姜黄提取物的抑菌活性及对细菌胞膜作用的研究

Antibacterial activity of turmeric(Curcuma longa L)extract and effect on bacterial cell membranes

本研究通过测定最小抑菌浓度(minimum inhibitory concentration, MIC)分析姜黄提取物的抑菌谱,并通过检测姜黄提取物对抑制效果最佳的受试菌(枯草芽孢杆菌)细胞膜的通透性及完整性、能量代谢及菌体形态的影响,阐述姜黄提取物的膜作用抑菌机制。结果表明,姜黄提取物具有广谱抑菌活性,对革兰阳性菌、革兰阴性菌及真菌均有一定抑制作用,对枯草芽孢杆菌的抑制活性最强, MIC为0.5 mg·mL^(-1)。姜黄提取物可扰乱脂质体膜释放钙黄绿素,能增加细菌胞膜通透性引起胞内K^(+)、Ca^(2+)和细胞壁间蛋白的泄漏,以及破坏细胞膜的完整性,使胞内蛋白、多糖外漏。扫描电镜观察证实经姜黄提取物处理的细菌形态严重变形,在此过程中还影响细胞能量代谢,使细菌胞内ATP含量和ATP酶活力显著降低。因此姜黄提取物具有的抑菌活性与其破坏细菌膜结构的作用密切相关。

In the present study,the antibacterial spectrum of turmeric extract was analyzed by measuring the minimum inhibitory concentration(MIC),and the antibacterial mechanism of turmeric extract was elaborated by determining its effects on the permeability and integrity of the cytoplasmic membrane,energy metabolism,and the morphology of the tested bacteria(Bacillus subtilis)with the highest susceptibility to the extract.The results showed that turmeric extract possessed broad-spectrum antibacterial activity against Gram-positive,Gram-negative bacteria and fungi,especially against Bacillus subtilis,with the MIC of 0.5 mg·mL^(-1).Turmeric extract disrupted the liposome membrane and released calcein encapsulated within it.The permeability of the bacterial cell membrane was increased,leading to leakage of intracellular K^(+),Ca^(2+)and cell wall proteins,and the integrity of the cell membrane was broken down,causing leakage of intracellular proteins and polysaccharides.Scanning electron microscope observation confirmed that the bacteria treated with turmeric extract was severely deformed.Simultaneously,cellular energy metabolism was affected,resulting in a significant reduction in the intracellular ATP content and ATPase activity in bacteria.In summary,the antibacterial mode of turmeric extract is closely related to its disruption of bacterial membrane structure.