Potential for antioxidant and antihyperglycemic activities of four everbearing strawberry cultivars

'Goha', 'Gangha', 'Gwanha', and 'Yeolha' are newly-developed Korean everbearing strawberry (Fragaria ananassa Duch.) cultivars. Bioactive phytochemicals play a crucial role in the prevention of cancer, cardiovascular, neurodegenerative, and metabolic diseases. We examined the free radical scavenging activity and alpha-glucosidase inhibitory activity in these four cultivars and a junebearing cultivar 'Seolhyang' for comparison. 'Gwanha' showed the strongest 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2 '-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radical scavenging activities, and 'Gwanha' and 'Goha' had the most potent alpha-glucosidase inhibitory activity. Total anthocyanin content (TAC) was the highest in 'Gwanha'. The major anthocyanin components of everbearing strawberry were determined to be pelargonidin-3-O-glucoside (Pg3G), pelargonidin-3-O-rutinoside, and cyanidin-3-O-glucoside (C3G). A correlation study between activity and components revealed that TAC was highly correlated with antioxidant and antihyperglycemic activities, and in principal component analysis, C3G is highly correlated with antioxidant activity and Pg3G is highly correlated with the antihyperglycemic effect of everbearing strawberries. Among the four everbearing strawberry cultivars, 'Gwanha' and 'Goha' are rich sources of pelargonidin showing strong alpha-glucosidase inhibitory activity and are promising dietary sources to prevent diabetes.