Molecular Structural Features Research Articles

Enhanced Four‐Electron Oxygen Reduction Selectivity of Clamp‐Shaped Cobalt(II) Porphyrin(2.1.2.1) Complexes

AbstractThe molecular structure, electrochemistry, spectroelectrochemistry and electrocatalytic oxygen reduction reaction (ORR) features of two CoII porphyrin(2.1.2.1) complexes bearing Ph or F5Ph groups at the two meso‐positions of the macrocycle are examined. Single crystal X‐ray analysis reveal a highly bent, nonplanar macrocyclic conformation of the complex resulting in clamp‐shaped molecular structures. Cyclic voltammetry paired with UV/Vis spectroelectrochemistry in PhCN/0.1 M TBAP suggest that the first electron addition corresponds to a macrocyclic‐centered reduction while spectral changes observed during the first oxidation are consistent with a metal‐centered CoII/CoIII process. The activity of the clamp‐shaped complexes towards heterogeneous ORR in 0.1 M KOH show selectivity towards the 4e− ORR pathway giving H2O. DFT first‐principle calculations on the porphyrin catalyst indicates a lower overpotential for 4e− ORR as compared to the 2e− pathway, consistent with experimental data.

Determination of the molecular structure and spectroscopic properties of capsaicin

In this study, the ground state molecular structure and spectroscopic features of cis- and trans-forms of capsaicin were investigated using DFT (B3LYP) invoking 6–311++G(d,p) basis set. The optimized geometry of capsaicin was determined for the isolated molecule in a vacuum, and then the vibrational spectra –IR and Raman-were obtained, and the assignments of fundamental vibrational modes were done. By applying the GIAO method, proton and carbon chemical shifts were computed for the gas and solvated phases. Besides using the TD-DFT, the Hirshfeld surface and Molecular Electrostatic Potential surfaces were obtained and evaluated to understand the electronic properties. The Total and partial density of state (TDOS and PDOS) spectra were also examined. All obtained computational results were compared with the previously reported experimental data. A high accuracy was obtained for the ground state geometrical structure, and thus, the vibrational frequencies especially lie on the finger print region are predicted also with a high correlation. Similarly, the optimization of chemical shift values calculated by considering solvent effects with experimental data were found as high R2 values of 0.9953 and 0.9455 for C and H atoms, respectively. This comparison shows that the DFT method precisely predicts capsaicin's molecular and spectroscopic characteristics.

Revealing the Correlation between Molecular Structure and Corrosion Inhibition Characteristics of N-Heterocycles in Terms of Substituent Groups

Controlling metal corrosion can directly address the waste of metal and the environmental pollution and resource depletion caused by metal recycling, very significant factors for green and sustainable development. The addition of corrosion inhibitors is a relatively cost-effective means of corrosion prevention. Among these, N-heterocycles have been widely used because heteroatoms contain lone pairs of electrons that can be strongly adsorbed onto metals, protecting them in highly corrosive environments at relatively low concentrations. However, due to the large variety of N-heterocycles, their corrosion inhibition characteristics have seldom been compared; therefore, the selection of appropriate N-heterocycles in the development of anti-corrosion products for specific applications was very difficult. This review systematically analyzed the influence of different substituents on the corrosion inhibition performance of N-heterocycles, including different alkyl chain substituents, electron-donating and electron-withdrawing substituents, and halogen atoms, respectively. The correlation between the molecular structure and corrosion inhibition characteristics of N-heterocycles was comprehensively revealed, and their action mechanism was analyzed deeply. In addition, the toxicity and biodegradability of N-heterocycles was briefly discussed. This study has provided a significant guideline for the development of green, promising corrosion inhibitors for advanced manufacturing and clean energy equipment protection.

Bioaccumulation of Per- and Polyfluoroalkyl Substances (PFAS) in Ferns: Effect of PFAS Molecular Structure and Plant Root Characteristics.

The present study assessed the bioaccumulation potential of per- and polyfluoroalkyl substances (PFAS) in ferns and linked root uptake behaviors to root characteristics and PFAS molecular structure. Tissue and subcellular-level behavioral differences between alternative and legacy PFAS were compared via an electron probe microanalyzer with energy dispersive spectroscopy (EPMA-EDS) and differential centrifugation. Our results show that ferns can accumulate PFAS from water, immobilize them in roots, and store them in harvestable tissue. The PFAS loading in roots was dominated by PFOS; however, a substantial amount of associated PFOS could be rinsed off by methanol. Correlation analyses indicated that root length, surface and project area, surface area per unit length of the root system, and molecular size and hydrophobicity of PFAS were the most significant factors affecting the magnitude of root uptake and upward translocation. EPMA-EDS images together with exposure experiments suggested that long-chain hydrophobic compounds tend to be adsorbed and retained on the root epidermis, while short-chain compounds are absorbed and quickly translocated upward. Our findings demonstrated the feasibility of using ferns in phytostabilization and phytoextraction initiatives of PFAS in the future.

Construction of macromolecular model and analysis of oxygen absorption characteristics of Hongyang No. 2 coal mine

Understanding the molecular structure characteristics of coal from the molecular level is of great significance for realizing rational utilization and efficient transformation of coal. The molecular structure of coal samples from 1304 working face in No.13 coal seam of Hongyang No.2 Mine (HY) was studied by industrial analysis, elemental analysis, Nuclear magnetic resonance carbon spectroscopy (13C NMR) and Fourier transform infrared spectroscopy (FTIR). The results show that the aromatic compounds in coal samples of HY are mainly naphthalene ring structures. The aliphatic structure mainly consists of methyl, ethyl side chains and cycloalkanes. The ratio of aromatic bridge carbon to weekly carbon in molecular structure is 0.17. Oxygen atoms exist in the form of carbonyl, hydroxyl, and ether bonds, nitrogen atoms exist in the form of pyridine and pyrrole respectively, and sulfur atoms exist in the form of thiophene. Based on this, the planar structure model of coal macromolecule in HY is constructed, and its molecular formula is C129H88O29N2S, and its molecular weight is 2160. The structure optimization and annealing kinetics simulation of a single macromolecule model were carried out, and a stable three-dimensional coal model of HY was obtained. In addition, the oxygen absorption characteristics of coal samples in HY were studied by molecular dynamics and quantum chemistry. The results show that the adsorption capacity of the Wiser model is less than that of HY coal model. This is because, compared with the Wiser model, the content of oxygenated aliphatic hydrocarbons in the molecular structure of HY coal is higher, and the condensation degree of polycyclic aromatic hydrocarbons is lower. Due to the stronger physical adsorption capacity of hydroxyl, ether bond, and carbonyl on O2, HY Mine has stronger physical adsorption capacity on O2.

Structural variety of Cu (II), Ni (II), and Co (II) complexes of a hydrazone based on 5‐acetyl‐4‐hydroxy‐2H‐1,3‐thiazine‐2,6(3H)‐dione: Synthesis, spectroscopic, density functional theory, antitumor, and docking studies

New nickel (II), cobalt (II), and several copper (II) complexes have been synthesized from the hydrazone ligand (AHTDSH; H2L); which obtained from 5‐acetyl‐4‐hydroxy‐2H‐1,3‐thiazine‐2,6(3H)‐dione with salicylaldehyde hydrazone. The structures of H2L ligand and the prepared complexes were confirmed by spectroscopic and analytical techniques. The ligand behaves as bis (monobasic bidentate) and dibasic tetradentate chelating agent via azomethine nitrogen and phenolic oxygen atoms. Octahedral geometries have been assigned for the prepared complexes. The Coats–Redfern equations were used to estimate the kinetic parameters (Ea, A, H, S, and G) of the thermal decomposition stages. The molecular structural characteristics of the ligand and its metal complexes were estimated based on density functional theory (DFT) level implemented in the Gaussian 09 software at B3LYP/6‐311G(d,p) level and the theoretical data were connected with the results of the experimental work. The anticancer activity of AHTDSH ligand and its complexes was demonstrated toward HepG2 cell lines. The interaction between the chemical and the active site of the CDK2 kinase was examined using a docking study of the hydrazone ligand and its complexes.

Rapid authentication of different herbal medicines by heating online extraction electrospray ionization mass spectrometry

The rapid and accurate authentication of traditional Chinese medicines (TCMs) has always been a key scientific and technical problem in the field of pharmaceutical analysis. Herein, a novel heating online extraction electrospray ionization mass spectrometry (H-oEESI-MS) was developed for the rapid and direct analysis of extremely complex substances without the requirement for any sample pretreatment or pre-separation steps. The overall molecular profile and fragment structure features of various herbal medicines could be completely captured within 10–15 s, with minimal sample (<0.5 mg) and solvent consumption (<20 μL for one sample). Furthermore, a rapid differentiation and authentication strategy for TCMs based on H-oEESI-MS was proposed, including metabolic profile characterization, characteristic marker screening and identification, and multivariate statistical analysis model validation. In an analysis of 52 batches of seven types of Aconitum medicinal materials, 20 and 21 key compounds were screened out as the characteristic markers of raw and processed Aconitum herbal medicines, respectively, and the possible structures of all the characteristic markers were comprehensively identified based on Compound Discoverer databases. Finally, multivariate statistical analysis showed that all the different types of herbal medicines were well differentiated and identified (R2X > 0.87, R2Y > 0.91, and Q2 > 0.72), which further verified the feasibility and reliability of this comprehensive strategy for the rapid authentication of different TCMs based on H-oEESI-MS. In summary, this rapid authentication strategy realized the ultra-high-throughput, low-cost, and standardized detection of various complex TCMs for the first time, thereby demonstrating wide applicability and value for the development of quality standards for TCMs.

A Simple Nonfused Ring Electron Acceptor with a Power Conversion Efficiency Over 16%†

Comprehensive SummaryBy simplifying the π‐bridge unit, a nonfused ring electron acceptor (NFREA) BM‐2F was designed and synthesized with several high‐yield steps. The specific molecular structure features of BM‐2F are planar molecular backbone and out‐of‐plane side chain, which is favorable for charge transport and can suppress the over‐aggregation. BM‐2F based neat and blend films display obvious face‐on molecular orientation. Specially, D18:BM‐2F based blend film can form good bicontinuous interpenetrating network. More excitingly, a power conversion efficiency of 16.15% was achieved with D18:BM‐2F based photovoltaic devices, which is the highest one based on NFREAs. Our researches manifest that NFREA is a promising direction for low‐cost and high‐performance organic solar cells.

Sustainable Synthesis, Antiproliferative and Acetylcholinesterase Inhibition of 1,4- and 1,2-Naphthoquinone Derivatives.

This work describes the design, sustainable synthesis, evaluation of electrochemical and biological properties against HepG2 cell lines, and AChE enzymes of different substituted derivatives of 1,4- and 1,2-naphthoquinones (NQ). A microwave-assisted protocol was optimized with success for the synthesis of the 2-substituted-1,4-NQ series and extended to the 4-substituted-1,2-NQ family, providing an alternative and more sustainable approach to the synthesis of naphthoquinones. The electrochemical properties were studied by cyclic voltammetry, and the redox potentials related to the molecular structural characteristics and the biological properties. Compounds were tested for their potential anti-cancer activity against a hepatocellular carcinoma cell line, HepG2, using MTT assay, and 1,2-NQ derivatives were found to be more active than their 1,4-NQ homologues (3a-f), with the highest cytotoxic potential found for compound 4a (EC50 = 3 μM). The same trend was found for the inhibitory action against acetylcholinesterase, with 1,2-NQ derivatives showing higher inhibition50µM than their 1,4-NQ homologues, with 4h being the most potent compound (Inhibition50µM = 85%). Docking studies were performed for the 1,2-NQ derivatives with the highest inhibitions, showing dual binding interactions with both CAS and PAS sites, while the less active 1,4-NQ derivatives showed interactions with PAS and the mid-gorge region.

Molecular evolution and population genetics of glutamate decarboxylase acid resistance pathway in lactic acid bacteria.

Glutamate decarboxylase (GAD) pathway (GDP) is a major acid resistance mechanism enabling microorganisms' survival in low pH environments. We aimed to study the molecular evolution and population genetics of GDP in Lactic Acid Bacteria (LAB) to understand evolutionary processes shaping adaptation to acidic environments comparing species where the GDP genes are organized in an operon structure (Levilactobacillus brevis) versus lack of an operon structure (Lactiplantibacillus plantarum). Within species molecular population genetic analyses of GDP genes in L. brevis and L. plantarum sampled from diverse fermented food and other environments showed abundant synonymous and non-synonymous nucleotide diversity, mostly driven by low frequency changes, distributed throughout the coding regions for all genes in both species. GAD genes showed higher level of replacement polymorphism compared to transporter genes (gadC and YjeM) for both species, and GAD genes that are outside of an operon structure showed even higher level of replacement polymorphism. Population genetic tests suggest negative selection against replacement changes in all genes. Molecular structure and amino acid characteristics analyses showed that in none of the GDP genes replacement changes alter 3D structure or charge distribution supporting negative selection against non-conservative amino acid changes. Phylogenetic and between species divergence analyses suggested adaptive protein evolution on GDP genes comparing phylogenetically distant species, but conservative evolution comparing closely related species. GDP genes within an operon structure showed slower molecular evolution and higher conservation. All GAD and transporter genes showed high codon usage bias in examined LAB species suggesting high expression and utilization of acid resistance genes. Substantial discordances between species, GAD, and transporter gene tree topologies were observed suggesting molecular evolution of GDP genes do not follow speciation events. Distribution of operon structure on the species tree suggested multiple independent gain or loss of operon structure in LABs. In conclusion, GDP genes in LABs exhibit a dynamic molecular evolutionary history shaped by gene loss, gene transfer, negative and positive selection to maintain its active role in acid resistance mechanism, and enable organisms to thrive in acidic environments.

Update of the Pyrrolysyl-tRNA Synthetase/tRNAPyl Pair and Derivatives for Genetic Code Expansion.

The cotranslational incorporation of pyrrolysine (Pyl), the 22nd proteinogenic amino acid, into proteins in response to the UAG stop codon represents an outstanding example of natural genetic code expansion. Genetic encoding of Pyl is conducted by the pyrrolysyl-tRNA synthetase (PylRS) and its cognate tRNA, tRNAPyl. Owing to the high tolerance of PylRS toward diverse amino acid substrates and great orthogonality in various model organisms, the PylRS/tRNAPyl-derived pairs are ideal for genetic code expansion to insert noncanonical amino acids (ncAAs) into proteins of interest. Since the discovery of cellular components involved in the biosynthesis and genetic encoding of Pyl, synthetic biologists have been enthusiastic about engineering PylRS/tRNAPyl-derived pairs to rewrite the genetic code of living cells. Recently, considerable progress has been made in understanding the molecular phylogeny, biochemical properties, and structural features of the PylRS/tRNAPyl pair, guiding its further engineering and optimization. In this review, we cover the basic and updated knowledge of the PylRS/tRNAPyl pair's unique characteristics that make it an outstanding tool for reprogramming the genetic code. In addition, we summarize the recent efforts to create efficient and (mutually) orthogonal PylRS/tRNAPyl-derived pairs for incorporation of diverse ncAAs by genome mining, rational design, and advanced directed evolution methods.

Starch Chemical Composition and Molecular Structure in Relation to Physicochemical Characteristics and Resistant Starch Content of Four Thai Commercial Rice Cultivars Differing in Pasting Properties.

Variations in starch pasting properties, considered an alternative potential quality classification parameter for rice starches, are directly controlled by the diverse starch molecular composition and structural features. Here, the starch characteristics of four rice cultivars (i.e., RD57, RD29, KDML105, and RD6) differing in pasting properties were assessed, and their relationship was determined. The results revealed that protein and moisture contents and their crystalline type were similar among the four rice starches. However, their molecular compositions and structures (i.e., reducing sugar and amylose contents, amylopectin branch chain-length distributions, granule size and size distribution, and degree of crystallinity) significantly varied among different genotypes, which resulted in distinct swelling, solubility, gelatinization, retrogradation, and hydrolytic resistance properties. The swelling power and gelatinization enthalpy (∆H) were positively correlated with C-type granule and relative crystallinity, but were negatively correlated with amylose content, B-type granule and median particle size (d(0.5)). Conversely, the water solubility and resistant starch content negatively correlated with C-type granule, but positively correlated with amylose content, B-type granule, and d(0.5). The gelatinization onset temperature (To(g)), and retrogradation concluding temperatures (Tc(r)), enthalpy (∆H(r)), and percentage (R%) were positively impacted by the amount of protein, amylose, and B1 chains (DP 13-24), while they were negatively correlated with short A chains (DP 6-12). Collectively, the starch physicochemical and functional properties of these Thai rice starches are attributed to an interplay between compositional and structural features. These results provide decisive and crucial information on rice cultivars' suitability for consumption as cooked rice and for specific industrial applications.

Ferroptosis-modulating small molecules for targeting drug-resistant cancer: Challenges and opportunities in manipulating redox signaling.

Ferroptosis is an iron-dependent cell death program that is characterized by excessive lipid peroxidation. Triggering ferroptosis has been proposed as a promising strategy to fight cancer and overcome drug resistance in antitumor therapy. Understanding the molecular interactions and structural features of ferroptosis-inducing compounds might therefore open the door to efficient pharmacological strategies against aggressive, metastatic, and therapy-resistant cancer. We here summarize the molecular mechanisms and structural requirements of ferroptosis-inducing small molecules that target central players in ferroptosis. Focus is placed on (i) glutathione peroxidase (GPX) 4, the only GPX isoenzyme that detoxifies complex membrane-bound lipid hydroperoxides, (ii) the cystine/glutamate antiporter system Xc - that is central for glutathione regeneration, (iii) the redox-protective transcription factor nuclear factor erythroid 2-related factor (NRF2), and (iv) GPX4 repression in combination with induced heme degradation via heme oxygenase-1. We deduce common features for efficient ferroptotic activity and highlight challenges in drug development. Moreover, we critically discuss the potential of natural products as ferroptosis-inducing lead structures and provide a comprehensive overview of structurally diverse biogenic and bioinspired small molecules that trigger ferroptosis via iron oxidation, inhibition of the thioredoxin/thioredoxin reductase system or less defined modes of action.

Vibrational Molecular Spectroscopy as a Tool to Study Molecular Structure Features of Cool-Season Chickpeas Impacted by Varieties and Thermal Processing in Relation to Nutrient Availability in Ruminants.

To our knowledge, there is no study on the relationship between molecular spectral features and nutrient availability in chickpeas. The purpose of this study was to reveal molecular structure spectral profiles among cool-season adapted CDC chickpea varieties and detect the molecular structure changes induced by thermal processing methods using vibrational Fourier-transform infrared (FTIR) spectroscopy. Three varieties of chickpea samples (CDC Alma, Cory, Frontier) were finely ground using a 0.12 mm screen. Spectral analyses were conducted using a JASCO FTIR-4200 spectroscope with Spectra Manager II software in the mid-infrared region from ca. 4000-800 cm-1 with a 4 cm-1 resolution. Data were analyzed using the "Mixed" procedure of SAS 9.4. Multiple regression was performed with PROC REG analysis for variable selection. Results showed that amide I area was higher (p = 0.038) in CDC Frontier than CDC Cory (30.85 vs. 24.64 AU). Amide I peak height (p = 0.028) was also higher in CDC Frontier and CDC Alma (0.45 AU in both) than CDC Cory (0.36 AU). Cellulosic compound (CEC) to total CHO (TCHO) area ratio was higher in CDC Frontier (0.05 AU) than the other two varieties (0.14 AU in both). As to thermal treatment impact, the results showed that total amide area was higher (p = 0.013) with autoclave and microwave heating (47.38 and 45.19 AU, respectively) than dry heating (33.06 AU). The CEC area was also higher (p &lt; 0.001) for autoclave and microwave heating (3.74 and 3.61 AU, respectively) than dry heating (2.20 AU). Moreover, the ratio of amide I to II height was higher (p = 0.022) with microwave heating than dry heating (1.44 vs. 1.16 AU, respectively). Relationship analysis showed that the effective degraded crude protein (EDCP) and bypass dry matter (% BDM) were associated with STCHO peaks and CEC height (p &lt; 0.05, R2 = 0.68). Also, feed milk value (FMVDVE) was associated with STC1, STC_A, and CEC_A (p &lt; 0.05, R2 = 0.85). In conclusion, vibrational molecular spectroscopy mid-infrared FTIR was able to reveal different molecular spectral characteristics among the cool-season adapted CDC chickpea varieties and detect molecular structure changes induced by thermal processing (dry heating, autoclaving, and microwave heating).

Fractionation of lignin from rice straw using an acidified biphasic solvent system

To obtain lignin from lignocellulosic biomass, phenoxyethanol (EPH) was employed to construct a biphasic solvent system. The concentration of EPH in this biphasic solvent system was first studied to determine a pretreatment condition for fractionation of lignin. Then, the fractionation of lignin from rice straw was performed under the conditions of temperature 130 °C, cooking time 60 min and sulfuric acid concentration 0.1 M, in 70 % aqueous EPH solvent system. The results showed that 50.97 %, 49.52 % or 82.02 % of the removed lignin with the purity of 89.04 %, 91.30 % or 84.76 % was regenerated from EPH liquor using dimethyl carbonate (DMC), dimethoxymethane (DMM) or diethyl ether (DE) as precipitant, respectively. Additionally, the weight-average molecular weight (Mw) and dispersity index (Đ) of the regenerated lignin decreased to 4247–4809 g/mol and 1.26–1.60 compared with that of the original lignin (5654 g/mol and 4.78). Finally, the compositional and structural characteristics of lignin, e.g., molecular weight and molecular structure, were also investigated by DSC, HSQC and elemental analysis.

Molecular Persistent Room-Temperature Phosphorescence from Tetraarylaminoboranes

Herein, we report the synthesis, molecular structure, and optical features of tetrarylaminoboranes 1 (Mes2B-N(Ph)(C10H7)) and 2 (Mes2B-N(Ph)(C14H9)). In the solution state, 1 shows aggregation-induced emission enhancement and color switching, while 2 displays emission color switching and aggregation-caused quenching. At 77 K, frozen solutions of 1 show delayed fluorescence (DF) and phosphorescence, whereas 2 display only DF. Pristine solids of 1 and 2 showed delayed fluorescence under ambient conditions; however, crystals of both compounds show no phosphorescence under similar conditions. Polymethyl methacrylate thin films of 1 (1 wt % doping concentration) exhibit persistent room-temperature phosphorescence (pRTP) lasting for ∼0.5 s. In contrast, 2 does not show phosphorescence under similar conditions. Systematic photophysical studies and theoretical (DFT and TD-DFT) calculations are performed on these molecules to rationalize their intriguing optical characteristics.

Quantitative structure-activity relationship for the photooxidation of aromatic micro-pollutants induced by graphene oxide in water

The photocatalytic degradation behavior of aromatic micro-pollutants (AMPs) exhibits complexity and uncertainty, which mainly depends on the properties of different substituents on benzene. And with similar catalytic reaction substrates, the reaction rate constant could reveal the influence of different characteristics of molecular structure in a specific system. Therefore, the photooxidation pseudo first-order kinetic rate constants (kobs) of 30 AMPs were experimentally determined in Photo-GO system. A quantitative structure-activity relationship (QSAR) model for predicting the photooxidation reaction of AMPs has been developed by stepwise multiple linear regression (MLR) method, based on the lg kobs and representative molecule descriptors (20 in total) including physicochemical, quantum chemical and electrostatic descriptors. Afterwards, Radj2, QLOO2, and Qext2 were calculated as 0.870, 0.841, and 0.732 respectively, which exhibited the excellent goodness-of-fit, robustness, and predictability of the QSAR model, indicating its great prediction ability for photooxidation behavior of AMPs. Meanwhile, during the photooxidation process of AMPs with GO, the model revealed that the one-electron oxidation potential (Eox), molecular dipole moment (μ), and number of hydrogen bond donors (#HD) were the most important molecular structural parameters, which showed that the single electron transfer pathway and adsorption were as the significant steps. Additionally, the Hammett correlation showed that photooxidation of AMPs in Photo-GO system is of typical electrophilic reactions, which demonstrated that the electron-donating substituents could promote the photooxidation of AMPs. The QSAR model was constructed and evaluated to perform the prediction of AMPs reaction kinetics, which provided a guidance for the study of the mechanism and selective oxidation of AOPs photooxidation system based on GO.

Mechanism of heat‐induced thinning of thick egg white in weak alkaline condition: molecular aggregation, functional and structure properties analysis

SummaryThe thinning of thick egg white (KEW) was simulated by weak alkaline (pH 10.0) combined with mild heat (50 °C) treatment. The molecular aggregation, functional and structural characteristics changes in simulated KEW thinning process were comprehensively studied. It was found that KEW molecule entered “molten pellet (MG)” state with decline of apparent viscosity of KEW. At this time, particle size increased by 40.9%, surface hydrophobicity and solubility declined 11.3% and 8.9%, respectively. However, with more mild heating time, KEW structure gradually unfolded, ovomucin (OVM) degraded, particle size diminished significantly. Surface hydrophobicity and solubility increased 6.6% and 19.7%, respectively. Functional properties indicated that thermal gel of KEW gradually became soft and tough, water holding capacity (WHC) advanced by 10%, emulsifying property significantly improved by 40%. Moreover, correlation analysis indicated that tertiary structure was correlated with particle size (P &lt; 0.01), secondary structure related to hardness and WHC (P &lt; 0.05). Through the results of SDS‐PAGE and comparison with KEW simple mild heating, it was concluded that rise of pH was intrinsic driving force of KEW thinning. Therefore, this study provided a new insight for revealing the thinning mechanism of KEW and a scientific basis for its industrial application.

Synthesis of amantadine clubbed N-aryl amino thiazoles as potent urease, α-amylase & α-glucosidase inhibitors, kinetic and molecular docking studies.

A series of ten novel compounds were synthesized by incorporating a 1,3 thiazole core into amantadine and their structures were validated using different analytical and spectral methods such as FTIR, EI-MS, 1H NMR, and 13C NMR. The antibacterial and enzyme inhibitory properties of these newly synthesized compounds were evaluated. Remarkably, the compounds exhibited significant antibacterial activity against Escherichia coli and Bacillus subtilis. Additionally, the in vitro inhibitory activities of the synthesized compounds, against α-amylase, α-glucosidase, and urease were investigated. Among the tested compounds, compound 6d demonstrated potent and selective inhibition of α-amylase IC50 = 97.37 ± 1.52 μM, while acarbose was used as positive control and exhibited IC50 = 5.17 ± 0.25 μM. Compound 6d and 6e exhibited prominent inhibition against α-glucosidase IC50 = 38.73 ± 0.80 μM and 41.63 ± 0.26 μM respectively. Furthermore, compound 6d inhibited urease with exceptional efficacy IC50 = 32.76 μM, while positive control thiourea showed more prominent activity having IC50 = 1.334 μM. Molecular docking studies disclosed the binding mechanism and affinity of these new inhibitors within the binding sites of various amino acids. To investigate the association between molecular structural characteristics and inhibitory actions of synthesized derivatives, preliminary structure-activity relationship (SAR) studies were performed. These findings indicated that compounds 6a, 6c, 6d and 6e are potential candidates for hit-to-lead follow-up in the drug-discovery process for treating diabetes and hyperglycemia.

Changes in interfacial composition and structure of milk fat globules are crucial regulating lipid digestion in simulated in-vitro infant gastrointestinal digestion

The interfacial phospholipid and protein compositions of fat globule in human milk and three different infant formulas (F1: supplied with MFGM and OPO; F2: supplied with OPO and without MFGM; F3: supplied with MFGM and without OPO) were analyzed and compared, and the changes of interfacial composition and structure on their in-vitro infant gastrointestinal digestion were evaluated. The study from the interfacial properties of fat globule to illustrating the effect of interfacial composition and structure on lipolysis and proteolysis. The results showed that, both F1 and human milk had a similar interfacial phospholipid composition and higher sphingomyelin (SM) content. The interfacial protein composition of F1 was closer to human milk. F1 had the average particle size of 3.67 ± 0.12 μm and a phospholipid layer on the surface of triglyceride. Meanwhile, the relatively complete phospholipid ring structure in F1 could always be observed during gastric digestion, while was gradually destroyed during intestinal digestion. Moreover, F2 and F3 are significantly different from HM and F1 in composition and structure of fat globule. Although MFGM is added to commercial infant formula (F3), most MFGM still existed in the aqueous phase of emulsion in free form. Notable, F1 had similar in-vitro lipolysis and proteolysis properties to human milk. These results indicated that the simulation of human milk fat globule at the molecular level and structure feature was the key contributing to digestion behavior. • The abundant phospholipid ring structure were observed in F1. • F1 had sn-2 SFAs and OPO, which reduced the formation of calcium soap. • HM had the highest lipolysis rate of 86.3%, followed by F1 (82.9%) after digestion. • F1 had similar digestive properties to human milk and is superior to F2 and F3. • The simulation of HM fat at the molecular and structure is key to effect digestion.