α-Glucosidase inhibitory activity of cyanidin-3-galactoside and synergistic effect with acarbose

Cyanidin-3-galactoside, a natural anthocyanin, was investigated for its alpha-glucosidase inhibitory activity. The IC(50) value of cyanidin-3-galactoside was 0.50 +/- 0.05 mM against intestinal sucrase. A low dose of cyanidin-3-galactoside showed a synergistic inhibition on intestinal alpha-glucosidase (maltase and sucrase) when combined with acarbose. A kinetic analysis showed that cyanidin-3-galactoside gave a mixed type inhibition against intestinal sucrase. The results indicated that cyanidin-3-galactoside was an alpha-glucosidase inhibitor and could be used in combination with acarbose for treatment of diabetes.