Triterpenoid saponins with N-acetyl sugar from the bark of Albizia procera.

Abstract Three ( 1 ,  2 ,  4 ) and one known ( 3 ) triterpenoid saponins were isolated from the bark of Albizia procera . The saponins were characterized as 3- O -[β- d -xylopyranosyl-(1 → 2)-α- l -arabinopyranosyl-(1 → 6)-2-acetamido-2-deoxy-β- d -glucopyranosyl] echinocystic acid ( 1 ), 3- O -[α- l -arabinopyranosyl-(1 → 2)-β- d -fucopyranosyl-(1 → 6)-2-acetamido-2-deoxy-β- d -glucopyranosyl] echinocystic acid ( 2 ) and 3- O -[β- d -xylopyranosyl-(1 → 2)-α- l -arabinopyranosyl-(1 → 6)-2-acetamido-2-deoxy-β- d -glucopyranosyl] acacic acid lactone ( 4 ). Their structures were elucidated by 1D and 2D NMR experiments, FABMS as well as chemical means. Saponins 1 and 3 exhibited cytotoxicity against HEPG2 cell line with IC 50 9.13 μg/ml and 10 μg/ml, respectively.