Investigating the antibacterial activity of oil palm leaf extracts against foodborne pathogens

Aims: Foodborne diseases result from consuming contaminated food and beverages, with their prevalence growing at an alarming rate worldwide.The emergence of antibiotic-resistant foodborne bacteria has led to the existing antibiotic treatment becoming ineffective, requiring the development of new antibacterial agents, preferably from natural origins.Due to this, our current study proposed using solvent extracts prepared from oil palm (Elaeis guineensis Jacq.) leaves as antibacterial agents with low toxicity to inhibit or kill foodborne bacteria, including Escherichia coli, Shigella flexneri, Salmonella Enteritidis, Listeria monocytogenes, Bacillus cereus, and Enterococcus faecalis.Methodology and results: Overall, the ethyl acetate (EA) and hexane oil palm leaf extracts (OPLE) demonstrated the highest inhibitory activity against all bacteria.The hexane OPLE recorded the lowest MIC value of 3.13 mg/mL against B. cereus, while the EA OPLE was found to be an effective antibacterial agent (MIC = 6.25 mg/mL) against E. faecalis and B. cereus, respectively.The EA (MBC = 6.25 mg/mL) and hexane (MBC = 3.13 mg/mL) OPLE were both bactericidal against B. cereus, while the EA OPLE was only bactericidal against E. faecalis at an MBC value of 25 mg/mL.The liquid chromatography-mass spectrometry (LCMS) analyses of the EA and hexane OPLE revealed the presence of alcohols, lipids, carboxylic acids, and amides. Conclusion, significance and impact of study:This study demonstrated that the oil palm leaves (OPL) may be a potential source of antibacterial agents against foodborne bacteria, particularly against Gram-positive bacteria.