Anti-nociceptive and anti-inflammatory activities of Wrightia arborea.

Anti-nociceptive and anti-inflammatory effects of methanolic extract of Wrightia arborea (MEWA) were examined using different models in rats. MEWA was given to rats orally upto 2000 mg kg(-1) b.wt. for acute toxicity study and observed for 14 days. Anti-nociceptive activity was evaluated in rats against Acetic acid induced writhing (chemically induced pain) and Tail immersion method (thermally induced pain). Acute anti-inflammatory activity of MEWA was also evaluated in Formaline-induced rat paw edema model and Carrageenan-induced hind paw edema model in rats. Results demonstrated that no mortality was found upto single dose of 2000 mg kg(-1) b.wt. in rats even after 14 days observation. In comparison to control group MEWA at 100 and 200 mg kg(-1) b.wt. showed highly significant anti-nociceptive activity against chemically (p < 0.001) as well as thermally (p < 0.05 and p < 0.001) induced pain as compared to standard drugs, indomethacin and nalbufin, respectively. In the formalin test, both the doses of 100 and 200 mg kg(-1) of extract significantly prevented increase in volume of paw edema (p < 0.05 and p < 0.01) both in the neurogenic and inflammatory phases. MEWA (200 and 400 mg kg(-1) p.o.) also significantly prevented increase in volume of paw edema in Carrageenan test (p < 0.05 and p < 0.001). The results suggest that MEWA has significant analgesic and anti-inflammatory potential which may be mediated by central and peripheral mechanism.