Synthesis and Tumor Cytotoxicity of Novel N-Substituted Glucosamine-bearing Oleanolic Acid Derivatives

Eleven novel triterpenoid saponins, N-substituted-β-D-glucosaminide derivatives of oleanolic acid, were designed and synthesized via a stepwise glycosylation strategy. These compounds were evaluated for in vitro cytotoxic activity against six different tumor cell lines. Most of the compounds inhibited the growth of, at least, one tumor cell line effectively at micromolar concentrations. Preliminary structure-activity relationships(SARs) indicate that acylation of the nitrogen of the glucosamine-bearing triterpenoid saponins affords the compounds that are highly cytotoxic towards specific tumor cell lines.