Examinando por Autor "Martinez, Rolando"

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  • Miniatura
    Ítem
    Estudio teórico de la isomerización del ácido maleico en ácido fumárico: un enfoque basado en el concepto de superficie de energía potencial
    (Sociedade Brasileira de Química, 2010) Ugarte, Ricardo; Salgado, Guillermo; Martinez, Rolando; Navarrete, José
    A comparative study based on potential energy surfaces (PES) of 2-butanedioic and hypothetic 2-butanedioic/HCl acids is useful for understanding the maleic acid isomerization. The PES enables locating conformers of minimum energy, intermediates of reactions and transition states. From contour diagrams, a set of possible reaction paths are depicted interconnecting the proposed structures. The study was carried out in absentia and in the presence of the catalyst (HCl), using an solvatation model provided by the Gaussian software package. Clearly, the effect of HCl is given by new reaction paths with lower energetic barriers in relation to the reaction without catalyzing.
  • Miniatura
    Ítem
    Study on the cytotoxic activity of drimane sesquiterpenes and nordrimane compounds against cancer cell lines
    (MDPI AG, 2014) Montenegro, Ivan; Tomasoni, Giacomo; Bosio, Claudia; Quiñones, Natalia; Madrid, Alejandro; Carrasco, Hector; Olea, Andres; Martinez, Rolando; Cuellar, Mauricio; Villena, Joan
    Twelve drimanes, including polygodial (1), isopolygodial (2), drimenol (3), confertifolin (4), and isodrimenin (5), were obtained from natural sources. Semi-synthetic derivatives 6-12 were obtained from 1 and 2, and cytotoxic activity was evaluated in vitro against cancer cell lines (HT-29, MDA-MB231, DHF, MCF-7, PC-3, DU-145, and CoN). IC50 values were determined at concentrations of 12.5-100 ìM of each compound for 72 h. In addition, it was found that polygodial (1), 8, and 12 induced changes in mitochondrial membrane permeability in CoN, MCF-7, and PC-3 cells. © 2014 by the authors.