Casca do araticum (Annona crassiflora Mart.) como fonte de compostos antioxidantes com atividade de inibição de α-amilase, α-glicosidase e glicação não enzimática

Abstract

The Cerrado fruits are a source of antioxidant compounds and the characterization of their biomolecules has attracted the interest of the scientific community because of their safety and potential nutritional and therapeutic effects. A bioguided assay was performed to identify the main bioactive compounds of Annona crassiflora Mart. fruit peel from the ethanol extract fractions with antioxidant capacity and α-amylase, α-glucosidase and glycation inhibitory activities. Antioxidant capacity was determined using DPPH (scavenging of 2,2-diphenyl-1-picrylhydrazyl free-radical), ORAC (scavenging capacity of peroxyl radical) and FRAP (iron-reducing capacity) methods. The α-amylase inhibition was evaluated by a colorimetric kinetic assay using an enriched fraction of salivary α-amylase (HSAf) and 2-chloro-p-nitrophenol linked to maltotriose. The α-glucosidase inhibition was determined by a colorimetric kinetic assay using an enriched fraction of α-glucosidase from rat intestinal acetone powder (HIGf) and 4-nitrophenyl-α-D-glucopyranoside. Anti-glycation activity was determined by a fluorometric method using bovine serum albumin incubated with fructose. The bioactive compounds of the fruit peel were identified by liquid chromatography coupled to mass spectrometer (HPLC-ESI-MS/MS). All assays were performed in triplicate, with various concentrations of the organic partitions from ethanolic extract of A. crassiflora fruit peel. Ethyl acetate and n-butanol partitions showed higher antioxidant capacity, promising inhibitory activities against α-amylase, α-glucosidase and glycation and lower cytotoxicity, compared to the other partitions and crude ethanol extract. The HPLC-ESI-MS/MS analysis revealed the presence of biomolecules known as potent antioxidants, such as chlorogenic acid, (epi)catechin, procyanidins, caffeoyl-hexoside, quercetin-glucoside and kaempferol. The fruit peel of Annona crassiflora, a specie of the Brazilian biodiversity, showed a source of antioxidant compounds with properties to block carbohydrate digestive enzymes and formation of glycation products. Thus, there is a potential in using by-products of A. crassiflora in order to identify and isolate phytochemicals for applications in nutraceutical supplements, food additives and pharmaceuticals products, and thereby contribute economically and socially through recovery of agro-industrial residues.