Isolation and identification of a cytotoxic principle from Chrysosplenium grayanum Maxim. (Saxifragaceae) and its antitumor activities.

A cytotoxic principle was newly isolated from Chrysosplenium grayanum Maxim. (Saxifragaceae) and identified as beta-peltoboykinolic acid (1) on the basis of spectral data. Cytotoxicity of compound 1 was tested against various human cancer cell lines in vitro, and antitumor effect of this compound was demonstrated on Meth.A mouse fibrosarcoma. The experiment of combined treatment with compound 1, mitomycin C, and OK-432 resulted in enhancing the antitumor effect against B16-BL6 mouse melanoma in C57BL/6 mice.