Isolation and identification of antimicrobial compounds from the Australian medicinal plant 'Eremophila duttonii' (Scrophulariaceae)

The arid adapted genus 'Eremophila' features prominently in the Australian medical ethnobotanical literature with many citations describing traditional uses suggestive of antimicrobial activity, e.g. in the topical treatment of minor wounds, occular and otonasopharangeal complaints. In broad based screening programmes examining antibacterial activity of native indigenous medicinal plants, extracts of the species 'Eremophila duttonii' have been shown to consistently produce the greatest levels of activity amongst plants studies, both by this group and elsewhere. The genus is characterised phytochemically by the accumulation of structurally and stereochemically unusual terpenoids, unique tot he plant kingdom. Here we report on the isolation and identification of three compounds from a petroleum extract of 'Eremophila duttonii' exhibiting antibacterial activity against 'Staphylococcus aureus' and 'Candida albicans'.