Role of nutraceutical starch and proanthocyanidins of pigmented rice in regulating hyperglycemia: Enzyme inhibition, enhanced glucose uptake and hepatic glucose homeostasis using in vitro model.

Dysregulation of glucose homeostasis result in hyperglycemia and pigmented rice, unique combination of high quality starch and phenolics has the potential in regulating it. In this study, pigmented rice was characterized in terms of nutraceutical starch (NS) and phenolic content. Further the effect of rice phenolics on carbolytic enzyme inhibition, glucose uptake, hepatic glucose homeostasis and anti-glycation ability was analyzed in vitro. The most relevant effect on enzyme inhibition (α-amylase: IC50-42.34 µg/mL; α-glucosidase: IC50:63.89 µg/mL), basal uptake of glucose (>39.5%) and anti-glycation ability (92%) was found in red rice (RR), than black rice (BR). The role of RR phenolics in regulating glucose homeostasis was deciphered using hepatic cell line system, which found up-regulation of glucose transporter 2 (GLUT2) and glycogen synthase 2 (GYS2); while expression of gluconeogenic genes were found down regulated. To our knowledge this study is the first report validating the role of starch-phenolic quality towards anti-hyperglycemic effect of RR.