In vitro anti-Helicobacter pylori activity of irisolidone isolated from the flowers and rhizomes of Pueraria thunbergiana

The inhibitory effect of isoflavones isolated from the flowers and rhizomes of Pueraria thunbergiana (Leguminosae) on the growth of Helicobacter pylori (HP) was investigated, Isoflavone glycosides did not inhibit the growth of HP. However, their aglycones, irisolidone, tectorigenin and genistein, inhibited HP growth. Among them, irisolidone had the most potent inhibitory activity against HP and its MIC was 12.5-25 mug/ml. Genistein only weakly inhibited the urease of HP and H+/K+-AT-Pase of rat stomach: its IC50 were 0.43 and 0.89 mg/ml, respectively.