New SIRT1 activator from alkaline hydrolysate of total saponins in the stems-leaves of Panax ginseng

Two new dammarane-type triterpenes, namely ginsenoslaloside-I [3 beta,12 beta,24S-trihydroxy-dammara-20 (22)E, 25-diene-3-O-beta-D-glucopyranoside, 1] and 20(S)-ginsenoside-Rh-1-6'-acetate (2), together with twelve known compounds (3-14) were isolated from the alkaline hydrolysate of total saponins of the stems-leaves of Panax ginseng C. A. Meyer. Their chemical structures were elucidated by extensive spectroscopic analyses and comparison with the reported data. All 14 compounds were evaluated for their anti-proliferative activities against two human cancer cell lines (HL-60 and Hep-G2) and promotion activities of SIRT1. Compound 6 exhibited significant inhibitory activity in a concentration-dependent manner against HL-60 and Hep-G2 with the IC50 values of 10.32 and 24.33 mu M, respectively, and had comparable IC50 values with those of vinorelbine, a positive control agent. Meanwhile, compounds 1 and 6 were found to be a potential activator of SIRT1. The preliminary structure-activity relationship was also discussed based on the experimental data obtained. (C) 2015 Elsevier Ltd. All rights reserved.