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.