The antioxidative phytochemicals in various fruits and vegetables are widely recognized for their role in scavenging free radicals, which are involved in the etiology of many chronic diseases. Colored fruits are especially considered a quality trait that correlates with their nutritional values and health benefits. The specific aim of this study was to investigate the antioxidants in the juice and freeze-dried flesh and peel of red pummelo and their ability to scavenge free radicals and compare them with those in white pummelo juice. The total phenolic content of red pummelo juice extracted by methanol (8.3 mg/mL) was found to be significantly higher than that of white pummelo juice (5.6 mg/mL). The carotenoid content of red pummelo juice was also significantly higher than that in white pummelo juice. The contents of vitamin C and delta-tocopherol in red pummelo juice were 472 and 0.35 mug/mL, respectively. The ability of the antioxidants found in red pummelo juice to scavenge radicals were found by methanol extraction to approximate that of BHA and vitamin C with a rapid rate in a kinetic model. The ability of methanol extracts of freeze-dried peel and flesh from red pummelo to scavenge these radicals was 20-40% that of BHA and vitamin C effects. Fresh red pummelo juice is an excellent source of antioxidant compounds and exhibited great efficiency in scavenging different forms of free radicals including DPPH, superoxide anion, and hydrogen peroxide radicals.

The effects of maternal vitamin E supplementation on the antioxidant status of chicks were investigated. Female breeder chicks were fed corn-soybean growing diets without supplemental vitamin E for a 17-wk developmental period. After 17 wk, the birds were randomly assigned to 5 treatments and fed corn-soybean diets supplemented with 0, 40, 80, 120, and 160 mg/kg vitamin E (all-rac-alpha-tocopherol acetate), respectively. Blood samples were collected and pullets were artificially inseminated at 35 wk of age. Eggs laid beginning on d 2 after insemination were placed in an incubator. At the time of hatching, 12 chicks from each treatment were randomly sampled and killed. Livers and brains of chicks were collected for the subsequent evaluation of antioxidant status. Plasma vitamin E concentrations increased linearly (P < 0.001; r = 0.997) with the increase in supplemental vitamin E, but those in egg yolk reached a plateau at 120 mg/kg supplemental vitamin E. The malondialdehyde (MDA) concentration, an indicator of lipid peroxidation, of chick brain decreased linearly (P < 0.01; r = -0.909) with the increase in supplemental vitamin E. Pullets given 160 mg/kg supplemental vitamin E had lower plasma MDA concentrations than those given 0 mg/kg (P < 0.05). Similar results were found for the reactive oxygen species levels, an indicator of oxidative stress, of chick brain and liver. For antioxidant enzymes, chicks of pullets given 120 mg/kg supplemental vitamin E had higher (P < 0.05) activities of liver catalase than those given 0-80 mg/kg. Chicks of pullets given 160 mg/kg supplemental vitamin E had higher (P < 0.05) activities of brain superoxide dismutase than those given 0-40 mg/kg. These results indicated that maternal supplementation with high levels of vitamin E (120-160 mg/kg) enhances antioxidant capability and depresses oxidative stress in chicks.

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