Liquid and vapour-phase antifungal activities of selected essential oils against candida albicans: microscopic observations and chemical characterization of cymbopogon citratus

Abstract

BackgroundUse of essential oils for controlling Candida albicans growth has gained significance due to the resistance acquired by pathogens towards a number of widely-used drugs. The aim of this study was to test the antifungal activity of selected essential oils against Candida albicans in liquid and vapour phase and to determine the chemical composition and mechanism of action of most potent essential oil.MethodsMinimum Inhibitory concentration (MIC) of different essential oils in liquid phase, assayed through agar plate dilution, broth dilution & 96-well micro plate dilution method and vapour phase activity evaluated through disc volatilization method. Reduction of C. albicans cells with vapour exposure was estimated by kill time assay. Morphological alteration in treated/untreated C. albicans cells was observed by the Scanning electron microscopy (SEM)/Atomic force microscopy (AFM) and chemical analysis of the strongest antifungal agent/essential oil has been done by GC, GC-MS.ResultsLemon grass (Cymbopogon citratus) essential oil exhibited the strongest antifungal effect followed by mentha (Mentha piperita) and eucalyptus (Eucalyptus globulus) essential oil. The MIC of lemon grass essential oil in liquid phase (288 mg/l) was significantly higher than that in the vapour phase (32.7 mg/l) and a 4 h exposure was sufficient to cause 100% loss in viability of C. albicans cells. SEM/AFM of C. albicans cells treated with lemon grass essential oil at MIC level in liquid and vapour phase showed prominent shrinkage and partial degradation, respectively, confirming higher efficacy of vapour phase. GC-MS analysis revealed that lemon grass essential oil was dominated by oxygenated monoterpenes (78.2%); α-citral or geranial (36.2%) and β-citral or neral (26.5%), monoterpene hydrocarbons (7.9%) and sesquiterpene hydrocarbons (3.8%).ConclusionLemon grass essential oil is highly effective in vapour phase against C. albicans, leading to deleterious morphological changes in cellular structures and cell surface alterations.

Potential of Herbal Drug and Antibiotic Combination Therapy: A New Approach to Treat Multidrug Resistant Bacteria

“…The active components of the cinnamon oil are cinnamaldehyde [88], ethyl cinnamate, eugenol, β-caryophyllene, and linalool and methyl chavicol [89]. The cinnamon oil is rich in transcinnamaldehyde with antimicrobial effects against animal and plant pathogens, food poisoning and spoilage bacteria and fungi [90,91]. Cinnamon barks and leaves are used as flavoring agent in foods and also for the medicinal purpose [92].…”

Chemical composition, antibacterial and antifungal activities of Saudi Arabian Mentha longifolia L. essential oil

“…The essential oils of Mentha longifolia L. (M. longifolia) have been extensively investigated, as evident in a large number of studies focusing on their antiviral, antimicrobial, antifungal [10][11][12], antibiofilm formation [13][14][15], radioprotective [16,17], antioedema, analgesic and antioxidant properties [13].…”

Plasma membrane damage contributes to antifungal activity of citronellal against Penicillium digitatum

“…The permeability and integrity of cell plasma membrane serve important functions in maintaining fungal viability (Paul et al 2011;Tao et al 2014a). Previous studies have shown that the lipophilicity of essential oils enables them to preferentially partition from an aqueous phase into membrane structures of the fungi, resulting in membrane expansion, increased membrane fluidity and permeability, disturbance of membrane-embedded proteins, inhibition of respiration, alteration of ion transport processes in fungi and induced the leakage of other cellular contents (Tao et al 2014b;Tyagi and Malik 2010;Zhou et al 2014). In the current research, the results of PI staining and microscopy showed that the membrane integrity of P. digitatum spores obviously declined after citronellal treatment (Fig.…”