Browsing by Author "Espinoza, Luis"

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    LTA-mediated synthesis and complete assignment of H-1 and C-13 NMR data of two natural 11-nordrimanes: isonordrimenone and polygonone
    (WILEY, 2007) Moreno Osorio, Luis; Espinoza, Luis; Cuellar, Mauricio; Preite, Marcelo
    Two naturally occurring 11-nordrimanes were synthesized, and their H-1 and C-13 NMR spectra were unambiguously assigned in full for the first time. Copyright (c) 2007 John Wiley & Sons, Ltd.
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    New Dimethoxyaryl-Sesquiterpene Derivatives with Cytotoxic Activity Against MCF-7 Breast Cancer Cells: From Synthesis to Topoisomerase I/II Inhibition and Cell Death Mechanism Studies
    (2025) Araque, Ileana; Vergara, Rut; Mella, Jaime; Aranguiz, Pablo; Espinoza, Luis; Salas, Cristián O.; Fernández Barrero, Alejandro; Quilez del Moral, José Francisco; Villena, Joan; Cuellar, Mauricio
    Breast cancer is a prevalent type of cancer worldwide, leading to both high incidence and mortality, and hence, effective and safe drugs are needed. Because of this, the use of natural products and their derivatives has become a popular strategy for developing new chemotherapeutic agents. In this study, 17 new sesquiterpene-aryl derivatives were synthesized using (−)-drimenol as the starting material. The cytotoxicity of these semi-synthetic derivatives was determined in MCF-7 cells, a breast cancer model, and in a non-tumor cell line, MCF-10, to evaluate selectivity. The results show that five of these sesquiterpene derivatives had IC50 values between 9.0 and 25 µM. Of these, compound 14c stands out for its higher cytotoxicity in MCF-7 cells but lower cytotoxicity in MCF-10 cells, being more selective than daunorubicin (selective index values of 44 and 28, respectively). In addition, compound 14c induced oxidative stress in MCF-7 cells, activated caspases-3/7, and selectively inhibited topoisomerase II (TOP2) versus topoisomerase I (TOP1) in MCF-7 cells. In silico studies allowed us to propose a binding mode for 14c to the TOP2 DNA complex to validate the experimental results. Therefore, this study demonstrated the importance of aryl-sesquiterpene structures and their promising profiles in the search for new bioinspired antitumor drugs in natural products.
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    Solubility in supercritical carbon dioxide of two novel amine derivatives of 2,3-dichloronaphthalene-1,4-dione (dichlone)
    (2023) Schulz, Alex C.; Zacconi, Flavia C.; Cabrera, Adolfo L.; del Valle, Jose M.; Espinoza, Luis; de la Fuente, Juan C.
    Dichlone (2,3-dichloronaphthalene-1,4-dione) is an important antimicrobial agent for agriculture, which effectiveness could be improved by modifying its structure, while the recovery of high-purity synthesized derivatives from a reaction mixture could be accomplished by extracting them with supercritical carbon dioxide. Two new amine derivatives, 2-chloro-3-((4-chlorobenzyl)amino)naphthalene-1,4-dione (dCl-2B-Cl) and 2-chloro-3-((4-chlorophenethyl)amino)naphthalene-1,4-dione (dCl-3P-Cl), were synthesized from dichlone, and their solubility in supercritical carbon dioxide was measured afterwards at (313, 323 and 333) K and a pressure range from (8-33) MPa. Experimental solubilities spanned from (10.3 center dot 10(-6) to 22.1 center dot 10(-6)) mol center dot mol(-1) for dCl-2B-Cl, and from (32.7 center dot 10(-6) to 131 center dot 10(-6)) mol center dot mol(-1) for dCl-3P-Cl. The solubility data of the dichlone family (dichlone, dCl-2B-Cl, dCl-3P-Cl, 2-(benzylamino)-3-chloronaphthalene-1,4-dione (dCl-2B) and 2-chloro-3-(phenethylamino)naphthalene-1,4-dione (dCl-3P)) was compared using three models, i.e., the Chrastil equation, the Molecular Connectivity Indices model, and the Statistical Associating Fluid Theory of Variable Range and Mie Potential equation of state, to identify the quantitative structure-property relationship between them. Solubility had an inverse relation with solute size and polarity, but there were some exceptions that could be explained by performing a stereochemical analysis, which showed that steric effects involved in the folding of dCl-3P and dCl-3P-Cl provided them a better geometry for solvation than dCl-2B and dCl-2B-Cl, respectively, making them more soluble. This demonstrates that the solute geometry is an important factor in the solvation process, and it must be represented accurately to develop better predictive models.
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    Synthesis and plant growth-activity of three new brassinosteroids analogues
    (2000) Espinoza, Luis; Bulat Jara, Felipe Alfonso; Coll, Danahe; Coll Machado, Francisco; Preite, Marcelo Daniel; Cortés Marescotti, Manuel
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    Tautomeric, spectroscopic, DFT calculations and X-ray studies on O2N-4-C6H4-NHN=Q(COCH3)(2)
    (2007) Bustos, Carlos; Sánchez, Christian; Martínez, Rolando; Ugarte, Ricardo; Schott Verdugo, Eduardo Enrique; Carey, Desmond Mac-Leod; Garland, María Teresa; Espinoza, Luis