INHIBITION OF GASTRIC H+,K+-ATPASE AND ACID-SECRETION BY ELLAGIC ACID

The effects of ellagic acid on gastric H+,K+-ATPase, acid secretion, and the occurrence of gastric ulcers were studied. Ellagic acid inhibited hog gastric H+,K+-ATPase activity with a 50% inhibition at 2.1 x 10(-6)M; kinetic studies showed that the inhibition of H+,K+-ATPase by ellagic acid is competitive with respect to ATP and is noncompetitive with respect to K+. The effect on gastric ulcers was investigated by using a stress ulcer model. Intraperitoneal administration of ellagic acid at above 5 mg/kg markedly reduced the occurrence of gastric lesion. Ellagic acid significantly reduced acid secretion at the same doses. These results suggest that ellagic acid has a marked inhibitory effect on acid secretion and the occurrence of stress-induced gastric lesions, and these effects may be attributed to the inhibition of H+,K+-ATPase activity.