A series of 23-hydroxybetulinic acidderivatives were prepared and tested in vitro as a new class of inhibitors of glycogenphosphorylase (GP). Within this series of compounds, 12b (IC50 = 3.5 μM) is the most potent GPa inhibitor. The preliminary SAR results of the 23-hydroxybetulinic acidderivatives are discussed.
Based on the structure of 23-hydroxybetulinic acid (1), a series of 28-amide derivatives were synthesized. Biological
evaluation in vitro for their antitumor activities against five cell lines (A549, BEL-7402, SF-763, B16 and HL-60)
has indicated that compound 6g possesses the most effective antitumor activity with an IC50 value of 10.47 μM when
treated with HL-60 cells. In vivo testing has also shown a comparable activity of 6g to cyclophosphamide against H22
liver tumor in mice and 5-fluorouracil against B16 melanoma, respectively.