Pentacyclic triterpenoids oleanolic acid, ursolic acid, betulinic acid, and platanic acid were acetylated and converted into several amides 9-31; the cytotoxicity of which has been determined in sulforhodamine B assays employing seral human tumor cell lines and nonmalignant fibroblasts. Thereby, a betulinic acid/trans-1,4-cyclohexyldiamine amide showed excellent cytotoxicity (for example, EC50 = 0.6 μM for HT29 colon adenocarcinoma cells).
Keywords: 1,4-cyclohexyldiamines; betulinic acid; cytotoxicity; oleanolic acid; platanic acid; ursolic acid.