Método convencional para o diagnóstico de micoses: um estudo comparativo

Introdução: O método clássico para o diagnóstico de micoses é realizado pelo Exame micológico direto (EMD) e cultural, que possibilita a visualização de estruturas fúngicas vegetativas e estruturas reprodutivas, respectivamente. Essa combinação é fundamental para reduzir possíveis erros analíticos e aumentar a precisão do diagnóstico.Métodos: Com a finalidade de verificar a frequência do EMD e cultural, e comparar seus parâmetros de sensibilidade e especificidade, realizamos uma análise retrospectiva entre Janeiro de 2018 e Maio de 2020 de 1603 laudos micológicos oriundos de um laboratório de análises clínicas, localizado em Porto Alegre.Resultados: Após a análise dos laudos observamos que a maioria dos casos apresentaram o EMD negativo com cultura positiva (36,24%). Na sequência, 30,87% dos casos foram de amostras negativas e 25,57% dos laudos foram positivos para ambos os exames. A minoria dos casos (7,29%) apresentaram o EMD positivo com cultura negativa.Conclusão: Esta análise revelou que o exame cultural é mais sensível e específico, demonstrando uma maior confiabilidade no diagnóstico. Entretanto, vale ressaltar que a realização dos exames em conjunto, além de reduzir possíveis erros analíticos, proporcionam um diagnóstico melhor fundamentado

Chemical composition variability in the Uncaria tomentosa (cat's claw) wild population

Uncaria tomentosa (cat’s claw) is a vine widely distributed throughout the South-American rainforest. Many studies investigating the chemical composition of cat’s claw have focused on the pentacyclic (POA) and tetracyclic oxindole alkaloids (TOA), quinovic acid glycosides (QAG), and polyphenols (PPH). Nevertheless, it is still uncertain how environmental factors affect chemical groups. The aim of this work was to better understand the influence of environmental factors (geographic origin, altitude, and season) on cat’s claw chemical composition. Stem bark, branches and leaf samples were extracted and analyzed by HPLC-PDA. The data obtained were explored by multivariate analysis (HCA and PCA). Higher amounts of oxindole alkaloids and PPH were found in leaves, followed by stem bark and branches. No clear relationship was verified among geographic origin or altitude and chemical composition, which remained unchanged regardless of season (dry or rainy). However, three oxindole alkaloid chemotypes were clearly recognized: chemotype I (POA with cis D/E ring junction); chemotype II (POA with trans D/E ring junction); and chemotype III (TOA). Thus, environmental factors appear to have only a minor influence on the chemical heterogeneity of the cat’s claw wild population. Nevertheless, the occurrence of different chemotypes based on alkaloid profiles seems to be clea

Chemical differentiation between Uncaria tomentosa and Uncaria guianensis by LC-PDA, FT-IR and UV methods coupled to multivariate analysis: A reliable tool for adulteration recognition

Uncaria guianensis (UG) and Uncaria tomentosa (UT) are widely found in the South America rainforest. Both species, popularly known as cat's claw, can be easily differentiated in natural state through their morphological characteristics. However, the discrimination of their derivatives, such as dried extracts, is limited to differences in their chemical composition. This work establishes differentiation criteria between both cat's claw species by multivariate analysis from FT-IR, UV, and LC-PDA data, as well as for adulteration recognition in UT stem bark. Eight authentic UT and UG stem bark samples and eighteen UT samples spiked with UG at three levels (10%, 30% and 50%, w/w) were extracted and analyzed by FT-IR analysis; direct UV analysis; UV analysis after basification and complexation with KOH and AlCl3, respectively; LC-PDA analysis of oxindole alkaloids, quinovic acid glycosides, and polyphenols. Classification (SIMCA and k-NN models) and calibration (PCR and PLS models) multivariate models were applied for adulteration recognition and quantification of their level, respectively. The authentic UT samples could not be differentiated those purposely spiked with UG from LC-PDA analysis of oxindole alkaloids. In contrast, LC-PDA analysis of polyphenols and UV analysis coupled to SIMCA and PLS multivariate models, allowed the differentiation between UT and UG and adulteration recognition in UT. Flavonoids were key compounds in both cases. Both UV and LC-PDA analysis of polyphenols coupled to multivariate analysis were effective for differentiation between cat's claw species, as well as adulteration recognition in the UT