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 α-glucosidase and α-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 α-glucosidase (IC50=35 μg/mL) and α-amylase (IC50=25 μg/mL), which warrants further research into potential dietary use of this berry in therapies to combat diabetes symptoms.