Biofilm inhibition by Cymbopogon citratus and Syzygium aromaticum essential oils in the strains of Candida albicans.
BACKGROUND
Oils of Cymbopogon citratus and Syzygium aromaticum have been used in traditional medicine to treat fungal infections of skin, mouth, urinary and vaginal tract in Asian countries particularly India and other developing countries.


OBJECTIVE
To evaluate essential oils of Cymbopogon citratus and Syzygium aromaticum for their anti-biofilm activity against strong biofilm forming strains of Candida albicans.


METHODS
XTT reduction assay, Time kill assays, light microscopy and scanning electron microscopy (SEM) were employed to determine the effect of test oils on the Candida albicans biofilms.


RESULTS
Most of the Candida albicans strains tested displayed formation of moderate to strong biofilms. Preformed Candida biofilms showed ≥1024 times increased resistance to antifungal drugs, 2 times to Syzygium aromaticum, but no increased tolerance for Cymbopogon citratus. Test oils were more active against preformed biofilms compared to amphotericin B and fluconazole. At 0.5× MIC, Cymbopogon citratus followed by Syzygium aromaticum were most inhibitory against biofilm formation. Light and electron microscopic studies revealed the deformity of three dimensional structures of biofilms formed in the presence of sub-MICs of Cymbopogon citratus. The cell membranes appeared to be the target site of compounds in sessile cells as displayed by SEM observations.


CONCLUSIONS
Our data had demonstrated promising in vitro anti-biofilm activity by Cymbopogon citratus and Syzygium aromaticum and confirm the ethnopharmacological use of these oils in muco-cutaneous Candida infections. Furthermore, it suggests exploitation of these oils as new anti-biofilm products to deal with the problem of drug-resistance and recurrent infection associated with biofilm mode of growth of Candida spp.
Department of Agricultural Microbiology, Aligarh Muslim University, Aligarh 202002, India.
Mohd Sajjad Ahmad
MS
Khan
Iqbal
I
Ahmad
D000666:Amphotericin B / Q000494:pharmacology; D000935:Antifungal Agents / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects*; D002176:Candida albicans / Q000187:drug effects*; D002177:Candidiasis / Q000188:drug therapy* / Q000382:microbiology; D002462:Cell Membrane / Q000187:drug effects; D031743:Cymbopogon / Q000737:chemistry*; D004351:Drug Resistance / Q000187:drug effects; D015725:Fluconazole / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D008853:Microscopy; D009822:Oils, Volatile / Q000494:pharmacology*; D008517:Phytotherapy; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D027842:Syzygium / Q000737:chemistry*
D000935:Antifungal Agents; D009822:Oils, Volatile; D010936:Plant Extracts; D000666:Amphotericin B; D015725:Fluconazole