Comparative antibacterial effect of gallic acid and catechin against Helicobacter pylori

•The effect of gallic acid and catechin on H. pylori cultures was investigated.•Both polyphenols displayed growth inhibitory effects on H. pylori.•The antibacterial effects were dependent on dose, contact time and polyphenol.•Gallic acid showed a higher inhibitory effect compared to catechin.•A partially additive effect between catechin and gallic acid was observed.

The antimicrobial effect of gallic acid and catechin on Helicobacter pylori cultures was investigated. The antimicrobial effect was evaluated by measuring the absorbance of liquid culture media at 600 nm, by an agar-well diffusion method and by scoring colony forming units. Both polyphenols displayed strong growth inhibitory effects on two strains of H. pylori (26695 and ATCC 43504). The antibacterial effects were dependent on dose, contact time and type of polyphenol. Gallic acid showed a higher inhibitory effect on both H. pylori strains compared to catechin. Partially additive growth inhibitory effect between catechin and gallic acid was observed.