Hypoglycemic properties of banana pseudo-stems

Abstract

Water extract of banana (Musa sapientum L.) pseudo-stems has been claimed by Lebanese herbalists to be efficient in the treatment of diabetes mellitus. This work aimed at verifying the alleged effect and at elucidating its possible mode of action. Administration of the extract in replacement of drinking water to streptozotocin-induced diabetic rats, did reduce significantly blood glucose levels. The mechanism of action of the extract was studied by investigating its involvement in intestinal glucose absorption and its effect on the Na+/K+ ATPase and glucose transporters SGLT1 and GLUT2 in the rat jejunum. Rat jejuna were perfused in situ with Krebs Ringer buffer containing [14C] 3-O-methyl-D-glucose, and the activity of the Na+/K+ ATPase in jejunal homogenates was assayed in vitro, by measuring the amount of inorganic phosphate released in presence and absence of inhibitors of the ATPase. The extract induced a significant reduction in glucose absorption and Na+/K+ ATPase activity, but did not affect the protein expression of SGLT1 and GLUT2 glucose transporters. It was concluded that the extract acts by reducing the Na+/K+ ATPase activity and consequently the sodium gradient required for sugar transport by SGLT1. Reduced activity of SGLT1 leads to a decrease in intracellular glucose and in the number of apical GLUT2 [1], which contributes to the observed hypoglycemic effect. The current on going work focuses on identifying the active ingredient(s) in the extract.