Anti-inflammatory and antioxidant activity of Ageratum conyzoides

Ageratum conyzoides L., a plant widely used in African and South American folk medicine, contains many active principles, including pyrrolizidine alkaloids and polymethoxyflavones. We undertook the present study to evaluate the effect of the methanol extract and of the flavonoid fraction of the aerial part of the plant on carrageenan-induced edema in rat. We subjected the methanol extract to column chromatography to separate the flavonoids and assayed the radical scavenging activity of this fraction by the DPPH method. The two preparations produced significant inhibition on carrageenan-induced rat paw edema, until 2 h after carrageenan treatment. The flavonoids exhibited a strong inhibitory activity on the DPPH radical. The anti-inflammatory effect of A. conyzoides methanol extract depends on the flavonoid fraction, which could produce a protective action against free-radical mediated damage in cells and tissue. Therefore, it is possible to hypothesize that flavonoids influence inflammatory gene protein expression.