The antinociceptive and anti-inflammatory activities of Piptadenia stipulacea Benth. (Fabaceae)

In this study, we attempted to identify the possible antinociceptive and anti-inflammatory actions of the aqueous phase, the ethyl acetate phase and one unknown flavonoid obtained from aerial parts of Piptadenia stipulacea, known in Brazil as "jurema-branca", "carcará" and "rasga-beiço".

Aerial parts of Piptadenia stipulacea were used and after fractionation, the flavonoid FGAL was obtained. Experiments were conducted on Swiss mice using the acetic acid-induced writhing test, the hot plate test, the formalin-induced pain test and zymosan A-induced peritonitis test.

The aqueous and ethyl acetate phases (p.o., 100mg/kg); and the flavonoid FGAL (p.o. and i.p. at 100 micromol/kg), reduced the nociception produced by acetic acid, by 49.92%, 54.62%, 38.97% and 64.79%, respectively. In vivo inhibition of nociception by the ethyl acetate phase (100mg/kg, p.o.) in the hot plate test was favorable, indicating that this fraction exhibited central activity. The ethyl acetate phase (100mg/kg, p.o.) reduced the formalin effects in both phases by 28.51% and 55.72%, respectively. Treatment with the aqueous phase (100mg/kg, p.o.) and FGAL (100 micromol/kg, i.p.) only protected the second phase by 69.76% and 68.78%, respectively. In addition, it was observed in the zymosan A-induced peritonitis test that the aqueous phase, the ethyl acetate phase and the FGAL exhibited anti-inflammatory activity, reducing significantly the number of recruit cells by 35.84%, 37.70% and FGAL (1), respectively.

These data demonstrate that the FGAL elicits pronounced antinociceptive activity against several pain models. The actions of this flavonoid probably are due to antioxidative properties. However, pharmacological and chemical studies are continuing in order to characterize the mechanism(s) responsible for this antinociceptive action and also to identify other active substances present in Piptadenia stipulacea.