The Catalytic Enantioselective Total Synthesis of (+)-Liphagal

KAUST Repository

Day, Joshua J.

2011-06-10

Ring a ding: The meroterpenoid natural product (+)-liphagal has been synthesized enantioselectively in 19 steps from commercially available materials. The trans-homodecalin system was achieved by ring expansion followed by stereoselective hydrogenation. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The asymmetric total synthesis of (+)- and (-)-trypargine via Noyori asymmetric transfer hydrogenation

International Nuclear Information System (INIS)

Pilli, Ronaldo A.; Rodrigues Junior, Manoel Trindade

2009-01-01

A concise and efficient total synthesis of (+)- and (-)-trypargine (6 steps and 38% overall yield), a 1-substituted β-carboline guanidine alkaloid isolated from the skin of the African frog K. senegalensis, was developed based on the construction of the b-carboline moiety via Bischler-Napieralski reaction and the enantioselective reduction of the dihydro-β-carboline intermediate via an asymmetric transfer hydrogenation reaction using Noyori's protocol. (author)

[Contents mensuration of total alkaloid in Uncaria rhynchophylla by acid dye colorimetry].

Science.gov (United States)

Zeng, Chang-qing; Luo, Bei-liang

2007-08-01

To investigate the method of determination of total alkaloids Uncaria rhynchophylla. The Contents of total Alkaloid were determined by Acid dye Colorimetry. Acid dye color conditions: pH3.6 buffer 5.0 ml, bromocresol green liquid 5.0 ml; chloroform extraction three times, each time was exeracted for 2 minutes, put it aside for at least 5 minutes for the determination of the best method. Rhynchophylline 6.018 microg - 108.324 microg in the linear range, Recoveriys rate was 97.19%, RSD was 1.34% (n = 6). The method is simple, highly sensitive and reproducible.

Proof of concept for continuous enantioselective liquid-liquid extraction in capillary microreactors using 1-octanol as a sustainable solvent

NARCIS (Netherlands)

Susanti, S.; Meinds, Tim G.; Pinxterhuis, Erik B.; Schuur, Boelo; De Vries, Johannes G.; Feringa, Ben L.; Winkelman, Jozef G.M.; Yue, Jun; Heeres, Hero J.

2017-01-01

The use of capillary microreactors for enantioselective liquid-liquid extraction (ELLE) was successfully demonstrated using a model system consisting of a buffered aqueous amino acid derivative (3,5-dinitrobenzoyl-(R,S)-leucine) solution (phosphate buffer, pH 6.58) and a chiral cinchona alkaloid

Estimation of total alkaloid in Chitrakadivati by UV-Spectrophotometer.

Science.gov (United States)

Ajanal, Manjunath; Gundkalle, Mahadev B; Nayak, Shradda U

2012-04-01

Herbal formulation standardization by adopting newer technique is need of the hour in the field of Ayurvedic pharmaceutical industry. As very few reports exist. These kind of studies would certainly widen the herbal research area. Chitrakadivati is one such popular herbal formulation used in Ayurveda. Many of its ingredients are known for presence of alkaloids. Presence of alkaloid was tested qualitatively by Dragondroff's method then subjected to quantitative estimation by UV-Spectrophotometer. This method is based on the reaction between alkaloid and bromocresol green (BCG). Study discloses that out of 16 ingredients, 9 contain alkaloid. Chitrakadivati has shown 0.16% of concentration of alkaloid and which is significantly higher than it's individual ingredients.

Preparation of Mesoporous SBA-16 Silica-Supported Biscinchona Alkaloid Ligand for the Asymmetric Dihydroxylation of Olefins

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Shaheen M. Sarkar

2014-01-01

Full Text Available Optically active cinchona alkaloid was anchored onto mesoporous SBA-16 silica and the as-prepared complex was used as a heterogeneous chiral ligand of osmium tetraoxide for the asymmetric dihydroxylation of olefins. The prepared catalytic system provided 90–93% yield of vicinal diol with 92–99% enantioselectivity. The ordered mesoporous SBA-16 silica was found to be a valuable support for the cinchona alkaloid liganded osmium catalyst system which is frequently used in chemical industries and research laboratories for olefin functionalization.

[Study on the separation process of pharmacological active total alkaloids from Chelidonium majus L. growing in Georgia].

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Bozhadze, A D; Vachnadze, V Iu; Dzhokhadze, M S; Berashvili, D T; Bakuridze, A Dzh

2013-04-01

In present article was studied the separation process of pharmacological active total alkaloids from Chelidonium majus L. growing in Georgia. Alkaloids were extracted from medicinal herbal material and separated by liquid extraction, diluents gas and a microfiltration through membrane equipment. The obtained A1, A2, A3 fractions were analyzed by GC/MS method; in all cases separation proceeds by the principle of extraction of the target alkaloids. It was concluded that the A1 is enriched with α and β cryptopins, and protopin, but homochelidonine and chelidonine are in low contents. As accompanying alkaloid is identified dihydrosanguinarine as an artifact; the A2 is enriched with the maximum contents of stylopine and protopin, but the poor contents of chelidonine and homochelidonine; the A3 is enriched with α and β cryptopins and maximum content of chelidonine. Extraction of alkaloids from Chelidonium majus L. proceeds selectively, but depending on a way of separation of the total alkaloids allows varying qualitative and quantitative consistence of the final product.

Enantioselective desymmetrization of prochiral cyclohexanones by organocatalytic intramolecular Michael additions to α,β-unsaturated esters.

Science.gov (United States)

Gammack Yamagata, Adam D; Datta, Swarup; Jackson, Kelvin E; Stegbauer, Linus; Paton, Robert S; Dixon, Darren J

2015-04-13

A new catalytic asymmetric desymmetrization reaction for the synthesis of enantioenriched derivatives of 2-azabicyclo[3.3.1]nonane, a key motif common to many alkaloids, has been developed. Employing a cyclohexanediamine-derived primary amine organocatalyst, a range of prochiral cyclohexanone derivatives possessing an α,β-unsaturated ester moiety linked to the 4-position afforded the bicyclic products, which possess three stereogenic centers, as single diastereoisomers in high enantioselectivity (83-99% ee) and in good yields (60-90%). Calculations revealed that stepwise C-C bond formation and proton transfer via a chair-shaped transition state dictate the exclusive endo selectivity and enabled the development of a highly enantioselective primary amine catalyst. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pharmacological Evaluation of Total Alkaloids from Nux Vomica: Effect of Reducing Strychnine Contents

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Jun Chen

2014-04-01

Full Text Available The aim of the study was to investigate the possibility of improving the therapeutic efficacy of the total alkaloid fraction (TAF extracted from processed nux vomica by reducing the strychnine contents. Most strychnine was removed from TAF to obtain the modified total alkaloid fraction (MTAF. The toxicity and pharmacokinetics of TAF and MTAF were further investigated and compared besides their antitumor, analgesic and anti-inflammatory activities. The results showed that the ratios of brucine to strychnine were 1:2.05 and 2.2:1 for TAF and MTAF, respectively, and the toxicity of TAF was about 3.17-fold higher than that of MTAF. Compared to brucine alone, the elimination of brucine was found to be inhibited by other alkaloids in TAF or MTAF except strychnine. Significantly increased pharmacological activities when administered by the oral route were obtained with MTAF in comparison to TAF and nux vomica powder (NVP. In summary, MTAF might replace NVP and TAF in the clinical application of Chinese medicine to obtain much higher efficacy.

A general enantioselective route to the chamigrene natural product family

KAUST Repository

White, David E.; Stewart, Ian C.; Seashore-Ludlow, Brinton A.; Grubbs, Robert H.; Stoltz, Brian M.

2010-01-01

Described in this report is an enantioselective route toward the chamigrene natural product family. The key disconnections in our synthetic approach include sequential enantioselective decarboxylative allylation and ring-closing olefin metathesis to form the all-carbon quaternary stereocenter and spirocyclic core present in all members of this class of compounds. The generality of this strategy is demonstrated by the first total syntheses of elatol and the proposed structure of laurencenone B, as well as the first enantioselective total syntheses of laurencenone C and α-chamigrene. A brief exploration of the substrate scope of the enantioselective decarboxylative allylation/ring-closing metathesis sequence with fully substituted vinyl chlorides is also presented.

A general enantioselective route to the chamigrene natural product family

KAUST Repository

White, David E.

2010-06-01

Described in this report is an enantioselective route toward the chamigrene natural product family. The key disconnections in our synthetic approach include sequential enantioselective decarboxylative allylation and ring-closing olefin metathesis to form the all-carbon quaternary stereocenter and spirocyclic core present in all members of this class of compounds. The generality of this strategy is demonstrated by the first total syntheses of elatol and the proposed structure of laurencenone B, as well as the first enantioselective total syntheses of laurencenone C and α-chamigrene. A brief exploration of the substrate scope of the enantioselective decarboxylative allylation/ring-closing metathesis sequence with fully substituted vinyl chlorides is also presented.

Anti-tumor potential of total alkaloid extract of Prosopis juliflora DC ...

African Journals Online (AJOL)

Jane

2011-08-15

Aug 15, 2011 ... Cancer is the second leading cause of death in the world. (Madhusudan and .... formula and from that the percentage of cytotoxicity and IC50 values ... complete media were treated as positive and negative controls, .... Cytotoxic effect of total alkaloid extract of P. juliflora leaves against cancer (black bars).

Anti-tumor potential of total alkaloid extract of Prosopis juliflora DC ...

African Journals Online (AJOL)

The total alkaloid extract from Prosopis juliflora DC. leaves was obtained using acid/base modified extraction method. The in vitro anti-tumor potential of the extract was evaluated using MTT (3-(4,5- dimethythiazol-2yl)2,5-diphenyl tetrazolium bromide) based cytotoxicity monitoring after 24, 48 and 72 h exposure of the ...

Rhodium-Catalyzed Asymmetric N-H Functionalization of Quinazolinones with Allenes and Allylic Carbonates: The First Enantioselective Formal Total Synthesis of (-)-Chaetominine.

Science.gov (United States)

Zhou, Yirong; Breit, Bernhard

2017-12-22

An unprecedented asymmetric N-H functionalization of quinazolinones with allenes and allylic carbonates was successfully achieved by rhodium catalysis with the assistance of chiral bidentate diphosphine ligands. The high efficiency and practicality of this method was demonstrated by a low catalyst loading of 1 mol % as well as excellent chemo-, regio-, and enantioselectivities with broad functional group compatibility. Furthermore, this newly developed strategy was applied as key step in the first enantioselective formal total synthesis of (-)-chaetominine. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthetic studies of the zoanthamine alkaloids: the total syntheses of norzoanthamine and zoanthamine.

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Yoshimura, Fumihiko; Sasaki, Minoru; Hattori, Izumi; Komatsu, Kei; Sakai, Mio; Tanino, Keiji; Miyashita, Masaaki

2009-07-06

The zoanthamine alkaloids, a type of heptacyclic marine alkaloid isolated from colonial zoanthids of the genus Zoanthus sp., have distinctive biological and pharmacological properties in addition to their unique chemical structures with stereochemical complexity. Namely, norzoanthamine (1) can suppress the loss of bone weight and strength in ovariectomized mice and has been expected as a promising candidate for a new type of antiosteoporotic drug, while zoanthamine (2) has exhibited potent inhibitory activity toward phorbol myristate-induced inflammation in addition to powerful analgesic effects. Recently, norzoanthamine derivatives were demonstrated to inhibit strongly the growth of P-388 murine leukemia cell lines, in addition to their potent antiplatelet activities on human platelet aggregation. Their distinctive biological properties, combined with novel chemical structures, make this family of alkaloids extremely attractive targets for chemical synthesis. However, the chemical synthesis of the zoanthamine alkaloids has been impeded owing to their densely functionalized complex stereostructures. In this paper, we report the first and highly efficient total syntheses of norzoanthamine (1) and zoanthamine (2) in full detail, which involve stereoselective synthesis of the requisite triene (18) for an intramolecular Diels-Alder reaction via the sequential three-component coupling reactions, the key intramolecular Diels-Alder reaction, and subsequent crucial bis-aminoacetalization as the key steps. Ultimately, we achieved the total synthesis of norzoanthamine (1) in 41 steps with an overall yield of 3.5 % (an average of 92 % yield each step) and that of zoanthamine (2) in 43 steps with an overall yield of 2.2 % (an average of 91 % yield each step) starting from (R)-5-methylcyclohexenone (3), respectively.

Antidepressant effects of total tertiary alkaloid fraction of Cissampelos sympodialis Eichler in rodents

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Sueli Mendonça-Netto

Full Text Available The purpose of the present study was to evaluate the effects of total tertiary alkaloid fraction (TTAF of Cissampelos sympodialis Eichler (Menispermaceae on two animal models of depression: a forced swim test and b reserpine test. Treatment of mice with TTAF (12.5 mg/kg reduced the total immobility time. It also reversed the reserpine-induced hypothermia, demonstrating an antidepressant effect in both models. Additionally, TTAF treatment did not modify the ambulation and rearing evaluated in open field test in order to investigate if the immobility time reduction found in the forced swimming test was caused by locomotive activity stimulation. Since warifteine is one of the main alkaloids present in the TTAF of C. sympodialis, and it has inhibitory activity of the phosphodiesterase enzyme, it may be responsible by the antidepressant effect found in the fraction studied.

Total Synthesis of the Spirocyclic Oxindole Alkaloids Corynoxine, Corynoxine B, Corynoxeine, and Rhynchophylline

NARCIS (Netherlands)

Wanner, M.J.; Ingemann, S.; van Maarseveen, J.H.; Hiemstra, H.

2013-01-01

Racemic total syntheses of four spirocyclic oxindole alkaloids are reported. The general starting material was an N-2-butenylated 2-hydroxytryptamine, which underwent a base-mediated Mannich spirocyclisation with a functionalised aldehyde to generate the C-ring. The second key step was a

Organocatalytic Enantioselective Pictet-Spengler Approach to Biologically Relevant 1-Benzyl-1,2,3,4-Tetrahydroisoquinoline Alkaloids

NARCIS (Netherlands)

Ruiz-Olalla, A.; Würdemann, M.A.; Wanner, M.J.; Ingemann, S.; van Maarseveen, J.H.; Hiemstra, H.

2015-01-01

A general procedure for the synthesis of 1-benzyl-1,2,3,4-tetrahydroisoquinolines was developed, based on organocatalytic, regio- and enantioselective Pictet-Spengler reactions (86-92% ee) of N-(o-nitrophenylsulfenyl)-2-arylethyl-amines with arylacetaldehydes. The presence of the

Lysergic acid amide as chemical marker for the total ergot alkaloids in rye flour - Determination by high-performance thin-layer chromatography-fluorescence detection.

Science.gov (United States)

Oellig, Claudia

2017-07-21

Ergot alkaloids are generally determined by high-performance liquid chromatography (HPLC) coupled to fluorescence detection (FLD) or mass selective detection, analyzing the individual compounds. However, fast and easy screening methods for the determination of the total ergot alkaloid content are more suitable, since for monitoring only the sum of the alkaloids is relevant. The herein presented screening uses lysergic acid amide (LSA) as chemical marker, formed from ergopeptine alkaloids, and ergometrine for the determination of the total ergot alkaloids in rye with high-performance thin-layer chromatography-fluorescence detection (HPTLC-FLD). An ammonium acetate buffered extraction step was followed by liquid-liquid partition for clean-up before the ergopeptine alkaloids were selectively transformed to LSA and analyzed by HPTLC-FLD on silica gel with isopropyl acetate/methanol/water/25% ammonium hydroxide solution (80:10:3.8:1.1, v/v/v/v) as the mobile phase. The enhanced native fluorescence of LSA and unaffected ergometrine was used for quantitation without any interfering matrix. Limits of detection and quantitation were 8 and 26μg LSA/kg rye, which enables the determination of the total ergot alkaloids far below the applied quality criterion limit for rye. Close to 100% recoveries for different rye flours at relevant spiking levels were obtained. Thus, reliable results were guaranteed, and the fast and efficient screening for the total ergot alkaloids in rye offers a rapid alternative to the HPLC analysis of the individual compounds. Copyright © 2017 Elsevier B.V. All rights reserved.

Quantitative analysis of total retronecine esters-type pyrrolizidine alkaloids in plant by high performance liquid chromatography

International Nuclear Information System (INIS)

Zhang Fang; Wang Changhong; Xiong Aizhen; Wang Wan; Yang Li; Branford-White, Christopher J.; Wang Zhengtao; Bligh, S.W. Annie

2007-01-01

Pyrrolizidine alkaloids (PAs) are alkaloids which typically contain a necine (7-hydroxy-1-hydroxymethyl-6,7-dihydro-5H-pyrrolizidine) base unit, and they can be found in one third of the higher plants around the world. They are hepatotoxic, mutagenic and carcinogenic and pose a threat to human health and safety. A specific, quick and sensitive method is therefore needed to detect and quantify the PAs sometimes in trace amount in herbs, tea or food products. Based on high performance liquid chromatography with prior derivatization of the alkaloids using o-chloranil and Ehrlich's reagent, we report an improved method for quantitative analysis of the total amount of retronecine esters-type pyrrolizidine alkaloids (RET-PAs) in a plant extract. The total quantitation of RET-PAs is achieved because of a common colored retronecine marker, a 7-ethoxy-1-ethoxylmethyl retronecine derivative, is produced with all the different RET-PAs during the derivatization reaction. The chemical identity of the common retronecine marker was characterized on-line by positive mode electrospray ionization mass spectrometry and nuclear magnetic resonance spectroscopy. The limit of detection using the improved method is 0.26 nmol mL -1 and the limit of quantitation is 0.79 nmol mL -1 . The advantages of this method are much enhanced sensitivity in detection and quantitation, and, no restriction on the choice of RET-PA as a calibration standard. Application of the developed method to the quantitation of total RET esters-type PAs in Senecio scandens from different regions of China is also reported

Quantitative analysis of total retronecine esters-type pyrrolizidine alkaloids in plant by high performance liquid chromatography

Energy Technology Data Exchange (ETDEWEB)

Zhang Fang; Wang Changhong; Xiong Aizhen; Wang Wan; Yang Li [Key Laboratory of Standardization of Chinese Medicines of Ministry of Education, Shanghai University of Traditional Chinese Medicine, 1200 Cai Lun Road, Zhangjiang Hi-Tech Park, Shanghai 201203 (China); Branford-White, Christopher J. [Institute for Health Research and Policy, London Metropolitan University, 166-220 Holloway Road, London N7 8DB (United Kingdom); Wang Zhengtao [Key Laboratory of Standardization of Chinese Medicines of Ministry of Education, Shanghai University of Traditional Chinese Medicine, 1200 Cai Lun Road, Zhangjiang Hi-Tech Park, Shanghai 201203 (China); School of Chinese Pharmacy, China Pharmaceutical University, Nanjing 210038 (China)], E-mail: wangzt@shutcm.edu.cn; Bligh, S.W. Annie [Institute for Health Research and Policy, London Metropolitan University, 166-220 Holloway Road, London N7 8DB (United Kingdom)], E-mail: a.bligh@londonmet.ac.uk

2007-12-12

Pyrrolizidine alkaloids (PAs) are alkaloids which typically contain a necine (7-hydroxy-1-hydroxymethyl-6,7-dihydro-5H-pyrrolizidine) base unit, and they can be found in one third of the higher plants around the world. They are hepatotoxic, mutagenic and carcinogenic and pose a threat to human health and safety. A specific, quick and sensitive method is therefore needed to detect and quantify the PAs sometimes in trace amount in herbs, tea or food products. Based on high performance liquid chromatography with prior derivatization of the alkaloids using o-chloranil and Ehrlich's reagent, we report an improved method for quantitative analysis of the total amount of retronecine esters-type pyrrolizidine alkaloids (RET-PAs) in a plant extract. The total quantitation of RET-PAs is achieved because of a common colored retronecine marker, a 7-ethoxy-1-ethoxylmethyl retronecine derivative, is produced with all the different RET-PAs during the derivatization reaction. The chemical identity of the common retronecine marker was characterized on-line by positive mode electrospray ionization mass spectrometry and nuclear magnetic resonance spectroscopy. The limit of detection using the improved method is 0.26 nmol mL{sup -1} and the limit of quantitation is 0.79 nmol mL{sup -1}. The advantages of this method are much enhanced sensitivity in detection and quantitation, and, no restriction on the choice of RET-PA as a calibration standard. Application of the developed method to the quantitation of total RET esters-type PAs in Senecio scandens from different regions of China is also reported.

Isoindolinones as Michael Donors under Phase Transfer Catalysis: Enantioselective Synthesis of Phthalimidines Containing a Tetrasubstituted Carbon Stereocenter

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Francesco Scorzelli

2015-05-01

Full Text Available Readily available chiral ammonium salts derived from cinchona alkaloids have proven to be effective phase transfer catalysts in the asymmetric Michael reaction of 3-substituted isoindolinones. This protocol provides a convenient method for the construction of valuable asymmetric 3,3-disubstituted isoindolinones in high yields and  moderate to good enantioselectivity. Diastereoselectivity was also investigated in the construction of contiguous tertiary and quaternary stereocenters. The use of acrolein as Michael acceptor led to an interesting tricyclic derivative, a pyrroloisoindolinone analogue, via a tandem conjugated addition/cyclization reaction.

A Mixed-Ligand Chiral Rhodium(II) Catalyst Enables the Enantioselective Total Synthesis of Piperarborenine B.

Science.gov (United States)

Panish, Robert A; Chintala, Srinivasa R; Fox, Joseph M

2016-04-11

A novel, mixed-ligand chiral rhodium(II) catalyst, Rh2(S-NTTL)3(dCPA), has enabled the first enantioselective total synthesis of the natural product piperarborenine B. A crystal structure of Rh2(S-NTTL)3(dCPA) reveals a "chiral crown" conformation with a bulky dicyclohexylphenyl acetate ligand and three N-naphthalimido groups oriented on the same face of the catalyst. The natural product was prepared on large scale using rhodium-catalyzed bicyclobutanation/ copper-catalyzed homoconjugate addition chemistry in the key step. The route proceeds in ten steps with an 8% overall yield and 92% ee. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bicyclic Guanidine Catalyzed Asymmetric Tandem Isomerization Intramolecular-Diels-Alder Reaction: The First Catalytic Enantioselective Total Synthesis of (+)-alpha-Yohimbine.

Science.gov (United States)

Feng, Wei; Jiang, Danfeng; Kee, Choon-Wee; Liu, Hongjun; Tan, Choon-Hong

2016-02-04

Hydroisoquinoline derivatives were prepared in moderate to good enantioselectivities via a bicyclic guanidine-catalyzed tandem isomerization intramolecular-Diels-Alder (IMDA) reaction of alkynes. With this synthetic method, the first enantioselective synthesis of (+)-alpha-yohimbine was completed in 9 steps from the IMDA products. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A General Cp*CoIII -Catalyzed Intramolecular C-H Activation Approach for the Efficient Total Syntheses of Aromathecin, Protoberberine, and Tylophora Alkaloids.

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Lerchen, Andreas; Knecht, Tobias; Koy, Maximilian; Daniliuc, Constantin G; Glorius, Frank

2017-09-07

Herein, we report a Cp*Co III -catalyzed C-H activation approach as the key step to create highly valuable isoquinolones and pyridones as building blocks that can readily be applied in the total syntheses of a variety of aromathecin, protoberberine, and tylophora alkaloids. This particular C-H activation/annulation reaction was achieved with several terminal as well as internal alkyne coupling partners delivering a broad scope with excellent functional group tolerance. The synthetic applicability of this protocol reported herein was demonstrated in the total syntheses of two Topo-I-Inhibitors and two 8-oxyprotoberberine cores that can be further elaborated into the tetrahydroprotoberberine and the protoberberine alkaloid core. Moreover these building blocks were also transformed to six different tylophora alkaloids in expedient fashion. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pyrrolizidine alkaloids.

Science.gov (United States)

Robertson, Jeremy; Stevens, Kiri

2014-12-01

This review covers pyrrolizidine alkaloids isolated from natural sources. Topics include: aspects of structure, isolation, and biological/pharmacological studies; total syntheses of necic acids, necine bases and closely-related non-natural analogues.

Visual identification of alkaloids in some medicinal plants: common alkaloid reagents versus bromocresol green

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Shamsa F, Esfahani HR, Gamooshi RA

2008-07-01

Full Text Available "n Normal 0 false false false MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} Background: Alkaloids are a group of nitrogenous compounds with potential effects on the physiological behavior of human and animals. Some of these compounds are considered important drugs in modern medicine, such as atropine and morphine. Plants are considered the most important source of alkaloids. Therefore, investigating the presence of alkaloids in different plants is very important. Usually, alkaloids in plants are identified by methods such as those of Dragendorf, Wagner and Meyer, among others, which require milligrams of alkaloids for identification. In the present study, a fast and sensitive procedure for detecting of alkaloids in plants is presented.   "n"nMethods: Twelve dried plants samples were investigated for the presence alkaloids. After extracting the total alkaloid into methanol using a Soxhlet extractor, a few milligrams of the extract was transferred to a separatory funnel, buffered to pH 4.7, the bromocresol green (BCG solution (10-4 M was added, mixed and extracted with CHCl3 until a yellow color was observed in the CHCl3 layer, indicating the presence of the alkaloid. The crude extracts were also investigated by the standard methods of Dragendorf, Wagner and Meyer for the presence of alkaloids.   "n"nResults: Investigation of the 12 plant samples for the presence of alkaloids by the standard reagents of Dragendorf, Wagner, and Meyer showed that only Camelia sinensis (flowers, Echium amoenum Fisch & Mey (flowers, and Stachys (aerial parts are devoid

Enantioselectivity in environmental risk assessment of modern chiral pesticides

International Nuclear Information System (INIS)

Ye Jing; Zhao Meirong; Liu Jing; Liu Weiping

2010-01-01

Chiral pesticides comprise a new and important class of environmental pollutants nowadays. With the development of industry, more and more chiral pesticides will be introduced into the market. But their enantioselective ecotoxicology is not clear. Currently used synthetic pyrethroids, organophosphates, acylanilides, phenoxypropanoic acids and imidazolinones often behave enantioselectively in agriculture use and they always pose unpredictable enantioselective ecological risks on non-target organisms or human. It is necessary to explore the enantioselective toxicology and ecological fate of these chiral pesticides in environmental risk assessment. The enantioselective toxicology and the fate of these currently widely used pesticides have been discussed in this review article. - Chiral pesticides could pose unpredictable enantioselective toxicity on non-target organisms.

Alkaloids from single skins of the Argentinian toad Melanophryniscus rubriventris (ANURA, BUFONIDAE): An unexpected variability in alkaloid profiles and a profusion of new structures

OpenAIRE

Garraffo, H Martin; Andriamaharavo, Nirina R; Vaira, Marcos; Quiroga, Mar?a F; Heit, Cecilia; Spande, Thomas F

2012-01-01

GC-MS analysis of single-skins of ten Melanophryniscus rubriventris toads (five collections of two toads each) captured during their breeding season in NW Argentina has revealed a total of 127 alkaloids of which 56 had not been previously detected in any frog or toad. Included among these new alkaloids are 23 new diastereomers of previously reported alkaloids. What is particularly distinguishing about the alkaloid profiles of these ten collections is the occurrence of many of the alkaloids, w...

Total Alkaloids of Sophora alopecuroides Inhibit Growth and Induce Apoptosis in Human Cervical Tumor HeLa Cells In vitro.

Science.gov (United States)

Li, Jian-Guang; Yang, Xiao-Yi; Huang, Wei

2016-05-01

Uygur females of Xinjiang have the higher incidence of cervical tumor in the country. Alkaloids are the major active ingredients in Sophora alopecuroides, and its antitumor effect was recognized by the medical profession. Xinjiang is the main site of S. alopecuroides production in China so these plants are abundant in the region. Studies on the antitumor properties of total alkaloids of S. alopecuroides (TASA) can take full use of the traditional folk medicine in antitumor unique utility. To explore the effects of TASA on proliferation and apoptosis of human cervical tumor HeLa cells in vitro. TASA was extracted, purified, and each monomer component was analyzed by high-performance liquid chromatography. The effect of TASA at different concentrations on the survival of HeLa cells was determined after 24 h using the Cell Counting Kit-8. In addition, cells were photographed using an inverted microscope to document morphological changes. The effect of TASA on apoptotic rate of HeLa cells was assessed by flow cytometry. Monomers of TASA were found to be sophoridine, matrine, and sophocarpine. On treatment with 8.75 mg/ml of TASA, more than 50% of HeLa cells died, and cell death rate increased further with longer incubation. The apoptotic rates of HeLa cells in the experimental groups were 16.0% and 33.3% at concentrations of 6.25 mg/ml and 12.50 mg/ml, respectively. TASA can induce apoptosis in cervical tumor HeLa cells, and it has obvious inhibitory effects on cell growth. Total alkaloids of Sophora alopecuroides (TASA) exhibits anti-human cervical tumor propertiesMonomer component of TASA was analyzed by high-performance liquid chromatography, and its main effect component are sophoridine, matrine, and sophocarpineTASA inhibits growth and induces apoptosis in HeLa cells. Abbreviations used: TASA: Total alkaloids of S. alopecuroides, CCK-8: Cell Counting Kit-8, FBS: Fetal bovine serum, PBS: Phosphate buffered saline, DMEM: Dulbecco's modified Eagle medium.

Enantioselective pharmacokinetics of sibutramine in rat.

Science.gov (United States)

Noh, Keumhan; Bae, Kyoungjin; Min, Bokyoung; Kim, Eunyoung; Kwon, Kwang-il; Jeong, Taecheon; Kang, Wonku

2010-02-01

Racemic sibutramine is widely used to treat obesity owing to its inhibition of serotonin and noradrenaline reuptake in synapses. Although the enantioselective effects of sibutramine and its two active desmethyl-metabolites, monodesmethylsibutramine (MDS) and didesmethylsibutramine (DDS), on anorexia and energy expenditure have been elucidated, the enantioselective pharmacokinetics of sibutramine are still unclear. Therefore, we aimed to characterize the enantioselective pharmacokinetics of sibutramine and its metabolites in plasma and urine following an intravenous and a single oral administration of sibutramine in rats. The absolute bioavailability of sibutramine was only about 7%. The pharmacologically less effective S-isomer of DDS was predominant in the plasma: the C ( max ) and the AUC ( inf ) were 28 and 30 times higher than those of the R-isomer, respectively (psibutramine metabolites MDS and DDS were present at lower concentrations, owing to their rapid biotransformation to hydroxylated and/or carbamoylglucuronized forms and their faster excretion in the urine. The present study is the first to elucidate the enantioselective pharmacokinetics of sibutramine in rats.

Direct enantioselective conjugate addition of carboxylic acids with chiral lithium amides as traceless auxiliaries.

Science.gov (United States)

Lu, Ping; Jackson, Jeffrey J; Eickhoff, John A; Zakarian, Armen

2015-01-21

Michael addition is a premier synthetic method for carbon-carbon and carbon-heteroatom bond formation. Using chiral dilithium amides as traceless auxiliaries, we report the direct enantioselective Michael addition of carboxylic acids. A free carboxyl group in the product provides versatility for further functionalization, and the chiral reagent can be readily recovered by extraction with aqueous acid. The method has been applied in the enantioselective total synthesis of the purported structure of pulveraven B.

Steroidal glyco alkaloids and molluscicidal activity of Solanum asperum Rich. fruits

Energy Technology Data Exchange (ETDEWEB)

Silva, Tania M.S. [Instituto Multidisciplinar em Saude, Vitoria da Conquista, BA (Brazil). Campus Avancado Anisio Teixeira]. E-mail: sarmento@pesquisador.cnpq.br; Camara, Celso A. [Universidade Federal Rural de Pernambuco, Recife, PE (Brazil). Dept. de Quimica; Freire, Kristerson R.L.; Silva, Thiago G. da; Agra, Maria de F.; Bhattacharyya, Jnanabrata [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil). Lab. de Tecnologia Farmaceutica

2008-07-01

Bioassay-guided fractionation of the alkaloidal extract of the green fruits of Solanum asperum afforded a new compound, solanandaine along with solasonine and solamargine. The total crude alkaloids as well as the isolated pure alkaloids exhibited significant molluscicidal activity. (author)

Direct Enantioselective Conjugate Addition of Carboxylic Acids with Chiral Lithium Amides as Traceless Auxiliaries

Science.gov (United States)

2016-01-01

Michael addition is a premier synthetic method for carbon–carbon and carbon–heteroatom bond formation. Using chiral dilithium amides as traceless auxiliaries, we report the direct enantioselective Michael addition of carboxylic acids. A free carboxyl group in the product provides versatility for further functionalization, and the chiral reagent can be readily recovered by extraction with aqueous acid. The method has been applied in the enantioselective total synthesis of the purported structure of pulveraven B. PMID:25562717

Tin-free enantioselective radical reactions using silanes.

Science.gov (United States)

Sibi, Mukund P; Yang, Yong-Hua; Lee, Sunggi

2008-12-04

Readily available hexyl silane is an excellent choice as a H-atom donor and a chain carrier in Lewis acid mediated enantioselective radical reactions. Conjugate radical additions to alpha,beta-unsaturated imides at room temperature proceed in good yields and excellent enantioselectivities.

Alkaloids in Solanum torvum Sw (Solanaceae): (With 2 Tables & 1 Figure)

OpenAIRE

Pérez-Amador, MC; Muñoz Ocotero, V; García Castañeda, JM; González Esquinca, AR

2007-01-01

A comparison was made between plants of Solanum torvum Sw that grow in Chiapas, Mexico, and plants of the same species originating from India. This was effected to establish either similarities or differences between these plants in total alkaloid contents and presence of solasodine, an important alkaloid for the partial synthesis of steroids. The total alkaloid content (0.12%) of the plants coming from Chiapas and India was the same. However, solasodine was found only in the plants of Chiapa...

New Perspectives in the Chemistry of Marine Pyridoacridine Alkaloids

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Alois Plodek

2016-01-01

Full Text Available Secondary metabolites from marine organisms are a rich source of novel leads for drug development. Among these natural products, polycyclic aromatic alkaloids of the pyridoacridine type have attracted the highest attention as lead compounds for the development of novel anti-cancer and anti-infective drugs. Numerous sophisticated total syntheses of pyridoacridine alkaloids have been worked out, and many of them have also been extended to the synthesis of libraries of analogues of the alkaloids. This review summarizes the progress in the chemistry of pyridoacridine alkaloids that was made in the last one-and-a-half decades.

[Protective effect of Uncaria rhynchophylla total alkaloids pretreatment on hippocampal neurons after acute hypoxia].

Science.gov (United States)

Liu, Wei; Zhang, Zhao-qin; Zhao, Xiao-min; Gao, Yun-sheng

2006-05-01

To investigate the effect of Uncaria rhynchophylla total alkaloids (RTA) pretreatment on the voltage-gated sodium currents of the rat hippocampal neurons after acute hypoxia. Primary cultured hippocampal neurons were divided into RTA pre-treated and non-pretreated groups. Patch clamp whole-cell recording was used to compare the voltage-gated sodium current amplitude and threshold with those before hypoxia. After acute hypoxia, sodium current amplitude was significantly decreased and its threshold was upside. RTA pretreatment could inhibit the reduction of sodium current amplitude. RTA pretreatment alleviates the acute hypoxia-induced change of sodium currents, which may be one of the mechanisms for protective effect of RTA on cells.

Renoprotective Effects of Total Glucosides from Paeony against Nephrotoxicity Induced by Total Alkaloids from Semen Strychni

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Mingming Lv

2017-01-01

Full Text Available Semen Strychni have been shown to have therapeutic effect in improving blood circulation, relieving rheumatic pain, and treating cancer. However, Semen Strychni could cause severe nephrotoxicity. The present study was designed to evaluate whether treatment with total glucosides from paeony (TGP has renoprotective effect against nephrotoxicity induced by total alkaloids from Semen Strychni (TAS. The levels of blood urea nitrogen (BUN and creatinine (Cr were determined and histopathological changes were also examined to evaluate renal injury. Moreover, a HPLC-MS method was developed and validated to investigate the comparative toxicokinetics of strychnine and brucine in rats plasma after oral administration of TAS and pretreatment with TGP. Results demonstrated that the levels of BUN and Cr were significantly increased (p<0.05 in TAS group, together with tubule epithelium cloudy swelling, degeneration, and glomerular atrophy in rats’ kidneys. The TAS-induced kidney damage was alleviated after pretreatment with TGP. Besides, Tmax of strychnine and brucine were increased and T1/2 of strychnine and brucine were decreased after pretreatment with TGP. The toxicokinetics study showed that pretreatment with TGP could attenuate the absorption of strychnine and brucine, as well as accelerate their elimination. These results suggest that TGP possesses renoprotective effects.

New Perspectives in the Chemistry of Marine Pyridoacridine Alkaloids ?

OpenAIRE

Plodek, Alois; Bracher, Franz

2016-01-01

Secondary metabolites from marine organisms are a rich source of novel leads for drug development. Among these natural products, polycyclic aromatic alkaloids of the pyridoacridine type have attracted the highest attention as lead compounds for the development of novel anti-cancer and anti-infective drugs. Numerous sophisticated total syntheses of pyridoacridine alkaloids have been worked out, and many of them have also been extended to the synthesis of libraries of analogues of the alkaloids...

Total Synthesis of Zoanthamine Alkaloids, Part 2. Construction of the C1-C5, C6-C10 and C11-C24 Fragments of Zoanthamine

DEFF Research Database (Denmark)

Tanner, David Ackland; Tedenborg, Lars; Somfai, Peter

1997-01-01

This paper describes the construction of three key intermediates for a projected total synthesis of the marine alkaloid zoanthamine. These building blocks, corresponding to the C1-C5, C6-C10 and C11-C24 fragments of the target molecule, are synthesised efficiently form (R)-hydroxymethyl-butyrolac......This paper describes the construction of three key intermediates for a projected total synthesis of the marine alkaloid zoanthamine. These building blocks, corresponding to the C1-C5, C6-C10 and C11-C24 fragments of the target molecule, are synthesised efficiently form (R...

Low-Mode Conformational Search Method with Semiempirical Quantum Mechanical Calculations: Application to Enantioselective Organocatalysis.

Science.gov (United States)

Kamachi, Takashi; Yoshizawa, Kazunari

2016-02-22

A conformational search program for finding low-energy conformations of large noncovalent complexes has been developed. A quantitatively reliable semiempirical quantum mechanical PM6-DH+ method, which is able to accurately describe noncovalent interactions at a low computational cost, was employed in contrast to conventional conformational search programs in which molecular mechanical methods are usually adopted. Our approach is based on the low-mode method whereby an initial structure is perturbed along one of its low-mode eigenvectors to generate new conformations. This method was applied to determine the most stable conformation of transition state for enantioselective alkylation by the Maruoka and cinchona alkaloid catalysts and Hantzsch ester hydrogenation of imines by chiral phosphoric acid. Besides successfully reproducing the previously reported most stable DFT conformations, the conformational search with the semiempirical quantum mechanical calculations newly discovered a more stable conformation at a low computational cost.

Alkaloids from single skins of the Argentinian toad Melanophryniscus rubriventris (ANURA, BUFONIDAE): An unexpected variability in alkaloid profiles and a profusion of new structures.

Science.gov (United States)

Garraffo, H Martin; Andriamaharavo, Nirina R; Vaira, Marcos; Quiroga, María F; Heit, Cecilia; Spande, Thomas F

2012-12-01

GC-MS analysis of single-skins of ten Melanophryniscus rubriventris toads (five collections of two toads each) captured during their breeding season in NW Argentina has revealed a total of 127 alkaloids of which 56 had not been previously detected in any frog or toad. Included among these new alkaloids are 23 new diastereomers of previously reported alkaloids. What is particularly distinguishing about the alkaloid profiles of these ten collections is the occurrence of many of the alkaloids, whether known or new to us, in only one of the ten skins sampled, despite two skins being obtained from each breeding site of the five populations. Many of the alkaloids are of classes known to have structures with branched-chains (e.g. pumiliotoxins and tricyclic structures) that are considered to derive from dietary mites. A large number of previously reported and new alkaloids are also of unclassified structures. Only a very few 3,5-disubstituted-indolizidine or -pyrrolizidine alkaloids are observed that have a straight-chain carbon skeleton and are likely derived from ant prey. The possible relationship of these collections made during the toad's brief breeding episodes to sequestration of dietary arthropods and individual alkaloid profiles is discussed.

Potential of solid state fermentation for production of ergot alkaloids

OpenAIRE

Trejo Hernandez, M.R.; Raimbault, Maurice; Roussos, Sevastianos; Lonsane, B.K.

1992-01-01

Production of total ergot alkaloids by #Claviceps fusiformis$ in solid state fermentation was 3.9 times higher compared to that in submerged fermentation. Production was equal in the case of #Claviceps purpurea$ but the spectra of alkaloids were advantageous with the use of solid state fermentation. The data establish potential of solid state fermentation which was not explored earlier for production of ergot alkaloids. (Résumé d'auteur)

Molecular docking study of Papaver alkaloids to some alkaloid receptors

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A. Nofallah

2017-11-01

Full Text Available Background and objectives: More than 40 different alkaloids have been obtained from opium the most important of which are morphine, codeine, papaverine, noscapine and tabaine. Opioid alkaloids produce analgesia by affecting areas of the brain that have peptides with pharmacological pseudo-opioid properties. These alkaloids show important effects on some intracellular peptides like mu, delta, and kappa receptors. Therefore, studying the effects of these alkaloids on different receptors is essential. Methods: Molecular docking is a well-known method in exploring the protein-ligand interactions. In this research, five important alkaloids were docked to crystal structure of human mu opioid receptor (4DKL, human delta opioid receptor (4EJ4 and human kappa opioid receptor (4DJH which were retrieved from protein databank. The 3D-structures of alkaloids were drawn by chembiooffice2010 and minimized with hyperchem package and submitted to molecular docking utilizing autodock-vina. Flexibility of the proteins was considered. The docking studies were performed to compare the affinity of these five alkaloids to the mentioned receptors. Results: We computationally docked each alkaloid compound onto each receptor structure and estimated their binding affinity based on dock scores. Dock score is a criteria including binding energy which utilized here for prediction and comparison of the binding affinities. Binding interactions of the docked alkaloids in receptor pockets were also visually inspected and compared. Conclusion: In this approach, using docking study as a computational method provided a valuable insight of opioid receptor pocket structures which would be essential to design more efficient drugs in pain managements and addiction treatments.

Chiral amides via copper-catalysed enantioselective conjugate addition

NARCIS (Netherlands)

Schoonen, Anne K.; Fernández-Ibáñez, M. Ángeles; Fañanás-Mastral, Martín; Teichert, Johannes F.; Feringa, Bernard

2014-01-01

A highly enantioselective one pot procedure for the synthesis of beta-substituted amides was developed starting from the corresponding alpha,beta-unsaturated esters. This new methodology is based on the copper-catalysed enantioselective conjugate addition of Grignard reagents to

Alkaloids from Delphinium pentagynum.

Science.gov (United States)

Díaz, Jesús G; Ruiz, Juan García; Herz, Werner

2004-07-01

Aerial parts of a collection of Delphinium pentagynum Lam. from Niebla, Southern Spain, furnished one diterpene alkaloid, 2-dehydrodeacetylheterophylloidine, two norditerpene alkaloids, 14-demethyl-14-isobutyrylanhweidelphinine and 14-demethyl-14-acetylanhweidelphinine, the known alkaloids 14-deacetylnudicauline, methyllycaconitine, 14-deacetyl-14-isobutyrylnudicauline, 14-acetylbrowniine, browniine, delcosine, lycoctonine, 18-methoxygadesine, neoline, karakoline and the aporphine alkaloid magnoflorine. Structures of the alkaloids were established by MS, 1D and 2-D NMR techniques.

Protective effects of total alkaloids from Dendrobium crepidatum against LPS-induced acute lung injury in mice and its chemical components.

Science.gov (United States)

Hu, Yang; Ren, Jie; Wang, Lei; Zhao, Xin; Zhang, Mian; Shimizu, Kuniyoshi; Zhang, Chaofeng

2018-05-01

Dendrobium crepidatum was one of the sources of Herba Dendrobii, a famous and precious traditional Chinese medicine. Indolizine-type alkaloids are the main characteristic ingredients of D. crepidatum, which possesses a variety of changeable skeletons. In the present study, we found that the total alkaloids of D. crepidatum (TAD) can inhibit the production of nitric oxide (NO) in lipopolysaccharide (LPS)-activated macrophages and showed protective effects against LPS-induced acute lung injury (ALI) in mice through downregulating the TLR4-mediated MyD88/MAPK signaling pathway. Further phytochemical study showed that six previously undescribed indolizine-type compounds, including a racemic mixture (dendrocrepidine A-E) were isolated from TAD. Meanwhile, dendrocrepidine F was separated into a pair of enantiomers by a chiral chromatography, and their absolute configurations were assigned by single-crystal X-ray diffraction analysis. The isomer (-)-dendrocrepidine F showed higher anti-inflammatory effects by inhibiting NO production in LPS-treated macrophages with an IC 50 value of 13.3 μM. Taken together, indolizine-type alkaloids are the active components of D. crepidatum through downregulating the TLR4-mediated pathway, indicating some kind of therapy of TAD for ALI treatment. Copyright © 2018 Elsevier Ltd. All rights reserved.

Studies on the Alkaloids of the Calycanthaceae and Their Syntheses

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Jin-Biao Xu

2015-04-01

Full Text Available Plants of the Calycanthaceae family, which possesses four genera and about 15 species, are mainly distributed in China, North America and Australia. Chemical studies on the Calycanthaceae have led to the discovery of about 14 alkaloids of different skeletons, including dimeric piperidinoquinoline, dimeric pyrrolidinoindoline and/or trimeric pyrrolidinoindolines, which exhibit significant anti-convulsant, anti-fungal, anti-viral analgesic, anti-tumor, and anti-melanogenesis activities. As some of complex tryptamine-derived alkaloids exhibit promising biological activities, the syntheses of these alkaloids have also been a topic of interest in synthetic chemistry during the last decades. This review will focus on the structures and total syntheses of these alkaloids.

Antinociceptive and Anti-Inflammatory Effects of Total Alkaloid Extract from Fumaria capreolata

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Noureddine Bribi

2015-01-01

Full Text Available Fumaria capreolata is used in traditional medicine in North Africa for its gastrointestinal and anti-inflammatory activities. The present study investigates the effects of total alkaloids extracted from the aerial parts of Fumaria capreolata (AFC on LPS-induced production of proinflammatory mediators (IL-6, IL-1β, iNOS, TNF-α, COX-2, and MIP-2 in RAW264.7 cells. AFC significantly reduced the inflammatory response inhibiting the production of nitric oxide (NO and IL-6 in a dose-dependent manner, without affecting the viability of cells, and downregulated mRNA expression of proinflammatory key players: IL-6, IL-1β, iNOS, TNF-α, and COX-2. AFC antinociceptive and anti-inflammatory properties were also evaluated on the acetic acid- and formalin-induced pain models in mice. AFC oral administration significantly inhibited acetic acid-induced writhes and reduced formalin-induced paw licking time. Therefore, AFC may be a potential candidate for the treatment of inflammatory diseases, such as colitis and arthritis.

Cytotoxic 1,3-Thiazole and 1,2,4-Thiadiazole Alkaloids from Penicillium oxalicum: Structural Elucidation and Total Synthesis

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Zheng Yang

2016-02-01

Full Text Available Two new thiazole and thiadiazole alkaloids, penicilliumthiamine A and B (2 and 3, were isolated from the culture broth of Penicillium oxalicum, a fungus found in Acrida cinerea. Their structures were elucidated mainly by spectroscopic analysis, total synthesis and X-ray crystallographic analysis. Biological evaluations indicated that compound 1, 3a and 3 exhibit potent cytotoxicity against different cancer cell lines through inhibiting the phosphorylation of AKT/PKB (Ser 473, one of important cancer drugs target.

Effects of Supplementation of Alkaloid and Non Alkaloid from Sauropus androgynus Leaves on Egg Production and Lipid Profil in Layer Chicken

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U Santoso

2010-09-01

Full Text Available The present study was conducted to evaluate effects of supplementation of alkaloid or non alkaloid from Sauropus androgynus leaves on productive performance and the contents of lipid fractions in layer chickens. Forty two layer chickens aged 30 weeks were distributed to seven treatment groups. Each treatment group contained six layer chickens maintained in an individual cage, respectively. The present experiment used completely randomized experimental design. The seven treatment groups were as follows: 1 Control, layer chickens were fed diet without supplementation of alkaloid or non alkaloid extracted from Sauropus androgynus (P0; 2 Layer chickens were fed diet contained 30 mg non alkaloid/kg diet (P1; 3 Layer chickens were fed diet contained 60 mg non alkaloid/kg diet (P2; 4 Layer chickens were fed diet contained 90 mg non alkaloid/kg diet (P3; 5 Layer chickens were fed diet contained 30 mg alkaloid/kg diet (P4; 6 Layer chickens were fed diet contained 60 mg alkaloid/kg diet (P5; 7 Layer chickens were fed diet contained 90 mg alkaloid/kg diet (P6. Layer chickens were fed experimental diet with 2,750 kcal/kg Metabolizable Energy (ME and 16.0% protein. Diet and drinking water were fed ad libitum. Experimental results showed that supplementation of alkaloid or non alkaloid from Sauropus androgynus leaves significantly affected productive performance in layer chickens. It appear that non alkaloid supplementation had no advantage in improving productive performance, whereas supplementation of 30 mg alkaloid/kg diet might have advantages in improving productive performance as indicated by better egg production and lower feed conversion ratio. Treatment had no effect on glucose and triglyceride concentration in serum, but it affected total cholesterol, HDL-cholesterol, LDL+VLDL-cholesterol and atherogenic index in serum. Cholesterol concentration in serum was significantly increased in P4 and P6, whereas HDL-cholesterol concentration was

Total Synthesis of Natural Products Using Hypervalent Iodine Reagents

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Gaetan eMaertens

2015-01-01

Full Text Available We present a review of natural product syntheses accomplished in our laboratory during the last five years. Each synthetic route features a phenol dearomatization promoted by an environmentally benign hypervalent iodine reagent. The dearomatizations demonstrate the aromatic ring umpolung concept, and involve stereoselective remodeling of the inert unsaturations of a phenol into a highly functionalized key intermediate that may contain a quaternary carbon center and a prochiral dienone system. Several new oxidative strategies were employed, including transpositions (1,3-alkyl shift and Prins-pinacol, a polycyclization, an ipso rearrangement, and direct nucleophilic additions at the phenol para position. Several alkaloids, heterocyclic compounds, and a polycyclic core have been achieved, including sceletenone (a serotonin reuptake inhibitor, acetylaspidoalbidine (an antitumor agent, fortucine (antiviral and antitumor, erysotramidine (curare-like effect, platensimycin (an antibiotic, and the main core of a kaurane diterpene (immunosuppressive agent and stimulator of apoptosis. These concise and in some cases enantioselective syntheses effectively demonstrate the importance of hypervalent iodine reagents in the total synthesis of bioactive natural products.

[Effect of different parts, harvesting time and processing technologies on alkaloids content of Coptis chinensis adventitious root].

Science.gov (United States)

Pang, Jie; Wang, De-Zhen; Zou, Zong-Yao; Wang, Yan-Zhi; Gao, Qian; Li, Xue-Gang

2014-03-01

To investigate the effect of different parts, harvesting time and processing technologies on alkaloids content of Coptis chinensis adventitious root. The content of alkaloids were analyzed by HPLC. The content of total alkaloids in adventitious root harvested in different time was ranged from 2.5% to 2.9%, in which that of berberine and coptisine were the highest, reaching to 1%, and that of palmatine was only 0.1%. It suggested there was no significant difference of total alkaloids at different harvesting time. Nevertheless, the difference of the alkaloids content from different parts was much significant. The content of total alkaloid of adventitious root near to rhizome was about 4%, 2 times higher than that away from rhizome (only 2%). In addition, different processing technologies would affect alkaloids content obviously. There was hardly loss of alkaloids when the fresh adventitious root was washed with water, but it would decrease alkaloids content when the dried adventitious root was washed. Medicine value of Coptis chinensis adventitious root near to rhizome is higher than that away from rhizome. And fresh Coptis chinensis adventitious root can be washed with water.

Enantioselective copper-catalysed propargylic substitution: synthetic scope study and application in formal total syntheses of (+)-anisomycin and (-)-cytoxazone

NARCIS (Netherlands)

Detz, R.J.; Abiri, Z.; le Griel, R.; Hiemstra, H.; van Maarseveen, J.H.

2011-01-01

A copper catalyst with a chiral pyridine-2,6-bisoxazoline (pybox) ligand was used to convert a variety of propargylic esters with different side chains (R=Ar, Bn, alkyl) into their amine counterparts in very high yields and with good enantioselectivities (up to 90 % enantiomeric excess (ee)).

Enantioselective addition of nitrones to activated cyclopropanes.

Science.gov (United States)

Sibi, Mukund P; Ma, Zhihua; Jasperse, Craig P

2005-04-27

In this paper, we demonstrate the first examples of chiral Lewis acid catalysis in the formation of tetrahydro-1,2-oxazines with very high enantioselectivity starting with diactivated cyclopropanes and nitrones (>90% yields and ee). Reactions with racemic substituted cyclopropanes provide approximately 1:1 diastereomeric tetrahydro-1,2-oxazine products with high enantioselectivity. Mechanistic information for the formation of the tetrahydro-1,2-oxazines is also detailed.

Enantioselective Biotransformation of Chiral Persistent Organic Pollutants.

Science.gov (United States)

Zhang, Ying; Ye, Jing; Liu, Min

2017-01-01

Enantiomers of chiral compounds commonly undergo enantioselective transformation in most biologically mediated processes. As chiral persistent organic pollutants (POPs) are extensively distributed in the environment, differences between enantiomers in biotransformation should be carefully considered to obtain exact enrichment and specific health risks. This review provides an overview of in vivo biotransformation of chiral POPs currently indicated in the Stockholm Convention and their chiral metabolites. Peer-reviewed journal articles focused on the research question were thoroughly searched. A set of inclusion and exclusion criteria were developed to identify relevant studies. We mainly compared the results from different animal models under controlled laboratory conditions to show the difference between enantiomers in terms of distinct transformation potential. Interactions with enzymes involved in enantioselective biotransformation, especially cytochrome P450 (CYP), were discussed. Further research areas regarding this issue were proposed. Limited evidence for a few POPs has been found in 30 studies. Enantioselective biotransformation of α-hexachlorocyclohexane (α-HCH), chlordane, dichlorodiphenyltrichloroethane (DDT), heptachlor, hexabromocyclododecane (HBCD), polychlorinated biphenyls (PCBs), and toxaphene, has been investigated using laboratory mammal, fish, bird, and worm models. Tissue and excreta distributions, as well as bioaccumulation and elimination kinetics after administration of racemate and pure enantiomers, have been analyzed in these studies. Changes in enantiomeric fractions have been considered as an indicator of enantioselective biotransformation of chiral POPs in most studies. Results of different laboratory animal models revealed that chiral POP biotransformation is seriously affected by chirality. Pronounced results of species-, tissue-, gender-, and individual-dependent differences are observed in in vivo biotransformation of chiral POPs

Stereoselective total syntheses of three Lycopodium alkaloids, (-)-magellanine, (+)-magellaninone, and (+)-paniculatine, based on two Pauson-Khand reactions.

Science.gov (United States)

Kozaka, Takashi; Miyakoshi, Naoki; Mukai, Chisato

2007-12-21

The total syntheses of (-)-magellanine, (+)-magellaninone, and (+)-paniculatine were completed from diethyl l-tartrate via the common intermediate in a stereoselective manner. The crucial steps in these syntheses involved two intramolecular Pauson-Khand reactions of enynes: the first Pauson-Khand reaction constructed the bicyclo[4.3.0] carbon framework, the corresponding A and B rings of these alkaloids in a highly stereoselective manner, whereas the second Pauson-Khand reaction stereoselectively produced the bicyclo[3.3.0]skeleton, which could be converted into the C and D rings of the target natural products.

Alkaloids in bufonid toads (melanophryniscus): temporal and geographic determinants for two argentinian species.

Science.gov (United States)

Daly, J W; Wilham, J M; Spande, T F; Garraffo, H M; Gil, R R; Silva, G L; Vaira, M

2007-04-01

Bufonid toads of the genus Melanophryniscus represent one of several lineages of anurans with the ability to sequester alkaloids from dietary arthropods for chemical defense. The alkaloid profile for Melanophryniscus stelzneri from a location in the province of Córdoba, Argentina, changed significantly over a 10-year period, probably indicating changes in availability of alkaloid-containing arthropods. A total of 29 alkaloids were identified in two collections of this population. Eight alkaloids were identified in M. stelzneri from another location in the province of Córdoba. The alkaloid profiles of Melanophryniscus rubriventris collected from four locations in the provinces of Salta and Jujuy, Argentina, contained 44 compounds and differed considerably between locations. Furthermore, alkaloid profiles of M. stelzneri and M. rubriventris strongly differed, probably reflecting differences in the ecosystem and hence in availability of alkaloid-containing arthropods.

Bidirectional enantioselective effects of the GABAB receptor agonist baclofen in two mouse models of excessive ethanol consumption.

Science.gov (United States)

Kasten, Chelsea R; Blasingame, Shelby N; Boehm, Stephen L

2015-02-01

The GABAB receptor agonist baclofen has been studied extensively in preclinical models of alcohol-use disorders, yet results on its efficacy have been uncertain. Racemic baclofen, which is used clinically, can be broken down into separate enantiomers of the drug. Baclofen has been shown to produce enantioselective effects in behavioral assays, including those modeling reflexive and sexual behavior. The current studies sought to characterize the enantioselective effects of baclofen in two separate models of ethanol consumption. The first was a Drinking-in-the-Dark procedure that provides "binge-like" ethanol access to mice by restricting access to a 2-h period, 3 h into the dark cycle. The second was a two-bottle choice procedure that utilized selectively bred High Alcohol Preferring 1 (HAP1) mice to model chronic ethanol access. HAP1 mice are selectively bred to consume pharmacologically relevant amounts of ethanol in a 24-h two-bottle choice paradigm. The results showed that baclofen yields enantioselective effects on ethanol intake in both models, and that these effects are bidirectional. Total ethanol intake was decreased by R(+)-baclofen, while total intake was increased by S(-)-baclofen in the binge-like and chronic drinking models. Whereas overall binge-like saccharin intake was significantly reduced by R(+)-baclofen, chronic intake was not significantly altered. S(-)-baclofen did not significantly alter saccharin intake. Neither enantiomer significantly affected locomotion during binge-like reinforcer consumption. Collectively, these results demonstrate that baclofen produces enantioselective effects on ethanol consumption. More importantly, the modulation of consumption is bidirectional. The opposing enantioselective effects may explain some of the variance seen in published baclofen literature. Copyright © 2015 Elsevier Inc. All rights reserved.

Enantioselective Effects of Metalaxyl Enantiomers on Breast Cancer Cells Metabolic Profiling Using HPLC-QTOF-Based Metabolomics

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Ping Zhang

2017-01-01

Full Text Available In this study, an integrative high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (HPLC-QTOF based metabolomics approach was performed to evaluate the enantioselective metabolic perturbations in MCF-7 cells after treatment with R-metalaxyl and S-metalaxyl, respectively. Untargeted metabolomics profile, multivariate pattern recognition, metabolites identification, and pathway analysis were determined after metalaxyl enantiomer exposure. Principal component analysis (PCA and partitial least-squares discriminant analysis (PLS-DA directly reflected the enantioselective metabolic perturbations induced by metalaxyl enantiomers. On the basis of multivariate statistical results, a total of 49 metabolites including carbohydrates, amino acids, nucleotides, fatty acids, organic acids, phospholipids, indoles, derivatives, etc. were found to be the most significantly changed metabolites and metabolic fluctuations caused by the same concentration of R-metalaxyl and S-metalaxyl were enantioselective. Pathway analysis indicated that R-metalaxyl and S-metalaxyl mainly affected the 7 and 10 pathways in MCF-7 cells, respectively, implying the perturbed pathways induced by metalaxyl enantiomers were also enantioselective. Furthermore, the significantly perturbed metabolic pathways were highly related to energy metabolism, amino acid metabolism, lipid metabolism, and antioxidant defense. Such results provide more specific insights into the enantioselective metabolic effects of chiral pesticides in breast cancer progression, reveal the underlying mechanisms, and provide available data for the health risk assessments of chiral environmental pollutants at the molecular level.

Enantioselective cyclizations and cyclization cascades of samarium ketyl radicals

Science.gov (United States)

Kern, Nicolas; Plesniak, Mateusz P.; McDouall, Joseph J. W.; Procter, David J.

2017-12-01

The rapid generation of molecular complexity from simple starting materials is a key challenge in synthesis. Enantioselective radical cyclization cascades have the potential to deliver complex, densely packed, polycyclic architectures, with control of three-dimensional shape, in one step. Unfortunately, carrying out reactions with radicals in an enantiocontrolled fashion remains challenging due to their high reactivity. This is particularly the case for reactions of radicals generated using the classical reagent, SmI2. Here, we demonstrate that enantioselective SmI2-mediated radical cyclizations and cascades that exploit a simple, recyclable chiral ligand can convert symmetrical ketoesters to complex carbocyclic products bearing multiple stereocentres with high enantio- and diastereocontrol. A computational study has been used to probe the origin of the enantioselectivity. Our studies suggest that many processes that rely on SmI2 can be rendered enantioselective by the design of suitable ligands.

Graphene-based hybrid for enantioselective sensing applications.

Science.gov (United States)

Zor, Erhan; Morales-Narváez, Eden; Alpaydin, Sabri; Bingol, Haluk; Ersoz, Mustafa; Merkoçi, Arben

2017-01-15

Chirality is a major field of research of chemical biology and is essential in pharmacology. Accordingly, approaches for distinguishing between different chiral forms of a compound are of great interest. We report on an efficient and generic enantioselective sensor that is achieved by coupling reduced graphene oxide with γ-cyclodextrin (rGO/γ-CD). The enantioselective sensing capability of the resulting structure was operated in both electrical and optical mode for of tryptophan enantiomers (D-/L-Trp). In this sense, voltammetric and photoluminescence measurements were conducted and the experimental results were compared to molecular docking method. We gain insight into the occurring recognition mechanism with selectivity toward D- and L-Trp as shown in voltammetric, photoluminescence and molecular docking responses. As an enantioselective solid phase on an electrochemical transducer, thanks to the different dimensional interaction of enantiomers with hybrid material, a discrepancy occurs in the Gibbs free energy leading to a difference in oxidation peak potential as observed in electrochemical measurements. The optical sensing principle is based on the energy transfer phenomenon that occurs between photoexcited D-/L-Trp enantiomers and rGO/γ-CD giving rise to an enantioselective photoluminescence quenching due to the tendency of chiral enantiomers to form complexes with γ-CD in different molecular orientations as demonstrated by molecular docking studies. The approach, which is the first demonstration of applicability of molecular docking to show both enantioselective electrochemical and photoluminescence quenching capabilities of a graphene-related hybrid material, is truly new and may have broad interest in combination of experimental and computational methods for enantiosensing of chiral molecules. Copyright © 2016 Elsevier B.V. All rights reserved.

Infrared-thermographic screening of the activity and enantioselectivity of enzymes.

Science.gov (United States)

Reetz, M T; Hermes, M; Becker, M H

2001-05-01

The infrared radiation caused by the heat of reaction of an enantioselective enzyme-catalyzed transformation can be detected by modern photovoltaic infrared (IR)-thermographic cameras equipped with focal-plane array detectors. Specifically, in the lipase-catalyzed enantioselective acylation of racemic 1-phenylethanol, the (R)- and (S)-substrates are allowed to react separately in the wells of microtiter plates, the (R)-alcohol showing hot spots in the IR-thermographic images. Thus, highly enantioselective enzymes can be identified at kinetic resolution.

DNA-based catalytic enantioselective intermolecular oxa-Michael addition reactions

NARCIS (Netherlands)

Megens, Rik P.; Roelfes, Gerard

2012-01-01

Using the DNA-based catalysis concept, a novel Cu(II) catalyzed enantioselective oxa-Michael addition of alcohols to enones is reported. Enantioselectivities of up to 86% were obtained. The presence of water is important for the reactivity, possibly by reverting unwanted side reactions such as

Enantioselective Total Synthesis of Antibiotic CJ-16,264, Synthesis and Biological Evaluation of Designed Analogues, and Discovery of Highly Potent and Simpler Antibacterial Agents.

Science.gov (United States)

Nicolaou, K C; Pulukuri, Kiran Kumar; Rigol, Stephan; Buchman, Marek; Shah, Akshay A; Cen, Nicholas; McCurry, Megan D; Beabout, Kathryn; Shamoo, Yousif

2017-11-08

An improved and enantioselective total synthesis of antibiotic CJ-16,264 through a practical kinetic resolution and an iodolactonization reaction to form the iodo pyrrolizidinone fragment of the molecule is described. A series of racemic and enantiopure analogues of CJ-16,264 was designed and synthesized through the developed synthetic technologies and tested against drug-resistant bacterial strains. These studies led to interesting structure-activity relationships and the identification of a number of simpler, and yet equipotent, or even more potent, antibacterial agents than the natural product, thereby setting the foundation for further investigations in the quest for new anti-infective drugs.

Synergistic effects on enantioselectivity of zwitterionic chiral stationary phases for separations of chiral acids, bases, and amino acids by HPLC.

Science.gov (United States)

Hoffmann, Christian V; Pell, Reinhard; Lämmerhofer, Michael; Lindner, Wolfgang

2008-11-15

In an attempt to overcome the limited applicability scope of earlier proposed Cinchona alkaloid-based chiral weak anion exchangers (WAX) and recently reported aminosulfonic acid-based chiral strong cation exchangers (SCX), which are conceptionally restricted to oppositely charged solutes, their individual chiral selector (SO) subunits have been fused in a combinatorial synthesis approach into single, now zwitterionic, chiral SO motifs. The corresponding zwitterionic ion-exchange-type chiral stationary phases (CSPs) in fact combined the applicability spectra of the parent chiral ion exchangers allowing for enantioseparations of chiral acids and amine-type solutes in liquid chromatography using polar organic mode with largely rivaling separation factors as compared to the parent WAX and SCX CSPs. Furthermore, the application spectrum could be remarkably expanded to various zwitterionic analytes such as alpha- and beta-amino acids and peptides. A set of structurally related yet different CSPs consisting of either a quinine or quinidine alkaloid moiety as anion-exchange subunit and various chiral or achiral amino acids as cation-exchange subunits enabled us to derive structure-enantioselectivity relationships, which clearly provided strong unequivocal evidence for synergistic effects of the two oppositely charged ion-exchange subunits being involved in molecular recognition of zwitterionic analytes by zwitterionic SOs driven by double ionic coordination.

Development of Environment-Friendly Insecticides Based on Enantioselectivity: Bifenthrin as a Case.

Science.gov (United States)

Qian, Yi; Zhou, Peixue; Zhang, Quan

2017-01-01

Chiral insecticides significantly contribute to the environmental pollutions recently. As the development of industry and agriculture, increasing number of chiral insecticides are to be introduced into the market. However, their enantioselective toxicology to ecosystem still remains uncertain. In this review, we embarked on a structured search of bibliographic databases for peer-reviewed articles regarding the enantioselective effects of bifenthrin, a typical chiral insecticide, on both target and non-target species. With this enantioselective property of chiral insecticides, they often exhibit adverse effects on non-target species enantioselectively. Specifically, the enantioselective effects of bifenthrin on target and non-target organisms were discussed. In target species, R-bifenthrin exerts more significant activities in deinsectization, compared with S-bifenthrin. On the other hand, Sbifenthrin is more toxic to non-target species than R-bifenthrin, which suggests that the application of sole enantiomer is more efficient and environment-friendly than that of racemate. This review confirms the choice of environment-friendly insecticides from the perspective of the enantioselectivity of chiral insecticides. To make insecticides more efficient to target species and less toxic to non-target species, further research should be done to investigated the potential effects of targetactive enantiomers on non-target organisms as well as the enantioselective fate of enantiomers in multiple environmental matrix.

Rhodium(II)-catalyzed enantioselective synthesis of troponoids.

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Murarka, Sandip; Jia, Zhi-Jun; Merten, Christian; Daniliuc, Constantin-G; Antonchick, Andrey P; Waldmann, Herbert

2015-06-22

We report a rhodium(II)-catalyzed highly enantioselective 1,3-dipolar cycloaddition reaction between the carbonyl moiety of tropone and carbonyl ylides to afford troponoids in good to high yields with excellent enantioselectivity. We demonstrate that α-diazoketone-derived carbonyl ylides, in contrast to carbonyl ylides derived from diazodiketoesters, undergo [6+3] cycloaddition reactions with tropone to yield the corresponding bridged heterocycles with excellent stereoselectivity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Computer-Assisted Design and Synthetic Applications of Chiral Enol Borinates: Novel, Highly Enantioselective Aldol Reagents

Directory of Open Access Journals (Sweden)

Gennari Cesare

1998-01-01

Full Text Available We have recently described the development of a quantitative transition state model for the prediction of stereoselectivity in the boron-mediated aldol reaction. This model provides qualitative insights into the factors contributing to the stereochemical outcome of a variety of reactions of synthetic importance. The force field model was used to assist the design and preparation of new chiral boron ligands derived from menthone. The chiral boron enolates were employed in various stereoselective processes, including the addition to chiral aldehydes and the reagent-controlled total synthesis of (3S,4S-statine. The chiral enolates derived from alpha-halo and alpha-oxysubstituted thioacetates were added to aldehydes and imines. Addition to imines leads to the enantioselective synthesis of chiral aziridines, a formal total synthesis of (+-thiamphenicol, and a new highly efficient synthesis of the paclitaxel (taxol® C-13 side-chain and taxol semisynthesis from baccatin III. The stereochemical outcome of the addition to imines was rationalised with the aid of computational studies. Enantioselective addition reactions of the chiral boron enolate derived from thioacetate have successfully been applied to solid phase bound aldehydes to give aldol products in comparable yields and enantioselectivities to the usual solution conditions.

Enantioselective synthesis of α-oxy amides via Umpolung amide synthesis.

Science.gov (United States)

Leighty, Matthew W; Shen, Bo; Johnston, Jeffrey N

2012-09-19

α-Oxy amides are prepared through enantioselective synthesis using a sequence beginning with a Henry addition of bromonitromethane to aldehydes and finishing with Umpolung Amide Synthesis (UmAS). Key to high enantioselection is the finding that ortho-iodo benzoic acid salts of the chiral copper(II) bis(oxazoline) catalyst deliver both diastereomers of the Henry adduct with high enantiomeric excess, homochiral at the oxygen-bearing carbon. Overall, this approach to α-oxy amides provides an innovative complement to alternatives that focus almost entirely on the enantioselective synthesis of α-oxy carboxylic acids.

Influence of biochar on the enantioselective behavior of the chiral fungicide metalaxyl in soil

Science.gov (United States)

Gámiz, Beatriz; Pignatello, Joseph J.; Hermosín, María Carmen; Cox, Lucía; Celis, Rafael

2015-04-01

columns was recovered in leachates, in contrast to significantly higher percentages leachedin unamended soil, being the process more enantioselective in the latter case. Finally, total recoveries of both enantiomers were greater for BC-amended soil columns than for unamended soil columns, indicating reduced degradation in BC- amended soil. Our findings illustrated the ability of biochar to modify the enantioselectivity behavior of metalaxyl in soil by its high sorption capacity. BC could contribute to reduce the current agronomic doses used for chiral pesticides to deplete the contamination problems associated with their use, and also to act as an immobilizing amendment in soil remediation strategies. Acknowledgments: MINECO (AGL2011-23779), FACCE-JPI (Designchar4food), JA (AGR-264) and FEDER-FSE (OP 2007-2013).

Copper(II)-catalyzed exo and enantioselective cycloadditions of azomethine imines.

Science.gov (United States)

Sibi, Mukund P; Rane, Digamber; Stanley, Levi M; Soeta, Takahiro

2008-07-17

A strategy for exo and enantioselective 1,3-dipolar cycloaddition of azomethine imines to 2-acryloyl-3-pyrazolidinone is described. The corresponding cycloadducts are isolated with high diastereoselectivities (up to >96:4 exo/endo) and enantioselectivities (up to 98% ee).

[Effects of steaming and baking on content of alkaloids in Aconite Lateralis Radix (Fuzi)].

Science.gov (United States)

Yang, Chang-lin; Huang, Zhi-fang; Zhang, Yi-han; Liu, Yu-hong; Liu, Yun-huan; Chen, Yan; Yi, Jin-hai

2014-12-01

To study the effect of steaming and baking process on contents of alkaloids in Aconite Lateralis Radix (Fuzi), 13 alkaloids were analyzed by UPLC-MS/MS equipped with ESI ion source in MRM mode. In steaming process, the contents of diester-diterpenoid alkaloids decreased rapidly, the contents of monoester-diterpenoid alkaloids firstly increased, reached the peak at 40 min, and then deceased gradually. The contents of aconine alkaloids (mesaconine, aconine and hypaconine) increased all the time during processing, while the contents of fuziline, songorine, karacoline, salsolionl were stable or slightly decreased. In baking process, dynamic variations of alkaloids were different from that in the steaming process. Diester-diterpenoid alkaloids were degraded slightly slower than in steaming process. Monoester-diterpenoid alkaloids, aconine alkaloids and the total alkaloids had been destroyed at different degrees, their contents were significantly lower than the ones in steaming Fuzi at the same processing time. This experiment revealed the dynamic variations of alkaloids in the course of steaming and baking. Two processing methods which can both effectively remove the toxic ingredients and retain the active ingredients are simple and controllable, and are valuable for popularization and application.

Efficient and highly enantioselective formation of the all-carbon quaternary stereocentre of lyngbyatoxin A

DEFF Research Database (Denmark)

Vital, Paulo J.V.; Tanner, David

2006-01-01

Indole 25, an advanced intermediate in a projected enantioselective total synthesis of lyngbyatoxin A 1, was prepared from allylic alcohol 11 in 9 steps and >95% ee, key transformations being the enantiospecific rearrangement of vinyl epoxide 14 and the Hemetsberger-Knittel reaction of azide 24....

Genetic variation of piperidine alkaloids in Pinus ponderosa: a common garden study.

Science.gov (United States)

Gerson, Elizabeth A; Kelsey, Rick G; St Clair, J Bradley

2009-02-01

Previous measurements of conifer alkaloids have revealed significant variation attributable to many sources, environmental and genetic. The present study takes a complementary and intensive, common garden approach to examine genetic variation in Pinus ponderosa var. ponderosa alkaloid production. Additionally, this study investigates the potential trade-off between seedling growth and alkaloid production, and associations between topographic/climatic variables and alkaloid production. Piperidine alkaloids were quantified in foliage of 501 nursery seedlings grown from seed sources in west-central Washington, Oregon and California, roughly covering the western half of the native range of ponderosa pine. A nested mixed model was used to test differences among broad-scale regions and among families within regions. Alkaloid concentrations were regressed on seedling growth measurements to test metabolite allocation theory. Likewise, climate characteristics at the seed sources were also considered as explanatory variables. Quantitative variation from seedling to seedling was high, and regional variation exceeded variation among families. Regions along the western margin of the species range exhibited the highest alkaloid concentrations, while those further east had relatively low alkaloid levels. Qualitative variation in alkaloid profiles was low. All measures of seedling growth related negatively to alkaloid concentrations on a natural log scale; however, coefficients of determination were low. At best, annual height increment explained 19.4 % of the variation in ln(total alkaloids). Among the climate variables, temperature range showed a negative, linear association that explained 41.8 % of the variation. Given the wide geographic scope of the seed sources and the uniformity of resources in the seedlings' environment, observed differences in alkaloid concentrations are evidence for genetic regulation of alkaloid secondary metabolism in ponderosa pine. The theoretical

A strategy for complex dimer formation when biomimicry fails: total synthesis of ten coccinellid alkaloids.

Science.gov (United States)

Sherwood, Trevor C; Trotta, Adam H; Snyder, Scott A

2014-07-09

Although dimeric natural products can often be synthesized in the laboratory by directly merging advanced monomers, these approaches sometimes fail, leading instead to non-natural architectures via incorrect unions. Such a situation arose during our studies of the coccinellid alkaloids, when attempts to directly dimerize Nature's presumed monomeric precursors in a putative biomimetic sequence afforded only a non-natural analogue through improper regiocontrol. Herein, we outline a unique strategy for dimer formation that obviates these difficulties, one which rapidly constructs the coccinellid dimers psylloborine A and isopsylloborine A through a terminating sequence of two reaction cascades that generate five bonds, five rings, and four stereocenters. In addition, a common synthetic intermediate is identified which allows for the rapid, asymmetric formal or complete total syntheses of eight monomeric members of the class.

Calcium(ii)-catalyzed enantioselective conjugate additions of amines.

Science.gov (United States)

Uno, Brice E; Dicken, Rachel D; Redfern, Louis R; Stern, Charlotte M; Krzywicki, Greg G; Scheidt, Karl A

2018-02-14

The direct enantioselective chiral calcium(ii)·phosphate complex (Ca[CPA] 2 )-catalyzed conjugate addition of unprotected alkyl amines to maleimides was developed. This mild catalytic system represents a significant advance towards the general convergent asymmetric amination of α,β-unsaturated electrophiles, providing medicinally relevant chiral aminosuccinimide products in high yields and enantioselectivities. Furthermore, the catalyst can be reused directly from a previously chromatographed reaction and still maintain both high yield and selectivity.

Nickel-catalyzed regio- and enantioselective aminolysis of 3,4-epoxy alcohols.

Science.gov (United States)

Wang, Chuan; Yamamoto, Hisashi

2015-04-08

The first catalytic regio- and enantioselective aminolysis of 3,4-epoxy alcohols has been accomplished. Under the catalysis of Ni(ClO4)2·6H2O, the C4 selective ring opening of various 3,4-epoxy alcohols proceeded in a stereospecific manner with high regioselectivities. Furthermore, with the Ni-BINAM catalytic system the enantioselective ring opening of 3,4-epoxy alcohols furnished various γ-hydroxy-δ-amino alcohols as products with complete regiocontrol and high enantioselectivities (up to 94% ee).

Fluxional additives: a second generation control in enantioselective catalysis.

Science.gov (United States)

Sibi, Mukund P; Manyem, Shankar; Palencia, Hector

2006-10-25

The concept of "fluxional additives", additives that can adopt enantiomeric conformations depending on the chiral information in the ligand, is demonstrated in enantioselective Diels-Alder and nitrone cycloaddition reactions. The additive design is modular, and diverse structures are accessible in three steps. Chiral Lewis acids from main group and transition metals show enhancements in enantioselectivity in the presence of these additives.

Engineering an enantioselective amine oxidase for the synthesis of pharmaceutical building blocks and alkaloid natural products.

Science.gov (United States)

Ghislieri, Diego; Green, Anthony P; Pontini, Marta; Willies, Simon C; Rowles, Ian; Frank, Annika; Grogan, Gideon; Turner, Nicholas J

2013-07-24

The development of cost-effective and sustainable catalytic methods for the production of enantiomerically pure chiral amines is a key challenge facing the pharmaceutical and fine chemical industries. This challenge is highlighted by the estimate that 40-45% of drug candidates contain a chiral amine, fueling a demand for broadly applicable synthetic methods that deliver target structures in high yield and enantiomeric excess. Herein we describe the development and application of a "toolbox" of monoamine oxidase variants from Aspergillus niger (MAO-N) which display remarkable substrate scope and tolerance for sterically demanding motifs, including a new variant, which exhibits high activity and enantioselectivity toward substrates containing the aminodiphenylmethane (benzhydrylamine) template. By combining rational structure-guided engineering with high-throughput screening, it has been possible to expand the substrate scope of MAO-N to accommodate amine substrates containing bulky aryl substituents. These engineered MAO-N biocatalysts have been applied in deracemization reactions for the efficient asymmetric synthesis of the generic active pharmaceutical ingredients Solifenacin and Levocetirizine as well as the natural products (R)-coniine, (R)-eleagnine, and (R)-leptaflorine. We also report a novel MAO-N mediated asymmetric oxidative Pictet-Spengler approach to the synthesis of (R)-harmicine.

Catalytic enantioselective Reformatsky reaction with ketones

NARCIS (Netherlands)

Fernandez-Ibanez, M. Angeles; Macia, Beatriz; Minnaard, Adriaan J.; Feringa, Ben L.

2008-01-01

Chiral tertiary alcohols were obtained with good yields and enantioselectivities via a catalytic Reformatsky reaction with ketones, including the challenging diaryl ketones, using chiral BINOL derivatives.

Inhibitive action of alkaloids and non alkaloid fractions of the ...

African Journals Online (AJOL)

The corrosion inhibition of mild steel in 2.0 MHCl solution by non-alkaloidal and alkaloidal fractions of the extracts of Phyllanthus amarus (NAEPA and AEPA respectively) was studied using gravimetric and gasometric techniques at 303 and 323 K. The results revealed that the extracts functioned as good corrosion inhibitors.

Correlations between Antioxidant Activity and Alkaloids and Phenols of Maca (Lepidium meyenii

Directory of Open Access Journals (Sweden)

Jin Gan

2017-01-01

Full Text Available The antioxidant capacity of maca has been considered to be the basis for other bioactivities, and revealing the active antioxidant compounds would help to elucidate a variety of bioactive compounds. In this study, the correlation between the antioxidant activity of maca and secondary metabolites, including ferric reducing antioxidant potential (FRAP, hydroxyl radical scavenging ability (HRSA, lipid peroxidation inhibition ability (LPIA, total phenolic contents (TPCs, total alkaloid contents (TACs, and total sterol contents (TSCs, was investigated by measuring. Chloroform was selected to be an efficient extraction solvent for antioxidant compounds in maca by polarity fractions test. The results showed that TPC exhibited significant linear correlations (P<0.05 to FRAP and LPIA, while TAC had significant linear correlations (P<0.05 to FRAP, HRSA, and LPIA. These results suggested that alkaloids and phenols were the most important substances for the antioxidation of maca, of which the antioxidant effect of alkaloids seemed to be higher than that of phenols.

Cyclopalladated complexes in enantioselective catalysis

Energy Technology Data Exchange (ETDEWEB)

Dunina, Valeria V; Gorunova, Olga N; Zykov, P A; Kochetkov, Konstantin A

2011-01-31

The results of the use of optically active palladacycles in enantioselective catalysis of [3,3]-sigmatropic rearrangements, aldol condensation, the Michael reaction and cross-coupling are analyzed. Reactions with allylic substrates or reagents and some other transformations are considered.

Integrative assessment of enantioselectivity in endocrine disruption and immunotoxicity of synthetic pyrethroids

Energy Technology Data Exchange (ETDEWEB)

Zhao Meirong [Research Center of Environmental Science, College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032 (China); Chen Fang [College of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018 (China); Wang Cui; Zhang Quan [Research Center of Environmental Science, College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032 (China); Gan Jianying [Department of Environmental Sciences, University of California, Riverside, CA 92521 (United States); Liu Weiping, E-mail: wliu@zjut.edu.c [Research Center of Environmental Science, College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032 (China)

2010-05-15

The increasing release of chiral chemicals into the environment dictates attention to a better understanding of enantioselectivity in their human and ecotoxicological effects. Although enantioselectivity has been considered in many recent studies, there is little effort for discerning the connection between different processes, and as such, our current knowledge about chiral contaminants is rather scattered and incoherent. In this study, we simultaneously evaluated enantioselectivity of two chiral pesticides, lambda-cyhalothrin (LCT) and (Z)-cis-bifenthrin (cis-BF), in immunotoxicity to macrophage cells (RAW264.7), and endocrine disruption activity in human breast carcinoma cell line MCF-7. Analysis of cell proliferation, cell viability, apoptosis, and receptor gene expression showed significant differences between the enantiomers of LCT or cis-BF in estrogenic potential and immunocytotoxicity. The selectivity in these effects consistently followed the same direction, with (-)-LCT or 1S-cis-BF displaying a greater activity than its counterpart. The consistency was attributed to interplaying mechanisms in the closely interacting immune and endocrine systems. The underlying interplays suggest that other chiral xenobiotics may also show a directional enantioselectivity in immunotoxicity and endocrine toxicity. Given that many biological processes are inter-related, enantioselectivity may follow specific patterns that can be revealed via integrative assessments as demonstrated in this study. - Chiral contaminants should consider multiple effects and relate directions of enantioselectivity to their interplaying processes.

Integrative assessment of enantioselectivity in endocrine disruption and immunotoxicity of synthetic pyrethroids

International Nuclear Information System (INIS)

Zhao Meirong; Chen Fang; Wang Cui; Zhang Quan; Gan Jianying; Liu Weiping

2010-01-01

The increasing release of chiral chemicals into the environment dictates attention to a better understanding of enantioselectivity in their human and ecotoxicological effects. Although enantioselectivity has been considered in many recent studies, there is little effort for discerning the connection between different processes, and as such, our current knowledge about chiral contaminants is rather scattered and incoherent. In this study, we simultaneously evaluated enantioselectivity of two chiral pesticides, lambda-cyhalothrin (LCT) and (Z)-cis-bifenthrin (cis-BF), in immunotoxicity to macrophage cells (RAW264.7), and endocrine disruption activity in human breast carcinoma cell line MCF-7. Analysis of cell proliferation, cell viability, apoptosis, and receptor gene expression showed significant differences between the enantiomers of LCT or cis-BF in estrogenic potential and immunocytotoxicity. The selectivity in these effects consistently followed the same direction, with (-)-LCT or 1S-cis-BF displaying a greater activity than its counterpart. The consistency was attributed to interplaying mechanisms in the closely interacting immune and endocrine systems. The underlying interplays suggest that other chiral xenobiotics may also show a directional enantioselectivity in immunotoxicity and endocrine toxicity. Given that many biological processes are inter-related, enantioselectivity may follow specific patterns that can be revealed via integrative assessments as demonstrated in this study. - Chiral contaminants should consider multiple effects and relate directions of enantioselectivity to their interplaying processes.

Catharanthus alkaloids XXXII: isolation of alkaloids from Catharanthus trichophyllus roots and structure elucidation of cathaphylline.

Science.gov (United States)

Cordell, G A; Farnsworth, N R

1976-03-01

Further examination of the cytotoxic alkaloid fractions of Catharanthus trichophyllus roots afforded nine alkaloids. Two of these alkaloids, lochnericine and horhammericine, are responsible for part of the cytotoxic activity. The structure elucidation of cathaphylline, a new beta-anilino acrylate derivative, is described.

Dietary alkaloid sequestration in a poison frog: an experimental test of alkaloid uptake in Melanophryniscus stelzneri (Bufonidae).

Science.gov (United States)

Hantak, Maggie M; Grant, Taran; Reinsch, Sherri; McGinnity, Dale; Loring, Marjorie; Toyooka, Naoki; Saporito, Ralph A

2013-12-01

Several lineages of brightly colored anurans independently evolved the ability to secrete alkaloid-containing defensive chemicals from granular glands in the skin. These species, collectively referred to as 'poison frogs,' form a polyphyletic assemblage that includes some species of Dendrobatidae, Mantellidae, Myobatrachidae, Bufonidae, and Eleutherodactylidae. The ability to sequester alkaloids from dietary arthropods has been demonstrated experimentally in most poison frog lineages but not in bufonid or eleutherodactylid poison frogs. As with other poison frogs, species of the genus Melanophryniscus (Bufonidae) consume large numbers of mites and ants, suggesting they might also sequester defensive alkaloids from dietary sources. To test this hypothesis, fruit flies dusted with alkaloid/nutritional supplement powder were fed to individual Melanophryniscus stelzneri in two experiments. In the first experiment, the alkaloids 5,8-disubstituted indolizidine 235B' and decahydroquinoline were administered to three individuals for 104 days. In the second experiment, the alkaloids 3,5-disubstituted indolizidine 239Q and decahydroquinoline were given to three frogs for 153 days. Control frogs were fed fruit flies dusted only with nutritional supplement. Gas chromatography/mass spectrometry analyses revealed that skin secretions of all experimental frogs contained alkaloids, whereas those of all control frogs lacked alkaloids. Uptake of decahydroquinoline was greater than uptake of 5,8-disubstituted indolizidine, and uptake of 3,5-disubstituted indolizidine was greater than uptake of decahydroquinoline, suggesting greater uptake efficiency of certain alkaloids. Frogs in the second experiment accumulated a greater amount of alkaloid, which corresponds to the longer duration and greater number of alkaloid-dusted fruit flies that were consumed. These findings provide the first experimental evidence that bufonid poison frogs sequester alkaloid-based defenses from dietary

Enantioselective Cytotoxicity Profile of o,p’-DDT in PC 12 Cells

Science.gov (United States)

Zhang, Chunlong; Wen, Yuezhong; Liu, Weiping

2012-01-01

Background The continued uses of dichlordiphenyltrichloroethane (DDT) for indoor vector control in some developing countries have recently fueled intensive debates toward the global ban of this persistent legacy contaminant. Current approaches for ecological and health risk assessment has ignored the chiral nature of DDT. In this study by employing an array of cytotoxicity related endpoints, we investigated the enantioselective cytotoxicity of o,p’-DDT. Principal Findings we demonstrated for the first time that R-(−)-o,p’-DDT caused more neuron cell death by inducing more severe oxidative stress, which selectively imbalanced the transcription of stress-related genes (SOD1, SOD2, HSP70) and enzyme (superoxide dismutase and lactate dehydrogenase) activities, and greater cellular apoptosis compared to its enantiomer S-(+)-o,p’-DDT at the level comparable to malaria area exposure (parts per million). We further elucidated enantioselective modes of action using microarray combined with enzyme-linked immunosorbent assay. The enantioselective apoptosis might involve three signaling pathways via caspase 3, tumor protein 53 (p53) and NFkB. Conclusions Based on DDT stereochemistry and results reported for other chiral pesticides, our results pointed to the same directional enantioselectivity of chiral DDT toward mammalian cells. We proposed that risk assessment on DDT should consider the enantiomer ratio and enantioselectivities. PMID:22937105

Enantioselective carbenoid insertion into C(sp3–H bonds

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J. V. Santiago

2016-05-01

Full Text Available The enantioselective carbenoid insertion into C(sp3–H bonds is an important tool for the synthesis of complex molecules due to the high control of enantioselectivity in the formation of stereogenic centers. This paper presents a brief review of the early issues, related mechanistic studies and recent applications on this chemistry area.

Enantioselective Copper-Catalyzed Oxy-Alkynylation of Diazo Compounds.

Science.gov (United States)

Hari, Durga Prasad; Waser, Jerome

2017-06-28

Enantioselective catalytic methods allowing the addition of both a nucleophile and an electrophile onto diazo compounds give a fast access into important building blocks. Herein, we report the highly enantioselective oxyalkynylation of diazo compounds using ethynylbenziodoxol-(on)e reagents and a simple copper bisoxazoline catalyst. The obtained α-benzoyloxy propargylic esters are useful building blocks, which are difficult to synthesize in enantiopure form using other methods. The obtained products could be efficiently transformed into vicinal diols and α-hydroxy propargylic esters without loss in enantiopurity.

Phytochemical screening, total phenolic, total flavonoids contents and antioxidant activity of cinchona ledgeriana leaves ethanol extract

Science.gov (United States)

Sundowo, Andini; Artanti, Nina; Hanafi, M.; Minarti, Primahana, Gian

2017-11-01

C ledgeriana is a medicinal plant that contains alkaloids, especially on the barks for commercial production of quinine as antimalarial. The main alkaloids in this plant are cinchonine, cinchonidine, quinine and quinidine. Besides for antiamalarial this plant is also commonly used to treat whooping cough, influenza and dysentery. Compare to other medicinal plants, nowadays only very few studies were conducted in Cinchona species. Our current study aims to determine the content of phytochemical, total phenol and total flavonoids from C. ledgeriana leaves 70% ethanol extract. The extraction was performed by maceration method using 70% ethanol solvent and then fractionated into hexane, ethylacetate and butanol. Phytochemical screening was performed to determine the content of alkaloids, flavonoids, terpenoids, tannins and saponins. Total phenol and flavonoid contents of the extract were determined by Folin-Ciocalteu and alumunium chloride colorimetric methods using gallic acid and quercetin as standards. The antioxidant activity was determined by using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. The results of phytochemical screening showed that the 70% ethanol extract of C. ledgeriana leaves contained alkaloids, flavonoids, terpenoids, tannins and saponins. The total phenol and total flavonoids analysis showed that ethyl acetate fraction had the highest total phenol (40.23%) and total flavonoids (65.34%).

Total Synthesis of Zoanthamine Alkaloids, Part 2. Construction of the C1-C5, C6-C10 and C11-C24 Fragments of Zoanthamine

DEFF Research Database (Denmark)

Tanner, David Ackland; Tedenborg, Lars; Somfai, Peter

1997-01-01

This paper describes the construction of three key intermediates for a projected total synthesis of the marine alkaloid zoanthamine. These building blocks, corresponding to the C1-C5, C6-C10 and C11-C24 fragments of the target molecule, are synthesised efficiently form (R...

RIA for indol alkaloids

International Nuclear Information System (INIS)

Arens, H.

1979-01-01

The technique of RIAs for indol alkaloids (ajmaline, ergotamine, ergocristine, ergometrine, and lysergic acid) is described, and applications for this RIA and the RIA for raubasine and serpentine are mentioned. The indol alkaloide RIAs are shown to be suitable both for alkaloid distribution measurements in Catharantus and Rauwolfia plants and C. purpurea sclerotia as well as for the selection of high-efficiency strains and the optimisation of cultures of plant tissues and saprophytic fungi. (orig./MG) [de

Protective Effects of Alkaloid Compounds from Nelumbinis Plumula on tert-Butyl Hydroperoxide-Induced Oxidative Stress

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Ze-Bin Guo

2013-08-01

Full Text Available This study was conducted to investigate the effect of Nelumbinis Plumula total alkaloid (NPA and its main alkaloid components on oxidative stress induced by tert-butyl hydroperoxide (t-BHP in the human hepatocellular HepG2 cell line. According to HPLC analysis, several major alkaloid compounds such as liensinine, isoliensinine and neferine were present in NPA. The cytotoxic effects in 0.55 mM t-BHP-induced HepG2 cells were significantly inhibited by NPA and the major compound in NPA, neferine, showed the strongest activities. The protective effect of neferine against oxidative stress induced by t-BHP may be associated with decreased ROS formation, TBARS generation, LDH release and increased GSH levels, suggesting their involvement of the cytoprotective on oxidative stress. The effects were comparable with quercetin, which was used as positive control. Overall, total alkaloid and alkaloid compounds from Nelumbinis Plumula displayed a significant cytoprotective effect against oxidative stress. Further study is needed to elucidate the relationship between the chemical structures of the components in NPA and their protective effect on oxidative stress.

Pentanidium-catalyzed enantioselective phase-transfer conjugate addition reactions

KAUST Repository

Ma, Ting

2011-03-09

A new chiral entity, pentanidium, has been shown to be an excellent chiral phase-transfer catalyst. The enantioselective Michael addition reactions of tert-butyl glycinate-benzophenone Schiff base with various α,β- unsaturated acceptors provide adducts with high enantioselectivities. A successful gram-scale experiment at a low catalyst loading of 0.05 mol % indicates the potential for practical applications of this methodology. Phosphoglycine ester analogues can also be utilized as the Michael donor, affording enantioenriched α-aminophosphonic acid derivatives and phosphonic analogues of (S)-proline. © 2011 American Chemical Society.

Evaluation of achiral templates with fluxional Brønsted basic substituents in enantioselective conjugate additions.

Science.gov (United States)

Adachi, Shinya; Takeda, Norihiko; Sibi, Mukund P

2014-12-19

Enantioselective conjugate addition of malononitrile to pyrazolidinone-derived enoates proceeds in excellent yields and high enantioselectivities. A comparison of fluxional substituents with and without a Brønsted basic site and their impact on selectivity is detailed. Molecular sieves as an additive were found to be essential to achieve high enantioselectivity.

Application of enantioselective radical reactions: synthesis of (+)-ricciocarpins A and B.

Science.gov (United States)

Sibi, Mukund P; He, Liwen

2004-05-27

Enantioselective synthesis of (+)-ricciocarpins A and B has been achieved in 41 and 45% overall yields, respectively, starting from a beta-substituted oxazolidinone. The key steps in the strategy are an enantioselective conjugate radical addition and the addition of a furyl organometallic to a key aldehyde intermediate. [reaction--see text

Flexible Enantioselectivity of Tryptophanase Attributable to Benzene Ring in Heterocyclic Moiety of D-Tryptophan

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Akihiko Shimada

2012-05-01

Full Text Available The invariance principle of enzyme enantioselectivity must be absolute because it is absolutely essential to the homochiral biological world. Most enzymes are strictly enantioselective, and tryptophanase is one of the enzymes with extreme absolute enantioselectivity for L-tryptophan. Contrary to conventional knowledge about the principle, tryptophanase becomes flexible to catalyze D-tryptophan in the presence of diammonium hydrogenphosphate. Since D-amino acids are ordinarily inert or function as inhibitors even though they are bound to the active site, the inhibition behavior of D-tryptophan and several inhibitors involved in this process was examined in terms of kinetics to explain the reason for this flexible enantioselectivity in the presence of diammonium hydrogenphosphate. Diammonium hydrogenphosphate gave tryptophanase a small conformational change so that D-tryptophan could work as a substrate. As opposed to other D-amino acids, D-tryptophan is a very bulky amino acid with a benzene ring in its heterocyclic moiety, and so we suggest that this structural feature makes the catalysis of D-tryptophan degradation possible, consequently leading to the flexible enantioselectivity. The present results not only help to understand the mechanism of enzyme enantioselectivity, but also shed light on the origin of homochirality.

New method for the study of Amaryllidaceae alkaloid biosynthesis using biotransformation of deuterium-labeled precursor in tissue cultures

International Nuclear Information System (INIS)

Tahchy, A. E.; Boisbrun, M.; Chretien, F.; Henry, M.; Chapleur, Y.; Laurain-Mattar, D.; Ptak, A.; Dupire, F.

2010-01-01

Biotransformation of deuterated-4'-O-methylnorbelladine into alkaloids galanthamine and lycorine in tissue cultures of Leucojum aestivum was demonstrated using HPLC coupled to mass spectrometry. GC-MS screening was also carried to investigate other native and deuterated alkaloids. A total of six labeled alkaloids were identified indicating that 4'-O-methyl-d3-norbelladine is incorporated into three different groups of Amaryllidaceae alkaloids that are biosynthesized by three modes of intramolecular oxidative phenol coupling. (authors)

Anticonvulsant properties of the total alkaloid fraction of Rauvolfia ligustrina Roem. et Schult. in male mice

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Lucindo J. Quintans-Júnior

Full Text Available Rauvolfia ligustrina Roem et. Schult (Apocynaceae, commonly known as "paratudo" and "arrebenta-boi" is a small tree found in Brazilian Northeastern. Previous studies have demonstrated depressant and anticonvulsant properties of the ethanol extract of Rauvolfia ligustrina. The aim of the present study was the determination of the lethal dose 50% (LD50 and the effects of total alkaloid fraction (TAF of the aerial parts of R. ligustrina in animal models of convulsion. It was found that the acute toxicity of TAF was 127.8 (112.5-145.2 mg/kg (i.p. in mice. TAF (20 mg/kg, ip significantly increased (p < 0.05 the latencies of clonic seizures induced by pentylenetetrazol (PTZ and picrotoxin (PIC. However, TAF did not protect the animals in maximal electroshock (MES induced seizures. These results suggest that TAF of R. ligustrina possesses anticonvulsant properties.

Enantioselective H-atom transfer reaction: a strategy to synthesize formaldehyde aldol products.

Science.gov (United States)

Sibi, Mukund P; Patil, Kalyani

2005-04-14

[reaction: see text] Enantioselective radical alkylation of Baylis-Hillman adducts furnished aldol products in good yield and selectivity. The results illustrate that the selectivity in the hydrogen atom transfer is dependent on the size of the ester substituent, with smaller substituents providing better enantioselectivity.

Bioactive alkaloids from marine sponges

Digital Repository Service at National Institute of Oceanography (India)

Singh, K.S.; Majik, M.S.

lines while kuanoniamine C was less potent but showed high selectivity toward the estrogen dependent breast cancer cell line (Kijjoa et. al., 2007). Recently, Davis’s and coworkers, reported two new cytotoxici- ty peridoacridine alkaloids viz... 10 sponge, Trachycladus laevispirulifer. Excitingly, it displayed promising selective cytotoxicity against a panel of human cancer cell lines. 12.3.1. BISINDOLE ALKALOIDS Bis-indole alkaloids, consisting of two indole moieties...

Investigation of free amino acid, total phenolics, antioxidant activity and purine alkaloids to assess the health properties of non-Camellia tea

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Wu Bi

2016-03-01

Full Text Available To find novel functional beverages from folk teas, 33 species of frequently used non-Camellia tea (plants other than Camellia were collected and compared with Camellia tea (green tea, pu-erh tea and black tea for the first time. Data are reported here on the quantities of 20 free amino acids (FAAs and three purine alkaloids (measured by UHPLC, total polyphenols (measured by Folin-Ciocalteu assay, and antioxidant activity (DPPH. The total amounts of FAAs in non-Camellia tea (0.62–18.99 mg/g are generally less than that of Camellia tea (16.55–24.99 mg/g. However, for certain FAAs, the quantities were much higher in some non-Camellia teas, such as γ-aminobutyric acid in teas from Ampelopsis grossedentata, Isodon serra and Hibiscus sabdariffa. Interestingly, theanine was detected in tea from Potentilla fruticosa (1.16±0.81 mg/g. Furthermore, the content of polyphenols in teas from A. grossedentata, Acer tataricum subsp. ginnala are significantly higher than those from Camellia tea; teas from I. serra, Pistacia chinensis and A. tataricum subsp. ginnala have remarkable antioxidant activities similar to the activities from green tea (44.23 μg/mL. Purine alkaloids (caffeine, theobromine and theophylline were not detected in non-Camellia teas. The investigation suggest some non-Camellia teas may be great functional natural products with potential for prevention of chronic diseases and aging, by providing with abundant polyphenols, antioxidants and specific FAAs.

Investigation of free amino acid, total phenolics, antioxidant activity and purine alkaloids to assess the health properties of non-Camellia tea.

Science.gov (United States)

Bi, Wu; He, Chunnian; Ma, Yunyun; Shen, Jie; Zhang, Linghua Harris; Peng, Yong; Xiao, Peigen

2016-03-01

To find novel functional beverages from folk teas, 33 species of frequently used non-Camellia tea (plants other than Camellia) were collected and compared with Camellia tea (green tea, pu-erh tea and black tea) for the first time. Data are reported here on the quantities of 20 free amino acids (FAAs) and three purine alkaloids (measured by UHPLC), total polyphenols (measured by Folin-Ciocalteu assay), and antioxidant activity (DPPH). The total amounts of FAAs in non-Camellia tea (0.62-18.99 mg/g) are generally less than that of Camellia tea (16.55-24.99 mg/g). However, for certain FAAs, the quantities were much higher in some non-Camellia teas, such as γ-aminobutyric acid in teas from Ampelopsis grossedentata, Isodon serra and Hibiscus sabdariffa. Interestingly, theanine was detected in tea from Potentilla fruticosa (1.16±0.81 mg/g). Furthermore, the content of polyphenols in teas from A. grossedentata, Acer tataricum subsp. ginnala are significantly higher than those from Camellia tea; teas from I. serra, Pistacia chinensis and A. tataricum subsp. ginnala have remarkable antioxidant activities similar to the activities from green tea (44.23 μg/mL). Purine alkaloids (caffeine, theobromine and theophylline) were not detected in non-Camellia teas. The investigation suggest some non-Camellia teas may be great functional natural products with potential for prevention of chronic diseases and aging, by providing with abundant polyphenols, antioxidants and specific FAAs.

Sensitive determination of pyrrolizidine alkaloids in Tussilago farfara L. by field-amplified, sample-stacking, sweeping micellar electrokinetic chromatography.

Science.gov (United States)

Cao, Kun; Xu, Yi; Mu, Xiuni; Zhang, Qing; Wang, Renjie; Lv, Junjiang

2016-11-01

Pyrrolizidine alkaloids are the toxic components in Tussilago farfara L. Due to the lack of standard substances for quantitative analysis and traces of pyrrolizidine alkaloids in total alkaloids, the full quality control of Tussilago farfara L has been limited. In this study, we aimed to solve the difficulty of determination of pyrrolizidine alkaloids and identify more components in the total alkaloids. An on-line preconcentration method has been applied to improve determining sensitivity of pyrrolizidine alkaloids in Tussilago farfara L. in which included field-amplified sample stacking and sweeping in micellar electrokinetic capillary chromatography. The main parameters that affected separation and stacking efficiency were investigated in details. Under the optimal conditions, the sensitivity enhancement factors obtained by the developed method for the analytes were from 15- to 12-fold, the limits of detection of senkirkine and senecionine were 2∼5 μg/L. Senkirkine and senecionine have been detected in alkaloids (c) of Tussilago farfara L, along ferulic acid methyl ester and methyl caffeate. The developed method was also applied to the analysis of acid extraction (a) of Tussilago farfara L, and senkirkine could be detected directly. The results indicated that the developed method is feasible for the analysis of pyrrolizidine alkaloids in Tussilago farfara L with good recoveries. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ergot alkaloid transport across ruminant gastric tissues.

Science.gov (United States)

Hill, N S; Thompson, F N; Stuedemann, J A; Rottinghaus, G W; Ju, H J; Dawe, D L; Hiatt, E E

2001-02-01

Ergot alkaloids cause fescue toxicosis when livestock graze endophyte-infected tall fescue. It is generally accepted that ergovaline is the toxic component of endophyte-infected tall fescue, but there is no direct evidence to support this hypothesis. The objective of this study was to examine relative and potential transport of ergoline and ergopeptine alkaloids across isolated gastric tissues in vitro. Sheep ruminal and omasal tissues were surgically removed and placed in parabiotic chambers. Equimolar concentrations of lysergic acid, lysergol, ergonovine, ergotamine, and ergocryptine were added to a Kreb's Ringer phosphate (KRP) solution on the mucosal side of the tissue. Tissue was incubated in near-physiological conditions for 240 min. Samples were taken from KRP on the serosal side of the chambers at times 0, 30, 60, 120, 180, and 240 min and analyzed for ergot alkaloids by competitive ELISA. The serosal KRP remaining after incubation was freeze-dried and the alkaloid species quantified by HPLC. The area of ruminal and omasal tissues was measured and the potential transportable alkaloids calculated by multiplying the moles of transported alkaloids per square centimeter of each tissue type by the surface area of the tissue. Studies were conducted to compare alkaloid transport in reticular, ruminal, and omasal tissues and to determine whether transport was active or passive. Ruminal tissue had greater ergot alkaloid transport potential than omasal tissue (85 vs 60 mmol) because of a larger surface area. The ruminal posterior dorsal sac had the greatest potential for alkaloid transport, but the other ruminal tissues were not different from one another. Alkaloid transport was less among reticular tissues than among ruminal tissues. Transport of alkaloids seemed to be an active process. The alkaloids with greatest transport potential were lysergic acid and lysergol. Ergopeptine alkaloids tended to pass across omasal tissues in greater quantities than across ruminal

Pyrrolizidine alkaloids: occurrence, biology, and chemical synthesis.

Science.gov (United States)

Robertson, Jeremy; Stevens, Kiri

2017-01-04

Covering: 2013 up to the end of 2015This review covers the isolation and structure of new pyrrolizidines; pyrrolizidine biosynthesis; biological activity, including the occurrence of pyrrolizidines as toxic components or contaminants in foods and beverages; and formal and total syntheses of naturally-occurring pyrrolizidine alkaloids and closely related non-natural analogues.

A 1H-NMR-Based Metabonomic Study on the Anti-Depressive Effect of the Total Alkaloid of Corydalis Rhizoma

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Hongwei Wu

2015-05-01

Full Text Available Corydalis Rhizoma, named YuanHu in China, is the dried tuber of Corydalis yanhusuo W.T. Wang which is used in Traditional Chinese Medicine for pain relief and blood activation. Previous pharmacological studies showed that apart from analgesics, the alkaloids from YuanHu may be useful in the therapy of depression by acting on the GABA, dopamine and benzodiazepine receptors. In this study, the antidepressive effect of the total alkaloid of YuanHu (YHTA was investigated in a chronic unpredictable mild stress (CUMS rat model using 1H-NMR-based metabonomics. Plasma metabolic profiles were analyzed and multivariate data analysis was applied to discover the metabolic biomarkers in CUMS rats. Thirteen biomarkers of CUMS-introduced depression were identified, which are myo-inositol, glycerol, glycine, creatine, glutamine, glutamate, β-glucose, α-glucose, acetoacetate, 3-hydroxybutyrate, leucine and unsaturated lipids (L7, L9. Moreover, a metabolic network of the potential biomarkers in plasma perturbed by CUMS was detected. After YHTA treatment, clear separation between the model group and YHTA-treated group was achieved. The levels of all the abnormal metabolites mentioned above showed a tendency of restoration to normal levels. The results demonstrated the therapeutic efficacy of YHTA against depression and suggested that NMR-based metabolomics can provide a simple and easy tool for the evaluation of herbal therapeutics.

Catalytic Enantioselective Alkylation of β-Keto Esters with Xanthydrol in the Presence of Chiral Palladium Complex

Energy Technology Data Exchange (ETDEWEB)

Kim, Kyu Yeon; Kim, Dae Young [Soonchunhyang Univ., Asan (Korea, Republic of)

2016-01-15

Our research interest has been directed toward the development of synthetic methods for the enantioselective construction of stereogenic carbon centers. Recently, we explored the catalytic enantioselective functionalization of active methines in the presence of chiral palladium(II) complexes. In conclusion, we have accomplished the efficient catalytic enantioselective alkylation of β-keto esters 1 with xanthydrol 2 with high yields and excellent enantioselectivity (up to 98% ee). It should be noted that this alkyaltion reaction proceeds well using air- and moisture-stable chiral palladium com- plexes with low loading (1 mol%)

Vancomycin Molecular Interactions: Antibiotic and Enantioselective Mechanisms

Science.gov (United States)

Ward, Timothy J.; Gilmore, Aprile; Ward, Karen; Vowell, Courtney

Medical studies established that vancomycin and other related macrocyclic antibiotics have an enhanced antimicrobial activity when they are associated as dimers. The carbohydrate units attached to the vancomycin basket have an essential role in the dimerization reaction. Covalently synthesized dimers were found active against vancomycin-resistant bacterial strains. A great similarity between antibiotic potential and enantioselectivity was established. A covalent vancomycin dimer was studied in capillary electrophoresis producing excellent chiral separation of dansyl amino acids. Balhimycin is a macrocyclic glycopeptide structurally similar to vancomycin. The small differences are, however, responsible for drastic differences in enantioselectivity in the same experimental conditions. Contributions from studies examining vancomycin's mechanism for antimicrobial activity have substantially aided our understanding of its mechanism in chiral recognition.

[A method for the determination of ergot alkaloids in food].

Science.gov (United States)

Klug, C; Baltes, W; Krönert, W; Weber, R

1988-02-01

A suitable method has been developed for the routine analysis of the ergot alkaloids ergometrine, ergometrinine, ergosine, ergosinine, ergotamine, ergotaminine, ergocornine, ergocorninine, alpha-ergocryptine, alpha-ergocryptinine, beta-ergocryptine, beta-ergocryptinine, ergocristine and ergocristinine in cereal products. The method consists of food extraction, cleaning of the crude extract by a modified form of the Extrelut method, and identification and quantitative determination of the alkaloids by high pressure liquid chromatography (HPLC). The results are confirmed by thin layer chromatography (TLC) and gas-chromatography/mass spectrometry (GC/MS). Market investigations have shown contaminations in ecological as well as in conventional products, with rye products mainly being contaminated. Within the EEC, a maximum value of 0.05% ergot respectively a total alkaloid content of 1 mg/kg in cereals used for food production is prescribed. This value was not exceeded in any of the investigated samples.

Amides and an alkaloid from Portulaca oleracea.

Science.gov (United States)

Kokubun, Tetsuo; Kite, Geoffrey C; Veitch, Nigel C; Simmonds, Monique S J

2012-08-01

A total of 16 phenolic compounds, including one new and five known N-cinnamoyl phenylethylamides, one new pyrrole alkaloid named portulacaldehyde, five phenylpropanoid acids and amides, and derivatives of benzaldehyde and benzoic acid, were isolated and identified from a polar fraction of an extract of Portulaca oleracea. Their structures were determined through spectroscopic analyses.

Enantioselective synthesis of tetrafluorinated ribose and fructose.

Science.gov (United States)

Linclau, Bruno; Boydell, A James; Timofte, Roxana S; Brown, Kylie J; Vinader, Victoria; Weymouth-Wilson, Alexander C

2009-02-21

A perfluoroalkylidene lithium mediated cyclisation approach for the enantioselective synthesis of a tetrafluorinated aldose (ribose) and of a tetrafluorinated ketose (fructose), both in the furanose and in the pyranose form, is described.

Genotoxic effect of alkaloids

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J. A. P. Henriques

1991-01-01

Full Text Available Because of the increase use of alkaloids in general medical practice in recent years, it is of interest to determine genotoxic, mutagenic and recombinogenic response to different groups of alkaloids in prokaryotic and eucaryotic organisms. Reserpine, boldine and chelerythrine did not show genotoxicity response in the SOS-Chromotest whereas skimmianine showed genotixicity in the presence of a metabolic activation mixture. Voacristine isolated fromthe leaves of Ervatamia coronaria shows in vivo cytostatic and mutagenic effects in Saccharomyces cerevisiae hapioids cells. The Rauwolfia alkaloid (reserpine was not able to induce reverse mutation and recombinational mitotic events (crossing-over and gene conversion in yeast diploid strain XS2316.

Effects of Total Alkaloids of Sophora alopecuroides on Biofilm Formation in Staphylococcus epidermidis

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Xue Li

2016-01-01

Full Text Available Staphylococcus epidermidis (S. epidermidis is an opportunistic pathogen with low pathogenicity and a cause of the repeated outbreak of bovine mastitis in veterinary clinical settings. In this report, a biofilm model of S. epidermidis was generated and the minimal inhibitory concentration (MIC and sub-MIC (SMIC on bacterial cultures were assessed for the following agents: total alkaloids of Sophora alopecuroides (TASA, ciprofloxacin (CIP, and erythromycin (ERY. The formation and characteristic parameters of biofilm were analyzed in terms of XTT assay, silver staining, and confocal laser scanning microscope (CLSM. Results showed that a sub-MIC of TASA could inhibit 50% biofilm of bacterial activity, while 250-fold MIC of CIP and ERY MICs only inhibited 50% and 47% of biofilm formation, respectively. All three agents could inhibit the biofilm formation at an early stage, but TASA showed a better inhibitory effect on the late stage of biofilm thickening. A morphological analysis using CLSM further confirmed the destruction of biofilm by these agents. These results thus suggest that TASA has an inhibitory effect on biofilm formation of clinic S. epidermidis, which may be a potential agent warranted for further study on the treatment prevention of infection related to S. epidermidis in veterinary clinic.

Application of Liquid Chromatography/Ion Trap Mass Spectrometry Technique to Determine Ergot Alkaloids in Grain Products.

Science.gov (United States)

Bryła, Marcin; Szymczyk, Krystyna; Jędrzejczak, Renata; Roszko, Marek

2015-03-01

A liquid chromatography/ion trap mass spectrometry-based method to determine six ergot alkaloids and their isomers is presented. The samples were cleaned on neutral alumina-based solid-phase extraction cartridges. The following method parameters were obtained (depending on the analyte and spiking level): method recovery from 63.0 to 104.6%, relative standard deviation below 18%, linear range from 1 to 325 µg/kg, linear correlation coefficient not less than 0.98. The developed analytical procedure was applied to determine the levels of ergot alkaloids in 65 samples of selected rye-based food products (flour - 34 samples, bran - 12 samples, rye - 18 samples, flakes - 1 sample). Measurable levels of alkaloids were found in majority of the analysed samples, particularly in rye flour. Additionally, alkaloids were determined in ergot sclerotia isolated from rye grains. Total content was nearly 0.01% (97.9 mg/kg). However, the alkaloid profile was dominated by ergocristine at 45.6% (44.7 mg/kg), an alkaloid not commonly found in the tested food products. Ergocorninine at 0.2% (0.2 mg/kg) was the least abundant alkaloid.

Alkaloids from Mongolian species Berberis sibirica Pall

International Nuclear Information System (INIS)

Istatkova, R.; Philipov, S.; Tuleva, P.; Amgalan, A.; Samdan, J.; Dangaa, S.

2007-01-01

From the aerial parts of Berberis sibirica Pall. 6 isoquinoline alkaloids of protoberberine, protopine, benzphenanthridine and proaporphine type were isolated. The known alkaloids (-)-tetrahydropseudocoptisine, pseudoprotopine, (+)-chelidonine and (+)-glaziovine are new for the family Berberidaceae. From the roots of B. sibirica 10 isoquinoline alkaloids of protoberberine, benzylisoquinoline, bisbenzylisoquinoline, aporphine-benzylisoquinoline and proaporphine-benzylisoquinoline type were isolated. 1,10-Di-O-methylpakistanine has been reported for the first time as a natural alkaloid. The known alkaloids (-)-isothalidezine and (+)-armepavine have been found for the first time in the family Berberidaceae. All structures were determined by physical and spectral data. (authors)

Pyrrolizidine alkaloid-derived DNA adducts as a common biological biomarker of pyrrolizidine alkaloid-induced tumorigenicity.

Science.gov (United States)

Xia, Qingsu; Zhao, Yuewei; Von Tungeln, Linda S; Doerge, Daniel R; Lin, Ge; Cai, Lining; Fu, Peter P

2013-09-16

Pyrrolizidine alkaloid-containing plants are the most common poisonous plants affecting livestock, wildlife, and humans. The U.S. National Toxicology Program (NTP) classified riddelliine, a tumorigenic pyrrolizidine alkaloid, as "reasonably anticipated to be a human carcinogen" in the NTP 12th Report on Carcinogens in 2011. We previously determined that four DNA adducts were formed in rats dosed with riddelliine. The structures of the four DNA adducts were elucidated as (i) a pair of epimers of 7-hydroxy-9-(deoxyguanosin-N(2)-yl)dehydrosupinidine adducts (termed as DHP-dG-3 and DHP-dG-4) as the predominant adducts; and (ii) a pair of epimers of 7-hydroxy-9-(deoxyadenosin-N(6)-yl)dehydrosupinidine adducts (termed as DHP-dA-3 and DHP-dA-4 adducts). In this study, we selected a nontumorigenic pyrrolizidine alkaloid, platyphylliine, a pyrrolizidine alkaloid N-oxide, riddelliine N-oxide, and nine tumorigenic pyrrolizidine alkaloids (riddelliine, retrorsine, monocrotaline, lycopsamine, retronecine, lasiocarpine, heliotrine, clivorine, and senkirkine) for study in animals. Seven of the nine tumorigenic pyrrolizidine alkaloids, with the exception of lycopsamine and retronecine, are liver carcinogens. At 8-10 weeks of age, female F344 rats were orally gavaged for 3 consecutive days with 4.5 and 24 μmol/kg body weight test article in 0.5 mL of 10% DMSO in water. Twenty-four hours after the last dose, the rats were sacrificed, livers were removed, and liver DNA was isolated for DNA adduct analysis. DHP-dG-3, DHP-dG-4, DHP-dA-3, and DHP-dA-4 adducts were formed in the liver of rats treated with the individual seven hepatocarcinogenic pyrrolizidine alkaloids and riddelliine N-oxide. These DNA adducts were not formed in the liver of rats administered retronecine, the nontumorigenic pyrrolizidine alkaloid, platyphylliine, or vehicle control. These results indicate that this set of DNA adducts, DHP-dG-3, DHP-dG-4, DHP-dA-3, and DHP-dA-4, is a common biological biomarker of

Kinetic investigation on enantioselective hydrolytic resolution of ...

African Journals Online (AJOL)

Kinetic investigation on enantioselective hydrolytic resolution of epichlorohydrin by crude epoxide hydrolase from domestic duck liver. X Ling, D Lu, J Wang, J Chen, L Ding, J Chen, H Chai, P Ouyang ...

Scientific investigation of crude alkaloids from medicinal plants for the management of pain.

Science.gov (United States)

Shoaib, Mohammad; Shah, Syed Wadood Ali; Ali, Niaz; Shah, Ismail; Ullah, Shafi; Ghias, Mehreen; Tahir, Muhammad Nawaz; Gul, Farah; Akhtar, Sohail; Ullah, Abd; Akbar, Wajid; Ullah, Asad

2016-06-13

Tissue damage is associated with pain, which is an alarming sign. Aspirin and morphine have been widely used in recent decades for management of pain. Medicinal herbs have been in use for treatment of different diseases for centuries. Many of these herbs possess analgesic activity with relatively less incidences of adverse effects. The strong positive correlation of alkaloids in medicinal plants for analgesic activity persuades an intention to determine possible analgesic activity of total alkaloids extracted from the selected medicinal plants using animal models to answer its possible mechanisms. Crude alkaloids from selected medicinal plants (Woodfordia fruticosa, Adhatoda vasica, Chenopodium ambrosioides, Vitex negundo, Peganum harmala and Broussonetia papyrifera) were extracted as per reported literature. The test crude alkaloids were screened foracute toxicity study. Writhings induced by acetic acid, tail immersion method and formalin-induced nociception assay procedures were used for possible analgesic effects of the crude alkaloids. Crude alkaloids were safe up to dose of 1250 mg/kg body weight in mice. The alkaloids significantly reduced the abdominal constrictions, and increased the time for paw licking response in both phases with a significant raise in latency time in nociception models (P ≤ 0.05). Moreover, the antinociceptive response was significantly attenuated by pretreatment with naloxone suggesting involvement of the opioid receptors for possible antinociceptive action. Crude alkaloids of Woodfordia fruticosa and Peganum harmala showed prominent analgesic potentials through inhibition of peripheral as well as central nervous system mechanisms. Further work is required for isolation of the pharmacologically active constituents.

Enantioselective 1,3-dipolar cycloadditions of diazoacetates with electron-deficient olefins.

Science.gov (United States)

Sibi, Mukund P; Stanley, Levi M; Soeta, Takahiro

2007-04-12

[reaction: see text] A general strategy for highly enantioselective 1,3-dipolar cycloaddition of diazoesters to beta-substituted, alpha-substituted, and alpha,beta-disubstituted alpha,beta-unsaturated pyrazolidinone imides is described. Cycloadditions utilizing less reactive alpha,beta-disubstituted dipolarophiles require elevated reaction temperatures, but still provide the corresponding pyrazolines with excellent enantioselectivities. Finally, an efficient synthesis of (-)-manzacidin A employing this cycloaddition methodology as a key step is illustrated.

Alkaloids as Cyclooxygenase Inhibitors in Anticancer Drug Discovery.

Science.gov (United States)

Hashmi, Muhammad Ali; Khan, Afsar; Farooq, Umar; Khan, Sehroon

2018-01-01

Cancer is the leading cause of death worldwide and anticancer drug discovery is a very hot area of research at present. There are various factors which control and affect cancer, out of which enzymes like cyclooxygenase-2 (COX-2) play a vital role in the growth of tumor cells. Inhibition of this enzyme is a very useful target for the prevention of various types of cancers. Alkaloids are a diverse group of naturally occurring compounds which have shown great COX-2 inhibitory activity both in vitro and in vivo. In this mini-review, we have discussed different alkaloids with COX-2 inhibitory activities and anticancer potential which may act as leads in modern anticancer drug discovery. Different classes of alkaloids including isoquinoline alkaloids, indole alkaloids, piperidine alkaloids, quinazoline alkaloids, and various miscellaneous alkaloids obtained from natural sources have been discussed in detail in this review. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Enantiomerization and enantioselective bioaccumulation of metalaxyl in Tenebrio molitor larvae.

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Gao, Yongxin; Wang, Huili; Qin, Fang; Xu, Peng; Lv, Xiaotian; Li, Jianzhong; Guo, Baoyuan

2014-02-01

The enantiomerization and enantioselective bioaccumulation of metalaxyl by a single dose of exposure to Tenebrio molitor larvae under laboratory condition were studied by high-performance liquid chromatography tandem mass spectroscopy (HPLC-MS/MS) based on a ChiralcelOD-3R [cellulosetris-tris-(3, 5-dichlorophenyl-carbamate)] column. Exposure of enantiopure R-metalaxyl and S-metalaxyl in Tenebrio molitor larvae exhibited significant enantiomerization, with formation of the R enantiomers from the S enantiomers, and vice versa, which might be attributed to the chiral pesticide catalyzed by a certain enzyme in Tenebrio molitor larvae. Enantiomerization was not observed in wheat bran during the period of 21 d. In addition, bioaccumulation of rac-metalaxyl in Tenebrio molitor larvae was enantioselective with a preferential accumulation of S-metalaxyl. These results showed that enantioselectivity was caused not only by actual degradation and metabolism but also by enantiomerization, which was an important process in the environmental fate and behavior of metalaxyl enantiomers. Copyright © 2013 Wiley Periodicals, Inc.

Total Synthesis of balanol, Part 2

DEFF Research Database (Denmark)

Tanner, David Ackland; Kelly, Nicholas; Tedenborg, Lars

1997-01-01

A convergent enantioselective total synthesis of the natural product (-)-balanol (1) is described. In addition to benzophenone fragment 8, key intermediates are chiral bicyclic aziridine 3 and the corresponding epoxide 4, both of which undergo highly regio- and stereoselective nucleophilic ring...

Quinine-Promoted, Enantioselective Boron-Tethered Diels-Alder Reaction by Anomeric Control of Transition State Conformation.

Science.gov (United States)

Scholl, Katie; Dillashaw, John; Timpy, Evan; Lam, Yu-Hong; DeRatt, Lindsey; Benton, Tyler R; Powell, Jacqueline P; Houk, Kendall N; Morgan, Jeremy B

2018-05-01

Diels-Alder reactions of tethered vinyl-metal species offer the opportunity to fashion highly functionalized diol intermediates for synthesis. We have developed the first enantioselective boron-tethered Diels-Alder reaction using quinine as a chiral promoter. Quinine recovery, enantioselectivity enhancement, and manipulation of the cyclohexene core are also investigated. DFT modeling calculations confirm the role of quinine as a bidentate ligand enhancing reaction rates. The enantioselectivity of the cycloaddition is proposed to originate from a boron-centered anomeric effect.

Phytotoxicity Assessment of Certain Phytochemical Products Containing Pyrrolizidine Alkaloids

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Cristina Șeremet Oana

2013-10-01

Full Text Available Introduction: Tussilago farfara (coltsfoot, Petasites hybridus (common butterbur, Senecio vernalis (eastern groundsel and Symphytum officinale (comfrey are species traditionally used in phytotherapy that besides the therapeutic compounds contain toxic pyrrolizidine alkaloids (PAs. The aim of the paper is to determine the total PAs content and the phytotoxicity of the above species. Material and methods: The quantitative determination of pyrrolizidine alkaloids is based on the stoichiometric reaction of protonated alkaloids with methyl orange. In acidic conditions the dye is released from the complex and its color is assessed spectrophotometrically using a linear regression curve of senecionine as a standard. The phytotoxicity was assessed by Triticum bioassay that studies the effect of the extracts (0.001-5.00%, w/v upon root elongation (inhibitory concentration - IC50 and on the karyokinetic film. Results: The highest amount of total PAs was found in Senecio vernalis (654.8 ± 35.96 μg/g dry plant and the lowest in Petasites hybridus. The lowest IC50 was found for Tussilago farfara followed by Petasites hybridus, Senecio vernalis, and Symphytum officinale. The results were supported by microscopic examination. Conclusions: The results of the spectrophotometric assay are consistent with the ones found in the literature. All extracts inhibited the elongation of the main root of wheat caryopses, however, no correlation between phytotoxicity and the PAs concentration could be emphasized

Pro-toxic dehydropyrrolizidine alkaloids in the traditional Andean herbal medicine “asmachilca”

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Colegate, Steven M.; Boppré, Michael; Monzón, Julio; Betz, Joseph M.

2015-01-01

Ethnopharmacological relevance Asmachilca is a Peruvian medicinal herb preparation ostensibly derived from Eupatorium gayanum Wedd. = Aristeguietia gayana (Wedd.) R.M. King & H. Rob. (Asteraceae: Eupatorieae). Decoctions of the plant have a reported bronchodilation effect that is purported to be useful in the treatment of respiratory allergies, common cold and bronchial asthma. However, its attractiveness to pyrrolizidine alkaloid-pharmacophagous insects indicated a potential for toxicity for human consumers. Aim of the study To determine if commercial asmachilca samples, including fully processed herbal teas, contain potentially toxic 1,2-dehydropyrrolizidine alkaloids. Materials and methods Two brands of “Asmachilca” herbal tea bags and four other commercial samples of botanical materials for preparing asmachilca medicine were extracted and analyzed using HPLC-esi(+)MS and MS/MS for the characteristic retention times and mass spectra of known dehydropyrrolizidine alkaloids. Other suspected dehydropyrrolizidine alkaloids were tentatively identified based on MS/MS profiles and high resolution molecular weight determinations. Further structure elucidation of isolated alkaloids was based on 1D and 2D NMR spectroscopy. Results Asmachilca attracted many species of moths which are known to pharmacophagously gather dehydropyrrolizidine alkaloids. Analysis of 5 of the asmachilca samples revealed the major presence of the dehydropyrrolizidine alkaloid monoesters rinderine and supinine, and their N-oxides. The 6th sample was very similar but did not contain supinine or its N-oxide. Small quantities of other dehydropyrrolizidine alkaloid monoesters, including echinatine and intermedine, were also detected. In addition, two major metabolites, previously undescribed, were isolated and identified as dehydropyrrolizidine alkaloid monoesters with two “head-to-tail” linked viridifloric and/or trachelanthic acids. Estimates of total pyrrolizidine alkaloid and N

Exo selective enantioselective nitrone cycloadditions.

Science.gov (United States)

Sibi, Mukund P; Ma, Zhihua; Jasperse, Craig P

2004-01-28

We have developed a novel method for accessing exo adducts with high enantioselectivity in nitrone cycloadditions to enoates. Pyrazolidinones proved to be effective achiral templates in the cycloadditions, providing exo adducts typically in >15:1 selectivity and 90-98% ee. The use of Lewis acids that form square planar complexes, such as copper triflate, was important for obtaining high exo selectivity.

Enantioselective Analysis in instruments onboard ROSETTA/PHILAE and ExoMars

Science.gov (United States)

Hendrik Bredehöft, Jan; Thiemann, Wolfram; Meierhenrich, Uwe; Goesmann, Fred

It has been suggested a number of times in the past, to look for chirality as a biomarker. So far, for lack of appropriate instrumentation, space missions have never included enantioselective analysis. The distinction between enantiomers is of crucial importance to the question of the origin of the very first (pre)biotic molecules. If molecules detected in situ on another celestial body were found to exhibit a chiral bias, this would mean that at least partial asymmetric synthesis could take place abiotically. If this chiral bias should be found to be near 100For the currently flying ESA mission ROSETTA an enantioselective instrument was built, to try for the first time to detect and separate chiral molecules in situ. This instrument is COSAC, the Cometary Sampling and Acquisition Experiment, an enantioselective GCMS device[1,2], which is included in the lander PHLIAE that will eventually in 2014 land on the nucleus of comet 67P/Churyumov-Gerasimenko. A similar but even more powerful type of enantioselective GC-MS is in preparation for ESA's ExoMars mission. This instrument is part of MOMA, the Mars Organic Molecules Analyser. It has the objective of identifying and quantifying chiral organic molecules in surface and subsurface samples of Mars. Currently ExoMars is scheduled for 2018. The newly developed enantioselective technique utilized by both COSAC and MOMA will be described, including sample acquisition, derivatization, and separation in space-resistant chiral stationary capillary columns with time-of-flight mass spectrometric detection. Results of enantioselective analyses of representative test samples with special emphasis on amino acids[3], the building blocks of protein polymers, will be presented and we will discuss potential results of space missions Rosetta and ExoMars. [1] Thiemann W.H.-P., Meierhenrich U.: ESA Mission ROSETTA Will Probe for Chirality of Cometary Amino Acids. Origins of Life and Evolution of Biospheres 31 (2001), 199-210. [2

Application of Liquid Chromatography/Ion Trap Mass Spectrometry Technique to Determine Ergot Alkaloids in Grain Products

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Krystyna Szymczyk

2015-01-01

Full Text Available A liquid chromatography/ion trap mass spectrometry-based method to determine six ergot alkaloids and their isomers is presented. The samples were cleaned on neutral alumina-based solid-phase extraction cartridges. The following method parameters were obtained (depending on the analyte and spiking level: method recovery from 63.0 to 104.6 %, relative standard deviation below 18 %, linear range from 1 to 325 μg/kg, linear correlation coefficient not less than 0.98. The developed analytical procedure was applied to determine the levels of ergot alkaloids in 65 samples of selected rye-based food products (flour– 34 samples, bran – 12 samples, rye – 18 samples, flakes – 1 sample. Measurable levels of alkaloids were found in majority of the analysed samples, particularly in rye flour. Additionally, alkaloids were determined in ergot sclerotia isolated from rye grains. Total content was nearly 0.01 % (97.9 mg/kg. However, the alkaloid profi le was dominated by ergocristine at 45.6 % (44.7 mg/kg, an alkaloid not commonly found in the tested food products. Ergocorninine at 0.2 % (0.2 mg/kg was the least abundant alkaloid.

ALKALOIDAL COMPOSITION AND TOXICITY STUDIES OF THREE ...

African Journals Online (AJOL)

Mattock's test for unsaturated pyrrolizidine alkaloids (hepatotoxic) revealed that only C. retusa contained these alkaloids amongst the three species. This indicated that this is a potentially toxic specie. The alkaloids of C. retusa were toxic to albino (Wistar) rats. Marked microscopic lesions were found, principally in the liver.

Highly Enantioselective Rhodium-Catalyzed Addition of Arylboroxines to Simple Aryl Ketones: Efficient Synthesis of Escitalopram.

Science.gov (United States)

Huang, Linwei; Zhu, Jinbin; Jiao, Guangjun; Wang, Zheng; Yu, Xingxin; Deng, Wei-Ping; Tang, Wenjun

2016-03-24

Highly enantioselective additions of arylboroxines to simple aryl ketones have been achieved for the first time with a Rh/(R,R,R,R)-WingPhos catalyst, thus providing a range of chiral diaryl alkyl carbinols with excellent ee values and yields. (R,R,R,R)-WingPhos has been proven to be crucial for the high reactivity and enantioselectivity. The method has enabled a new, concise, and enantioselective synthesis of the antidepressant drug escitalopram. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Palladium-Catalyzed Enantioselective C-H Olefination of Diaryl Sulfoxides through Parallel Kinetic Resolution and Desymmetrization.

Science.gov (United States)

Zhu, Yu-Chao; Li, Yan; Zhang, Bo-Chao; Zhang, Feng-Xu; Yang, Yi-Nuo; Wang, Xi-Sheng

2018-03-07

The first example of Pd II -catalyzed enantioselective C-H olefination with non-chiral or racemic sulfoxides as directing groups was developed. A variety of chiral diaryl sulfoxides were synthesized with high enantioselectivity (up to 99 %) through both desymmetrization and parallel kinetic resolution (PKR). This is the first report of Pd II -catalyzed enantioselective C(sp 2 )-H functionalization through PKR, and it represents a novel strategy to construct sulfur chiral centers. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Alkaloids in the pharmaceutical industry: Structure, isolation and application

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Nikolić Milan

2003-01-01

Full Text Available By the end of the 18th and the beginning of the 19th century a new era began in medicine, pharmaceutics and chemistry that was strongly connected with alkaloids and alkaloid drugs. Even before that it was known that certain drugs administered in limited doses were medicines, and toxic if taken in larger doses (opium, coke leaves, belladonna roots, monkshood tubers crocus or hemlock seeds. However, the identification, isolation and structural characterization of the active ingredients of the alkaloid drugs was only possible in the mid 20th century by the use of modern extraction equipment and instrumental methods (NMR, X-ray diffraction and others.In spite of continuing use over a long time, there is still great interest in investigating new drugs, potential raw materials for the pharmaceutical industry, as well as the more detailed investigation and definition of bio-active components and the indication of their activity range, and the partial synthesis of new alkaloid molecules based on natural alkaloids. The scope of these investigations, especially in the field of semi-synthesis is to make better use of the bio-active ingredients of alkaloid drugs, i.e. to improve the pharmacological effect (stronger and prolonged effect of the medicine, decreased toxicity and side effects, or to extend or change the applications. A combined classification of alkaloids was used, based on the chemical structure and origin, i.e. the source of their isolation to study alkaloid structure. For practical reasons, the following classification of alkaloids was used: ergot alkaloids, poppy alkaloids, tropanic alkaloids purine derivative alkaloids, carbon-cyclic alkaloids, and other alkaloids. The second part of this report presents a table of general procedures for alkaloid isolation from plant drugs (extraction by water non-miscible solvents, extraction by water-miscible solvents and extraction by diluted acid solutions. Also, methods for obtaining chelidonine and

Biosynthetic Pathways of Ergot Alkaloids

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Nina Gerhards

2014-12-01

Full Text Available Ergot alkaloids are nitrogen-containing natural products belonging to indole alkaloids. The best known producers are fungi of the phylum Ascomycota, e.g., Claviceps, Epichloë, Penicillium and Aspergillus species. According to their structures, ergot alkaloids can be divided into three groups: clavines, lysergic acid amides and peptides (ergopeptines. All of them share the first biosynthetic steps, which lead to the formation of the tetracyclic ergoline ring system (except the simplest, tricyclic compound: chanoclavine. Different modifications on the ergoline ring by specific enzymes result in an abundance of bioactive natural products, which are used as pharmaceutical drugs or precursors thereof. From the 1950s through to recent years, most of the biosynthetic pathways have been elucidated. Gene clusters from several ergot alkaloid producers have been identified by genome mining and the functions of many of those genes have been demonstrated by knock-out experiments or biochemical investigations of the overproduced enzymes.

Piperidine alkaloids: human and food animal teratogens.

Science.gov (United States)

Green, Benedict T; Lee, Stephen T; Panter, Kip E; Brown, David R

2012-06-01

Piperidine alkaloids are acutely toxic to adult livestock species and produce musculoskeletal deformities in neonatal animals. These teratogenic effects include multiple congenital contracture (MCC) deformities and cleft palate in cattle, pigs, sheep, and goats. Poisonous plants containing teratogenic piperidine alkaloids include poison hemlock (Conium maculatum), lupine (Lupinus spp.), and tobacco (Nicotiana tabacum) [including wild tree tobacco (Nicotiana glauca)]. There is abundant epidemiological evidence in humans that link maternal tobacco use with a high incidence of oral clefting in newborns; this association may be partly attributable to the presence of piperidine alkaloids in tobacco products. In this review, we summarize the evidence for piperidine alkaloids that act as teratogens in livestock, piperidine alkaloid structure-activity relationships and their potential implications for human health. Copyright © 2012 Elsevier Ltd. All rights reserved.

Enantioselective Alkylation of 2-Oxindoles Catalyzed by a Bifunctional Phase-Transfer Catalyst: Synthesis of (-)-Debromoflustramine B.

Science.gov (United States)

Craig, Ryan; Sorrentino, Emiliano; Connon, Stephen J

2018-03-26

A new bifunctional phase-transfer catalyst that employs hydrogen bonding as a control element was developed to promote efficient enantioselective S N 2 reactions for the construction all-carbon quaternary stereocenters in high yield and excellent enantioselectivity (up to 97 % ee) utilizing the alkylation of a malleable oxindole substrate. The utility of the methodology was demonstrated through a concise and highly enantioselective synthesis of (-)-debromoflustramine B. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Four alkaloids from Annona cherimola.

Science.gov (United States)

Chen, C Y; Chang, F R; Pan, W B; Wu, Y C

2001-04-01

Four alkaloids, annocherine A, annocherine B, cherianoine, and romucosine H, along with one known alkaloid, artabonatine B, were isolated from the MeOH extract of the stems of Annona cherimola. Their structures were identified on the basis of both analysis of their spectral data and from chemical evidence.

Studies toward the synthesis of Amaryllidaceae alkaloids from Morita-Baylis-Hillman adducts: a straightforward synthesis of functionalized dihydroisoquinoline-5(6H)-one core

Energy Technology Data Exchange (ETDEWEB)

Lopes, Elizandra C.S.; Coelho, Fernando [Universidade Estadual de Campinas, SP (Brazil). Inst. de Quimica]. E-mail: coelho@iqm.unicamp.br

2007-07-01

We disclose herein our results concerning a study aiming at the synthesis of the highly substituted carbon skeleton of alkaloids isolated from plants of the Amaryllidaceae family. The total synthesis of the functionalized dihydroisoquinoline-5(6H)-one core, which is the bottom part of the structure of alkaloids isolated from this botanic family, is described, using Morita-Baylis-Hillman adducts as substrate. This compound should be a useful and valuable intermediate for the total synthesis of alkaloids isolated from Amaryllidaceae. (author)

Studies toward the synthesis of Amaryllidaceae alkaloids from Morita-Baylis-Hillman adducts: a straightforward synthesis of functionalized dihydroisoquinoline-5(6H)-one core

International Nuclear Information System (INIS)

Lopes, Elizandra C.S.; Coelho, Fernando

2007-01-01

We disclose herein our results concerning a study aiming at the synthesis of the highly substituted carbon skeleton of alkaloids isolated from plants of the Amaryllidaceae family. The total synthesis of the functionalized dihydroisoquinoline-5(6H)-one core, which is the bottom part of the structure of alkaloids isolated from this botanic family, is described, using Morita-Baylis-Hillman adducts as substrate. This compound should be a useful and valuable intermediate for the total synthesis of alkaloids isolated from Amaryllidaceae. (author)

Synthesis and Antimicrobial Characterization of Half-Calycanthaceous Alkaloid Derivatives

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Shaojun Zheng

2016-09-01

Full Text Available A total of 29 novel tetrahydropyrroloindol-based calycanthaceous alkaloid derivatives were synthesized from indole-3-acetonitrile in good yields. The synthesized compounds were evaluated against nine strains of bacteria and a wide range of plant pathogen fungi. Bioassay results revealed that majority of the compounds displayed similar or higher in vitro antimicrobial activities than the positive control. The biological activities also indicated that substituents at R4 and R5 significantly affect the activities. Notably, compound c4 was found to be most active among the tested calycanthaceous analogues and might be a novel potential leading compound for further development as an antifungal agent. The results could pave the way for further design and structural modification of calycanthaceous alkaloids as antimicrobial agents.

Poisonous plants contaminating edible ones and toxic substances in plant foods. Part 3. Pyrrolizidine alkaloids from Heliotropium digynum Forssk. (= H. luteum, Poir.).

Science.gov (United States)

Hammouda, F M; Rizk, A M; Ismail, S I; Atteya, S Z; Ghaleb, H A; Madkour, M K; Pohland, A E; Wood, G

1984-10-01

Investigation of the alkaloidal constituents of Heliotropium digynum resulted in the isolation of four alkaloids viz. heliotrine, europine, lasiocarpine and 7-angelylheliotrine. Moreover, HPLC and GLC showed the probable presence of heliotridine and some other unidentified minor constituents. A summary of the pharmacotoxicity and biological activity of the ethanolic extract, total alkaloids with special reference to heliotrine is presented.

Selective reduction of peptidic ergot alkaloids

Czech Academy of Sciences Publication Activity Database

Cvak, L.; Stuchlík, J.; Schreiberová, M.; Sedmera, Petr; Havlíček, Vladimír; Flieger, Miroslav; Čejka, J.; Kratochvíl, B.; Jegorov, A.

2000-01-01

Roč. 65, - (2000), s. 1762-1776 ISSN 0010-0765 Institutional research plan: CEZ:AV0Z5020903 Keywords : indole alkaloids * ergot alkaloids * ergopeptides Subject RIV: EE - Microbiology, Virology Impact factor: 0.960, year: 2000

Rhynchophylla total alkaloid rescues autophagy, decreases oxidative stress and improves endothelial vasodilation in spontaneous hypertensive rats.

Science.gov (United States)

Li, Chao; Jiang, Feng; Li, Yun-Lun; Jiang, Yue-Hua; Yang, Wen-Qing; Sheng, Jie; Xu, Wen-Juan; Zhu, Qing-Jun

2018-03-01

Autophagy plays an important role in alleviating oxidative stress and stabilizing atherosclerotic plaques. However, the potential role of autophagy in endothelial vasodilation function has rarely been studied. This study aimed to investigate whether rhynchophylla total alkaloid (RTA) has a positive role in enhancing autophagy through decreasing oxidative stress, and improving endothelial vasodilation. In oxidized low-density lipoprotein (ox-LDL)-treated human umbilical vein endothelial cells (HUVECs), RTA (200 mg/L) significantly suppressed ox-LDL-induced oxidative stress through rescuing autophagy, and decreased cell apoptosis. In spontaneous hypertensive rats (SHR), administration of RTA (50 mg·kg -1 ·d -1 , ip, for 6 weeks) improved endothelin-dependent vasodilation of thoracic aorta rings. Furthermore, RTA administration significantly increased the antioxidant capacity and alleviated oxidative stress through enhancing autophagy in SHR. In ox-LDL-treated HUVECs, we found that the promotion of autophagy by RTA resulted in activation of the AMP-activated protein kinase (AMPK) signaling pathway. Our results show that RTA treatment rescues the ox-LDL-induced autophagy impairment in HUVECs and improves endothelium-dependent vasodilation function in SHR.

Enantioselective conjugate addition of diethylzinc to chalcone catalyzed by Co(acac)2 and chiral amino alcohols

NARCIS (Netherlands)

Vries, André H.M. de; Feringa, Bernard

1997-01-01

Co(acac)2 in the presence of chiral ligands has been employed as catalyst for the enantioselective conjugate addition of diethylzinc to chalcone. With chiral amino alcohols derived from (+)-camphor, enantioselectivities up to 83% were achieved.

Alkaloids from Isopyrum thalictroides L.

Science.gov (United States)

Istatkova, Ralitsa; Philipov, Stefan

2004-06-01

Two new aporphine-benzylisoquinoline alkaloids thaliphine and isothaliphine with a new type of ether bridge were isolated from the roots and rhyzomes of Isopyrum thalictroides L. (Ranunculaceae). Their structures were established by physical and spectral analysis. The known alkaloid N-methylglaucine was isolated for the first time from a plant of the family Ranunculaceae.

Survival and development of Heliothis virescens (Lepidoptera: Noctuidae) larvae on isogenic tobacco lines with different levels of alkaloids.

Science.gov (United States)

Jackson, D Michael; Johnson, A W; Stephenson, M G

2002-12-01

Levels of pyridine alkaloids were measured in 18 tobacco, Nicotiana tabacum L., entries from three parental isolines ('NC 95', 'SC 58', and 'Coker 139'), grown at Tifton, GA, Florence, SC, and Oxford, NC, in 1991. Levels of alkaloids in bud leaves (first fully unfolded leaf below the apical leaf bud) were negatively correlated to natural infestation ratings of tobacco budworm larvae, Heliothis virescens (F.), 7 wk after transplanting. For artificially infested bud leaves at Oxford, there was a significant negative correlation between levels of total alkaloids and larval weights after 1 wk of feeding. In 1992, four entries from the 'NC 95' isoline were grown at Oxford, and samples for alkaloid analyses were taken every 2 wk at several leaf positions on each plant. During weeks 4, 8, 12, and 16, second instar tobacco budworms were caged on individual, intact leaves inside perforated plastic bags in the field. The survival and development of tobacco budworm larvae after 1 wk were negatively correlated with levels of alkaloids at the various leaf positions. Larvae survived better and grew faster on the bud leaves of each entry where alkaloid levels were lower than they did on leaves further down the stalk where alkaloid levels were higher. More larvae survived on the lower leaves of the low alkaloid lines than on the lower leaves of the high alkaloid lines. Even moderate increases in pyridine alkaloids had negative effects on tobacco budworm survival and development. Nicotine constituted >97% of the pyridine alkaloids in the 'NC95' isoline each year.

A Submarine Journey: The Pyrrole-Imidazole Alkaloids

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Alessandra Scolaro

2009-11-01

Full Text Available In his most celebrated tale “The Picture of Dorian Gray”, Oscar Wilde stated that “those who go beneath the surface do so at their peril”. This sentence could be a prophetical warning for the practitioner who voluntarily challenges himself with trying to synthesize marine sponge-deriving pyrrole-imidazole alkaloids. This now nearly triple-digit membered community has been growing exponentially in the last 20 years, both in terms of new representatives and topological complexity − from simple, achiral oroidin to the breathtaking 12-ring stylissadines A and B, each possessing 16 stereocenters. While the biosynthesis and the role in the sponge economy of most of these alkaloids still lies in the realm of speculations, significant biological activities for some of them have clearly emerged. This review will account for the progress in achieving the total synthesis of the more biologically enticing members of this class of natural products.

Benzylisoquinoline alkaloid biosynthesis in opium poppy.

Science.gov (United States)

Beaudoin, Guillaume A W; Facchini, Peter J

2014-07-01

Opium poppy (Papaver somniferum) is one of the world's oldest medicinal plants and remains the only commercial source for the narcotic analgesics morphine, codeine and semi-synthetic derivatives such as oxycodone and naltrexone. The plant also produces several other benzylisoquinoline alkaloids with potent pharmacological properties including the vasodilator papaverine, the cough suppressant and potential anticancer drug noscapine and the antimicrobial agent sanguinarine. Opium poppy has served as a model system to investigate the biosynthesis of benzylisoquinoline alkaloids in plants. The application of biochemical and functional genomics has resulted in a recent surge in the discovery of biosynthetic genes involved in the formation of major benzylisoquinoline alkaloids in opium poppy. The availability of extensive biochemical genetic tools and information pertaining to benzylisoquinoline alkaloid metabolism is facilitating the study of a wide range of phenomena including the structural biology of novel catalysts, the genomic organization of biosynthetic genes, the cellular and sub-cellular localization of biosynthetic enzymes and a variety of biotechnological applications. In this review, we highlight recent developments and summarize the frontiers of knowledge regarding the biochemistry, cellular biology and biotechnology of benzylisoquinoline alkaloid biosynthesis in opium poppy.

Study of magnetization switching for MRAM based memory technologies

Science.gov (United States)

Pham, Huy

Amphibian alkaloids are attractive targets for synthesis due to their biological activity. An important class of amphibian alkaloids is the 2,5-disubstituted pyrrolidine-based family of compounds. There are many synthetic approaches for the preparation of the trans-2,5-disubstituted pyrrolidines, but methods for the construction of the cis-2,5-pyrrolidines are limited. Therefore, it was desired to develop an enantioselective approach for the preparation of cis-2,5-disubsituted pyrrolidines. (+)-Tropin-2-one derived from cocaine was used as starting material to exploit the inherent stereochemistry for construction of the cis-pyrrolidine ring. This permitted the unequivocal assignment of the absolute configuration of the target pyrrolidine. The structurally simple pyrrolidine alkaloid, 225H, was selected as a target to develop a general synthetic approach. The enantioselective synthesis of 225H was achieved in nine steps and good overall yield. The search for potent cannabinoid receptor partial agonist ligands as potential marijuana addiction therapeutic agents has led to an investigation of the synthesis of diaryl ether hybrid analogues of BAY 59-3074. A series of 2-(3-alkyl-5-hydroxyphenoxy)-6-(trifluoromethyl)benzonitriles, 3-(2-cyano-3-(trifluoromethyl)phenoxy)phenylalkanoates, and (3-(benzyloxy)phenoxy)-6-(trifluoromethyl)benzonitriles were synthesized and evaluated in vitro for CB1 affinity. The olivetol diaryl ether analogue was the most potent ligand of the alkyl series, but the diaryl ester analogues exhibited modest affinity for CB1 receptors. The most potent compound of the series was the 2-(3-(benzyloxy)phenoxy)-6-(trifluoromethyl)benzonitrile. Keywords. amphibian alkaloids, enantioselective synthesis, pyrrolidine, cannabinoid receptor, marijuana.

Main Alkaloids of Peganum harmala L. and Their Different Effects on Dicot and Monocot Crops

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Chi Zhang

2013-02-01

Full Text Available Alkaloids with allelopathic activity are not as well-known as other allelochemicals. Our study revealed that total alkaloids from seeds of the medicinal plant Peganum harmala L. possessed significant growth inhibitory effect on four treated plants, with dicot plants (lettuce and amaranth being more sensitive than the tested monocot plants (wheat and ryegrass. Further investigation led to the isolation of harmaline and harmine as the main active ingredients in the total alkaloids of P. harmala seeds. Harmaline exerted potent inhibitory effects on seedling growth of treated plants, especially dicots, inhibiting root elongation of lettuce and amaranth by 31% and 47% at a very low concentration (5 µg/mL, whereas harmine exhibited much weaker non-selective inhibitory effect on the plants. Considering the high yield and poor utilization of P. harmala in China, we anticipate that this plant could be exploited as an alternative weed management tool in the future.

Effects of alkaloid extracts of mesquite pod on the products of in vitro rumen fermentation.

Science.gov (United States)

de Jesus Pereira, Taiala Cristina; Pereira, Mara Lúcia Albuquerque; Moreira, Jeruzia Vitória; Azevêdo, José Augusto Gomes; Batista, Ronan; de Paula, Vanderlúcia Fonseca; Oliveira, Brena Santos; de Jesus Dos Santos, Edileusa

2017-02-01

The objective of this study was to evaluate the effects of alkaloid extracts of Prosopis juliflora (Sw.) D.C. pods obtained by two extraction methods as compared with sodium monensin on the gas production kinetic, mitigation of methane, and rumen fermentation products using wheat bran or Tifton 85 hay as substrates, by the semi-automatic in vitro gas production technique. A completely randomized design was adopted, and two natural additives were tested made from mesquite pod (alkaloid extract I and alkaloid extract II) at three levels (3.9, 7.9, and 12 μg), sodium monensin 5 μM (positive control), and no inclusion of additives (negative control). The volume of gases produced by the degradation of the fibrous fraction of wheat bran was influenced by the concentration of the extract I added to the medium, and the amounts of 7.9 and 12 μg were equal to monensin at the lowest value. The degradation rate of the fibrous carbohydrates with additive extract I at 12 μg was lower in relation to monensin. When Tifton 85 hay was utilized, alkaloid extract I provided a shorter colonization time as compared with monensin at the added amounts of 7.9 and 12 μg and higher production of gases from the fibrous fraction but without interfering with the total volume of gases produced during 96 h of fermentation of carbohydrates. In the periods of 12 and 24 h of incubation, utilizing alkaloid extract I, the mean values of methane production with wheat bran and Tifton 85 hay were lower than monensin (p < 0.05) when the respective amounts of 7.9 and 12 μg were added. Alkaloid extract I has similar potential to sodium in reducing production of total gases, methane, and the acetate/propionate ratio.

Guanidine-catalyzed enantioselective desymmetrization of meso-aziridines

KAUST Repository

Zhang, Yan

2011-01-01

An amino-indanol derived chiral guanidine was developed as an efficient Brønsted base catalyst for the desymmetrization of meso-aziridines with both thiols and carbamodithioic acids as nucleophiles, which provided 1,2-difunctionalized ring-opened products in high yields and enantioselectivities. © The Royal Society of Chemistry.

TOXIC PYRROLIZIDINE ALKALOIDS OF ECHIUM AMOENUM FISCH. & MEY.

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MITRA MEHRABANI

2006-06-01

Full Text Available Toxic pyrrolizidine alkaloids are present in some species of Echium (Boraginaceae. In this study petals of Echium amoenum Fisch. & Mey. (Gol-e-Gavzaban as a popular herbal medicine in Iran, were investigated for pyrrolizidine alkaloids (PAs. The alkaloids were separated and purified by preparative TLC and characterized by IR, one and two dimensional 1H and 13C-NMR and Mass spectroscopy. Four toxic alkaloids namely: echimidine I, echimidine isomer II, 7-angeloyl retronecine III and 7-tigloyl retronecine IV were identified.

Enantioselective Epoxide Polymerization Using a Bimetallic Cobalt Catalyst

KAUST Repository

Thomas, Renee M.

2010-11-24

A highly active enantiopure bimetallic cobalt complex was explored for the enantioselective polymerization of a variety of monosubstituted epoxides. The polymerizations were optimized for high rates and stereoselectivity, with s-factors (kfast/kslow) for most epoxides exceeding 50 and some exceeding 300, well above the threshold for preparative utility of enantiopure epoxides and isotactic polyethers. Values for mm triads of the resulting polymers are typically greater than 95%, with some even surpassing 98%. In addition, the use of a racemic catalyst allowed the preparation of isotactic polyethers in quantitative yields. The thermal properties of these isotactic polyethers are presented, with many polymers exhibiting high T m values. This is the first report of the rapid synthesis of a broad range of highly isotactic polyethers via the enantioselective polymerization of racemic epoxides. © 2010 American Chemical Society.

Enantioselective Epoxide Polymerization Using a Bimetallic Cobalt Catalyst

KAUST Repository

Thomas, Renee M.; Widger, Peter C. B.; Ahmed, Syud M.; Jeske, Ryan C.; Hirahata, Wataru; Lobkovsky, Emil B.; Coates, Geoffrey W.

2010-01-01

A highly active enantiopure bimetallic cobalt complex was explored for the enantioselective polymerization of a variety of monosubstituted epoxides. The polymerizations were optimized for high rates and stereoselectivity, with s-factors (kfast/kslow) for most epoxides exceeding 50 and some exceeding 300, well above the threshold for preparative utility of enantiopure epoxides and isotactic polyethers. Values for mm triads of the resulting polymers are typically greater than 95%, with some even surpassing 98%. In addition, the use of a racemic catalyst allowed the preparation of isotactic polyethers in quantitative yields. The thermal properties of these isotactic polyethers are presented, with many polymers exhibiting high T m values. This is the first report of the rapid synthesis of a broad range of highly isotactic polyethers via the enantioselective polymerization of racemic epoxides. © 2010 American Chemical Society.

Enantioselective conjugate addition of diethylzinc to chalcone catalyzed by Co(acac)(2) and chiral amino alcohols

NARCIS (Netherlands)

de Vries, A.H.M.; Feringa, B.L.

1997-01-01

Co(acac)(2) in the presence of chiral ligands has been employed as catalyst for the enantioselective conjugate addition of diethylzinc to chalcone. With chiral amino alcohols derived from (+)-camphor, enantioselectivities up to 83% were achieved. (C) 1997 Elsevier Science Ltd.

Enantioselective Rhodium Enolate Protonations. A New Methodology for the Synthesis of β2-Amino Acids

Science.gov (United States)

Sibi, Mukund P.; Tatamidani, Hiroto; Patil, Kalyani

2008-01-01

Rhodium catalyzed conjugate addition of an aryl boronic acid to α-methylamino acrylates followed by enantioselective protonation of the oxa-π-allylrhodium intermediate provides access to aryl substituted β2-amino acids. The impact of the different variables of the reaction on the levels of enantioselectivity has been assessed. PMID:15957893

Evaluation of reversible interconversion in comprehensive two-dimensional gas chromatography using enantioselective columns in first and second dimensions.

Science.gov (United States)

Kröger, Sabrina; Wong, Yong Foo; Chin, Sung-Tong; Grant, Jacob; Lupton, David; Marriott, Philip J

2015-07-24

The reversible molecular interconversion behaviour of a synthesised oxime (2-phenylpropanaldehyde oxime; (C6H5)CH(CH3)CHN(OH)) was investigated by both, single dimensional gas chromatography (1D GC) and comprehensive two-dimensional gas chromatography (GC×GC). Previous studies on small molecular weight oximes were extended to this larger aromatic oxime (molar mass 149.19gmol(-1)) with interest in the extent of interconversion, enantioselective resolution, and retention time. On a polyethylene glycol (PEG; wax-type) column, a characteristic interconversion zone between two antipodes of E and Z isomers was formed by molecules which have undergone isomerisation on the column (E⇌Z). The extent of interconversion was investigated by varying chromatographic conditions (oven temperature and carrier flow rate) to understand the nature of the behaviour observed. The extent of interconversion was negligible in both enantioselective and methyl-phenylpolysiloxane phase-columns, correlating with the low polarity of the stationary phase. In order to obtain isomerisation along with enantio-resolution, a wax-type and an enantioselective column were coupled in either enantioselective-wax or wax-enantioselective order. The most appropriate column arrangement was selected for study by using a GC×GC experiment with either a wax-phase or phenyl-methylpolysiloxane phase as (2)D column. In addition to evaluation of these fast elution columns, a long narrow-bore enantioselective column (10m) was introduced as (2)D, providing an enantioselective-PEG (coupled-column ensemble: (1)D1+(1)D2)×enantioselective ((2)D) column combination. In this instance, the (1)D1 enantioselective column provides enantiomeric separation of the corresponding enantiomers ((R) and (S)) of (E)- and (Z)-2-phenylpropanaldehyde oxime, followed by E/Z isomerisation in the coupled (1)D2 PEG (reactor) column. The resulting chromatographic interconversion region was modulated and separated into either E/Z isomers

Anticancer and reversing multidrug resistance activities of natural isoquinoline alkaloids and their structure-activity relationship.

Science.gov (United States)

Qing, Zhi-Xing; Huang, Jia-Lu; Yang, Xue-Yi; Liu, Jing-Hong; Cao, Hua-Liang; Xiang, Feng; Cheng, Pi; Zeng, Jian-Guo

2017-09-20

The severe anticancer situation as well as the emergence of multidrug-resistant (MDR) cancer cells has created an urgent need for the development of novel anticancer drugs with different mechanisms of action. A large number of natural alkaloids, such as paclitaxel, vinblastine and camptothecin have already been successfully developed into chemotherapy agents. Following the success of these natural products, in this review, twenty-six types of isoquinoline alkaloid (a total of 379 alkaloids), including benzyltetrahydroisoquinoline, aporphine, oxoaporphine, isooxoaporphine, dimeric aporphine, bisbenzylisoquinoline, tetrahydroprotoberberine, protoberberine, protopine, dihydrobenzophenanthridine, benzophenanthridine, benzophenanthridine dimer, ipecac, simple isoquinoline, pavine, montanine, erythrina, chelidonine, tropoloisoquinoline, azafluoranthene, phthalideisoquinoline, naphthylisoquinoline, lycorine, crinane, narciclasine, and phenanthridone, were summarized based on their cytotoxic and MDR reversing activities against various cancer cells. Additionally, the structure-activity relationships of different types of isoquinoline alkaloid were also discussed. Interestingly, some aporphine, oxoaporphine, isooxoaporphine, bisbenzylisoquinoline, and protoberberine alkaloids display more potent anticancer activities or anti-MDR effects than positive control against the tested cancer cells and are regarded as attractive targets for discovery new anticancer drugs or lead compounds. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Enantioselective rhodium enolate protonations. A new methodology for the synthesis of beta2-amino acids.

Science.gov (United States)

Sibi, Mukund P; Tatamidani, Hiroto; Patil, Kalyani

2005-06-23

[reaction: see text] Rhodium-catalyzed conjugate addition of an aryl boronic acid to alpha-methylamino acrylates followed by enantioselective protonation of the oxa-pi-allylrhodium intermediate provides access to aryl-substituted beta(2)-amino acids. The impact of the different variables of the reaction on the levels of enantioselectivity has been assessed.

Antitrichomonal activity of Peganum harmala alkaloid extract against trichomoniasis in pigeon (Columba livia domestica).

Science.gov (United States)

Tabari, M A; Youssefi, M R; Moghadamnia, A A

2017-06-01

1. This study was designed to evaluate the antitrichomonal effects of P. harmala alkaloid extract against T. gallinae, both in vitro and in vivo, as well as comparing it to that of metronidazole, conventional antitrichomonal medication and harmine and harmaline, the two alkaloids present in P. harmala. 2. T. gallinae were collected by the wet mount method from infected free-living pigeons. The in vitro assay was performed using multi-well plates containing test compounds in final concentrations of 5, 10, 15, 20, 30, 50 or 100 μg/ml. The in vivo assay was done on 60 experimentally infected pigeons dosed with metronidazole at 50 mg/kg body weight (BW) or alkaloids at 25 mg/kg BW. 3. The 24 h minimum inhibitory concentration (MIC) of alkaloid extract was 15 µg/ml while that of metronidazole was 50 µg/ml. Harmine and harmaline revealed 24 h MIC of 30 and 100 µg/ml, respectively. Treatment of infected pigeons with alkaloids led to a full recovery after 3 d but with metronidazole total eradication of trophozoites was not achieved. 4. In conclusion, data of the present study suggested P. harmala is a potent natural anti-trichomonal agent, effective against T. gallinae.

Tropane alkaloids in food: poisoning incidents

NARCIS (Netherlands)

Adamse, P.; Egmond, van H.P.; Noordam, M.Y.; Mulder, P.P.J.; Nijs, de W.C.M.

2014-01-01

A large number of wild and cultured plants produce secondary metabolites that can be toxic to humans and animals. The present study aims to provide insight into the routes of (un)intentional poisonings of humans by tropane alkaloids. Poisonings of humans by tropane alkaloids occur as unintended

Enantioselective radical addition/trapping reactions with alpha,beta-disubstituted unsaturated imides. Synthesis of anti-propionate aldols.

Science.gov (United States)

Sibi, Mukund P; Petrovic, Goran; Zimmerman, Jake

2005-03-02

This manuscript describes a highly diastereo- and enantioselective intermolecular radical addition/hydrogen atom transfer to alpha,beta-disubstituted enoates. Additionally, we show that anti-propionate aldol-like products can be easily prepared from alpha-methyl-beta-acyloxyenoates in good yields and high diastereo- and enantioselectivities.

Pyrrolizidine alkaloids of Senecio sp from Peru

International Nuclear Information System (INIS)

Ruiz Vasquez, Liliana; Reina Artiles, Matias; Gonzalez Coloma, Azucena; Cabrera Perez, Raimundo; Ruiz Mesia, Lastenia

2011-01-01

Six pyrrolizidine alkaloids (PAs) (two saturated macrocyclic, three unsaturated macrocyclic and one unsaturated seco-macrocyclic) were isolated from native Peruvian Senecio species. The structures of these alkaloids were established by a complete NMR spectroscopic analysis, chemical transformations and comparison of their NMR data with those published for similar alkaloids. Three PAs were then tested for antifungal activity against Fusarium moniliforme, F. (Sheldon), F. oxysporum fs. lycopersici (Scheldt) and F. solani (Mart), no significant activity being observed. (author)

Pyrrolizidine alkaloids of Senecio sp from Peru

Energy Technology Data Exchange (ETDEWEB)

Ruiz Vasquez, Liliana; Reina Artiles, Matias [Instituto de Productos Naturales y Agrobiologia, CSIC, Tenerife (Spain); Gonzalez Coloma, Azucena [Instituto de Ciencias Agrarias (ICA), CSIC, Madrid (Spain); Cabrera Perez, Raimundo [Universidad de La Laguna (ULL), Tenerife (Spain). Unidad de Fitopatologia, Facultad de Biologia; Ruiz Mesia, Lastenia [Universidad Nacional de la Amazonia Peruana (LIPNAA-UNAP), AA.HH. Nuevo San Lorenzo, San Juan, Iquitos (Peru). Lab. de Investigacion en Productos Naturales Antiparasitarios de la Amazonia

2011-07-01

Six pyrrolizidine alkaloids (PAs) (two saturated macrocyclic, three unsaturated macrocyclic and one unsaturated seco-macrocyclic) were isolated from native Peruvian Senecio species. The structures of these alkaloids were established by a complete NMR spectroscopic analysis, chemical transformations and comparison of their NMR data with those published for similar alkaloids. Three PAs were then tested for antifungal activity against Fusarium moniliforme, F. (Sheldon), F. oxysporum fs. lycopersici (Scheldt) and F. solani (Mart), no significant activity being observed. (author)

Pyrrolizidine alkaloids of senecio sp from Peru

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Liliana Ruiz Vásquez and Matías Reina Artiles

2011-01-01

Full Text Available Six pyrrolizidine alkaloids (PAs (two saturated macrocyclic, three unsaturated macrocyclic and one unsaturated seco-macrocyclic were isolated from native Peruvian Senecio species. The structures of these alkaloids were established by a complete NMR spectroscopic analysis, chemical transformations and comparison of their NMR data with those published for similar alkaloids. Three PAs were then tested for antifungal activity against Fusarium moniliforme, F. (Sheldon, F. oxysporum fs. lycopersici (Scheldt and F. solani (Mart, no significant activity being observed.

Enantioselective properties of induced lipases from Geotrichum

Czech Academy of Sciences Publication Activity Database

Zarevúcka, Marie; Kejík, Z.; Šaman, David; Wimmer, Zdeněk; Demnerová, K.

2005-01-01

Roč. 37, - (2005), s. 481-486 ISSN 0141-0229 R&D Projects: GA MŠk(CZ) OC D30.001; GA MŠk(CZ) OC D13.10 Institutional research plan: CEZ:AV0Z40550506 Keywords : Geotrichum * lipase * enantioselectivity Subject RIV: CC - Organic Chemistry Impact factor: 1.705, year: 2005

Lanthanide Lewis acid-mediated enantioselective conjugate radical additions.

Science.gov (United States)

Sibi, Mukund P; Manyem, Shankar

2002-08-22

[reaction: see text] Lanthanide triflates along with proline-derived ligands have been found to be efficient catalysts for enantioselective conjugate addition of nucleophilic radicals to enoates. N-Acyl oxazolidinones, when used as achiral additives, gave meaningful enhancements in the ees for the product.

Enantioselective recognition of mandelic acid by a 3,6-dithiophen-2-yl-9H-carbazole-based chiral fluorescent bisboronic acid sensor.

Science.gov (United States)

Wu, Yubo; Guo, Huimin; James, Tony D; Zhao, Jianzhang

2011-07-15

We have prepared chiral fluorescent bisboronic acid sensors with 3,6-dithiophen-2-yl-9H-carbazole as the fluorophore. The thiophene moiety was used to extend the π-conjugation framework of the fluorophore in order to red-shift the fluorescence emission and, at the same time, to enhance the novel process where the fluorophore serves as the electron donor of the photoinduced electron transfer process (d-PET) of the boronic acid sensors; i.e., the background fluorescence of the sensor 1 at acidic pH is weaker compared to that at neutral or basic pH, in stark contrast to the typical a-PET boronic acid sensors (where the fluorophore serves as the electron acceptor of the photoinduced electron transfer process). The benefit of the d-PET boronic acid sensors is that the recognition of the hydroxylic acids can be achieved at acidic pH. We found that the thiophene moiety is an efficient π-conjugation linker and electron donor; as a result, the d-PET contrast ratio of the sensors upon variation of the pH is improved 10-fold when compared to the previously reported d-PET sensors without the thiophene moiety. Enantioselective recognition of tartaric acid was achieved at acid pH, and the enantioselectivity (total response K(D)I(F)(D)/K(L)I(F)(L)) is 3.3. The fluorescence enhancement (I(F)(Sample)/I(F)(Blank)) of sensor 1 upon binding with tartaric acid is 3.5-fold at pH 3.0. With the fluorescent bisboronic acid sensor 1, enantioselective recognition of mandelic acid was achieved for the first time. To the best of our knowledge, this is the first time that the mandelic acid has been enantioselectively recognized using a chiral fluorescent boronic acid sensor. Chiral monoboronic acid sensor 2 and bisboronic acid sensor 3 without the thiophene moiety failed to enantioselectively recognize mandelic acid. Our findings with the thiophene-incorporated boronic acid sensors will be important for the design of d-PET fluorescent sensors for the enantioselective recognition of �

Asymmetric Synthesis of Optically Active Spirocyclic Indoline Scaffolds through an Enantioselective Reduction of Indoles

KAUST Repository

Borrmann, Ruediger

2016-11-30

An enantioselective synthesis of spirocyclic indoline scaffolds was achieved by applying an asymmetric iridium-catalyzed hydrogenation of 3H-indoles. Low catalyst loadings and mild reaction conditions provide a broad range of differently substituted products with excellent yields and enantioselectivities. The developed methodology allows an efficient synthesis of this important spirocyclic structural motif, which is present in numerous biologically active molecules and privileged structures in medicinal chemistry.

Aporphine alkaloids from Ocotea macrophylla (Lauraceae)

International Nuclear Information System (INIS)

Pabon, Ludy Cristina; Cuca, Luis Enrique

2010-01-01

Four aporphine alkaloids from the wood of Ocotea macrophylla (Lauraceae) were isolated and characterized as (S)-3-methoxy-nordomesticine (1), (S)-N-ethoxycarbonyl-3-methoxy-nordomesticine (2), (S)-N-formyl-3-methoxy-nordomesticine (3) and (S)-N-methoxycarbonyl-3-methoxy-nordomesticine (4); alkaloids 2-4 are being report for the first time. The structure the isolated compounds were determined based on their spectral data and by comparison of their spectral data with values described in literature. The alkaloid fraction and compound 1 showed antifungal activity against Fusarium oxysporum f. sp. lycopersici and also compound 1 showed antimicrobial activity towards Staphylococcus aureus, Enterococcus faecalis as well. (author)

Aporphine alkaloids from Ocotea macrophylla (Lauraceae)

Energy Technology Data Exchange (ETDEWEB)

Pabon, Ludy Cristina; Cuca, Luis Enrique, E-mail: lcpabonb@unal.edu.c [Universidad Nacional de Bogota (Colombia). Facultad de Ciencias. Dept. de Quimica

2010-07-01

Four aporphine alkaloids from the wood of Ocotea macrophylla (Lauraceae) were isolated and characterized as (S)-3-methoxy-nordomesticine (1), (S)-N-ethoxycarbonyl-3-methoxy-nordomesticine (2), (S)-N-formyl-3-methoxy-nordomesticine (3) and (S)-N-methoxycarbonyl-3-methoxy-nordomesticine (4); alkaloids 2-4 are being report for the first time. The structure the isolated compounds were determined based on their spectral data and by comparison of their spectral data with values described in literature. The alkaloid fraction and compound 1 showed antifungal activity against Fusarium oxysporum f. sp. lycopersici and also compound 1 showed antimicrobial activity towards Staphylococcus aureus, Enterococcus faecalis as well. (author)

Aporphine alkaloids from Ocotea macrophylla (Lauraceae

Directory of Open Access Journals (Sweden)

Ludy Cristina Pabon

2010-01-01

Full Text Available Four aporphine alkaloids from the wood of Ocotea macrophylla (Lauraceae were isolated and characterized as (S-3-methoxy-nordomesticine (1, (S-N-ethoxycarbonyl-3-methoxy-nordomesticine (2, (S-N-formyl-3-methoxy-nordomesticine (3 and (S-N-methoxycarbonyl-3-methoxy-nordomesticine (4; alkaloids 2-4 are being report for the first time. The structure the isolated compounds were determined based on their spectral data and by comparison of their spectral data with values described in literature. The alkaloid fraction and compound 1 showed antifungal activity against Fusarium oxysporum f. sp. lycopersici and also compound 1 showed antimicrobial activity towards Staphylococcus aureus, Enterococcus faecalis as well.

A New Mn–Salen Micellar Nanoreactor for Enantioselective Epoxidation of Alkenes in Water

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Francesco P. Ballistreri

2018-03-01

Full Text Available A new chiral Mn–salen catalyst, functionalized with a long aliphatic chain and a choline group, able to act as surfactant catalyst for green epoxidation in water, is here described. This catalyst was employed with a commercial surfactant (CTABr leading to a nanoreactor for the enantioselective epoxidation of some selected alkenes in water, using NaClO as oxidant. This is the first example of a nanoreactor for enantioselective epoxidation of non-functionalized alkenes in water.

Genetics, Genomics and Evolution of Ergot Alkaloid Diversity

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Carolyn A. Young

2015-04-01

Full Text Available The ergot alkaloid biosynthesis system has become an excellent model to study evolutionary diversification of specialized (secondary metabolites. This is a very diverse class of alkaloids with various neurotropic activities, produced by fungi in several orders of the phylum Ascomycota, including plant pathogens and protective plant symbionts in the family Clavicipitaceae. Results of comparative genomics and phylogenomic analyses reveal multiple examples of three evolutionary processes that have generated ergot-alkaloid diversity: gene gains, gene losses, and gene sequence changes that have led to altered substrates or product specificities of the enzymes that they encode (neofunctionalization. The chromosome ends appear to be particularly effective engines for gene gains, losses and rearrangements, but not necessarily for neofunctionalization. Changes in gene expression could lead to accumulation of various pathway intermediates and affect levels of different ergot alkaloids. Genetic alterations associated with interspecific hybrids of Epichloë species suggest that such variation is also selectively favored. The huge structural diversity of ergot alkaloids probably represents adaptations to a wide variety of ecological situations by affecting the biological spectra and mechanisms of defense against herbivores, as evidenced by the diverse pharmacological effects of ergot alkaloids used in medicine.

Chiral gold(I vs chiral silver complexes as catalysts for the enantioselective synthesis of the second generation GSK-hepatitis C virus inhibitor

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María Martín-Rodríguez

2011-07-01

Full Text Available The synthesis of a GSK 2nd generation inhibitor of the hepatitis C virus, by enantioselective 1,3-dipolar cycloaddition between a leucine derived iminoester and tert-butyl acrylate, was studied. The comparison between silver(I and gold(I catalysts in this reaction was established by working with chiral phosphoramidites or with chiral BINAP. The best reaction conditions were used for the total synthesis of the hepatitis C virus inhibitor by a four step procedure affording this product in 99% ee and in 63% overall yield. The origin of the enantioselectivity of the chiral gold(I catalyst was justified according to DFT calculations, the stabilizing coulombic interaction between the nitrogen atom of the thiazole moiety and one of the gold atoms being crucial.

Asymmetric NHC-catalyzed aza-Diels-Alder reactions: Highly enantioselective route to α-amino acid derivatives and DFT calculations

KAUST Repository

Yang, Limin; Wang, Fei; Lee, Richmond; Lv, Yunbo; Huang, Kuo-Wei; Zhong, Guofu

2014-01-01

A facile N-heterocyclic carbene catalytic enantioselective aza-Diels-Alder reaction of oxodiazenes with α-chloroaldehydes as dienophile precursors is reported, with excellent enantioselectivity (ee > 99%) and excellent yield (up to 93%). DFT study

Tandem Mass Spectrometry for Structural Identification of Sesquiterpene Alkaloids from the Stems of Dendrobium nobile Using LC-QToF.

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Wang, Yan-Hong; Avula, Bharathi; Abe, Naohito; Wei, Feng; Wang, Mei; Ma, Shuang-Cheng; Ali, Zulfiqar; Elsohly, Mahmoud A; Khan, Ikhlas A

2016-05-01

Dendrobium nobile is one of the fundamental herbs in traditional Chinese medicine. Sesquiterpene alkaloids are the main active components in this plant. Due to weak ultraviolet absorption and low content in D. nobile, these sesquiterpene alkaloids have not been extensively studied using chromatographic methods. Herein, tandem mass spectrometry combined with liquid chromatography separation provides a tool for the identification and characterization of the alkaloids from D. nobile. A total of nine sesquiterpene alkaloids were characterized by ultrahigh-performance liquid chromatography tandem mass spectrometry. These alkaloids can be classified into two subgroups that are represented by dendrobine and nobilonine. Tandem mass spectrometric studies revealed the fragmentation pathways of these two subgroup alkaloids that were used for the identification and characterization of other alkaloids in D. nobile. Characterization of these alkaloids using accurate mass and diagnostic fragments provided a reliable methodology for the analysis of D. nobile by ultrahigh-performance liquid chromatography tandem mass spectrometry. The limit of detection was defined as the signal-to-noise ratio equal to 3 : 1. Limits of detection of dendrobine and nobilonine were less than 30 ng/mL. The developed method was applied for the analysis of various Dendrobium species and related dietary supplements. Alkaloids were identified from D. nobile, but not detected from commercial samples including 13 other Dendrobium species and the 7 dietary supplements. Georg Thieme Verlag KG Stuttgart · New York.

Enantioselective cycloadditions with alpha,beta-disubstituted acrylimides.

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Sibi, Mukund P; Ma, Zhihua; Itoh, Kennosuke; Prabagaran, Narayanasamy; Jasperse, Craig P

2005-06-09

[reaction: see text] The use of N-H imide templates provides a solution to the problem of rotamer control in Lewis acid catalyzed reactions of alpha,beta-disubstituted acryloyl imides. Reactions proceed through the s-cis rotamer and with improved reactivity because A(1,3) strain is avoided. Enantioselective nitrone, nitrile oxide, and Diels-Alder cycloadditions demonstrate the principle.

Enantioselective polymerization of epoxides using biaryl-linked bimetallic cobalt catalysts: A mechanistic study

KAUST Repository

Ahmed, Syud M.

2013-12-18

The enantioselective polymerization of propylene oxide (PO) using biaryl-linked bimetallic salen Co catalysts was investigated experimentally and theoretically. Five key aspects of this catalytic system were examined: (1) the structural features of the catalyst, (2) the regio- and stereoselectivity of the chain-growth step, (3) the probable oxidation and electronic state of Co during the polymerization, (4) the role of the cocatalyst, and (5) the mechanism of monomer enchainment. Several important insights were revealed. First, density functional theory (DFT) calculations provided detailed structural information regarding the regio- and stereoselective chain-growth step. Specifically, the absolute stereochemistry of the binaphthol linker determines the enantiomer preference in the polymerization, and the interaction between the salen ligand and the growing polymer chain is a fundamental aspect of enantioselectivity. Second, a new bimetallic catalyst with a conformationally flexible biphenol linker was synthesized and found to enantioselectively polymerize PO, though with lower enantioselectivity than the binaphthol linked catalysts. Third, DFT calculations revealed that the active form of the catalyst has two active exo anionic ligands (chloride or carboxylate) and an endo polymer alkoxide which can ring-open an adjacent cobalt-coordinated epoxide. Fourth, calculations showed that initiation is favored by an endo chloride ligand, while propagation is favored by the presence of two exo carboxylate ligands. © 2013 American Chemical Society.

Enantioselective polymerization of epoxides using biaryl-linked bimetallic cobalt catalysts: A mechanistic study

KAUST Repository

Ahmed, Syud M.; Poater, Albert; Childers, M. Ian; Widger, Peter C B; Lapointe, Anne M.; Lobkovsky, Emil B.; Coates, Geoffrey W.; Cavallo, Luigi

2013-01-01

The enantioselective polymerization of propylene oxide (PO) using biaryl-linked bimetallic salen Co catalysts was investigated experimentally and theoretically. Five key aspects of this catalytic system were examined: (1) the structural features of the catalyst, (2) the regio- and stereoselectivity of the chain-growth step, (3) the probable oxidation and electronic state of Co during the polymerization, (4) the role of the cocatalyst, and (5) the mechanism of monomer enchainment. Several important insights were revealed. First, density functional theory (DFT) calculations provided detailed structural information regarding the regio- and stereoselective chain-growth step. Specifically, the absolute stereochemistry of the binaphthol linker determines the enantiomer preference in the polymerization, and the interaction between the salen ligand and the growing polymer chain is a fundamental aspect of enantioselectivity. Second, a new bimetallic catalyst with a conformationally flexible biphenol linker was synthesized and found to enantioselectively polymerize PO, though with lower enantioselectivity than the binaphthol linked catalysts. Third, DFT calculations revealed that the active form of the catalyst has two active exo anionic ligands (chloride or carboxylate) and an endo polymer alkoxide which can ring-open an adjacent cobalt-coordinated epoxide. Fourth, calculations showed that initiation is favored by an endo chloride ligand, while propagation is favored by the presence of two exo carboxylate ligands. © 2013 American Chemical Society.

Pyrrolizidine alkaloids from Heliotropium indicum

International Nuclear Information System (INIS)

Souza, Joao Sammy N.; Machado, Luciana L.; Pessoa, Otilia D.L.; Lemos, Telma L.G.; Braz-Filho, Raimundo; Overk, Cassia R.; Ping Yao; Cordell, Geoffrey A.

2005-01-01

Helindicine (1), a new pyrrolizidine alkaloid with unusual structural features, together with the known lycopsamine (2), were isolated from the roots of Heliotropium indicum (Boraginaceae). The structures were established by a combination of 1D and 2D NMR methods (COSY, HMQC, HMBC, and NOESY) and HREIMS. This is the first report of a lactone pyrrolizidine alkaloid in the genus Heliotropium. Compounds 1 and 2 were assayed for antioxidant activity and showed moderate activity. (author)

Pyrrolizidine alkaloids from Heliotropium indicum

Energy Technology Data Exchange (ETDEWEB)

Souza, Joao Sammy N.; Machado, Luciana L.; Pessoa, Otilia D.L.; Lemos, Telma L.G. [Ceara Univ., Fortaleza, CE (Brazil). Dept. de Quimica Organica e Inorganica]. E-mail: tlemos@dqoi.ufc.br; Braz-Filho, Raimundo [Universidade Estadual do Norte Fluminense (UENF), Campos dos Goytacases, RJ (Brazil). Setor de Quimica de Produtos Naturais; Overk, Cassia R.; Ping Yao; Cordell, Geoffrey A. [University of Illinois at Chicago, IL (United States). College of Pharmacy. Dept. of Medicinal Chemistry and Pharmacognosy

2005-11-15

ndicine (1), a new pyrrolizidine alkaloid with unusual structural features, together with the known lycopsamine (2), were isolated from the roots of Heliotropium indicum (Boraginaceae). The structures were established by a combination of 1D and 2D NMR methods (COSY, HMQC, HMBC, and NOESY) and HREIMS. This is the first report of a lactone pyrrolizidine alkaloid in the genus Heliotropium. Compounds 1 and 2 were assayed for antioxidant activity and showed moderate activity. (author)

New pyrrolizidine alkaloids from Heliotropium crassifolium.

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Farsam, H; Yassa, N; Sarkhail, P; Shafiee, A

2000-05-01

Heliotropium crassifolium Boiss, (Boraginaceae) from a population of Ilam, western region of Iran was studied for pyrrolizidine alklaoids (PAs). Four alkaloids have been identified: europine 1, europine N-oxide 2 and a new pyrrolizidine alkaloids ilamine 3 and its N-oxide 4, respectively. Their structures were elucidated by IR, 1H-NMR and EIMS data.

Bioactive alkaloids produced by fungi. I. Updates on alkaloids from the species of the genera Boletus, Fusarium and psilocybe.

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Mahmood, Zafar Alam; Ahmed, Syed Waseemuddin; Azhar, Iqbal; Sualeh, Mohammad; Baig, Mirza Tasawer; Zoha, Sms

2010-07-01

Fungi, in particular, are able in common with the higher plants and bacteria, to produce metabolites, including alkaloids. Alkaloids, along with other metabolites are the most important fungal metabolites from pharmaceutical and industrial point of view. Based on this observation, the authors of this review article have tried to provide an information on the alkaloids produced by the species of genera: Boletus, Fusarium and Psilocybef from 1981-2009. Thus the review would be helpful and provides valuable information for the researchers of the same field.

Influence of Nonpolar Substances on the Extraction Efficiency of Six Alkaloids in Zoagumhwan Investigated by Ultra Performance Liquid Chromatography and Photodiode Array Detection

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Shijing Liu

2012-11-01

Full Text Available A reverse phase ultra performance liquid chromatography and photodiode array (UPLC-PDA detection method was established for the determination of six alkaloids in Zoagumhwan (ZGW, and further for investigating the influence of nonpolar substances on the extraction efficiency of these alkaloids. The method was based on a BEH C18 (50 mm × 2.1 mm, 1.7 μm column and mobile phase of aqueous phosphoric acid and acetonitrile including 0.05% buffer solution under gradient elution. ZGW samples of ZGW I, II, III and IV were obtained and prepared by pre-processing the crude materials of Coptidis rhizoma and Evodiae fructus using four technologies, namely direct water decoction, removal of nonpolar substances in Evodiae fructus by supercritical fluid extraction (SFE, removal of nonpolar substances in ZGW by SFE and removal of nonpolar substances in ZGW by steam distillation. The developed and validated UPLC-PDA method was precise, accurate and sensitive enough based on the facts that the six alkaloids showed good regression (r > 0.9998, the limit of detections and quantifications for six alkaloids were less than 28.8 and 94.5 ng/mL, respectively, and the recovery was in the range of 98.56%–103.24%. The sequence of the total contents of six alkaloids in these samples was ZGW II > ZGW IV > ZGW III > ZGW I. ZGW II, in which nonpolar substances, including essential oils, were firstly removed from Evodiae fructus by SFE, had the highest content of the total alkaloids, indicating that extraction efficiency of the total alkaloids could be remarkably increased after Evodiae fructus being extracted by SFE.

An efficient and target-oriented sample enrichment method for preparative separation of minor alkaloids by pH-zone-refining counter-current chromatography.

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Feng, Rui-Hong; Hou, Jin-Jun; Zhang, Yi-Bei; Pan, Hui-Qin; Yang, Wenzhi; Qi, Peng; Yao, Shuai; Cai, Lu-Ying; Yang, Min; Jiang, Bao-Hong; Liu, Xuan; Wu, Wan-Ying; Guo, De-An

2015-08-28

An efficient and target-oriented sample enrichment method was established to increase the content of the minor alkaloids in crude extract by using the corresponding two-phase solvent system applied in pH-zone-refining counter-current chromatography. The enrichment and separation of seven minor indole alkaloids from Uncaria rhynchophylla (Miq.) Miq. ex Havil(UR) were selected as an example to show the advantage of this method. An optimized two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (3:7:1:9, v/v) was used in this study, where triethylamine (TEA) as the retainer and hydrochloric acid (HCl) as the eluter were added at the equimolar of 10mM. Crude alkaloids of UR dissolved in the corresponding upper phase (containing 10mM TEA) were extracted twice with lower phase (containing 10mM TEA) and lower phase (containing 10mM HCl), respectively, the second lower phase extract was subjected to pH-zone-refining CCC separation after alkalization and desalination. Finally, from 10g of crude alkaloids, 4g of refined alkaloids was obtained and the total content of seven target indole alkaloids was increased from 4.64% to 15.78%. Seven indole alkaloids, including 54mg isocorynoxeine, 21mg corynoxeine, 46mg isorhynchophylline, 35mg rhynchophylline, 65mg hirsutine, 51mg hirsuteine and 27mg geissoschizine methylether were all simultaneously separated from 2.5g of refined alkaloids, with the purity of 86.4%, 97.5%, 90.3%, 92.1%, 98.5%, 92.3%, and 92.8%, respectively. The total content and purities of the seven minor indole alkaloids were tested by HPLC and their chemical structures were elucidated by ESI-HRMS and (1)H NMR. Copyright © 2015 Elsevier B.V. All rights reserved.

Studies of interaction between two alkaloids and double helix DNA

International Nuclear Information System (INIS)

Sun, Yantao; Peng, Tingting; Zhao, Lei; Jiang, Dayu; Cui, Yuncheng

2014-01-01

This article presents the study on the interaction of two alkaloids (matrine and evodiamine) and hs-DNA by absorption, fluorescence, circular dichroism (CD), DNA melting and viscosity experiments. The spectroscopic studies suggested that two alkaloids can bind to DNA through an intercalative mode. The viscosity measurement and thermal denaturation also indicated that two alkaloids can intercalate to DNA. The binding constants (K A ) and the number of binding sites (n) were determined. At the same time, some significant thermodynamic parameters of the binding of the alkaloids to DNA were obtained. Competitive binding studies revealed that alkaloids had an effect on ethidium bromide (EB) bound DNA. In addition, it was also proved that the fluorescence quenching was influenced by ionic strength. - Highlights: • Interaction between two alkaloids and DNA is studied by spectral methods. • The binding constant and the binding sites between two alkaloids and DNA are obtained. • There are a classical intercalative mode between alkaloids and DNA. • The binding of matrine with DNA is weaker than that of evodiamine. • It is important for us to understand the alkaloids–DNA interactions at a molecular level

Enantioselective functionalization of allylic C-H bonds following a strategy of functionalization and diversification.

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Sharma, Ankit; Hartwig, John F

2013-11-27

We report the enantioselective functionalization of allylic C-H bonds in terminal alkenes by a strategy involving the installation of a temporary functional group at the terminal carbon atom by C-H bond functionalization, followed by the catalytic diversification of this intermediate with a broad scope of reagents. The method consists of a one-pot sequence of palladium-catalyzed allylic C-H bond oxidation under neutral conditions to form linear allyl benzoates, followed by iridium-catalyzed allylic substitution. This overall transformation forms a variety of chiral products containing a new C-N, C-O, C-S, or C-C bond at the allylic position in good yield with a high branched-to-linear selectivity and excellent enantioselectivity (ee ≤97%). The broad scope of the overall process results from separating the oxidation and functionalization steps; by doing so, the scope of nucleophile encompasses those sensitive to direct oxidative functionalization. The high enantioselectivity of the overall process is achieved by developing an allylic oxidation that occurs without acid to form the linear isomer with high selectivity. These allylic functionalization processes are amenable to an iterative sequence leading to (1,n)-functionalized products with catalyst-controlled diastereo- and enantioselectivity. The utility of the method in the synthesis of biologically active molecules has been demonstrated.

Pyrrolizidine alkaloids from Heliotropium indicum

OpenAIRE

Souza,João Sammy N.; Machado,Luciana L.; Pessoa,Otília D. L.; Braz-Filho,Raimundo; Overk,Cassia R.; Yao,Ping; Cordell,Geoffrey A.; Lemos,Telma L. G.

2005-01-01

Helindicine (1), a new pyrrolizidine alkaloid with unusual structural features, together with the known lycopsamine (2), were isolated from the roots of Heliotropium indicum (Boraginaceae). The structures were established by a combination of 1D and 2D NMR methods (COSY, HMQC, HMBC, and NOESY) and HREIMS. This is the first report of a lactone pyrrolizidine alkaloid in the genus Heliotropium. Compounds 1 and 2 were assayed for antioxidant activity and showed moderate activity. Um novo alcaló...

Tuning and Switching Enantioselectivity of Asymmetric Carboligation in an Enzyme through Mutational Analysis of a Single Hot Spot.

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Wechsler, Cindy; Meyer, Danilo; Loschonsky, Sabrina; Funk, Lisa-Marie; Neumann, Piotr; Ficner, Ralf; Brodhun, Florian; Müller, Michael; Tittmann, Kai

2015-12-01

Enantioselective bond making and breaking is a hallmark of enzyme action, yet switching the enantioselectivity of the reaction is a difficult undertaking, and typically requires extensive screening of mutant libraries and multiple mutations. Here, we demonstrate that mutational diversification of a single catalytic hot spot in the enzyme pyruvate decarboxylase gives access to both enantiomers of acyloins acetoin and phenylacetylcarbinol, important pharmaceutical precursors, in the case of acetoin even starting from the unselective wild-type protein. Protein crystallography was used to rationalize these findings and to propose a mechanistic model of how enantioselectivity is controlled. In a broader context, our studies highlight the efficiency of mechanism-inspired and structure-guided rational protein design for enhancing and switching enantioselectivity of enzymatic reactions, by systematically exploring the biocatalytic potential of a single hot spot. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Selector/selectand molecular complex for the study of enantiodiscriminative processes

Czech Academy of Sciences Publication Activity Database

Bachechi, F.; Flieger, Miroslav; Sinibaldi, M.

2006-01-01

Roč. 17, - (2006), s. 509-517 ISSN 1040-0400 Institutional research plan: CEZ:AV0Z50200510 Keywords : chiral recognition * enantioselective chromatographic separations * ergot alkaloids Subject RIV: EE - Microbiology, Virology Impact factor: 1.510, year: 2006

L-Threonine-derived novel bifunctional phosphine-sulfonamide catalyst-promoted enantioselective aza-morita-Baylis-Hillman reaction

KAUST Repository

Zhong, Fangrui

2011-03-18

A series of novel bifunctional phosphine-sulfonamide organic catalysts were designed and readily prepared from natural amino acids, and they were utilized to promote enantioselective aza-Morita-Baylis-Hillman (MBH) reactions. l-Threonine-derived phosphine-sulfonamide 9b was found to be the most efficient catalyst, affording the desired aza-MBH adducts in high yields and with excellent enantioselectivities. © 2011 American Chemical Society.

Enantioselective Degradation and Chiral Stability of Metalaxyl-M in Tomato Fruits.

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Jing, Xu; Yao, Guojun; Wang, Peng; Liu, Donghui; Qi, Yanli; Zhou, Zhiqiang

2016-05-01

Metalaxyl is an important chiral acetanilide fungicide, and the activity almost entirely originates from the R-enantiomer. Racemic metalaxyl has been gradually replaced by the enantiopure R-enantiomer (metalaxyl-M). In this study a chiral residue analysis method for metalaxyl and the metabolite metalaxyl acid was set up based on high-performance liquid chromatography tandem mass spectroscopy (HPLC-MS/MS). The enantioselective degradation and chiral stability of metalaxyl-M in tomato fruits in two geographically distinct regions of China (Heilongjiang and Hunan Province) were evaluated and the enantioselectivity of metalaxyl acid was also investigated. Tomato plants grew under field conditions with a one-time spray application of metalaxyl-M wettable powder. It was found that R-metalaxyl was not chirally stable and the inactive S-metalaxyl was detected in tomato fruits. At day 40, S-metalaxyl derived from R-metalaxyl accounted for 32% and 26% of the total amount of metalaxyl, respectively. The metabolites R-metalaxyl acid and S-metalaxyl acid were both observed in tomato, and the ratio of S-metalaxyl acid to the sum of S- and R-metalaxyl acid was 36% and 28% at day 40, respectively. For both metalaxyl and metalaxyl acid, the half-life of the S-enantiomer was longer than the R-enantiomer. The results indicated that the enantiomeric conversion should be considered in the bioactivity evaluation and environmental pollution assessment. Chirality 28:382-386, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

The synthesis of 3H-putrescine and subsequent biosynthesis of 3H-jacobine, a pyrrolizidine alkaloid from Senecio jacobaea

International Nuclear Information System (INIS)

Reed, R.L.; Buhler, D.R.; Oregon State Univ., Corvallis

1988-01-01

A new method was developed for the preparation of tritiated putrescine dihydrochloride ([2,3- 3 H]-1,4-diaminobutane dihydro-chloride) from succinonitrile (1,4-butanedinitrile) and 3 H 2 O, with a radiochemical yield of 16%. Tritiated jacobine and other pyrrolizidine alkaloids were then biosynthesized in Senecio jacobaea using 3 H-putrescine-2HCl as the precursor with a radiochemical yield of 0.9% into total pyrrolizidine alkaloids. Jacobine accounted for 36% of the total. This synthetic method provides a relatively inexpensive source for the preparation of these labelled compounds. (author)

Racemic alkaloids from the fungus Ganoderma cochlear.

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Wang, Xin-Long; Dou, Man; Luo, Qi; Cheng, Li-Zhi; Yan, Yong-Ming; Li, Rong-Tao; Cheng, Yong-Xian

2017-01-01

Seven pairs of new alkaloid enantiomers, ganocochlearines C-I (1, 3-8), and three pairs of known alkaloids were isolated from the fruiting bodies of Ganoderma cochlear. The chemical structures of new compounds were elucidated on the basis of 1D and 2D NMR data. The absolute configurations of compounds 1, 3-10 were assigned by ECD calculations. Biological activities of these isolates against renal fibrosis were accessed in rat normal or diseased renal interstitial fibroblast cells. Importantly, the plausible biosynthetic pathway for this class of alkaloids was originally proposed. Copyright © 2016 Elsevier B.V. All rights reserved.

Hemlock alkaloids from Socrates to poison aloes.

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Reynolds, Tom

2005-06-01

Hemlock (Conium maculatum L. Umbelliferae) has long been known as a poisonous plant. Toxicity is due to a group of piperidine alkaloids of which the representative members are coniine and gamma-coniceine. The latter is the more toxic and is the first formed biosynthetically. Its levels in relation to coniine vary widely according to environmental conditions and to provenance of the plants. Surprisingly, these piperidine alkaloids have turned up in quite unrelated species in the monocotyledons as well as the dicotyledons. Aloes, for instance, important medicinal plants, are not regarded as poisonous although some species are very bitter. Nevertheless a small number of mostly local species contain the alkaloids, especially gamma-coniceine and there have been records of human poisoning. The compounds are recognized by their characteristic mousy smell. Both acute and chronic symptoms have been described. The compounds are neurotoxins and death results from respiratory failure, recalling the effects of curare. Chronic non-lethal ingestion by pregnant livestock leads to foetal malformation. Both acute and chronic toxicity are seen with stock in damp meadows and have been recorded as problems especially in North America. The alkaloids derive biosynthetically from acetate units via the polyketide pathway in contrast to other piperidine alkaloids which derive from lysine.

Alkaloids in the human food chain--natural occurrence and possible adverse effects.

Science.gov (United States)

Koleva, Irina I; van Beek, Teris A; Soffers, Ans E M F; Dusemund, Birgit; Rietjens, Ivonne M C M

2012-01-01

Alkaloid-containing plants are an intrinsic part of the regular Western diet. The present paper summarizes the occurrence of alkaloids in the food chain, their mode of action and possible adverse effects including a safety assessment. Pyrrolizidine alkaloids are a reason for concern because of their bioactivation to reactive alkylating intermediates. Several quinolizidine alkaloids, β-carboline alkaloids, ergot alkaloids and steroid alkaloids are active without bioactivation and mostly act as neurotoxins. Regulatory agencies are aware of the risks and have taken or are considering appropriate regulatory actions for most alkaloids. These vary from setting limits for the presence of a compound in feed, foods and beverages, trying to define safe upper limits, advising on a strategy aiming at restrictions in use, informing the public to be cautious or taking specific plant varieties from the market. For some alkaloids known to be present in the modern food chain, e.g., piperine, nicotine, theobromine, theophylline and tropane alkaloids risks coming from the human food chain are considered to be low if not negligible. Remarkably, for many alkaloids that are known constituents of the modern food chain and of possible concern, tolerable daily intake values have so far not been defined. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of metals on enantioselective toxicity and biotransformation of cis-bifenthrin in zebrafish.

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Yang, Ye; Ji, Dapeng; Huang, Xin; Zhang, Jianyun; Liu, Jing

2017-08-01

Co-occurrence of pyrethroids and metals in watersheds previously has been reported to pose great risk to aquatic species. Pyrethroids are a class of chiral insecticides that have been shown to have enantioselective toxicity and biotransformation. However, the influence of metals on enantioselectivity of pyrethroids has not yet been evaluated. In the present study, the effects of cadmium (Cd), copper (Cu), and lead (Pb) on the enantioselective toxicity and metabolism of cis-bifenthrin (cis-BF) were investigated in zebrafish at environmentally relevant concentrations. The addition of Cd, Cu, or Pb significantly increased the mortality of zebrafish in racemate and R-enantiomer of cis-BF-treated groups. In rac-cis-BF- or 1R-cis-BF-treated groups, the addition of Cd, Cu, or Pb caused a decrease in enantiomeric fraction (EF) and an increased ratio of R-enantiomer residues in zebrafish. In 1S-cis-BF-treated groups, coexposure to Cd led to a lower EF and decreased residue levels of S-enantiomer. In addition, coexposure to the 3 metals resulted in different biodegradation characteristics of each enantiomer accompanied with differential changes in the expression of cytochrome P450 (CYP)1, CYP2, and CYP3 genes, which might be responsible for the enantioselective biodegradation of cis-BF in zebrafish. These results suggest that the influence of coexistent metals should be considered in the ecological risk assessment of chiral pyrethroids in aquatic environments. Environ Toxicol Chem 2017;36:2139-2146. © 2017 SETAC. © 2017 SETAC.

Asymmetric Hydrogenation of Seven-Membered C=N-containing Heterocycles and Rationalization of the Enantioselectivity.

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Balakrishna, Bugga; Bauzá, Antonio; Frontera, Antonio; Vidal-Ferran, Anton

2016-07-18

Iridium(I) complexes with phosphine-phosphite ligands efficiently catalyze the enantioselective hydrogenation of diverse seven-membered C=N-containing heterocyclic compounds (eleven examples; up to 97 % ee). The P-OP ligand L3, which incorporates an ortho-diphenyl substituted octahydrobinol phosphite fragment, provided the highest enantioselectivities in the hydrogenation of most of the heterocyclic compounds studied. The observed stereoselection was rationalized by means of DFT calculations. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chemical Composition and Evaluation of Nicotine, Tobacco Alkaloids, pH and Selected Flavors in e-Cigarette Cartridges and Refill Solutions

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Lisko, Joseph G.; Tran, Hang; Stanfill, Stephen B.; Blount, Benjamin C.; Watson, Clifford H.

2015-01-01

Introduction Electronic cigarette (e-cigarette) use is increasing dramatically in developed countries, but little is known about these rapidly evolving products. This study analyzed and evaluated the chemical composition including nicotine, tobacco alkaloids, pH and flavors in 36 e-liquids brands from four manufacturers. Methods We determined the concentrations of nicotine, alkaloids, and select flavors and measured pH in solutions used in e-cigarettes. E-cigarette products were chosen based upon favorable consumer approval ratings from online review websites. Quantitative analyses were performed using strict quality assurance/quality control (QC) validated methods previously established by our lab for the measurement of nicotine, alkaloids, pH and flavors. Results Three-quarters of the products contained lower measured nicotine levels than the stated label values (6% - 42% by concentration). The pH for e-liquids ranged from 5.1 – 9.1. Minor tobacco alkaloids were found in all samples containing nicotine, and their relative concentrations varied widely among manufacturers. A number of common flavor compounds were analyzed in all e-liquids. Conclusions Free nicotine levels calculated from the measurement of pH correlated with total nicotine content. The direct correlation between the total nicotine concentration and pH suggests that the alkalinity of nicotine drives the pH of e-cigarette solutions. A higher percentage of nicotine exists in the more absorbable free form as total nicotine concentration increases. A number of products contained tobacco alkaloids at concentrations that exceed U.S. Pharmacopeia limits for impurities in nicotine used in pharmaceutical and food products. PMID:25636907

Enantioselective Decarboxylative Alkylation Reactions: Catalyst Development, Substrate Scope, and Mechanistic Studies

Science.gov (United States)

Behenna, Douglas C.; Mohr, Justin T.; Sherden, Nathaniel H.; Marinescu, Smaranda C.; Harned, Andrew M.; Tani, Kousuke; Seto, Masaki; Ma, Sandy; Novák, Zoltán; Krout, Michael R.; McFadden, Ryan M.; Roizen, Jennifer L.; Enquist, John A.; White, David E.; Levine, Samantha R.; Petrova, Krastina V.; Iwashita, Akihiko; Virgil, Scott C.; Stoltz, Brian M.

2012-01-01

α-Quaternary ketones are accessed through novel enantioselective alkylations of allyl and propargyl electrophiles by unstabilized prochiral enolate nucleophiles in the presence of palladium complexes with various phosphinooxazoline (PHOX) ligands. Excellent yields and high enantiomeric excesses are obtained from three classes of enolate precursors: enol carbonates, enol silanes, and racemic β-ketoesters. Each of these substrate classes functions with nearly identical efficiency in terms of yield and enantioselectivity. Catalyst discovery and development, the optimization of reaction conditions, the exploration of reaction scope, and applications in target-directed synthesis are reported. Experimental observations suggest that these alkylation reactions occur through an unusual inner-sphere mechanism involving binding of the prochiral enolate nucleophile directly to the palladium center. PMID:22083969

Enantioselective Decarboxylative Alkylation Reactions: Catalyst Development, Substrate Scope, and Mechanistic Studies

KAUST Repository

Behenna, Douglas C.; Mohr, Justin T.; Sherden, Nathaniel H.; Marinescu, Smaranda C.; Harned, Andrew M.; Tani, Kousuke; Seto, Masaki; Ma, Sandy; Nová k, Zoltá n; Krout, Michael R.; McFadden, Ryan M.; Roizen, Jennifer L.; Enquist, John A.; White, David E.; Levine, Samantha R.; Petrova, Krastina V.; Iwashita, Akihiko; Virgil, Scott C.; Stoltz, Brian M.

2011-01-01

α-Quaternary ketones are accessed through novel enantioselective alkylations of allyl and propargyl electrophiles by unstabilized prochiral enolate nucleophiles in the presence of palladium complexes with various phosphinooxazoline (PHOX) ligands. Excellent yields and high enantiomeric excesses are obtained from three classes of enolate precursor: enol carbonates, enol silanes, and racemic β-ketoesters. Each of these substrate classes functions with nearly identical efficiency in terms of yield and enantioselectivity. Catalyst discovery and development, the optimization of reaction conditions, the exploration of reaction scope, and applications in target-directed synthesis are reported. Experimental observations suggest that these alkylation reactions occur through an unusual inner-sphere mechanism involving binding of the prochiral enolate nucleophile directly to the palladium center.

Enantioselective Decarboxylative Alkylation Reactions: Catalyst Development, Substrate Scope, and Mechanistic Studies

KAUST Repository

Behenna, Douglas C.

2011-11-14

α-Quaternary ketones are accessed through novel enantioselective alkylations of allyl and propargyl electrophiles by unstabilized prochiral enolate nucleophiles in the presence of palladium complexes with various phosphinooxazoline (PHOX) ligands. Excellent yields and high enantiomeric excesses are obtained from three classes of enolate precursor: enol carbonates, enol silanes, and racemic β-ketoesters. Each of these substrate classes functions with nearly identical efficiency in terms of yield and enantioselectivity. Catalyst discovery and development, the optimization of reaction conditions, the exploration of reaction scope, and applications in target-directed synthesis are reported. Experimental observations suggest that these alkylation reactions occur through an unusual inner-sphere mechanism involving binding of the prochiral enolate nucleophile directly to the palladium center.

Cytotoxicity and accumulation of ergot alkaloids in human primary cells.

Science.gov (United States)

Mulac, Dennis; Humpf, Hans-Ulrich

2011-04-11

Ergot alkaloids are secondary metabolites produced by fungi of the species Claviceps. Toxic effects after consumption of contaminated grains are described since mediaeval times. Of the more than 40 known ergot alkaloids six are found predominantly. These are ergotamine, ergocornine, ergocryptine, ergocristine, ergosine and ergometrine, along with their corresponding isomeric forms (-inine-forms). Toxic effects are known to be induced by an interaction of the ergot alkaloids as neurotransmitters, like dopamine or serotonin. Nevertheless data concerning cytotoxic effects are missing and therefore a screening of the six main ergot alkaloids was performed in human primary cells in order to evaluate the toxic potential. As it is well known that ergot alkaloids isomerize easily the stability was tested in the cell medium. Based on these results factors were calculated to correct the used concentration values to the biologically active lysergic (-ine) form. These factors range from 1.4 for the most stable compound ergometrine to 5.0 for the most unstable ergot alkaloid ergocristine. With these factors, reflecting the instability, several controverse literature data concerning the toxicity could be explained. To evaluate the cytotoxic effects of ergot alkaloids, human cells in primary culture were used. These cells remain unchanged in contrast to cell lines and the data allow a better comparison to the in vivo situation than using immortalized cell lines. To characterize the effects on primary cells, renal proximal tubule epithelial cells (RPTEC) and normal human astrocytes (NHA) were used. The parameters necrosis (LDH-release) and apoptosis (caspase-3-activation, DNA condensation and fragmentation) were distinguished. The results show that depending on the individual structure of the peptide ergot alkaloids the toxic properties change. While ergometrine as a lysergic acid amide did not show any effect, the peptide ergot alkaloids revealed a different toxic potential. Of

Toxicosis by Plant Alkaloids in Humans and Animals in Colombia

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Gonzalo J. Diaz

2015-12-01

Full Text Available Due to its tropical location, chains of mountains, inter-Andean valleys, Amazon basin area, eastern plains and shores on both the Atlantic and Pacific Oceans, Colombia has many ecosystems and the second largest plant biodiversity in the world. Many plant species, both native and naturalized, are currently recognized as toxic for both animals and humans, and some of them are known to cause their toxic effects due to their alkaloid content. Among these, there are plants containing the hepatotoxic pyrrolizidine alkaloids, neurotoxins such as the indolizidine alkaloid swainsonine and the piperidine alkaloids coniine and γ-coniceine and tropane alkaloids. Unfortunately, the research in toxic plants in Colombia is not nearly proportional to its plant biodiversity and the scientific information available is only very scarce. The present review aims at summarizing the scarce information about plant alkaloid toxicosis in animals and humans in Colombia.

Toxicosis by Plant Alkaloids in Humans and Animals in Colombia

Science.gov (United States)

Diaz, Gonzalo J.

2015-01-01

Due to its tropical location, chains of mountains, inter-Andean valleys, Amazon basin area, eastern plains and shores on both the Atlantic and Pacific Oceans, Colombia has many ecosystems and the second largest plant biodiversity in the world. Many plant species, both native and naturalized, are currently recognized as toxic for both animals and humans, and some of them are known to cause their toxic effects due to their alkaloid content. Among these, there are plants containing the hepatotoxic pyrrolizidine alkaloids, neurotoxins such as the indolizidine alkaloid swainsonine and the piperidine alkaloids coniine and γ-coniceine and tropane alkaloids. Unfortunately, the research in toxic plants in Colombia is not nearly proportional to its plant biodiversity and the scientific information available is only very scarce. The present review aims at summarizing the scarce information about plant alkaloid toxicosis in animals and humans in Colombia. PMID:26690479

Enantioselective [3+3] atroposelective annulation catalyzed by N-heterocyclic carbenes

KAUST Repository

Zhao, Changgui

2018-02-05

Axially chiral molecules are among the most valuable substrates in organic synthesis. They are typically used as chiral ligands or catalysts in asymmetric reactions. Recent progress for the construction of these chiral molecules is mainly focused on the transition-metal-catalyzed transformations. Here, we report the enantioselective NHC-catalyzed (NHC: N-heterocyclic carbenes) atroposelective annulation of cyclic 1,3-diones with ynals. In the presence of NHC precatalyst, base, Lewis acid and oxidant, a catalytic C–C bond formation occurs, providing axially chiral α-pyrone−aryls in moderate to good yields and with high enantioselectivities. Control experiments indicated that alkynyl acyl azoliums, acting as active intermediates, are employed to atroposelectively assemble chiral biaryls and such a methodology may be creatively applied to other useful NHC-catalyzed asymmetric transformations.

Analysis, separation, and bioassay of pyrrolizidine alkaloids from comfrey (Symphytum officinale).

Science.gov (United States)

Couet, C E; Crews, C; Hanley, A B

1996-01-01

Pyrrolizidine alkaloids have been linked to liver and lung cancers and a range of other deleterious effects. As with many natural toxicants, major problems arise in determining the effects of the different members of the class and the importance of various forms of ingestion. In this study we have investigated the levels of pyrrolizidine alkaloids in comfrey (Symphytum officinale), determined the levels in different parts of the plant and in herbal remedies, separated the alkaloids into two main groups--the principal parent alkaloids and the corresponding N-oxides--and, finally, carried out a simple bioassay based upon the mutagenic capability of the separated compounds in a human cell line. We conclude that the part of the plant ingested is important in terms of alkaloid challenge and that the effect of two of the major groups of alkaloids individually is different from that of alkaloids in the whole plant extract.

Initial Studies on Alkaloids from Lombok Medicinal Plants

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John B. Bremner

2001-01-01

Full Text Available Initial investigation of medicinal plants from Lombok has resulted in the collection of 100 plant species predicted to have antimicrobial, including antimalarial, properties according to local medicinal uses. These plants represent 49 families and 80 genera; 23% of the plants tested positively for alkaloids. Among the plants testing positive, five have been selected for further investigation involving structure elucidation and antimicrobial testing on the extracted alkaloids. Initial work on structural elucidation of some of the alkaloids is reported briefly.

Enantioselective Construction of 3-Hydroxypiperidine Scaffolds by Sequential Action of Light and Rhodium upon N-Allylglyoxylamides.

Science.gov (United States)

Ishida, Naoki; Nečas, David; Masuda, Yusuke; Murakami, Masahiro

2015-06-15

3-Hydroxypiperidine scaffolds were enantioselectively constructed in an atom-economical way by sequential action of light and rhodium upon N-allylglyoxylamides. In a formal sense, the allylic C-H bond was selectively cleaved and enantioselectively added across the ketonic carbonyl group with migration of the double bond (carbonyl-ene-type reaction). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Enantioselective biotransformations of nitriles in organic synthesis.

Science.gov (United States)

Wang, Mei-Xiang

2015-03-17

The hydration and hydrolysis of nitriles are valuable synthetic methods used to prepare carboxamides and carboxylic acids. However, chemical hydration and hydrolysis of nitriles involve harsh reaction conditions, have low selectivity, and generate large amounts of waste. Therefore, researchers have confined the scope of these reactions to simple nitrile substrates. However, biological transformations of nitriles are highly efficient, chemoselective, and environmentally benign, which has led synthetic organic chemists and biotechologists to study these reactions in detail over the last two decades. In nature, biological systems degrade nitriles via two distinct pathways: nitrilases catalyze the direct hydrolysis of nitriles to afford carboxylic acids with release of ammonia, and nitrile hydratases catalyze the conversion of nitriles into carboxamides, which then furnish carboxylic acids via hydrolysis in the presence of amidases. Researchers have subsequently developed biocatalytic methods into useful industrial processes for the manufacture of commodity chemicals, including acrylamide. Since the late 1990s, research by my group and others has led to enormous progress in the understanding and application of enantioselective biotransformations of nitriles in organic synthesis. In this Account, I summarize the important advances in enantioselective biotransformations of nitriles and amides, with a primary focus on research from my laboratory. I describe microbial whole-cell-catalyzed kinetic resolution of various functionalized nitriles, amino- and hydroxynitriles, and nitriles that contain small rings and the desymmetrization of prochiral and meso dinitriles and diamides. I also demonstrate how we can apply the biocatalytic protocol to synthesize natural products and bioactive compounds. These nitrile biotransformations offer an attractive and unique protocol for the enantioselective synthesis of polyfunctionalized organic compounds that are not readily obtainable by

Cyclic aldimines as superior electrophiles for Cu-catalyzed decarboxylative Mannich reaction of β-ketoacids with a broad scope and high enantioselectivity.

Science.gov (United States)

Zhang, Heng-Xia; Nie, Jing; Cai, Hua; Ma, Jun-An

2014-05-02

A novel Cu-catalyzed enantioselective decarboxylative Mannich reaction of cyclic aldimines with β-ketoacids is described. The cyclic structure of these aldimines, in which the C═N bond is constrained in the Z geometry, appears to be important, allowing Mannich condensation to proceed in high yields with excellent enantioselectivities. A chiral chroman-4-amine was synthesized from the decarboxylative Mannich product in several steps without loss of enantioselectivity.

Biogenetically inspired synthesis and skeletal diversification of indole alkaloids.

Science.gov (United States)

Mizoguchi, Haruki; Oikawa, Hideaki; Oguri, Hiroki

2014-01-01

To access architecturally complex natural products, chemists usually devise a customized synthetic strategy for constructing a single target skeleton. In contrast, biosynthetic assembly lines often employ divergent intramolecular cyclizations of a polyunsaturated common intermediate to produce diverse arrays of scaffolds. With the aim of integrating such biogenetic strategies, we show the development of an artificial divergent assembly line generating unprecedented numbers of scaffold variations of terpenoid indole alkaloids. This approach not only allows practical access to multipotent intermediates, but also enables systematic diversification of skeletal, stereochemical and functional group properties without structural simplification of naturally occurring alkaloids. Three distinct modes of [4+2] cyclizations and two types of redox-mediated annulations provided divergent access to five skeletally distinct scaffolds involving iboga-, aspidosperma-, andranginine- and ngouniensine-type skeletons and a non-natural variant within six to nine steps from tryptamine. The efficiency of our approach was demonstrated by successful total syntheses of (±)-vincadifformine, (±)-andranginine and (-)-catharanthine.

An integrated strategy for the systematic characterization and discovery of new indole alkaloids from Uncaria rhynchophylla by UHPLC/DAD/LTQ-Orbitrap-MS.

Science.gov (United States)

Pan, Huiqin; Yang, Wenzhi; Zhang, Yibei; Yang, Min; Feng, Ruihong; Wu, Wanying; Guo, Dean

2015-08-01

The exploration of new chemical entities from herbal medicines may provide candidates for the in silico screening of drug leads. However, this significant work is hindered by the presence of multiple classes of plant metabolites and many re-discovered structures. This study presents an integrated strategy that uses ultrahigh-performance liquid chromatography/linear ion-trap quadrupole/Orbitrap mass spectrometry (UHPLC/LTQ-Orbitrap-MS) coupled with in-house library data for the systematic characterization and discovery of new potentially bioactive molecules. Exploration of the indole alkaloids from Uncaria rhynchophylla (UR) is presented as a model study. Initially, the primary characterization of alkaloids was achieved using mass defect filtering and neutral loss filtering. Subsequently, phytochemical isolation obtained 14 alkaloid compounds as reference standards, including a new one identified as 16,17-dihydro-O-demethylhirsuteine by NMR analyses. The direct-infusion fragmentation behaviors of these isolated alkaloids were studied to provide diagnostic structural information facilitating the rapid differentiation and characterization of four different alkaloid subtypes. Ultimately, after combining the experimental results with a survey of an in-house library containing 129 alkaloids isolated from the Uncaria genus, a total of 92 alkaloids (60 free alkaloids and 32 alkaloid O-glycosides) were identified or tentatively characterized, 56 of which are potential new alkaloids for the Uncaria genus. Hydroxylation on ring A, broad variations in the C-15 side chain, new N-oxides, and numerous O-glycosides, represent the novel features of the newly discovered indole alkaloid structures. These results greatly expand our knowledge of UR chemistry and are useful for the computational screening of potentially bioactive molecules from indole alkaloids. Graphical Abstract A four-step integrated strategy for the systematic characterization and efficient discovery of new indole

Enantioselective degradation and enantiomerization of indoxacarb in soil.

Science.gov (United States)

Sun, Dali; Pang, Junxiao; Qiu, Jing; Li, Li; Liu, Chenglan; Jiao, Bining

2013-11-27

In this study, the enantioselective degradation and enantiomerizaton of indoxacarb were investigated in two soils under nonsterilized and sterilized conditions using a chiral OD-RH column on a reversed-phase HPLC. Under nonsterilized conditions, the degradation of indoxacarb in two soils was enantioselective. In acidic soil, the half-lives of R-(-)- and S-(+)-indoxacarb were 10.43 and 14.00 days, respectively. Acidic soil was preferential to the degradation of R-(-)-indoxacarb. In alkaline soil, the half-lives of R-(-)- and S-(+)-indoxacarb were 12.14 and 4.88 days, respectively. S-(+)-Indoxacarb was preferentially degraded. Under sterilized conditions, approximately 5-10% of the initial concentration degraded after 75 days of incubation in acidic soil, whereas in alkaline soil, approximately half of the initial concentration degraded due to chemical hydrolysis under alkaline conditions. Enantiomerization was also discovered in acidic and alkaline soils. The results showed that mutual transformation existed between two enantiomers and that S-(+)-indoxacarb had a significantly higher inversion rate to R-(-)-indoxacarb than its antipode.

Effect of processing on the alkaloids in Aconitum tubers by HPLC-TOF/MS

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Min Liu

2017-06-01

Full Text Available According to the Chinese Pharmacopoeia 2015, only processed Aconitum tubers can be clinically applied, and the effect of processing is unclear. This research aimed to explore the effect of processing on cardiac efficacy of alkaloids in Aconitum tubers. First, the chemical ingredients in unprocessed and processed Aconitum tubers were identified and compared by using high performance liquid chromatography time-of-flight mass spectrometry (HPLC-TOF/MS and multivariate pattern recognition methods. Then the representative alkaloids in Aconitum tubers, aconitine, benzoylaconine, and aconine, which belong to diester-diterpenoid alkaloids, monoester-diterpenoid alkaloids, and amine-diterpenoid alkaloids, respectively, were selected for further validation of attenuated mechanism. Subsequent pharmacological experiments with aconitine, benzoylaconine, and aconine in SD rats were used for validate the effect of processing on cardiac functions. After processing the Aconitum tubers, it was found that the contents of diester-diterpenoid alkaloids were reduced, and those of monoester-diterpenoid alkaloids and amine-diterpenoid alkaloids were increased, suggesting that diester-diterpenoid alkaloids were transformed into monoester-diterpenoid alkaloids and amine-diterpenoid alkaloids. Through further decocting the aconitine in boiling water, it was confirmed that the three alkaloids could be progressively transformed. Pharmacological experiments with aconitine, benzoylaconine, and aconine in SD rats showed that aconitine at a dose of 0.01 mg/kg and aconine at a dose of 10 mg/kg enhanced the cardiac function, while benzoylaconine at a dose of 2 mg/kg weakened the cardiac function. The effect of processing is attributed to the transformation of the most toxic diester-diterpenoid alkaloids into less toxic monoester-diterpenoid alkaloids and amine-diterpenoid alkaloids.

Catalytic asymmetric synthesis of the alkaloid (+)-myrtine

NARCIS (Netherlands)

Pizzuti, Maria Gabriefla; Minnaard, Adriaan J.; Feringa, Ben L.

2008-01-01

A new protocol for the asymmetric synthesis of trans-2,6-disubstituted-4-piperidones has been developed using a catalytic enantioselective conjugate addition reaction in combination with a diastereoselective lithiation-substitution sequence; an efficient synthesis of (+)-myrtine has been achieved

Chiral Nickel(II) Complex Catalyzed Enantioselective Doyle-Kirmse Reaction of α-Diazo Pyrazoleamides.

Science.gov (United States)

Lin, Xiaobin; Tang, Yu; Yang, Wei; Tan, Fei; Lin, Lili; Liu, Xiaohua; Feng, Xiaoming

2018-03-07

Although high enantioselectivity of [2,3]-sigmatropic rearrangement of sulfonium ylides (Doyle-Kirmse reaction) has proven surprisingly elusive using classic chiral Rh(II) and Cu(I) catalysts, in principle it is due to the difficulty in fine discrimination of the heterotopic lone pairs of sulfur and chirality inversion at sulfur of sulfonium ylides. Here, we show that the synergistic merger of new α-diazo pyrazoleamides and a chiral N, N'-dioxide-nickel(II) complex catalyst enables a highly enantioselective Doyle-Kirmse reaction. The pyrazoleamide substituent serves as both an activating and a directing group for the ready formation of a metal-carbene- and Lewis-acid-bonded ylide intermediate in the assistance of a dual-tasking nickel(II) complex. An alternative chiral Lewis-acid-bonded ylide pathway greatly improves the product enantiopurity even for the reaction of a symmetric diallylsulfane. The majority of transformations over a series of aryl- or vinyl-substituted α-diazo pyrazoleamindes and sulfides proceed rapidly (within 5-20 min in most cases) with excellent results (up to 99% yield and 96% ee), providing a breakthrough in enantioselective Doyle-Kirmse reaction.

Kinetic mechanism and enantioselectivity of halohydrin dehalogenase from Agrobacterium radiobacter

NARCIS (Netherlands)

Tang, Lixia; Lutje Spelberg, Jeffrey H.; Fraaije, Marco W.; Janssen, DB

2003-01-01

Halohydrin dehalogenase (HheC) from Agrobacterium radiobacter AD1 catalyzes the reversible intramolecular nucleophilic displacement of a halogen by a hydroxyl group in vicinal haloalcohols, producing the corresponding epoxides. The enzyme displays high enantioselectivity toward some aromatic

New extraction technique for alkaloids

Directory of Open Access Journals (Sweden)

Djilani Abdelouaheb

2006-01-01

Full Text Available A method of extraction of natural products has been developed. Compared with existing methods, the new technique is rapid, more efficient and consumes less solvent. Extraction of alkaloids from natural products such as Hyoscyamus muticus, Datura stramonium and Ruta graveolens consists of the use of a sonicated solution containing a surfactant as extracting agent. The alkaloids are precipitated by Mayer reagent, dissolved in an alkaline solution, and then extracted with chloroform. This article compares the results obtained with other methods showing clearly the advantages of the new method.

Enantioselective conjugate radical addition to alpha'-hydroxy enones.

Science.gov (United States)

Lee, Sunggi; Lim, Chae Jo; Kim, Sunggak; Subramaniam, Rajesh; Zimmerman, Jake; Sibi, Mukund P

2006-09-14

Enantioselective conjugate radical addition to alpha'-hydroxy alpha,beta-unsaturated ketones, compounds containing bidentate donors, has been investigated. It has been found that radical additions to alpha'-hydroxy alpha,beta-unsaturated ketones in the presence of Mg(NTf2)2 and bisoxazoline ligand 5a proceeded cleanly, yielding the addition products in high chemical yields and good enantiomeric excesses.

Diastereoselective and enantioselective reduction of tetralin-1,4-dione

Directory of Open Access Journals (Sweden)

2008-10-01

Full Text Available BackgroundThe chemistry of tetralin-1,4-dione, the stable tautomer of 1,4-dihydroxynaphthalene, has not been explored previously. It is readily accessible and offers interesting opportunities for synthesis.ResultsThe title reactions were explored. L-Selectride reduced the diketone to give preferentially the cis-diol (d.r. 84 : 16. Red-Al gave preferentially the trans-diol (d.r. 13 : 87. NaBH4, LiAlH4, and BH3 gave lower diastereoselectivities (yields: 76–98%. Fractional crystallization allowed isolation of the cis-diol and the trans-diol (55% and 66% yield, respectively. Borane was used to cleanly give the mono-reduction product. Highly enantioselective CBS reductions afforded the trans-diol (72% yield, 99% ee and the mono-reduction product (81%, 95% ee.ConclusionDiastereoselective and enantioselective reductions of the unexplored tetralin-1,4-dione provides a very convenient entry into a number of synthetically highly attractive 1,4-tetralindiols and 4-hydroxy-1-tetralone.

Diastereoselective and enantioselective reduction of tetralin-1,4-dione.

Science.gov (United States)

Kündig, E Peter; Enriquez-Garcia, Alvaro

2008-01-01

The chemistry of tetralin-1,4-dione, the stable tautomer of 1,4-dihydroxynaphthalene, has not been explored previously. It is readily accessible and offers interesting opportunities for synthesis. The title reactions were explored. L-Selectride reduced the diketone to give preferentially the cis-diol (d.r. 84 : 16). Red-Al gave preferentially the trans-diol (d.r. 13 : 87). NaBH(4), LiAlH(4), and BH(3) gave lower diastereoselectivities (yields: 76-98%). Fractional crystallization allowed isolation of the cis-diol and the trans-diol (55% and 66% yield, respectively). Borane was used to cleanly give the mono-reduction product. Highly enantioselective CBS reductions afforded the trans-diol (72% yield, 99% ee) and the mono-reduction product (81%, 95% ee). Diastereoselective and enantioselective reductions of the unexplored tetralin-1,4-dione provides a very convenient entry into a number of synthetically highly attractive 1,4-tetralindiols and 4-hydroxy-1-tetralone.

Catalytic Enantioselective Synthesis of 3,4-Unsubstituted Thiochromenes through Sulfa-Michael/Julia-Kocienski Olefination Cascade Reaction.

Science.gov (United States)

Simlandy, Amit Kumar; Mukherjee, Santanu

2017-05-05

A highly enantioselective cascade sulfa-Michael/Julia-Kocienski olefination reaction between 2-mercaptobenzaldehydes and β-substituted vinyl PT-sulfones has been realized for the synthesis of 3,4-unsubstituted 2H-thiochromenes. This reaction, catalyzed by diphenylprolinol TMS ether, proceeds through an aromatic iminium intermediate and furnishes a wide range of 2-substiuted 2H-thiochromenes with excellent enantioselectivities (up to 99:1 er).

Enantioselective [3+3] atroposelective annulation catalyzed by N-heterocyclic carbenes

KAUST Repository

Zhao, Changgui; Guo, Donghui; Munkerup, Kristin; Huang, Kuo-Wei; Li, Fangyi; Wang, Jian

2018-01-01

on the transition-metal-catalyzed transformations. Here, we report the enantioselective NHC-catalyzed (NHC: N-heterocyclic carbenes) atroposelective annulation of cyclic 1,3-diones with ynals. In the presence of NHC precatalyst, base, Lewis acid and oxidant, a

Enantioselective synthesis of almorexant via iridium-catalysed intramolecular allylic amidation

NARCIS (Netherlands)

Fananas Mastral, Martin; Teichert, Johannes F.; Fernandez-Salas, Jose Antonio; Heijnen, Dorus; Feringa, Ben L.

2013-01-01

An enantioselective synthesis of almorexant, a potent antagonist of human orexin receptors, is presented. The chiral tetrahydroisoquinoline core structure was prepared via iridium-catalysed asymmetric intramolecular allylic amidation. Further key catalytic steps of the synthesis include an oxidative

Cu(I)-Catalyzed Enantioselective Friedel-Crafts Alkylation of Indoles with 2-Aryl-N-sulfonylaziridines as Alkylating Agents.

Science.gov (United States)

Ge, Chen; Liu, Ren-Rong; Gao, Jian-Rong; Jia, Yi-Xia

2016-07-01

A highly enantioselective Friedel-Crafts alkylation of indoles with N-sulfonylaziridines as alkylating agents has been developed by utilizing the complex of Cu(CH3CN)4BF4/(S)-Segphos as a catalyst. A range of optically active tryptamine derivatives are obtained in good to excellent yields and enantioselectivities (up to >99% ee) via a kinetic resolution process.

Two New Acridone Alkaloids from Glycosmis macrantha

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Abdah Md Akim

2011-05-01

Full Text Available Extraction and chromatographic separation of the extracts of dried stem barks of Glycosmis macrantha lead to isolation of two new acridone alkaloids, macranthanine (1 and 7-hydroxynoracronycine (2, and a known acridone, atalaphyllidine (3. The structures of these alkaloids were determined by detailed spectral analysis and also by comparison with reported data.

Direct asymmetric allylic alkenylation of N-itaconimides with Morita-Baylis-Hillman carbonates

KAUST Repository

Yang, Wenguo

2012-08-03

The asymmetric allylic alkenylation of Morita-Baylis-Hillman (MBH) carbonates with N-itaconimides as nucleophiles has been developed using a commercially available Cinchona alkaloid catalyst. A variety of multifunctional chiral α-methylene-β-maleimide esters were attained in moderate to excellent yields (up to 99%) and good to excellent enantioselectivities (up to 91% ee). The origin of the regio- and stereoselectivity was verified by DFT methods. Calculated geometries and relative energies of various transition states strongly support the observed regio- and enantioselectivity. © 2012 American Chemical Society.

Enantioselective Addition of Allyltin Reagents to Amino Aldehydes Catalyzed with Bis(oxazolinylphenylrhodium(III Aqua Complexes

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Hisao Nishiyama

2011-06-01

Full Text Available Bis(oxazolinylphenylrhodium(III aqua complexes, (PheboxRhX2(H2O [X = Cl, Br], were found to be efficient Lewis acid catalysts for the enantioselective addition of allyl- and methallyltributyltin reagents to amino aldehydes. The reactions proceed smoothly in the presence of 5–10 mol % of (PheboxRhX2(H2O complex at ambient temperature to give the corresponding amino alcohols with modest to good enantioselectivity (up to 94% ee.

New zwitterionic monoterpene indole alkaloids from Uncaria rhynchophylla.

Science.gov (United States)

Guo, Qiang; Yang, Hongshuai; Liu, Xinyu; Si, Xiali; Liang, Hong; Tu, Pengfei; Zhang, Qingying

2018-01-31

Four new zwitterionic monoterpene indole alkaloids, rhynchophyllioniums A-D (1-4), together with eight known alkaloids (5-12), were isolated from the hook-bearing stems of Uncaria rhynchophylla. Their structures were elucidated by extensive spectroscopic data analysis of MS, 1D and 2D NMR, and ECD, and the zwitterionic forms and absolute configurations of 1 and 2 were unambiguously confirmed by single crystal X-ray diffraction analysis. All the isolates, including the monoterpene indole alkaloids with free C-22 carboxyl group and those with C-22 carboxyl methyl ester, were proved to be naturally coexisting in the herb by LC-MS analysis. This is the first report of monoterpene indole alkaloids that exist in the form of zwitterion. Additionally, the cytotoxic activities of all isolates against A549, HepG2, and MCF-7 cell lines are reported. Copyright © 2018 Elsevier B.V. All rights reserved.

Enantioselective synthesis of chiral 3-aryl-1-indanones through rhodium-catalyzed asymmetric intramolecular 1,4-addition.

Science.gov (United States)

Yu, Yue-Na; Xu, Ming-Hua

2013-03-15

Enantioselective synthesis of potentially useful chiral 3-aryl-1-indanones was achieved through a rhodium-catalyzed asymmetric intramolecular 1,4-addition of pinacolborane chalcone derivatives using extraordinary simple MonoPhos as chiral ligand under relatively mild conditions. This novel protocol offers an easy access to a wide variety of enantioenriched 3-aryl-1-indanone derivatives in high yields (up to 95%) with excellent enantioselectivities (up to 95% ee).

Silica-Supported Catalyst for Enantioselective Arylation of Aldehydes under Batch and Continuous-Flow Conditions.

Science.gov (United States)

Watanabe, Satoshi; Nakaya, Naoyuki; Akai, Junichiro; Kanaori, Kenji; Harada, Toshiro

2018-05-04

A silica-supported 3-aryl H 8 -BINOL-derived titanium catalyst exhibited high performance in the enantioselective arylation of aromatic aldehydes using Grignard and organolithium reagents not only under batch conditions but also under continuous-flow conditions. Even with a simple pipet reactor packed with the heterogeneous catalyst, the enantioselective production of chiral diarylmethanols could be achieved through a continuous introduction of aldehydes and mixed titanium reagents generated from the organometallic precursors. The pipet reactor could be used repeatedly in different reactions without appreciable deterioration of the activity.

Isolation, Identification, and Xanthine Oxidase Inhibition Activity of Alkaloid Compound from Peperomia pellucida

Science.gov (United States)

Fachriyah, E.; Ghifari, M. A.; Anam, K.

2018-04-01

The research of the isolation and xanthine oxidation inhibition activity of alkaloid compound from Peperomia pellucida has been carried out. Alkaloid extract is isolated by column chromatography and preparative TLC. Alkaloid isolate is identified spectroscopically by UV-Vis spectrophotometer, FT-IR, and LC-MS/MS. Xanthine oxidase inhibition activity is carried out by in vitro assay. The result showed that the alkaloid isolated probably has piperidine basic structure. The alkaloid isolate has N-H, C-H, C = C, C = O, C-N, C-O-C groups and the aromatic ring. The IC50 values of ethanol and alkaloid extract are 71.6658 ppm and 76.3318 ppm, respectively. Alkaloid extract of Peperomia pellucida showed higher activity than ethanol extract.

Ultrasound-Assisted Enantioselective Esterification of Ibuprofen Catalyzed by a Flower-Like Nanobioreactor

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Baiyi An

2016-04-01

Full Text Available A flower-like nanobioreactor was prepared for resolution of ibuprofen in organic solvents. Ultrasound irradiation has been used to improve the enzyme performance of APE1547 (a thermophilic esterase from the archaeon Aeropyrum pernix K1 in the enantioselective esterification. Under optimum reaction conditions (ultrasound power, 225 W; temperature, 45 °C; water activity, 0.21, the immobilized APE1547 showed an excellent catalytic performance (enzyme activity, 13.26 μmol/h/mg; E value, 147.1. After ten repeated reaction batches, the nanobioreactor retained almost 100% of its initial enzyme activity and enantioselectivity. These results indicated that the combination of the immobilization method and ultrasound irradiation can enhance the enzyme performance dramatically.

NOVEL ALKALOID FROM Rauvolfia capixabae(APOCYNACEAE

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Lanamar Almeida Carlos

2016-02-01

Full Text Available A new sarpagine-type alkaloid, Na-methylrauflorine (1, was isolated from Rauvolfia capixabaetogether with isoreserpiline (2,Nb-oxide-isoreserpiline (3, ajmalicine (4, perakine (5 and vinorine (6 alkaloids. These compounds were characterized based on their spectral data basis, mainly one- (1H, 13C, APT and two-dimensional(1H-1H-COSY, 1H-1H-NOESY, HMQC and HMBC NMR, and mass spectra, also involving comparison with data from the literature.

A survey of Senecio spp. affecting livestock in Uruguay and their associated pyrrolizidine alkaloid content

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Juan Agustín García

2018-02-01

Full Text Available ABSTRACT: In Eastern Uruguay there has been a significant increase of seneciosis in grazing livestock with most affected localities related to counties neighboring the Brazilian border. A survey in 28 farms associated with poisoning outbreaks in grazing cattle in Eastern Uruguay was carried out. Fifty populations of Senecio plants were collected for alkaloid analysis and species identification. Four species were identified: S. oxyphyllus DC, S. madagascariensis Poir, S. brasiliensis (Spreng. Less., and S. selloi DC. Alkaloids were identified by a combination of GC-MS and HPLC-MS analysis and included: retrorsine in S. oxyphyllus; retrorsine, usaramine, and senecivernine/senecionine in S. selloi; retrorsine, senecivernine/senecionine, integerrimine, and usaramine in S. madagascariensis; and integerrimine, retrorsine and senecionine in S. brasiliensis. Total mean alkaloid concentration was reported to be highest in S. brasiliensis (17.6mg/g followed by S. oxyphyllus (6.2mg/g, S. selloi (1.8mg/g and S. madagascariensis (0.6mg/g. Alkaloid concentrations were also reported to be higher in 2015 vs. 2016 probably due to a common environmental factor. The species S. oxyphyllus and S. madagascariensis were not previously recognized as toxic plants in Eastern Uruguay. Particularly, S. oxyphyllus was present in 82% of the farms surveyed and occurred in high density with relative high concentrations of pyrrolizidine alkaloids suggesting S. oxyphyllus may be the main species involved in the reported outbreaks of seneciosis.

Enantioselective γ-Alkylation of α,β-Unsaturated Malonates and Ketoesters by a Sequential Ir-Catalyzed Asymmetric Allylic Alkylation/Cope Rearrangement

OpenAIRE

Liu, Wen-Bo; Okamoto, Noriko; Alexy, Eric J.; Hong, Allen Y.; Tran, Kristy; Stoltz, Brian M.

2016-01-01

A catalytic, enantioselective ? -alkylation of ?,?-unsaturated malonates and ketoesters is reported. This strategy entails a highly regio- and enantioselective iridium-catalyzed ?-alkylation of an extended enolate, and a subsequent translocation of chirality to the ?-position via a Cope rearrangement.

Antimicrobial potential of alkaloids and flavonoids extracted from ...

African Journals Online (AJOL)

Background: Alkaloids and flavonoids are secondary metabolites extracted from different medicinal plants. Tamarix aphylla a traditionally valuable medicinal plant; was used for the extraction of alkaloids and flavonoids in order to evaluate their antibacterial activity. Methodology: The leaves of the plant were collected from ...

Enantioselective developmental toxicity and immunotoxicity of pyraclofos toward zebrafish (Danio rerio)

Energy Technology Data Exchange (ETDEWEB)

Zhuang, Shulin, E-mail: shulin@zju.edu.cn [Institute of Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058 (China); Zhang, Zhisheng [Institute of Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Zhang, Wenjing; Bao, Lingling [Institute of Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058 (China); Xu, Chao, E-mail: chaoxu@zjut.edu.cn [Research Center of Environmental Science, College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032 (China); Zhang, Hu [Institute of Quality and Standard for Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou 210021 (China)

2015-02-15

Highlights: • Pyraclofos has significant enantioselective aquatic toxicities to zebrafish. • Pyraclofos induces time- and concentration-dependent developmental toxicity and immunotoxicity. • The mRNA level of IL-1β gene was significantly up-regulated by pyraclofos. • Pyraclofos binds potently to IL-1β, potentially affecting IL-1β-dependent proinflammatory signal transduction. • Our in vitro and in silico studies help to understand the molecular basis for aquatic toxicity of pyraclofos. - Abstract: Pyraclofos, a relatively new organophosphorus pesticide, has shown potential ecotoxicities, however, its aquatic toxicity, especially enantioselective aquatic toxicity, remains largely unknown. Using zebrafish (Danio rerio) as a preeminent vertebrate aquatic model, the enantioselective differences in the developmental toxicity and immunotoxicity of pyraclofos were evaluated. Following 96-h exposure, pyraclofos enantiomers exhibited acute toxicity and showed lethal concentration 50 of 2.23 and 3.99 mg/L for (R)-Pyraclofos and (S)-Pyraclofos, respectively. Exposure to pyraclofos caused time- and concentration-dependent malformations such as pericardial edema, yolk sac edema, crooked bodies and hatching during the embryonic development, with markedly higher percentages of malformation at higher concentrations. The concentration-dependent immunotoxicity to zebrafish embryo exposed to low level pyraclofos was induced with significant up-regulation of mRNA levels of immune-related interleukin-1β (IL-1β) gene. (R)-Pyraclofos was consistently more toxic than (S)-Pyraclofos for the acute toxicity, developmental toxicity and immunotoxicity to zebrafish. Molecular dynamics simulations revealed that at the atomic level, (R)-Pyraclofos binds more potently to IL-1β protein than (S)-Pyraclofos. This enantioselective binding is mainly contributed by the distinct binding mode of pyraclofos enantiomers and their electrostatic interactions with IL-1β, which potentially

Enantioselective developmental toxicity and immunotoxicity of pyraclofos toward zebrafish (Danio rerio)

International Nuclear Information System (INIS)

Zhuang, Shulin; Zhang, Zhisheng; Zhang, Wenjing; Bao, Lingling; Xu, Chao; Zhang, Hu

2015-01-01

Highlights: • Pyraclofos has significant enantioselective aquatic toxicities to zebrafish. • Pyraclofos induces time- and concentration-dependent developmental toxicity and immunotoxicity. • The mRNA level of IL-1β gene was significantly up-regulated by pyraclofos. • Pyraclofos binds potently to IL-1β, potentially affecting IL-1β-dependent proinflammatory signal transduction. • Our in vitro and in silico studies help to understand the molecular basis for aquatic toxicity of pyraclofos. - Abstract: Pyraclofos, a relatively new organophosphorus pesticide, has shown potential ecotoxicities, however, its aquatic toxicity, especially enantioselective aquatic toxicity, remains largely unknown. Using zebrafish (Danio rerio) as a preeminent vertebrate aquatic model, the enantioselective differences in the developmental toxicity and immunotoxicity of pyraclofos were evaluated. Following 96-h exposure, pyraclofos enantiomers exhibited acute toxicity and showed lethal concentration 50 of 2.23 and 3.99 mg/L for (R)-Pyraclofos and (S)-Pyraclofos, respectively. Exposure to pyraclofos caused time- and concentration-dependent malformations such as pericardial edema, yolk sac edema, crooked bodies and hatching during the embryonic development, with markedly higher percentages of malformation at higher concentrations. The concentration-dependent immunotoxicity to zebrafish embryo exposed to low level pyraclofos was induced with significant up-regulation of mRNA levels of immune-related interleukin-1β (IL-1β) gene. (R)-Pyraclofos was consistently more toxic than (S)-Pyraclofos for the acute toxicity, developmental toxicity and immunotoxicity to zebrafish. Molecular dynamics simulations revealed that at the atomic level, (R)-Pyraclofos binds more potently to IL-1β protein than (S)-Pyraclofos. This enantioselective binding is mainly contributed by the distinct binding mode of pyraclofos enantiomers and their electrostatic interactions with IL-1β, which potentially

[Evaluation of crude drugs by means of colorimeter (I). Study on correlation between color and alkaloids content of coptidis rhizoma].

Science.gov (United States)

Yoshimitsu, Michiyo; Qu, Xian-You; Luo, Wei-Zao; Qin, Song-Yun

2014-05-01

To examine the correlation between alkaloids content and L*, a* and b* color indices of Rhizoma Coptidis for quality control. A colorimeter was used for the measurement of reflected light from sieved powder samples using the CIE 1976 L* a* b* color system. The content of six alkaloids were determined by HPLC. The correlation between alkaloids content and color indices of Rhizoma Coptidis was analyzed. When the particle size of Rhizoma Coptidis was less than 355 microm and the colorimeter parameters were set as measurement diameter of 3 mm, observation degree of 10, and light source of F2 and F7, the measured color was significantly correlated with total alkaloids content (r = 0.793, P < 0.05). As light source of F11, the measured color was significantly correlated with berberine content (r = 0.867, P < 0.01). The correlation between the color of powdered Coptidis Rhizoma and its alkaloids contents was found in this study. Measurment of the color of Coptidis Rhizoma can be used to assess its quality.

Pyrrolizidine alkaloids in the food chain: development, validation, and application of a new HPLC-ESI-MS/MS sum parameter method.

Science.gov (United States)

Cramer, Luise; Schiebel, Hans-Martin; Ernst, Ludger; Beuerle, Till

2013-11-27

Contamination of food and feed with pyrrolizidine alkaloids is currently discussed as a potential health risk. Here, we report the development of a new HPLC-ESI-MS/MS sum parameter method to quantitate the pyrrolizidine alkaloid content in complex food matrices. The procedure was validated for honey and culinary herbs. Isotopically labeled 7-O-9-O-dibutyroyl-[9,9-(2)H2]-retronecine was synthesized and utilized as an internal standard for validation and quantitation. The total pyrrolizidine alkaloid content of a sample is expressed as a single sum parameter: retronecine equivalents (RE). Ld/Lq for honey was 0.1 μg RE/kg/0.3 μg RE/kg. For culinary herbs, 1.0 μg RE/kg/3.0 μg RE/kg (dry weight, dw) and 0.1 μg RE/kg/0.3 μg RE/kg (fresh weight, fw) were determined, respectively. The new method was applied to analyze 21 herbal convenience products. Fifteen products (71%) were pyrrolizidine alkaloid positive showing pyrrolizidine alkaloid concentrations ranging from 0.9 to 74 μg RE/kg fw.

The origin of enantioselectivity in the l-threonine-derived phosphine-sulfonamide catalyzed aza-Morita-Baylis-Hillman reaction: Effects of the intramolecular hydrogen bonding

KAUST Repository

Lee, Richmond

2013-01-01

l-Threonine-derived phosphine-sulfonamide 4 was identified as the most efficient catalyst to promote enantioselective aza-Morita-Baylis-Hillman (MBH) reactions, affording the desired aza-MBH adducts with excellent enantioselectivities. Density functional theory (DFT) studies were carried out to elucidate the origin of the observed enantioselectivity. The importance of the intramolecular N-H⋯O hydrogen-bonding interaction between the sulfonamide and enolate groups was identified to be crucial in inducing a high degree of stereochemical control in both the enolate addition to imine and the subsequent proton transfer step, affording aza-MBH reactions with excellent enantioselectivity. © 2013 The Royal Society of Chemistry.

Novel Euglenoid Derived Alkaloid

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Disclosed herein is a purified toxin isolated from Euglena sanguinea. More specifically the toxin, termed euglenophycin, is an alkaloid having herbicidal and...

Two New Alkaloids from Narcissus serotinus L.

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Francesc Viladomat

2010-10-01

Full Text Available The Amaryllidaceae family is well known for the presence of an exclusive group of alkaloids with a wide range of biological activities. Narcissus serotinus L. is a plant belonging to this family and its geographical distribution is mainly located along the Mediterranean coast. In the present work, specimens collected near Casablanca (Morocco were used to study the alkaloid content of this species. Starting with 350 g of the whole plant we used standard extraction and purification procedures to obtain fractions and compounds for GC-MS and NMR analysis. As well as five known alkaloids, we isolated two new compounds: 1-O-(3´-acetoxybutanoyllycorine and narseronine. The latter has been previously published, but with an erroneous structure.

Exploiting the enantioselectivity of Baeyer-Villiger monooxygenases via boron oxidation

NARCIS (Netherlands)

Brondani, Patricia B.; Dudek, Hanna; Reis, Joel S.; Fraaije, Marco W.; Andrade, Leandro H.

2012-01-01

The enantioselective carbon-boron bond oxidation of several chiral boron-containing compounds by Baeyer-Villiger monooxygenases was evaluated. PAMO and M446G PAMO conveniently oxidized 1-phenylethyl boronate into the corresponding 1-(phenyl)ethanol (ee = 82-91%). Cyclopropyl boronic esters were also

Alkaloid analysis by high-performance liquid chromatography-solid phase extraction-nuclear magnetic resonance

DEFF Research Database (Denmark)

Johansen, Kenneth; Ebild, S.J.; Christensen, S.B.

2012-01-01

%) as methanol-d containing 5% aqueous NHOH (30%) as eluents were successful, even though elution of alkaloids with pK of the corresponding acid above 10 proved difficult. Alkaloid extracts of Huperzia selago containing complex aliphatic alkaloids and Triclisia patens containing bisbenzylisoquinoline alkaloids...

Synthesis of l-threitol-based crown ethers and their application as enantioselective phase transfer catalyst in Michael additions.

Science.gov (United States)

Rapi, Zsolt; Nemcsok, Tamás; Pálvölgyi, Ádám; Keglevich, György; Grün, Alajos; Bakó, Péter

2017-06-01

A few new l-threitol-based lariat ethers incorporating a monoaza-15-crown-5 unit were synthesized starting from diethyl l-tartrate. These macrocycles were used as phase transfer catalysts in asymmetric Michael addition reactions under mild conditions to afford the adducts in a few cases in good to excellent enantioselectivities. The addition of 2-nitropropane to trans-chalcone, and the reaction of diethyl acetamidomalonate with β-nitrostyrene resulted in the chiral Michael adducts in good enantioselectivities (90% and 95%, respectively). The substituents of chalcone had a significant impact on the yield and enantioselectivity in the reaction of diethyl acetoxymalonate. The highest enantiomeric excess (ee) values (99% ee) were measured in the case of 4-chloro- and 4-methoxychalcone. The phase transfer catalyzed cyclopropanation reaction of chalcone and benzylidene-malononitriles using diethyl bromomalonate as the nucleophile (MIRC reaction) was also developed. The corresponding chiral cyclopropane diesters were obtained in moderate to good (up to 99%) enantioselectivities in the presence of the threitol-based crown ethers. © 2017 Wiley Periodicals, Inc.

Effects of motherwort alkaloids on rat ear acne

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Miao Mingsan

2016-04-01

Full Text Available The aim of this study was to explore the effects of motherwort alkaloids on rat ear acne. The rats that were administered high, medium, and low doses of motherwort alkaloids, tanshinone capsules, a model and a control group. Each group of rats was subjected to gavage once daily for 14 consecutive days. On the first day of testing, the control and model groups were administered an intradermal auricle injection of sterilized saline solution and the remaining groups were administered an intradermal auricle injection of Staphylococcus epidermidis in addition to the gavage. The thicknesses of the rats’ auricles were measured for five consecutive days following the injections. Anticoagulated blood was used for erythrocyte rheology index measurement. In addition, the entire ear of each rat was removed for morphological examination. Compared to the model group, the group administered motherwort alkaloids exhibited significantly reduced swelling, improved localized auricle proliferation, and reduced blood viscosity. This result suggests motherwort alkaloids are effective in rat ear acne.

Isolation and structure elucidation of a new indole alkaloid from Rauvolfia serpentina hairy root culture: the first naturally occurring alkaloid of the raumacline group.

Science.gov (United States)

Sheludko, Yuri; Gerasimenko, Irina; Kolshorn, Heinz; Stöckigt, Joachim

2002-05-01

A new monoterpenoid indole alkaloid, 10-hydroxy- N(alpha)-demethyl-19,20-dehydroraumacline ( 1), was isolated as a mixture of E- and Z-isomers from hairy root culture of Rauvolfia serpentina Benth. ex Kurz (Apocynaceae) and the structure was determined by 1D and 2D NMR analyses. The new indole alkaloid represents the first naturally occurring alkaloid of the raumacline group and its putative biosynthetical pathway is discussed.

Pyrones to pyrans: enantioselective radical additions to acyloxy pyrones.

Science.gov (United States)

Sibi, Mukund P; Zimmerman, Jake

2006-10-18

This paper describes a highly site-, diastereo-, and enantioselective intermolecular radical addition/hydrogen atom transfer to hydroxypyrone pyromeconic and kojic acids. The methodology can be extended to the formation of chiral quaternary centers. The products obtained are densely functionalized pyran moieties. The products contain structural features amenable for the introduction of additional substituents.

Chemical Composition and Evaluation of Nicotine, Tobacco Alkaloids, pH, and Selected Flavors in E-Cigarette Cartridges and Refill Solutions.

Science.gov (United States)

Lisko, Joseph G; Tran, Hang; Stanfill, Stephen B; Blount, Benjamin C; Watson, Clifford H

2015-10-01

Electronic cigarette (e-cigarette) use is increasing dramatically in developed countries, but little is known about these rapidly evolving products. This study analyzed and evaluated the chemical composition including nicotine, tobacco alkaloids, pH, and flavors in 36 e-liquids brands from 4 manufacturers. We determined the concentrations of nicotine, alkaloids, and select flavors and measured pH in solutions used in e-cigarettes. E-cigarette products were chosen based upon favorable consumer approval ratings from online review websites. Quantitative analyses were performed using strict quality assurance/quality control validated methods previously established by our lab for the measurement of nicotine, alkaloids, pH, and flavors. Three-quarters of the products contained lower measured nicotine levels than the stated label values (6%-42% by concentration). The pH for e-liquids ranged from 5.1-9.1. Minor tobacco alkaloids were found in all samples containing nicotine, and their relative concentrations varied widely among manufacturers. A number of common flavor compounds were analyzed in all e-liquids. Free nicotine levels calculated from the measurement of pH correlated with total nicotine content. The direct correlation between the total nicotine concentration and pH suggests that the alkalinity of nicotine drives the pH of e-cigarette solutions. A higher percentage of nicotine exists in the more absorbable free form as total nicotine concentration increases. A number of products contained tobacco alkaloids at concentrations that exceed U.S. pharmacopeia limits for impurities in nicotine used in pharmaceutical and food products. © Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Pd(II)-Catalyzed Enantioselective C-H Olefination of Diphenylacetic Acids

Science.gov (United States)

Shi, Bing-Feng; Zhang, Yang-Hui; Lam, Jonathan K.; Wang, Dong-Hui; Yu, Jin-Quan

2009-01-01

Pd(II)-catalyzed enantioselective C-H olefination of diphenylacetic acid substrates has been achieved through the use of mono-protected chiral amino acid ligands. The absolute configuration of the resulting olefinated products is consistent with that of a proposed C-H insertion intermediate. PMID:20017549

Flexible synthesis of poison-frog alkaloids of the 5,8-disubstituted indolizidine-class. II: Synthesis of (--209B, (--231C, (--233D, (--235B", (--221I, and an epimer of 193E and pharmacological effects at neuronal nicotinic acetylcholine receptors

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Garraffo H Martin

2007-09-01

Full Text Available Abstract Background The 5,8-disubstituted indolizidines constitute the largest class of poison-frog alkaloids. Some alkaloids have been shown to act as noncompetitive blockers at nicotinic acetylcholine receptors but the proposed structures and the biological activities of most of the 5,8-disubstituted indolizidines have not been determined because of limited supplies of the natural products. We have therefore conducted experiments to confirm proposed structures and determine biological activities using synthetic compounds. Recently, we reported that one of this class of alkaloids, (--235B', acts as a noncompetitive antagonist for α4β2 nicotinic receptors, and its sensitivity is comparable to that of the classical competitive antagonist for this receptor, dihydro-β-erythroidine. Results The enantioselective syntheses of (--209B, (--231C, (--233D, (--235B", (--221I, and what proved to be an epimer of natural 193E, starting from common chiral lactams have been achieved. When we performed electrophysiological recordings to examine the effects of the synthetic alkaloids on two major subtypes of nicotinic receptors (α4β2 and α7 expressed in Xenopus laevis oocytes, (--231C effectively blocked α4β2 receptor responses (IC50 value, 1.5 μM with a 7.0-fold higher potency than for blockade of α7 receptor responses. In contrast, synthetic (--221I and (--epi-193E were more potent in blocking α7 receptor responses (IC50 value, 4.4 μM and 9.1 μM, respectively than α4β2 receptor responses (5.3-fold and 2.0-fold, respectively. Conclusion We achieved the total synthesis of (--209B, (--231C, (--233D, (--235B", (--221I, and an epimer of 193E starting from common chiral lactams, and the absolute stereochemistry of natural (--233D was determined. Furthermore, the relative stereochemistry of (--231C and (--221I was also determined. The present asymmetric synthesis of the proposed structure for 193E revealed that the C-8 configuration of natural 193E

Experimental and modeling studies on the enantio-separation of 3,5-dinitrobenzoyl-(R),(S)-leucine by continuous liquid-liquid extraction in a cascade of centrifugal contactor separators

NARCIS (Netherlands)

Schuur, Boelo; Winkelman, Jozef G.M.; Vries, Johannes G. de; Heeres, Hero J.

2010-01-01

The continuous enantioselective liquid–liquid extraction of aqueous 3,5-dinitrobenzoyl-(R),(S)-leucine (AR,S) using O-(1-t-butylcarbamoyl)-11-octadecylsulfinyl-10,11-dihydro-quinine (C,a cinchona alkaloid) as extractant in 1,2-dichloroethane (DCE) was studied experimentally in a countercurrently

Enantioselective cytotoxicity of the insecticide bifenthrin on a human amnion epithelial (FL) cell line

International Nuclear Information System (INIS)

Liu Huigang; Zhao Meirong; Zhang Cong; Ma Yun; Liu Weiping

2008-01-01

Synthetic pyrethroids (SPs) are used in preference to organochlorines and organophosphates due to their high efficiency, low toxicity to mammals, and ready biodegradability. Previous studies reported that enantioselective toxicity of SPs occurs in aquatic toxicity. Several studies have indicated that SPs could lead to oxidative damage in humans or animals which was associated with their toxic effects. Little is known about the differences in the effects of chronic toxicity induced by individual stereoisomers of chiral SPs. The present study was therefore undertaken to evaluate the enantioselectivity in cytotoxicity, genotoxicity caused by bifenthrin (BF) on human amnion epithelial (FL) cell lines and pesticidal activity on target organism. The cell proliferation and cytoflow analysis indicated that 1S-cis-BF presented more toxic effects than 1R-cis-BF above the concentration of 7.5 mg L -1 (p > 0.05). FL cells incubated with 1S-cis-BF exhibited a dose-dependent accumulation of intracellular reactive oxygen species (ROS). In the comet assay, the number of cells with damaged DNA incubated with 1S-cis-BF was more than that with 1R-cis-BF (p 50 values of enantiomer to the target pest on Pieris rapae L. show that 1R-cis-BF was 300 times more active than 1S-cis-BF. These results indicate that the enantioselective toxicity and activity of BF between non-target organism and target organism was reversal. These implications together suggest that assessment of the environmental safety and new pesticides development with chiral centers should consider enantioselectivity

New derivatives of alkaloids peganine, vazicinone and garmine

International Nuclear Information System (INIS)

Agedilova, M.T.; Turmukhambetov, A.Zh.; Kazantsev, A.V.; Shul'ts, E.E.

2005-01-01

It was studied the chemical modification of chinazolin alkaloids peganine and vasicinone and indolin alkaloid garmine. The corresponding halogen-, alkyl-, cetyl and hydrazone derivatives and its salts were obtained. The structure of synthesized compounds was definite by following spectral methods: IR, UV, 1 H, 13 C and 11 B NMR spectroscopy

Diversity of the Mountain Flora of Central Asia with Emphasis on Alkaloid-Producing Plants

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Karimjan Tayjanov

2017-02-01

Full Text Available The mountains of Central Asia with 70 large and small mountain ranges represent species-rich plant biodiversity hotspots. Major mountains include Saur, Tarbagatai, Dzungarian Alatau, Tien Shan, Pamir-Alai and Kopet Dag. Because a range of altitudinal belts exists, the region is characterized by high biological diversity at ecosystem, species and population levels. In addition, the contact between Asian and Mediterranean flora in Central Asia has created unique plant communities. More than 8100 plant species have been recorded for the territory of Central Asia; about 5000–6000 of them grow in the mountains. The aim of this review is to summarize all the available data from 1930 to date on alkaloid-containing plants of the Central Asian mountains. In Saur 301 of a total of 661 species, in Tarbagatai 487 out of 1195, in Dzungarian Alatau 699 out of 1080, in Tien Shan 1177 out of 3251, in Pamir-Alai 1165 out of 3422 and in Kopet Dag 438 out of 1942 species produce alkaloids. The review also tabulates the individual alkaloids which were detected in the plants from the Central Asian mountains. Quite a large number of the mountain plants produce neurotoxic and cytotoxic alkaloids, indicating that a strong chemical defense is needed under the adverse environmental conditions of these mountains with presumably high pressure from herbivores.

Detection and quantification of pyrrolizidine alkaloids in antibacterial medical honeys.

Science.gov (United States)

Cramer, Luise; Beuerle, Till

2012-12-01

In recent years, there has been an increasing interest in antibacterial honey for wound care ranging from minor abrasions and burns to leg ulcers and surgical wounds. On the other hand, several recent studies demonstrated that honey for human consumption was contaminated with natural occurring, plant derived pyrrolizidine alkaloids.1,2-Unsaturated pyrrolizidine alkaloids are a group of secondary plant metabolites that show developmental, hepato-, and geno-toxicity as well as carcinogenic effects in animal models and in in vitro test systems. Hence, it was of particular interest to analyze the pyrrolizidine alkaloid content of medical honeys intended for wound care.19 different medical honey samples and/or batches were analyzed by applying a recently established pyrrolizidine alkaloid sum parameter method. 1,2-Unsaturated pyrrolizidine alkaloids were converted into the common necin backbone structures and were analyzed and quantified by GC-MS in the selected ion monitoring mode.All but one medical honey analyzed were pyrrolizidine alkaloid positive. The results ranged from 10.6 µg retronecine equivalents per kg to 494.5 µg retronecine equivalents/kg medical honey. The average pyrrolizidine alkaloid content of all positive samples was 83.6 µg retronecine equivalents/kg medical honey (average of all samples was 79.3 µg retronecine equivalents/kg medical honey). The limit of detection was 2.0 µg retronecine equivalents/kg medical honey, while the limit of quantification was 6.0 µg retronecine equivalents/kg medical honey (S/N > 7/1).Based on the data presented here and considering the fact that medical honeys can be applied to open wounds, it seems reasonable to discuss the monitoring of 1,2-unsaturated pyrrolizidine alkaloids in honey intended for wound treatment. Georg Thieme Verlag KG Stuttgart · New York.

Phytotoxicity of chiral herbicide bromacil: Enantioselectivity of photosynthesis in Arabidopsis thaliana

Energy Technology Data Exchange (ETDEWEB)

Chen, Zunwei; Zou, Yuqin; Wang, Jia [MOE Key Laboratory of Environmental Remediation & Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Li, Meichao [Research Center of Analysis and Measurement, Zhejiang University of Technology, Hangzhou 310032 (China); Wen, Yuezhong, E-mail: wenyuezhong@zju.edu.cn [MOE Key Laboratory of Environmental Remediation & Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China)

2016-04-01

With the wide application of chiral herbicides and the frequent detection of photosystem II (PSII) herbicides, it is of great importance to assess the direct effects of PSII herbicides on photosynthesis in an enantiomeric level. In the present study, the enantioselective phytotoxicity of bromacil (BRO), typical photosynthesis inhibition herbicide, on Arabidopsis thaliana was investigated. The results showed that S-BRO exhibited a greater inhibition of electron transmission in photosystem I (PSI) of A. thaliana than R-BRO by inhibiting the transcription of fnr 1. S-BRO also changed the chlorophyll fluorescence parameters Y (II), Y (NO), and Y (NPQ) to a greater extent than R-Bro. Transcription of genes psbO2, Lhcb3 and Lhcb6 was down-regulated in an enantioselective rhythm and S-BRO caused more serious influence, indicating that S-BRO did worse damage to the photosystem II (PSII) of A. thaliana than R-BRO. This study suggested that S-BRO disturbed the photosynthesis of plants to a larger extent than R-BRO and provided a new sight to evaluate the phytotoxicity of chiral herbicides. - Highlights: • It is necessary to assess the direct effects of PSII herbicides on photosynthesis. • Phytotoxicity of bromacil is investigated in an enantiomeric level. • Bromacil disturbed enantioselectively the photosystem II of Arabidopsis thaliana. • S-bromacil caused severer damage to photosynthesis of Arabidopsis than R-bromacil. • Photosynthesis should be considered for phytotoxicity assessment of herbicides.

Phytotoxicity of chiral herbicide bromacil: Enantioselectivity of photosynthesis in Arabidopsis thaliana

International Nuclear Information System (INIS)

Chen, Zunwei; Zou, Yuqin; Wang, Jia; Li, Meichao; Wen, Yuezhong

2016-01-01

With the wide application of chiral herbicides and the frequent detection of photosystem II (PSII) herbicides, it is of great importance to assess the direct effects of PSII herbicides on photosynthesis in an enantiomeric level. In the present study, the enantioselective phytotoxicity of bromacil (BRO), typical photosynthesis inhibition herbicide, on Arabidopsis thaliana was investigated. The results showed that S-BRO exhibited a greater inhibition of electron transmission in photosystem I (PSI) of A. thaliana than R-BRO by inhibiting the transcription of fnr 1. S-BRO also changed the chlorophyll fluorescence parameters Y (II), Y (NO), and Y (NPQ) to a greater extent than R-Bro. Transcription of genes psbO2, Lhcb3 and Lhcb6 was down-regulated in an enantioselective rhythm and S-BRO caused more serious influence, indicating that S-BRO did worse damage to the photosystem II (PSII) of A. thaliana than R-BRO. This study suggested that S-BRO disturbed the photosynthesis of plants to a larger extent than R-BRO and provided a new sight to evaluate the phytotoxicity of chiral herbicides. - Highlights: • It is necessary to assess the direct effects of PSII herbicides on photosynthesis. • Phytotoxicity of bromacil is investigated in an enantiomeric level. • Bromacil disturbed enantioselectively the photosystem II of Arabidopsis thaliana. • S-bromacil caused severer damage to photosynthesis of Arabidopsis than R-bromacil. • Photosynthesis should be considered for phytotoxicity assessment of herbicides.

Importance of Pyrrolizidine Alkaloids in Bee Products

OpenAIRE

OZANSOY, GÖRKEM; KÜPLÜLÜ, ÖZLEM

2017-01-01

Pyrrolizidinealkaloids are one of the groups of harmful chemicals of plants, which arenatural toxins. Pyrrolizidine alkaloids found in about 3% of all floweringplants of widespread geographical distribution are known as one of thecomponents of the hepatotoxic group of plant origin and referred as hepatotoxicpyrrolizidine alkaloids. According to researches, bee products is regarded asone of the main food sources in the exposure of people to pyrrolizidinealkaloids. Consumption of pyrrolizidine ...

Nerinine and homolycorine, amaryllidaceae alkaloids from the bulbs of Galanthus transcaucasicus Fomin

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M. Babashpour-Asl

2017-01-01

Full Text Available Background and objectives: Many members of the Amaryllidaceae are regarded as toxic. The toxic constituents that occur in the whole family are referred to as the Amaryllidaceae alkaloids. The main aim of this study was the identification of alkaloid compounds from Galanthus transcaucasicus Fomin, a medicinal plant from Amaryllidaceae. Methods: Planar and column chromatography techniques were used for isolation of alkaloid components. GC/MS analysis was carried out for the identification of alkaloid compounds. Results: Silica gel column chromatography of the alkaloidal extract of G. transcaucasicus bulbs afforded seven fractions. Preparative thin layer chromatography of these fractions led to the isolation of compounds 1 (nerinineand 2 (homolycorine. Galantamine was not detected in any of these fractions. Conclusion: Our findings showed that G. transcaucasicus could be a new source of bioactive alkaloids for possible applications in pharmaceutical industries.

Influence of 7,8-methylenedioxylycoctonine-type alkaloids on the toxic effects associated with ingestion of tall larkspur (Delphinium spp) in cattle.

Science.gov (United States)

Welch, Kevin D; Green, Benedict T; Gardner, Dale R; Cook, Daniel; Pfister, James A; Stegelmeier, Bryan L; Panter, Kip E; Davis, T Zane

2010-04-01

To determine the contribution of 7,8-methylenedioxylycoctonine (MDL)-type alkaloids to the toxic effects of tall larkspur (Delphinium spp) consumption in cattle. Sixteen 2-year-old Angus steers. Plant material from 3 populations of tall larkspur that contained different concentration ratios of MDL-type-to-N-(methylsuccinimido) anthranoyllycoctonine (MSAL)-type alkaloids was collected, dried, and finely ground. For each plant population, a dose of ground plant material that would elicit similar clinical signs of toxicosis in cattle after oral administration was determined on the basis of the plants' MSAL-type alkaloid concentration. Cattle were treated via oral gavage with single doses of ground plant material from each of the 3 populations of tall larkspur; each animal underwent 1 to 3 single-dose treatments (> or = 21-day interval between treatments). Heart rate was recorded immediately before (baseline) and 24 hours after each larkspur treatment. Tall larkspur populations with a lower MDL-type-to-MSAL-type alkaloid concentration ratio required a greater amount of MSAL-type alkaloids to cause the expected clinical signs of toxicosis (including increased heart rate) in cattle. Results indicated that the typically less toxic MDL-type alkaloids contributed in a significant manner to the toxic effects of tall larkspur in steers. Consequently, both the concentration of MSAL-type alkaloids and the total concentration of MSAL- and MDL-type alkaloids should be determined when assessing the relative toxicity of tall larkspur populations. These results provide valuable information to determine the risk of toxicosis in cattle grazing on tall larkspur-infested rangelands.

Recognition of pyrrolizidine alkaloid esters in the invasive aquatic plant Gymnocoronis spilanthoides (Asteraceae).

Science.gov (United States)

Boppré, Michael; Colegate, Steven M

2015-01-01

The freshwater aquatic plant Gymnocoronis spilanthoides (Senegal tea plant, jazmín del bañado, Falscher Wasserfreund) is an invasive plant in many countries. Behavioural observations of pyrrolizidine alkaloid-pharmacophagous butterflies suggested the presence of pyrrolizidine alkaloids in the plant. To determine whether the attraction of the butterflies to the plant is an accurate indicator of pyrrolizidine alkaloids in G. spilanthoides. The alkaloid fraction of a methanolic extract of G. spilanthoides was analysed using HPLC with electrospray ionisation MS and MS/MS. Two HPLC approaches were used, that is, a C18 reversed-phase column with an acidic mobile phase, and a porous graphitic carbon column with a basic mobile phase. Pyrrolizidine alkaloids were confirmed, with the free base forms more prevalent than the N-oxides. The major alkaloids detected were lycopsamine and intermedine. The porous graphitic carbon HPLC column, with basic mobile phase conditions, resulted in better resolution of more pyrrolizidine alkaloids including rinderine, the heliotridine-based epimer of intermedine. Based on the MS/MS and high-resolution MS data, gymnocoronine was tentatively identified as an unusual C9 retronecine ester with 2,3-dihydroxy-2-propenylbutanoic acid. Among several minor-abundance monoester pyrrolizidines recognised, spilanthine was tentatively identified as an ester of isoretronecanol with the unusual 2-acetoxymethylbutanoic acid. The butterflies proved to be reliable indicators for the presence of pro-toxic 1,2-dehydropyrrolizidine alkaloids in G. spilanthoides, the first aquatic plant shown to produce these alkaloids. The presence of the anti-herbivory alkaloids may contribute to the plant's invasive capabilities and would certainly be a consideration in any risk assessment of deliberate utilisation of the plant. The prolific growth of the plant and the structural diversity of its pyrrolizidine alkaloids may make it ideal for investigating biosynthetic

BIOACCUMULATION AND ENANTIOSELECTIVE BIOTRANSFORMATION OF FIPRONIL BY RAINBOW TROUT (ONCORHYNCHUS MYKISS)

Science.gov (United States)

Dietary accumulation and enantioselective biotransformation was determined for rainbow trout (Oncorhynchus mykiss) exposed to fipronil, a widely used chiral pesticide. Measurement of the fish carcass tissue (whole fish minus GI tract and liver) showed a rapid accumulation of fip...

Simultaneous determination of the content of isoquinoline alkaloids in Dicranostigma leptopodum (Maxim) Fedde and the effective fractionation of the alkaloids by high-performance liquid chromatography with diode array detection.

Science.gov (United States)

Chen, Yali; Li, Min; Liu, Jianjun; Yan, Qian; Zhong, Mei; Liu, Junxi; Di, Duolong; Liu, Jinxia

2015-01-01

A simple and efficient method was developed for the simultaneous determination of eight isoquinoline alkaloids in methanol extracts of Dicranostigma leptopodum (Maxim) Fedde and the effective fractionation of the alkaloids of D. leptopodum by high-performance liquid chromatography with diode array detection. The chromatographic conditions were optimized on a SinoChrom ODS-BP column to obtain a good separation of the four types of alkaloid analytes, including two aporphines (isocorydine, corydine), two protopines (protopine and allocryptopine), a morphine (sinoacutine), and three quaternary protoberberine alkaloids (berberrubine, 5-hydroxycoptisine, and berberine). The separation of these alkaloids was significantly affected by the composition of the mobile phase, and particularly by its pH value. Acetonitrile (A) and 0.2% phosphoric acid solution adjusted to pH 6.32 with triethylamine (B) were selected as the mobile phase with a gradient elution. With this method, a new quaternary protoberberine alkaloid was isolated and the two structural isomers (isocorydine and corydine) were baseline separated. The appropriate harvest period for D. leptopodum was also recommended based on our analysis. The method for the effective fraction of the alkaloids of D. leptopodum was optimized under this method with regard to the varying significant pharmacological activities of the alkaloids. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Heterosis and heritability estimates of purine alkaloids and ...

African Journals Online (AJOL)

Dry cocoa beans displayed high content of purine alkaloids (2.1 and 8.8 mg g-1 for caffein and theobromine, respectively), and polyphenols (25 and 2978 μg g-1 for catechin and epicatechin, respectively). Among the five cocoa clones, SNK16 was the highest in purine alkaloid (caffein and theobromin) and flavanol ...

Kinetic and dynamic kinetic resolution of secondary alcohols with ionic-surfactant-coated Burkholderia cepacia lipase: substrate scope and enantioselectivity.

Science.gov (United States)

Kim, Cheolwoo; Lee, Jusuk; Cho, Jeonghun; Oh, Yeonock; Choi, Yoon Kyung; Choi, Eunjeong; Park, Jaiwook; Kim, Mahn-Joo

2013-03-15

Forty-four different secondary alcohols, which can be classified into several types (II-IX), were tested as the substrates of ionic surfactant-coated Burkholderia cepacia lipase (ISCBCL) to see its substrate scope and enantioselectivity in kinetic and dynamic kinetic resolution (KR and DKR). They include 6 boron-containing alcohols, 24 chiral propargyl alcohols, and 14 diarylmethanols. The results from the studies on KR indicate that ISCBCL accepted most of them with high enantioselectivity at ambient temperature and with useful to high enantioselectivity at elevated temperatures. In particular, ISCBCL displayed high enantioselectivity toward sterically demanding secondary alcohols (types VIII and IX) which have two bulky substituents at the hydroxymethine center. DKR reactions were performed by the combination of ISCBCL with a ruthenium-based racemization catalyst at 25-60 °C. Forty-one secondary alcohols were tested for DKR. About half of them were transformed into their acetates of high enantiopurity (>90% ee) with good yields (>80%). It is concluded that ISCBCL appears to be a superb enzyme for the KR and DKR of secondary alcohols.

Dual Enantioselective Control using D-phenylglycine-L-proline-derived Catalysts for the Enantioselective Addition of Diethylzinc to Aldehyde

International Nuclear Information System (INIS)

Kang, Seock Yong; Park, Yong Sun

2016-01-01

Dipeptide-derived catalysts are of great interest in various asymmetric transformations because of their short and simple preparation and easy modification of their modular structure by using different α-amino acids. We recently reported the first example of dipeptide-catalyzed enantioselective addition of dialkylzinc to aldehydes. We have developed a novel D-Phg-L-Pro dipeptide-derived catalyst for the addition of diethylzinc to aromatic aldehydes. We also disclosed an effective chiral switching by simply modifying nonchiral part of D-Phg-L-Pro dipeptide.

Pyrrolizidine alkaloids in medicinal tea of Ageratum conyzoides

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Cristiane F. Bosi

2013-06-01

Full Text Available It is now widely-recognized that the view that herbal remedies have no adverse effects and/or toxicity is incorrect; some traditionally-used plants can present toxicity. The well-established popular use of Ageratum conyzoides has led to its inclusion in a category of medicinal crude drugs created by the Brazilian Health Surveillance Agency. Ageratum belongs to the Eupatorieae tribe, Asteraceae, and is described as containing toxic pyrrolizidine alkaloids. Aqueous extracts of Ageratum conyzoides L. harvested in Brazil (commercial, flowering and non-flowering samples were prepared according to the prescribed method and analyzed by HPLC-HRMS. The pyrrolizidine alkaloids lycopsamine, dihydrolycopsamine, and acetyl-lycopsamine and their N-oxides, were detected in the analyzed extracts, lycopsamine and its N-oxide being known hepatotoxins and tumorigens. Together with the pyrrolizidine alkaloids identified by HPLC-HRMS, thirteen phenolic compounds were identified, notably, methoxylated flavonoids and chromenes. Toxicological studies on A. conyzoides are necessary, as is monitoring of its clinical use. To date, there are no established safety guidelines on pyrrolizidine alkaloids-containing plants, and their use in Brazil.

Pyrrolizidine alkaloids in medicinal tea of Ageratum conyzoides

Directory of Open Access Journals (Sweden)

Cristiane F. Bosi

2013-03-01

Full Text Available It is now widely-recognized that the view that herbal remedies have no adverse effects and/or toxicity is incorrect; some traditionally-used plants can present toxicity. The well-established popular use of Ageratum conyzoides has led to its inclusion in a category of medicinal crude drugs created by the Brazilian Health Surveillance Agency. Ageratum belongs to the Eupatorieae tribe, Asteraceae, and is described as containing toxic pyrrolizidine alkaloids. Aqueous extracts of Ageratum conyzoides L. harvested in Brazil (commercial, flowering and non-flowering samples were prepared according to the prescribed method and analyzed by HPLC-HRMS. The pyrrolizidine alkaloids lycopsamine, dihydrolycopsamine, and acetyl-lycopsamine and their N-oxides, were detected in the analyzed extracts, lycopsamine and its N-oxide being known hepatotoxins and tumorigens. Together with the pyrrolizidine alkaloids identified by HPLC-HRMS, thirteen phenolic compounds were identified, notably, methoxylated flavonoids and chromenes. Toxicological studies on A. conyzoides are necessary, as is monitoring of its clinical use. To date, there are no established safety guidelines on pyrrolizidine alkaloids-containing plants, and their use in Brazil.

Calcium, membranes and accumulation of alkaloids in plants

International Nuclear Information System (INIS)

Lovkova, M.Ya.; Buzuk, G.N.; Grinkevich, N.I.

1983-01-01

Ca 2+ effect upon metabolism of aporphines and protopines has been studied in Glaucium flavun, which alkaloids are of an essential interest for the medicine practice. It has been shown that calcium produces the inhibiting effect both on catabolitic splitting and metabolism of glaucine and protopine. It has been anticipated that calcuium introduced into an expert plant stabilizes membranes of intracellular structures and prevents 14 C alkaloid entering from an environment to metabolically active cell compartments, which contain ferments realizing transformations of the above compounds. The level of membrane permeability is probably the main mechanism, through which a control of metabolism processes occurs, and hence, a control of alkaloid accumulation processes under in vivo conditions

Enantioselective Evans-Tishchenko Reduction of b-Hydroxyketone Catalyzed by Lithium Binaphtholate

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Makoto Nakajima

2011-06-01

Full Text Available Lithium diphenylbinaphtholate catalyzed the enantioselective Evans-Tishchenko reduction of achiral b-hydroxyketones to afford monoacyl-protected 1,3-diols with high stereoselectivities. In the reaction of racemic b-hydroxyketones, kinetic optical resolution occurred in a highly stereoselective manner.

Toxic effects, metabolism, and carry-over of ergot alkaloids in laying hens, with a special focus on changes of the alkaloid isomeric ratio in feed caused by hydrothermal treatment.

Science.gov (United States)

Dänicke, Sven

2016-02-01

Ergot alkaloids (EA) are mycotoxins formed by Claviceps purpurea. Due to the large variation in EA content, the mass proportion of ergot (hardened sclerotia) in animal diets is not suited to establish safe levels of EA. Therefore, the aim of the present study was to examine the dose-dependent effects of dietary EA on laying hens. Ergoty rye or ergot-free rye (control diet) was included in the diets either untreated or after hydrothermal treatment ("expansion"). The total EA levels in five different diets containing 0-3% of untreated or expanded rye were 0.1-14.56 mg/kg (untreated rye) and 0.08-13.03 mg/kg (expanded rye). The average EA reduction amounted to 11% due to expanding. The proportions of the sum of all -inine isomers however were consistently higher (19.5-48.4%) compared to the sum of their -ine isomer counterparts which decreased at the same time. Most of the laying performance and reproductive traits were significantly compromised during the test period between weeks 22 and 42 of age when the diet with the highest EA content was fed. Toxic effects were less pronounced due to expanding. Relative weights of liver, proventriculus, and gizzard as well as the aspartate aminotransferase activity, the antibody titers to Newcastle disease virus, albumin, and total bilirubin concentrations were all significantly increased in hens fed at the highest dietary ergot level whereby expanding additionally modified the albumin and total bilirubin responses. No carry-over of EA into egg yolk and albumen, blood, liver, and breast muscle was found, but bile contained quantifiable levels of ergometrine and ergometrinine. Biological recovery of ingested individual alkaloids with the excreta varied from 2 to 22% and was strongly positive linearly related to the octanol to water partition coefficient (logkOW). This suggests the lipophilicity of alkaloids as a factor influencing their metabolism and elimination. Based on the overall results of this study, a lowest observed

Asymmetric NHC-catalyzed aza-Diels-Alder reactions: Highly enantioselective route to α-amino acid derivatives and DFT calculations

KAUST Repository

Yang, Limin

2014-08-01

A facile N-heterocyclic carbene catalytic enantioselective aza-Diels-Alder reaction of oxodiazenes with α-chloroaldehydes as dienophile precursors is reported, with excellent enantioselectivity (ee > 99%) and excellent yield (up to 93%). DFT study showed that cis-TSa, formed from a top face approach of oxodiazene to cis-IIa, is the most favorable transition state and is consistent with the experimental observations. © 2014 American Chemical Society.

Occurrence of theobromine synthase genes in purine alkaloid-free species of Camellia plants.

Science.gov (United States)

Ishida, Mariko; Kitao, Naoko; Mizuno, Kouichi; Tanikawa, Natsu; Kato, Misako

2009-02-01

Caffeine (1,3,7-trimethylxanthine) and theobromine (3,7-dimethylxanthine) are purine alkaloids that are present in high concentrations in plants of some species of Camellia. However, most members of the genus Camellia contain no purine alkaloids. Tracer experiments using [8-(14)C]adenine and [8-(14)C]theobromine showed that the purine alkaloid pathway is not fully functional in leaves of purine alkaloid-free species. In five species of purine alkaloid-free Camellia plants, sufficient evidence was obtained to show the occurrence of genes that are homologous to caffeine synthase. Recombinant enzymes derived from purine alkaloid-free species showed only theobromine synthase activity. Unlike the caffeine synthase gene, these genes were expressed more strongly in mature tissue than in young tissue.

New alkaloids of the sarpagine group from Rauvolfia serpentina hairy root culture.

Science.gov (United States)

Sheludko, Yuri; Gerasimenko, Irina; Kolshorn, Heinz; Stöckigt, Joachim

2002-07-01

Three new monoterpenoid indole alkaloids, 19(S),20(R)-dihydroperaksine (1), 19(S),20(R)-dihydroperaksine-17-al (2), and 10-hydroxy-19(S),20(R)-dihydroperaksine (3), along with 16 known alkaloids 4-19 were isolated from hairy root culture of Rauvolfia serpentina, and their structures were elucidated by 1D and 2D NMR analyses. Taking into account the stereochemistry of the new alkaloids and results of preliminary enzymatical studies, the putative biosynthetical relationships between the novel alkaloids are discussed.

[Comparative study on alkaloids of tissue-culture seedling and wild plant of Dendrobium huoshanense ].

Science.gov (United States)

Chen, Nai-dong; Gao, Feng; Lin, Xin; Jin, Hui

2014-06-01

To compare the composition and content of alkaloid of Dendrobium huoshanense tissue-culture seedling and wild plant. A comparative evaluation on the quality was carried out by HPLC and TLC methods including the composition and the content of alkaloids. Remarkable variation existed in the two kinds of Dendrobium huoshanense. For the tissue-culture plant, only two alkaloids were checked out by both HPLC and TLC while four alkaloids were observed in the wild plant. The alkaloid content of tissue-culture seedling and wild plant was(0. 29 ± 0. 11)%o and(0. 43 ± 0. 15) %o,respectively. Distinguished difference is observed in both composition and content of alkaloids from the annual shoots of different provenances of Dendrobium huoshanense. It suggested that the quality of tissue-culture seedling of Dendrobium huoshanense might be inconsistent with the wild plant. Furthermore, the established alkaloids-knock-out HPLC method would provide a new research tool on quality control of Chinese medicinal materials which contain unknown alkaloids.

Alkaloids in the human food chain - Natural occurrence and possible adverse effects

NARCIS (Netherlands)

Koleva, I.; Beek, van T.A.; Soffers, A.E.M.F.; Dusemund, B.; Rietjens, I.

2012-01-01

Alkaloid-containing plants are an intrinsic part of the regular Western diet. The present paper summarizes the occurrence of alkaloids in the food chain, their mode of action and possible adverse effects including a safety assessment. Pyrrolizidine alkaloids are a reason for concern because of their

Pyrrolizidine alkaloids from seven wild-growing Senecio species in Serbia and Montenegro

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BORIS M. MANDIC

2009-01-01

Full Text Available The genus Senecio (family Asteraceae is one of the largest in the world. It comprises about 1100 species which are the rich source of pyrrolizidine alkaloids. Plants containing pyrrolizidine alkaloids are among the most important sources of human and animal exposure to plant toxins and carcinogens. The pyrrolizidine alkaloids of seven Senecio species (S. erucifolius, S. othonnae, S. wagneri, S. subalpinus, S. carpathicus, S. paludosus and S. rupestris were studied. Fourteen alkaloids were isolated and their structures determined from spectroscopic data (1H- and 13C-NMR, IR and MS. Five of them were identified in S. erucifolius, four in S. othonnae, two in S. wagneri, four in S. subalpinus, two in S. carpathicus, three in S. paludosus and three in S. rupestris. Seven pyrrolizidine alkaloids were found for the first time in particular species. The results have chemotaxonomic importance. The cytotoxic activity and antimicrobial activity of some alkaloids were also studied.

Application of Phosphine-Phosphite Ligands in the Iridium Catalyzed Enantioselective Hydrogenation of 2-Methylquinoline

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Miguel Rubio

2010-10-01

Full Text Available The hydrogenation of 2-methylquinoline with Ir catalysts based on chiral phosphine-phosphites has been investigated. It has been observed that the reaction is very sensitive to the nature of the ligand. Optimization of the catalyst, allowed by the highly modular structure of these phosphine-phosphites, has improved the enantioselectivity of the reaction up to 73% ee. The influence of additives in this reaction has also been investigated. Contrary to the beneficial influence observed in related catalytic systems, iodine has a deleterious effect in the present case. Otherwise, aryl phosphoric acids produce a positive impact on catalyst activity without a decrease on enantioselectivity.

Enantioselective synthesis of alpha,beta-disubstituted-beta-amino acids.

Science.gov (United States)

Sibi, Mukund P; Prabagaran, Narayanasamy; Ghorpade, Sandeep G; Jasperse, Craig P

2003-10-01

Highly diastereoselective and enantioselective addition of N-benzylhydroxylamine to imides 17 and 20-30 produces alpha,beta-trans-disubstituted N-benzylisoxazolidinones 19 and 31-41. These reactions proceed in 60-96% ee with 93-99% de's using 5 mol % of Mg(NTf2)2 and ligand 18. The product isoxazolidinones can be hydrogenolyzed directly to provide alpha,beta-disubstituted-beta-amino acids.

Pharmacological actions of Uncaria alkaloids, rhynchophylline and isorhynchophylline.

Science.gov (United States)

Shi, Jing-Shan; Yu, Jun-Xian; Chen, Xiu-Ping; Xu, Rui-Xia

2003-02-01

The pharmacological actions of Uncaria alkaloids, rhynchophylline and isorhynchophylline extracted from Uncaria rhynchophylla Miq Jacks were reviewed. The alkaloids mainly act on cardiovascular system and central nervous system including the hypotension, brachycardia, antiarrhythmia, and protection of cerebral ischemia and sedation. The active mechanisms were related to blocking of calcium channel, opening of potassium channel, and regulating of nerve transmitters transport and metabolism, etc.

[Recent results on the pharmacodynamics of Strychnos malgaches alkaloids].

Science.gov (United States)

Rasoanaivo, P; Ratsimamanga-Urverg, S; Frappier, F

1996-01-01

Investigation of Strychnos (Loganiaceae) shrubs and trees was initiated by their traditional uses of their inherent poisons on arrows: this led to the discovery of strychnine and curare alkaloids. Subsequently, phytochemical investigation of several Strychnos species has shown great structural diversity of the alkaloid constituent which also display various biological effects, i.e. convulsive and relaxant effects on muscles, and antimicrobial, antitumor and antihypertensive properties. Ethnobotanical field work conducted in different regions of Madagascar revealed that infusion of three Strychnos species, S. mostueoides, S. myrtoides and S. diplotricha, is used in association with subcurative doses of chloroquine to treat chronic malaria. Bioassayfractionation led to the isolation of two major bioactive components, strychnobrasiline and malagashanine. Whereas strychnobrasiline is a previously known chemical compound, malagashanine is the first in a series of a new subtype of Strychnos alkaloids. These two alkaloids are devoid of intrinsic antimalarial effects, both in vitro (IC50 = 73.0 micrograms/ml for strychnobrasiline and 69.1 micrograms/ml for malagashanine) and in vivo (10 mg/kg conferred a 5% suppression of parasitemia). When these alkaloids are combined with chloroquine at doses much lower than required for antiplasmodial effects, they greatly enhance the chloroquine action in a dose dependent manner as seen by the isobologram method. Several minor alkaloids structurally related to malagashanine were also isolated from Madagascan Strychnos. They all enhance, to greater or lesser degrees, the chloroquine effectiveness. Interestingly, there is a positive correlation between the ethnomedical use of the three Strychnos species as chloroquine adjuvants and the chloroquine-potentiating effects of malagashanine and strychnobrasiline isolated from them. After preliminary toxicological studies, infusion of stem barks of S. myrtoides in association with chloroquine

The expanding universe of alkaloid biosynthesis.

Science.gov (United States)

De Luca, V; Laflamme, P

2001-06-01

Characterization of many of the major gene families responsible for the generation of central intermediates and for their decoration, together with the development of large genomics and proteomics databases, has revolutionized our capability to identify exotic and interesting natural-product pathways. Over the next few years, these tools will facilitate dramatic advances in our knowledge of the biosynthesis of alkaloids, which will far surpass that which we have learned in the past 50 years. These tools will also be exploited for the rapid characterization of regulatory genes, which control the development of specialized cell factories for alkaloid biosynthesis.

Catalytic enantioselective alkene aminohalogenation/cyclization involving atom transfer.

Science.gov (United States)

Bovino, Michael T; Chemler, Sherry R

2012-04-16

Problem solved: the title reaction was used for the synthesis of chiral 2-bromo, chloro, and iodomethyl indolines and 2-iodomethyl pyrrolidines. Stereocenter formation is believed to occur by enantioselective cis aminocupration and C-X bond formation is believed to occur by atom transfer. The ultility of the products as versatile synthetic intermediates was demonstrated, as was a radical cascade cyclization sequence. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rhodium-catalyzed enantioselective intramolecular C-H silylation for the syntheses of planar-chiral metallocene siloles.

Science.gov (United States)

Zhang, Qing-Wei; An, Kun; Liu, Li-Chuan; Yue, Yuan; He, Wei

2015-06-01

Reported herein is the rhodium-catalyzed enantioselective C-H bond silylation of the cyclopentadiene rings in Fe and Ru metallocenes. Thus, in the presence of (S)-TMS-Segphos, the reactions took place under very mild conditions to afford metallocene-fused siloles in good to excellent yields and with ee values of up to 97%. During this study it was observed that the steric hindrance of chiral ligands had a profound influence on the reactivity and enantioselectivity of the reaction, and might hold the key to accomplishing conventionally challenging asymmetric C-H silylations. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An enantioselective approach toward 3,4-dihydroisocoumarin through the bromocyclization of styrene-type carboxylic acids.

Science.gov (United States)

Chen, Jie; Zhou, Ling; Tan, Chong Kiat; Yeung, Ying-Yeung

2012-01-20

A facile and enantioselective approach toward 3,4-dihydroisocoumarin was developed. The method involved an amino-thiocarbamate catalyzed enantioselective bromocyclization of styrene-type carboxylic acids, yielding 3-bromo-3,4-dihydroisocoumarins with good yields and ee's. 3-Bromo-3,4-dihydroisocoumarins are versatile building blocks for various dihydroisocoumarin derivatives in which the Br group can readily be modified to achieve biologically important 4-O-type and 4-N-type 3,4-dihydroisocoumarin systems. In addition, studies indicated that, by refining some parameters, the synthetically useful 5-exo phthalide products could be achieved with good yields and ee's.

A Green, Enantioselective Synthesis of Warfarin for the Undergraduate Organic Laboratory

Science.gov (United States)

Wong, Terence C.; Sultana, Camille M.; Vosburg, David A.

2010-01-01

The enantioselective synthesis of drugs is of fundamental importance in the pharmaceutical industry. In this experiment, students synthesize either enantiomer of warfarin, a widely used anticoagulant, in a single step from inexpensive starting materials. Stereoselectivity is induced by a commercial organocatalyst, ("R","R")- or…

Rhodium-Catalyzed Enantioselective Cyclopropanation of Olefins with N-Sulfonyl 1,2,3-Triazoles

Science.gov (United States)

Chuprakov, Stepan; Kwok, Sen Wai; Zhang, Li; Lercher, Lukas; Fokin, Valery V.

2009-01-01

N-Sulfonyl 1,2,3-triazoles readily form rhodium(II) azavinyl carbenes, which react with olefins to produce cyclopropanes with excellent diastereo- and enantioselectivity and in high yield. PMID:19928917

Analytical chemical study of alkaloid fraction of methanolic extract of Croton baillonianus (AUBL) leaves

International Nuclear Information System (INIS)

Fuertes R, Cesar M.; Benavides, Angelyne; Pizza, Cosimo; Napolitano, Asunta; Basarello, Carla; Piacente, Sonia; Carbone Virginia

2012-01-01

The objective of the present study has been to extract and isolate the alkaloids from leaves of Croton baillonianus, corresponding to the methanolic extract by exclusion chromatography with Sephadex LH-20 followed by a purification by high performance liquid chromatography, obtaining six alkaloids. Two low polarity alkaloid and two glycoside alkaloids were analyzed by Electronic System impact mass spectrometry; these alkaloids belong to bencylisoquinolinic type; the study has connection to the determination of its antioxidant, antiulcerose and cytotoxic properties. (author).

Profiling the indole alkaloids in yohimbe bark with ultra-performance liquid chromatography coupled with ion mobility quadrupole time-of-flight mass spectrometry.

Science.gov (United States)

Sun, Jianghao; Baker, Andrew; Chen, Pei

2011-09-30

An ultra-performance liquid chromatography/ion mobility quadrupole time-of-flight mass spectrometry (UPLC/IM-QTOF-MS) method was developed for profiling the indole alkaloids in yohimbe bark. Many indole alkaloids with the yohimbine or ajmalicine core structure, plus methylated, oxidized and reduced species, were characterized. Common fragments and mass differences are described. It was shown that the use of IMS could provide another molecular descriptor, i.e. molecular shape by rotationally averaged collision cross-section; this is of great value for identification of constituents when reference materials are usually not available. Using the combination of high resolution (~40000) accurate mass measurement with time-aligned parallel (TAP) fragmentation, MS(E) (where E represents collision energy), ion mobility mass spectrometry (IMS) and UPLC chromatography, a total 55 indole alkaloids were characterized and a few new indole alkaloids are reported for the first time. Published in 2011 by John Wiley & Sons, Ltd.

Optimisation of stabilised carboxylesterase NP for enantioselective hydrolysis of naproxen methyl ester

CSIR Research Space (South Africa)

Steenkamp, Lucia H

2008-12-01

Full Text Available Although the enantioselective kinetic resolution of ester racemates of the non-steroidal antiinflammatory drug naproxen ([2-(6-methoxy-2-naphthyl) propionic acid]) is a common demonstration for biocatalysis, the enantiomeric excess of the reactions...

A new strain of Claviceps purpurea accumulating tetracyclic clavine alkaloids.

Science.gov (United States)

Schumann, B; Erge, D; Maier, W; Gröger, D

1982-05-01

A new strain of Claviceps was isolated from a blokked mutant of Claviceps purpurea. This strain accumulates substantial amounts of clavine alkaloids (2 g/l). The alkaloid fraction is composed of chanoclavine-I ( approximately 10%) and a mixture of agroclavine/elymoclavine (90%). Most suitable for alkaloid production in submerged culture is an ammoncitrate/sucrose medium. The genealogy of the new strain, designated Pepty 695/ch-I is the following one: Pepty 695/S (ergotoxine producer) --> Pepty 695/ch (secoergoline producer) --> Pepty 695/ch-I (tetracyclic clavine producer).

An experimental study of radioprotective effect of ginseng alkaloid fraction on cellular damage

Energy Technology Data Exchange (ETDEWEB)

Yoo, Seong Yul; Cho, Chul Koo; Kim, Mi Sook; Yoo, Hyung Jun; Kim, Seong Ho; Kim, Tae Hwan [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

1997-09-01

This paper is to assess the effect of Adaptagen as a radioprotector in which main component is alkaloid fraction of ginseng. Evaluation was made in vitro and in vivo study with NIGP(S) mouse by the measurement of regeneration of jejunal crypt cell and micronucleus assay to analyze radioprotective effect of ginseng alkaloid fraction in comparison with that of water fraction after whole body irradiation. The results were as follows, 1. The degree of radiation damage of mouse jejunal crypt cell was diminished in both of alkaloid and water fraction groups compared to control group but more in alkaloid fraction group than water fraction group. 2. Regeneration of mouse jejunal crypt cell was higher both in alkaloid and water fraction groups than control group. 3. In vitro study, frequency of micronucleus was diminished in tendency for the treated groups than control group but statistically insignificant. 4. In vitro study, frequency of micronucleus was diminished in both alkaloid and water fraction groups compared to control group but more in alkaloid fraction group than water fraction group.

Combinatorial library based engineering of Candida antarctica lipase A for enantioselective transacylation of sec-alcohols in organic solvent.

Science.gov (United States)

Wikmark, Ylva; Svedendahl Humble, Maria; Bäckvall, Jan-E

2015-03-27

A method for determining lipase enantioselectivity in the transacylation of sec-alcohols in organic solvent was developed. The method was applied to a model library of Candida antarctica lipase A (CalA) variants for improved enantioselectivity (E values) in the kinetic resolution of 1-phenylethanol in isooctane. A focused combinatorial gene library simultaneously targeting seven positions in the enzyme active site was designed. Enzyme variants were immobilized on nickel-coated 96-well microtiter plates through a histidine tag (His6-tag), screened for transacylation of 1-phenylethanol in isooctane, and analyzed by GC. The highest enantioselectivity was shown by the double mutant Y93L/L367I. This enzyme variant gave an E value of 100 (R), which is a dramatic improvement on the wild-type CalA (E=3). This variant also showed high to excellent enantioselectivity for other secondary alcohols tested. © 2015 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution Non-Commercial NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Cyclobutane-Containing Alkaloids: Origin, Synthesis, and Biological Activities

OpenAIRE

Sergeiko, Anastasia; Poroikov, Vladimir V; Hanuš, Lumir O; Dembitsky, Valery M

2008-01-01

Present review describes research on novel natural cyclobutane-containing alkaloids isolated from terrestrial and marine species. More than 60 biological active compounds have been confirmed to have antimicrobial, antibacterial, antitumor, and other activities. The structures, synthesis, origins, and biological activities of a selection of cyclobutane-containing alkaloids are reviewed. With the computer program PASS some additional biological activities are also predicted, which point toward ...

DNA-based asymmetric catalysis : Sequence-dependent rate acceleration and enantioselectivity

NARCIS (Netherlands)

Boersma, Arnold J.; Klijn, Jaap E.; Feringa, Ben L.; Roelfes, Gerard

2008-01-01

This study shows that the role of DNA in the DNA-based enantioselective Diels-Alder reaction of azachalcone with cyclopentadiene is not limited to that of a chiral scaffold. DNA in combination with the copper complex of 4,4'-dimethyl-2,2'-bipyridine (Cu-L1) gives rise to a rate acceleration of up to

Mass-spectrometry-directed analysis and purification of pyrrolizidine alkaloid cis/trans isomers in Gynura japonica.

Science.gov (United States)

Fang, Lianxiang; Xiong, Aizhen; Yang, Xiao; Cheng, Wenzhi; Yang, Li; Wang, Zhengtao

2014-08-01

Pyrrolizidine alkaloids are highly hepatotoxic natural chemicals that produce irreversible chronic and acute hepatotoxic effects on human beings. Purification of large amounts of pyrrolizidine alkaloids is necessary for toxicity studies. In this study, an efficient method for targeted analysis and purification of pyrrolizidine alkaloid cis/trans isomers from herbal materials was developed for the first time. Targeted analysis of the hepatotoxic pyrrolizidine alkaloids was performed by liquid chromatography with tandem mass spectrometry (precursor ion scan and daughter ion scan), and the purification of pyrrolizidine alkaloids was achieved with a mass-directed auto purification system. The extraction and preparative liquid chromatography conditions were optimized. The developed method was applied to analysis of Gynura japonica (Thunb.) Juel., a herbal medicine traditionally used for detumescence and relieving pain but is potentially hepatotoxic as it contains pyrrolizidine alkaloids. Twelve pyrrolizidine alkaloids (six cis/trans isomer pairs) were identified with reference compounds or characterized by liquid chromatography with tandem mass spectrometry, and five individual pyrrolizidine alkaloids, including (E)-seneciphylline, seneciphylline, integerrimine, senecionine, and seneciphyllinine, were prepared from G. japonica roots with high efficiency. The results of this work provide a new technique for the preparation of large amounts of pyrrolizidine alkaloid reference substances, which will also benefit toxicological studies of pyrrolizidine alkaloids and treatments for pyrrolizidine alkaloid-induced toxicity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Histrionicotoxin alkaloids finally detected in an ant

DEFF Research Database (Denmark)

Jones, Tappey H.; Adams, Rachelle Martha Marie; Spande, Thomas F.

2012-01-01

Workers of the ant Carebarella bicolor collected in Panama were found to have two major poison-frog alkaloids, cis- and trans-fused decahydroquinolines (DHQs) of the 269AB type, four minor 269AB isomers, two minor 269B isomers, and three isomers of DHQ 271D. For the first time in an ant, however......) sp., were found to have a very similar DHQ complex but failed to show HTXs. Several new DHQ alkaloids of MW 271 (named in the frog as 271G) are reported from the above ants that have both m/z 202 and 204 as major fragment ions, unlike the spectrum seen for the poison-frog alkaloid 271D, which has...... only an m/z 204 base peak. Found also for the first time in skin extracts from the comparison frog Oophaga granulifera of Costa Rica is a trace DHQ of MW 273. It is coded as 273F in the frog; a different isomer is found in the ant....

Primary amine/CSA ion pair: A powerful catalytic system for the asymmetric enamine catalysis

KAUST Repository

Liu, Chen; Zhu, Qiang; Huang, Kuo-Wei; Lu, Yixin

2011-01-01

A novel ion pair catalyst containing a chiral counteranion can be readily derived by simply mixing cinchona alkaloid-derived diamine with chiral camphorsulfonic acid (CSA). A mixture of 9-amino(9-deoxy)epi-quinine 8 and (-)-CSA was found to be the best catalyst with matching chirality, enabling the direct amination of α-branched aldehydes to proceed in quantitative yields and with nearly perfect enantioselectivities. A 0.5 mol % catalyst loading was sufficient to catalyze the reaction, and a gram scale enantioselective synthesis of biologically important α-methyl phenylglycine has been successfully demonstrated. © 2011 American Chemical Society.

Primary amine/CSA ion pair: A powerful catalytic system for the asymmetric enamine catalysis

KAUST Repository

Liu, Chen

2011-05-20

A novel ion pair catalyst containing a chiral counteranion can be readily derived by simply mixing cinchona alkaloid-derived diamine with chiral camphorsulfonic acid (CSA). A mixture of 9-amino(9-deoxy)epi-quinine 8 and (-)-CSA was found to be the best catalyst with matching chirality, enabling the direct amination of α-branched aldehydes to proceed in quantitative yields and with nearly perfect enantioselectivities. A 0.5 mol % catalyst loading was sufficient to catalyze the reaction, and a gram scale enantioselective synthesis of biologically important α-methyl phenylglycine has been successfully demonstrated. © 2011 American Chemical Society.

Actions of piperidine alkaloid teratogens at fetal nicotinic acetylcholine receptors.

Science.gov (United States)

Green, Benedict T; Lee, Stephen T; Panter, Kip E; Welch, Kevin D; Cook, Daniel; Pfister, James A; Kem, William R

2010-01-01

Teratogenic alkaloids are found in many species of plants including Conium maculatum L., Nicotiana glauca, Nicotiana tabaccum, and multiple Lupinus spp. Fetal musculoskeletal defects produced by alkaloids from these plants include arthrogyropisis, scoliosis, torticollis, kyposis, lordosis, and cleft palate. A pharmacodynamic comparison of the alkaloids ammodendrine, anabasine, anabaseine, anagyrine, and coniine in SH-SY5Y cells and TE-671 cells was made. These alkaloids and their enantiomers were more effective in depolarizing TE-671 cells which express the human fetal-muscle type nicotinic acetylcholine receptor (nAChR) relative to SH-SY5Y cells which predominately express autonomic nAChRs. The rank order of potency in TE-671 cells was: anabaseine>(+)-anabasine>(-)-anabasine > (+/-)-anabasine>anagyrine>(-)-coniine > (+/-)-coniine>(+)-coniine>(+/-)-ammodendrine>(+)-ammodendrine. The rank order potency in SH-SY5Y cells was: anabaseine>(+)-anabasine>(-)-coniine>(+)-coniine>(+)-ammodendrine>anagyrine>(-)-anabasine>(+/-)-coniine>(+/-)-anabasine>(-)-ammodendrine. The actions of these alkaloids at nAChRs in both cell lines could be distinguished by their maximum effects in depolarizing cell membrane potential. The teratogenic action of these compounds may be related to their ability to activate and subsequently desensitize nAChRs.

Quinolizidine alkaloids from the curare adjuvant Clathrotropis glaucophylla.

Science.gov (United States)

Sagen, Anne Lise; Gertsch, Jürg; Becker, Rita; Heilmann, Jörg; Sticher, Otto

2002-12-01

The bark of Clathrotropis glaucophylla (Fabaceae) is used as admixture of curare arrow poison by the Yanomami; Amerindians in Venezuela. A new quinolizidine alkaloid (QA), (-)-13alpha-hydroxy-15alpha-(1-hydroxyethyl)-anagyrine [(-)-clathrotropine], was isolated from the alkaloid extract of C. glaucophylla bark, together with eleven known QAs: (-)-anagyrine, (-)-thermopsine, (-)-baptifoline, (-)-epibaptifoline, (-)-rhombifoline, (-)-tinctorine, (-)-cytisine, (-)-N-methylcytisine, (-)-lupanine, (-)-6alpha-hydroxylupanine and (+)-5,6-dehydrolupanine. The isolation and structure elucidation were performed with the aid of chromatographic (TLC, HPLC and CC) and spectroscopic (UV and 1D/2D NMR) methods, and mass spectrometry. To our knowledge, this is the first time quinolizidine alkaloids have been isolated from an arrow poison ingredient. It is also the first report on Clathrotropis species being used for preparation of arrow poison.

Indolopyridoquinazoline alkaloids from Esenbeckia grandiflora mart. (Rutaceae); Alkaloides {beta}-indolopiridoquinazolinicos de Esenbeckia grandiflora mart. (Rutaceae)

Energy Technology Data Exchange (ETDEWEB)

Januario, Ana Helena; Vieira, Paulo Cezar; Silva, Maria Fatima das Gracas Fernandes da; Fernandes, Joao Batista [Universidade Federal de Sao Carlos (UFSCAR), SP (Brazil). Dept. de Quimica], e-mail: anahjanuario@unifran.br; Silva, Jorge Jose de Brito; Conserva, Lucia Maria [Universidade Federal de Alagoas (UFAL), Maceio, AL (Brazil). Inst. de Quimica e Biotecnologia

2009-07-01

The chemical composition of two specimens of Esenbeckia grandiflora, collected in the south and northeast regions of Brazil, was investigated. In this study, three b-indolopyridoquinazoline alkaloids from the leaves (rutaecarpine, 1-hydroxyrutaecarpine) and roots (euxylophoricine D) were isolated for the first time in this genus. In addition, the triterpenes {alpha}-amyrin, {beta}-amyrin, {alpha}-amyrenonol, {beta}-amyrenonol, 3{alpha}-hydroxy-ursan-12-one, and 3{alpha}-hydroxy-12,13-epoxy-oleanane, the coumarins auraptene, umbelliferone, pimpinelin, and xanthotoxin, the furoquinoline alkaloids delbine and kokusaginine, and the phytosteroids sitosterol, stigmasterol, campesterol and 3{beta}-O-{beta}-D-glucopyranosylsitosterol were also isolated from the leaves, twigs, roots and stems of this species. Structures of these compounds were established by spectral analysis. (author)

Analysis of E. rutaecarpa Alkaloids Constituents In Vitro and In Vivo by UPLC-Q-TOF-MS Combined with Diagnostic Fragment

Directory of Open Access Journals (Sweden)

Shenshen Yang

2016-01-01

Full Text Available Evodia rutaecarpa (Juss. Benth. (Rutaceae dried ripe fruit is used for dispelling colds, soothing liver, and analgesia. Pharmacological research has proved that alkaloids are the main active ingredients of E. rutaecarpa. This study aimed to rapidly classify and identify the alkaloids constituents of E. rutaecarpa by using UPLC-Q-TOF-MS coupled with diagnostic fragments. Furthermore, the effects of the material base of E. rutaecarpa bioactive ingredients in vivo were examined such that the transitional components in the blood of rats intragastrically given E. rutaecarpa were analyzed and identified. In this study, the type of alcohol extraction of E. rutaecarpa and the corresponding blood sample were used for the analysis by UPLC-Q-TOF-MS in positive ion mode. After reviewing much of the literature and collected information on the fragments, we obtained some diagnostic fragments of the alkaloids. Combining the diagnostic fragments with the technology of UPLC-Q-TOF-MS, we identified the compounds of E. rutaecarpa and blood samples and compared the ion fragment information with that of the alkaloids in E. rutaecarpa. A total of 17 alkaloids components and 6 blood components were identified. The proposed method was rapid, accurate, and sensitive. Therefore, this technique can reliably and practically analyze the chemical constituents in traditional Chinese medicine (TCM.

Currencies of Mutualisms: Sources of Alkaloid Genes in Vertically Transmitted Epichloae

Directory of Open Access Journals (Sweden)

Christopher L. Schardl

2013-06-01

Full Text Available The epichloae (Epichloë and Neotyphodium species, a monophyletic group of fungi in the family Clavicipitaceae, are systemic symbionts of cool-season grasses (Poaceae subfamily Poöideae. Most epichloae are vertically transmitted in seeds (endophytes, and most produce alkaloids that attack nervous systems of potential herbivores. These protective metabolites include ergot alkaloids and indole-diterpenes (tremorgens, which are active in vertebrate systems, and lolines and peramine, which are more specific against invertebrates. Several Epichloë species have been described which are sexual and capable of horizontal transmission, and most are vertically transmissible also. Asexual epichloae are mainly or exclusively vertically transmitted, and many are interspecific hybrids with genomic contributions from two or three ancestral Epichloë species. Here we employ genome-scale analyses to investigate the origins of biosynthesis gene clusters for ergot alkaloids (EAS, indole-diterpenes (IDT, and lolines (LOL in 12 hybrid species. In each hybrid, the alkaloid-gene and housekeeping-gene relationships were congruent. Interestingly, hybrids frequently had alkaloid clusters that were rare in their sexual ancestors. Also, in those hybrids that had multiple EAS, IDT or LOL clusters, one cluster lacked some genes, usually for late pathway steps. Possible implications of these findings for the alkaloid profiles and endophyte ecology are discussed.

Currencies of Mutualisms: Sources of Alkaloid Genes in Vertically Transmitted Epichloae

Science.gov (United States)

Schardl, Christopher L.; Young, Carolyn A.; Pan, Juan; Florea, Simona; Takach, Johanna E.; Panaccione, Daniel G.; Farman, Mark L.; Webb, Jennifer S.; Jaromczyk, Jolanta; Charlton, Nikki D.; Nagabhyru, Padmaja; Chen, Li; Shi, Chong; Leuchtmann, Adrian

2013-01-01

The epichloae (Epichloë and Neotyphodium species), a monophyletic group of fungi in the family Clavicipitaceae, are systemic symbionts of cool-season grasses (Poaceae subfamily Poöideae). Most epichloae are vertically transmitted in seeds (endophytes), and most produce alkaloids that attack nervous systems of potential herbivores. These protective metabolites include ergot alkaloids and indole-diterpenes (tremorgens), which are active in vertebrate systems, and lolines and peramine, which are more specific against invertebrates. Several Epichloë species have been described which are sexual and capable of horizontal transmission, and most are vertically transmissible also. Asexual epichloae are mainly or exclusively vertically transmitted, and many are interspecific hybrids with genomic contributions from two or three ancestral Epichloë species. Here we employ genome-scale analyses to investigate the origins of biosynthesis gene clusters for ergot alkaloids (EAS), indole-diterpenes (IDT), and lolines (LOL) in 12 hybrid species. In each hybrid, the alkaloid-gene and housekeeping-gene relationships were congruent. Interestingly, hybrids frequently had alkaloid clusters that were rare in their sexual ancestors. Also, in those hybrids that had multiple EAS, IDT or LOL clusters, one cluster lacked some genes, usually for late pathway steps. Possible implications of these findings for the alkaloid profiles and endophyte ecology are discussed. PMID:23744053

Currencies of mutualisms: sources of alkaloid genes in vertically transmitted epichloae.

Science.gov (United States)

Schardl, Christopher L; Young, Carolyn A; Pan, Juan; Florea, Simona; Takach, Johanna E; Panaccione, Daniel G; Farman, Mark L; Webb, Jennifer S; Jaromczyk, Jolanta; Charlton, Nikki D; Nagabhyru, Padmaja; Chen, Li; Shi, Chong; Leuchtmann, Adrian

2013-06-06

The epichloae (Epichloë and Neotyphodium species), a monophyletic group of fungi in the family Clavicipitaceae, are systemic symbionts of cool-season grasses (Poaceae subfamily Poöideae). Most epichloae are vertically transmitted in seeds (endophytes), and most produce alkaloids that attack nervous systems of potential herbivores. These protective metabolites include ergot alkaloids and indole-diterpenes (tremorgens), which are active in vertebrate systems, and lolines and peramine, which are more specific against invertebrates. Several Epichloë species have been described which are sexual and capable of horizontal transmission, and most are vertically transmissible also. Asexual epichloae are mainly or exclusively vertically transmitted, and many are interspecific hybrids with genomic contributions from two or three ancestral Epichloë species. Here we employ genome-scale analyses to investigate the origins of biosynthesis gene clusters for ergot alkaloids (EAS), indole-diterpenes (IDT), and lolines (LOL) in 12 hybrid species. In each hybrid, the alkaloid-gene and housekeeping-gene relationships were congruent. Interestingly, hybrids frequently had alkaloid clusters that were rare in their sexual ancestors. Also, in those hybrids that had multiple EAS, IDT or LOL clusters, one cluster lacked some genes, usually for late pathway steps. Possible implications of these findings for the alkaloid profiles and endophyte ecology are discussed.

Enantioselective Copper-Catalyzed Carboetherification of Unactivated Alkenes**

Science.gov (United States)

Bovino, Michael T.; Liwosz, Timothy W.; Kendel, Nicole E.; Miller, Yan; Tyminska, Nina

2014-01-01

Chiral saturated oxygen heterocycles are important components of bioactive compounds. Cyclization of alcohols onto pendant alkenes is a direct route to their synthesis, but few catalytic enantioselective methods enabling cyclization onto unactivated alkenes exist. Herein is reported a highly efficient copper-catalyzed cyclization of γ-unsaturated pentenols that terminates in C-C bond formation, a net alkene carboetherification. Both intra- and intermolecular C-C bond formations are demonstrated, yielding functionalized chiral tetrahydrofurans as well as fused-ring and bridged-ring oxabicyclic products. Transition state calculations support a cis-oxycupration stereochemistry-determining step. PMID:24798697

Therapeutic effects of Sophora moorcroftiana alkaloids in combination with albendazole in mice experimentally infected with protoscolices of Echinococcus granulosus

Directory of Open Access Journals (Sweden)

X.M. Ma

2007-10-01

Full Text Available The objective of the present study was to determine if the combination of alkaloids from Sophora moorcroftiana seeds and albendazole might be effective in the treatment of experimental echinococcosisin female NIH mice (6 weeks old and weighing 18-20 g, N = 8 in each group infected withprotoscolices of Echinococcus granulosus. Viable protoscolices (N = 6 x 103 were cultured in vitro in 1640 medium and mortality was calculated daily. To determine the in vivo efficacy, mice were inoculated intraperitoneally with viable protoscolices and then treated once daily by gavage for three months with the alkaloids (50 mg kg-1 day-1 and albendazole (50 mg kg-1 day-1, separately and in combination (both alkaloids at 25 mg kg-1 day-1 and albendazole at 25 mg kg-1 day-1. Next, the hydatid cysts collected from the peritoneal cavity of the animals were weighed and serum IL-4, IL-2, and IgE levels were analyzed. Administration of alkaloids to cultured protoscolices showed significant dose- and time-dependent killing effects. The weight of hydatid cysts was significantly decreased upon treatment with each drug (P < 0.01, but the decrease was more prominent and the rate of hydatid cyst growth inhibition was much higher (76.1% in the group receiving the combined treatments (18.3 ± 4.6 mg. IL-4 and total IgE were decreased (939 ± 447 pg/mL and 2.03 ± 0.42 IU/mL, respectively in serum from mice treated with alkaloids and albendazole compared with the untreated control (1481 ± 619 pg/mL and 3.31 ± 0.37 IU/mL; P < 0.01. These results indicate that S. moorcroftiana alkaloids have protoscolicidal effects and the combination of alkaloids and albendazole has significant additive effects.

Enantioselective Characteristics and Montmorillonite-Mediated Removal Effects of α-Hexachlorocyclohexane in Laying Hens.

Science.gov (United States)

Liu, Xueke; Shen, Zhigang; Wang, Peng; Liu, Chang; Yao, Guojun; Zhou, Zhiqiang; Liu, Donghui

2016-06-07

α-Hexachlorocyclohexane (α-HCH) is a chiral organochlorine pesticide that is often ubiquitously detected in various environmental matrices and may be absorbed by the human body via food consumption, with serious detriments to human health. In this study, enantioselective degradation kinetics and residues of α-HCH in laying hens were investigated after a single dose of exposure to the pesticide, whereas enantioselectivity and residues of α-HCH in eggs, droppings, and various tissues were investigated after long-term exposure. Meanwhile, montmorillonite (MMT), a feed additive with high capacity of adsorption, was investigated for its ability to remove α-HCH from laying hens. Most non-brain tissues enantioselectively accumulated (-)-α-HCH, while (+)-α-HCH was preferentially accumulated in the brain. The enantiomer fractions (EFs) in most tissues gradually decreased, implying continuous depletion of (+)-α-HCH in laying hens. After 30 days of exposure and 31 days of elimination, the concentration of α-HCH in eggs and tissues of laying hens with MMT-containing feed was lower than that with MMT-free feed, indicating the removal effects of MMT for α-HCH in laying hens. The findings presented herein suggest that modified MMT may potentially be useful in reducing the enrichment of α-HCH in laying hens and eggs, thus lowering the risk of human intake of α-HCH.

Enhancing the potential of enantioselective organocatalysis with light

Science.gov (United States)

Silvi, Mattia; Melchiorre, Paolo

2018-02-01

Organocatalysis—catalysis mediated by small chiral organic molecules—is a powerful technology for enantioselective synthesis, and has extensive applications in traditional ionic, two-electron-pair reactivity domains. Recently, organocatalysis has been successfully combined with photochemical reactivity to unlock previously inaccessible reaction pathways, thereby creating new synthetic opportunities. Here we describe the historical context, scientific reasoning and landmark discoveries that were essential in expanding the functions of organocatalysis to include one-electron-mediated chemistry and excited-state reactivity.

Synthesis of Lycodine-Type Lycopodium Alkaloids Using C-H Functionalization Tactics

OpenAIRE

Newton, James

2015-01-01

This dissertation describes our syntheses of several lycodine-type Lycopodium alkaloids by the late-stage C-H functionalization of lycodine derivatives. Lycodine-type alkaloids are well-known for their neurological activity. For example, huperzine A is a potent acetylcholinesterase inhibitor and the complanadine family of molecules has been shown to induce the secretion of Nerve Growth Factor. Due to these properties, lycodine-type alkaloids serve as interesting lead compounds for the deve...

Improvement of enantioselectivity by immobilized imprinting of epoxide hydrolase from Rhodotorula glutinis

NARCIS (Netherlands)

Kronenburg, N.A.E.; Bont, de J.A.M.; Fischer, L.

2001-01-01

The yeast Rhodotorula glutinis contains an enantioselective, membrane-associated epoxide hydrolase (EH). Partially purified EH was immobilized in a two-step procedure. In the first step, the proteins were derivatized with itaconic anhydride. In the second step, the derivatized proteins were

The Enantioselectivity of Odor Sensation: Some Examples for Undergraduate Chemistry Courses

Science.gov (United States)

Kraft, Philip; Mannschreck, Albrecht

2010-01-01

This article discusses seven chiral odorants that demonstrate the enantioselectivity of odor sensation: carvone, Celery Ketone, camphor, Florhydral, 3-methyl-3-sulfanylhexan-1-ol, muscone, and methyl jasmonate. After a general introduction of the odorant-receptor interaction and the combinatorial code of olfaction, the olfactory properties of the…

The role of the achiral template in enantioselective transformations. Radical conjugate additions to alpha-methacrylates followed by hydrogen atom transfer.

Science.gov (United States)

Sibi, Mukund P; Sausker, Justin B

2002-02-13

We have evaluated various achiral templates (1a-g, 10, and 16) in conjunction with chiral Lewis acids in the conjugate addition of nucleophilic radicals to alpha-methacrylates followed by enantioselective H-atom transfer. Of these, a novel naphthosultam template (10) gave high enantioselectivity in the H-atom-transfer reactions with ee's up to 90%. A chiral Lewis acid derived from MgBr(2) and bisoxazoline (2) gave the highest selectivity in the enantioselective hydrogen-atom-transfer reactions. Non-C(2) symmetric oxazolines (20-25) have also been examined as ligands, and of these, compound 25 gave optimal results (87% yield and 80% ee). Insights into rotamer control in alpha-substituted acrylates and the critical role of the tetrahedral sulfone moiety in realizing high selectivity are discussed.

Manzamine alkaloids: isolation, cytotoxicity, antimalarial activity and SAR studies.

Science.gov (United States)

Ashok, Penta; Ganguly, Swastika; Murugesan, Sankaranarayanan

2014-11-01

The infectious disease Malaria is caused by different species of the genus Plasmodium. Resistance to quinoline antimalarial drugs and decreased susceptibility to artemisinin-based combination therapy have increased the need for novel antimalarial agents. Historically, natural products have been used for the treatment of infectious diseases. Identification of natural products and their semi-synthetic derivatives with potent antimalarial activity is an important method for developing novel antimalarial agents. Manzamine alkaloids are a unique group of β-carboline alkaloids isolated from various species of marine sponge displaying potent antimalarial activity against drug-sensitive and -resistant strains of Plasmodium. In this review, we demonstrate antimalarial potency, cytotoxicity and antimalarial SAR of manzamine alkaloids. Copyright © 2014 Elsevier Ltd. All rights reserved.

Enantioselective small molecule synthesis by carbon dioxide fixation using a dual Brønsted acid/base organocatalyst.

Science.gov (United States)

Vara, Brandon A; Struble, Thomas J; Wang, Weiwei; Dobish, Mark C; Johnston, Jeffrey N

2015-06-17

Carbon dioxide exhibits many of the qualities of an ideal reagent: it is nontoxic, plentiful, and inexpensive. Unlike other gaseous reagents, however, it has found limited use in enantioselective synthesis. Moreover, unprecedented is a tool that merges one of the simplest biological approaches to catalysis-Brønsted acid/base activation-with this abundant reagent. We describe a metal-free small molecule catalyst that achieves the three component reaction between a homoallylic alcohol, carbon dioxide, and an electrophilic source of iodine. Cyclic carbonates are formed enantioselectively.

Regio-, Diastereo-, and Enantioselective Nitroso-Diels-Alder Reaction of 1,3-Diene-1-carbamates Catalyzed by Chiral Phosphoric Acids.

Science.gov (United States)

Pous, Jonathan; Courant, Thibaut; Bernadat, Guillaume; Iorga, Bogdan I; Blanchard, Florent; Masson, Géraldine

2015-09-23

Chiral phosphoric acid-catalyzed asymmetric nitroso-Diels-Alder reaction of nitrosoarenes with carbamate-dienes afforded cis-3,6-disubstituted dihydro-1,2-oxazines in high yields with excellent regio-, diastereo-, and enantioselectivities. Interestingly, we observed that the catalyst is able not only to control the enantioselectivity but also to reverse the regioselectivity of the noncatalyzed nitroso-Diels-Alder reaction. The regiochemistry reversal and asynchronous concerted mechanism were confirmed by DFT calculations.

Enantioselective organocatalyzed Oxa-Michael-Aldol cascade reactions: Construction of chiral 4H-chromenes with a trifluoromethylated tetrasubstituted carbon stereocenter

KAUST Repository

Zhang, Jing

2015-03-13

The first organocatalytic asymmetric synthesis of 4H-chromenes bearing a trifluoromethylated tetrasubstituted carbon center is presented. Chiral secondary amines promote the oxa-Michael-aldol cascade reaction between alkynals and 2-trifluoroacetylphenols via iminium-allenamine activation to produce pharmaceutically important heterocycles with excellent enantioselectivities. The proposed reaction can be scaled-up easily with maintenance of the excellent enantioselectivity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of benzylisoquinoline alkaloids on the larvae of polyphagous Lepidoptera.

Science.gov (United States)

Miller, James S; Feeny, Paul

1983-06-01

Six benzylisoquinoline alkaloids were fed to the larvae of three polyphagous Lepidoptera species: Hyphantria cunea, Spodoptera eridania, and Lymantria dispar. Exposure of last instar larvae to alkaloid-containing diets over a 24-h period resulted in reduced feeding rates and reduced growth efficiencies. Lymantria dispar larvae reared from eggs on alkaloid diets took longer to reach the fifth instar, attained lower larval weights, and showed reduced survivorship. The benzylisoquinolines tested were not equally effective as toxins or feeding inhibitors. Some produced dramatic effects while others produced no effects. The relative responses of the three caterpillar species to the six alkaloids were similar. Those benzylisoquinolines with a methylene-dioxyphenyl (1,3-benzodioxole) group were consistently the most toxic or repellent while laudanosine, a relatively simple benzylisoquinoline, was generally innocuous. Available host records indicate that benzylisoquinoline-containing plants are avoided by the larvae of these moth species.

Australine, a pyrrolizidine alkaloid that inhibits amyloglucosidase and glycoprotein processing

International Nuclear Information System (INIS)

Tropea, J.E.; Molyneux, R.J.; Kaushal, G.P.; Pan, Y.T.; Mitchell, M.; Elbein, A.D.

1989-01-01

Australine is a polyhydroxylated pyrrolizidine alkaloid that was isolated from the seeds of the Australian tree Castanospermum australe and characterized by NMR and X-ray diffraction analysis. Since swainsonine and catanospermine are polyhydroxylated indolizidine alkaloids that inhibit specific glycosidases, the authors tested australine against a variety of exoglycosidases to determine whether it would inhibit any of these enzymes. This alkaloid proved to be a good inhibitor of the α-glucosidase amyloglucosidase (50% inhibition at 5.8 μM), but it did not inhibit β-glucosidase, α- or β-mannosidase, or α- or β-galactosidase. The inhibition of amyloglucosidase was of a competitive nature. Australine also inhibited the glycoprotein processing enzyme glucosidase I, but had only slight activity toward glucosidase II. When incubated with cultured cells, this alkaloid inhibited glycoprotein processing at the glucosidase I step and caused the accumulation of glycoproteins with Glc 3 Man 7-9 (GlcNAc) 2 -oligosaccharides

Indole alkaloids from leaves and twigs of Rauvolfia verticillata.

Science.gov (United States)

Zhang, Bing-Jie; Peng, Lei; Wu, Zhi-Kun; Bao, Mei-Fen; Liu, Ya-Ping; Cheng, Gui-Guang; Luo, Xiao-Dong; Cai, Xiang-Hai

2013-01-01

Seven new indole alkaloids, rauverines A-G (1-7), and 19 known indole alkaloids were isolated from the leaves and twigs of Rauvolfia verticillata. All compounds showed no cytotoxicity against five human cancer cell lines, human myeloid leukemia (HL-60), hepatocellular carcinoma (SMMC-7721), lung cancer (A-549), breast cancer (MCF-7), and colon cancer (SW480) cells.

Pyrrolizidine alkaloids from Bulgarian species of the genus Senecio

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NADEZHDA KOSTOVA

2006-12-01

Full Text Available Nine Bulgarian species from the genus Senecio were studied phytochemically and/or by GC-MS analysis. Senecivernine-N-oxide was isolated and identified by spectral data for the first time. Different types of pyrrolizidine alkaloids were tested for cytotoxicity on murine lymphocytes. At a concentration of 100 µg/ml, the alkaloid retroisosenine showed immunosuppressive effect.

Sequestered Alkaloid Defenses in the Dendrobatid Poison Frog Oophaga pumilio Provide Variable Protection from Microbial Pathogens.

Science.gov (United States)

Hovey, Kyle J; Seiter, Emily M; Johnson, Erin E; Saporito, Ralph A

2018-03-01

Most amphibians produce their own defensive chemicals; however, poison frogs sequester their alkaloid-based defenses from dietary arthropods. Alkaloids function as a defense against predators, and certain types appear to inhibit microbial growth. Alkaloid defenses vary considerably among populations of poison frogs, reflecting geographic differences in availability of dietary arthropods. Consequently, environmentally driven differences in frog defenses may have significant implications regarding their protection against pathogens. While natural alkaloid mixtures in dendrobatid poison frogs have recently been shown to inhibit growth of non-pathogenic microbes, no studies have examined the effectiveness of alkaloids against microbes that infect these frogs. Herein, we examined how alkaloid defenses in the dendrobatid poison frog, Oophaga pumilio, affect growth of the known anuran pathogens Aeromonas hydrophila and Klebsiella pneumoniae. Frogs were collected from five locations throughout Costa Rica that are known to vary in their alkaloid profiles. Alkaloids were isolated from individual skins, and extracts were assayed against both pathogens. Microbe subcultures were inoculated with extracted alkaloids to create dose-response curves. Subsequent spectrophotometry and cell counting assays were used to assess growth inhibition. GC-MS was used to characterize and quantify alkaloids in frog extracts, and our results suggest that variation in alkaloid defenses lead to differences in inhibition of these pathogens. The present study provides the first evidence that alkaloid variation in a dendrobatid poison frog is associated with differences in inhibition of anuran pathogens, and offers further support that alkaloid defenses in poison frogs confer protection against both pathogens and predators.

Purification and characterisation of a novel enantioselective epoxide hydrolase from Aspergillus niger M200

Czech Academy of Sciences Publication Activity Database

Kotík, Michael; Kyslík, Pavel

2006-01-01

Roč. 1760, - (2006), s. 245-252 ISSN 0006-3002 Institutional research plan: CEZ:AV0Z50200510 Keywords : epoxide hydrolase * enantioselectivity * aspergillus niger Subject RIV: EE - Microbiology, Virology

Combining the catalytic enantioselective reaction of visible-light-generated radicals with a by-product utilization system.

Science.gov (United States)

Huang, Xiaoqiang; Luo, Shipeng; Burghaus, Olaf; Webster, Richard D; Harms, Klaus; Meggers, Eric

2017-10-01

We report an unusual reaction design in which a chiral bis-cyclometalated rhodium(iii) complex enables the stereocontrolled chemistry of photo-generated carbon-centered radicals and at the same time catalyzes an enantioselective sulfonyl radical addition to an alkene. Specifically, employing inexpensive and readily available Hantzsch esters as the photoredox mediator, Rh-coordinated prochiral radicals generated by a selective photoinduced single electron reduction are trapped by allyl sulfones in a highly stereocontrolled fashion, providing radical allylation products with up to 97% ee. The hereby formed fragmented sulfonyl radicals are utilized via an enantioselective radical addition to form chiral sulfones, which minimizes waste generation.

Diversity of Pyrrolizidine Alkaloids in the Boraginaceae Structures, Distribution, and Biological Properties

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Assem El-Shazly

2014-04-01

Full Text Available Among the diversity of secondary metabolites which are produced by plants as means of defence against herbivores and microbes, pyrrolizidine alkaloids (PAs are common in Boraginaceae, Asteraceae and some other plant families. Pyrrolizidine alkaloids are infamous as toxic compounds which can alkylate DNA und thus cause mutations and even cancer in herbivores and humans. Almost all genera of the family Boraginaceae synthesize and store this type of alkaloids. This review reports the available information on the present status (literature up to early 2014 of the pyrrolizidine alkaloids in the Boraginaceae and summarizes the topics structure, distribution, chemistry, chemotaxonomic significance, and biological properties.

Semiquantitative determination of ergot alkaloids in seed, straw, and digesta samples using a competitive enzyme-linked immunosorbent assay.

Science.gov (United States)

Schnitzius, J M; Hill, N S; Thompson, C S; Craig, A M

2001-05-01

Ergot alkaloids present in endophyte-infected (E+) tall fescue cause fescue toxicosis and other toxic effects in livestock that consume infected plant tissue, leading to significant financial losses in livestock production each year. The predominant method currently in use for quantifying ergot alkaloid content in plant tissue is through high-performance liquid chromatography (HPLC), which quantifies the amount of ergovaline, one of many ergot alkaloids in E+ plant tissue. The enzyme-linked immunosorbent assay (ELISA) method used in this study detects quantities of nonspecific ergot alkaloids and therefore accounts for greater amounts of the total ergot alkaloid content in E+ tissue than does HPLC. The ELISA can also be used to more expediently analyze a larger number of forage samples without sophisticated and costly analytical equipment and therefore could be more desirable in a diagnostic setting. The purpose of this study was to evaluate the between-day and within-run variability of the ELISA and to determine the binding efficiency of 6 ergot alkaloids to the 15F3.E5 antibody used in the competitive ELISA to ascertain its feasibility as a quick analysis tool for ergot alkaloids. Straw samples had an average coefficient of variation (CV) for concentration of 10.2% within runs and 18.4% between runs, and the seed samples had an average CV for concentration of 13.3% within runs and 24.5% between runs. The grass tissue-based lysergic acid standard curve calculated from the ELISA had an average r2 of 0.99, with a CV of 2.1%. Ergocryptine, ergocristine, ergocornine, and ergotamine tartrate did not bind strongly to the 15F3.E5 antibody because of the presence of large side groups on these molecules, which block their binding to the antibody, whereas ergonovine and ergonovine maleate were bound much more efficiently because of their structural similarity to lysergic acid. Clarified rumen fluid was tested as an additional matrix for use in the ergot alkaloid competitive

Distinct sesquiterpene pyridine alkaloids from in Salvadoran and Peruvian Celastraceae species.

Science.gov (United States)

Callies, Oliver; Núñez, Marvin J; Perestelo, Nayra R; Reyes, Carolina P; Torres-Romero, David; Jiménez, Ignacio A; Bazzocchi, Isabel L

2017-10-01

As part of a bioprospecting program aimed at the discovery of undescribed natural products from Salvadoran and Peruvian flora, the phytochemical investigations of four Celastraceae species, Celastrus vulcanicola, Maytenus segoviarum, Maytenus jeslkii, and Maytenus cuzcoina, were performed. The current study reports the isolation and structural characterization of five previously undescribed macrolide sesquiterpene pyridine alkaloids, named vulcanicoline-A, cuzcoinine, vulcanicoline-B, jelskiine, and vulcanicoline-C, along with sixteen known alkaloids. The structures of the alkaloids were established by spectrometric and extensive 1D and 2D NMR spectroscopic analysis, including COSY, HSQC, HMBC, and ROESY experiments. The absolute configurations of alkaloids were proposed based on optical rotation sign, and biogenetic considerations. This study represents the first phytochemical analysis of Maytenus segoviarum. Copyright © 2017 Elsevier Ltd. All rights reserved.

Carry-over of pyrrolizidine alkaloids from feed to milk in dairy cows.

Science.gov (United States)

Hoogenboom, L A P; Mulder, P P J; Zeilmaker, M J; van den Top, H J; Remmelink, G J; Brandon, E F A; Klijnstra, M; Meijer, G A L; Schothorst, R; Van Egmond, H P

2011-03-01

Pyrrolizidine alkaloids are toxins present in many plants belonging to the families of Asteraceae, Boraginaceae and Fabaceae. Particularly notorious are pyrrolizidine alkaloids present in ragwort species (Senecio), which are held responsible for hepatic disease in horses and cows and may lead to the death of the affected animals. In addition, these compounds may be transferred to edible products of animal origin and as such be a threat for the health of consumers. To investigate the possible transfer of pyrrolizidine alkaloids from contaminated feed to milk, cows were put on a ration for 3 weeks with increasing amounts (50-200 g day(-1)) of dried ragwort. Milk was collected and sampled twice a day; faeces and urine twice a week. For milk, a dose-related appearance of pyrrolizidine alkaloids was found. Jacoline was the major component in milk despite being a minor component in the ragwort material. Practically no N-oxides were observed in milk, notwithstanding the fact that they constituted over 80% of the pyrrolizidine alkaloids in ragwort. The overall carry-over of the pyrrolizidine alkaloids was estimated to be only around 0.1%, but for jacoline 4%. Notwithstanding the low overall carry-over, this may be relevant for consumer health considering the genotoxic and carcinogenic properties demonstrated for some of these compounds. Analysis of the faeces and urine samples indicated that substantial metabolism of pyrrolizidine alkaloids is taking place. The toxicity and potential transfer of metabolites to milk is unknown and remains to be investigated.

Australine, a pyrrolizidine alkaloid that inhibits amyloglucosidase and glycoprotein processing

Energy Technology Data Exchange (ETDEWEB)

Tropea, J.E.; Molyneux, R.J.; Kaushal, G.P.; Pan, Y.T.; Mitchell, M.; Elbein, A.D. (Univ. of Texas Health Science Center, San Antonio (USA))

1989-03-07

Australine is a polyhydroxylated pyrrolizidine alkaloid that was isolated from the seeds of the Australian tree Castanospermum australe and characterized by NMR and X-ray diffraction analysis. Since swainsonine and catanospermine are polyhydroxylated indolizidine alkaloids that inhibit specific glycosidases, the authors tested australine against a variety of exoglycosidases to determine whether it would inhibit any of these enzymes. This alkaloid proved to be a good inhibitor of the {alpha}-glucosidase amyloglucosidase (50% inhibition at 5.8 {mu}M), but it did not inhibit {beta}-glucosidase, {alpha}- or {beta}-mannosidase, or {alpha}- or {beta}-galactosidase. The inhibition of amyloglucosidase was of a competitive nature. Australine also inhibited the glycoprotein processing enzyme glucosidase I, but had only slight activity toward glucosidase II. When incubated with cultured cells, this alkaloid inhibited glycoprotein processing at the glucosidase I step and caused the accumulation of glycoproteins with Glc{sub 3}Man{sub 7-9}(GlcNAc){sub 2}-oligosaccharides.

Determination of pyrrolizidine alkaloids in commercial comfrey products (Symphytum sp.).

Science.gov (United States)

Betz, J M; Eppley, R M; Taylor, W C; Andrzejewski, D

1994-05-01

The presence of hepatotoxic pyrrolizidine alkaloids in comfrey (Symphytum sp.) and the widespread use of decoctions of this plant as a beverage (herbal tea) are of increasing concern. A method for the extraction and solid-phase concentration and capillary gas chromatographic determination of these alkaloids and their N-oxides in botanical materials has been developed and was applied to eleven comfrey-containing products purchased from retail health-food outlets in the Washington, DC, area during May-June 1989. Nine of the 11 products were found to contain measurable quantities of one or more of the alkaloids, in ranges from 0.1 to 400.0 ppm. Products containing comfrey leaf in combination with one or more other ingredients were found to contain the lowest alkaloid levels. Highest levels were found in bulk comfrey root, followed by bulk comfrey leaf. The species of the bulk material was verified by thin-layer chromatography and other means.

POSSIBILITY FOR APPLICATION OF LIQUEFIED GASES FOR PURIFICATION OF BARBERRY ALKALOIDS

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Demyanenko D.V.

2016-06-01

Full Text Available Introduction. Biologically active substances (BAS of barberry roots represented by alkaloids of isoquinoline group are perspective substances for development of preparations with multiple pharmacological activities. However, now manufacture of them in Ukraine is stopped. One of the reasons of this is out-of-date production technologies of alkaloids involving use of toxic and/or flammable solvents. In the article possibility for application of liquefied gases in technology of obtaining of alkaloids from barberry roots has been studied. Materials and methods. Initial raw herb drug were barberry (Berberis vulgaris roots harvested in spring on the territory of Southern Ukraine. Their moisture content was 11%, comminuting degree was 0,5-1,4 mm. At the first stage purification of raw herb drug from lipophilic impurities (defatting was made with use of some liquefied gases: tetrafluoroethane, isobutane, difluorochloromethane and difluoromethane. Extraction of the alkaloid sum was made with difluoromethane mixed with various quantities of liquid ammonia or diethylamine as alkaline agent. Crude extracts were exposed to two-level liquefied-gas purification. At first the alkaloid bases were transformed into saline forms with aqueous solutions of acids and purified from ballast impurities with liquefied freon-22. Then alkaloid salts were reextracted from aqueous phase in the base form with liquefied mixture of difluoromethane and ammonia. Mixing of liquid phases was provided by creation of alternate gradients of temperatures and, as consequence, pressures between separators feeding alternately cool water into jacket of one of them, and warm water – into jacket of another one. Quantity of lipophilic ballast impurities and also weight of extractives were determined gravimetrically. Quantitative analysis of the alkaloid sum was made by titrimetric method after sedimentation of alkaloids with volumetric solution of phosphomolybdic acid. Results and discussion

Drug development against tuberculosis: Impact of alkaloids.

Science.gov (United States)

Mishra, Shardendu K; Tripathi, Garima; Kishore, Navneet; Singh, Rakesh K; Singh, Archana; Tiwari, Vinod K

2017-09-08

Despite of the advances made in the treatment and management, tuberculosis (TB) still remains one of main public health problem. The contrary effects of first and second-line anti-tuberculosis drugs have generated extended research interest in natural products in the hope of devising new antitubercular leads. Interestingly, plethoras of natural products have been discovered to exhibit activity towards various resistant strains of M. tuberculosis. Extensive applications of alkaloids in the field of therapeutics is well-established and nowday's researches being pursued to develop new potent drugs from natural sources for tuberculosis. Alkaloids are categorized in quite a few groups according to their structures and isolation from both terrestrial and marine sources. These new drugs might be a watershed in the battle against tuberculosis. This review summarizes alkaloids, which were found active against Mycobacteria since last ten years with special attention on the study of structure-activity relationship (SAR) and mode of action with their impact in drug discovery and development against tuberculosis. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Analysis of herbal teas made from the leaves of comfrey (Symphytum officinale): reduction of N-oxides results in order of magnitude increases in the measurable concentration of pyrrolizidine alkaloids.

Science.gov (United States)

Oberlies, Nicholas H; Kim, Nam-Cheol; Brine, Dolores R; Collins, Bradley J; Handy, Robert W; Sparacino, Charles M; Wani, Mansukh C; Wall, Monroe E

2004-10-01

To determine the relative quantities of two hepatotoxic pyrrolizidine alkaloids, symphytine and echimidine, in teas prepared from comfrey leaves (Symphytum officinale), and to determine the potential contribution of the N-oxide forms of these alkaloids to levels of the parent alkaloids. Comfrey leaves were purchased from three commercial sources and used to prepare tea in a manner consistent with the methods used by consumers. An extraction scheme was devised for extraction of the alkaloids, and a gas chromatographic method was developed to quantify the two major alkaloids, symphytine and echimidine. Recognising that the N-oxide derivatives of these alkaloids have also been identified in comfrey preparations, chemical reduction was applied to determine the total quantities of the alkaloids as free bases and as N-oxide derivatives. The concentration of symphytine and echimidine varied considerably between teas prepared from leaves purchased from the different vendors of plant material. Moreover, a much higher concentration of symphytine was found in the tea when steps were included to reduce N-oxides prior to analysis. The treatment of pure symphytine with hot water did not generate the N-oxide derivative de novo. Since the pyrrolizidine alkaloids are known to be hepatotoxic, consumption of herbal teas made from comfrey leaves may be ill-advised. The concentration of pyrrolizidine alkaloids in such teas may be underestimated substantially unless the concentration of N-oxides is taken into consideration.

Enantioselective skin permeation of ibuprofen enantiomers: mechanistic insights from ATR-FTIR and CLSM studies based on synthetic enantiomers as naphthalimide fluorescent probes.

Science.gov (United States)

Che, Qi-en; Quan, Peng; Mu, Mao; Zhang, Xinfu; Zhao, Hanqing; Zhang, Yu; You, Song; Xiao, Yi; Fang, Liang

2014-10-01

The aim of this study was to investigate the mechanisms of different skin permeability of ibuprofen racemate and enantiomers. The percutaneous permeation of ibuprofen racemate and enantiomers through rabbit normal skin and damaged skin (without stratum corneum [SC]) was investigated in vitro using side-by-side diffusion cells. With the melting temperature-membrane transport model, the flux ratio of enantiomer/racemate was calculated from their thermodynamic properties obtained by differential scanning calorimetry. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) study was performed to evaluate the interaction between the enantiomers and the SC. New fluorescent probes were designed and utilized in confocal laser scanning microscopy (CLSM) study for visualization of the enantioselective permeation of the enantiomers through the intact rabbit skin. The flux of (S)-ibuprofen through normal skin was significantly higher than that of (RS)-ibuprofen and (R)-ibuprofen (p skin, there was no significant difference (p > 0.05). The predicted flux ratio of (S)-ibuprofen/(RS)-ibuprofen (2.50) was in close agreement with the experimentally determined ratio (2.48). These results were supported by ATR-FTIR and CLSM studies that indicated that a chiral environment of the skin led to the enantioselective permeation of enantiomers. The chiral nature of the SC and the different physicochemical properties of the enantiomers should be taken into account in the assessment of different skin permeability of the racemate and enantiomers. The synthetic fluorescent probes used in this study could visualize the enantioselective permeation of the chiral compounds across the skin.

A DFT exploration of the enantioselective rearrangement of cyclohexene oxide to cyclohexenol

DEFF Research Database (Denmark)

Brandt, Peter; Norrby, Per-Ola; Andersson, Pher G.

2003-01-01

In this paper, we present computational results for the (1S,3R,4R)-3-(pyrrolidinyl)-methyl-2-azabicyclo[2.2.1]heptane mediated rearrangement of cyclohexene oxide. The results nicely explain the differences in enantioselectivities between catalytic and stoichiometric mode between different ligands...

Enantioselective total synthesis of (+)-brefeldin A and 7-epi-brefeldin A.

Science.gov (United States)

Wu, Yikang; Shen, Xin; Yang, Yong-Qing; Hu, Qi; Huang, Jia-Hui

2004-05-28

A convergent enantioselective route to brefeldin A (BFA) and 7-epi-BFA was developed. The key C-4/C-5 chiral centers were established by using chiral auxiliary induced intermolecular asymmetric aldolization in the presence of TiCl(4) and TMEDA. The results with the thiazolidinethione/TiCl(4) mediated intermolecular asymmetric aldolization added some new information about the scope and limitations to the existing knowledge of that type of reactions (which so far was essentially limited to the reactions with N-propionyl thiazolidinethiones). During the course a method for protecting the liable aldol hydroxyl groups by using inexpensive TBSCl in DMF with 2,6-lutidine as the base was developed to replace the otherwise unavoidable TBSOTf procedure. Due to the excessive steric hindrance, removal of the auxiliary was much more difficult than most literature cases. Cleavage of the oxazolidinone by reduction was almost impossible. The thiazolidinethione auxiliary was relatively easier to remove. However, several reactions reported for facile removal of thiazolidinethione auxiliaries in the literature still failed. Reductive removal of the thiazolidinethione auxiliary was most effectively realized with LiBH(4) in diethyl ether in the presence of 1 equiv of MeOH (a modification of a literature procedure for removal of oxazolidinone auxiliaries in less hindered substrates). Apart from the auxiliary removal, oxidation of the alcohol into aldehyde and the deprotection of the dithiolane protecting group were also rather difficult in the present context. A range of methods were screened before final solutions were found. The five-membered ring was constructed by employing an intramolecular Mukaiyama reaction after many attempts with the intramolecular aldolization under a variety of conditions failed. The rate of elimination of the alkoxyl to form the alpha,beta-double bond of the key intermediate cyclopentenone 49 with DBU was highly solvent dependent (very sluggish in CH(2)Cl(2

ALKALOIDS OF SOME EUROPEAN AND MACARONESIAN SEDOIDEAE AND SEMPERVIVOIDEAE (CRASSULACEAE)

NARCIS (Netherlands)

STEVENS, JF; THART, H; HENDRIKS, H; MALINGRE, TM

1992-01-01

Some 22 pyrrolidine and piperdine alkaloids were detected in the leafy parts of Sedum acre, S. aetnense, S. anglicum, S. brissemoreti, S. farinosum, S. fusiforme, S. lancerottense, S. melanantherum, and S. nudum. In addition to the alkaloids known from S. acre, 1-(2-pyrrolidyl)-propan-2-one and

Modelling substrate specificity and enantioselectivity for lipases and esterases by substrate-imprinted docking

Directory of Open Access Journals (Sweden)

Tyagi Sadhna

2009-06-01

Full Text Available Abstract Background Previously, ways to adapt docking programs that were developed for modelling inhibitor-receptor interaction have been explored. Two main issues were discussed. First, when trying to model catalysis a reaction intermediate of the substrate is expected to provide more valid information than the ground state of the substrate. Second, the incorporation of protein flexibility is essential for reliable predictions. Results Here we present a predictive and robust method to model substrate specificity and enantioselectivity of lipases and esterases that uses reaction intermediates and incorporates protein flexibility. Substrate-imprinted docking starts with covalent docking of reaction intermediates, followed by geometry optimisation of the resulting enzyme-substrate complex. After a second round of docking the same substrate into the geometry-optimised structures, productive poses are identified by geometric filter criteria and ranked by their docking scores. Substrate-imprinted docking was applied in order to model (i enantioselectivity of Candida antarctica lipase B and a W104A mutant, (ii enantioselectivity and substrate specificity of Candida rugosa lipase and Burkholderia cepacia lipase, and (iii substrate specificity of an acetyl- and a butyrylcholine esterase toward the substrates acetyl- and butyrylcholine. Conclusion The experimentally observed differences in selectivity and specificity of the enzymes were reproduced with an accuracy of 81%. The method was robust toward small differences in initial structures (different crystallisation conditions or a co-crystallised ligand, although large displacements of catalytic residues often resulted in substrate poses that did not pass the geometric filter criteria.

Prenylindole alkaloids from Raputia praetermissa (Rutaceae) and their chemosystematic significance

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Rosas, Lisandra V.; Veiga, Thiago Andre M.; Fernandes, Joao B.; Vieira, Paulo C.; Silva, M. Fatima das G.F. da, E-mail: dmfs@power.ufscar.b [Universidade Federal de Sao Carlos (DQ/UFSCar), SP (Brazil). Dept. de Quimica

2011-07-01

The dichloromethane extract from the stems of Raputia praetermissa afforded four new compounds, 4-deoxyraputindole C (1), raputimonoindole A-B (2, 3), and hexadecanyl 2-hydroxy- 4-methoxy-cinnamate (5), besides the alkaloids 5-(4-methoxymethylfuran-2-yl)-1H-indole (raputimonoindole C), furoquinolines maculosidine, robustine, evolitrine and dictamnine. The hexane extract yielded N-methyl-4-methoxyquinoline-2(1H)-one, skimmianine, cycloartenone, sitosterol, stigmasterol and sitostenone. The anthranilate alkaloid content indicates that the genus is strongly related to those included in Cusparieae tribe, but differs from Neoraputia by the absence of prenylindole alkaloids in the late, whose species have previously been placed in Raputia. (author)

Enantioselective apoptosis induced by individual isomers of bifenthrin in Hep G2 cells.

Science.gov (United States)

Liu, Huigang; Li, Juan

2015-03-01

Bifenthrin (BF) has been used in racemate for agricultural purposes against soil insects, leading to increased inputs into soil environments. However, most of the studies about the toxicology research on BF were performed in its racemic form. The aim of the present study was to evaluate the enantiomer-specific cis-BF-induced apoptosis and intracellular reactive oxygen species (ROS) generation on human hepatocarcinoma cells (Hep G2). The results of cell viability assay and cytoflow assay indicated an obvious enantioselective hepatocyte toxicity of 1S-cis-BF in Hep G2 cells. 1S-cis-BF also induced ROS production, up-regulated Bax protein expression and down-regulated Bcl-2 expression levels. The present study suggested that enantioselective toxicity should be evaluated on currently used chiral pesticides, such as synthetic pyrethroids. Copyright © 2015 Elsevier B.V. All rights reserved.

Aptamer-Based Molecular Recognition of Lysergamine, Metergoline and Small Ergot Alkaloids

Directory of Open Access Journals (Sweden)

Johan Robbens

2012-12-01

Full Text Available Ergot alkaloids are mycotoxins produced by fungi of the genus Claviceps, which infect cereal crops and grasses. The uptake of ergot alkaloid contaminated cereal products can be lethal to humans and animals. For food safety assessment, analytical techniques are currently used to determine the presence of ergot alkaloids in food and feed samples. However, the number of samples which can be analyzed is limited, due to the cost of the equipment and the need for skilled personnel. In order to compensate for the lack of rapid tests for the detection of ergot alkaloids, the aim of this study was to develop a specific recognition element for ergot alkaloids, which could be further applied to produce a colorimetric reaction in the presence of these toxins. As recognition elements, single-stranded DNA ligands were selected by using an iterative selection procedure named SELEX, i.e., Systematic Evolution of Ligands by EXponential enrichment. After several selection cycles, the resulting aptamers were cloned and sequenced. A surface plasmon resonance analysis enabled determination of the dissociation constants of the complexes of aptamers and lysergamine. Dissociation constants in the nanomolar range were obtained with three selected aptamers. One of the selected aptamers, having a dissociation constant of 44 nM, was linked to gold nanoparticles and it was possible to produce a colorimetric reaction in the presence of lysergamine. This system could also be applied to small ergot alkaloids in an ergot contaminated flour sample.

Antiprotozoal alkaloids from Psychotria prunifolia (Kunth) Steyerm

International Nuclear Information System (INIS)

Kato, Lucilia; Oliveira, Cecilia M.A. de; Faria, Emiret O.; Ribeiro, Laryssa C.; Carvalho, Brenda G.; Silva, Cleuza C. da; Santin, Silvana M.O.; Schuque, Ivania T.A.; Nakamura, Celso V.; Britta, Elisandra A.; Miranda, Nathielle; Iglesias, Amadeu H.; Delprete, Piero G.

2012-01-01

The continuity of the phyto chemical study of crude extracts of P. prunifolia's roots and branches led to the isolation of five indole-β-carboline alkaloids. Among them, the 10-hydroxy-iso-deppeaninol and N-oxide-10-hydroxy-antirhine derivatives are described here for the first time. The structures were achieved through 1D and 2D NMR, IR and HRMS analyses. The branches and roots crude extracts and the alkaloids 14-oxoprunifoleine and strictosamide showed selective activity against L. amazonensis, with IC 50 values of 16.0 and 40.7 μg per mL, respectively. (author)

Cinchona alkaloids in asymmetric organocatalysis

NARCIS (Netherlands)

Marcelli, T.; Hiemstra, H.

2010-01-01

This article reviews the applications of cinchona alkaloids as asymmetric catalysts. In the last few years, characterized by the resurgence of interest in asymmetric organocatalysis, cinchona derivatives have been shown to catalyze an outstanding array of chemical reactions, often with remarkable

Pyrrolizidine alkaloids from Heliotropium megalanthum.

Science.gov (United States)

Reina, M; Gonzalez-Coloma, A; Gutierrez, C; Cabrera, R; Henriquez, J; Villarroel, L

1998-11-01

Two pyrrolizidine alkaloids, megalanthonine (1) and lycopsamine (2), have been isolated from Heliotropium megalanthum. The structure of the novel compound 1 was determined by spectroscopic methods. The insecticidal, antifeedant, and antifungal effects of compounds 1 and 2 have been evaluated.

Pyrrole alkaloids from the fruits of Morus alba.

Science.gov (United States)

Kim, Seon Beom; Chang, Bo Yoon; Hwang, Bang Yeon; Kim, Sung Yeon; Lee, Mi Kyeong

2014-12-15

Phytochemical investigation of the fruits of Morus alba afforded seventeen pyrrole alkaloids including five new compounds. The structures of five new pyrrole alkaloids, named morroles B-F (4, 5, 7, 16 and 17), were determined on the basis of spectroscopic interpretations. 4-[Formyl-5-(hydroxymethyl)-1H-pyrrol-1-yl]butanoate (2) was synthesized by chemical reaction but first isolated from nature. Among isolated compounds, compounds 6 and 14 significantly inhibited pancreatic lipase activity. Copyright © 2014 Elsevier Ltd. All rights reserved.

A catalytic reactor for the organocatalyzed enantioselective continuous flow alkylation of aldehydes.

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Porta, Riccardo; Benaglia, Maurizio; Puglisi, Alessandra; Mandoli, Alessandro; Gualandi, Andrea; Cozzi, Pier Giorgio

2014-12-01

The use of immobilized metal-free catalysts offers the unique possibility to develop sustainable processes in flow mode. The challenging intermolecular organocatalyzed enantioselective alkylation of aldehydes was performed for the first time under continuous flow conditions. By using a packed-bed reactor filled with readily available supported enantiopure imidazolidinone, different aldehydes were treated with three distinct cationic electrophiles. In the organocatalyzed α-alkylation of aldehydes with 1,3-benzodithiolylium tetrafluoroborate, excellent enantioselectivities, in some cases even better than those obtained in the flask process (up to 95% ee at 25 °C), and high productivity (more than 3800 h(-1) ) were obtained, which thus shows that a catalytic reactor may continuously produce enantiomerically enriched compounds. Treatment of the alkylated products with Raney-nickel furnished enantiomerically enriched α-methyl derivatives, key intermediates for active pharmaceutical ingredients and natural products. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Enantioselective effect of bifenthrin on antioxidant enzyme gene expression and stress protein response in PC12 cells.

Science.gov (United States)

Lu, Xianting

2013-07-01

Enantioselectivity in toxicology and the health risk of chiral xenobiotics have become frontier topics interfacing chemistry and toxicology. Our previous results showed that cis-bifenthrin (cis-BF) induced cytotoxicity and apoptosis in vitro in an enantioselective manner. However, the exact molecular mechanisms of synthetic pyrethroid-induced enantioselective apoptosis and cytotoxicity have so far received limited research attention. In the present study, the expression patterns of different genes encoding heat shock protein and antioxidant enzymes were investigated by real-time quantitative PCR in rat adrenal pheochromocytoma (PC12) cells after exposure to cis-BF and its enantiomers. The results showed that exposure to 1S-cis-BF resulted in increased transcription of HSP90, HSP70, HSP60, Cu-Zn-superoxide dismutase, Mn-superoxide dismutase, catalase and glutathione-s-transferase at a concentration of 5 µm and above, while exposure to 1R-cis-BF and rac-cis-BF exhibited these effects to lesser degrees. In addition, induction of antioxidant enzyme gene expression produced by 1S-cis-BF might occur, at least in part, through activation of p38 mitogen-activated protein kinases (MAPK) and extracellular regulated kinases, while increase in stress protein response produced by 1S-cis-BF might occur through the p38 MAPK signaling pathway. The results not only suggest that enantioselectivity should be considered in evaluating the ecotoxicological effects and health risk of chiral contaminants, but also will improve the understanding of molecular mechanism for chiral chemical-induced cytotoxicity. Copyright © 2012 John Wiley & Sons, Ltd.

Asymmetric Synthesis of Optically Active Spirocyclic Indoline Scaffolds through an Enantioselective Reduction of Indoles

KAUST Repository

Borrmann, Ruediger; Knop, Nils; Rueping, Magnus

2016-01-01

An enantioselective synthesis of spirocyclic indoline scaffolds was achieved by applying an asymmetric iridium-catalyzed hydrogenation of 3H-indoles. Low catalyst loadings and mild reaction conditions provide a broad range of differently substituted

A Concise Synthesis of the Erythrina Alkaloid 3–Demethoxyerythratidinone via Combined Rhodium Catalysis

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Joo, Jung Min; David, Ramoncito A.; Yuan, Yu; Lee, Chulbom

2010-01-01

The total synthesis of the erythrina alkaloid 3–demethoxyerythratidinone has been achieved via a strategy based on combined rhodium catalysis. The catalytic tandem cyclization effected by the interplay of alkynyl and vinylidene rhodium species allows for efficient access to the A and B rings of the tetracyclic erythrinane skeleton in a single step. The synthesis also features rapid preparation of the requisite precursor for the double ring closure and thus has been completed in only 7 total steps in 41% overall yield. PMID:21090648

Enantioselective Effects of o,p'-DDT on Cell Invasion and Adhesion of Breast Cancer Cells: Chirality in Cancer Development.

Science.gov (United States)

He, Xiangming; Dong, Xiaowu; Zou, Dehong; Yu, Yang; Fang, Qunying; Zhang, Quan; Zhao, Meirong

2015-08-18

The o,p'-dichlorodiphenyltrichloroethane (DDT) with a chiral center possesses enantioselective estrogenic activity, in which R-(-)-o,p'-DDT exerts a more potent estrogenic effect than S-(+)-o,p'-DDT. Although concern regarding DDT exposure and breast cancer has increased in recent decades, the mode of enantioselective action of o,p'-DDT in breast cancer development is still unknown. Herein, we conducted a systematic study of the effect of o,p'-DDT on stereoselective breast tumor cell progression in a widely used in vitro breast tumor cell model, MCF-7 cells. We demonstrated that R-(-)-o,p'-DDT promoted more cancer cell invasion mediated by the human estrogen receptor (ER) by inducing invasion-promoted genes (matrix metalloproteinase-2 and -9 and human telomerase reverse transcriptase) and inhibiting invasion-inhibited genes (tissue inhibitor of metalloproteinase-1 and -4). Molecular docking verified that the binding affinity between R-(-)-o,p'-DDT and human ER was stronger than that of S-(+)-o,p'-DDT. The enantioselective-induced decrease in cell-to-cell adhesion may involve the downregulation of adhesion-promoted genes (E-cadherin and β-catenin). For the first time, these results reveal that estrogenic-like chiral compounds are of significant concern in the progression of human cancers and that human health risk assessment of chiral chemicals should consider enantioselectivity.

Exploiting nanospace for asymmetric catalysis: confinement of immobilized, single-site chiral catalysts enhances enantioselectivity.

Science.gov (United States)

Thomas, John Meurig; Raja, Robert

2008-06-01

In the mid-1990s, it became possible to prepare high-area silicas having pore diameters controllably adjustable in the range ca. 20-200 Å. Moreover, the inner walls of these nanoporous solids could be functionalized to yield single-site, chiral, catalytically active organometallic centers, the precise structures of which could be determined using in situ X-ray absorption and FTIR and multinuclear magic angle spinning (MAS) NMR spectroscopy. This approach opened up the prospect of performing heterogeneous enantioselective conversions in a novel manner, under the spatial restrictions imposed by the nanocavities within which the reactions occur. In particular, it suggested an alternative method for preparing pharmaceutically and agrochemically useful asymmetric products by capitalizing on the notion, initially tentatively perceived, that spatial confinement of prochiral reactants (and transition states formed at the chiral active center) would provide an altogether new method of boosting the enantioselectivity of the anchored chiral catalyst. Initially, we anchored chiral single-site heterogeneous catalysts to nanopores covalently via a ligand attached to Pd(II) or Rh(I) centers. Later, we employed a more convenient and cheaper electrostatic method, relying in part on strong hydrogen bonding. This Account provides many examples of these processes, encompassing hydrogenations, oxidations, and aminations. Of particular note is the facile synthesis from methyl benzoylformate of methyl mandelate, which is a precursor in the synthesis of pemoline, a stimulant of the central nervous system; our procedure offers several viable methods for reducing ketocarboxylic acids. In addition to relying on earlier (synchrotron-based) in situ techniques for characterizing catalysts, we have constructed experimental procedures involving robotically controlled catalytic reactors that allow the kinetics of conversion and enantioselectivity to be monitored continually, and we have access to

Exploration of Cocatalyst Effects on a Bimetallic Cobalt Catalyst System: Enhanced Activity and Enantioselectivity in Epoxide Polymerization

KAUST Repository

Widger, Peter C. B.; Ahmed, Syud M.; Coates, Geoffrey W.

2011-01-01

Organic ionic compounds were synthesized and investigated as cocatalysts with a bimetallic cobalt complex for enantioselective epoxide polymerization. The identities of both the cation and the anion were systematically varied, and the subsequent reactivity was studied. The nature of the ionic cocatalyst dramatically impacted the rate and enantioselectivity of the catalyst system. The ionic cocatalyst [P(N=P(N(CH2)4)3) 4 +][tBuCO2 -] in combination with a bimetallic cobalt complex produced a catalyst system that exhibited the greatest activity and selectivity for a variety of monosubstituted epoxides. © 2011 American Chemical Society.

Exploration of Cocatalyst Effects on a Bimetallic Cobalt Catalyst System: Enhanced Activity and Enantioselectivity in Epoxide Polymerization

KAUST Repository

Widger, Peter C. B.

2011-07-26

Organic ionic compounds were synthesized and investigated as cocatalysts with a bimetallic cobalt complex for enantioselective epoxide polymerization. The identities of both the cation and the anion were systematically varied, and the subsequent reactivity was studied. The nature of the ionic cocatalyst dramatically impacted the rate and enantioselectivity of the catalyst system. The ionic cocatalyst [P(N=P(N(CH2)4)3) 4 +][tBuCO2 -] in combination with a bimetallic cobalt complex produced a catalyst system that exhibited the greatest activity and selectivity for a variety of monosubstituted epoxides. © 2011 American Chemical Society.

Biological activity of the alkaloids of Erythroxylum coca and Erythroxylum novogranatense

NARCIS (Netherlands)

Salemink, C.A.; Novák, M.; Khan, I.

1984-01-01

The cultivated Erythroxylum varieties E. coca var. coca, E. coca var. ipadu, E. novogranatense var. novogranatense and E. novogranatense var. truxillense contain 18 alkaloids, identified so far, belonging to the tropanes, pyrrolidines and pyridines, with cocaine as the main alkaloid. The biological

Ruthenium Catalyzed Diastereo- and Enantioselective Coupling of Propargyl Ethers with Alcohols: Siloxy-Crotylation via Hydride Shift Enabled Conversion of Alkynes to π-Allyls.

Science.gov (United States)

Liang, Tao; Zhang, Wandi; Chen, Te-Yu; Nguyen, Khoa D; Krische, Michael J

2015-10-14

The first enantioselective carbonyl crotylations through direct use of alkynes as chiral allylmetal equivalents are described. Chiral ruthenium(II) complexes modified by Josiphos (SL-J009-1) catalyze the C-C coupling of TIPS-protected propargyl ether 1a with primary alcohols 2a-2o to form products of carbonyl siloxy-crotylation 3a-3o, which upon silyl deprotection-reduction deliver 1,4-diols 5a-5o with excellent control of regio-, anti-diastereo-, and enantioselectivity. Structurally related propargyl ethers 1b and 1c bearing ethyl- and phenyl-substituents engage in diastereo- and enantioselective coupling, as illustrated in the formation of adducts 5p and 5q, respectively. Selective mono-tosylation of diols 5a, 5c, 5e, 5f, 5k, and 5m is accompanied by spontaneous cyclization to deliver the trans-2,3-disubstituted furans 6a, 6c, 6e, 6f, 6k, and 6m, respectively. Primary alcohols 2a, 2l, and 2p were converted to the siloxy-crotylation products 3a, 3l, and 3p, which upon silyl deprotection-lactol oxidation were transformed to the trans-4,5-disubstituted γ-butyrolactones 7a, 7l, and 7p. The formation of 7p represents a total synthesis of (+)-trans-whisky lactone. Unlike closely related ruthenium catalyzed alkyne-alcohol C-C couplings, deuterium labeling studies provide clear evidence of a novel 1,2-hydride shift mechanism that converts metal-bound alkynes to π-allyls in the absence of intervening allenes.

Protein and alkaloid patterns of the floral nectar in some solanaceous species.

Science.gov (United States)

Kerchner, András; Darók, Judit; Bacskay, Ivett; Felinger, Attila; Jakab, Gábor; Farkas, Ágnes

2015-09-01

The family Solanaceae includes several melliferous plants, which tend to produce copious amounts of nectar. Floral nectar is a chemically complex aqueous solution, dominated by sugars, but minor components such as amino acids, proteins, flavonoids and alkaloids are present as well. This study aimed at analysing the protein and alkaloid profile of the nectar in seven solanaceous species. Proteins were examined with SDS-PAGE and alkaloids were analyzed with HPLC. The investigation of protein profile revealed significant differences in nectar-protein patterns not only between different plant genera, but also between the three Nicotiana species investigated. SDS-PAGE suggested the presence of several Nectarin proteins with antimicrobial activity in Nicotiana species. The nectar of all tobacco species contained the alkaloid nicotine, N. tabacum having the highest nicotine content. The nectar of Brugmansia suaveolens, Datura stramonium, Hyoscyamus niger and Lycium barbarum contained scopolamine, the highest content of which was measured in B. suaveolens. The alkaloid concentrations in the nectars of most solanaceous species investigated can cause deterrence in honeybees, and the nectar of N. rustica and N. tabacum can be considered toxic for honeybees.

Design, Synthesis and Biological Activity of Novel Reversible Peptidyl FVIIa Inhibitors Rh-Catalyzed Enantioselective Synthesis of Diaryl Amines

DEFF Research Database (Denmark)

Storgaard, Morten

functional group tolerance. Unfortunately, these -aryl tetramic acids were too unreactive and ring opening toward the synthesis of the building block did not succeed. However, -aryl tetramic acids are still interesting compounds due to their potential biological activity. The building block 3.15 (P1......-catalyzed enantioselective synthesis of diaryl amines, which is an important class of compounds (Chapter 4). For example it is found in the third generation anti-histaminic agent levocetirizine. Development of efficient synthetic routes is therefore of considerably interest. The rhodium-catalyzed enantioselective synthesis...

Stereospecific nickel-catalyzed cross-coupling reactions of alkyl ethers: enantioselective synthesis of diarylethanes.

Science.gov (United States)

Taylor, Buck L H; Swift, Elizabeth C; Waetzig, Joshua D; Jarvo, Elizabeth R

2011-01-26

Secondary benzylic ethers undergo stereospecific substitution reactions with Grignard reagents in the presence of nickel catalysts. Reactions proceed with inversion of configuration and high stereochemical fidelity. This reaction allows for facile enantioselective synthesis of biologically active diarylethanes from readily available optically enriched carbinols.

Changes in plant defense chemistry (pyrrolizidine alkaloids) revealed through high-resolution spectroscopy

Science.gov (United States)

Carvalho, Sabrina; Macel, Mirka; Schlerf, Martin; Moghaddam, Fatemeh Eghbali; Mulder, Patrick P. J.; Skidmore, Andrew K.; van der Putten, Wim H.

2013-06-01

Plant toxic biochemicals play an important role in defense against natural enemies and often are toxic to humans and livestock. Hyperspectral reflectance is an established method for primary chemical detection and could be further used to determine plant toxicity in the field. In order to make a first step for pyrrolizidine alkaloids detection (toxic defense compound against mammals and many insects) we studied how such spectral data can estimate plant defense chemistry under controlled conditions. In a greenhouse, we grew three related plant species that defend against generalist herbivores through pyrrolizidine alkaloids: Jacobaea vulgaris, Jacobaea erucifolia and Senecio inaequidens, and analyzed the relation between spectral measurements and chemical concentrations using multivariate statistics. Nutrient addition enhanced tertiary-amine pyrrolizidine alkaloids contents of J. vulgaris and J. erucifolia and decreased N-oxide contents in S. inaequidens and J. vulgaris. Pyrrolizidine alkaloids could be predicted with a moderate accuracy. Pyrrolizidine alkaloid forms tertiary-amines and epoxides were predicted with 63% and 56% of the variation explained, respectively. The most relevant spectral regions selected for prediction were associated with electron transitions and Csbnd H, Osbnd H, and Nsbnd H bonds in the 1530 and 2100 nm regions. Given the relatively low concentration in pyrrolizidine alkaloids concentration (in the order of mg g-1) and resultant predictions, it is promising that pyrrolizidine alkaloids interact with incident light. Further studies should be considered to determine if such a non-destructive method may predict changes in PA concentration in relation to plant natural enemies. Spectroscopy may be used to study plant defenses in intact plant tissues, and may provide managers of toxic plants, food industry and multitrophic-interaction researchers with faster and larger monitoring possibilities.

Interactions between β-carboline alkaloids and bovine serum albumin: Investigation by spectroscopic approach

International Nuclear Information System (INIS)

Nafisi, Shohreh; Panahyab, Ataollah; Bagheri Sadeghi, Golshan

2012-01-01

β-Carboline alkaloids are present in medicinal plants such as Peganum harmala L. that have been used as folk medicine in anticancer therapy. BSA is the major soluble protein constituent of the circulatory system, and has many physiological functions including the transport of a variety of compounds. This study is the first attempt to investigate the binding of β-carboline alkaloids to BSA by using a constant protein concentration and varying drug concentrations at pH 7.2. FTIR and UV–Vis spectroscopic methods were used to analyze the binding modes of β-carboline alkaloids, the binding constants and the effects of drug complexation on BSA stability and conformation. Spectroscopic evidence showed that β-carboline alkaloids bind BSA via hydrophobic interaction and van der Waals contacts along with H-bonding with the –NH groups, with overall binding constants of K harmine–BSA =2.04×10 4 M −1 , K tryptoline–BSA =1.2×10 4 M −1 , K harmaline–BSA =5.04×10 3 M −1 , K harmane–BSA =1.41×10 3 M −1 and K harmalol–BSA =1.01×10 3 M −1 , assuming that there is one drug molecule per protein. The BSA secondary structure was altered with a major decrease of α-helix from 64% (free protein) to 59% (BSA–harmane), 56% (BSA–harmaline and BSA–harmine), 55% (BSA–tryptoline), 54% (BSA–harmalol) and β-sheet from 15% (free protein) to 6–8% upon β-carboline alkaloids complexation, inducing a partial protein destabilization. - Highlights: ► We model the binding of β-carboline alkaloids to BSA by using the spectroscopic methods. ► We investigate the effects of drug complexation on BSA stability and conformation. ► A partial protein destabilization occurred at high alkaloids concentration. ► Alkaloids bind BSA via hydrophobic interactions and H-bonding with the ---NH groups. ► BSA can be considered as a good carrier for transportation of β-carboline alkaloids.

Hexacyclic monoterpenoid indole alkaloids from Rauvolfia verticillata.

Science.gov (United States)

Gao, Yuan; Yu, Ai-Lin; Li, Gen-Tao; Hai, Ping; Li, Yan; Liu, Ji-Kai; Wang, Fei

2015-12-01

Five new hexacyclic monoterpenoid indole alkaloids, rauvovertine A (1), 17-epi-rauvovertine A (2), rauvovertine B (3), 17-epi-rauvovertine B (4), and rauvovertine C (5) together with 17 known analogues were isolated from the stems of Rauvolfia verticillata. Compounds 1/2 and 3/4 were obtained as C-17 epimeric mixtures due to rapid hemiacetal tautomerism in solution. The structures of 1-5 were established by spectroscopic analysis and with the aid of molecular modeling. The new alkaloids were evaluated for their cytotoxicity in vitro against human tumor HL-60, SMMC-7721, A-549, MCF-7, and SW-480 cell lines. Copyright © 2015 Elsevier B.V. All rights reserved.

Analysis of Alkaloids from Physalis peruviana by Capillary GC, Capillary GC-MS, and GC-FTIR.

Science.gov (United States)

Kubwabo, C; Rollmann, B; Tilquin, B

1993-04-01

The alkaloid composition of the aerial parts and roots of PHYSALIS PERUVIANA was analysed by capillary GC (GC (2)), GC (2)-MS and GC (2)-FTIR. Eight alkaloids were identified, three of those alkaloids are 3beta-acetoxytropane and two N-methylpyrrolidinylhygrine isomers, which were not previously found in the genus PHYSALIS. A reproduction of the identification of alkaloids detected in the plant by the use of retention indices has been proposed.

How polyamine synthesis inhibitors and cinnamic acid affect tropane alkaloid production.

Science.gov (United States)

Marconi, Patricia L; Alvarez, María A; Pitta-Alvarez, Sandra I

2007-01-01

Hairy roots of Brugmansia candida produce the tropane alkaloids scopolamine and hyoscyamine. In an attempt to divert the carbon flux from competing pathways and thus enhance productivity, the polyamine biosynthesis inhibitors cyclohexylamine (CHA) and methylglyoxal-bis-guanylhydrazone (MGBG) and the phenylalanine-ammonia-lyase inhibitor cinnamic acid were used. CHA decreased the specific productivity of both alkaloids but increased significantly the release of scopolamine (approx 500%) when it was added in the mid-exponential phase. However, when CHA was added for only 48 h during the exponential phase, the specific productivity of both alkaloids increased (approx 200%), favoring scopolamine. Treatment with MGBG was detrimental to growth but promoted release into the medium of both alkaloids. However, when it was added for 48 h during the exponential phase, MGBG increased the specific productivity (approx 200%) and release (250- 1800%) of both alkaloids. Cinnamic acid alone also favored release but not specific productivity. When a combination of CHA or MGBG with cinnamic acid was used, the results obtained were approximately the same as with each polyamine biosynthesis inhibitor alone, although to a lesser extent. Regarding root morphology, CHA inhibited growth of primary roots and ramification. However, it had a positive effect on elongation of lateral roots.

Isolation, biosynthesis and biological activity of alkaloids of Tylophora asthmatica, a versatile medicinal plant

International Nuclear Information System (INIS)

Mulchandani, N.B.

1987-01-01

Tylophorine and related new alkaloids have been isolated from Tylophora asthmatics, Pergularia pallida and Ficus hispida plants. Biosynthesis of this group of alkaloids has been carried out using various labelled precursors for the first time and from the systematic degradation of the isolated radiolabelled tylophorine, it has been concluded that these alkaloids arise from one molecule each of tyrosine, phenylalanine and ornithine. The interactions of Tylophora alkaloids particularly tylophorinidine with biomolecules such as lysozyme and bovine serum albumin have also been studied and binding characteristics determined. It was found that Tylophora alkaloid extract possesses antianaphylactic activity as observed in passive peritoneal anaphylaxis in rats. The drug also possessed mild antihistaminic and anticholinergic activities. Studies of the extract on the bronchial smooth muscle both in vivo and in vitro did not reveal bronchiodilator potential of the drug. In addition, the distribution and metabolism of the drug was studied in vivo using 14 C radiolabelled alkaloids prepared by biosynthetic method. This study further revealed its usefulness since the drug is absorbed by vital organs and also it is not metabolised into fragments which could cause some other damage. Tylophora alkaloids have also been found to be anti-mutagenic. 10 tables, 5 figures, 24 refs. (author)

Antiparasitic activities of acridone alkaloids from Swinglea glutinosa (Bl.) Merr

Energy Technology Data Exchange (ETDEWEB)

Santos, Djalma A.P. dos; Vieira, Paulo C; Silva, M. Fatima das G.F. da; Fernandes, Joao B [Universidade Federal de Sao Carlos, SP (Brazil). Dept. de Quimica; Rattray, Lauren; Croft, Simon L [London School of Hygiene and Tropical Medicine, London (United Kingdom). Dept. of Infectious and Tropical Diseases

2009-07-01

Eleven acridone alkaloids isolated from Swinglea glutinosa (Bl.) Merr. were examined for in vitro activity against chloroquine-sensitive Plasmodium falciparum 3D7, Trypanosoma brucei rhodesiense STIB900 and Leishmania donovani L82. An assay with KB cells was developed in order to compare in vitro toxicity of alkaloids with the selective action on the parasites. Nine of the compounds had IC{sub 50} values ranging from 0.3 to 11.6 {mu}M against P. falciparum. In contrast, a small number of compounds showed significant activity against T. brucei rhodesiense and none had activity against L. donovani. Among the alkaloids three had IC{sub 50} < 1.0 {mu}M against P. falciparum, whereas against T. b. rhodesiense five had IC{sub 50} < 10 {mu}M. The characterization of the acridone alkaloids, 1,3,5-trihydroxy-4-methoxy-10-methyl-2,8-bis(3-methylbut-2-enyl)acridin-9 (10H)-one (1), 2,3-dihydro-4,9-dihydroxy-2-(2-hydroxypropan-2-yl)-11-methoxy-10-methylfuro [3,2-b] acridin-5(10H)-one (2) and 3,4-dihydro-3,5,8-trihydroxy-6-methoxy-2,2,7-trimethyl-2Hpyrano[ 2,3-a]acridin-12(7H)-one (3), is discussed, as well as the structure-activity relationship of all compounds assayed. Isolation and spectral data of alkaloids 1-3 are described for the first time although their cytotoxicities to cancer cells have been described before. (author)

Ornithine decarboxylase, polyamines, and pyrrolizidine alkaloids in senecio and crotalaria.

Science.gov (United States)

Birecka, H; Birecki, M; Cohen, E J; Bitonti, A J; McCann, P P

1988-01-01

When tested for ornithine and arginine decarboxylases, pyrrolizidine alkaloid-bearing Senecio riddellii, S. longilobus (Compositae), and Crotalaria retusa (Leguminosae) plants exhibited only ornithine decarboxylase activity. This contrasts with previous studies of four species of pyrrolizidine alkaloid-bearing Heliotropium (Boraginaceae) in which arginine decarboxylase activity was very high relative to that of ornithine decarboxylase. Unlike Heliotropium angiospermum and Heliotropium indicum, in which endogenous arginine was the only detectable precursor of putrescine channeled into pyrrolizidines, in the species studied here-using difluoromethylornithine and difluoromethylarginine as the enzyme inhibitors-endogenous ornithine was the main if not the only precursor of putrescine converted into the alkaloid aminoalcohol moiety. In S. riddellii and C. retusa at flowering, ornithine decarboxylase activity was present mainly in leaves, especially the young ones. However, other very young organs such as inflorescence and growing roots exhibited much lower or very low activities; the enzyme activity in stems was negligible. There was no correlation between the enzyme activity and polyamine or alkaloid content in either species. In both species only free polyamines were detected except for C. retusa roots and inflorescence-with relatively very high levels of these compounds-in which conjugated putrescine, spermidine, and spermine were also found; agmatine was not identified by HPLC in any plant organ except for C. retusa roots with rhizobial nodules. Organ- or age-dependent differences in the polyamine levels were small or insignificant. The highest alkaloid contents were found in young leaves and inflorescence.

Biosistematik species Annona muricata Annona squamosa dan Annona reticulata dengan pendekatan alkaloid

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Hamidah Hamidah

2013-03-01

Full Text Available This research aimed to explore kinship Annona muricata, Annona squamosa and Annona reticulata on the basis alkaloid content. Study phenotype Annona muricata, Annona squamosa and Annona reticulata based alkaloid content. Data alkaloid obtained are thenprocessed by a computer program SPSS version 14. The results of this study indicate that the presence of variations in the characterof the three types of Annona of species alkaloid. From the data analysis it can be seen that there are differences in the variations that occur in Annona muricata, Annona squamosa and Annona reticulata by different habitats and is a variation of phenotypic variation.Dendrogram grouping results suggest that Annona squamosa and Annona reticulata fenetic ties closer, so clumped into one large group while Annona muricata split away from the other groups.

Efficient total synthesis of (S)-14-azacamptothecin.

Science.gov (United States)

Liu, Guan-Sai; Yao, Yuan-Shan; Xu, Peng; Wang, Shaozhong; Yao, Zhu-Jun

2010-06-01

An efficient total synthesis of (S)-14-azacamptothecin has been accomplished in 10 steps and 56% overall yield from 5H-pyrano[4,3-d]pyrimidine 8. A mild Hendrickson reagent-triggered intramolecular cascade cyclization, a highly enantioselective dihydroxylation, and an efficient palladium-catalyzed transformation of an O-allyl into N-allyl group are the key steps in the synthesis. This work provides a much higher overall yield than the previous achievement and shows sound flexibility for the further applications that will lead to new bioactive analogues.

Chemo- and Enantioselective Intramolecular Silver-Catalyzed Aziridinations.

Science.gov (United States)

Ju, Minsoo; Weatherly, Cale D; Guzei, Ilia A; Schomaker, Jennifer M

2017-08-07

Asymmetric nitrene-transfer reactions are a powerful tool for the preparation of enantioenriched amine building blocks. Reported herein are chemo- and enantioselective silver-catalyzed aminations which transform di- and trisubstituted homoallylic carbamates into [4.1.0]-carbamate-tethered aziridines in good yields and with ee values of up to 92 %. The effects of the substrate, silver counteranion, ligand, solvent, and temperature on both the chemoselectivity and ee value were explored. Stereochemical models were proposed to rationalize the observed absolute stereochemistry of the aziridines, which undergo nucleophilic ring opening to yield enantioenriched amines with no erosion in stereochemical integrity. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Enantioselective copper-catalyzed carboetherification of unactivated alkenes.

Science.gov (United States)

Bovino, Michael T; Liwosz, Timothy W; Kendel, Nicole E; Miller, Yan; Tyminska, Nina; Zurek, Eva; Chemler, Sherry R

2014-06-16

Chiral saturated oxygen heterocycles are important components of bioactive compounds. Cyclization of alcohols onto pendant alkenes is a direct route to their synthesis, but few catalytic enantioselective methods enabling cyclization onto unactivated alkenes exist. Herein reported is a highly efficient copper-catalyzed cyclization of γ-unsaturated pentenols which terminates in C-C bond formation, a net alkene carboetherification. Both intra- and intermolecular C-C bond formations are demonstrated, thus yielding functionalized chiral tetrahydrofurans as well as fused-ring and bridged-ring oxabicyclic products. Transition-state calculations support a cis-oxycupration stereochemistry-determining step. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chiral separation and enantioselective degradation of vinclozolin in soils.

Science.gov (United States)

Liu, Hui; Liu, Donghui; Shen, Zhigang; Sun, Mingjing; Zhou, Zhiqiang; Wang, Peng

2014-03-01

Vinclozolin is a chiral fungicide with potential environmental problems. The chiral separation of the enantiomers and enantioselective degradation in soil were investigated in this work. The enantiomers were separated by high-performance liquid chromatography (HPLC) on Chiralpak IA, IB, and AZ-H chiral columns under normal phase and the influence of the mobile phase composition on the separation was also studied. Complete resolutions were obtained on all three chiral columns under optimized conditions with the same elution order of (+)/(-). The residual analysis of the enantiomers in soil was conducted using accelerate solvent extraction followed by HPLC determination. The recoveries of the enantiomers ranged from 85.7-105.7% with relative standard deviation (SD) of 0.12-3.83%, and the limit of detection (LOD) of the method was 0.013 µg/g. The results showed that the degradations of vinclozolin enantiomers in the soils followed first-order kinetics. Preferential degradation of the (-)-enantiomer was observed only in one soil with the largest |ES| value of 0.047, and no obvious enantioselective degradation was observed in other soils. It was found that the persistence of vinclozolin in soil was related to pH values based on the half-lives. The two enantiomers disappeared about 8 times faster in basic soils than that in neutral or acidic soils. © 2014 Wiley Periodicals, Inc.

Indole alkaloids and other constituents of Rauwolfia serpentina.

Science.gov (United States)

Itoh, Atsuko; Kumashiro, Tomoko; Yamaguchi, Machiko; Nagakura, Naotaka; Mizushina, Yoshiyuki; Nishi, Toyoyuki; Tanahashi, Takao

2005-06-01

From the dried roots of Rauwolfia serpentina were isolated five new indole alkaloids, N(b)-methylajmaline (1), N(b)-methylisoajmaline (2), 3-hydroxysarpagine (3), yohimbinic acid (4), isorauhimbinic acid (5), a new iridoid glucoside, 7-epiloganin (6), and a new sucrose derivative, 6'-O-(3,4,5-trimethoxybenzoyl)glomeratose A (7), together with 20 known compounds. The structures of the new compounds were determined by spectroscopic and chemical means. The inhibitory activities of the selected alkaloids on topoisomerase I and II and their cytotoxicity against the human promyelocytic leukemia (HL-60) cell lines were assessed.

Tyrosine aminotransferase contributes to benzylisoquinoline alkaloid biosynthesis in opium poppy.

Science.gov (United States)

Lee, Eun-Jeong; Facchini, Peter J

2011-11-01

Tyrosine aminotransferase (TyrAT) catalyzes the transamination of L-Tyr and α-ketoglutarate, yielding 4-hydroxyphenylpyruvic acid and L-glutamate. The decarboxylation product of 4-hydroxyphenylpyruvic acid, 4-hydroxyphenylacetaldehyde, is a precursor to a large and diverse group of natural products known collectively as benzylisoquinoline alkaloids (BIAs). We have isolated and characterized a TyrAT cDNA from opium poppy (Papaver somniferum), which remains the only commercial source for several pharmaceutical BIAs, including codeine, morphine, and noscapine. TyrAT belongs to group I pyridoxal 5'-phosphate (PLP)-dependent enzymes wherein Schiff base formation occurs between PLP and a specific Lys residue. The amino acid sequence of TyrAT showed considerable homology to other putative plant TyrATs, although few of these have been functionally characterized. Purified, recombinant TyrAT displayed a molecular mass of approximately 46 kD and a substrate preference for L-Tyr and α-ketoglutarate, with apparent K(m) values of 1.82 and 0.35 mm, respectively. No specific requirement for PLP was detected in vitro. Liquid chromatography-tandem mass spectrometry confirmed the conversion of L-Tyr to 4-hydroxyphenylpyruvate. TyrAT gene transcripts were most abundant in roots and stems of mature opium poppy plants. Virus-induced gene silencing was used to evaluate the contribution of TyrAT to BIA metabolism in opium poppy. TyrAT transcript levels were reduced by at least 80% in silenced plants compared with controls and showed a moderate reduction in total alkaloid content. The modest correlation between transcript levels and BIA accumulation in opium poppy supports a role for TyrAT in the generation of alkaloid precursors, but it also suggests the occurrence of other sources for 4-hydroxyphenylacetaldehyde.

Effects of antibacterial agents on in vitro ovine ruminal biotransformation of the hepatotoxic pyrrolizidine alkaloid jacobine.

OpenAIRE

Wachenheim, D E; Blythe, L L; Craig, A M

1992-01-01

Ingestion of pyrrolizidine alkaloids, naturally occurring plant toxins, causes illness and death in a number of animal species. Senecio jacobaea pyrrolizidine alkaloids cause significant economic losses due to livestock poisoning, particularly in the Pacific Northwest. Some sheep are resistant to pyrrolizidine alkaloid poisoning, because ovine ruminal biotransformation detoxifies free pyrrolizidine alkaloids in digesta. Antibacterial agents modify ruminal fermentation. Pretreatment with antib...

OVIPOSITION AND OVICIDAL ACTIVITIES OF ALKALOIDAL ...

African Journals Online (AJOL)

1000 ppm concentration and ovicidal activity at 25-100 ppm concentration against Culex quinquefasciatus and Culex tritaeniorhynchus. Water treated with alkaloidal extract at 1000ppm received significantly more egg rafts of vector mosquitoes ...

Combining silver- and organocatalysis: an enantioselective sequential catalytic approach towards pyrano-annulated pyrazoles.

Science.gov (United States)

Hack, Daniel; Chauhan, Pankaj; Deckers, Kristina; Mizutani, Yusuke; Raabe, Gerhard; Enders, Dieter

2015-02-11

A one-pot asymmetric Michael addition/hydroalkoxylation sequence, catalyzed by a sequential catalytic system consisting of a squaramide and a silver salt, provides a new series of chiral pyrano-annulated pyrazole derivatives in excellent yields (up to 95%) and high enantioselectivities (up to 97% ee).

Crystal structure of indoline alkaloids kopsinilam, kopsinine, and the salts of the latter

DEFF Research Database (Denmark)

Adizov, Sh. M.; Tashkhodzhaev, B.; Kunafiev, R. Zh.

2016-01-01

N1 in the bases and the salts. Tetrahedral hybridization of the atom N1 in indoline alkaloids favors the formation of their double salts, what is unlikely for indole and indolinine alkaloids. In the halogen double salts there is an intramolecular Н bond between one of the protons of the NH2 group......Indoline alkaloids kopsinilam and kopsinine extracted from the plant Vinca erecta have been studied by X-ray crystallography; mono and double salts of the latter alkaloid also have been examined. Experimentally determined positions of Н atoms suggest sp3 hybridization of the indoline nitrogen atom...... and the oxygen of the methoxycarbonyl group, that is absent in the mono salts and pure bases....

Alternative extraction of alkaloid anticarcinogens from Brazilian "vinca rosea" using Ion exchange chromatography

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Sérgio Freire de Carvalhaes

Full Text Available Extracts in ethanol and ethanol-ammonia of dried leaves from Catharanthus roseus, gathered at Rio de Janeiro state, were adsorbed in a strongly acidic cation exchange resin with sulfonic acid group, using the finite bath method, resulting in an alkaloid retained fraction and an acidic and neutral unretained fraction. High Performance Liquid Chromatography showed the isolation of the alkaloid fraction to be highly selective and with good performance, with an absence of alkaloids in the unretained fraction, while the retained fraction presented 1,54-6,35 mg/g of vindoline and 0,12-0,91 mg/g of vinblastine, common for an alkaloid-rich concentrate, usually obtained by classic extraction with several steps using solvents.

A new enantioselective CE method for determination of oxcarbazepine and licarbazepine after fungal biotransformation.

Science.gov (United States)

Bocato, Mariana Zuccherato; Bortoleto, Marcela Armelim; Pupo, Mônica Tallarico; de Oliveira, Anderson Rodrigo Moraes

2014-10-01

The present work describes, for the first time, the simultaneous separation of oxcarbazepine (OXC) and its active metabolite 10-hydroxy-10,11-dihydrocarbamazepine (licarbazepine, Lic) by chiral CE. The developed method was employed to monitor the enantioselective biotransformation of OXC into its active metabolite by fungi. The electrophoretic separations were performed using 10 mmol/L of a Tris-phosphate buffer solution (pH 2.5) containing 1% w/v of β-CD phosphate sodium salt (P-β-CD) as running electrolyte, -20 kV of applied voltage and a 15°C capillary temperature. The method was linear over the concentration range of 1000-30 000 ng/mL for OXC and 75-900 ng/mL for each Lic enantiomer (r ≥ 0.9952). Within-day precision and accuracy evaluated by RSD and relative errors, respectively, were lower than 15% for all analytes. The validated method was used to evaluate the enantioselective biotransformation of OXC, mediated by fungi, into its active metabolite Lic. This study showed that the fungi Glomerella cingulata (VA1) and Beuveria bassiana were able to enantioselectively metabolize the OXC into Lic after 360 h of incubation. Biotransformation by the fungus Beuveria bassiana showed 79% enantiomeric excess for (S)-(+)-Lic, while VA1 gave an enantiomeric excess of 100% for (S)-(+)-Lic. This study opens a new route to the drug (S)-(+)-licarbazepine. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Alkaloid-Containing Plants Poisonous to Cattle and Horses in Europe.

Science.gov (United States)

Cortinovis, Cristina; Caloni, Francesca

2015-12-08

Alkaloids, nitrogen-containing secondary plant metabolites, are of major interest to veterinary toxicology because of their occurrence in plant species commonly involved in animal poisoning. Based on epidemiological data, the poisoning of cattle and horses by alkaloid-containing plants is a relatively common occurrence in Europe. Poisoning may occur when the plants contaminate hay or silage or when forage alternatives are unavailable. Cattle and horses are particularly at risk of poisoning by Colchicum autumnale (meadow saffron), Conium maculatum (poison hemlock), Datura stramonium (jimson weed), Equisetum palustre (marsh horsetail), Senecio spp. (ragwort and groundsel) and Taxus baccata (European yew). This review of poisonous alkaloid-containing plants describes the distribution of these plants, conditions under which poisoning occurs, active toxic principles involved and subsequent clinical signs observed.

A new alkaloid from the fruit of Nandina domestica Thunb.

Science.gov (United States)

Peng, Cai-Ying; Liu, Jian-Qun; Zhang, Rui; Shu, Ji-Cheng

2014-01-01

A new steroidal alkaloid, (20S,22R,24R)-24-ethyl-3-oxocholest-4-en-22-amino, named as nandsterine (1), together with 10 known alkaloids, palmatine (2), O-methylbulbocapnine (3), nantenine (4), dehydronantenine (5), glaucine (6), didehydroglaucine (7), dehydrocorydaline (8), jatrorrhizine (9), magnoflorine (10) and berberine (11), was isolated from the fruit of Nandina domestica Thunb. Their structures were elucidated by using spectroscopic methods as well as by comparing with the published data. Compound 1 was a new class of steroidal alkaloid isolated from the family Berberidaceae, meanwhile compounds 2, 3, 6-8 and 10 were obtained from N. domestica for the first time. Compound 1 exhibited cytotoxicity against HL-60 cells (human leukaemia) with IC50 values of 52.1 μM.

Uncovering Key Structural Features of an Enantioselective Peptide-Catalyzed Acylation Utilizing Advanced NMR Techniques

Czech Academy of Sciences Publication Activity Database

Procházková, Eliška; Kolmer, A.; Ilgen, J.; Schwab, M.; Kaltschnee, L.; Fredersdorf, M.; Schmidts, V.; Wende, R. C.; Schreiner, P. R.; Thiele, C. M.

2016-01-01

Roč. 55, č. 51 (2016), s. 15754-15759 ISSN 1433-7851 Institutional support: RVO:61388963 Keywords : conformational analysis * enantioselective acylations * NMR spectroscopy * pure shift NMR * RDCs Subject RIV: CC - Organic Chemistry Impact factor: 11.994, year: 2016

Molekulare Identifizierung und Charakterisierung der Flavin-abhängigen Monooxygenasen in verschiedenen Pyrrolizidin-Alkaloid-adaptierten Insekten

OpenAIRE

Wang, Linzhu

2013-01-01

Several insect lineages have developed diverse strategies to sequester toxic pyrrolizidine alkaloids from food-plants for their own defense. Here, we show that in two highly divergent insect taxa, the hemimetabolous grasshoppers and the holometabolous butterflies, an almost identical strategy evolved independently for safe accumulation of pyrrolizidine alkaloids. This strategy involves a pyrrolizidine alkaloid N-oxygenase that transfers the pyrrolizidine alkaloids to their respect...

Lycopodium alkaloids from Palhinhaea cernua

Energy Technology Data Exchange (ETDEWEB)

Zhao, Fu-Wei [Graduate University of Chinese Academy of Sciences, Beijing (China); Luo, Ji-Feng; Wang, Yue-Hu, E-mail: wangyuehu@mail.kib.ac.cn [Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences (China); Sun, Qian-Yun; Yang, Fu-Mei [Key Laboratory of Chemistry for Natural Products, Guizhou Province and Chinese Academy of Sciences (China); Liu, Fang [College of Landscape and Horticulture, Yunnan Agricultural University (China); Long, Chun-Lin, E-mail: long@mail.kib.ac.cn [College of Life and Environmental Sciences, Minzu University of China, Beijing, (China)

2012-07-01

Two new Lycopodium alkaloids, acetyllycoposerramine M and palcernine A were isolated from whole plant extracts of Palhinhaea cernua L. together with ten previously identified compounds. The structures of the new compounds were elucidated by spectroscopic methods and single-crystal X-ray diffraction analyses using the Flack parameter. (author)

Indole Alkaloids Inhibiting Neural Stem Cell from Uncaria rhynchophylla

OpenAIRE

Wei, Xin; Jiang, Li-Ping; Guo, Ying; Khan, Afsar; Liu, Ya-Ping; Yu, Hao-Fei; Wang, Bei; Ding, Cai-Feng; Zhu, Pei-Feng; Chen, Ying-Ying; Zhao, Yun-Li; Chen, Yong-Bing; Wang, Yi-Fen; Luo, Xiao-Dong

2017-01-01

Uncaria rhynchophylla is commonly recognized as a traditional treatment for dizziness, cerebrovascular diseases, and nervous disorders in China. Previously, the neuro-protective activities of the alkaloids from U. rhynchophylla were intensively reported. In current work, three new indole alkaloids (1–3), identified as geissoschizic acid (1), geissoschizic acid N 4-oxide (2), and 3β-sitsirikine N 4-oxide (3), as well as 26 known analogues were isolated from U. rhynchophylla. However, in the ne...

Optimisation of the enantioselective biocatalytic hydrolysis of naproxen ethyl ester using ChiroCLEC-CR

CSIR Research Space (South Africa)

Brady, D

2004-03-04

Full Text Available In a biocatalytic reaction the immobilized lipase ChiroCLEC-CR enantioselectively hydrolysed a naproxen ethyl ester racemate, yielding (S)-naproxen with an enantiomeric excess of more than 98%, an enantiomeric ratio (E) of more than 100...

Alkaloids and acetogenins in Annonaceae development: biological considerations

Directory of Open Access Journals (Sweden)

Alma Rosa González-Esquinca

2014-01-01

Full Text Available Chemical studies of the plant family Annonaceae have intensified in the last several decades due to the discovery of annonaceous molecules with medicinal potential (e.g., benzylisoquinoline alkaloids and acetogenins. Approximately 500 alkaloids have been identified in 138 Annonaceae species in 43 genera. In addition, until 2004, 593 annonaceous acetogenins (ACGs had been identified, from 51 species in 13 genera.This suggests that plants from this family allocate important resources to the biosynthesis of these compounds. Despite the diversity of these molecules, their biological roles, including their physiological and/or ecological functions, are not well understood. In this study, it was provided new data describing the variety and distribution of certain alkaloids and ACGs in annonaceous plants in distinct stages of development. The potential relationships among some of these compounds and the seasonally climatic changes occurring in the plant habitat are also discussed. These data will improve our understanding of the secondary metabolism of these pharmacologically important molecules and their expression patterns during development, which will help to determine the optimal growth conditions and harvest times for their production.

Geographic variation in alkaloid production in Conium maculatum populations experiencing differential herbivory by Agonopterix alstroemeriana.

Science.gov (United States)

Castells, Eva; Berhow, Mark A; Vaughn, Steven F; Berenbaum, May R

2005-08-01

Conium maculatum, a Eurasian weed naturalized in North America, contains high concentrations of piperidine alkaloids that act as chemical defenses against herbivores. C. maculatum was largely free from herbivory in the United States, until approximately 30 yr ago, when it was reassociated via accidental introduction with a monophagous European herbivore, the oecophorid caterpillar Agonopterix alstroemeriana. At present, A. alstroemeriana is found in a continuum of reassociation time and intensities with C. maculatum across the continent; in the Pacific Northwest, A. alstroemeriana can cause severe damage, resulting in some cases in complete defoliation. Studies in biological control and invasion biology have yet to determine whether plants reassociated with a significant herbivore from the area of indigeneity increase their chemical defense investment in areas of introduction. In this study, we compared three locations in the United States (New York, Washington, and Illinois) where C. maculatum experiences different levels of herbivory by A. alstroemeriana to determine the association between the intensity of the interaction, as measured by damage, and chemical defense production. Total alkaloid production in C. maculatum was positively correlated with A. alstroemeriana herbivory levels: plants from New York and Washington, with higher herbivory levels, invested two and four times more N to alkaloid synthesis than did plants from Illinois. Individual plants with lower concentrations of alkaloids from a single location in Illinois experienced more damage by A. alstroemeriana, indicative of a preference on the part of the insect for plants with less chemical defense. These results suggest that A. alstroemeriana may act either as a selective agent or inducing agent for C. maculatum and increase its toxicity in its introduced range.

Independent recruitment of a flavin-dependent monooxygenase for safe accumulation of sequestered pyrrolizidine alkaloids in grasshoppers and moths.

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Linzhu Wang

Full Text Available Several insect lineages have developed diverse strategies to sequester toxic pyrrolizidine alkaloids from food-plants for their own defense. Here, we show that in two highly divergent insect taxa, the hemimetabolous grasshoppers and the holometabolous butterflies, an almost identical strategy evolved independently for safe accumulation of pyrrolizidine alkaloids. This strategy involves a pyrrolizidine alkaloid N-oxygenase that transfers the pyrrolizidine alkaloids to their respective N-oxide, enabling the insects to avoid high concentrations of toxic pyrrolizidine alkaloids in the hemolymph. We have identified a pyrrolizidine alkaloid N-oxygenase, which is a flavin-dependent monooxygenase, of the grasshopper Zonocerus variegatus. After heterologous expression in E. coli, this enzyme shows high specificity for pyrrolizidine alkaloids of various structural types and for the tropane alkaloid atropine as substrates, a property that has been described previously for a pyrrolizidine alkaloid N-oxygenase of the arctiid moth Grammia geneura. Phylogenetic analyses of insect flavin-dependent monooxygenase sequences suggest that independent gene duplication events preceded the establishment of this specific enzyme in the lineages of the grasshoppers and of arctiid moths. Two further flavin-dependent monooxygenase sequences have been identified from Z. variegatus sharing amino acid identities of approximately 78% to the pyrrolizidine alkaloid N-oxygenase. After heterologous expression, both enzymes are also able to catalyze the N-oxygenation of pyrrolizidine alkaloids, albeit with a 400-fold lower specific activity. With respect to the high sequence identity between the three Z. variegatus sequences this ability to N-oxygenize pyrrolizidine alkaloids is interpreted as a relict of a former bifunctional ancestor gene of which one of the gene copies optimized this activity for the specific adaptation to pyrrolizidine alkaloid containing food plants.

Independent recruitment of a flavin-dependent monooxygenase for safe accumulation of sequestered pyrrolizidine alkaloids in grasshoppers and moths.

Science.gov (United States)

Wang, Linzhu; Beuerle, Till; Timbilla, James; Ober, Dietrich

2012-01-01

Several insect lineages have developed diverse strategies to sequester toxic pyrrolizidine alkaloids from food-plants for their own defense. Here, we show that in two highly divergent insect taxa, the hemimetabolous grasshoppers and the holometabolous butterflies, an almost identical strategy evolved independently for safe accumulation of pyrrolizidine alkaloids. This strategy involves a pyrrolizidine alkaloid N-oxygenase that transfers the pyrrolizidine alkaloids to their respective N-oxide, enabling the insects to avoid high concentrations of toxic pyrrolizidine alkaloids in the hemolymph. We have identified a pyrrolizidine alkaloid N-oxygenase, which is a flavin-dependent monooxygenase, of the grasshopper Zonocerus variegatus. After heterologous expression in E. coli, this enzyme shows high specificity for pyrrolizidine alkaloids of various structural types and for the tropane alkaloid atropine as substrates, a property that has been described previously for a pyrrolizidine alkaloid N-oxygenase of the arctiid moth Grammia geneura. Phylogenetic analyses of insect flavin-dependent monooxygenase sequences suggest that independent gene duplication events preceded the establishment of this specific enzyme in the lineages of the grasshoppers and of arctiid moths. Two further flavin-dependent monooxygenase sequences have been identified from Z. variegatus sharing amino acid identities of approximately 78% to the pyrrolizidine alkaloid N-oxygenase. After heterologous expression, both enzymes are also able to catalyze the N-oxygenation of pyrrolizidine alkaloids, albeit with a 400-fold lower specific activity. With respect to the high sequence identity between the three Z. variegatus sequences this ability to N-oxygenize pyrrolizidine alkaloids is interpreted as a relict of a former bifunctional ancestor gene of which one of the gene copies optimized this activity for the specific adaptation to pyrrolizidine alkaloid containing food plants.

Characterization of an enantioselective odorant receptor in the yellow fever mosquito Aedes aegypti.

Directory of Open Access Journals (Sweden)

Jonathan D Bohbot

2009-09-01

Full Text Available Enantiomers differ only in the left or right handedness (chirality of their orientations and exhibit identical chemical and physical properties. In chemical communication systems, enantiomers can be differentially active at the physiological and behavioral levels. Only recently were enantioselective odorant receptors demonstrated in mammals while their existence in insects has remained hypothetical. Using the two-microelectrode voltage clamp of Xenopus oocytes, we show that the yellow fever mosquito, Aedes aegypti, odorant receptor 8 (AaOR8 acts as a chiral selective receptor for the (R-(--enantiomer of 1-octen-3-ol, which in the presence of other kairomones is an attractant used by blood-sucking insects to locate their hosts. In addition to steric constraints, chain length and degree of unsaturation play important roles in this recognition process. This is the first characterization of an enantioselective odorant receptor in insects and the results demonstrate that an OR alone, without helper proteins, can account for chiral specificity exhibited by olfactory sensory neurons (OSNs.

Application of electron ionization mass spectrometry for mulungu alkaloid analysis

International Nuclear Information System (INIS)

Feitosa, Luis Guilherme Pereira; Guaratini, Thais; Lopes, Joao Luis Callegari; Lopes, Norberto Peporine; Bizaro, Aline Cavalli; Silva, Denise Brentan da

2012-01-01

Erythrina verna is a medicinal plant used to calm agitation popularly known as mulungu. We purchased the barks of E. verna from a commercial producer and analyzed the alkaloid fraction of the bark by CG-MS and HRESI-MS. Five erythrinian alkaloids were identified: erysotrine, erythratidine, erythratidinone, epimer, and 11-hydroxyeritratidinone. Here we report the compound 11-hydroxyeritratidinone for the first time as a natural product. (author)

O hydrogen bonds in alkaloids

Indian Academy of Sciences (India)

An overview of general classification scheme, medicinal importance and crystal structure analysis with emphasis on the role of hydrogen bonding in some alkaloids is presented in this paper. The article is based on a general kind of survey while crystallographic analysis and role of hydrogen bonding are limited to only ...

Interactions between {beta}-carboline alkaloids and bovine serum albumin: Investigation by spectroscopic approach

Energy Technology Data Exchange (ETDEWEB)

Nafisi, Shohreh, E-mail: drshnafisi@gmail.com [Department of Chemistry, Islamic Azad University, Central Tehran Branch (IAUCTB), Tehran (Iran, Islamic Republic of); Panahyab, Ataollah [Department of Chemistry, Islamic Azad University, Central Tehran Branch (IAUCTB), Tehran (Iran, Islamic Republic of); Bagheri Sadeghi, Golshan [Department of Biology, Islamic Azad University, Science and Research Branch, Tehran (Iran, Islamic Republic of)

2012-09-15

{beta}-Carboline alkaloids are present in medicinal plants such as Peganum harmala L. that have been used as folk medicine in anticancer therapy. BSA is the major soluble protein constituent of the circulatory system, and has many physiological functions including the transport of a variety of compounds. This study is the first attempt to investigate the binding of {beta}-carboline alkaloids to BSA by using a constant protein concentration and varying drug concentrations at pH 7.2. FTIR and UV-Vis spectroscopic methods were used to analyze the binding modes of {beta}-carboline alkaloids, the binding constants and the effects of drug complexation on BSA stability and conformation. Spectroscopic evidence showed that {beta}-carboline alkaloids bind BSA via hydrophobic interaction and van der Waals contacts along with H-bonding with the -NH groups, with overall binding constants of K{sub harmine-BSA}=2.04 Multiplication-Sign 10{sup 4} M{sup -1}, K{sub tryptoline-BSA}=1.2 Multiplication-Sign 10{sup 4} M{sup -1}, K{sub harmaline-BSA}=5.04 Multiplication-Sign 10{sup 3} M{sup -1}, K{sub harmane-BSA}=1.41 Multiplication-Sign 10{sup 3} M{sup -1} and K{sub harmalol-BSA}=1.01 Multiplication-Sign 10{sup 3} M{sup -1}, assuming that there is one drug molecule per protein. The BSA secondary structure was altered with a major decrease of {alpha}-helix from 64% (free protein) to 59% (BSA-harmane), 56% (BSA-harmaline and BSA-harmine), 55% (BSA-tryptoline), 54% (BSA-harmalol) and {beta}-sheet from 15% (free protein) to 6-8% upon {beta}-carboline alkaloids complexation, inducing a partial protein destabilization. - Highlights: Black-Right-Pointing-Pointer We model the binding of {beta}-carboline alkaloids to BSA by using the spectroscopic methods. Black-Right-Pointing-Pointer We investigate the effects of drug complexation on BSA stability and conformation. Black-Right-Pointing-Pointer A partial protein destabilization occurred at high alkaloids concentration. Black

Kinetic Resolution of sec-Thiols by Enantioselective Oxidation with Rationally Engineered 5-(Hydroxymethyl)furfural Oxidase.

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Pickl, Mathias; Swoboda, Alexander; Romero, Elvira; Winkler, Christoph K; Binda, Claudia; Mattevi, Andrea; Faber, Kurt; Fraaije, Marco W

2018-03-05

Various flavoprotein oxidases were recently shown to oxidize primary thiols. Herein, this reactivity is extended to sec-thiols by using structure-guided engineering of 5-(hydroxymethyl)furfural oxidase (HMFO). The variants obtained were employed for the oxidative kinetic resolution of racemic sec-thiols, thus yielding the corresponding thioketones and nonreacted R-configured thiols with excellent enantioselectivities (E≥200). The engineering strategy applied went beyond the classic approach of replacing bulky amino acid residues with smaller ones, as the active site was additionally enlarged by a newly introduced Thr residue. This residue established a hydrogen-bonding interaction with the substrates, as verified in the crystal structure of the variant. These strategies unlocked HMFO variants for the enantioselective oxidation of a range of sec-thiols. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Detection of Pyrrolizidine Alkaloid DNA Adducts in Livers of Cattle Poisoned with Heliotropium europaeum.

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Fu, Peter P; Xia, Qingsu; He, Xiaobo; Barel, Shimon; Edery, Nir; Beland, Frederick A; Shimshoni, Jakob A

2017-03-20

Pyrrolizidine alkaloids are among the most common poisonous plants affecting livestock, wildlife, and humans. Exposure of humans and livestock to toxic pyrrolizidine alkaloids through the intake of contaminated food and feed may result in poisoning, leading to devastating epidemics. During February 2014, 73 mixed breed female beef cows from the Galilee region of Israel were accidently fed pyrrolizidine alkaloid contaminated hay for 42 days, resulting in the sudden death of 24 cows over a period of 63 days. The remaining cows were slaughtered 2.5 months after the last ingestion of the contaminated hay. In this study, we report the histopathological analysis of the livers from five of the slaughtered cows and quantitation of pyrrolizidine alkaloid-derived DNA adducts from their livers and three livers of control cows fed with feed free of weeds producing pyrrolizidine alkaloids. Histopathological examination revealed that the five cows suffered from varying degrees of bile duct proliferation, fibrosis, and megalocytosis. Selected reaction monitoring HPLC-ES-MS/MS analysis indicated that (±)-6,7-dihydro-7-hydroxy-1-hydroxymethyl-5H-pyrrolizine (DHP)-derived DNA adducts were formed in all five livers. The livers from the three control cows did not have any liver damage nor any indication of DHP-DNA adduct formed. These results confirm that the toxicity observed in these cattle was caused by pyrrolizidine alkaloid poisoning and that pyrrolizidine alkaloid-derived DNA adducts could still be detected and quantified in the livers of the chronically poisoned cows 2.5 months after their last exposure to the contaminated feed, suggesting that DHP-derived DNA adducts can serve as biomarkers for pyrrolizidine alkaloid exposure and poisoning.

Peculiarities of tropane alkaloids determination in Datura Stramonium L. leaves

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Володимир Анатолійович Міщенко

2015-12-01

Full Text Available The questions of the search, pharmacological activity and standardization of natural extracts are appropriate and important for national pharmaceutical science and practice. Since 2000, one of the key points of the Action Plan to ensure the integration of Ukraine into the European Union is development of the State Pharmacopoeia of Ukraine harmonized with the European Pharmacopoeia (PhEur.Aim: A comparative analysis of herbal material according to the methods for tropane group alkaloids determination, as described in the PhEur and in the 11th Edition of USSR Pharmacopoeia Monographs «Stramonium leaf».Methods: Datura leaves samples have been harvested during 2010-2012 in different regions of Ukraine for experimental research. Identification of tropane group alkaloids was carried out by the method of thin-layer chromatography (TLC and by Vitali-Morin colour reaction. According to the PhEur method, firstly Dragendorff reagent and then Sodium nitrite solutions were used for the TLC plates spraying. Alkaloids assay was carried out by alkalimetry method with indicator determination of equivalence point.Results: Datura leaves qualitative features, defined by PhEur and the 11th Edition of USSR Pharmacopoeia Monographs «Stramonium leaf», as well as their rationing have been analyzed. Certain differences concerning regulated quality parameters of herbal material have been determined. A comparative analysis of the natural extracts by described in the given normative documents methods for determination of tropane group alkaloids content has been done. After spraying the TLC plates with Sodium nitrite solution, red-brown zones corresponding Hyoscyamine were determined. Hyoscine zones were characterized by less intense color. As a result of quantitative determination it was determined that the alkaloids content in analyzed Datura leaves samples was within the limits regulated by the PhEur and the 11th Edition of USSR Pharmacopoeia – more than 0

Effects of ergot alkaloid exposure on serotonin receptor mRNA in the smooth muscle of the bovine gastrointestinal tract

Science.gov (United States)

Various serotonin (5HT) receptor subtypes have been located in the gastrointestinal tract and some are associated with gut motility. Cattle exposed to ergot alkaloids through consumption of contaminated feedstuffs have demonstrated signs (e.g. - increased rumen DM content and total content) that sug...

Alkaloid-Containing Plants Poisonous to Cattle and Horses in Europe

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Cristina Cortinovis

2015-12-01

Full Text Available Alkaloids, nitrogen-containing secondary plant metabolites, are of major interest to veterinary toxicology because of their occurrence in plant species commonly involved in animal poisoning. Based on epidemiological data, the poisoning of cattle and horses by alkaloid-containing plants is a relatively common occurrence in Europe. Poisoning may occur when the plants contaminate hay or silage or when forage alternatives are unavailable. Cattle and horses are particularly at risk of poisoning by Colchicum autumnale (meadow saffron, Conium maculatum (poison hemlock, Datura stramonium (jimson weed, Equisetum palustre (marsh horsetail, Senecio spp. (ragwort and groundsel and Taxus baccata (European yew. This review of poisonous alkaloid-containing plants describes the distribution of these plants, conditions under which poisoning occurs, active toxic principles involved and subsequent clinical signs observed.

Classification of Opium by UPLC-Q-TOF Analysis of Principal and Minor Alkaloids.

Science.gov (United States)

Liu, Cuimei; Hua, Zhendong; Bai, Yanping

2016-11-01

Opium is the raw material for the production of heroin, and the characterization of opium seizures through laboratory analysis is a valuable tool for law enforcement agencies to trace clandestine opium production and trafficking. In this work, a method for opium profiling based on the relative content of five principal and 14 minor opium alkaloids was developed and validated. UPLC-Q-TOF was adopted in alkaloid analysis for its high selectivity and sensitivity, which facilitated the sample preparation and testing. The authentic sample set consisted of 100 "Myanmar" and 45 "Afghanistan" opium seizures; based on the data set of the 19 alkaloid variables in them, a partial least squares discriminant analysis classification model was successfully achieved. Minor alkaloids were found to be vitally important for opium profiling, although combined use of both principal and minor alkaloids resulted in the best geographical classification result. The developed method realized a simple and accurate way to differentiate opium from Myanmar and Afghanistan, which may find wide application in forensic laboratories. © 2016 American Academy of Forensic Sciences.

Analysis of Amaryllidaceae alkaloids from Zephyranthes grandiflora by GC/MS and their cholinesterase activity

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Lucie Cahlíková

2011-05-01

Full Text Available Amaryllidaceae are known as ornamental plants, furthermore some species of this family contain galanthamine, an acetylcholinesterase inhibitor approved for the treatment of Alzheimer's disease, and other alkaloids with interesting pharmacological activity. The chemical composition of alkaloids from Zephyranthes grandiflora Lindl. was analyzed by GC/MS. Seven known compounds, belonging to five structural types of Amaryllidaceae alkaloids, were identified. The alkaloid extract from the bulbs showed promising cholinesterase inhibitory activities against human blood acetylcholinesterase (HuAChE; IC50 39.2±3.0 µg/mL and human plasma butyrylcholinesterase (HuBuChE; IC50 356±9.3 µg/mL.

Analysis of Amaryllidaceae alkaloids from Zephyranthes grandiflora by GC/MS and their cholinesterase activity

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Lucie Cahlíková

2011-08-01

Full Text Available Amaryllidaceae are known as ornamental plants, furthermore some species of this family contain galanthamine, an acetylcholinesterase inhibitor approved for the treatment of Alzheimer's disease, and other alkaloids with interesting pharmacological activity. The chemical composition of alkaloids from Zephyranthes grandiflora Lindl. was analyzed by GC/MS. Seven known compounds, belonging to five structural types of Amaryllidaceae alkaloids, were identified. The alkaloid extract from the bulbs showed promising cholinesterase inhibitory activities against human blood acetylcholinesterase (HuAChE; IC50 39.2±3.0 µg/mL and human plasma butyrylcholinesterase (HuBuChE; IC50 356±9.3 µg/mL.

A dual Lewis base activation strategy for enantioselective carbene-catalyzed annulations.

Science.gov (United States)

Izquierdo, Javier; Orue, Ane; Scheidt, Karl A

2013-07-24

A dual activation strategy integrating N-heterocyclic carbene (NHC) catalysis and a second Lewis base has been developed. NHC-bound homoenolate equivalents derived from α,β-unsaturated aldehydes combine with transient reactive o-quinone methides in an enantioselective formal [4 + 3] fashion to access 2-benzoxopinones. The overall approach provides a general blueprint for the integration of carbene catalysis with additional Lewis base activation modes.

Temporal and spatial variation in alkaloid levels in Achnatherum robustum, a native grass infected with the endophyte Neotyphodium.

Science.gov (United States)

Faeth, Stanley H; Gardner, Dale R; Hayes, Cinnamon J; Jani, Andrea; Wittlinger, Sally K; Jones, Thomas A

2006-02-01

The native North American perennial grass Achnatherum robustum (Vasey) Barkworth [= Stipa robusta (Vasey) Scribn.] or sleepygrass is toxic and narcotic to livestock. The causative agents are alkaloidal mycotoxins produced from infections by a systemic and asexual Neotyphodium endophyte. Recent studies suggest that toxicity is limited across the range of sleepygrass in the Southwest USA. We sampled 17 populations of sleepygrass with varying distance from one focal population known for its high toxicity levels near Cloudcroft, NM, USA. For some, we sampled individual plants twice within the same growing season and over successive years (2001-2004). We also determined infection levels in each population. In general, all populations were highly infected, but infection levels were more variable near the focal population. Only infected plants within populations near the Cloudcroft area produced alkaloids. The ergot alkaloid, ergonovine, comprised the bulk of the alkaloids, with lesser amounts of lysergic and isolysergic acid amides and ergonovinine alkaloids. Levels of all alkaloids were positively correlated among individual plants within and between growing seasons. Infected plants that produced no alkaloids in 1 yr did not produce any alkaloids within the same growing season or in other years. Levels of alkaloids in sleepygrass populations declined with distance from the Cloudcroft population, although infection levels increased. Infected plants in populations in northern New Mexico and southern Colorado produced no alkaloids at all despite 100% infectivity. Our results suggest that only specific Neotyphodium haplotypes or specific Neotyphodium-grass combinations produce ergot alkaloids in sleepygrass. The Neotyphodium haplotype or host-endophyte combination that produces toxic levels of alkaloids appears restricted to one locality across the range of sleepygrass. Because of the wide variation in alkaloid levels among populations, interactions between the endophyte

Envisaging the Regulation of Alkaloid Biosynthesis and Associated Growth Kinetics in Hairy Roots of Vinca minor Through the Function of Artificial Neural Network.

Science.gov (United States)

Verma, Priyanka; Anjum, Shahin; Khan, Shamshad Ahmad; Roy, Sudeep; Odstrcilik, Jan; Mathur, Ajay Kumar

2016-03-01

Artificial neural network based modeling is a generic approach to understand and correlate different complex parameters of biological systems for improving the desired output. In addition, some new inferences can also be predicted in a shorter time with less cost and labor. As terpenoid indole alkaloid pathway in Vinca minor is very less investigated or elucidated, a strategy of elicitation with hydroxylase and acetyltransferase along with incorporation of various precursors from primary shikimate and secoiridoid pools via simultaneous employment of cyclooxygenase inhibitor was performed in the hairy roots of V. minor. This led to the increment in biomass accumulation, total alkaloid concentration, and vincamine production in selected treatments. The resultant experimental values were correlated with algorithm approaches of artificial neural network that assisted in finding the yield of vincamine, alkaloids, and growth kinetics using number of elicits. The inputs were the hydroxylase/acetyltransferase elicitors and cyclooxygenase inhibitor along with various precursors from shikimate and secoiridoid pools and the outputs were growth index (GI), alkaloids, and vincamine. The approach incorporates two MATLAB codes; GRNN and FFBPNN. Growth kinetic studies revealed that shikimate and tryptophan supplementation triggers biomass accumulation (GI = 440.2 to 540.5); while maximum alkaloid (3.7 % dry wt.) and vincamine production (0.017 ± 0.001 % dry wt.) was obtained on supplementation of secologanin along with tryptophan, naproxen, hydrogen peroxide, and acetic anhydride. The study shows that experimental and predicted values strongly correlate each other. The correlation coefficient for growth index (GI), alkaloids, and vincamine was found to be 0.9997, 0.9980, 0.9511 in GRNN and 0.9725, 0.9444, 0.9422 in FFBPNN, respectively. GRNN provided greater similarity between the target and predicted dataset in comparison to FFBPNN. The findings can provide future

The biology and chemistry of the zoanthamine alkaloids.

Science.gov (United States)

Behenna, Douglas C; Stockdill, Jennifer L; Stoltz, Brian M

2008-01-01

Marine natural products have long played an important role in natural products chemistry and drug discovery. Mirroring the rich variety and complicated interactions of the marine environment, the substances isolated from sea creatures tend to be incredibly diverse in both molecular structure and biological activity. The natural products isolated from the polyps of marine zoanthids are no exception. The zoanthamine alkaloids, the first of which were isolated over 20 years ago, are of particular interest to the synthetic community because they feature a novel structural framework and exhibit a broad range of biological activities. In this Review, we summarize the major contributions to understanding the zoanthamine natural products with regard to their isolation and structure determination, as well as studies on their biological activity and total synthesis.

Aziridino Alcohols as Catalysts for the Enantioselective Addition of Diethylzinc to Aldehydes

DEFF Research Database (Denmark)

Tanner, David Ackland; Kornø, Hanne Tøfting; Guijarro, David

1998-01-01

The chiral aziridino alcohols 1 -3 have been prepared either from amino acids (1a from serine; 1b - 1i and 3 from threonine; 2a - 2e from allo-threonine) or via asymmetric synthesis (1j, 1k, 1l and 2f from methyl cinnamate). These easily available ligands act as catalysts for the enantioselective...

New insights into Vinca alkaloids resistance mechanism and circumvention in lung cancer.

Science.gov (United States)

Zhang, Ying; Yang, Shao-Hui; Guo, Xiu-Li

2017-12-01

Nowadays, lung cancer, as a health problem in worldwide, has high mortality both in men and women. Despite advances in diagnosis and surgical techniques of lung cancer in recent decades, chemotherapy is still a fundamentally and extensively useful strategy. Vinca alkaloids are a class of important and widely used drugs in the treatment of lung cancer, targeting on the Vinca binding site at the exterior of microtubule plus ends. Either intrinsic or acquired resistance to chemotherapy of Vinca alkaloids has been a major obstacle to the treatment of lung cancer, which arose great interests in studies of understanding and overcoming resistance. In this review, we focused on the application and resistance mechanisms of the Vinca alkaloids such as vinblastine, vincristine, vinorelbine and vinflunine in lung cancer. We reviewed characteristic resistance mechanisms in lung cancer including over-expression of ATP-binding cassette (ABC) transporters P-glycoprotein and structural, functional or expression alterations of β-tubulin (βII, βIII, βIV) which may devote to the development of acquired resistance to the Vinca alkaloids; multidrug-resistance proteins (MRP1, MRP2, MRP3) and RLIP76 protein have also been identified that probably play a significant role in intrinsic resistance. Lung resistance-related protein (LRP) is contributed to lung cancer therapy resistance, but is not deal with the Vinca alkaloids resistance in lung cancer. Understanding the principle of the Vinca alkaloids in clinical application and mechanisms of drug resistance will support individualized lung cancer therapy and improve future therapies. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Genotoxic Pyrrolizidine Alkaloids — Mechanisms Leading to DNA Adduct Formation and Tumorigenicity

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Ming W. Chou

2002-09-01

Full Text Available Abstract: Plants that contain pyrrolizidine alkaloids are widely distributed in the world. Although pyrrolizidine alkaloids have been shown to be genotoxic and tumorigenic in experimental animals, the mechanisms of actions have not been fully understood. The results of our recent mechanistic studies suggest that pyrrolizidine alkaloids induce tumors via a genotoxic mechanism mediated by 6,7-dihydro-7-hydroxy-1-hydroxymethyl-5Hpyrrolizine (DHP-derived DNA adduct formation. This mechanism may be general to most carcinogenic pyrrolizidine alkaloids, including the retronecine-, heliotridine-, and otonecinetype pyrrolizidine alkaloids. It is hypothesized that these DHP-derived DNA adducts are potential biomarkers of pyrrolizidine alkaloid tumorigenicity. The mechanisms that involve the formation of DNA cross-linking and endogenous DNA adducts are also discussed.

Hybrid Monoterpenoid Indole Alkaloids Obtained as Artifacts from Rauvolfia tetraphylla.

Science.gov (United States)

Gao, Yuan; Zhou, Dong-Sheng; Hai, Ping; Li, Yan; Wang, Fei

2015-10-01

Five new hybrid monoterpenoid indole alkaloids bearing an unusual 2,2-dimethyl-4-oxopiperidin-6-yl moiety, namely rauvotetraphyllines F-H (1, 3, 4), 17-epi-rauvotetraphylline F (2) and 21-epi-rauvotetraphylline H (5), were isolated from the aerial parts of Rauvolfia tetraphylla. Their structures were established by extensive spectroscopic analysis. The new alkaloids were evaluated for their cytotoxicity in vitro against five human cancer cell lines.

Novel β-Carboline Alkaloid from Peganum Harmala As Antibacterial Agent

International Nuclear Information System (INIS)

Abdel Aziz, H.G.; Abdel Kader, S.M.; El-Sayed, M.M.; EL-Malt, E.A.; Shaker, E.S.

2011-01-01

A novel β-carboline alkaloid isolated from the aerial parts of Peganum harmala L. (Gen: Phyeophylaceae) have been characterized as l-thioformyl-8-β-D-glucopyranoside-bis-2,3-dihydro-isopyridinopyrrol. It is one of β-carboline alkaloids derivatives. The chemical structure was elucidated on the basis of elementary analysis and spectroscopic studies (UV, IR, 1 H-NMR and MS). The isolated compound showed significant antibacterial activity against Streptococcus pyogenus.

Novel {beta}-Carboline Alkaloid from Peganum Harmala As Antibacterial Agent

Energy Technology Data Exchange (ETDEWEB)

Abdel Aziz, H G; Abdel Kader, S M; El-Sayed, M M; EL-Malt, E A; Shaker, E S [Chem. Dept., Fac. Agric., Minia Univ., Minia (Egypt)

2011-07-01

A novel {beta}-carboline alkaloid isolated from the aerial parts of Peganum harmala L. (Gen: Phyeophylaceae) have been characterized as l-thioformyl-8-{beta}-D-glucopyranoside-bis-2,3-dihydro-isopyridinopyrrol. It is one of {beta}-carboline alkaloids derivatives. The chemical structure was elucidated on the basis of elementary analysis and spectroscopic studies (UV, IR, {sup 1}H-NMR and MS). The isolated compound showed significant antibacterial activity against Streptococcus pyogenus.

Dehydropyrrolizidine alkaloid toxicity, cytotoxicity, and carcinogenicity

Science.gov (United States)

Dehyro-pyrrolizidine alkaloid (PA)-containing plants compose about 5% of the world’s flowering plants and they commonly poison livestock, wildlife and humans. Previous work has produced considerable understanding of PA toxicity, species susceptibility, conditions and routes of exposure, toxin metab...

Different effects of clopidogrel and clarithromycin on the enantioselective pharmacokinetics of sibutramine and its active metabolites in healthy subjects.

Science.gov (United States)

Shinde, Dhananjay D; Kim, Ho-Sook; Choi, Jae-Seok; Pan, Wei; Bae, Soo Kyung; Yeo, Chang-Woo; Shon, Ji-Hong; Kim, Dong-Hyun; Shin, Jae Gook

2013-05-01

In this study, we assessed the effects of clopidogrel and clarithromycin, known CYP2B6 and CYP3A inhibitors, respectively, on the enantioselective disposition of racemic sibutramine in conjunction with CYP2B6 polymorphisms in humans. Sibutramine showed enantioselective plasma profiles with consistently higher concentrations of R-enantiomers. Clopidogrel and clarithromycin significantly increased the sibutramine plasma concentration, but their effects differed between enantiomers; a 2.2-fold versus 4.1-fold increase in the AUC in S-enantiomer and 1.8-fold versus 2.0-fold for the R-enantiomer, respectively. The AUCs of S- and R-desmethyl metabolites changed significantly during the clopidogrel phase (P sibutramine was higher in subjects with the CYP2B6*6/*6 genotype, but no statistical difference was observed among the CYP2B6 genotypes. These results suggest that the enantioselective disposition of sibutramine and its active metabolites are influenced by the altered genetic and environmental factors of CYP2B6 and CYP3A activity in vivo. © The Author(s) 2013.

Anti-inflammatory Activity of Pyrrolizidine Alkaloids from the Leaves of Madhuca pasquieri (Dubard).

Science.gov (United States)

Hoang, Le Son; Tran, Manh Hung; Lee, Joo Sang; To, Dao Cuong; Nguyen, Van Thu; Kim, Jeong Ah; Lee, Jeong Hyung; Woo, Mi Hee; Min, Byung Sun

2015-01-01

A novel pyrrolizidine alkaloids, madhumidine A (1), and two known alkaloids, lindelofidine benzoic acid ester (2) and minalobine B (3) were isolated from the leaves of Madhuca pasquieri (Dubard) H. J. LAM. The chemical structures of these alkaloids were established mainly by NMR techniques and mass spectrometry. Their anti-inflammatory activity was evaluated against lipopolysaccharide-induced nitric oxide production in macrophage RAW264.7 cell. In addition, the cytotoxic activity of all isolated compounds was tested against a panel of cancer cell lines.

Soil-borne microorganisms and soil-type affect pyrrolizidine alkaloids in Jacobaea vulgaris

NARCIS (Netherlands)

Joosten, L.; Mulder, P.P.J.; Klinkhamer, P.G.L.; Van Veen, J.A.

2009-01-01

Secondary metabolites like pyrrolizidine alkaloids (PAs) play a crucial part in plant defense. We studied the effects of soil-borne microorganisms and soil-type on pyrrolizidine alkaloids in roots and shoots of Jacobaea vulgaris. We used clones of two genotypes from a dune area (Meijendel),

Enantioselective Collision-Activated Dissociation of Gas-Phase Tryptophan Induced by Chiral Recognition of Protonated l-Alanine Peptides

Science.gov (United States)

Fujihara, Akimasa; Matsuyama, Hiroki; Tajiri, Michiko; Wada, Yoshinao; Hayakawa, Shigeo

2017-06-01

Enantioselective dissociation in the gas phase is important for enantiomeric enrichment and chiral transmission processes in molecular clouds regarding the origin of homochirality in biomolecules. Enantioselective collision-activated dissociation (CAD) of tryptophan (Trp) and the chiral recognition ability of l-alanine peptides ( l-Ala n ; n = 2-4) were examined using a linear ion trap mass spectrometer. CAD spectra of gas-phase heterochiral H+( d-Trp)( l-Ala n ) and homochiral H+( l-Trp)( l-Ala n ) noncovalent complexes were obtained as a function of the peptide size n. The H2O-elimination product was observed in CAD spectra of both heterochiral and homochiral complexes for n = 2 and 4, and in homochiral H+( l-Trp)( l-Ala3), indicating that the proton is attached to the l-alanine peptide, and H2O loss occurs from H+( l-Ala n ) in the noncovalent complexes. H2O loss did not occur in heterochiral H+( d-Trp)( l-Ala3), where NH3 loss and (H2O + CO) loss were the primary dissociation pathways. In heterochiral H+( d-Trp)( l-Ala3), the protonation site is the amino group of d-Trp, and NH3 loss and (H2O + CO) loss occur from H+( d-Trp). l-Ala peptides recognize d-Trp through protonation of the amino group for peptide size n = 3. NH3 loss and (H2O + CO) loss from H+( d-Trp) proceeds via enantioselective CAD in gas-phase heterochiral H+( d-Trp)( l-Ala3) at room temperature, whereas l-Trp dissociation was not observed in homochiral H+( l-Trp)( l-Ala3). These results suggest that enantioselective dissociation induced by chiral recognition of l-Ala peptides through protonation could play an important role in enantiomeric enrichment and chiral transmission processes of amino acids.

Incorporation of 2H-labelled cadaverines into the quinolizidine alkaloids in Baptisia australis

International Nuclear Information System (INIS)

Robins, D.J.; Sheldrake, G.N.

1988-01-01

The incorporation of 2 H-labelled cadaverines into the quinolizidine alkaloids, sparteine and N-methylcytisine, in Baptisia australis has been studied in order to gain more information about the formation of these alkaloids. (author)

Enantioanalysis of S-deprenyl using enantioselective, potentiometric membrane electrodes based on C60 derivatives

International Nuclear Information System (INIS)

Stefan-van Staden, Raluca-Ioana

2010-01-01

Enantioselective, potentiometric membrane electrodes based on (1,2-methanofullerene C 60 )-61-carboxylic acid, diethyl (1,2-methanofullerene C 60 )-61-61-dicarboxylate and tert-butyl (1,2-methanofullerene C 60 )-61-carboxylic acid were proposed for the enantioanalysis of S-deprenyl in pharmaceutical compounds. Molecular modeling calculations were performed to prove the reliability of the proposed electrodes. The different characteristics involved in this analysis were explained, namely (i) the stability of each molecule using total energy, hardness and dipole moment, and (ii) the explanation of the mechanism of interaction using intermolecular forces (moderate hydrogen bond interactions), atomic charges and electrostatic potential. Electronic structures as well as molecular interaction have been investigated using Hartree-Fock theory, 3-21G(*) basis set. Stability and feasibility of all the generated structures were supported by their respective energy minima and fundamental frequencies.

Potential of plant alkaloids as dengue ns3 protease inhibitors: Molecular docking and simulation approach

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Muhammad Tahir ul Qamar

2014-08-01

Full Text Available Dengue infection has become a worldwide health problem and infection rate is increasing each year. Alkaloids are important phytochemicals of medicinal plant and can be used as vaccine candidates for viruses. Therefore, present study was designed to find potential alkaloids inhibitors against the Dengue virus NS2B/NS3 protease which can inhibit the viral replication inside the host cell. Through molecular docking it was investigated that most of the alkaloids bound deeply in the binding pocket of Dengue virus NS2B/NS3 protease and had potential interactions with catalytic triad. Five alkaloids (6’-desmethylthalifaboramin; 3,5-dihydroxythalifaboramine; Betanin; Reserpic acid and Tubulosine successfully blocked the catalytic triad of NS2B/NS3 protease and these alkaloids can serve as a potential drug candidate to stop viral replication. It can be concluded from this study that these alkaloids could serve as important inhibitors to inhibit the replication of DENV and need further in-vitro investigations to confirm their efficacy and drug ability.

Simple Aziridino Alcohols as Chiral Ligands. Enantioselective Additions of Diethylzinc to N-Diphenylphosphinoylimines

DEFF Research Database (Denmark)

Tanner, David Ackland; Andersson, Pher G.; Guijarro, David

1996-01-01

Simple chiral aziridino alcohols 2-5, easily available from L-serine, L-threonine or L-allo-threonine, have been used as ligands to promote the addition of Et(2)Zn to the diphenylphosphinoylimine 1 (Ar=Ph). Enantioselectivities of up to 94% could be obtained by proper choice of the substituents...

Pyrrolizidine Alkaloids: Potential Role in the Etiology of Cancers, Pulmonary Hypertension, Congenital Anomalies, and Liver Disease.

Science.gov (United States)

Edgar, John A; Molyneux, Russell J; Colegate, Steven M

2015-01-20

Large outbreaks of acute food-related poisoning, characterized by hepatic sinusoidal obstruction syndrome, hemorrhagic necrosis, and rapid liver failure, occur on a regular basis in some countries. They are caused by 1,2-dehydropyrrolizidine alkaloids contaminating locally grown grain. Similar acute poisoning can also result from deliberate or accidental consumption of 1,2-dehydropyrrolizidine alkaloid-containing herbal medicines, teas, and spices. In recent years, it has been confirmed that there is also significant, low-level dietary exposure to 1,2-dehydropyrrolizidine alkaloids in many countries due to consumption of common foods such as honey, milk, eggs, salads, and meat. The level of 1,2-dehydropyrrolizidine alkaloids in these foods is generally too low and too intermittent to cause acute toxicity. However, these alkaloids are genotoxic and can cause slowly developing chronic diseases such as pulmonary arterial hypertension, cancers, cirrhosis, and congenital anomalies, conditions unlikely to be easily linked with dietary exposure to 1,2-dehydropyrrolizidine alkaloids, especially if clinicians are unaware that such dietary exposure is occurring. This Perspective provides a comprehensive review of the acute and chronic toxicity of 1,2-dehydropyrrolizidine alkaloids and their potential to initiate certain chronic diseases, and suggests some associative considerations or indicators to assist in recognizing specific cases of diseases that may have resulted from dietary exposure to these hazardous natural substances. If it can be established that low-level dietary exposure to 1,2-dehydropyrrolizidine alkaloids is a significant cause of some of these costly and debilitating diseases, then this should lead to initiatives to reduce the level of these alkaloids in the food chain.

In-silico driven engineering of enantioselectivity of a penicillin G acylase towards active pharmaceutical ingredients

Czech Academy of Sciences Publication Activity Database

Grulich, Michal; Brezovský, J.; Štěpánek, Václav; Palyzová, Andrea; Marešová, Helena; Zahradník, Jiří; Kyslíková, Eva; Kyslík, Pavel

2016-01-01

Roč. 133, Supplement 1 (2016), s. 53-59 ISSN 1381-1177 Institutional support: RVO:61388971 Keywords : Docking experiments * Enantioselectivity * Penicillin G acylase Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 2.269, year: 2016

Stereoselective reactions. XXXII. Enantioselective deprotonation of 4-tert-butylcyclohexanone by fluorine-containing chiral lithium amides derived from 1-phenylethylamine and 1-(1-naphthyl)ethylamine.

Science.gov (United States)

Aoki, K; Koga, K

2000-04-01

Enantioselective deprotonation of 4-tert-butylcyclohexanone was examined using 1-phenylethylamine- and 1-(1-naphthyl)ethylamine-derived chiral lithium amides having an alkyl or a fluoroalkyl substituent at the amide nitrogen. The lithium amides having a 2,2,2-trifluoroethyl group on the amide nitrogen are easily accessible in both enantiomeric forms, and were found to induce good enantioselectivity in the present reaction.

A new spermidine macrocyclic alkaloid isolated from Gymnosporia arenicola leaf.

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da Silva, Gustavo; Martinho, Ana; Soengas, Raquel González; Duarte, Ana Paula; Serrano, Rita; Gomes, Elsa Teixeira; Silva, Olga

2015-10-01

The isolation and structural elucidation of a macrocyclic alkaloid, characterized by the presence of a 13-membered macrolactam ring containing a spermidine unit N-linked to a benzoyl group is hereby reported. The structure of this previously unknown spermidine alkaloid isolated from Gymnosporia arenicola (Celastraceae) leaves has been elucidated by (1)H and (13)C NMR spectroscopy (including bidimensional analysis) and further characterized by high-resolution mass spectrometry and polarimetry. A route for the biosynthesis of this new bioactive macrocycle is proposed and the cytotoxicity of the compound was evaluated against two ATCC cell lines - one normal-derived (MCF10A) and one cancer-derived cell line (MCF7) - using the MTT assay. The alkaloid revealed to be non-cytotoxic against both cell lines. The IC50 values from the cells were also determined. Copyright © 2015 Elsevier B.V. All rights reserved.

Enantioselective analysis of proteinogenic amino acids in cerebrospinal fluid by capillary electrophoresis–mass spectrometry

NARCIS (Netherlands)

Prior, Amir; Sánchez-Hernández, Laura; Sastre-Toraño, Javier; Marina, Maria Luisa; de Jong, Gerhardus J.; Somsen, Govert W.

2016-01-01

d-Amino acids (AAs) are increasingly being recognized as essential molecules in biological systems. Enantioselective analysis of proteinogenic AAs in biological samples was accomplished by CE–MS employing β-CD as chiral selector and ESI via sheath-liquid (SL) interfacing. Prior to analysis, AAs were

Variable Alkaloid Defenses in the Dendrobatid Poison Frog Oophaga pumilio are Perceived as Differences in Palatability to Arthropods.

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Bolton, Sarah K; Dickerson, Kelsie; Saporito, Ralph A

2017-03-01

Conspicuously colored dendrobatid frogs sequester alkaloid defenses from dietary arthropods, resulting in considerable alkaloid variation among populations; however, little is known about how variation is perceived as a defense against predators. Previous studies have found variable alkaloids in the dendrobatid Oophaga pumilio to be associated with differences in toxicity to laboratory mice, suggesting variable defenses are important. Arthropods are natural predators that use chemoreception to detect prey, including frogs, and may therefore perceive variation in alkaloid profiles as differences in palatability. The goal of the present study is to determine how arthropods respond to variable alkaloid defenses in O. pumilio. Frog alkaloids were sampled from individual O. pumilio from ten geographic locations throughout the Bocas del Toro region of Panama and the Caribbean coast of Costa Rica. Alkaloid extracts were used in feeding bioassays with the vinegar fly Drosophila melanogaster and the ant Ectatomma ruidum. Both species of arthropods fed significantly less on frog alkaloid extracts when compared to controls, and differences in alkaloid palatability were observed among frog populations, as well as between sexes and life stages within a population. Differences in alkaloid quantity, richness, and type were the main predictors of arthropod palatability. Our findings also represent the first direct evidence of a palatability spectrum in a vertebrate that sequesters chemical defenses from dietary sources. Further, the presence of a palatability spectrum suggests that variable alkaloid defenses in O. pumilio are ecologically relevant and play an important role in natural predator-prey interactions, particularly with respect to arthropod predators.

Autophagy protects against neural cell death induced by piperidine alkaloids present in Prosopis juliflora (Mesquite).

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Silva, Victor D A; Cuevas, Carlos; Muñoz, Patricia; Villa, Monica; Ahumada-Castro, Ulises; Huenchuguala, Sandro; Santos, Cleonice C Dos; Araujo, Fillipe M DE; Ferreira, Rafael S; Silva, Vanessa B DA; Silva, Juliana H C E; Soares, Érica N; Velozo, Eudes S; Segura-Aguilar, Juan; Costa, Silvia L

2017-01-01

Prosopis juliflora is a shrub that has been used to feed animals and humans. However, a synergistic action of piperidine alkaloids has been suggested to be responsible for neurotoxic damage observed in animals. We investigated the involvement of programmed cell death (PCD) and autophagy on the mechanism of cell death induced by a total extract (TAE) of alkaloids and fraction (F32) from P. juliflora leaves composed majoritary of juliprosopine in a model of neuron/glial cell co-culture. We saw that TAE (30 µg/mL) and F32 (7.5 µg/mL) induced reduction in ATP levels and changes in mitochondrial membrane potential at 12 h exposure. Moreover, TAE and F32 induced caspase-9 activation, nuclear condensation and neuronal death at 16 h exposure. After 4 h, they induced autophagy characterized by decreases of P62 protein level, increase of LC3II expression and increase in number of GFP-LC3 cells. Interestingly, we demonstrated that inhibition of autophagy by bafilomycin and vinblastine increased the cell death induced by TAE and autophagy induced by serum deprivation and rapamycin reduced cell death induced by F32 at 24 h. These results indicate that the mechanism neural cell death induced by these alkaloids involves PCD via caspase-9 activation and autophagy, which seems to be an important protective mechanism.

Autophagy protects against neural cell death induced by piperidine alkaloids present in Prosopis juliflora (Mesquite

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VICTOR D.A. SILVA

Full Text Available ABSTRACT Prosopis juliflora is a shrub that has been used to feed animals and humans. However, a synergistic action of piperidine alkaloids has been suggested to be responsible for neurotoxic damage observed in animals. We investigated the involvement of programmed cell death (PCD and autophagy on the mechanism of cell death induced by a total extract (TAE of alkaloids and fraction (F32 from P. juliflora leaves composed majoritary of juliprosopine in a model of neuron/glial cell co-culture. We saw that TAE (30 µg/mL and F32 (7.5 µg/mL induced reduction in ATP levels and changes in mitochondrial membrane potential at 12 h exposure. Moreover, TAE and F32 induced caspase-9 activation, nuclear condensation and neuronal death at 16 h exposure. After 4 h, they induced autophagy characterized by decreases of P62 protein level, increase of LC3II expression and increase in number of GFP-LC3 cells. Interestingly, we demonstrated that inhibition of autophagy by bafilomycin and vinblastine increased the cell death induced by TAE and autophagy induced by serum deprivation and rapamycin reduced cell death induced by F32 at 24 h. These results indicate that the mechanism neural cell death induced by these alkaloids involves PCD via caspase-9 activation and autophagy, which seems to be an important protective mechanism.

Hybrid Monoterpenoid Indole Alkaloids Obtained as Artifacts from Rauvolfia tetraphylla

OpenAIRE

Gao, Yuan; Zhou, Dong-Sheng; Hai, Ping; Li, Yan; Wang, Fei

2015-01-01

Abstract Five new hybrid monoterpenoid indole alkaloids bearing an unusual 2,2-dimethyl-4-oxopiperidin-6-yl moiety, namely rauvotetraphyllines F–H (1, 3, 4), 17-epi-rauvotetraphylline F (2) and 21-epi-rauvotetraphylline H (5), were isolated from the aerial parts of Rauvolfia tetraphylla. Their structures were established by extensive spectroscopic analysis. The new alkaloids were evaluated for their cytotoxicity in vitro against five human cancer cell lines. Graphical Abstract Electronic supp...

Pyrrolizidine alkaloids from Heliotropium transoxanum Bunge

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M. R. Delnavazi

2016-02-01

Full Text Available Background and objectives: The plants belonging to the genus Heliotropium L. (Boraginaceae are the main sources of toxic pyrrolizidine alkaloids (PAs. In the present study, we have investigated the PAs of the aerial parts of Heliotropium transoxanum Bunge, a perennial species native to Iran. Methods: Silica gel column chromatography and silica gel PTLC were applied for the isolation of PAs present in the total methanol extract of H. transoxanum. The structures of the isolated compounds were identified using 1H-NMR, 13C-NMR and EIMS spectral analyses. Results: Three PAs, heliotrine (1, lasiocarpine (2 and heliotrine N-oxide (3,with known mutagenic and genotoxic properties, were isolated from the aerial parts of H. transoxanum. Conclusion: The results of this study on the presence of toxic PAs in H. transoxanum introduce this herb as a poisonous species and also suggest it as an appropriate source for the isolation of heliotrine and lasiocarpine for further toxicological and pharmacological studies.

The Effect of Alkaloidal Fraction from Annona squamosa L. against Pathogenic Bacteria with Antioxidant Activities

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Abdulmushin M. Shami

2017-12-01

Full Text Available Background: Annona squamosa is used in different places such as India as a general tonic to enrich blood, relieve vomiting, cancer, as a vermicide, for skin complaints and also applied to wounds and ulcers. The purpose of the study was to evaluate the antibacterial and antioxidant properties from of the alkaloidal fraction of A. squamosa. Methods: Well diffusion assay, minimum inhibitory concentration and the minimum bactericidal concentration (MBC were used to evaluate antibacterial activity against Staphylococcus aureus, Escherichia coli, Bacillus cereus, Pseudomonas aeruginosa, MRSA and Helicobacter pylori. DPPH and SOD assays were used to evaluate antioxidant activity. LC-MS analysis was used to identify alkaloids and scanning electron microscopy studies that revealed mode of action. Results: Alkaloidal fraction of A. squamosa exhibited significant inhibition against the tested bacteria. Extracted alkaloids from the leaves of A. squamosa showed high level of antioxidant activities. LC-MS analyses of alkaloids of the plant were identified as corydine, sanjoinine, norlaureline, norcodeine, oxanalobine and aporphine in the leaves of A. squamosa. SEM analysis of the interaction of these substances with the bacteria showed morphological changes of cell wall and lysis of the targeted bacterial cells. Conclusions: It could be concluded that the alkaloids isolated from A. squamosa showed good antibacterial and antioxidant activity. The results suggest the alkaloids can be a new source of antimicrobial agents against pathogenic bacteria and antioxidant source.

Full structure assignments of pyrrolizidine alkaloid DNA adducts and mechanism of tumor initiation.

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Zhao, Yuewei; Xia, Qingsu; Gamboa da Costa, Gonçalo; Yu, Hongtao; Cai, Lining; Fu, Peter P

2012-09-17

Pyrrolizidine alkaloid-containing plants are widespread in the world and are probably the most common poisonous plants affecting livestock, wildlife, and humans. Pyrrolizidine alkaloids are among the first chemical carcinogens identified in plants. Previously, we determined that metabolism of pyrrolizidine alkaloids in vivo and in vitro generated a common set of DNA adducts that are responsible for tumor induction. Using LC-ESI/MS/MS analysis, we previously determined that four DNA adducts (DHP-dG-3, DHP-dG-4, DHP-dA-3, and DHP-dA-4) were formed in rats dosed with riddelliine, a tumorigenic pyrrolizidine alkaloid. Because of the lack of an adequate amount of authentic standards, the structures of DHP-dA-3 and DHP-dA-4 were not elucidated, and the structural assignment for DHP-dG-4 warranted further validation. In this study, we developed an improved synthetic methodology for these DNA adducts, enabling their full structural elucidation by mass spectrometry and NMR spectroscopy. We determined that DHP-dA-3 and DHP-dA-4 are a pair of epimers of 7-hydroxy-9-(deoxyadenosin-N(6)-yl) dehydrosupinidine, while DHP-dG-4 is 7-hydroxy-9-(deoxyguanosin-N(2)-yl)dehydrosupinidine, an epimer of DHP-dG-3. With the structures of these DNA adducts unequivocally elucidated, we conclude that cellular DNA preferentially binds dehydropyrrolizidine alkaloid, for example, dehydroriddelliine, at the C9 position of the necine base, rather than at the C7 position. We also determined that DHP-dA-3 and DHP-dA-4, as well as DHP-dG-3 and DHP-dG-4, are interconvertible. This study represents the first report with detailed structural assignments of the DNA adducts that are responsible for pyrrolizidine alkaloid tumor induction on the molecular level. A mechanism of tumor initiation by pyrrolizidine alkaloids is consequently fully determined.

Differences in Tolerance to Host Cactus Alkaloids in Drosophila koepferae and D. buzzatii

Science.gov (United States)

Soto, Ignacio M.; Carreira, Valeria P.; Corio, Cristian; Padró, Julián; Soto, Eduardo M.; Hasson, Esteban

2014-01-01

The evolution of cactophily in the genus Drosophila was a major ecological transition involving over a hundred species in the Americas that acquired the capacity to cope with a variety of toxic metabolites evolved as feeding deterrents in Cactaceae. D. buzzatii and D. koepferae are sibling cactophilic species in the D. repleta group. The former is mainly associated with the relatively toxic-free habitat offered by prickly pears (Opuntia sulphurea) and the latter has evolved the ability to use columnar cacti of the genera Trichocereus and Cereus that contain an array of alkaloid secondary compounds. We assessed the effects of cactus alkaloids on fitness-related traits and evaluated the ability of D. buzzatii and D. koepferae to exploit an artificial novel toxic host. Larvae of both species were raised in laboratory culture media to which we added increasing doses of an alkaloid fraction extracted from the columnar cactus T. terschekii. In addition, we evaluated performance on an artificial novel host by rearing larvae in a seminatural medium that combined the nutritional quality of O. sulphurea plus amounts of alkaloids found in fresh T. terschekii. Performance scores in each rearing treatment were calculated using an index that took into account viability, developmental time, and adult body size. Only D. buzzatii suffered the effects of increasing doses of alkaloids and the artificial host impaired viability in D. koepferae, but did not affect performance in D. buzzatii. These results provide the first direct evidence that alkaloids are key determinants of host plant use in these species. However, the results regarding the artificial novel host suggest that the effects of alkaloids on performance are not straightforward as D. koepferae was heavily affected. We discuss these results in the light of patterns of host plan evolution in the Drosophila repleta group. PMID:24520377

[Effects of combined use of total alkaloids of Uncaria rhynchophylla and Coryadlis ambailis migo on cerebral ischemia-reperfusion injury in rats].

Science.gov (United States)

Hu, Xue-yong; Sun, An-sheng; Sui, Yu-xia

2007-11-01

To study the effects of combined use of total alkaloids (TA) of Uncaria rhynchophylla (UR) and Coryadlis ambailis migo (CAM) on cerebral ischemia/reperfusion injury in rats. Rat model of middle cerebral artery ischemia/reperfusion was established, the changes of neurological state was scored before and after treatment with the two kinds of TA, single or combined, and the changes of cerebral infarcted volume, cerebral water content, activities of NOS and SOD and content of MDA in rats' brain were estimated as well. After being treated with the combination of both TA, the average neurological score, cerebral infracted volume, cerebral water content, activity of NOS and content of MDA in the model rats significantly decreased, and the activity of SOD was significantly increased (all P < 0.05). The effect of combined use of the two TA was higher than that of use TA of UR or CAM alone (P <0.05). Moreover, the central nervous system inhibitory effect induced by combined TA was significantly weaker than that of UR. Combined use of TA of UR and CAM may facilitate the protection against cerebral ischemia/reperfusion damage, the action mechanism might be relevant to reducing the lipid peroxidation injury of brain cells through inhibiting the NOS activity and increasing the SOD activity.

[Pyrrolizidine alkaloids and seneciosis in farm animals. Part 1: occurrence, chemistry and toxicology].

Science.gov (United States)

Petzinger, E

2011-01-01

Pyrrolizidine alkaloids belong to a class of phytotoxins which are present in more than 6000 plant species. The disease seneciosis in farm animals represents the severe poisoning by pyrrolizidine alkaloids from plants of the genus Senecio. This form of poisoning has been known since the end of the 19th century in Germany, the USA, Canada and New Zealand, and is mainly caused by Senecio jacobaea and related Senecio spp. in farm animals, including poultry. Animal poisoning by pyrrolizidine alkaloids is of worldwide importance. In Germany poisoning of horses and cattle by Senecio jacobaea, which was earlier named Schweinsberg disease, is of renewed relevance for veterinary medicine. The disease occurs almost entirely as a consequence of chronic poisoning and in general ends fatally. The ultimate cause is the formation of toxic metabolites of pyrrolizidine alkaloids in the liver, and their covalent binding to nucleic acids and proteins leading to liver cirrhosis. Because many pyrrolizidine alkaloids possess mutagenic, and a few also carcinogenic properties, European and international authorities are concerned about possible residue levels in food of animal origin. The review addresses in its first part several aspects, being the occurrence, the chemistry, and the toxicology of pyrrolizidine alkaloids as well as animal intoxications by poisonous plants. In the second part (46) clinical characteristics of animal seneciosis, the therapeutic interventions, the significant species differences and a critical assessment of so-called nontoxic amounts of Senecio plants in animal fodder with reference to cumulative lethal toxin doses are presented.

Budd-Chiari syndrome secondary to toxic pyrrolizidine alkaloid exposure.

Science.gov (United States)

Wu, Janet S W; Poon, W T; Ma, C K; Chen, M L; Pang, K S; Mak, Tony W L; Chan, H B

2013-12-01

In this report, we describe a case of pyrrolizidine alkaloid-related Budd-Chiari syndrome in Hong Kong. A 10-month-old boy presented with ascites, right pleural effusion, and hepatomegaly after consumption of herbal drinks for 3 months. His clinical (including imaging) features were compatible with Budd-Chiari syndrome. Budd-Chiari syndrome is a rare disease entity in paediatric patients. In our case, extensive workup performed to look for the underlying cause of Budd-Chiari syndrome was unrevealing, except for toxic pyrrolizidine alkaloid exposure in his herbal drinks.

Enantioselective bioaccumulation of diniconazole in Tenebrio molitor larvae.

Science.gov (United States)

Liu, Chen; LV, Xiao Tian; Zhu, Wen Xue; QU, Hao Yang; Gao, Yong Xin; Guo, Bao Yuan; Wang, Hui Li

2013-12-01

The enantioselective bioaccumulation of diniconazole in Tenebrio molitor Linne larva was investigated with liquid chromatography tandem mass spectrometry based on the ChiralcelOD-3R[cellulose tri-(3,5-dimethylphenyl carbamate)] column. In this study we documented the effects of dietary supplementation with wheat bran contaminated by racemic diniconazole at two dose levels of 20 mg kg(-1) and 2 mg kg(-1) (dry weight) in Tenebrio molitor. The results showed that both doses of diniconazole were taken up by Tenebrio molitor rapidly in the first few days, the concentrations of R-enantiomer and S-enantiomer at high doses reached the highest level of 0.55 mg kg(-1) and 0.48 mg kg(-1) , respectively, on the 1(st) d, and the concentrations of them obtained a maxima of 0.129 mg kg(-1) and 0.128 mg kg(-1) at low dose, respectively, on the 3(rd) d, which means that the concentration of diniconazole was proportional to the time of achieving the highest accumulated level. It afterwards attained equilibrium after a sharp decline at both 20 mg kg(-1) and 2 mg kg(-1) of diniconazole. The determination results from the feces of Tenebrio molitor demonstrated that the extraction recovery (ER) values of the high dose group were higher than that of the low dose group and the values were all above 1; therefore, it could be inferred that enantiomerization existed in Tenebrio molitor. Additionally, the biota accumulation factor was used to evaluate the bioaccumulation of diniconazole enantiomers, showing that the bioaccumulation of diniconazole in Tenebrio molitor was enantioselective with preferential accumulation of S-enantiomer. © 2013 Wiley Periodicals, Inc.

Enantioseparation and determination of the chiral phenylpyrazole insecticide ethiprole in agricultural and environmental samples and its enantioselective degradation in soil

Energy Technology Data Exchange (ETDEWEB)

Zhang, Qing; Shi, Haiyan; Gao, Beibei; Tian, Mingming; Hua, Xiude; Wang, Minghua, E-mail: wangmha@njau.edu.cn

2016-01-15

An effective method for the enantioselective determination of ethiprole enantiomers in agricultural and environmental samples was developed. The effects of solvent extraction, mobile phase and thermodynamic parameters for chiral recognition were fully investigated. Complete enantioseparation of the ethiprole enantiomers was achieved on a Lux Cellulose-2 column. The stereochemical structures of ethiprole enantiomers were also determined, and (R)-(+)-ethiprole was first eluted. The average recoveries were 82.7–104.9% with intra-day RSD of 1.7–8.2% in soil, cucumber, spinach, tomato, apple and peach under optimal conditions. Good linearity (R{sup 2} ≥ 0.9991) was obtained for all the matrix calibration curves within a range of 0.1 to 10 mg L{sup −1}. The limits of detection for both enantiomers were estimated to be 0.008 mg kg{sup −1} in soil, cucumber, spinach and tomato and 0.012 mg kg{sup −1} in apple and peach, which were lower than the maximum residue levels established in Japan. The results indicate that the proposed method is convenient and reliable for the enantioselective detection of ethiprole in agricultural and environmental samples. The behavior of ethiprole in soil was studied under field conditions and the enantioselective degradation was observed with enantiomer fraction values varying from 0.494 to 0.884 during the experiment. The (R)-(+)-ethiprole (t{sub 1/2} = 11.6 d) degraded faster than (S)-(−)-ethiprole (t{sub 1/2} = 34.7 d). This report is the first describe a chiral analytical method and enantioselective behavior of ethiprole, and these results should be extremely useful for the risk evaluation of ethiprole in food and environmental safety. - Highlights: • The ethiprole enantiomers were completely separated. • A novel method for enantioselective determination of ethiprole was developed. • The absolute configurations of ethiprole enantiomers were firstly determined. • The (R)-(+)-ethiprole was preferentially degraded in

Semisynthetic dimers of antiparkinsonic ergot alkaloids

Czech Academy of Sciences Publication Activity Database

Křen, Vladimír; Weignerová, Lenka; Kuzma, Marek; Jegorov, A.; Sedmera, Petr

2001-01-01

Roč. 55, č. 6 (2001), s. 1045-1056 ISSN 0385-5414 R&D Projects: GA AV ČR IAA4020901 Institutional research plan: CEZ:AV0Z5020903 Keywords : ergot alkaloids * antiparkinsonic activity Subject RIV: EE - Microbiology, Virology Impact factor: 0.970, year: 2001

Toxicoproteomic assessment of liver responses to acute pyrrolizidine alkaloid intoxication in rats.

Science.gov (United States)

Li, Yan-Hong; Tai, William Chi-Shing; Khan, Imran; Lu, Cheng; Lu, Yao; Wong, Wing-Yan; Chan, Wood-Yee; Wendy Hsiao, Wen-Luan; Lin, Ge

2018-04-03

A toxicoproteomic study was performed on liver of rats treated with retrorsine (RTS), a representative hepatotoxic pyrrolizidine alkaloid at a toxic dose (140 mg/kg) known to cause severe acute hepatotoxicity. By comparing current data with our previous findings in mild liver lesions of rats treated with a lower dose of RTS, seven proteins and three toxicity pathways of vascular endothelial cell death, which was further verified by observed sinusoidal endothelial cell losses, were found uniquely associated with retrorsine-induced hepatotoxicity. This toxicoproteomic study of acute pyrrolizidine alkaloid intoxication lays a foundation for future investigation to delineate molecular mechanisms of pyrrolizidine alkaloid-induced hepatotoxicity.

Towards a Molecular Understanding of the Biosynthesis of Amaryllidaceae Alkaloids in Support of Their Expanding Medical Use

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Adam M. Takos

2013-05-01

Full Text Available The alkaloids characteristically produced by the subfamily Amaryllidoideae of the Amaryllidaceae, bulbous plant species that include well know genera such as Narcissus (daffodils and Galanthus (snowdrops, are a source of new pharmaceutical compounds. Presently, only the Amaryllidaceae alkaloid galanthamine, an acetylcholinesterase inhibitor used to treat symptoms of Alzheimer’s disease, is produced commercially as a drug from cultivated plants. However, several Amaryllidaceae alkaloids have shown great promise as anti-cancer drugs, but their further clinical development is restricted by their limited commercial availability. Amaryllidaceae species have a long history of cultivation and breeding as ornamental bulbs, and phytochemical research has focussed on the diversity in alkaloid content and composition. In contrast to the available pharmacological and phytochemical data, ecological, physiological and molecular aspects of the Amaryllidaceae and their alkaloids are much less explored and the identity of the alkaloid biosynthetic genes is presently unknown. An improved molecular understanding of Amaryllidaceae alkaloid biosynthesis would greatly benefit the rational design of breeding programs to produce cultivars optimised for the production of pharmaceutical compounds and enable biotechnology based approaches.

Resolution of alpha/beta-amino acids by enantioselective penicillin G acylase from Achromobacter sp

Czech Academy of Sciences Publication Activity Database

Grulich, Michal; Brezovský, J.; Štěpánek, Václav; Palyzová, Andrea; Kyslíková, Eva; Kyslík, Pavel

2015-01-01

Roč. 122, DEC 2015 (2015), s. 240-247 ISSN 1381-1177 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61388971 Keywords : Penicillin G acylase * Enantioselectivity * Homologous model Subject RIV: CE - Biochemistry Impact factor: 2.189, year: 2015

DNA-Accelerated Copper Catalysis of Friedel-Crafts Conjugate Addition/Enantioselective Protonation Reactions in Water

NARCIS (Netherlands)

García-Fernández, Almudena; Megens, Rik P.; Villarino, Lara; Roelfes, Gerard

2016-01-01

DNA-induced rate acceleration has been identified as one of the key elements for the success of the DNA-based catalysis concept. Here we report on a novel DNA-based catalytic Friedel-Crafts conjugate addition/enantioselective protonation reaction in water, which represents the first example of a

An ylide transformation of rhodium(I) carbene: enantioselective three-component reaction through trapping of rhodium(I)-associated ammonium ylides by β-nitroacrylates.

Science.gov (United States)

Ma, Xiaochu; Jiang, Jun; Lv, Siying; Yao, Wenfeng; Yang, Yang; Liu, Shunying; Xia, Fei; Hu, Wenhao

2014-11-24

The chiral Rh(I)-diene-catalyzed asymmetric three-component reaction of aryldiazoacetates, aromatic amines, and β-nitroacrylates was achieved to obtain γ-nitro-α-amino-succinates in good yields and with high diastereo- and enantioselectivity. This reaction is proposed to proceed through the enantioselective trapping of Rh(I)-associated ammonium ylides by nitroacrylates. This new transformation represents the first example of Rh(I)-carbene-induced ylide transformation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Enantioselective organo-photocatalysis mediated by atropisomeric thiourea derivatives.

Science.gov (United States)

Vallavoju, Nandini; Selvakumar, Sermadurai; Jockusch, Steffen; Sibi, Mukund P; Sivaguru, Jayaraman

2014-05-26

Can photocatalysis be performed without electron or energy transfer? To address this, organo-photocatalysts that are based on atropisomeric thioureas and display lower excited-state energies than the reactive substrates have been developed. These photocatalysts were found to be efficient in promoting the [2+2] photocycloaddition of 4-alkenyl-substituted coumarins, which led to the corresponding products with high enantioselectivity (77-96% ee) at low catalyst loading (1-10 mol%). The photocatalytic cycle proceeds by energy sharing via the formation of both static and dynamic complexes (exciplex formation), which is aided by hydrogen bonding. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Combined experimental and theoretical study of the mechanism and enantioselectivity of palladium-catalyzed intermolecular Heck coupling

DEFF Research Database (Denmark)

Henriksen, Signe Teuber; Norrby, Per-Ola; Kaukoranta, Päivi

2008-01-01

. The steric interactions in this transition state fully account for the enantioselectivity observed with the ligands studied. The calculations also predict relative reactivity and nonlinear mixing effects for the investigated ligands; these predictions are fully validated by experimental testing. Finally......The asymmetric Heck reaction using P,N-ligands has been studied by a combination of theoretical and experimental methods. The reaction follows Halpern-style selectivity; that is, the major isomer is produced from the least favored form of the pre-insertion intermediate. The initially formed Ph......, the low conversion observed with some catalysts was found to be caused by inactivation due to weak binding of the ligand to Pd(0). Adding monodentate PPh3 alleviated the precipitation problem without deteriorating the enantioselectivity and led to one of the most effective catalytic systems to date....

Recognition of pyrrolizidine alkaloid esters in the invasive aquatic plant Gymnocoronis spilanthoides (Asteraceae)

Science.gov (United States)

Introduction – The freshwater aquatic plant Gymnocoronis spilanthoides (Senegal tea plant, jazmín del bañado, Falscher Wasserfreund) is an invasive plant in many countries. Behavioural observations of pyrrolizidine alkaloid-pharmacophagous butterflies suggested the presence of pyrrolizidine alkaloid...

Enantioselective N-Heterocyclic Carbene Catalysis via the Dienyl Acyl Azolium.

Science.gov (United States)

Gillard, Rachel M; Fernando, Jared E M; Lupton, David W

2018-04-16

Herein we report the enantioselective N-heterocyclic carbene catalyzed (4+2) annulation of the dienyl acyl azolium with enolates. The reaction exploits readily accessible acyl fluorides and TMS enol ethers to give a range of highly enantio- and diastereo-enriched cyclohexenes (most >97:3 er and >20:1 dr). The reaction was found to require high nucleophilicity NHC catalysts with mechanistic studies supporting a stepwise 1,6-addition/β-lactonization. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Aporphine and tetrahydroprotoberberine alkaloids from the leaves of Guatteria friesiana (Annonaceae) and their cytotoxic activities

International Nuclear Information System (INIS)

Costa, Emmanoel Vilaca; Cruz, Pedro Ernesto O. da; Marques, Francisco A.; Barison, Andersson; Maia, Beatriz Helena L.N.S.; Pinheiro, Maria Lucia B.; Ruiz, Ana Lucia T.G.; Marchetti, Gabriela M.; Carvalho, Joao Ernesto de

2013-01-01

Phytochemical investigation of the leaves of Guatteria friesiana (Annonaceae) afforded three new isoquinoline alkaloids, 13-hydroxy-discretinine, 6,6a-dehydroguatteriopsiscine and 9-dehydroxy-1-methoxy-dihydroguattouregidine. Eight known alkaloids were also isolated, 13-hydroxy-2,3,9,10-tetramethoxyprotoberberine, guatteriopsiscine, lysicamine, liriodenine, atherospermidine, lanuginosine, 7,8-dihydro-8-hydroxypalmatine and palmatine. 13-Hydroxy- 2,3,9,10-tetramethoxyprotoberberine was only obtained by synthesis and is being reported as a natural product for the first time. The structures of the isolated alkaloids were established by extensive analysis of 1D and 2D nuclear magnetic resonance (NMR) and mass spectrometric (MS) data, as well as by comparison with data reported in the literature. The in vitro cytotoxic activity of the major alkaloids was evaluated against tumor and non-tumor cell lines. All of the alkaloids evaluated were determined to be inactive based on National Cancer Institute (NCI/USA) criteria. However, the alkaloid palmatine exhibited a cytostatic effect on MCF-7 (breast) and U251 (glioma) human tumor cell lines, with GI 50 values lower than 20.0 μmol L - 1 (10.5and 16.2μmolL -1 , respectively), suggesting a selective cytotoxic action (author)

Marine Natural Product Bis-indole Alkaloid Caulerpin: Chemistry and Biology.

Science.gov (United States)

Lunagariya, Jignesh; Bhadja, Poonam; Zhong, Shenghui; Vekariya, Rohit; Xu, Shihai

2017-09-27

Marine bis-indole alkaloids comprise a large and increasingly growing class of secondary metabolites, and continue to deliver a great variety of structural templates. The alkaloids derived from marine resources play a crucial role in medicinal chemistry and as chemical agents. In particular, bis-indole alkaloid caulerpin isolated from marine green algae Caulerpa and a red algae Chondria armata at various places around the world, and tested against several therapeutic areas such as anti-diabetic, antinociceptive, anti-inflammatory, anti-tumor, anti-larvicidal, anti-herpes, anti-tubercular, anti-microbial and immunostimulating activity as well as means of other chemical agents. Herein, we summarized discovery of caulerpin, and its potential medicinal and chemical applications in chronological order with various aspects. Additionally, synthesis of caulerpin, its functional analogues, and structural isomer have also been reviewed. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Metabolism of styrene in the human liver in vitro: interindividual variation and enantioselectivity

NARCIS (Netherlands)

Wenker, M. A.; Kezić, S.; Monster, A. C.; de Wolff, F. A.

2001-01-01

1. The interindividual variation and enantioselectivity of the in vitro styrene oxidation by cytochrome P450 have been investigated in 20 human microsomal liver samples. Liver samples were genotyped for the CYP2E1*6 and CYP2E1*5B alleles. 2. Kinetic analysis indicated the presence of at least two

One pot 'click' reactions : tandem enantioselective biocatalytic epoxide ring opening and [3+2] azide alkyne cycloaddition

NARCIS (Netherlands)

Campbell-Verduyn, Lachlan S.; Szymanski, Wiktor; Postema, Christiaan P.; Dierckx, Rudi A.; Elsinga, Philip H.; Janssen, Dick B.; Feringa, Ben L.

2010-01-01

Halohydrin dehalogenase (HheC) can perform enantioselective azidolysis of aromatic epoxides to 1,2-azido alcohols which are subsequently ligated to alkynes producing chiral hydroxy triazoles in a one-pot procedure with excellent enantiomeric excess.

POISONING OF CHICKENS AND DUCKS BY PYRROLIZIDINE ALKALOIDS OF HELIOTROPIUM EUROPAEUM.

Science.gov (United States)

Pass, D A; Hogg, G G; Russell, R G; Edgar, J A; Tence, I M; Rikard-Bell, L

1979-05-01

The disease produced by feeding chickens and ducks a commercial poultry feed containing heliotrine and lasiocarpine, pyrrolizidine alkaloids of Heliotropium europaeum, is described. Illthrift, ascites and degenerative lesions in the liver were the major findings. Similar lesions occurred in chickens fed a diet containing H. europaeum. The source of the alkaloids in commercial poultry feed was probably the seeds of H. europaeum harvested with wheat.

Enantioselective analysis of citalopram and escitalopram in postmortem blood together with genotyping for CYP2D6 and CYP2C19.

Science.gov (United States)

Carlsson, Björn; Holmgren, Anita; Ahlner, Johan; Bengtsson, Finn

2009-03-01

Citalopram is marketed as a racemate (50:50) mixture of the S(+)-enantiomer and R(-)-enantiomer and the active S(+)-enantiomer (escitalopram) that possess inhibitory effects. Citalopram was introduced in Sweden in 1992 and is the most frequently used antidepressant to date in Sweden. In 2002, escitalopram was introduced onto the Swedish market for treatment of depression and anxiety disorders. The main objective of this study was to investigate S(+)-citalopram [i.e., the racemic drug (citalopram) or the enantiomer (escitalopram)] present in forensic autopsy cases positive for the presence of citalopram in routine screening using a non-enantioselective bioanalytical method. Fifty out of the 270 samples found positive by gas chromatography-nitrogen-phosphorus detection were further analyzed using enantioselective high-performance liquid chromatography. The 50 cases were genotyped for CYP2D6 and CYP2C19, as these isoenzymes are implicated in the metabolism of citalopram and escitalopram. In samples positive for racemic citalopram using the screening method for forensic autopsy cases, up to 20% would have been misinterpreted in the absence of an enantioselective method. An enantioselective method is thus necessary for correct interpretation of autopsy cases, after the enantiomer has been introduced onto the market. The percentage of poor metabolizers was 6% for CYP2D6 and 8% for CYP2C19.

Renieramycins H and I, two novel alkaloids from the sponge Haliclona cribricutis Dendy

Digital Repository Service at National Institute of Oceanography (India)

Parameswaran, P.S.; Naik, C.G.; Kamat, S.Y.; Pramanik, B.N.

The known alkaloid, mimosamycin 1, along with its moon- and di hydroxy derivaties, 4-hydroxy mimosamycin 2 and 1, 4-dihydroxymimosamycin 3 and two new dimeric alkaloids: namely renieramycins H and I 4 and 5 have been isolated from the MeOH extract...

Blood pyrrole-protein adducts as a diagnostic and prognostic index in pyrrolizidine alkaloid-hepatic sinusoidal obstruction syndrome.

Science.gov (United States)

Gao, Hong; Ruan, Jianqing Q; Chen, Jie; Li, Na; Ke, Changqiang Q; Ye, Yang; Lin, Ge; Wang, Jiyao Y

2015-01-01

The diagnosis of hepatic sinusoidal obstruction syndrome (HSOS) induced by pyrrolizidine alkaloids is mainly based on clinical investigation. There is currently no prognostic index. This study evaluated the quantitative measurement of blood pyrrole-protein adducts (PPAs) as a diagnostic and prognostic index for pyrrolizidine alkaloid-induced HSOS. Suspected drug-induced liver injury patients were prospectively recruited. Blood PPAs were quantitatively measured using ultra-performance liquid chromatography-tandem mass spectrometry. Patients' age, sex, biochemistry test results, and a detailed drug history were recorded. The patients were divided into two groups, ie, those with HSOS induced by pyrrolizidine alkaloid-containing drugs and those with liver injury induced by drugs without pyrrolizidine alkaloids. The relationship between herb administration, clinical outcomes, blood sampling time, and blood PPA concentration in pyrrolizidine alkaloid-associated HSOS patients was analyzed using multiple linear regression analysis. Forty patients met the entry criteria, among whom 23 had pyrrolizidine alkaloid-associated HSOS and 17 had liver injury caused by drugs without pyrrolizidine alkaloids. Among the 23 patients with pyrrolizidine alkaloid-associated HSOS, ten recovered, four developed chronic disease, eight died, and one underwent liver transplantation within 6 months after onset. Blood PPAs were detectable in 24 of 40 patients with concentrations from 0.05 to 74.4 nM. Sensitivity and specificity of the test for diagnosis of pyrrolizidine alkaloid-associated HSOS were 100% (23/23) and 94.1% (23/24), respectively. The positive predictive value was 95.8% and the negative predictive value was 100%, whereas the positive likelihood ratio was 23.81. The level of blood PPAs in the severe group (died or received liver transplantation) was significantly higher than that in the recovery/chronicity group (P=0.004). Blood PPAs measured by ultra-performance liquid

Repellence and attraction of Apis mellifera foragers by nectar alkaloids

Directory of Open Access Journals (Sweden)

Hroncová Z.

2016-03-01

Full Text Available Plant secondary metabolites present naturally in nectar, such as alkaloids, may change the behavioural responses of floral visitors and affect pollination. Some studies have shown that nectar containing low concentrations of these secondary metabolites is preferred by honey bee foragers over pure nectar. However, it remains unclear whether this is caused by dependence or addictive behaviour, a simple taste preference, or by other conditions such as self-medication. In our choice experiment, free-flying bees were presented with artificial flowers holding 20% sucrose containing 0.5−50 μg ml−1 of one of the naturally occurring nectar alkaloids - caffeine, nicotine, senecionine, and gelsemine. Nectar uptake was determined by weighing each flower and comparing the weight to that of the control flower. Our experimental design minimized memorizing and marking; despite this, caffeine was significantly preferred at concentrations 0.5−2 μg ml−1 over control nectar; this preference was not observed for other alkaloids. All of the compounds tested were repellent at concentrations above 5 μg ml−1. We confirmed previous reports that bees exhibit a preference for caffeine, and hypothesize that this is not due only to addictive behaviour but is at least partially mediated by taste preference. We observed no significant preference for nicotine or any other alkaloid.

Activity of pyrrolizidine alkaloids against biofilm formation and Trichomonas vaginalis.

Science.gov (United States)

da Silva Negreiros Neto, Themístocles; Gardner, Dale; Hallwass, Fernando; Leite, Ana Jéssica Matias; de Almeida, Camila Guimarães; Silva, Laura Nunes; de Araújo Roque, Alan; de Bitencourt, Fernanda Gobbi; Barbosa, Euzébio Guimarães; Tasca, Tiana; Macedo, Alexandre José; de Almeida, Mauro Vieira; Giordani, Raquel Brandt

2016-10-01

Crotalaria genus belongs to the subfamily Papilionoideae comprising about 600 species spread throughout tropical, neotropical and subtropical regions. In this study, seeds of Crolatalaria pallida were used to the isolation of usaramine, a pyrrolizidine alkaloid. Thus, Pseudomonas aeruginosa and Staphylococcus epidermidis were utilized as strains to test some activities of this alkaloid, such as antibiofilm and antibacterial. Meanwhile, monocrotaline obtained from Crotalaria retusa seeds, was used as the starting material for synthesis of necine base derivatives with anti-Trichomonas vaginalis potential. Alkaloids were characterized by 1D and 2D NMR techniques and GC-MS analysis. Usaramine demonstrated a highlighted antibiofilm activity against S. epidermidis by reducing more than 50% of biofilm formation without killing the bacteria, thus it could be assumed as a prototype for the development of new antibiofilm molecules for pharmaceutical and industrial purposes. Monocrotaline activity against T. vaginalis was evaluated and results indicated inhibition of 80% on parasite growth at 1mg/mL, in addition, neither cytotoxicity against vaginal epithelial cells nor hemolytic activity were observed. On the other hand, retronecine showed no anti-T. vaginalis activity while azido-retronecine was more active than monocrotaline killing 85% of the parasites at 1mg/mL. In conclusion, pyrrolizidine alkaloids are suggested as promising prototypes for new drugs especially for topical use. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Plant-symbiotic fungi as chemical engineers: multi-genome analysis of the clavicipitaceae reveals dynamics of alkaloid loci.

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Christopher L Schardl

Full Text Available The fungal family Clavicipitaceae includes plant symbionts and parasites that produce several psychoactive and bioprotective alkaloids. The family includes grass symbionts in the epichloae clade (Epichloë and Neotyphodium species, which are extraordinarily diverse both in their host interactions and in their alkaloid profiles. Epichloae produce alkaloids of four distinct classes, all of which deter insects, and some-including the infamous ergot alkaloids-have potent effects on mammals. The exceptional chemotypic diversity of the epichloae may relate to their broad range of host interactions, whereby some are pathogenic and contagious, others are mutualistic and vertically transmitted (seed-borne, and still others vary in pathogenic or mutualistic behavior. We profiled the alkaloids and sequenced the genomes of 10 epichloae, three ergot fungi (Claviceps species, a morning-glory symbiont (Periglandula ipomoeae, and a bamboo pathogen (Aciculosporium take, and compared the gene clusters for four classes of alkaloids. Results indicated a strong tendency for alkaloid loci to have conserved cores that specify the skeleton structures and peripheral genes that determine chemical variations that are known to affect their pharmacological specificities. Generally, gene locations in cluster peripheries positioned them near to transposon-derived, AT-rich repeat blocks, which were probably involved in gene losses, duplications, and neofunctionalizations. The alkaloid loci in the epichloae had unusual structures riddled with large, complex, and dynamic repeat blocks. This feature was not reflective of overall differences in repeat contents in the genomes, nor was it characteristic of most other specialized metabolism loci. The organization and dynamics of alkaloid loci and abundant repeat blocks in the epichloae suggested that these fungi are under selection for alkaloid diversification. We suggest that such selection is related to the variable life histories

Lipase-catalyzed highly enantioselective kinetic resolution of boron-containing chiral alcohols.

Science.gov (United States)

Andrade, Leandro H; Barcellos, Thiago

2009-07-16

The first application of enzymes as catalysts to obtain optically pure boron compounds is described. The kinetic resolution of boron-containing chiral alcohols via enantioselective transesterification catalyzed by lipases was studied. Aromatic, allylic, and aliphatic secondary alcohols containing a boronate ester or boronic acid group were resolved by lipase from Candida antartica (CALB), and excellent E values (E > 200) and high enantiomeric excesses (up to >99%) of both remaining substrates and acetylated product were obtained.

Alkaloids from Boophone haemanthoides (Amaryllidaceae)

Czech Academy of Sciences Publication Activity Database

Nair, J. J.; Rárová, L.; Strnad, Miroslav; Bastida, J.; van Staden, J.

2013-01-01

Roč. 8, č. 12 (2013), s. 1705-1710 ISSN 1934-578X Institutional research plan: CEZ:AV0Z50380511 Keywords : Alkaloid * Amaryllidaceae * Boophone haemanthoides Subject RIV: CE - Biochemistry Impact factor: 0.924, year: 2013 http://gateway.isiknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=Alerting&SrcApp=Alerting&DestApp=CCC&DestLinkType=FullRecord&UT=000328588200011

Oxidative stress and production of bioactive monoterpene indole alkaloids: biotechnological implications.

Science.gov (United States)

Matsuura, Hélio Nitta; Rau, Mariana Ritter; Fett-Neto, Arthur Germano

2014-02-01

Monoterpene indole alkaloids (MIAs) encompass plant natural products with important pharmacological relevance. They include the anti-tumoral MIAs found in Catharanthus roseus and Camptotheca acuminata. The often low yields of bioactive alkaloids in plants has prompted research to identify the factors regulating MIA production. Oxidative stress is a general response associated with biotic and abiotic stresses leading to several secondary responses, including elicitation of MIA production. These changes in secondary metabolism may take place directly or via second messengers, such as Ca(2+) and reactive oxygen species (ROS). H2O2 is the main ROS that participates in MIA biosynthesis. This review analyzes the links between oxidative stress, elicitation of bioactive MIA production and their potential roles in antioxidant defense, as well as exploring the implications to developing biotechnological strategies relevant for alkaloid supply.

Alkaloids as important scaffolds in therapeutic drugs for the treatments of cancer, tuberculosis, and smoking cessation.

Science.gov (United States)

Kittakoop, Prasat; Mahidol, Chulabhorn; Ruchirawat, Somsak

2014-01-01

Alkaloid molecules can act, depending on a type of amine functionality present in alkalods, as either hydrogenacceptor or hydrogen-donor for hydrogen bonding that is critically important for the interaction (binding) between targets (enzymes, proteins and receptors) and drugs (ligands). Because of this unique property, alkaloid scaffolds are therefore present in several drugs and lead compounds. This review highlights alkaloid scaffolds in drugs, particularly those recently approved in 2012; it also covers the scaffolds in leads and drug candidates which are in clinical trials and preclinical pipeline. The review focuses on three therapeutic areas including treatments of cancer, tuberculosis, and tobacco cessation. Alkaloid scaffolds in drugs and leads are inspired by those of naturally occurring alkaloids, and these scaffolds include pyridine, piperidine, quinoline, quinolinone, quinazoline, isoquinoline, indole, indolinone, isoindole, isoxazole, imidazole, indazole, thiazole, pyrazole, oxazolidinone, oxadiazole, and benzazepine. In addition to medicinal chemistry aspects, natural products possessing an individual alkaloid scaffold, as well as the mechanism of action of drugs and leads, are also discussed in this review.

Variation in the expression of ergot alkaloids between individual tillers of perennial ryegrass

Science.gov (United States)

Mace, Wade; Lunn, Kristy; Lloyd-West, Catherine

2014-11-01

Epichloë fungal endophytes of cool season grasses are well known to produce a range of alkaloids of benefit to the host. Some of these compounds are advantageous to agriculture due to qualities that promote pasture persistence (e.g. the loline class of alkaloids confer insect protection) while others are detrimental to the wellbeing of grazing livestock. The ergot alkaloids (e.g. ergovaline), produced in ryegrass and tall fescue associations, causes poor animal health in farming regions in many countries around the world and further study is required to improve our knowledge on this class of compounds. Here we present the application of a quantitative LC-MS/MS (liquid chromatography coupled to mass spectrometry) method measuring eight ergot alkaloids (chanoclavine, agroclavine, elymoclavine, lysergol, lysergic acid, ergine, lysergyl alanine, ergovaline) produced by endophyte infected grasses, to monitor levels in individual tillers from multiple plants of a single cultivar of perennial ryegrass (Lolium perenne cv. ‘Grasslands Samson’) infected with a common toxic endophyte strain (Epichloë festucae var. lolii). Monitoring the expression in individual tillers allows an estimation of the variability within a plant (between tillers) as well as between plants. The study showed that there is significant variation in the concentration of the ergot alkaloids between tillers of a single plant, at or exceeding the level of variation observed between individual plants of a population. This result emphasizes the fundamental importance of robust experimental design and sampling procedures when alkaloid expression assessment is required and these need to be rigorously tailored to the hypothesis being tested.

Variation in the expression of ergot alkaloids between individual tillers of perennial ryegrass

Directory of Open Access Journals (Sweden)

Wade Jeffray Mace

2014-11-01

Full Text Available Epichloë fungal endophytes of cool season grasses are well known to produce a range of alkaloids of benefit to the host. Some of these compounds are advantageous to agriculture due to qualities that promote pasture persistence (e.g. the loline class of alkaloids confer insect protection while others are detrimental to the wellbeing of grazing livestock. The ergot alkaloids (e.g. ergovaline, produced in ryegrass and tall fescue associations, causes poor animal health in farming regions in many countries around the world and further study is required to improve our knowledge on this class of compounds. Here we present the application of a quantitative LC-MS/MS (liquid chromatography coupled to mass spectrometry method measuring eight ergot alkaloids (chanoclavine, agroclavine, elymoclavine, lysergol, lysergic acid, ergine, lysergyl alanine, ergovaline produced by endophyte infected grasses, to monitor levels in individual tillers from multiple plants of a single cultivar of perennial ryegrass (Lolium perenne cv. ‘Grasslands Samson’ infected with a common toxic endophyte strain (Epichloë festucae var. lolii. Monitoring the expression in individual tillers allows an estimation of the variability within a plant (between tillers as well as between plants.The study showed that there is significant variation in the concentration of the ergot alkaloids between tillers of a single plant, at or exceeding the level of variation observed between individual plants of a population. This result emphasizes the fundamental importance of robust experimental design and sampling procedures when alkaloid expression assessment is required and these need to be rigorously tailored to the hypothesis being tested.

Independent Recruitment of a Flavin-Dependent Monooxygenase for Safe Accumulation of Sequestered Pyrrolizidine Alkaloids in Grasshoppers and Moths

OpenAIRE

Wang, Linzhu; Beuerle, Till; Timbilla, James; Ober, Dietrich

2012-01-01

Several insect lineages have developed diverse strategies to sequester toxic pyrrolizidine alkaloids from food-plants for their own defense. Here, we show that in two highly divergent insect taxa, the hemimetabolous grasshoppers and the holometabolous butterflies, an almost identical strategy evolved independently for safe accumulation of pyrrolizidine alkaloids. This strategy involves a pyrrolizidine alkaloid N-oxygenase that transfers the pyrrolizidine alkaloids to their respective N-oxide,...

Isolation of alkaloid stachydrin from capparis spinosa L. and her new derivatives

International Nuclear Information System (INIS)

Nurmaganbetov, Zh.S.; Turmukhambetov, A.Zh.; Kazantsev, A.V.; Serperov, K.S.

2005-01-01

Phirrolidine alkaloid stachydrin was isolated from capparis spinosa L. New chemical derivatives of this new alkaloid were synthesized by reactions of halogenation (with bromine) and by reactions with methyl iodine and hydrochloric acid. The structures and composition of obtained compounds were determined on the basis of IR, 1 H NMR spectral data and elemental analysis

Biosynthesis of ergot alkaloids from penicillium commune using response surface methodology (RSM)

International Nuclear Information System (INIS)

Shahid, M. G.; Cheema, T. A.; Baig, S.; Nadeem, M.; Nelofar, R.

2017-01-01

The present study employed the response surface methodology (RSM), a statistical technique, for the identification, screening and optimization of fermentation factors to produce ergot alkaloids under laboratory conditions by Penicillium commune. The static surface culture fermentation technique helped to enhance the production of ergot alkaloids. In the first step Plackett-Burman design (PBD) was used to evaluate the effect of ten factors, including nine ingredients of fermentation medium and one process parameter. It was found that sucrose, yeast extract and FeSO/sub 4/.7H/sub 2/O played the pivotal role in enhancing the yield of ergot alkaloids. In the second step, the effect of concentration levels of sucrose, yeast extract and FeSO/sub 4/.7H/sub 2/O was further optimized using Box-Behnken design (BBD) under the same fermentation conditions. The optimized concentrations of sucrose, yeast extract and FeSO/sub 4/.7H/sub 2/O were 41%, 39% and 0.11% respectively, which significantly enhanced the yield of ergot alkaloids. (author)