Gastric H+, K(+)-ATPase inhibition by catechins.
Five catechins, (+)-catechin, (-)-epicatechin, (-)-epicatechin gallate, (-)-epigallocatechin and (-)-epigallocatechin gallate, inhibited gastric H+, K(+)-ATPase activity with IC50 values ranging from 1.7 x 10(-4) to 6.9 x 10(-8) M, with (-)-epigallocatechin gallate as the most potent inhibitor. The intensity of inhibitor activity paralleled the number of phenolic hydroxy groups in the molecule. The inhibition of the enzyme by (-)-epicatechin was competitive with respect to ATP and noncompetitive with respect to K+. These findings suggest that the anti-secretory and anti-ulcerogenic effects of catechins previously reported, are due to their inhibitory activity on gastric H+, K(+)-ATPase.
Murakami
S
S
Research Center, Taisho Pharmaceutical Co. Ltd, Ohmiya, Japan.
Muramatsu
M
M
Otomo
S
S
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002392:Catechin / Q000032:analysis / Q000494:pharmacology*; D066298:In Vitro Techniques; D054328:Proton Pump Inhibitors; D013270:Stomach / Q000201:enzymology*; D013552:Swine
D054328:Proton Pump Inhibitors; D000255:Adenosine Triphosphate; D002392:Catechin