The Cytotoxic Principles of<i>Prunella vulgaris, Psychotria serpens</i>, and<i>Hyptis capitata</i>: Ursolic Acid and Related Derivatives¹

Abstract

Bioassay-directed fractionation of the cytotoxic antileukemic extracts of Prunella vulgaris, Psychotria serpens, and Hyptis capitata has led to the isolation of ursolic acid as one of the active principles. Ursolic acid showed significant cytotoxicity in the lymphocytic leukemia cells P-388 and L-1210 as well as the human lung carcinoma cell A-549. It also demonstrated marginal cytotoxicity in the KB and the human colon (HCT-8) and mammary (MCF-7) tumor cells. Esterification of the hydroxyl group at C-3 and the carboxyl group at C-17 led to compounds with decreased cytotoxicity in the human tumor cell lines, but with equivalent or slightly increased activity against the growth of L-1210 and P-388 leukemic cells.