IN-VITRO AND IN-VIVO ANTIBACTERIAL ACTIVITY OF PLAUNOTOL, A CYTOPROTECTIVE ANTIULCER AGENT, AGAINST HELICOBACTER-PYLORI

Recently, some antiulcer agents have been reported to have antibacteri al activity against Helicobacter pylori, which is highly associated wi th gastritis and peptic ulcers. In-vitro and in-vivo activity of plaun otol, a cytoprotective antiulcer agent, against H. pylori was investig ated. Antibacterial activity of plaunotol against a standard strain (N CTC 11637) and 14 clinical isolates was compared with those of other c ytoprotective antiulcer agents: benexate, sofalcone, teprenone, cetrax ate, and gefarnate, by an agar dilution method. The MIC(50) and MIC(90 ) of plaunotol against 15 strains were 6.25 and 12.5 mg/L, respectivel y, making it the most potent of the cytoprotective antiulcer agents. T he bactericidal effect of plaunotol was investigated using an in-vitro killing assay. Plaunotol at concentrations of more than 6 mg/L induce d a rapid reduction of culture turbidity, with an extensive loss of vi ability, within 30 min. Observation by scanning electron microscopy re vealed that plaunotol caused autolysis and treated cells were deformed . In-vivo activity of plaunotol against H. pylori was examined in a nu de mouse gastritis model. Plaunotol significantly decreased the number of H. pylori in the stomach of nude mice. In addition, the antiulcer agent enhanced the antibacterial activity of amoxycillin or clarithrom ycin in the infection model.