[Synthesis and anti-tumor activity of ginsenoside Rh_2 caprylic acid monoester].

Ginsenoside Rh_2,firstly isolated from red ginseng,is protopanaxadiol type of steroidal saponin. Rh_2 possessed variety of activities,but bioavailability of oral administration Rh_2 was extremely low due to poor absorption. Moreover,ginsenoside Rh_2 exhibited toxicity on human normal cells. Therefore,to improve stronger anti-tumor activity and attenuate toxicity,it was essential to design and optimize chemical structure of ginsenoside Rh_2. Through n-octanoylchloride modifications,a novel ester derivative of ginsenoside Rh_2 named caprylic acid monoester of Rh_2( C-Rh_2) was designed and synthesized. Structure of novel ginsenoside derivative was identified by1 D and 2 D NMR,as well as ESI-MS analyses. Anti-tumor effect of C-Rh_2 was tested on H22 tumor bearing mice. C-Rh_2 displayed certain anti-tumor activities and exhibited less toxicity than Rh_2. In the present study,C-Rh_2 as ester form of ginsenoside Rh_2 showed better anti-tumor activity and less toxicity,but the specific mechanism needs further investigation.