A study of antibacterial activity and mechanism of potassium cinnamate intended as a natural preservative

The increasing aware of the potential adverse effects of chemical preservatives has necessitated the exploration of natural alternatives. Cinnamic acid is a natural active compound with antibacterial properties. This study investigated the antibacterial activity and mechanism of potassium cinnamate against four foodborne pathogenic bacteria ( Staphylococcus aureus , Escherichia coli , Bacillus cereus , and Shigella boydii ), with the aim of using it as a natural preservative. The minimum inhibitory and bactericidal concentrations of potassium cinnamate were 1–4 and 8–16 mg/mL, respectively. Potassium cinnamate inhibited biofilm formation, triggered intracellular reactive oxygen species increases, and damaged cell membranes, nucleic acids, and proteins, thus disrupting energy synthesis. Additionally, it disrupted cell membrane integrity, causing cellular content leakage and death. Following treatment with potassium cinnamate, RNA-sequencing revealed that B. cereus significantly differentially expressed 1186 genes. Among these, membrane and plasma membrane-associated genes show the most prominent response, the downregulated genes are mainly related to quorum sensing, energy metabolism and amino acid metabolism. Based on hemolysis and cytotoxicity tests, potassium cinnamate is safe at effective bacterial inhibitory concentrations. Therefore, potassium cinnamate is a potential natural preservative that is applicable in the food industry. • Potassium cinnamate exerts antibacterial activity against four foodborne pathogens. • It inhibited biofilm formation of foodborne pathogens. • It damaged cell membrane, nucleic acids, proteins, and energy synthesis of strains. • RNA-sequencing revealed the antibacterial mechanism at the level of gene expression. • Hemolysis and cytotoxicity tests shown potassium cinnamate has good biosafety.