In vitro susceptibility of the Sporothrix brasiliensis to aqueous extracts of the green tea (Camellia sinensis L. Kuntze)

Resumo

Sporotrichosis is a zoonotic mycosis, which Sporothrix brasiliensis is the prevalent agent in cats and dogs with this disease in Brazil. Itraconazole is used for the treatment, but the emergence of resistance has encouraged the search for therapeutic alternatives in medicinal plants. The benefits properties of green tea (Camellia sinensis L. Kuntze) include antifungal activity, but there are no data in sporotrichosis. This study aimed to evaluate the in vitro anti-Sporothrix spp. activity of green tea. Infusion and decoction of dried leaves of green tea were prepared at 10% and tested through broth microdilution test (CLSI M38-A2), as well as itraconazole for veterinary use. Nine clinical isolates of S. brasiliensis from cats and dogs with sporotrichosis in South region of Rio Grande do Sul, Brazil, and one standard strain of S. schenckii were tested. The results were expressed in minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC). All isolates were inhibited by infusion and decoction (MIC90 of 3.125 mg ml-1 for both extracts), without statistic difference, but the fungicidal activity was weak or no occured (MFC90 > 50 mg ml-1 for both). In itraconazole, S. brasiliensis were sensitive at the MIC50 of 2 μg ml-1 and S. schenckii to MIC of 0.0625 μg ml-1, but the antifungal resistance was observed (MIC90 and MFC50/90 > 16 μg ml-1). For the first time, the satisfactory inhibitory activity of the infusion and decoction of green tea make its promising in the treatment of sporotrichosis and more studies are needed for its use.