Pectolinarin Inhibits the Bacterial Biofilm Formation and Thereby Reduces Bacterial Pathogenicity.

Bacterial biofilms are a growing problem as it is a major cause of nosocomial infection from urinary catheters to chronic tissue infections and provide resistance to a variety of antibiotics and the host's immune system. The effect of pectolinarin on the biofilm formation in Enterococcus faecalis , Enterococcus faecium , Escherichia coli , Streptococcus mutans , Streptococcus sobrinus , Staphylococcus aureus , Pseudomonas aeruginosa , Cutibacterium acnes , and Porphyromonas gingivalis was studied in TSBg (tryptic soy broth supplemented with 1% glucose). Pectolinarin inhibited biofilm formation of E. faecalis (IC 50 = 0.39 μg/mL), E. faecium (IC 50 = 0.19 μg/mL), E. coli (IC 50 = 0.25 μg/mL), S. mutans (IC 50 = 1.2 μg/mL), S. sobrinus (IC 50 = 1.4 μg/mL), S. aureus (IC 50 = 0.39 μg/mL), P. aeruginosa (IC 50 = 0.9 μg/mL), P. acnes (IC 50 = 12.5 μg/mL), and P. gingivalis (IC 50 = 9.0 μg/mL) without inhibiting the bacterial growth. Pectolinarin also showed increased susceptibility of antibacterial activity with commercially available antibiotics including ampicillin, vancomycin, streptomycin, and oxytetracyclin against E. faecalis and E. faecium . Finally, pectolinarin dose-dependently reduced the expression of genes including cytolysin genes ( cylLS , cylR2 and cylM ), quorum sensing (QS) genes ( fsrB , fsrC , gelE , ebpA , ebpB , acm , scm and bps ), and biofilm virulence genes ( esp ) of E. faecalis and E. faecium . Pectolinarin reduced the bacterial biofilm formation, activated the antibacterial susceptibility, and reduced the bacterial adherence. These results suggest that bacterial biofilm formation is a good target to develop the antibacterial agents against biofilm-related infections.