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Sample records for pyrones

  1. Bis-naphtho-γ-pyrones from Fungi and Their Bioactivities

    Directory of Open Access Journals (Sweden)

    Shiqiong Lu

    2014-05-01

    Full Text Available Bis-naphtho-γ-pyrones are an important group of aromatic polyketides derived from fungi. They have a variety of biological activities including cytotoxic, antitumor, antimicrobial, tyrosine kinase and HIV-1 integrase inhibition properties, demonstrating their potential applications in medicine and agriculture. At least 59 bis-naphtho-γ-pyrones from fungi have been reported in the past few decades. This mini-review aims to briefly summarize their occurrence, biosynthesis, and structure, as well as their biological activities. Some considerations regarding to synthesis, production, and medicinal and agricultural applications of bis-naphtho-γ-pyrones are also discussed.

  2. Recent Advances in the Synthesis of 2-Pyrones

    Directory of Open Access Journals (Sweden)

    Jong Seok Lee

    2015-03-01

    Full Text Available The present review summarizes the recent progresses in the synthesis of 2-pyrones and the application to the synthesis of marine natural products. Especially, much attention was placed on the transition metal catalyzed synthetic methodologies in this review.

  3. PYRONES: pyro-modeling and evacuation simulation system

    Science.gov (United States)

    Kanellos, Tassos; Doulgerakis, Adam; Georgiou, Eftichia; Kountouriotis, Vassilios I.; Paterakis, Manolis; Thomopoulos, Stelios C. A.; Pappou, Theodora; Vrahliotis, Socrates I.; Rekouniotis, Thrasos; Protopsaltis, Byron; Rozenberg, Ofir; Livneh, Ofer

    2016-05-01

    Structural fires continue to pose a great threat towards human life and property. Due to the complexity and non-deterministic characteristics of a building fire disaster, it is not a straightforward task to assess the effectiveness of fire protection measures embedded in the building design, planned evacuation strategies and potential modes of response for mitigating the fire's consequences. Additionally, there is a lack of means that realistically and accurately recreate the conditions of building fire disasters for the purpose of training personnel in order to be sufficiently prepared when vis-a-vis with such an environment. The propagation of fire within a building, the diffusion of its volatile products, the behavior of the occupants and the sustained injuries not only exhibit non-linear behaviors as individual phenomena, but are also intertwined in a web of co-dependencies. The PYRONES system has been developed to address all these aspects through a comprehensive approach that relies on accurate and realistic computer simulations of the individual phenomena and their interactions. PYRONES offers innovative tools and services to strategically targeted niches in two market domains. In the domain of building design and engineering, PYRONES is seamlessly integrated within existing engineering Building Information Modelling (BIM) workflows and serves as a building performance assessment platform, able to evaluate fire protection systems. On another front, PYRONES penetrates the building security management market, serving as a holistic training platform for specialists in evacuation strategy planning, firefighters and first responders, both at a Command and Control and at an individual trainee level.

  4. A New Pyrone Derivative from Fungus Cephalosporium sp. AL031

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A novel pyrone derivative was isolated from the ethyl acetate extract of a culture broth of a strain of the fungus Cephalosporium sp. AL031. Its structure was characterized as 7-hydroxy-9-methoxyl-10-methyl-2H, 4aH, 6H, 10bH-pyrano[5, 6-c][2]benzopyran-2, 6-dione by spectroscopic analysis including IR, MS, 1D and 2D NMR spectra.

  5. Synthesis, characterization and photophysical studies of -triazolomethyl-bridged porphyrin-benzo--pyrone dyads

    Indian Academy of Sciences (India)

    Dileep Kumar Singh; Mahendra Nath

    2016-04-01

    A new series of zinc(II) -triazolomethyl-bridged porphyrin-benzo--pyrone dyads have been synthesized in appreciable yields through a copper(I)-catalyzed “click” reaction of zinc(II) 2-azidomethyl-5,10,15,20-tetraphenylporphyrin with various benzo--pyronoalkynes. These novel zinc(II) porphyrin-benzo--pyrone dyads successfully underwent demetallation in the presence of concentrated hydrochloric acid in chloroform at 25°C to form the corresponding free-base porphyrin analogues in good yields. The newly synthesized products were characterized on the basis of spectral data and evaluated for their electronic absorption and fluorescence properties. Some of these molecules have shown a significant intramolecular energy transfer between the benzo--pyrone and porphyrin subunits.

  6. Response of Substituted Indoleacetic Acids in the Indolo-alpha-pyrone Fluorescence Determination

    DEFF Research Database (Denmark)

    Engvild, Kjeld Christensen; Böttger, M.; Kaiser, P.

    1978-01-01

    .-pyrones. Other halogenated indoleacetic acids show between zero and 60% of the fluorescence of IAA. Apparently the concentration of IAA cannot be determined in crude extracts in the presence of 4-chloro- or 5-hydroxy-indoleacetic acid, because separate determinations of each of these compounds are not possible......The method of indolo-.alpha.-pyrone fluorescence-determination of IAA was investigated to study possible interference from 4-chloro-indoleacetic acid and 5-hydroxyindoleacetic acid, which occur naturally. Both compounds show about 40% of the fluorescence of IAA after conversion into their .alpha...

  7. Two new alpha-pyrones and other components from the cladodes of Opuntia dillenii.

    Science.gov (United States)

    Qiu, Ying Kun; Zhao, Yan Yan; Dou, De Qiang; Xu, Bi Xia; Liu, Ke

    2007-06-01

    The aqueous ethanolic extract from the fresh cladodes of Opuntia dillenii HAW. was found to show anti-inflammatory activity. Two new alpha-pyrones, named opuntioside II (1) and opuntioside III (2), were isolated from the extract together with six known compounds. The structures of the new compounds were determined on the basis of chemical and physicochemical evidence.

  8. 1, 4-Pyrone Effects on O-H Bond Dissociation Energies of Catechols in Flavonoids: A Density Functional Theory Study

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Through B3LYP/6-31G** calculations, the 1, 4-pyrone effects on O-H bond dissociation energies (BDEs) of catechols in rings A or B of flavonoids were investigated. For the catechol in ring A, although 1, 4-pyrone enlarged the conjugation system, its electron-withdrawing property increased the O-H BDE 3 ( 4.184 kJ/mol compared with that of catechol. However, for the catechol in ring B, 1, 4-pyrone was poorly conjugated with the moiety, and therefore, had little effect on the O-H BDE.

  9. Ruthenium-catalyzed decarbonylative addition reaction of anhydrides with alkynes: a facile synthesis of isocoumarins and α-pyrones.

    Science.gov (United States)

    Prakash, Rashmi; Shekarrao, Kommuri; Gogoi, Sanjib; Boruah, Romesh C

    2015-06-21

    A novel ruthenium catalyzed straightforward and efficient synthesis of isocoumarin and α-pyrone derivatives has been accomplished by the decarbonylative addition reaction of anhydrides with alkynes under thermal conditions.

  10. Advanced mutasynthesis studies on the natural α-pyrone antibiotic myxopyronin from Myxococcus fulvus.

    Science.gov (United States)

    Sahner, J Henning; Sucipto, Hilda; Wenzel, Silke C; Groh, Matthias; Hartmann, Rolf W; Müller, Rolf

    2015-04-13

    Myxopyronin is a natural α-pyrone antibiotic from the soil bacterium Myxococcus fulvus Mx f50. Myxopyronin inhibits bacterial RNA polymerase (RNAP) by binding to a part of the enzyme not targeted by the clinically used rifamycins. This mode of action makes myxopyronins promising molecules for the development of novel broad-spectrum antibacterials. We describe the derivatization of myxopyronins by an advanced mutasynthesis approach as a first step towards this goal. Site-directed mutagenesis of the biosynthetic machinery was used to block myxopyronin biosynthesis at different stages. The resulting mutants were fed with diverse precursors that mimic the biosynthetic intermediates to restore production. Mutasynthon incorporation and production of novel myxopyronin derivatives were analyzed by HPLC-MS/MS. This work sets the stage for accessing numerous myxopyronin derivatives, thus significantly expanding the chemical space of f α-pyrone antibiotics. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Synthesis and biological evaluation of 3-amino-2-pyrones as selective cyclooxygenase-1 (COX-1) inhibitors

    Institute of Scientific and Technical Information of China (English)

    Xue-Ping Chu; Qing-Fa Zhou; Shen Zhao; Fei-Fei Ge; Mian Fu; Jia-Peng Chen; Tao Lu

    2013-01-01

    A group of 3-amino-2-pyrones were synthesized and their biological activities were evaluated for inhibiting cyclooxygenase (COX) activity.This study has led to the identification of COX-1-selective inhibitors.Among the tested compounds,the compound 5j exhibited the most potent COX-1 inhibitory activity (IC50 =19.32 μg/mL) and COX-1 selectivity index (SI =41.98).

  12. Fungal naphtho-γ-pyrones: Potent antibiotics for drug-resistant microbial pathogens

    OpenAIRE

    Yan He; Jun Tian; Xintao Chen; Weiguang Sun; Hucheng Zhu; Qin Li; Liang Lei; Guangmin Yao; Yongbo Xue; Jianping Wang; Hua Li; Yonghui Zhang

    2016-01-01

    Four naphtho-γ-pyrones (fonsecinones A and C and aurasperones A and E) were identified as potential antibacterial agents against Escherichia coli, extended-spectrum β-lactamase (ESBL)-producing E. coli, Pseudomonas aeruginosa, Enterococcus faecalis, and methicillin-resistant Staphylococcus aureus (MRSA) in an in vitro antibacterial screen of 218 fungal metabolites. Fonsecinone A (2) exhibited the most potent antibacterial activity, with minimum inhibitory concentrations (MICs) of 4.26, 17.04,...

  13. Fungal naphtho-γ-pyrones: Potent antibiotics for drug-resistant microbial pathogens.

    Science.gov (United States)

    He, Yan; Tian, Jun; Chen, Xintao; Sun, Weiguang; Zhu, Hucheng; Li, Qin; Lei, Liang; Yao, Guangmin; Xue, Yongbo; Wang, Jianping; Li, Hua; Zhang, Yonghui

    2016-04-11

    Four naphtho-γ-pyrones (fonsecinones A and C and aurasperones A and E) were identified as potential antibacterial agents against Escherichia coli, extended-spectrum β-lactamase (ESBL)-producing E. coli, Pseudomonas aeruginosa, Enterococcus faecalis, and methicillin-resistant Staphylococcus aureus (MRSA) in an in vitro antibacterial screen of 218 fungal metabolites. Fonsecinone A (2) exhibited the most potent antibacterial activity, with minimum inhibitory concentrations (MICs) of 4.26, 17.04, and 4.26 μg/mL against ESBL-producing E. coli, P. aeruginosa, and E. faecalis, respectively. The inhibitory effects of fonsecinones A (2) and C (3) against E. coli and ESBL-producing E. coli were comparable to those of amikacin. Molecular docking-based target identification of naphtho-γ-pyrones 1-8 revealed bacterial enoyl-acyl carrier protein reductase (FabI) as an antibacterial target, which was further validated by FabI affinity and inhibition assays. Fonsecinones A (2) and C (3) and aurasperones A (6) and E (7) bound FabI specifically and produced concentration-dependent inhibition effects. This work is the first report of anti-drug-resistant bacterial activities of naphtho-γ-pyrones 1-8 and their possible antibacterial mechanism of action and provides an example of the successful application of in silico methods for drug target identification and validation and the identification of new lead antibiotic compounds against drug-resistant pathogens.

  14. Structure-based design of HIV protease inhibitors: 5,6-dihydro-4-hydroxy-2-pyrones as effective, nonpeptidic inhibitors.

    Science.gov (United States)

    Thaisrivongs, S; Romero, D L; Tommasi, R A; Janakiraman, M N; Strohbach, J W; Turner, S R; Biles, C; Morge, R R; Johnson, P D; Aristoff, P A; Tomich, P K; Lynn, J C; Horng, M M; Chong, K T; Hinshaw, R R; Howe, W J; Finzel, B C; Watenpaugh, K D

    1996-11-08

    From a broad screening program, the 4-hydroxycoumarin phenprocoumon (I) was previously identified as a lead template with HIV protease inhibitory activity. The crystal structure of phenprocoumon/HIV protease complex initiated a structure-based design effort that initially identified the 4-hydroxy-2-pyrone U-96988 (II) as a first-generation clinical candidate for the potential treatment of HIV infection. Based upon the crystal structure of the 4-hydroxy-2-pyrone III/HIV protease complex, a series of analogues incorporating a 5,6-dihydro-4-hydroxy-2-pyrone template were studied. It was recognized that in addition to having the required pharmacophore (the 4-hydroxy group with hydrogen-bonding interaction with the two catalytic aspartic acid residues and the lactone moiety replacing the ubiquitous water molecule in the active site), these 5,6-dihydro-4-hydroxy-2-pyrones incorporated side chains at the C-6 position that appropriately extended into the S1' and S2' subsites of the enzyme active site. The crystal structures of a number of representative 5,6-dihydro-4-hydroxy-2-pyrones complexed with the HIV protease were also determined to provide better understanding of the interaction between the enzyme and these inhibitors to aid the structure-based drug design effort. The crystal structures of the ligands in the enzyme active site did not always agree with the conformations expected from experience with previous pyrone inhibitors. This is likely due to the increased flexibility of the dihydropyrone ring. From this study, compound XIX exhibited reasonably high enzyme inhibitory activity (Ki = 15 nM) and showed antiviral activity (IC50 = 5 microM) in the cell-culture assay. This result provided a research direction which led to the discovery of active 5,6-dihydro-4-hydroxy-2-pyrones as potential agents for the treatment of HIV infection.

  15. Gombapyrones E and F, New α-Pyrone Polyenes Produced by Streptomyces sp. KMC-002

    Directory of Open Access Journals (Sweden)

    Kang Ro Lee

    2011-04-01

    Full Text Available Microorganism-derived polyene polyketides have been shown to display a variety of biological activities and have attracted great interest due to their structurally intriguing chemical diversity. Two new polyenes were isolated from a culture broth of Streptomyces sp. KMC-002 obtained from a soil sample in an abandoned mine. The structures of these compounds were determined to be α-pyrone-containing polyene analogues through analyses of HRFABMS, UV and NMR data, and were named Gombapyrones E (1 and F (2. Gombapyrone E (1 showed antibacterial activity against Micrococcus luteus, Enterococcus hirae, Staphylococcus aureus and MRSA.

  16. Constituents with radical scavenging effect from Opuntia dillenii: structures of new alpha-pyrones and flavonol glycoside.

    Science.gov (United States)

    Qiu, Yingkun; Chen, Yingjie; Pei, Yupin; Matsuda, Hisashi; Yoshikawa, Masayuki

    2002-11-01

    The aqueous ethanolic extract from the fresh stems of Opuntia dillenii HAW. showed potent radical scanvenging activity. Three new compounds, opuntioside I, 4-ethoxyl-6-hydroxymethyl-alpha-pyrone, and kaempferol 7-O-beta-D-glucopyranosyl-(1-->4)-beta-D-glucopyranoside, were isolated from the extract. The structures of the new compounds were determined on the basis of chemical and physicochemical evidence and the radical scavenging effects of principal constituents were examined.

  17. Inhibition of Alzheimer's amyloid toxicity with a tricyclic pyrone molecule in vitro and in vivo.

    Science.gov (United States)

    Hong, Hyun-Seok; Rana, Sandeep; Barrigan, Lydia; Shi, Aibin; Zhang, Yi; Zhou, Feimeng; Jin, Lee-Way; Hua, Duy H

    2009-02-01

    Small beta-amyloid (Abeta) 1-42 aggregates are toxic to neurons and may be the primary toxic species in Alzheimer's disease (AD). Methods to reduce the level of Abeta, prevent Abeta aggregation, and eliminate existing Abeta aggregates have been proposed for treatment of AD. A tricyclic pyrone named CP2 is found to prevent cell death associated with Abeta oligomers. We studied the possible mechanisms of neuroprotection by CP2. Surface plasmon resonance spectroscopy shows a direct binding of CP2 with Abeta42 oligomer. Circular dichroism spectroscopy reveals monomeric Abeta42 peptide remains as a random coil/alpha-helix structure in the presence of CP2 over 48 h. Atomic force microscopy studies show CP2 exhibits similar ability to inhibit Abeta42 aggregation as that of Congo red and curcumin. Atomic force microscopy closed-fluid cell study demonstrates that CP2 disaggregates Abeta42 oligomers and protofibrils. CP2 also blocks Abeta fibrillations using a protein quantification method. Treatment of 5x familial Alzheimer's disease mice, a robust Abeta42-producing animal model of AD, with a 2-week course of CP2 resulted in 40% and 50% decreases in non-fibrillar and fibrillar Abeta species, respectively. Our results suggest that CP2 might be beneficial to AD patients by preventing Abeta aggregation and disaggregating existing Abeta oligomers and protofibrils.

  18. Characterization of a polyketide synthase in Aspergillus niger whose product is a precursor for both dihydroxynaphthalene (DHN) melanin and naphtho-γ-pyrone.

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, Yi Ming; Meyer, Kristen M; Praseuth, Michael; Baker, Scott E; Bruno, Kenneth S; Wang, Clay C

    2010-12-06

    The genome sequencing of the fungus Aspergillus niger, an industrial workhorse, uncovered a large cache of genes encoding enzymes thought to be involved in the production of secondary metabolites yet to be identified. Identification and structural characterization of many of these predicted secondary metabolites are hampered by their low concentration relative to the known A. niger metabolites such as the naphtho-γ-pyrone family of polyketides. We deleted a nonreducing PKS gene in A. niger strain ATCC 11414, a daughter strain of A. niger ATCC strain 1015 whose genome was sequenced by the DOE Joint Genome Institute. This PKS encoding gene is a predicted ortholog of alb1 from Aspergillus fumigatus which is responsible for production of YWA1, a precursor of fungal DHN melanin. Our results show that the A. niger alb1 PKS is responsible for the production of the polyketide precursor for DHN melanin biosynthesis. Deletion of alb1 elimnates the production of major metabolites, naphtho-γ-pyrones. The generation of an A. niger strain devoid of naphtho-γ-pyrones will greatly facilitate the elucidation of cryptic biosynthetic pathways in this organism.

  19. Tricyclic pyrone compounds prevent aggregation and reverse cellular phenotypes caused by expression of mutant huntingtin protein in striatal neurons

    Directory of Open Access Journals (Sweden)

    McMurray Cynthia T

    2009-07-01

    Full Text Available Abstract Background Huntington's disease (HD is a progressive neurodegenerative disorder caused by a CAG repeat expansion mutation in the coding region of a novel gene. The mechanism of HD is unknown. Most data suggest that polyglutamine-mediated aggregation associated with expression of mutant huntingtin protein (mhtt contributes to the pathology. However, recent studies have identified early cellular dysfunctions that preclude aggregate formation. Suppression of aggregation is accepted as one of the markers of successful therapeutic approaches. Previously, we demonstrated that tricyclic pyrone (TP compounds efficiently inhibited formation of amyloid-β (Aβ aggregates in cell and mouse models representing Alzheimer's Disease (AD. In the present study, we aimed to determine whether TP compounds could prevent aggregation and restore early cellular defects in primary embryonic striatal neurons from animal model representing HD. Results TP compounds effectively inhibit aggregation caused by mhtt in neurons and glial cells. Treatment with TP compounds also alleviated cholesterol accumulation and restored clathrin-independent endocytosis in HD neurons. Conclusion We have found that TP compounds not only blocked mhtt-induced aggregation, but also alleviated early cellular dysfunctions that preclude aggregate formation. Our data suggest TP molecules may be used as lead compounds for prevention or treatment of multiple neurodegenerative diseases including HD and AD.

  20. Pd/C-mediated synthesis of α-pyrone fused with a five-membered nitrogen heteroaryl ring: A new route to pyrano[4,3-c]pyrazol-4(1H-ones

    Directory of Open Access Journals (Sweden)

    Dhilli Rao Gorja

    2009-11-01

    Full Text Available Pd/C-mediated alkynylation of 5-iodo-pyrazole-4-carboxylic acid, involving the first regioselective construction of α-pyrone ring on a pyrazol moiety via tandem coupling–cyclization process, has been developed to afford pyrano[4,3-c]pyrazol-4(1H-one in a single pot.

  1. Synthesis of 6-Substituted 2-Pyrones Starting from Renewable Resources: Total Synthesis of Sibirinone, (E)-6-(Pent-1-en-1-yl)-2H-pyran-2-one, and (E)-6-(Hept-1-en-1-yl)-2H-pyran-2-one.

    Science.gov (United States)

    Dobler, Daniel; Reiser, Oliver

    2016-11-04

    An atom-economic reaction sequence to 6-substituted 2-pyrones was developed starting from furfuryl alcohol, a renewable resource made from bran or bagasse, and aldehydes, utilizing a thermal rearrangement of cyclopentadienone epoxides as key step. Derivatives bearing a hydroxyalkyl side chain could be enzymatically resolved, providing access to enantiomerically pure 2-pyrones, or converted to alkenyl-substituted 2-pyrones such as naturally occurring sibirinone, (E)-6-(pent-1-en-1-yl)-2H-pyran-2-one, and (E)-6-(hept-1-en-1-yl)-2H-pyran-2-one.

  2. Tipranavir (PNU-140690): a potent, orally bioavailable nonpeptidic HIV protease inhibitor of the 5,6-dihydro-4-hydroxy-2-pyrone sulfonamide class.

    Science.gov (United States)

    Turner, S R; Strohbach, J W; Tommasi, R A; Aristoff, P A; Johnson, P D; Skulnick, H I; Dolak, L A; Seest, E P; Tomich, P K; Bohanon, M J; Horng, M M; Lynn, J C; Chong, K T; Hinshaw, R R; Watenpaugh, K D; Janakiraman, M N; Thaisrivongs, S

    1998-08-27

    A broad screening program previously identified phenprocoumon (1) as a small molecule template for inhibition of HIV protease. Subsequent modification of this lead through iterative cycles of structure-based design led to the activity enhancements of pyrone and dihydropyrone ring systems (II and V) and amide-based substitution (III). Incorporation of sulfonamide substitution within the dihydropyrone template provided a series of highly potent HIV protease inhibitors, with structure-activity relationships described in this paper. Crystallographic studies provided further information on important binding interactions responsible for high enzymatic binding. These studies culminated in compound VI, which inhibits HIV protease with a Ki value of 8 pM and shows an IC90 value of 100 nM in antiviral cell culture. Clinical trials of this compound (PNU-140690, Tipranavir) for treatment of HIV infection are currently underway.

  3. Asperpyrone-Type Bis-Naphtho-γ-Pyrones with COX-2–Inhibitory Activities from Marine-Derived Fungus Aspergillus niger

    Directory of Open Access Journals (Sweden)

    Wei Fang

    2016-07-01

    Full Text Available Bis-naphtho-γ-pyrones (BNPs are an important group of aromatic polyketides derived from fungi, and asperpyrone-type BNPs are produced primarily by Aspergillus species. The fungal strain Aspergillus niger SCSIO Jcsw6F30, isolated from a marine alga, Sargassum sp., and identified according to its morphological traits and the internal transcribed spacer (ITS region sequence, was studied for BNPs secondary metabolisms. After HPLC/MS analysis of crude extract of the fermentation broth, 11 asperpyrone-type BNPs were obtained directly and quickly by chromatographic separation in the extract, and those isolated asperpyrone-type BNPs were structurally identified by NMR and MS analyses. All of the BNPs showed weak cytotoxicities against 10 human tumor cells (IC50 > 30 μM. However, three of them, aurasperone F (3, aurasperone C (6 and asperpyrone A (8, exhibited obvious COX-2–inhibitory activities, with the IC50 values being 11.1, 4.2, and 6.4 μM, respectively. This is the first time the COX-2–inhibitory activities of BNPs have been reported.

  4. Penicyrones A and B, an epimeric pair of α-pyrone-type polyketides produced by the marine-derived Penicillium sp.

    Science.gov (United States)

    Bu, Ying-Yue; Yamazaki, Hiroyuki; Takahashi, Ohgi; Kirikoshi, Ryota; Ukai, Kazuyo; Namikoshi, Michio

    2016-01-01

    Two polyketides containing an α-pyrone unit, named penicyrones A (1) and B (2), were isolated from a culture broth of the marine-derived Penicillium sp. TPU1271 together with nine known compounds: verrucosidin (3), fructigenine A (4), verrucofortine (5), cyclo-(L-Trp-L-Phe) (6), cyclopenol (7), cyclopenin (8), penipratynolene (9), aspterric acid (10) and viridicatol (11). The structures of 1 and 2 were elucidated by analyzing the spectroscopic data of 1, 2 and their O-acetyl derivatives (1a and 2a). Compounds 1 and 2 were epimers of each other at the C-9 position. The absolute configurations of 1 and 2 were assigned on the basis of NOESY data for 1, 2, 1a and 2a, a conformational analysis and the identity of the biogenetic pathway with verrucosidin (3). The planar structure of penicyrones was found in the SciFinder as a compound in the commercial chemical libraries; however, the stereostructure and spectroscopic data were not available. Therefore, this is the first study on the isolation and structure elucidation, including the absolute configurations, of penicyrones A (1) and B (2) as fungal metabolites. Compound 3 exhibited growth inhibitory activity against Mycobacterium smegmatis at 40 μg per disc (inhibition zone of 11 mm). This is the first study to demonstrate that verrucosidin (3) exhibited anti-mycobacterial activity.

  5. One-step separation and purification of two chromones and one pyrone from Aloe barbadensis Miller: a comparison between reversed-phase flash chromatography and high-speed counter current chromatography.

    Science.gov (United States)

    Zhong, Jia-Sheng; Wan, Jin-Zhi; Ding, Wen-Jing; Wu, Xiao-Fang; Xie, Zhi-Yong

    2014-01-01

    Chromones and pyrones are the major secondary metabolites of Aloe barbadensis Miller. As they are minor components of the plant, an efficient purification procedure for them is of great importance for promoting their pharmacological studies. To develop efficient methods for one-step separation and purification of two chromones (5-((S)-2'-oxo-4'-hydroxypentyl)-2-hydroxymethylchromone (1) and 5-((4E)-2'-oxo-pentenyl)-2-hydroxymethylchromone (3)) and one pyrone (aloenin aglycone (2)) from A. barbadensis via reversed-phase flash chromatography (RP-FC) and high-speed counter current chromatography (HSCCC). The RP-FC separation was performed using methanol:water (26:74, v/v) as the mobile phase at a flow rate of 20 mL/min. A solvent system composed of dichloromethane:methanol:water (3:1.5:1, v/v/v) was used for the HSCCC separation, at a flow rate of 2.0 mL/min. A one-step RP-FC operation within 110 min was successfully used for the purification of compounds 1 (27.9 mg, 96.5%), 2 (32.4 mg, 98.2%) and 3 (4.1 mg, 99.0%) from 129 mg of crude sample, and a one-step HSCCC separation within 95 min was successfully implemented for the purification of compounds 1 (31.1 mg, 97.6%), 2 (35.8 mg, 96.7%) and 3 (2.7 mg, 98.1%) from 134 mg of crude sample. The developed procedures were efficient, with low cost and high yield, which would afford sufficient amounts of high-purity compounds for chromatographic purposes and pharmacological activity screening. Copyright © 2014 John Wiley & Sons, Ltd.

  6. LAP6/POLYKETIDE SYNTHASE A and LAP5/POLYKETIDE SYNTHASE B Encode Hydroxyalkyl α-Pyrone Synthases Required for Pollen Development and Sporopollenin Biosynthesis in Arabidopsis thaliana[C][W][OA

    Science.gov (United States)

    Kim, Sung Soo; Grienenberger, Etienne; Lallemand, Benjamin; Colpitts, Che C.; Kim, Sun Young; Souza, Clarice de Azevedo; Geoffroy, Pierrette; Heintz, Dimitri; Krahn, Daniel; Kaiser, Markus; Kombrink, Erich; Heitz, Thierry; Suh, Dae-Yeon; Legrand, Michel; Douglas, Carl J.

    2010-01-01

    Plant type III polyketide synthases (PKSs) catalyze the condensation of malonyl-CoA units with various CoA ester starter molecules to generate a diverse array of natural products. The fatty acyl-CoA esters synthesized by Arabidopsis thaliana ACYL-COA SYNTHETASE5 (ACOS5) are key intermediates in the biosynthesis of sporopollenin, the major constituent of exine in the outer pollen wall. By coexpression analysis, we identified two Arabidopsis PKS genes, POLYKETIDE SYNTHASE A (PKSA) and PKSB (also known as LAP6 and LAP5, respectively) that are tightly coexpressed with ACOS5. Recombinant PKSA and PKSB proteins generated tri-and tetraketide α-pyrone compounds in vitro from a broad range of potential ACOS5-generated fatty acyl-CoA starter substrates by condensation with malonyl-CoA. Furthermore, substrate preference profile and kinetic analyses strongly suggested that in planta substrates for both enzymes are midchain- and ω-hydroxylated fatty acyl-CoAs (e.g., 12-hydroxyoctadecanoyl-CoA and 16-hydroxyhexadecanoyl-CoA), which are the products of sequential actions of anther-specific fatty acid hydroxylases and acyl-CoA synthetase. PKSA and PKSB are specifically and transiently expressed in tapetal cells during microspore development in Arabidopsis anthers. Mutants compromised in expression of the PKS genes displayed pollen exine layer defects, and a double pksa pksb mutant was completely male sterile, with no apparent exine. These results show that hydroxylated α-pyrone polyketide compounds generated by the sequential action of ACOS5 and PKSA/B are potential and previously unknown sporopollenin precursors. PMID:21193570

  7. Synthesis of 6-Trimethylsilyl-a-pyrone from 2,6-Bis(trimethylsilyl)-pyran via Mild Aerobic Oxidation%氧气氧化2,6-二-(三甲基硅基)吡喃为6-三甲基硅基-α-吡喃酮

    Institute of Scientific and Technical Information of China (English)

    周德军; Matsuya Yuji

    2013-01-01

    In this study,an effective and mild method for the synthesis of 6-trimethylsilyl-α-pyrone was successfully developed. 6-Trimethylsilyl-α-pyrone,a very important intermediate in organic synthesis,was mildly synthesized from pyrane derivative via an aerobic oxidation at room temperature,without any solvents and catalysts. Furthermore,the possible mechanism of the reaction was proposed.%开发出一种合成6-三甲基硅基α-吡喃酮的有效方法.在无溶剂无任何催化剂的氧气气氛中,室温条件下温和地将2,6-二-(三甲基硅基)吡喃通过氧化反应转化成6-三甲基硅基α-吡喃酮,并且给出了该反应可能的机理.

  8. Protective Effects of Dimedone Pyrone on Podocytes in Rats with ...

    African Journals Online (AJOL)

    another with familial clustering, suggesting that genetic factors play an important role [6]. The expensiveness of renal replacement therapy ... rats. During fasting alloxan was injected through tail veins at a dose of 42 mg/kg of body weight to.

  9. New gamma-pyrone propionates from the Indian Ocean sacoglossam Placobranchus ocellatus

    Digital Repository Service at National Institute of Oceanography (India)

    Manzo, E.; Ciavatta, M.L.; Gavagnin, M.; Mollo, E.; Wahidullah, S.; Cimino, G.

    methine H-7 and the methyl at C-12. The perox- ide bridge was a-oriented with respect to the plane of the 16 1.88 s 7.2 q — 1.84 s 7.0 q — 17 1.98 s 9.8 q — 1.94 s 12.9 q — 18 1.25 s 15.5 q H-7, H-13 1.51 s 18.9 q H-7, H-13 19 1.78 s 23.4 q H-7 1.20 s 21... resonances (Table 1) according to the presence of a conjugated carbonyl group (C-3, d 182.0), four quaternary carbons (C-1, d 162.5; C-2, d 100.9; C-4, d 116.5; C-5, d 164.6) and three methyl sig- nals (MeO–, d 56.4; C-16, d 7.2; C-17, d 9.8), attribut- able...

  10. New pyrone and quinoline alkaloid from Almeidea rubra and their trypanocidal activity

    Energy Technology Data Exchange (ETDEWEB)

    Ambrozin, Alessandra R.P.; Mafezoli, Jair; Vieira, Paulo C.; Fernandes, Joao B.; Silva, M. Fatima das G.F. da [Sao Carlos Univ., SP (Brazil). Dept. de Quimica]. E-mail: paulo@dq.ufscar.br; Ellena, Javier A. [Sao Paulo Univ., Sao Carlos, SP (Brazil). Inst. de Fisica; Albuquerque, Sergio de [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Ciencias Farmaceuticas. Dept. de Analises Clinicas, Toxicologicas, Bromatologicas

    2005-05-15

    The investigation of the ethyl acetate fraction of methanol extract from leaves of Almeidea rubra A. St.-Hil. (Rutaceae) afforded two new compounds 4-methoxy-6-[2-(methylamino)phenyl]-2Hpyran- 2-one and rel-(7R,8R)-8-[(E)-3-hydroxy-3-methyl-1-butenyl]-4,8-dimethoxy-5,6,7,8- tetrahydrofuro[2,3-b]quinoline-7-yl acetate, along with the known compounds arborinine, N-methyl- 1-hydroxy-3-methoxyacridone, skimmianine, kokusagine, isodutaduprine, isoskimmianine, and isokokusagine. Their structures were established based on their spectral data, and for the new compounds these data are described herein. Additionally, these compounds were assayed on the tripomastigote forms of Trypanosoma cruzi showing moderate trypanocidal activity. (author)

  11. OPTIMIZATION OF 6-PENTYL-ALPHA-PYRONE PRODUCTION BY SOLID STATE FERMENTATION USING SUGARCANE BAGASSE AS RESIDUE

    Directory of Open Access Journals (Sweden)

    Natalia C. Ladeira

    2010-09-01

    Full Text Available Solid state fermentation (SSF has been used as a model for the study of metabolism and physiology of microorganisms. The aim of the present study was to enhance 6-PP production by Trichoderma harzianum 4040 in solid state fermentation using sugarcane bagasse as a residue. A fractional factorial design was used to select the components of the nutrient solution. The fermentation was carried out during 9 days, and the aroma extraction was done on the third, fifth, seventh, and ninth days using organic solvent. On the seventh day the major concentration of 6-PP was found. The variables glucose, sucrose, and MgSO4 were found to be significant statistically (p> 0.05 as components of the nutrient solution used in the production of 6-PP by filamentous fungi in SSF using sugarcane bagasse as a residue. GC-MS was used for quantification of 6-PP aroma.

  12. Dianthosaponins A-F, triterpene saponins, flavonoid glycoside, aromatic amide glucoside and γ-pyrone glucoside from Dianthus japonicus.

    Science.gov (United States)

    Nakano, Takahiro; Sugimoto, Sachiko; Matsunami, Katsuyoshi; Otsuka, Hideaki

    2011-01-01

    From aerial parts of Dianthus japonicus, six new and seven known oleanane-type triterpene saponins were isolated. The structures of the new saponins, named dianthosaponins A-F, were elucidated by means of high resolution mass spectrometry, and extensive inspection of one- and two-dimensional NMR spectroscopic data. A new C-glycosyl flavone, a glycosidic derivative of anthranilic acid amide and a maltol glucoside were also isolated.

  13. Pyrone-based Cu(II) complexes, their characterization, DFT based conformational drift from square planar to square pyramidal geometry and biological activities

    Indian Academy of Sciences (India)

    Pradeep Kumar Vishwakarma; Jan Mohammad Mir; Ram Charitra Maurya

    2016-04-01

    This work deals with the synthesis and characterization of a series of three -Dehydroacetic acid- 4-phenyl-3-thiosemicarbazide (H2dha-ptsc) Schiff base Cu(II) complexes based on combined experimental and theoretical approach, having the general composition formula as [Cu(dha-ptsc)(L-L)], where L-L is H2O, 2,2-bipyridine (bipy) or 1,10-phenanthroline (phen). H2O containing complex acts as origin for the latter two complexes and in due course, the geometry of the complex changes from square planar to square pyramidal. DFT calculations were carried out for both the geometrical forms. B3LYP/LANL2DZ level of theory was used to carry out the required computations. From the overall DFT computations, square pyramidal geometry was found to be more stable as compared to the square planar conformation for the complexes under investigation. Super oxide dismutation, thermal behaviour and electrochemical activity were also studied. The results have shown satisfactory super oxide scavenging potential, high degree of thermal resistance and efficient redox properties for the title complexes. Moreover, charge analysis and nonlinear optical properties were computed to establish a comprehensive note of atomic constituents differing in nature of charge delocalization.

  14. 仙人掌中一个新α-吡喃酮成分的分离与结构鉴定%The isolation and identification of a new α-pyrone from Opuntia dillenii

    Institute of Scientific and Technical Information of China (English)

    邱鹰昆; 窦德强; 裴玉萍; 吉川雅之; 松田久司; 陈英杰

    2003-01-01

    目的研究仙人掌的化学成分.方法应用多种柱色谱方法进行分离和纯化,NMR和MS等波谱解析化学结构.结果从仙人掌肉质茎的乙醇提取物中分离出6个化合物,其结构分别鉴定为:3-O-甲基异鼠李黄素(1)、4-乙氧基-6-羟甲基-α-吡喃酮(2)、正十七醇(3)、香草酸(4)、异鼠李黄素-3-O-鼠李糖苷(5)和芦丁(6).结论化合物2为新化合物,化合物1、3、4、5均为首次从本属植物中分离得到,化合物6为本植物首次分离得到.

  15. Trypanocidal activity of coumarins and styryl-2-pyrones from Polygala sabulosa A.W. Bennett (Polygalaceae Atividade tripanocida de cumarinas e estiril-2-pironas de Polygala sabulosa A.W. Bennett (Polygalaceae

    Directory of Open Access Journals (Sweden)

    Moacir G. Pizzolatti

    2008-06-01

    Full Text Available Bioactivity of fractions and compounds obtained from Polygala sabulosa against Trypanosoma cruzi epimastigote, blood trypomastigote and amastigote forms were evaluated in vitro. Dichloromethane and ethyl acetate fractions showed a strong trypanocidal activity on epimastigotes (IC50 A bioatividade das frações e compostos obtidos de Polygala sabulosa contra as formas epimastigota, tripomastigota sanguínea e amastigota de Trypanosoma cruzi foram avaliadas in vitro. Frações diclorometano e acetato de etila mostraram potente atividade tripanocida sob as formas epimastigotas (IC50 < 10,4 µg/mL. Análises por cromatografia em camada delgada destas frações confirmaram a presença de compostos previamente descritos (dihidroestiril-2-pironas, estiril-2-pironas e 6-metoxi-7-preniloxicumarina. Após o fracionamento da fração diclorometano por cromatografia em coluna, obteve-se o composto α-espinasterol e da fração acetato de etila obtiveram-se os compostos apigenina, quercetina e uma quercetina-3- O-glicosídeo, todos descritos pela primeira vez para o gênero Polygala. 4-metoxi-6-(11,12-metilenodioxi-14-metoxidihidroestiril-2-pirona, 4-metoxi-6-(11,12-dimetoxi-14-metoxiestiril-2-pirona, 6-metoxi-7-preniloxicumarina e quercetina-3- O-glicosídeo mostraram fraca atividade contra a forma tripomastigota sanguínea (IC50 < 1008,6 µg/mL. A cumarina prenilada foi o composto mais ativo contra ambas as formas epimastigota e tripomastigota, com IC50 10,5 e 88,2 µg/mL, respectivamente. A atividade hemolítica e a toxicidade celular de cada composto foram também avaliadas. Além disso, 4-metoxi-6-(11,12-metilenodioxi-14-metoxidihidroestiril-2-pirona e 6-metoxi-7-preniloxicumarina reduziram em quatro vezes a infecção em ratos por Vero Cells nas concentrações de 100 e 50 µg/mL respectivamente. Esses resultados mostram, pela primeira vez, a atividade de compostos de P. sabulosa contra T. cruzi.

  16. Neosataria, replacement name for Sataria Annandale, 1920 (Mollusca: Gastropoda: Bithyniidae), preoccupied by Sataria Roewer, 1915 (Arachnida: Opiliones: Sclerosomatidae).

    Science.gov (United States)

    Kulkarni, Siddharth; Khot, Rahul

    2015-06-24

    The family Bithyniidae is represented in tropical Asia by the following genera, Bithynia, Digonistoma, Mysorella, Parabithynia, Emmericiopsis, Hydrobioides, Parafossarulus, Pseudovivipara, Sataria and Wattebladia (Dudgeon 1999; Pyron & Brown 2015).

  17. Synthesis of δ-lactonic pheromones ofXylocopa hirsutissima andVespa orientalis and an allomone of some ants of genusCamponotus.

    Science.gov (United States)

    Bacardit, R; Moreno-Mañas, M

    1983-06-01

    Simple preparations ofcis-3,6-dimethyltetrahydro-2-pyrone, VII,6-n-undecyltetrahydro-2-pyrone, XVIIb, and 6-n-pentyl-5,6-dihydro-2-pyrone, XVIa, have been achieved. Products VII and XVIIb, respectively, are the major constituent of the pheromonal blend of a carpenter bee (Xylocopa hirsutissima) and the pheromone of the queens of the Oriental hornet (Vespa orientalis). The lactone XVIa is a suspected defensive allomone in two species of formicine ants of the genusCamponotus. All three compounds have been prepared from dehydroacetic acid, I, a cheap and industrially available starting material.

  18. 5-Hydroxy-2-methyl-4H-pyran-4-one

    Directory of Open Access Journals (Sweden)

    Bernhard K. Keppler

    2009-02-01

    Full Text Available The title compound, C6H6O3, is a member of the pyrone family. The molecules are planar (r.m.s. deviation of the asymmetric unit is 0.0248 Å, whereas that of the dimer is 0.0360 Å and they are dimerized due to intermolecular O—H...O hydrogen bonds. The dimers are connected to each other through hydrogen bonds involving the CH3 group and the hydroxy O atom. There are π–π interactions between the centroids of the pyrone rings at a distance of 3.8552 (13 Å. A C—H...π interaction also exists between the carbonyl group and the centroid CgA of the pyrone ring, with O...CgA = 3.65 (1 Å and C...CgA = 4.363 (2 Å.

  19. Fluorine effect on pericyclic and pseudopericyclic processes: Evidences and ab initio theory

    Indian Academy of Sciences (India)

    Lakshminarayanan Akilandeswari; Madhavan Jaccob; Ponnambalam Venuvanalingam

    2009-09-01

    Electrocyclic ring opening (ERO) reactions of 2-pyrone, 2-pyranol and pyran and their fluoro compounds (1-6) have been studied at MP2/6-31G() level with special emphasis on the influence of fluorine on these pericyclic/pseudopericyclic processes. Calculations clearly predict that substitution of fluorine at C6 favour the reaction both kinetically and thermodynamically. Magnetic susceptibility anisotropy (aniso), NICS(0), NBO and bond critical property (BCP) analyses clearly illustrate the following; 2-pyrone (1) and 6-fluoro-2-pyrone (2) reactions are pseudopericyclic; 6-fluoro-2-pyranol (reaction 4) corresponds to a borderline case; 2-pyranol (3) and pyran (5) and 6-fluoro pyran (6) reactions are clearly pericyclic in character. Correspondingly pseudeopericyclic reactions show up orbital disconnections and fluorine delays the occurrence of orbital disconnections on the reaction trajectory.

  20. Screening of various low-grade biomass materials for low temperature gasification: Method development and application

    DEFF Research Database (Denmark)

    Thomsen, Tobias Pape; Ravenni, Giulia; Holm, Jens Kai;

    2015-01-01

    method and the subsequent use of the method to identify promising e but currently unproven, low-grade biomass resources for conversion in Pyroneer systems. The technical assessment is conducted by comparing the results from a series of physical-mechanical and thermochemical experiments to a set of proven...... references. The technical assessment is supplemented by an evaluation of practical application and overall energy balance. Applying the developed method to 4 references and 18 unproven low-grade potential fuels, indicated that one of these unproven candidates was most likely unsuited for Pyroneer...

  1. Heterologous gene expression and functional analysis of a type III polyketide synthase from Aspergillus niger NRRL 328

    Energy Technology Data Exchange (ETDEWEB)

    Kirimura, Kohtaro, E-mail: kkohtaro@waseda.jp; Watanabe, Shotaro; Kobayashi, Keiichi

    2016-05-13

    Type III polyketide synthases (PKSs) catalyze the formation of pyrone- and resorcinol-types aromatic polyketides. The genomic analysis of the filamentous fungus Aspergillus niger NRRL 328 revealed that this strain has a putative gene (chr-8-2: 2978617–2979847) encoding a type III PKS, although its functions are unknown. In this study, for functional analysis of this putative type III PKS designated as An-CsyA, cloning and heterologous expression of the An-CsyA gene (An-csyA) in Escherichia coli were performed. Recombinant His-tagged An-CsyA was successfully expressed in E. coli BL21 (DE3), purified by Ni{sup 2+}-affinity chromatography, and used for in vitro assay. Tests on the substrate specificity of the His-tagged An-CsyA with myriad acyl-CoAs as starter substrates and malonyl-CoA as extender substrate showed that His-tagged An-CsyA accepted fatty acyl-CoAs (C2-C14) and produced triketide pyrones (C2-C14), tetraketide pyrones (C2-C10), and pentaketide resorcinols (C10-C14). Furthermore, acetoacetyl-CoA, malonyl-CoA, isobutyryl-CoA, and benzoyl-CoA were also accepted as starter substrates, and both of triketide pyrones and tetraketide pyrones were produced. It is noteworthy that the His-tagged An-CsyA produced polyketides from malonyl-CoA as starter and extender substrates and produced tetraketide pyrones from short-chain fatty acyl-CoAs as starter substrates. Therefore, this is the first report showing the functional properties of An-CsyA different from those of other fungal type III PKSs. -- Highlights: •Type III PKS from Aspergillus niger NRRL 328, An-CsyA, was cloned and characterized. •An-CsyA produced triketide pyrones, tetraketide pyrones and pentaketide resorcinols. •Functional properties of An-CsyA differs from those of other fungal type III PKSs.

  2. Deodarone Isomers in Cedrus atlantica Essential Oils and Tar Oils.

    Science.gov (United States)

    Nama, Anne Marie; Bighelli, Ange; Ghanmi, Mohamed; Satrani, Badr; Casanova, Joseph; Tomi, Félix

    2015-11-01

    Deodarone [2,2,6-trimethyl-6-(4-methylcyclohex-3-enyl)-tetrahydro-4-pyrone] is a sesquiterpene tetrahydro-γ-pyrone related to bisabolene and atlantone, first isolated from Cedrus deodora essential oil. With respect to the stereochemistry of the asymmetric carbons C4 and C8, two diastereoisomers may be distinguished. Identification and quantification of both diastereoisomers in wood and tar oils from C. atlantica has been achieved using 13C NMR spectroscopy, in combination with GC (polar column). The contents of (4R,8R)- and (4R,8S)-deodarone varied between 1.1-2.8% and 1.0-3.0%, respectively.

  3. A rare γ-pyranopyrazole skeleton: design, one-pot synthesis and computational study.

    Science.gov (United States)

    Üçüncü, Muhammed; Cantürk, Ceren; Karakuş, Erman; Zeybek, Hüseyin; Bozkaya, Uğur; Soydaş, Emine; Şahin, Ertan; Emrullahoğlu, Mustafa

    2016-08-21

    Drawing upon a consecutive amide coupling and intramolecular cyclisation pathway, a one-pot, straightforward synthetic route has been developed for a range of pyrazole fused γ-pyrone derivatives. The reaction mechanism proposed for the chemoselective formation of γ-pyranopyrazole is furthermore fully supported by experimental and computational studies.

  4. Infectopyrone, a potential mycotoxin from Alternaria infectoria

    DEFF Research Database (Denmark)

    Larsen, Thomas Ostenfeld; Perry, N.B.; Andersen, Birgitte

    2003-01-01

    A new metabolite, infectopyrone (1), has been isolated from the filamentous fungus Alternaria infectoria. The structure of 1 was elucidated by analysis of 2D NMR spectroscopic data. Compound 1 is an alpha-pyrone resembling known toxins, and is a useful phenotaxonomic marker for the A. infectoria ...

  5. Trichoderma volatiles effecting Arabidopsis

    DEFF Research Database (Denmark)

    Ramadan, Metwaly; Gigolashvili, Tamara; Grosskinsky, Dominik Kilian

    2015-01-01

    volatile of T. asperellum IsmT5 was identified to be 6-pentyl-α-pyrone (6PP), which was solely applied to A. thaliana to verify the growth and defense reactions. Most noticeable is that A. thaliana preexposed to 6PP showed significantly reduced symptoms when challenged with Botrytis cinerea and Alternaria...

  6. Infectopyrone, a potential mycotoxin from Alternaria infectoria

    DEFF Research Database (Denmark)

    Larsen, Thomas Ostenfeld; Perry, N.B.; Andersen, Birgitte

    2003-01-01

    A new metabolite, infectopyrone (1), has been isolated from the filamentous fungus Alternaria infectoria. The structure of 1 was elucidated by analysis of 2D NMR spectroscopic data. Compound 1 is an alpha-pyrone resembling known toxins, and is a useful phenotaxonomic marker for the A. infectoria ...

  7. Recovery of volatile bioproducts by pervaporation

    Energy Technology Data Exchange (ETDEWEB)

    Boeddeker, K.W.

    1994-01-01

    Organophilic prevaporation is linkened to steam distillation in the recovery of volatile bioproducts of fermentation or plant origin. Potential applications are to biosynthetic chemicals (e.g., EtOH; BuOH), aroma compounds (e.g., gamma-decalactone; 6-pentyl-2-pyrone), and essential oils. Unlike steam distillation, pervaporation may be combined with an active fermenter. (orig.)

  8. Triacetic acid lactone production from Saccharomyces cerevisiae

    Science.gov (United States)

    Triacetic acid lactone (TAL) is a potential platform chemical produced from acetyl-CoA and malonyl-CoA by the Gerbera hybrida 2-pyrone synthase (2PS) gene. Studies are ongoing to optimize production, purification, and chemical modification of TAL, which can be used to create the commercial chemicals...

  9. Secondary metabolites from Penicillium corylophilum isolated from damp buildings.

    Science.gov (United States)

    McMullin, David R; Nsiama, Tienabe K; Miller, J David

    2014-01-01

    Indoor exposure to the spores and mycelial fragments of fungi that grow on damp building materials can result in increased non-atopic asthma and upper respiratory disease. The mechanism appears to involve exposure to low doses of fungal metabolites. Penicillium corylophilum is surprisingly common in damp buildings in USA, Canada and western Europe. We examined isolates of P. corylophilum geographically distributed across Canada in the first comprehensive study of secondary metabolites of this fungus. The sesquiterpene phomenone, the meroterpenoids citreohybridonol and andrastin A, koninginin A, E and G, three new alpha pyrones and four new isochromans were identified from extracts of culture filtrates. This is the first report of koninginins, meroterpenoids and alpha pyrones from P. corylophilum. These secondary metabolite data support the removal of P. corylophilum from Penicillium section Citrina and suggest that further taxonomic studies are required on this species.

  10. Synthesis and biological evaluation of kojic acid derivatives containing 1,2,4-triazole as potent tyrosinase inhibitors.

    Science.gov (United States)

    Xie, Wenlin; Zhang, Jingai; Ma, Xiaojing; Yang, Wenqian; Zhou, Ying; Tang, Xufu; Zou, Yan; Li, Hui; He, Jingjing; Xie, Shimin; Zhao, Yunhui; Liu, Fengping

    2015-11-01

    A series of 5-substituted-3-[5-hydroxy-4-pyrone-2-yl-methymercapto]-4-amino-1,2,4-triazole derivatives were synthesized by nucleophilic substitution reaction of 5-hydroxy-2-chloromethyl -4H-pyran-4-one with 5-substituted-3-mercapto-4-amino-1,2,4-triazole, and their inhibitory effects on mushroom tyrosinase were evaluated. The results indicated that most of the synthesized compounds exhibited significant inhibitory activity. Specifically, 5-(4-chlorophenyl)-3-[5-hydroxy-4-pyrone-2-yl-methymercapto]-4-amino-1,2,4-triazole (6j) exhibited the most potent tyrosinase inhibitory activity with IC50 value of 4.50 ± 0.34 μm. The kinetic studies of the compound (6j) demonstrated that the inhibitory effects of the compound on the tyrosinase were belonging to competitive inhibitors. Meanwhile, the structure-activity relationship was also discussed.

  11. Antifungal Constituents from the Roots of Piper dilatatum Rich.

    Directory of Open Access Journals (Sweden)

    Ruilan Alves dos Santos

    2013-01-01

    Full Text Available The compounds (+-(7S,8R-epoxy-5,6-didehydrokavain (1, flavokavain B (2, β-sitosterol (3, and stigmasterol (4 are reported here as chemical constituents of Piper dilatatum Rich. (Piperaceae. Their structures were determined on the basis of their spectroscopic data (1H and 13C NMR, MS, and IR. The antifungal activities of pyrone 1 (1 μg and chalcone 2 (100 μg were determined by means of direct bioautography against Cladosporium cladosporioides and C. sphaerospermum. Results indicate P. dilatatum as a candidate for the development of novel antifungal phytotherapic products as well as point out pyrone 1 as a promising hit compound in the quest for novel antifungal agents.

  12. 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.

  13. Effective and novel enantioselective preparation of pyranopyrazoles and pyranocoumarins that is catalyzed by a quinine-derived primary amine.

    Science.gov (United States)

    Yang, Sai; Shen, Liu-lan; Kim, Yoon-Jung; Jeong, Jin-Hyun

    2016-01-14

    In this study, we executed an effective and novel enantioselective Michael/cyclodehydration sequential reaction between pyrazolin-5-one (or 4-hydroxy-2-pyrone) and chalcones that is catalyzed by a quinine-derived primary amine L7 in the presence of Boc-D-Phg-OH. Chiral pyranopyrazoles and pyranocoumarins were obtained in excellent enantioselectivities (up to 93%) with moderate yields and moderate enantioselectivities with high yields (up to 84%).

  14. (Z-3-(1-Hydroxy-3-oxobut-1-enyl-6-nitro-2H-chromen-2-one

    Directory of Open Access Journals (Sweden)

    Nishith Saurav Topno

    2013-02-01

    Full Text Available In the title compound, C13H9NO6, the coumarin system has the benzene ring aligned at 0.61 (18° with respect to the pyrone ring. An intramolecular O—H...O hydrogen bond stabilizes the molecular conformation and a C—H...O contact also occurs. In the crystal, weak C—H...O interactions link the molecules, forming inversion dimers.

  15. Production of mycotoxins on artificially and naturally infested building materials

    DEFF Research Database (Denmark)

    Nielsen, Kristian Fog; Gravesen, S.; Nielsen, P.A.

    1999-01-01

    In this study, the ability to produce mycotoxins during growth on artificially infested building materials was investigated for Penicillium chrysogenum, Pen. polonicum, Pen. brevicompactum, Chaetomium spp., Aspergillus ustus, Asp. niger, Ulocladium spp., Alternaria spp., and Paecilomyces spp., all......., alternariol and alternariol monomethyl ether were detected. From Ulocladium spp., Paecilomyces spp., and Asp. ustus no known mycotoxins were detected, although the latter two are known mycotoxin producers. Asp. niger produced several naphtho-gamma-pyrones and tetra-cyclic compounds. All investigated species...

  16. Analgesic Potential of Opuntia dillenii and Its Compounds Opuntiol and Opuntioside Against Pain Models in Mice

    OpenAIRE

    Faheema Siddiqui; Lubna Abidi; Lubna; Ching Fidelis Poh; Sabira Naqvi; Shaheen Faizi; Ahsana Dar Farooq

    2016-01-01

    Opuntia dillenii (Nagphana) traditionally used against inflammation and also possess analgesic effect. Thus in the present study analgesic properties of O. dillenii cladode methanol extract, its fractions obtained via vacuum liquid chromatography along with isolated α-pyrones, opuntiol and its glucoside, opuntioside were analyzed. The acetic acid-induced writhes were reduced by O. dillenii test agents with opuntioside being most effective (IC 50 26 ± 0.9 mg/kg) and equipotent to diclofenac an...

  17. Main Ustilaginoidins and Their Distribution in Rice False Smut Balls

    Directory of Open Access Journals (Sweden)

    Jiajia Meng

    2015-10-01

    Full Text Available Rice false smut has become an increasingly serious fungal disease in rice (Oryza sativa L. production worldwide. Ustilaginoidins are bis-naphtho-γ-pyrone mycotoxins previously isolated from the rice false smut balls (FSBs infected by the pathogen Villosiclava virens in rice spikelets on panicles. To investigate the main ustilaginoidins and their distribution in rice FSBs, five main bis-naphtho-γ-pyrones, namely ustilaginoidins A (1, G (2, B (3, I (4 and C (5, were isolated and identified by NMR and high-resolution mass spectrometry as well as by comparison with the data in the literature. The rice FSBs at early, middle and late maturity stages were divided into their different parts and the contents of five main ustilaginoidins for each part were determined by HPLC analysis. The results revealed that the highest levels of ustilaginoidins were in late stage rice FSBs, followed by those at middle stage. Most ustilaginoidins, 96.4% of the total quantity, were distributed in the middle layer at early stage. However, ustilaginoidins were mainly distributed in the outer and middle layers at middle and late stages. Small amounts of ustilaginoidins A (1 and G (2 were found in the inner part of rice FSBs at each maturity stage. The contents of ustilaginoidins A (1 and G (2 without hydroxymethyl groups at C-2 and C-2’ of the γ-pyrone rings in rice FSBs were relatively high at early stage, while the contents of ustilaginoidins B (3, I (4, and C (5 with hydroxymethyl groups at C-2 or C-2’ were relatively high at late stage.

  18. Hypotensive activity, toxicology and histopathology of opuntioside-I and methanolic extract of Opuntia dillenii.

    Science.gov (United States)

    Saleem, Rubeena; Ahmad, Mohammad; Azmat, Aisha; Ahmad, Syed Iqbal; Faizi, Zareen; Abidi, Lubna; Faizi, Shaheen

    2005-10-01

    Methanolic extract of Opuntia dillenii cladodes and its pure compound alpha-pyrone glycoside, opuntioside-I showed potent hypotensive activity in normotensive rats. Both the extract and opuntioside-I showed comparable effect of 44-54% fall in Mean Arterial Blood Pressure (MABP) at the dose of 10 mg/kg. No mortality was observed in rats even at the doses of 1000 mg/kg/d and 900 mg/kg/d per oral of extract and opuntioside-I respectively. However, histopathology revealed adverse effects of high doses on liver and spleen of the experimental animals.

  19. Pyronaridine-artesunate granules versus artemether-lumefantrine crushed tablets in children with Plasmodium falciparum malaria: a randomized controlled trial

    OpenAIRE

    Kayentao Kassoum; Doumbo Ogobara K; Pénali Louis K; Offianan André T; Bhatt Kirana M; Kimani Joshua; Tshefu Antoinette K; Kokolomami Jack HT; Ramharter Michael; de Salazar Pablo Martinez; Tiono Alfred B; Ouédraogo Alphonse; Bustos Maria Dorina G; Quicho Frederick; Borghini-Fuhrer Isabelle

    2012-01-01

    Abstract Background Children are most vulnerable to malaria. A pyronaridine-artesunate pediatric granule formulation is being developed for the treatment of uncomplicated Plasmodium falciparum malaria. Methods This phase III, multi-center, comparative, open-label, parallel-group, controlled clinical trial included patients aged ≤12 years, bodyweight ≥5 to 90% (P 3 times the upper limit of normal (ULN) and peak total bilirubin >2xULN (i.e. within the Hy’s law definition). Conclusions The pyron...

  20. In vitro antitrypanosomal activity of some phenolic compounds from propolis and lactones from Fijian Kawa (Piper methysticum).

    Science.gov (United States)

    Otoguro, Kazuhiko; Iwatsuki, Masato; Ishiyama, Aki; Namatame, Miyuki; Nishihara-Tsukashima, Aki; Kiyohara, Hiroaki; Hashimoto, Toshihiro; Asakawa, Yoshinori; Omura, Satoshi; Yamada, Haruki

    2012-07-01

    During our search to discover new antitrypanosomal compounds, eight known plant compounds (three phenolic compounds and five kawa lactones) were evaluated for in vitro activity against Trypanosoma brucei brucei. Among them, we found two phenolic compounds and three kawa lactones possessing an α-pyrone influenced antitrypanosomal property. In particular, β-phenethyl caffeate, farnesyl caffeate and dihydrokawain exhibited high or moderate selective and potent antitrypanosomal activity in vitro. We detail here the antitrypanosomal activity and cytotoxicities of the compounds, in comparison with two commonly used antitrypanosomal drugs (eflornithine and suramin). Our findings represent the first report of the promising trypanocidal activity of these compounds.

  1. I. Structural studies of termite defense secretions. II. Structural studies of natural products of marine nudibranchs. [Kempene, tridachione

    Energy Technology Data Exchange (ETDEWEB)

    Solheim, B.A.

    1977-12-01

    Three families of termites have the ability to produce a sticky secretion that envelopes and immobilizes the enemy. In the family Termitidae the secretion contains the diterpenoid hydrocarbons, kempene I and kempene II. The molecular structure of kempene II from the termite, Nasutitermes kempae, is described in detail. Another species of termite, Cubitermes umbratus, contained the diterpenoid hydrocarbon biflora-4,10-19,15-triene in the secretion and this compound is described. Studies were also conducted on the mucous secretion of the pedal gland of the marine nudibranch, Tidachiella diomedea. Tridachione, a substituted ..gamma..-pyrone, was isolated in the pure state and its molecular structure is described in detail. (HLW)

  2. Reactions of 3-Formylchromone with Active Methylene and Methyl Compounds and Some Subsequent Reactions of the Resulting Condensation Products

    Directory of Open Access Journals (Sweden)

    M. Lácova

    2005-08-01

    Full Text Available This review presents a survey of the condensations of 3-formylchromone with various active methylene and methyl compounds, e.g. malonic or barbituric acid derivatives, five-membered heterocycles, etc. The utilisation of the condensation products for the synthesis of different heterocyclic systems, which is based on the ability of the γ-pyrone ring to be opened by the nucleophilic attack is also reviewed. Finally, the applications of microwave irradiation as an unconventional method of reaction activation in the synthesis of condensation products is described and the biological activity of some chromone derivatives is noted.

  3. Synthesis and Triethylamine-catalyzed Cyclization Reaction of 4-Pentyne-1,3-dione System Having Various Substituents

    Institute of Scientific and Technical Information of China (English)

    KURODA,Hirofumi; IZAWA,Hironori

    2008-01-01

    4-Pentyne-1,3-dione system having various substituents was synthesized in two steps and the cyclization behavior of the obtained 1 ,3-dicarbonyl compounds was examined. y-Pyrones and 2-alkylidene-2,3-dihydro-3-fu-ranones were obtained by the triethylamine-catalyzed cyclization of the 4-pentyne-l,3-dione system having a dike-tone moiety. Furthermore, a phenol derivative was obtained in the case of 4-pentyne-1,3-dione system having an ester moiety. Thus, it was found that the kind of substituents in the 4-pentyne-1,3-dione system remarkably influenced the selectivity in the cyclization.

  4. Antibiotic Extraction as a Recent Biocontrol Method for Aspergillus Niger andAspergillus Flavus Fungi in Ancient Egyptian mural paintings

    Science.gov (United States)

    Hemdan, R. Elmitwalli; Fatma, Helmi M.; Rizk, Mohammed A.; Hagrassy, Abeer F.

    Biodeterioration of mural paintings by Aspergillus niger and Aspergillus flavus Fungi has been proved in different mural paintings in Egypt nowadays. Several researches have studied the effect of fungi on mural paintings, the mechanism of interaction and methods of control. But none of these researches gives us the solution without causing a side effect. In this paper, for the first time, a recent treatment by antibiotic "6 penthyl α pyrone phenol" was applied as a successful technique for elimination of Aspergillus niger and Aspergillus flavus. On the other hand, it is favorable for cleaning Surfaces of Murals executed by tembera technique from the fungi metabolism which caused a black pigments on surfaces.

  5. 4-Hydroxy-3-[(2E-3-(3,4,5-trimethoxyphenylprop-2-enoyl]-2H-chromen-2-one

    Directory of Open Access Journals (Sweden)

    Lassaad Mechi

    2009-07-01

    Full Text Available A new chalcone of the coumarin, C21H18O7, containing an annulated α-pyrone ring, was obtained by condensation of the borate complex of acyl(hydroxycoumarin with trimethoxybenzaldehyde. The structure exhibits intramolecular hydrogen bonding between the hydroxyl oxygen and the ketonic oxygen in the coumarin group. The bicyclic coumarin fragment and the benzene ring form a dihedral angle of 17.1 (4°. The crystal packing involves dimers interconnected by C—H...O hydrogen bonding.

  6. I. Structural studies of termite defense secretions. II. Structural studies of natural products of marine nudibranchs. [Kempene, tridachione

    Energy Technology Data Exchange (ETDEWEB)

    Solheim, B.A.

    1977-12-01

    Three families of termites have the ability to produce a sticky secretion that envelopes and immobilizes the enemy. In the family Termitidae the secretion contains the diterpenoid hydrocarbons, kempene I and kempene II. The molecular structure of kempene II from the termite, Nasutitermes kempae, is described in detail. Another species of termite, Cubitermes umbratus, contained the diterpenoid hydrocarbon biflora-4,10-19,15-triene in the secretion and this compound is described. Studies were also conducted on the mucous secretion of the pedal gland of the marine nudibranch, Tidachiella diomedea. Tridachione, a substituted ..gamma..-pyrone, was isolated in the pure state and its molecular structure is described in detail. (HLW)

  7. Synthetic and structure-activity relationship of insecticidal bufadienolides.

    Science.gov (United States)

    Hidayat, Ace Tatang; Zainuddin, Achmad; Dono, Danar; Hermawan, Wawan; Hayashi, Hideo; Supratman, Unang

    2014-07-01

    A new synthetic analog of bufadienolide, methyl isobryophyllinate A (1), and a known synthetic analog, methyl isobersaldegenate-1,3,5-orthoacetate (2), were obtained by methanolysis of bryophyllin A (3) and bersaldegenin-1,3,5-orthoacetate (5) in basic solution. Structure-insecticidal activity relationship studies revealed both orthoacetate and alpha-pyrone moieties seemed to be essential structural elements for exhibiting insecticidal activity, whereas oxygenated substituents in the C ring enhanced the insecticidal activity against the third instar larvae of silkworm (Bombyx mori).

  8. A revision and key for the tribe Diaphorolepidini (Serpentes: Dipsadidae) and checklist for the genus Synophis.

    Science.gov (United States)

    Pyron, R Alexander; Arteaga, Alejandro; Echevarría, Lourdes Y; Torres-Carvajal, Omar

    2016-09-28

    The genus Synophis contains a number of enigmatic species, distributed primarily in the Andean highlands of northern South America. Their extreme crypsis and rarity has precluded detailed study of most species. A recent flurry of collection activity resulted in the accession of many new specimens, and the description of 4 new species in 2015, doubling the number of described taxa. However, lingering questions remain regarding the assignment of many new and historical specimens, the morphological limits and geographical ranges of the species, and their phylogenetic relationships. We analyze new and existing morphological and molecular data to produce a new molecular phylogeny and revised morphological descriptions. We validate the previously unavailable tribe name Diaphorolepidini Jenner, Pyron, Arteaga, Echevarría, & Torres-Carvajal tribe nov., describe a 9th species Synophis niceforomariae Pyron, Arteaga, Echevarría, & Torres-Carvajal sp. nov., and offer new Standard Names in English and Spanish for the group: Andean Shadow Snakes and Culebras Andinas de la Sombra, respectively. A variety of features such as vertebrae and hemipenes show an interesting range of variation in the group, which should be evaluated in future studies, to refine species limits and diagnoses further. Cryptic and undiscovered diversity undoubtedly remains, and we hope this summary provides a robust basis for future work.

  9. Preparation and assessment cytotoxic and hemolytic activities of Complexes from “Chelating Kojic–Lipid Conjugate”

    Directory of Open Access Journals (Sweden)

    Antônio S. C. Carvalho

    2012-06-01

    Full Text Available Complex bis (2-Oleicoyloxymethyl-5-hydroxy-gamma-pyrone copper (II and tris (2-Oleicoyloxymethyl-5-hydroxy-gamma-pyrone iron (III were prepared in ethanol using the structure "chelator conjugate kojic -lipid". This ester was obtained from kojic acid by improving their lipophilicity of obtaining metalobioactives with application in Medicinal Bioinorganic Chemistry. Through the technique ATR/FTIR, the values ​​of the infrared kojic acid has been updated and it was possible to characterize      the complex 1567m, 1511w (Cu (II←[O=C]2, and 1540m, 1519m (Fe(III←[O=C]3. These compounds no showed cytotoxic potential against B16 (melanoma and ACP02 (gastric adenocarcinoma (IC50> 5 μg mL-1 and low hemolytic activity (EC50> 250 μg mL-1.The preparation of these new molecules by structural modification techniques and these interesting biological results confirm the continuity of this studies related to these coordination complexes to glimpse the possibility of obtaining other derivatives/ analogues with significant biological potential of this metallo-bioactive.

  10. Analgesic Potential of Opuntia dillenii and Its Compounds Opuntiol and Opuntioside Against Pain Models in Mice

    Directory of Open Access Journals (Sweden)

    Faheema Siddiqui

    2016-05-01

    Full Text Available Opuntia dillenii (Nagphana traditionally used against inflammation and also possess analgesic effect. Thus in the present study analgesic properties of O. dillenii cladode methanol extract, its fractions obtained via vacuum liquid chromatography along with isolated α-pyrones, opuntiol and its glucoside, opuntioside were analyzed. The acetic acid-induced writhes were reduced by O. dillenii test agents with opuntioside being most effective (IC 50 26 ± 0.9 mg/kg and equipotent to diclofenac and β-sitosterol. Consistently, it also elicited most potent effect (IC 50: 28 ± 1.1 and 24 ± 1.2 mg/kg during early and late phases of formalin-induced paw licking, producing effect similar to diclofenac and indomethacin. It was also most effective in hot plate test. Naloxone (opioid antagonist reversed the analgesic effects of extract and fractions but failed to antagonize the opuntiol and opuntioside analgesic effects. In conclusion, edible O. dillenii extract, its fractions, opuntiol and opuntioside reduced peripheral and centrally mediated pain via opioid dependent and independent systems. Among them opuntioside emerged as most effective analgesic possibly due to the presence of glucose moiety at position 7 of its α-pyrone ring. This is the first report of opuntiol and opuntioside analgesic effect which may serve as lead compounds in designing of new analgesics.

  11. [Lymphedema: is there a treatment?].

    Science.gov (United States)

    Barrellier, M T

    1992-01-01

    More than hundred medical treatments for lymphedema have been described. This very high number shows the evidence of difficulties: lymphatics are very small vessels, under low pression and velocity respondent to spontaneous quiet lymphatic contractions. The treatments can be listed in 3 groups: 1) physiotherapeutic methods, increasing lymphatic flow: cold, field stimulation, manual lymph drainage, intermittent compression, heat; 2) drugs: venous agents (flavone, benzo-pyrone), and intraarterial lymphocytes injection, promoting lymphatic flow or increasing normal proteolysis by macrophages in order to remove trapped proteins from interstitial fluid; 3) surgical procedures subdivided in 2 groups: excisional techniques and bridging drainage techniques; radical or partial excision removes involved subcutaneous tissue, recently by the way of liposuction; Efforts to drain lymphedema by subcutaneous implants, pedical flaps, myocutaneous flaps, omental transposition and intestinal flaps are historical. Microsurgical lymphatic anastomosis to vein (nodo-venous then lymphovenous), and to lymphatic themselves are now performed: lymphatic collectors or venous autografts are interpositioned to by-pass lymphatic blockade with end-to end anastomosis. The free transplantation of a lymphatic flap with its own vascularisation from healthy inguinal nodes to axillary blockade is the last described procedure. Lymphatic anastomosis are not needed. Actually, physiotherapy is always first indicated. Benzo-pyrones are additive drugs. Excisional procedures concern monstruous lymphedema. Microsurgical bridging procedures can be attempted only for secondary lymphedemas. They could be of benefit if physiotherapy and elastic bandages, stockings or sleeves, could then be avoided. Studies assessing independently the efficiency of each procedure are needed.

  12. 5,7-Dihydroxy-2-(4-hydroxyphenyl)chroman-4-one (naringenin): X-ray diffraction structures of the naringenin enantiomers and DFT evaluation of the preferred ground-state structures and thermodynamics for racemization

    Science.gov (United States)

    Nesterov, Volodymyr V.; Zakharov, Lev N.; Nesterov, Vladimir N.; Calderon, Jose G.; Longo, Antonella; Zaman, Khadiza; Choudhury, Feroza Kaneez; Farrell, William; Shulaev, Vladimir; Richmond, Michael G.

    2017-02-01

    The R- and S-enantiomers of naringenin were separated by chiral supercritical fluid (SCF) and the absolute configuration of each enantiomer was established by X-ray crystallography. The solid-state data is in agreement with the reported circular dichroism spectra. Both enantiomers crystallize in the monoclinic crystal system in the space group P21 with two independent molecules in the asymmetric unit. In all molecules, the pyrone ring adopts a flattened chair-like conformation in which the C1 atom deviates from the plane drawn through the remaining five atoms of this heterocycle. The 4-hydroxyphenyl substituent located at C1 of the pyrone ring occupies an equatorial position and lies in a plane that is almost perpendicular to the aromatic platform associated with the heterocyclic portion of the molecule. Strong intramolecular O-H⋯O hydrogen bonding exists between the carbonyl moiety and the aryl hydroxyl group at C5. In both enantiomers, a favorable mutual orientation of two independent molecules promotes the formation of intermolecular O-H⋯O hydrogen bonds that link them into dimers. There are additional long-range intermolecular O-H⋯O hydrogen bonds and weak C-H⋯O contacts within the unit cell of each enantiomer that connect dimers in an extended network. DFT calculations have been performed and the thermodynamics for naringenin racemization via an acyclic chalcone have been computed. Eight energetically accessible conformations have been verified for S-naringenin.

  13. Discovery of novel A3 adenosine receptor ligands based on chromone scaffold.

    Science.gov (United States)

    Gaspar, Alexandra; Reis, Joana; Kachler, Sonja; Paoletta, Silvia; Uriarte, Eugenio; Klotz, Karl-Norbert; Moro, Stefano; Borges, Fernanda

    2012-07-01

    A project focused on the discovery of new chemical entities (NCEs) as AR ligands that incorporate a benzo-γ-pyrone [(4H)-1-benzopyran-4-one] substructure has been developed. Accordingly, two series of novel chromone carboxamides placed at positions C2 (compounds 2-13) and C3 (compounds 15-26) of the γ-pyrone ring were synthesized using chromone carboxylic acids (compounds 1 or 14) as starting materials. From this study and on the basis of the obtained structure-activity relationships it was concluded that the chromone carboxamide scaffold represent a novel class of AR ligands. The most remarkable chromones were compounds 21 and 26 that present a better affinity for A3AR (Ki = 3680 nM and Ki = 3750 nM, respectively). Receptor-driven molecular modeling studies provide information on the binding/selectivity data of the chromone. The data so far acquired are instrumental for future optimization of chromone carboxamide as a selective A3AR antagonist. Copyright © 2012 Elsevier Inc. All rights reserved.

  14. Chromone, a privileged scaffold for the development of monoamine oxidase inhibitors.

    Science.gov (United States)

    Gaspar, Alexandra; Silva, Tiago; Yáñez, Matilde; Vina, Dolores; Orallo, Franscisco; Ortuso, Francesco; Uriarte, Eugenio; Alcaro, Stefano; Borges, Fernanda

    2011-07-28

    Two series of novel chromone derivatives were synthesized and investigated for their ability to inhibit the activity of monoamine oxidase. The SAR data indicate that chromone derivatives with substituents in position 3 of γ-pyrone nucleus act preferably as MAO-B inhibitors, with IC(50) values in the nanomolar to micromolar range. Almost all chromone 3-carboxamides display selectivity toward MAO-B. Identical substitutions on position 2 of γ-pyrone nucleus result in complete loss of activity in both isoforms (chromones 2-12 except 3 and 5). Notably, chromone (19) exhibits an MAO-B IC(50) of 63 nM, greater than 1000-fold selectivity over MAO-A, and behaves as a quasi-reversible inhibitor. Docking experiments onto the MAO binding of the most active compound highlight different interaction patterns among the isoforms A and B. The differential analysis of the solvation effects among the chromone isomers gave additional insight about the superior outline of the 3-substituted chromone derivatives.

  15. 2D NMR-spectroscopic screening reveals polyketides in ladybugs.

    Science.gov (United States)

    Deyrup, Stephen T; Eckman, Laura E; McCarthy, Patrick H; Smedley, Scott R; Meinwald, Jerrold; Schroeder, Frank C

    2011-06-14

    Small molecules of biological origin continue to yield the most promising leads for drug design, but systematic approaches for exploring nature's cache of structural diversity are lacking. Here, we demonstrate the use of 2D NMR spectroscopy to screen a library of biorationally selected insect metabolite samples for partial structures indicating the presence of new chemical entities. This NMR-spectroscopic survey enabled detection of novel compounds in complex metabolite mixtures without prior fractionation or isolation. Our screen led to discovery and subsequent isolation of two families of tricyclic pyrones in Delphastus catalinae, a tiny ladybird beetle that is employed commercially as a biological pest control agent. The D. catalinae pyrones are based on 23-carbon polyketide chains forming 1,11-dioxo-2,6,10-trioxaanthracene and 4,8-dioxo-1,9,13-trioxaanthracene derivatives, representing ring systems not previously found in nature. This study highlights the utility of 2D NMR-spectroscopic screening for exploring nature's structure space and suggests that insect metabolomes remain vastly underexplored.

  16. Single step synthesis of strigolactone analogues from cyclic keto enols, germination stimulants for seeds of parasitic weeds.

    Science.gov (United States)

    Mwakaboko, Alinanuswe S; Zwanenburg, Binne

    2011-08-15

    The single step synthesis of a newly designed series of strigolactones (SLs) from cyclic keto enols is described. The germinating activity of these SL analogues towards seeds of the parasitic weeds Striga and Orobanche spp. is reported. The first of these SL analogues are derived from the hydroxyl γ-pyrones kojic acid and maltol, the second type from hydroxyl α-pyrones, namely, 4-hydroxy-6-methyl-2H-pyran-2-one and 4-hydroxy-coumarin and the third type from 1,3-diketones, namely, 1,3-cyclohexane-dione (dimedone) and tricyclic 1,3-dione. All keto enols are coupled in a single step with the appropriate D-ring precursor in the presence of a base to give the desired SL analogues. All SL analogues are acceptably biologically active in inducing the germination of seeds of Striga hermonthica and Orobanchecernua. Most interesting are the analogues derived from 4-hydroxy coumarin and dimedone, as they have a remarkably high biological activity towards the seeds of parasitic weeds at relatively low concentrations, comparable with that of the general standard stimulant GR24. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Study the active site of flavonoid applying radiation chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Wu Jilan; Sun Gang; Zhang Fugen; He Yongke; Li Jiuqiang [Department of Technical Physics, Peking Univ., Beijing (China)

    2000-03-01

    Flavonoid are a large and important class of naturally occurring, low molecular weight benzo-{gamma}-pyrone derivatives which are reported to have a myriad of biological activities, but the study on the active sites of flavonoids is still ambiguous. In this paper, rutin, quercetin and baicalin have been selected as model compounds. It is well known that rutin is used in inhibiting arteriosclerosis and baicalin is antibacterial and antiviral. They have similar basic structure, but their medicinal properties are so different, why? As most flavonoids contain carbonyl group, which can capture electron effectively, we predict that flavonoids can capture electron to form radical anion. The formation of anion radical may have influence on the mitochondrial electron transport chain. The difference in the ability of forming anion radical may cause the difference in their medicinal effects. (author)

  18. Structure and antimicrobial activity of phloroglucinol derivatives from Achyrocline satureioides.

    Science.gov (United States)

    Casero, Carina; Machín, Félix; Méndez-Álvarez, Sebastián; Demo, Mirta; Ravelo, Ángel G; Pérez-Hernández, Nury; Joseph-Nathan, Pedro; Estévez-Braun, Ana

    2015-01-23

    The new prenylated phloroglucinol α-pyrones 1-3 and the new dibenzofuran 4, together with the known 23-methyl-6-O-demethylauricepyrone (5), achyrofuran (6), and 5,7-dihydroxy-3,8-dimethoxyflavone (gnaphaliin A), were isolated from the aerial parts of Achyrocline satureioides. Their structures were determined by 1D and 2D NMR spectroscopic studies, while the absolute configuration of the sole stereogenic center of 1 was established by vibrational circular dichroism measurements in comparison to density functional theory calculated data. The same (S) absolute configuration of the α-methylbutyryl chain attached to the phloroglucinol nucleus was assumed for compounds 2-6 based on biogenetic considerations. Derivatives 7-16 were prepared from 1 and 5, and the antimicrobial activities of the isolated metabolites and some of the semisynthetic derivatives against a selected panel of Gram-positive and Gram-negative bacteria, as well as a set of yeast molds, were determined.

  19. [Efficacy of benzopyrones in posttraumatic inflammations/Clinical double blind study in the postoperative treatment of episiotomy (author's transl)].

    Science.gov (United States)

    Pethö, A

    1981-01-01

    A clinical double-blind study of the effectiveness of the benzopyrone product 5.6-benzo-alpha-pyron + 3',4',7-tris-(hydroxy-ethyl)-rutin (coumarin + troxerutin, Venalot) was investigated in 560 patients following medio-lateral episiotomy. The compound was investigated at various dose levels, and its active components coumarin and troxerutin separately. It was shown that the symptoms of posttraumatic inflammation like edema, rubor around the incision wound, and posttraumatic pain as well as consumption of analgesics and the postoperative scar formation were beneficially influenced by the drug. As a guideline for dosing, 1 mg/kg/d related to the coumarin content, was calculated. The efficacy of the combination of the active compounds was superior to that found with the components applied separately. The significance of episiotomy as clinical model for posttraumatic inflammation in general is discussed and application of the benzopyrone product above all in plastic surgery is suggested.

  20. New and revisited species in Aspergillus section Nigri

    DEFF Research Database (Denmark)

    Varga, J.; Frisvad, Jens Christian; Kocsube, S.

    2011-01-01

    Four new species, Aspergillus eucalypticola, A. neoniger, A. fijiensis and A. indolo genus are described and illustrated. Aspergillus eucalypticola was isolated from Eucalyptus leaf from Australia, and is related to A. tubingensis and A. costaricaensis, but could clearly be distinguished from them...... based on either beta-tubulin or calmodulin sequence data. Aspergillus eucalypticola produced pyranonigrin A, funalenone, aurasperone B and other naphtho-gamma-pyrones. Aspergillus neoniger is also a biseriate species isolated from desert sand in Namibia, and mangrove water in Venezuela, which produces...... aurasperone B and pyranonigrin A. Aspergillus fijiensis is a uniseriate species related to A. aculeatinus, and was isolated from soil in Fiji, and from Lactuca saliva in Indonesia. This species is able to grow at 37 degrees C, and produces asperparalines and okaramins. Aspergillus indologenus was isolated...

  1. Aspergillus brasiliensis sp. nov., a biseriate black Aspergillus species with world-wide distribution

    DEFF Research Database (Denmark)

    Varga, János; Kocsubé, Sándor; Tóth, Beáta

    2007-01-01

    A novel species, Aspergillus brasiliensis sp. nov., is described within Aspergillus section Nigri. This species can be distinguished from other black aspergilli based on intergenic transcribed region, beta-tubulin and calmodulin gene sequences, by amplified fragment length polymorphism analysis...... and by extrolite profiles. A. brasiliensis isolates produced naphtho-gamma-pyrones, tensidol A and B and pyrophen in common with Aspergiflus niger and Aspergillus tubingensis, but also several unique compounds, justifying their treatment as representing a separate species. None of the isolates were found...... to produce ochratoxin A, kotanins, funalenone or pyranonigrins. The novel species was most closely related to A. niger, and was isolated from soil from Brazil, Australia, USA and The Netherlands, and from grape berries from Portugal. The type strain of Aspergillus brasiliensis sp. nov. is CBS 101740(T) (=IM...

  2. Review of secondary metabolites and mycotoxins from the Aspergillus niger group

    DEFF Research Database (Denmark)

    Nielsen, Kristian Fog; Mogensen, Jesper Mølgaard; Johansen, Maria

    2009-01-01

    Filamentous fungi in the Aspergillus section Nigri (the black aspergilli) represent some of the most widespread food and feed contaminants known but they are also some of the most important workhorses used by the biotechnological industry. The Nigri section consists of six commonly found species...... (excluding A. aculeatus and its close relatives) from which currently 145 different secondary metabolites have been isolated and/or detected. From a human and animal safety point of view, the mycotoxins ochratoxin A (from A. carbonarius and less frequently A. niger) and fumonisin B2 (from A. niger...... since it is consistently produced by A. tubingensis (177 of 177 strains tested) and A. acidus (47 of 47 strains tested) but never by A. niger (140 strains tested). Naptho-γ-pyrones are the compounds produced in the highest quantities and are produced by all six common species in the group (A. niger 134...

  3. Review of Rhubarbs: Chemistry and Pharmacology

    Institute of Scientific and Technical Information of China (English)

    ZHENG Qing-xia; WU Hai-feng; GUO Jian; NAN Hai-jiang; CHEN Shi-lin; YANG Jun-shan; XU Xu-dong

    2013-01-01

    Rhubarb is a perennial herb belonging to the genus Rheum L.(Polygonaceae).Rhei Radix et Rhizoma (rhubarbroots and rhizomes) is one of the most popular Chinese materia medica and has been widely used for strong laxative function.About 200 compounds with six different types of skeletons (anthraquinone,anthrone,stilbene,flavonoids,acylglucoside,and pyrone) have so far been isolated from eighteen species of the genus Rheum L These constituents showed extensive pharmacological activities including cathartic,diuretic,anticancer,hepatoprotective,anti-inflammatory,and analgesic effects,as well as toxicological effects.Chemical fingerprint,LC-MS,and other analytical techniques have been used for the quality control of rhubarb.This comprehensive review summarizes the researches into the isolation,pharmacological activities,and phytochemical analysis reported since investigations began in the late 1940s.In addition,pharmacokinetic studies and clinical application of rhubarb are also discussed in present paper.

  4. Violapyrones H and I, New Cytotoxic Compounds Isolated from Streptomyces sp. Associated with the Marine Starfish Acanthaster planci

    Directory of Open Access Journals (Sweden)

    Hee Jae Shin

    2014-05-01

    Full Text Available Two new α-pyrone derivatives, violapyrones H (1 and I (2, along with known violapyrones B (3 and C (4 were isolated from the fermentation broth of a marine actinomycete Streptomyces sp. The strain was derived from a crown-of-thorns starfish, Acanthaster planci, collected from Chuuk, Federated States of Micronesia. The structures of violapyrones were elucidated by the analysis of 1D and 2D NMR and HR-ESIMS data. Violapyrones (1–4 exhibited cytotoxicity against 10 human cancer cell lines with GI50 values of 1.10–26.12 μg/mL when tested using sulforhodamine B (SRB assay. This is the first report on the cytotoxicity of violapyrones against cancer cell lines and the absolute configuration of violapyrone C.

  5. Review of Rhubarbs: Chemistry and Pharmacology

    Institute of Scientific and Technical Information of China (English)

    ZHENG; Qing-xia; WU; Hai-feng; GUO; Jian; NAN; Hai-jiang; CHEN; Shi-lin; YANG; Jun-shan; XU; Xu-dong

    2013-01-01

    Rhubarb is a perennial herb belonging to the genus Rheum L. (Polygonaceae). Rhei Radix et Rhizoma (rhubarb roots and rhizomes) is one of the most popular Chinese materia medica and has been widely used for strong laxative function. About 200 compounds with six different types of skeletons (anthraquinone, anthrone, stilbene, flavonoids, acylglucoside, and pyrone) have so far been isolated from eighteen species of the genus Rheum L. These constituents showed extensive pharmacological activities including cathartic, diuretic, anticancer, hepatoprotective, anti-inflammatory, and analgesic effects, as well as toxicological effects. Chemical fingerprint, LC-MS, and other analytical techniques have been used for the quality control of rhubarb. This comprehensive review summarizes the researches into the isolation, pharmacological activities, and phytochemical analysis reported since investigations began in the late 1940s. In addition, pharmacokinetic studies and clinical application of rhubarb are also discussed in present paper.

  6. Phenolic compounds from Anaphalis aureo-punctata

    Institute of Scientific and Technical Information of China (English)

    WU Yan-Qi; LOU Ning; LI Yu

    2003-01-01

    @@ From the ethanolic extract of the whole plant of Anaphalis aureo-punctata, a new acylated flavonoid glycoside 3-O-kaempferol-3-O-acetyl-6-O-(p-coumaroyl)-β-D-glucopyranoside (1), and five known phenolic compounds 3-O-kaempferol-6- O- ( p-coumaroyl )-β-D-glucopyranoside ( 2 ), kaempferol-3- O-β-D-glucopyranoside 3,6-(4′-hydroxystyryl)-4-methoxy-2-pyrone (4), 2H-pyran-2-one, 6-[ 2-( 4-(β-D-glucopyranosyloxy ) phenyl ) ethenyl ]-4-methoxy-( E ) (5) and 4-hydroxy-3-methoxycinnamic hexacosyl ester (6) were isolated. Their structures were established by spectral methods (UV, IR, MS, 1D, 2D-NMR). The flavonoid glycosides, 1, 2 and 3 showed markedly inhibited oxidative DNA strand breaks induced by Fenton reaction and NADH/PMS in a concentration-dependent manner.

  7. Mycotoxins from mould infested building materials.

    Science.gov (United States)

    Nielsen, K F

    2000-03-01

    Only limited documentation of non-allergenic, especially toxic reactions after inhalation of microfungal spores in water damaged buildings exists. Recently attention has been drawn to the mycotoxins as causal compounds, as some the dominating genera found in buildings are well known mycotoxin producers.Penicillium chrysogenum and A. ustus do not seem to produce any known mycotoxins when growing on building materials, whereasP. brevicompactum produces mycophenolic acid, someP. polonicum produces verrucosidin and verrucofortine,A. versicolor produces sterigmatocystins,A. niger produces nigragillin, orlandin, naphtho-γ-pyrones and tetracyclic compounds, someA. ochraceus produces ochratoxin A,Alternaria spp. produce alternariol and alternariol monomethyl ether,Chaetomium globosum produce chaetoglobosins, and finally 30-40% ofStachybotrys chartarum isolates from buildings produce macrocyclic trichothecenes and a number of other biologically active compounds.

  8. Fungi as a source of natural coumarins production.

    Science.gov (United States)

    Costa, Tania Maria; Tavares, Lorena Benathar Ballod; de Oliveira, Débora

    2016-08-01

    Natural coumarins and derivatives are compounds that occur naturally in several organisms (plant, bacteria, and fungi) consisting of fused benzene and α-pyrone rings. These compounds show high technological potential applications in agrochemical, food, pharmaceuticals, and cosmetics industries. Therefore, the need for bulk production of coumarins and the advancement of the chemical and pharmaceutical industries led to the development of synthetic coumarin. However, biotransformation process, synthetic bioengineering, metabolic engineering, and bioinformatics have proven effective in the production of natural products. Today, these biological systems are recognized as green chemistry innovation and business strategy. This review article aims to report the potential of fungi for synthesis of coumarin. These microorganisms are described as a source of natural products capable of synthesizing many bioactive metabolites. The features, classification, properties, and industrial applications of natural coumarins as well as new molecules obtained by basidiomycetes and ascomycetes fungi are reported in order to explore a topic not yet discussed in the scientific literature.

  9. Metal complexes of maltol and close analogues in medicinal inorganic chemistry.

    Science.gov (United States)

    Thompson, Katherine H; Barta, Cheri A; Orvig, Chris

    2006-06-01

    The family of hydroxypyrones and close congeners, the hydroxypyridinones, is a particularly versatile class of ligands. The most widely investigated for medicinal applications are the 3-hydroxy-4-pyrones and the 1,2- 3,2- and 3,4-hydroxypyridinones. Key features of these ligands are: a six-membered ring, with a ring N or O atom either ortho or para to a ketone group, and two ortho exocyclic oxygen atoms. Readily functionalizable, the hydroxypyrones and hydroxypyridinones allow one to achieve a range of di- and trivalent metallocomplex stabilities and can include tissue or molecular targeting features by design. Research over the past several decades has greatly expanded the array of ligands that are the subject of this critical review. Ligand applications as diverse as iron removal or supplementation, contrast agents in imaging applications, and mobilization of undesirable excess metal ions will be surveyed herein.

  10. Cytotoxicity and preliminary mode of action studies of novel 2-aryl-4-thiopyrone-based organometallics.

    Science.gov (United States)

    Schmidlehner, Melanie; Flocke, Lea S; Roller, Alexander; Hejl, Michaela; Jakupec, Michael A; Kandioller, Wolfgang; Keppler, Bernhard K

    2016-01-14

    Organometallic complexes with thiopyrone-based ligands have shown promising cytotoxic activity in vitro. To investigate the impact of the ligand backbone modification of these biologically active compounds and enhance the solubility in aqueous solution, the (thio)pyrone scaffold was modified via Suzuki-Miyaura coupling reaction and converted into corresponding organometallic Ru(ii) and Rh(iii) complexes. Characterization of the synthesized compounds was carried out by means of 1D and 2D NMR, ESI MS, and also by X-ray diffraction analysis. The stability in aqueous solution was investigated via(1)H NMR spectroscopy. Due to the close structural resemblance to flavonoids, topoisomerase inhibition, the cytotoxicity in human cancer cell lines as well as ROS generation was investigated by means of the topoisomerase II drug screening assay, the MTT assay and DCFH-DA assay, respectively.

  11. Aspects of carbon dioxide utilization

    Energy Technology Data Exchange (ETDEWEB)

    Omae, Iwao [Omae Research Laboratories, 335-23 Mizuno, Sayama, Saitama 350-1317 (Japan)

    2006-06-30

    Carbon dioxide reacts with hydrogen, alcohols, acetals, epoxides, amines, carbon-carbon unsaturated compounds, etc. in supercritical carbon dioxide or in other solvents in the presence of metal compounds as catalysts. The products of these reactions are formic acid, formic acid esters, formamides, methanol, dimethyl carbonate, alkylene carbonates, carbamic acid esters, lactones, carboxylic acids, polycarbonate (bisphenol-based engineering polymer), aliphatic polycarbonates, etc. Especially, the productions of formic acid, formic acid methyl ester and dimethylformamide with a ruthenium catalyst; dimethyl carbonate and urethanes with a dialkyltin catalyst; 2-pyrone with a nickel-phosphine catalyst; diphenyl carbonate with a lead phenoxide catalyst; the alternating copolymerization of carbon dioxide and epoxides with a zinc catalyst has attracted attentions as the industrial utilizations of carbon dioxide. The further development of these production processes is expected. (author)

  12. Catalytic conversion of carbon dioxide to valuable chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Baiker, A. [Swiss Federal Institute of Technology, Zuerich (Switzerland). Lab. of Technical Chemistry

    1999-08-01

    Fixation of carbon dioxide by using it as a C{sub 1}-building block in chemical synthesis has gained considerable interest, mainly stimulated by environmental considerations and by its abundant availability. Catalysis provides several opportunities to convert CO{sub 2} to valuable chemicals. The present state of these efforts is briefly surveyed giving special emphasis to most recent developments in heterogeneous catalysis, including the synthesis of methylmaines and formic acid derivatives. Chemicals synthesized by homogeneous catalysis mentioned are carbonates, carbamates, urethanes, lactones, pyrones, and formic acid and derivatives. Those made by heterogenous catalytic routes are: methanol, carbon monoxide and hydrogen (synthesis gas), methane, methylamine and formic acid derivatives. 70 refs., 1 fig.

  13. Metabolites from the endophytic mitosporic Dothideomycete sp. LRUB20.

    Science.gov (United States)

    Chomcheon, Porntep; Wiyakrutta, Suthep; Sriubolmas, Nongluksna; Ngamrojanavanich, Nattaya; Mahidol, Chulabhorn; Ruchirawat, Somsak; Kittakoop, Prasat

    2009-01-01

    The endophytic mitosporic Dothideomycete sp. LRUB20 was found to produce pyrone derivatives, dothideopyrones A-D (1, 3, 4, and 5), together with seven known compounds, including questin (9), asterric acid (10), methyl asterrate (11), sulochrin (12), and eugenitin (13), 6-hydroxymethyleugenitin (14), and cis, trans-muconic acid (15). Dothideopyrone D (5) and its acetate derivative 6 exhibited moderate cytotoxic activity. This is the first report on a naturally occurring muconic acid, which is commonly known as a biomarker in environments after exposure to benzene and phenol (or derivatives). Interestingly, the LRUB20 fungus could produce muconic acid in relatively high yield (47.8mg/L). The utility of endophytic fungi in the field of white biotechnology is discussed.

  14. Preparative Separation of Main Ustilaginoidins from Rice False Smut Balls by High-Speed Counter-Current Chromatography

    Directory of Open Access Journals (Sweden)

    Weibo Sun

    2016-01-01

    Full Text Available Ustilaginoidins are bis-naphtho-γ-pyrone mycotoxins isolated from the rice false smut balls (FSBs infected by the pathogen Villosiclava virens in rice spikelets on panicles. In order to obtain large amounts of pure ustilaginoidins to further evaluate their biological activities and functions, phytotoxicity on rice, security to human and animals as well as to accelerate their applications as pharmaceuticals, preparative high-speed counter-current chromatography (HSCCC was successfully applied to the isolation and purification of seven bis-naphtho-γ-pyrone mycotoxins, namely ustilaginoidins A (1, G (2, B (3, H (4, I (5, C (6, and J (7 from the ethyl acetate crude extract of rice FSBs. Both 1 and 2 were prepared by HSCCC from the low-polarity fraction of the crude extract using the two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water at the volume ratio of 6.5:3.5:5.0:5.0. Similarly, 3, 4 and 5 were prepared from the medium-polarity fraction using the system at the volume ratio of 4.0:5.0:5.0:6.0, and 6 and 7 were prepared from the higher-polarity fraction using the system at volume ratio of 3.0:5.0:4.0:6.7. A total of 6.2 mg of 1, 5.1 mg of 2, 3.9 mg of 3, 1.2 mg of 4, 5.7 mg of 5, 3.5 mg of 6, and 6.1 mg of 7 with purities of 88%, 82%, 91%, 80%, 92%, 81% and 83%, respectively, were yielded from total 62 mg fraction samples in three independent HSCCC runs. The structures of the purified ustilaginoidins were characterized by means of physicochemical and spectrometric analysis.

  15. Characterization of acid functional groups of carbon dots by nonlinear regression data fitting of potentiometric titration curves

    Science.gov (United States)

    Alves, Larissa A.; de Castro, Arthur H.; de Mendonça, Fernanda G.; de Mesquita, João P.

    2016-05-01

    The oxygenated functional groups present on the surface of carbon dots with an average size of 2.7 ± 0.5 nm were characterized by a variety of techniques. In particular, we discussed the fit data of potentiometric titration curves using a nonlinear regression method based on the Levenberg-Marquardt algorithm. The results obtained by statistical treatment of the titration curve data showed that the best fit was obtained considering the presence of five Brønsted-Lowry acids on the surface of the carbon dots with constant ionization characteristics of carboxylic acids, cyclic ester, phenolic and pyrone-like groups. The total number of oxygenated acid groups obtained was 5 mmol g-1, with approximately 65% (∼2.9 mmol g-1) originating from groups with pKa < 6. The methodology showed good reproducibility and stability with standard deviations below 5%. The nature of the groups was independent of small variations in experimental conditions, i.e. the mass of carbon dots titrated and initial concentration of HCl solution. Finally, we believe that the methodology used here, together with other characterization techniques, is a simple, fast and powerful tool to characterize the complex acid-base properties of these so interesting and intriguing nanoparticles.

  16. Aspergillus niger contains the cryptic phylogenetic species A. awamori.

    Science.gov (United States)

    Perrone, Giancarlo; Stea, Gaetano; Epifani, Filomena; Varga, János; Frisvad, Jens C; Samson, Robert A

    2011-11-01

    Aspergillus section Nigri is an important group of species for food and medical mycology, and biotechnology. The Aspergillus niger 'aggregate' represents its most complicated taxonomic subgroup containing eight morphologically indistinguishable taxa: A. niger, Aspergillus tubingensis, Aspergillus acidus, Aspergillus brasiliensis, Aspergillus costaricaensis, Aspergillus lacticoffeatus, Aspergillus piperis, and Aspergillus vadensis. Aspergillus awamori, first described by Nakazawa, has been compared taxonomically with other black aspergilli and recently it has been treated as a synonym of A. niger. Phylogenetic analyses of sequences generated from portions of three genes coding for the proteins β-tubulin (benA), calmodulin (CaM), and the translation elongation factor-1 alpha (TEF-1α) of a population of A. niger strains isolated from grapes in Europe revealed the presence of a cryptic phylogenetic species within this population, A. awamori. Morphological, physiological, ecological and chemical data overlap occurred between A. niger and the cryptic A. awamori, however the splitting of these two species was also supported by AFLP analysis of the full genome. Isolates in both phylospecies can produce the mycotoxins ochratoxin A and fumonisin B₂, and they also share the production of pyranonigrin A, tensidol B, funalenone, malformins, and naphtho-γ-pyrones. In addition, sequence analysis of four putative A. awamori strains from Japan, used in the koji industrial fermentation, revealed that none of these strains belong to the A. awamori phylospecies.

  17. Bioprospecting of Novel and Bioactive Compounds from Marine Actinomycetes Isolated from South China Sea Sediments.

    Science.gov (United States)

    Yang, Na; Song, Fuhang

    2017-09-16

    Marine actinomycetes are less investigated compared to terrestrial strains as potential sources of natural products. To date, few investigations have been performed on culturable actinomycetes associated with South China Sea sediments. In the present study, twenty-eight actinomycetes were recovered from South China Sea sediments after dereplication by traditional culture-dependent method. The 16S rRNA gene sequences analyses revealed that these strains related to five families and seven genera. Twelve representative strains possessed at least one of the biosynthetic genes coding for polyketide synthase I, II, and nonribosomal peptide synthetase. Four strains had anti-Mycobacterium phlei activities and five strains had activities against methicillin-resistant Staphylococcus aureus. 10 L-scale fermentation of strains Salinispora sp. NHF45, Nocardiopsis sp. NHF48, and Streptomyces sp. NHF86 were carried out for novel and bioactive compounds discovery. Finally, we obtained a novel α-pyrone compound from marine Nocardiopsis sp. NHF48, an analogue of paulomenol from marine Streptomyces sp. NHF86 and a new source of rifamycin B, produced by Salinispora sp. NHF45. The present study concluded that marine actinomycetes, which we isolated from South China Sea sediments, will be a suitable source for the development of novel and bioactive compounds.

  18. A preorganized metalloreceptor for alkaline earth ions showing calcium versus magnesium selectivity in water: biological activity of selected metal complexes.

    Science.gov (United States)

    Amatori, Stefano; Ambrosi, Gianluca; Fanelli, Mirco; Formica, Mauro; Fusi, Vieri; Giorgi, Luca; Macedi, Eleonora; Micheloni, Mauro; Paoli, Paola; Rossi, Patrizia

    2014-08-25

    The N,N'-bis[(3-hydroxy-4-pyron-2-yl)methyl]-N,N'-dimethylethylendiamine (Malten = L) forms the highly stable [CuH(-2)L] species in water, in which the converging maltol oxygen atoms form an electron-rich area able to host hard metal ions. When considering the alkaline earth series (AE), the [Cu(H(-2)L)] species binds all metal ions, with the exception of Mg(2+), exhibiting the relevant property to discriminate Ca(2+) versus Mg(2+) at physiological pH 7.4; the binding of the AE metal is visible to the naked eye. The stability constant values of the trinuclear [AE{Cu(H(-2)L)}2](2+) species formed reach the maximum for Ca(2+) (log K=7.7). Ca(2+) also forms a tetranuclear [Ca{Cu(H(-2)L)}]2(4+) species at a high Ca(2+) concentration. Tri- and tetranuclear calcium complexes show blue- and pink-colored crystals, respectively. [Cu(H(-2)L)] is the most active species in inducing DNA alterations. The DNA damages are compatible with its hydrolytic cleavages.

  19. Molecular evolution and sequence divergence of plant chalcone synthase and chalcone synthase-Like genes.

    Science.gov (United States)

    Han, Yingying; Zhao, Wenwen; Wang, Zhicui; Zhu, Jingying; Liu, Qisong

    2014-06-01

    Plant chalcone synthase (CHS) and CHS-Like (CHSL) proteins are polyketide synthases. In this study, we evaluated the molecular evolution of this gene family using representative types of CHSL genes, including stilbene synthase (STS), 2-pyrone synthase (2-PS), bibenzyl synthase (BBS), acridone synthase (ACS), biphenyl synthase (BIS), benzalacetone synthase, coumaroyl triacetic acid synthase (CTAS), and benzophenone synthase (BPS), along with their CHS homologs from the same species of both angiosperms and gymnosperms. A cDNA-based phylogeny indicated that CHSLs had diverse evolutionary patterns. STS, ACS, and 2-PS clustered with CHSs from the same species (late diverged pattern), while CTAS, BBS, BPS, and BIS were distant from their CHS homologs (early diverged pattern). The amino-acid phylogeny suggested that CHS and CHSL proteins formed clades according to enzyme function. The CHSs and CHSLs from Polygonaceae and Arachis had unique evolutionary histories. Synonymous mutation rates were lower in late diverged CHSLs than in early diverged ones, indicating that gene duplications occurred more recently in late diverged CHSLs than in early diverged ones. Relative rate tests proved that late diverged CHSLs had unequal rates to CHSs from the same species when using fatty acid synthase, which evolved from the common ancestor with the CHS superfamily, as the outgroup, while the early diverged lineages had equal rates. This indicated that late diverged CHSLs experienced more frequent mutation than early diverged CHSLs after gene duplication, allowing obtaining new functions in relatively short period of time.

  20. Trichoderma volatiles effecting Arabidopsis: from inhibition to protection against phytopathogenic fungi

    Directory of Open Access Journals (Sweden)

    Metwaly eRamadan

    2015-09-01

    Full Text Available Trichoderma species are present in many ecosystems and some strains have the ability to reduce the severity of plant diseases by activating various defence pathways via specific biologically active signaling molecules. Hence we investigated the effects of low molecular weight volatile compounds of Trichoderma asperellum IsmT5 on Arabidopsis thaliana. During co-cultivation of T. asperellum IsmT5 without physical contact to A. thaliana we observed smaller but vital and robust plants. The exposed plants exhibit increased trichome numbers, accumulation of defence-related compounds such as H2O2, anthocyanin, camalexin, and increased expression of defence related genes. We conclude that A. thaliana perceives the Trichoderma volatiles as stress compounds and subsequently initiates multilayered adaptations including activation of signaling cascades to withstand this environmental influence.The prominent headspace volatile of T. asperellum IsmT5 was identified to be 6-pentyl-α-pyrone, which was solely applied to A. thaliana to verify the growth and defence reactions. Most noticeable is that A. thaliana preexposed to 6PP showed significantly reduced symptoms when challenged with Botrytis cinerea and Alternaria brassicicola, indicating that defence-activated plants subsequently became more resistant to pathogen attack. Together, these results support that products that are based on Trichoderma volatiles have the potential being a useful biocontrol agent in agriculture.

  1. 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.

  2. Synthesis and transformations of 4-chromene 4-hydroxy-2-pyran-2-one and 4-chromene 4-hydroxycoumarin conjugates

    Indian Academy of Sciences (India)

    H Surya Prakash Rao; Venkata Swamy Tangeti

    2013-07-01

    The reaction of -methyl-4-(methylthio)-3-nitro-4-chromen-2-amine and its derivatives with 4-hydroxy-6-methyl-2-pyran-2-one in EtOH reflux for 5 min furnish 4-hydroxy-6-methyl-3-(2-(methylamino)-3-nitro-4-chromen-4-yl)-2-pyran-2-ones in quantitative yield. By extending EtOH reflux for 2 h, the 4-chromene 4-hydroxy-2-pyranone conjugates get converted into acetoacetyl coumarins. Similar reaction of -methyl-4-(methylthio)-3-nitro-4-chromen-2-amine and its derivatives with 4-hydroxycoumarin in EtOH reflux furnish 4-hydroxy-2'-(methylamino)-3'-nitro-2,4'-3,4'-bichromen-2-ones. In contrast to earlier system, prolonging reflux in EtOH or in -PrOH reflux the product gets transformed into trans-ethyl 3-(2-hydroxyaryl)-4-oxo-3,4-dihydro-2-furo[3,2-c]chromene-2-carboxylates. Thus, facile synthesis and characterization of 4-chromene 4-hydroxy-2-pyrone, 4-chromene 4-hydroxycoumarin conjugates, acetoacetyl coumarins and trans2,3-disubstituted dihydrofuro[3,2-c]coumarins is described.

  3. Supramolecular structure of S-(+)-marmesin-a linear dihydrofuranocoumarin

    Indian Academy of Sciences (India)

    Sanjeev Goswami; Vivek K Gupta; Ashok Sharma; B D Gupta

    2005-12-01

    The title compound, C14H14O4, a linear dihydrofuranocoumarin, was isolated from the bark of Aegle marmelos, a plant widely used in Ayurvedic system of medicine for the treatment of various ailments. The crystal structure was determined from X-ray diffraction data using direct methods. The compound crystallizes into monoclinic space group 21 with unit cell parameters: = 5.721(1) Å, = 13.810(1) Å, = 7.864(2) Å, = 100.39(1)°, = 2. The structure was refined by full-matrix least-squares to a final value of 0.0523 for 1184 observed reflections. The benzopyran moiety is perfectly planar. The dihedral angle between the pyrone and benzene rings is 0.3(1)°. The furan ring has a 2-envelope conformation. The molecules are linked by O–H…O hydrogen bonds into chains and these chains are linked into sheets by C–H…O hydrogen bonds. Further, the − stacking and C–H$\\ldots\\pi$(arene) interactions link all of the sheets into a supramolecular structure.

  4. Bacterial degradation of aminopyrine.

    Science.gov (United States)

    Blecher, H; Blecher, R; Wegst, W; Eberspaecher, J; Lingens, F

    1981-11-01

    1. Four strains of bacteria growing with aminopyrine as sole source of carbon were isolated from soil and were identified as strains of Phenylobacterium immobilis. 2. Strain M13 and strain E, the type species of Phenylobacterium immobilis (DSM 1986), which had been isolated by enrichment with chloridazon (5-amino-4-chloro-2-phenyl-2H-pyridazin-3-one) were used to investigate the bacterial degradation of aminopyrine. 3. Three metabolites were isolated and identified as: 4-(dimethylamino)-1,2-dihydro-1,5-dimethyl-2-(2,3-dihydro-2,3-dihydroxy-4,6-cyc lohexadien-1-yl)-3H-pyrazol-3-one, 4-(dimethylamino)-1,2-dihydro-1,5-dimethyl-2-(2,3-dihydroxyphenyl)-3H-pyrazol-3 -one and 4-(dimethylamino)-1,2-dihydro-1,5-dimethyl-3H-pyrazol-3-one. 4. An enzyme extract from cells of strain m13 was shown to further metabolize the catechol derivative of aminopyrine, with the formation of 2-pyrone-6-carboxylic acid. 5. Results indicate that the benzene ring of aminopyrine is the principal site of microbial metabolism.

  5. Discovery of New Chemical Entities for Old Targets: Insights on the Lead Optimization of Chromone-Based Monoamine Oxidase B (MAO-B) Inhibitors.

    Science.gov (United States)

    Reis, Joana; Cagide, Fernando; Chavarria, Daniel; Silva, Tiago; Fernandes, Carlos; Gaspar, Alexandra; Uriarte, Eugenio; Remião, Fernando; Alcaro, Stefano; Ortuso, Francesco; Borges, Fernanda

    2016-06-23

    The discovery of new chemical entities endowed with potent, selective, and reversible monoamine oxidase B inhibitory activity is a clinically relevant subject. Therefore, a small library of chromone derivatives was synthesized and screened toward human monoamine oxidase isoforms (hMAO-A and hMAO-B). The structure-activity relationships studies strengthen the importance of the amide spacer and the direct linkage of carbonyl group to the γ-pyrone ring, along with the presence of meta and para substituents in the exocyclic ring. The most potent MAO-B inhibitors were N-(3'-chlorophenyl)-4-oxo-4H-chromene-3-carboxamide (20) (IC50 = 403 pM) and N-(3',4'-dimethylphenyl)-4-oxo-4H-chromene-3-carboxamide (27) (IC50 = 669 pM), acting as competitive and noncompetitive reversible inhibitors, respectively. Computational docking studies provided insights into enzyme-inhibitor interactions and a rationale for the observed selectivity and potency. Compound 27 stands out due to its favorable toxicological profile and physicochemical properties, which pointed toward blood-brain barrier permeability, thus being a valid candidate for subsequent animal studies.

  6. New natural products identified by combined genomics-metabolomics profiling of marine Streptomyces sp. MP131-18.

    Science.gov (United States)

    Paulus, Constanze; Rebets, Yuriy; Tokovenko, Bogdan; Nadmid, Suvd; Terekhova, Larisa P; Myronovskyi, Maksym; Zotchev, Sergey B; Rückert, Christian; Braig, Simone; Zahler, Stefan; Kalinowski, Jörn; Luzhetskyy, Andriy

    2017-02-10

    Marine actinobacteria are drawing more and more attention as a promising source of new natural products. Here we report isolation, genome sequencing and metabolic profiling of new strain Streptomyces sp. MP131-18 isolated from marine sediment sample collected in the Trondheim Fjord, Norway. The 16S rRNA and multilocus phylogenetic analysis showed that MP131-18 belongs to the genus Streptomyces. The genome of MP131-18 isolate was sequenced, and 36 gene clusters involved in the biosynthesis of 18 different types of secondary metabolites were predicted using antiSMASH analysis. The combined genomics-metabolics profiling of the strain led to the identification of several new biologically active compounds. As a result, the family of bisindole pyrroles spiroindimicins was extended with two new members, spiroindimicins E and F. Furthermore, prediction of the biosynthetic pathway for unusual α-pyrone lagunapyrone isolated from MP131-18 resulted in foresight and identification of two new compounds of this family - lagunapyrones D and E. The diversity of identified and predicted compounds from Streptomyces sp. MP131-18 demonstrates that marine-derived actinomycetes are not only a promising source of new natural products, but also represent a valuable pool of genes for combinatorial biosynthesis of secondary metabolites.

  7. Chromones.

    Science.gov (United States)

    Edwards, Alan M

    2014-01-01

    The chromones are a class of chemical compounds characterised by the presence of the structure 5:6 benz-1:4-pyrone in their chemical make-up. The first chromone in clinical use, khellin, was extracted from the seeds of the plant Ammi visnaga, and had been used for centuries as a diuretic and as a smooth muscle relaxant. Its use in bronchial asthma was reported in 1947. In the 1950s, Benger's Laboratories embarked on a research programme to synthesise and develop modifications of khellin for the treatment of asthma. New compounds were screened using animal models to test the ability of the compound to prevent the anaphylactic release of histamine and SRS-A (leukotrienes) from sensitised guinea pig lung, and a human model to check the ability to reduce the bronchoconstriction induced by inhaled antigen bronchial challenge. For initial screening the human work was undertaken by Dr. R.E.C. Altounyan, who suffered from allergic bronchial asthma and was employed by Benger's Laboratories. After 8 years and more than 600 challenges using over 200 compounds, in 1965 Altounyan arrived at disodium cromoglycate (DSCG), the chromone that met the criteria of providing more than 6 h of protection. DSCG is still used today as a mast cell stabiliser. © 2014 S. Karger AG, Basel.

  8. Two polymorphs of N-(2-methoxyphenyl)-4-oxo-4H-chromone-3-carboxamide.

    Science.gov (United States)

    Gomes, Ligia R; Low, John Nicolson; Borges, Fernanda; Cagide, Fernando

    2013-08-01

    The title compound, C₁₇H₁₃NO₄, crystallizes in two polymorphic forms, each with two molecules in the asymmetric unit and in the monoclinic space group P2₁/c. All of the molecules have intramolecular hydrogen bonds involving the amide group. The amide N atoms act as donors to the carbonyl group of the pyrone and also to the methoxy group of the benzene ring. The carbonyl O atom of the amide group acts as an acceptor of the β and β' C atoms belonging to the aromatic rings. These intramolecular hydrogen bonds have a profound effect on the molecular conformation. In one polymorph, the molecules in the asymmetric unit are linked to form dimers by weak C-H∙∙∙O interactions. In the other, the molecules in the asymmetric unit are linked by a single weak C-H∙∙∙O hydrogen bond. Two of these units are linked to form centrosymmetric tetramers by a second weak C-H∙∙∙O interaction. Further interactions of this type link the molecules into chains, so forming a three-dimensional network. These interactions in both polymorphs are supplemented by π-π interactions between the chromone rings and between the chromone and methoxyphenyl rings.

  9. The crystal structures of four N-(4-halophenyl-4-oxo-4H-chromene-3-carboxamides

    Directory of Open Access Journals (Sweden)

    Ligia R. Gomes

    2015-01-01

    Full Text Available Four N-(4-halophenyl-4-oxo-4H-chromene-3-carboxamides (halo = F, Cl, Br and I, N-(4-fluorophenyl-4-oxo-4H-chromene-3-carboxamide, C16H10FNO3, N-(4-chlorophenyl-4-oxo-4H-chromene-3-carboxamide, C16H10ClNO3, N-(4-bromophenyl-4-oxo-4H-chromene-3-carboxamide, C16H10BrNO3, N-(4-iodophenyl-4-oxo-4H-chromene-3-carboxamide, C16H10INO3, have been structurally characterized. The molecules are essentially planar and each exhibits an anti conformation with respect to the C—N rotamer of the amide and a cis geometry with respect to the relative positions of the Carom—Carom bond of the chromone ring and the carbonyl group of the amide. The structures each exhibit an intramolecular hydrogen-bonding network comprising an N—H...O hydrogen bond between the amide N atom and the O atom of the carbonyl group of the pyrone ring, forming an S(6 ring, and a weak Carom—H...O interaction with the O atom of the carbonyl group of the amide as acceptor, which forms another S(6 ring. All four compounds have the same supramolecular structure, consisting of R22(13 rings that are propagated along the a-axis direction by unit translation. There is π–π stacking involving inversion-related molecules in each structure.

  10. Spectroscopic properties, NLO, HOMO-LUMO and NBO of maltol

    Science.gov (United States)

    KrishnaKumar, V.; Barathi, D.; Mathammal, R.; Balamani, J.; Jayamani, N.

    2014-03-01

    Maltol (3-hydroxy-2-methyl-4pyrone) is widely known as metal ions chelator with many practical applications in catalysis, medicine and food chemistry. The FTIR and FT-Raman spectra of maltol have been recorded in the region 4000-400 and 4000-50 cm-1, respectively. The conformational analysis, optimized geometry, frequency and intensity of the vibrational bands of maltol were obtained by the density functional theory (DFT) with complete relaxation in the potential energy surface using 6-31G* basis set. The observed and the calculated frequencies are found to be in good agreement. The 1H and 13C NMR spectra have been recorded and 1H and 13C nuclear magnetic resonance chemical shifts of the molecule were also calculated using the gauge independent atomic orbital (GIAO) method and their respective linear correlations were obtained. The electronic properties HOMO and LUMO energies were measured. Thermodynamic properties (heat capacity, entropy and enthalpy) of the title compound were calculated. The Mulliken charges, the values of electric dipole moment (μ) of the molecule were computed using DFT calculations. The first order hyperpolarizability (βo) and related properties (β, αo and Δα) of both are calculated using B3LYP/6-31G* method on the finite-field approach. The calculated first hyperpolarizability shows that the molecules are an attractive molecule for future applications in non-linear optics. The intramolecular contacts have been interpreted using Natural Bond Orbital (NBO).

  11. The versatile binding mode of transition-state analogue inhibitors of tyrosinase towards dicopper(II) model complexes: experimental and theoretical investigations.

    Science.gov (United States)

    Orio, Maylis; Bochot, Constance; Dubois, Carole; Gellon, Gisèle; Hardré, Renaud; Jamet, Hélène; Luneau, Dominique; Philouze, Christian; Réglier, Marius; Serratrice, Guy; Belle, Catherine

    2011-11-25

    We describe 2-mercaptopyridine-N-oxide (HSPNO) as a new and efficient competitive inhibitor of mushroom tyrosinase (K(IC) =3.7 μM). Binding studies of HSPNO and 2-hydroxypyridine-N-oxide (HOPNO) on dinuclear copper(II) complexes [Cu(2)(BPMP)(μ-OH)](ClO(4))(2) (1; HBPMP=2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-methylphenol) and [Cu(2)(BPEP)(μ-OH)](ClO(4))(2)) (2; HBPEP=2,6-bis{bis[2-(2-pyridyl)ethyl]aminomethyl}-4-methylphenol), known to be functional models for the tyrosinase diphenolase activity, have been performed. A combination of structural data, spectroscopic studies, and DFT calculations evidenced the adaptable binding mode (bridging versus chelating) of HOPNO in relation to the geometry and chelate size of the dicopper center. For comparison, binding studies of HSPNO and kojic acid (5-hydroxy-2-(hydroxymethyl)-4-pyrone) on dinuclear complexes were performed. A theoretical approach has been developed and validated on HOPNO adducts to compare the binding mode on the model complexes. It has been applied for HSPNO and kojic acid. Although results for HSPNO were in line with those obtained with HOPNO, thus reflecting their chemical similarity, we showed that the bridging mode was the most preferential binding mode for kojic acid on both complexes.

  12. Humic acid from Shilajit – a physico-chemical and spectroscopic characterization

    Directory of Open Access Journals (Sweden)

    SURAJ P. AGARWAL

    2010-03-01

    Full Text Available Shilajit is a blackish–brown exudation, consisting of organic substances, metal ions and minerals, from different formations, commonly found in the Himalayan region (1000–3000 m from Nepal to Kashmir. Shilajit can also be collected throughout the mountain regions in Afghanistan, Bhutan, China, Bajkal, throughout Ural, Caucasus and Altai mountains also, at altitudes between 1000 to 5000 m. The major physiological action of shilajit has been attributed to the presence of bioactive dibenzo-α-pyrones together with humic and fulvic acids, which act as carrier molecules for the active ingredients. In this work, the aim was to extract humic acid from Shilajit from various sources and characterised these humic acids based on their physicochemical properties, elemental analysis, UV/Vis and FTIR spectra, X-ray diffraction pattern and DSC thermograms. The spectral features obtained from UV/Vis, FTIR, XRD and DSC studies for samples of different origins showed a distinct similarity amongst themselves and in comparison to soil humic acids. The surfactant properties of the extracted fulvic acids were investigated by determining the effect of increasing concentration on the surface tension of water. The study demonstrated that humic acids extracted from shilajit indeed possessed surfactant properties.

  13. Production of Valuable Lipophilic Compounds by Using Three Types of Interface Bioprocesses: Solid-Liquid Interface Bioreactor, Liquid-Liquid Interface Bioreactor, and Extractive Liquid-Surface Immobilization System.

    Science.gov (United States)

    Oda, Shinobu

    2017-01-01

    Bioconversions such as enzymatic and microbial transformations are attractive alternatives to organic synthesis because of practical advantages such as resource conservation, energy efficiency, and environmentally harmonic properties. In addition, the production of secondary metabolites through microbial fermentation is also useful for manufacturing pharmaceuticals, agricultural chemicals, and aroma compounds. For microbial production of useful chemicals, the authors have developed three unique interfacial bioprocesses: a solid-liquid interface bioreactor (S/L-IBR), a liquid-liquid interface bioreactor (L/L-IBR), and an extractive liquid-surface immobilization (Ext-LSI) system. The S/L-IBR comprises a hydrophobic organic solvent (upper phase), a microbial film (middle phase), and a hydrophilic gel such as an agar plate (lower phase); the L/L-IBR and the Ext-LSI consist of a hydrophobic organic solvent (upper phase), a fungal mat with ballooned microspheres (middle phase), and a liquid medium (lower phase). All three systems have unique and practically important characteristics such as utilization of living cells, high concentration of lipophilic substrates/products in an organic phase, no requirement for aeration and agitation, efficient supply of oxygen, easy recovery of product, high regio- and stereoselectivity, and wide versatility. This paper reviews the principle, construction, characteristics, and application of these interfacial systems for producing lipophilic compounds such as useful aroma compounds, citronellol-related compounds, β-caryophyllene oxide, and 6-penty-α-pyrone.

  14. Development of a SBSE-TD method coupled to GC-MS and chemometrics for the differentiation of variety and processing conditions in peach juices.

    Science.gov (United States)

    Marsol-Vall, Alexis; Balcells, Mercè; Eras, Jordi; Canela-Garayoa, Ramon

    2018-01-15

    Peach juices of distinct varieties, namely yellow- and red-fleshed, and commercial and freshly blended were analyzed. The method used was based on Stir Bar Sorptive Extraction (SBSE) involving a polydimethylsiloxane-coated stir bar with thermal desorption (TD), followed by gas chromatography coupled to mass spectrometry (GC-MS) analysis. The resulting analytical data included 41 compounds belonging to several chemical classes, such as aldehydes, alcohols, lactones, terpenoids, fatty aldehydes, fatty acids and hydrocarbons. Furthermore, chemometric data treatment using unsupervised analysis (PCA) proved useful to classify peach juices on the basis of variety. Stepwise Linear Discriminant Analysis (SLDA) showed that a reduced number of variables (14 compounds), including lactones (6-pentyl-α-pyrone, γ-decalactone, γ-dodecalactone, and δ-dodecalactone), fatty acids (hexadecanoic acid), fatty aldehydes (tetracosanal and octacosanal), hydrocarbons (C23, C26, C27, C29, and C33), and alcohols (phytol and α-tocopherol), were necessary to classify the juice samples according to variety and processing conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Influence of environmental conditions on production of volatiles by Trichoderma atroviride in relation with the sick building syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Polizzi, Viviana [Ghent University, Faculty of Bioscience Engineering, Department of Sustainable Organic Chemistry and Technology, Coupure links 653, B-9000 Ghent (Belgium); Ghent University, Faculty of Pharmaceutical Sciences, Laboratory of Food Analysis, Harelbekestraat 72, B-9000 Ghent (Belgium); Adams, An; De Kimpe, Norbert [Ghent University, Faculty of Bioscience Engineering, Department of Sustainable Organic Chemistry and Technology, Coupure links 653, B-9000 Ghent (Belgium); Picco, Anna Maria [Pavia University, Faculty of Sciences, Department of Territorial Ecology and Environment, via S. Epifanio 14, 27100 Pavia (Italy); Adriaens, Els; Lenoir, Joke [Ghent University, Faculty of Pharmaceutical Sciences, Laboratory of Pharmaceutical Technology, Harelbekestraat 72, B-9000 Ghent (Belgium); Van Peteghem, Carlos; De Saeger, Sarah [Ghent University, Faculty of Pharmaceutical Sciences, Laboratory of Food Analysis, Harelbekestraat 72, B-9000 Ghent (Belgium)

    2011-04-15

    A Trichoderma atroviride strain was isolated from a water-damaged office and the production of microbial volatile organic compounds (MVOCs) was investigated by means of headspace solid phase microextraction GC-MS. Different growth conditions (substrate, temperature, relative humidity) were selected, resembling indoor parameters, to elucidate a possible relationship between MVOCs, produced by Trichoderma atroviride, and the Sick Building Syndrome. In general, the range of MVOCs and the emitted quantities were larger on malt extract agar (MEA) than on wallpaper and plasterboard. Particular attention was dedicated to the volatile marker 6-pentyl-2-pyrone, a compound produced in high quantities on MEA, and its mucosal irritation potency was shown in a slug mucosal irritation assay. Some compounds characteristic for growth on specific building materials were detected, e.g. 2-ethylcyclopentanone, menthone, iso-menthone and trans-p-menth-2-en-7-ol on plasterboard and 4-heptanone and 1-octen-3-ol on wallpaper. Relative humidity and substrate had a more important effect on MVOC production than temperature. (author)

  16. Metabolites of Trichoderma species isolated from damp building materials.

    Science.gov (United States)

    McMullin, David R; Renaud, Justin B; Barasubiye, Tharcisse; Sumarah, Mark W; Miller, J David

    2017-07-01

    Buildings that have been flooded often have high concentrations of Trichoderma spores in the air while drying. Inhaled spores and spore and mycelial fragments contain large amounts of fungal glucan and natural products that contribute to the symptoms associated with indoor mould exposures. In this study, we considered both small molecules and peptaibol profiles of T. atroviride, T. koningiopsis, T. citrinoviride, and T. harzianum strains obtained from damp buildings in eastern Canada. Twenty-residue peptaibols and sorbicillin-derived metabolites (1-6) including a new structure, (R)-vertinolide (1), were characterized from T. citrinoviride. Trichoderma koningiopsis produced several koninginins (7-10), trikoningin KA V, and the 11-residue lipopeptaibols trikoningin KB I and trikoningin KB II. Trichoderma atroviride biosynthesized a mixture of 19-residue trichorzianine-like peptaibols, whereas T. harzianum produced 18-residue trichokindin-like peptaibols and the 11-residue harzianin HB I that was subsequently identified from the studied T. citrinoviride strain. Two α-pyrones, 6-pentyl-pyran-2-one (11) and an oxidized analog (12), were produced by both T. atroviride and T. harzianum. Aside from exposure to low molecular weight natural products, inhalation of Trichoderma spores and mycelial fragments may result in exposure to membrane-disrupting peptaibols. This investigation contributes to a more comprehensive understanding of the biologically active natural products produced by fungi commonly found in damp buildings.

  17. Synthesis and Antimicrobial Activity of Furochromone, Benzofuran and Furocoumarin Derivatives Bearing Sulfonyl Moiety

    Directory of Open Access Journals (Sweden)

    Sadia A. Hessein

    2016-06-01

    Full Text Available New visnagin-9-sulfonamide derivatives 3 and 4a−c were synthesized through the reaction of visnagin-9-sulfonyl chloride 2 with amino compounds. Acetylation of compounds 4b and 4c gave the monoacetyl and diacetyl derivatives 5 and 6, respectively. Diazotization reaction of compound 4b afforded the corresponding benzotriazole derivative 8. Pyrazole and thiopyrimidine derivatives 9 and 10 were obtained via the opening of pyrone ring upon reaction of compound 3 with hydrazine hydrate and thiourea, respectively. In addition, hydrolysis of compound 3 with potassium hydroxide furnished the visnaginone derivative 11 which used as starting material for synthesize benzofuran derivatives 12−14 and bergaptene derivatives 15−17. The synthesized compounds were tested for antimicrobial activity. Furochromone derivatives 3, 4a−c, 5, 6 and 8 (visnagin-9-sulfonamide derivatives demonstrate moderate antibacterial and antifungal activities compared with the antibacterial and antifungal activites of the standard drugs. Benzofuran derivatives 11−14 (visnaginone derivatives showed the lowest antimicrobial activity among all the compounds investigated in this study. Furocoumarin derivatives 15a,b, 16 and 17 (furobenzopyransulfonamide [bergaptensulfonamides] are moderately active against all the tested strains. This work is licensed under a Creative Commons Attribution 4.0 International License.

  18. Characterization of the molecular degradation mechanism of diphenyl ethers by Cupriavidus sp. WS.

    Science.gov (United States)

    Wang, Sheng; Bai, Naling; Wang, Bing; Feng, Zhuo; Hutchins, William C; Yang, Ching-Hong; Zhao, Yuhua

    2015-11-01

    Commonly used flame retardants, such as polybrominated diphenyl ethers, are extremely persistent in the environment, causing serious environmental risks. Certain strains of bacteria are able to degrade several low brominated congeners of PBDEs aerobically. However, the aerobic degradation pathway is not yet well understood, particularly at the genetic level. In this study, we isolated Cupriavidus sp. WS from the environment that could degrade diphenyl ether (DE), 4-bromodiphenyl ether, and 4,4'-bromodiphenyl ether. DE was completely degraded in 6 days without any detectable end-product. Using transposon mutagenesis, several DE degradation-deficient mutants were obtained. Knocking out bphA1, bphA2, and bphA3 eliminated the ability of the Cupriavidus sp. WS bacterium to degrade DE, indicating that the bph genes play a crucial role in DE degradation by this strain. The specific roles of bphA, bphB, and bphC were identified by systematically expressing these genes in Escherichia coli. The dihydrodiol product of BphA was dehydrogenated into 2,3-dihydroxydiphenyl ether by BphB. 2,3-Dihydroxydiphenyl ether was then decomposed into phenol and 2-pyrone-6-carboxylic acid by BphC. Thus, BphA, BphB, and BphC act sequentially in the aerobic degradation of DE, 4-bromodiphenyl ether, and 4,4'-dibromodiphenyl ether by the Cupriavidus sp. WS bacterium.

  19. Immunomodulatory Effects of Esculetin (6,7-Dihydroxycoumarin) on Murine Lymphocytes and Peritoneal Macrophages

    Institute of Scientific and Technical Information of China (English)

    Kwok-nam Leung; Pui-yin Leung; Lai-ping Kong; Po-ki Leung

    2005-01-01

    Coumarins belong to a diverse group of naturally occurring non-nutrient phytochemicals known as benzo-α-pyrones. In this study, esculetin, a 6,7-dihydroxy derivative of coumarin with pleiotropic biological activities, was found to have no significant cytotoxic effect on normal murine macrophages, but it could increase the in vivo migration of the thioglycollate-elicited macrophages in a dose-dependent manner. Moreover, esculetin significantly increased the endocytic activity, and augmented the nitric oxide production and iNOS gene expression in LPS-treated macrophages. In addition, in vivo administration of esculetin into mice was shown to increase the mitogenesis of splenic lymphocytes towards Con A and LPS stimulations, and induced the LAK activity of splenic lymphocytes. Collectively, our results indicate that esculetin could exert immunomodulatory effects on murine macrophages and lymphocytes, both in vitro and in vivo, and this might be one of the possible mechanisms by which coumarins can exert their chemopreventive and anti-tumor activities in vivo.

  20. New Constituents from the Fresh Stems of Opuntia Dillenii%仙人掌肉质茎中的新化学成份

    Institute of Scientific and Technical Information of China (English)

    邱鹰昆; 陈英杰; 裴玉萍; 松田久司; 吉川雅之

    2003-01-01

    Aim To study the chemical composition of Opuntia dillenii Haw. Methods Many kinds of chromatography methods were used in the isolation procedure, while the structures of isolated compounds were determined on the aids ofNMR and MS spectral analysis. Result Three new compounds, together with 14 known compounds, were isolated form the80% ethanolic extract of its stems. Conclusion The three new compounds, opuntioside I (2), 4-ethoxyl-6-hydroxymethyl-α-pyrone (3) and kaempferol 7-O-β- D-glucopyranosyl (1→4)-β-D- glucopyranoside (4), were characterized.%目的研究仙人掌的化学成分.方法应用多种柱色谱方法进行分离和纯化,NMR和MS等波谱解析化学结构.结果从仙人掌肉质茎80%乙醇提取物分离得到3个新化合物,14个已知化合物.结论化合物2、3、4为新化合物,分别命名为:仙人掌苷Ⅰ,4-乙氧基-6-羟甲基-α-吡喃酮及山奈酚7-O-β-D-吡喃葡萄糖基(1→4)-β-D-吡喃葡萄糖苷.

  1. PEEK: An excellent precursor for activated carbon production for high temperature application

    Energy Technology Data Exchange (ETDEWEB)

    Cansado, I.P.P.; Goncalves, F.A.M.M.; Nabais, J.M.V.; Ribeiro Carrott, M.M.L.; Carrott, P.J.M. [Centro de Quimica de Evora and Departamento de Quimica, Universidade de Evora, Colegio Luis Antonio Verney, 7000-671 Evora (Portugal)

    2009-02-15

    A series of activated carbons (AC) with high apparent surface area and very high micropore volumes were prepared from granulated PEEK (poly[oxy-1,4-phenylene-oxy-1,4-phenylene-carbonyl-1,4-phenylene]) by physical activation with CO{sub 2} at different temperatures and different activation times. The carbonisation yields at 873, 1073 and 1173 K were 57, 52 and 51%. As the activation temperature increased, between 873 and 1173 K, the burn-off, the micropore volume and mean pore size increased too. Those prepared at 1173 K, with 74% burn-off, present an extremely high apparent surface area (2874 m{sup 2} g{sup -} {sup 1}) and a very high micropore volume (1.27 cm{sup 3} g{sup -} {sup 1}). The presence of pyrone groups, identified by FTIR, on the AC surface corroborates the prevalence of a basic point of zero charge, always higher than 9.2. The thermal stability was checked by thermogravimetric analysis and as the carbonisation temperature increased the thermal stability of the char increased too. All AC obtained from PEEK by physical activation at 1173 K are thermally resistant, as at 1073 K the loss of the initial mass was less than 15%. The collective results confirm that PEEK is an excellent precursor for preparing AC with a high carbonisation yield, a high micropore volume and apparent surface area and a very high resistance at elevated temperature. (author)

  2. Empirical valence bond models for reactive potential energy surfaces: a parallel multilevel genetic program approach.

    Science.gov (United States)

    Bellucci, Michael A; Coker, David F

    2011-07-28

    We describe a new method for constructing empirical valence bond potential energy surfaces using a parallel multilevel genetic program (PMLGP). Genetic programs can be used to perform an efficient search through function space and parameter space to find the best functions and sets of parameters that fit energies obtained by ab initio electronic structure calculations. Building on the traditional genetic program approach, the PMLGP utilizes a hierarchy of genetic programming on two different levels. The lower level genetic programs are used to optimize coevolving populations in parallel while the higher level genetic program (HLGP) is used to optimize the genetic operator probabilities of the lower level genetic programs. The HLGP allows the algorithm to dynamically learn the mutation or combination of mutations that most effectively increase the fitness of the populations, causing a significant increase in the algorithm's accuracy and efficiency. The algorithm's accuracy and efficiency is tested against a standard parallel genetic program with a variety of one-dimensional test cases. Subsequently, the PMLGP is utilized to obtain an accurate empirical valence bond model for proton transfer in 3-hydroxy-gamma-pyrone in gas phase and protic solvent.

  3. [Adsorption mechanism of furfural onto modified rice husk charcoals].

    Science.gov (United States)

    Deng, Yong; Wang, Xianhua; Li, Yunchao; Shao, Jing'ai; Yang, Haiping; Chen, Hanping

    2015-10-01

    To evaluate the absorptive characteristics of furfural onto biomass charcoals derived from rice husk pyrolysis, we studied the information of the structure and surface chemistry properties of the rice husk charcoals modified by thermal treatment under nitrogen and carbon dioxide flow and adsorption mechanism of furfural. The modified samples are labeled as RH-N2 and RH-CO2. Fresh rice husk charcoal sample (RH-450) and modified samples were characterized by elemental analysis, nitrogen adsorption-desorption isotherms, Fourier-transform infrared spectroscopy and Boehm titration. The results show that fresh rice husk charcoal obtained at 450 degrees C had a large number of organic groups on its surface and poor pore structure. After the modification under nitrogen and carbon dioxide flow, oxygenic organics in rice husk charcoals decompose further, leading to the reduction of acidic functional groups on charcoals surface, and the increase of the pyrone structures of the basic groups. Meanwhile, pore structure was improved significantly and the surface area was increased, especially for the micropores. This resulted in the increase of π-π dispersion between the surfaces of rice husk charcoals and furfural molecular. With making comprehensive consideration of π-π dispersion and pore structure, the best removal efficiency of furfural was obtained by rice husk charcoal modified under carbon dioxide flow.

  4. Transcription profiling of the Neurospora crassa response to a group of synthetic (thioxanthones and a natural acetophenone

    Directory of Open Access Journals (Sweden)

    A. Pedro Gonçalves

    2015-06-01

    Full Text Available Xanthones are a class of heterocyclic compounds characterized by a dibenzo-γ-pyrone nucleus. Analysis of their mode of action in cells, namely uncovering alterations in gene expression, is important because these compounds have potential therapeutic applications. Thus, we studied the transcriptional response of the filamentous fungus Neurospora crassa to a group of synthetic (thioxanthone derivatives with antitumor activity using high throughput RNA sequencing. The induction of ABC transporters in N. crassa, particularly atrb and cdr4, is a common consequence of the treatment with xanthones. In addition, we found a group of genes repressed by all of the tested (thioxanthone derivatives, that are evocative of genes downregulated during oxidative stress. The transcriptional response of N. crassa treated with an acetophenone isolated from the soil fungus Neosartorya siamensis shares some features with the (thioxanthone-elicited gene expression profiles. Two of the (thioxanthone derivatives and the N. siamensis-derived acetophenone inhibited the growth of N. crassa. Our work also provides framework datasets that may orientate future studies on the mechanisms of action of some groups of xanthones.

  5. Co-culturing of Pichia guilliermondii enhanced volatile flavor compound formation by Zygosaccharomyces rouxii in the model system of Thai soy sauce fermentation.

    Science.gov (United States)

    Wah, Thin Thin; Walaisri, Supawan; Assavanig, Apinya; Niamsiri, Nuttawee; Lertsiri, Sittiwat

    2013-01-01

    The roles of salt-tolerant yeasts such as Zygosaccharomyces rouxii, Candida versatilis, and Candida etchellsii in the production of volatile flavor compounds (VFCs) in soy sauce fermentation have been well documented. However, the knowledge of VFC production by other salt-tolerant yeasts is still limited. In this work, the roles of Z. rouxii and Pichia guilliermondii strains in VFC production were investigated in moromi medium as a model system for soy sauce fermentation. Inoculation of a single culture of either Z. rouxii or P. guilliermondii as well as co-cultures of these two yeasts into moromi medium showed increased numbers of viable yeast at around 0.7 to 1.9 log CFU/mL after 7days of cultivation at 30°C. During cultivation, both single and co-cultures displayed survival over a 7-day time period, compared with the controls (no culture added). Overall, yeast inoculation enhanced the production of VFCs in the moromi media with higher amounts of ethanol, alcohols, furanones, esters, aldehyde, acid, pyrone and phenols, known as important characteristic flavor compounds in soy sauce. Moreover, the co-culture produced more alcohols, furanones, esters, maltol and benzoic acid than the single culture of Z. rouxii.

  6. Synergism of Antifungal Activity between Mitochondrial Respiration Inhibitors and Kojic Acid

    Directory of Open Access Journals (Sweden)

    Ronald P. Haff

    2013-01-01

    Full Text Available Co-application of certain types of compounds to conventional antimicrobial drugs can enhance the efficacy of the drugs through a process termed chemosensitization. We show that kojic acid (KA, a natural pyrone, is a potent chemosensitizing agent of complex III inhibitors disrupting the mitochondrial respiratory chain in fungi. Addition of KA greatly lowered the minimum inhibitory concentrations of complex III inhibitors tested against certain filamentous fungi. Efficacy of KA synergism in decreasing order was pyraclostrobin > kresoxim-methyl > antimycin A. KA was also found to be a chemosensitizer of cells to hydrogen peroxide (H2O2, tested as a mimic of reactive oxygen species involved in host defense during infection, against several human fungal pathogens and Penicillium strains infecting crops. In comparison, KA-mediated chemosensitization to complex III inhibitors/H2O2 was undetectable in other types of fungi, including Aspergillus flavus, A. parasiticus, and P. griseofulvum, among others. Of note, KA was found to function as an antioxidant, but not as an antifungal chemosensitizer in yeasts. In summary, KA could serve as an antifungal chemosensitizer to complex III inhibitors or H2O2 against selected human pathogens or Penicillium species. KA-mediated chemosensitization to H2O2 seemed specific for filamentous fungi. Thus, results indicate strain- and/or drug-specificity exist during KA chemosensitization.

  7. New Butyrolactone Type Lignans from Arctii Fructus and Their Anti-inflammatory Activities.

    Science.gov (United States)

    Yang, Ya-Nan; Huang, Xiao-Ying; Feng, Zi-Ming; Jiang, Jian-Shuang; Zhang, Pei-Cheng

    2015-09-16

    Arctiidilactone (1), a novel rare butyrolactone lignan with a 6-carboxyl-2-pyrone moiety, and 11 new butyrolactone lignans (2-12) were isolated from the fruits of Arctium lappa L., together with 5 known compounds (13-17). Their structures were elucidated by interpretation of their spectroscopic data (1D and 2D NMR, UV, IR, ORD, and HRESIMS) and comparison to literature data. The absolute configurations of compounds 1-12 were determined by a combination of rotating-frame nuclear Overhauser effect spectroscopy (ROESY), circular dichroism (CD) spectroscopy, and Rh2(OCOCF3)4-induced CD spectroscopy. All of the compounds were tested for their anti-inflammatory properties in terms of suppressing the production of NO in lipopolysaccharide-induced BV2 cells. Compounds 1, 6, 8, and 10 exhibited stronger anti-inflammatory effects than the positive control curcumin, particularly 1, which exhibited 75.51, 70.72, and 61.17% inhibition at 10, 1, and 0.1 μM, respectively.

  8. HARNESSING THE CHEMISTRY OF CO2

    Energy Technology Data Exchange (ETDEWEB)

    Louie, Janis

    2010-05-11

    Our research program is broadly focused on activating CO{sub 2} through the use of organic and organometallic based catalysts. Some of our methods have centered on annulation reactions of unsaturated hydrocarbons (and carbonyl substrates) to provide a diverse array of carbocycles and heterocycles. We use a combination of catalyst discovery and optimization in conjunction with classical physical organic chemistry to elucidate the key mechanistic features of the cycloaddition reactions such that the next big advances in catalyst development can be made. Key to all of our cycloaddition reactions is the use of a sterically hindered, electron donating N heterocyclic carbene (NHC) ligand, namely IPr (or SIPr), in conjunction with a low valent nickel pre-catalyst. The efficacy of this ligand is two-fold: (1) the high {delta}-donating ability of the NHC increases the nucleophilicity of the metal center which thereby facilitates interaction with the electrophilic carbonyl and (2) the steric hindrance prevents an otherwise competitive side reaction involving only the alkyne substrate. Such a system has allowed for the facile cycloaddition to prepare highly functionalized pyrones, pyridones, pyrans, as well as novel carbocycles. Importantly, all reactions proceed under extremely mild conditions (room temperature, atmospheric pressures, and short reaction times), require only catalytic amounts of Ni/NHC and readily available starting materials, and afford annulated products in excellent yields. Our current focus revolves around understanding the fundamental processes that govern these cycloadditions such that the next big advance in the cyclization chemistry of CO{sub 2} can be made. Concurrent to our annulation chemistry is our investigation of the potential for imidazolylidenes to function as thermally-actuated CO{sub 2} sequestering and delivery agents.

  9. New insights in the discovery of novel h-MAO-B inhibitors: structural characterization of a series of N-phenyl-4-oxo-4H-chromene-3-carboxamide derivatives

    Directory of Open Access Journals (Sweden)

    Ligia R. Gomes

    2015-05-01

    Full Text Available Six N-substituted-phenyl 4-oxo-4H-chromene-3-carboxamides, namely N-(2-nitrophenyl-4-oxo-4H-chromene-3-carboxamide, C16H10N2O5 (2b, N-(3-methoxyphenyl-4-oxo-4H-chromene-3-carboxamide, C17H13NO4, (3a, N-(3-bromophenyl-4-oxo-4H-chromene-3-carboxamide, C16H10BrNO3, (3b, N-(4-methoxyphenyl-4-oxo-4H-chromene-3-carboxamide, C17H13NO4, (4a, N-(4-methylphenyl-4-oxo-4H-chromene-3-carboxamide, C17H13NO3, (4d, and N-(4-hydroxyphenyl-4-oxo-4H-chromene-3-carboxamide, C16H11NO4, (4e, have been structurally characterized. All compounds exhibit an anti conformation with respect to the C—N rotamer of the amide and a trans-related conformation with the carbonyl groups of the chromone ring of the amide. These structures present an intramolecular hydrogen-bonded network comprising an N—H...O hydrogen bond between the amide N atom and the O atom of the carbonyl group of the pyrone ring, forming an S(6 ring, and a weak Car—H...O hydrogen bond in which the carbonyl group of the amide acts as acceptor for the H atom of an ortho-C atom of the exocyclic phenyl ring, which results in another S(6 ring. The N—H...O intramolecular hydrogen bond constrains the carboxamide moiety such that it is virtually coplanar with the chromone ring.

  10. Gênero Acosmium: composição química e potencial farmacológico Acosmium genus: chemical composition and pharmacological potential

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    Paulo T. Sousa Júnior

    2009-03-01

    Full Text Available O gênero Acosmium possui 17 espécies com distribuição geográfica que se estende do sudeste do México até o Nordeste da Argentina, sendo que a maioria das espécies está localizada no Brasil. A. dasycarpum, A. panamense, A. subelegans são as espécies mais utilizadas popularmente no tratamento de enfermidades. Uma busca na literatura, resguardando aspectos químicos e farmacológicos destas plantas, indicam atividade citotóxica, ação antitérmica, efeito hipoglicêmico, bem como tem sido usada no tratamento da doença de Alzheimer e desordens no sistema nervoso central. Investigação fitoquímica resultou principalmente no isolamento de terpenos, ácido cafêico, alcalóides do tipo diaza-adamantano e quinolizidínicos bem como pironas.The genus Acosmium is composed by c.a. 17 species, with geographic distribution from southeastern Mexico to Northwestern Argentina. Most of the species, however, are located in Brazil. A. dasycarpum, A. panamense, A. subelegans are used in folk medicine to treat several ailments. A search in the literature regarding the chemical and pharmacological aspects of these plants indicates cytotoxic activity, antithermal and hypoglycemic effects, as well as their use to treat Alzheimer's disease and CNS disorders. Phytochemical investigations resulted mainly in the isolation of terpenes, caffeic acid, diaza-adamantane and quinolizidines alkaloids as well as pyrones.

  11. Enhanced Production of Botrallin and TMC-264 with in Situ Macroporous Resin Adsorption in Mycelial Liquid Culture of the Endophytic Fungus Hyalodendriella sp. Ponipodef12

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    Haiyu Luo

    2014-09-01

    Full Text Available Hyalodendriella sp. Ponipodef12, an endophytic fungus from the hybrid “Neva” of Populus deltoides × P. nigra, is a high producer of the bioactive dibenzo-α-pyrones botrallin and TMC-264. However, both the botrallin and TMC-264 produced by Hyalodendriella sp. Ponipodef12 were retained as both intracellular and extracellular products. The aim of this study was to evaluate an in situ macroporous resin adsorption for enhancement of botrallin and TMC-264 production in mycelial liquid culture of Hyalodendriella sp. Ponipodef12. Production of botrallin and TMC-264 was most effectively enhanced by macroporous resin DM-301 among the thirteen nonionic macroporous resins tested. The highest botrallin yield (51.47 mg/L, which was 2.29-fold higher than the control at 22.49 mg/L was obtained by adding resin DM-301 at 4.38% (g/mL to the culture broth on day 24 and allowing a period of 4 days for adsorption. The highest TMC-264 yield reached 47.74 mg/L, which was 11.76-fold higher than that of the control (4.06 mg/L, and was achieved by adding DM-301 resin at 4.38% (w/v in the culture broth on day 24 and allowing a period of 6 days for adsorption. The results show that in situ resin adsorption is an effective strategy for enhancing production of botrallin and TMC-264, and also for facilitating their recovery from mycelial liquid culture of Hyalodendriella sp. Ponipodef12.

  12. New natural products isolated from Metarhizium robertsii ARSEF 23 by chemical screening and identification of the gene cluster through engineered biosynthesis in Aspergillus nidulans A1145.

    Science.gov (United States)

    Kato, Hiroki; Tsunematsu, Yuta; Yamamoto, Tsuyoshi; Namiki, Takuya; Kishimoto, Shinji; Noguchi, Hiroshi; Watanabe, Kenji

    2016-07-01

    To rapidly identify novel natural products and their associated biosynthetic genes from underutilized and genetically difficult-to-manipulate microbes, we developed a method that uses (1) chemical screening to isolate novel microbial secondary metabolites, (2) bioinformatic analyses to identify a potential biosynthetic gene cluster and (3) heterologous expression of the genes in a convenient host to confirm the identity of the gene cluster and the proposed biosynthetic mechanism. The chemical screen was achieved by searching known natural product databases with data from liquid chromatographic and high-resolution mass spectrometric analyses collected on the extract from a target microbe culture. Using this method, we were able to isolate two new meroterpenes, subglutinols C (1) and D (2), from an entomopathogenic filamentous fungus Metarhizium robertsii ARSEF 23. Bioinformatics analysis of the genome allowed us to identify a gene cluster likely to be responsible for the formation of subglutinols. Heterologous expression of three genes from the gene cluster encoding a polyketide synthase, a prenyltransferase and a geranylgeranyl pyrophosphate synthase in Aspergillus nidulans A1145 afforded an α-pyrone-fused uncyclized diterpene, the expected intermediate of the subglutinol biosynthesis, thereby confirming the gene cluster to be responsible for the subglutinol biosynthesis. These results indicate the usefulness of our methodology in isolating new natural products and identifying their associated biosynthetic gene cluster from microbes that are not amenable to genetic manipulation. Our method should facilitate the natural product discovery efforts by expediting the identification of new secondary metabolites and their associated biosynthetic genes from a wider source of microbes.

  13. The application of psoralens to the study of DNA structure, function and dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Spielmann, P.H. [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry]|[Lawrence Berkeley Lab., CA (United States)

    1991-04-01

    A series of six nitroxide spin-labeled psoralens were designed, synthesized and tested as probes for DNA dynamics. The synthesis of these spin-labeled psoralen derivatives and their photoreactivity with double-stranded DNA fragments is described. The spin labels (nitroxides) were demonstrated to survive the uv irradiation required to bind the probe to the target DNA. EPR spectra of the photobound spin-labels indicate that they do not wobble with respect to the DNA on the time-scales investigated. The author has used psoralen modified DNA as a model for the study of DNA repair enzyme systems in human cell free extracts. He has shown that damage-induced DNA synthesis is associated with removal of psoralen adducts and therefore is {open_quotes}repair synthesis{close_quotes} and not an aberrant DNA synthesis reaction potentiated by deformation of the DNA by adducts. He has found that all DNA synthesis induced by psoralen monoadducts is the consequence of removal of these adducts. By the same approach he has obtained evidence that this in vitro system is capable of removing psoralen cross-links as well. Reported here are synthetic methods that make use of high intensity lasers coupled with HPLC purification to make homogeneous and very pure micromole quantities of furan-side monoadducted, cross-linked, and pyrone-side monoadducted DNA oligonucleotide. These molecules are currently being studied by NMR and X-ray crystallography. The application of the site-specifically psoralen modified oligonucleotide synthesized by these methods to the construction of substrates for the investigation of DNA repair is also discussed.

  14. New non-toxic transition metal nanocomplexes and Zn complex-silica xerogel nanohybrid: Synthesis, spectral studies, antibacterial, and antitumor activities

    Science.gov (United States)

    Shebl, Magdy; Saif, M.; Nabeel, Asmaa I.; Shokry, R.

    2016-08-01

    A new chromone Schiff base and its complexes of Cu(II), Ni(II), Co(II), Fe(III), Zn(II), Cd(II), and UO2(VI) as well as Zn(II) complex-silica xerogel nanohybrid were successfully prepared in a nano domain with crystalline or amorphous structures. Structures of the Schiff base and its complexes were investigated by elemental and thermal analyses, IR, 1H NMR, electronic, ESR, mass spectra, XRD, and TEM, as well as conductivity and magnetic susceptibility measurements. The spectroscopic data revealed that the Schiff base ligand behaves as a monobasic tridentate ligand. The coordination sites with metal ions are γ-pyrone oxygen, azomethine nitrogen, and oxygen of the carboxylic group. The metal complexes exhibited octahedral geometry, except Cu(II) complex, which has a square planar geometry and UO2(VI) complex, in which uranium ion is hepta-coordinated. Transmission electron microscope (TEM) analysis showed that Ni(II) and Zn(II) complexes have aggregated spheres and rod morphologies, respectively. TEM images of Zn(II) complex-silica xerogel nanohybrid showed a nanosheet morphology with 46 nm average size and confirmed that the complex was uniformly distributed into the silica pores. The obtained nanocomplexes were tested as antimicrobial and antitumor agents. The results showed that Zn(II) nanocomplex and Zn(II) complex-silica xerogel nanohybrid have high activity. The toxicity test on mice showed that Zn(II) complex and Zn(II) complex-silica xerogel nanohybrid have lower toxicity than cisplatin.

  15. Synthesis, Spectral Characterization, Molecular Modeling, and Antimicrobial Studies of Cu(II, Ni(II, Co(II, Mn(II, and Zn(II Complexes of ONO Schiff Base

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    Padmaja Mendu

    2012-01-01

    Full Text Available A series of Cu(II, Ni(II, Co(II, Mn(II, and Zn(II complexes have been synthesized from the schiff base ligand L. The schiff base ligand [(4-oxo-4H-chromen-3-yl methylene] benzohydrazide (L has been synthesized by the reaction between chromone-3-carbaldehyde and benzoyl hydrazine. The nature of bonding and geometry of the transition metal complexes as well as schiff base ligand L have been deduced from elemental analysis, FT-IR, UV-Vis, 1HNMR, ESR spectral studies, mass, thermal (TGA and DTA analysis, magnetic susceptibility, and molar conductance measurements. Cu(II, Ni(II, Co(II, and Mn(II metal ions are forming 1:2 (M:L complexes, Zn(II is forming 1:1 (M:L complex. Based on elemental, conductance and spectral studies, six-coordinated geometry was assigned for Cu(II, Ni(II, Co(II, Mn(II, and Zn(II complexes. The complexes are 1:2 electrolytes in DMSO except zinc complex, which is neutral in DMSO. The ligand L acts as tridentate and coordinates through nitrogen atom of azomethine group, oxygen atom of keto group of γ-pyrone ring and oxygen atom of hydrazoic group of benzoyl hydrazine. The 3D molecular modeling and energies of all the compounds are furnished. The biological activity of the ligand and its complexes have been studied on the four bacteria E. coli, Edwardella, Pseudomonas, and B. subtilis and two fungi pencillium and tricoderma by well disc and fusion method and found that the metal chelates are more active than the free schiff base ligand.

  16. Revealing the biotechnological potential of Delftia sp. JD2 by a genomic approach

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    María A. Morel

    2016-04-01

    Full Text Available Delftia sp. JD2 is a chromium-resistant bacterium that reduces Cr(VI to Cr(III, accumulates Pb(II, produces the phytohormone indole-3-acetic acid and siderophores, and increases the plant growth performance of rhizobia in co-inoculation experiments. We aimed to analyze the biotechnological potential of JD2 using a genomic approach. JD2 has a genome of 6.76Mb, with 6,051 predicted protein coding sequences and 93 RNA genes (tRNA and rRNA. The indole-acetamide pathway was identified as responsible for the synthesis of indole-3-acetic acid. The genetic information involved in chromium resistance (the gene cluster, chrBACF, was found. At least 40 putative genes encoding for TonB-dependent receptors, probably involved in the utilization of siderophores and biopolymers, and genes for the synthesis, maturation, exportation and uptake of pyoverdine, and acquisition of Fe-pyochelin and Fe-enterobactin were also identified. The information also suggests that JD2 produce polyhydroxybutyrate, a carbon reserve polymer commonly used for manufacturing petrochemical free bioplastics. In addition, JD2 may degrade lignin-derived aromatic compounds to 2-pyrone-4,6-dicarboxylate, a molecule used in the bio-based polymer industry. Finally, a comparative genomic analysis of JD2, Delftia sp. Cs1-4 and Delftia acidovorans SPH-1 is also discussed. The present work provides insights into the physiology and genetics of a microorganism with many potential uses in biotechnology.

  17. Rare actinomycetes Nocardia caishijiensis and Pseudonocardia carboxydivorans as endophytes, their bioactivity and metabolites evaluation.

    Science.gov (United States)

    Tanvir, Rabia; Sajid, Imran; Hasnain, Shahida; Kulik, Andreas; Grond, Stephanie

    2016-04-01

    Two strains identified as Nocardia caishijiensis (SORS 64b) and Pseudonocardia carboxydivorans (AGLS 2) were isolated as endophytes from Sonchus oleraceus and Ageratum conyzoides respectively. The analysis of their extracts revealed them to be strongly bioactive. The N. caishijiensis extract gave an LC50 of 570 μg/ml(-1) in the brine shrimp cytotoxicity assay and an EC50 of 0.552 μg/ml(-1) in the DPPH antioxidant assay. Antimicrobial activity was observed against Methicillin resistant Staphlococcus aureus (MRSA) and Escherichia coli ATCC 25922 (14 mm), Klebsiella pneumoniae ATCC 706003 (13 mm), S. aureus ATCC 25923 (11 mm) and Candida tropicalis (20 mm). For the extract of P. carboxydivorans the EC50 was 0.670 μg/ml(-1) and it was observed to be more bioactive against Bacillus subtilis DSM 10 ATCC 6051 (21 mm), C. tropicalis (20 mm), S. aureus ATCC 25923 (17 mm), MRSA (17 mm), E. coli K12 (W1130) (16 mm) and Chlorella vulgaris (10 mm). The genotoxicity testing revealed a 20 mm zone of inhibition against the polA mutant strain E. coli K-12 AB 3027 suggesting damage to the DNA and polA genes. The TLC and bioautography screening revealed a diversity of active bands of medium polar and nonpolar compounds. Metabolite analysis by HPLC-DAD via UV/vis spectral screening suggested the possibility of stenothricin and bagremycin A in the mycelium extract of N. caishijiensis respectively. In the broth and mycelium extract of P. carboxydivorans borrelidin was suggested along with α-pyrone. The HPLC-MS revealed bioactive long chained amide derivatives such as 7-Octadecenamide, 9, 12 octadecandienamide. This study reports the rare actinomycetes N. caishijiensis and P. carboxydivorans as endophytes and evaluates their bioactive metabolites.

  18. Challenges in identifying sites climatically matched to the native ranges of animal invaders.

    Science.gov (United States)

    Rodda, Gordon H; Jarnevich, Catherine S; Reed, Robert N

    2011-02-09

    Species distribution models are often used to characterize a species' native range climate, so as to identify sites elsewhere in the world that may be climatically similar and therefore at risk of invasion by the species. This endeavor provoked intense public controversy over recent attempts to model areas at risk of invasion by the Indian Python (Python molurus). We evaluated a number of MaxEnt models on this species to assess MaxEnt's utility for vertebrate climate matching. Overall, we found MaxEnt models to be very sensitive to modeling choices and selection of input localities and background regions. As used, MaxEnt invoked minimal protections against data dredging, multi-collinearity of explanatory axes, and overfitting. As used, MaxEnt endeavored to identify a single ideal climate, whereas different climatic considerations may determine range boundaries in different parts of the native range. MaxEnt was extremely sensitive to both the choice of background locations for the python, and to selection of presence points: inclusion of just four erroneous localities was responsible for Pyron et al.'s conclusion that no additional portions of the U.S. mainland were at risk of python invasion. When used with default settings, MaxEnt overfit the realized climate space, identifying models with about 60 parameters, about five times the number of parameters justifiable when optimized on the basis of Akaike's Information Criterion. When used with default settings, MaxEnt may not be an appropriate vehicle for identifying all sites at risk of colonization. Model instability and dearth of protections against overfitting, multi-collinearity, and data dredging may combine with a failure to distinguish fundamental from realized climate envelopes to produce models of limited utility. A priori identification of biologically realistic model structure, combined with computational protections against these statistical problems, may produce more robust models of invasion risk.

  19. Mycobacterial F420H2-Dependent Reductases Promiscuously Reduce Diverse Compounds through a Common Mechanism

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    Chris Greening

    2017-05-01

    Full Text Available An unusual aspect of actinobacterial metabolism is the use of the redox cofactor F420. Studies have shown that actinobacterial F420H2-dependent reductases promiscuously hydrogenate diverse organic compounds in biodegradative and biosynthetic processes. These enzymes therefore represent promising candidates for next-generation industrial biocatalysts. In this work, we undertook the first broad survey of these enzymes as potential industrial biocatalysts by exploring the extent, as well as mechanistic and structural bases, of their substrate promiscuity. We expressed and purified 11 enzymes from seven subgroups of the flavin/deazaflavin oxidoreductase (FDOR superfamily (A1, A2, A3, B1, B2, B3, B4 from the model soil actinobacterium Mycobacterium smegmatis. These enzymes reduced compounds from six chemical classes, including fundamental monocycles such as a cyclohexenone, a dihydropyran, and pyrones, as well as more complex quinone, coumarin, and arylmethane compounds. Substrate range and reduction rates varied between the enzymes, with the A1, A3, and B1 groups exhibiting greatest promiscuity. Molecular docking studies suggested that structurally diverse compounds are accommodated in the large substrate-binding pocket of the most promiscuous FDOR through hydrophobic interactions with conserved aromatic residues and the isoalloxazine headgroup of F420H2. Liquid chromatography-mass spectrometry (LC/MS and gas chromatography-mass spectrometry (GC/MS analysis of derivatized reaction products showed reduction occurred through a common mechanism involving hydride transfer from F420H- to the electron-deficient alkene groups of substrates. Reduction occurs when the hydride donor (C5 of F420H- is proximal to the acceptor (electrophilic alkene of the substrate. These findings suggest that engineered actinobacterial F420H2-dependent reductases are promising novel biocatalysts for the facile transformation of a wide range of α,β-unsaturated compounds.

  20. DNA damage and repair kinetics of the Alternaria mycotoxins alternariol, altertoxin II and stemphyltoxin III in cultured cells.

    Science.gov (United States)

    Fleck, Stefanie C; Sauter, Friederike; Pfeiffer, Erika; Metzler, Manfred; Hartwig, Andrea; Köberle, Beate

    2016-03-01

    The Alternaria mycotoxins alternariol (AOH) and altertoxin II (ATX II) have previously been shown to elicit mutagenic and genotoxic effects in bacterial and mammalian cells, although with vastly different activities. For example, ATX II was about 50 times more mutagenic than AOH. We now report that stemphyltoxin III (STTX III) is also highly mutagenic. The more pronounced effects of the perylene quinones ATX II and STTX III at lower concentrations compared to the dibenzo-α-pyrone AOH indicate a marked dependence of the genotoxic potential on the chemical structure and furthermore suggest that the underlying modes of action may be different. We have now further investigated the type of DNA damage induced by AOH, ATX II and STTX III, as well as the repair kinetics and their dependence on the status of nucleotide excision repair (NER). DNA double strand breaks induced by AOH due to poisoning of topoisomerase IIα were completely repaired in less than 2h. Under cell-free conditions, inhibition of topoisomerase IIα could also be measured for ATX II and STTX III at low concentrations, but the perylene quinones were catalytic inhibitors rather than topoisomerase poisons and did not induce DSBs. DNA strand breaks induced by ATX II and STTX III were more persistent and not completely repaired within 24h. A dependence of the repair rate on the NER status could only be demonstrated for STTX III, resulting in an accumulation of DNA damage in NER-deficient cells. Together with the finding that the DNA glycosylase formamidopyrimidine-DNA glycosylase (Fpg), but not T4 endonuclease V, is able to generate additional DNA strand breaks measurable by the alkaline unwinding assay, we conclude that the genotoxicity of the perylene quinones with an epoxide group is probably caused by the formation of DNA adducts which may be converted to Fpg sensitive sites.

  1. A Novel and Effective Streptomyces sp. N2 Against Various Phytopathogenic Fungi.

    Science.gov (United States)

    Xu, Bo; Chen, Wei; Wu, Zhi-ming; Long, Yue; Li, Kun-tai

    2015-11-01

    Phytopathogenic fungi would induce a variety of plant diseases, resulting in a severe reduction of agricultural output. However, the current plant disease control is mainly dependent on the environmentally and healthily hazardous chemical fungicides. Thus, the present work aimed to isolate an effective antagonistic microorganism against various soilborne phytopathogenic fungi. By dual culture with Rhizoctonia solani, a novel Streptomyces specie, Streptomyces sp. N2, was screened out from a total of 167 isolated actinomycetes, which displayed a strong inhibitory effect on R. solani (26.85 ± 1.35 mm of inhibition zone diameter). By means of macroporous resin and silica gel column chromatography coupled with preparative HPLC, an antifungal metabolite (3-methyl-3,5-amino-4-vinyl-2-pyrone, C6H7O2N) was isolated and purified from Streptomyces sp. N2. The bioassay results showed that the purified antifungal metabolite could not only possess a broad-spectrum inhibitory effect on a range of plant pathogenic fungi in vitro (e.g., R. solani, Pyricularia grisea, Fusarium oxysporum f. sp. niveum, F. oxysporum f. sp. vasinfectum, Penicillium italicum, and Colletotrichum gloeosporioides), but also had a significantly effective in vivo biocontrol efficacy on grape fruits anthracnose caused by C. gloeosporioides. Microscopic observation indicated that the antifungal metabolite from Streptomyces sp. N2 would exert its antimicrobial activity by disorganizing the cytoplasmic organelles of phytopathogenic fungi. The above results suggested that Streptomyces sp. N2 was one of promising fungicide for biocontrol of fungal plant diseases, especially due to its broad-spectrum and effective antagonist on various plant pathogens.

  2. Gulypyrones A and B and Phomentrioloxins B and C Produced by Diaporthe gulyae, a Potential Mycoherbicide for Saffron Thistle (Carthamus lanatus).

    Science.gov (United States)

    Andolfi, Anna; Boari, Angela; Evidente, Marco; Cimmino, Alessio; Vurro, Maurizio; Ash, Gavin; Evidente, Antonio

    2015-04-24

    A virulent strain of Diaporthe gulyae, isolated from stem cankers of sunflower and known to be pathogenic to saffron thistle, has been shown to produce both known and previously undescribed metabolites when grown in either static liquid culture or a bioreactor. Together with phomentrioloxin, a phytotoxic geranylcyclohexenetriol recently isolated from a strain of Phomopsis sp., two new phytotoxic trisubstituted α-pyrones, named gulypyrones A and B (1 and 2), and two new 1,O- and 2,O-dehydro derivatives of phomentrioloxin, named phomentrioloxins B and C (3 and 4), were isolated from the liquid culture filtrates of D. gulyae. These four metabolites were characterized as 6-[(2S)2-hydroxy-1-methylpropyl]-4-methoxy-5-methylpyran-2-one (1), 6-[(1E)-3-hydroxy-1-methylpropenyl]-4-methoxy-3-methylpyran-2-one (2), 4,6-dihydroxy-5-methoxy-2-(7-methyl-3-methyleneoct-6-en-1-ynyl)cyclohex-2-enone (3), and 2,5-dihydroxy-6-methoxy-3-(7-methyl-3-methyleneoct-6-en-1-ynyl)cyclohex-3-enone (4) using spectroscopic and chemical methods. The absolute configuration of the hydroxylated secondary carbon of the 2-hydroxy-1-methylpropyl side chain at C-6 of gulypyrone A was determined as S by applying a modified Mosher's method. Other well-known metabolites were also isolated including 3-nitropropionic, succinic, and p-hydroxy- and p-methylbenzoic acids, p-hydroxybenzaldehyde, and nectriapyrone. When assayed using a 5 mM concentration on punctured leaf disks of weedy and crop plants, apart from 3-nitropropionic acid (the main metabolite responsible for the strong phytotoxicity of the culture filtrate), phomentrioloxin B caused small, but clear, necrotic spots on a number of plant species, whereas gulypyrone A caused leaf necrosis on Helianthus annuus plantlets. All other compounds were weakly active or inactive.

  3. Actividad antioxidante de esteroles y ácidos orgánicos naturales

    Directory of Open Access Journals (Sweden)

    Mastro-Durán, R.

    1993-06-01

    Full Text Available This paper deals with antioxidant activity of sterols and natural organic acids not covered on previous papers. The paper «Antioxidant activity of phenolic compounds» covered phenolic acids; the second one «Antioxidant activity of vitamin C, D and provitamin A», ascorbic acid, and the third «Antioxidant activity of natural nitrogenous compounds», aminoacids. The acids studied here included citric, malic, lactic, fumarle, tartaric, kojic (5-hydroxy-2-[hydroxymethyl-γ-pyrone], phytic (inositol-hexaphosphoric acid and furoic acids. The reaction mechanisms, either as inhibitors of the chain reaction of prooxidant radicals or by sequestration of free radicals was discussed. Finally, a list of recent patents of these compounds and their derivatives as antioxidants or synergists was included.

    Actividad antioxidante de esteroles y ácidos orgánicos naturales. Continuando el estudio de los antioxidantes naturales, se incluyen en este trabajo los esteroles y los ácidos orgánicos no estudiados en los trabajos anteriores (ácidos fenólicos, en «Actividad antioxidante de los compuestos fenólicos»: ácido ascórbico, en «Actividad antioxidante de las vitaminas C y D y de la provitamina A», aminoácidos, en «Actividad antioxidante de compuestos naturales nitrogenados». Los ácidos orgánicos cuya actividad como antioxidantes se estudia en este trabajo son: cítrico, málico, láctico, fumárico, sórbico, tartárico, kójico, fítico y furoicos. Se discuten sus mecanismos de reacción en cadena de los radicales prooxidantes, bien por secuestro de estos radicales. Finalmente, se citan las patentes registradas en los últimos años por estos compuestos o sus derivados como antioxidantes o como sinergistas con otros productos.

  4. A novel approach to recycle bacterial culture waste for fermentation reuse via a microbial fuel cell-membrane bioreactor system.

    Science.gov (United States)

    Li, Jian; Zhu, Yuan; Zhuang, Liangpeng; Otsuka, Yuichiro; Nakamura, Masaya; Goodell, Barry; Sonoki, Tomonori; He, Zhen

    2015-09-01

    Biochemical production processes require water and nutrient resources for culture media preparation, but aqueous waste is generated after the target products are extracted. In this study, culture waste (including cells) produced from a lab-scale fermenter was fed into a microbial fuel cell-membrane bioreactor (MFC-MBR) system. Electrical energy was generated via the interaction between the microbial consortia and the solid electrode in the MFC. The treated wastewater was reclaimed in this process which was reused as a solvent and a nutrient source in subsequent fermentation. Polarization testing showed that the MFC produced a maximum current density of 37.53 A m(-3) with a maximum power density of 5.49 W m(-3). The MFC was able to generate 0.04 kWh of energy per cubic meter of culture waste treated. The lab-scale fermenters containing pure cultures of an engineered Pseudomonas spp. were used to generate 2-pyrone-4,6-dicarboxylic acid (PDC), a high value platform chemical. When the MFC-MBR-treated wastewater was used for the fermenter culture medium, a specific bacterial growth rate of 1.00 ± 0.05 h(-1) was obtained with a PDC production rate of 708.11 ± 64.70 mg PDC L(-1) h(-1). Comparable values for controls using pure water were 0.95 ± 0.06 h(-1) and 621.01 ± 22.09 mg PDC L(-1) h(-1) (P > 0.05), respectively. The results provide insight on a new approach for more sustainable bio-material production while at the same time generating energy, and suggest that the treated wastewater can be used as a solvent and a nutrient source for the fermentation production of high value platform chemicals.

  5. Identification of the Products of Oxidation of Quercetin by Air Oxygenat Ambient Temperature

    Directory of Open Access Journals (Sweden)

    Viktor A Utsal

    2007-03-01

    Full Text Available Oxidation of quercetin by air oxygen takes place in water and aqueous ethanol solutions under mild conditions, namely in moderately-basic media (pH ∼ 8-10 at ambient temperature and in the absence of any radical initiators, without enzymatic catalysis or irradiation of the reaction media by light. The principal reaction products are typical of other oxidative degradation processes of quercetin, namely 3,4-dihydroxy-benzoic (proto-catechuic and 2,4,6-trihydroxybenzoic (phloroglucinic acids, as well as the decarboxylation product of the latter – 1,3,5-trihydroxybenzene (phloroglucinol. In accordance with the literature data, this process involves the cleavage of the γ-pyrone fragment (ring C of the quercetin molecule by oxygen, with primary formation of 4,6-dihydroxy-2-(3,4-dihydroxybenzoyloxybenzoic acid (depside. However under such mild conditions the accepted mechanism of this reaction (oxidative decarbonylation with formation of carbon monoxide, CO should be reconsidered as preferably an oxidative decarboxylation with formation of carbon dioxide, CO2. Direct head-space analysis of the gaseous components formed during quercetin oxidation in aqueous solution at ambient temperature indicates that the ratio of carbon dioxide/carbon monoxide in the gas phase after acidification of the reaction media is ca. 96:4 %. Oxidation under these mild conditions is typical for other flavonols having OH groups at C3 (e.g., kaempferol, but it is completely suppressed if this hydroxyl group is substituted by a glycoside fragment (as in rutin, or a methyl substituent. An alternative oxidation mechanism involving the direct cleavage of the C2-C3 bond in the diketo-tautomer of quercetin is proposed.

  6. Simultaneous qualitative and quantitative determination of phenolic compounds in Aloe barbadensis Mill by liquid chromatography-mass spectrometry-ion trap-time-of-flight and high performance liquid chromatography-diode array detector.

    Science.gov (United States)

    Wu, Xiaofang; Ding, Wenjing; Zhong, Jiasheng; Wan, Jinzhi; Xie, Zhiyong

    2013-06-01

    An effective and comprehensive method was developed for the simultaneous analysis of phenolic compounds in the dried exudate of Aloe barbadensis Mill by liquid chromatography-mass spectrometry-ion trap-time-of-flight (LCMS-IT-TOF) and high performance liquid chromatography-diode array detector (HPLC-DAD). Qualitative analysis of all the compounds presented in A. barbadensis Mill was performed on LCMS-IT-TOF, and the diagnostic fragmentation patterns of different types of phenolic compounds (chromones, phenyl pyrones, naphthalene derivative, anthrones and anthraquinones) were discussed on the basis of ESI-IT-TOF MS of components in A. barbadensis Mill and eleven authentic standards. Under the optimal HPLC-DAD chromatographic conditions, quantification of 11 typical phenolic compounds in 15 batches of A. barbadensis Mill was achieved on an Agilent TC-C18 column using gradient elution with a solvent system of methanol and water at a flow rate of 1.0mLmin(-1) and detected at 230nm. All calibration curves exhibited good linear relationship (r(2)>0.9991). The relative standard deviation values for intraday precision were less than 2% with accuracies between 98.21% and 104.57%. The recoveries of the eleven analytes ranged from 97.53 to 105.00% with RSDs less than 2%. This is the first simultaneous characterization and quantitative determination of multiple phenolic compounds in A. barbadensis Mill from locally grown cultivars in China by LCMS-IT-TOF and HPLC-DAD, which can be applied to standardize the quality of A. barbadensis Mill and the future design of nutraceutical and cosmetic preparations.

  7. Genetic localization and in vivo characterization of a Monascus azaphilone pigment biosynthetic gene cluster.

    Science.gov (United States)

    Balakrishnan, Bijinu; Karki, Suman; Chiu, Shih-Hau; Kim, Hyun-Ju; Suh, Jae-Won; Nam, Bora; Yoon, Yeo-Min; Chen, Chien-Chi; Kwon, Hyung-Jin

    2013-07-01

    Monascus spp. produce several well-known polyketides such as monacolin K, citrinin, and azaphilone pigments. In this study, the azaphilone pigment biosynthetic gene cluster was identified through T-DNA random mutagenesis in Monascus purpureus. The albino mutant W13 bears a T-DNA insertion upstream of a transcriptional regulator gene (mppR1). The transcription of mppR1 and the nearby polyketide synthase gene (MpPKS5) was significantly repressed in the W13 mutant. Targeted inactivation of MpPKS5 also gave rise to an albino mutant, confirming that mppR1 and MpPKS5 belong to an azaphilone pigment biosynthetic gene cluster. This M. purpureus sequence was used to identify the whole biosynthetic gene cluster in the Monascus pilosus genome. MpPKS5 contains SAT/KS/AT/PT/ACP/MT/R domains, and this domain organization is preserved in other azaphilone polyketide synthases. This biosynthetic gene cluster also encodes fatty acid synthase (FAS), which is predicted to assist the synthesis of 3-oxooactanoyl-CoA and 3-oxodecanoyl-CoA. These 3-oxoacyl compounds are proposed to be incorporated into the azaphilone backbone to complete the pigment biosynthesis. A monooxygenase gene (an azaH and tropB homolog) that is located far downstream of the FAS gene is proposed to be involved in pyrone ring formation. A homology search on other fungal genome sequences suggests that this azaphilone pigment gene cluster also exists in the Penicillium marneffei and Talaromyces stipitatus genomes.

  8. The Genus Aloe: Phytochemistry and Therapeutic Uses Including Treatments for Gastrointestinal Conditions and Chronic Inflammation.

    Science.gov (United States)

    Cock, I E

    2015-01-01

    Plants of the genus Aloe have perhaps the longest recorded history of medicinal usage and are amongst the most widely used plants for traditional medicinal purposes worldwide. Aloe vera, Aloe ferox, Aloe arborescens and Aloe perryi are the best known and most widely used, but many other species are also used for their therapeutic properties. The Aloes have been used since ancient times, particularly for the treatment of microbial infections, gastrointestinal disorders and inflammatory conditions. In addition to their myriad uses in traditional therapeutics, the Aloes have also been used as components of cosmetic formulations, and in the food and beverage industries. Despite their wide acceptance, studies from different laboratories often report wide variations in the therapeutic bioactivities from within the same Aloe species, even when the same extraction procedures are used. Furthermore, leaves from individual Aloe plants within the same species may have widely varying levels of the bioactive phytochemicals. Phytochemical analyses have shown that many Aloe species contain various carbohydrate polymers (notably glucomannans) and a range of other low molecular weight phenolic compounds including alkaloids, anthraquinones, anthrones, benzene and furan derivatives, chromones, coumarins, flavonoids, phytosterols, pyrans and pyrones. There has been a wealth of information published about the phytochemistry and therapeutic potential of the Aloes (especially Aloe vera). Much of this has been contradictory. Intra- and interspecies differences in the redox state of the individual Aloe components and in the ratios of these components may occur between individual plants. These factors may all affect the physiological properties of Aloe extracts. Due to the structure and chemical nature of many of the Aloe phytochemicals, it is likely that many of the reported medicinal properties are due to antioxidant or prooxidant effects. The antioxidant/prooxidant activities of many Aloe

  9. 猴头菌液体静置发酵液的化学成分与细胞毒活性%Chemical Components from Surface Liquid Fermented Hericium erinaceus with Cytotoxity Investigations

    Institute of Scientific and Technical Information of China (English)

    郑永标; 鲁春华; 许莉; 郑忠辉; 苏文金; 沈月毛

    2012-01-01

    Hericium erinaceus was cultured by surface liquid fermentation with Potato-Dextose medium. The fermented solution was extracted and purified by repeated column chromatography (RP-18, Sephadex LH-20 and silica gel) to afford six chemical components. Based on the NMR and ESI MS data,the structures of the six components were elucidated as erinacine P (1) , orsellinaldehyde ( 2) , herierin IV ( 3 ) , erinapyrone A ( 4 ) , erinapyrone B ( 5) and erinapyrone C ( 6). Erinacine P (1) was isolated from the fermented solution of H. erinaceus for the first time and it showed high bioac-tivity in the MTT assay against HeLa cells. Orsellinaldehyde (2) ,named 2,4-dihydroxy-6-methylbenzaldehyde,was separated from H. erinaceus for the first time. Herierin IV (3) .erinapyrone A (4) ,erinapyrone B (5) and erinapyrone C (6) were all the pyrone derivatives.%以马铃薯葡萄糖为培养基进行猴头菌液体静置发酵.利用萃取、中压液相色谱(RP-18 gel)、凝胶柱层析(Sephadex LH-20)和硅胶柱层析(Silica gel)从其发酵液中分离并结构鉴定了6个化合物.经核磁共振波谱解析与质谱鉴定,确定化合物的结构为Erinacine P(1)、Orsellinaldehyde (2)、Herierin IV (3)、Erinapyrone A(4)、Erinapyrone B(5)和Erinapyrone C(6).Erinacine P (1)为首次从猴头菌发酵液中分离获得的二萜糖苷化合物,MTT实验表明其具有较强的细胞毒活性.Orsellinaldehyde (2)为首次从猴头菌中分离到的苯甲醛衍生物.Herierin IV (3)、Erinapyrone A(4)、Erinapyrone B(5)和Erinapyrone C(6)为4个吡喃酮衍生物.

  10. Domain analysis of 3 Keto Acyl-CoA synthase for structural variations in Vitis vinifera and Oryza brachyantha using comparative modelling.

    Science.gov (United States)

    Sagar, Mamta; Pandey, Neetesh; Qamar, Naseha; Singh, Brijendra; Shukla, Akanksha

    2015-03-01

    The long chain fatty acids incorporated into plant lipids are derived from the iterative addition of C2 units which is provided by malonyl-CoA to an acyl-CoA after interactions with 3-ketoacyl-CoA synthase (KCS), found in several plants. This study provides functional characterization of three 3 ketoacyl CoA synthase like proteins in Vitis vinifera (one) and Oryza brachyantha (two proteins). Sequence analysis reveals that protein of Oryza brachyantha shows 96% similarity to a hypothetical protein in Sorghum bicolor; total 11 homologs were predicted in Sorghum bicolor. Conserved domain prediction confirm the presence of FAE1/Type III polyketide synthase-like protein, Thiolase-like, subgroup; Thiolase-like and 3-Oxoacyl-ACP synthase III, C-terminal and chalcone synthase like domain but very long chain 3-keto acyl CoA domain is absent. All three proteins were found to have Chalcone and stilbene synthases C terminal domain which is similar to domain of thiolase and β keto acyl synthase. Its N terminal domain is absent in J3M9Z7 protein of Oryza brachyantha and F6HH63 protein of Vitis vinifera. Differences in N-terminal domain is responsible for distinguish activity. The J3MF16 protein of Oryza brachyantha contains N terminal domain and C terminal domain and characterized using annotation of these domains. Domains Gcs (streptomyces coelicolor) and Chalcone-stilbene synthases (KAS) in 2-pyrone synthase (Gerbera hybrid) and chalcone synthase 2 (Medicago sativa) were found to be present in three proteins. This similarity points toward anthocyanin biosynthetic process. Similarity to chalcone synthase 2 reveals its possible role in Naringenine and Chalcone synthase like activity. In 3 keto acyl CoA synthase of Oryza brachyantha. Active site residues C-240, H-407, N-447 are present in J3MF16 protein that are common in these three protein at different positions. Structural variations among dimer interface, product binding site, malonyl-CoA binding sites, were predicted in

  11. The use of heterogeneous chemistry for the characterization of functional groups at the gas/particle interface of soot and TiO2 nanoparticles.

    Science.gov (United States)

    Setyan, A; Sauvain, J-J; Rossi, M J

    2009-08-07

    Six gases [N(CH(3))(3), NH(2)OH, CF(3)COOH, HCl, NO(2) and O(3)] were selected to probe the surface of seven different types of combustion aerosol samples (amorphous carbon, flame soot) and three types of TiO(2) nanoparticles using heterogeneous, i.e. gas-surface reactions. The gas uptake to saturation of the probes was measured under molecular flow conditions in a Knudsen flow reactor and expressed as a density of surface functional groups on a particular aerosol, namely acidic (carboxylic) and basic (conjugated oxides such as pyrone, N-heterocycle and amine) sites, carbonyl (R(1)-C(O)-R(2)) and oxidizable (olefinic, -OH) groups. The limit of detection was generally well below 1% of a formal monolayer of adsorbed probe gas. With few exceptions most investigated aerosol samples interacted with all probe gases to various extents which points to the coexistence of different functional groups on the same aerosol surface such as acidic and basic groups. Generally, the carbonaceous particles displayed significant differences in surface group density: Printex 60 amorphous carbon had the lowest density of surface functional groups throughout, whereas Diesel soot recovered from a Diesel particulate filter had the largest. The presence of basic oxides on carbonaceous aerosol particles was inferred from the ratio of uptakes of CF(3)COOH and HCl owing to the larger stability of the acetate compared to the chloride counterion in the resulting pyrylium salt. Both soots generated from a rich and a lean hexane diffusion flame had a large density of oxidizable groups similar to amorphous carbon FS 101. TiO(2) 15 had the lowest density of functional groups studied for all probe gases among the three TiO(2) nanoparticles despite the smallest size of its primary particles. The technique used enabled the measurement of the uptake probability of the probe gases on the various supported aerosol samples. The initial uptake probability, gamma(0), of the probe gas onto the supported

  12. Anti-inflammatory properties of dietary flavonoids Propiedades antiinflamatorias de los flavonoides de la dieta

    Directory of Open Access Journals (Sweden)

    J. González-Gallego

    2007-06-01

    Full Text Available Flavonoids are a group of natural substances that are located in sources of vegetal origin. More than 4,000 varieties of flavonoids have been identified. All of them are phenyl-benzopyrones of low molecular weight with a basic structure formed by two benzene rings united through a heterocyclic pyrane or pyrone. Besides their relevance in plants, flavonoids are important for human health. Their antioxidant capacity confers a therapeutic potential in cardiovascular diseases, gastric or duodenal ulcers, cancer or hepatic pathologies. Also important are their antiviral and anti-allergic actions, as well as their anti-thrombotic and anti-inflammatory properties. Prostaglandins and nitric oxide biosynthesis is involved in inflammation, and isoforms of inducible nitric oxide synthase (iNOS and of cyclooxygenase (COX-2 are responsible for the production of a great amount of these mediators. It has been demonstrated that flavonoids are able to inhibit both enzymes, as well as other mediators of the inflammatory process such as reactive C protein or adhesion molecules. Modulation of the cascade of molecular events leading to the overexpression of those mediators include inhibition of transcription factors such as nuclear factor kappa B and AP-1, through the inhibition of protein kinases involved in signal transduction. Increased antioxidant defenses through activation of the NF-E2 related factor 2 (Nrf2 also contribute to the anti-inflammatory capacity of flavonoidsLos flavonoides son un grupo de las sustancias naturales que se encuentran en fuentes de origen vegetal, existiendo más de 4.000 variedades. Todos son fenilbenzopironas de peso molecular bajo con una estructura básica formada por dos anillos heterocíclicos de benceno unidos a través de un pirano o de una pirona. Además de su función en las plantas, los flavonoides son importantes para la salud humana. Su capacidad antioxidante confiere un potencial terapéutico en enfermedades

  13. Quality evaluation of decocting pieces of Juemingzi (Semen Casiae) based on processing principle%基于炒制原理的决明子饮片质量评价研究

    Institute of Scientific and Technical Information of China (English)

    李丽; 张村; 肖永庆

    2011-01-01

    Objective To study the quality evaluation method of decocting pieces of Juemingzi (Semen Casiae) based on the processing principle of the decocting pieces. Methods The study on the quality evaluation standard for the crude pieces and stir-fried pieces of Juemingzi was conducted based on the quality identification by TCL and HPLC fingerprints and quantitative determination according to the significant changes of 5 constituents before and after processing. Results The method of TLC taken buranol-acetic acid-water as opening system was used simply and intuitively in the identification of the crude pieces and stir-fried pieces of Juemingzi. The changes of main chemical compositions of decocting pieces of Juemingzi before and after processing were reflected by 2 fingerprints of detecting wavelength and content changes of 2 naphtha-pyrone glycosides and 3 anthraquinone aglycons. Conclusion After processing, the internal material basis will change essentially in decocting pieces. The quality evaluation standard should be established and perfected gradually, which is identified by traditional experience combining with quality determination of fingerprints, quantitative determination of multi-index constituents and characters of decocting pieces aiming at the scientific evaluation of different processing products of the same Chinese medicinal.%目的 基于决明子炒制原理,研究决明子饮片的质量评价方法.方法 以薄层层析法(TLC)及高效液相色谱法(HPLC)指纹图谱定性鉴别5个炮制前后变化显著的成分定量,进行决明子生、炒饮片的质量评价标准研究.结果 以正丁醇-冰醋酸-水为展开系统的TLC鉴别方法,可以简便、直观地用于生、炒决明子饮片的鉴别.决明子饮片2个检测波长的指纹图谱,2个萘并吡喃酮苷及3个蒽醌苷元的含量变化均可反映出饮片炮制前后主要化学成分的变化情况.结论 中药饮片炮制后,其内在物质基础发生了本质的改变,

  14. Redox System of Cerium(Ⅳ)-Flavonoids and Applications%Ce(Ⅵ)与6种天然黄酮化合物的氧化还原体系及其应用

    Institute of Scientific and Technical Information of China (English)

    龚双梅; 李晓波; 张荣荣; 赵良容; 杨昌英

    2011-01-01

    Six different natural flavonoids with similar structures, quercetin, kaempferol, luteolin, naringenin, baicalein, and apigenin were selected to examine the redox system between flavonoids and Ce ( IV ) using ultraviolet spectrophotometry and microtitration methods. According to their responding difference to Ce( IV) , the mechanism of the reaction and the contribution of phenolic hydroxyls on different sites of the chromone to the antioxidation activity were investigated. The result indicates that the 3-OH of the pyrone ring is a sensitive site to react with Ce( IV) involving the proton dissociation, and the obtained product has a strong absorbance at 294 nm. The 3'-OH and 4'-OH on the B ring of the 2-phenyl-chromone are also the sensitive sites to oxidants since 4'-0H dissociates and forms intramolecular hydrogen bonding. The hydroxyl on ring C is more sensitive to Ce( IV) than that on ring A. The antioxidant capacity order of the six compounds is: Quercetin > Kaempferol > Luteoin > Apigenin > Baicalein > Naringenin, which is consistent with the sensitivity of spectral response of the six compounds to Ce(Ⅳ).%选取结构相近的6种天然黄酮化合物:槲皮素( Quercetin)、山奈酚(Kaempferol)、木犀草素(Luteolin)、柚皮素(Naringenin)、黄芩素(Baicalein)和芹菜素(Apigenin),利用紫外可见分光光度法,结合微量滴定手段,追踪并记录了6种黄酮化合物与Ce(Ⅳ)形成的氧化还原体系的紫外吸收信号,根据化合物对Ce(Ⅳ)响应差异,探讨了不同位置酚羟基对化合物抗氧化活性的贡献及作用机制.结果表明,色原酮C环上3-OH首先与Ce(Ⅳ)作用,发生质子解离而氧化,其氧化产物在294 nm产生较强的吸收峰,3′,4′邻位—OH有利于在氧化剂Ce(Ⅳ)存在时4′羟基解离形成分子内氢键,紫外吸收光谱带Ⅱ的双峰会明显分离.其它位置的酚羟基也会对Ce(Ⅳ)产生响应,且C环上的羟基比A环上的更灵敏.同时,低浓度的黄酮会引起Ce