Synthesis and activity analysis of N-［3-oxo-20(29)-lupen-28-oyl］-glycine

In order to enhance the biological activity of betulonic acid, 3-oxo-20(29)-lupen-28-oic acid chloride was synthesized with betulonic acid as raw materials and oxalyl chloride as the acylating agent. Methyl ester of  N-［3-oxo-20(29)-lupen-28-oyl］-glycine was synthesized by 3-oxo-20(29)-lupen-28-oic acid chloride and methyl ester of glycine hydrochloride. N-［3-oxo-20(29)-lupen-28-oyl］-glycine was obtained by hydrolyzing methyl ester of N-［3-oxo-20(29)-lupen-28-oyl］-glycine. The structure of the product was identified by FT-IR, 1HNMR and MS spectra. Cytotoxic activity of the target product against human lung adenocarcinoma (A549), human nose carcinoma cells (CNE) and human tongue carcinoma (Tca8113) cell lines was evaluated by MTT assay via the respective IC50. The result improved the structure of N-［3-oxo-20(29)-lupen-28-oyl］-glycine. HPLC results showed that the purity of synthetic product was 97.801%. IC50 of N-［3-oxo-20(29)-lupen-28-oyl］-glycine displayed lower values than that of betulinic acid. As regards to Tca8113 cells, N-［3-oxo-20(29)-lupen-28-oyl］-glycine showed stronger activity than betulinic acid with an IC50 ratio of about 1∶11. As regards to CNE cells, N-［3-oxo-20(29)-lupen-28-oyl］-glycine showed stronger activity than betulinic acid with an IC50 ratio of about 1∶53. The bioactive assay indicates that N-［3-oxo-20(29)-lupen-28-oyl］-glycine shows stronger activity than betulinic acid in resistance to tumor development.