[摘要]：During the screening effort to discover new types of protein tyrosine phosphatase 1B (PTP1B) inhibitors, it was found that a MeOH extract of the leaves and stems of Weigela subsessilis (Caprifoliaceae) inhibited the enzyme activity. By means of an in vitro bioassay-guided fractionation on the MeOH extract, two 24-norursane triterpenes, ilekudinol A (1) and ilekudinol B (2), were isolated as active metabolites. Compounds 1 and 2 inhibited PTP1B with IC50 values of 29.1 +/- 2.8 and 5.3 +/- 0.5 mu M, respectively. Kinetic studies suggest that both 1 and 2 are non-competitive inhibitors of PTP1B. The findings indicate that the free carboxyl group at C-28 in this type of triterpenes plays a critical role in the inhibition of PTP1B. Copyright (C) 2010 John Wiley & Sons, Ltd.
