Avaliação in vitro do efeito inibitório dos óleos essenciais de capim limão e gerânio encapsulados em micropartículas de quitosana frente a cepas de Sporothrix SPP.

Abstract

Sporotrichosis is a subcutaneous mycosis caused by cosmopolitan, thermodymorphic fungi of the genus Sporothrix, which are transmitted mainly by the sapronotic route. In Brazil, sporotrichosis appears in the South and Southeast regions with a distinct characteristic: zoonotic transmission, which occurs via contact with contaminated felines or through lesions caused by these animals. The number of cases of the disease has increased and the panorama shows its spread to other regions, such as the Northeast. The current treatment for the disease is classic antifungal drugs such as itraconazole. However, due to the toxicity of these drugs and reports of relapses and refractory infections, therapeutic alternatives have been sought. Knowing that essential oils and chitosan are natural substances with antimicrobial activity, the aim of this study was to evaluate the antifungal effect of lemongrass and geranium essential oils isolated and encapsulated in chitosan microparticles against strains of Sporothrix spp. in their filamentous and yeast planktonic form. The aim was also to assess whether strains isolated from different regions had different sensitivity profiles. To this end, sensitivity tests were carried out with the planktonic cells of Sporothrix globosa, Sporothrix brasiliensis and Sporothrix schenckii, and with the yeast form of Sporothrix brasiliensis, using the broth microdilution methodology to obtain the minimum inhibitory concentrations of the test compounds capable of inhibiting fungal growth. For the planktonic forms, the chitosan microparticle with lemongrass oil (MQCL) obtained values ranging from 0.5 to 2 μg/mL against S. brasiliensis, 1 μg/mL against S. globosa and from 0.5 to 2 μg/mL against S. schenckii. For encapsulated geranium oil (MQG), the values were 0.5 to 2 for S. brasiliensis, and 0.5 to 2 for S. globosa and S. schenckii. Finally, in the yeast form, MQCL showed 1 to 4 μg/mL and MQG showed 1 μg/mL. These values are close to, or even better than, those obtained with the classic antifungal itraconazole, the drug of choice for treating sporotrichosis, which showed concentrations of 0.5 to 4 μg/mL (filamentous) and 0.5 to 2 μg/mL (yeast) against S. brasiliensis, 1 μg/mL against S. globosa and 0.5 to 1 for S. schenckii. Thus, the microparticles loaded with essential oils proved promising for the development of new treatments for sporotrichosis and it was not possible to observe any difference in sensitivity profiles between strains from different regions.