Browsing by Autor "Reinaldo Molina"

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Computational Investigation of the Potential Antileishmanial Mechanism of the Nitroindazole Derivative VATR131
(Multidisciplinary Digital Publishing Institute, 2025) Omar Casanova-Alvarez; Niurka Mollineda-Diogo; Aliuska Morales Helguera; Vicente J. Arán; Reinaldo Molina; Norberto Sánchez‐Cruz; Yendrek Velásquez-López; Yunierkis Pérez‐Castillo
Background: Neglected tropical diseases (NTDs) significantly impact global health, particularly affecting impoverished communities. Among these diseases, leishmaniasis, caused by protozoan parasites of the genus Leishmania and transmitted through sandfly vectors, remains a challenge due to limited therapeutic options. Current treatments often suffer from significant limitations, such as high toxicity, limited efficacy, and the emergence of drug resistance. Objectives: This study investigates the potential antileishmanial mechanism of action of nitroindazole derivatives, specifically evaluating the compound VATR131, a molecule with notable selectivity and potency against Leishmania infantum. Methods: We employed computational methodologies, including target fishing, molecular docking, and atomistic molecular dynamics simulations, to identify and characterize potential molecular targets of VATR131. Results: The analysis revealed cysteine peptidase A as a promising target potentially mediating the antileishmanial activity of VATR131. Molecular dynamics simulations suggest critical hydrophobic interactions and hydrogen bonds between the compound and its most likely receptor, thus offering deeper insights into its potential mechanism of action. Conclusions: These findings contribute to the development of novel and effective therapies for leishmaniasis, highlighting the need for experimental validation and continued investigation of nitroindazole derivatives as promising therapeutic candidates.
Development and validation of a gas chromatography with a flame ionization detector method for quantitative analysis of four major fatty acids extracted shark liver oil
(2021) Pedro César Quero–Jiménez; Lester A. Arias Felipe; María Elisa Jorge Rodríguez; Reinaldo Molina; Julio Omar Prieto Garcı́a; Jorge B. de la Torre López; Osvaldo Norman Montenegro
Context: The shark liver of the species Ginglimostoma cirratun, Carcharhinus longimanus, and Carcharhinus falciformis, captured in the north-central coast of Cuba are a source of oil, whose content of major fatty acids could be used in its quality control. Aims: To develop a simple and robust gas chromatography with a flame ionization detector (GC-FID) method that is suitable for routine analysis of four major fatty acids extracted shark liver oil. Methods: Four major fatty acid content in shark liver oil pool of species Ginglimostoma cirratun, Carcharhinus longimanus, and Carcharhinus falciformis, was analyzed through the gas chromatography with a GC-FID. The fatty acids were analyzed as methyl esters derivatives, using 5% aqueous sulfuric acid in methanol. The method was validated in terms of linearity, precision, accuracy, specificity and limit of detection and quantitation. Results: Under the optimum analytical conditions, the analysis revealed that each target component was well separated with satisfactory recoveries and reproducibility. The method linearity was found to be high with good determination coefficient values for all target components. The evaluation of the matrix effect, demonstrated, that there is not interference from substances other than analysis. The method was also found to be accurate, precise and reproducible and it was applied to the quantitative determination of the fatty acid content in shark liver oil pool; oleic acid was the most abundant fatty acid (22.69%), followed by palmitic (18.85%), stearic (6.01 %) and myristic acid (0.40 %). Conclusions: The GC-FID developed method is reliable and suitable for determination of four major fatty acids in shark liver oil pool.
Local Cuban bentonite clay as potential low-cost adsorbent for shark liver oil pool purification
(2021) Pedro César Quero–Jiménez; Lester A. Arias Felipe; Julio Omar Prieto Garcı́a; María Elisa Jorge Rodríguez; Jorge B. de la Torre López; Osvaldo Norman Montenegro; Reinaldo Molina
Context: The shark liver of the species Ginglimostoma cirratun, Carcharhinus longimanus, and Carcharhinus falciformis, captured in the north-central coast of Cuba are a source of oil, that when extracted it must be purified due to its bad smell, taste and the amount of impurities it has. Aims: To evaluate the purification of the shark liver oil (SLO) pool of species Ginglimostoma cirratun, Carcharhinus longimanus, and Carcharhinus falciformis, by Cuban bentonite clay. Methods: The effects of bentonite dose, contact time and speed rate were studied using the 23 factorial designs. The parameters are evaluated in the experiment design: acidity value, p-anisidine value, peroxide value, Totox value and Bleaching performance. Response Surface Methodology modeling techniques were applied to model the process and their performance and predictive capabilities of the response (purification efficiency) was also examined. Results: The experiments showed that the oil is suitable for consumption after the purification process. The best treatment, which could reduce the impurities in the SLO pool, was a treatment with bentonite dose at 80 g/L, time at 15 min, and speed rate at 250 rpm. Cuban bentonite clay is a promising adsorbent candidate for the removal of impurities of the SLO. Conclusions: The local Cuban bentonite clay can be used as potential low-cost adsorbent for shark liver oil pool purification, as showed the experiments.
Local Cuban bentonite clay: composition, structure and textural characterization
(National Geology and Mining Service, 2021) Pedro César Quero–Jiménez; Lester Alejandro Arias Felipe; Julio Omar Prieto Garcı́a; María Elisa Jorge Rodríguez; Jorge Basilio de la Torre López; Osvaldo Norman Montenegro; Reinaldo Molina; Inés Tiscornia
The physic and chemical characterization of the bentonite clay from the Chiqui Gómez deposit, central Cuba, (Cuban bentonite clay) shows that it is mainly constituted by sodium montmorillonite (>90%), with a structural formula for one-layer unit determined as (Na3.99Al0.01)(Al1.11Fe3+0.49Mg0.18Ti0.07)(Ca0.24Na0.15K0.01)O10(OH)2. The Cuban bentonite clay has a specific surface area of 80 m2g-1, a pore volume of about 0.0776 cm3g-1, 61% porosity and both N2 adsorption-desorption isotherms exhibit a hysteresis loop of IV type. The thermogravimetric analysis (TGA) of the studied mineral presents the first endothermic peak, characteristic of montmorillonite, in 48.1 ºC and others less accentuated (80.8, 94.0, 119.8 ºC) characteristic of sodium montmorillonite, that corresponds to the loss of water, and can be extended up to 250 ºC. The FT-IR spectra show the existence of Si-OH, Al-Al-OH, Al-Fe-OH, Al-Mg-OH and Si-O-Si functional groups in all clay samples, bands between 1,120 and 461 cm-1 correspond to phyllosilicate structures and OH stretching vibrations were observed. pH at the point of zero charge (pHPZC) obtained has a value of 8.1, which allows montmorillonite to be classified as basic.