Inhibition of α-Glucosidase and α-Amylase by Vaccinium floribundum and Aristotelia chilensis Proanthocyanidins

Extracts from Vaccinum floribundum and Aristotelia chilensis, two promising South American berry species, were characterized in terms of their phytochemical composition and ability to inhibit alpha-glucosidase and alpha-amylase activities in vitro. A. chilensis contained 45.7 mg/g DW total anthocyanins (cyanidin-3-glucososide (C3G) equivalents). Seven anthocyanins were identified in this berry, of which delphinidin-3-glucoside was the main anthocyanin. A. chilensis contained proanthocyanidin dimers (56%) and trimers (14%). V floribundum was comprised of trimers (68%) and in less proportion pentamers (16%) and hexamers (8%). V floribundum proanthocyanidins inhibited both alpha-glucosidase (IC50=35 mu g/mL) and alpha-amylase (IC50=25 mu g/mL), which warrants further research into potential dietary use of this berry in therapies to combat diabetes symptoms.