Inhibitory actions of luteolin on the growth and arylamine N-acetyltransferase activity in strains of Helicobacter pylori from ulcer patients

Helicobacter pylori is now recognized as an important cause of type B gastr itis. which is strongly associated with gastric and duodenal ulcer disease. H. pylori may be a causative factor. in patients with gastric cancer. The growth inhibition and N-acetylation of 2-Aminofluorene (AF) or P-aminobenzo ic acid (PABA) by arylamine N-acetyltransferase (NAT) in H. pylori were inh ibited by luteolin. a component in herbal medicine. The growth inhibition w as based on the changes of optical density (OD) by using a spectrophotomete r. The N-acetylation of AF or PABA by NAT from H. pylori were assayed by th e amounts of acetylated rind nonacetylated AF or PABA in cytsols and intact bacteria of H. pylori by using HPLC. An inhibition of growth on H. pylori demonstrated that luteolin elicited a dose-dependent growth inhibition in t he H. pylori cultures. Cytosols and suspensions of H. pylori with or withou t specific concentrations of luteolin co-treatment showed different percent ages of AF or PABA acetylation. The data indicated that there was decreased NAT activity associated with increased levels of luteolin in H. pylori cyt osols and suspensions. Using standard steady-state kinetic analysis, it was demonstrated that luteolin was a possible uncompetitive inhibitor to NAT e nzyme in H. pylori. This report is the first demonstration to show that lut eolin can inhibit H. pylori growth and NAT activity. (C) 2001 Elsevier Scie nce Ltd. All rights reserved.