Identification of bioactive compounds from jambolao (Syzygium cumini) and antioxidant capacity evaluation in different pH conditions

The composition of carotenoids and phenolic compounds from jambolao fruits (Syzygium cumini was determined by HPLC-DAD-MS/MS. Two main carotenoids were found in the fruits, all-trans-lutein (43.7%) and all-trans-beta-carotene (25.4%). The anthocyanin composition was characterised by the presence of 3,5-diglucosides of five out of six aglycones commonly found in foods. This pattern was also observed for the other flavonoids, since diglucosides of dihydromyricetin, methyl-dihydromyricetin and dimethyl-dihydromyricetin, along with myricetin glucoside and a galloyl-glucose ester were identified. Furthermore, the antioxidant capacity of a functional extract rich in anthocyanins was evaluated through the scavenging capacities of ABTS. and peroxyl radical (ORAC) and the protective effect against singlet oxygen (O-1(2)). The TEAC values indicated that the hemiacetals/chalcones and quinonoidal bases species (pH >= 5) possess higher scavenging capacity as compared to the flavylium cation (pH < 3). The functional extract also showed 60% of dimethylanthracene protection against O-1(2) and an ORAC value of 16.4 mu mol Trolox/g fruit. (C) 2010 Elsevier Ltd. All rights reserved.