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1.
Food Chem ; 429: 136971, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37516052

RESUMO

There is a huge demand for brewing water in tea consumption, and the sensory flavor of tea infusion is significantly affected by the water used for brewing. To investigate the impact of brewing water on the aroma of tea infusions made from Camelia senensis, the three tea infusions of green, oolong and black tea brewed by six different drinking waters were analyzed by sensory evaluation, solid-phase microextraction, gas chromatography-mass spectrometry, and chemometrics. Brewing water with high pH values (>8.10) and high TDS content (>140 ppm) resulted in a lower overall aroma acceptability for tea infusion, where HCO3-, Ca2+ and Mg2+ were key influencing ions. A total of 86, 106, and 131 volatiles were identified in green, oolong and black tea infusions, respectively, which were strongly influenced by six different brands of waters. Decanal, dimethyl sulfide, ß-ionone and linalool were potent volatiles in tea aroma changes caused by brewing water.


Assuntos
Chá , Água/química , Chá/química , Cromatografia Gasosa-Espectrometria de Massas , Microextração em Fase Sólida , Íons/química , Compostos Orgânicos Voláteis/química , Odorantes
2.
ACS Chem Neurosci ; 14(15): 2618-2633, 2023 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-37487115

RESUMO

Uranium (U) is naturally present in ambient air, water, and soil, and depleted uranium (DU) is released into the environment via industrial and military activities. While the radiological damage from U is rather well understood, less is known about the chemical damage mechanisms, which dominate in DU. Heavy metal exposure is associated with numerous health conditions, including Alzheimer's disease (AD), the most prevalent age-related cause of dementia. The pathological hallmark of AD is the deposition of amyloid plaques, consisting mainly of amyloid-ß (Aß) peptides aggregated into amyloid fibrils in the brain. However, the toxic species in AD are likely oligomeric Aß aggregates. Exposure to heavy metals such as Cd, Hg, Mn, and Pb is known to increase Aß production, and these metals bind to Aß peptides and modulate their aggregation. The possible effects of U in AD pathology have been sparsely studied. Here, we use biophysical techniques to study in vitro interactions between Aß peptides and uranyl ions, UO22+, of DU. We show for the first time that uranyl ions bind to Aß peptides with affinities in the micromolar range, induce structural changes in Aß monomers and oligomers, and inhibit Aß fibrillization. This suggests a possible link between AD and U exposure, which could be further explored by cell, animal, and epidemiological studies. General toxic mechanisms of uranyl ions could be modulation of protein folding, misfolding, and aggregation.


Assuntos
Doença de Alzheimer , Urânio , Animais , Peptídeos beta-Amiloides/metabolismo , Doença de Alzheimer/metabolismo , Íons/química , Amiloide
3.
Int J Biol Macromol ; 235: 123871, 2023 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-36870628

RESUMO

The effects of MgCl2 and NaCl concentrations on potato starch were analysed. With an increase in MgCl2 and NaCl concentrations from 0 to 4 mol/L, the gelatinisation properties, crystalline properties, and sedimentation rate of potato starch all showed a trend of rising first and then falling (or falling first and then rising). The inflection points of the effect trends were observed at 0.5 mol/L. This inflection point phenomenon was further analysed. At higher salt concentrations, starch granules were found to absorb external ions. These ions enhance the hydration of starch molecules and promote starch gelatinisation. When NaCl and MgCl2 concentrations were increased from 0 to 4 mol/L, the starch hydration strength increased 52.09 and 65.41 times, respectively. At lower salt concentrations, the ions that naturally exist in starch granules seep out of the granules. The exudation of these ions may cause a certain degree of damage to the native structure of starch granules.


Assuntos
Cloreto de Sódio , Solanum tuberosum , Cloreto de Sódio/farmacologia , Solanum tuberosum/química , Amido/química , Fenômenos Químicos , Íons/química
4.
J Mol Recognit ; 36(6): e3013, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36999889

RESUMO

This paper presents the expansion of an optical, chemical sensor that can rapidly and reliably detect, quantify, and remove Ni(II) ions in oil products and electroplating wastewater sources. The sensor is based on mesoporous silica nanospheres (MSNs) that have an extraordinary surface area, uniform surface morphology, and capacious porosity, making them an excellent substrate for the anchoring of the chromoionophoic probe,3'-{(1E,1' E)-[(4-chloro-1,2 phenylene)bis (azaneylylidene)]-bis(methaneylylidene)}bis(2-hydroxybenzoic acid) (CPAMHP). The CPAMHP probe is highly selective and sensitive to Ni(II), enabling it to be used in naked-eye colorimetric recognition of Ni(II) ions. The MSNs provide several accessible exhibited sites for uniform anchoring of CPAMHP probe molecules, making it a viable chemical sensor even with the use of naked-eye sensing. The surface characters and structural analysis of the MSNs and CPAMHP sensor samples were examined using various techniques. The CPAMHP probe-anchored MSNs exhibit a clear and vivid color shift from pale yellow to green upon exposure to various concentrations of Ni(II) ions, with a reaction time down to approximately 1 minute. Furthermore, the MSNs can serve as a base to retrieve extremely trace amounts of Ni(II) ions, making the CPAMHP sensor a dual-functional device. The calculated limit of recognition for Ni(II) ions using the fabricated CPAMHP sensor samples is 0.318 ppb (5.43 × 10-9 M). The results suggest that the proposed sensor is a promising tool for the sensitive and reliable detection of Ni(II) ions in petroleum products and for removing Ni(II) ions in electroplating wastewater; the data indicate an excellent removal of Ni (II) up to 96.8%, highlighting the high accuracy and precision of our CPAMHP sensor.


Assuntos
Nanosferas , Petróleo , Dióxido de Silício/química , Galvanoplastia , Águas Residuárias , Nanosferas/química , Íons/química , Petróleo/análise
5.
Rapid Commun Mass Spectrom ; 37(8): e9481, 2023 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-36721310

RESUMO

RATIONALE: The chemical constituents of Chinese patent medicine are usually different from those of crude medicine because of specific preparation processes. Chimonanthus nitens Oliv. leaf granule is widely used for prevention against COVID-19 in China. However, no research has been reported on the chemical constituents of the granule and their variation during the preparation process. METHODS: Fragmentation patterns of reference compounds were investigated using electrospray ionization mass spectrometry, and the new gas-phase reaction was demonstrated by electronic and steric effects and calculated chemistry. Then, a strategy based on new fragmentation patterns was used to profile aromatic constituents. In addition, based on untargeted metabolomics analytical workflow, a comparison was made on the chemical constituents of the leaf and granule. RESULTS: New fragmentation patterns related to two competing reactions, ring-opening and ring-closing reactions for coumarin, have been proposed and investigated in depth. The newly established diagnostic ion at m/z 81.0331 worked strongly in the assignment of OH-7 and substituent at C-8 of coumarin. McLafferty rearrangement occurring in coumarin glycoside while sugar group locating at C-4 was first observed, and new diagnostic ions at m/z 147.0440, 119.0488, and 91.0543 were constructed. CONCLUSIONS: Aromatic constituents of the granule were first profiled. A total of 114 aromatic compounds were identified; of these 85 compounds were identified first. Kaempferol-7-O-neohesperidoside and its homologues were mostly enriched in the granule. Considering their reported bioactivities, these analogues possibly contribute greatly to clinical efficacy. Our results provided a new fragmentation theory for coumarins and a new material basis for the quality control of the granule.


Assuntos
COVID-19 , Medicamentos de Ervas Chinesas , Espectrometria de Massas por Ionização por Electrospray/métodos , Medicamentos de Ervas Chinesas/química , Íons/química , Folhas de Planta/química , Cromatografia Líquida de Alta Pressão/métodos
6.
Dalton Trans ; 52(8): 2197-2208, 2023 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-36734607

RESUMO

Metal ions play a very important role in nature and their homeostasis is crucial. A lot of metal-related chemical research activities are ongoing that concern metal-based drugs or tools, such as chelation therapy, metal- and metabolite sensors, metallo-drugs and prodrugs, PET and MRI imaging agents, etc. In most of these cases, the applied chelator/ligand (L) or metal-ligand complex (M-L) has at least to pass the blood plasma to reach the target. Hence it is exposed to several metal-binding proteins (mainly serum albumin and transferrin) and to all essential metal ions (zinc, copper, iron, etc.). This holds also for studies in cultured cells when fetal calf serum is used in the medium. There is a risk that the applied compound (L or M-L) in the serum is transformed into a different entity, due to trans-metallation and/or ligand exchange reactions. This depends on the thermodynamics and kinetics. For kinetically-labile complexes, the complex stability with all the ligands and all metal ions present in serum is decisive in evaluating the thermodynamic driving force towards a certain fate of the chelator or metal-ligand complex. To consider that, an integrative view is needed on the stability constants, by taking into account all the metal ions present and all the main proteins to which they are bound, as well as the non-occupied metal binding site in proteins. Only then, a realistic estimation of the complex stability, and hence its potential fate, can be done. This perspective aims to provide a simple approach to estimate the thermodynamic stability of labile metal-ligand complexes in a blood plasma/serum environment. It gives a guideline to obtain an estimation of the plasma and serum complex stability and metal selectivity starting from the chemical stability constants of metal-ligand complexes. Although of high importance, it does not focus on the more complex kinetic aspects of metal-transfer reactions. The perspective should help for a better design of such compounds, to perform test tube assays which are relevant to the conditions in the plasma/serum and to be aware of the importance of ternary complexes, kinetics and competition experiments.


Assuntos
Quelantes , Complexos de Coordenação , Quelantes/química , Soro , Ligantes , Polegar , Metais/metabolismo , Termodinâmica , Complexos de Coordenação/química , Transferrina/metabolismo , Plasma/metabolismo , Íons/química
7.
Carbohydr Polym ; 301(Pt A): 120294, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36436863

RESUMO

This work presents a novel polymer-based adsorbent, Sodium Dodecyl Sulphate modified alginate-pectin gel beads (APS221) prepared via controlled freeze drying & air drying, for the removal of copper ions from the aqueous solution. This work also critically discusses the role played by various components and their concentrations in the success of APS221. Addition of pectin to alginate resulted into approximately 150 % increase in the metal removal performance of the adsorbent while addition of SDS into alginate-pectin complex enhanced the performance by 14 % approximately, taking the maximum adsorption capacity of final complex APS221 to 111.11 mg/g. Our characterization studies revealed that the adsorption happened predominantly by complexation and ion-exchange mechanisms, and hence despite having a higher surface area, freeze-dried variant showed lesser adsorption capacity than air-dried variant as there was a loss of ion-exchange sites resulting from breakage of crosslinking bonds due to chain elongation. The adsorption process was found to follow Langmuir isotherm and pseudo-second order kinetics with a good fit of experimental data. Further, operating parameters have been optimized via RSM to, simultaneously, maximize the utilization of the adsorbent and minimize the cost of the process. Stability studies showed that APS221 beads could be used up to eight cycles.


Assuntos
Alginatos , Poluentes Químicos da Água , Alginatos/química , Cobre/química , Dodecilsulfato de Sódio , Pectinas , Poluentes Químicos da Água/química , Concentração de Íons de Hidrogênio , Íons/química
8.
J Am Soc Mass Spectrom ; 34(1): 36-47, 2023 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-36488200

RESUMO

Identification of lipopeptides (LpAA) synthesized from bacteria involves the study of structural characterization. Twenty LpAA have been characterized using commercial tandem high-resolution mass spectrometers in negative electrospray, employing nonresonant excitation in "RF only" collision cells and generally behave identically. However, [LpAA-H]- (AA = Asp or Glu) shows surprising fragmentation pathways, yielding a complementary fatty acid carboxylate and dehydrated amino acid fragment anions. In this study, the dissociation mechanisms of [C12Glu-H]- were determinate using energy-resolved mass spectrometry (ERMS). Product ion breakdown profiles are, generally, unimodal with full width at half-maximum (fwhm) increasing as product ion m/z ratios decrease, except for the two product ions of interest (fatty acid carboxylate and dehydrated glutamate) characterized by broad and composite profiles. Such behavior was already shown for other ions using a custom-built guided ion beam mass spectrometer. In this study, we investigate the meaning of these particular profiles from an ERMS breakdown, using fragmentation mechanisms depending on the collision energy. ERMS on line with ion mobility spectrometry (IMS), here called ER-IMS, provides a way to probe such questions. Broad or composite profiles imply that the corresponding product ions may be generated by two (or more) pathways, resulting in common or isomeric product ion structures. ER-IMS analysis indicates that the fatty acid carboxylate product ion is produced with a common structure through different pathways, while dehydrated glutamate has two isomeric forms depending on the mechanism involved. Drift time values correlate with the calculated collision cross section that confirms the product ion structures and fragmentation mechanisms.


Assuntos
Ácido Glutâmico , Espectrometria de Mobilidade Iônica , Íons/química , Espectrometria de Massas/métodos , Isomerismo , Espectrometria de Massas por Ionização por Electrospray/métodos
9.
Sci Total Environ ; 858(Pt 2): 159796, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36374730

RESUMO

In consideration of the severe hazards of radioactive uranium pollution, the rapid assessment of uranium in field and in vivo are urgently needed. In this work a novel biocompatible and sensitive visual fluorescent sensor based on aggregation-induced emission (AIE) was designed for onsite detection of UO22+ in complex environmental samples, including wastewater from Uranium Plant, river water and living cell. The AIE-active sensor (named as TPA-SP) was prepared with a "bottom-up" strategy by introducing a trianiline group (TPA) with a single-bond rotatable helix structure into the salicylaldehyde Schiff-base molecule. The photophysical properties, cytotoxicity test, recognition mechanism and the analytical performance for the detection of UO22+ in actual water samples and cell imaging were systematically investigated. TPA-SP exhibited high sensitivity and selectivity toward UO22+ as well as outstanding anti-interference ability against large equivalent of different ions in a wide effective pH range. A good linear relationship in the UO22+ concentration range of 0.05-1 µM was obtained with a low limit of detection (LOD) of 39.4 nM (9.38 ppb) for uranium detection. The prepared visual sensor showed great potential for fast risk assessment of uranium pollution in environmental systems. In addition, our results also indicated that the TPA-SP exhibited very low cytotoxicity in cells and demonstrated great potential for uranium detection in vivo.


Assuntos
Urânio , Urânio/análise , Água/química , Limite de Detecção , Íons/química , Bases de Schiff
10.
J Phys Chem B ; 126(44): 9105-9122, 2022 11 10.
Artigo em Inglês | MEDLINE | ID: mdl-36321420

RESUMO

A wide range of systems, both engineered and natural, feature aqueous electrolyte solutions at interfaces. In this study, the structure and dynamics of water at the two prevalent crystallographic terminations of gamma-alumina, [110] and [100], and the influence of salts─sodium chloride, ammonium acetate, barium acetate, and barium nitrate on such properties─were investigated using equilibrium molecular dynamics simulations. The resulting interfacial phenomena were quantified from simulation trajectories via atomic density profiles, angle probability distributions, residence times, 2-D density distributions within the hydration layers, and hydrogen bond density profiles. Analysis and interpretation of the results are supported by simulation snapshots. Taken together, our results show stronger interaction and closer association of water with the [110] surface, compared to [100], while ion-induced disruption of interfacial water structure was more prevalent at the [100] surface. For the latter, a stronger association of cations is observed, namely sodium and ammonium, and ion adsorption appears determined by their size. The differences in surface-water interactions between the two terminations are linked to their respective surface features and distributions of surface groups, with atomistic-scale roughness of the [110] surface promoting closer association of interfacial water. The results highlight the fundamental role of surface characteristics in determining surface-water interactions, and the resulting effects on ion-surface and ion-water interactions. Since the two terminations of gamma-alumina considered represent interfaces of significance to numerous industrial applications, the results provide insights relevant for catalyst preparation and adsorption-based water treatment, among other applications.


Assuntos
Óxido de Alumínio , Simulação de Dinâmica Molecular , Eletrólitos/química , Íons/química , Cloreto de Sódio/química
11.
J Am Soc Mass Spectrom ; 33(11): 2108-2119, 2022 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-36264209

RESUMO

An analytical approach based on reversed-phase liquid chromatography coupled to electrospray ionization Fourier-transform mass spectrometry in negative ion mode (RPLC-ESI-(-)-FTMS) was developed for the untargeted characterization of glucosinolates (GSL) in the polar extracts of four Brassica microgreen crops, namely, garden cress, rapeseed, kale, and broccoli raab. Specifically, the all ion fragmentation (AIF) operation mode enabled by a quadrupole-Orbitrap mass spectrometer, i.e., the systematic fragmentation of all ions generated in the electrospray source, followed by the acquisition of an FTMS spectrum, was exploited. First, the best qualifying product ions for GSL were recognized from higher-energy collisional dissociation (HCD)-FTMS2 spectra of representative standard GSL. Extracted ion chromatograms (EIC) were subsequently obtained for those ions from RPLC-ESI(-)-AIF-FTMS data referred to microgreen extracts, by plotting the intensity of their signals as a function of retention time. The alignment of peaks detected in the EIC traces was finally exploited for the recognition of peaks potentially related to GSL, with the EIC obtained for the sulfate radical anion [SO4]•- (exact m/z 95.9523) providing the highest selectivity. Each putative GSL was subsequently characterized by HCD-FTMS2 analyses and by collisionally induced dissociation (CID) multistage MSn (n = 2, 3) acquisitions based on a linear ion trap mass spectrometer. As a result, up to 27 different GSLs were identified in the four Brassica microgreens. The general method described in this work appears as a promising approach for the study of GSL, known and novel, in plant extracts.


Assuntos
Brassica , Glucosinolatos , Glucosinolatos/análise , Glucosinolatos/química , Cromatografia Líquida/métodos , Espectrometria de Massas por Ionização por Electrospray/métodos , Íons/química , Extratos Vegetais
12.
Se Pu ; 40(9): 782-787, 2022 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-36156624

RESUMO

Ion mobility-mass spectrometry (IM-MS) is a combination of ion mobility separation and mass spectrometry technologies. In IM-MS, analytes are ionized by the ion source to form gas-phase ions, which are then rapidly separated using ion mobility based on their mobility difference, under the influence of both neutral buffer gas and an electric field, and then traversed and detected using mass spectrometry, which can separate ions based on mass-to-charge ratio. Furthermore, IM-MS could provide not only mass-to-charge ratio parameters like MS1 and MS2 spectra but also new structural information for component identification like collision cross-section values, drift time, arrival time, compensation voltage, and so on, which can be employed to resolve complex chemical components, especially indistinguishable isomers using mass spectrometry alone. In recent years, with the development of IM-MS technologies, IM-MS has become more widely employed in chemical analysis in traditional Chinese medicines (TCMs). Firstly, IM-MS was been successfully used in the separation of complex TCMs complex extract from interfering isobaric species. Secondly, IM-MS also offers new types of MS/MS fragmentation modes, and the combination of IM separation and fragmentation modes enables the acquisition of more specific and detailed fragment ion spectra. Thirdly, the collision cross-section is introduced by IM-MS, which is a unique physicochemical property of a component. Related data post-processing strategies based on experimentally derived collision cross-section values have been continuously developed in recent years to make full use of the collision cross-section values, these data post-processing strategies include collision cross-section database matching, theoretical collision cross-section values matching, machine-learning-based collision cross-section values prediction matching, mass-to-charge ratio versus collision cross-section correlation trend lines and so on. In doing so, these diverse strategies can greatly enhance the reliability and accuracy of the structural annotation of TCM compounds. This review primarily briefly introduces the major types and basic principles of IM-MS. The applications of IM-MS in TCM chemical analysis are highlighted in this study. The current applications of IM-MS in improving TCM chemical component separation are summarized, followed by a discussion of several strategies for enhancing separation selectivity. This review also offers some new fragmentation modes, novel data acquisition approaches, and collision cross-section data post-processing strategies applied in TCM qualitative analysis. Finally, the prospect of IM-MS applied in TCM chemical analysis is also discussed. This review provides approaches and ideas for future IM-MS research on TCM's chemical analysis.


Assuntos
Misturas Complexas , Espectrometria de Massas em Tandem , China , Misturas Complexas/análise , Cromatografia Gasosa-Espectrometria de Massas , Íons/análise , Íons/química , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem/métodos
13.
J Chromatogr A ; 1674: 463145, 2022 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-35594798

RESUMO

A comprehensive chemical profiling of traditional Chinese medicine is the basic issue for further pharmacological research and quality assessment. To facilitate chemical identification and potential components discovery, the present study proposed an integrated identification strategy guided by a self-built component database constructed from literatures to carry out the global profiling of complex matrixes. Lanqin Oral Liquid was applied as example to validate the feasibility of this strategy. Based on LQL Component Database containing 710 compounds, modified MDF windows was established to extract the interested analogues, isoquinoline alkaloids, flavonoids and iridoid glycosides, according to their regular integral masses and mass defect. For compounds with characteristic substructures, such as quinic acids, crocins and some glycoside derivatives, the associated neutral losses and diagnostic fragment ions were collected to assist in profiling. Directly matching the m/z or formulas in database was proposed to components with limited regularity of accurate masses and substructures, like indole alkaloids, sesquiterpenes and some nucleosides. Eventually, 170 ions of 1038 precursor ions were identified or temporarily deduced, including 59 alkaloids, 36 flavonoids, 48 terpenoids, 24 organic acids and their derivatives, 2 oligosaccharides, and 1 lignans. Among them, 52 putative compounds were confirmed by chemical standards. The results indicated that the database-oriented identification strategy could locate potential components quickly and eliminate interfering ions, which have the potential for in-depth analysis of compounds.


Assuntos
Alcaloides , Medicamentos de Ervas Chinesas , Cromatografia Líquida de Alta Pressão/métodos , Medicamentos de Ervas Chinesas/química , Flavonoides/análise , Íons/química , Glicosídeos Iridoides/análise , Medicina Tradicional Chinesa , Espectrometria de Massas em Tandem/métodos
14.
J Colloid Interface Sci ; 617: 274-283, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35278865

RESUMO

Rechargeable aqueous Zn - MnOx batteries show great potential for grid - scale storage due to cost - effectiveness and high safety. However, most of MnOx cathodes suffer from irreversible phase transformation into spinel ZnMn2O4 with reduced electrochemical activity after repeated charge/discharge cycles, leading to severe capacity decay. Herein, we reveal a strategic design utilizing glucose as the mediating agent to prepare nanostructured MnO/Mn3O4 material, which can be then transformed into lattice - expanded ZnxMn2O4 nanoparticles by electrochemical activation. The expanded structure of ZnxMn2O4 allows better accommodation of Zn2+ and H+ ions and undergoes reversible lattice expansion/contraction during charge/discharge process. Therefore, the lattice - expanded ZnxMn2O4 retains 121 mAh g-1 after 2000 cycles at 1 A g-1, exhibiting stable cycle performance in comparison with the parent MnO2 (63 mAh g-1) and well - crystalline ZnMn2O4 (58 mAh g-1). Moreover, through the comparison of MnO/Mn3O4, Mn3O4/MnO2, and pure Mn3O4 samples, MnO is found to play an important role in forming lattice - expanded spinel structure during the activation process.


Assuntos
Compostos de Manganês , Óxidos , Óxido de Alumínio , Glucose , Íons/química , Óxido de Magnésio , Compostos de Manganês/química , Óxidos/química , Zinco
15.
Rapid Commun Mass Spectrom ; 36(9): e9269, 2022 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-35156244

RESUMO

RATIONALE: Norpimarane diterpenes possess plentiful bioactivities and are widely distributed in herbs, such as Flickingeria fimbriata. Rapid characterization of these natural products in complicated plant extracts is of great importance, and electrospray ionization tandem mass spectrometry is a powerful tool for chemical constituent profiling. However, limited researches on their fragmentation mechanisms seriously hinder identification via mass spectrometry. METHODS: Three norpimarane diterpenes isolated from F. fimbriata via multiple types of column chromatography served as reference compounds, and collision-induced dissociation experiments were performed on them with a series of variable collision energies. Plausible fragmentation pathways were proposed based on product ions. To further validate the fragmentation mechanisms, the proton affinity and product ion energy were simulated by density functional theory at the B3LYP/6-31+G(d, p) level. RESULTS: Three main cleavage reactions induced skeleton breakage and resulted in characteristic ions, methyl (CH3 -20) migration, hydrogen arrangement and Retro-Diels-Alder reaction, among which methyl migration was firstly proposed for pimarane diterpenes. A series of common diagnostic ions were identified, such as m/z 133.1012, 121.1012, 119.0805 and 107.0855. Additionally, the constructed fragmentation mechanisms were successfully applied for fragment ion rationalization of previously reported isopimarane diterpenes. CONCLUSIONS: Fragmentation mechanisms of norpimarane diterpenes have been uncovered. Carbocation located at the C ring tends to result in methyl (CH3 -20) migration which has been rarely reported before. This characteristic dissociation reaction allows multiple diagnostic ions to be rationalized and aids in rationalizing fragmentation patterns of other diterpenes. The uncovered mechanisms also shed light on rapid identification of norpimarane diterpenes.


Assuntos
Diterpenos , Espectrometria de Massas em Tandem , Química Computacional , Íons/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Espectrometria de Massas em Tandem/métodos
16.
Molecules ; 26(22)2021 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-34834009

RESUMO

The aim of this study was to propose a complete approach for macroalgae biomass valorization into products useful for sustainable agriculture and environmental protection. In the first stage, the effects of macroalgal extracts and ZnO NPs (zinc oxide nanoparticles) on the germination and growth of radish were examined. Macroalgal extract was produced from freshwater macroalga, i.e., Cladophora glomerata by ultrasound assisted extraction (UAE). The extract was used to biosynthesize zinc oxide nanoparticles. In germination tests, extracts and solutions of ZnO NPs were applied on paper substrate before sowing. In the second stage, sorption properties of macroalga, post-extraction residue, and ZnO NPs to absorb Cr(III) ions were examined. In the germination tests, the highest values of hypocotyl length (the edible part of radish), i.e., 3.3 and 2.6 cm were obtained for 60 and 80% extract (among the tested concentrations 20, 40, 60, 80, and 100%) and 10 and 50 mg/L NPs, respectively. The highest sorption capacity of Cr(III) ions (344.8 mg/g) was obtained by both macroalga and post-extraction residue at a pH of 5 and initial Cr(III) ions concentration of 200 mg/L. This study proves that macroalgae and products based on them can be applied in both sustainable agriculture and wastewater treatment.


Assuntos
Biomassa , Clorófitas/química , Cromo , Hipocótilo/crescimento & desenvolvimento , Nanopartículas/química , Extratos Vegetais/química , Raphanus/crescimento & desenvolvimento , Alga Marinha/química , Óxido de Zinco , Cromo/química , Cromo/metabolismo , Íons/química , Íons/metabolismo , Óxido de Zinco/química , Óxido de Zinco/farmacologia
17.
Chem Biol Interact ; 349: 109661, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34537181

RESUMO

Phytochemical analysis of EtOH extract from leaves of Nectandra oppositifolia afforded three flavonoids: kaempferol (1), kaempferol-3-O-α-rhamnopyranoside (2) and kaempferol-3-O-α-(3,4-di-E-p-coumaroyl)-rhamnopyranoside (3), which were characterized by NMR and ESI-HRMS. When tested against the protozoan parasite Trypanosoma cruzi, the etiologic agent of Chagas disease, flavonoids 1 and 3 were effective to kill the trypomastigotes with IC50 values of 32.0 and 6.7 µM, respectively, while flavonoid 2 was inactive. Isolated flavonoids 1-3 were also tested in mammalian fibroblasts and showed CC50 values of 24.8, 48.7 and 153.1 µM, respectively. Chemically, these results suggested that the free aglycone plays an important role in the bioactivity while the presence of p-coumaroyl unities linked in the rhamnoside unity is important to enhance the antitrypanosomal activity and reduce the mammalian cytotoxicity. The mechanism of cellular death was investigated for the most potent flavonoid 3 in the trypomastigotes using fluorescent and luminescent-based assays. It indicated that this compound induced neither permeabilization of the plasma membrane nor depolarization of the membrane electric potential. However, early time incubation (20 min) with flavonoid 3 resulted in a constant elevation of the Ca2+ levels inside the parasite. This effect was followed by a mitochondrial imbalance, leading to a hyperpolarization and depolarization of the mitochondrial membrane potential, with reduction of the ATP levels. During this time, the levels of reactive oxygen species levels (ROS) were unaltered. The leakage of Ca2+ from the intracellular pools can affect the bioenergetics system of T. cruzi, leading to the parasite death. Therefore, flavonoid 3 can be a useful tool for future studies against T. cruzi parasites.


Assuntos
Cálcio/metabolismo , Flavonoides/química , Quempferóis/química , Lauraceae/química , Trypanosoma cruzi/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Permeabilidade da Membrana Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Feminino , Flavonoides/isolamento & purificação , Flavonoides/farmacologia , Íons/química , Lauraceae/metabolismo , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Extratos Vegetais/química , Folhas de Planta/química , Folhas de Planta/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Trypanosoma cruzi/efeitos dos fármacos
18.
Molecules ; 26(17)2021 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-34500638

RESUMO

The effect of humidity on sheep wool during irradiation by an accelerated electron beam was examined. Each of the samples with 10%, 53%, and 97% relative humidity (RH) absorbed a dose of 0, 109, and 257 kGy, respectively. After being freely kept in common laboratory conditions, the samples were subjected to batch Co(II) sorption experiments monitored with VIS spectrometry for different lapses from electron beam exposure. Along with the sorption, FTIR spectral analysis of the wool samples was conducted for cysteic acid and cystine monoxide, and later, the examination was completed, with pH measuring 0.05 molar KCl extract from the wool samples. Besides a relationship to the absorbed dose and lapse, the sorptivity results showed considerable dependence on wool humidity under exposure. When humidity was deficient (10% RH), the sorptivity was lower due to limited transformation of cystine monoxide to cysteic acid. The wool pre-conditioned at 53% RH, which is the humidity close to common environmental conditions, demonstrated the best Co(II) sorptivity in any case. This finding enables the elimination of pre-exposure wool conditioning in practice. Under excessive humidity of 97% RH and enough high dose of 257 kGy, radiolysis of water occurred, deteriorating the sorptivity. Each wool humidity, dose, and lapse showed a particular scenario. The time and humidity variations in the sorptivity for the non-irradiated sample were a little surprising; despite the absence of electron irradiation, relevant results indicated a strong sensitivity to pre-condition humidity and lapse from the start of the monitoring.


Assuntos
Cobalto/química , Íons/química , Ovinos/metabolismo , Lã/química , Adsorção/fisiologia , Animais , Cistina/química , Elétrons , Umidade , Água/química
19.
PLoS One ; 16(8): e0255787, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34388208

RESUMO

Phytate is a dominant form of organic phosphorus (P) in the environment. Complexation and precipitation with polyvalent metal ions can stabilize phytate, thereby significantly hinder the hydrolysis by enzymes. Here, we studied the stability and hydrolyzability of environmentally relevant metal phytate complexes (Na, Ca, Mg, Cu, Zn, Al, Fe, Al/Fe, Mn, and Cd) under different pHs, presence of metal chelators, and thermal conditions. Our results show that the order of solubility of metal phytate complexes is as follows: i) for metal species: Na, Ca, Mg > Cu, Zn, Mn, Cd > Al, Fe, ii) under different pHs: pH 5.0 > pH 7.5), and iii) in the presence of chelators: EDTA> citric acid. Phytate-metal complexes are mostly resistant towards acid hydrolysis (except Al-phytate), and dry complexes are generally stable at high pressure and temperature under autoclave conditions (except Ca phytate). Inhibition of metal complex towards enzymatic hydrolysis by Aspergillus niger phytase was variable but found to be highest in Fe phytate complex. Strong chelating agents such as EDTA are insufficient for releasing metals from the complexes unless the reduction of metals (such as Fe) occurs first. The insights gained from this research are expected to contribute to the current understanding of the fate of phytate in the presence of various metals that are commonly present in agricultural soils.


Assuntos
Complexos de Coordenação/química , Metais/química , Ácido Fítico/química , Alumínio/química , Cádmio/química , Cobre/química , Íons/química , Ferro/química , Magnésio/química , Manganês/química , Fósforo/química , Potássio/química , Sódio/química , Zinco/química
20.
Anal Biochem ; 627: 114263, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34052198

RESUMO

In this work, the bio sorption of mercury ion by garlic bio-adsorbent was studied. A batch and a continuous up-flow fixed-bed column system were used in this report. Differential pulse voltammetry was used to detecting the amount of mercury ion. Using Differential pulse voltammetry prevents the production of carcinogenic mercury vapor. In the batch system, various doses of bio-adsorbent were investigated. After that, the experimental data was fitted using Langmuir and Freundlich models. The experimental data were also fitted to the Thomas, Bohart-Adams, and Yan models for the continuous mode in a fixed bed of garlic bio-adsorbent. The maximum adsorption capacity estimated by the Thomas models was 23.5 mg g-1 and τ was 135.3 min. This adsorbent is also suitable for absorbing mercury from a real-life well water sample. It is renewable and can be used to absorb mercury several times.


Assuntos
Alho/química , Mercúrio/química , Águas Residuárias/química , Adsorção , Técnicas Eletroquímicas/métodos , Humanos , Íons/química , Cinética , Modelos Teóricos , Poluentes Químicos da Água/química , Purificação da Água/métodos
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