Two new triterpene saponins from Gynostemma pentaphyllum

Two new dammarane-type triterpene saponins, gypenbiosides A (1) and B (2), were isolated from the aerial parts of Gynostemma pentaphyllum (Thunb.) Makino. Their structural elucidations were accomplished mainly on the basis of the interrelation of spectroscopic methods, such as IR, HR-TOF-MS, and NMR. The cytotoxic activity was evaluated against one human cancer cell line HL-60 using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.