Antimicrobial Activity of Honey and Characterization of Its Bioactive Compounds in Comparison With Important Commercial Honeys.

There is an urgent need for new effective antimicrobial agents since acquired resistance of bacteria to currently available agents is increasing. The antimicrobial activity of Mono-floral honey produced from Australian grown was compared with the activity of commercially available honeys derived from species and with Jarrah honey for activity against clinical and non-clinical strains of (methicillin-susceptible and methicillin-resistant strains), , and . The minimum inhibitory concentration (MIC) for honey was in the range of 6-25% (w/v) for all species examined. The MICs for honeys were generally similar to those of honey, but MICs were higher for Super manuka and Jarrah honeys and lower for Tea tree honey. Staphylococci were more susceptible to all honeys than and . Pretreatment of honey with catalase increased the bacterial growth at MIC of Tea tree honey (35%), Super Manuka (15%), Jarrah honeys (12%), and honey (10%), indicating variable contributions of hydrogen peroxide to antimicrobial activity. Manuka and Jelly bush honeys retained their antimicrobial activity in the presence of catalase, indicating the presence of other antimicrobial compounds in the honey. An LC-MS/MS method was developed and used to identify possible antimicrobial phenolic compounds in honey and flowers, and five commercial honeys. The chemical markers characteristic of honey and honeys of origin were phenyllactic acid and methyl syringate. Overall, the bioactive compounds with antimicrobial and antioxidant activity in honey suggested a possible use for topical application and in wound care.