In vitro antifungal activity of Cinnamomum zeylanicum bark and leaf essential oils against Candida albicans and Candida auris

Hoang N H Tran,Emmanuel C Adukwu,Lee Graham

doi:10.1007/s00253-020-10829-z

Hoang N H Tran, Emmanuel C Adukwu + Show 1 more

Open Access

https://doi.org/10.1007/s00253-020-10829-z

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Abstract

Candida infections are a significant source of patient morbidity and mortality. Candida albicans is the most common pathogen causing Candida infections. Candida auris is a newly described pathogen that is associated with multi-drug-resistant candidiasis and candidaemia in humans. The antifungal effects of various essential oils and plant compounds have been demonstrated against human pathogenic fungi. In this study, the effect of cinnamon leaf and bark essential oils (CEOs) was determined against both C. albicans and C. auris. The disc diffusion (direct and vapour) and broth microdilution method was used to determine antifungal activity of the EOs against selected strains (C. albicans ATCC 10231, C. albicans ATCC 2091 and C. auris NCPF 8971) whilst the mode of action and haemolysin activity of the CEOs were determined using electron microscopy and light microscopy. Direct and vapour diffusion assays showed greater inhibitory activity of bark CEO in comparison with leaf CEO. The minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs) of bark CEO for all tested strains was below 0.03% (v/v), which was lower than the MICs of the leaf CEO (0.06–0.13%, v/v) dependent on the strain and the MFCs at 0.25% (v/v). In the morphological interference assays, damage to the cell membrane was observed and both CEOs inhibited hyphae formation. The haemolysin production assay showed that CEOs can reduce the haemolytic activity in the tested C. albicans and C. auris strains. At low concentrations, CEOs have potent antifungal and antihaemolytic activities in vitro against C. albicans and C. auris.Key points• Essential oils from Cinnamomum zeylanicum Blume bark and leaf (CBEO and CLEO) demonstrated fungicidal properties at very low concentrations.• The antifungal activity of CBEO was greater than that of CLEO consistent with other recent published literature.• The mode of action of CBEO and CLEO was damage to the membrane of C. albicans and C. auris.• Both CBEO and CLEO inhibited the formation of hyphae and reduced haemolysin production in C. albicans and C. auris.Graphical abstract

Highlights

Fungal infections are common diseases of the natural world
The inhibitory action of CLEO against the Candida spp. at low concentrations between 0.06 and 0.13% (v/v) was effective at inhibiting the growth of C. albicans and C. auris strains; fungicidal activity of CLEO was observed at 0.25% (v/v)
The mechanism of action of CBEO and CLEO on C. albicans and C. auris was determined by cellular content leakage assay and scanning electron microscopy (SEM) morphological analysis following treatment with both CBEO and CLEO

Summary

Introduction

Fungal infections occur when the immune system is unable to deal with a considerable amount of trespassing fungi or yeast invading an area of the body. There are several classes of fungal infections, and of these, Candida infections are regarded as a significant cause of patient morbidity and mortality (Sardi et al 2013). Candida infections are caused by commensal fungi Candida spp., especially Candida albicans, which resides on the skin, mucosa and gastrointestinal tract of 30 to 50% of healthy adults at any given time, with everyone being colonized at some point in their lifetime (Brown and Netea 2007). Candida auris is a newly described opportunistic. C. auris is known to be resistant to several classes of antifungal drugs including the first-line antifungal, fluconazole, and exhibits variable susceptibility to other azoles, amphotericin B, and echinocandins (Chowdhary et al 2016). C. auris has a potential for person-toperson transmission, challenging clinicians and infection control teams (Ben-Ami et al 2017)

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