Causes of the antimicrobial activity of honey.

The present study was performed to clarify the possible causes of the antimicrobial activity of honey. A sugar solution resembling honey in its high sugar content was made. The antimicrobial activities of both honey and this solution towards 21 types of bacteria and two types of fungi were examined. The results achieved by both were compared. The difference between them indicated the presence of antimicrobial substance(s) in honey. The kinds of antimicrobial substances (inhibines) in honey are discussed. Hydrogen peroxide is not the only inhibine in honey. In fact, inhibines in honey include many other substances. Two important classes of these inhibines are the flavonoids and the phenolic acids. Flavonoids have often been extracted from honey previously. In this study two phenolic acids (caffeic acid and ferulic acid) were extracted from honey for the first time.