Synthesis and cytotoxic activity of the N-acetylglucosamine-bearing triterpenoid saponins.

Fourteen ursolic acid and oleanolic acid saponins with N-acetyl-beta-D-glucosamine, and (1-->4)-linked and (1-->6)-linked N-acetyl-beta-D-glucosamine oligosaccharide residues were synthesized in a convergent manner. The structures of all compounds were confirmed by (1)H NMR and (13)C NMR spectroscopy and by mass spectrometry, and their cytotoxic activities were assayed in three cancer cell lines. Only oleanolic acid-3-yl beta-D-GluNAc showed significant cytotoxicity against HL-60 and BGC-823.