ABSTRACT
Objetivo: investigar a suscetibilidade de cepas fúngicas de Candida parapsilosis isoladas de sangue humano frente ao timol, bem como seu mecanismo de ação. Metodologia: foram utilizadas técnicas de microdiluição em placas de 96 poços para determinar a concentração inibitória mínima (CIM) e concentração fungicida mínima (CFM). Além disso, foram realizados testes com o sorbitol e o ergosterol para investigar a ação do timol na parede e na membrana celular fúngica respectivamente. Resultados: nos testes de CIM e CFM, foi observado que as cepas de C. parapsilosis são resistentes ao fluconazol e a anfotericina B, no entanto, o timol desempenhou efeito fungicida com razão CFM/CIM entre 1 e 2. Além disso, a CIM do timol não aumentou quando o sorbitol ou o ergosterol foi adicionado no meio, sugerindo fortemente que este monoterpeno não age na parede celular fúngica ou por ligação ao ergosterol na membrana plasmática. Conclusão: portanto, esses resultados contribuem para a elucidação do mecanismo de ação do timol, sugerindo outros possíveis alvos de interação fármaco-receptor. No entanto, mais investigações de caráter enzimático e molecular em modelos in vitro são necessários para que se possa elucidar completamente o modo de ação desse promissor monoterpeno.
Objective: to investigate the susceptibility of fungal strains of Candida parapsilosis isolated from human blood against thymol, as well as its mechanism of action. Methodology: microdilution techniques were used in 96-well plates to determine minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC). In addition, tests were performed with sorbitol and ergosterol to investigate the action of thymol on the wall and on the fungal cell membrane respectively. Results: in the CIM and CFM tests, it was observed that C. parapsilosis strains are resistant to fluconazole and amphotericin B, however, thymol had a fungicidal effect with MFC/MIC ratio between 1 and 2. In addition, thymol MIC did not increase when sorbitol or ergosterol was added in the medium, strongly suggesting that this monoterpene does not act on the fungal cell wall or by binding to ergosterol on the plasma membrane. Conclusion: therefore, these results contribute to the elucidation of the mechanism of action of thymol, suggesting other possible targets of drug-receptor interaction. However, further investigations of enzymatic and molecular character in in vitro models are necessary to fully elucidate the mode of action of this promising monoterpene.
Subject(s)
Humans , Thymol , Fluconazole , Amphotericin B , Candidiasis, Invasive , Candida parapsilosis , Anti-Infective Agents , Antifungal Agents , Sorbitol , ErgosterolABSTRACT
Introdução: aproximadamente 75% das mulheres saudáveis experimentam pelo menos um episódio sintomático de candidíase vulvovaginal (CVV) durante sua vida. Objetivo: avaliar a atividade antifúngica contra cepas de C. tropicalis dos enantiômeros (R)-(+) e (S)-(-)-citronelal [(R)-(+) e (S)-(-)-CT] em associação com cetoconazol. Metodologia: o efeito antifúngico de ambos os enantiômeros foram quantificados e classificados como fungicida ou fungistático a partir dos resultados obtidos da microdiluição em meio líquido RPMI1640 para a obtenção da concentração inibitória mínima (CIM) e da concentração fungicida mínima (CFM). Foram realizados ensaios de associação do antifúngico padrão, cetoconazol com os fitoconstituintes por difusão em Agar e os resultados foram classificados como sinérgicos, antagônicos e indiferentes. Resultados: a CIM50 e a CFM50 dos compostos (R)-(+) e (S)-(-)-citronelal foram respectivamente 16 e 64µg/mL e 2×CIM. Houve sinergismo para todas as cepas testadas com ambos os compostos, porém com maior efeito do enantiômero (S)-(-)-CT sobre as cepas LM 665 e LM 255 em relação ao enantiômero (R)-(+)-CT. Conclusão: os compostos naturais deste estudo mostraram efeito fungicida sobre as cepas testadas, bem como efeito sinérgico significativo quando associado ao cetoconazol
Subject(s)
Female , Candida tropicalisABSTRACT
The prevalence of candidiasis in the world is high. Candida species are able to create superficial and systemic infections. Candida albicans is an opportunistic pathogen, causing mycoses in immunocompromised patients as well as long-term antibiotic users. The present study objective was to evaluate in vitro anti-candida effect of this compost isolated from Praxelis clematidea. The minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC) were determined by the broth microdilution techniques. We also investigated possible flavonoid 5,7,4´trimethoxflavone (TMF) action on cell walls (0.8 M sorbitol) and cell membranes (TMF to ergosterol binding). The MIC50 of flavonoid were 64 𝜇g/mL and tha MFC50 was 64 𝜇g/mL. Involvement with the cell wall and ergosterol binding were comproved as possible mechanisms of action. In conclusion the flavonoid showed in vitro antifungal potential against strains of C. albicans.
ABSTRACT
Aims: The incidence of fungal infections has increased over the last ten years and fungi of the genus Penicillium can be found in various substrates and affect immunocompromised people, hospitalized patients, many animals and plants, as well as compromise the quality of air indoors. The current situation of indiscriminate use of antibiotics and the consequent resistance of microorganisms to conventional antimicrobial therapy has been stimulating researchers to seek alternative sources of antimicrobial compounds, among them the medicinal plants. The tendency of getting phytochemicals from extracts, fractions, fixed or essential oils obtained from plant species is currently observed. In this context, the present study aims to evaluate the in vitro antifungal activity of seven phytochemicals (geraniol, carvacrol, thymol, linalool, p-cymene, terpinolene and citral) against twelve samples of Penicillium. Place of Study: Laboratory tests were carried out at the Mycology Laboratory Department of Pharmaceutical Sciences, located in the Health Sciences Center (CCS) of the Federal University of Paraíba (UFPB). Methodology: Firstly, screening was carried out to find the phytochemical with the best activity by determining the minimum inhibitory concentration (MIC) by the broth microdilution technique. Following, the tests were proceeded with thymol to determine of minimum fungicidal concentration (MFC). Results: Through analysis of results, it is observed that carvacrol, thymol and citral showed the best activities of the samples of Penicillium studied. The MIC values were 256 mg / mL, for carvacrol and citral, and 128 mg / mL, for thymol (compound showed better results). The thymol had its MIC 90 established at 128 mg / mL, inhibiting, at this concentration, 92% of the tested samples. Analyzing compared to MIC and MFC, it was observed that thymol presented CFM values similar to CIM values for 1/3 of the samples, showing also values greater than 1024 mg / mL for only two samples. The CFM value ranged from 128 μg/ml to 1024 μg/ml. Conclusion: The thymol is a promising new possibility among the products with antifungal activity against Penicillium, however if the performance is needed further studies, deeper, about their mechanism of action and toxicity, as well as in vivo tests, aiming a possible application therapy.
ABSTRACT
Most of the flavonoids are considered as constitutive antimicrobial ingredients, especially those belonging to prenylated flavonoids, flavones and isoflavones. In the study, the flavonoid 5,7,4’- trimethoxyflavone was evaluated for its antifungal effects. Four fungal strains were used in the study for activities, Candida krusei – LM 9700, Candida krusei – LM 656, Candida krusei– LM 13 and Candida krusei – LM08. All the microorganism strains were obtained from the Laboratory of Mycology collection. Microdilution method was used for antifungal assay of the flavonoid. The results were also compared with the standard drug, Nistatin (100 UI/mL). The obtained results showed activity fungistatic against Candida krusei strains.
ABSTRACT
Candidiasis is an opportunistic fungal infection caused by Candida yeasts. In Brazil, C. tropicalis is the second most frequently isolated microorganism after C. albicans. The arising of strains resistant to conventional antifungal agents has increased the search for new alternatives from natural products, especially essential oils. This research investigated essential oil activity against strains of C. tropicalis by disk diffusion method. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were also determinate. In the disk diffusion, the essential oils of Cinnamomum zeylanicum, Eugenia caryophyllata and Origanum vulgare had the highest inhibition zones values. MIC and MFC values of E. caryophyllata essential oil were 512 and 1024 ug/mL, respectively. MIC and MFC amphotericin B values were identical (2 ug/mL). Therefore, it was concluded that E. caryophyllata essential oil has strong antifungal activity and may be subject to further studies.
La candidiasis es una infección fúngica oportunista causada por levaduras del género Candida. En Brasil, la especie C. tropicalis esta siendo aislada frecuentemente, es el segundo microorganismo más aislado después de C. albicans. La aparición de cepas resistentes a los antifúngicos convencionales ha aumentado la búsqueda de nuevas alternativas provenientes de productos naturales, especialmente los aceites esenciales. En este estudio se investigó la actividad de los aceites esenciales contra las cepas de C. tropicalis, utilizando el método de difusión en disco, la concentración inhibitoria mínima (CIM) y la concentración fungicida mínima (CFM). En el método de difusión en disco, con los aceites esenciales de Cinnamomum zeylanicum, Eugenia caryophyllata y Origanum vulgare se obtuvieron mayores valores de inhibición. La CIM y CFM del aceite esencial de Eugenia caryophyllata fueron 512 y 1024 ug/mL, mientras que los de la anfotericina B fueron idénticos, 2 ug/mL. Por lo tanto, se puede concluir que el aceite esencial de E. caryophyllata tiene potente actividad antifúngica y puede ser objeto de nuevos estudios sobre esta actividad.