DAMMARANE-TYPE SAPONINS FROM GYNOSTEMA PENTAPHYLLUM AND THEIR CYTOTOXIC ACTIVITY

Abstract

A new dammarane-type saponin, gypenoside VN (1), and a known compound, 3b,20S,21-trihydroxydammar-24-ene 3-O-{[a-L-rhamnopyranosyl(1®2)][b-D-glucopyranosyl(1®3)]-a-L-arabinopyranosyl}-21-O-b-D-glucopyranoside (2), were isolated from the total saponin extract of the whole plants of Gynostemma pentaphyllum. Their structures were elucidated on the basis of spectroscopic and chemical methods. The two compounds exhibited significant cytotoxic activity against four human cancer cell lines, A549 (lung), HT-29 (colon), MCF-7 (breast), and SK-OV-3 (ovary), with IC₅₀ values ranging from 20.2 ± 2.1 to 39.2 ± 3.3 mM. They were weakly active against the U937 (leukemia) cell line with IC₅₀ values of 89.5 ± 4.1 and 93.6 ± 3.2 mM for 1 and 2, respectively. Regarding the HL-60 (acute promyelocytic leukemia) cell line, the two compounds were less active with IC₅₀ values greater than 100 mM