Comparison and screening of bioactive phenolic compounds in different blueberry cultivars: Evaluation of anti-oxidation and α-glucosidase inhibition effect

This study was aimed to investigate antioxidation and alpha-glucosidase inhibition of the bioactive compounds in three cultivars of blueberry ('Northland' (NL) from the hybrid blueberry (V. corymbosum L. x V. angustifolium Aiton), 'Britewell' (BW), and 'Gardenblue' (GB) from the rabbiteye blueberry (Vaccinium ashei Reade)). A total of eighteen anthocyanins were identified and quantified in Anthocyanins (ACNs), among which four acylated anthocyanins were exclusively found in Northland. The blueberry anthocyanin extracts (BAEs) were further measured the antioxidant activity and alpha-glucosidase inhibition effect. Northland BAEs exhibited significantly superior antioxidant activity compared with BAEs of other cultivars, and the antioxidant activity was correlated with the content of anthocyanins. However, alpha-glucosidase inhibition test showed that Britewell BAEs had the strongest inhibitory effect. BAEs were further separated into anthocyanin fraction (AF) and copigment fraction (CF). Fifteen phenolic acids and four iridoids were identified in CF. In terms of alpha-glucosidase inhibition effects, the CF from three cultivars could inhibit alpha-glucosidase in a dose-dependent manner, while the AF did not show significant inhibitory effects. The blueberry exhibits excellent antioxidant activity and alpha-glucosidase inhibition.