Tyrosinase inhibitors from paper mulberry (Broussonetia papyrifera)
2008
Zheng, Z.P. | Cheng, K.W. | Chao, J.F. | Wu, J.J. | Wang, M.F.
Fractionation of a chloroform-soluble extract from twigs of Broussonetia papyrifera, led to the isolation of one new compound, 3,5,7,4'-tetrahydroxy-3'-(2-hydroxy-3-methylbut-3-enyl)flavone (1), and 10 known compounds, uralenol (2), quercetin (3), isolicoflavonol (4), papyriflavonol A (5), broussoflavonol F (6), 5,7,3',5'-tetrahydroxyflavanone (7), luteolin (8), isoliquiritigenin (9), broussochalcone A (10) and 5,7,3',4'-tetrahydroxy-3-methoxyflavone (11). Their structures were identified by interpretation of MS, ¹H NMR, ¹³C NMR, HMQC and HMBC data. Their inhibitory activities on mushroom tyrosinase using l-tyrosine as substrate were investigated and the IC₅₀ values of 3,5,7,4'-tetrahydroxy-3'-(2-hydroxy-3-methylbut-3-enyl)flavone, uralenol, quercetin and broussoflavonol F were found to be 96.6, 49.5, 57.8, and 82.3 μM, respectively, better than arbutin, a well-known tyrosinase inhibitor.
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