In vitro and in vivo activities of tea catechins against Helicobacter pylori

Abstract

The catechin epigallocatechin gallate showed the strongest activity of the six tea catechins tested against Helicobacter pylori (MIC for 50% of the strains tested, 8 microg/ml). It had bactericidal activity at pH 7 but not at pH </=5.0. In infected Mongolian gerbils, H. pylori was eradicated in 10 to 36% of the catechin-treated animals, with significant decreases in mucosal hemorrhage and erosion. Tea catechins, therefore, may have therapeutic effects on H. pylori infection.

FIG. 1

Chemical structures of tea catechins.

FIG. 2

Effect of EGCg on H. pylori viability in liquid medium. H. pylori YMA78 was cultured microaerobically in Mueller-Hinton broth supplemented with 10% heat-inactivated horse serum at 37°C with reciprocation in the presence of EGCg at concentrations of 128 (▵), 64 (●), 32 (▴), 8 (■), and 0 (○) μg/ml. Culture samples (100 μl) were taken at the times indicated, and viability was measured by the plate colony count technique.

FIG. 3

Effect of EGCg on H. pylori viability in buffers at various pHs. H. pylori YMA78 was incubated microaerobically in each buffer at 37°C with reciprocation in the presence of EGCg at concentrations of 500 (▴), 250 (●), and 0 (○) μg/ml. Viability was determined at each time point indicated.