A new minor triterpene saponin from kaixin-san prescription.

A new minor oleanane-type saponin, ginsenoside-R(OA) (1), has been isolated from the extract of Kaixin-San, a prescription composed of Panax ginseng and other medicinal herbs, together with 15 known ginsenosides. The structure of 1 was established as 3-O-beta-D-glucopyranosyl-(1-->2)-beta-D-glucuronopyranosyl oleanolic acid 28-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside by chemical and spectroscopic evidence. In addition, the presence of ginsenoside-R(OA) in ginseng was confirmed by HPLC-ESI-MS.