Honey can kill bacterial cells in various ways, including through hydrogen peroxide, acidity, osmotic effect, high sugar concentration, and polyphenols. In contrast to conventional antibiotics, honey does not target the essential growth processes of bacteria, which can result in the bacteria building up resistances to the drug. For example, the osmotic effect, resulting of the high sugar concentration in honey, draws water from the bacterial cells, dehydrating and killing them. However, the precise processes of the antimicrobial (antibacterial, antifungal, and antiviral) action of honey is not understood.
Susan M. Meschwitz and colleagues, Salve Regina University, Newport, RI, USA, have studied the activity of honey against bacteria including Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, trying to isolate some of the antimicrobial compounds. The studies show a correlation between the non-peroxide antimicrobial and antioxidant activities of honey and the presence of honey phenolics. Although the specific polyphenols found in honey vary with nectar source and region, the most common phenolics found in honey include the phenolic acids caffeic acid, p-coumaric acid, and ellagic acid and the flavonoids quercetin, apigenin, galangin, pinocembrin, kaempferol, luteolin, and chrysin.
Additionally, honey has been found to inhibit the formation of biofilms and may also disrupt quorum sensing, the way bacteria communicate with each other. Quorum sensing might be necessary for formation of biofilms and in some bacteria it controlls the release of toxins. However, the factors responsible for this inhibiting effect are still unclear.
To understand the unusual ability that honey has to fight infections, the team will investigated additional constituents of honey that may provide alternative modes of antibacterial action.
- Presented at the 247th National Meeting & Exposition of the American Chemical Society (ACS), Dallas, TX, USA