和厚朴酚对幽门螺杆菌生长和空泡毒素A表达及活性的影响

【目的】幽门螺杆菌(Helicobacter pylori, H. pylori)是胃炎和消化性溃疡的病原体, 但其具有潜在的正常菌群的特性。本研究通过评价临床常用中药厚朴的活性成分和厚朴酚对H. pylori的抑制作用及对其空泡毒素A表达和活性的影响, 以反映其对H. pylori具有的潜在去除毒性的作用。【方法】使用平皿稀释固体法和脑心浸液液体法测定和厚朴酚对H. pylori的最低抑菌浓度, 进一步通过中性红摄入法评价经无抑菌效果的低浓度和厚朴酚干预后, H. pylori培养上清中空泡毒素A (Vacuolating cytotoxin A, VacA)的毒性作用; 并通过RT-PCR和Western blot方法检测经低浓度和厚朴酚处理后, H. pylori菌体及分泌上清中VacA mRNA和蛋白的表达水平。【结果】发现高浓度(0.75 g/L)和厚朴酚对H. pylori 具有抑制作用; 而在远低于最低抑菌浓度时, 和厚朴酚可有效抑制H. pylori VacA的形成和分泌。【结论】和厚朴酚具有下调H. pylori毒性的潜在作用, 这为基于“致病性H. pylori的非致病性转变”这一机理的干预性治疗提供了有希望的研究前景。

Effect of honokiol on Helicobacter pylori growth and the expression and activity of vacuolating cytotoxin A

[Objective] Helicobacter pylori (H. pylori) was not only the pathogen of gastritis and peptic ulcer, but a potential normal flora. We detected the effect of honokiol (HK), a kind of Chinese herbal active ingredient from Mangnolia officinalis commonly used in clinical treatment, on H. pylori growth and the expression and activity of VacA to demonstrate the potential effect of HK on down-regulating the toxicity of H. pylori. [Methods] We detected the minimum inhibitory concentration (MIC) of HK and further identified the toxic effect of VacA secreted from H. pylori by neutral red uptake test, and the mRNA and protein levels of VacA in H. pylori and its supernatants by RT-PCR and Western blot, after treated with a low concentration HK (0.09 g/L) without bacteriostatic effects. [Results] The results showed that the high concentration HK (0.75 g/L) can inhibit the growth of H. pylori, and HK could also inhibit the expression and activity of VacA effectively in the concentration far below the MIC. [Conclusion] HK could down-regulate the toxic effect of H. pylori potentially, and which provided a hopeful research prospect for intervention treatment based on transforming the pathogenic H. pylori to the non-pathogenic.