Abstract
Insulina (Cissus sicyoides L.) has been used as a folk medicine for diabetes and hypertension in Brazil. To clarify the physiological function of Insulina that suppresses the elevation of portal glucose levels, various treatment methods were examined using α-glucosidase inhibitory activity as an in vitro index. Insulina leaf extract showed inhibition of α-glucosidase activity after extraction with hot water, and the inhibition was strengthened by additional roasting treatment before heat extraction. Furthermore, the duration and intensity of the α-glucosidase inhibitory activity of Insulina extracts administered to unrestrained, unanesthetized rats with portal vein cannulae were examined. Under continuous intragastric sucrose infusion, Insulina extracts suppressed the elevation of portal glucose levels and extended the duration of the inhibitory effects achieved by roasting and heating treatment. These results suggest that Insulina extract might be useful for prevention of diabetes, at least through the α-glucosidase inhibitory activity that is increased by roasting and heating.
