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).
五环三萜齐墩果酸、熊果酸、白桦酸和悬铃木酸被乙酰化并转化为几种酰胺9-31;它们的细胞毒性已在使用苯丙红B的实验中确定,涉及多个人类肿瘤细胞系和非恶性成纤维细胞。因此,一种白桦酸/反式-1,4-环己二胺酰胺显示出优异的细胞毒性(例如,HT29结肠腺癌细胞的EC50 = 0.6μM)。