The Cytotoxicity of Mimusops Caffra-Derived Ursolic Acid and Its Three Triterpenoid Semi-synthesized Derivatives on HEK293 and HepG2 Cells

Abstract

The isolation of pure ursolic acid (UA) from most plants presents a problem because it often comes as a mixture with its isomer, oleanolic acid (OA). In this study the separation of UA from OA/UA mixture obtained from Mimusops caffra was achieved through acetylation to give the acetate of UA and OA respectively. Pure UA (90%) was then obtained by simple de-acetylation of the UA acetate. The resulting UA was used as template for the semi-synthesis of three triterpenoids derivatives. This study confirmed the various reports in literature that UA is always accompanied by its isomer oleanolic acid (OA). This article further reports for the first time the synthesis of 3-acetyl-UA-28-cinnamate. The cytotoxicity of all compounds was evaluated on human embryonic cells (HEK293) and human hepatocellular carcinoma cells (HepG2) by MTT assay. All the compounds studied exhibited low toxicity levels with IC50 > 300 µg/ml.