Evaluation of the Antibacterial Activity of Cinnamic Acid and Its Derivatives: Synergistic Effects with Cloxacillin

Staphylococcus epidermidis is a widely prevalent microorganism whose key virulence factors include a high ability to adhere to synthetic surfaces and the capacity to form biofilms. The widespread distribution of multidrug-resistant strains (e.g., MRSE-methycillin-resistant Staphylococcus epidermidis) compels researchers to explore new therapeutic approaches. Cinnamic acid and its derivatives are common plant-derived compounds known for their broad range of biological activities, including antimicrobial properties. The phenotypic assays conducted in this study revealed a strong anti-biofilm activity of the investigated compounds. Confocal laser scanning microscopy allowed for the visualization of structural changes within the biofilm and facilitated the assessment of bacterial cell viability in relation to the concentration of the tested substances.