Antioxidant actions and phenolic and vitamin C contents of common Mauritian exotic fruits

Seventeen commonly consumed exotic fruits from Mauritius were analysed for their antioxidant capacity, total phenolics, proanthocyanidins, flavonoids and vitamin C content. Two independent methods were used to evaluate the antioxidant potential of total fruit extracts. The antioxidant activities of the fruits ranged from 1 to 47 mumol Trolox equivalent antioxidant capacity (TEAC) g(-1) fresh weight and from 0.3 to 34 micro/mol g fresh weight (FRAP) g-1 fresh weight. Total phenolics in the fruits ranged from 118 to 5638 mug g(-1) fresh weight, proanthocyanidins from 7 to 2561 mug g(-1) fresh weight, flavonoids from 21 to 712 mug g(-1) fresh weight and vitamin C content from 8 to 1426 mug g(-1) fresh weight. There were strong correlations between antioxidant activity (assessed by both TEAC and FRAP) and total phenolics and proanthocyanidins. Flavonoids seemed to contribute less to the antioxidant potential of the fruits, while very poor correlations were observed between ascorbate content and antioxidant activity. The highest antioxidant capacities were observed in red and yellow Psidium cattleianum Sabine 'Chinese guava', sweet and acid Averrhoa carambola L 'starfruit', Syzygium cumini L Skeels 'jamblon' and white Psidium guajava L 'guava'. These fruits were also characterised by high levels of total phenolics. Mauritian exotic fruits are thus a significant source of phenolic antioxidants, which may have potential beneficial effects on health. (C) 2003 Society of Chemical Industry.