Triterpenes involved in the anti-inflammatory effect of ethanolic extract of Pterodon emarginatus Vogel stem bark

Bioassay-guided fractionation of the ethanolic extract of Pterodon emarginatus Vogel stem bark (EtEx) resulted in the isolation and characterization of lupeol and betulin. Their structures were elucidated by spectroscopic methods including IR, H-1-NMR, C-13-NMR and comparison with literature values. This study showed the anti-inflammatory activity of EtEx, the hexane (HexL) and dichloromethane (DichL) layers, and lupeol and betulin. The extract, HexL, DichL, lupeol and betulin were able to inhibit acetic acid-induced writhing. In the formalin test, EtEx decreased licking time only in the second phase characterizing anti-inflammatory activity. In the oil-induced ear oedema test, EtEx, lupeol and betulin decrease edema formation. In conclusion, EtEx has antinociceptive effects arising from anti-inflammatory activity; this activity could be due to the presence of lupeol and betulin.