Α‐amylase and Tyrosinase Inhibitory Activities, Phenolic Contents, and Antioxidant Capacities of Wild and Cultivated Blueberries

The phenolic compound contents, antioxidant capacities, and alpha-amylase and tyrosinase inhibitory activities of 10 wild and 19 cultivated blueberries grown in northeast China were evaluated. The results showed that the alpha-amylase inhibitory activities of the blueberries represented, by 1/IC50, correlated with their total phenolic contents (TPCs). Moreover, the tyrosinase inhibitory activities correlated with the total anthocyanin contents (TACs). High-performance liquid chromatography and electrospray mass spectrometry were conducted to determine and identify seven phenolic acids. The average caffeic acid contents of the cultivated and wild blueberries were 277.37 and 17.71 mu g/g, respectively. The total phenolic, anthocyanin, and flavonoid contents were determined. Wild blueberries have higher TPCs, alpha-amylase inhibitory activities, and antioxidant capacities. Cultivated blueberries have higher TACs and exhibit tyrosinase inhibitory activities similar to those of the wild ones. Practical applications This study revealed that wild blueberries have high alpha-amylase inhibitory activities and are effective as natural alpha-amylase inhibitors for the treatment of diabetes. In addition, wild blueberries were found to be rich in phenolics and have high antioxidant capacities. Thus, because of these properties, wild blueberry products with antidiabetic and antioxidant potential can be developed for use in biomedical and pharmaceutical industries.