Bellidifolin: a potent hypoglycemic agent in streptozotocin (STZ)-induced diabetic rats from Swertia japonica.

Hypoglycemic activity-guided fractionation led to the isolation of five known xanthones and two triterpenoids from the ethyl acetate soluble fraction of Swertia japonica and their identification was based on spectroscopic methods. One of the triterpenes, thysanolactone, was first isolated from this plant. Among the xanthones, bellidifolin showed a potent and dose-dependent hypoglycemic activity in STZ-induced diabetic rats both in i.p. and p.o. administration. A comparative hypoglycemic activity of the other three xanthones together with bellidifolin was also studied.