/091208610; Spek, A.L.|info:eu-repo/dai/nl/156517566; Vogt, D.

    2007-01-01

    A brief historic overview of Pt/Sn-catalyzed hydroformylation as well as recent advances in the hydroformylation of internal alkenes is provided. This serves as background for the results obtained with the [Pt(Sixantphos)Cl2] system, for which the molecular structure and the spectroscopic data are

  20. Asymmetric gold-catalyzed lactonizations in water at room temperature**

    Science.gov (United States)

    Handa, Sachin; Lippincott, Daniel J.; Slack, Eric D.; Aue, Donald H.

    2014-01-01

    Asymmetric gold-catalyzed hydrocarboxylations are reported that show broad substrate scope. The hydrophobic effect associated with in situ-formed aqueous nanomicelles leads to good-to-excellent ee’s of product lactones. In-flask product isolation, along with recycling of the catalyst and reaction medium, combine to arrive at an especially environmentally friendly process. PMID:25124085

  1. Catalyzing new product adoption at the base of the pyramid

    NARCIS (Netherlands)

    Marinakis, Yorgos; Walsh, Steven Thomas; Harms, Rainer

    2016-01-01

    One of the more perplexing of the entrepreneurial issues at the Base of the Pyramid (BoP) is how to catalyze new product adoption by BoP consumers. Because S-shaped adoption dynamics are the result of cultural transmission bias, the question can be rephrased as, how can an entrepreneur overcome

  2. Manganese-Catalyzed Aerobic Heterocoupling of Aryl Grignard Reagents

    DEFF Research Database (Denmark)

    Ghaleshahi, Hajar Golshahi; Antonacci, Giuseppe; Madsen, Robert

    2017-01-01

    An improved protocol has been developed for the MnCl2-catalyzed cross-coupling reaction of two arylmagnesium bromides under dioxygen. The reaction was achieved by using the Grignard reagents in a 2:1 ratio and 20 % of MnCl2. Very good yields of the heterocoupling product were obtained when the li...

  3. EFFICIENT SODIUM SELENATE-CATALYZED SYNTHESIS OF 3,4 ...

    African Journals Online (AJOL)

    Sodium selenate efficiently catalyzes the three-component Biginelli reaction of an aldehyde, a,β-keto ester and urea or thiourea under solvent-free conditions to afford the corresponding 3,4-dihydropyrimidin-2(1H)-ones or –thiones in excellent yields. KEY WORDS: Dihydropyrimidinones, Sodium selenate, Biginelli reaction, ...

  4. Base catalyzed transesterification of sunflower oil biodiesel | Ahmad ...

    African Journals Online (AJOL)

    Electric oil expeller was used for the extraction of crude oil. Base catalyzed transesterifiction process is applied for optimum yield (80%) of biodiesel. Fuel properties of sunflower oil biodiesel were compared with American Society for Testing and Materials (ASTM). Engine efficiency of biodiesel with reference to power, ...

  5. Comparison of lipase-catalyzed synthesis of cyclopentadecanolide ...

    African Journals Online (AJOL)

    Administrator

    2011-09-26

    Sep 26, 2011 ... hydroxy-pentadecanate is not. It was reported that, ultra- sonic technology had been widely used in bioreaction system and had achieved ideal results (Du et al., ..... Enantioselective synthesis of silicon- containing(R)-ketone cyanhydrin catalyzed by(R)-oxynitrilase from plum in an aqueous/organic biphasic ...

  6. Palladium-catalyzed selective acyloxylation using sodium perborate as oxidant.

    Science.gov (United States)

    Pilarski, Lukasz T; Janson, Pär G; Szabó, Kálmán J

    2011-03-04

    Sodium perborate (SPB), a principal component of washing powders, was employed as an inexpensive and eco-friendly oxidant in the palladium-catalyzed C-H acyloxylation of alkenes in excellent regio- and stereochemistry. The reactions used anhydrides as acyloxy sources. The method applies to both terminal and internal alkenes, and even benzylic C-H oxidation.

  7. Transition-Metal-Catalyzed Carbonylation of Methyl Acetate.

    Science.gov (United States)

    Polichnowski, S. W.

    1986-01-01

    Presents a study of the rhodium-catalyzed, ioding-promoted carbonylation of methyl acetate. This study provides an interesting contrast between the carbonylation of methyl acetate and the carbonylation of methanol when similar rhodium/iodine catalyst systems are used. (JN)

  8. Recent developments in gold-catalyzed cycloaddition reactions

    Directory of Open Access Journals (Sweden)

    Fernando López

    2011-08-01

    Full Text Available In the last years there have been extraordinary advances in the development of gold-catalyzed cycloaddition processes. In this review we will summarize some of the most remarkable examples, and present the mechanistic rational underlying the transformations.

  9. DNA strand exchange catalyzed by molecular crowding in PEG solutions

    KAUST Repository

    Feng, Bobo

    2010-01-01

    DNA strand exchange is catalyzed by molecular crowding and hydrophobic interactions in concentrated aqueous solutions of polyethylene glycol, a discovery of relevance for understanding the function of recombination enzymes and with potential applications to DNA nanotechnology. © 2010 The Royal Society of Chemistry.

  10. Amylase catalyzed synthesis of glycosyl acrylates and their polymerization

    NARCIS (Netherlands)

    Kloosterman, Wouter M.J.; Jovanovic, Danijela; Brouwer, Sander; Loos, Katja

    2014-01-01

    The enzymatic synthesis of novel (di)saccharide acrylates from starch and 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate and 4-hydroxybutyl acrylate (2-HEA, 2-HEMA and 4-HBA) catalyzed by various commercially available amylase preparations is demonstrated. Both liquefaction and

  11. Synthesis of bifunctional molecules containing [12]aneN3 and coumarin moieties as effective DNA condensation agents and new non-viral gene vectors.

    Science.gov (United States)

    Yue, Pan; Zhang, Ying; Guo, Zhi-Fo; Cao, Ao-Cheng; Lu, Zhong-Lin; Zhai, Yong-Gong

    2015-04-21

    A series of bifunctional molecules with different combinations of macrocyclic polyamine [12]aneN3 and coumarin moieties, 4a/b and 5a/b, were synthesized by a two-step copper(I)-mediated alkyne–azide click reactions between 1,3,5-tris(azidomethyl)benzene and Boc-protected N-propynyl-[12]aneN3/7-propynyloxycoumarins. Agarose gel electrophoresis experiments indicated that bifunctional molecules 4b and 5b effectively induced complete plasmid DNA condensation at concentrations up to 40 μM. It was found that the structural variation had a major impact on the condensation behavior of these compounds. The electrostatic interaction involving the [12]aneN3 moiety can be compensated by the binding contribution of the coumarin units during the DNA condensation process. These two types of interaction showed different effects on the reversibility of DNA condensation. Results from studies using dynamic laser scattering, atomic force microscopy, and EB replacement assay further supported the above conclusion. Cytotoxicity assays on bifunctional compounds 4a/b and 5a/b indicated their low cytotoxicity. Results from cellular uptake and cell transfection experiments proved that bifunctional compounds 4b and 5b successfully served as non-viral gene vectors. Furthermore, methyl substituents attached to the coumarin unit (4b and 5b) greatly enhanced their DNA condensation capability and gene transfection. These bifunctional molecules, with the advantages of lower cytotoxicity, good water solubility, and potential structural modification, will have great potential for the development of new non-viral gene delivery agents.

  12. Larvicidal activity of Cnidium monnieri fruit coumarins and structurally related compounds against insecticide-susceptible and insecticide-resistant Culex pipiens pallens and Aedes aegypti.

    Science.gov (United States)

    Wang, Zhangqian; Kim, Jun-Ran; Wang, Mo; Shu, Shaohua; Ahn, Young-Joon

    2012-07-01

    An assessment was made of the toxicity of imperatorin and osthole identified in Cnidium monnieri fruit, 11 related compounds and five insecticides to larvae from insecticide-susceptible Culex pipiens pallens (KS-CP strain) and Aedes aegypti and wild C.p. pallens (YS-CP colony) using a direct-contact mortality bioassay. Results were compared with those of the conventional larvicide temephos. Imperatorin (LC(50) = 3.14 and 2.88 mg L(-1) ) was 1.9-, 3.7- and 4.2-fold and 2.4-, 4.5- and 4.6-fold more toxic than isopimpinellin, isoimperatorin and osthole against susceptible C. p. pallens and A. aegypti larvae respectively. Overall, all of the compounds were less toxic than temephos (0.011 and 0.019 mg L(-1) ). The toxicity of these compounds was virtually identical against larvae from the two Culex strains, even though YS-CP larvae were resistant to fenthion (resistance ratio RR = 390), deltamethrin (RR = 164), cyfluthrin (RR = 14) and temephos (RR = 14). This finding indicates that the coumarins and the insecticides do not share a common mode of action. The structure-activity relationship indicates that the chemical structure and alkoxy substitution and length of the alkoxyl side chain at the C8 position are essential for imparting toxicity. The C. monnieri fruit-derived coumarins and the related coumarins described merit further study as potential insecticides or lead molecules for the control of insecticide-resistant mosquito populations. Copyright © 2012 Society of Chemical Industry.

  13. Theoretical Studies on Two-Photon Fluorescent Hg2+ Probes Based on the Coumarin-Rhodamine System

    Directory of Open Access Journals (Sweden)

    Yujin Zhang

    2017-07-01

    Full Text Available The development of fluorescent sensors for Hg2+ has attracted much attention due to the well-known adverse effects of mercury on biological health. In the present work, the optical properties of two newly-synthesized Hg2+ chemosensors based on the coumarin-rhodamine system (named Pro1 and Pro2 were systematically investigated using time-dependent density functional theory. It is shown that Pro1 and Pro2 are effective ratiometric fluorescent Hg2+ probes, which recognize Hg2+ by Förster resonance energy transfer and through bond energy transfer mechanisms, respectively. To further understand the mechanisms of the two probes, we have developed an approach to predict the energy transfer rate between the donor and acceptor. Using this approach, it can be inferred that Pro1 has a six times higher energy transfer rate than Pro2. Thus the influence of spacer group between the donor and acceptor on the sensing performance of the probe is demonstrated. Specifically, two-photon absorption properties of these two probes are calculated. We have found that both probes show significant two-photon responses in the near-infrared light region. However, only the maximum two-photon absorption cross section of Pro1 is greatly enhanced with the presence of Hg2+, indicating that Pro1 can act as a potential two-photon excited fluorescent probe for Hg2+. The theoretical investigations would be helpful to build a relationship between the structure and the optical properties of the probes, providing information on the design of efficient two-photon fluorescent sensors that can be used for biological imaging of Hg2+ in vivo.

  14. Highly selective on-off fluorescence recognition of Fe3+ based on a coumarin derivative and its application in live-cell imaging

    Science.gov (United States)

    Warrier, Sona; Kharkar, Prashant S.

    2018-01-01

    A novel coumarin chemosensor, 7-hydroxy-2-oxo-N-(pyridin-2-ylmethyl)chromene-3-carboxamide (Probe 1), demonstrated significant selectivity towards Fe3+ ions. Probe 1 exhibited high fluorescence emission profile at 447 nm, excellent selectivity towards Fe3+ over other biologically important metal ions (Al3+, Ba2+, Co2+, Cu2+, Zn2+, Cd2+, Hg2+, Pb2+ and Sn2+). Interestingly, there was 30-fold decrease in fluorescence intensity upon Fe3+ binding. The limit of detection of Fe3+ was found to be 0.76 μM ( 40 ppb). Probe 1 also exhibited high potential as an intracellular chemosensor for Fe3+.

  15. Intermolecular electron transfer between coumarin dyes and aromatic amines in Triton-X-100 micellar solutions: Evidence for Marcus inverted region

    Science.gov (United States)

    Kumbhakar, Manoj; Nath, Sukhendu; Mukherjee, Tulsi; Pal, Haridas

    2004-02-01

    Photoinduced electron transfer (ET) between coumarin dyes and aromatic amines has been investigated in Triton-X-100 micellar solutions and the results have been compared with those observed earlier in homogeneous medium. Significant static quenching of the coumarin fluorescence due to the presence of high concentration of amines around the coumarin fluorophore in the micelles has been observed in steady-state fluorescence studies. Time-resolved studies with nanosecond resolutions mostly show the dynamic part of the quenching for the excited coumarin dyes by the amine quenchers. A correlation of the quenching rate constants, estimated from the time-resolved measurements, with the free energy changes (ΔG0) of the ET reactions shows the typical bell shaped curve as predicted by Marcus outer-sphere ET theory. The inversion in the ET rates for the present systems occurs at an exergonicity (-ΔG0) of ~0.7-0.8 eV, which is unusually low considering the polarity of the Palisade layer of the micelles where the reactants reside. Present results have been rationalized on the basis of the two dimensional ET model assuming that the solvent relaxation in micellar media is much slower than the rate of the ET process. Detailed analysis of the experimental data shows that the diffusional model of the bimolecular quenching kinetics is not applicable for the ET reactions in the micellar solutions. In the present systems, the reactions can be better visualized as equivalent to intramolecular electron transfer processes, with statistical distribution of the donors and acceptors in the micelles. A low electron coupling (Vel) parameter is estimated from the correlation of the experimentally observed and the theoretically calculated ET rates, which indicates that the average donor-acceptor separation in the micellar ET reactions is substantially larger than for the donor-acceptor contact distance. Comparison of the Vel values in the micellar solution and in the donor-acceptor close

  16. NTP Toxicology and Carcinogenesis Studies of Coumarin (CAS No. 91-64-5) in F344/N Rats and B6C3F1 Mice (Gavage Studies).

    Science.gov (United States)

    1993-09-01

    Coumarin is the basic structure of numerous naturally occurring compounds with important and diverse physiological activities. More than a thousand coumarin derivatives have been described, varying from simple coumarins containing alkyl and hydroxyl side chains to complex coumarins with benzoyl, furanoyl, pyranoyl, or alkylphosphorothionyl substituents. Coumarin and 3,4-dihydrocoumarin were nominated by the Food and Drug Administration and the National Cancer Institute for study because of the widespread use of coumarin in perfumes, cosmetics, and other products as a fragrance, continued interest in coumarin compounds as flavor-enhancing agents for foods, and the interest in structure-activity relationships of this important group of compounds. Coumarin is believed to be metabolized to a 3,4-epoxide intermediate, which may be responsible for its toxic effects, while 3,4-dihydrocoumarin, which lacks the 3,4-double bond, is not considered likely to form an epoxide intermediate. Toxicity and carcinogenicity studies were conducted by administering coumarin (97% pure) in corn oil by gavage to groups of male and female F344/N rats and B6C3F1 mice for 16 days, 13 weeks, and 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, cultured Chinese hamster ovary cells, Drosophila melanogaster, and B6C3F1 mice. 16-DAY STUDY IN RATS: Groups of five male and five female rats received coumarin in corn oil by gavage at doses of 0, 25, 50, 100, 200, or 400 mg per kg body weight, 5 days a week for a total of 12 doses in a 16-day period. All female rats and four male rats receiving 400 mg/kg died. The mean body weight gains and final mean body weights of surviving dosed male and female rats were similar to those of the controls. There were no clinical signs of organ-specific toxicity, and there was no evidence of impaired blood coagulation from measurements of capillary clotting time or prothrombin and activated partial thromboplastin time. 16-DAY STUDY IN MICE

  17. Coumarin or benzoxazinone bearing benzimidazolium and bis(benzimidazolium salts; involvement in transfer hydrogenation of acetophenone derivatives and hCA inhibition

    Directory of Open Access Journals (Sweden)

    Mert Olgun Karataş

    2015-10-01

    Full Text Available Four new salts of benzimidazolium and bis(benzimidazolium which include coumarin or benzoxazinone moieties were synthesized and the structures of the newly synthesized compounds were elucidated on the basis of spectral analyses such as 1H-NMR, 13C-NMR, HSQC, IR, LC-MS and elemental analysis. Benzimidazolium salts were used intensively as N-heterocyclic carbene (NHC precursors in the various catalytic reactions such as transfer hydrogenation (TH, C-H bond activation, Heck, Suzuki reaction etc. With the prospect of potential NHC precursor properties of the synthesized compounds, they were employed in the (TH reaction of p-substitute acetophenones (acetophenone, p-methyl acetophenone, p-chloro acetophenone and good yields were observed. Coumarin compounds are known as inhibitor of carbonic anhydrase and inhibition effects of the synthesized compounds on human carbonic anhydrases (hCA were investigated as in vitro. The in vitro results demonstrated that all compounds inhibited hCA I and hCA II activity. Among the synthesized compounds 1,4-bis(1-((6,8-dimethyl-2H-chromen-2-one-4-ylmethylbenzimidazolium-3-ylbutane dichloride was found to be the most active IC50= 5.55 mM and 6.06 mM for hCA I and hCA II, respectively.

  18. Visualization of Fluoride Ions In Vivo Using a Gadolinium(III-Coumarin Complex-Based Fluorescence/MRI Dual-Modal Probe

    Directory of Open Access Journals (Sweden)

    Yue Wang

    2016-12-01

    Full Text Available A new Gadolinium(III–coumarin complex, DO3A-Gd-CA, was designed and prepared as a dual-modal probe for simultaneous fluorescence and relaxivity responses to fluoride ions (F− in aqueous media and mice. DO3A-Gd-CA was designed by using Gd(III center as an MRI signal output unit and fluoride binding site, and the 4-(diethylamino-coumarin-3-carboxylic acid (CA as a fluorescence reporter. Upon the addition of fluoride ions to the solution of DO3A-Gd-CA, the liberation of the coordinated CA ligand led to a 5.7-fold fluorescence enhancement and a 75% increase in the longitudinal relaxivity (r1. The fluorescent detection limit for fluoride ions was determined to be 8 μM based on a 3σ/slope. The desirable features of the proposed DO3A-Gd-CA, such as high sensitivity and specificity, reliability at physiological pH and low cytotoxicity enable its application in visualization of fluoride ion in mice. The successful in vivo imaging indicates that DO3A-Gd-CA could be potentially used in biomedical diagnosis fields.

  19. [Effects of total coumarins, essential oil and water extracts of Cnidium monnieri on plasma prostaglandin and cyclic nucleotide in the rats of kidney-yang insufficiency].

    Science.gov (United States)

    Qin, L P; Wu, H; Zhou, Q H

    1993-02-01

    Effects of total coumarins, essential oil and water extracts of Cnidium monnieri on plasma prostaglandin (PGE2 and PGF2 alpha) and cyclic nucleotide levels in rats of Kidney-Yang insufficiency were studied. 55 rats were divided randomly into 5 groups, Group I was administered orally with saline (normal group), group II was injected with intraperitonally hydrocortison acetate to induce Kidney-Yang insufficiency (control group), group III, group IV and group V (experimental groups) were injected with hydrocortison acetate, the same as group II, and administered orally with the total coumarins, essential oil and water extracts of Fructus Cnidii respectively. The levels of plasma PGE2, PG2 alpha and plasma cAMP, cGMP were measured. In group II, in comparing with those of group I, the levels of plasma PGE2, and PGF2 alpha decreased significantly (P Cnidium monnieri are probably the effective ingredients to invigorate Kidney and strengthen Yang, while the efficacy of essential oil remained unconfirmed.

  20. Anti-tumour activity of a novel coumarin-chalcone hybrid is mediated through intrinsic apoptotic pathway by inducing PUMA and altering Bax/Bcl-2 ratio.

    Science.gov (United States)

    Singh, Neetu; Sarkar, Jayanta; Sashidhara, Koneni V; Ali, Shakir; Sinha, Sudhir

    2014-06-01

    Coumarins and chalcones are secondary plant metabolites which have shown an array of pharmacological properties including anti-tumour activity. We have previously reported on the synthesis and anti-proliferative activity of a series of novel coumarin-chalcone hybrids. Now we report on the in vivo efficacy as well as mechanism of action of the most potent molecule of the series, S009-131. Oral administration of this molecule resulted in regression of tumours induced by HeLa cell xenografts in nod SCID mice. The molecule inhibited proliferation of cervical cancer cells (HeLa and C33A) by inducing apoptosis and arresting cell cycle at G2/M phase. Apoptosis was induced through induction of caspase-dependent intrinsic pathway and alterations in the cellular levels of Bcl-2 family proteins. The mitochondrial transmembrane potential got highly depleted in S009-131 treated cells due to an increase in Bax/Bcl-2 ratio and intracellular ROS. The molecule induced release of cytochrome c into the cytosol and activation of initiator caspase-9 and executioner caspases-3/7. Tumour suppressor protein p53 and its transcriptional target PUMA were up regulated, suggesting their role in mediating the cell death. These results suggest that S009-131 is a potent candidate for the chemotherapy of cervical carcinoma.

  1. Comparative Evaluation of Cytotoxic and Apoptogenic Effects of Several Coumarins on Human Cancer Cell Lines: Osthole Induces Apoptosis in p53-Deficient H1299 Cells

    Directory of Open Access Journals (Sweden)

    Yalda Shokoohinia

    2014-01-01

    Full Text Available Natural products are excellent resources for finding lead structures for the development of chemotherapeutic agents. Coumarins are a class of natural compounds found in a variety of plants. In this study, we evaluated the cytotoxic potential of coumarins isolated from Prangos ferulacea (L. Lindl. in PC3, SKNMC, and H1299 (p53 null human carcinoma cell lines. Osthole proved to be an outstanding potent cytotoxic agent especially against PC3 cells. Isoimperatorin exhibited moderate inhibitory effect against SKNMC and PC3 cell lines. Oxypeucedanin and braylin did not display any cytotoxic activity. In the next set of experiments, the apoptotic potentials of osthole and isoimperatorin were investigated. Induction of apoptosis by isoimperatorin was accompanied by an increase in activation of caspase-3, -8, and -9 in SKNMC cells and caspase-3 and -9 in PC3 cells. Moreover, isoimperatorin induced apoptosis by upregulating Bax and Smac/DIABLO genes in PC3 and SKNMC cells. Osthole induced apoptosis by downregulating antiapoptotic Bcl-2 in only PC3 cells and upregulating the proapoptotic genes Bax and Smac/DIABLO in PC3, SKNMC, and H1299 cells. The effects of osthole on H1299 cells are important because the loss of p53 has been associated with poor clinical prognosis in cancer treatment.

  2. Inhibitory effects of coumarins from the stem barks of Fraxinus rhynchophylla on adipocyte differentiation in 3T3-L1 cells.

    Science.gov (United States)

    Shin, Eunjin; Choi, Kyeong-Mi; Yoo, Hwan-Soo; Lee, Chong-Kil; Hwang, Bang Yeon; Lee, Mi Kyeong

    2010-01-01

    In the course of screening anti-adipogenic activity of natural products employing the preadipocyte cell line, 3T3-L1 as an in vitro assay system, the EtOAc fraction of the stem barks of Fraxinus rhynchophylla DENCE (Oleaceae) showed significant inhibitory activity on adipocyte differentiation as assessed by measuring fat accumulation using Oil Red O staining. Activity-guided fractionation led to the isolation of six coumarins such as esculetin (1), scopoletin (2), fraxetin (3), fraxidin (4) esculin (5) and fraxin (6). Among the six coumarins isolated, esculetin (1) showed the most potent inhibitory activity on adipocyte differentiation, followed by fraxetin (3). Further studies with interval treatment demonstrated that esculetin (1) exerted inhibitory activity on adipocyte differentiation when treated within 2 d (days 0-2) after differentiation induction. We further investigated the effect of esculetin (1) on peroxisome proliferator activated receptor gamma (PPARgamma), one of the early adipogenic transcription factors. Esculetin (1) significantly blocked the induction of PPARgamma protein expression and inhibited adipocyte differentiation induced by troglitazone, a PPARgamma agonist. Taken together, these results suggest that esculetin (1), an active compound from F. rhynchophylla, inhibited early stage of adipogenic differentiation, in part, via inhibition of PPARgamma-dependent pathway.

  3. Mechanism of Intramolecular Rhodium- and Palladium-Catalyzed Alkene Alkoxyfunctionalizations

    KAUST Repository

    Vummaleti, Sai V. C.

    2015-11-13

    Density functional theory calculations have been used to investigate the reaction mechanism for the [Rh]-catalyzed intramolecular alkoxyacylation ([Rh] = [RhI(dppp)+] (dppp, 1,3-bis(diphenylphosphino)propane) and [Pd]/BPh3 dual catalytic system assisted intramolecular alkoxycyanation ([Pd] = Pd-Xantphos) using acylated and cyanated 2-allylphenol derivatives as substrates, respectively. Our results substantially confirm the proposed mechanism for both [Rh]- and [Pd]/ BPh3-mediated alkoxyfunctionalizations, offering a detailed geometrical and energetical understanding of all the elementary steps. Furthermore, for the [Rh]-mediated alkoxyacylation, our observations support the hypothesis that the quinoline group of the substrate is crucial to stabilize the acyl metal complex and prevent further decarbonylation. For [Pd]/BPh3-catalyzed alkoxycyanation, our findings clarify how the Lewis acid BPh3 cocatalyst accelerates the only slow step of the reaction, corresponding to the oxidative addition of the cyanate O-CN bond to the Pd center. © 2015 American Chemical Society.

  4. DNA Self-assembly Catalyzed by Artificial Agents.

    Science.gov (United States)

    Shi, Chao; Wang, Yifan; Zhang, Menghua; Ma, Cuiping

    2017-07-28

    Nucleic acids have been shown to be versatile molecules and engineered to produce various nanostructures. However, the poor rate of these uncatalyzed nucleic acid reactions has restricted the development and applications. Herein, we reported a novel finding that DNA self-assembly could be nonenzymatically catalyzed by artificial agents with an increasing dissociation rate constant K2. The catalytic role of several artificial agents in DNA self-assembly was verified by real-time fluorescent detection or agarose gel electrophoresis. We found that 20% PEG 200 could significantly catalyze DNA self-assembly and increase the reaction efficiency, such as linear hybridization chain reaction (HCR) and exponential hairpin assembly (EHA). Therefore, we foresee that a fast and efficient DNA self-assembly in structural DNA nanotechnology will be desirable.

  5. Mild and efficient cyanuric chloride catalyzed Pictet–Spengler reaction

    Directory of Open Access Journals (Sweden)

    Ashish Sharma

    2013-06-01

    Full Text Available A practical, mild and efficient protocol for the Pictet–Spengler reaction catalyzed by cyanuric chloride (trichloro-1,3,5-triazine, TCT is described. The 6-endo cyclization of tryptophan/tryptamine and modified Pictet–Spengler substrates with both electron-withdrawing and electron-donating aldehydes was carried out by using a catalytic amount of TCT (10 mol % in DMSO under a nitrogen atmosphere. TCT catalyzed the Pictet–Spengler reaction involving electron-donating aldehydes in excellent yield. Thus, it has a distinct advantage over the existing methodologies where electron-donating aldehydes failed to undergo 6-endo cyclization. Our methodology provided broad substrate scope and diversity. This is indeed the first report of the use of TCT as a catalyst for the Pictet–Spengler reaction.

  6. Copper-Catalyzed Alkoxycarbonylation of Alkanes with Alcohols.

    Science.gov (United States)

    Li, Yahui; Wang, Changsheng; Zhu, Fengxiang; Wang, Zechao; Dixneuf, Pierre H; Wu, Xiao-Feng

    2017-04-10

    Esters are important chemicals widely used in various areas, and alkoxycarbonylation represents one of the most powerful tools for their synthesis. In this communication, a new copper-catalyzed carbonylative procedure for the synthesis of aliphatic esters from cycloalkanes and alcohols was developed. Through direct activation of the Csp3 -H bond of alkanes and with alcohols as the nucleophiles, the desired esters were prepared in moderate-to-good yields. Paraformaldehyde could also be applied for in situ alcohol generation by radical trapping, and moderate yields of the corresponding esters could be produced. Notably, this is the first report on copper-catalyzed alkoxycarbonylation of alkanes. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Hydroperoxide-dependent sulfoxidation catalyzed by soybean microsomes.

    Science.gov (United States)

    Blee, E; Durst, F

    1987-04-01

    The sulfoxidation of methiocarb, an aromatic-alkyl sulfide pesticide, catalyzed by soybean microsomes was found to be strongly stimulated in the presence of cumene and linoleic acid hydroperoxides. We have shown that this S-oxidation, which does not require cofactors such as NAD(P)H, is an hydroperoxide-dependent reaction: 18O2-labeling experiments demonstrated that the oxygen atom incorporated into the sulfoxide originated from hydroperoxides rather than from molecular oxygen. In the absence of exogenous hydroperoxides, soybean microsomes catalyzed methiocarb sulfoxide formation at a basal rate dependent on their endogenous hydroperoxides, especially those derived from free fatty acids. The nature of the sulfoxidase is discussed. Our results seem to rule out the participation of cytochrome P-450 in this oxidation, whereas the studied sulfoxidase presents some similarities to plant peroxygenase.

  8. Transition Metal Catalyzed Synthesis of Carboxylic Acids, Imines, and Biaryls

    DEFF Research Database (Denmark)

    Santilli, Carola; Madsen, Robert

    Dehydrogenative synthesis of carboxylic acids catalyzed by a ruthenium N- heterocycliccarbene complex. A new methodology for the synthesis of carboxylic acids from primary alcohols and hydroxide has been developed. The reaction is catalyzed by the ruthenium N-heterocycliccarbene complex [RuCl2(Ii......Pr)(p-cymene)] where dihydrogen is generated as the only by-product (Scheme i). The dehydrogenative reaction is performed in toluene, which allows for a simple isolation of the products by precipitation followed by extraction. Various substituted benzyl alcohols smoothly undergo the transformation. The fast conversion...... to the carboxylic acids can be explained by the involvement of a competing Cannizzaro reaction. The scope of the dehydrogenation was further extended to linear and branched saturated aliphatic alcohols, although longer reaction times are necessary to ensure complete substrate conversions. The kinetic isotope effect...

  9. Identification of the enzymes catalyzing metabolism of methoxyflurane.

    Science.gov (United States)

    Waskell, L; Canova-Davis, E; Philpot, R; Parandoush, Z; Chiang, J Y

    1986-01-01

    The hepatic microsomal metabolism of methoxyflurane in rabbits is markedly stimulated by treatment with phenobarbital. However, the increased rate of metabolism cannot be completely accounted for by the activity of the purified phenobarbital-inducible cytochrome P-450 isozyme 2, even in the presence of cytochrome b5. The discovery of a second hepatic phenobarbital-inducible cytochrome P-450, isozyme 5, led us to undertake experiments to determine in hepatic and pulmonary preparations the portion of microsomal metabolism of methoxyflurane catalyzed by cytochrome P-450 isozymes 2 and 5. We report herein that isozyme 2 accounts for 25% and 29%, respectively, of the O-demethylation of methoxyflurane in hepatic microsomes from untreated and phenobarbital-treated rabbits, and for 25% of the methoxyflurane metabolism in pulmonary microsomes. Results for isozyme 5 indicate that it catalyzes 19% and 27% of methoxyflurane metabolism in control and phenobarbital-induced liver, and 47% of O-demethylation in the lung. In summary, we demonstrate that methoxyflurane O-demethylation in lung, phenobarbital-induced liver, and control liver microsomes is catalyzed by cytochrome P-450 isozymes 2 and 5. Results with purified cytochrome P-450 isozyme 5 are consistent with those obtained using microsomal preparations. Furthermore, metabolism of methoxyflurane by purified isozyme 5 is markedly stimulated by cytochrome b5. A role for cytochrome b5 in cytochrome P-450 isozyme 5-catalyzed metabolism of methoxyflurane was also demonstrated in microsomes. Antibody to isozyme 5 was unable to inhibit methoxyflurane metabolism in the presence of maximally inhibiting concentrations of cytochrome b5 antibody.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. Lipase-Catalyzed Kinetic Resolution of Aryltrimethylsilyl Chiral Alcohols

    Directory of Open Access Journals (Sweden)

    Leandro H. Andrade

    2011-11-01

    Full Text Available Lipase-catalyzed kinetic resolution of aryltrimethylsilyl chiral alcohols through a transesterification reaction was studied. The optimal conditions found for the kinetic resolution of m- and p-aryltrimethylsilyl chiral alcohols, led to excellent results, high conversions (c = 50%, high enantiomeric ratios (E > 200 and enantiomeric excesses for the remaining (S-alcohol and (R-acetylated product (>99%. However, kinetic resolution of o-aryltrimethylsilyl chiral alcohols did not occur under the same conditions applied to the other isomers.

  11. Polyoxometalate catalyzed ozonation of chemical pulps in organic solvent media

    OpenAIRE

    Shatalov, Anatoly A.; Pereira, Helena

    2009-01-01

    Polyoxometalate (POM) catalyzed ozonation of chemical pulps in organic solvent media was found to be particularly effective and selective environmentally benign bleaching approach providing a way for substantial increase in pulp brightness, viscosity and degree of delignification in comparison with other ozone-based bleaching techniques. A series of tested low-boiling polar aprotic and protic organic solvents showed awell-defined capacity for ozonation improvement in the presence ...

  12. Medium effect on cyclohexene hydrocarbomethoxylation catalyzed by ruthenium (III) chloride

    OpenAIRE

    Sevostyanova N.; Batashev S.

    2016-01-01

    This paper presents influence of some solvents on cyclohexene hydrocarbomethoxylation catalyzed by ruthenium(III) chloride. The objective of the work was contained in the determination of medium influence on the reaction rate and yield of product — methyl cyclohexanecarboxylate. The kinetic method was used as the main method of investigation. The gas–liquid chromatography method was used to analyze the reaction mass. Influence of methanol, toluene, acetone and water on the hydrocarmothoxy...

  13. Synthesis of Graphite Encapsulated Metal Nanoparticles and Metal Catalyzed Nanotubes

    Science.gov (United States)

    vanderWal, R. L.; Dravid, V. P.

    1999-01-01

    This work focuses on the growth and inception of graphite encapsulated metal nanoparticles and metal catalyzed nanotubes using combustion chemistry. Deciphering the inception and growth mechanism(s) for these unique nanostructures is essential for purposeful synthesis. Detailed knowledge of these mechanism(s) may yield insights into alternative synthesis pathways or provide data on unfavorable conditions. Production of these materials is highly desirable given many promising technological applications.

  14. Gold-catalyzed cyclization of allenyl acetal derivatives

    Directory of Open Access Journals (Sweden)

    Dhananjayan Vasu

    2013-08-01

    Full Text Available The gold-catalyzed transformation of allenyl acetals into 5-alkylidenecyclopent-2-en-1-ones is described. The outcome of our deuterium labeling experiments supports a 1,4-hydride shift of the resulting allyl cationic intermediates because a complete deuterium transfer is observed. We tested the reaction on various acetal substrates bearing a propargyl acetate, giving 4-methoxy-5-alkylidenecyclopent-2-en-1-ones 4 via a degradation of the acetate group at the allyl cation intermediate.

  15. Vanadium haloperoxidase-catalyzed bromination and cyclization of terpenes.

    Science.gov (United States)

    Carter-Franklin, Jayme N; Parrish, Jon D; Tschirret-Guth, Richard A; Little, R Daniel; Butler, Alison

    2003-04-02

    Marine red algae (Rhodophyta) are a rich source of bioactive halogenated natural products, including cyclic terpenes. The biogenesis of certain cyclic halogenated marine natural products is thought to involve marine haloperoxidase enzymes. Evidence is presented that vanadium bromoperoxidase (V-BrPO) isolated and cloned from marine red algae that produce halogenated compounds (e.g., Plocamium cartilagineum, Laurencia pacifica, Corallina officinalis) can catalyze the bromination and cyclization of terpenes and terpene analogues. The V-BrPO-catalyzed reaction with the monoterpene nerol in the presence of bromide ion and hydrogen peroxide produces a monobromo eight-membered cyclic ether similar to laurencin, a brominated C15 acetogenin, from Laurencia glandulifera, along with noncyclic bromohydrin, epoxide, and dibromoproducts; however, reaction of aqueous bromine with nerol produced only noncyclic bromohydrin, epoxide, and dibromoproducts. The V-BrPO-catalyzed reaction with geraniol in the presence of bromide ion and hydrogen peroxide produces two singly brominated six-membered cyclic products, analogous to the ring structures of alpha and beta snyderols, brominated sesquiterpenes from Laurencia, spp., along with noncyclic bromohydrin, epoxide, and dibromoproducts; again, reaction of geraniol with aqueous bromine produces only noncyclic bromohydrin, epoxide, and dibromoproducts. Thus, V-BrPO can direct the electrophilic bromination and cyclization of terpenes.

  16. Aluminum-catalyzed silicon nanowires: Growth methods, properties, and applications

    Energy Technology Data Exchange (ETDEWEB)

    Hainey, Mel F.; Redwing, Joan M. [Department of Materials Science and Engineering, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

    2016-12-15

    Metal-mediated vapor-liquid-solid (VLS) growth is a promising approach for the fabrication of silicon nanowires, although residual metal incorporation into the nanowires during growth can adversely impact electronic properties particularly when metals such as gold and copper are utilized. Aluminum, which acts as a shallow acceptor in silicon, is therefore of significant interest for the growth of p-type silicon nanowires but has presented challenges due to its propensity for oxidation. This paper summarizes the key aspects of aluminum-catalyzed nanowire growth along with wire properties and device results. In the first section, aluminum-catalyzed nanowire growth is discussed with a specific emphasis on methods to mitigate aluminum oxide formation. Next, the influence of growth parameters such as growth temperature, precursor partial pressure, and hydrogen partial pressure on nanowire morphology is discussed, followed by a brief review of the growth of templated and patterned arrays of nanowires. Aluminum incorporation into the nanowires is then discussed in detail, including measurements of the aluminum concentration within wires using atom probe tomography and assessment of electrical properties by four point resistance measurements. Finally, the use of aluminum-catalyzed VLS growth for device fabrication is reviewed including results on single-wire radial p-n junction solar cells and planar solar cells fabricated with nanowire/nanopyramid texturing.

  17. Aluminum-catalyzed silicon nanowires: Growth methods, properties, and applications

    Science.gov (United States)

    Hainey, Mel F.; Redwing, Joan M.

    2016-12-01

    Metal-mediated vapor-liquid-solid (VLS) growth is a promising approach for the fabrication of silicon nanowires, although residual metal incorporation into the nanowires during growth can adversely impact electronic properties particularly when metals such as gold and copper are utilized. Aluminum, which acts as a shallow acceptor in silicon, is therefore of significant interest for the growth of p-type silicon nanowires but has presented challenges due to its propensity for oxidation. This paper summarizes the key aspects of aluminum-catalyzed nanowire growth along with wire properties and device results. In the first section, aluminum-catalyzed nanowire growth is discussed with a specific emphasis on methods to mitigate aluminum oxide formation. Next, the influence of growth parameters such as growth temperature, precursor partial pressure, and hydrogen partial pressure on nanowire morphology is discussed, followed by a brief review of the growth of templated and patterned arrays of nanowires. Aluminum incorporation into the nanowires is then discussed in detail, including measurements of the aluminum concentration within wires using atom probe tomography and assessment of electrical properties by four point resistance measurements. Finally, the use of aluminum-catalyzed VLS growth for device fabrication is reviewed including results on single-wire radial p-n junction solar cells and planar solar cells fabricated with nanowire/nanopyramid texturing.

  18. Asymmetric Stetter reactions catalyzed by thiamine diphosphate-dependent enzymes.

    Science.gov (United States)

    Kasparyan, Elena; Richter, Michael; Dresen, Carola; Walter, Lydia S; Fuchs, Georg; Leeper, Finian J; Wacker, Tobias; Andrade, Susana L A; Kolter, Geraldine; Pohl, Martina; Müller, Michael

    2014-12-01

    The intermolecular asymmetric Stetter reaction is an almost unexplored transformation for biocatalysts. Previously reported thiamine diphosphate (ThDP)-dependent PigD from Serratia marcescens is the first enzyme identified to catalyze the Stetter reaction of α,β-unsaturated ketones (Michael acceptor substrates) and α-keto acids. PigD is involved in the biosynthesis of the potent cytotoxic agent prodigiosin. Here, we describe the investigation of two new ThDP-dependent enzymes, SeAAS from Saccharopolyspora erythraea and HapD from Hahella chejuensis. Both show a high degree of homology to the amino acid sequence of PigD (39 and 51 %, respectively). The new enzymes were heterologously overproduced in Escherichia coli, and the yield of soluble protein was enhanced by co-expression of the chaperone genes groEL/ES. SeAAS and HapD catalyze intermolecular Stetter reactions in vitro with high enantioselectivity. The enzymes possess a characteristic substrate range with respect to Michael acceptor substrates. This provides support for a new type of ThDP-dependent enzymatic activity, which is abundant in various species and not restricted to prodigiosin biosynthesis in different strains. Moreover, PigD, SeAAS, and HapD are also able to catalyze asymmetric carbon-carbon bond formation reactions of aldehydes and α-keto acids, resulting in 2-hydroxy ketones.

  19. Incremental cost-effectiveness of cyclooxygenase 2-selective versus nonselective nonsteroidal anti-inflammatory drugs in a cohort of coumarin users: a pharmacoeconomic analysis linked to a case-control study.

    NARCIS (Netherlands)

    Knijff-Dutmer, Ellen A.J.; Postma, Maarten J.; van der Palen, Jacobus Adrianus Maria; van der Palen, J.; Brouwers, Jacobus R.B.J.; van de Laar, Mart A F J

    2004-01-01

    Background: A previous case-control study involving concomitant users of coumarin and nonsteroidal anti-inflammatory drugs (NSAIDs) found that cyclooxygenase 2 (COX-2)-selective NSAIDs were associated with fewer bleeding complications than nonselective NSAIDs. Objective: The goal of this study was

  20. On-line concentration by field-enhanced sample injection with reverse migrating micelles in micellar electrokinetic capillary chromatography for the analysis of coumarins from traditional Chinese medicine and human serum.

    Science.gov (United States)

    Jiang, Ting-Fu; Lv, Zhi-Hua; Wang, Yuan-Hong; Yue, Mei-E

    2010-06-01

    In this work, a simple, reproducible and sensitive micellar electrokinetic chromatography method was developed for the separation and determination of three coumarins, imperatorin (IM), isoimperatorin (IO) and osthole (OS) from traditional Chinese medicine and human serum. Field-enhanced sample injection with reverse migrating micelles was used for on-line concentration of the coumarins. The optimum buffer contained 50 mM H(3)PO(4), 160 mM sodium dodecyl sulfate, 20% acetonitrile and 15% 2-propanol, and the pH of buffer was 2.0. The sample solution was diluted with water containing 5 mM sodium dodecyl sulfate and injected for 15 s with -8 kV after injection of 2 s water plug. The effects of concentrations of sodium dodecyl sulfate and organic modifier, the sample matrix, the injection time of water plug, the injection voltage and injection time of sample on the separation and stacking efficiency were investigated. Under the optimum conditions, the analytes were well separated and by optimizing the stacking conditions, about 93, 195 and 136 fold improvement in the detection sensitivity was obtained for IM, IO and OS. The contents of three coumarins in Angelica dahurica Benth, Radix Angelicae Pubescentis and Fructus Cnidii were successfully determined with satisfactory repeatability and recovery. The possibilities of using this method for the determination of three coumarins in spiked human serum were also tested. Copyright 2009 John Wiley & Sons, Ltd.

  1. Simultaneous determination of aegeline and six coumarins from different parts of the plant Aegle marmelos using UHPLC-PDA-MS and chiral separation of aegeline using HPLC-ToF-MS

    Science.gov (United States)

    A fast UHPLC-PDA method was developed for the simultaneous analysis of one alkaloid, aegeline, and six coumarins namely: umbelliferone; scopoletin; marmesinin; 8-hydroxypsoralen angelicin and marmelosin from leaf, fruit, root and bark of Aegle marmelos (L.) Corrêa (Rutaceae). The method was validate...

  2. Mechanism of the reaction catalyzed by mandelate racemase. 3. Asymmetry in reactions catalyzed by the H297N mutant

    Energy Technology Data Exchange (ETDEWEB)

    Landro, J.A.; Kallarakal, A.T.; Ransom, S.C.; Gerlt, J.A.; Kozarich, J.W. (Univ. of Maryland, College Park (United States)); Neidhart, D.J. (Abbott Labs., Abbott Park, IL (United States)); Kenyon, G.L. (Univ. of California, San Francisco (United States))

    1991-09-24

    Two preceding papers suggest that the active site of mandelate racemase (MR) contains two distinct general acid/base catalysts: Lys 166, which abstracts the {alpha}-proton from (s)-mandelate, and His 297, which abstracts the {alpha}-proton from (R)-mandelate. In this paper the authors report on the properties of the mutant of MR in which His 297 has been converted to asparagine by site-directed mutagenesis (H297N). The structure of H297N, solved by molecular replacement at 2.2-{angstrom} resolution, reveals that no conformational alterations accompany the substitution. As expected, h297N has no detectable MR activity. However, H297N catalyzes the stereospecific elimination of bromide ion from racemic {rho}-(bromomethyl) mandelate to give {rho}-(methyl)-benzoylformate in 45% yield at a rate equal to that measured for wild-type enzyme. The pD dependence of the rate of the exchange reaction catalyzed by H297N reveals a pK{sub a} of 6.4 in D{sub 2}O which is assigned to Lys 166. These observations provide persuasive evidence that the reaction catalyzed by MR does, in fact, proceed via a two-base mechanism in which Lys 166 abstracts the {alpha}-proton from (S)-mandelate and His 297 abstracts the {alpha}-proton from (R)-mandelate. These studies demonstrate the power of site-directed mutagenesis in providing otherwise inaccessible detail about the mechanism of an enzyme-catalyzed reaction.

  3. Ammonia and hydrazine. Transition-metal-catalyzed hydroamination and metal-free catalyzed functionalization

    Energy Technology Data Exchange (ETDEWEB)

    Bertrand, Guy [Univ. of California, San Diego, CA (United States)

    2012-06-29

    high temperatures and long reaction times. To address this issue, we have developed several new families of carbon- and boron-based ligands, which are even better donors. The corresponding metal complexes (particularly gold, rhodium, iridium, and ruthenium) of all these species will be tested in the Markovnikov and anti-Markovnikov hydroamination of alkynes, allenes, and also alkenes with ammonia and hydrazine. We will also develop metal-free catalytic processes for the functionalization of ammonia and hydrazine. By possessing both a lone pair of electrons and an accessible vacant orbital, singlet carbenes resemble and can mimic the chemical behavior of transition metals. Our preliminary results demonstrate that specially designed carbenes can split the N–H bond of ammonia by an initial nucleophilic activation that prevents the formation of Lewis acid-base adducts, which is the major hurdle for the transition metal catalyzed functionalization of NH3. The use of purely organic compounds as catalysts will eliminate the major drawbacks of transition-metal-catalysis technology, which are the excessive cost of metal complexes (metal + ligands) and in many cases the toxicity of the metal.

  4. Gold-catalyzed cyclization reactions of allenol and alkynol derivatives.

    Science.gov (United States)

    Alcaide, Benito; Almendros, Pedro

    2014-03-18

    Although gold is chemically inert as a bulk metal, the landmark discovery that gold nanoparticles can be effective catalysts has opened up new and exciting research opportunities in the field. In recent years, there has been growth in the number of reactions catalyzed by gold complexes [gold(I) and gold(III)], usually as homogeneous catalysts, because they are soft Lewis acids. In addition, alkynes and allenes have interesting reactivities and selectivities, notably their ability to produce complex structures in very few steps. In this Account, we describe our work in gold catalysis with a focus on the formation of C-C and C-O bonds using allenes and alkynes as starting materials. Of these, oxa- and carbo-cyclizations are perhaps the best known and most frequently studied. We have divided those contributions into sections arranged according to the nature of the starting material (allene versus alkyne). Gold-catalyzed carbocyclizations in allenyl C2-linked indoles, allenyl-β-lactams, and allenyl sugars follow different mechanistic pathways. The cyclization of indole-tethered allenols results in the efficient synthesis of carbazole derivatives, for example. However, the compound produced from gold-catalyzed 9-endo carbocyclization of (aryloxy)allenyl-tethered 2-azetidinones is in noticeable contrast to the 5-exo hydroalkylation product that results from allenyl sugars. We have illustrated the unusual preference for the 4-exo-dig cyclization in allene chemistry, as well as the rare β-hydride elimination reaction, in gold catalysis from readily available α-allenols. We have also observed in γ-allenols that a (methoxymethyl)oxy protecting group not only masks a hydroxyl functionality but also exerts directing effects as a controlling unit in a gold-catalyzed regioselectivity reversal. Our recent work has also led to a combined experimental and computational study on regioselective gold-catalyzed synthetic routes to 1,3-oxazinan-2-ones (kinetically controlled

  5. Acid-Catalyzed Preparation of Biodiesel from Waste Vegetable Oil: An Experiment for the Undergraduate Organic Chemistry Laboratory

    Science.gov (United States)

    Bladt, Don; Murray, Steve; Gitch, Brittany; Trout, Haylee; Liberko, Charles

    2011-01-01

    This undergraduate organic laboratory exercise involves the sulfuric acid-catalyzed conversion of waste vegetable oil into biodiesel. The acid-catalyzed method, although inherently slower than the base-catalyzed methods, does not suffer from the loss of product or the creation of emulsion producing soap that plagues the base-catalyzed methods when…

  6. Novel CoIII complexes containing fluorescent coumarin-N-acylhydrazone hybrid ligands: Synthesis, crystal structures, solution studies and DFT calculations

    Science.gov (United States)

    Areas, Esther S.; Bronsato, Bruna Juliana da S.; Pereira, Thiago M.; Guedes, Guilherme P.; Miranda, Fábio da S.; Kümmerle, Arthur E.; da Cruz, Antônio G. B.; Neves, Amanda P.

    2017-12-01

    A series of new CoIII complexes of the type [Co(dien)(L1 -L3)]ClO4 (1-3), containing fluorescent coumarin-N-acylhydrazonate hybrid ligands, (E)-N‧-(1-(7-oxido-2-oxo-2H-chromen-3-yl)ethylidene)-4-R-benzohydrazonate [where R = H (L12 -), OCH3 (L22 -) or Cl (L32 -)], were obtained and isolated in the low spin CoIII configuration. Single-crystal X-ray diffraction showed that the coumarin-N-acylhydrazones act as tridentate ligands in their deprotonated form (L2 -). The cation (+ 1) complexes contain a diethylenetriamine (dien) as auxiliary ligand and their structures were calculated by DFT studies which were also performed for the CoII (S = 1/2 and S = 3/2) configurations. The LS CoII (S = 1/2) concentrated the spin density on the O-Co-O axis while the HS CoII (S = 3/2) exhibited a broad spin density distribution around the metallic center. Cyclic voltammetry studies showed that structural modifications made in the L2 - ligands caused a slight influence on the electronic density of the metal center, and the E1/2 values for the CoIII/CoII redox couple increased following the electronic effect of the R-substituent, in the order: 2 (R = OCH3) < 1 (R = H) < 3 (R = Cl). The theoretical redox potentials (E°) of the process CoIII → CoII were calculated for both CoII spin states (S = 1/2 and S = 3/2) and a better correlation was found for CoIII → CoII (S = 1/2), compared with experimental values vs SHE (E°calc = - 0.37, - 0.36 and - 0.32 V vs E°exp. = - 0.371, - 0.406 and - 0.358 V, for 1-3 respectively). Complexes 1-3 exhibited a very intense absorption band around 470 nm, assigned by DFT calculations as π-π* transitions from the delocalized coumarin-N-acylhydrazone system. 1-3 were very stable in MeOH for several days. Likewise, 1-3 were stable in phosphate buffer containing sodium ascorbate after 15 h, which was attributed to the high chelate effect and σ-donor ability of the L2 - and dien ligands.

  7. Nano composite system based on coumarin derivative–titanium dioxide nanoparticles and ionic liquid: Determination of levodopa and carbidopa in human serum and pharmaceutical formulations

    Energy Technology Data Exchange (ETDEWEB)

    Mazloum-Ardakani, Mohammad, E-mail: mazloum@yazd.ac.ir; Khoshroo, Alireza

    2013-10-10

    Graphical abstract: -- Highlights: •Nanostructured electrochemical sensor based on TiO{sub 2} and ionic liquid was used for the determination of levodopa in the presence of carbidopa. •Selectivity, reproducibility and low detection limit make the nanostructured modified electrode very useful for accurate determination of levodopa. •This sensor was applied in determination of levodopa and carbidopa in pharmaceutical formulations, blood serum and urine. -- Abstract: The combination of coumarin derivative (7-(1,3-dithiolan-2-yl)-9,10-dihydroxy-6H-benzofuro[3,2-c]chromen-6-on), (DC)–titanium dioxide nanoparticles (TiO{sub 2}) and ionic liquid (IL) yields nanostructured electrochemical sensor, formed a novel kind of structurally uniform and electrocatalytic activity material. This new ionic liquid–TiO{sub 2} nanoparticles modified carbon paste electrode (IL–CTP) due to its enhanced conductivity presented very large current response from electroactive substrates. The modified electrode was characterized by different methods including a scanning electron microscope (SEM), electrochemical impedance spectroscopy (EIS) and voltammetry. A pair of well-defined quasi reversible redox peaks of coumarin derivative was obtained at the modified carbon paste electrode (DC/IL–CTP) by direct electron transfer between the coumarin derivative and the CP electrode. Dramatically enhanced electrocatalytic activity was exemplified at the DC/IL–CTP electrode, as an electrochemical sensor to study the electro oxidation of levodopa (LD) and carbidopa (CD). Based on differential pulse voltammetry (DPV), the oxidation of LD and CD exhibited the dynamic range between 0.10– 900.0 μM and 20.0–900.0 μM respectively, and the detection limit (3σ) for LD and CD were 41 nM and 0.38 μM, respectively. DPV was used for simultaneous determination of LD and CD at the DC/IL–CTP electrode, and quantitation of LD and CD in some real samples (such as tablets of Parkin-C Fort and Madopar

  8. Development and industrial application of catalyzer for low-temperature hydrogenation hydrolysis of Claus tail gas

    Directory of Open Access Journals (Sweden)

    Honggang Chang

    2015-10-01

    Full Text Available With the implementation of more strict national environmental protection laws, energy conservation, emission reduction and clean production will present higher requirements for sulfur recovery tail gas processing techniques and catalyzers. As for Claus tail gas, conventional hydrogenation catalyzers are gradually being replaced by low-temperature hydrogenation catalyzers. This paper concentrates on the development of technologies for low-temperature hydrogenation hydrolysis catalyzers, preparation of such catalyzers and their industrial application. In view of the specific features of SO2 hydrogenation and organic sulfur hydrolysis during low-temperature hydrogenation, a new technical process involving joint application of hydrogenation catalyzers and hydrolysis catalyzers was proposed. In addition, low-temperature hydrogenation catalyzers and low-temperature hydrolysis catalyzers suitable for low-temperature conditions were developed. Joint application of these two kinds of catalyzers may reduce the inlet temperatures in the conventional hydrogenation reactors from 280 °C to 220 °C, at the same time, hydrogenation conversion rates of SO2 can be enhanced to over 99%. To further accelerate the hydrolysis rate of organic sulfur, the catalyzers for hydrolysis of low-temperature organic sulfur were developed. In lab tests, the volume ratio of the total sulfur content in tail gas can be as low as 131 × 10−6 when these two kinds of catalyzers were used in a proportion of 5:5 in volumes. Industrial application of these catalyzers was implemented in 17 sulfur recovery tail gas processing facilities of 15 companies. As a result, Sinopec Jinling Petrochemical Company had outstanding application performances with a tail gas discharging rate lower than 77.9 mg/m3 and a total sulfur recovery of 99.97%.

  9. Energy harvesting by implantable abiotically catalyzed glucose fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Kerzenmacher, S.; von Stetten, F. [Laboratory for MEMS Applications, Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Koehler-Allee 106, D-79110 Freiburg (Germany); Ducree, J. [HSG-IMIT, Wilhelm-Schickard-Str. 10, D-78052 Villingen-Schwenningen (Germany); Zengerle, R. [Laboratory for MEMS Applications, Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Koehler-Allee 106, D-79110 Freiburg (Germany); HSG-IMIT, Wilhelm-Schickard-Str. 10, D-78052 Villingen-Schwenningen (Germany)

    2008-07-15

    Implantable glucose fuel cells are a promising approach to realize an autonomous energy supply for medical implants that solely relies on the electrochemical reaction of oxygen and glucose. Key advantage over conventional batteries is the abundant availability of both reactants in body fluids, rendering the need for regular replacement or external recharging mechanisms obsolete. Implantable glucose fuel cells, based on abiotic catalysts such as noble metals and activated carbon, have already been developed as power supply for cardiac pacemakers in the late-1960s. Whereas, in vitro and preliminary in vivo studies demonstrated their long-term stability, the performance of these fuel cells is limited to the {mu}W-range. Consequently, no further developments have been reported since high-capacity lithium iodine batteries for cardiac pacemakers became available in the mid-1970s. In recent years research has been focused on enzymatically catalyzed glucose fuel cells. They offer higher power densities than their abiotically catalyzed counterparts, but the limited enzyme stability impedes long-term application. In this context, the trend towards increasingly energy-efficient low power MEMS (micro-electro-mechanical systems) implants has revived the interest in abiotic catalysts as a long-term stable alternative. This review covers the state-of-the-art in implantable abiotically catalyzed glucose fuel cells and their development since the 1960s. Different embodiment concepts are presented and the historical achievements of academic and industrial research groups are critically reviewed. Special regard is given to the applicability of the concept as sustainable micro-power generator for implantable devices. (author)

  10. A SABATH Methyltransferase from the moss Physcomitrella patens catalyzes

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Nan [ORNL; Ferrer, Jean-Luc [Universite Joseph Fourier, France; Moon, Hong S [Department of Plant Sciences, University of Tennessee; Kapteyn, Jeremy [Institute of Biological Chemistry, Washington State University; Zhuang, Xiaofeng [Department of Plant Sciences, University of Tennessee; Hasebe, Mitsuyasu [Laboratory of Evolutionary Biology, National Institute for Biology, 38 Nishigounaka; Stewart, Neal C. [Department of Plant Sciences, University of Tennessee; Gang, David R. [Institute of Biological Chemistry, Washington State University; Chen, Feng [University of Tennessee, Knoxville (UTK)

    2012-01-01

    Known SABATH methyltransferases, all of which were identified from seed plants, catalyze methylation of either the carboxyl group of a variety of low molecular weight metabolites or the nitrogen moiety of precursors of caffeine. In this study, the SABATH family from the bryophyte Physcomitrella patens was identified and characterized. Four SABATH-like sequences (PpSABATH1, PpSABATH2, PpSABATH3, and PpSABATH4) were identified from the P. patens genome. Only PpSABATH1 and PpSABATH2 showed expression in the leafy gametophyte of P. patens. Full-length cDNAs of PpSABATH1 and PpSABATH2 were cloned and expressed in soluble form in Escherichia coli. Recombinant PpSABATH1 and PpSABATH2 were tested for methyltransferase activity with a total of 75 compounds. While showing no activity with carboxylic acids or nitrogen-containing compounds, PpSABATH1 displayed methyltransferase activity with a number of thiols. PpSABATH2 did not show activity with any of the compounds tested. Among the thiols analyzed, PpSABATH1 showed the highest level of activity with thiobenzoic acid with an apparent Km value of 95.5 lM, which is comparable to those of known SABATHs. Using thiobenzoic acid as substrate, GC MS analysis indicated that the methylation catalyzed by PpSABATH1 is on the sulfur atom. The mechanism for S-methylation of thiols catalyzed by PpSABATH1 was partially revealed by homology-based structural modeling. The expression of PpSABATH1 was induced by the treatment of thiobenzoic acid. Further transgenic studies showed that tobacco plants overexpressing PpSABATH1 exhibited enhanced tolerance to thiobenzoic acid, suggesting that PpSABATH1 have a role in the detoxification of xenobiotic thiols.

  11. [The behavior of blood clotting and its inhibitors under long term treatment with 5,6-benzo-alpha-pyrone (coumarin). Double blind study].

    Science.gov (United States)

    Köstering, H; Bandura, B; Merten, H A; Wieding, J U

    1985-01-01

    The analyses on hemostaseological variables are recorded in connection with blood tests in the course of a double-blind study in 41 patients suffering from chronic venous insufficiency of higher degrees of severity. They were treated in addition to compression measures with two active ingredients, a coumarin (5,6-benzo-alpha-pyrone)/troxerutin combination (Venalot Depot) (n = 20) or benzarone (n = 21) receiving 3 X 2 dragees daily for 6 weeks. Good clinical efficacy and the improvement of symptoms were observed together with almost no side-effects. The coagulation analysis showed no influence of the active principles on the global coagulation or the clotting factors and the inhibitors and factors of the fibrinolysis. In particular there was no phenprocoumon-like effect on the blood clotting system.

  12. Osthole, a natural coumarin, improves neurobehavioral functions and reduces infarct volume and matrix metalloproteinase-9 activity after transient focal cerebral ischemia in rats.

    Science.gov (United States)

    Mao, Xuexuan; Yin, Wei; Liu, Mengfei; Ye, Minzhong; Liu, Peiqing; Liu, Jianxin; Lian, Qishen; Xu, Suowen; Pi, Rongbiao

    2011-04-18

    Previously we demonstrated that Osthole, a natural coumarin, protects against focal cerebral ischemia/reperfusion-induced injury in rats. In the present study, the effects of Osthole on neurobehavioral functions, infarct volume and matrix metalloproteinase-9 (MMP-9) in a rat 2h focal cerebral ischemia model were investigated. Osthole (100mg/kg per dose) was administrated intraperitoneally 30min before ischemic insult and immediately after reperfusion. Osthole treatment significantly reduced neurological deficit score and infarct volume by 38.5% and 33.8%, respectively, as compared with the untreated animals. Osthole reversed ischemia-reperfusion-induced increase in MMP-9 protein level/activity as evidenced by Western blotting and gelatin zymography. Taken together, these results for the first time demonstrate that Osthole reduces infarct volume, restores neurobehavioral functions and downregulates MMP-9 protein level/activity in ischemia/reperfused brain. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Preparative isolation and purification of coumarins from Angelica dahurica (Fisch. ex Hoffn) Benth, et Hook. f (Chinese traditional medicinal herb) by high-speed counter-current chromatography.

    Science.gov (United States)

    Liu, Renmin; Li, Aifeng; Sun, Ailing

    2004-10-15

    A preparative high-speed counter-current chromatography (HSCCC) method for isolation and purification of coumarins from Angelica dahurica (Fisch. ex Hoffin) Benth, et Hook. f(Baizhi in Chinese) was successfully established by using n-hexane-methanol-water as the two-phase solvent system in gradient elution mode. The upper phase of n-hexane-methanol-water (5:5:5, v/v) was used as the stationary phase of HSCCC. The mobile phase used in HSCCC was the lower phase of n-hexane-methanol-water (5:5:5, v/v) and n-hexane-methanol-water (5:7:3, v/v) that was changed in gradient. Three major components including imperatorin, isoimperatorin and oxypeucedanine were isolated, each at over 98% purity as determined by high-performance liquid chromatography (HPLC). The peak fractions of HSCCC were identified by 1H-NMR and 13C-NMR.

  14. Palladium-Catalyzed Directed Halogenation of Bipyridine N-Oxides.

    Science.gov (United States)

    Zucker, Sina P; Wossidlo, Friedrich; Weber, Manuela; Lentz, Dieter; Tzschucke, C Christoph

    2017-06-02

    The palladium-catalyzed directed C-H halogenation of bipyridine N-oxides was investigated. Using NCS or NBS (N-chloro- or N-bromosuccinimide) and 5 mol % Pd(OAc)2 in chlorobenzene (0.10 molar) at 110 °C, pyridine-directed functionalization took place and 3-chloro- or 3-bromobipyridine N-oxides were obtained in high yields. The reaction is sensitive to steric hindrance by 4- and 6'-substituents. Only in the latter case, where coordination of palladium by the pyridine is hindered, 3'-halogenation directed by the N-oxide function was observed. The halogenated products were deoxygenated by PCl3 or PBr3.

  15. Zinc oxide catalyzed growth of single-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Gao Fenglei, E-mail: jsxzgfl@sina.com [Nanomaterials and Chemistry Key Laboratory, Wenzhou University, Wenzhou 325027 (China); Zhang Lijie; Huang Shaoming [Nanomaterials and Chemistry Key Laboratory, Wenzhou University, Wenzhou 325027 (China)

    2010-02-01

    We demonstrate that zinc oxide can catalyze the growth of single-walled carbon nanotubes (SWNTs) with high efficiency by a chemical vapor deposition process. The zinc oxide nanocatalysts, prepared using a diblock copolymer templating method and characterized by atomic force microscopy (AFM), were uniformly spaced over a large deposition area with an average diameter of 1.7 nm and narrow size distribution. Dense and uniform SWNTs films with high quality were obtained by using a zinc oxide catalyst, as characterized by scanning electron microscopy (SEM), Raman spectroscopy, AFM, and high-resolution transmission electron microscopy (HRTEM).

  16. Polyoxometalates as mediators in the laccase catalyzed delignification

    OpenAIRE

    Balakshin, M. Yu.; Evtuguin, D. V.; Neto, C. Pascoal; Paulo, Artur Cavaco

    2001-01-01

    The polyoxometalate (POM)-laccase catalytic system was applied for the first time to aerobic delignification of kraft pulps at moderate (40-60 degreesC) temperatures. Laccase was found to readily catalyze the re-oxidation of different kinds of polyoxometalates, including those, which cannot be re-oxidized by dioxygen even at high temperatures (PMo11V1, SiW11V1. etc.). This allows a sequence of catalytic redox cycles similar to that in the laccase-mediator system (LMS) where electrons are tran...

  17. Ketone-catalyzed photochemical C(sp3)-H chlorination.

    Science.gov (United States)

    Han, Lei; Xia, Jibao; You, Lin; Chen, Chuo

    2017-06-29

    Photoexcited arylketones catalyze the direct chlorination of C(sp3)-H groups by N-chlorosuccinimide. Acetophenone is the most effective catalyst for functionalization of unactivated C-H groups while benzophenone provides better yields for benzylic C-H functionalization. Activation of both acetophenone and benzophenone can be achieved by irradiation with a household compact fluorescent lamp. This light-dependent reaction provides a better control of the reaction as compared to the traditional chlorination methods that proceed through a free radical chain propagation mechanism.

  18. Iodine - catalyzed prins cyclization of aliphatic and aromatic ketones

    Energy Technology Data Exchange (ETDEWEB)

    Kishore, K.R.; Reddy, K.; Silva Junior, Luiz F., E-mail: luizfsjr@iq.usp.br [Universidade de Sao Paulo (IQ/USP), SP (Brazil). Inst. de Quimica. Dept. de Quimica Fundamental

    2013-09-15

    Iodine-catalyzed Prins cyclization of homoallylic alcohols and ketones was investigated. Anhydrous conditions and inert atmosphere are not required in this metal-free protocol. The reaction of 2-(3,4-dihydronaphthalene-1-yl)propan-1-ol with six aliphatic symmetric ketones gave the desired products in 67-77% yield. Cyclization was performed with four aliphatic unsymmetric ketones, leading to corresponding pyrans in 66-76% yield. Prins cyclization was also accomplished with four aromatic ketones in 37-66% yield. Finally, Prins cyclization of the monoterpene isopulegol and acetone was successfully achieved. (author)

  19. Asymmetric Propargylation of Ketones using Allenylboronates Catalyzed by Chiral Biphenols

    Science.gov (United States)

    Barnett, David S.; Schaus, Scott E.

    2011-01-01

    Chiral biphenols catalyze the enantioselective asymmetric propargylation of ketones using allenylboronates. The reaction uses 10 mol % of 3,3′-Br2-BINOL as the catalyst and allenyldioxoborolane as the nucleophile, in the absence of solvent, and under microwave irradiation to afford the homopropargylic alcohol. The reaction products are obtained in good yields (60 – 98%) and high enantiomeric ratios (3:1 – 99:1). Diastereoselective propargylations using chiral racemic allenylboronates result in good diastereoselectivities (dr > 86:14) and enantioselectivities (er > 92:8) under the catalytic conditions. PMID:21732609

  20. Comparing Ru and Fe-catalyzed olefin metathesis

    KAUST Repository

    Poater, Albert

    2014-01-01

    Density functional theory calculations have been used to explore the potential of Fe-based complexes with an N-heterocyclic carbene ligand, as olefin metathesis catalysts. Apart from a less endothermic reaction energy profile, a small reduction in the predicted upper energy barriers (≈ 2 kcal mol -1) is calculated in the Fe catalyzed profile with respect to the Ru catalysed profile. Overall, this study indicates that Fe-based catalysts have the potential to be very effective olefin metathesis catalysts. This journal is © the Partner Organisations 2014.

  1. Zeolite-catalyzed isomerization of tetroses in aqueous medium

    DEFF Research Database (Denmark)

    Shunmugavel, Saravanamurugan; Riisager, Anders

    2014-01-01

    in water. Hence, the results demonstrate water to be a preferred solvent compared to lower alcohols for zeolite-catalyzed tetrose isomerization, which is opposite to what previously have been found for analogous pentose and hexose isomerization. A reuse study revealed further that H-USY(6) could be applied...... in at least five reaction runs with essentially unchanged activity and without significant aluminium leaching from the catalyst. The use of benign reaction conditions and an industrially pertinent solid catalyst in combination with water establishes a new, green tetrose isomerization protocol...

  2. Deoxyribonucleoside kinases: two enzyme families catalyze the same reaction.

    Science.gov (United States)

    Sandrini, Michael P B; Piskur, Jure

    2005-05-01

    Mammals have four deoxyribonucleoside kinases, the cytoplasmic (TK1) and mitochondrial (TK2) thymidine kinases, and the deoxycytidine (dCK) and deoxyguanosine (dGK) kinases, which salvage the precursors for nucleic acids synthesis. In addition to the native deoxyribonucleoside substrates, the kinases can phosphorylate and thereby activate a variety of anti-cancer and antiviral prodrugs. Recently, the crystal structure of human TK1 has been solved and has revealed that enzymes with fundamentally different origins and folds catalyze similar, crucial cellular reactions.

  3. Ruthenium-Catalyzed Dehydrogenative Decarbonylation of Primary Alcohols

    DEFF Research Database (Denmark)

    Mazziotta, Andrea; Madsen, Robert

    2017-01-01

    Dehydrogenative decarbonylation of a primary alcohol involves the release of both dihydrogen and carbon monoxide to afford the one-carbon shorter product. The transformation has now been achieved with a ruthenium-catalyzed protocol by using the complex Ru(COD)Cl2 and the hindered monodentate ligand...... P(o-tolyl)3 in refluxing p-cymene. The reaction can be applied to both benzylic and long chain linear aliphatic alcohols. The intermediate aldehyde can be observed during the transformation, which is therefore believed to proceed through two separate catalytic cycles involving first dehydrogenation...... of the alcohol and then decarbonylation of the resulting aldehyde....

  4. Synthesis of Dihydrobenzofurans via Palladium-Catalyzed Heteroannulations

    Energy Technology Data Exchange (ETDEWEB)

    Rozhkov, Roman Vladimirovich [Iowa State Univ., Ames, IA (United States)

    2004-01-01

    Palladium-catalyzed heteroannulation of 1,3-dienes with 3-iodo-2-alkenols, and 2-iodo-2-alkenols, as well as their amino analogs, affords the corresponding cyclic ethers and amines respectively. The presence of a β-hydrogen in the vinylic halide results in β-hydride elimination giving the corresponding alkyne. The presence of a bulky group in the α-position of the vinylic halide results in failure or reduced amounts of annulation products. A chloride source, pyridine base and electron-rich phosphine are essential for this reaction.

  5. Reactivity of bromoselenophenes in palladium-catalyzed direct arylations

    Directory of Open Access Journals (Sweden)

    Aymen Skhiri

    2017-12-01

    Full Text Available The reactivity of 2-bromo- and 2,5-dibromoselenophenes in Pd-catalyzed direct heteroarylation was investigated. From 2-bromoselenophene, only the most reactive heteroarenes could be employed to prepare 2-heteroarylated selenophenes; whereas, 2,5-dibromoselenophene generally gave 2,5-di(heteroarylated selenophenes in high yields using both thiazole and thiophene derivatives. Moreover, sequential catalytic C2 heteroarylation, bromination, catalytic C5 arylation reactions allowed the synthesis of unsymmetrical 2,5-di(heteroarylated selenophene derivatives in three steps from selenophene.

  6. Palladium-Catalyzed alpha-Arylation of Tetramic Acids

    DEFF Research Database (Denmark)

    Storgaard, Morten; Dorwald, F. Z.; Peschke, B.

    2009-01-01

    A mild, racemization-free, palladium-Catalyzed alpha-arylation of tetramic acids (2,4-pyrrolidinediones) has been developed. Various amino acid-derived tetramic acids were cleanly arylated by treatment with 2 mol % of Pd(OAc)(2), 4 mol % of a sterically demanding biaryl phosphine, 2.3 equiv of K2...... no effect on their reactivity: both electron-rich and electron-poor aryl chlorides and bromides or triflates led to good yields. Ortho-substituted aryl halides and heteroaryl halides, however, did not undergo the title reaction....

  7. FBH1 Catalyzes Regression of Stalled Replication Forks

    DEFF Research Database (Denmark)

    Fugger, Kasper; Mistrik, Martin; Neelsen, Kai J

    2015-01-01

    DNA replication fork perturbation is a major challenge to the maintenance of genome integrity. It has been suggested that processing of stalled forks might involve fork regression, in which the fork reverses and the two nascent DNA strands anneal. Here, we show that FBH1 catalyzes regression...... of a model replication fork in vitro and promotes fork regression in vivo in response to replication perturbation. Cells respond to fork stalling by activating checkpoint responses requiring signaling through stress-activated protein kinases. Importantly, we show that FBH1, through its helicase activity...... a model whereby FBH1 promotes early checkpoint signaling by remodeling of stalled DNA replication forks....

  8. Muon-catalyzed fusion in deuterium at 3 K

    Energy Technology Data Exchange (ETDEWEB)

    Knowles, P.E.; Beer, G.A.; Mason, G.R.; Porcelli, T.A. [Victoria Univ., BC (Canada); Bailey, J.M. [EA Technology, Capenhurst (United Kingdom); Beveridge, J.L.; Marshall, G.M.; Mulhauser, F.; Olin, A. [British Columbia Univ., Vancouver, BC (Canada). TRIUMF Facility; Fujiwara, M.C. [British Columbia Univ., Vancouver, BC (Canada); Huber, T.M. [Gustavus Adolphus Coll., St. Peter, MN (United States); Jacot-Guillarmod, R. [Fribourg Univ. (Switzerland); Kammel, P. [Lawrence Berkeley Lab., CA (United States); Kim, S.K. [Jeonbuk National Univ. (Korea, Republic of); Kunselman, A.R. [Wyoming Univ., Laramie, WY (United States); Martoff, C.J. [Temple Univ., Philadelphia, PA (United States); Petitjean, C. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Zmeskal, J. [Oesterreichische Akademie der Wissenschaften, Vienna (Austria)

    1996-10-01

    Muon-catalyzed fusion in deuterium has traditionally been studied in gaseous and liquid targets. The TRIUMF solid hydrogen layer target system has been used to study the fusion reaction rates in the solid phase at a target temperature of 3 K. Both branches of the cycle were observed; neutrons by a liquid organic scintillator, and protons by a silicon detector located inside the target system. The effective molecular formation rate from the upper hyperfine state and the spin exchange rate have been measured, and information on the branching ratio parameters has been extracted. (orig.). 21 refs.

  9. Ternary Organic Solar Cells with Coumarin7 as the Donor Exhibiting Greater Than 10% Power Conversion Efficiency and a High Fill Factor of 75.

    Science.gov (United States)

    Chen, Xin-Wei; Tao, Si-Lu; Fan, Cong; Chen, Dong-Cheng; Zhou, Ling; Lin, Hui; Zheng, Cai-Jun; Su, Shi-Jian

    2017-09-06

    Ternary bulk heterojunction (BHJ) is a brilliant photovoltaic technology for improving the performance of organic solar cells (OSCs), because the light absorption range can be significantly extended by using multiple donors or acceptor materials. In this paper, coumarin7 (C7), a small organic molecule typical led used in organic light-emitting diodes, was initially exploited as second electron-donor component in ternary bulk heterojunction OSCs along with conventional blend system spolythieno[3,4-b]-thiophene/benzodithiophene(PTB7) and [6,6]-phenyl-C71 -butyric acid methyl(PC 71 BM). A champion PCE value of 10.28% was realized in the ternary OSCs when incorporated with 10 wt % C7 doping ratio in the donors, corresponding to about 35% enhancement compared with the PTB7:PC 71 BM-based OSCs, a high fill factor (FF) of 75.03%, a short-circuit currentdensity (J sc ) of 18.72 mA cm -2 and an open-circuit voltage (V oc ) of 0.73 V. The enhanced performance of the ternary OSCs can be attributed to the simultaneous improvement of the FF and the J sc . In addition to extended light absorption, a perfect nanofiber filament active layer morphology is obtained due to the good compatibility between C7 and PTB7, which facilitates the balance of charge transportation and the suppression of charge recombination. This investigation suggests that coumarin derivatives, which have completely different structure with polymer donors, can also be used to fabricate ternary solar cells and have the potential applications to obtain amazing performance after further device engineering and optimization.

  10. The effect of complementary and alternative medicines on CYP3A4-mediated metabolism of three different substrates: 7-benzyloxy-4-trifluoromethyl-coumarin, midazolam and docetaxel.

    Science.gov (United States)

    Mooiman, Kim D; Maas-Bakker, Roel F; Hendrikx, Jeroen J M A; Bank, Paul C D; Rosing, Hilde; Beijnen, Jos H; Schellens, Jan H M; Meijerman, Irma

    2014-06-01

    Concomitant use of complementary and alternative medicine (CAM) and anticancer drugs can affect the pharmacokinetics of anticancer drugs by inhibiting the metabolizing enzyme cytochrome P450 3A4 (CYP3A4) (EC 1.14.13.157). Several in vitro studies determined whether CAM can inhibit CYP3A4, but these studies revealed contradictory results. A plausible explanation for these conflicting results is the use only of a single model CYP3A4 substrate in each study. Therefore, the objective was to determine the potential of selected CAM (β-carotene, Echinacea, garlic, Ginkgo biloba, ginseng, grape seed extract, green tea extract, milk thistle, saw palmetto, valerian, vitamin B6, B12 and C) to inhibit CYP3A4-mediated metabolism of different substrates: 7-benzyloxy-4-trifluoromethyl-coumarin (BFC), midazolam and docetaxel. The effect of CAM on CYP3A4-mediated metabolism of an anticancer drug has never been determined before in vitro, which makes this study unique. The oncolytic CYP3A4 substrate docetaxel was used to establish the predictive value of the model substrates for pharmacokinetic interactions between CAM and anticancer drugs in vitro, and to more closely predict these interactions in vivo. The inhibition of CYP3A4-mediated metabolism of 7-benzyloxy-4-trifluoromethyl-coumarin (BFC) by CAM was assessed in Supersomes, using the fluorometric CYP3A4 inhibition assay. In human liver microsomes (HLM) the inhibition of CYP3A4-mediated metabolism of midazolam and docetaxel was determined, using liquid-chromatography coupled to tandem mass spectrometry (LC-MS/MS). The results confirmed grape seed and green tea as potent inhibitors and milk thistle as moderate inhibitor of CYP3A4-mediated metabolism of BFC, midazolam and docetaxel. Clinical studies are required to determine the clinical relevance of the determined CYP3A4 inhibition by grape seed, green tea and milk thistle. © 2014 Royal Pharmaceutical Society.

  11. Evaluation of sesquiterpene coumarins from Ferula assa-foetida on VEGF, MMP9, MMP2 and study of biding modes using computational methods

    Directory of Open Access Journals (Sweden)

    Kh. Almasi

    2017-11-01

    Full Text Available Background and objectives: Ferula assafoetida of Apiaceae family bears sesquiterpene coumarins from phenolic class. Studies have shown that phenolic compounds at physiological concentration can inhibit two groups of gelatinase matrix metalloproteinases. So, the ability of compounds of this plant to inhibit the enzymes mentioned above seems to be useful. Methods: Acetone extract of plant was prepared and sesquiterpene coumarins were purified using column chromatography and HPLC preparative analyses and their structures were elucidated. After culturing the cell to proper confluence, the cells were isolated and the supernatant was removed. The pure substances were applied on cell lines U87MG and WEHI. In the computational part, the structure has been docked in the active site of metalloproteinase, and significant interactions were determined. Subsequently, ligand-protein complexes were subjected to molecular dynamics simulation in water and thermodynamic properties were calculated. Results: In the phytochemistry field galbanic acid, mogoltadone, kellerin, polyanthin and polyanthinin were extracted from F. assafoetida. Biological investigation demonstrated significant changes in the amount and activity of matrix metalloproteinase and vascular endothelial growth factor. Ligand binding to the active site of the protein was studied in computational causing conformational changes in the active site of the protein. Conclusion: Investigation revealed that the coumrins have inhibitory effects on the content and activity of MMP 2.9 and showed anti-angiogenetic effect. So, they can be potentially effective in the treatment of cancer. Interactive and competitive binding between MMP-9 and galbanic acid were studied with FT-IR, UV-Vis and fluorescence methods and MMP-9 structure was changed in these interactions.

  12. Application of stepwise gradients in counter-current chromatography: a rapid and economical strategy for the one-step separation of eight coumarins from Seseli resinosum.

    Science.gov (United States)

    Shehzad, Omer; Khan, Salman; Ha, In Jin; Park, Youmie; Tosun, Alev; Kim, Yeong Shik

    2013-10-04

    The targeted purification of compounds with a broad polarity range from traditional medicinal plants is a big challenge for counter-current chromatography (CCC). Gradient elution was introduced in CCC to address this problem. However, once a suitable solvent system is selected, the separation process requires optimization of operational parameters. The present study was conducted to optimize various operational parameters to integrate the flow rate and solvent gradients for the rapid isolation of eight coumarins from Seseli resinosum in a single run. An increase in the system temperature from 15°C to 35°C increased the stationary phase retention and solubility of the sample, whereas the operation time and viscosity of the system were decreased. The high purity of each compound was ensured by collecting the fractions from the main peaks while all the shoulder peaks were mixed and separated under the same conditions with semi-preparative CCC. GC-FID was used to analyze the components of each phase, which was prepared without presaturation to save the time and solvent consumption. Finally, eight coumarins were purified, including (1) d-laserpitin, (2) (3'S,4'S)-3'-angeloyloxy-4'-hydroxy-3',4'-dihydroseselin, (3) (+)-samidin, (4) (3'S,4'S)-3'-acetoxy-4'-angeloyloxy-3',4'-dihydroseselin, (5) deltoin (6), calipteryxin, (7) (3'S,4'S)-3',4'-disenecioyloxy-3',4'-dihydroseselin, and (8) (-)-anomalin. The present technique has successfully accomplished the goal of one-step separation of these compounds with high purity and recovery in an economic and time efficient manner. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Fe(II)/Fe(III)-Catalyzed Intramolecular Didehydro-Diels-Alder Reaction of Styrene-ynes.

    Science.gov (United States)

    Mun, Hyeon Jin; Seong, Eun Young; Ahn, Kwang-Hyun; Kang, Eun Joo

    2018-02-02

    The intramolecular didehydro-Diels-Alder reaction of styrene-ynes was catalyzed by Fe(II) and Fe(III) to produce various naphthalene derivatives under microwave heating conditions. Mechanistic calculations found that the Fe(II) catalyst activates the styrenyl diene in an inverse-electron-demand Diels-Alder reaction, and the consecutive dehydrogenation reaction can be promoted by either Fe(II)-catalyzed direct dehydrogenation or an Fe(III)-catalyzed rearomatization/dehydrogenation pathway.

  14. Organizational innovation: a comprehensive model for catalyzing organizational development and change in a rapidly changing world

    National Research Council Canada - National Science Library

    Steiber, Annika; Alänge, Sverker

    2015-01-01

    ..., especially the processes through which organizational innovations are created, diffused, and sustained. There is thus a need for a more comprehensive understanding of mechanisms catalyzing organizational development...

  15. Solid oxide fuel cell with internal reforming, catalyzed interconnect for use therewith, and methods

    Science.gov (United States)

    Liu, Di-Jia; Guan, Jie; Minh, Nguyen

    2010-06-08

    A catalyzed interconnect for an SOFC electrically connects an anode and an anodic current collector and comprises a metallic substrate, which provides space between the anode and anodic current collector for fuel gas flow over at least a portion of the anode, and a catalytic coating on the metallic substrate comprising a catalyst for catalyzing hydrocarbon fuel in the fuel gas to hydrogen rich reformate. An SOFC including the catalyzed anodic inter-connect, a method for operating an SOFC, and a method for making a catalyzed anodic interconnect are also disclosed.

  16. Electrochemical reduction of oxygen catalyzed by Pseudomonas aeruginosa

    Energy Technology Data Exchange (ETDEWEB)

    Cournet, Amandine [Universite de Toulouse, UPS, LU49, Adhesion bacterienne et formation de biofilms, 35 chemin des Maraichers, 31062 Toulouse Cedex 09 (France)] [Laboratoire de Genie Chimique CNRS UMR5503, 4 allee Emile Monso, BP 84234, 31432 Toulouse Cedex 04 (France); Berge, Mathieu; Roques, Christine [Universite de Toulouse, UPS, LU49, Adhesion bacterienne et formation de biofilms, 35 chemin des Maraichers, 31062 Toulouse Cedex 09 (France); Bergel, Alain [Laboratoire de Genie Chimique CNRS UMR5503, 4 allee Emile Monso, BP 84234, 31432 Toulouse Cedex 04 (France); Delia, Marie-Line, E-mail: marieline.delia@ensiacet.f [Laboratoire de Genie Chimique CNRS UMR5503, 4 allee Emile Monso, BP 84234, 31432 Toulouse Cedex 04 (France)

    2010-07-01

    Pseudomonas aeruginosa has already been shown to catalyze oxidation processes in the anode compartment of a microbial fuel cell. The present study focuses on the reverse capacity of the bacterium, i.e. reduction catalysis. Here we show that P. aeruginosa is able to catalyze the electrochemical reduction of oxygen. The use of cyclic voltammetry showed that, for a given range of potential values, the current generated in the presence of bacteria could reach up to four times the current obtained without bacteria. The adhesion of bacteria to the working electrode was necessary for the catalysis to be observed but was not sufficient. The electron transfer between the working electrode and the bacteria did not involve mediator metabolites like phenazines. The transfer was by direct contact. The catalysis required a certain contact duration between electrodes and live bacteria but after this delay, the metabolic activity of cells was no longer necessary. Membrane-bound proteins, like catalase, may be involved. Various strains of P. aeruginosa, including clinical isolates, were tested and all of them, even catalase-defective mutants, presented the same catalytic property. P. aeruginosa offers a new model for the analysis of reduction catalysis and the protocol designed here may provide a basis for developing an interesting tool in the field of bacterial adhesion.

  17. Catalyzed Synthesis of Zinc Clays by Prebiotic Central Metabolites.

    Science.gov (United States)

    Zhou, Ruixin; Basu, Kaustuv; Hartman, Hyman; Matocha, Christopher J; Sears, S Kelly; Vali, Hojatollah; Guzman, Marcelo I

    2017-04-03

    How primordial metabolic networks such as the reverse tricarboxylic acid (rTCA) cycle and clay mineral catalysts coevolved remains a mystery in the puzzle to understand the origin of life. While prebiotic reactions from the rTCA cycle were accomplished via photochemistry on semiconductor minerals, the synthesis of clays was demonstrated at low temperature and ambient pressure catalyzed by oxalate. Herein, the crystallization of clay minerals is catalyzed by succinate, an example of a photoproduced intermediate from central metabolism. The experiments connect the synthesis of sauconite, a model for clay minerals, to prebiotic photochemistry. We report the temperature, pH, and concentration dependence on succinate for the synthesis of sauconite identifying new mechanisms of clay formation in surface environments of rocky planets. The work demonstrates that seeding induces nucleation at low temperatures accelerating the crystallization process. Cryogenic and conventional transmission electron microscopies, X-ray diffraction, diffuse reflectance Fourier transformed infrared spectroscopy, and measurements of total surface area are used to build a three-dimensional representation of the clay. These results suggest the coevolution of clay minerals and early metabolites in our planet could have been facilitated by sunlight photochemistry, which played a significant role in the complex interplay between rocks and life over geological time.

  18. Ozonation of Indigo Carmine Catalyzed with Fe-Pillared Clay

    Directory of Open Access Journals (Sweden)

    Miriam Bernal

    2013-01-01

    Full Text Available The ozonation catalyzed by iron-pillared clays was studied. The degradation of dye indigo carmine (IC was elected as test reaction. Fe-pillared clays were synthesized by employing hydrolyzed FeCl3 solutions and bentonite. The pillared structure was verified by XRD and by XPS the oxidation state of iron in the synthesized material was established to be +2. By atomic absorption the weight percentage of iron was determined to be 16. The reaction was conducted in a laboratory scale up-flow bubble column reactor. From the studied variables the best results were obtained with a particle size of 60 microns, pH=3, ozone flow of 0.045 L/min, and catalyst concentration of 100 mg/L. IC was completely degraded and degradation rate was found to be double when using Fe-PILCS than with ozone alone. DQO reduction was also significantly higher with catalyzed than with noncatalyzed ozonation.

  19. Renalase does not catalyze the oxidation of catecholamines.

    Science.gov (United States)

    Beaupre, Brett A; Hoag, Matthew R; Moran, Graham R

    2015-08-01

    It is widely accepted that the function of human renalase is to oxidize catecholamines in blood. However, this belief is based on experiments that did not account for slow, facile catecholamine autoxidation reactions. Recent evidence has shown that renalase has substrates with which it reacts rapidly. The reaction catalyzed defines renalase as an oxidase, one that harvests two electrons from either 2-dihydroNAD(P) or 6-dihydroNAD(P) to form β-NAD(P)(+) and hydrogen peroxide. The apparent metabolic purpose of such a reaction is to avoid inhibition of primary dehydrogenase enzymes by these β-NAD(P)H isomers. This article demonstrates that renalase does not catalyze the oxidation of neurotransmitter catecholamines. Using high-performance liquid chromatography we show that there is no evidence of consumption of epinephrine by renalase. Using time-dependent spectrophotometry we show that the renalase FAD cofactor spectrum is unresponsive to added catecholamines, that adrenochromes are not observed to accumulate in the presence of renalase and that the kinetics of single turnover reactions with 6-dihydroNAD are unaltered by the addition of catecholamines. Lastly we show using an oxygen electrode assay that plasma renalase activity is below the level of detection and only when exogenous renalase and 6-dihydroNAD are added can dioxygen be observed to be consumed. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Time-dependent kinetic complexities in cholinesterase-catalyzed reactions.

    Science.gov (United States)

    Masson, P

    2012-10-01

    Cholinesterases (ChEs) display a hysteretic behavior with certain substrates and inhibitors. Kinetic cooperativity in hysteresis of ChE-catalyzed reactions is characterized by a lag or burst phase in the approach to steady state. With some substrates damped oscillations are shown to superimpose on hysteretic lags. These time dependent peculiarities are observed for both butyrylcholinesterase and acetylcholinesterase from different sources. Hysteresis in ChE-catalyzed reactions can be interpreted in terms of slow transitions between two enzyme conformers E and E'. Substrate can bind to E and/or E', both Michaelian complexes ES and Ε'S can be catalytically competent, or only one of them can make products. The formal reaction pathway depends on both the chemical structure of the substrate and the type of enzyme. In particular, damped oscillations develop when substrate exists in different, slowly interconvertible, conformational, and/or micellar forms, of which only the minor form is capable of binding and reacting with the enzyme. Biphasic pseudo-first-order progressive inhibition of ChEs by certain carbamates and organophosphates also fits with a slow equilibrium between two reactive enzyme forms. Hysteresis can be modulated by medium parameters (pH, chaotropic and kosmotropic salts, organic solvents, temperature, osmotic pressure, and hydrostatic pressure). These studies showed that water structure plays a role in hysteretic behavior of ChEs. Attempts to provide a molecular mechanism for ChE hysteresis from mutagenesis studies or crystallographic studies failed so far. In fact, several lines of evidence suggest that hysteresis is controlled by the conformation of His438, a key residue in the catalytic triad of cholinesterases. Induction time may depend on the probability of His438 to adopt the operative conformation in the catalytic triad. The functional significance of ChE hysteresis is puzzling. However, the accepted view that proteins are in equilibrium between

  1. Immobilization of Chiral Ferrocenyl Ligands on Silica Gel and their Testing in Pd-catalyzed Allylic Substitution and Rh-catalyzed Hydrogenation

    Directory of Open Access Journals (Sweden)

    Duncan J. Macquarrie

    2005-07-01

    Full Text Available Five different silica gels containing two chiral ferrocenyl ligands were prepared by various synthetic routes and tested in an enantioselective Pd(0-catalyzed allylic substitution and Rh-catalyzed hydrogenation. All the prepared anchored ligands were characterized by porosimetry data, DRIFTS spectra, thermal data and AAS. The aim of the work was to compare the influence of the carrier, surface properties and immobilization strategy on the performance of the catalyst.

  2. Kinetic study on the acid-catalyzed hydrolysis of cellulose to levulinic acid

    NARCIS (Netherlands)

    Girisuta, B.; Janssen, L. P. B. M.; Heeres, H. J.

    2007-01-01

    A variety of interesting bulk chemicals is accessible by the acid-catalyzed hydrolysis of cellulose. An interesting example is levulinic acid, a versatile precursor for fuel additives, polymers, and resins. A detailed kinetic study on the acid-catalyzed hydrolysis of cellulose to levulinic acid is

  3. Rendimento extrativo de cumarina de folhas de guaco (Mikania glomerata Sprengel submetidas a diferentes temperaturas de secagem Extraction yield of coumarin from guaco (Mikania glomerata Sprengel leaves subjected to different drying temperatures

    Directory of Open Access Journals (Sweden)

    L.L. Radünz

    2012-01-01

    Full Text Available O objetivo deste trabalho foi avaliar o efeito da temperatura do ar de secagem no rendimento extrativo da cumarina de folhas de guaco. Foram empregados 6 tratamentos de secagem, sendo ar ambiente, ar aquecido a 40, 50, 60, 70 e 80ºC. Utilizou-se secador de bandejas, tendo como fonte de aquecimento o gás liquefeito de petróleo (GLP. Os rendimentos extrativos da cumarina, depois de realizada a secagem, foram comparados com os valores obtidos da planta fresca (tratamento testemunha. A extração da cumarina foi realizada pelo método a quente, em banho-maria a 65ºC, sendo a identificação e quantificação realizada por cromatografia líquida de alta eficiência (CLAE. Em função dos resultados obtidos, pôde-se concluir que a temperatura do ar de secagem a 50ºC possibilitou o melhor resultado para o rendimento extrativo de cumarina em folhas de guaco.The aim of this study was to evaluate the effect of drying on the extraction yield of coumarin from guaco leaves. Six drying treatments were used, being room air, heated air at 40, 50, 60, 70 and 80ºC. A tray dryer was used with liquefied petroleum gas (LPG as heating source. The extraction yield of coumarin, after drying, was compared to the values obtained from the fresh plant (control treatment. Coumarin extraction was carried out by using the heat method, in water bath at 65ºC, and identification and quantification were done by means of high performance liquid chromatography (HPLC. Considering the obtained results, the temperature of the drying air at 50ºC led to the best result for the extraction yield of coumarin in guaco leaves.

  4. Towards a methanol economy: Zeolite catalyzed production of synthetic fuels

    DEFF Research Database (Denmark)

    Mentzel, Uffe Vie

    The main focus of this thesis is zeolite catalyzed conversion of oxygenates to hydrocarbon fuels and chemicals. Furthermore, conversion of ethane to higher hydrocarbons has also been studied. After a brief introduction to the concept of “the methanol economy” in the first chapter, the second...... chapter is a literature study of Mobil’s “methanol to hydrocarbons” (MTH) process, giving an overview of the history of the process, the nature of the employed catalysts, and the reaction mechanism. In the third chapter, a series of experiments concerning co conversion of ethane and methanol over...... a commercial H-ZSM-5 zeolite impregnated with gallium and/or molybdenum is described. The object was to investigate if the presence of methanol in the feed could enhance the conversion of ethane, but in all cases the opposite is observed; the presence of methanol actually suppresses the conversion of ethane...

  5. Multistep enzyme catalyzed reactions for unnatural amino acids.

    Science.gov (United States)

    D'Arrigo, Paola; Tessaro, Davide

    2012-01-01

    The use of unnatural amino acids, particularly synthetic α-amino acids, for modern drug discovery research requires the availability of enantiomerically pure isomers. Starting from a racemate, one single enantiomer can be obtained using a deracemization process. The two more common strategies of deracemization are those obtained by stereoinversion and by dynamic kinetic resolution. Both techniques will be here described using as a substrate the D,L-3-(2-naphthyl)-alanine, a non-natural amino acid: the first one employing a multi-enzymatic redox system, the second one combining an hydrolytic enzyme together with a base-catalyzed substrate racemization. In both cases, the final product, L-3-(2-naphthyl)alanine, is recovered with good yield and excellent enantiomeric excess.

  6. Palladium-catalyzed anti-Markovnikov oxidation of terminal alkenes.

    Science.gov (United States)

    Dong, Jia Jia; Browne, Wesley R; Feringa, Ben L

    2015-01-12

    The palladium-catalyzed oxidation of alkenes, the Wacker-Tsuji reaction, is undoubtedly a classic in organic synthesis and provides reliable access to methyl ketones from terminal alkenes under mild reaction conditions. Methods that switch the selectivity of the reaction to provide the aldehyde product are desirable because of the access they provide to a valuable functional group, however such methods are elusive. Herein we survey both the methods which have been developed recently in achieving such selectivity and discuss common features and mechanistic insight which offers promise in achieving the goal of a general method for anti-Markovnikov-selective olefin oxidations. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. WILDCAT: a catalyzed D-D tokamak reactor

    Energy Technology Data Exchange (ETDEWEB)

    Evans, K. Jr.; Baker, C.C.; Brooks, J.N.

    1981-11-01

    WILDCAT is a conceptual design of a catalyzed D-D, tokamak, commercial, fusion reactor. WILDCAT utilizes the beneficial features of no tritium breeding, while not extrapolating unnecessarily from existing D-T designs. The reactor is larger and has higher magnetic fields and plasma pressures than typical D-T devices. It is more costly, but eliminates problems associated with tritium breeding and has tritium inventories and throughputs approximately two orders of magnitude less than typical D-T reactors. There are both a steady-state version with Alfven-wave current drive and a pulsed version. Extensive comparison with D-T devices has been made, and cost and safety analyses have been included. All of the major reactor systems have been worked out to a level of detail appropriate to a complete, conceptual design.

  8. Cobalt catalyzed hydroesterification of a wide range of olefins

    Energy Technology Data Exchange (ETDEWEB)

    Van Rensburg, H.; Hanton, M.; Tooze, R.P.; Foster, D.F. [Sasol Technology UK, St Andrews (United Kingdom)

    2011-07-01

    Petrochemical raw materials are an essential raw material for the production of detergents with a substantial portion of synthetic fatty alcohols being produced via hydroformylation of oil or coal derived olefins. Carbonylation processes other than hydroformylation have to date not been commercially employed for the production of fatty esters or alcohols. In this document we highlight the opportunities of converting olefins to esters using cobalt catalyzed alkoxycarbonylation. This process is highly versatile and applicable to a wide range of olefins, linear or branched, alpha or internal in combination with virtually any chain length primary or secondary alcohol allowing the synthesis of a diverse array of compounds such as ester ethoxylated surfactants, methyl branched detergents, lubricants and alkyl propanoates. Furthermore, alkoxycarbonylation of a broad olefin/paraffin hydrocarbon range could be used to produce the corresponding broad cut detergent alcohols. (orig.)

  9. Mg-catalyzed autoclave synthesis of aligned silicon carbide nanostructures.

    Science.gov (United States)

    Xi, Guangcheng; Liu, Yankuan; Liu, Xiaoyan; Wang, Xiaoqing; Qian, Yitai

    2006-07-27

    In this article, a novel magnesium-catalyzed co-reduction route was developed for the large-scale synthesis of aligned beta-SiC one-dimensional (1D) nanostructures at relative lower temperature (600 degrees C). By carefully controlling the reagent concentrations, we could synthesize beta-SiC rodlike and needlelike nanostructures. The possible growth mechanism of the as-synthesized beta-SiC 1D nanostructures has been investigated. The structure and morphology of the as-synthesized beta-SiC nanostructures are characterized using X-ray diffraction, Fourier transform infrared absorption, and scanning and transmission electron microscopes. Raman and photoluminescence properties are also investigated at room temperature. The as-synthesized beta-SiC nanostructures exhibit strong shape-dependent field emission properties. Corresponding to their shapes, the as-synthesized nanorods and nanoneedles display the turn-on fields of 12, 8.4, and 1.8 V/microm, respectively.

  10. Specific miRNA Stabilization by Gld2-Catalyzed Monoadenylation

    Directory of Open Access Journals (Sweden)

    Andrea D’Ambrogio

    2012-12-01

    Full Text Available MicroRNAs (miRNAs are small, noncoding RNAs that inhibit translation and promote mRNA decay. The levels of mature miRNAs are the result of different rates of transcription, processing, and turnover. The noncanonical polymerase Gld2 has been implicated in the stabilization of miR-122, possibly through catalyzing 3′ monoadenylation; however, there is little evidence that this relationship is one of cause and effect. Here, we biochemically characterize Gld2’s involvement in miRNA monoadenylation and its effect on miRNA stability. We find that Gld2 directly monoadenylates and stabilizes specific miRNA populations in human fibroblasts and that sensitivity to monoadenylation-induced stability depends on nucleotides in the miRNA 3′ end. These results establish a mechanism of miRNA stability and resulting posttranscriptional gene regulation.

  11. Rhenium-catalyzed deoxydehydration of diols and polyols.

    Science.gov (United States)

    Dethlefsen, Johannes R; Fristrup, Peter

    2015-03-01

    The substitution of platform chemicals of fossil origin by biomass-derived analogues requires the development of chemical transformations capable of reducing the very high oxygen content of biomass. One such reaction, which has received increasing attention within the past five years, is the rhenium-catalyzed deoxydehydration (DODH) of a vicinal diol into an alkene; this is a model system for abundant polyols like glycerol and sugar alcohols. The present contribution includes a review of early investigations of stoichiometric reactions involving rhenium, diols, and alkenes followed by a discussion of the various catalytic systems that have been developed with emphasis on the nature of the reductant, the substrate scope, and mechanistic investigations. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Manganese-Catalyzed Upgrading of Ethanol into 1-Butanol.

    Science.gov (United States)

    Fu, Shaomin; Shao, Zhihui; Wang, Yujie; Liu, Qiang

    2017-08-30

    Biomass-derived ethanol is an important renewable feedstock. Its conversion into high-quality biofuels is a promising route to replace fossil resources. Herein, an efficient manganese-catalyzed Guerbet-type condensation reaction of ethanol to form 1-butanol was explored. This is the first example of upgrading ethanol into higher alcohols using a homogeneous non-noble-metal catalyst. This process proceeded selectively in the presence of a well-defined manganese pincer complex at the parts per million (ppm) level. The developed reaction represents a sustainable synthesis of 1-butanol with excellent turnover number (>110 000) and turnover frequency (>3000 h(-1)). Moreover, mechanistic studies including control experiments, NMR spectroscopy, and X-ray crystallography identified the essential role of the "N-H moiety" of the manganese catalysts and the major reaction intermediates related to the catalytic cycle.

  13. Calcium-catalyzed pyrolysis of lignocellulosic biomass components.

    Science.gov (United States)

    Case, Paige A; Truong, Chi; Wheeler, M Clayton; DeSisto, William J

    2015-09-01

    The present study examines the effect of calcium pretreatment on pyrolysis of individual lignocellulosic compounds. Previous work has demonstrated that the incorporation of calcium compounds with the feedstock prior to pyrolysis has a significant effect on the oxygen content and stability of the resulting oil. The aim of this work was to further explore the chemistry of calcium-catalyzed pyrolysis. Bench-scale pyrolysis of biomass constituents, including lignin, cellulose and xylan is performed and compared to the oils produced from pyrolysis of the same components after calcium pretreatment. The resulting oils were analyzed by quantitative GC-MS and SEC. These analyses, together with data collected from previous work provide evidence which was used to develop proposed reaction pathways for pyrolysis of calcium-pretreatment biomass. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Lactam hydrolysis catalyzed by mononuclear metallo-ß-bactamases

    DEFF Research Database (Denmark)

    Olsen, Lars; Antony, J; Ryde, U

    2003-01-01

    Two central steps in the hydrolysis of lactam antibiotics catalyzed by mononuclear metallo-beta-lactamases, formation of the tetrahedral intermediate and its breakdown by proton transfer, are studied for model systems using the density functional B3LYP method. Metallo-beta-lactamases have two metal...... coordinating to the zinc ion. Potential proton shuttles from the second (unoccupied) metal-binding site (water, Asp, or Cys) are included in some calculations. The calculated reaction barrier for formation of the tetrahedral intermediate is 13 kcal/mol, close to what is observed experimentally for the rate......-limiting step. The barrier for the breakdown of the intermediate is low, 0-10 kcal/mol, if it is assisted by a water molecule or by a Cys or Asp model. Thus, the results indicate that proton transfer is not rate-limiting, and that any of the residues from the second metal site may function as proton shuttle...

  15. Manganese-Catalyzed Aerobic Heterocoupling of Aryl Grignard Reagents

    DEFF Research Database (Denmark)

    Ghaleshahi, Hajar Golshahi; Antonacci, Giuseppe; Madsen, Robert

    2017-01-01

    An improved protocol has been developed for the MnCl2-catalyzed cross-coupling reaction of two arylmagnesium bromides under dioxygen. The reaction was achieved by using the Grignard reagents in a 2:1 ratio and 20 % of MnCl2. Very good yields of the heterocoupling product were obtained when...... the limiting Grignard reagent underwent little homocoupling under the reaction conditions. Arylmagnesium bromides that contain p-methoxy, p-(dimethylamino), p-fluoro, and p-chloro substituents were shown to afford high product yields in the cross-coupling reactions with a variety of substituted aryl Grignard...... reagents. Heterocyclic Grignard reagents, on the other hand, were less effective substrates for this transformation because of the rapid homocoupling of these reagents under the reaction conditions....

  16. Quinone-Catalyzed Selective Oxidation of Organic Molecules.

    Science.gov (United States)

    Wendlandt, Alison E; Stahl, Shannon S

    2015-12-01

    Quinones are common stoichiometric reagents in organic chemistry. Para-quinones with high reduction potentials, such as DDQ and chloranil, are widely used and typically promote hydride abstraction. In recent years, many catalytic applications of these methods have been achieved by using transition metals, electrochemistry, or O2 to regenerate the oxidized quinone in situ. Complementary studies have led to the development of a different class of quinones that resemble the ortho-quinone cofactors in copper amine oxidases and mediate the efficient and selective aerobic and/or electrochemical dehydrogenation of amines. The latter reactions typically proceed by electrophilic transamination and/or addition-elimination reaction mechanisms, rather than hydride abstraction pathways. The collective observations show that the quinone structure has a significant influence on the reaction mechanism and has important implications for the development of new quinone reagents and quinone-catalyzed transformations. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. FBH1 Catalyzes Regression of Stalled Replication Forks

    Directory of Open Access Journals (Sweden)

    Kasper Fugger

    2015-03-01

    Full Text Available DNA replication fork perturbation is a major challenge to the maintenance of genome integrity. It has been suggested that processing of stalled forks might involve fork regression, in which the fork reverses and the two nascent DNA strands anneal. Here, we show that FBH1 catalyzes regression of a model replication fork in vitro and promotes fork regression in vivo in response to replication perturbation. Cells respond to fork stalling by activating checkpoint responses requiring signaling through stress-activated protein kinases. Importantly, we show that FBH1, through its helicase activity, is required for early phosphorylation of ATM substrates such as CHK2 and CtIP as well as hyperphosphorylation of RPA. These phosphorylations occur prior to apparent DNA double-strand break formation. Furthermore, FBH1-dependent signaling promotes checkpoint control and preserves genome integrity. We propose a model whereby FBH1 promotes early checkpoint signaling by remodeling of stalled DNA replication forks.

  18. Enantioselective aldol reactions catalyzed by chiral phosphine oxides.

    Science.gov (United States)

    Kotani, Shunsuke; Sugiura, Masaharu; Nakajima, Makoto

    2013-08-01

    The development of enantioselective aldol reactions catalyzed by chiral phosphine oxides is described. The aldol reactions presented herein do not require the prior preparation of the masked enol ethers from carbonyl compounds as aldol donors. The reactions proceed through a trichlorosilyl enol ether intermediate, formed in situ from carbonyl compounds, which then acts as the aldol donor. Phosphine oxides activate the trichlorosilyl enol ethers to afford the aldol adducts with high stereoselectivities. This procedure was used to realize a directed cross-aldol reaction between ketones and two types of double aldol reactions (a reaction at one/two α position(s) of a carbonyl group) with high diastereo- and enantioselectivities. Copyright © 2013 The Chemical Society of Japan and Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Urea- and Thiourea-Catalyzed Aminolysis of Carbonates.

    Science.gov (United States)

    Blain, Marine; Yau, Honman; Jean-Gérard, Ludivine; Auvergne, Rémi; Benazet, Dominique; Schreiner, Peter R; Caillol, Sylvain; Andrioletti, Bruno

    2016-08-23

    The aminolysis of (poly)carbonates by (poly)amines provides access to non-isocyanate polyurethanes (NIPUs) that are toxic-reagent-free analogues of polyurethanes (PUs). Owing to their low reactivity, the ring opening of cyclic carbonates requires the use of a catalyst. Herein, we report that the more available and cheaper ureas could advantageously be used for catalyzing the formation of NIPUs at the expense of the thiourea analogues. In addition, we demonstrate a medium-range pKa of the (thio)urea and an unqeual substitution pattern is critical for controlling the efficiency of the carbonate opening. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Vanadium bromoperoxidase-catalyzed biosynthesis of halogenated marine natural products.

    Science.gov (United States)

    Carter-Franklin, Jayme N; Butler, Alison

    2004-11-24

    Marine red algae (Rhodophyta) are a rich source of bioactive halogenated natural products. The biogenesis of the cyclic halogenated terpene marine natural products, in particular, has attracted sustained interest in part because terpenes are the biogenic precursors of many bioactive metabolites. The first enzymatic asymmetric bromination and cyclization of a terpene, producing marine natural products isolated from red algae, is reported. Vanadium bromoperoxidase (V-BrPO) isolated from marine red algae (species of Laurencia, Plocamium, Corallina) catalyzes the bromination of the sesquiterpene (E)-(+)-nerolidol producing alpha-, beta-, and gamma-snyderol and (+)-3beta-bromo-8-epicaparrapi oxide. alpha-Snyderol, beta-snyderol, and (+)-3beta-bromo-8-epicaparrapi oxide have been isolated from Laurencia obtusa, and each have also been isolated from other species of marine red algae. gamma-Snyderol is a proposed intermediate in other bicyclo natural products. Single diastereomers of beta-snyderol, gamma-snyderol, and mixed diastereomers of (+)-3beta-bromo-8-epicaparrapi oxide (de = 20-25%) are produced in the enzyme reaction, whereas two diastereomers of these compounds are formed in the synthesis with 2,4,4,6-tetrabromocyclohexa-2,5-dienone (TBCO). V-BrPO likely functions by catalyzing the two-electron oxidation of bromide ion by hydrogen peroxide producing a bromonium ion or equivalent in the active site that brominates one face of the terminal olefin of nerolidol. These results establish V-BrPO's role in the biosynthesis of brominated cyclic sesquiterpene structures from marine red algae for the first time.