From drug repurposing studies, this work aimed to evaluate the activity of different pyrazinoic acid (POA) derivatives against Sporothrix brasiliensis. The POA esters were prepared and characterized as previously reported by classical esterification reactions, with good to excellent yields. Sporothrix brasiliensis isolates from cats (n=6) and standard strains of S. brasiliensis and S. schenckii were used to assess the antifungal activity of the POA derivatives through broth microdilution assay (CLSI M38-A2). Among the tested compounds, molecules 3 and 4 showed fungistatic and fungicidal activities against all Sporothrix spp. strains, and the obtained MIC and MFC values ranged from 2.12 to 4.24 mg/mL and from 1.29 to 5.15 mg/mL, respectively. Compound 2 and 5 were active as in vitro inhibitors of fungal growth, but showed weak fungicidal activity, while molecules 1 and POA itself were inactive. The results suggest the activity of POA derivatives against Sporothrix spp. may be dependent on the lipophilicity. In addition, the antifungal susceptibility of the isolates to itraconazole was performed, showing that two Sporothrix isolates from cats were itraconazole-resistant. Compounds 3 and 4 were also active against these itraconazole-resistant isolates, indicating a possible alternative route to the standard mode of action of itraconazole.

Abstract The study aimed to evaluate the anti-Sporothrix sp. activity of the essential oil of Origanum majorana Linn. (marjoram), its chemical analysis, and its cytotoxic activity. A total of 18 fungal isolates of Sporothrix brasiliensis (n: 17) from humans, dogs and cats, and a standard strain of Sporothrix schenckii (n: 1) were tested using the broth microdilution technique (Clinical and Laboratory Standard Institute - CLSI M27-A3) and the results were expressed in minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC). The MIC50 and MIC90 of itraconazole against S. brasiliensis were 2 µg/mL and 8 µg/mL, respectively, and the MFC50 and MFC90 were 2 µg/mL and >16 µg/mL, respectively, with three S. brasiliensis isolates resistant to antifungal. S. schenckii was sensitive at MIC of 1 µg/mL and MFC of 8 µg/mL. For the oil of O. majorana L., all isolates were susceptible to MIC of ≤2.25-9 mg/mL and MFC of ≤2.25-18 mg/mL. The MIC50 and MIC90 were ≤2.25 mg/mL and 4.5 mg/mL, respectively, and the MFC50/90 values were twice more than the MIC. Twenty-two compounds were identified by gas chromatography with a flame ionization detector (CG-FID) and 1,8-cineole and 4-terpineol were the majority. Through the colorimetric (MTT) assay, the toxicity was observed in 70-80% of VERO cells between 0.078 and 5 mg/mL. For the first time, the study demonstrated the satisfactory in vitro anti-Sporothrix sp. activity of marjoram oil and further studies are needed to ensure its safe and effective use.

RESUMO Casos de esporotricose em humanos e animais sem resposta clínica satisfatória têm aumentado, sinal de alarme para o surgimento de cepas resistentes aos antifúngicos convencionais. A urgente busca por alternativas terapêuticas tem incentivado as pesquisas em plantas medicinais com atividade anti-Sporothrix spp. Um levantamento bibliográfico foi realizado com base em artigos científicos sobre a atividade antifúngica in vitro e in vivo de óleos essenciais e extratos de plantas preparados em diferentes solventes contra o complexo Sporothrix schenckii. A metodologia do estudo consistiu em uma revisão bibliográfica em Google Scholar, Science Direct, Pubmed, Bireme e Springer link com artigos desde 1986 até 2015. Foram encontradas 141 espécies de plantas já investigadas, das quais 100 espécies concentradas em 39 famílias botânicas apresentaram atividade anti-Sporothrix spp. confirmada. Combretaceae, Asteraceae e Lamiaceae representaram as famílias botânicas com maior número de espécies vegetais com potencial antifúngico, empregando diferentes metodologias. Entretanto, há poucos estudos com plantas medicinais em infecção experimental animal comprovando sua atividade no tratamento da esporotricose. Reforça-se a necessidade de mais pesquisas relacionadas à padronização de metodologias in vitro e a estudos in vivo relacionados à segurança e potencial tóxico dessas plantas com atividade anti-Sporothrix spp.

ABSTRACT Cases of sporotrichosis in humans and animals without satisfactory clinical response have increased, a warning sign of strains resistant to conventional antifungal agents. The urgent search for alternative therapies was an incentive for research on medicinal plants with anti-Sporothrix spp. properties. A bibliographic survey was performed based on scientific papers about in vitro and in vivo antifungal activity of essential oils and extracts of plants in differents solvents against the fungal of the Sporothrix schenckii complex. The study methodology consisted of a literature review in Google Scholar, Science Direct, Pubmed, Bireme and Springer link with papers from 1986 to 2015. We found 141 species of plants that were investigated, of which 100 species were concentrated in 39 botanical families that had confirmed anti-Sporothrix activity. Combretaceae, Asteraceae and Lamiaceae represented the botanical families with the greatest number of plants species with antifungal potential, using different methodologies. However, there are few studies with medicinal plants in experimental infection in animals that prove their activity in the treatment of sporotrichosis. It reinforces the need for further research related to standardization of in vitro methodologies and in vivo studies related to safety and to toxicity potential of these plants with anti-Sporothrix spp. activity.

The oral microbiota of humans and animals is made up of a wide variety of yeasts and bacteria, but microbiota of dogs is not totally described. Although such identification is an important step to establish the etiopathogenesis and adequate therapy for the periodontal disease The aim of this study was to evaluate and correlate oral alterations with the presence of yeasts in oral cavity of female dogs. After clinical evaluation samples from healthy and from dogs with oral diseases were obtained from three different oral sites by swabs, curettes, millimeter periodontal probes and HA membrane tip in cellulose ester. Yeast identification was performed through macroscopic and microscopic colony features and biochemical tests. Dental calculus was the most prevalent occurrence in the oral cavity of 59 females. However, the isolation of yeasts was significantly higher (p < 0.05) in animals suffering from halitosis. Eleven yeast species were identified, namely: Malassezia pachydermatis, Rhodotorula spp., Candida albicans, C. catenulata, C. famata, C. guilliermondii, C. parapsilosis, C. intermedia, Trichosporon asahii, T. mucoides and Cryptococcus albidus. It could be concluded that the yeasts are part of the microbiota from the different sites of the oral cavity of the female canines studied without causing any significant alterations except halitosis.