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Two new complexes of nickel(II) benzoylhydrazone 2-(N-tosylamino)benzaldehyde (H2L) with additional heterocyclic donor ligands L1 = 2,2′-bipyridine and L2 = 1,10-phenanthroline are synthesized. Structures and compositions of the obtained compounds are determined by elemental analysis, 1H NMR, and IR techniques. Crystal and molecular structures of the Ni(II) complexes are determined by single crystal X-ray diffraction. The adducts are shown to have dimeric structures: Ni2L2L1(CH3OH) and Ni2L2L2(CH3OH). In both adducts, one of nickel(II) ions is in a distorted square-planar environment while another is in the octahedral environment due to additional coordination of 2,2′-bipyridine or 1,10-phenanthroline and a methanol molecule. The biological activity of the complexes is studied. It is found that both adducts exhibit the protistocidal activity against Colpoda steinii, with Ni2L2L1(CH3OH) being twice less active and Ni2L2L2(CH3OH) being twice more active than the chloroquine reference. [ABSTRACT FROM AUTHOR]

This study presents a comprehensive structural analysis of the adducts formed upon the reaction of two Ru(III) complexes [HIsq][trans-RuIIICl4(dmso)(Isq)] (1) and [H2Ind][trans-RuIIICl4(dmso)(HInd)] (2) (where HInd-indazole, Isq-isoquinoline, analogs of NAMI-A) and two Ru(II) complexes, cis-[RuCl2(dmso)4] (c) and trans-[RuCl2(dmso)4] (t), with hen-egg white lysozyme (HEWL). Additionally, the crystal structure of an adduct of human lysozyme (HL) with ruthenium complex, [H2Ind][trans-RuCl4(dmso)(HInd)] was solved. X-ray crystallographic data analysis revealed that all studied Ru complexes, regardless of coordination surroundings and metal center charge, coordinate to the same amino acids (His15, Arg14, and Asp101) of HEWL, losing most of their original ligands. In the case of the 2-HL adduct, two distinct metalation sites: (i) Arg107, Arg113 and (ii) Gln127, Gln129, were identified. Crystallographic data were supported by studies of the interaction of 1 and 2 with HEWL in an aqueous solution. Hydrolytic stability studies revealed that both complexes 1 and 2 liberate the N-heterocyclic ligand under crystallization-like conditions (pH 4.5) as well as under physiological pH conditions, and this process is not significantly affected by the presence of HEWL. A comparative examination of nine crystal structures of Ru complexes with lysozyme, obtained through soaking and co-crystallization experiments, together with in-solution studies of the interaction between 1 and 2 with HEWL, indicates that the hydrolytic release of the N-heterocyclic ligand is one of the critical factors in the interaction between Ru complexes and lysozyme. This understanding is crucial in shedding light on the tendency of Ru complexes to target diverse metalation sites during the formation and in the final forms of the adducts with proteins. [ABSTRACT FROM AUTHOR]

Large natural magnesium resources, consisting primarily of magnesium chloride hexahydrate, are being wasted and not used efficiently in certain areas of the world. With the shortage of aluminum and iron resources, the transformation of natural magnesium resources into products has become a challenging task. Ethanol, a lower, saturated monohydric aliphatic alcohol known for being green, non-toxicity, and capable of dissolving magnesium chloride hexahydrate, offers a potential solution. This paper focuses on introducing magnesium chloride hexahydrate into ethanol and investigating the recovered samples from the magnesium chloride-ethanol solution by isothermal evaporation at different temperatures, to explore the possibility of extracting magnesium chloride hexahydrate from magnesium salt minerals using ethanol. Results showed that magnesium chloride hexahydrate can be completely recovered at 130 °C. The composition of the recovered sample is mainly magnesium chloride hexahydrate. The good thermal stability is due to high crystallinity and the existence of a strong coordination bond of ethanol in the magnesium chloride crystal structure. All recovered samples have a high current density in ethanol. This research shows that introducing magnesium salt minerals into ethanol to extract magnesium chloride hexahydrate can be a viable option for recycling natural magnesium resources. [ABSTRACT FROM AUTHOR]

Epigallocatechin-3-gallate (EGCG), a prominent polyphenol found abundantly in tea, has garnered significant attention for its potential in preventing and ameliorating a wide range of diseases. Its remarkable antioxidant properties and ability to capture reactive carbonyl species make it a key player among tea's polyphenolic components. This paper delves into the synthesis and origins of both EGCG and reactive carbonyl species (RCS), emphasizing the toxicity of RCS in various food sources and their formation during food processing. Understanding EGCG's capability to capture and metabolize RCS is crucial for harnessing its health benefits. Thus, this paper explores the underlying mechanisms of EGCG for RCS inhibition and its role in capturing these compounds to generate EGCG-RCS adducts. And the absorption and metabolism of EGCG-RCS adducts is also discussed. [ABSTRACT FROM AUTHOR]

This study presents a comprehensive structural analysis of the adducts formed upon the reaction of two Ru(III) complexes [HIsq][trans-RuIIICl4(dmso)(Isq)] (1) and [H2Ind][trans-RuIIICl4(dmso)(HInd)] (2) (where HInd–indazole, Isq–isoquinoline, analogs of NAMI-A) and two Ru(II) complexes, cis-[RuCl2(dmso)4] (c) and trans-[RuCl2(dmso)4] (t), with hen-egg white lysozyme (HEWL). Additionally, the crystal structure of an adduct of human lysozyme (HL) with ruthenium complex, [H2Ind][trans-RuCl4(dmso)(HInd)] was solved. X-ray crystallographic data analysis revealed that all studied Ru complexes, regardless of coordination surroundings and metal center charge, coordinate to the same amino acids (His15, Arg14, and Asp101) of HEWL, losing most of their original ligands. In the case of the 2-HL adduct, two distinct metalation sites: (i) Arg107, Arg113 and (ii) Gln127, Gln129, were identified. Crystallographic data were supported by studies of the interaction of 1 and 2 with HEWL in an aqueous solution. Hydrolytic stability studies revealed that both complexes 1 and 2 liberate the N-heterocyclic ligand under crystallization-like conditions (pH 4.5) as well as under physiological pH conditions, and this process is not significantly affected by the presence of HEWL. A comparative examination of nine crystal structures of Ru complexes with lysozyme, obtained through soaking and co-crystallization experiments, together with in-solution studies of the interaction between 1 and 2 with HEWL, indicates that the hydrolytic release of the N-heterocyclic ligand is one of the critical factors in the interaction between Ru complexes and lysozyme. This understanding is crucial in shedding light on the tendency of Ru complexes to target diverse metalation sites during the formation and in the final forms of the adducts with proteins.

The competition between the ytterbium endo‐atom and the pyridine exo‐molecules as nucleophiles interacting with the electron‐deficient 1H,4H‐1,4‐diborabuckminsterfullerene was studied using the quantum chemical DFT PBE0 method. The equilibrium structural parameters, dipole moments, IR spectra, and exothermic effects of the formation of the C58B2•Py2 adduct and the endohedral Yb@C58B2•Py2 complex were determined. The concept of the state of oxidation/reduction of an atom in a chemical compound has been clarified. The localization of the ytterbium(II) under a pair of equivalent carbon atoms bonded to boron(III) atoms is predicted. The introduction of ytterbium(II) into the adduct cavity weakens exo‐bonds with pyridine molecules without changing the oxidation state of boron(III). Each nitrogen atom retains a lone electron pair, coordinated by a boron(III). The ytterbium(II) endo‐atom retains 14 electrons in f states. [ABSTRACT FROM AUTHOR]

The aim of this work is to investigate the influence of the ethanol content of adducts on the catalytic behavior of related Ziegler–Natta (ZN) catalysts in propylene homo- and copolymerizations (with 1-hexene comonomer) in terms of activity, isotacticity, H2 response, and comonomer incorporation. For this purpose, three MgCl2.nEtOH adducts with n values of 0.7, 1.2, and 2.8 were synthesized and used in the synthesis of related ZN catalysts. The catalysts were thoroughly characterized using XRD, BET, SEM, EDX, N2 adsorption–desorption, and DFT techniques. Additionally, the microstructure of the synthesized (co)polymers was distinguished via DSC, SSA, and TREF techniques. Their activity was found to enhance with the adduct's ethanol content in both homo- and copolymerization experiments, and the increase was more pronounced in homopolymerization reactions in the absence of H2. Furthermore, the catalyst with the highest ethanol content provided a copolymer with a lower isotacticity index, a shorter meso sequence length, and a more uniform distribution of comonomer within the chains. These results were attributed to the higher total surface area and Ti content of the corresponding catalyst, as well as its lower average pore diameter, a larger proportion of large pores compared to the other two catalysts, and its spherical open bud morphology. It affirms the importance of catalyst/support ethanol-content control during the preparation process. Then, molecular simulation was employed to shed light on the iso-specificity of the polypropylene produced via synthesized catalysts. [ABSTRACT FROM AUTHOR]

Stable N‐heterocyclic carbenes (NHCs) have garnered significant attention in synthetic chemistry due to their versatile applications. In this study, we explored a novel mechanochemical method for the generation of free carbenes, which could be a good complement to traditional approaches that require strong bases or reductants. Ball milling of NHC–CS2 adducts at room temperature successfully resulted in the quantitative formation of free carbenes that can be subsequently trapped by sulfur or selenium. Importantly, heating NHC–CS2 adducts in solution phase did not lead to the successful generation of free carbenes, in agreement with the high activation energy required for NHC–CS2 dissociation. These findings underscore the potential of ball milling as a robust and versatile approach for generating NHCs from stable NHC‐small molecule adducts, and opens new avenues for developing mechanochemical strategies for generating valuable NHC‐derived compounds. [ABSTRACT FROM AUTHOR]

This article describes the synthesis of fullerenol— C 60 (O H) 24 adducts with some heavy metals— C 60 (O N a) x (O 2 M e) (24 − x) / 2 ; C 60 (O N a) x (O 3 M e) (24 − x) / 3 ; Me=Co; Cu; Mn; Zn; Gd; Tb. The identification of adducts was carried out by the methods of: elemental analysis, infrared and electronic spectroscopy, complex thermal analysis, high-performance liquid chromatography and dynamic light scattering. The solubility of adducts in aqueous solutions in the ambient temperature range has been studied. The solubility was significant and ranged from a few tenths to 1 g/dm3. The use of these adducts as micronutrients for spring barley crops in the Republic of Kazakhstan is considered. When using these nanopreparations, a general increase in yield (tens, up to 80 rel.%), nutrient content and moisture content of seeds (4–5 rel. mass %), as well as the resistance of the latter to the effects of pathogenic microorganisms (percentage of healthy seeds growth up to 10 rel.%), was noted. [ABSTRACT FROM AUTHOR]

Tobacco use is a major cause of preventable morbidity and mortality globally. Tobacco products, including smokeless tobacco (ST), generally contain tobacco-specific N-nitrosamines (TSNAs), such as N′-nitrosonornicotine (NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-butanone (NNK), which are potent carcinogens that cause mutations in critical genes in human DNA. This review covers the series of biochemical and chemical transformations, related to TSNAs, leading from tobacco cultivation to cancer initiation. A key aim of this review is to provide a greater understanding of TSNAs: their precursors, the microbial and chemical mechanisms that contribute to their formation in ST, their mutagenicity leading to cancer due to ST use, and potential means of lowering TSNA levels in tobacco products. TSNAs are not present in harvested tobacco but can form due to nitrosating agents reacting with tobacco alkaloids present in tobacco during certain types of curing. TSNAs can also form during or following ST production when certain microorganisms perform nitrate metabolism, with dissimilatory nitrate reductases converting nitrate to nitrite that is then released into tobacco and reacts chemically with tobacco alkaloids. When ST usage occurs, TSNAs are absorbed and metabolized to reactive compounds that form DNA adducts leading to mutations in critical target genes, including the RAS oncogenes and the p53 tumor suppressor gene. DNA repair mechanisms remove most adducts induced by carcinogens, thus preventing many but not all mutations. Lastly, because TSNAs and other agents cause cancer, previously documented strategies for lowering their levels in ST products are discussed, including using tobacco with lower nornicotine levels, pasteurization and other means of eliminating microorganisms, omitting fermentation and fire-curing, refrigerating ST products, and including nitrite scavenging chemicals as ST ingredients. [ABSTRACT FROM AUTHOR]

The paraffin–naphthenic fractions (with boiling points below 310°C) prepared from three high-viscosity naphthenic crude oils, classified as types B1 and B2 (according to Petrov's classification), were subjected to thiocarbamide complexation. The molecular composition of polycyclic hydrocarbon biomarkers and C11–C13 adamantanes in the oil samples suggested a predominantly marine genotype of the precursor organic matter (OM). The molecular composition also suggested source rocks of a clayey type. Nonetheless, the biomarkers detected in one sample indicated some contribution of terrigenous components to the precursor OM. All the oils were generated under the conditions of the main oil generation zone and, presumably, underwent microbial transformations in the deposits. The compositions of C10–C14 adamantanes in the initial paraffin–naphthenic fraction, in the thiocarbamide adduct, and in the filtrate that remained after the adduction were comparatively characterized for each oil sample. The test conditions allowed us to have adamantane more than 100-fold concentrated (in the adduct), to quantify it in the oils, and to evaluate the concentrations of C11–C14 alkyladamantanes in the oils using adamantane as an internal standard. C10–C14 adamantanes exhibited selective adduction ability, with the extraction ratios of individual components being different. Taking into account these extraction ratios, the component concentrations were evaluated on crude oil basis: 2.7 to 7.6×10–3 wt % for adamantane and 87 to 267×10–3 wt % for total C10–C14 adamantanes. The identification of adamantanes in the initial paraffin–naphthenic fractions, adducts, and filtrates revealed the presence of some other tricyclanes (probable precursors of alkyladamantanes) as well as decaline homologues. Like adamantanes, these compounds exhibited selective ability to complex with thiocarbamide. [ABSTRACT FROM AUTHOR]

Organophosphorus chemical agents are included in the 1st List of the Annex on Chemicals of the Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on Their Destruction (Chemical Weapons Convention, CWC). For the purposes of verification of compliance with the provisions of the CWC, special methods, which are considered the most informative at determining the retrospective effects of organophosphorus toxicants on the body, are necessary. Typical long-lived biomarkers of organophosphate toxic agents are tyrosine phosphorylation products, the presence of which in biomedical samples clearly indicates the exposure to sarin, soman, tabun and V-series agents. We have elaborated methods for the synthesis and isolation of tyrosine adducts derivatives of methylphosphonic and phosphoric acids, used as reference samples. The synthesis scheme included the consecutive protection of carboxyl and amino groups of tyrosine, its O-phosphorylation by the corresponding alkylphosphonates and phosphates, the removal of protective groups with the release of corresponding O-phosphorylated tyrosine adducts. Their purification from impurities was carried out, using column chromatography (SiO2, eluent: dichloromethane/ethyl acetate 1:1). The purity of the obtained products was more than 90 %, so it was possible to involve them in further transformations with the use of catalyst without the threat of its «poisoning». Benzyl and carboxybenzyl protection of phosphorylated L-tyrosines (12–17) was removed by means of catalytic hydrogenation by molecular hydrogen under atmospheric pressure. Target adducts of phosphorylated reagents and L-tyrosin were obtained (63–82 %) in form of crystal white substances, readily soluble in water and ethanol, and poorly – in dichloromethane and acetonitrile.

Hypothesis: Some adducts were prepared from three kinds of DGEBA-based epoxy resins, phthalic anhydride and an alkanol amine accelerator, as a latent accelerator for one-pot epoxy/dicy systems. These adducts come with two kinds of accelerators: DMP-30 A, which is lab-grade and Ax-10, which is industrial-grade, as well as DGEBA based epoxy resins Epikote 828, Epiran 06 and ML 504. The adduct made of Epikote 828 and DMP-30 A was considered as a reference. It seems that it might be possible to prepare a new efficient latent accelerator with change of epoxy resin and accelerator.Methods: For this purpose, four different adducts with resins and accelerators and four different epoxy/dicy mixtures with four adduct types and AX-10 accelerator and one with no adduct as a reference were prepared. Measuring the melting point, viscosity build-up versus time, gelation time, non-isothermal differential scanning calorimetry (DSC) and glass transition temperature characterization and also lap shear, interlaminar shear strength, transvers tensile and scanning electron microscope (SEM) were used to study the latent properties of the prepared adducts in the epoxy/dicy system and find its effect on mechanical properties of the final composites and all were compared with references.Findings: Melting point of all adducts is above room temperature, so they are solid at room temperature. The results show that the adducts containing the industrial accelerator in one-pot epoxy/dicy system has lower gel time at high temperature, higher viscosity changes at ambient temperature and pot life and has made no significant change in cure temperature. The mechanical properties of the composite made with an adduct consisting of ML 504 resin are accompanied by a decrease in the related values. In general, the adduct made with Epiran 06 or Epikote 828 resin and industrial accelerator is an efficient and new latent accelerator and is suitable for preparing one-pot epoxy/dicy systems.

The structure of K5(HPO4)2(H2PO4)·H2O was determined via single crystal diffraction. The crystal structures of phosphate salts of potassium have been known since the early days of crystallography. Here, we present a new monohydrate adduct between K2HPO4 and KH2PO4. [ABSTRACT FROM AUTHOR]

L-cysteine can significantly reduce the content of acrylamide and form new substances. To clarify the reduction mechanism and apply it in potato chip processing, a high purity cysteine-acrylamide adduct was prepared. The target adduct was synthesized by optimizing the reaction conditions, followed by reversed-phase column chromatography for separation and purification. Its structure was identified by mass spectrometry, nuclear magnetic resonance and ultraviolet spectroscopy, and the reduction mechanism was correspondingly elucidated. The cytotoxicity of adducts was evaluated with Caco-2 cell line. Furthermore, potato chips were pretreated with cysteine solutions and the reduction of acrylamide was detected by UPLC-MS. The results showed that the adduct with 95% purity could be obtained when the optimum reaction ratio of cysteine and acrylamide was 1:3 at 120 ℃ for 3 h. Its molecular formula was C6H9NO3S, with relative molecular weight of 192.0641 and maximum UV absorption wavelength of 196 nm. It was formed by Michael addition reaction between the sulfhydryl group of cysteine and the alkenyl group of acrylamide. Compared to acrylamide, the cytotoxicity of the adduct was significantly lower after 24 and 48 h treatment. Potato chips soaked in cysteine solutions of 3 and 5 g/L before frying obtained over 83% of acrylamide reduction rate. In addition, a certain amount of adduct was detected in such potato chips, indicating that cysteine could significantly reduce the acrylamide content in fried potato chips by forming acrylamide adduct.

Here, it is aimed to clarify the structure‐performance relationship in MgCl2 based Ziegler Natta catalysts toward ethylene polymerizations. In this regard, 11 different adduct precursors were prepared through industrially appreciated melt quenching method employing various: (i) reaction times for dissolving magnesium chloride inside ethanol; (ii) ethanol/MgCl2 molar ratios in the feed; (iii) heating rates during thermal dealcoholation; (iv) N2 flows during thermal dealcoholation and (v) alcohol content after thermal dealcoholation. Among the studied parameters, heating rate and N2 flow during thermal dealcoholation have the most pronounced effect on the porosity and particle size of the resulted adducts. Related Ziegler Natta catalysts were subsequently employed in ethylene polymerizations. According to the kinetic curves, catalyst productivity and form of kinetic curve (as decay or build‐up type) can be precisely tailored by proper choosing of the mentioned variables during adduct synthesis. Microstructure analysis of the prepared polyethylenes reveals that alcohol content in the final adduct has the most significant effect on the H2 response, in terms of molar mass and its distribution, of the related Ziegler Natta catalysts. The overall results help polyethylene producers in choosing proper reaction conditions during adduct synthesis for the production of different polymer grades, when productivity or H2 response is targeted. [ABSTRACT FROM AUTHOR]

Recently, non‐Faradaic effects were used to modify the electronic structure and reactivity of electrode‐bound species. We hypothesize that these electrostatic perturbations could influence the chemical reactivity of electrolyte species near an electrode in the absence of Faradaic electron transfer. A prime example of non‐Faradaic effects is acid‐base dissociation near an interface. Here, we probed the near‐electrode dissociation of N‐heterocycle‐BF3 Lewis adducts upon electrode polarization, well outside of the redox potential window of the adducts. Using scanning electrochemical microscopy and confocal fluorescence spectroscopy, we detected a potential‐dependent depletion of the adduct near the electrode. We propose an electro‐inductive effect where a more positive potential leads to electron withdrawal on the N‐heterocycle. This study takes a step forward in the use of electrostatics at electrochemical interfaces for field‐driven electrocatalytic and electro‐synthetic processes. [ABSTRACT FROM AUTHOR]

The structure of K5(HPO4)2(H2PO4)·H2O was determined via single crystal diffraction. The crystal structures of phosphate salts of potassium have been known since the early days of crystallography. Here, we present a new monohydrate adduct between K2HPO4 and KH2PO4.

Epigallocatechin-3-gallate (EGCG), a prominent polyphenol found abundantly in tea, has garnered significant attention for its potential in preventing and ameliorating a wide range of diseases. Its remarkable antioxidant properties and ability to capture reactive carbonyl species make it a key player among tea’s polyphenolic components. This paper delves into the synthesis and origins of both EGCG and reactive carbonyl species (RCS), emphasizing the toxicity of RCS in various food sources and their formation during food processing. Understanding EGCG’s capability to capture and metabolize RCS is crucial for harnessing its health benefits. Thus, this paper explores the underlying mechanisms of EGCG for RCS inhibition and its role in capturing these compounds to generate EGCG-RCS adducts. And the absorption and metabolism of EGCG-RCS adducts is also discussed.

The Diels-Alder reaction involves cycloaddition of dienes and dienophiles to form a six-membered ring. The reaction involves the formation of adduct which can have two possible configurations, viz, endo and exo. For a vast majority of the Diels-Alder reactions, endo is the major adduct. This first ever study focuses on the Diels-Alder reaction between dibenzazepine and 2,5-dimethylfuran depicted by the computational method using Gaussian 16 software at different basis set levels. The formation of adduct is studied under different temperatures in the gas phase and aqueous medium. The kinetically favored endo adduct is preferred at low temperatures as compared to exo adduct. The adduct gets dehydrated further to give tribenzazepine as the final product. The applicability of the reaction is also proved experimentally in absence or presence of aqueous medium. The final product is characterized and its experimental and theoretical 1HNMR are compared. [ABSTRACT FROM AUTHOR]

Cyclopropylamine borane C3H5NH2BH3 (C3AB), 2-ethyl-1-hexylamine borane CH3(CH2)3CH(C2H5)CH2NH2BH3 (C2C6AB) and didodecylamine borane (C12H25)2NHBH3 ((C12)2AB) are three new amine borane adducts (ABAs). They are synthesized by reaction of the corresponding amines with a borane complex, the reaction being exothermic as shown by Calvet calorimetry. The successful synthesis of each has been demonstrated by FTIR, Raman and NMR. For instance, the 11B NMR spectra show the presence of signals typical of the NBH3 environment, thereby implying the formation of B–N bonds. The occurrence of dihydrogen bonds (DHBs) for each of the ABAs has been highlighted by DSC and FTIR, and supported by DFT calculations (via the Mulliken charges for example). When heated, the three ABAs behave differently: C3AB and C2C6AB decompose from 68 to 100 °C whereas (C12)2AB is relatively stable up to 173 °C. That means that these ABAs are not appropriate as hydrogen carriers, but the 'most' stable (C12)2AB could open perspectives for the synthesis of advanced materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • One Cu-Dy 3d-4f adduct has been synthesized and characterized. • The Cu-Dy complex is a discrete system. • The Cu-Dy adduct exhibits a slowing down of magnetic relaxation under the external dc field. One discrete 3d-4f adduct with formula {[Cu(hfac)(Nit-PhCH 2 -PyN)]+[Dy(hfac) 4 ]–} (hfac=hexafluoroacetylacetonate, Nit-PhCH 2 -PyN=2-[4-[bi(2-pyridylmethyl)amine]-tolyl]-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) has been afforded on the basis of a one-pot process of Dy(hfac) 3 ·2H 2 O, Cu(hfac) 2 ·2H 2 O and a tridentate chelate ligand Nit-PhCH 2 -PyN. Interestingly, one discrete [Dy(hfac) 4 ]– anion and [Cu(hfac)(Nit-PhCH 2 -PyN)]+ serving as the counter-ion are present in the 3d-4f complex. In addition, magnetic studies have shown field-induced slow magnetic relaxation is derived from the [Dy(hfac) 4 ]– anion, involving the eight-coordinated DyIII ion with D 4d symmetry. [ABSTRACT FROM AUTHOR]

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A large part of the Human chemical exposome is now well characterized, and its health effects has been widely documented, although precise causal links remain difficult to establish. In parallel, genetic factors only were shown to contribute less than 30% to various pathologies. Therefore, environmental factors may represent the predominant cause of chronic diseases. Mass Spectrometry has been established for many years as a main "gold standard" in this field due to its performances both in sensitivity and selectivity. However, some unstable or highly reactive compounds may escape their detection in the biological samples because of their short half-life although some of their stable metabolites, if any, can be used for the exposure assessment. These electrophilic molecules are known to bind covalently to nucleophilic molecules in the body to form what are commonly called adducts. The study of adducts formed with DNA, proteins or with glutathione, nowadays called adductomics, can provide additional toxicologically relevant information in biomonitoring studies. This review describes this particular part of the reactive exposome and the related mass spectrometric methods developed therein. Three dedicated parts of this review are devoted to the contribution of mass spectrometry respectively to the assessment of DNA modifications, protein modifications, and reaction with glutathione., (© 2024 Wiley Periodicals LLC.)

Covalent protein adducts formed by drugs or their reactive metabolites are risk factors for adverse reactions, and inactivation of cytochrome P450 (CYP) enzymes. Characterization of drug-protein adducts is limited due to lack of methods identifying and quantifying covalent adducts in complex matrices. This study presents a workflow that combines data-dependent and data-independent acquisition (DDA and DIA) based liquid chromatography with tandem mass spectrometry (LC-MS/MS) to detect very low abundance adducts resulting from CYP mediated drug metabolism in human liver microsomes (HLMs). HLMs were incubated with raloxifene as a model compound and adducts were detected in 78 proteins, including CYP3A and CYP2C family enzymes. Experiments with recombinant CYP3A and CYP2C enzymes confirmed adduct formation in all CYPs tested, including CYPs not subject to time-dependent inhibition by raloxifene. These data suggest adducts can be benign. DIA analysis showed variable adduct abundance in many peptides between livers, but no concomitant decrease of unadducted peptides. This study sets a new standard for adduct detection in complex samples, offering insights into the human adductome resulting from reactive metabolite exposure. The methodology presented will aid mechanistic studies to identify, quantify and differentiate between adducts that result in adverse drug reactions and those that are benign.

The hydrosilylation reactions of allylsilanes R3SiAll (R = Cl3, Me3) with methylchlorohydridesilanes MenCl3–nSIH (n = 0–2) and symmetrical tetramethyldisiloxane in the presence of the Karstedt catalyst have been studied. It has been found that the change in reactivity of allylsilanes in these reactions has been similar to the allylgermanes, except for the reaction of allyltrichlorosilane with dimethylchlorosilane, probably due to lower electronegativity of the Cl3Si group as compared to the Cl3Ge group. The allylsilanes have shown higher reactivity in these reactions than the isostructural allylgermanes. A scheme of the possible course of the studied reactions has been proposed. The synthesized compounds have been identified using 1H NMR spectroscopy and chromatography–mass spectrometry. [ABSTRACT FROM AUTHOR]

The effect of acrolein on the formation of the 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) was investigated in a chemical model. Acrolein was found to increase PhIP formation at each tested addition level. 0–0.2 mmol of acrolein increased PhIP formation dose-dependently, while high levels of acrolein (>0.2 mmol) did not further increase PhIP formation. Mechanistic study showed that acrolein addition decreased the residue of phenylalanine and creatinine, but increased the content of some key intermediates. Further analysis indicated that acrolein can react with phenylalanine, creatinine, and PhIP to form adducts. These results suggested that acrolein was able to contribute to PhIP formation as a consequence of its comprehensive ability to facilitate Strecker degradation of phenylalanine and react with phenylalanine, creatinine, and PhIP. In addition, oxidation of the tilapia fish increased the PhIP formation in the roasted fish patties, further supporting the potential contribution role of lipid oxidation products to the formation of PhIP.

Acrylamide (AA) is a food contaminant, and amino acids are suggested to mitigate its toxicity by forming adducts. The emergence of acrylamide adducts may cause underestimation of acrylamide exposure level as well as trigger new safety problems. Based on the acrylamide elimination capability of four amino acids, this study chemically synthesized six amino acid-acrylamide adducts. Their structures were analyzed, followed by content determination in 10 commercially baking foods. The Michael adduct formed by one molecule of γ-aminobutyric acid (GABA) and acrylamide was most abundant in foods among six adducts. Furthermore, it markedly decreased the cytotoxicity of acrylamide in Caco-2 cells and GES-1 cells. This finding suggests that amino acids can be used to reduce acrylamide level in processed foods and mitigate its hazardous effects after intake.

The assessment of aflatoxin B1 (AFB1) exposure using isotope-dilution liquid chromatography-mass spectrometry (LCMS) of AFB1-lysine adducts in human serum albumin (HSA) has proven to be a highly productive strategy for the biomonitoring of AFB1 exposure. To compare samples across different individuals and settings, the conventional practice has involved the normalization of raw AFB1-lysine adduct concentrations (e.g., pg/mL serum or plasma) to the total circulating HSA concentration (e.g., pg/mg HSA). It is hypothesized that this practice corrects for technical error, between-person variance in HSA synthesis or AFB1 metabolism, and other factors. However, the validity of this hypothesis has been largely unexamined by empirical analysis. The objective of this work was to test the concept that HSA normalization of AFB1-lysine adduct concentrations effectively adjusts for biological and technical variance and improves AFB1 internal dose estimates. Using data from AFB1-lysine and HSA measurements in 763 subjects, in combination with regression and Monte Carlo simulation techniques, we found that HSA accounts for essentially none of the between-person variance in HSA-normalized (R2 = 0.04) or raw AFB1-lysine measurements (R2 = 0.0001), and that HSA normalization of AFB1-lysine levels with empirical HSA values does not reduce measurement error any better than does the use of simulated data (n = 20,000). These findings were robust across diverse populations (Guatemala, China, Chile), AFB1 exposures (105 range), HSA assays (dye-binding and immunoassay), and disease states (healthy, gallstones, and gallbladder cancer). HSA normalization results in arithmetic transformation with the addition of technical error from the measurement of HSA. Combined with the added analysis time, cost, and sample consumption, these results suggest that it may be prudent to abandon the practice of normalizing adducts to HSA concentration when measuring any HSA adducts—not only AFB1-lys adducts—when using LCMS in serum/plasma. [ABSTRACT FROM AUTHOR]

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5-(Hydroxymethyl)-2-furfural (HMF), an active furfural, widely exists in various food products and has potential safety risks. It can be eliminated by occurring aldol condensation with α-unsubstituted ketones in the presence of catalysts. However, the elimination process between HMF and ketones from food is rarely studied. In this study, the adduct formation between HMF and zingerone (ZGR) catalyzed by proline was investigated. It revealed that the adduct formation led to 99.75% of HMF being trapped under the optimized reaction condition. Moreover, the in vitro digestion stability of HMF-ZGR adduct (HMZ) and its cytotoxicity against Caco-2 cells were evaluated. The results indicated that more than 75% of HMZ was remained after a three-stage simulated digestion. Following 24 and 48 h of incubation, HMZ exhibited cytotoxicity against Caco-2 cells with IC50 values of 41.47 ± 5.33 and 25.39 ± 3.12 mM, respectively, versus 35.39 ± 4.03 and 19.17 ± 2.10 mM by HMF.

Cyclopropylamine borane C3H5NH2BH3 (C3AB), 2-ethyl-1-hexylamine borane CH3(CH2)3CH(C2H5)CH2NH2BH3 (C2C6AB) and didodecylamine borane (C12H25)2NHBH3 ((C12)2AB) are three new amine borane adducts (ABAs). They are synthesized by reaction of the corresponding amines with a borane complex, the reaction being exothermic as shown by Calvet calorimetry. The successful synthesis of each has been demonstrated by FTIR, Raman and NMR. For instance, the 11B NMR spectra show the presence of signals typical of the NBH3 environment, thereby implying the formation of B–N bonds. The occurrence of dihydrogen bonds (DHBs) for each of the ABAs has been highlighted by DSC and FTIR, and supported by DFT calculations (via the Mulliken charges for example). When heated, the three ABAs behave differently: C3AB and C2C6AB decompose from 68 to 100 °C whereas (C12)2AB is relatively stable up to 173 °C. That means that these ABAs are not appropriate as hydrogen carriers, but the ‘most’ stable (C12)2AB could open perspectives for the synthesis of advanced materials.

Here is a theoretical synthesis for a cinnamaldehyde adduct formation of a hypothetically proposed lysergamide derivative named cinnamylidene-bislysergamide or lysergic acid biscinnamylidene amide (LSBC). This lysergamide name and abbreviation is in keeping with names of other lysergamide derivatives, such as d-lysergic acid amine (LSA), lysergic acid 2-butyl amide (LSB), lysergic acid diethylamide (LSD), d-lysergic acid a-hydroxyethylamide (LSH), lysergic acid methylisopropylamide (LSMIP), and lysergic acid 3-pentyl amide (LSP). Lysergamides are generally psychedelic in nature. The evidence for LSBC adduct formation is plausible, but the evidence supporting its psychedelic effects is weak. [ABSTRACT FROM AUTHOR]

Chitosan is a cationic polymer capable of binding acidic drugs. In addition, it has haemostatic and antimicrobial activity. Chitosan derivatives withanti-fibrinolytic properties may present increased effectiveness, especially when the added substance forms an adduct with chitosan. The aim of this work was to study the haemostatic action of the chitosan-tranexamic acid complex. Two chitosan solutions (molecularweight of 250 and 625 kDa at pH 5.7 and 6.2, and after tranexamic acid had been added to chitosan solutions) werestudied. Haemostatic evaluation was performed on white outbred mice. The time to complete cessation of bleeding from the tail was determined. Chitosan 625 kDa at pH 6.2 had the best haemostatic properties. Adding tranexamic acid to the chitosan solution reduced the bleeding time. This phenomenon was more pronounced for chitosan 625 kDa. Compared with control animals, this chitosan reduced bleeding arrest time by 30% and the chitosan-tranexamic acid adduct reduced the bleeding arrest time by 75%. [ABSTRACT FROM AUTHOR]

The assessment of aflatoxin B1 (AFB1) exposure using isotope-dilution liquid chromatography-mass spectrometry (LCMS) of AFB1-lysine adducts in human serum albumin (HSA) has proven to be a highly productive strategy for the biomonitoring of AFB1 exposure. To compare samples across different individuals and settings, the conventional practice has involved the normalization of raw AFB1-lysine adduct concentrations (e.g., pg/mL serum or plasma) to the total circulating HSA concentration (e.g., pg/mg HSA). It is hypothesized that this practice corrects for technical error, between-person variance in HSA synthesis or AFB1 metabolism, and other factors. However, the validity of this hypothesis has been largely unexamined by empirical analysis. The objective of this work was to test the concept that HSA normalization of AFB1-lysine adduct concentrations effectively adjusts for biological and technical variance and improves AFB1 internal dose estimates. Using data from AFB1-lysine and HSA measurements in 763 subjects, in combination with regression and Monte Carlo simulation techniques, we found that HSA accounts for essentially none of the between-person variance in HSA-normalized (R2 = 0.04) or raw AFB1-lysine measurements (R2 = 0.0001), and that HSA normalization of AFB1-lysine levels with empirical HSA values does not reduce measurement error any better than does the use of simulated data (n = 20,000). These findings were robust across diverse populations (Guatemala, China, Chile), AFB1 exposures (105 range), HSA assays (dye-binding and immunoassay), and disease states (healthy, gallstones, and gallbladder cancer). HSA normalization results in arithmetic transformation with the addition of technical error from the measurement of HSA. Combined with the added analysis time, cost, and sample consumption, these results suggest that it may be prudent to abandon the practice of normalizing adducts to HSA concentration when measuring any HSA adducts—not only AFB1-lys adducts—when using LCMS in serum/plasma.

Dihydromyricetin (DMY) was employed to reduce the yield of furfural derived from the Amadori rearrangement product of l-threonine and d-xylose (Thr-ARP) by trapping Thr-ARP, 3-deoxyxyosone (3-DX), and furfural to form adducts. The effect of different concentrations of DMY at different pH values and temperatures on the reduction of furfural production was studied, and the results showed that DMY could significantly reduce furfural production at higher pH (pH 5-7) and lower temperature (110 °C). Through the surface electrostatic potential analysis by Gaussian, a significant enhancement of the C 6 nucleophilic ability at higher pH (pH ≥ 5) was observed on DMY with hydrogen-dissociated phenol hydroxyl. The nucleophilic ability of DMY led to its trapping of Thr-ARP, 3-DX, and furfural with the generation of the adducts DMY-Thr-ARP, DMY-3-DX, and DMY-furfural. The formation of the DMY-Thr-ARP adduct slowed the degradation of Thr-ARP, caused the decrease of the 3-DX yield, and thereby inhibited the conversion of 3-DX to furfural. Therefore, DMY-Thr-ARP was purified, and the structure was identified by nuclear magnetic resonance (NMR). The results confirmed that C 6 or C 8 of DMY and carbonyl carbon in Thr-ARP underwent a nucleophilic addition reaction to form the DMY-Thr-ARP adduct. In combination with the analysis results of Gaussian, most of the DMY-Thr-ARP adducts were calculated to be C 6 -DMY-Thr-ARP. Furthermore, the formation of DMY-furfural caused furfural consumption. The formation of the adducts also shunted the pathway of both Thr-ARP and 3-DX conversion to furfural, resulting in a decrease in the level of furfural production.