Antibiofilm Efficacy of Curcumin: FTIR Spectroscopy and Molecular Docking Evidence for Matrix Disruption in Bovine Mastitis Pathogens

Bovine mastitis, an inflammatory condition of the mammary gland predominantly caused by microbial infection, remains a substantial challenge to global dairy production.Although the broad-spectrum antibacterial activity of curcumin is well-documented, its precise mechanisms of action against the extracellular matrix of mastitis-associated biofilms are poorly understood.This study evaluated the efficacy of curcumin against biofilms formed by three key mastitis pathogens Staphylococcus aureus, Streptococcus dysgalactiae, and Escherichia coli, and characterized its ability to alter the biochemical architecture of the biofilm matrix.We assessed the antibiofilm efficacy of curcumin using biofilm formation, dispersion, and membrane leakage assays.Fourier-transform infrared (FTIR) spectroscopy was employed to determine the associated biochemical changes in the biofilm matrix, and molecular docking analysis was performed to evaluate the potential binding of curcumin to selected biofilm matrix proteins.Curcumin significantly (p < 0.05) inhibited biofilm formation, promoted the dispersion of mature biofilms, and induced biomolecule leakage.FTIR analysis of S. aureus and S. dysgalactiae biofilms treated with 600 µg/mL curcumin showed spectral alterations in regions associated with lipids (2800-3000 cm⁻¹), proteins (Amide I & II, 1600-1700 cm⁻¹ & 1480-1575 cm⁻¹), nucleic acids (1450-1200 cm⁻¹), and carbohydrates (1150-1000 cm⁻¹).For E. coli, spectral changes occurred in regions associated with lipids, proteins, and nucleic acids, but not carbohydrates.Molecular docking revealed that curcumin exhibited strong binding affinity for the biofilmassociated aminopeptidases from S. dysgalactiae (A0A380JWY5), E. coli (P04825), and S. aureus (Q6GIP8) with Vina scores of -7.6 kcal/mol, -8.2 kcal/mol, and -7.4 kcal/mol, respectively.These findings demonstrate that the antibiofilm activity of curcumin is mediated through the targeted disruption of the extracellular matrix in mastitis pathogens, offering new insights into its potential therapeutic applications.