Biofilm-Associated Agr and Sar Quorum Sensing Systems of Are Inhibited by 3-Hydroxybenzoic Acid Derived from .

Biofilm-producing () is less sensitive to conventional antibiotics than free-living planktonic cells. Here, we evaluated the antibiofilm activity of () and one of its constituent compounds 3-hydroxybenzoic acid (3-HBA) against multi-drug-resistant . We performed gas chromatography-mass spectroscopy (GC-MS) to identify the major constituents in the methanolic extract of . Ligand-receptor interactions were studied by molecular docking, and investigations were performed using crystal violet assay, spreading assay, hemolysis, proteolytic activity, and growth curve analysis. The methanolic extract of inhibited at 4.8 mg/mL, and GC-MS analysis revealed anethole, m-methoxybenzaldehyde, and 3-HBA as the major constituents. Molecular docking attributed the antibiofilm activity to an active ligand present in 3-HBA, which strongly interacted with the active site residues of AgrA and SarA of . At a subinhibitory concentration of 2.4 mg/mL, the extract showed biofilm inhibition. Similarly, 3-HBA inhibited biofilm activity at 25 μg/mL (90.34%), 12.5 μg/mL (77.21%), and 6.25 μg/mL (62.69%) concentrations. Marked attrition in bacterial spreading was observed at 2.4 mg/mL (crude extract) and 25 μg/mL (3-HBA) concentrations. The methanol extract of and 3-HBA markedly inhibited β-hemolytic and proteolytic activities of . At the lowest concentration, the extract (2.4 mg/mL) and 3-HBA (25 μg/mL) did not inhibit bacterial growth. Optical microscopy and SEM analysis confirmed that and 3-HBA significantly reduced biofilm dispersion without disturbing bacterial growth. Together, we found that the antibiofilm activity of and 3-HBA strongly targeted the Agr and Sar systems of .