Drimane Sesquiterpene Alcohols with Activity against Candida Yeast Obtained by Biotransformation with Cladosporium antarcticum.

Fungal biotransformation is an attractive synthetic strategy to produce highly specific compounds with chemical functionality in regions of the carbon skeleton that are not easily activated by conventional organic chemistry methods. In this work, Cladosporium antarcticum isolated from sediments of Glacier Collins in Antarctica was used to obtain novel drimane sesquiterpenoids alcohols with activity against Candida yeast from drimendiol and epidrimendiol. These compounds were produced by the high-yield reduction of polygodial and isotadeonal with NaBH4 in methanol. Cladosporium antarcticum produced two major products from drimendiol, identified as 9α-hydroxydrimendiol (1, 41.4 mg, 19.4% yield) and 3ß-hydroxydrimendiol (2, 74.8 mg, 35% yield), whereas the biotransformation of epidrimendiol yielded only one product, 9ß-hydroxyepidrimendiol (3, 86.6 mg, 41.6% yield). The products were purified by column chromatography and their structure elucidated by NMR and MS. The antifungal activity of compounds 1-3 was analyzed against Candida albicans, C. krusei and C. parapsilosis, showing that compound 2 has a MIC lower than 15 µg/mL against the three-pathogenic yeast. In silico studies suggest that a possible mechanism of action for the novel compounds is the inhibition of the enzyme lanosterol 14α-demethylase, affecting the ergosterol synthesis.

Drimane Sesquiterpene Aldehydes Control Candida Yeast Isolated from Candidemia in Chilean Patients.

Drimys winteri J.R. (Winteraceae) produce drimane sesquiterpenoids with activity against Candida yeast. In this work, drimenol, polygodial (1), isotadeonal (2), and a new drimane α,ß-unsaturated 1,4-dialdehyde, named winterdial (4), were purified from barks of D. winteri. The oxidation of drimenol produced the monoaldehyde drimenal (3). These four aldehyde sesquiterpenoids were evaluated against six Candida species isolated from candidemia patients in Chilean hospitals. Results showed that 1 displays fungistatic activity against all yeasts (3.75 to 15.0 µg/mL), but irritant effects on eyes and skin, whereas its non-pungent epimer 2 has fungistatic and fungicide activities at 1.9 and 15.0 µg/mL, respectively. On the other hand, compounds 3 and 4 were less active. Molecular dynamics simulations suggested that compounds 1-4 are capable of binding to the catalytic pocket of lanosterol 14-alpha demethylase with similar binding free energies, thus suggesting a potential mechanism of action through the inhibition of ergosterol synthesis. According to our findings, compound 2 appears as a valuable molecular scaffold to pursue the future development of more potent drugs against candidiasis with fewer side effects than polygodial. These outcomes are significant to broaden the alternatives to treat fungal infections with increasing prevalence worldwide using natural compounds as a primary source for active compounds.

Evaluación de la sensibilidad diagnóstica de tres técnicas de laboratorio para la infección por influenza A: inmunocromatografía, IFD e IFD con citocentrifugado versus RPC-TR / Evaluation of three laboratory methods diagnostic sensitivity in influenza A infection: RIDT, DFA and DFA with cytocentrifugation versus RT-PCR

Introduction: The specific diagnosis of influenza A infection makes it possible to control its spread, decreases the unnecessary use of antibiotics, clinical procedures and laboratory test, and allows early recognition of outbreaks. Different technologies are currently available in Chile for this purpose. Objective: The study presented here compares the sensitivity for influenza A virus detection of immunocromatography (RIDT), direct fluorescent antibodies-DFA and DFA with cytocentrifugation against the gold standard, RT-PCR. Material and Methods: In 175 nasal swab samples influenza A RIDT and RT-PCR were performed. Another 1689 nasal swab samples were tested by DFA and RT-PCR for influenza A. Finally, 29 nasal swab samples confirmed as Influenza A positive by RT-PCR were tested by DFA with cytocentrifugation. Results: The RIDT, DFA and DFA + cytocentrifugation sensitivity was 47,3%, 57,2% and 72,4%, respectively. Discussion and Conclusion: Their lower cost and faster turnaround time when compared to PCR make RIDT and DFA the tests of choice in diagnostic laboratories in Chile. However, their low sensitivity and NPV, especially during low season, makes more sensitive diagnostic tools necessary to confirm the results. In our study cytocentrifugation increased DFA sensitivity from 57% to 72%.

Introducción: El diagnóstico específico de influenza permite controlar la diseminación de la enfermedad, disminuir el uso de antimicrobianos, procedimientos clínicos y exámenes, e identificar rápidamente brotes. Diferentes tecnologías están actualmente disponibles en Chile para este propósito. Objetivo: Comparar la sensibilidad diagnóstica para la infección por el virus influenza A de las técnicas inmunocromatografía, inmunofluorescencia directa-IFD e IFD con citocentrifugado contra el estándar de oro, RPC-TR. Materiales y Método: En 175 muestras de hisopado nasofaríngeo se realizó inmunocromatografía y RPC-TR para influenza A. Otras 1.689 muestras de hisopado nasofaríngeo fueron procesadas mediante IFD y RPC-TR para influenza A. Finalmente, en 29 muestras de hisopado nasofaríngeo, confirmadas positivas para influenza A mediante RPC-TR, se realizó IFD con citocentrifugado. Resultados: La sensibilidad de la inmunocromatografía, IFD e IFD + citocentrifugado fue de 47,3%, 57,2% y 72,4%, respectivamente. Discusión y Conclusión: El menor costo y tiempo de respuesta de las técnicas rápidas (inmunocomatografía e IFD) en relación a la RPC-TR hacen que se mantengan como exámenes de rutina en los laboratorios diagnósticos del país. Sin embargo, su baja sensibilidad y VPN, especialmente durante períodos de baja prevalencia, obligaría a confirmar los resultados negativos con técnicas más sensibles. En nuestra comparación la citocentrifugación mejoró la sensibilidad de la IFD de 57% a 72%.

[Evaluation of three laboratory methods diagnostic sensitivity in influenza A infection: RIDT, DFA and DFA with cytocentrifugation versus RT-PCR]. / Evaluación de la sensibilidad diagnóstica de tres técnicas de laboratorio para la infección por influenza A: inmunocromatografía, IFD e IFD con citocentrifugado versus RPC-TR.

INTRODUCTION: The specific diagnosis of influenza A infection makes it possible to control its spread, decreases the unnecessary use of antibiotics, clinical procedures and laboratory test, and allows early recognition of outbreaks. Different technologies are currently available in Chile for this purpose. OBJECTIVE: The study presented here compares the sensitivity for influenza A virus detection of immunocromatography (RIDT), direct fluorescent antibodies-DFA and DFA with cytocentrifugation against the gold standard, RT-PCR. MATERIAL AND METHODS: In 175 nasal swab samples influenza A RIDT and RT-PCR were performed. Another 1689 nasal swab samples were tested by DFA and RT-PCR for influenza A. Finally, 29 nasal swab samples confirmed as Influenza A positive by RT-PCR were tested by DFA with cytocentrifugation. RESULTS: The RIDT, DFA and DFA + cytocentrifugation sensitivity was 47,3%, 57,2% and 72,4%, respectively. DISCUSSION AND CONCLUSION: Their lower cost and faster turnaround time when compared to PCR make RIDT and DFA the tests of choice in diagnostic laboratories in Chile. However, their low sensitivity and NPV, especially during low season, makes more sensitive diagnostic tools necessary to confirm the results. In our study cytocentrifugation increased DFA sensitivity from 57% to 72%.