Antibiofilm and Antihyphal Activities of Cedar Leaf Essential Oil, Camphor, and Fenchone Derivatives against Candida albicans.

Ranjith Kumar Manoharan,Jintae Lee,Jin-Hyung Lee

doi:10.3389/fmicb.2017.01476

Abstract

Candida albicans can form biofilms composed of yeast, hyphal, and pseudohyphal elements, and C. albicans cells in the hyphal stage could be a virulence factor. The present study describes the chemical composition, antibiofilm, and antihyphal activities of cedar leaf essential oil (CLEO), which was found to possess remarkable antibiofilm activity against C. albicans but not to affect its planktonic cell growth. Nineteen components were identified in CLEO by gas chromatography/mass spectrometry, and phenolics were the main constituents. Of these, camphor, fenchone, fenchyl alcohol, α-thujone, and borneol significantly reduced C. albicans biofilm formation. Notably, treatments with CLEO, camphor, or fenchyl alcohol at 0.01% clearly inhibited hyphal formation, and this inhibition appeared to be largely responsible for their antibiofilm effects. Transcriptomic analyses indicated that camphor and fenchyl alcohol downregulated some hypha-specific and biofilm related genes (ECE1, ECE2, RBT1, and EED1). Furthermore, camphor and fenchyl alcohol reduced C. albicans virulence in a Caenorhabditis elegans nematode model. These results demonstrate CLEO, camphor, and fenchyl alcohol might be useful for controlling C. albicans infections.

Highlights

Candidiasis is an opportunistic infection, which affects skin and mucous membranes in a large number of individuals
cedar leaf essential oil (CLEO) and cedar wood oil at 0.01% inhibited C. albicans biofilm formation by more than 85% without affecting planktonic cell growth
CLEO was found to dose-dependently inhibit C. albicans biofilm formation (Figure 1), to reduce biofilm formation by 87% at a concentration of 0.01% and completed inhibited biofilm formation at 0.1% (Figure 1)

Summary

Introduction

Candidiasis is an opportunistic infection, which affects skin and mucous membranes in a large number of individuals. The initial stage of infection is adherence, where yeast cells attach to surfaces and form a monolayer, this is followed by morphological transition involving the elongation of hyphae (Silva-Dias et al, 2015; Carradori et al, 2016), which invade tissues and cause infectious diseases (Fox et al, 2015). Biofilms attach to surfaces or interfaces, and are embedded in a matrix of extracellular polymeric substances, and cause various infections (Costerton et al, 1999). Biofilm formation on medical devices and biomaterials, such as catheters, and heart valves, and cause infections, which are often chronic, with high morbidity and mortality rates (Uppuluri et al, 2010; Seddiki et al, 2013). Biofilms are inherently difficult to eradicate in cases of implant-associated infections, and new antifungal agents are required to prevent biofilm formation.

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