INHIBITORY EFFECTS OF A TRADITIONAL ANTIDIABETIC MEDICINAL FRUIT EXTRACT ON THE TRANSPORT OF INORGANIC PHOSPHATE AND D-GLUCOSE ACROSS RAT EVERTED INTESTINAL SACS- POSSIBLE RELATIONSHIP WITH A “CRABTREE-EFFECT”

Abstract

The present study was aimed at investigating the effect of an aqueous fruit extract of a traditional antidiabetic medicinal plant, Momordica charantia (MC) on the transport of D-glucose and inorganic phosphate under varying substrate concentrations across rat everted intestinal sacs model in vitro. Experimental findings showed that when D-glucose was added to the incubating buffer, inorganic phosphate uptake across rat everted intestinal sac was significantly inhibited (P < 0.05). On the other hand, when 3.0 mg/mL aqueous MC fruit extract was added to the mucosal bathing solution, uptake of D-glucose was inhibited significantly (P < 0.05) whereas inorganic phosphate transport was significantly enhanced (P < 0.05). The possible mechanism proposed is that MC extract stimulate inorganic phosphate uptake thereby inhibiting D-glucose uptake across the brush border membrane of rat everted intestinal sacs. Our study provides evidence for a Crabtree effect. These findings may provide a possible explanation for the hypoglycemic action of MC as an alternative medicine by inhibiting glucose uptake at the brush border of the small intestine. PRACTICAL APPLICATIONS Momordica charantia (MC) commonly known as bitter melon is a widely distributed and used vegetable over the world. In addition, to its nutritive value, MC has been extensively used mainly as an alternative medicine in the management of diabetes. As an abundant natural resource, MC has attracted a lot of attention among the scientific community. It has also been used as a health food with anti-oxidative property, anti-aging and immune-enhancement activities. Since the past few years, we have focused on its glucose-lowering properties at the level of the small intestines using an everted intestinal sac model. The results presented in this article contribute towards understanding the mechanism by which MC inhibits glucose absorption. These findings may provide a possible explanation for the hypoglycemic action of MC as an alternative medicine by inhibiting glucose uptake at the brush border of the small intestine. This conclusion support the rationality of MC fruit extract as a health food and may be of help in the research and development of new antidiabetic drug.