Vasavi Halkare Suryanarayana, Arun Ananthapadmanabha Bhagwath, Rekha Punchapady-Devasya
Yenepoya Research Centre, Yenepoya University, University Road, Nityananda Nagar, Deralakatte, Mangalore 575018, Karnataka, India.
Microbiol Immunol. 2014 May;58(5):286-93. doi: 10.1111/1348-0421.12150.
Psidium guajava L., which has been used traditionally as a medicinal plant, was explored for anti-quorum sensing (QS) activity. The anti-QS activity of the flavonoid (FL) fraction of P. guajava leaves was determined using a biosensor bioassay with Chromobacterium violaceum CV026. Detailed investigation of the effects of the FL-fraction on QS-regulated violacein production in C. violaceum ATCC12472 and pyocyanin production, proteolytic, elastolytic activities, swarming motility and biofilm formation in Pseudomonas aeruginosa PAO1 was performed using standard methods. Possible mechanisms of QS-inhibition were studied by assessing violacein production in response to N-acyl homoserine lactone (AHL) synthesis in the presence of the FL-fraction in C. violaceum ATCC31532 and by evaluating the induction of violacein in the mutant C. violaceum CV026 by AHL extracted from the culture supernatants of C. violaceum 31532. Active compounds in the FL-fraction were identified by liquid chromatography-mass spectrometry (LC-MS). Inhibition of violacein production by the FL-fraction in a C. violaceum CV026 biosensor bioassay indicated possible anti-QS activity. The FL-fraction showed concentration-dependent decreases in violacein production in C. violaceum 12472 and inhibited pyocyanin production, proteolytic and elastolytic activities, swarming motility and biofilm formation in P. aeruginosa PAO1. Interestingly, the FL-fraction did not inhibit AHL synthesis; AHL extracted from cultures of C. violaceum 31532 grown in the presence of the FL-fraction induced violacein in the mutant C. violaceum CV026. LC-MS analysis revealed the presence of quercetin and quercetin-3-O-arabinoside in the FL-fraction. Both quercetin and quercetin-3-O-arabinoside inhibited violacein production in C. violaceum 12472, at 50 and 100 μg/mL, respectively. Results of this study provide scope for further research to exploit these active molecules as anti-QS agents.
番石榴（Psidium guajava L.）传统上被用作药用植物，本研究对其进行了群体感应（QS）抑制活性的探索。采用紫色杆菌CV026生物传感器生物测定法测定了番石榴叶黄酮（FL）组分的抗QS活性。使用标准方法详细研究了FL组分对紫色杆菌ATCC12472中QS调控的紫菌素产生以及铜绿假单胞菌PAO1中绿脓菌素产生、蛋白水解活性、弹性蛋白酶活性、群游运动和生物膜形成的影响。通过评估在紫色杆菌ATCC31532中存在FL组分时对N-酰基高丝氨酸内酯（AHL）合成的响应中紫菌素的产生，以及通过评估从紫色杆菌31532培养上清液中提取的AHL对突变体紫色杆菌CV026中紫菌素的诱导，研究了QS抑制的可能机制。通过液相色谱-质谱联用（LC-MS）鉴定了FL组分中的活性化合物。在紫色杆菌CV026生物传感器生物测定中，FL组分对紫菌素产生的抑制表明其可能具有抗QS活性。FL组分在紫色杆菌12472中使紫菌素产生呈浓度依赖性降低，并抑制了铜绿假单胞菌PAO1中绿脓菌素的产生、蛋白水解和弹性蛋白酶活性、群游运动和生物膜形成。有趣的是，FL组分不抑制AHL的合成；从在FL组分存在下生长的紫色杆菌31532培养物中提取的AHL可诱导突变体紫色杆菌CV026中产生紫菌素。LC-MS分析显示FL组分中存在槲皮素和槲皮素-3-O-阿拉伯糖苷。槲皮素和槲皮素-3-O-阿拉伯糖苷分别在50和100μg/mL时抑制紫色杆菌12472中紫菌素的产生。本研究结果为进一步研究开发这些活性分子作为抗QS剂提供了空间。
