厚朴酚及和厚朴酚对变异链球菌形态及细胞膜通透性的影响

Effects of Magnolol and Honokiol on the morphology and cellular membrane permeability of Streptococcus mutans

目的:研究厚朴酚及和厚朴酚对变异链球菌形态、细胞膜通透性的影响。方法:以变异链球菌(S.mutans)ATCC 25175为实验菌株,测定厚朴酚及和厚朴酚的最低抑菌浓度(MIC)及最低杀菌浓度(MBC)。以MIC、10×MIC的厚朴酚及和厚朴酚为实验组,青霉素G为阳性对照组,生理盐水为阴性对照组,然后加入液体培养基培养实验菌株。用扫描电镜观察细菌表面形态,原子吸收分光光度计测定培养基中的钙离子浓度。结果:厚朴酚及和厚朴酚MIC(μg/m L)分别为15.7、7.8,MBC(μg/m L)分别为125、62.5;作用于S.mutans后,细菌结构及形态与阴性对照组相似,表面光滑、饱满;阳性对照组细菌表面呈"桑椹状",可见部分菌体破裂。实验组细菌的培养液中钙离子浓度高于阴性对照组(P<0.05),低于阳性对照组(P<0.05)。同种药物作用下,10×MIC浓度组较MIC浓度组培养液中钙离子浓度增加(P<0.05);相同药物浓度下,和厚朴酚组培养液中钙离子浓度高于厚朴酚组(P<0.05)。结论:厚朴酚及和厚朴酚对S.mutans形态无明显影响,但可导致细胞内钙离子的流失,具有浓度依赖性,且和厚朴酚的作用强于厚朴酚。

AIM：To investigate the effects of magnolol and honokiol on the morphology and cellular mem-brane permeability of Streptococcus mutans （ S. mutans ） . METHODS：The minimum inhibitory concentration （ MIC ） and the minimum bactericidal concentration （MBC） of magnolol and honokiol on S. mutans ATCC 25175 were meas-ured. S. mutans were treated by magnolol and honokiol at of MIC and 10 x MIC respectively. Penicillin G was used as the positive control and saline as the negative control. Morphology of the bacteria were observed by a scanning electron microscope. The concentration of calcium ions in culture medium was measured by an atomic absorption spectrophotom-eter. RESULTS：After treatment with magnolol and honokiol, the morphology and structure of S. mutans showed no obvious changes. The bacteria arranged in a chain with a smooth surface. While in positive control group, S. mutans showed damaged structure with a “ mulberry - like’’ surface. Calcium concentration of the experimental groups was higher than that of the negative control group（P 〈0.05）,but lower than positive control（P 〈0.05）. With both treat-ment, calcium concentrations in 10 x MIC groups were higher than that of MIC groups （P 〈 0. 05 ） . In the same con-centration groups, calcium concentrations in honokiol groups were higher than that of magnolol groups （ P 〈 0. 05 ）. CONULUSION：Magnolol and honokiol do not induce obvious morphological changes of S. mutans. Both magnolol and honokiol may increase the cellular membrane permeability of S. mutans.