O potencial antimicrobiano do carveol: uma revisão integrativa

Objetivo: realizar uma revisão bibliográfica sobre o potencial antimicrobiano do carveol. É uma revisão integrativa entre os anos de 2010-2020 nas bases de dados BVS, PubMed, SciELO, ScienceDirect e Web of Science. Metodologia: dos 2753 artigos recuperados nas bases de dados, apenas 5 foram selecionados para compor os resultados, sendo os gêneros mais estudados Candida, Staphylococcus e Escherichia. A técnica de microdiluição em caldo foi a metodologia mais utilizada para determinar sua ação. Em termos de MIC, para a maioria das espécies, foram excelentes. Em relação ao teste Time-kill, o carveol teve um excelente desempenho na concentração de 4 x MIC, que mostrou uma redução de UFC de 6 log em 2 horas. Não foram encontrados na literatura estudos sobre a utilização do método Checkboard. Além disso, este composto apresentou boa atividade antibiofilme contra bactérias Staphylococcus aureus. Resultados: o possível mecanismo de ação da atividade antimicrobiana do carveol ocorre por meio dos graves danos causados às membranas citoplasmáticas, o que favorecerá a lise celular. Dessa forma, existem poucos estudos na coleção científica disponível que abordem o assunto, sendo necessária a realização de mais estudos in vitro e in vivo para melhor elucidar sua ação.

SUMMARY Aim: to carry out a bibliographic review on the antimicrobial potential of carveol. It is an integrative review between the years 2010-2020 in the BVS, PubMed, SciELO, Science-Direct and Web of Science databases. Methodology: of the 2753 articles retrieved from the databases, only 5 were selected to compose the results, the most studied genera being Candida, Staphylococcus and Escherichia. The broth microdilution technique was the most widely used methodology to determine its action. In terms of MIC, for most species, they were excellent. Regarding the Time-kill test, carveol had an excellent performance at a concentration of 4 x MIC, which showed a reduction of CFU by 6 log in 2 hours. No studies have been found in the literature on the use of the Checkboard method. Further-more, this compound had good antibiofilm activity against Staphylococcus aureus bacteria. Results: the possible mechanism of action of the antimicrobial activity of carveol occurs through the severe damage caused to the cytoplasmic membranes, which will favor cell lysis. Thus, there are few studies in the available scientific collection that address the subject, so it is necessary to carry out more in vitro and in vivo studies to better elucidate its action.

Objetivo: realizar una revisión bibliográfica sobre el potencial antimicrobiano del carveol. Se trata de una revisión integradora entre los años 2010-2020 en las bases de datos de BVS, PubMed, SciELO, ScienceDirect y Web of Science. Metodología: de los 2753 artículos recuperados de las bases de datos, solo se seleccionaron 5 para componer los resultados, siendo los géneros más estudiados Candida, Staphylococcus y Escherichia. La técnica de microdilución en caldo fue la metodología más utilizada para determinar su acción. En cuanto a CIM, para la mayoría de las especies, fueron excelentes. En cuanto al ensayo Time-kill, el carveol tuvo un excelente desempeño a una concentración de 4 x MIC, que mostró una reducción de UFC en 6 log en 2 horas. No se ha encontrado ningún estudio en la literatura sobre el uso del método Checkboard. Además, este compuesto tenía una buena actividad antibiofilm contra la bacteria Staphylococcus aureus. Resultados: el posible mecanismo de acción de la actividad antimicrobiana del carveol se produce a través del severo daño causado en las membranas citoplasmáticas, lo que favorecerá la lisis celular. Así, son pocos los estudios en la colección científica disponible que abordan el tema, por lo que es necesario realizar más estudios in vitro e in vivo para dilucidar mejor su acción.

The prevalence of dermatophytoses in Brazil: a systematic review.

Dermatophytosis is a common cutaneous mycosis worldwide whose prevalence in Brazil is still unknown. This systematic review has estimated the burden of dermatophytoses from updated literature data reported in the general Brazilian population. We used the following databases: Web of Science, Medline/PubMed, Embase, The Cochrane Library and Scopus for studies published between 2011 and 2020. Original articles with an emphasis on prevalence data for dermatophytosis in the Brazilian population, and diagnosed by culture exam or molecular biology were eligible. We also assessed the methodological quality of the studies. A total of 24 articles met the inclusion criteria and were reviewed. The occurrence of dermatophytoses found in the studies ranged from 4-88.50 %. The pooled prevalence of dermatophytosis for the population studies was 25 % (95 % CI: 24.7-25.3 %). The size of the samples used in the studies ranged from 45 to 36 446 participants, and ages ranged up to 98 years old. The populations studied involved mostly women. The presence of tinea unguium (toenail and fingernail) and tinea pedis were the most frequent dermatophytosis, and we observed a predominance of Trichophyton rubrum, T. interdigitale and T. mentagrophytes. The studies were primarily conducted in patient groups with suspected mycoses and were not entirely representative of the general population. Yet we believe that in the future, more collaborative strategies would improve both diagnostic capacity and epidemiological methodologies, associating the prevalence of dermatophytosis with social and environmental risk factors. This review helps to better understand future epidemiological trends in Brazil and the world.

Efeito Inibitório De Monoterpenos Frente A Klebsiella Pneumoniae Produtoras de ESBL / The Inhibitory Effect of Monoterpenes against ESBL-Producing Klebsiella pneumoniae

Introdução: Klebsiella pneumoniae é um bacilo Gram negativo membro da família Enterobacteriaceae, em que seus principais sítios de infecção se encontram no trato respiratório e urinário. Devido ao crescimento desenfreado da automedicação, vários microrganismos vem desenvolvendo mecanismos de resistência com maior frequência, desta forma tornando o tratamento cada vez difícil, sendo necessária a pesquisa de novas alternativas terapêuticas mais eficientes. Diversos produtos naturais têm sido estudados, a exemplo dos óleos essências e dos monoterpenos que vem apresentando ação bastante promissora frente aos microrganismos. Objetivo: Nessa perspectiva, este trabalho teve como objetivo avaliar a ação antibacteriana dos fitoconstituintes citral, citronelal e citronelol contra as cepas de K. pneumoniae produtora de betalactamase de amplo espectro (ESBL) e determinar a concentração inibitória mínima (CIM) destes monoterpenos. Materiais e Métodos: Foi realizada a técnica de microdiluição seriada a uma razão de dois, nas concentrações de 2048, 1024, 512, 256, 128, 64 a 32 µg/ mL , utilizando como meio de cultura o caldo Mueller Hinton, reservando a última coluna para o controle do crescimento microbiano, testando também a esterilidade do meio de cultura. Os experimentos foram realizados em triplicata e incubados na estufa a uma temperatura de 37 CÚ ± 2 CÚ, por um período de 24 horas, tendo como avaliação dos ensaios o método visual. Resultados: Através dos experimentos realizados, notouse que os fitoconstituintes citral, citronelal e citronelol não inibiram o crescimento das cepas de K. pneumonia nas condições e concentrações testadas. Conclusão: Os monoterpenos não apresentaram atividade antibacteriana contras cepas testadas. (AU)

Introduction: Klebsiella pneumoniae is a Gram-negative bacillus of the Enterobacteriaceae family which may infect primarily the respiratory and urinary tracts. Due to the uncontrolled growth of self-medication, various microorganisms have been developing resistance mechanisms with a greater frequency, thus making infections increasingly difficult to treat. Further research is then required to develop new, more effective treatment options. Several natural products have been studied, such as essential oils and monoterpenes, which have shown promising activity against selected microorganisms. Objective: This study aimed to evaluate the antibacterial activity of the phytochemicals citral, citronellal and citronellol against K. pneumoniae strains producing extended-spectrum beta-lactamases (ESBL), and to determine the minimum inhibitory concentration (MIC) of these monoterpenes. Material and Methods: A serial microdilution technique was performed to test the samples at concentrations of 2048, 1024, 512, 256, 128, 64 and 32 ìg/ mL. Mueller Hinton broth was employed as the culture medium, and the last column was used for the control of microbial growth and medium sterility. The experiments were carried out in triplicate and incubated at 37 CÚ ± 2 CÚ for 24 hours, followed by visual reading. Results: The phytochemicals citral, citronellal and citronellol did not inhibit the growth of K. pneumonia strains under the conditions and concentrations tested. Conclusion: The monoterpenes presented herein showed no antibacterial activity against the tested strains.(AU)

Investigation of the antifungal activity of carvacrol against strains of Cryptococcus neoformans.

BACKGROUND: Cryptococcus neoformans is the etiologic agent of opportunistic systemic fungal infection cryptococcosis, which affects individuals with compromised immune systems. Thus, natural products research has become important, since monoterpenes such as carvacrol, a promising molecule in the search antifungal agents, have shown significant biological activity. OBJECTIVE: The study aimed to investigate the antifungal activity and mode of action of carvacrol against strains of C. neoformans. METHODS: The minimum inhibitory concentration (MIC) was determined by microdilution method. Minimum fungicidal concentration (MFC) was performed by seeding technique on solid media. Studying the mode of action was performed using broth microdilution. RESULTS: The MIC ranged from 25 to 81 µg/mL and the MFC ranged from 25 to 102 µg/mL. Carvacrol bonded to exogenous ergosterol and cholesterol. DISCUSSION: The results suggest that carvacrol has antifungal activity against C. neoformans and its mode of action is related to fungal membrane instability. CONCLUSIONS: The phytoconstituent carvacrol may eventually become a drug; however, further studies are needed to elucidate its mechanism.

Antifungal activity of geraniol and citronellol, two monoterpenes alcohols, against Trichophyton rubrum involves inhibition of ergosterol biosynthesis.

CONTEXT: Trichophyton rubrum is the most common fungus causing chronic dermatophytosis in humans. Antifungal activity of promising agents is of great interest. Geraniol and citronellol are monoterpenes with antimicrobial properties. OBJECTIVE: This study aimed to investigate the inhibitory effects and possible mechanism of antifungal activity of geraniol and citronellol against strains of T. rubrum. MATERIALS AND METHODS: The minimum inhibitory concentration (MIC) of each drug against 14 strains was determined by broth microdilution. The effects of the drugs on dry mycelial weight, conidial germination, infectivity on human nail fragments, and morphogenesis of T. rubrum were analyzed. The effects on the cell wall (test with sorbitol) and cell membrane (release of intracellular material and ergosterol biosynthesis) were investigated. RESULTS: MIC values of geraniol ranged between 16 and 256 µg/mL while citronellol showed MIC values from 8 to 1024 µg/mL. The drugs (MIC and 2 × MIC) inhibited the mycelial growth, conidia germination, and fungal growth on nail fragments. The drugs (half of MIC) induced the formation of wide, short, and crooked hyphae in T. rubrum morphology. With sorbitol, geraniol MIC was increased by 64-fold and citronellol by 32-fold. The drugs caused leakage of intracellular material and inhibited ergosterol biosynthesis. DISCUSSION: The results suggest that the drugs damage cell wall and cell membrane of T. rubrum through a mechanism that seems to involve the inhibition of the ergosterol biosynthesis. CONCLUSION: This study confirms that geraniol and citronellol can be regarded as potential drugs for controlling T. rubrum growth, with great potential against agents of dermatophytosis.

Anti-Candida albicans effectiveness of citral and investigation of mode of action.

CONTEXT: Candidiasis is a mycosis caused by Candida species, which is of clinical importance due to the increase in resistant yeasts. Candida infection has been a serious health problem due to the inappropriate use of antibiotics. Therefore, it is necessary to study molecules with an antifungal action. Citral is a monoterpene with known pharmacological properties, including antimicrobial action. OBJECTIVE: The aim of this work was to determine the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of citral and the probable mode of action. MATERIALS AND METHODS: The MIC of citral was determined by the broth microdilution method using Sabouraud dextrose medium. Additionally, the interference of citral in cell wall (sorbitol assay) and the binding of citral to ergosterol and cholesterol were studied, carried out by broth microdilution method. RESULTS: The MIC and MFC of citral were 512 and 1024 µg/mL, respectively. The MIC of amphotericin B was 1 µg/mL. The mechanism of action did not involve either the cell wall or ergosterol. However, the presence of cholesterol increased the MIC of citral to 1024 µg/mL, indicating there is some interaction between citral and cholesterol. Amphotericin B was used as the positive control, and it showed a high MIC in the presence of ergosterol (32 µg/mL), while in the presence of cholesterol MIC increased to 4 µg/mL. CONCLUSION: Citral inhibits the growth of C. albicans. The probable mechanism of action did not involve the cell wall or ergosterol. Citral is able to interact with cholesterol. More studies are necessary to describe their effects completely.

Antifungal activity of Thymus vulgaris L. essential oil and its constituent phytochemicals against Rhizopus oryzae: interaction with ergosterol.

Mucormycoses are emerging infections that have high rates of morbidity and mortality. They show high resistance to antifungal agents, and there is a limited therapeutic arsenal currently available, therefore, there is a great need to give priority to testing therapeutic agents for the treatment of mucormycosis. Along this line, the use of essential oils and phytoconstituents has been emphasized as a new therapeutic approach. The objective of this work was to investigate the antifungal activity of the essential oil (EO) of Thymus vulgaris, and its constituents thymol and p-cymene against Rhizopus oryzae, through microbiological screening, determination of minimal inhibitory concentration (MICs) and minimal fungicidal concentration (MFCs), effects on mycelial growth and germination of sporangiospores and interaction with ergosterol. The MIC of EO and thymol varied 128-512 µg/mL, but the MFC of EO and thymol varied 512-1024 µg/mL and 128-1024 µg/mL, respectively. The results also showed that EO and thymol significantly inhibited mycelial development and germination of sporangiospores. Investigation of the mechanism of antifungal action showed that EO and thymol interact with ergosterol. These data indicate that EO of T. vulgaris and thymol possess strong antifungal activity, which can be related to their interaction with ergosterol, supporting the possible use of these products in the treatment of mucormycosis.

Atividade antifúngica de imidas cíclicas contra Cryptococcus / Antifungal activity of cyclic imides Cryptococcus neoformans

A criptococose é uma infecção fúngica causada pela levedura Cryptococcus neoformans que acomete tanto hospedeiros normais quanto imunocomprometidos. Nos últimos anos, o número de cepas resistentes a váriso antifúngicos de uso clínico tem apresentado um vertiginoso crescimento. Neste contexto, é de fundamental importância a pesquisa de novas alternativas terapêuticas, através do estudo com produtos naturais, substâncias isoladas e sintéticas, como as imidas cíclicas. O presente trabalho teve como objetivo investigar a atividade antifúngica das imidas cíclicas frente a cepas de Cruptococcus neofornans. A triagem antifúngica foi realizada utilizando a técnica de difusão em meio sólido. Para a determinação da concentração inibitória mínima, foi empregada a técnica da microdiluição. Foram testadas naftalimidas, succimidas e maleimidas. Dentre estas substâncias, as maleimidas ... De acordo com os resultados , as maleimidas surgem como candidatas a antifúngicos por atuarem contra uma espécie de microorganismo que comumente causa infecções.

Antifungal activity of Cymbopogon winterianus jowitt ex bor against Candida albicans

Candida albicans is an opportunistic yeast and a member of the normal human flora that commonly causes infections in patients with any type of deficiency of the immune system. The essential oils have been tested for antimycotic activity and pose much potential as antifungal agents. This work investigated the activity of the essential oil of Cymbopogon winterianus against C. albicans by MIC, MFC and time-kill methods. The essential oil (EO) was obtained by hydrodistillation using a Clevenger-type apparatus. It was tested fifteen strains of C. albicans. The MIC was determined by the microdilution method and the MFC was determined when an aliquot of the broth microdilution was cultivated in SDA medium. The phytochemical analysis of EO showed presence of citronellal (23,59 percent), geraniol (18,81 percent) and citronellol (11,74 percent). The EO showed antifungal activity, and the concentrations 625 µg/mL and 1250 µg/mL inhibited the growth of all strains tested and it was fungicidal, respectively. The antimicrobial activity of various concentrations of EO was analyzed over time, it was found concentration-dependent antifungal activity, whose behavior was similar to amphotericin B and nystatin.

Antifungal activity of Cymbopogon winterianus jowitt ex bor against Candida albicans.

Candida albicans is an opportunistic yeast and a member of the normal human flora that commonly causes infections in patients with any type of deficiency of the immune system. The essential oils have been tested for antimycotic activity and pose much potential as antifungal agents. This work investigated the activity of the essential oil of Cymbopogon winterianus against C. albicans by MIC, MFC and time-kill methods. The essential oil (EO) was obtained by hydrodistillation using a Clevenger-type apparatus. It was tested fifteen strains of C. albicans. The MIC was determined by the microdilution method and the MFC was determined when an aliquot of the broth microdilution was cultivated in SDA medium. The phytochemical analysis of EO showed presence of citronellal (23,59%), geraniol (18,81%) and citronellol (11,74%). The EO showed antifungal activity, and the concentrations 625 µg/mL and 1250 µg/mL inhibited the growth of all strains tested and it was fungicidal, respectively. The antimicrobial activity of various concentrations of EO was analyzed over time, it was found concentration-dependent antifungal activity, whose behavior was similar to amphotericin B and nystatin.

Biological activity of Herissantia crispa (L) Brizicky / Atividade biológica da Herissantia crispa (L) Brizicky

O extrato metanólico bruto (EMeOH) das partes aéreas da Herissantia crispa (L.) Brizicky, planta rica em flavonóides e que não possui estudos farmacológicos, foi testada para avaliar sua atividade sob os parâmetros comportamentais e determinar a dose letal 50 (DL50) em camundongos; atividade antimicrobiana e antiulcerogênica. O EMeOH (5000 mg/kg, v.o. ou 2000 mg/kg i.p.) não alterou os parâmetros comportamentais e não causou mortes nos animais. A amostra vegetal em estudo inibiu o crescimento bacteriano. O EMeOH (750 mg/kg) apresentou atividade anti-diarréica. O EMeOH (250, 500 e 750 mg/kg) foi capaz de inibir as lesões gástricas induzidas pelo 0,3 M HCl/etanol 60 por cento em camundongos. Desta forma, pode-se concluir que a planta em estudo apresenta atividade antiulcerogênica, entretanto, se faz necessário avaliar tal atividade através de modelos mais específicos e estudar o mecanismo de ação pelo qual a amostra vegetal protege a mucosa gástrica.

The crude methanol extract (EMeOH) of the aerial parts of Herissantia crispa (L.) Brizicky, plant riches in flavonoids and without pharmacological studies, was tested to value its activity under the behaviour parameters and to determine the lethal dose (LD50) in mice; antimicrobial and antiulcerogenic activities. The EMeOH (5,000 mg/kg, v.o. or 2,000 mg/kg i.p.) did not alter the behaviour parameters and there were not mice deaths. The extract inhibited the bacterial growth. The EMeOH (750 mg/kg) showed anti-diarroeal activity. The EMeOH (250, 500 and 750 mg/kg) decreased the gastric lesions induced by 0.3 M HCl/ethanol 60 percent in mice. In conclusion, the EMeOH presents anti-ulcerogenic activity;, however it is necessary to value the antiulcerogenic activity in more specific models and to study the action mechanism by which the vegetable sample protects the gastric mucosa.

Antimicrobial effectiveness of maleimides on fungal strains isolated from onychomycosis

This study aimed to analyze the effectiveness of maleimides as inhibitors on the growth of fungal strains isolated from onychomycosis by the solid medium diffusion procedure. The results showed a promising antifungical activity of the assayed maleimides with formation of fungal growth inhibition halos oscillating between diameter 10 and 23mm. MIC was 100æg/mL for 3,4-dichloro-N-phenyl-methyl-maleimide and 3,4-dichloro-N-phenyl-propil-maleimide and 200æg/mL for 3,4-dichloro-N-phenyl-maleimide, 3,4-dichloro-N-phenyl-ethyl-maleimide and 3,4-dichloro-N-phenyl-buthyl-maleimide.

Este estudo objetivou analisar a efetividade de maleimidas como inibidores do crescimento de cepas fúngicas isoladas de onicomicoses através da técnica de difusão em meio sólido. Os resultados mostraram destacável atividade antifúngica das maleimidas ensaiadas com a formação de halos de inibição do crescimento fúngico com diâmetros oscilando entre 10 e 23mm. A CIM encontrada foi 100æg/mL para 3,4-dicloro-N-fenil-metil-maleimida e 3,4-dicloro-N-fenil-propil-maleimida e 200æg/mL para 3,4-dicloro-N-fenil-maleimida, 3,4-dicloro-N-fenil-etil-maleimida e 3,4-dicloro-N-fenil-butil-maleimida.

Espectro antimicrobiano do óleo essencial de Rosmarinus officinalis L / Antimicrobial spectrum of the essential oil of rosmarinus officinallis L

Objetivos: Avaliar in vitro o espectro antimicrobiano do óleo essencial de Rosmrinus officinalis sobre cepas de espécies bacterianas e leveduriformes. Material e Métodos: O óleo essencial de R. officinalis foi obtido a partir da técnica de arraste com vapor d'agua. A avalição da atividade antimicrobiana foi realizada através da técnica de difusão em meio sólido / processos cavidades em placas. Foi testado o perfil de sensibilidade de cepas dos seguintes microorganismos: Staphylococcus aureus, S. epidermidis, Echerichia coli, Bacillus cereus, B. subutillis, C. albicans, C. krusei, C. tropicalis, C. stellatoidea e C. guilliermondii. Resultados: os dados obtidos revelaram destacável poder inibitório do crescimento dos microrganismos testados, principalmente sobre as cepas de fungos leveduriformes, representada por espécies de Candida. O referido óleo foi capaz de inibir o crescimento de todas as cepas de fungos leveduriformes testadas, apresentando halos de inibição do crescimento de até 21mm de diâmetro. Conclusão: Os resultados demonstraram considerável propriedade antimicrobiana do referido óleo essencial, pricipalmente quando da sua ação sobre fungos leveduriformes