Effect of Cleome arabica leaf extract on rat paw edema and human neutrophil migration

The anti-inflammatory activity of Cleome arabica leaf extract was studied in vivo and in vitro. Firstly, the extract was examined for its anti-inflammatory activity using carrageenan-induced rat paw edema as a model of acute inflammation. A subplantar injection of 0.1 ml of carrageenan 1% induced a progressive swelling of the rat paw in all time points, that reached a maximal volume in placebo group within 5 h. Results showed that pre-treatment of rats by Cleome arabica leaf extract, 1 h prior the injection of the phlogogenic agent, prevented the increase of the edema in dose-dependent manner with an ED50 of 231 mg/kg, body weight. The extract doses 100, 200 and 300 mg/kg, reduced edema to 65.54 +/- 5.2%, 57.86 +/- 8%, and 41.54 +/- 3.6%, respectively, 5 h after the carrageenan injection. Secondly, we have examined the effect of Cleome arabica leaf extract on human neutrophil migration induced by fMLP (10(-7) M), using 48-well chemotaxis chamber. Results showed that the extract inhibited neutrophil chemotaxis significantly (p < 0.01) and in a dose-dependent manner. Neutrophil migration was reduced to 16.71 +/- 4.6% in presence of 50 mu g/ml of Cleome arabica leaf extract. It appears that the antiinflammatory activity of Cleome arabica leaf extract, observed in vivo as well as in vitro, could be due to its high flavonoid content (19%). These results may contribute to explain the use of this plant in folk medicine.