Effect of ORT on intestinal disaccharidase activity. Lactase (A), sucrase (B), and maltase (C) activity were measured at the proximal region of the small intestine. Values are presented as the mean ± SE. Means with different letters are significantly different at p < 0.05 using Duncan’s multiple range test. NS not significant, NC normal control, DC diabetes control, DORT diabetes + oxyresveratrol, DMet diabetes + metformin