Evaluation of antifungal activity, mechanisms of action and toxicological profile of the synthetic amide 2-chloro-N-phenylacetamide.

Aspergillus niger causes infections such as otitis and pulmonary aspergillosis in immunocompromised individuals. Treatment involves voriconazole or amphotericin B, and due to the increase in fungal resistance, the search for new compounds with antifungal activity has intensified. In the development of new drugs, cytotoxicity and genotoxicity assays are important, as they allow predicting possible damage that a molecule can cause, and in silico studies predict the pharmacokinetic properties. The aim of this study was to verify the antifungal activity and the mechanism of action of the synthetic amide 2-chloro-N-phenylacetamide against Aspergillus niger strains and toxicity. 2-Chloro-N-phenylacetamide showed antifungal activity against different strains of Aspergillus niger with minimum inhibitory concentrations between 32 and 256 µg/mL and minimum fungicides between 64 and 1024 µg/mL. The minimum inhibitory concentration of 2-chloro-N-phenylacetamide also inhibited conidia germination. When associated with amphotericin B or voriconazole, 2-chloro-N-phenylacetamide had antagonistic effects. Interaction with ergosterol in the plasma membrane is the probable mechanism of action.2-Chloro-N-phenylacetamide has favorable physicochemical parameters, good oral bioavailability and absorption in the gastrointestinal tract, crosses the blood-brain barrier and inhibits CYP1A2. At concentrations of 50 to 500 µg/mL, it has little hemolytic effect and a protective effect for type A and O red blood cells, and in the cells of the oral mucosa it promotes little genotoxic change. It is concluded that 2-chloro-N-phenylacetamide has promising antifungal potential, favorable pharmacokinetic profile for oral administration and low cytotoxic and genotoxic potential, being a promising candidate for in vivo toxicity studies.

α-Pinene: Docking Study, Cytotoxicity, Mechanism of Action, and Anti-Biofilm Effect against Candida albicans.

Candida albicans is associated with serious infections in immunocompromised patients. Terpenes are natural-product derivatives, widely studied as antifungal alternatives. In a previous study reported by our group, the antifungal activity of α-pinene against C. albicans was verified; α-pinene presented an MIC between 128-512 µg/mL. In this study, we evaluate time-kill, a mechanism of action using in silico and in vitro tests, anti-biofilm activity against the Candida albicans, and toxicity against human cells (HaCaT). Results from the molecular-docking simulation demonstrated that thymidylate synthase (-52 kcal mol-1), and δ-14-sterol reductase (-44 kcal mol-1) presented the best interactions. Our in vitro results suggest that α-pinene's antifungal activity involves binding to ergosterol in the cellular membrane. In the time-kill assay, the antifungal activity was not time-dependent, and also inhibited biofilm formation, while rupturing up to 88% of existing biofilm. It was non-cytotoxic to human keratinocytes. Our study supports α-pinene as a candidate to treat fungal infections caused by C. albicans.

Acurácia da detecção do antígeno galactomanana no soro para o diagnóstico precoce de aspergilose pulmonar invasiva: uma revisão rápida / Accuracy of serum galactomannan antigen detection for the early diagnosis of invasive pulmonary aspergillosis: a rapid review

Tecnologia: Detecção do antígeno galactomanana no soro. Contexto: A aspergilose pulmonar invasiva (API) é uma infecção fúngica oportunista de grande risco para pacientes imunocomprometidos. A detecção do antígeno galactomanana no soro por meio de um imunoensaio (ELISA) pode ser um teste não invasivo que auxilie no diagnóstico precoce da doença nestes pacientes. Objetivo: Avaliar a acurácia da detecção do antígeno galactomana no soro para o diagnóstico precoce de aspergilose pulmonar invasiva. Métodos: Revisão rápida sistematizada sobre acurácia de diagnóstico. As bases de dados utilizadas na pesquisa foram: PUBMED, EMBASE, SCOPUS, BVS e Cochrane Library. A avaliação da qualidade metodológica dos estudos incluídos foi realizada por meio da ferramenta AMSTAR-2. Resultados: Foram selecionadas três revisões sistemáticas que atendiam aos critérios de elegibilidade com as quais foi realizada uma análise descritiva dos dados encontrados. A avaliação da qualidade metodológica demonstrou que duas das revisões sistemáticas (RS) apresentaram qualidade criticamente baixa e uma das RS apresentou qualidade alta. Conclusão: A detecção da galactomanana sérica por ELISA pode ser um teste auxiliar no diagnóstico de API, entretanto, possui várias limitações e deve ser utilizado juntamente com outros critérios diagnósticos do consenso do EORTC/MSG. Novas pesquisas devem ser fomentadas para avaliar a utilização do teste no tempo do diagnóstico e no monitoramento da API

Technology: Detection of galactomannan antigen in serum. Background: Invasive pulmonary aspergillosis (IPA) is an opportunistic fungal infection of serious risk for immunocompromised patients. Detection of galactomannan antigen in serum by immunoassay (ELISA) could be a noninvasive test that contributes to the early diagnosis of the disease in this group of patients. Objective: To evaluate the accuracy of serum galactomannan antigen detection for the early diagnosis of invasive pulmonary aspergillosis. Methods: Rapid review of diagnostic accuracy. Databases used in the search were: PUBMED, EMBASE, SCOPUS, BVS, and Cochrane Library. The methodological quality of the included studies was assessed using the AMSTAR-2 tool. Results: Three systematic reviews that satisfied the eligibility criteria were selected, and a descriptive analysis of the data found was performed. The methodological quality assessment showed that two of the systematic reviews (SR) presented critically low quality, and one of the SR presented high quality. Conclusion: Detection of serum galactomannan by ELISA may be a valuable test for diagnosing IPA; however, it has a series of limitations and should be used in conjunction with other diagnostic criteria of the EORTC/MSG consensus. Further research should be encouraged to evaluate the use of this assay, considering the time to diagnosis and IPA monitoring

Antibacterial effect of isoeugenol against Pseudomonas aeruginosa

Abatsract Pseudomonas aeruginosa is an important nosocomial pathogen and its clinical importance is mainly related to nosocomial infections. Increased rates of bacterial resistance in recent years has led WHO to publish a global priority list to guide research and discovery of new antibiotics, where P. aeruginosa is among the group of bacteria for which there is a critical level of priority for new drugs to be discovered. In this context, isoeugenol appears as an interesting alternative and the objective of this study was to investigate its action against P. aeruginosa. Isoeugenol presented significant antibacterial activity, with minimum inhibitory concentration (MIC) of 64µg/mL and minimum bactericidal concentration (MBC) of 128µg/mL, and was considered bactericidal against this species. Molecular docking revealed interactions that suggest that isoeugenol may bind to the enzyme Penicillin-Binding Protein 3 and interfere with the bacterial cell wall synthesis process. This study reinforces the antibacterial potential of this compound and emphasizes that more studies are needed in order to better investigate its mechanism of antibacterial action.

In silico and in vitro analysis of a new potential antifungal substance, 2-Bromo-N-phenylacetamide, against invasive candidiasis isolates

SUMMARY Introduction: invasive candidiasis is related to high rates of morbidity and mortality. There are few classes of drugs available for the treatment of this type of infection and the index of resistant strains is increasing. Such circumstances highlight that the search for new pharmacotherapeutic alternatives is increasingly necessary. This study investigated 2-Bromo-N-phenylacetamide, a substance whose antifungal activity has not yet been reported. Objective: to evaluate its activity against invasive candidiasis isolates, by determining the minimum inhibitory and fungicide concentrations. Methodology: molecular docking was performed to investigate the possible mechanism of action of the substance. The substance was also associated with fluconazole, to assess the viability of the combination in clinical practice. The minimum inhibitory concen trations ranged between 4 to 32 jig/mL, and it acts in a fungicidal way. Results: molec ular docking suggests that 2-Bromo-N-phenylacetamide possibly acts on the fungal plasma membrane. And the association of 2-Bromo-N-phenylacetamide with flucon azole against resistant strains showed an indifferent effect. Conclusion: further studies should be carried out to elucidate the potential of this substance, which may become a future drug candidate to treat invasive candidiasis and other fungal infections.

Introducción: la candidiasis invasiva está relacionada con altas tasas de morbilidad y mortalidad. Hay pocas clases de medicamentos disponibles para el tratamiento de este tipo de infección y el índice de cepas resistentes está aumentando. Tales circunstancias ponen de relieve que la búsqueda de nuevas alternativas farmacoterapéuticas es cada vez más necesaria. Este estudio investigó la 2-Bromo-N-fenilacetamida, una sustancia cuya actividad antifúngica aún no se ha informado. Objetivo: evaluar su actividad frente a aislados de candidiasis invasiva, mediante la determinación de las concentra ciones mínimas inhibitorias y fungicidas. Metodología: se realizó un acoplamiento molecular para investigar el posible mecanismo de acción de la sustancia. La sustancia también se asoció con fluconazol, para evaluar la viabilidad de la combinación en la práctica clínica. Las concentraciones mínimas inhibidoras oscilaron entre 4 a 32 µg/mL y actúa de forma fungicida. Resultados: el acoplamiento molecular sugiere que la 2-Bromo-N-fenilacetamida posiblemente actúa sobre la membrana plasmática de los hongos. Y la asociación de 2-Brorno-Ar-fenilacetamida con fluconazol contra cepas resistentes mostró un efecto indiferente. Conclusión: deben realizarse más estudios para dilucidar el potencial de esta sustancia, que puede convertirse en un futuro candi dato a fármaco para tratar la candidiasis invasiva y otras infecciones fúngicas.

Introdução: a candidíase invasiva está relacionada a altas taxas de morbidade e morta lidade. Existem poucas classes de medicamentos disponíveis para o tratamento desse tipo de infecção e o índice de cepas resistentes está aumentando. Tais circunstâncias evidenciam que a busca por novas alternativas farmacoterapêuticas é cada vez mais necessária. Este estudo investigou a 2-Bromo-N-fenilacetamida, uma substância cuja atividade antifúngica ainda não foi relatada. Objetivo: avaliar sua atividade contra isolados de candidíase invasiva, por meio da determinação das concentrações mínimas inibitórias e fungicidas. Metodologia: o docking molecular foi realizado para inve stigar o possível mecanismo de ação da substância. A substância também foi associada ao fluconazol, para avaliar a viabilidade da associação na prática clínica. As concen trações inibitórias mínimas variaram entre 4 a 32 µg/Ml e atuam de forma fungicida. Resultados: o docking molecular sugere que a 2-Bromo-N-fenilacetamida possivel mente atua na membrana plasmática do fungo. E a associação de 2-Bromo-N-fenilace-tamida com fluconazol contra cepas resistentes mostrou efeito indiferente. Conclusão: Novos estudos devem ser realizados para elucidar o potencial dessa substância, que pode se tornar uma futura droga candidata ao tratamento de candidíase invasiva e outras infecções fúngicas.

The impact that ß-citronellol isomers have on the biofilm formation of Candida yeasts.

Infections associated with biofilms developed by Candida spp. are becoming a great problem due to its resistance against the immune response of the host and the action of antifungal agents. Hence, finding substances that can inhibit the development of biofilms increases the likelihood that these compounds one day can become good antifungals applied in the clinic. The aim of this study was to evaluate the effect of ß-citronellol enantiomers on the biofilm formation by Candida albicans and Candida tropicalis isolated from bloodstream infections. Inhibition was evaluated by reading microplates treated with different concentrations of R-(+)-ß-citronellol, S-(-)-ß-citronellol and amphotericin B, compared to negative control, in spectrophotometer at 590 nm. All tested concentrations of ß-citronellol enantiomers inhibited the biofilm formation of Candida. However, it is still necessary to evaluate the behavior of these isomers on mature biofilms, so that they can become more viable as antifungal therapeutical agents.

Potential of 2-Chloro-N-(4-fluoro-3-nitrophenyl)acetamide Against Klebsiella pneumoniae and In Vitro Toxicity Analysis.

Klebsiella pneumoniae causes a wide range of community and nosocomial infections. The high capacity of this pathogen to acquire resistance drugs makes it necessary to develop therapeutic alternatives, discovering new antibacterial molecules. Acetamides are molecules that have several biological activities. However, there are no reports on the activity of 2-chloro-N-(4-fluoro-3-nitrophenyl)acetamide. Based on this, this study aimed to investigate the in vitro antibacterial activity of this molecule on K. pneumoniae, evaluating whether the presence of the chloro atom improves this effect. Then, analyzing its antibacterial action more thoroughly, as well as its cytotoxic and pharmacokinetic profile, in order to contribute to future studies for the viability of a new antibacterial drug. It was shown that the substance has good potential against K. pneumoniae and the chloro atom is responsible for improving this activity, stabilizing the molecule in the target enzyme at the site. The substance possibly acts on penicillin-binding protein, promoting cell lysis. The analysis of cytotoxicity and mutagenicity shows favorable results for future in vivo toxicological tests to be carried out, with the aim of investigating the potential of this molecule. In addition, the substance showed an excellent pharmacokinetic profile, indicating good parameters for oral use.

(R)-(+)-ß-Citronellol and (S)-(-)-ß-Citronellol in Combination with Amphotericin B against Candida Spp.

The enantiomers (R)-(+)-ß-citronellol and (S)-(-)-ß-citronellol are present in many medicinal plants, but little is understood about their bioactivity against Candida yeasts. This study aimed to evaluate the behavior of positive and negative enantiomers of ß-citronellol on strains of Candida albicans and C. tropicalis involved in candidemia. The minimum inhibitory concentration (MIC) and minimum fungicide concentration (MFC) were determined. The evaluation of growth kinetics, mechanism of action, and association studies with Amphotericin B (AB) using the checkerboard method was also performed. R-(+)-ß-citronellol and S-(-)-ß-citronellol presented a MIC50% of 64 µg/mL and a MFC50% of 256 µg/mL for C. albicans strains. For C. tropicalis, the isomers exhibited a MIC50% of 256 µg/mL and a MFC50% of 1024 µg/mL. In the mechanism of action assay, both substances displayed an effect on the fungal membrane but not on the fungal cell wall. Synergism and indifference were observed in the association of R-(+)-ß-citronellol and AB, while the association between S-(-)-ß-citronellol and AB displayed synergism, additivity, and indifference. In conclusion, both isomers of ß-citronellol presented a similar profile of antifungal activity. Hence, they can be contemplated in the development of new antifungal drugs providing that further research is conducted about their pharmacology and toxicity.