Stimulatory effects of Antidesma madagascariense on D-glucose, L-tyrosine, fluid and electrolyte transport across rat everted intestine, comparable to insulin action in vitro

Abstract

Medicinal plants are believed to be an important source of potential therapeutic agents. This study investigates the effects of Antidesma madagascariense (AM) extract on the transport of D-glucose, L-tyrosine, fluid and electrolytes (Na+ and K+) across rat everted intestinal sacs. These sacs were mounted in an organ bath containing Krebs-Henseleit bicarbonate (KHB) buffer. Experimental findings showed that incubation with graded aqueous AM extracts above 0.375 mg/mL significantly (P<0.05) stimulated the mucosal disappearance and serosal appearance of glucose and fluid. The concentration of glucose accumulated in the intestinal tissues also increased significantly (P<0.05) compared to that found in the controls. Transport of the amino acid L-tyrosine was not significantly enhanced (P>0.05) when incubated with increasing concentrations of AM extract. Effects on electrolyte (K+ and Na+) transport were assessed. Na+ uptake and transport was significantly enhanced (P<0.05) when incubated with 0.75 mg/mL AM extract; however, K+ transport was not significantly enhanced (P>0.05). For comparison, insulin (1 and 2 units/mL) was incubated in the mucosal solution. Aqueous AM extract produced similar stimulatory effects on the transport of glucose, fluid and Na+ as were found with insulin. It is hypothesised that bioactive phytochemicals such as flavonoids, alkaloids, leucoanthocyanins, phenols and saponins from AM leaf extract might interfere with the Na+/glucose carrier, thereby enhancing the transport of glucose, Na+ and fluid across rat everted intestinal sacs. Thus, AM may represent a possible alternative dietary supplement for the treatment of type 2 diabetes.