Effect of Extracts of Bilberries (Vaccinium myrtillus L.) on Amyloglucosidase and α-Glucosidase Activity
Background: Vaccinium myrtillus L. is a species belonging to the genus Vaccinium of the family Ericaceae. Bilberries have drawn attention due to the multiple benefi ts for the human health, including antioxidant, anti-infl ammatory, anticancer, anti-neurodegenerative, and cardioprotective eff ects. Recently, bilberries were shown to inhibit the activity of carbohydrate-hydrolysing enzymes that can help reduce the intensity of the metabolic syndrome and prevent type 2 diabetes.
Aim: In this study, we investigated the α-glucosidase and amyloglucosidase inhibitory activities of polyphenol-rich extracts from fruit of Vaccinium myrtillus L. from diff erent regions in Bulgaria.
Materials and methods: The total phenolic content was determined spectrophotometrically using the Folin-Ciocalteu method. With HPLC analysis, phenolic acid composition of extracts was assessed. Enzymatic inhibitory activities were determined according to the methodology by Borooah et al. (1961), and Dewi et al. (2007). Amyloglucosidase assay and α-glucosidase assay were used to measure the inhibition potential of bilberries’ extracts.
Results: Phenolic compound content ranged from 1299.60 mg to 510.88 mg GAE/100 g for organic extracts and from 453.63 mg to 290.83 mg GAE/100 g for aqueous extracts. Based on qualitative HPLC analyses, gallic acid and chlorogenic acid were found to be among the major phenolic acids present in bilberries. Methanol and aqueous extracts there were found to be eff ective inhibitors of α-glucosidase with an IC50 value of 20 μg GAE/ml and 55 μg GAE/ml, respectively.
Conclusion: The inhibitory activity of bilberries’ extracts towards α-glucosidase off ers the patients with type 2 diabetes the opportunity to manage their own glycaemic levels with a diet.