engleski

Inhibition of α-glucosidase by polyphenols present in traditional apples varieties

This work aimed to evaluate polyphenols from two traditional apple varieties as a-glucosidase inhibitors. Polyphenols were extracted from the flesh and skin of two traditional apple varieties ('Božićnica' and 'Batulenka') by using ultrasonic- assisted extraction. Total polyphenols in extracts were determined by the spectrophotometric Folin- Ciocalteu method, expressed as gallic acid equivalents (GAE). The α- glucosidase activity was evaluated based on the spectrophotometric determination of p- nitrophenol (pNP) released from p-nitrophenylα-D- glucopyranoside (p-NPG) substrate by the action of the enzyme. To inhibit enzyme activity, various polyphenol concentrations were added to the reaction mixture. IC50 value was calculated (concentration of polyphenols that gives 50 % inhibition). 'Božićnica' and 'Batulenka' contained 337.24 and 202.17 mg GAE/kg in the flesh and 2132.91 and 824.43 mg GAE/kg in the peel, respectively. Polyphenols inhibited a- glucosidase activity and inhibition reached a steady state. IC50 values, expressed as µg of gallic acid equivalents (GAE) per mL of reaction solution, of the flesh of 'Batulenka' and 'Božićnica' were 1.69 and 1.47, respectively. Peel showed similar IC50 values (1.07, and 0.33 μg GAE/mL, for the peel of 'Batulenka' and 'Božićnica', respectively). These results suggest that polyphenols from the flesh and skin of traditional apple varieties are potent inhibitors of α-glucosidase activity

α-glucosidase ; inhibition ; polyphenols ; apple

nije evidentirano