Department of Pharmacology, Toxicology and Therapeutics, School of Medicine, The University of Kansas Medical Center, The University of Kansas, Kansas City, 66160 KS, USA.
Department of Mycology and Plant Pathology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi-211 005, India.
Microbiology (Reading). 2012 Feb;158(Pt 2):529-538. doi: 10.1099/mic.0.052985-0. Epub 2011 Nov 24.
Lagerstroemia speciosa (Lythraceae) is a south-east Asian tree more commonly known as 'Jarul'. Research on health benefits suggests that the L. speciosa plant contains phytomolecules that may have antioxidant, anti-diabetic and anti-obesity properties. However, antimicrobial activities have not been reported for this plant. The ability of L. speciosa fruit extract (LSFE) to antagonize cell-to-cell communication, expression of virulence genes and factors, and biofilm formation was evaluated in Pseudomonas aeruginosa strain PAO1. Our results suggested that LSFE caused downregulation of quorum sensing (QS)-related genes (las and rhl) and their respective signalling molecules, N-acylhomoserine lactones, without affecting the growth of P. aeruginosa PAO1. Significant inhibition of virulence factors: LasA protease, LasB elastase, and pyoverdin production, was also recorded. Application of LSFE to P. aeruginosa PAO1 biofilms increased bacterial susceptibility to tobramycin. These data suggest a possible role for quorum-quenching mechanisms unrelated to static or cidal effects, and also suggest that L. speciosa could serve as a cost-effective source in the development of new QS-based antibacterial drugs.
紫薇（千屈菜科）是一种常见于东南亚的树木，通常被称为“Jarul”。研究表明，紫薇植物含有可能具有抗氧化、抗糖尿病和抗肥胖特性的植物分子。然而，尚未报道该植物具有抗菌活性。评估了紫薇果实提取物（LSFE）对铜绿假单胞菌 PAO1 细胞间通讯、毒力基因和因子表达以及生物膜形成的拮抗作用。结果表明，LSFE 导致群体感应（QS）相关基因（las 和 rhl）及其各自的信号分子 N-酰基高丝氨酸内酯下调，而不影响铜绿假单胞菌 PAO1 的生长。还记录了毒力因子 LasA 蛋白酶、LasB 弹性蛋白酶和吡咯并啉产量的显著抑制。LSFE 应用于铜绿假单胞菌 PAO1 生物膜增加了细菌对妥布霉素的敏感性。这些数据表明，与静态或杀菌作用无关的群体感应淬灭机制可能发挥作用，并且紫薇可以作为开发基于 QS 的新型抗菌药物的具有成本效益的来源。
