Two triterpenoid glycosides from the roots of Camellia oleifera and their cytotoxic activity

Two new triterpenoid saponins, oleiferoside N and oleiferoside O, were isolated from the EtOH extract from the roots of Camellia oleifera C. Abel. Their structures were elucidated as 16α-acetoxy-21β,22α-O-diangeloyloxy-23,28-dihydroxyolean-12-ene 3β-O-β-D-xylopyranosyl-(1 → 3)-α-L-arabinopyranosyl-(1 → 3)-β-D-glucuronopyranoside (1), 16α-acetoxy-21β-O-angeloyloxy-23,28-dihydroxy-22α-O-(2-methylbutanoyloxy)olean-12-ene 3β-O-β-D-xylopyranosyl-(1 → 3)-α-L-arabinopyranosyl-(1 → 3)-β-D-glucuronopyranoside (2), on the basis of spectroscopic analyses (IR, ESI-MS, HR-ESI-MS, 1D and 2D NMR) and acid hydrolysis. Both were characterized to be oleanane-type saponins with sugar moieties linked to C-3 of the aglycone. Cytotoxic activities of two saponins were evaluated against four human tumor cell lines (A549, B16, BEL-7402, and MCF-7) by using the MTT in vitro assay. Compounds 1 and 2 showed moderate cytotoxic activities toward the tested cell lines.