Identification of phenolic antioxidants and bioactives of pomegranate seeds following juice extraction using HPLC-DAD-ESI-MSn

Phenolics from free and hydrolyzed fractions of pomegranate juice (PJ) and seeds (PS) were evaluated. In general, total phenolic contents and scavenging of ABTS(center dot+), DPPH and hydroxyl radicals, as well as metal chelation of the soluble fraction from PS, were higher than those for PJ. Insoluble-bound phenolics from PS accounted for up to 27% of total scavenging capacity (free + esterified + insoluble-bound). Phenolic acids (13), monomeric flavonoids (8), hydrolysable tannins (12), proanthocyanidin (1) and anthocyanins (12) were tentatively characterized using HPLC-DAD-ESI-MSn. Several compounds were identified for the first time in PJ or PS. The inhibition of DNA damage (induced by hydroxyl and peroxyl radicals), copper-induced LDL-cholesterol peroxidation, as well as alpha-glucosidase and lipase activities were demonstrated, therefore supporting the potential exploitation of PJ and PS as sources of bioactive compounds. (C) 2016 Elsevier Ltd. All rights reserved.