New 30-Noroleanane Triterpenoid Saponins from Holboellia coriacea Diels.

Three new 30-noroleanane triterpenoid saponins, akebonoic acid 28-O-β-d-glucopyranosyl-(1''→6')-β-d-glucopyranosyl ester (1), akebonoic acid 28-O-(6''-O-caffeoyl)-β-d-glucopyranosyl-(1''→6')-β-d-glucopyranosyl ester (Holboelliside A, 2) and 3β,20α,24-trihydroxy-29-norolean-12-en-28-oic acid 3-O-(6'-O-caffeoyl)-β-d-glucopyranoside (Holboelliside B, 3) were isolated from the stems of Holboellia coriacea Diels, together with five known compounds, eupteleasaponin VIII (4), 3α-akebonoic acid (5), quinatic acid (6), 3β-hydroxy-30-norhederagenin (7) and quinatoside A (8). The structures of these compounds were determined on the basis of spectral and chemical evidence. Compounds 1-5 were evaluated for their inhibitory activity against three human tumors HepG2, HCT116 and SGC-7901 cell lines in vitro.