Methicillin-resistant Staphylococcus (S.) aureus (MRSA) is a representative pathogen that produces numerous virulence factors involving manifold cytotoxins and exotoxins. The present study was designed to investigate the influence of Eleutheroside K (ETSK), a single compound isolated from the leaves of Acanthopanax (A.) henryi (Oliv.) Harms, on the exotoxins secreted by MRSA. The transcription and translation of the exotoxins (α-hemolysin and staphylococcal enterotoxins) related to virulence in S. aureus were determined via quantitative RT-PCR and western blot analysis. The effect of ETSK on the production of tumor necrosis factor (TNF)-α was evaluated using enzyme-linked immunosorbent assay. As a result, ETSK at sub-MIC concentrations could reduce the protein expression of α-hemolysin and enterotoxin, and the expression of genes that regulate virulence factors was also inhibited. In addition, the TNF-inducing activity of S. aureus was attenuated by ETSK in a dose-dependent manner. These results revealed that ETSK not only reduced the protein and gene expression levels of related exotoxins but also suppressed the ability of S. aureus to induce macrophages to release cytokines. This study indicated that the inhibition of MRSA infection by ETSK may be achieved by reducing the virulence of S. aureus and highlighted the potential of ETSK as an innovative strategy for the prevention and treatment of MRSA infections.

耐甲氧西林金黄色葡萄球菌( S. )金黄色葡萄球菌(MRSA) 是一种具有代表性的病原体，可产生多种毒力因子，包括多种细胞毒素和外毒素。本研究旨在调查刺五加( A. ) henryi (Oliv.) Harms 叶子中分离的单一化合物刺五加苷 K (ETSK) 对 MRSA 分泌的外毒素的影响。与金黄色葡萄球菌毒力相关的外毒素（α-溶血素和葡萄球菌肠毒素）的转录和翻译通过定量RT-PCR和蛋白质印迹分析确定。使用酶联免疫吸附试验评估 ETSK 对肿瘤坏死因子 (TNF)-α 产生的影响。结果，亚MIC浓度的ETSK可以降低α-溶血素和肠毒素的蛋白质表达，并且调节毒力因子的基因的表达也受到抑制。此外，ETSK 以剂量依赖性方式减弱了金黄色葡萄球菌的 TNF 诱导活性。这些结果表明，ETSK不仅降低了相关外毒素的蛋白质和基因表达水平，而且还抑制了金黄色葡萄球菌的能力。诱导巨噬细胞释放细胞因子。该研究表明，ETSK 可通过降低金黄色葡萄球菌的毒力来抑制 MRSA 感染，并强调了 ETSK 作为预防和治疗 MRSA 感染的创新策略的潜力。