Examinando por Autor "Salgado, F."

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  • Miniatura
    Ítem
    Secondary metabolite profiling of species of the genus usnea by UHPLC-ESI-OT-MS-MS
    (MDPI AG, 2018) Salgado, F.; Albornoz, L.; Cortéz, C.; Stashenko, E.; Urrea-Vallejo, K.; Nagles, E.; Galicia-Virviescas, C.; Cornejo, A.; Ardiles, A.; Simirgiotis, M.; García-Beltrán, O.; Areche, C.
    Lichens are symbiotic associations of fungi with microalgae and/or cyanobacteria, which are considered among the slowest growing organisms, with strong tolerance to adverse environmental conditions. There are about 400 genera and 1600 species of lichens and those belonging to the Usnea genus comprise about 360 of these species. Usnea lichens have been used since ancient times as dyes, cosmetics, preservatives, deodorants and folk medicines. The phytochemistry of the Usnea genus includes more than 60 compounds which belong to the following classes: depsides, depsidones, depsones, lactones, quinones, phenolics, polysaccharides, fatty acids and dibenzofurans. Due to scarce knowledge of metabolomic profiles of Usnea species (U. barbata, U. antarctica, U. rubicunda and U. subfloridana), a study based on UHPLC-ESI-OT-MS-MS was performed for a comprehensive characterization of their secondary metabolites. From the methanolic extracts of these species a total of 73 metabolites were identified for the first time using this hyphenated technique, including 34 compounds in U. barbata, 21 in U. antarctica, 38 in U. rubicunda and 37 in U. subfloridana. Besides, a total of 13 metabolites were not identified and reported so far, and could be new according to our data analysis. This study showed that this hyphenated technique is rapid, effective and accurate for phytochemical identification of lichen metabolites and the data collected could be useful for chemotaxonomic studies.
  • Miniatura
    Ítem
    Secondary Metabolites in Ramalina terebrata Detected by UHPLC/ESI/MS/MS and Identification of Parietin as Tau Protein Inhibitor
    (MDPI AG, 2016-08) Cornejo, A.; Salgado, F.; Caballero, J.; Vargas, R.; Simirgiotis, M.; Areche, C.
    Liquid chromatography coupled with mass spectrometry is an outstanding methodology for fast analysis of phenolic compounds in biological samples. Twenty two compounds were quickly and accurately identified in the methanolic extract of the Antarctic lichen Ramalina terebrata for the first time using ultra high pressure liquid chromatography coupled with photodiode array detector and high resolution mass spectrometry (UHPLC-PDA-Q/Orbitrap/MS/MS). In addition, the extract and the four compounds isolated from this species were tested for the inhibitory activity of tau protein aggregation, which is a protein involved in Alzheimer's disease (AD). All compounds showed null activity with the exception of parietin, which it was able to inhibit aggregation process of tau in a concentration range between 3 mu g/mL (10 mu M) to 28 mu g/mL (100 mu M). In addition, we show how parietin interact with tau (306)VQIVYK(311) hexapeptide inside of the microtubule binding domain (4R) with the help of molecular docking experiments. Finally, the constituents present in the methanolic extract could possibly contribute to the established anti-aggregation activity for this extract and this in-depth analysis of the chemical composition of R. terebrata could guide further research into its medicinal properties and potential uses.
  • Miniatura
    Ítem
    Synthesis and study of the trypanocidal activity of catechol-containing 3-arylcoumarins, inclusion in β-cyclodextrin complexes and combination with benznidazole
    (Elsevier B.V., 2022-03) Pozo-Martínez, J.; Salgado, F.; Liempi, A.; Kemmerling, U.; Mera-Adasme, R.; Olea-Azar, C.; Moncada-Basualto, M.; Borges, F.; Uriarte, E.; Matos, M.
    American trypanosomiasis or Chagas disease is caused by the protozoan parasite Trypanosoma cruzi, and is considered a neglected disease, being an important problem for public health. Benznidazole (BZN) is the drug used to treat the disease. However, it has limited efficacy and adverse side effects. Therefore, the development of new therapeutic alternatives is necessary. In this work, the trypanocidal activity and cytotoxicity of a series of catechol-containing 3-arylcoumarins, their combination with BZN, and the inclusion in β-cyclodextrins (β-CDs), were evaluated. The results obtained showed that the entire series has moderate trypanocidal activity on the trypomastigote form of the parasite, being the 3-(4′-bromophenyl)-6,7-dihydroxycoumarin (8) the most active compound (IC50 = 34 μM) and the most cytotoxic in Vero cells (IC50 = 162 μM) as well. By forming the inclusion complex 8-β-CDs, the trypanocidal activity and cytotoxicity decreased. In addition, the formation of inclusion complexes increased the solubility. The possible mechanism of action of 8 was evaluated and proved to be through the generation of oxidative stress. The combination with BZN presented a synergistic effect on the trypanocidal activity, reducing the necessary dose of BZN. The presence of a catechol in the studied scaffold seems to modulate the trypanocidal activity, and the combination of drugs proved to be a promising alternative strategy for treating the disease.