Mechanistic insights into Candida biofilm eradication potential of eucalyptol

Candida-associated fungal infections are prevalent in hospitalized and immune-compromised patients. Their biofilm architecture and high rate of antifungal resistance make treatment challenging. Eucalyptol (EPTL), a monoterpene majorly present in the essential oil of eucalyptus is well known for curing respiratory infections. Hence, the present study investigated the anti-biofilm efficacy of EPTL against the laboratory strains and clinical isolates of Candida to delineate its mode of action.

The effect of EPTL on the viability, biofilm formation, and mature biofilm of Candida strains was studied. Furthermore, its effect on cell cycle arrest, mitochondrial membrane potential (MMP), ROS generation, germ tube formation, ergosterol content and transcriptional expression of selected genes was also investigated.

EPTL exhibited anti-biofilm activity against mature and developing biofilm of Candida albicans and Candida glabrata along with their clinical isolates. The biochemical components and enzyme activity were differentially modulated in EPTL-treated biofilm extracellular matrix. EPTL generated ROS and arrested cell cycle at the G₁ /S phase in both the species, while altered MMP was recorded in C. glabrata. Transcriptional analysis evidenced for differential gene expression of selected ABC transporters, secreted hydrolytic enzymes, and cell wall biogenesis in C. albicans/C. glabrata upon treating with EPTL.

The current data on anti-biofilm activity of EPTL establish its candidacy for drug development or as an adjuvant with existing antifungal formulations.

Present investigation elucidates the mode of action of Eucalyptol as antifungal agent and would stand as a candidate for management of topical fungal infection.