Title: Yoshikawa M, et al. Bioactive saponins and glycosides. XVI. Nortriterpene oligoglycosides with gastroprotective activity from the fresh leaves of Euptelea polyandra Sieb. et Zucc. (1): structures of Eupteleasaponins I, II, III, IV, V, and V acetate. Chem Pharm Bull (Tokyo). 2000 Jul;48(7):1045-50.