Association between biomarkers of zinc and copper status and heart failure: a meta-analysis.

AIMS: Previous studies have investigated the relationship between heart failure (HF) and levels of zinc and copper, but conflicting results have been reported. This meta-analysis aims to clarify the role of zinc and copper in HF progression by examining the associations between HF and concentrations of these minerals. METHODS AND RESULTS: We utilized STATA 12.0 software to calculate the standard mean difference (SMD) and 95% confidence interval (CI) for serum zinc and copper levels in patients with HF compared with healthy controls (HCs). The meta-analysis indicated a lower serum zinc level in patients with HF compared with HCs, using a random effects model (SMD = -0.77; 95% CI: -1.01, -0.54; I2 = 61.9%, the P-value for Q test = 0.002). Additionally, the meta-analysis showed an increased serum copper level in patients with HF compared with HCs, using a random effects model (SMD = 0.66; 95% CI: 0.09, 1.23; I2 = 93.8%, the P-value for Q test < 0.001). Meta-regression analysis indicated that publication year, age, and gender were not responsible for heterogeneity across studies. CONCLUSIONS: This meta-analysis demonstrates that patients with HF have lower serum zinc and higher copper concentrations compared with healthy subjects. However, the potential of zinc supplementation as a therapy for HF should be approached with caution. The heterogeneity among the included studies was found to be high. It is recommended that further well-designed large sample studies be conducted to validate these findings.

Effect of Phenol and Alkylamide Interaction on α-Glucosidase Inhibition and Cellular Antioxidant Activity during In Vitro Digestion: Using Szechuan Pepper (Zanthoxylum genus) as a Model.

Although recent evidence indicated significant phenol and alkylamide interaction in aqueous solutions, the gastrointestinal digestion influence of the combination remains unclear. This study aims to investigate phenol and alkylamide interaction during in vitro digestion, focusing on bioaccessibility and bioactivity, including α-glucosidase inhibition and cellular antioxidant activity. Additionally, the structural mechanism of phenol and alkylamide interaction during in vitro digestion was explored. The results indicated that the presence of phenols and alkylamides significantly increased or decreased their respective bioaccessibility, depending on the Zanthoxylum varieties. Furthermore, although antagonistic phenol/alkylamide interaction was evident during α-glucosidase inhibition, cellular oxidative stress alleviation, and antioxidant gene transcription upregulation, this effect weakened gradually as digestion progressed. Glycoside bond cleavage and the methylation of phenols as well as alkylamide isomerization and addition were observed during digestion, modifying the hydrogen bonding sites and interaction behavior. This study provided insights into the phenol/alkylamide interaction in the gastrointestinal tract.

Fabrication, in-vitro digestion and pH-responsive release behavior of soy protein isolate glycation conjugates-based hydrogels.

Hydrogel made by glycated soy protein isolate (SPI) conjugates is a promising gastrointestinal targeted delivery system for bioactives. In this study, SPI conjugates were prepared with dextran molecules at various molecular weights by Maillard reaction -based heating, and then used to fabricate hydrogel aided by transglutaminase. The modification on the structure, interfacial and rheological properties of SPI by dextran was studied. The physicochemical properties, digestion behavior and curcumin-encapsulation capacity of resultant SPI-dextran hydrogels were comprehensively studied. As compared to SPI and SPI-glucose conjugates-based hydrogels, SPI-dextran hydrogels showed lower mechanical properties but more homogeneous gel network. Dextran with higher molecular weight showed lower grafting degree on SPI, but was more effective on improving the thermos-set gel performance, and resistance to in vitro gastrointestinal digestion. The contribution of glycinin and ß-conglycinin, two major individual proteins of SPI, in the dextran conjugates formation were predicated by molecular docking for the first time. The impact of molecular weight of dextran on glycated SPI hydrogel-based delivery systems was comprehensively investigated, which is promising for development of functional food applications.

Effects of glycation methods on the interfacial behavior and emulsifying performance of soy protein isolate-gum Arabic conjugates.

Glycated conjugation of plant protein such as soy protein isolate (SPI) with saccharides is one popular strategy to modify the physicochemical characteristics of these plant protein resources, which may be affected by the glycation methods including dry-heating and wet-heating. In this study, the impact of these two glycation methods on the rheological and emulsifying properties of a binary system made by SPI-gum Arabic (GA) was studied. The results indicated that dry-heating conjugates had higher viscosity and more elastic characteristics than those wet-heating conjugates. The emulsifying properties of SPI-GA conjugates by different preparation routes were evaluated by various oil phases including eugenol, cinnamaldehyde and soybean oil. Overall, emulsions stabilized by dry-heating conjugates showed lower zeta-potential value than those with wet heating conjugates. The interfacial properties of these conjugates were compared using soybean oil emulsion as a model. Higher emulsifying ability and stability were obtained by emulsions with dry-heating conjugates, which was attributed to their more compact structures, higher protein adsorption capacity and thicker viscoelastic films formed at the interface, and therefore enhanced electrostatic repulsion between droplets. The findings in this study are useful for fabrication and utilization of protein-polysaccharide glycation conjugates as emulsifiers in functional foods.

Effection of Lactic Acid Dissociation on Swelling-Based Short-Chain Fatty Acid Vesicles Nano-Delivery.

Functionalized small-molecule assemblies can exhibit nano-delivery properties that significantly improve the bioavailability of bioactive molecules. This study explored the self-assembly of short-chain fatty acids (FA, Cn < 8) to form novel biomimetic nanovesicles as delivery systems. Lactic acid is involved in the regulation of multiple signaling pathways in cancer metabolism, and the dissociation of lactic acid (LA) is used to regulate the delivery effect of short-chain fatty acid vesicles. The study showed that the dissociation of lactic acid caused pH changes in the solution environment inducing hydrogen ion permeability leading to rapid osmotic expansion and shape transformation of FA vesicles. The intrinsic features of FA vesicle formation in the LA environment accompanied by hydrogen ion fluctuations, and the appearance of nearly spherical vesicles were investigated by transmission electron microscopy (TEM) and Fourier Transform Infrared Spectroscopy (FTIR). Compared with the vesicle membrane built by surfactants, the FA/LA composite system showed higher permeability and led to better membrane stability and rigidity. Finally, membrane potential studies with the IEC cell model demonstrate that lactate dissociation capacity can effectively increase the cellular adsorption of FA vesicles. Altogether, these results prove that FA vesicles can function as a stand-alone delivery system and also serve as potential development strategies for applications in a lactate environment.

Quantitative structure-pungency landscape of sanshool dietary components from Zanthoxylum species.

The molecular basis of the pungency of sanshool dietary components from the Zanthoxylum species has been firstly addressed by constructing the statistically significant and highly predictive quantitative structure-pungency relationship models along with the pharmacophore models. The important pungent structural characters in the isobutylamide moiety and linear carbon chains were elucidated in this study that maintained the suitable spatial packing and electrostatic interactions with their receptors. Our results also revealed that the amide moiety, N-isobutyl moiety with suitable bulky and restricted electronegative substituents, and the relatively long straight carbon chains with suitable (conjugated) CC bonds or heteroatoms at regular intervals were essential for the high pungency. The pungency of 42 new sanshools was predicted, compared with the rough experimental data, and ultimately classified into weak, medium and strong types. Most of these sanshools were found to have good oral bioavailability and acceptable pharmacokinetic properties.

Mechanistic elucidation of the oral pungency of capsaicin-related dietary components: Spatial structural insights.

The mechanistic insights into the oral pungency of capsaicin-related dietary components have been elucidated from the spatial structural perspectives by establishing statistically significant and highly predictive three-dimensional quantitative structure-property relationship models. Our results visualized the possible favorable and unfavorable steric and electrostatic interactions with the pungent receptors with the assistance of pharmacophore models, and revealed the suitable electronegative/positive or bulky substitutions in the vanillyl group, amide moiety, linear alkyl chain and their adjacent structural area of capsaicin required for the desired pungency, which was not only complementary to the viewpoints proposed in our previous structure-pungency correlations, but also was applied to clearly clarify the pungent differences in compounds, and well predict the pungency of 21 capsaicin analogs though with ambiguous experimental data on pungency. Hopefully, this work would benefit the overall understanding of the pungent mechanism and facile discovery/design of analogs with desired pungency to expand their applications in foods.

Inhibition of starch digestion: The role of hydrophobic domain of both α-amylase and substrates.

The physicochemical mechanism of starch digestion is very complicated since it may be affected by the non-valence interactions of the amylase inhibitor with the substrate or the enzyme. The role of hydrophobic interaction in the process of starch digestion is not clear. In this study, pluronics (PLs) with different hydrophobicity were used as model amphiphilic compounds to study their inhibition on starch digestion using multi-spectroscopic methods. The results showed that the hydrophobic nature of PLs changed starch structure, but it had a greater effect on the structure of α-amylase by exposing more tryptophan residues and increasing α-helix and ß-sheet contents. Further investigation by using different chain-length fatty acids confirmed the results. The finding in this study is informative to design and fabricate α-amylase inhibitors for controlling starch digestion at the molecular level.

Molecular basis and potential applications of capsaicinoids and capsinoids against the elongation of etiolated wheat (Triticum aestivum L.) coleoptiles in foods.

Capsaicinoids and capsinoids from dietary peppers have promising sensory properties and bioactivity, but the molecular basis of their penetration mechanism through cell lipid bilayers and its relationship to their bioavailability as food constituents are still poorly understood. Herein, statistically significant linear and quadratic quantitative structure-activity relationships were constructed to derive the essential structural elements required for their bioactivity against the elongation of etiolated wheat coleoptiles that mainly occurs via penetration. The resultant optimal models had high predictivity and reliability (r2 > 0.825 and r2pred > 0.950), which elucidate the importance of steric structural elements. Besides, their mechanistic hypothesis and rational design strategy were proposed, and the correlation between this bioactivity and their food-sensory properties was supposed. Finally, the bioactivity of newly designed analogs with methyl terminals and/or conjugated CC links was screened. Hopefully, this work would benefit the better understanding of their penetration mechanism and facile identification of bioactive analogs for designing food/drug formulations.

Synergistic interaction between exogenous and endogenous emulsifiers and its impact on in vitro digestion of lipid in crowded medium.

Control of lipid digestibility by various food components has received great attention in recent decades. However, there is limited literature on investigating the synergistic effect of exogenous emulsifiers and endogenous sodium cholate (SC) on lipid digestion in a simulated physiological crowded medium. In this work, the synergistic interaction of Tween80 and SC according to the regular solution theory, and the hydrolysis of lipid emulsions containing tricaprylin, glyceryltrioleate or soybean oil in crowding medium was studied. The results show that emulsions stabilized by a combination of Tween80 and SC showed higher digestion rate and transformation than those with Tween80 or SC. The digestion rate could be increased by polyethylene glycols (PEGn) with varying crowding degree. The denaturation temperature of the lipase was increased in macromolecular crowded medium. This work allows for better understanding of the interaction between the amphiphiles and the macromolecular crowding effect on lipase digestion in the physiological environment.

Quantitative structure-retention relationships of the chromatographic retentions of phthalic acid ester contaminants in foods.

The harmful health effects caused by phthalic acid esters have been supported from the increasing scientific evidence, developing the efficient methodologies to monitor the levels of phthalic acid esters in various foods become especially important from the aspects of human exposure assessment and their migration mechanistic understanding. In this study, quantitative structure-retention relationship studies on both the gas and liquid chromatographic retention times of 23 phthalic acid esters were performed by genetic function approximation, and the optimal quantitative structure-retention relationship models (r2  > 0.980, r2 CV  > 0.960, and r2 pred  > 0.865) passed the statistical tests of cross-validation, randomization, external prediction, Roy' rm 2 metrics, Golbraikh-Tropsha' criteria and applicability domain. The established predictive models elucidate the structural requirements for the retention of phthalic acid esters over different chromatographic columns, which were finally used to predict the retention times of 11 new phthalic acid esters. Hopefully, this work could provide useful guidelines for better understanding and accurate prediction of the retention behavior of undetermined phthalic acid esters when lacking standard samples or under poor experimental conditions, and make the simultaneous identification and quantification of numerous phthalic acid esters possible.

A [2]pseudorotaxane based on a pillar[6]arene and its application in the construction of a metallosupramolecular polymer.

A novel metallosupramolecular polypseudorotaxane constructed by metal coordination and pillar[6]arene-based molecular recognition was built. First, a [2]pseudorotaxane based on a mono(ethylene oxide) substituted pillar[6]arene P6 and a paraquat derivative guest G was prepared. Then Ag+ was used to fabricate the metallosupramolecular polypseudorotaxane based on a metal coordination polymer backbone.

Vesicle formation by ultrashort alkyl-phosphonic acids and serine in aqueous solutions.

Vesicles possess unique biofilm structures and offer biomimetic advantages for drug and gene delivery. Herein, we report the spontaneous vesicle formation from ultrashort alkyl-phosphonic acids in the presence of amino acids. The aggregation characteristics and self-assembly structures of vesicles in aqueous solution were investigated by using dynamic light scattering, zeta potential, and cryo-transmission electron microscopy. We combined low-field nuclear magnetic resonance and Fourier transform infrared spectroscopy to study the H-proton-induced multilamellar vesicle formation. When we increased the molar fraction of serine, stable and closed spherical vesicles were formed at relatively low critical micelle concentrations. This transition of the self-assembled structure indicates that vesicle formation occurs when the chain length and the magnitude of the surface charge cause a fluctuation in the volume of the vesicle. Density functional theory reveals the critical role of the mixed alkyl-phosphonic acid/amino acid-enhanced electrostatic attraction between the head groups and hydrogen bonds associated with the aggregated states.

Multiple quantitative structure-pungency correlations of capsaicinoids.

The comprehensive mechanistic understanding of pungency and the binding interactions between pungent capsaicinoids from foods and their receptors have attracted increasing attention in food sensory and pharmaceutical fields. In this study, linear and quadratic statistically significant quantitative structure-pungency correlations have firstly been established for capsaicinoids by combining genetic function approximation and brute force approach and subsequently validated by the tests of cross validation, randomization, external prediction, Roy's rm2 metrics and Golbraikh-Tropsha's criteria. The resultant optimal predictive correlation models have strong internal and external predictive capacities (r2 = 0.949-0.989, r2CV = 0.860-0.955, r2pred = 0.859-0.904), which elucidate the elementary electrostatic, hydrogen bonding, hydrophobic and steric structural requirements for the pungent perception of capsaicinoids. Finally, a series of new capsaicinoids was designed based on the insights from the established correlation models, and most of which showed excellent predicted pungency potency and acceptable ADMET properties.

Vesicles from the self-assembly of the ultra-small fatty acids with amino acids under aqueous conditions.

The properties of vesicles formed from the self-assembly of amphiphilic molecules can mimic the functionality of the natural lipid membranes. In this study, the self-assembly process of the amphiphilic structures formed by the interaction between ultra-small fatty acids [FAs, Cn (n = 4-8)] and amino acids (AAs) to generate vesicles under aqueous conditions were investigated in detail, along with the corresponding dynamic vesiculation mechanisms. Our results showed that the molar ratio of FAs/AAs and the chain length of FAs largely affected the structural characteristics and dispersion of vesicles. The detailed information about the entire size distributions and morphology of obtained vesicles were explored by the cryogenic transmission electron microscopy (Cryo-EM). Fourier transform infrared (FT-IR) spectra and quantum calculations suggested that the intermolecular hydrogen bond and electrostatic interactions between ultra-small molecules (FAs and AAs) during the aggregation processes were responsible for the formation of vesicles, where the hydrogen-bonding effect was dominant. Our findings shed new light on the effective and simple preparation of biological vesicles via ultra-small molecules self-assembly in aqueous solutions, which may have potential applications in vesicle physiology and drug delivery systems, and also get a mature understanding of the fundamental intermolecular interactions in life process.

Landscape of the structure-O-H bond dissociation energy relationship of oximes and hydroxylamines.

The relationship between the homolytic O-H bond dissociation enthalpies (BDEs) and the structures of N-oxyl radical precursors (i.e. hydroxylamines and oximes) is important to predict their reactivity. Yet several crucial facts remain hidden to complete the picture such as the substituent electronic effects on the BDEs of oximes. In this work, the O-H BDEs of 120 hydroxylamines and 120 oximes have been calculated. It was found that the majority of the iminoxyl radicals are σ radicals, except for some π radicals. The resonance effect dominates the electronic effects on the BDEs of oximes, and electron-donating conjugation increases the BDE. However, both the resonance and the inductive effects are important in the BDEs of hydroxylamines; meanwhile, the BDEs increase with the increase of the electron-withdrawing ability of the substituents. Besides, the ΔBDEs of oximes and hydroxylamines with two substituents almost equal the algebraic sum of the ΔBDEs of single substituents. In addition, dipole-dipole repulsion is responsible for the difference in the BDEs of open chain and cyclic acyl hydroxylamines. Although the ring strain affects the N-O bonding property of nitroxide radicals, it has negligible effect on the BDEs of oximes. These new rules provide a complete and precise understanding of the structure-bond energy relationship of N-oxyl radical precursors.

Cyclo[4]carbazole, an Iodide Anion Macrocyclic Receptor.

A novel preorganized and rigid iodide anion macrocyclic receptor, cyclo[4]carbazole (Cy[4]C), is reported here. The structure of Cy[4]C was confirmed by single-crystal X-ray analysis. The binding affinity of Cy[4]C for iodide anion was investigated by UV-vis and 1H NMR spectroscopic techniques. The crystal structure of the complex between Cy[4]C and chloroform also provided evidence for the recognition ability of Cy[4]C toward iodide anion. Furthermore, the 1:1 complexation stoichiometry between Cy[4]C and iodide anion was confirmed by high-resolution mass spectrometry and molecular modeling.

Structures and Electronic Properties of Lithium Chelate-Based Ionic Liquids.

The conformations, electronic properties, and interaction energies of four chelate-based ionic liquids [Li(EA)][Tf2N], [Li(HDA)][Tf2N], [Li(DEA)][Tf2N], and [Li(DOBA)][Tf2N] have been theoretically explored. The reliability of the located conformers has been confirmed via the comparison between the simulated and experimental infrared spectra. Our results show that the N-Li and O-Li coordinate bonds in cation are elongated as the numbers of coordinate heteroatoms of alkanolamine ligands to Li(+) increased. Also the binding energies between Li(+) and ligands are increased and the interaction energies between cations and Tf2N anion are decreased. The cation-anion interaction energies follow the order of [Li(DOBA)][Tf2N] < [Li(HDA)][Tf2N] < [Li(DEA)][Tf2N] < [Li(EA)][Tf2N], which fall within the energetic ranges of conventional ionic liquids. Interestingly, the strongest stabilization orbital interactions in these ionic liquids and their cations revealed by the natural bond orbital analysis lie in the interaction between the lone pair (LP) of the coordinate heteroatoms in ligands or anion as donors and the vacant valence shell nonbonding orbital (LP*) of Li(+) as acceptors, which are very different from that of conventional ionic liquids. Moreover, the charges transferred from cations to anion are quite similar, and the charge of Li(+) is proposed for possibly predicting the order of the interaction energies of ionic liquids in series. The present study allows for the deeper understanding the differences between chelate-based ionic liquids and conventional ionic liquids.

Theoretical studies on CO2 capture behavior of quaternary ammonium-based polymeric ionic liquids.

Quaternary ammonium-based polymeric ionic liquids (PILs) are novel CO2 sorbents as they have high capacity, high stability and high binding energy. Moreover, the binding energy of ionic pairs to CO2 is tunable by changing the hydration state so that the sorbent can be regenerated through humidity adjustment. In this study, theoretical calculations were conducted to reveal the mechanism of the humidity swing CO2 adsorption, based on model compounds of quaternary ammonium cation and carbonate anions. The electrostatic potential map demonstrates the anion, rather than the cation, is chemically preferential for CO2 adsorption. Further, the proton transfer process from water to carbonate at the sorbent interface is successfully depicted with an intermediate which has a higher energy state. By determining the CO2 adsorption energy and activation energy at different hydration states, it is discovered that water could promote CO2 adsorption by reducing the energy barrier of proton transfer. The adsorption/desorption equilibrium would shift to desorption by adding water, which constitutes the theoretical basis for humidity swing. By analyzing the hydrogen bonding and structure of the water molecules, it is interesting to find that the CO2 adsorption weakens the hydrophilicity of the sorbent and results in release of water. The requirement of latent heat for the phase change of water could significantly reduce the heat of adsorption. The special "self-cooling" effect during gas adsorption can lower the temperature of the sorbent and benefit the adsorption isotherms.

Elucidating Interactions between DMSO and Chelate-Based Ionic Liquids.

The C-D bond stretching vibrations of deuterated dimethyl sulfoxide ([D6 ]DMSO) and the C2 -H bond stretching vibrations of 1,1,1,5,5,5-hexafluoropentane-2,4-dione (hfac) ligand in anion are chosen as probes to elucidate the solvent-solute interaction between chelate-based ionic liquids (ILs) and DMSO by vibrational spectroscopic studies. The indirect effect from the interaction of the adjacent S=O functional group of DMSO with the cation [C10 mim](+) and anion [Mn(hfac)3 ](-) of the ILs leads to the blue-shift of the C-D stretching vibrations of DMSO. The C2 -H bond stretching vibrations in hfac ligand is closely related to the ionic hydrogen bond strength between the cation and anion of chelate-based ILs. EPR studies reveal that the crystal field of the central metal is kept when the chelate-based ILs are in different microstructure environment in the solution.