ANTIINFLAMMATORY ACTION OF PLUCHEA-SAGITTALIS - INVOLVEMENT OF AN ANTIOXIDANT MECHANISM

Pluchea sagittalis (Lam.) Cabr., a popular medicinal herb grown in Sou th America, was studied for anti-inflammatory and antioxidant activiti es. The anti-edema action of P. sagittalis aqueous extract was assayed in different models of inflammation: 1) the mouse ear edema test indu ced by arachidonic acid and croton oil; 2) the rat hind-paw edema test produced by several inflammatory inductors: carrageenan, dextran, zym osan, platelet-activating factor (PAF) and arachidonic acid; 3) a suba cute model based on the rat carrageenan air-pouch granuloma test. Bloo d leukocyte free radical production was measured by flow cytometry wit h 2',7'-dichlorofluorescin diacetate (DCFH-DA) in vivo, in rats with i nduced air-pouch granuloma, and in a model in vitro, stimulating leuko cytes with hydrogen peroxide. The aqueous extract of P. sagittalis sho wed a marked anti-inflammatory effect in both ear edema tests, dextran and carrageenan hind-paw edemas and carrageenan air-pouch model. It a lso had a potent antioxidant activity in blood leukocytes, both in viv o and in vitro. Our results correlate the reduction of free radical pr oduction with the anti-inflammatory effect of this plant.