Estudo do potencial antifúngico e do mecanismo de ação do timol contra cepas de Candida parapsilosis resistentes ao fluconazol e a anfotericina B / Study of the antifungal potential and mechanism of action of thymol against strains of Candida parapsilosis resistant to fluconazole and amphotericin B

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.

Antifungal Activity of Phytochemicals against Samples of Penicillium.

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.

Investigation of Melissa officinalis L. Essential Oil for Antifungal Activity against Cladosporium carrionii.

Cladosporium carrionii is considered the most important pathogenic species of genus because of the numerous cases of disease which causes in the world. Due to its antifungal resistance, these fungal infections are difficult to treat. Given the broad biological activity displayed by natural products, essential oils obtained from plants are often investigated to determine their antimicrobial activity. Aims: Therefore, we identified components of Melissa officinalis L. essential oil, investigating in vitro antifungal activity against strains of C. carrionii. Methodology: Identification of the chemical composition of the oil was performed by gas chromatography coupled to a mass spectrometer (GC-MS). The antifungal activity of M. officinalis L. essential oil was investigated against 08 strains of C. carrionii determining minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC), effects on mycelial growth, and conidial germination. Results: The GC-MS results revealed 4 major components; geranial (52%), citral (38.90%), trans- β-caryophyllene (1.22%), and germacrene D (0.84%). M. officinalis L. essential oil inhibited the growth of all (100%) of the strains of C. carrionii tested. The MIC and MFC were established at 256 μg/ml. Inhibition of radial mycelial growth began at 128 μg/ml (MIC/2), and at both 2 x MIC and 4 x MIC the inhibition was complete. We also observed significant conidial germination inhibition at all concentrations when compared to the control (P<0.05). The inhibition increased with concentration so that at 2 x MIC complete (100%) conidia germination inhibition was observed. Conclusion: Finally, our study results point to M. officinalis L. essential oil as a potential antifungal agent against C. carrionii.

Distribution ofddermatophytes from soils of urbn and rural areas of cities of paraiba state, Brazil / Distribuicao de dermatofitos isolados de solos de cidades do Estado da Paraiba, Brasil

SUMMARY The dermatophytes, keratinophilic fungi, represent important microorganisms of the soil microbiota, where there are cosmopolitan species and others with restricted geographic distribution. The aim of this study was to broaden the knowledge about the presence of dermatophytes in soils of urban (empty lots, schools, slums, squares, beaches and homes) and rural areas and about the evolution of their prevalence in soils of varying pH in cities of the four mesoregions of Paraiba State, Brazil. Soil samples were collected from 31 cities of Paraiba State. Of 212 samples, 62% showed fungal growth, particularly those from the Mata Paraibana mesoregion (43.5%), which has a tropical climate, hot and humid. Soil pH varied from 4.65 to 9.06, with 71% of the growth of dermatophytes occurring at alkaline pH (7.02 - 9.06) (ρ = 0.000). Of 131 strains isolated, 57.3% were geophilic species, particularly Trichophyton terrestre (31.3%) and Mycrosporum gypseum (21.4%). M. nanum and T. ajelloi were isolated for the first time in Paraiba State. The zoophilic species identified were T. mentagrophytes var. mentagrophytes (31.3 %) and T. verrucosum (7.6 %), and T. tonsurans was isolated as an anthropophilic species. The soils of urban areas including empty lots, schools, slums and squares of cities in the mesoregions of Paraiba State were found to be the most suitable reservoirs for almost all dermatophytes; their growth may have been influenced by environmental factors, soils with residues of human and/or animal keratin and alkaline pH. .

RESUMO Os dermatófitos, fungos queratinofílicos, representam importantes microrganismos da microbiota do solo, onde existem espécies cosmopolitas e outras de distribuição geográfica restrita. Este estudo teve como objetivo ampliar o conhecimento da distribuição de dermatófitos do solo proveniente de áreas urbanas (terrenos baldios, escolas, favelas, praças, praias e residências) e rurais de quatro mesorregiões paraibanas e da influência do pH na adaptação desse grupo de fungos. Amostras de solos urbanos e rurais foram coletadas de 31 cidades do estado da Paraíba, Brasil. De 212 amostras 62% apresentaram crescimento fúngico, destacando-se a Mesorregião da Mata Paraibana (43.5%), a qual apresenta clima tropical, quente e úmido. O pH das amostras de solo variou de 4.65 a 9.06, com crescimento de 71% dos dermatófitos em pH alcalino (7.02 - 9.06) (ρ = 0.000). Das 131 cepas isoladas 57.3% eram espécies geofílicas, destacando-se Trichophyton terrestre (31.3%) e Microsporum gypseum (21.4%). M. nanum e T. ajelloi foram isolados pela primeira vez no estado da Paraíba. Entre as espécies zoofílicas foram identificadas T. mentagrophytes var. mentagrophytes (31.3%) e T. verrucosum (7.6%) e como espécie antropofílica foi isolada T. tonsurans. Os solos de terrenos baldios, escolas, favelas e praças de cidades paraibanas são os reservatórios mais adequados dos dermatófitos, cujo crescimento pode ter sido influenciado por fatores ambientais, solos com resíduos de queratina humana e ou animal e pH alcalino. .

Actividad antifúngica del aceite esencial de Eugenia caryophyllata sobre cepas de Candida tropicalis de aislados clínicos / Antifungal activity of the essential oil of Eugenia caryophyllata on Candida tropicalis strains from clinical isolates

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.