Aswathanarayan Jamuna Bai, Vittal Ravishankar Rai
Department of Studies in Microbiology, University of Mysore Mysore India
RSC Adv. 2018 Oct 23;8(63):36133-36141. doi: 10.1039/c8ra06413j. eCollection 2018 Oct 22.
Quorum sensing is involved in biofilm formation and modulates virulence factor production in pathogenic bacteria. Quorum sensing inhibitors can be used as novel intervention strategies for attenuating bacterial pathogenicity. Berberine is an isoquinoline alkaloid with pharmacological properties. The present study investigated the sub-inhibitory concentrations of berberine for inhibiting biofilm formation and quorum sensing regulated phenotypes in the bacterial pathogens PA01 and serovar Typhimurium. Berberine inhibited quorum sensing regulated violacein production in . It reduced the pigment production in the wild type strain at 1.6 mg mL by 62.67%. In the opportunistic pathogen, PA01, at sub-MIC, it showed significant antibiofilm activity in by reducing biomass by 71.70% ( < 0.05). It prevented biofilm formation and inactivated biofilm maturation in bacterial pathogens at the concentration ranging from 0.019 to 1.25 mg mL. studies showed that berberine interacted with the quorum sensing signal receptors, LasR and RhlR. Furthermore, its anti-infective properties in . Typhimurium were studied. At sub-inhibitory concentrations of 0.019 mg mL, it reduced biofilm formation in . Typhimurium by 31.20%. It significantly prevented invasion and adhesion of invasion in the colonic cell, HT 29 by 55.37% and 54.68%, respectively. It was capable of reducing virulence in infected with at 0.038 mg mL by 65.38%. Our results suggest that berberine, previously recognised for its antimicrobial activity, could find potential application as an anti-biofilm and anti-infective agent based on its quorum sensing inhibitory activity.
群体感应参与生物膜形成，并调节病原菌中致病因子的产生。群体感应抑制剂可用作减弱细菌致病性的新型干预策略。黄连素是一种具有药理特性的异喹啉生物碱。本研究调查了黄连素在亚抑制浓度下对细菌病原体PA01和鼠伤寒血清型菌株生物膜形成及群体感应调节表型的抑制作用。黄连素抑制群体感应调节的紫色杆菌素产生。在1.6 mg/mL时，它使野生型菌株的色素产生减少了62.67%。在机会致病菌PA01中，在亚最小抑菌浓度下，它通过减少71.70%的生物量显示出显著的抗生物膜活性（P<0.05）。在0.019至1.25 mg/mL的浓度范围内，它可防止细菌病原体形成生物膜并使生物膜成熟失活。研究表明，黄连素与群体感应信号受体LasR和RhlR相互作用。此外，还研究了其在鼠伤寒沙门氏菌中的抗感染特性。在0.019 mg/mL的亚抑制浓度下，它使鼠伤寒沙门氏菌的生物膜形成减少了31.20%。它分别显著阻止了鼠伤寒沙门氏菌对结肠细胞HT-29的侵袭和黏附，侵袭减少了55.37%，黏附减少了54.68%。在0.038 mg/mL时，它能够使感染鼠伤寒沙门氏菌的小鼠的毒力降低65.38%。我们的结果表明，黄连素此前因其抗菌活性而被认可，基于其群体感应抑制活性，它可能作为一种抗生物膜和抗感染剂找到潜在应用。
