Anti-rheumatic activity of Ananas comosus fruit peel extract in a complete Freund's adjuvant rat model

Context: Rheumatoid arthritis is a chronic, autoimmune and systemic inflammatory disease, which targets synovial joints leading to joint destruction mediated in part by migration of inflammatory cells into the synovial tissue.Objective: The present study evaluates the anti-rheumatic effect of a methanol extract of Ananas comosus (L.) Merr. (Bromeliaceae) peel in rats.Materials and methods: Anti-rheumatic activity of crude extract of peels of A. comosus in complete Freund's induced arthritis model in rats was studied at doses of 50, 100, 250 and 500mg/kg b.w. for 21 days. Parameters such as paw size, levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), C-reactive proteins (CRP) and prostaglandins (PGE(2)) were analysed.Results: Oral administration of the extract significantly reduced the swelling in the paw of rats (EC50 65.12.95mg/kg b.w.) with a maximal inhibition of 77.01 +/- 10.53% on 21st day at 500mg/kg b.w. The extract also significantly reduced the levels of SOD, CAT and GPx in liver (EC50 26.84 +/- 16.37, 68.37 +/- 19.22, 106.54 +/- 34.81mg/kg b.w., respectively), kidney (EC50 261.75 +/- 81.5, 176.38 +/- 8.08, 14.32 +/- 6.64, mg/kg b.w., respectively) and spleen (EC50 152.14 +/- 39.57, 83.97 +/- 14.6, 47.1 +/- 10.45mg/kg b.w., respectively); and CRP (EC50 36.37 +/- 12.4mg/kg b.w.) and PGE(2) (EC50 191.06 +/- 71.54mg/kg b.w.) in tissue homogenate and serum, respectively, at 500mg/kg b.w. as compared to arthritic control group.Discussion and conclusion: These results suggest that A. comosus fruit peel extract exerts anti-rheumatic activity.