Effect of methanol extract of Bombax malabaricum leaves on nitric oxide production during inflammation.

In different parts of India, Bombax malabaricum DC. (Family: Bombacaceae), a lofty deciduous tree with large leaves, is traditionally used in inflammation. The aim of the present study was to confirm its anti- inflammatory activity and to search for the possible mechanism of action for methanol extract of Bombax mal- abaricum leaves (MEBM). The anti-inflammatory activity of MEBM was evaluated in a carrageenan-induced model of acute inflammation. As inflammation usually involves increased nitric oxide (NO) production, effect of MEBM on lipopolysaccharide-induced NO production in mouse peritoneal macrophages was studied to eval- uate its possible mechanism of action. It was found that MEBM was non-toxic up to a dose of 2 g/kg for mice and rats, orally. MEBM (100, 200, and 400 mg/kg) significantly reduced carrageenan-induced rat paw edema (p < 0.05, p < 0.01, p < 0.001, respectively). In mice peritoneal macrophages, the IC50 for MEBM was 258.33 ± 6.96 µg/mL and it was non-toxic up to 125 µg/mL. MEBM (0-100 µg/mL) reduced lipopolysaccharide- induced NO production in macrophages in a dose-dependent fashion (p < 0.001). Hence, MEBM possesses anti- inflammatory activity, mediated through inhibition of NO production.