Abstract. Due to increasing drug resistance by Candida species, especially in hospitals, the search for new antifungal agents has intensified. The incorporation of the coumarin scaffold into several nitrogen-containing heterocyclic moieties reportedly increases antimicrobial efficiency. The aim of this study was to design and synthesize a series of simple coumarin-linked triazole derivatives and test their possible antifungal activity against four Candida species. Docking simulations were conducted to explore the binding properties of the test compounds and compare them to reported data on fluconazole, the reference drug. Starting from 3-acetylcoumarins, coumarins 2a-d, 3a-c and 4a-d were obtained in high yields. The concentration of each compound needed to inhibit the Candida species was determined by serial dilution. An inhibition of 62% of C. albicans was produced by 2b (300 µg/ml), 87% of C. tropicalis by 3a (100 µg/ml), 89% of C. parapsilosis by 3a (500 µg/ml), and 87% of C. glabrata by 4a (300 µg/ml). The values of antifungal activity were similar for the coumarin derivatives and fluconazole, the latter of which induced 90% inhibition of the four yeasts at 500 µg/ml. According to the docking simulations, the interactions at the active site of the lanosterol 1,4-demethylase enzyme (CYP51) are similar for the test compounds and fluconazole. The subcellular location of the derivatives was identified as the mitochondrion. These coumarins are characterized by structural simplicity, with the simplest structures showing better antifungal activity than fluconazole. Further research is needed to isolate CYP51 and directly test its inhibition by coumarin derivatives.

Resumen. Una serie de moléculas de cumarina-triazol se sintetizaron y evaluaron contra diferentes especies de Candida. Las cumarinas 2a-d, 3a-c y 4a-d se obtuvieron utilizando como material de partida las 3-acetilcumarinas en altos rendimientos. La concentración necesaria de las moléculas para mostrar actividad antifúngica contra las cuatro especies de Candida se determinó mediante un método de diluciones seriadas. Se reporta un 62% de inhibición de C. albicans usando 2b (300 µg/ml), 87% de inhibición contra C. parapsilosis por 3a (500 µg/ml), y un 87% de inhibición a C. glabrata por 4a (300 µg/ml). El efecto de las cumarinas es comparado con el fármaco de referencia fluconazol, que induce un 90% de inhibición en todas las cepas usando 500 µg/ml. Los resultados del estudio Docking muestran que las interacciones de todas las moléculas en el sitio activo de la enzima CYP51 son similares a las interacciones presentadas por el fluconazol. Finalmente, tomando ventaja de las propiedades fluorescentes de las cumarinas, la localización subcelular y penetración de los compuestos, fue localizada en las mitocondrias. Las cumarinas reportadas, además de presentar sencillez estructural, también presentan valores de inhibición de las cepas comparables, y en los casos mencionados, mejores que el fármaco de referencia.

Abstract: In this paper we give an overview of the current applications of nanomaterials and nanocomposites in fields related to human health, specifically on applications to prevent the spread of pathogenic microorganisms (bacteria, protozoa and fungi) in a hospital environment through the use of nanotechnological approaches. In addition, we make a general description of how nanoparticles and nanocomposites can be effective against microorganisms resistant to conventional antibiotics. For the evaluation of the antimicrobial activity of various nanomaterials that are intended to be introduced to the market, various methods and procedures are followed according to international standards such as: International Organization for Standardization, American Association of Textile Chemists and Colorists, American Standard and Testing of Materials, Japanese Industrial Standards, among others.

Resumen: En este artículo damos una revisión general de las aplicaciones actuales de nanomateriales y nanocompuestos en campos relacionados con la salud humana, específicamente sobre las aplicaciones para prevenir la propagación de microrganismos patógenos (bacterias, protozoarios y hongos) en un ambiente hospitalario mediante el uso de enfoques nanotecnológicos. Además, hacemos una descripción general de cómo las nanopartículas y los nanocompuestos pueden ser efectivos contra microrganismos resistentes a los antibióticos convencionales. Para la evaluación de la actividad antimicrobiana de diversos nanomateriales que se pretenden introducir al mercado, se siguen diversos métodos y procedimientos de acuerdo con estándares internacionales tales como: International Organization for Standardization (iso), American Association of Textile Chemists and Colorists, American Standard and Testing of Materials, Japanese Industrial Standards, entre otros.

Protein glycosylation pathways, commonly found in fungal pathogens, offer an attractive new area of study for the discovery of antifungal targets. In particular, these post-translational modifications are required for virulence and proper cell wall assembly in Candida albicans, an opportunistic human pathogen. The C. albicans MNS1 gene is predicted to encode a member of the glycosyl hydrolase family 47, with 1,2-mannosidase activity. In order to characterise its activity, we first cloned the C. albicans MNS1 gene into Escherichia coli, then expressed and purified the enzyme. The recombinant Mns1 was capable of converting a Man9GlcNAc2 N-glycan core into Man8GlcNAc2 isomer B, but failed to process a Man5GlcNAc2-Asn N-oligosaccharide. These properties are similar to those displayed by Mns1 purified from C. albicansmembranes and strongly suggest that the enzyme is an ±1,2-mannosidase that is localised to the endoplasmic reticulum and involved in the processing of N-linked mannans. Polyclonal antibodies specifically raised against recombinant Mns1 also immunoreacted with the soluble ±1,2-mannosidases E-I and E-II, indicating that Mns1 could share structural similarities with both soluble enzymes. Due to the high degree of similarity between the members of family 47, it is conceivable that these antibodies may recognise ±1,2-mannosidases in other biological systems as well.