Key Laboratory of Zoonosis, Ministry of Education, Institute of Zoonosis, College of Animal Science and Veterinary Medicine, Jilin University, Changchun, People's Republic of China.
PLoS One. 2011 Jan 19;6(1):e16160. doi: 10.1371/journal.pone.0016160.
The pathogenicity of staphylococcus aureus is dependent largely upon its ability to secrete a number of virulence factors, therefore, anti-virulence strategy to combat S. aureus-mediated infections is now gaining great interest. It is widely recognized that some plant essential oils could affect the production of staphylococcal exotoxins when used at subinhibitory concentrations. Perilla [Perilla frutescens (L.) Britton], a natural medicine found in eastern Asia, is primarily used as both a medicinal and culinary herb. Its essential oil (perilla oil) has been previously demonstrated to be active against S. aureus. However, there are no data on the influence of perilla oil on the production of S. aureus exotoxins.
METHODOLOGY/PRINCIPAL FINDINGS: A broth microdilution method was used to determine the minimum inhibitory concentrations (MICs) of perilla oil against S. aureus strains. Hemolysis, tumour necrosis factor (TNF) release, Western blot, and real-time RT-PCR assays were performed to evaluate the effects of subinhibitory concentrations of perilla oil on exotoxins production in S. aureus. The data presented here show that perilla oil dose-dependently decreased the production of α-toxin, enterotoxins A and B (the major staphylococcal enterotoxins), and toxic shock syndrome toxin 1 (TSST-1) in both methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA).
CONCLUSIONS/SIGNIFICANCE: The production of α-toxin, SEA, SEB, and TSST-1 in S. aureus was decreased by perilla oil. These data suggest that perilla oil may be useful for the treatment of S. aureus infections when used in combination with β-lactam antibiotics, which can increase exotoxins production by S. aureus at subinhibitory concentrations. Furthermore, perilla oil could be rationally applied in food systems as a novel food preservative both to inhibit the growth of S. aureus and to repress the production of exotoxins, particularly staphylococcal enterotoxins.
金黄色葡萄球菌的致病性在很大程度上取决于其分泌多种毒力因子的能力，因此，抗毒力策略来对抗金黄色葡萄球菌介导的感染现在引起了极大的兴趣。人们广泛认识到，一些植物精油在亚抑菌浓度下使用时，可以影响葡萄球菌外毒素的产生。紫苏[Perilla frutescens（L.） Britton]，一种在东亚发现的天然药物，主要用作药用和食用草药。其精油（紫苏油）以前被证明对金黄色葡萄球菌具有活性。然而，目前还没有关于紫苏油对金黄色葡萄球菌外毒素产生影响的数据。
方法/主要发现：采用肉汤微量稀释法测定紫苏油对金黄色葡萄球菌株的最低抑菌浓度（MIC）。采用溶血试验、肿瘤坏死因子（TNF）释放试验、Western blot 和实时 RT-PCR 试验评价亚抑菌浓度紫苏油对金黄色葡萄球菌外毒素产生的影响。这里呈现的数据表明，紫苏油剂量依赖性地降低了α-毒素、肠毒素 A 和 B（主要的葡萄球菌肠毒素）以及中毒性休克综合征毒素 1（TSST-1）在甲氧西林敏感金黄色葡萄球菌（MSSA）和耐甲氧西林金黄色葡萄球菌（MRSA）中的产生。
结论/意义：紫苏油降低了金黄色葡萄球菌中α-毒素、SEA、SEB 和 TSST-1 的产生。这些数据表明，紫苏油与β-内酰胺类抗生素联合使用时，可能对金黄色葡萄球菌感染的治疗有用，因为β-内酰胺类抗生素可以在亚抑菌浓度下增加金黄色葡萄球菌外毒素的产生。此外，紫苏油可以作为一种新型食品防腐剂在食品系统中合理应用，既能抑制金黄色葡萄球菌的生长，又能抑制外毒素的产生，特别是葡萄球菌肠毒素。
