Vegetable and Fruit Improvement Center, Department of Horticultural Sciences, Texas A&M University, College Station, TX, USA.
Department of Poultry Science, Texas A&M University, College Station, TX, USA.
J Appl Microbiol. 2010 Aug;109(2):515-527. doi: 10.1111/j.1365-2672.2010.04677.x. Epub 2010 Jan 19.
This study investigated the quorum sensing, biofilm and type three secretion system (TTSS) inhibitory properties of citrus flavonoids.
Flavonoids were tested for their ability to inhibit quorum sensing using Vibrio harveyi reporter assay. Biofilm assays were carried out in 96-well plates. Inhibition of biofilm formation in Escherichia coli O157:H7 and V. harveyi by citrus flavonoids was measured. Furthermore, effect of naringenin on expression of V. harveyi TTSS was investigated by semi-quantitative PCR. Differential responses for different flavonoids were observed for different cell-cell signalling systems. Among the tested flavonoids, naringenin, kaempferol, quercetin and apigenin were effective antagonists of cell-cell signalling. Furthermore, these flavonoids suppressed the biofilm formation in V. harveyi and E. coli O157:H7. In addition, naringenin altered the expression of genes encoding TTSS in V. harveyi.
The results of the study indicate a potential modulation of bacterial cell-cell communication, E. coli O157:H7 biofilm and V. harveyi virulence, by flavonoids especially naringenin, quercetin, sinensetin and apigenin. Among the tested flavonoids, naringenin emerged as potent and possibly a nonspecific inhibitor of autoinducer-mediated cell-cell signalling. Naringenin and other flavonoids are prominent secondary metabolites present in citrus species. Therefore, citrus, being a major source of some of these flavonoids and by virtue of widely consumed fruit, may modulate the intestinal microflora.
Currently, a limited number of naturally occurring compounds have demonstrated their potential in inhibition of cell-cell communications; therefore, citrus flavonoids may be useful as lead compounds for the development of antipathogenic agents.
本研究调查了柑橘类黄酮的群体感应、生物膜和 III 型分泌系统（TTSS）抑制特性。
使用哈维弧菌报告测定法测试了黄酮类化合物抑制群体感应的能力。在 96 孔板中进行生物膜测定。测量了柑橘类黄酮对大肠杆菌 O157:H7 和哈维弧菌生物膜形成的抑制作用。此外，通过半定量 PCR 研究了柚皮苷对哈维弧菌 TTSS 表达的影响。不同的黄酮类化合物对不同的细胞间信号系统表现出不同的反应。在所测试的黄酮类化合物中，柚皮苷、山奈酚、槲皮素和芹菜素是细胞间信号的有效拮抗剂。此外，这些黄酮类化合物抑制了哈维弧菌和大肠杆菌 O157:H7 的生物膜形成。此外，柚皮苷改变了哈维弧菌中编码 TTSS 的基因的表达。
该研究结果表明，黄酮类化合物，特别是柚皮苷、槲皮素、橙皮素和芹菜素，可能通过调节细菌细胞间通讯、大肠杆菌 O157:H7 生物膜和哈维弧菌毒力来发挥作用。在所测试的黄酮类化合物中，柚皮苷作为一种潜在的非特异性自动诱导细胞间信号转导抑制剂脱颖而出。柚皮苷和其他类黄酮是柑橘类水果中存在的主要次生代谢产物。因此，柑橘作为这些类黄酮的主要来源之一，由于其广泛食用的水果特性，可能会调节肠道微生物群。
目前，只有少数天然存在的化合物显示出抑制细胞间通讯的潜力；因此，柑橘类黄酮可能是开发抗病原体药物的有用先导化合物。
