Morin inhibits biofilm production and reduces the virulence of Listeria monocytogenes — An in vitro and in vivo approach

• Published in: International journal of food microbiology 2016-11, Vol.237, p.73-82
• Main Authors: Sivaranjani, Murugesan, Gowrishankar, Shanmugaraj, Kamaladevi, Arumugam, Pandian, Shunmugiah Karutha, Balamurugan, Kirshnaswamy, Ravi, Arumugam Veera
• Format: Article
• Language: English
• Subjects: Animals; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Biofilm; Biofilms - drug effects; Caenorhabditis elegans; Flavonoids - pharmacology; Hemolysin; Humans; Listeria monocytogenes; Listeria monocytogenes - drug effects; Listeria monocytogenes - genetics; Listeria monocytogenes - pathogenicity; Listeria monocytogenes - physiology; Listeriosis - drug therapy; Listeriosis - microbiology; Microbial Sensitivity Tests; Morin; Motility; Virulence - drug effects
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2016.08.021

The current study explores the in vitro and in vivo antibiofilm efficacy of morin against a leading foodborne pathogen-Listeria monocytogenes (LM). Minimum inhibitory concentration (MIC) of morin against LM strains was found to be 100μg/ml. The non-antibacterial effect of morin at its sub-MICs (6.25, 12.5 and 25μg/ml) was determined through growth curve and XTT assay. Morin at its sub-MICs demonstrated a significant dose dependent inhibitory efficacy against LM biofilm formation which was also evidenced through light, confocal and scanning electron microscopic analyses. However, morin failed to disperse the mature biofilm of LM even at its MIC. Our data also revealed the anti-virulence efficacy of morin, as it significantly inhibited the production of hemolysin and motility of LM. Concentration-dependent susceptibility of morin treated LM cells to normal human serum was observed. In vivo studies revealed that morin extended the lifespan of LM infected Caenorhabditis elegans by about 85%. Furthermore, the non-toxic nature and in vivo anti-adherence efficacy of morin were also ascertained through C. elegans-LM infection model. Overall, the data of the current study identifies morin as a promising antibiofilm agent and its suitability to formulate protective strategies against biofilm associated infections caused by LM. •Morin was used at sub-MICs that do not possess any anti-listerial property.•In in vitro, morin effectively inhibited the initial biofilm formation of Listeria monocytogenes (LM) strains.•Morin at its sub-MICs significantly reduced the killing of LM infected C. elegans without affecting the LM growth.•At sub-MICs of morin dose dependently decreased the intestinal colonization of LM in C. elegans without affecting the bacterial growth.•The non-toxic nature of morin increased the survival rate of C. elegans against LM infection.