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Antifungal Activity of Natural Compounds vs. Candida spp.: A Mixture of Cinnamaldehyde and Eugenol Shows Promising In Vitro Results

Candida spp. are commensal organisms of the skin, mucous membranes, gastrointestinal tract, blood, and vagina of animals and humans. In recent decades, the incidence of human fungal infections has increased, with Candida spp. (mainly C. albicans) infections being the most frequent, and the treatment...

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Autores principales: Saracino, Ilaria Maria, Foschi, Claudio, Pavoni, Matteo, Spigarelli, Renato, Valerii, Maria Chiara, Spisni, Enzo
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8773119/
https://www.ncbi.nlm.nih.gov/pubmed/35052950
http://dx.doi.org/10.3390/antibiotics11010073
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author Saracino, Ilaria Maria
Foschi, Claudio
Pavoni, Matteo
Spigarelli, Renato
Valerii, Maria Chiara
Spisni, Enzo
author_facet Saracino, Ilaria Maria
Foschi, Claudio
Pavoni, Matteo
Spigarelli, Renato
Valerii, Maria Chiara
Spisni, Enzo
author_sort Saracino, Ilaria Maria
collection PubMed
description Candida spp. are commensal organisms of the skin, mucous membranes, gastrointestinal tract, blood, and vagina of animals and humans. In recent decades, the incidence of human fungal infections has increased, with Candida spp. (mainly C. albicans) infections being the most frequent, and the treatment of fungal infections is still a clinical challenge. Colonization of the human gastrointestinal tract by Candida spp. is significant because infections (e.g., candidemia and vulvovaginal candidiasis) frequently arise from commensal microorganisms. The aim of this study was to test in vitro the antifungal activity and the eventual synergistic effect of five pure components of essential oils: cinnamaldehyde, α-pinene, limonene, eucalyptol, and eugenol. These compounds were tested on 18 Candida strains (15 C. albicans, 2 C. glabrata, and 1 C. lusitaniae) derived from a culture collection of vaginal clinical strains. Methods: Fungistatic activity was evaluated using the disk diffusion method. For fungicidal activity, microdilution and time–kill curve protocols were set up. The checkerboard method was chosen to evaluate a possible synergistic effect of these compounds when mixed. Results: Cinnamaldehyde and eugenol gave the best results, inhibiting all the Candida strains and showing a highly additive effect (FICI 0.625). The cinnamaldehyde inhibition zone (IZ), MIC, and MFC means were 69 mm, 50.05 mg/L, and 109.26 mg/L respectively. Cinnamaldehyde led to the total loss of viable Candida cells within 4 h. Eugenol IZ, MIC, and MFC means were 35.2 mm, 455.42 mg/L, and 690.09 mg/L, respectively. Eugenol led to the total loss of viable fungal cells within 1 h. Treatment with α-pinene inhibited 88.9% of Candida strains, with an IZ mean of 21.2 mm, a MIC mean of 195.41 mg/L, and a MFC mean of 251.27 mg/L; this compound led to the total loss of viable fungal cells only after 24 h. Limonene inhibited only 33.3% of the tested strains and eucalyptol did not produce an inhibition halo, so these compounds were not tested further. Conclusions: These characteristics, together with the well-known safety of cinnamaldehyde and eugenol for human use, make these two natural compounds the perfect candidates for the treatment of candidiasis. This was a pilot study, the purpose of which was to evaluate the best composition of a mixture to be used against intestinal and vulvovaginal candidiasis; in vivo studies are needed to confirm these very encouraging results.
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spelling pubmed-87731192022-01-21 Antifungal Activity of Natural Compounds vs. Candida spp.: A Mixture of Cinnamaldehyde and Eugenol Shows Promising In Vitro Results Saracino, Ilaria Maria Foschi, Claudio Pavoni, Matteo Spigarelli, Renato Valerii, Maria Chiara Spisni, Enzo Antibiotics (Basel) Article Candida spp. are commensal organisms of the skin, mucous membranes, gastrointestinal tract, blood, and vagina of animals and humans. In recent decades, the incidence of human fungal infections has increased, with Candida spp. (mainly C. albicans) infections being the most frequent, and the treatment of fungal infections is still a clinical challenge. Colonization of the human gastrointestinal tract by Candida spp. is significant because infections (e.g., candidemia and vulvovaginal candidiasis) frequently arise from commensal microorganisms. The aim of this study was to test in vitro the antifungal activity and the eventual synergistic effect of five pure components of essential oils: cinnamaldehyde, α-pinene, limonene, eucalyptol, and eugenol. These compounds were tested on 18 Candida strains (15 C. albicans, 2 C. glabrata, and 1 C. lusitaniae) derived from a culture collection of vaginal clinical strains. Methods: Fungistatic activity was evaluated using the disk diffusion method. For fungicidal activity, microdilution and time–kill curve protocols were set up. The checkerboard method was chosen to evaluate a possible synergistic effect of these compounds when mixed. Results: Cinnamaldehyde and eugenol gave the best results, inhibiting all the Candida strains and showing a highly additive effect (FICI 0.625). The cinnamaldehyde inhibition zone (IZ), MIC, and MFC means were 69 mm, 50.05 mg/L, and 109.26 mg/L respectively. Cinnamaldehyde led to the total loss of viable Candida cells within 4 h. Eugenol IZ, MIC, and MFC means were 35.2 mm, 455.42 mg/L, and 690.09 mg/L, respectively. Eugenol led to the total loss of viable fungal cells within 1 h. Treatment with α-pinene inhibited 88.9% of Candida strains, with an IZ mean of 21.2 mm, a MIC mean of 195.41 mg/L, and a MFC mean of 251.27 mg/L; this compound led to the total loss of viable fungal cells only after 24 h. Limonene inhibited only 33.3% of the tested strains and eucalyptol did not produce an inhibition halo, so these compounds were not tested further. Conclusions: These characteristics, together with the well-known safety of cinnamaldehyde and eugenol for human use, make these two natural compounds the perfect candidates for the treatment of candidiasis. This was a pilot study, the purpose of which was to evaluate the best composition of a mixture to be used against intestinal and vulvovaginal candidiasis; in vivo studies are needed to confirm these very encouraging results. MDPI 2022-01-08 /pmc/articles/PMC8773119/ /pubmed/35052950 http://dx.doi.org/10.3390/antibiotics11010073 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Saracino, Ilaria Maria
Foschi, Claudio
Pavoni, Matteo
Spigarelli, Renato
Valerii, Maria Chiara
Spisni, Enzo
Antifungal Activity of Natural Compounds vs. Candida spp.: A Mixture of Cinnamaldehyde and Eugenol Shows Promising In Vitro Results
title Antifungal Activity of Natural Compounds vs. Candida spp.: A Mixture of Cinnamaldehyde and Eugenol Shows Promising In Vitro Results
title_full Antifungal Activity of Natural Compounds vs. Candida spp.: A Mixture of Cinnamaldehyde and Eugenol Shows Promising In Vitro Results
title_fullStr Antifungal Activity of Natural Compounds vs. Candida spp.: A Mixture of Cinnamaldehyde and Eugenol Shows Promising In Vitro Results
title_full_unstemmed Antifungal Activity of Natural Compounds vs. Candida spp.: A Mixture of Cinnamaldehyde and Eugenol Shows Promising In Vitro Results
title_short Antifungal Activity of Natural Compounds vs. Candida spp.: A Mixture of Cinnamaldehyde and Eugenol Shows Promising In Vitro Results
title_sort antifungal activity of natural compounds vs. candida spp.: a mixture of cinnamaldehyde and eugenol shows promising in vitro results
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8773119/
https://www.ncbi.nlm.nih.gov/pubmed/35052950
http://dx.doi.org/10.3390/antibiotics11010073
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