Abstract Benzyl isocyanate (BIC), from methanol extract of Psidium guajava leaves, exhibited substantial anti-biofilm activities against Staphylococcus aureus, the common bacterial pathogen in nosocomial infections. Major components of the extract included eugenol, BIC, phenyl-2-methoxy-4-(1-propenyl)-acetate and 2,5-pyrrolidinedione,1-penta-3-4-dienyl, analyzed by GC-MS and HPLC studies. BIC exhibited substantial anti-biofilm activitiy against S. aureus, established by assaying biofilm formation, biofilm metabolic activity, bacterial adherence to hydrocarbons, exopolysaccharide formation, and optical and scanning electron microscopic studies. BIC significantly downregulated the important biofilm markers of S. aureus, viz., icaAD, sarA and agr, observed by quantitative real time polymerase chain reaction analysis. Molecular docking studies revealed thermodynamically favorable interaction of BIC with IcaA, SarA and Agr, having Gibbs energy values of −8.45, −9.09 and −10.29 kcal mol−1, respectively. BIC after binding to IcaR, the repressor of IcaA, influences its binding to target DNA site (Eshape, −157.27 kcal mol−1). The results are considered to demonstrate anti-biofilm potential of BIC against bacterial infections.

中文翻译：

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从番石榴叶中分离的异氰酸苄酯抑制金黄色葡萄球菌生物膜形成

摘要 来自番石榴叶甲醇提取物的异氰酸苄酯 (BIC) 对金黄色葡萄球菌（医院感染中的常见细菌病原体）具有显着的抗生物膜活性。提取物的主要成分包括丁香酚、BIC、苯基-2-甲氧基-4-(1-丙烯基)-乙酸酯和 2,5-吡咯烷二酮、1-penta-3-4-二烯基，通过 GC-MS 和 HPLC 研究进行分析. BIC 对金黄色葡萄球菌具有显着的抗生物膜活性，这是通过测定生物膜形成、生物膜代谢活性、细菌对碳氢化合物的粘附、胞外多糖形成以及光学和扫描电子显微镜研究确定的。通过定量实时聚合酶链反应分析观察到，BIC 显着下调了金黄色葡萄球菌的重要生物膜标志物，即 icaAD、sarA 和 agr。分子对接研究揭示了 BIC 与 IcaA、SarA 和 Agr 的热力学有利相互作用，吉布斯能量值分别为 -8.45、-9.09 和 -10.29 kcal mol-1。BIC 与 IcaA 的阻遏物 IcaR 结合后，会影响其与目标 DNA 位点的结合（Eshape，-157.27 kcal mol-1）。结果被认为证明了 BIC 对细菌感染的抗生物膜潜力。