[Oleanolic acid saponins from the root bark of Aralia taibaiensis]

Five oleanolic acid saponins were isolated from the root bark of Aralia taibaiensis Z.Z. Wang et H.C. Zheng. By spectroscopic and chemical methods, they were identified as araloside A (1), 3-O-[alpha-L-arabinofuranosyl(1-->4)-6'-O-n-butyl-beta-D- glucuronopyranosyl]-oleanolic acid-28-O-beta-D-glucopyranoside (2), 3-O-[alpha-L-arabinofuranosyl(1-->4)-6'-O-ethyl-beta-D- glucuronopyra-nosyl]-oleanolic acid-28-O-beta-D-glucopyranoside (3), stipuleanoside R2(4) and 3-O-(beta-D-glucopyranosyl(1-->3) [alpha-L-arabinofuranosyl(1-->4)]-6'-O-ethyl-beta-D- glucuronopyranosyl)-oleanolic acid-28-O-beta-D-glucopyranoside (5). Saponin 1 and 4 were isolated from the title plant for the first time. 2, 3 and 5 are new compounds and named taibaienoside I, taibaienoside II and taibaienoside III, respectively.