Antioxidant activity of Centaurium erythraea infusion evidenced by its superoxide radical scavenging and xanthine oxidase inhibitory activity

Centaurium erythraea Rafin. (Gentianaceae) has long been used in traditiona l medicine. This plant contains considerable amounts of polyphenolic compou nds, namely, xanthones and phenolic acids as the main constituents. Because phenolic groups exhibit activity as radical scavengers and/or metal chelat ors, this study evaluated the superoxide radical scavenging properties of a lyophilized infusion obtained from C. erythraea flowering tops. Superoxide radical scavenging activity was assayed using enzymatic (xanthine/xanthine oxidase) and nonenzymatic (NADH/phenazine methosulfate) superoxide generat ing systems. This study provided evidence that C. erythraea exhibits intere sting antioxidant properties, expressed either by the capacity to scavenge superoxide radical or to noncompetitively inhibit xanthine oxidase. The mai n phenolic compounds present in this extract were several esters of hydroxy cinnamic acids, namely, p-coumaric, ferulic, and sinapic acids.