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

Abstract

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-galloyl-β-D-glucose by proton nuclear magnetic resonance, carbon-13 nuclear magnetic resonance, and fast atomic bombardment mass spectrometry. The IC50 of the compound for H+, K+-ATPase was 166 nmol/l. Kinetic analyses indicated that the inhibition of the enzyme by pentagalloylglucose was noncompetitive with respect to K+. Pentagalloylglucose had relatively weak inhibitory effects for Mg+-ATPase (IC50: >10 μmol/l) and Na+, K+- ATPase (IC50: 2.7 μmol/l). Pentagalloylglucose also inhibited the accumulation of [14C]aminopyrine in parietal cells that had been isolated from guinea pig stomach and stimulated by 10 μmol/l histamine (IC50: 7.8 μmol/l) and 1 mmol/l dbc-AMP (IC50: 10 μmol/l). These results suggest that pentagalloylglucose is a potent inhibitor of H+, K+-ATPase and may be responsible for inhibition of acid secretion by Paeoniae radix.