Characterization of araçá fruits (Psidium cattleianum Sabine): Phenolic composition, antioxidant activity and inhibition of α-amylase and α-glucosidase

Abstract

Araçá fruits (Psidium cattleianum Sabine) have been reported to have several biological activities, including the inhibition of the digestives enzymes. Nevertheless, the compounds responsible for these activities are not known. This study evaluated the potential of araçá phenolic fractions to inhibit the activity of α-glucosidase and α-amylase and related it to their phenolic composition. Extracts of edible portions (pulp-peel and seeds) of fruits from three araçá genotypes were purified and fractionated. Total phenolic content was determined using a spectrophotometric method, and individual phenolic compounds were quantified using HPLC-MS. Their enzyme inhibition and antioxidant potential were measured using in vitro assays. Higher amounts of total phenolic content were observed in pulp-peel than in seeds. These results were partially associated with the slightly higher enzyme inhibition of pulp-peel fractions. In general, araçá phenolic fractions were more active towards α-glucosidase than α-amylase when compared to acarbose, the current drug used to inhibit α-glucosidases. The antioxidant potential was dependent on accession, part of the fruit and fraction. Moreover, compounds present in the crude and purified extracts, and fractions III (quercetin, ellagic acid and p-coumaric acid) and IV (cyanidin-3-O-glucoside and malvidin-3-O-glucoside) for some samples resulted in significant inhibition of the two enzymes.