Fungal diseases in humans have increased significantly with the advent of an expanding population of immunosuppressed patients and with the introduction of sophisticated life-saving medical procedures. Plant extracts and products have been used in traditional medicine for centuries. Coriaria nepalensis essential oil (CNEO) is known to possess antimicrobial activity. This study was an attempt to examine CNEO against various fluconazole-sensitive and -resistant Candida isolates. Insight into the mechanism of action was elucidated by flow cytometric analysis and ergosterol biosynthesis studies. The susceptibility tests for CNEO were carried out in terms of MIC and by disc diffusion assays against all Candida isolates, employing standard protocols. Insight into the mechanism of action was elucidated by propidium iodide cell sorting (FACS) and by assessing ergosterol content in treated and untreated isolates with the test entity. CNEO was found effective against all Candida isolates, including the resistant strains. While CNEO inflicts fungal cell death by disrupting membrane integrity, significant impairment of ergosterol biosynthesis was induced by the test entity. CNEO showed a strong antifungal effect against all the Candida isolates. Mechanisms of action appear to originate from the inhibition of ergosterol biosynthesis and the disruption of membrane integrity. It can be concluded that the observed antimicrobial characteristics of C. nepalensis indicate that it might be a promising antimicrobial agent. Copyright © 2011 John Wiley & Sons, Ltd.
