Objective The objective of this study was to analyze the antifungal activity of citral, selected by screening natural products, against Candida albicans isolates from subjects who use dental prostheses. Methodology Screening of essential oils, including those from Mentha piperita L. (Briq), Origanum vulgare, and Zingiber officinale L., and the phytoconstituents citral and limonene, to select an appropriate natural product. Citral, which mediated the best antifungal response, was selected for biological assays. The minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs) for citral and nystatin were determined by the microdilution method. Micromorphological analyses, time-kill curve, and modulation tests were performed. Results The MIC and MFC of citral were established as 32 μg/mL, consistent with fungicidal activity. The clinical strains were resistant to nystatin. Citral caused micromorphological alteration in the strains. In the time-kill curve, the growth of the clinical strain was reduction in growth equal to 3 log10 colony-forming units per milliliter after exposure to the MIC and MIC × 2 of citral for 2 h. Citral did not modulate the resistance of the studied strains to nystatin. Conclusion This study revealed the potential of citral as a fungicidal agent and highlighted the resistance of clinical strains of C. albicans to nystatin.

Introduction: This increase in the prevalence of drug-resistant pathogens occurs at a time when the discovery and development of new antimicrobial agents occur slowly. In this context, the objective of this study was to investigate the antifungal activity of isoeugenol, a phenylpropanoid, by in vitro and in silico assays against Penicillium citrinum strains. Material and Method: For in silico analysis, the software PASS online, Molinspiration and Osíris were used. For the determination of Minimum Inhibitory Concentration (MIC) and Minimal Fungicide Concentration (MFC) of isoeugenol and voriconazole were carried out using the broth microdilution technique. PASS online has shown that isoeugenol has the opportunity to present antiseptic, antifungal, antibacterial, antimycobacterial activities. Molinspiration showed that the phytoconstituent has good potential for oral bioavailability. Conclusion: In the analysis with the Osiris program, it was demonstrated that isoeugenol has low irritant and tumorigenic risk. The MIC of isoeugenol varied between 256 and 32 µg/mL, MIC50 of 64 µg/mL and MIC90 was 128 µg/mL. The MFC50, MFC90 and MFC of the isoeugenol for P. citrinum species were 64, 256 and 518 μg/mL, respectively. After analysis, it was verified that the isoeugenol have bactericidal effect against the strains of P. citrinum. After these results, it is important to discover the mechanism of action involved in the antifungal action of the compound, as well as in vitro and in vivo toxicity tests.

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<p>Os monoterpenos são uma classe de metabolitos secundários de plantas<strong> </strong>conhecidas por apresentar uma variedade de efeitos em diferentes sistemas biológicos. Portanto, o objetivo deste estudo foi avaliar os efeitos farmacológicos e toxicológicos dos enantiômeros (<em>R</em>)-(+)- e (<em>S</em>)-(-)-citronelal <em>in sílico</em>. Cerca de 50% das razões que levam à insuficiência no desenvolvimento de um fármaco estão associados com o perfil farmacocinético e toxicológico. Assim, a determinação do perfil farmacocinético (ADME) juntamente com a toxicidade (ADMET) são parâmetros importantes na definição de biodisponibilidade e efeitos tóxicos de uma molécula. Os softwares Pass online, Osiris e Molinspiration foram utilizados no estudo para atividades <em>in sílico</em>. Modelos <em>in sílico</em> são aplicados para a avaliação da toxicidade de compostos em ambientes metabólicos de mamíferos. Os resultados obtidos mostraram que as moléculas foram semelhantes a fármacos com 29 possíveis atividades com Pa &gt; 70% e estes monoterpenos apresentaram baixo risco de toxicidade teórica.</p>

ABSTRACT:Vulvovaginal candidiasis (VVC) is a common fungal infection that affects healthy women of all ages. At least 75% of women will develop one or more infections once during their lifetime, with 6 to 9% of those individuals developing recurrent infections. In view of this context, this study sought to evaluate the antifungal potential of the isolated (R)-(+)-citronellal [(R)-(+)-CT] and associated to therapeutic agents of clinical importance. The enantiomer was solubilized in tween 80 and dimethylsulfoxide (DMSO). Posteriorly diluted in sterile distilled water up to the concentration of 2048µg/mL. The minimum inhibitory concentration (MIC) of the product was determined by microdilution in RPMI-1640 obtaining dilutions of 1024-4µg/mL. The minimum fungicidal concentration (MFC) was determined by the Sabouraud dextrose agar (SDA) depletion technique from aliquots of 1µL of the MIC, MIC × 2 and MIC × 4. The MIC and the MFC values of (R)-(+)-CT for 90% of the C. albicans strains were 16 and 32µg/mL respectively. In the susceptibility test, C. albicans presented a high resistance to fluconazole and to itraconazole, 12 (92.30%) of the strains. However, for ketoconazole and miconazole the resistance was of 4 (30.76%) and 3 (23.07%) of the strains respectively. In the combination testing of the (R)-(+)-CT with ketoconazole and miconazole, the resistance was completely reverted. For fluconazole and itraconazole, the resistance was reverted in 9 (75%) and 7 (58.33%) of the strains respectively. The (R)-(+)-CT presented fungicide activity with MFC of MIC × 2. When in combination with ketoconazole, fluconazole, itraconazole and miconazole increased the inhibition zones of these antifungal drugs, reducing the resistance against C. albicans.

In the current context of emerging drug-resistant fungal pathogens such as Candida albicans and Candida parapsilosis, discovery of new antifungal agents is an urgent matter. This research aimed to evaluate the antifungal potential of 2-chloro-N-phenylacetamide against fluconazole-resistant clinical strains of C. albicans and C. parapsilosis. The antifungal activity of 2-chloro-N-phenylacetamide was evaluated in vitro by the determination of the minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC), inhibition of biofilm formation and its rupture, sorbitol and ergosterol assays, and association between this molecule and common antifungal drugs, amphotericin B and fluconazole. The test product inhibited all strains of C. albicans and C. parapsilosis, with a MIC ranging from 128 to 256 µg.mL-1, and a MFC of 512-1,024 µg.mL-1. It also inhibited up to 92% of biofilm formation and rupture of up to 87% of preformed biofilm. 2-chloro-N-phenylacetamide did not promote antifungal activity through binding to cellular membrane ergosterol nor it damages the fungal cell wall. Antagonism was observed when combining this substance with amphotericin B and fluconazole. The substance exhibited significant antifungal activity by inhibiting both planktonic cells and biofilm of fluconazole-resistant strains. Its combination with other antifungals should be avoided and its mechanism of action remains to be established.

Avaliação do perfil epidemiológico da tuberculose e a sua coinfecção TB-HIV nos estados da Paraíba e Rio Grande do Norte Evaluation of the epidemiological profile of tuberculosis and its TB-HIV coinfection in the states of Paraíba and Rio Grande do Norte