Betulinic acid methyl ester is a lupane-type triterpenoid and an esterified version of betulinic acid that has been found in Helicteres hirsuta and has diverse biological activities. It inhibits HIV-1 reverse transcriptase (IC50 = 11 μM). Betulinic acid methyl ester is active against L. braziliensis and T. cruzi (IC50s = 69.9 and 93.3 μM, respectively). It induces melanogenesis in (EC50 = 2.5 μM) and inhibits the growth of B16 2F2 melanoma cells in vitro (IC50 = 4.9 μM). Betulinic acid methyl ester is cytotoxic to SK-LU-1, HepG2, HeLa, SK-MEL-2, and AGS cells (IC50s = 60.84, 77.43, 80.17, 66.17, and 69.94 μg/ml, respectively).
