The major objective of the study was to evaluate the gastroprotective property of andrographolide, a chief component of the leaves of Andrographis paniculata in terms of the ulcer preventive effect in rats. An acute toxicity test was conducted with different concentrations of andrographolide to determine the LD50 value. The dose responsive study was conducted in rats pretreated with andrographolide (1, 3 and 5 mg/kg) for a period of 30 days, prior to ulcer induction by administering ethanol, aspirin or by pyloric ligation. The ulcer protective efficacy was tested by determining the ulcer score, pH, pepsin, titrable acidity, gastric mucin, lipid peroxides, reduced glutathione, and enzymatic antioxidants superoxide dismutase, catalase and glutathione peroxidase in gastric tissue. The activities of H+-K+ ATPase and myeloperoxidase were also determined in gastric tissue. The LD50 value was found to be 48 mg/kg b. wt and the effective dose was found to be 3 mg/kg. We have observed a significant reduction in the ulcer score in rats pretreated with 3 mg of andrographolide/kg body weight. A favourable increase in the pH and decrease in titrable acidity were observed in the gastric fluid of rats pretreated with the test drug. The gastric tissue H+-K+ ATPase and myeloperoxidase activities were elevated in ulcer-induced animals. The elevation in the enzyme activity was significantly minimized in the andrographolide received animals. The antioxidants and mucin levels were significantly maintained in the gastric tissue of drug-pretreated animals. Andrographolide did not produce any toxic effects in normal rats. This study reveals that the ulcer preventive efficacy of andrographolide may probably due to its antioxidant, cytoprotective and antiacid secretory effects.

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