Radical scavenging activity of orange and tangerine varieties cultivated in Brazil

Four citrus fruit varieties cultivated in Brazil (two kinds of sweet orange and two kinds of tangerine) were analyzed for physicochemical characteristics contents of total phenolics, total carotenoids and ascorbic acid, and antioxidant activities. The antioxidant activities of aqueous, methanolic, and acetone extracts of the citrus fruit juices were assessed on the basis of their ability to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH•). The cravo tangerine has the highest content of citric acid, while the pera orange is richest in ascorbic acid. The lima orange has the highest total phenolic contents, and the ponkan the highest total carotenoids. The antioxidant activities, expressed as the concentration of antioxidant able to scavenge 50% of the initial DPPH• (EC₅₀), ranged from 139.1 ± 27.3 to 182.2 ± 28.8 g extract/l for juice of orange varieties and 186.3 ± 29.6 to 275.5 ± 3.3g extract/l for juice of tangerine citrus varieties. In methanolic extracts the EC₅₀ ranged from 192.5 ± 43.1 to 267.4 ± 41.4 g extract/l for orange varieties and from 225.2 ± 69.8 to 336.3 ± 27.2 g extract/l for tangerine varieties. For EC₅₀ values of acetone fractions, there were no statistically significant differences between the different varieties. For every citrus fruit in the present study, the radical scavenging capacity was higher in the aqueous than in the methanolic or acetone fractions.