Inhibitory activity of thymol against the formation and viability of Candida albicans hyphae

Abstract

As the capacity of Candida albicans to produce hyphae is considered an important virulence factor in the pathogenesis of candiasis, the aim of this study was to investigate whether thymol, the major component of thyme oil, can interfere with the filamentous forms of Candida albicans and their viability. The morphological transition from yeasts to filamentous forms was investigated by analysing the morphological index (MI), which classifies the differentiated forms and blastoconidia; viability was investigated by means of fluorescence microscopy using a new SYTO-9 and propidium iodide method previously used to stain only blastoconidia. Without thymol, there was an average of 94.00 +/- 3.06% hyphal forms. After 6 h of incubation with 1x MIC (125 microg ml(-1)), 1/2x MIC and 1/4x MIC of thymol, filamentation was, respectively, 14.33 +/- 8.25%, 28.33 +/- 7.17% and 45.67 +/- 8.09% in comparison with control (all statistically significant). In the absence of thymol, viable cells accounted for an average of 93.00 +/- 4.00% whereas, after 6 h of incubation with 1x MIC, 1/2x MIC and 1/4x MIC of thymol, the presence of 54.33 +/- 1.86%, 29.00 +/- 3.61% and 23.00 +/- 2.52% of yellow-orange coloured forms indicated damaged membranes and reduced viability. Our findings show that thymol interferes with the formation and viability of hyphae. This can be attributed to the characteristics of thymol disturbing Candida cell membranes and metabolism, probably by affecting fungal cell-wall synthesising enzymes.

Study of the antifungal potential of (r)-(+)-citronellal and its association with therapeutic agents used in the treatment of vulvovaginal candidiasis

“…Therefore, these interactions may cause a greater influx of antifungal agents, resulting in the increase of the inhibition zones and thus reducing the resistances of these yeasts (Table 4) (SANCHEZET et al, 2004;BRAGA et al, 2007;ZORE et al, 2011b).…”

Footwear Protection against Fungi Using Thyme Essential Oil

“…Some essential oils have the ability to kill parasites and fungal infections, which is why they are so popular for use in fighting toenail fungus, ringworm and athlete's toenail infection. Another study reported the effectiveness of thymol in eliminating candida fungus [16].…”

Cell Viability of Candida albicans Against the Antifungal Activity of Thymol

“…The combination of SYTO-9 and propidium iodide dyes used in he present study uniformly stains tissues in green (live) or red (dead) regardless of cell morphology, since they are based on membrane integrity, being therefore better suited for viability tests in fungal biofilms. Investigating the capacity of thymol to interfere with the hyphal formation of C. albicans and its viability, a study (15) demonstrated that in the absence of thymol, about 93% of fungal cells were found viable, while after 6 h of incubation with 1x MIC, ½ x MIC and ¼ x MIC there were 54%, 29% and 23% damaged cells, respectively. The results of the present study corroborate the aforementioned study when, in absence of antifungal agent, approximately 90% of C. albicans cells were viable; however, the biofilms had their viable mass reduced in the presence of CFM thymol by an even greater proportion, exhibiting 28%, 18% and 31% living cells after 5, 15 and 30 min exposures, respectively (Table 1).…”