EXPLORING THE MECHANISMS OF GASTROPROTECTIVE ACTION OF ALSTONIA SCHOLARIS IN RATS

Background and Aim: Alstonia scholaris (A. scholaris) is used traditionally in folk medicines for inflammation, wound, dyspepsia, gastritis and ulcer. Previously, it has been reported to possess gastro-protective activity in ethanol-induced ulcer model. However, it has not been established that how does A. scholaris protect the stomach from exogenous inflammatory agents. Keeping in view above statement, the study was aimed to investigate various pathways possibly involved in protecting the gastric mucosa from agent like ethanol. Materials and Methods: Five different pathways; α-2 adrenergic receptor, ATP-dependent K+ channel, Histamine, Prostaglandin and Nitric oxide were examined through their specific inhibitors to explore their involvement in gastro-protective action of aqueous extract of A. scholaris leaves. In every pathway, animals were pretreated with their specific agonist or antagonist for 30 mins following administration of aqueous extract of A. scholaris leaves for an hour. After that ethanol was administered for an hour and then animals were sacrificed. Biochemical and physiological parameters such as volume of gastric acid, its pH, calculation of ulcer index by examining the score of ulcer, calculation of total acidity, protein contents and mucous adherence to gastric wall were determined. The data were analyzed by using one way ANNOVA followed by Dunnett’s test. Key Results: A. scholaris caused a significant (p < 0.001) gastro-protective effect in ethanol induced ulcer model. Glibenclamide (5mg/kg, p.o.), inhibitor of KATP-channel and Histamine (3mg/kg, s.c.), an agonist of histamine pathway suppressed the gastro-protective action of A. scholaris. However, its gastro-protective activity was observed in α-2 adrenergic receptor, Prostaglandin and Nitric oxide pathway in the presence of their respective antagonists. Conclusions and Implications: The data suggests that gastro-protective activity of aqueous extract of A. scholaris leaves may involve blockade of histamine receptors most likely H-2 receptor. In addition, it also showed its ability to stimulate KATP channels in ATP-dependent K+ channel mediated pathway. Therefore, it is concluded that A. scholaris has shown a tendency to modify proton pump in a way to be protective of gastric mucosa