Electron Spray Ionization Mass Spectrometry Research Articles

Diaporchalasins A-E, New Cytochalasins from the Endophytic Fungus Diaporthe sp. BMX12 Isolated from Aquilaria sinensis.

Five new cytochalasins, diaporchalasins A-E (1-5), together with 14 known congeners (6-19) were isolated from the endophytic fungus Diaporthe sp. BMX12, which was isolated from the branches of Aquilaria sinensis. The structures of the new compounds were elucidated by extensive spectroscopic analyses including high-resolution electron spray ionization mass spectrometry (HR-ESI-MS) and nuclear magnetic resonance (NMR). Their absolute configurations were assigned by theoretical electronic circular dichroism (ECD) calculations. Compounds 11 and 12 featuring a keto carbonyl at C-21 displayed cytotoxicity toward K562, BEL-7402, SGC-7901, A549, and HeLa cell lines with IC50 values ranging from 4.4 to 47.4 μM.

New isoindolinone derivatives isolated from the fruiting bodies of the basidiomycete Hericium coralloides

Preparative high-performance liquid chromatography (HPLC) purification of the ethyl acetate extract derived from dried basidiomes of the European mushroom Hericium coralloides led to the identification of two previously undescribed isoindolinone derivatives named corallocins D and E (1-2). The structures of the compounds were elucidated based on HR-ESI-MS (high-resolution electron spray ionization mass spectrometry), interpretation of 1D and 2D NMR spectra, electronic circular dichroism (ECD) experiments, and comparisons with published and theoretical data. The metabolites were tested for their cytotoxic and antimicrobial effects in vitro where weak to moderate biological effects were observed against HeLa cells (KB 3.1), Mucor hiemalis and Bacillus subtilis.

Violet dyes of the 1860s: Hofmann, Britannia, violet de Paris, Wanklyn’s, and Crystal violet (1883)

Two 19th-century historical violet dyes from the Historische Farbstoffsammlung, Technical University of Dresden, have been analysed by liquid chromatography–mass spectrometry (LC-MS). The data are presented as charts with retention time and two scales: electron spray mass spectrometry counts ( m/z) and milli-absorption units (UV). These dyes are complex mixtures as anticipated from the synthetic methods involving partial alkylation of rosaniline or synthesis using mixtures of N-methylaniline and N,N-dimethylaniline. The charts typically show chromophores separated by CH2 units which have separated well. Hofmann’s violet is presumably made by Hofmann’s method of synthesis, but the analyses do not verify with certainty who the inventors are because of the complexity of the dye mixtures.

Synthesis of efficient light harvesting Cr, N Co-doped TiO2 nanoparticles for enhanced visible light photocatalytic degradation of xanthene dyes; eosin yellow and rose bengal.

To solve the problem of water pollution, using environment friendly and cost effective method in short time is the need of hour. In this work, chromium (Cr) and nitrogen (N) co-doped TiO2 nanoparticles were synthesized and were used for the photocatalytic degradation of dyes under visible light. The synergistic effect of metal and non-metal co-dopants added would result in appropriate reduction of band gap {from 3.2 eVof TiO2 to 2.67eV}, decrease in recombination rate of charge carriers by trapping electrons and holes, and in better light harvesting capacity. Nanoparticles were synthesized by sol-gel method and characterized using ultraviolet-visible (UV-VIS) spectroscopy, fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM), zeta potential, X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET)analysis, field emission scanning electron microscopy (FE-SEM), and RAMAN spectroscopy. Eosin yellow (EY) and rose bengal (RB) were subjected to photocatalytic degradation under solar light to check the photocatalytic activity of the synthesized nanoparticles. Effects of dye concentration, the concentration of nanoparticles, time, and pH were investigated to optimize the parameters. The results obtained were remarkable for 20ppm EY solution took 10min using 1 gL-1 NPs at pH 3 and 10ppm RB solution took 5min using 0.75 gL-1 NPs at pH 5.78 (original pH) for complete degradation. Kinetics studies were also performed and both dyes followed pseudo-second-order kinetics with R2 values 0.99312 and 0.99712 for EY and RB, respectively. The study of degraded products was conducted using high-performance liquid chromatography (HPLC) hyphenated with electron spray ionization mass spectroscopy (ESI-MS) (LC-MS) and possible degradation pathways were made for both dyes. A reusability test was also performed showing the efficiency of the particles was up to 88% after 3 cycles of use. These notable results can be attributed to the efficient removal of organic pollutants using the proposed dopants in this study.

Thiourea-based low molecular-mass organogelators from (+)-dehydroabietylamine

Three new thiourea-based thermo-reversible, low molecular weight organogelators (LMOGs) 3-5 have been synthesized using (+)-Dehydroabietylamine (DAA, a tricyclic diterpene) employing DLS (Diterpene-Linker-spacer) strategy. (+) DAA was converted into isothiocynates through a cascade of reactions and cross-coupled with primary amines to furnish thiourea 3-5 with respective spacers. The structures of gelators 3-5 were confirmed through 1H-NMR and 13C-NMR spectroscopy, high-resolution electron spray ionization mass spectrometry (HRESI–MS, positive mode) and FTIR spectroscopy. Gelation potential of gelators 3-5 was investigated through inverted test tube method and sol–gel transition measured by ball-dropping method. The results revealed that unbranched alkyl groups furnish gelation and their gelation ability increases with increasing spacer length. Gelator 5 with dodecyl chain found to be excellent gelator that can gelate hexane (spontaneously), toluene, methanol, ethanol, petrol, and diesel. Morphology of gels was studied though scanning electron microscopy exhibiting fibrillar to lamellar structure with a thickness in the range of 9.5 nm to 5.0 μm with increasing length of spacer.

Phytochemical characterization, antioxidant activity and antihypertensive evaluation of Ocimum basilicum L. in l-NAME induced hypertensive rats and its correlation analysis

Ocimum basilicum Linn. (basil) is an aromatic culinary herb that has shown a great potential in therapeutic world. It has many promising pharmacological activities that make it centre for investigations for many researchers. Current study has been planned to determine chemical constituents of basil leaves extracts and their in-vitro and ex-vivo antioxidant and in-vivo antihypertensive potential. GC-MS studies of non-polar extracts showed presence of 75 compounds including monoterpenes, hydrocarbons, sesquiterpenes, triterpenes, phyto-sterols and phthalates. Higher percentages of fatty acids were also identified. The major compounds include linalool (7.65%), terpineol (1.42%), tau-cadinol (13.55%), methyl palmitate (14.24%), palmitic acid (14.31%), linolenic acid (1.30%) and methyl linolenate (17.72%). Electron spray ionization mass spectrometry ESI-HRMS/MS of the polar extracts revealed the presence of alkaloids, phenolic acid, amino acid, coumarin, lignin, flavanoid and terpene derivative. Total phenolic content and total flavonoid content were determined using spectrophotometric technique and calculated as gallic acid equivalents GAE/g dry weight and rutin equivalent RE/g of dry weight respectively. The highest phenolic content and flavonoid content were found in ethyl acetate extract 9.40 mg GAE/g and 15.9 mg RE/g of dry weight. All the extracts showed significant antioxidant activity in DPPH and ABTS cation decolorization assays. Dichloromethane extract possess the highest DPPH scavenging activity, i.e., 64.12% ± 0.23 at concentration of 4 mg/ml. Moreover in ex-vivo studies all the extracts showed prominent effect by inhibiting AAPS induce oxidation in Human erythrocytes being 69.24% ± 0.18 in dichloromethane extract, 64.44% ± 0.04 in ethyl acetate and 53.33% ± 0.09 in acetone extract. The methanol extract of O. basilicum exhibited significant decrease in systolic blood pressure in l-Name induced hypertensive rats at the dose of 50 mg/kg for 28 days. Total phenolic content had a higher linear correlation (r = 0.678) with antihypertensive activity, with a level of significance 95% showing that phenolic compounds in the leaves of the plant has important role in inhibiting l –NAME induced hypertension while flavonoid compounds may play a key role in the antioxidant activities of the plant, through synergism. Conclusively, O. basilicum leaves with bioactive metabolites are a potential source for the development of antihypertensive drugs.

Study of In Silico on Schiff Base Ligand Against Mycobacterium Tuberculosis

Here, we have synthesized the hetero-atoms containing; 3, 4, 6–Triazabicyclo [6, 3, 1] dodeca–1 (12), 2, 6, 8, 10–pentene–5–thione (TBD) macrocyclic Schiff base ligand for the application in antituberculosis (anti-TB). This TBD ligand moiety has high donor ability due to the presence of three nitrogen donor atoms, which are also the reason for the interaction between the ligand and protein molecule. The TBD Schiff base ligand is characterized by various spectroscopic techniques such as; Fourier-Transform Infrared (FT-IR), Proton Nuclear Magnetic Resonance (1HNMR), and Ultraviolet-Visible (UV-Vis) and Electron Spray Ionization (ESI) Mass spectroscopy, to understand the bond stretching, the electronic environment of protons, electronic transitions (p–p* and <em>n</em>–p*), and M/Z values, respectively. The computational study was carried out to calculate the molecular docking score using AutoDock Vina software against the glutamine protein enzyme (PDB ID-3ZXR). The molecular docking score was –6.3 kcal mol<sup>-1</sup> for the TBD Schiff base ligand, whereas –4.6 kcal mol<sup>-1</sup> is reported for the standard drug (Pyrazinamide). The product formation yield of TBD Schiff base ligand is found to be ~78 % during synthesis.

Bioactive flavonoid from the Commelina obliqua Vahl. and its In vitro anti-inflammatory activity

<em>Commelina obliqua</em> Vahl. This plant is a member of the Commelinaceae family, commonly referred to as the dayflower family. An entirely new bioactive compound recently discovered and identified 3, 5, 7, 3' 4′-pentahydroxy flavone-7-O-L-ribopyranosyl-3′-O-D-galactopyranoside having a melting point 320-22<sup>°</sup>C, molecular formula C<sub>26</sub>H<sub>28</sub>O<sub>16</sub>, m/z [595-H]<sup>-</sup> ESI-MS negative mode by different chemical color reactions, chemical decomposition, and spectral analysis 1HNMR, 13CNMR, Electron spray ionization mass spectrometry, Fourier transform infrared spectroscopy. An<em> in vitro </em>anti-inflammatory test revealed significant anti-inflammatory effects besides the degradation of egg albumin. Compound M illustrated the more percentage inhibitory action (123.1974%) of protein denaturation at 500 μg/ml, and Diclofenac sodium demonstrated less inhibitory activity (120.0627%) at the equivalent combination. As a result, Compound M inhibits protein denaturation more effectively than Diclofenac sodium at the same combination. Therefore, compound M may utilize as an anti-inflammatory source.

Chiral Co3Y Propeller-Shaped Chemosensory Platforms Based on 19F-NMR

Two propeller-shaped chiral CoIII3YIII complexes built from fluorinated ligands are synthesized and characterized by single-crystal X-ray diffraction (SXRD), IR, UV-vis, circular dichroism (CD), elemental analysis, thermogravimetric analysis (TGA), electron spray ionization mass spectroscopy (ESI-MS), and NMR (1H, 13C, and 19F). This work explores the sensing and discrimination abilities of these complexes, thus providing an innovative sensing method using a 19F NMR chemosensory system and opening new directions in 3d/4f chemistry. Control experiments and theoretical studies shed light on the sensing mechanism, while the scope and limitations of this method are discussed and presented.

Bioactive phlorotannin as autophagy modulator in cervical cancer cells and advanced glycation end products inhibitor in glucotoxic C. elegans

Brown algae produce varieties of potent metabolites in order to adapt to extreme environment. Among these metabolites, polyphenols comprised of phlorotannins serve as powerful multifaceted bioactive with vast pharmacological potentials against non-communicable diseases like cancer and diabetes. In this study, a new phlorotannin was extracted from Padina tetrastromatica and characterized by Fourier Transform-Infrared, Nuclear Magnetic Resonance & Electronspray Ionization-Mass Spectroscopy. The phlorotannin exhibited potent DPPH and nitric oxide radical-scavenging activity in in-vitro, which were better than the standard antioxidants and other phlorotannins, previously reported. Further, the novel phlorotannin explicitly inhibited advanced glycation end-products formation in both in-vitro and in-vivo studies using hyperglycaemic C. elegans as an animal model and confirmed by live-cell fluorescence imaging. In addition, a significant modulation in expression of stress-responsive genes daf-2 and daf-16 were observed in phlorotannin treated hyperglycemic C. elegans. Moreover, the cytotoxic potential of phlorotannin (2,4,6-trioxa-1,3,5(1,3) tribenzenacyclohexaphane-15,35,55-triol) was explored for the first time in human cervical cancer cells (HeLa) and interesting observation was made that the cancer cell death was induced by activation of autophagy and pro-apoptotic protein markers i.e., LC3I/II, p21 and p53 that were confirmed by western-blot technique. Therefore, phlorotannin can be postulated as a potential bioactive for oxidative stress-mediated diseases, including diabetes and cancer.

3-Methoxy-5-methyl-12-phenylbenzacridinium Iodide

N-alkylacridinium derivatives are some of the most popular azo dye templates. Herein, we report the synthesis of 3-methoxy-5-methyl-12-phenylbenzacridinium iodide (MMPBAI) via N-alkylation. The structure of MMPBAI was elucidated using 1H Nuclear magnetic resonance (NMR), 13C NMR, Electronspray ionization mass spectrometry (ESI-MS), and Fourier-transform infrared spectroscopy (FT-IR). MMPBAI could not visualize double-stranded DNA in agarose gel, although the structural core would still be interesting as a template for new azo dyes.

A unique ternary Ce(III)-quercetin-phenanthroline assembly with antioxidant and anti-inflammatory properties

Quercetin is one of the most bioactive and common dietary flavonoids, with a significant repertoire of biological and pharmacological properties. The biological activity of quercetin, however, is influenced by its limited solubility and bioavailability. Driven by the need to enhance quercetin bioavailability and bioactivity through metal ion complexation, synthetic efforts led to a unique ternary Ce(III)-quercetin-(1,10-phenanthroline) (1) compound. Physicochemical characterization (elemental analysis, FT-IR, Thermogravimetric analysis (TGA), UV–Visible, NMR, Electron Spray Ionization-Mass Spectrometry (ESI-MS), Fluorescence, X-rays) revealed its solid-state and solution properties, with significant information emanating from the coordination sphere composition of Ce(III). The experimental data justified further entry of 1 in biological studies involving toxicity, (Reactive Oxygen Species, ROS)-suppressing potential, cell metabolism inhibition in Saccharomyces cerevisiae (S. cerevisiae) cultures, and plasmid DNA degradation. DFT calculations revealed its electronic structure profile, with in silico studies showing binding to DNA, DNA gyrase, and glutathione S-transferase, thus providing useful complementary insight into the elucidation of the mechanism of action of 1 at the molecular level and interpretation of its bio-activity. The collective work projects the importance of physicochemically supported bio-activity profile of well-defined Ce(III)-flavonoid compounds, thereby justifying focused pursuit of new hybrid metal-organic materials, effectively enhancing the role of naturally-occurring flavonoids in physiology and disease.

Novel trans iodo(2-(N-alkylsulfamoyl)phenyl)bis(-triphenylphosphine palladium) complexes: Synthesis, mass spectrometry, X-ray structural description, steric map, near infrared analyses and catalytic activities evaluation

2-iodo-N-ethylbenzenesulfonamide and 2-iodo-N-isopropylbenzenesulfonamide are used to prepare two novel palladium(II) complexes (4 and 5) by oxidative addition starting from Pd(PPh3)4. The desired complexes are fully characterized by 1H, 13C, 31P NMR and near infrared spectroscopy. Electron spray ionization mass spectrometry analyses showed identical fragmentation process of the complexes starting by the iodine cleavage. The molecular structures of the complexes 4 and 5 are confirmed by X-ray diffraction analysis. The crystal packing of these complexes are stabilized by the presence of hydrogen bonds established between oxygen and hydrogen atoms of the sulfonamide groups. In addition, Hirshfeld surface mapped over dnorm, Shape index and molecular electrostatic potential were used to describe the short interactions and electron reach domains. The analyses of molecular fingerprints reveal similar percentage of H···H (∼67%), H···C/C···H (∼23%), H···I/I···H (∼5%) and H···O/O···H (∼4.5%) contacts in 4 and 5. The valuation of the percentage of buried volume (%VBur) of these ligands shows that the N-ethyl- and N-isopropylbenzenesulfonamide substituents took around 30% share of the palladium coordination sphere. Finally, the catalytic activities of these new palladium complexes are evaluated in cyclopropanation of styrene and in atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA). The results showed that trans cyclopropane was obtained as major product independently to the tested catalyst. In polymerization reaction, the catalysts show moderate activity and did not induce a controlled polymerization of MMA.

A screening method for binding synthetic metallo-complexes to haem proteins

The introduction of a second coordination sphere, in the form of a protein scaffold, to synthetic catalysts can be beneficial for their reactivity and substrate selectivity. Here we present semi-native polyacrylamide gel electrophoresis (semi-native PAGE) as a rapid screening method for studying metal complex-protein interactions. Such a screening is generally performed using electron spray ionization mass spectrometry (ESI-MS) and/or UV–Vis spectroscopy. Semi-native PAGE analysis has the advantage that it does not rely on spectral changes of the metal complex upon protein interaction and can be applied for high-throughput screening and optimization of complex binding. In semi-native PAGE non-denatured protein samples are loaded on a gel containing sodium dodecyl sulphate (SDS), leading to separation based on differences in structural stability. Semi-native PAGE gel runs of catalyst-protein mixtures were compared to gel runs obtained with native and denaturing PAGE. ESI-MS was additionally realised to confirm protein-complex binding. The general applicability of semi-native PAGE was investigated by screening the binding of various cobalt- and ruthenium-based compounds to three types of haem proteins.

Multi-component self-assembled heteroleptic Cu(I) complex with defective coordination site as a fluorescent probe to detect Zn2+

Heteroleptic copper(I)–phosphine complexes have attracted considerable attention due to their diverse structures and photophysical properties. In this work, a novel heteroleptic binuclear copper (I) complex C1·2BF4ˉ was designed and synthesized by using hexaazatriphenylene (L1) and 4, 5-Bis(diphenylphosphino)-9, 9-dimethylxanthene (dppd) as functional ligands. Such dinuclear structure with defective site was fully characterized by NMR, single-crystal X-ray diffraction analysis, and electron spray ionization mass spectrometry (ESI-MS). UV-vis and fluorescence spectrum revealed that the well-defined Cu(I) complex had a green emission at 518 nm in acetonitrile solution, and a red emission at 824 nm in the solid state. The DFT calculation demonstrated that the energy gap between LUMO and HOMO orbitals reached 1.20 eV. Furthermore, such heteroleptic Cu(I) complex showed high sensitivity and selectivity towards Zn2+ in acetonitrile solution in “turn-on” mode, which can be attributed to the coordination interaction between Zn2+ and defective binding site of probe C1·2BF4−. The LOD for Zn2+ was calculated to be 0.298 µM, and the reversible “on-off” fluorescence sensing behavior can be recovered by alternative treatment with EDTA tetrasodium and Zn2+ salts in solution. The Cu(I) complex probe C1·2BF4ˉ had reversible redox property with weak electrochemical responses towards Zn2+ ions.

Sera Protein Signatures of Endometrial Cancer Lymph Node Metastases.

The presence of lymph node metastases in endometrial cancer patients is a critical factor guiding treatment decisions; however, surgical and imaging methods for their detection are limited by morbidity and inaccuracy. To determine if sera can predict the presence of positive lymph nodes, sera collected from endometrial cancer patients with or without lymph node metastases, and benign gynecology surgical patients (N = 20 per group) were subjected to electron spray ionization mass spectrometry (ES-MS). Peaks that were significantly different among the groups were evaluated by leave one out cross validation (LOOCV) for their ability to differentiation between the groups. Proteins in the peaks were identified by MS/MS of five specimens in each group. Ingenuity Pathway Analysis was used to predict pathways regulated by the protein profiles. LOOCV of sera protein discriminated between each of the group comparisons and predicted positive lymph nodes. Pathways implicated in metastases included loss of PTEN activation and PI3K, AKT and PKA activation, leading to calcium signaling, oxidative phosphorylation and estrogen receptor-induced transcription, leading to platelet activation, epithelial-to-mesenchymal transition and senescence. Upstream activators implicated in these events included neurostimulation and inflammation, activation of G-Protein-Coupled Receptor Gβγ, loss of HER-2 activation and upregulation of the insulin receptor.

Synthesis of α-Hydroxy Acids via Dehydrogenative Cross-Coupling of a Sustainable C2 Chemical (Ethylene Glycol) with Alcohols.

Ir(NHC) (NHC, N-heterocyclic carbene)-catalyzed dehydrogenative coupling of sustainable ethylene glycol and various bioalcohols can produce industrially valuable α-hydroxy acids (AHAs). This study is the first to report the sustainable synthesis of higher Cn AHAs, in addition to glycolic acid (C2 AHA) and lactic acid (C3 AHA). This catalytic system can be recycled to the seventh cycle while maintaining good yields. A reaction mechanism, including facile dehydrogenation of each alcohol and fast cross-coupling of dehydrogenated aldehydes forming products, was proposed based on 18O- and 2H-labeling experiments and electron spray ionization-mass spectrometry (ESI-MS) and NMR spectral analyses.

Solvents and Ligands Matter: Structurally Variable Palladium and Nickel Clusters Assembled by Tridentate Selenium- and Tellurium-Containing Schiff Bases

Structurally variable organochalcogen clusters containing palladium(II) and nickel(II) ions were assembled starting from the salicylidene-substituted dichalcogenides (Y-C6H4-N═CH-C6H4-OH)2 ({HLY}2, where Y = Se or Te), and palladium or nickel acetate. The tetrameric palladium clusters contain reduced chalcogenolato ligands {Y-C6H4-N═CH-C6H4-O)}2- ({L'Y}2-, where Y = Se or Te), while the initially formed trimeric nickel clusters contain the intact, coordinated dichalcogenides. The palladium clusters have a general formula of [Pd4(L'Y)4] and represent the first examples of palladium complexes where both a gyrobifastigial and a pseudocubane arrangement of the central Pd4Y4 unit could be established with the same ligand, only depending on the solvents used for crystallization. Reduced density gradient (RDG) considerations based on density functional theory calculations suggest that the commonly referred to stabilizing chalcogen-palladium or palladium-palladium interactions for the two geometric arrangements are weak van der Waals contacts resulting from the contact of two nonbinding lone pairs. In the case of the pseudocubane arrangement, a repulsive steric effect, which is indicated by RDG analysis, is clearly supported by the cuplike distortions detected in the solid-state structure of the compound. In contrast to the reactions with palladium acetate, where the dichalcogenides were cleaved, during similar reactions with nickel acetate, the dichalcogenides remained intact and trimeric clusters of the composition [Ni-μ2-κ2-(Ni{κ5-LY}2)2-μ2-(OAc)2] (Y = Se, Te) were formed. Air oxidation and hydrolysis of [Ni-μ2-κ2-(Ni{κ5-LTe}2)2-μ2-(OAc)2] gave a rare example of a hexanuclear nickel cluster of the composition [Ni2-κ5-(Ni4-κ6-μ6-{(L'Te2O3)(L'TeO2)2}2)-μ2-(H2O)2], which is composed of a well-defined framework consisting of tellurinic anhydride and tellurinate units, which proves the comparably higher oxidation sensitivity of the trinickel dichalcogenide complexes. Electron spray ionization mass spectrometry spectra of both the palladium and nickel clusters indicate that they show fluctional behavior with varying nuclearity in solution and can adopt multiple charge states especially because of the noninnocence of the chalcogen-based ligands. The complexes were fully characterized by spectroscopic methods, elemental analyses, and X-ray diffraction.

Biomimetic crosslinking of collagen gels by energetic electrons: The role of L-lysine

Energetic electrons have recently evolved as a powerful tool for crosslinking bio-derived hydrogels without the need for adding potentially hazardous reagents. Application of this approach allows for synthesis of biomimetic collagen-derived networks of highly tunable properties and functionalization. Yet, the underlying reaction kinetics are still not sufficiently established at this point. While hydroxyl radicals are generated by energetic electron-induced hydrolysis of water and play a key role in introducing covalent bonds between network fibers, a detailed mechanistic understanding would significantly increase applicability. We present a comprehensive analysis of central aspects of the reactivity between the hydroxyl radical (•OH) and collagen, elastin, glycine (Gly) and l-lysine (Lys). Pulse radiolysis (PR), solid state nuclear magnetic resonance (NMR), ultraviolet-visible absorption spectroscopy (UV/VIS) and electron spray ionization mass spectrometry (ESI-MS) shine light on distinct features of the crosslinking process. These highlight retained protein backbone integrity in collagen and elastin whilst Lys's ability to form several imine bonded Lys-Lys-species suggests striking similarities to crosslinking via lysyl oxidase catalysis in vivo. Thus, energetic electron based crosslinking opens the venue for customized hybrid gels of outstanding biomimicry and –compatibility. Statement of significanceEnergetic electron beam treatment constitutes a highly attractive approach to establish chemical bonds between (bio) molecules. Although a convincing number of publications showed the versatility regarding crosslinking of bioderived hydrogels, insights into the underlying chemistry are still unestablished at this point. The present work unravels the mechanistics of energetic electron induced processes in collagen and elastin hydrogels as well as several abundant amino acids in aqueous solution. As key finding we demonstrate, that i) the connection between polymer chains is dominated by amino acid side chain interaction and ii) two single l-lysine molecules form an imine bond between the terminal amino group of one molecule and the delta carbon of the second molecule. We also consider the formation of H-bonds as a second crosslinking pathway. These findings open up for advanced, optionally spatially resolved biomaterials design.

Bioactive Molecules for Discriminating Robinia and Helianthus Honey: High-Performance Liquid Chromatography-Electron Spray Ionization-Mass Spectrometry Polyphenolic Profile and Physicochemical Determinations.

Bioactive molecules from the class of polyphenols are secondary metabolites from plants. They are present in honey from nectar and pollen of flowers from where honeybees collect the “raw material” to produce honey. Robinia pseudoacacia and Helianthus annuus are important sources of nectar for production of two monofloral honeys with specific characteristics and important biological activity. A high-performance liquid chromatography–electro spray ionization–mass spectrometry (HPLC–ESI–MS) separation method was used to determine polyphenolic profile from the two types of Romanian unifloral honeys. Robinia and Helianthus honey showed a common flavonoid profile, where pinobanksin (1.61 and 1.94 mg/kg), pinocembrin (0.97 and 1.78 mg/kg) and chrysin (0.96 and 1.08 mg/kg) were identified in both honey types; a characteristic flavonoid profile in which acacetin (1.20 mg/kg), specific only for Robinia honey, was shown; and quercetin (1.85 mg/kg), luteolin (21.03 mg/kg), kaempferol (0.96 mg/kg) and galangin (1.89 mg/kg), specific for Helianthus honey, were shown. In addition, different phenolic acids were found in Robinia and Helianthus honey, while abscisic acid was found only in Robinia honey. Abscisic acid was correlated with geographical location; the samples collected from the south part of Romania had higher amounts, due to climatic conditions. Acacetin was proposed as a biochemical marker for Romanian Robinia honey and quercetin for Helianthus honey.