Characterization of tyrosinase inhibitors in the twigs of Cudrania tricuspidata and their structure-activity relationship study

The twigs of Cudrania tricuspidata were found to show strong tyrosinase inhibitory activity, and further detailed component analysis resulted in the isolation of a new flavanol glucoside, (2S,3S)-2, 3-trans-dihydromorin-7-O-beta-n-glucoside (1), plus twenty-seven known compounds (2-28). Their structures were elucidated on the basis of ESI-MS and NMR spectral data. Among the isolated compounds, trans-dihydromorin (8), oxyresveratrol (9), and steppogenin (12) were found to exhibit significant tyrosinase inhibition activities. Moreover, the structure-activity relationship of these isolated compounds was also discussed. (c) 2012 Elsevier B.V. All rights reserved.