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Meng Q, Moinuddin SGA, Celoy RM, Smith CA, Young RP, Costa MA, Freeman RA, Fukaya M, Kim DN, Cort JR, Hawes MC, van Etten HD, Pandey P, Chittiboyina AG, Ferreira D, Davin LB, Lewis NG. Dirigent isoflavene-forming PsPTS2: 3D structure, stereochemical, and kinetic characterization comparison with pterocarpan-forming PsPTS1 homolog in pea. J Biol Chem 2024; 300:105647. [PMID: 38219818 PMCID: PMC10882141 DOI: 10.1016/j.jbc.2024.105647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 12/21/2023] [Accepted: 01/05/2024] [Indexed: 01/16/2024] Open
Abstract
Pea phytoalexins (-)-maackiain and (+)-pisatin have opposite C6a/C11a configurations, but biosynthetically how this occurs is unknown. Pea dirigent-protein (DP) PsPTS2 generates 7,2'-dihydroxy-4',5'-methylenedioxyisoflav-3-ene (DMDIF), and stereoselectivity toward four possible 7,2'-dihydroxy-4',5'-methylenedioxyisoflavan-4-ol (DMDI) stereoisomers was investigated. Stereoisomer configurations were determined using NMR spectroscopy, electronic circular dichroism, and molecular orbital analyses. PsPTS2 efficiently converted cis-(3R,4R)-DMDI into DMDIF 20-fold faster than the trans-(3R,4S)-isomer. The 4R-configured substrate's near β-axial OH orientation significantly enhanced its leaving group abilities in generating A-ring mono-quinone methide (QM), whereas 4S-isomer's α-equatorial-OH was a poorer leaving group. Docking simulations indicated that the 4R-configured β-axial OH was closest to Asp51, whereas 4S-isomer's α-equatorial OH was further away. Neither cis-(3S,4S)- nor trans-(3S,4R)-DMDIs were substrates, even with the former having C3/C4 stereochemistry as in (+)-pisatin. PsPTS2 used cis-(3R,4R)-7,2'-dihydroxy-4'-methoxyisoflavan-4-ol [cis-(3R,4R)-DMI] and C3/C4 stereoisomers to give 2',7-dihydroxy-4'-methoxyisoflav-3-ene (DMIF). DP homologs may exist in licorice (Glycyrrhiza pallidiflora) and tree legume Bolusanthus speciosus, as DMIF occurs in both species. PsPTS1 utilized cis-(3R,4R)-DMDI to give (-)-maackiain 2200-fold more efficiently than with cis-(3R,4R)-DMI to give (-)-medicarpin. PsPTS1 also slowly converted trans-(3S,4R)-DMDI into (+)-maackiain, reflecting the better 4R configured OH leaving group. PsPTS2 and PsPTS1 provisionally provide the means to enable differing C6a and C11a configurations in (+)-pisatin and (-)-maackiain, via identical DP-engendered mono-QM bound intermediate generation, which PsPTS2 either re-aromatizes to give DMDIF or PsPTS1 intramolecularly cyclizes to afford (-)-maackiain. Substrate docking simulations using PsPTS2 and PsPTS1 indicate cis-(3R,4R)-DMDI binds in the anti-configuration in PsPTS2 to afford DMDIF, and the syn-configuration in PsPTS1 to give maackiain.
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Affiliation(s)
- Qingyan Meng
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA
| | - Syed G A Moinuddin
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA
| | - Rhodesia M Celoy
- School of Plant Sciences, University of Arizona, Tucson, Arizona, USA
| | - Clyde A Smith
- Stanford Synchrotron Radiation Lightsource, Stanford University, Menlo Park, California, USA
| | - Robert P Young
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Michael A Costa
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA
| | - Rachel A Freeman
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA
| | - Masashi Fukaya
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA
| | - Doo Nam Kim
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - John R Cort
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA; Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Martha C Hawes
- School of Plant Sciences, University of Arizona, Tucson, Arizona, USA
| | - Hans D van Etten
- School of Plant Sciences, University of Arizona, Tucson, Arizona, USA
| | - Pankaj Pandey
- National Center for Natural Products Research, School of Pharmacy, University of Mississippi, University, Mississippi, USA
| | - Amar G Chittiboyina
- National Center for Natural Products Research, School of Pharmacy, University of Mississippi, University, Mississippi, USA
| | - Daneel Ferreira
- National Center for Natural Products Research, School of Pharmacy, University of Mississippi, University, Mississippi, USA; Division of Pharmacognosy, Department of BioMolecular Sciences, School of Pharmacy, University of Mississippi, University, Mississippi, USA
| | - Laurence B Davin
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA
| | - Norman G Lewis
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA.
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Afaq S, Kazmi MH, Khan S, Malik A, Fatima I, Inamullah F, Farhad Z, Abbas T, Tareen RB. Armatenols A-C, new antioxidant isoflavanols from Colutea armata. JOURNAL OF ASIAN NATURAL PRODUCTS RESEARCH 2023; 25:103-110. [PMID: 35912906 DOI: 10.1080/10286020.2022.2098727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 12/04/2021] [Accepted: 07/04/2022] [Indexed: 06/15/2023]
Abstract
Armatenols A-C (1-3), new isoflavan-4-ols, have been isolated from the CHCl3-soluble sub-fraction of Colutea armata Hemsl. & Lace, along with two known compounds namely 8-methoxyvestitol (4) and colutequinone (5), reported for the first time from this species. Their structures have been elucidated through spectroscopic techniques including MS, IR, UV, CD, 1 D and 2 D NMR. Compounds 1-2 invariably showed significant antioxidant activity using the methods of 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity (DPPH), Fe3+ reducing antioxidant power (FRAP) assay and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) radical scavenging activity (ABTS).
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Affiliation(s)
- Shagufta Afaq
- Department of Applied Chemistry, University of Karachi, Karachi 75270, Pakistan
| | - Mehdi Hassan Kazmi
- Department of Applied Chemistry, University of Karachi, Karachi 75270, Pakistan
| | - Sadia Khan
- Department of Applied Chemistry, University of Karachi, Karachi 75270, Pakistan
| | - Abdul Malik
- International Centre for Chemical and Biological Sciences, HEJ Research Institute of Chemistry, University of Karachi, Karachi 75270, Pakistan
| | - Itrat Fatima
- International Centre for Chemical and Biological Sciences, HEJ Research Institute of Chemistry, University of Karachi, Karachi 75270, Pakistan
| | - Farah Inamullah
- Department of Applied Chemistry, University of Karachi, Karachi 75270, Pakistan
| | - Zahid Farhad
- Department of Applied Chemistry, University of Karachi, Karachi 75270, Pakistan
| | - Tanveer Abbas
- Department of Microbiology, University of Karachi, Karachi 75270, Pakistan
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Liu XY, Zhang YB, Yang XW, Yang YF, Xu W, Zhao W, Peng KF, Gong Y, Liu NF, Zhang P. Anti-Inflammatory Activity of Some Characteristic Constituents from the Vine Stems of Spatholobus suberectus. Molecules 2019; 24:molecules24203750. [PMID: 31627460 PMCID: PMC6832230 DOI: 10.3390/molecules24203750] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Revised: 10/13/2019] [Accepted: 10/14/2019] [Indexed: 12/13/2022] Open
Abstract
The dried vine stems of Spatholobus suberectus are commonly used in traditional Chinese medicine for treating gynecological and cardiovascular diseases. In this study, five new compounds named spasuberol A (2), homovanillyl-4-oxo-nonanoate (5), spasuberol C (6), spasuberoside A (14), and spasuberoside B (15), together with ten known compounds (1, 3, 4, 7–13), were isolated from the dried vine stems of S. suberectus. Their chemical structures were analyzed using spectroscopic assays. This is the first study interpreting the detailed structural information of 4. The anti-inflammatory activity of these compounds was evaluated by reducing nitric oxide overproduction in RAW264.7 macrophages stimulated by lipopolysaccharide. Compounds 1 and 8–10 showed strong inhibitory activity with half maximal inhibitory concentration (IC50) values of 5.69, 16.34, 16.87, and 6.78 μM, respectively, exhibiting higher activity than the positive drug l-N6-(1-iminoethyl)-lysine (l-NIL) with an IC50 value of 19.08 μM. The IC50 values of inhibitory activity of compounds 2 and 4–6 were 46.26, 40.05, 45.87, and 28.29 μM respectively, which were lower than l-NIL, but better than that of positive drug indomethacin with an IC50 value of 55.44 μM. Quantitative real-time polymerase chain reaction analysis revealed that assayed compounds with good anti-inflammatory activity, such as 1, 6, 9, and 10 at different concentrations, can reduce the messenger RNA (mRNA) expression of some pro-inflammatory cytokines such as tumor necrosis factor α (TNF-α), nitric oxide synthase (iNOS), and cyclooxygenase 2 (COX-2). The anti-inflammatory activity and the possible mechanism of the compounds mentioned in this paper were studied preliminarily.
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Affiliation(s)
- Xiao-Yan Liu
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Natural Medicines, School of Pharmaceutical Sciences, Peking University Health Science Center, Peking University, No. 38, Xueyuan Road, Haidian District, Beijing 100191, China.
| | - You-Bo Zhang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Natural Medicines, School of Pharmaceutical Sciences, Peking University Health Science Center, Peking University, No. 38, Xueyuan Road, Haidian District, Beijing 100191, China.
| | - Xiu-Wei Yang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Natural Medicines, School of Pharmaceutical Sciences, Peking University Health Science Center, Peking University, No. 38, Xueyuan Road, Haidian District, Beijing 100191, China.
| | - Yan-Fang Yang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Natural Medicines, School of Pharmaceutical Sciences, Peking University Health Science Center, Peking University, No. 38, Xueyuan Road, Haidian District, Beijing 100191, China.
| | - Wei Xu
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Natural Medicines, School of Pharmaceutical Sciences, Peking University Health Science Center, Peking University, No. 38, Xueyuan Road, Haidian District, Beijing 100191, China.
| | - Wei Zhao
- Zhuzhou Qianjin Pharmaceutical Co., Ltd., Zhuzhou 412000, China.
| | - Kai-Feng Peng
- Zhuzhou Qianjin Pharmaceutical Co., Ltd., Zhuzhou 412000, China.
| | - Yun Gong
- Zhuzhou Qianjin Pharmaceutical Co., Ltd., Zhuzhou 412000, China.
| | - Ni-Fu Liu
- Zhuzhou Qianjin Pharmaceutical Co., Ltd., Zhuzhou 412000, China.
| | - Peng Zhang
- Zhuzhou Qianjin Pharmaceutical Co., Ltd., Zhuzhou 412000, China.
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Ilhan M, Ali Z, Khan IA, Küpeli Akkol E. A new isoflavane-4-ol derivative from Melilotus officinalis (L.) Pall. Nat Prod Res 2018; 33:1856-1861. [PMID: 29772948 DOI: 10.1080/14786419.2018.1477152] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A new isoflavane derivative, melilofficinaside together with seven other metabolites including coumarin, uridine, methyl-α-d-fructofuranoside, and flavonoid glucosides were isolated from the aerial parts of Melilotus officinalis (L.) Pall.
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Affiliation(s)
- Mert Ilhan
- a Faculty of Pharmacy, Department of Pharmacognosy , Gazi University , Etiler, Ankara , Turkey.,b National Center for Natural Products Research, School of Pharmacy , University of Mississippi , Oxford , MS , USA.,c Faculty of Pharmacy, Department of Pharmacognosy , Yüzüncü Yıl University , Van , Turkey
| | - Zulfiqar Ali
- b National Center for Natural Products Research, School of Pharmacy , University of Mississippi , Oxford , MS , USA
| | - Ikhlas A Khan
- b National Center for Natural Products Research, School of Pharmacy , University of Mississippi , Oxford , MS , USA
| | - Esra Küpeli Akkol
- a Faculty of Pharmacy, Department of Pharmacognosy , Gazi University , Etiler, Ankara , Turkey
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Qin T, Metz P. Enantioselective Synthesis of Isoflavanones by Catalytic Dynamic Kinetic Resolution. Org Lett 2017; 19:2981-2984. [DOI: 10.1021/acs.orglett.7b01218] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Tao Qin
- Fachrichtung Chemie und Lebensmittelchemie,
Organische Chemie I, Technische Universität Dresden, Bergstrasse
66, 01069 Dresden, Germany
| | - Peter Metz
- Fachrichtung Chemie und Lebensmittelchemie,
Organische Chemie I, Technische Universität Dresden, Bergstrasse
66, 01069 Dresden, Germany
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Burapan S, Kim M, Han J. Demethylation of Polymethoxyflavones by Human Gut Bacterium, Blautia sp. MRG-PMF1. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:1620-1629. [PMID: 28211698 DOI: 10.1021/acs.jafc.7b00408] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Polymethoxyflavones (PMFs) were biotransformed to various demethylated metabolites in the human intestine by the PMF-metabolizing bacterium, Blautia sp. MRG-PMF1. Because the newly formed metabolites can have different biological activities, the pathways and regioselectivity of PMF bioconversion were investigated. Using an anaerobic in vitro study, 12 PMFs, 5,7-dimethoxyflavone (5,7-DMF), 5-hydroxy-7-methoxyflavone (5-OH-7-MF), 3,5,7-trimethoxyflavone (3,5,7-TMF), 5-hydroxy-3,7-dimethoxyflavone (5-OH-3,7-DMF), 5,7,4'-trimethoxyflavone (5,7,4'-TMF), 5-hydroxy-7,4'-dimethoxyflavone (5-OH-7,4'-DMF), 3,5,7,4'-tetramethoxyflavone (3,5,7,4'-TMF), 5-hydroxy-3,7,4'-trimethoxyflavone (5-OH-3,7,4'-TMF), 5,7,3',4'-tetramethoxyflavone (5,7,3',4'-TMF), 3,5,7,3',4'-pentamethoxyflavone (3,5,7,3',4'-PMF), 5-hydroxy-3,7,3',4'-tetramethoxyflavone (5-OH-3,7,3',4'-TMF), and 5,3'-dihydroxy-3,7,4'-trimethoxyflavone (5,3'-diOH-3,7,4'-TMF), were converted to chrysin, apigenin, galangin, kaempferol, luteolin, and quercetin after complete demethylation. The time-course monitoring of PMF biotransformations elucidated bioconversion pathways, including the identification of metabolic intermediates. As a robust flavonoid demethylase, regioselectivity of PMF demethylation generally followed the order C-7 > C-4' ≈ C-3' > C-5 > C-3. PMF demethylase in the MRG-PMF1 strain was suggested as a Co-corrinoid methyltransferase system, and this was supported by the experiments utilizing other methyl aryl ether substrates and inhibitors.
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Affiliation(s)
- Supawadee Burapan
- Metalloenzyme Research Group and Department of Integrative Plant Science, Chung-Ang University , Anseong 17546, Korea
| | - Mihyang Kim
- Metalloenzyme Research Group and Department of Integrative Plant Science, Chung-Ang University , Anseong 17546, Korea
| | - Jaehong Han
- Metalloenzyme Research Group and Department of Integrative Plant Science, Chung-Ang University , Anseong 17546, Korea
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Awouafack MD, Tchuenguem RT, Ito T, Dzoyem JP, Tane P, Morita H. A New Isoflavanol from the Fruits ofKotschya strigosa(Fabaceae). Helv Chim Acta 2016. [DOI: 10.1002/hlca.201500508] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Maurice D. Awouafack
- Laboratory of Natural Products Chemistry; Department of Chemistry; Faculty of Science; University of Dschang; P.O. Box 67 Dschang Cameroon
| | - Roland T. Tchuenguem
- Department of Biochemistry; Faculty of Science; University of Dschang; P.O. Box 67 Dschang Cameroon
| | - Takuya Ito
- Institute of Natural Medicine; University of Toyama; 2630-Sugitani Toyama 930-0194 Japan
| | - Jean P. Dzoyem
- Department of Biochemistry; Faculty of Science; University of Dschang; P.O. Box 67 Dschang Cameroon
| | - Pierre Tane
- Laboratory of Natural Products Chemistry; Department of Chemistry; Faculty of Science; University of Dschang; P.O. Box 67 Dschang Cameroon
| | - Hiroyuki Morita
- Institute of Natural Medicine; University of Toyama; 2630-Sugitani Toyama 930-0194 Japan
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9
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Tezuka Y, Morikawa K, Li F, Auw L, Awale S, Nobukawa T, Kadota S. Cytochrome P450 3A4 inhibitory constituents of the wood of Taxus yunnanensis. JOURNAL OF NATURAL PRODUCTS 2011; 74:102-105. [PMID: 21138310 DOI: 10.1021/np100665j] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
From the aqueous extract of the wood of Taxus yunnanensis, which showed cytochrome P450 3A4 (CYP3A4) inhibition, a new isoflavan [(3S,4R)-4'-hydroxy-6,3'-dimethoxyisoflavan-4-ol (1)], a new degraded lignan [2,3-bis(hydroxymethyl)-7-hydroxy-6-methoxy-1-tetralone (2)], and a new lignan [(7R)-7-hydroxytaxiresinol (3)] were isolated, together with nine known lignans. Among the isolates obtained, α-conidendrin (12) showed strong CYP3A4 inhibition with an IC(50) value of 0.2 μM.
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Affiliation(s)
- Yasuhiro Tezuka
- Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
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Poonam, Kumari P, Nagpal R, Chauhan SMS. Formation of hydridocobalt(iii) phthalocyanine by reaction of cobalt(ii) phthalocyanines with sodium borohydride and its reactions with antioxidant isoflavones. NEW J CHEM 2011. [DOI: 10.1039/c1nj20582j] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Absolute configuration-dependent epoxide formation from isoflavan-4-ol stereoisomers by biphenyl dioxygenase of Pseudomonas pseudoalcaligenes strain KF707. Appl Microbiol Biotechnol 2010; 89:1773-82. [PMID: 21063701 DOI: 10.1007/s00253-010-2989-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Revised: 10/26/2010] [Accepted: 10/26/2010] [Indexed: 10/18/2022]
Abstract
Biphenyl dioxygenase from Pseudomonas pseudoalcaligenes strain KF707 expressed in Escherichia coli was found to exhibit monooxygenase activity toward four stereoisomers of isoflavan-4-ol. LC-MS and LC-NMR analyses of the metabolites revealed that the corresponding epoxides formed between C2' and C3' on the B-ring of each isoflavan-4-ol substrate were the sole products. The relative reactivity of the stereoisomers was found to be in the order: (3S,4S)-cis-isoflavan-4-ol > (3R,4S)-trans-isoflavan-4-ol > (3S,4R)-trans-isoflavan-4-ol > (3R,4R)-cis-isoflavan-4-ol and this likely depended upon the absolute configuration of the 4-OH group on the isoflavanols, as explained by an enzyme-substrate docking study. The epoxides produced from isoflavan-4-ols by P. pseudoalcaligenes strain KF707 were further abiotically transformed into pterocarpan, the molecular structure of which is commonly found as part of plant-protective phytoalexins, such as maackiain from Cicer arietinum and medicarpin from Medicago sativa.
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Kim M, Won D, Han J. Absolute configuration determination of isoflavan-4-ol stereoisomers. Bioorg Med Chem Lett 2010; 20:4337-41. [DOI: 10.1016/j.bmcl.2010.06.074] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Revised: 06/11/2010] [Accepted: 06/14/2010] [Indexed: 11/30/2022]
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13
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Kim M, Marsh ENG, Kim SU, Han J. Conversion of (3S,4R)-tetrahydrodaidzein to (3S)-equol by THD reductase: proposed mechanism involving a radical intermediate. Biochemistry 2010; 49:5582-7. [PMID: 20515029 DOI: 10.1021/bi100465y] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
To elucidate the mechanism of (3S)-equol biosynthesis, (2,3,4-d(3))-trans-THD was synthesized and converted to (3S)-equol by THD reductase in Eggerthella strain Julong 732. The position of the deuterium atoms in (3S)-equol was determined by (1)H NMR and (2)H NMR spectroscopy, and the product was identified as (2,3,4(alpha)-d(3))-(3S)-equol. All the deuterium atoms were retained, while the OH group at C-4 was replaced by a hydrogen atom with retention of configuration. To explain the deuterium retention in this stereospecific reduction, we propose a mechanism involving radical intermediates.
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Affiliation(s)
- Mihyang Kim
- Metalloenzyme Research Group and Department of Biotechnology, Chung-Ang University, Anseong 456-756, Korea
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14
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Stereospecific biotransformation of dihydrodaidzein into (3S)-equol by the human intestinal bacterium Eggerthella strain Julong 732. Appl Environ Microbiol 2009; 75:3062-8. [PMID: 19304836 DOI: 10.1128/aem.02058-08] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Stereochemical course of isoflavanone dihydrodaidzein (DHD) reduction into the isoflavan (3S)-equol via tetrahydrodaidzein (THD) by the human intestinal anaerobic bacterium Eggerthella strain Julong 732 was studied. THD was synthesized by catalytic hydrogenation, and each stereoisomer was separated by chiral high-performance liquid chromatography. Circular dichroism spectroscopy was used to elucidate the absolute configurations of four synthetic THD stereoisomers. Rapid racemization of DHD catalyzed by Julong 732 prevented the substrate stereospecificity in the conversion of DHD into THD from being confirmed. The absolute configuration of THD, prepared by reduction of DHD in the cell-free incubation, was assigned as (3R,4S) via comparison of the retention time to that of the authentic THD by chiral chromatography. Dehydroequol (DE) was unable to produce the (3S)-equol both in the cell-free reaction and in the bacterial transformation, negating the possible intermediacy of DE. Finally, the intermediate (3R,4S)-THD was reduced into (3S)-equol by the whole cell, indicating the inversion of stereochemistry at C-3 during the reduction. A possible mechanism accounting for the racemization of DHD and the inversion of configuration of THD during reduction into (3S)-equol is proposed.
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Saleem M, Akhter N, Shaiq Ali M, Nazir M, Riaz N, Moazzam M, Arshad M, Jabbar A. Structure determination of salisomide and salisoflavan, two new secondary metabolites from Salsola imbricata, by 1D and 2D NMR spectroscopy. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2009; 47:263-5. [PMID: 19009575 DOI: 10.1002/mrc.2361] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Chromatographic analysis of the alcoholic extract from Salsola imbricata yielded two new secondary metabolites, salisomide (1) and salisoflavan (2). Their structures were established with the help of spectroscopic techniques including COSY, HMQC and HMBC NMR experiments.
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Affiliation(s)
- Muhammad Saleem
- Department of Chemistry, Baghdad-ul-Jadeed Campus, The Islamia University of Bahawalpur, Pakistan
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Axial Conformation of 3-Methyl-2-butenoyl Group in Pyranocoumarin Ring Endows Biological Activity of (+)-Decursin. B KOREAN CHEM SOC 2008. [DOI: 10.5012/bkcs.2008.29.8.1572] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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