In vitro Antibacterial Efficacy of Various Natural Rapeseed Honey against Some Gram-positive and Gram-negative Bacterial Strains

Abstract

With the ongoing threat of antibiotic resistance and the limitations of conventional antimicrobial therapies, honey represents a valuable natural alternative with the potential to complement existing treatment strategies and reduce the spread of resistant bacterial strains. Known to be rich in bioactive compounds, rapeseed honey is a promising alternative to traditional antibiotics amid growing concerns about antibiotic resistance. In the current study, in vitro antimicrobial profiling was performed on different natural rapeseed honeys produced by Polish manufacturers, which showed inhibitory activity against Gram-positive strains such as Staphylococcus aureus subsp. aureus Rosenbach ATCC^®25923™, Enterococcus faecalis (Andrewes and Horder) Schleifer and Kilpper-Balz ATCC^®29212™, vancomycin-susceptible Enterococcus faecalis (Andrewes and Horder) Schleifer and Kilpper-Balz ATCC^®51299™, and Gram-negative strains such as Pseudomonas aeruginosa (Schroeter) Migula ATCC^®27853™, Escherichia coli (Migula) Castellani and Chalmers ATCC^®25922™ and Escherichia coli (Migula) Castellani and Chalmers ATCC^®35218™. The antibacterial activity of rapeseed honeys was tested in vitro using the Kirby-Bauer disc diffusion technique. The results of our study showed that S. aureus subsp. aureus Rosenbach ATCC^®25923™, P. aeruginosa (Schroeter) Migula ATCC^®27853™ and E. faecalis (Andrewes and Horder) Schleifer and Kilpper-Balz ATCC^®51299™ strains were resistant to the different natural rapeseed honeys produced by Polish manufacturers. On the other hand, the E. faecalis (Andrewes and Horder) Schleifer and Kilpper-Balz ATCC^®29212™ strain was susceptible to some of the rapeseed honey samples tested. Similar trends were observed in the increase in the diameter of the inhibition zone after in vitro application of different natural rapeseed honeys against E. coli (Migula) Castellani and Chalmers ATCC^®35218™ strain, where we also observed a statistically significant increase in the zone of growth inhibition. Thus, the research highlights the potential of rapeseed honey as a valuable natural antimicrobial agent with broad-spectrum activity, offering a promising alternative to conventional antibiotics in the face of increasing antibiotic resistance.