臭茉莉正丁醇提取物抑菌活性研究

Studies on Antibacterial Activity of N-butanol Extracted from Clerodendrum philippinum var.simplex

目的:研究臭茉莉正丁醇提取物(ECP)的抑菌效果及机理。方法:采用纸片扩散法、微量肉汤稀释法测定表皮葡萄球菌、金黄色葡萄球、伤寒杆菌及绿脓杆菌对ECP的敏感性。并通过考察金黄色葡萄球菌(S.aureus)细胞膜、细胞壁及形态结构等的变化,研究ECP的抑菌活性及机理。结果:ECP对4种供试细菌均具有抑菌活性,其中对S.aureus的抑菌活性最强,其最低抑菌浓度(MIC)及最低杀菌浓度(MBC)均为0.5 mg/mL。ECP处理后S.aureus细胞内容物外泄、氧化损伤和细胞凋亡均明显增加,脱氢酶活性及蛋白含量均明显下降,扫描电镜(SEM)观察到菌体形态结构受损严重。结论:ECP对S.aureus的抑菌靶点可能为细胞膜、细胞壁、三羧酸(TCA)循环关键酶、蛋白质和遗传物质等,臭茉莉具有成为天然食品添加剂的潜力。

Objective:The antibacterial effect and mechanism of N-butanol extracted from Clerodendrum philippinum var. simplex(ECP)was studied. Methods:The sensitivity of Staphylococcus epidermidis,Staphylococcus aureus,typhoid bacillus and Pseudomonas aeruginosa to ECP were determined by disk diffusion method and broth dilution method. And the antibacterial effects and mechanisms of ECP on S.aureus were studied in the aspects of cell wall,cell membrane and morphological structure. Results:ECP had antimicrobial activity on all of the four test bacteria. Among which,it was the most powerful for S. aureus,and the minimum inhibitory concentration(MIC)and the minimum bactericidal concentration(MBC)were both 0.50 mg/mL. After S.aureus was treated with ECP,the leakage of content from intracellular,cellular oxidative damage and apoptotic were all increased obviously. At the same time,the activities of dehydrogenases and protein content were both decreased significantly. Scanning electron microscope(SEM)results indicated that the whole cell was damaged severely. Conclusions:The targets of ECP inhibition on the growth of S.aureus might be the cell membrane,cell wall,key enzymes of tricarboxylic acid(TCA)cycle,proteins and genetic material and so on. And Clerodendrum philippinum had specific potential for natural food additives.