INHIBITORY-ACTION OF LANSOPRAZOLE AND ITS ANALOGS AGAINST HELICOBACTER-PYLORI - INHIBITION OF GROWTH IS NOT RELATED TO INHIBITION OF UREASE

The proton pump inhibitors omeprazole and lansoprazole and its acid-ac tivated derivative AG-2000, which are potent and specific inhibitors o f urease of Helicobacter pylori (K. Nagata, H. Satoh, T. Iwahi, T. Shi moyama, and T. Tamura, Antimicrob. Agents Chemother. 37:769-774,1993), inhibited the growth of H. pylori. The growth was inhibited not only in urease-positive clinical isolates but also in their urease-negative derivatives which had no urease polypeptides. AG-1789, a derivative o f lansoprazole with no inhibitory activity against H. pylori urease, a lso inhibited the growth of both strains even more strongly than the u rease inhibitors lansoprazole and AG-2000. Furthermore, the antibacter ial activity of omeprazole and lansoprazole was not affected by glutat hione or dithiothreitol, which completely abolished the inhibitory act ivity of lansoprazole against H. pylori urease. These results indicate d that the inhibitory action of these compounds against the growth of H. pylori was independent from the inhibitory action against urease.