HPLC-Determination of Phenolic Composition and Antioxidant Capacity of Cactus Prickly Pears Seeds

The aim of this investigation is to compare the total polyphenols, total tanins, total flavonoids and antioxidant activities determined by three assays (total antioxidant capacity, DPPH, reducing power) of cactus prickly seeds at two stages of ripening (in ripe fruit and over ripe fruit). It was found that their contents were highest in seeds of ripe fruit. The effects of two extracting methods (maceration and hydrolysis) on phenolic composition of cactus seeds were evaluated by RP-HPLC. In cactus seeds of ripe fruit, the major compound detectd in methanolic macerate was catechin (61.00%) followed by rutin, (10.10 %). In contrast, the hydrolysis extract contained quercetin (37.00 %) as the most abundant component followed by dihydroxycinnamic acid (27.60 %) and epigallocatechin (10.90 %). For cactus seed of over ripe fruit, the mains compounds in macerate were gallic acid (44.70 %) and catechin, but in hydrolysis extract were dihydroxybenzoic acid (52.50 %), dihydroxyphenolic acid (17.30 %), epicatechin (11.30 %) and epigallocatechin (8.00 %).