Bioenergetic investigations on tea-tree and related essential oils

Direct and indirect calorimetry were used to determine the metabolic rates of the bacterium Escherichia coli and the baker's yeast Saccharomyces cerev isiae under the influence of five tea-tree oils and some of their constitue nts. Bacteriostatic and bactericidal as well as fungicidal effects were obs erved, dose-effect curves established, and the kinetics of the inactivation evaluated. Experiments showed that subpopulations of the E. coli suspensio ns were less sensitive against these essential oils than the whole populati on and were able to continue to metabolize and to grow. Some general information about tea-tree oils, their origin, application and composition is given. (C) 1999 Elsevier Science B.V, All rights reserved.