Browsing by Author "Castro Álvarez, Alejandro"

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    Experimental and In Silico Studies to Unravel the Antioxidant and Antibacterial Properties of Lichen Metabolites from Pseudocyphellaria compar and Pseudocyphellaria nudata
    (2026) Cuellar, Mauricio A.; Mejia Forero, Jessica Carolina; Quintero Pertuz, Helena; Castro Álvarez, Alejandro; Mellado, Marco; Vera Quezada, Waleska; Montenegro Rizzardini, Gloria; Espinosa Bustos, Christian Marcelo; Bridi, Raquel; Salas, Cristian O.
    Lichens are a source of diverse compounds with a wide range of biological activities, making them of significant interest for novel drug development. In this study, metabolites were extracted from Lobariaceae lichens, and their antioxidant and antibacterial properties were experimentally investigated and explained using various computational approaches. Specifically, four lichen metabolites were analyzed using three methods to assess their antioxidant capacity. Antibacterial activity assays were conducted against four pathogens, and the minimum inhibitory concentrations (MICs) of the most promising compounds were determined. Ab initio studies were performed to evaluate radical stability. A pharmacological target responsible for the antibacterial effect was identified, and possible binding sites and modes were studied in silico. Metabolite IX, physciosporin, exhibited the highest antioxidant activity, which was associated with the theoretical stability of the radical. Additionally, IX exhibited an MIC of 0.97 μg/mL against S. pyogenes, surpassing the potency of streptomycin. The RecA protein was identified as a potential target, and a possible binding site and pattern of interactions at that site were described. Finally, IX showed low cytotoxicity in human cancer cell lines and was predicted to have favorable oral absorption properties, supporting its potential as a promising antioxidant and antibacterial agent against S. pyogenes.
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    Synthesis, antitumoral activity, and in silico studies on Smoothened receptor of new 2,6,9-trisubstituted purine derivatives
    (Elsevier B.V., 2025) Espinosa Bustos, Christian Marcelo; Zarate Méndez, Ana María; Castro Álvarez, Alejandro; Guerrero, Simón; Kogan, Marcelo J.; Salas Sánchez, Cristian Osvaldo
    © 2024 Elsevier B.V.In this work, a series of 30 new 2,6,9-trisubstituted purine derivatives were synthesised and evaluated in silico as potential ligands of the Smoothened (SMO) receptor, as well as their ability to inhibit growth in Hedgehog (Hh)-dependent and Hh-independent cancer cell lines. The synthesis involved a convergent strategy, conventional methods and microwave irradiation. Initial antitumour evaluation was performed by testing cell growth inhibition in seven cancer cell lines and one non-neoplastic cell line (HEK-293) at 50 μM. IC50 values were determined for compounds showing < 50 % cell viability. Compounds 7l and 9j showed promising results with high cytotoxicity in three Hh-dependent cell lines and low cytotoxicity in HEK-293 cells. Compound 7l was more potent and selective than gemcitabine in BxPC-3, AsPc-1 and MIA-PaCa-2 cells and more than 5-fluorouracil in HT-29 cells, while 9j was more potent and selective than 5-fluorouracil in HCT116 and HT-29 cells. Molecular docking studies in SMO allowed the recognition of two binding sites related to ligand size and purine substitution patterns, while 7l bound to the top pocket (TMD-1), 9j bound to a deeper pocket (TMD-2). This study provides new evidence supporting the purine ring as a privileged scaffold for the development of new antitumour drugs targeting the SMO receptor.