Linolenic acid-metronidazole inhibits the growth of Helicobacter pylori through oxidation

BACKGROUND: Resistance to antibiotics is one the main factors constraining the treatment and control of Helicobacter pylori (H. pylori) infections. Therefore, there is an urgent need to develop new antimicrobial agents to replace antibiotics. Our previous study found that linolenic acid-metronidazole (Lla-Met) has a good antibacterial effect against H. pylori, both antibiotic-resistant and sensitive H. pylori. Also, H. pylori does not develop resistance to Lla-Met. Therefore, it could be used for preparing broad-spectrum antibacterial agents. However, since the antibacterial mechanism of Lla-Met is not well understood, we explored this phenomenon in the present study. AIM: To understand the antimicrobial effect of Lla-Met and how this could be applied in treating corresponding infections. METHODS: H. pylori cells were treated with the Lla-Met compound, and the effect of the compound on the cell morphology, cell membrane permeability, and oxidation of the bacteria cell was assessed. Meanwhile, the differently expressed genes in H. pylori in response to Lla-Met treatment were identified. RESULTS: Lla-Met treatment induced several changes in H. pylori cells, including roughening and swelling. In vivo experiments revealed that Lla-Met induced oxidation, DNA fragmentation, and phosphatidylserine ectropionation in H. pylori cells. Inhibiting Lla-Met with L-cysteine abrogated the above phenomena. Transcriptome analysis revealed that Lla-Met treatment up-regulated the expression of superoxide dismutase SodB and MdaB genes, both anti-oxidation-related genes. CONCLUSION: Lla-Met kills H. pylori mainly by inducing oxidative stress, DNA damage, phosphatidylserine ectropionation, and changes on cell morphology.