茶槲寄生“螃蟹脚”醇提正丁醇萃取相对金黄色葡萄球菌抑菌机理的研究

Antimicrobial Mechanisms of the n-Butanol Phase from Tea Mistletoe Viscum articulatum Burm.F. Ethanol Extracts Against Staphylococcus aureus

摘要:

本文研究了茶槲寄生“螃蟹脚”醇提各萃取相的抑菌作用及正丁醇萃取相（NVBEs）对金黄色葡萄球菌的抑菌机理。采用滤纸片扩散法测定抑菌圈直径（DIZ）的大小，对倍稀释法测定最小抑菌浓度（MIC）和最低杀菌浓度（MBC），来评价“螃蟹脚”醇提各萃取相对金黄色葡萄球菌（S. aureus）、大肠杆菌（E. coli）、鼠伤寒沙门氏菌（S. typhimurium）、单核细胞增生李斯特菌（L. monocytogenes）4种食源性腐败菌的抑制性；通过光学显微镜和扫描电镜观察、胞膜通透性、胞壁完整性和酶活性等实验，研究了NVBEs抑菌机理。结果表明，“螃蟹脚”醇提各萃取相对S. aureus、E. coli、S. typhimurium和L. monocytogenes均有明显抑制效果，其中NVBEs抑菌活性较好，对S. aureus抑制效果最好，DIZ为9.84±0.57 mm，MIC为3.52 mg/mL，MBC为7.04 mg/mL。抑菌机理结果表明：NVBEs可增加S. aureus细胞壁及细胞膜的通透性，破坏菌体细胞结构，引起细胞内含物如核酸和蛋白质等外泄；引起遗传物质DNA的改变，使菌体细胞形态结构出现异常；影响菌体酶的代谢活动，从而抑制细菌的生长。

Abstract:

The antibacterial activity of each phase from tea mistletoe Viscum articulatum Burm.F. ethanol extracts and the antibacterial mechanism of the n-butanol phase from V. articulatum Burm.F. ethanol extracts (NVBEs) against Staphylococcus aureus were studied. The antibacterial activities of each phase from V. articulatum Burm.F. ethanol extracts against food spoilage and pathogenic bacteria, including Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, and Listeria monocytogenes, were determined by measuring the diameter of inhibition zone (DIZ) using the disc diffusion method, the minimum inhibitory concentration (MIC), and the minimum bactericidal concentration (MBC), as measured using a doubling dilution series. Furthermore, the antibacterial mechanism of NVBEs was explored using light microscopy, scanning electron microscopy, cell membrane permeability and integrity analysis, and enzyme activity assays. The results showed that each phase from V. articulatum Burm.F. ethanol extracts had significant antagonistic activity against four food-spoilage and pathogenic bacteria. Moreover, NVBEs showed relatively strong antibacterial activity, and the strongest antibacterial effect was observed for Staphylococcus aureus. The DIZ, MIC, and MBC values were 9.84 ± 0.57 mm, 3.52 mg/mL, and 7.04 mg/mL, respectively. The results showed that the NVBEs increased the permeability of the bacterial cell wall and membrane, destroyed the bacterial cell structure, and caused leakage of cellular contents, such as nucleic acids and proteins. The genetic material was altered, the cell morphology appeared to be abnormal, and the enzyme metabolic activity was affected, thus inhibiting bacterial growth.