Anti-Helicobacter pylori activities of 9-substituted palmatine derivatives

Fifteen 9-substituted palmatine (1) derivatives were synthesized and evaluated for their anti-Helicobacter pylori (Hp) activities in vitro. Structure-activity relationship studies revealed that introducing appropriate substituted secondary amino group at position 9 of lead 1 might be beneficial for potency. Among them, compound 5a showed the most potential activity against metronidazole (Met) resistant Hp isolates with minimal inhibitory concentrations (MICs) of 4 μg·mL^-1, much better than that of lead 1. Compound 5a displayed satisfactory safety profile in acute toxicity assay. Molecular docking suggested that 5a might act on Hp urease. The results provided key scientific evidence for the development of 1 derivatives into a new class of anti-Hp component.