Five new cytotoxic triterpenoid saponins from the roots of Symplocos chinensis

Five new triterpenoid saponins, named symplocososides G-K, were isolated from the roots of Symplocos chinensis. Their structures were elucidated by spectral and chemical methods as symplocososide G, 3 beta-O-{[beta-D-glucopyranosyl(1 -> 2)][alpha-L-arabinofuranosyl(1 -> 4)]-beta-D-(3-O-acetyl)-glucuronopyranosyl}-21 beta-O-[(2Z)-3,7-dimethyl-2,6-octadienoyl]-22 alpha-O-(2-methylbutanoyl)-R-1-barrigenol, symplocososide H, 3 beta-O-{[beta-D-glucopyranosyl(1 -> 2)][alpha-L-arabinofuranosyl(1 -> 4)]-beta-D-(3-O-acetyl)-glucuronopyranosyl)-21 beta-O-[(2E)3,7-dimethyl-2,6-octadienoyl]-22 alpha-O-(2-methylbutanoyl)-R-1-barrigenol, symplocososide 1, 3 beta-O-{[beta-D-glucopyranosyl(1 -> 2)][alpha-L-arabinofuranosyl(1 -> 4)]-beta-D-(3-O-acetyl-6-O-methyl)-glucuronopyranosyl}-21 beta-O-[(2Z)3,7-dimethyl-2,6-octadienoyl]-22 alpha-O-(2-methylbutanoyl)-R-1-barrigenol, symplocososide J, 3 beta-O-{[beta-D-glucopyranosyl(1 -> 2)][alpha-L-arabinofuranosyl(1 -> 4)]-beta-D-(3-O-acetyl)-glucuronopyranosyl}-21 beta-O-[(2Z)3,7-dimethyl-2,6-octadienoyl]-22 alpha-O-benzoyl-R-1-barrigenol, and symplocososide K, 3 beta-O-{[beta-D-glucopyranosyl (1 -> 2)][alpha-L-arabinofuranosyl(1 -> 4)]-beta-D-(3-O-acetyl-6-O-methyl)-glucuronopyranosyl}-21 beta-O-[(2Z)3,7-dimethyl-2,6-octadienoyl]- 22 alpha-O-benzoyI-R-1-barrigenol. Symplocososides G-K showed significant cytotoxicity against cancer cell lines KB, HCT-8, Bel-7402, BGC-823 and A549 with IC50 values ranging from 0.82 mu M to 5.09 mu M, except for symplocososide I against cancer cell lines KB, BGC-823, A549 and symplocososide K against cancer cell line BGC-823 with IC50 values > 10.00 mu M.