Comparative study of antioxidant and inhibitory activity on α-glucosidase and glycogen phosphorylase A of berry extracts from Ugni molinae genotypes

BACKGROUND: Sustained hyperglycemia leads to multiple health complications associated with oxidative balance and metabolic pathways alterations. Current treatments for hyperglycemia are not entirely effective thus, the identification of natural products from food sources, such as Ugni molinae berries, to reduce hyperglycemia and prevent the deleterious effect of oxidative stress is attractive to develop new therapeutics. OBJECTIVE: Our aim was to evaluate the antioxidant capacity and the inhibitory activity on α-glucosidase and glycogen phosphorylase A of polyphenolic extracts from different genotypes of U. molinae berries and to comparatively analyze their polyphenolic profile. METHODS: Berry extraction was performed by exhaustive maceration with increasing-polarity solvents. The antioxidant capacity, and inhibitory activity on enzymes were analyzed by different spectrophotometric methods. Moreover, the chemical profile of bioactive extracts was comparatively evaluated through LC-MS. RESULTS: 16 semi-purified extracts were obtained and showed antioxidant capacity and inhibitory activity on the evaluated enzymes. Moreover, the chemical analysis showed differences in phenolic profile among the extracts and, particularly, the acetonic extracts were more concentrated in phenolic compounds, which is associated with the more potent activities. CONCLUSIONS: Our results indicate that murtilla berries’ acetonic extracts include a mixture of phenolic compounds that inhibit the activity of two enzymes related to carbohydrate metabolism and have a promising antioxidant capacity.