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1.
Mar Drugs ; 22(3)2024 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-38535438

RESUMEN

An unreported prenylated indole derivative hydroxytakakiamide (4) was isolated, together with the previously described ergosterol (1), ergosterol acetate (2), and (3R)-3-(1H-indol-3-ylmethyl)-3, 4-dihydro-1H-1,4-benzodiazepine-2,5-dione (3), from the column fractions of the crude ethyl acetate extract of the culture of a marine sponge-associated fungus, Aspergillus fischeri MMERU 23. The structure of 4 was elucidated by the interpretation of 1D and 2D NMR spectral data and high-resolution mass spectrum. The absolute configuration of the stereogenic carbon in 3 was proposed to be the same as those of the co-occurring congeners on the basis of their biogenetic consideration and was supported by the comparison of its sign of optical rotation with those of its steroisomers. The crude ethyl acetate extract and 2 were evaluated, together with acetylaszonalenin (5) and helvolic acid (6), which were previously isolated from the same extract, for the in vivo antinociceptive activity in the mice model. The crude ethyl acetate extract exhibited antinociceptive activity in the acetic acid-induced writhing and formalin tests, while 2, 5, and 6 displayed the effects in the late phase of the formalin test. On the other hand, neither the crude ethyl acetate extract nor 2, 5, and 6 affected the motor performance of mice in both open-field and rotarod tests. Additionally, docking studies of 2, 5, and 6 were performed with 5-lipoxygenase (5-LOX) and phosphodiesterase (PDE) enzymes, PDE4 and PDE7, which are directly related to pain and inflammatory processes. Molecular docking showed that 6 has low affinity energy to PDE4 and PDE7 targets while retaining high affinity to 5-LOX. On the other hand, while 2 did not display any hydrogen bond interactions in any of its complexes, it achieved overall better energy values than 6 on the three antinociceptive targets. On the other hand, 5 has the best energy profile of all the docked compounds and was able to reproduce the crystallographic interactions of the 5-LOX complex.


Asunto(s)
Acetatos , Aspergillus , Hongos , Ácido Fusídico/análogos & derivados , Poríferos , Animales , Ratones , Simulación del Acoplamiento Molecular , Ácido Acético , Ergosterol , Analgésicos
2.
Chem Biodivers ; 21(7): e202400594, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38651347

RESUMEN

The present study describes the seasonal and circadian variations of the major compounds from Lippia alba leaves. SPSS was used to identify, quantify, and associate the variations in the secondary metabolites of this species through HPLC/DAD analysis of the leaves hydroethanolic extracts of six selected L. alba specimens. For the circadian study, the samples were collected at four different daily hours in each year's season. For the seasonal study, the samples were collected monthly from the same individuals for two consecutive years (2018 and 2019). These samples were analyzed and quantified using a validated HPLC method for flavonoids, iridoids, and phenyl ethanoid glycoside. Mussaenoside, acteoside, and tricin-7-O-diglucuronide showed a moderate positive correlation between their biosynthesis and the precipitation index, while epi-loganin had a moderate negative correlation. Acteoside showed a moderate positive correlation between the minimum registered temperature and its production. Compared with previous studies, a drastic reduction (about 95 %) in the production of tricin-7-O-diglucuronide compared with previous study and this difference could be attributed to the plant's aging. Thus, the data demonstrated that lower temperatures and high rainfall could favor the production of the major L. alba active compounds (acteoside and tricin-7-O-diglucuronide) and that older plants harm their production.


Asunto(s)
Lippia , Hojas de la Planta , Estaciones del Año , Hojas de la Planta/química , Hojas de la Planta/metabolismo , Lippia/química , Lippia/metabolismo , Cromatografía Líquida de Alta Presión , Extractos Vegetales/química , Extractos Vegetales/metabolismo
3.
Int J Mol Sci ; 25(5)2024 Feb 22.
Artículo en Inglés | MEDLINE | ID: mdl-38473794

RESUMEN

MicroRNAs (miRs) act as important post-transcriptional regulators of gene expression in glial cells and have been shown to be involved in the pathogenesis of neurodegenerative diseases, including Alzheimer's disease (AD). Here, we investigated the effects of agathisflavone, a biflavonoid purified from the leaves of Cenostigma pyramidale (Tul.), on modulating the expression of miRs and inflammatory mediators in activated microglia. C20 human microglia were exposed to oligomers of the ß-amyloid peptide (Aß, 500 nM) for 4 h or to lipopolysaccharide (LPS, 1 µg/mL) for 24 h and then treated or not with agathisflavone (1 µM) for 24 h. We observed that ß-amyloid and LPS activated microglia to an inflammatory state, with increased expression of miR-146a, miR-155, IL1-ß, IL-6, and NOS2. Treatment with agathisflavone resulted in a significant reduction in miR146a and miR-155 induced by LPS or Aß, as well as inflammatory cytokines IL1-ß, IL-6, and NOS2. In cells stimulated with Aß, there was an increase in p-STAT3 expression that was reduced by agathisflavone treatment. These data identify a role for miRs in the anti-inflammatory effect of agathisflavone on microglia in models of neuroinflammation and AD.


Asunto(s)
Enfermedad de Alzheimer , Biflavonoides , MicroARNs , Humanos , Biflavonoides/farmacología , Microglía/metabolismo , Interleucina-6/metabolismo , Lipopolisacáridos/farmacología , Enfermedad de Alzheimer/metabolismo , Péptidos beta-Amiloides/metabolismo , Citocinas/metabolismo , MicroARNs/genética , Factor de Transcripción STAT3/metabolismo
4.
Nutr Health ; 28(3): 401-415, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35014893

RESUMEN

Background: Green tea, obtained from the plant Camellis sinensis, is one of the oldest drinks in the world and contains numerous bioactive compounds. Studies have demonstrated the efficacy of green tea in preventing obesity and cardiovascular diseases that may be related to the reduction of lipid levels. Aim: This study aimed to evidence, through a systematic review, the therapeutic potential of green tea on the lipid profile in preclinical studies in obese animals and clinical studies in obese individuals. Methods: This systematic review follows the recommendations of the preferred report items for systematic reviews and meta-analyses. The electronic databases, PubMed (Medline), Science Direct, Scopus, and Web of Science were consulted. Articles from January 2009 to December 2019 were selected. Results: This search resulted in twenty-nine articles were included cirtically reviewed. In experimental studies, green tea administration has been shown to reduce total cholesterol, triglycerides and low-density lipoprotein cholesterol in animals exposed to obesity-inducing diet. In humans' studies green tea was not shown to be effective for obese lipid control. Because supplementation with green tea extract reduced total cholesterol, triglycerides, low-density lipoprotein for three months at a specific dose. Conclusion: Therefore, green tea appears to act as a protective agent for dyslipidemia in obesity-induced animals. In human studies, green tea has not been shown to be effective in controlling obese lipids.


Asunto(s)
Obesidad , , Animales , Colesterol , Humanos , Lipoproteínas LDL/uso terapéutico , Obesidad/tratamiento farmacológico , Extractos Vegetales/farmacología , Extractos Vegetales/uso terapéutico , Triglicéridos
5.
Molecules ; 27(24)2022 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-36557799

RESUMEN

Neutral (n) and zwitterionic (z) forms of cysteine monomers are combined in this work to extensively explore the potential energy surfaces for the formation of cysteine dimers in aqueous environments represented by a continuum. A simulated annealing search followed by optimization and characterization of the candidate structures afforded a total of 746 structurally different dimers held together via 80 different types of intermolecular contacts in 2894 individual non-covalent interactions as concluded from Natural Bond Orbitals (NBO), Quantum Theory of Atoms in Molecules (QTAIM) and Non-Covalent Interactions (NCI) analyses. This large pool of interaction possibilities includes the traditional primary hydrogen bonds and salt bridges which actually dictate the structures of the dimers, as well as the less common secondary hydrogen bonds, exotic X⋯Y (X = C, N, O, S) contacts, and H⋯H dihydrogen bonds. These interactions are not homogeneous but have rather complex distributions of strengths, interfragment distances and overall stabilities. Judging by their Gibbs bonding energies, most of the structures located here are suitable for experimental detection at room conditions.


Asunto(s)
Cisteína , Teoría Cuántica , Polímeros , Enlace de Hidrógeno
6.
J Cell Physiol ; 236(7): 5022-5035, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-33368262

RESUMEN

Glioblastoma is the most lethal tumor of the central nervous system, presenting a very poor prognostic, with a survival around 16 months. The interaction of mesenchymal stem cells and tumor cells has been studied, showing a bias in their role favoring or going against aggressiveness. Natural products such as flavonoids have showed their anticancer properties and the synergic potential with the activation of microenvironment cells to inhibit tumor progression. Agathisflavone is a flavonoid studied in neurodegenerative diseases and cancer. The present study investigated the effect of flavonoid in the viability of heterogeneous glioblastoma (GBM) cells considering a coculture or conditioned medium of mesenchymal stem cells (MSCs) effect, as well as the dose-dependent effect of this flavonoid in tumor migration and differentiation via STAT3. Agathisflavone (3-10 µM) induced dose-dependent toxicity to GL-15 and U373 human GBM cells, since 24 h after treatments. It was not toxic to human MSC but modified the pattern of interaction with GBM cells. Agathisflavone also inhibited migration and increased differentiation of human GBM cells, associated with the reduction on the expression of STAT3. These results demonstrate that the flavonoid agathisflavone had a direct anti-glioma effect. However, could be observed its effect in MSCs response that may have an impact in controlling GBM growth and aggressiveness, an important factor to consider for new therapies.


Asunto(s)
Antineoplásicos/farmacología , Biflavonoides/farmacología , Neoplasias Encefálicas/tratamiento farmacológico , Glioblastoma/tratamiento farmacológico , Células Madre Mesenquimatosas/metabolismo , Neoplasias Encefálicas/patología , Diferenciación Celular/efectos de los fármacos , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Técnicas de Cocultivo , Medios de Cultivo Condicionados/farmacología , Glioblastoma/patología , Humanos , Factor de Transcripción STAT3/metabolismo
7.
Chemphyschem ; 22(23): 2401-2412, 2021 12 03.
Artículo en Inglés | MEDLINE | ID: mdl-34554628

RESUMEN

High level quantum mechanical computations and extensive stochastic searches of the potential energy surfaces of the Alanine dimers uncover rich and complex structural and interaction landscapes. A total of 416 strongly bound (up 13.4 kcal mol-1 binding energies at the DLPNO-CCSD(T)/6-311++G(d,p) level corrected by the basis set superposition error and by the zero point vibrational energies over B3LYP-D3 geometries), close energy equilibrium structures were located, bonded via 32 specific types of intermolecular contacts including Y⋅⋅⋅H-X primary and Y⋅⋅⋅H-C secondary hydrogen bonds, H⋅⋅⋅H dihydrogen contacts, and non conventional anti-electrostatic Y δ-⋯ X δ- interactions. The putative global minimum is triply degenerate, corresponding to the structure of the common dimer of a carboxylic acid. All quantum descriptors of chemical bonding point to a multitude of weak individual interactions within each dimer, whose cumulative effect results in large binding energies and in an attractive fluxional wall of non-covalent interactions in the interstitial region between the monomers.

8.
Molecules ; 26(4)2021 Feb 18.
Artículo en Inglés | MEDLINE | ID: mdl-33670791

RESUMEN

Betulinic acid (BA, 3ß-hydroxy-lup-20(29)-en-28-oic acid) is a pentacyclic triterpene acid present predominantly in Betula ssp. (Betulaceae) and is also widely spread in many species belonging to different plant families. BA presents a wide spectrum of remarkable pharmacological properties, such as cytotoxic, anti-HIV, anti-inflammatory, antidiabetic and antimicrobial activities, including antiprotozoal effects. The present review first describes the sources of BA and discusses the chemical strategies to produce this molecule starting from betulin, its natural precursor. Next, the antiprotozoal properties of BA are briefly discussed and the chemical strategies for the synthesis of analogues displaying antiplasmodial, antileishmanial and antitrypanosomal activities are systematically presented. The antiplasmodial activity described for BA was moderate, nevertheless, some C-3 position acylated analogues showed an improvement of this activity and the hybrid models-with artesunic acid-showed the most interesting properties. Some analogues also presented more intense antileishmanial activities compared with BA, and, in addition to these, heterocycles fused to C-2/C-3 positions and amide derivatives were the most promising analogues. Regarding the antitrypanosomal activity, some interesting antitrypanosomal derivatives were prepared by amide formation at the C-28 carboxylic group of the lupane skeleton. Considering that BA can be produced either by isolation of different plant extracts or by chemical transformation of betulin, easily obtained from Betula ssp., it could be said that BA is a molecule of great interest as a starting material for the synthesis of novel antiprotozoal agents.


Asunto(s)
Antiprotozoarios/síntesis química , Antiprotozoarios/farmacología , Triterpenos Pentacíclicos/síntesis química , Triterpenos Pentacíclicos/farmacología , Antiprotozoarios/química , Modelos Moleculares , Triterpenos Pentacíclicos/química , Triterpenos/química , Ácido Betulínico
9.
Pharmacol Res ; 159: 104997, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32534098

RESUMEN

Myelin loss is the hallmark of the demyelinating disease multiple sclerosis (MS) and plays a significant role in multiple neurodegenerative diseases. A common factor in all neuropathologies is the central role of microglia, the intrinsic immune cells of the central nervous system (CNS). Microglia are activated in pathology and can have both pro- and anti-inflammatory functions. Here, we examined the effects of the flavonoid agathisflavone on microglia and remyelination in the cerebellar slice model following lysolecithin induced demyelination. Notably, agathisflavone enhances remyelination and alters microglial activation state, as determined by their morphology and cytokine profile. Furthermore, these effects of agathisflavone on remyelination and microglial activation were inhibited by blockade of estrogen receptor α. Thus, our results identify agathisflavone as a novel compound that may act via ER to regulate microglial activation and enhance remyelination and repair.


Asunto(s)
Antiinflamatorios/farmacología , Biflavonoides/farmacología , Cerebelo/efectos de los fármacos , Microglía/efectos de los fármacos , Vaina de Mielina/metabolismo , Neuroinmunomodulación/efectos de los fármacos , Oligodendroglía/efectos de los fármacos , Remielinización/efectos de los fármacos , Animales , Diferenciación Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Cerebelo/inmunología , Cerebelo/metabolismo , Cerebelo/patología , Citocinas/metabolismo , Receptor alfa de Estrógeno/efectos de los fármacos , Receptor alfa de Estrógeno/metabolismo , Femenino , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Lisofosfatidilcolinas/toxicidad , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Microglía/inmunología , Microglía/metabolismo , Microglía/patología , Oligodendroglía/inmunología , Oligodendroglía/metabolismo , Oligodendroglía/patología , Fenotipo , Técnicas de Cultivo de Tejidos
10.
Int J Mol Sci ; 21(14)2020 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-32659952

RESUMEN

Diabetic neuropathy is a frequent complication of diabetes. Symptoms include neuropathic pain and sensory alterations-no effective treatments are currently available. This work characterized the therapeutic effect of bergenin in a mouse (C57/BL6) model of streptozotocin-induced painful diabetic neuropathy. Nociceptive thresholds were assessed by the von Frey test. Cytokines, antioxidant genes, and oxidative stress markers were measured in nervous tissues by ELISA, RT-qPCR, and biochemical analyses. Single (3.125-25 mg/kg) or multiple (25 mg/kg; twice a day for 14 days) treatments with bergenin reduced the behavioral signs of diabetic neuropathy in mice. Bergenin reduced both nitric oxide (NO) production in vitro and malondialdehyde (MDA)/nitrite amounts in vivo. These antioxidant properties can be attributed to the modulation of gene expression by the downregulation of inducible nitric oxide synthase (iNOS) and upregulation of glutathione peroxidase and Nrf2 in the nervous system. Bergenin also modulated the pro- and anti-inflammatory cytokines production in neuropathic mice. The long-lasting antinociceptive effect induced by bergenin in neuropathic mice, was associated with a shift of the cytokine balance toward anti-inflammatory predominance and upregulation of antioxidant pathways, favoring the reestablishment of redox and immune homeostasis in the nervous system. These results point to the therapeutic potential of bergenin in the treatment of painful diabetic neuropathy.


Asunto(s)
Benzopiranos/farmacología , Homeostasis/efectos de los fármacos , Sistema Inmunológico/efectos de los fármacos , Sistema Nervioso/efectos de los fármacos , Neuralgia/tratamiento farmacológico , Oxidación-Reducción/efectos de los fármacos , Animales , Antiinflamatorios/farmacología , Antioxidantes/metabolismo , Citocinas/metabolismo , Diabetes Mellitus Experimental/inducido químicamente , Diabetes Mellitus Experimental/complicaciones , Diabetes Mellitus Experimental/metabolismo , Neuropatías Diabéticas/inducido químicamente , Neuropatías Diabéticas/complicaciones , Neuropatías Diabéticas/metabolismo , Glutatión Peroxidasa/metabolismo , Sistema Inmunológico/metabolismo , Masculino , Malondialdehído/metabolismo , Ratones , Ratones Endogámicos C57BL , Factor 2 Relacionado con NF-E2/metabolismo , Sistema Nervioso/metabolismo , Neuralgia/etiología , Neuralgia/metabolismo , Óxido Nítrico/metabolismo , Óxido Nítrico Sintasa de Tipo II/metabolismo , Estrés Oxidativo/efectos de los fármacos , Estreptozocina/farmacología
11.
Molecules ; 25(20)2020 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-33092066

RESUMEN

Passiflora alata or passion fruit is a native flowering plant from Amazon, geographically spread from Peru to Brazil. The plant has long been used in folks medicine for its pharmacological properties and is included in the Brazilian Pharmacopoeia since 1929. The aim of this study was to evaluate the potential cytotoxic and antitumor activities of Passiflora alata leaf extract (PaLE) in S180-tumor bearing mice. The percentage of cell proliferation inhibition (% CPI) and IC50 in relation to 4 tumor cell lines were determined in PC3, K-562, HepG2 and S180 cell lines using the MTT assay. PaLE showed a CPI > 75% and greater potency (IC50 < 30 µg/mL) against PC3 and S180 cell lines. PaLE showed antitumor activity in treatments intraperitoneally (36.75% and 44.99% at doses of 100 and 150 mg/kg/day, respectively). Toxicological changes were shown in the reduced body mass associated with reduced food consumption, increased spleen mass associated with histopathological increase in the white pulp of the spleen and increased number of total leukocytes with changes in the percentage relationship between lymphocytes and neutrophils. Our outcomes corroborate the conclusion that PaLE has antitumor activity in vitro and in vivo with low toxicity.


Asunto(s)
Flavonoides/farmacología , Neoplasias/tratamiento farmacológico , Passiflora/química , Extractos Vegetales/farmacología , Animales , Antineoplásicos/química , Antineoplásicos/farmacología , Brasil , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Flavonoides/química , Xenoinjertos , Humanos , Ratones , Neoplasias/patología , Perú , Extractos Vegetales/química , Hojas de la Planta/química
12.
Parasitology ; 145(14): 1884-1889, 2018 12.
Artículo en Inglés | MEDLINE | ID: mdl-29781423

RESUMEN

This study assessed the anthelmintic activity of plant-derived compounds against gastrointestinal nematodes of goats using the egg hatch and larval motility assays. The compounds tested were saponins (digitonin and aescin) and their respective sapogenins (aglycones), hecogenin acetate and flavonoids (catechin, hesperidin, isocordoin and a mixture of isocordoin and cordoin). Additionally, cytotoxicity of active substances was analysed on Vero cell through 3-4,5-dimethylthiazol-2-yl,2,5diphenyltetrazolium bromide (MTT) and propidium iodide (PI) tests. Significant reduction on the egg hatching (P 90%). Nevertheless, higher cytotoxicity was observed in the MTT assay, with IC50 of 0.20 mg mL-1 (aescin) and 0.0074 mg mL-1 (digitonin). Aescin and digitonin have a pronounced in vitro anthelmintic effect and the glycone portion of these saponins plays an important role in this activity.


Asunto(s)
Antinematodos/farmacología , Flavonoides/farmacología , Cabras/parasitología , Nematodos/efectos de los fármacos , Oocitos/efectos de los fármacos , Saponinas/farmacología , Animales , Supervivencia Celular/efectos de los fármacos , Chlorocebus aethiops , Digitonina/farmacología , Tracto Gastrointestinal/parasitología , Concentración 50 Inhibidora , Larva/efectos de los fármacos , Compuestos de Espiro/farmacología , Esteroides/farmacología , Células Vero
13.
Regul Toxicol Pharmacol ; 94: 75-82, 2018 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-29339246

RESUMEN

Neoflavonoids, which are classified as 4-arylcoumarin (neoflavone), 3,4-dihydro-4-arylcoumarin and neoflavene, have been the subject of a number of studies with respect to their therapeutic potential and, despite promising in vitro, ex vivo and in vivo pharmacological activities, there is a lack of studies demonstrating their toxicological properties. Therefore, this study aims to evaluate the acute (14 days) and repeated-dose (28 days) toxicity of synthetic neoflavonoid 7-acetoxy-4-aryl-3,4-dihydrocoumarin in Swiss mice through parameters related to changes in body weight, food and water intake, hematological and biochemical parameters. Toxicity studies using acute doses (300 and 2000 mg/kg) and repeated doses (250, 500 and 1000 mg/kg) orally were carried out as per Organization for Economic Co-operation and Development (OECD) guidelines 423 and 407, respectively. Based on the results of this study, treatment with 7-acetoxy-4-aryl-3,4-dihydrocoumarin was found to not cause clinical adverse symptoms and mortality in any animal used in the acute and repeated-dose toxicity study. In addition, no significant changes were observed in body weight and internal organs, food and water intake, hematological and biochemical parameters, compared to control group. Therefore, these results provide an initial understanding regarding the toxicity profile of 7-acetoxy-4-aryl-3,4-dihydrocoumarin, which can be considered a neoflavonoid with toxicity seen at doses higher than 2000 mg/kg in Swiss mice.


Asunto(s)
Cumarinas/toxicidad , Animales , Artemia/efectos de los fármacos , Femenino , Masculino , Ratones , Pruebas de Toxicidad Aguda , Pruebas de Toxicidad Subaguda
14.
An Acad Bras Cienc ; 89(3): 1369-1379, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28813102

RESUMEN

Natural steroids and triterpenes such as b-sitosterol, stigmasterol, lupeol, ursolic and betulinic acids were transformed into its hexanoic and oleic esters, to evaluate the influence of chemical modification towards the cytotoxic activities against tumor cells. The derivatives were evaluated against five tumor cell lines [OVCAR-8 (ovarian carcinoma); SF-295 (glioblastoma); HCT-116 (colon adenocarcinoma); HL-60 (leukemia); and PC-3 (prostate carcinoma)] and the results showed only betulinic acid hexyl ester exhibits cytotoxic potential activity.


Asunto(s)
Antineoplásicos/farmacología , Fabaceae/química , Lamiaceae/química , Triterpenos Pentacíclicos/farmacología , Triterpenos/farmacología , Antineoplásicos/química , Antineoplásicos/aislamiento & purificación , Línea Celular Tumoral , Ensayos de Selección de Medicamentos Antitumorales , Ésteres , Fabaceae/clasificación , Humanos , Concentración 50 Inhibidora , Lamiaceae/clasificación , Triterpenos Pentacíclicos/química , Triterpenos Pentacíclicos/aislamiento & purificación , Triterpenos/química , Triterpenos/aislamiento & purificación , Ácido Betulínico , Ácido Ursólico
15.
Phys Chem Chem Phys ; 18(3): 1537-50, 2016 Jan 21.
Artículo en Inglés | MEDLINE | ID: mdl-26670708

RESUMEN

Hartree-Fock (HF) and second order perturbation theory (MP2) calculations within the scalar and full relativistic frames were carried out in order to determine the equilibrium geometries and interaction energies between cationic methylmercury (CH3Hg(+)) and up to three water molecules. A total of nine structures were obtained. Bonding properties were analyzed using the Quantum Theory of Atoms In Molecules (QTAIM). The analyses of the topology of electron densities reveal that all structures exhibit a partially covalent HgO interaction between methylmercury and one water molecule. Consideration of additional water molecules suggests that they solvate the (CH3HgOH2)(+) unit. Nuclear magnetic shielding constants σ((199)Hg), σ((13)C) and σ((17)O), as well as indirect spin-spin coupling constants J((199)Hg-(13)C), J((199)Hg-(17)O) and J((13)C-(17)O), were calculated for each one of the geometries. Thermodynamic stability and the values of NMR constants correlate with the ability of the system to directly coordinate oxygen atoms of water molecules to the mercury atom in methylmercury and with the formation of hydrogen bonds among solvating water molecules. Relativistic effects account for 11% on σ((13)C) and 14% on σ((17)O), which is due to the presence of Hg (heavy atom on light atom, HALA effect), while the relativistic effects on σ((199)Hg) are close to 50% (heavy atom on heavy atom itself, HAHA effect). J-coupling constants are highly influenced by relativity when mercury is involved as in J((199)Hg-(13)C) and J((199)Hg-(17)O). On the other hand, our results show that the values of NMR constants for carbon and oxygen, atoms which are connected through mercury (C-HgO), are highly correlated and are greatly influenced by the presence of water molecules. Water molecules introduce additional electronic effects to the relativistic effects due to the mercury atom.

16.
Pharm Biol ; 53(4): 582-7, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25489636

RESUMEN

CONTEXT: The labdenic diterpene labd-8(17)-en-15-oic acid (labd-8) isolated from a methanolic extract of Moldenhawera nutans Queiroz & Alkin (Leguminosae) has hypotensive and tachycardiac properties in normotensive rats. A part of the hypotensive effect was due to a reduction in the sympathetic nerve drive to vessels, an event admittedly enhanced in spontaneously hypertensive rats (SHRs). OBJECTIVES: We assessed whether the cardiovascular effects induced by labd-8 could be enhanced in SHRs. MATERIALS AND METHODS: For in vivo experiments, arterial and venous catheters were implanted under anesthesia for blood pressure recording and drug administration, respectively. For in vitro experiments, thoracic aorta rings were suspended in organ baths containing warm (37 °C) perfusion medium that was continuously bubbled with carbogen. RESULTS: Intravenous injection of labd-8 (1, 3, 5, and 10 mg/kg) induced similar dose-dependent hypotension and tachycardia in both SHRs and Wistar-Kyoto rats (WKY). In SHRs, only the tachycardia response to labd-8 was significantly reduced by pretreatment with methylatropine or propranolol. However, both cardiovascular effects of labd-8 were reduced by hexamethonium while remained unchanged by l-NAME. In isolated aortic preparations from SHRs, labd-8 (1-1000 µg/mL) relaxed potassium-induced contractions with an IC50 (geometric mean [95% confidence interval]) value (536.5 [441.0-631.9] µg/mL) significantly greater than that (157.6 [99.1-250.5] µg/mL) obtained in preparations from WKY rats. CONCLUSION: In SHRs, the hypotension induced by labd-8 is associated with a reflex tachycardia and seems mediated partly through withdrawal of sympathetic vasomotor tone and partly through an active vasorelaxation. Its magnitude was not enhanced when compared with WKY rats likely because of impaired vasorelaxant effects of labd-8 in preparations from SHRs.


Asunto(s)
Antihipertensivos/uso terapéutico , Diterpenos/uso terapéutico , Fabaceae/química , Hipertensión/tratamiento farmacológico , Extractos Vegetales/uso terapéutico , Taquicardia/inducido químicamente , Animales , Antihipertensivos/administración & dosificación , Antihipertensivos/farmacología , Sistema Nervioso Autónomo/efectos de los fármacos , Diterpenos/administración & dosificación , Diterpenos/aislamiento & purificación , Hipertensión/complicaciones , Hipertensión/fisiopatología , Extractos Vegetales/administración & dosificación , Extractos Vegetales/aislamiento & purificación , Tallos de la Planta/química , Ratas Endogámicas SHR , Ratas Endogámicas WKY , Especificidad de la Especie , Taquicardia/etiología
17.
BMC Chem ; 18(1): 13, 2024 Jan 13.
Artículo en Inglés | MEDLINE | ID: mdl-38218834

RESUMEN

This study describes methodologies for extracting and isolating bergenin, a C-glucoside of 4-O-methylgallic acid found in some plants and it presents various in vitro and in vivo biological activities. Bergenin was previously obtained from the Pelthophorum dubim (Fabaceae) roots with a good yield. Conventional chromatographic procedures of the CHCl3 soluble fraction of the MeOH extract gave 3.62% of this glucoside. An HPLC/DAD method was also developed and validated for bergenin and its precursor, gallic acid quantifications. Microwave extractions with different solvents were tested to optimize the extraction of bergenin, varying the temperature and time. MAE (Microwave Assisted Extraction) was more efficient than conventional extraction procedures, giving a higher yield of bergenin per root mass (0.45% vs. 0.0839%). Molecularly imprinted polymer (MIP) and non-imprinted polymer (NIP) based on bergenin as the template molecule, methacrylic acid, and ethylene glycol dimethacrylate were synthesized and characterized by FTIR and SEM (Scanning Electron Microscopy). Bergenin adsorption experiments using MIP and NIP followed by molecular imprinted solid phase extraction (MISPE) showed that MIP had a higher selectivity for bergenin than NIP. A dendrochronological study using the proposed method for detection and quantification of gallic acid and bergenin in five P. dubium growth rings of a 31-year-old heartwood and in the phelloderm and barks indicated that bergenin was more abundant in the 11-14th growth rings of the heartwood and decreased from the heartwood to the barks.

18.
Phys Chem Chem Phys ; 15(9): 3203-11, 2013 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-23344174

RESUMEN

We present an exhaustive stochastic search of the quantum conformational spaces of the (CH(3)O)(2)PO(2)(-) + nH(2)O (n = 1,2,3) systems. We uncover structural, conformational and energetic features of the problem. As in the isolated species, clusters containing the gauche-gauche (gg) conformation of dimethylphosphate (DMP(-)) are energetically preferred, however, contributions from hydrated gauche-anti (ga) and anti-anti (aa) monomers cannot be neglected because such structures are quite common and because they are close in energy to those containing the gg monomer. At least seven distinct types of O∙∙∙H-O-H contacts lead to DMP(-) ↔ water interactions that are always stabilizing, but not strong enough to induce significant changes in the geometries of either DMP(-) or water units. Our results lead us to postulate DMP(-) to be a suitable model to study explicit and detailed aspects of microsolvation of cell membranes.


Asunto(s)
Membrana Celular/química , Modelos Moleculares , Compuestos Organofosforados/química , Solventes/química , Agua/química , Conformación Molecular , Estereoisomerismo , Procesos Estocásticos , Termodinámica
19.
J Chem Phys ; 139(4): 044310, 2013 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-23901983

RESUMEN

In this paper we report the geometries and properties of 38 distinct geometrical motifs located on the B3LYP/6-31+G(d), MP2/6-311++G(d, p) potential energy surfaces of the water heptamer. Binding energies of up to 45 kcal/mol are calculated. All motifs fall within 10 kcal/mol of the most stable conformation, with at least 13 structural patterns located no more than 3 kcal/mol above, leading to a very complex potential energy surface, populated by a multitude of motifs each one allowing large numbers of conformations. Cluster stability does not seem to be correlated with the number of hydrogen bonds. Compact structures are energetically favored by electronic energies with zero-point energy corrections, while more open structures are preferred when temperature and entropy are accounted for. The molecular interactions holding the clusters as discrete units lead to large binding energies but are not strong enough to cause significant changes in the geometries of the interacting monomers. Our results indicate that bonding in the water heptamers can be considered as largely non-shared interactions with contributions from intermediate character of increasing covalency.


Asunto(s)
Modelos Moleculares , Termodinámica , Agua , Enlace de Hidrógeno , Agua/química
20.
Biol Res ; 46(3): 231-8, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24346069

RESUMEN

This study describes the isolation and identification of apigenin-7-O-ghicopyranoside, a flavonoid isolated from the flowers of Bellis perennis L., Asteraceae, an species with a broad spectrum of biological activities. The in vitro antioxidant activity and the inhibition of the enzyme acetylcholinesterase were evaluated. The flavonoid showed strong in vitro antioxidant potential, because of the capacity of removal of hydroxyl radicals and nitric oxide, and also prevented the formation of thiobarbituric acid-reactive substances. These parameters were inhibited at the highest concentration of ApG at rates of 77.7%, 72% and 73.4%, respectively, in addition to inhibiting acetylcholinesterase, suggesting potential use in the treatment of neurodegenerative diseases.


Asunto(s)
Antioxidantes/farmacología , Asteraceae/química , Inhibidores de la Colinesterasa/farmacología , Flores/química , Extractos Vegetales/farmacología , Acetilcolinesterasa/efectos de los fármacos , Asteraceae/clasificación , Peroxidación de Lípido/efectos de los fármacos , Extractos Vegetales/aislamiento & purificación
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