Antinociceptive effect of Phyllanthus fraternus extract in complete Freund's adjuvant induced chronic pain in mice

ObjectiveTo evaluate the effects of Phyllanthus fraternus (PF) extract on chronic inflammatory pain.MethodComplete Freund's adjuvant (CFA) induced inflammatory pain model was used to investigate the effects of (PF) extract on chronic inflammatory hypersensitivity in adult Swiss albino mice. Twenty-four hours after CFA injection, we used Von Frey filaments and acetone-evoked cooling to evaluate tactile and thermal hypersensitivity, respectively. The paw edema was measured with the help of a digital plethysmometer.ResultsSingle intraperitoneal injections of PF extract (200 & 400 mg/kg) administered 30 minutes before testing reduced CFA-induced mechanical hypersensitivity. Similarly, PF reduced acetone-evoked hypersensitivity up to 4 hours after treatment. Compared with vehicle, PF produced a marked reduction in CFA-induced paw edema. Multiple treatments with PF extracts given chronically (twice a day from 1st to 5th day and from 9th to 10th day) significantly reduced mechanical hypersensitivity induced by CFA. This multi-dose strategy did not cause tolerance.ConclusionThe present study reveals the antinociceptive activity of PF in chronic inflammatory hyperalgesia and also indicates that it might be potentially effective in management of the persistent pain.