Antibacterial phenolic components of New Zealand manuka honey

This paper describes several methods for isolation of the antibacterially a ctive phenolic fraction of honey derived from the native New Zealand manuka tree, Leptospermum scoparium (Myrtaceae). This fraction consists of phenol ic derivatives of benzoic acids, cinnamic acids and flavonoids, all of whic h have been identified previously in honeys which do not exhibit non-peroxi de residual antibacterial activity. The flavonoids had not previously been identified in manuka honey. Furthermore, the flavonoids were different from those found in the leaves of manuka trees but were the same as those found in European honeys and propolis. While most of these phenolic products pos sess antibiotic activity, they do not individually or collectively account for the antibacterial activity of 'active' manuka honey. Essentially all of this activity is associated with the carbohydrate fraction of the honey. ( C) 1998 Elsevier Science Ltd. All rights reserved.