The anti-inflammatory and antinociceptive properties of the chloroform fraction from Phyllanthus niruri plant is mediated via the peripheral nervous system.

Phyllanthus niruri (Euphorbiaceae) is used folklorically for the treatment of diabetes, malaria, fever, diarrhea, liver disease, and urolithiasis. As an initial step toward isolating compounds effective against inflammation and pain, this study is aimed at providing scientific evidence for the anti-inflammatory, antinociceptive, and antipyretic properties of the chloroform soluble fraction (PNF1) of Phyllanthus niruri methanol extract in rats and mice. Three doses of PNF1 [25, 50, 100 mg/kg body weight (bw)] were used. Screening was done using acetic-acid-induced writhing, egg-albumin-induced pedal inflammation, Randall-Selitto test, hot-plate test, and yeast-induced pyresis as experimental models. Results show that PNF1 significantly (p < .01) inhibited writhing response induced by acetic acid at all doses used by 56.2%-66.7% and caused significant (p < .05, p < .01) reduction of yeast-induced pyrexia (21.6%-40.9%). Significant (p < .01) reduction of egg albumin-induced inflammation was observed only at a dose of 100 mg PNF1/kg bw, which was comparable with the effect produced by aspirin (100 mg/kg bw). At 50 and 100 mg/kg bw, PNF1 significantly (p < .05, p < .01) increased pain threshold of inflamed tissue in the Randall-Selitto test but did not increase response to thermally induced pain in the hot-plate test. It is concluded that PNF1 possesses antipyretic, anti-inflammatory, and antinociceptive effects that are peripherally mediated. This justifies its use in traditional medicine and its potential as a candidate for further development.