Avaliação in vitro do potencial antifúngico de sais imidazólicos frente à Candida albicans / In vitro evaluation of antifungal potential of imidazolium salts against Candida albicans

Objetivo: O objetivo deste estudo foi avaliar o potencial antifúngico de um conjunto de sais imidazólicos (SI) frente a Candida albicans. Materiais e métodos: A avaliação an-tifúngica dos SI foi realizada por meio do teste de difusão em ágar, utilizando uma cepa de Candida albicans (ATCC 90028). Cinco diferentes SI foram sintetizados e testados no presente estudo: brometo de 1,8-bis(metilimidazólio-1-il) octano (MImC8MImBr2), metanossulfonato de 1,12-bis(-metilimidazólio-1-il) dodecano (MImC12MIm(MeS)2), clo-reto de 1-n-hexadecil-2,3-dimetilimidazólio (C16DMImCl), metanossulfonato de 1,10-bis(metilimidazólio-1-il) decano (MImC10MIm(MeS)2) e brometo de 1,10-bis(metilimidazólio--1-il) decano (MImC10MImBr2). O cloreto de cetilpiridíneo (C16PyrCl) foi utilizado como composto de referência e as soluções de digluconato de clorexidina (C34H54Cl2N10O14) e salina (NaCl 0,9%) foram utilizadas como controles po-sitivo e negativo, respectivamente. Resultados: Dentre os SI testados, MImC12MIm(MeS)2, MImC10MIm(MeS)2 e MImC10MImBr2 apresentaram os seguintes valores para os halos de inibição formados: 28,00 mm, 20,50 mm e 18,75 mm, respectivamente. Esses valores foram similares ou superiores inclusive aos encontrados para o controle positivo (14,87 mm) e o composto de referência (0 mm). Discussão: Os SI podem apresentar uma alternativa promissora às terapias com antifúngicos convencionais, concordando com estudos prévios. Entretanto, mais estudos in vitro e in vivosão necessários para avaliar o potencial antifúngico destes compostos frente a biofilmes multiespécies de C. albicans. Conclusão: Baseado nestes resultados, três dos SI testados apresentam atividade antifúngica in vitro promissora frente à Candida albicans.

Aim: This study aims to evaluate the antifungal potential of imidazolium salts (IS) against Candida albicans. Material and methods: Antifungal evaluation of the IS was perfor-med using the disk diffusion test, using a strain of Candida albicans (ATCC 90028). Five different IS were synthesized and tested in the present study: 1,8-bis(methylimidazolium-1-yl) octane bromide (MImC8MImBr2), 1,12-bis(methylimida-zolium-1-yl) dodecane methanesulfonate (MImC12MIm(-MeS)2), 1-n-hexadecyl-2,3-dimethylimidazolium chloride (C16DMImCl), 1,10-bis(methylimidazolium-1-yl) decane methanesulfonate (MImC10MIm(MeS)2) e 1,10-bis(me-thylimidazolium-1-yl) decane bromide (MImC10MImBr2). Cetylpyridinium chloride (C16PyrCl) was used as a reference substance. Chlorhexidine (C34H54Cl2N10O14) and saline (NaCl 0,9%) solutions were positive and negative controls, respectively. Results: Among the tested IS, MImC12MIm(-MeS)2, MImC10MIm(MeS)2 and MImC10MImBr2 showed the following values for inhibition halos: 28,00 mm, 20,50 mm and 18,75 mm, respectively. These values were similar or superior than those found for the positive control (14.87 mm) and reference (0 mm) substances. Discussion: IS can be a promising alternative to antifungal conventional therapies, as exemplified in previous studies. However, further in vitro and in vivo studies are needed to assess the antifungal potential of these compounds against Candida--mixed biofilms.Conclusion: Based on these results, three IS, tested in this study, have in vitro promissing antifungal potential against Candida albicans.

Is the emergence of fungal resistance to medical triazoles related to their use in the agroecosystems? A mini review

Abstract Triazole fungicides are used broadly for the control of infectious diseases of both humans and plants. The surge in resistance to triazoles among pathogenic populations is an emergent issue both in agriculture and medicine. The non-rational use of fungicides with site-specific modes of action, such as the triazoles, may increase the risk of antifungal resistance development. In the medical field, the surge of resistant fungal isolates has been related to the intensive and recurrent therapeutic use of a limited number of triazoles for the treatment and prophylaxis of many mycoses. Similarities in the mode of action of triazole fungicides used in these two fields may lead to cross-resistance, thus expanding the spectrum of resistance to multiple fungicides and contributing to the perpetuation of resistant strains in the environment. The emergence of fungicide-resistant isolates of human pathogens has been related to the exposure to fungicides used in agroecosystems. Examples include species of cosmopolitan occurrence, such as Fusarium and Aspergillus, which cause diseases in both plants and humans. This review summarizes the information about the most important triazole fungicides that are largely used in human clinical therapy and agriculture. We aim to discuss the issues related to fungicide resistance and the recommended strategies for preventing the emergence of triazole-resistant fungal populations capable of spreading across environments.

In vitro ZnCl2 cytotoxicity and genotoxicity in human leukocytes: Zero-order kinetic cellular zinc influx / Citotoxicidade e genotoxicidade do ZnCl2 em leucócitos humanos in vitro: influx cellular de zinco com cinética de ordem zero

Zinc (Zn) is an essential trace element for cellular viability, but concentrations above physiologic level may lead to cellular damage. The purpose of the present study was to evaluate the in vitro ZnCl2 genotoxicity and cytotoxicity in human leukocyte cells. This was assessed in an unprecedented way that correlated the level of intracellular Zn after cell exposition with the cellular damage. The exposure to increased Zn concentrations (2.5-20 µg mL-1), showed significantly reduced cellular leukocyte viability. However, significant DNA damages were observed only when the Zn exposure concentrations were from 10-20 µg mL-1. The Zn intracellular levels found in leukocytes was from 72.25-268.9 ρ g cell-1, starting to induce cytotoxicity and genotoxicity at concentrations of 95.68 and 126.2 ρg cell-1, respectively. The relationship between the exposure concentration and intracellular levels of Zn suggests that the influx of Zn, in the form of ZnCl2, occurs in human leukocytes under zero-order kinetics.

O Zinco (Zn) é um elemento traço essencial para a viabilidade celular, mas em concentrações acima dos níveis fisiológicos pode conduzir a danos celulares. A proposta do presente estudo foi avaliar a citotoxicidade e genotoxicidade do ZnCl2 em leucócitos humanos in vitro. De maneira sem precedentes, foi acessado o nível de Zn intracelular após exposição e relacionado com o nível de dano celular. A exposição a crescentes concentrações de Zn (2,5-20 µg mL-1), mostraram significante redução da viabilidade celular dos leucócitos. Entretanto, danos significativos ao DNA foram encontrados somente a partir das concentrações de exposição ao Zn de 10-20 µg mL-1. Os níveis intracelulares de Zn encontrados nos leucócitos foram de 72,25-268,9 ρg célula-1, começando a induzir citotoxicidade e genotoxicidade nas concentrações de 95,68 and 126,2 ρg célula-1, respectivamente. A relação entre a concentração de exposição e os níveis intracelulares de Zn sugerem que o influxo de Zn, sob a forma de ZnCl2, ocorre em cinética de ordem zero em leucócitos humanos.