Investigating the Anti-Inflammatory and Analgesic Activity of Leaves of Wedelia chinensis (Osbeck) Merr. In Standard Experimental Animal models

The ethanolic extract of Wedelia chinensis (EEWC) belonging to the family of Asteraceae was evaluated by hot plate and acetic acid induced writhing methods to assess its analgesic activity. The extract was also evaluated for its by using on carrageenan, mediators such as histamine and serotonin induced paw oedema, and cotton pellet induced granuloma tests for its effect on acute and chronic phase inflammation models in rats, as well as analgesic activity in mice. It was found that the extract caused an inhibition on the writhing response induced by acetic acid in a dose dependent manner. Dose of 500 mg/kg EEWC and aspirin could block the writhing response by 51.92 % and 68.68 % (p < 0.001), respectively. It was also indicated that the EEWC showed significant antinociceptive action in hot plate reaction time method in mice. This effect was comparable to that of standard drug morphine treated controls, suggesting the central activity of EEWC. Maximum inhibition (56.14 %) was obtained at the dose of 500 mg/kg after 3 h of drug treatment in carrageenan induced paw oedema, whereas indomethacin (standard drug) produced 61.65 % of inhibition. In the chronic model (cotton pellet induced granuloma) the EEWC (125,250 and 500 mg/kg) and standard drug showed decreased formation of granuloma tissue by 56.69,34.57,43.30 % and 55.23 % respectively. The results indicate the potent analgesic and anti-inflammatory effects and therapeutic efficacy of Wedelia chinensis extract on animal models which are comparable with those of standard drugs such as Aspirin, Morphine and Indomethacin respectively.