Chemical constituents of Morus alba L. and their inhibitory effect on 3T3-L1 preadipocyte proliferation and differentiation.

Mulberry leaf, an important traditional Chinese medicine, possesses many biological activities, including effects of anti-obesity. However, which constituents of mulberry leaf are responsible for its anti-adipogenic action is unclear. This study primarily investigated the chemical constituents from mulberry leaf and their bioactivity on the proliferation and differentiation of 3T3-L1 preadipocytes. A new flavane derivative, (2S)-4'-hydroxy-7-methoxy-8-prenylflavan (1), together with twelve known compounds including three flavanes (2-4), three chalcones (5-7), two flavones (8-9), two benzofurans (10-11) and two coumarin (12-13) was isolated from mulberry leaf. The structure of the new compound was elucidated by various spectroscopic methods including UV, HR-ESI-MS, (1)H and (13)C NMR and CD. The results of activity screening showed that compound 2, 6 and 7 inhibited the proliferation and differentiation of 3T3-L1 preadipocytes.