Publications by authors named "Francisco J Melendez"

Tuberculosis is a highly lethal bacterial disease worldwide caused by (). Caespitate is a phytochemical isolated from , a plant used in African traditional medicine that shows anti-tubercular activity, but its mode of action remains unknown. It is suggested that there are four potential targets in , specifically in the H37Rv strain: InhA, MabA, and UGM, enzymes involved in the formation of 's cell wall, and PanK, which plays a role in cell growth.

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Citrulline (CHNO) is an amino acid found in the body as a zwitterion. This means its carboxylic and amine groups can act as Lewis donors to chelate metal cations. In addition, citrulline possesses a terminal ureido group on its aliphatic chain, which also appears to coordinate.

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Article Synopsis
  • Modulation of the CXCL12-CXCR4 signaling axis is crucial for understanding its role in diseases like cancer and inflammation, with motixafortide being a leading drug that shows promise in treating various cancers.
  • Despite its potential, the exact mechanism of how motixafortide interacts with the CXCR4 receptor remains unclear, prompting a study using computational techniques to analyze this relationship.
  • The findings reveal that motixafortide stabilizes inactive states of CXCR4 through specific interactions between its cationic residues and CXCR4's acidic residues, providing insights for the future design of effective CXCR4 inhibitors.
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SARS-CoV-2 is the virus responsible for the COVID-19 pandemic. For the virus to enter the host cell, its spike (S) protein binds to the ACE2 receptor, and the transmembrane protease serine 2 (TMPRSS2) cleaves the binding for the fusion. As part of the research on COVID-19 treatments, several Casiopeina-analogs presented here were looked at as TMPRSS2 inhibitors.

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The anandamide is a relevant ligand due to its capacity of interacting with several proteins, including the T-type calcium channels, which play an important role in neuropathic pain and depression disorders. Hence, a detailed characterization of the chemical properties and conformational stability of anandamide may provide valuable information to understand its behavior in a biological context. Herein, conceptual DFT and QTAIM analyses were performed to theoretically characterize the chemical reactivity properties and the structural stability of conformations of anandamide, using the BP86/cc-pVTZ level of theory.

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The synthesis of six Mannich bases derived from hydroxycoumarins was carried out in moderate yields, two of these derivatives were described for the first time. Conformational analysis was performed through DFT theoretical calculations explaining the formation of stable six membered rings based on intramolecular hydrogen bonds within the structure. These findings were correlated with the antiproliferative activity.

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The synthesis and theoretical-experimental characterization of a novel diprotanated decavanadate is presented here due to our search for novel anticancer metallodrugs. Tris(2-pyridylmethyl)amine (TPMA), which is also known to have anticancer activity in osteosarcoma cell lines, was introduced as a possible cationic species that could act as a counterpart for the decavanadate anion. However, the isolated compound contains the previously reported vanadium (V) dioxido-tpma moieties, and the decavanadate anion appears to be diprotonated.

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The cannabinoid receptors (CB1/CB2) and the T-type calcium channels are involved in disorders associated with both physiological pain and depressive behaviors. Valuable pharmacological species carbazole derivatives such as the NMP-4, NMP-7, and NMP-181 (Neuro Molecular Production) regulate both biological entities. In this work, DFT calculations were performed to characterize theoretically their structural and chemical reactivity properties using the BP86/cc-pVTZ level of theory.

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Transition metal-based compounds have shown promising uses as therapeutic agents. Among their unique characteristics, these compounds are suitable for interaction with specific biological targets, making them important potential drugs to treat various diseases. Copper compounds, of which Casiopeinas are an excellent example, have shown promising results as alternatives to current cancer therapies, in part because of their intercalative properties with DNA.

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A theoretical study of the effect of the substituent Z on the gas phase acidity of substituted benzoic acids ZCHCOOH in terms of density functional theory descriptors (chemical potential, softness and Fukui function) is presented. The calculated gas phase Δ° values obtained were close to the experimental ones reported in the literature. The good relationship between the Δ° values and the electronegativity of ZCHCOOH and its fragments, suggested a better importance of the inductive than polarizability contributions.

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Photodynamic therapy (PDT) is an alternative treatment widely used against cancer. PDT requires molecular systems, known as photosensitizers (PS), which not only exhibit strong absorption at a particular wavelength range, but also need to be selectively accumulated inside cancer cells. PS are activated by specific wavelengths that cause tumor cell death by mechanisms related with oxidative stress.

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The morphological, optical, and structural changes in crystalline chiral imines derived from 2-naphthaldehyde as a result of changing the -, -, and - halogen (-) atoms are reported. Scanning electron microscopy (SEM), optical absorption, photoluminescence (PL), and powder X-ray diffraction (XRD) studies were performed. Theoretical results of optical and structural properties were calculated using the PBE1PBE hybrid functional and compared with the experimental results.

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Alzheimer's disease (AD) is a complex neurodegenerative disorder associated with the aggregation of the amyloid-beta peptide (Aβ) into large oligomers and fibrils that damage healthy brain cells. The predominant peptide fragments in the plaques are mainly formed by the Aβ and Aβ peptides, albeit the eleven-residue Aβ segment is largely used in biological studies because it retains the neurotoxic properties of the longer Aβ peptides. Recent studies indicate that treatment with therapeutic steroid hormones reduces the progress of the disease in AD models.

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The local and condensed Fukui functions as well as the principle of hard and soft acids and bases were used to study the addition of free radicals to the exocyclic and endocyclic double bonds of seven monocyclic monoterpenes of formula CH. The results obtained showed that, in general, the most reactive double bond was the one with the most substituents on the double-bonded carbon atoms, and that the reaction of a double bond with an electrophile is a soft-soft interaction. The effects of substituents on the double-bonded carbon atoms and the stabilization of the monoterpenes were interpreted by invoking hyperconjugated structures, which led us to propose a simple rule: the larger the value of the Fukui function for the double bond, the greater the hyperconjugative stabilization and the susceptibility of the double bond to electrophilic attack.

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Vanadium(IV/V) compounds have been studied as possible metallopharmaceutical drugs against diabetes mellitus. However, mechanisms of action and toxicological threshold have been tackled poorly so far. In this paper, our purposes were to evaluate the metabolic activity on dyslipidemia and dysglycemia, insulin signaling in liver and adipose tissue, and toxicology of the title compound.

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This work presents a thermochemical study of two derivatives of phthalimide: the isomers 3-nitrophthalimide and 4-nitrophthalimide. The enthalpies of formation for these compounds in the solid phase were obtained by combustion calorimetry. Using ths thermogravimetry technique, the enthalpies of vaporization were obtained.

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Alzheimer's disease (AD) is a neurodegenerative disorder caused by the aggregation of the amyloid-beta peptide (Aβ) in senile plaques and cerebral vasculature. The Aβ fraction has shown the most toxicity; its neurotoxic mechanisms are associated with the generation of oxidative stress and reactive astrogliosis that induce neuronal death and memory impairment. Studies indicate that pharmacological treatment with flavonoids reduces the rate of AD, in particular, it has been shown that antioxidants are compounds that could interact with this peptide due to their antioxidant proprieties.

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Transition-metal complexes bearing fluorinated phosphane and thiolate ligands has been an area of study in recent years and the chemical context of the current work is related to the metal-assisted functionalization of fluorinated derivatives. The cis and trans isomers of the square-planar complex bis[(pentafluorophenyl)diphenylphosphane-κP]bis(2,3,5,6-tetrafluorobenzenethiolato-κS)platinum(II), [Pt(C6HF4S)2{P(C6H5)2(C6F5)}2], have been crystallized from a single chromatographic fraction and characterized by X-ray diffraction analysis. The stabilization of the cis isomer results from weak intramolecular π-stacking interactions and possibly from the formation of a C-F.

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Most of the naturally occurring steroidal sapogenins (C-23 non-substituted frameworks), possess an R configuration at the spiro C-22 center. Their C-22 epimers have become important targets in biological research. This paper describes a procedure to obtain 22S-spirostans from 22R-sapogenins and pseudosapogenin skeletons, without affecting the chirality at either C-25 or C-20.

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A combined theoretical and experimental study on the structure, infrared, UV-Vis and 1H NMR data of trans-2-(m-cyanostyryl)pyridine, trans-2-[3-methyl-(m-cyanostyryl)]pyridine and trans-4-(m-cyanostyryl)pyridine is presented. The synthesis was carried out with an efficient Knoevenagel condensation using green chemistry conditions. Theoretical geometry optimizations and their IR spectra were carried out using the Density Functional Theory (DFT) in both gas and solution phases.

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This study examined absorption properties of 2-styrylpyridine, trans-2-(m-cyanostyryl)pyridine, trans-2-[3-methyl-(m-cyanostyryl)]pyridine, and trans-4-(m-cyanostyryl)pyridine compounds based on theoretical UV/Vis spectra, with comparisons between time-dependent density functional theory (TD-DFT) using B3LYP, PBE0, and LC-ωPBE functionals. Basis sets 6-31G(d), 6-31G(d,p), 6-31+G(d,p), and 6-311+G(d,p) were tested to compare molecular orbital energy values, gap energies, and maxima absorption wavelengths. UV/Vis spectra were calculated from fully optimized geometry in B3LYP/6-311+G(d,p) in gas phase and using the IEFPCM model.

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We present a molecular docking study aimed to identify the binding site of protonated aminopyridines for the blocking of voltage dependent K(+) channels. Several active aminopyridines are considered: 2-aminopyridine, 3-aminopyridine, 4-aminopyridine, 3,4-diaminopyridine, and 4-aminoquinoleine. We apply the AutoDock force field with a lamarckian genetic algorithm, using atomic charges for the ligands derived from the electrostatic potential obtained at the B3LYP/cc-pVDZ level.

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