Saponins from Polygala japonica and their effects on a forced swimming test in mice.

Five new triterpenoid saponins, polygalasaponins E (1), F (2), G (3), H (4), and J (5), along with eight known ones (6-13), were isolated from the aerial parts of Polygala japonica. Their structures were established by chemical and spectroscopic means. Forced swimming tests on mice showed that saponins 1 and 4 significantly reduce the immobility status by 58.1% and 51.3% at a dosage of 100 mg/kg administrated orally once daily for 5 days, respectively.