Tyrosinase inhibitory constituents from the stems of Maackia fauriei
Bioassay-guided investigation of the stems of Maackia fauriei led to the isolation of seven flavonoid constituents, formononetin (1), genistein (2), daidzein (3), texasin (4), tectorigenin (5), odoratin (6) and mirkoin (7). Their structures were elucidated on the basis of spectral studies as well as...
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Published in | Phytotherapy research Vol. 24; no. 1; pp. 70 - 75 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
Chichester, UK
John Wiley & Sons, Ltd
01.01.2010
Wiley |
Subjects | |
Online Access | Get full text |
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Summary: | Bioassay-guided investigation of the stems of Maackia fauriei led to the isolation of seven flavonoid constituents, formononetin (1), genistein (2), daidzein (3), texasin (4), tectorigenin (5), odoratin (6) and mirkoin (7). Their structures were elucidated on the basis of spectral studies as well as by comparison with literature data. Tyrosinase inhibition activities were carried out on the isolated compounds. Among these, mirkoin (7) was identified as a potent tyrosinase inhibitor. It inhibited mushroom tyrosinase with an IC₅₀ value of 0.005 mm, which is ten times more active than kojic acid (IC₅₀ = 0.045 mm). The inhibition kinetics, analysed by Lineweaver-Burk plots, indicated mirkoin (7) to be a competitive inhibitor of tyrosinase when l-tyrosinase was used as a substrate. The results suggest that hydroxyl groups at C-4′ in the B ring of flavonoids play an important role in the tyrosinase inhibition activities. Interestingly, compounds 4-7 were isolated for the first time from this plant. Copyright © 2009 John Wiley & Sons, Ltd. |
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Bibliography: | http://dx.doi.org/10.1002/ptr.2870 ark:/67375/WNG-1THNDZTC-R ArticleID:PTR2870 istex:6DC5F46F1B2C08B3B27EB53B96F309F668CCEC6D ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0951-418X 1099-1573 |
DOI: | 10.1002/ptr.2870 |