α -Amylase and α -Glucosidase Inhibitory Saponins from Polyscias fruticosa Leaves

Three bisdesmosidic saponins 3-o-[β-d-glucopyranosyl-(1 → 4)-β-d-glucuronopyranosyl] oleanolic acid 28-o-β-d-glucopyranosyl ester (1),polyscioside d (2),and 3-o- { β -d-glucopyranosyl-(1 → 2)-[β-d-glucopyranosyl-(1 → 4)]-β-d- g l u c u r o n o p y r a n o s y l } oleanolic acid 28-o-β-d-glucopyranosyl-(1 → 2)-β-d-galactopyranosyl ester (3) were isolated from a methanol extract of polyscias fruticosa (l.) harms leaves. compound 1 was obtained as a main constituent and compound 3 was reported for the first time and named as polyscioside i. saponin 1 inhibited porcine pancreas α-amylase and yeast α-glucosidase activities while 2 and 3 were inactive. synergistic inhibitory effect on α-amylase was observed from the combination of low concentrations of 1 and acarbose. the findings suggest the use of p. fruticosa and its major saponin 1 for the prevention and treatment of diabetes and its complications. © 2016 tran thi hong hanh et al.