Pigment composition and antioxidant capacity of betacyanins and betaxanthins fractions of Opuntia dillenii (Ker Gawl) Haw cactus fruit

A purification and fractionation of Opuntia dillenii (Ker-Gawl) Haw extracts followed by betalainic and phenolic characterization by HPLC-DAD-ESI-MS were carried out. Several betalains and polyphenols have been identified, the majority of them not previously described in Opuntia dillenii: 17-decarboxybetanin and 17-decarboxyisobetanin, 6'-O-sinapoyl-O-gomphrenin and 6'-O-sinapoyl-O-isogomphrenin, 2'-O-apiosyl-4-O-phyllocactin and 5 '' O-E-sinapoyl-2'-apiosyl-phyllocactin as betacyanins, tryptophan-betaxanthin and tyrosine-betaxanthin (portulacaxanthin II) as betaxanthins and isoramnethin-3-glucuronide and quercetin-3-O-glucoside as polyphenolic compounds. Moreover, the antioxidant activity of extracts of Opuntia dillenii (Ker-Gawl) Haw fruit followed the ensuing decreasing order (crude extract (CE) > purified extract (PE) > red fraction (RF) > yellow fraction (YF)), is in concordance with the Folin-Ciocalteau reduction capacity (FCRC). These evidence suggest that Opuntia dilenii is a rich source of bioactive compounds, with a high amount of total betacyanins (16.63 mg betanin/100 g fresh fruit) and betaxanthins (7.55 mg indicaxanthin/100 g fresh fruit).