Plaunotol suppresses interleukin-8 secretion induced by Helicobacter pylori: therapeutic effect of plaunotol on H. pylori infection.

ABSTRACT

BACKGROUND: It has been suggested that gastric mucosal injury induced by Helicobacter pylori infection is mediated by interleukin-8 (IL-8). METHODS: We studied the effect of plaunotol, a drug extracted from the Plau-noi tree of Thailand, and reported it to be effective in the treatment of ulcers, of IL-8 secretion induced by H. pylori and of the inhibitory adhesion activity of the bacterium to gastric epithelial cells. Moreover, the therapeutic effect of plaunotol on H. pylori infection was assessed by using the gnotobiotic murine model. RESULTS: Plaunotol inhibited the growth of H. pylori (1.5 x 10(4) c.f.u./mL) at high doses (24-48 microg/mL), but not at low doses (3-6 microg/mL). Interleukin-8 secretion induced by H. pylori was inhibited by coculture with plaunotol in a dose-dependent manner. The adhesion of H. pylori to MKN45 cells was also suppressed by coculture with plaunotol in a dose-dependent manner. An in vivo study showed that plaunotol improved histological gastritis and decreased the H. pylori antibody titre. CONCLUSIONS: These findings suggest that plaunotol has a therapeutic effect on gastritis induced by H. pylori.