Cranberry extract suppresses interleukin-8 secretion from stomach cells stimulated by Helicobacter pylori in every clinically separated strain but inhibits growth in part of the strains

It is known that cranberry inhibits the growth of Helicobacter pylori (HP). In human stomach, HP basically induces chronic inflammation by stimulating stomach cells to secrete interleukin (IL)-8 and other inflammatory cytokines, and causes stomach cancer, etc. The aim of this study was to investigate the inhibiting effects of cranberry on HP growth and IL-8 secretion from stomach cells induced by HP, using clinically separated HP strains. HP growth in liquid culture and on-plate culture was evaluated by titration after 2-day incubation and by agar dilution technique, respectively. For IL-8 experiments, MKN-45, a stomach cancer cell line, was incubated with HP for 24 h and IL-8 in the medium was assayed by ELISA. Cranberry suppressed growth of the bacteria only in six of the 27 strains. Meanwhile, it suppressed IL-8 secretion in all the strains. The results may suggest a possible role of cranberry in prevention of stomach cancer by reducing gastric inflammation.