Antifungal activity of promethazine and chlorpromazine against planktonic cells and biofilms of Cryptococcus neoformans/Cryptococcus gattii complex species.

Cryptococcus neoformans/Cryptococcus gattii are fungal pathogens that affect the central nervous system, mainly in immunocompromised individuals. Due to the limited pharmacological arsenal available for the treatment of cryptococcosis associated with cases of antifungal resistance of Cryptococcus spp. reported in some studies, the search for new compounds with antifungal potential becomes relevant. Thus, the objective of this study was to evaluate the inhibitory effect of phenothiazines (promethazine and chlorpromazine) on C. neoformans/C. gattii planktonic cells and biofilms. In vitro planktonic susceptibility testing was performed using the broth microdilution assay. The effect of phenothiazines was evaluated against biofilm formation and mature Cryptococcus biofilms. Biofilm morphology and ultrastructure were also evaluated by scanning electron microscopy. Promethazine and chlorpromazine showed antifungal activity against planktonic cells, with minimum inhibitory concentrations of 8-32 µg/ml and 4-16 µg/ml, respectively. As for biofilm formation, phenothiazines reduced biomass by 60% and metabolic activity by 90% at 64 µg/ml; while in mature biofilms, reductions of 85% and 90% in biomass and metabolic activity, respectively, were observed at 1024 µg/ml. Promethazine and chlorpromazine were also able to disrupt and fragment biofilms. In conclusion, promethazine and chlorpromazine have antifungal activity against planktonic cells and biofilms of Cryptococcus spp. These data show the potential of promethazine and chlorpromazine as antibiofilm drugs.

Sodium butyrate inhibits planktonic cells and biofilms of Trichosporon spp.

Trichosporon spp. have been increasingly recognized as an important pathogen of invasive and disseminated infections in immunocompromised patients. These species are prone to form biofilms in medical devices such as catheters and prosthesis, which are associated with antifungal resistance and therapeutic failure. Therefore, new antifungals with a broader anti-biofilm activity need to be discovered. In the present study we evaluate the inhibitory potential of sodium butyrate (NaBut) - a histone deacetylase inhibitor that can alter chromatin conformation - against planktonic and sessile cells of T. asahii and T. inkin. Minimum inhibitory concentration (MIC) of NaBut against planktonic cells was evaluated by microdilution and morphological changes were analyzed by optical microscopy on malt agar supplemented with NaBut. Biofilms were evaluated during adhesion, development and after maturation for metabolic activity and biomass, as well as regarding ultrastructure by scanning electron microscopy and confocal laser scanning microscopy. NaBut inhibited the growth of planktonic cells by 50% at 60 mM or 120 mM (p < 0.05) and also reduced filamentation of Trichosporon spp. NaBut reduced adhesion of Trichosporon cells by 45% (10xMIC) on average (p < 0.05). During biofilm development, NatBut (10xMIC) reduced metabolic activity and biomass up to 63% and 81%, respectively (p < 0.05). Mature biofilms were affected by NaBut (10xMIC), showing reduction of metabolic activity and biomass of approximately 48% and 77%, respectively (p < 0.05). Ultrastructure analysis showed that NaBut (MIC and 10xMIC) was able to disassemble mature biofilms. The present study describes the antifungal and anti-biofilm potential of NaBut against these opportunist emerging fungi.

Extratos de Moringa oleifera e Vernonia sp. sobre Candida albicans e Microsporum canis isolados de cães e gatos e análise da toxicidade em Artemia sp. / Moringa oleifera and Vernonia sp. extracts against Candida albicans and Microsporum canis isolates from dogs and cats and analysis of toxicity to Artemia sp.

O aumento da incidência das infecções fúngicas, bem como o registro crescente de resistência e falha terapêutica, têm impulsionado a realização de estudos de prospecção de fitoquímicos com propriedades antifúngicas. Diante do exposto, o presente estudo investigou o potencial antifúngico de extratos de Baccharis ligustrina, B. schultzii, Croton jacobinensis, Licania rigida, Moringa oleifera, Vernonia sp. e V. brasiliana, e de óleos essenciais de Lippia alba (Quimiotipos 1, 2, 3 e 4) e Ocimum gratissimum. Inicialmente, foi realizada uma avaliação qualitativa da atividade antifúngica de cada amostra por meio do método de difusão em ágar, frente a cepas de Candida albicans e Microsporum canis, mostrando que apenas os extratos de M. oleifera (MLF-C) e Vernonia sp. (TVS-H) apresentaram atividade frente a C. albicans e M. canis, com halos de inibição =10mm. Também foram determinadas a concentração inibitória mínima (CIM), frente a 12 cepas de C. albicans e M. canis, e a toxicidade aguda de MLF-C e TVS-H, através de protocolos do Clinical and Laboratory Standards Institute (CLSI) e ensaio com Artemia sp., respectivamente. A CIM (80 por cento) de MLF-C e TVS-H variou de 0,156 a 2,5mg mL-1 frente C. albicans e de 0,039 a 1,25 e 0,039 a 0,625mg mL-1 para M. canis, respectivamente. A CIM (100 por cento) de MLF-C e TVS-H variou de 0,625 a 2,5mg mL-1 frente C. albicans é de 0,039 a 2,5 e 0,078 a 1,25mg mL-1 para M. canis, respectivamente. As doses letais (DL50) para o MLF-C e TVS-H foram de 201,09 e 204,17mg mL-1, respectivamente, sendo, portanto, demonstrada a baixa toxicidade desses extratos. Os extratos de M. oileifera e Vernonia sp. apresentaram atividade antifúngica frente cepas de C. albicans e M. canis, abrindo a perspectiva de estudos para caracterização dos seus componentes bioativos.

The increase in the incidence of fungal infections and the frequent report of resistance and therapeutic failure has promoted the performance of phytochemical screening for compounds with antifungal properties. Based on this, the present study investigated the antifungal potential of extracts of Baccharis ligustrina, B. schultzii, Croton jacobinensis, Licania rigida, Moringa oleifera, Vernonia sp. and V. brasiliana and of essential oils of Lippia alba (Chemotypes 1, 2, 3 and 4) and Ocimum gratissimum. Initially, a qualitative evaluation of the antifungal activity of each vegetal sample against strains of Candida albicans and Microsporum canis, through the agar diffusion method, was performed. Extracts of M. oleifera (MLF-C) and Vernonia sp. (TVS-H) presented activity against C. albicans and M. canis with inhibition halos =10mm. Then, minimum inhibitory concentrations (MICs) for MLF-C and TVS-H against 12 strains of C. albicans and M. canis were determined through the methodology established by the Clinical and Laboratory Standards Institute (CLSI), and acute toxicity tests against Artemia sp. were performed for both extracts. MICs (80 percent) for MLF-C and TVS-H varied from 0.156 to 2.5mg mL-1 against C. albicans and from 0.039 to 1.25mg mL-1 and 0.039 to 0.625mg mL-1 against M. canis, respectively. MICs (100 percent) for MLF-C and TVS-H varied from 0.625 to 2.5mg mL-1 for C. albicans and from 0.039 to 2.5mg mL-1 and 0.078 to 1.25mg mL-1 against M. canis, respectively. Lethal doses (DL50) of MLF-C and TVS-H were 201.09 and 204.17mg mL-1, respectively, being, therefore, demonstrated the low toxicity of these extracts. M. oleifera and Vernonia sp. extracts presented in vitro antifungal activity against C. albicans and M. canis, creating perspectives for the development of studies on the characterizations of their bioactive components.