Antimicrobial activity of essential oils from Zieria

Essential oils, extracted from species of the genus Zieria using cold methanol extraction, were used to divide the Zieria species into eight groups based on the chemical compositions of their oils using hierarchical cluster analysis. The major components of most Zieria oils were oxygenated terpenes or other related compounds including car-3-en-2-one, chrysanthenone, eucarvone, methyl eugenol, elemicin and safrole. In several of the Zieria oils the major oxygenated monoterpene made up between 50-60% of the oil composition. Measurements of minimum inhibitory concentration, using an agar dilution method and E. coli, Staph. aureus, Ps. aeruginosa and C. albicans as test organisms, have demonstrated that essential oils from Zieria exhibit antimicrobial activity. Several of the major oxygenated compounds were tested individually and found, in most cases, to be comparable in bioactivity to the oils in which they occurred.