Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 41
Filter
Add more filters










Publication year range
1.
Plants (Basel) ; 13(12)2024 Jun 14.
Article in English | MEDLINE | ID: mdl-38931078

ABSTRACT

Blueberries (Vaccinium corymbosum L.) are cultivated worldwide and are among the best dietary sources of bioactive compounds with beneficial health effects. This study aimed to investigate the components of Peruvian blueberry using high-performance liquid chromatography coupled to electrospray ionization and quadrupole time-of-flight mass spectrometry (HPLC-ESI-QTOF-MS/MS), identifying 11 compounds. Furthermore, we assessed in vitro the antioxidant activity and in vivo the antidepressant effect using a rat model and protective effect on lipid peroxidation (in the serum, brain, liver, and stomach). We also conducted molecular docking simulations with proteins involved in oxidative stress and depression for the identified compounds. Antioxidant activity was assessed by measuring total phenolic and flavonoid contents, as well as using 1,1-diphenyl-2-picrylhydrazin (DPPH), 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic) acid (ABTS•+), and ferric-reducing antioxidant power (FRAP) assays. Peruvian blueberries demonstrated higher antioxidant activity than Vaccinium corymbosum fruits from Chile, Brazil, the United States, Turkey, Portugal, and China. The results showed that oral administration of Peruvian blueberries (10 and 20 mg/kg) for 28 days significantly (p < 0.001) increased swimming and reduced immobility in the forced swimming test (FST). Additionally, at doses of 40 and 80 mg/kg, oxidative stress was reduced in vivo (p < 0.001) by decreasing lipid peroxidation in brain, liver, stomach, and serum. Molecular docking and absorption, distribution, metabolism, excretion, and toxicity (ADMET) predictions were performed. In the molecular docking studies, quercitrin and 3,5-di-O-caffeoylquinic acid showed the best docking scores for nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, superoxide dismutase, and xanthine oxidase; while 3,5-dicaffeoylquinic acid methyl ester and caffeoyl coumaroylquinic acid had the best docking scores for monoamine oxidase and serotonin receptor 5-HT2. In summary, our results suggest that the antidepressant and protective effects against lipid peroxidation might be related to the antioxidant activity of Peruvian Vaccinium corymbosum L.

2.
J Phys Chem A ; 128(25): 4950-4955, 2024 Jun 27.
Article in English | MEDLINE | ID: mdl-38864772

ABSTRACT

In this article, we systematically study the stability and chemical bond nature of EH4Ng+ compounds (E = Al-Tl; Ng = He-Rn) at the CCSD(T) and ωB97XD levels of theory. Thermochemical calculations obtained by exploring different dissociation pathways show that these compounds could be stable at low temperatures. In addition, studied compounds have a strong E-Ng bond, which has been characterized using different methodologies such as quantum theory of atoms in molecules (QTAIM), natural bond orbital (NBO) theory, and natural energy decomposition analysis (NEDA). Results indicate that the nature of the chemical bond is predominantly covalent, especially in the case those including the heavier gases (Ar-Rn), occurring through a charge transfer from the noble gas to the group 13 element. However, the electrostatic contribution is also important in the stabilization of this bond. This study extends the universe of group 13 molecules containing noble gas bonds beyond boron and other elements from the second period.

3.
Phys Chem Chem Phys ; 26(21): 15386-15392, 2024 May 29.
Article in English | MEDLINE | ID: mdl-38747026

ABSTRACT

Singlet fission (SF) compounds offer a promising avenue for improving the performance of solar cells. Using TD-DFT methods, anti-Kasha azulene derivatives that could carry out SF have been designed. For this purpose, substituted azulenes with a donor (-OH) and/or an acceptor group (-CN) have been systematically studied using the S2 ≥ 2T1 formula. We have found that -CN (-OH) substituents on electrophilic (nucleophilic) carbons result in improved SF properties when compared to azulene.

4.
Phys Chem Chem Phys ; 26(23): 16687-16692, 2024 Jun 12.
Article in English | MEDLINE | ID: mdl-38809129

ABSTRACT

An analysis of the thermodynamic and kinetic stability and the nature of the chemical bond in hypercoordinated compounds with the formula BeH3Ng+ (Ng = He-Rn) through high-level calculations is presented in this work. Thermochemical calculations show that, for the heavier noble gases (Ar-Rn), these systems are thermodynamically stable at room temperature; however, this stability decreases due to a weakening of the Be-H2 interaction, while the Be-Ng bond strengthens going down the periodic table. These results are complemented by Born Oppenheimer molecular dynamics simulations, in which the increasing tendency to dissociate the Be-H2 bond is evidenced. The nature of the chemical bonding depends on the analysis performed. On the one hand, the interacting quantum atoms method indicates that the covalent contribution is around 25 to 30%. On the other hand, the electron density topology indicates a covalent nature for compounds with Kr-Rn, while Hirshfeld population analysis in conjunction with Mayer's bond order establishes polar covalent behavior. The geometrical parameters and natural energy decomposition analysis (NEDA) indicate a covalent nature, allowing us to consider that the Be-Ng bond has a partially covalent character.

5.
Chemphyschem ; 25(12): e202400271, 2024 Jun 17.
Article in English | MEDLINE | ID: mdl-38530286

ABSTRACT

This study comprehensively analyzes the magnetically induced current density of polycyclic compounds labeled as "aromatic chameleons" since they can arrange their π-electrons to exhibit aromaticity in both the ground and the lowest triplet state. These compounds comprise benzenoid moieties fused to a central skeleton with 4n π-electrons and traditional magnetic descriptors are biased due to the superposition of local magnetic responses. In the S0 state, our analysis reveals that the molecular constituent fragments preserve their (anti)aromatic features in agreement with two types of resonant structures: one associated with aromatic benzenoids and the other with a central antiaromatic ring. Regarding the T1 state, a global and diatropic ring current is revealed. Our aromaticity study is complemented with advanced electronic and geometric descriptors to consider different aspects of aromaticity, particularly important in the evaluation of excited state aromaticity. Remarkably, these descriptors consistently align with the general features on the main delocalization pathways in polycyclic hydrocarbons consisting of fused 4n π-electron rings. Moreover, our study demonstrates an inverse correlation between the singlet-triplet energy difference and the antiaromatic character of the central ring in S0.

6.
ACS Omega ; 9(1): 1436-1442, 2024 Jan 09.
Article in English | MEDLINE | ID: mdl-38222592

ABSTRACT

An alternative approach for calculating aromatic stabilization energies is proposed based on transforming an (anti)aromatic ring into a fulvene isomer. This fulvenization process gives a value of 34.05 kcal·mol-1 for benzene in the singlet state and a value of -17.85 kcal·mol-1 in the triplet state. Additionally, it is possible to use experimental values (as long as they exist) for the calculation as the gas-phase formation enthalpies of benzene and fulvene, whose difference is 33.72 kcal·mol-1. On the other hand, this same approach has been evaluated on several six-membered rings, including those persubstituted, biradicals, azines, and inorganic analogues, giving results in agreement with those reported in the literature using different criteria. Additionally, it is possible to differentiate the aromaticity of the rings in polycyclic aromatic hydrocarbons according to Clar's rules. Assigning the (anti)aromatic character in various nonbenzenoid rings (neutral and charged), except for five- and seven-membered rings, is also possible. The construction of the fulvene isomers in PAHs is set such that nonaromaticity-related effects are not considered. The results show that the fulvenization approach is an effective and efficient approach that can serve as an alternative or complement to existing tools.

7.
Environ Sci Pollut Res Int ; 31(1): 657-667, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38015401

ABSTRACT

Azo dyes find applications across various sectors including food, pharmaceuticals, cosmetics, printing, and textiles. The contaminating effects of dyes on aquatic environments arise from toxic effects caused by their long-term presence in the environment, buildup in sediments, particularly in aquatic species, degradation of pollutants into mutagenic or mutagenic compounds, and low aerobic biodegradability. Therefore, we theoretically propose the first steps of the degradation of azo dyes based on the interaction of hydroperoxyl radical (•OOH) with the dye. This interaction is studied by the OC and ON mechanisms in three azo dyes: azobenzene (AB), disperse orange 3 (DO3), and disperse red 1 (DR1). Rate constants calculated at several temperatures show a preference for the OC mechanism in all the dyes with lower activation energies than the ON mechanism. The optical properties were calculated and because the dye-•OOH systems are open shell, to verify the validity of the results, a study of the spin contamination of the ground [Formula: see text] and excited states [Formula: see text] was previously performed. Most of the excited states calculated are acceptable as doublet states. The absorption spectra of the dye-•OOH systems show a decrease in the intensity of the bands compared to the isolated dyes and the appearance of a new band of the type π → π* at a longer wavelength in the visible region, achieving up to 868 nm. This demonstrates that the reaction with the •OOH radical could be a good alternative for the degradation of the azo dyes.


Subject(s)
Azo Compounds , Water Pollutants, Chemical , Azo Compounds/toxicity , Coloring Agents/toxicity , Allergens , Mutagens/toxicity , Water Pollutants, Chemical/toxicity
8.
Chem Commun (Camb) ; 60(4): 400-403, 2024 Jan 04.
Article in English | MEDLINE | ID: mdl-38079184

ABSTRACT

Collective interactions are a novel type of bond between metals and AX3 fragments with an electropositive central atom, A, and electronegative X substituents. Here, using electrostatic potential maps and state-of-the-art bonding analysis tools we have shown that collective interactions are anti-electrostatic cation⋯π-Hole or cation⋯lp-Hole interactions.

9.
Angew Chem Int Ed Engl ; 63(5): e202317848, 2024 Jan 25.
Article in English | MEDLINE | ID: mdl-38087836

ABSTRACT

When (4n +2) π-electrons are located in single planar ring, it conventionally qualifies as aromatic. According Hückel's rule, systems possessing ten π-electrons should be aromatic. Herein we report a series of D5h  Li6 E5 Li6 sandwich structures, representing the first global minima featuring ten π-electrons E5 10- ring (E=Si-Pb). However, these π-electrons localize as five π-lone-pairs rather than delocalized orbitals. The high symmetry structure achieved is a direct consequence of σ-aromaticity, particularly favored in elements from Si to Pb, resulting in a pronounced diatropic ring current flow that contributes to the enhanced stability of these systems.

10.
Chemistry ; 30(1): e202302415, 2024 Jan 02.
Article in English | MEDLINE | ID: mdl-37955853

ABSTRACT

Nowadays, an active research topic is the connection between Clar's rule, aromaticity, and magnetic properties of polycyclic benzenoid hydrocarbons. In the present work, we employ a meticulous magnetically induced current density analysis to define the net current flowing through any cyclic circuit, connecting it to aromaticity based on the ring current concept. Our investigation reveals that the analyzed polycyclic systems display a prominent global ring current, contrasting with subdued semi-local and local ring currents. These patterns align with Clar's aromatic π-sextets only in cases where migrating π-sextet structures are invoked. The results of this study will enrich our comprehension of aromaticity and magnetic behavior in such systems, offering significant insights into coexisting ring current circuits in these systems.

11.
Phys Chem Chem Phys ; 25(40): 27468-27474, 2023 Oct 18.
Article in English | MEDLINE | ID: mdl-37800185

ABSTRACT

Thermodynamic, kinetic, and chemical bonding analysis at the coupled cluster level has been carried out for a series of hypercoordinated carbon compounds with formula CH4Ng2+ (Ng = He-Rn). Results show that these compounds could be stable at room temperature and Born-Oppenheimer molecular dynamics simulations (BOMD) in conjunction with activation energies indicate high kinetic stability. In addition, all chemical bonding descriptors agree with a strong C-Ng covalent bond and a bonding pattern similar to that of CH5+. Finally, BOMD simulations showed that these compounds are fluxional, with a continuous formation/breaking of H-H and C-H bonds. To the best of the authors' knowledge, these results represent the first series of fluxional compounds possessing a covalent bond between a main group element and a noble gas atom.

12.
Pharmaceutics ; 15(8)2023 Aug 02.
Article in English | MEDLINE | ID: mdl-37631286

ABSTRACT

Infusions of Valeriana pilosa are commonly used in Peruvian folk medicine for treating gastrointestinal disorders. This study aimed to investigate the spasmolytic and antispasmodic effects of Valeriana pilosa essential oil (VPEO) on rat ileum. The basal tone of ileal sections decreased in response to accumulative concentrations of VPEO. Moreover, ileal sections precontracted with acetylcholine (ACh), potassium chloride (KCl), or barium chloride (BaCl2) were relaxed in response to VPEO by a mechanism that depended on atropine, hyoscine butylbromide, solifenacin, and verapamil, but not glibenclamide. The results showed that VPEO produced a relaxant effect by inhibiting muscarinic receptors and blocking calcium channels, with no apparent effect on the opening of potassium channels. In addition, molecular docking was employed to evaluate VPEO constituents that could inhibit intestinal contractile activity. The study showed that α-cubebene, ß-patchoulene, ß-bourbonene, ß-caryophyllene, α-guaiene, γ-muurolene, valencene, eremophyllene, and δ-cadinene displayed the highest docking scores on muscarinic acetylcholine receptors and voltage-gated calcium channels, which may antagonize M2 and/or M3 muscarinic acetylcholine receptors and block voltage-gated calcium channels. In summary, VPEO has both spasmolytic and antispasmodic effects. It may block muscarinic receptors and calcium channels, thus providing a scientific basis for its traditional use for gastrointestinal disorders.

13.
RSC Adv ; 13(35): 24499-24504, 2023 Aug 11.
Article in English | MEDLINE | ID: mdl-37588980

ABSTRACT

A new algorithm called Automatic Johnson Cluster Generator (AJCG) is presented, which, as its name indicates, allows the definition of the desired Johnson polyhedron to subsequently carry out all the possible permutations between the atoms that form this polyhedron. This new algorithm allows the exhaustive study of the structures' potential energy surface (PES). In addition, the AJCG algorithm is helpful for the study of three-dimensional compounds such as boranes or Zintl clusters and their structural derivatives with two or more different atoms. The automatic filling of vertices is particularly useful in mixed compounds because of the possibility of taking into account all possible configurations in the structure. As a test system, we investigated the arachno-type E6M24- (E = Si, Ge, Sn; M = Sb, Bi) structure which has eight vertices and complies with Wade-Mingos rules. Initially, we defined a bipyramidal structure (10 vertices), and filled the vertices with the atoms in all possible configurations. Since the selected system has eight atoms, the two remaining vertices were filled with pseudo atoms to complete the structure. After re-optimizing the initial population generated with AJCG, a large number of isomers with energy below 10 kcal mol-1 are identified. These results show that the most stable isomers possess homonuclear M-M bonds, except Sn6Bi24-. Although the overall putative minima differ at the PBE0-D3 and DLPNO-CCSD(T) levels, they are always competitive minima. In addition to using high-precision methodologies to correctly study relative energies, applying solvent effects in highly charged systems becomes mandatory. The aromatic character of these studied systems was demonstrated qualitatively with two- and three-dimensional mapping and quantitatively by calculating the value of the z-component of the induced magnetic field at the cage center, including scalar and spin-orbit correction for relativistic effects. The compounds studied have a high degree of aromaticity, which allows us to establish that despite structural modifications (i.e., from closo to arachno), the aromaticity is preserved.

14.
ACS Omega ; 8(25): 23168-23173, 2023 Jun 27.
Article in English | MEDLINE | ID: mdl-37396283

ABSTRACT

In this article, we studied the capability of bulky groups to contribute to the stabilization of a given compound in addition to the well-known steric effect related to substituents due to their composition (alkyl chains and aromatic groups, among others). For this purpose, the recently synthesized 1-bora-3-boratabenzene anion which contains large substituents was analyzed by means of the independent gradient model (IGM), natural population analysis (NPA) at the TPSS/def2-TZVP level, force field-based energy decomposition analysis (EDA-FF) applying the universal force field (UFF), and molecular dynamics calculations under the GFN2-xTB approach. The results indicate that the bulky groups should not only be considered for their steric effects but also for their ability to stabilize a system that could be very reactive.

15.
Molecules ; 28(11)2023 May 24.
Article in English | MEDLINE | ID: mdl-37298798

ABSTRACT

A series of 2-phenylamino-3-acyl-1,4-naphtoquinones were evaluated regarding their in vitro antiproliferative activities using DU-145, MCF-7 and T24 cancer cells. Such activities were discussed in terms of molecular descriptors such as half-wave potentials, hydrophobicity and molar refractivity. Compounds 4 and 11 displayed the highest antiproliferative activity against the three cancer cells and were therefore further investigated. The in silico prediction of drug likeness, using pkCSM and SwissADME explorer online, shows that compound 11 is a suitable lead molecule to be developed. Moreover, the expressions of key genes were studied in DU-145 cancer cells. They include genes involved in apoptosis (Bcl-2), tumor metabolism regulation (mTOR), redox homeostasis (GSR), cell cycle regulation (CDC25A), cell cycle progression (TP53), epigenetic (HDAC4), cell-cell communication (CCN2) and inflammatory pathways (TNF). Compound 11 displays an interesting profile because among these genes, mTOR was significantly less expressed as compared to control conditions. Molecular docking shows that compound 11 has good affinity with mTOR, unraveling a potential inhibitory effect on this protein. Due to the key role of mTOR on tumor metabolism, we suggest that impaired DU-145 cells proliferation by compound 11 is caused by a reduced mTOR expression (less mTOR protein) and inhibitory activity on mTOR protein.


Subject(s)
Antineoplastic Agents , Naphthoquinones , Neoplasms , Naphthoquinones/pharmacology , Molecular Docking Simulation , Cell Line, Tumor , Cell Proliferation , Apoptosis , TOR Serine-Threonine Kinases/metabolism , Antineoplastic Agents/pharmacology , Drug Screening Assays, Antitumor
16.
J Chem Phys ; 158(16)2023 Apr 28.
Article in English | MEDLINE | ID: mdl-37093138

ABSTRACT

Photophysical, photovoltaic, and charge transport properties of fused core-modified expanded porphyrins containing two pyrroles, one dithienothiophene (DTT) unit, and 1-4 thiophenes (1-4) were inspected by using density functional theory (DFT) and time-dependent DFT. Compounds 1-3 have been investigated experimentally before, but 4 is a theoretical proposal whose photophysical features match those extrapolated from 1 to 3. They exhibit absorption in the range of 700-970 nm for their Q bands and 500-645 nm for their Soret bands. The rise of thiophene rings placed in front of the DTT unit in the expanded porphyrin ring causes a bathochromic shift of the longest absorption wavelength, leading to near-infrared absorptions, which represent 49% of the solar energy. All the systems show a thermodynamically favorable process for the electron injection from the dye to TiO2 and adsorption on a finite TiO2 model. The electron regeneration of the dye is only thermodynamically feasible for the smallest expanded porphyrins 1 and 2 when I-/I3- electrolyte is used. The charge transport study shows that for voltages lower than 0.4 V, junctions featuring pentaphyrin 1 and octaphyrin 4 are more conductive than those containing hexaphyrin 2 or heptaphyrin 3. The results showed that the four fused core-modified expanded porphyrins investigated are potential dyes for applications in dye-sensitized solar cells, mainly pentaphyrin 1 and hexaphyrin 2. Moreover, increasing the number of thiophene rings in the macrocycle proved fruitful in favoring absorption in the near-infrared region, which is highly desired for dye-sensitized solar cells.

17.
ACS Omega ; 8(3): 2880-2886, 2023 Jan 24.
Article in English | MEDLINE | ID: mdl-36713707

ABSTRACT

The electronic transmutation (ET) concept states that when an element with atomic number Z gains an electron, it transmutes into a Z + 1 element, leading to species that possess similar chemical bonding patterns and geometric structures regarding the original (Z + 1) element. In this work, the opposite concept, that is, the inverse ET, is assessed. For this purpose, several main group compounds have been analyzed in terms of the adaptive natural density partitioning. The obtained results suggest that when an atom Z loses an electron, it transmutes into a Z - 1 atom, acquiring its geometrical structure and bonding pattern.

18.
Chemphyschem ; 24(4): e202200601, 2023 Feb 14.
Article in English | MEDLINE | ID: mdl-36264712

ABSTRACT

In this work, we explore, using high-level calculations, the ability of BH4 + to interact with noble gases. The He system is energetically unstable, while the Ne system could only be observed at cryogenic temperatures. In the case of the Ar, Kr and Xe systems, all are energetically stable, even at room temperature. The different chemical bond descriptors reveal a covalent character between B and the noble gas from Ar to Rn. However, this interaction gradually weakens the multicentric bond between the boron atom and the H2 fragment. Thus, although BH4 Rn+ exhibits a strong covalent bond, it tends to dissociate at room temperature into BH2 Rn+ +H2 .

19.
ACS Omega ; 7(25): 21939-21945, 2022 Jun 28.
Article in English | MEDLINE | ID: mdl-35785290

ABSTRACT

Aromaticity is a useful tool to rationalize the structure, stability, and reactivity in several compounds. Although aromaticity is not directly an observable, it is well accepted that electronic delocalization around the molecular ring is a key stabilizing feature of aromatic compounds. This contribution presents a systematic evaluation of the capability of delocalization and reactivity criteria to describe aromaticity in a set of fluorinated benzenes. The aromaticity indices are compared with quantities obtained from the magnetic criteria of aromaticity, i.e., the strength of the ring current induced by an external magnetic field and the popular NICS zz (1) index. In this evaluation, the indices based on delocalization criteria used are aromatic fluctuation index (FLU), para-delocalization index (PDI), PDIπ, and the multicenter delocalization index (MCI). In addition, indices based on the bifurcation values of scalar functions are derived from electron density such as electron localization function (the π contribution, ELFπ) and the π contribution of the localized orbital locator (LOLπ). Furthermore, reactivity indices based on chemical reactivity and the information-theoretic (reactivity) approach are para-linear response (PLR), Shannon entropy, Fisher information, and Ghosh-Berkowitz-Parr (GBP) entropy. The results obtained show that the delocalization-based indicators present a high sensitivity to slight changes in aromaticity and that the reactivity criterion can be considered as a complementary tool for the study of this phenomenon, even when these changes are minimal. These results encourage the use of multiple indicators for a complete understanding of aromaticity in various chemical compounds.

20.
Antioxidants (Basel) ; 11(7)2022 Jul 07.
Article in English | MEDLINE | ID: mdl-35883828

ABSTRACT

Valeriana pilosa is usually employed in Peruvian folk medicine in the form of infusion to treat stomach pain, and has antispasmodic, relaxing, sleep-promoting, and sedative properties, as well as is an anti-inflammatory. In this study, Valeriana pilosa essential oil (VPEO) was obtained by hydrodistillation, analyzed by GC and GC/MS, and 47 compounds were identified. Major oil components were α-patchoulene (5.8%), α-humulene (6.1%), seychellene (7.6%), and patchoulol (20.8%). Furthermore, we assessed the in vitro antioxidant activities, molecular docking, and Ligand Efficiency studies on enzymes involved in cellular redox pathways such as CYP2C9, catalase, superoxide dismutase, and xanthine oxidase. Essential oil antioxidant activities were assessed by FRAP, ABTS•+, and DPPH• radical scavenging activity. VPEO displays high antioxidant activity as compared to essential oils of Valeriana jatamansi and Valeriana officinalis oil roots. In addition, molecular docking and ADMET prediction was employed to compare the absorption, metabolism, and toxicity properties of Valeriana pilosa compounds. In the molecular docking studies, limonene, p-cimene, carvone, α-cubebene, cyclosativene, α-guaiene, allo-aromadendrene, valencene, and eremophyllene were the compounds with the best docking score on CYP2C9 and xanthine oxidase. Thus, volatile components of Valeriana pilosa could be associated with the detected antioxidant activity, acting as putative inhibitors of CYP2C9 and xanthine oxidase.

SELECTION OF CITATIONS
SEARCH DETAIL
...