BackgroundLimitations of antifungal agents used in the treatment of oral candidiasis, as the development of resistant strains, are known by the scientific community. In this context, the aim of this study was to evaluate the antifungal activity of thymol against Candida albicans, Candida tropicalis and Candida krusei strains and to determine its mode of action and synergistic effect when combined with the synthetic antifungal nystatin.MethodsThe minimum inhibitory concentration (MIC) was determined using a microdilution technique, and the minimum fungicidal concentration (MFC) was determined via subculture sowing. The mode of action of thymol was established by verifying fungal growth in the presence of sorbitol or ergosterol. The fractional inhibitory concentration index (FIC) was determined using the checkerboard method.ResultsThymol presented an antifungal effect, with MICs of 39 μg/mL for C. albicans and C. krusei and 78 μg/mL for C. tropicalis. The results of the antifungal test remained unchanged in the presence of sorbitol; however, the MIC value of thymol against C. albicans increased eight times (from 39.0 to 312.5 μg/mL) in presence of exogenous ergosterol. The combination of thymol and nystatin reduced the MIC values of both products by 87.4 %, generating an FIC index of 0.25.ConclusionsThymol was found to have a fungicidal effect on Candida species and a synergistic effect when combined with nystatin.

Mammalian models have served as a basis for R&D over the past decades. Nevertheless, these models are expensive, laborious, may yield results that cannot always be translated into the human in vivo situation and, more recently, have reverberated great social and ethical dilemmas. Hence, the prospect of changes in the global scientific scenario and the Three Rs principle (Reduction, Replacement and Refinement) have encouraged the development of alternative methods to the use of mammals. Despite the efforts, suitable alternative tests are not available in all areas of biomedical research, as regulatory acceptance requires time, prior validation and robust financial and scientific investment. In this perspective, we aim to shed light on the concepts, challenges and perspectives for implementation of innovative alternative animal and non-animal methods in scientific research. The applicability and meaningfulness of invertebrate animal models, in silico analysis and reverse pharmacology are discussed, among other aspects of relevance in today's scenario. Overall, the use of alternative models, including Artemia salina (brine shrimp), Caenorhabditis elegans (roundworm), Danio rerio (zebra fish), Drosophila melanogaster (fruit fly), Galleria mellonella (greater waxmoth) and in silico modelling, increased 909% from 1990 to 2015, as compared to 154% of conventional mammals in the same period. Thus, technological and scientific advancements in the fields of toxicology and drug development seem to have diminished the need for mammalian models. Today, however, mammals still remain critically indispensable to provide - in most cases -reliable data subsidizing and validating translation into the clinical setting.

We conclude the following: (1) 18 Gy CRT per se was not an independent toxic agent for cognitive outcome; (2) HD-MTX during induction was associated with IQ decline in girls, but only when it was followed by CRT; and (3) impairment of verbal memory and coding was a consistent finding that was independent of CRT, which implicates some component of chemotherapy, possibly prednisone, as a CNS toxin.

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This study analyzed the antifungal activity of phytoconstituents from linalool on Candida spp. strains, in vitro, isolated from patients with clinical diagnoses of oral candidiasis associated with the use of a dental prosthesis. Biological samples were collected from 12 patients using complete dentures or removable partial dentures and who presented mucous with diffuse erythematous or stippled features, indicating a clinical diagnosis of candidiasis. To identify fungal colonies of the genus Candida, samples were plated onto CHROMagar Candida  . The antifungal activity of linalool, a monoterpene unsaturated constituent of basil oil, was performed using the broth microdilution technique. Then, the minimum inhibitory concentration (MIC), the two subsequent stronger concentrations and the positive controls were subcultured on Sabouraud Dextrose Agar plates to determine the minimum fungicidal concentration (MFC). The experiments were performed in triplicate and nystatin was used as a positive control in all tests. Diagnoses of oral candidiasis were verified in eight patients (66.6%) and the most prevalent fungal species was Candida albicans (37.5%), followed by Candida krusei (25.0%); and Candida tropicalis (4.2%). The best antifungal activity of linalool was observed on Candida tropicalis (MIC = 500 mg/mL), followed by Candida albicans (MIC = 1.000 mg/mL), and Candida krusei (MIC = 2.000 mg/mL).Under the study conditions and based on the results obtained, it can be concluded that the Candida strains tested were susceptible to linalool.Keywords: candidiasis, linalool, phytotherapy. Atividade antifúngica do linalol em casos de Candida spp. isolados de indivíduos com candidíase oral ResumoEste estudo analisou a atividade antifúngica do fitoconstituinte linalol em cepas de Candida ssp, in vitro, isolados de pacientes com o diagnóstico clínico de candidíase oral associado ao uso de prótese dentária. As amostras biológicas foram coletadas de 12 pacientes portadores de próteses totais ou próteses parciais removíveis e que apresentavam características de mucosa eritematosa difusa ou pontilhadas, indicando um diagnóstico clínico de candidíase. Para identificar colônias de fungos do gênero Candida, as amostras foram semeadas em CHROMagar Candida  . A atividade antifúngica do linalol, um componente insaturado monoterpene de óleo de manjericão, foi realizada através da técnica de microdiluição em caldo. Em seguida, a concentração inibitória mínima (MIC), as duas concentrações consecutivas mais fortes e os controles positivos foram subcultivados em placas de Agar Sabouraud Dextrose para determinar a concentração fungicida mínima (MFC). Os experimentos foram realizados em triplicata e a nistatina foi usada como controle positivo em todos os testes. O diagnóstico de candidíase oral foi comprovado em oito pacientes (66,6%) e as espécies de fungos mais prevalentes foram Candida albicans (37,5%), seguido por Candida krusei (25,0%); e Candida tropicalis (4,2%). A melhor atividade antifúngica do linalol foi observada em Candi...