Pentagalloylglucose, an antisecretory component of Paeoniae radix, inhibits gastric H+, K+-ATPase

We purified a compound with strong inhibitory effect on H+, K+-ATPase from Paeoniae radix, which has been used in Japan for the treatment of gastritis and peptic ulcers. The compound was identified as 1,2,3,4,6,-penta-o-gallo yl-beta-o-glucose by proton nuclear magnetic resonance, carbon-13 nuclear m agnetic resonance, and fast atomic bombardment mass spectrometry. The IC50 of the compound for H+, K+-ATPase was 166 nmol/l. Kinetic analyses indicate d that the inhibition of the enzyme by pentagalloylglucose was noncompetiti ve with respect to K+. Pentagalloylglucose had relatively weak inhibitory e ffects for Mg+-ATPase (IC50: >10 mu mol/l) and Na+, K+-ATPase (IC50: 2.7 mu mol/l). Pentagalloylglucose also inhibited the accumulation of [C-14]amino pyrine in parietal cells that had been isolated from guinea pig stomach and stimulated by 10 mu mol/l histamine (IC50: 7.8 mu mol/l) and 1 mmol/l dbc- AMP (IC50: 10 mu mol/l). These results suggest that pentagalloylglucose is a potent inhibitor of H+, K+-ATPase and may be responsible for inhibition o f acid secretion by Paeoniae radix. (C) 2000 Elsevier Science B.V. All righ ts reserved.