COMPARATIVE STUDY OF SELECTED EGYPTIAN HONEYS AND THEIR ANTIBACTERIAL EFFECTS IN VITRO

Honey is a natural sweet substance known for its antimicrobial properties against a wide range of microorganisms.However, limited studies have investigated the physico-chemical and biological properties of different honey types from the same production region.This study evaluated six Egyptian floral and non-floral honeys (cotton, clover, citrus, eucalyptus, black seed, and spearmint) by assessing their physico-chemical composition, sugar and amino acid profiles, and antibacterial activity in vitro.Physicochemical parameters were analyzed using the Association of Official Analytical Chemists (AOAC) methods, the sugars by High Performance Liquid Chromatography (HPLC), and the amino acids by Gas-Liquid Chromatography (GLC).Honeys varied in pH between 3.80 and 4.20, moisture content between 17.0% and 19.5%, and total amino acid content between 7.84 and 17.19 mg/100 mg.Antibacterial activity at 5% and 10% concentrations was tested against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhimurium.Our findings showed that, compared to honeys from bee colonies fed medicinal plant extracts, floral honeys exhibited stronger antibacterial effects against both Gram-positive and Gram-negative bacteria.Cotton honey showed the highest activity, with inhibition zones up to 24.3 mm, while black seed honey was the least effective.Gram-positive bacteria were more susceptible than Gram-negative strains.Molecular assays revealed that honey exposure significantly reduced bacterial DNA, RNA, and protein levels.Cotton honey was the most potent at suppressing protein and RNA synthesis, particularly in B. subtilis, while black seed honey had a stronger effect on E. coli DNA.These results highlight the significant role of botanical origin in determining honey's antimicrobial efficacy and support the use of Egyptian monofloral honeys as natural antibacterial agents.