Anti-Arthritic Effects of Palisota hirsuta K. Schum. Leaf Extract in Freund's Adjuvant-Induced Arthritis in Rats

The anti-arthritic effect of an ethanolic leaf extract of Palisota hirsuta, a plant used locally in Ghana for various painful inflammatory conditions was assessed, using the Freund's adjuvant induced-arthritis model in rats. Palisota hirsuta Extract (PHE) as well as dexamethasone and methotrexate, used as positive controls, showed significant dose-dependent anti-arthritic properties prophylactically, curatively and also in combination therapy. PHE (30-300 mg kg(-1)) significantly reduced the arthritic edema in the ipsilateral paw with the highest dose used giving a maximum inhibition of 13.02+/-8.77%. PHE 300 mg kg(-1) also significantly prevented the spread of the edema from the ipsilateral to the contralateral paw indicating inhibition of systemic spread. Dexamethasone (0.3-3 mg kg(-1)) and methotrexate (0.1-1.0 mg kg(-1)) significantly and in a dose dependent manner also inhibited polyarthritis edema as well as completely preventing the spread of the arthritis from the ipsilateral to the contralateral paws of the treated animals. PHE in combination with methotrexate did not show any significant effect, however, there was a significant inhibition of arthritis in both the acute and the polyarthritis phases when PHE was combined with dexamethasone. Dexamethasone in combination with methotrexate gave the greatest inhibition of both phases with an extreme level of significance as expected. Overall, the present results demonstrate that PHE has anti-arthritic effect which could be similar to that exhibited by methotrexate.