Abstract: OBJECTIVE: To evaluate in vitro and in vivo antiarthritic potential of Solanum nigrum(S.nigrum).METHODS: Aqueous methanolic(70:30) extract of S.nigrum was prepared.The in vitro antiarthritic effect was evaluated in terms of its inhibition of protein denaturation and membrane stabilization.While, formaldehyde, complete Freund's adjuvant(CFA) and Collagen induced arthritis rat models were used to study in vivo antiarthritic activities of S.nigrum at dose level of 200, 400 and 800 mg/kg.RESULTS: The extract exhibited inhibition of protein denaturation and protected red blood cell by stabilizing the membranes in a concentration dependent manner, with maximum effect attained at 800 μg/mL.Moreover, there was a marked reduction in paw edema observed in extract treated animals, when compared to arthritic control animals in all in vivo models and 800 mg/kg dose got maximum reduction of paw edema.In CFA and collagen models, plant extract restored body weight, hematologic parameters, radiographic and histopathologic alterations towards normal.CONCLUSION: It could be concluded that S.nigrum holds antiarthritic potential, supporting its traditional use in treatment of rheumatoid arthritis.

Key words: Arthritis, Solanum nigrum, Protein denaturation, Formaldehyde, Freund's adjuvant, Collagen