Extraction of flavonoids from Honey pomelo leaves and study on its antioxidant and uric acid reduction activities

In order to investigate the extraction processes of flavonoids from Honey pomelo leaves and its antioxidant and uric acid reduction activities, the extraction conditions of flavonoids were optimized primarily by orthogonal array design.In addition, the DPPH·, hydroxyl free radical and superoxide anion free radical scavenging activities were determined to evaluate the antioxidant activity of the flavonoids and the inhibition of xanthine oxidase activity was determined to preliminary judging its uric acid reduction activity.Results indicated that optimal extraction processing parameters were the ratio of material to solvent of 1: 30 ( g/mL) , ethanol concentration of 80%, extraction temperature of 80 ℃, extraction time of 6 h, the extraction efficiency of flavonoids from Honey pomelo leaves was 12.41 mg/g. Meanwhile, in DPPH radical, hydroxyl radical and superoxide anion scavenging assays, the IC₅₀ of the scavenging activities of flavonoids from Honey pomelo leaves were 1.47, 1.04 mg/mL and1.49 mg/mL. The inhibition of xanthine oxidase assay illustrated that the flavonoids showed a certain degree of suppression effect of xanthine oxidase ( IC₅₀: 4.8 mg/mL) .