There is a lot of evidence showing that lipid peroxidation plays very important role in development of various diseases, including neurodegenerative diseases and brain tumors. Lipid peroxidation is ...achieved by two main pathways, by enzymatic or by non-enzymatic oxidation, respectively. In this paper, we focus on non-enzymatic, self-catalyzed chain reaction of poly-unsaturated fatty acid (PUFA) peroxidation generating reactive aldehydes, notably 4-hydroxynonenal (4-HNE), which acts as second messenger of free radicals and as growth regulating factor. It might originate from astrocytes as well as from blood vessels, even within the blood-brain barrier (BBB), which is in case of brain tumors transformed into the blood-brain-tumor barrier (BBTB). The functionality of the BBB is strongly affected by 4-HNE because it forms relatively stable protein adducts thus allowing the persistence and the spread of lipid peroxidation, as revealed by immunohistochemical findings. Because 4-HNE can act as a regulator of vital functions of normal and of malignant cells acting in the cell type- and concentration-dependent manners, the bioactivities of this product of lipid peroxidation be should further studied to reveal if it acts as a co-factor of carcinogenesis or as natural factor of defense against primary brain tumors and metastatic cancer.
•Lipid peroxidation (LPO) plays important roles in the development of primary and metastatic brain tumors.•Its origin might be from astrocytes as well as from blood vessels, also within the BBB.•The LPO product 4-HNE allows persistence and spread of LPO acting as the second messenger of free radicals.•4-HNE acts as regulator of vital functions of normal and of malignant cells, also affecting the functionality of the BBB.•By acting through 4-HNE the LPO may be co-factor of carcinogenesis or/and a factor of defence against cancer.
The propensity of 4-hydroxybenzhydrazone-related ligands derived from 3-methoxysalicylaldehyde (H
L
), 4-methoxysalicylaldehyde (H
L
), and salicylaldehyde (H
L
) to act as chelating and/or bridging ...ligands in Ni(II) complexes was investigated. Three clusters of different nuclearities, Ni
(L
)
(OAc)
(MeOH)
∙2MeOH∙MeCN (
∙2MeOH∙MeCN), Ni
(HL
)(L
)(OAc)(MeOH)
∙4.7MeOH (
∙4.7MeOH), and Ni
(HL
)
(L
)
(OAc)
∙4MeOH·0.63H
O·0.5MeCN·HOAc (
∙4MeOH·0.63H
O·0.5MeCN·HOAc), were prepared from Ni(OAc)
∙4H
O and the corresponding ligand in the presence of Et
N. The hydrazones in these acetato- and phenoxido-bridged clusters acted as singly or doubly deprotonated ligands. When pyridine was used, mononuclear complexes with the square-planar geometry seemed to be favoured, as found for complexes Ni(L
)(py) (
), Ni(L
)(py) (
) and Ni(L
)(py) (
). Ligand substituent effects and the stability of square-planar complexes were investigated and quantified by extensive quantum chemical analysis. Obtained results showed that standard Gibbs energies of binding were lower for square-planar than for octahedral complexes. Starting from MoO
(L)(EtOH) complexes as precursors and applying the metal-exchange procedure, the mononuclear complexes Ni(HL
)
∙MeOH (
∙MeOH) and Ni(HL
)∙2MeOH (
∙2MeOH) and hybrid organic-inorganic compound Ni
(HL
)
(CH
OH)
Mo
O
(OCH
)
(
) were achieved. The octahedral complexes Ni(HL)
(
-
) can also be obtained by the direct synthesis from Ni(Oac)
∙4H
O and the appropriate ligand under specific reaction conditions. Crystal and molecular structures of
∙2MeOH∙MeCN,
∙4.7MeOH,
∙4MeOH∙0.63H
O∙0.5MeCN∙HOAc,
,
,
∙2MeOH, and
were determined by the single-crystal X-ray diffraction method.
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•Subcritical water extraction was employed to obtain extract of wild garlic.•Influence of process parameters on extraction of bioactive compounds was analyzed.•Optimal conditions for ...production oh highest quality extracts were determined.•Formation of Maillard reaction products during SWE was investigated.
Subcritical water extraction (SWE) was employed in order to obtain high valuable extracts from wild garlic (Allium ursinum). The influence of temperature (120–200°C), extraction time (10–30min) and added acidifier, HCl (0–1.5%) on extraction process was investigated. Analysis of variance was used to determine the fitness of the model and optimal process parameters for SWE, in order to maximize extraction yield, total phenolic compounds and total flavonoids content, and antioxidant activity. The optimal conditions for SWE were determined at temperature of 180.92°C, extraction time of 10min, and added acidifier at 1.09%. An insight into the development of Maillard reaction products during SWE was provided through measurement of 5-hydroximethylfurfural(5-HMF) and furfural (F)in all obtained extracts. No influence of 5-HMF and F on antioxidant activity was observed. Using HPLC-DAD, kaempferol derivates were identified as the major phenolic compounds in extract obtained at optimal condition.
Blood brain barrier (BBB) is a dynamic interface responsible for proper functioning of brain, but also a major obstacle for effective treatment of neurological diseases. Increased levels of free ...radicals, in high ferrous and high lipid content surrounding, induce lipid peroxidation, leading to production of 4-hydroxynonenal (HNE). HNE modifies all key proteins responsible for proper brain functioning thus playing a major role in the onset of neurological diseases. To investigate HNE effects on BBB permeability, we developed two in vitro BBB models-'physiological' and 'pathological'. The latter mimicked HNE modified extracellular matrix under oxidative stress conditions in brain pathologies. We showed that exogenous HNE induce activation of antioxidative defense systems by increasing catalase activity and glutathione content as well as reducing lipid peroxide levels in endothelial cells and astrocytes of 'physiological' model. While in 'pathological' model, exogenous HNE further increased lipid peroxidation levels of endothelial cells and astrocytes, followed by increase in Nrf2 and glutathione levels in endothelial cells. At lipid composition level, HNE caused increase in ω3 polyunsaturated fatty acid (PUFA) level in endothelial cells, followed by decrease in ω3 PUFA level and increase in monounsaturated fatty acid level in astrocytes. Using these models, we showed for the first time that HNE in 'pathological' model can reduce BBB permeability.
The paper describes synthesis of several novel thiosemicarbazone derivatives. Furthermore, crystal and molecular structure of 4-diethylamino-salicylaldehyde 4-phenylthiosemicarbazone revealed ...planarity of conjugated aromatic system, which suggested the possibility of DNA binding by intercalation, especially for here studied naphthalene derivatives. However, here presented DNA binding studies excluded this mode of action. Physicochemical and structural properties of novel derivatives were compared with previously studied analogues, taken as reference compounds, revealing distinctive differences. In addition, novel thiosemicarbazone derivatives (
1,
2 and
5–
8) clearly display stronger antiproliferative activity on five tumor cell lines than the reference compounds
3 and
4, which supports their further investigation as potential antitumor agents.
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•Utilization of sage herbal dust as raw material for extraction.•Evaluation of subcritical water extraction effects (temperature, time and HCl conc.).•Improvements in yields of ...extracted polyphenols and antioxidant activity.•Mathematical modeling of sage extraction process—RSM approach.•Determination of optimal conditions for maximizing response yields.
In this work, subcritical water extraction (SWE) of polyphenols from sage (Salvia officinalis L.) herbal dust was optimized by simultaneous maximization of total phenols (TP) and total flavonoids (TF) yields, as well as maximized antioxidant activity, determined by DPPH, ABTS and reducing power assay. Sage herbal dust, discarded as by-product from filter tea factory, was used as raw material for extraction. Three level, three variables, Box-Behnken experimental design (BBD) with response surface methodology (RSM) was used for optimization of SWE. Temperature (X1: 120–220°C), extraction time (X2: 10–30min) and HCl concentration in extraction solvent (X3: 0–1.5%) were investigated as independent variables. Experimentally obtained values were fitted to a second-order polynomial model, and multiple regression analysis and analysis of variance (ANOVA) were used to determine model fitness and optimal conditions. The optimal SWE conditions for simultaneous maximization of TP, TF and antioxidant activity were temperature of 201.5°C, extraction time of 15.8min and pure water as extraction solvent, while predicted values of TP, TF, IC50, TEAC and EC50 at this experimental point were 7.98g GAE/100g DW, 4.93g CE/100g DW, 13.38μg/mL, 38.34mM Trolox/100g DW and 41.66μg/mL, respectively. Results suggested that SWE provided significant advantages in terms of polyphenols yield, comparing to maceration, and that herbal dust from filter tea factory could be potentially utilized as good raw material for extraction of valuable bioactive compounds.
Flexible 1,5-bis(salicilydene)carbohydrazone ligand in combination with an in situ formed divanadium V2O34+ core afforded one discrete tetranuclear complex and two polymeric chain-like architectures, ...mutually related as supramolecular isomers. The occurrence of a particular isomer was controlled through the reaction conditions. All isolated products were structurally characterized via X-ray diffraction and infrared spectroscopy, while the relative stability of the architectures was assessed via competitive slurry and thermal experiments. This study highlights the adaptability of oxovanadium species towards the coordination “inventory” of building blocks present in the environment, while at the same time it unveils the richness of assembly modes of the related structural units.
The present study was conducted to develop subcritical water extraction (SWE) of Echinacea purpurea flowers. The influence of temperature and extraction time on quality of extracts considering total ...phenols content, total flavonoids content, antioxidant capacity and extraction yield, was determined. Optimized extraction parameters for maximised investigated responses were as follows: 147.56 °C and 8.43 min. The experimental values agreed with the values predicted, thus indicating the adequacy of central composite experimental design for modelling the SWE of bioactive compounds from E. purpurea. Results of the study also highlighted the potential application of E. purpurea subcritical water extracts as a source of valuable bioactive compounds.
This work presents a successful application of a recently reported supramolecular strategy for stabilization of metastable tautomers in cocrystals to monocomponent, non‐heterocyclic, tautomeric ...solids. Quantum‐chemical computations and solution studies show that the investigated Schiff base molecule, derived from 3‐methoxysalicylaldehyde and 2‐amino‐3‐hydroxypyridine (ap), is far more stable as the enol tautomer. In the solid state, however, in all three obtained polymorphic forms it exists solely as the keto tautomer, in each case stabilized by an unexpected hydrogen‐bonding pattern. Computations have shown that hydrogen bonding of the investigated Schiff base with suitable molecules shifts the tautomeric equilibrium to the less stable keto form. The extremes to which supramolecular stabilization can lead are demonstrated by the two polymorphs of molecular complexes of the Schiff base with ap. The molecules of both constituents of molecular complexes are present as metastable tautomers (keto anion and protonated pyridine, respectively), which stabilize each other through a very strong hydrogen bond. All the obtained solid forms proved stable in various solid‐state and solvent‐mediated methods used to establish their relative thermodynamic stabilities and possible interconversion conditions.
A stable relationship? The imine compound derived from 3‐methoxysalicylaldehyde and 2‐amino‐3‐hydroxypyridine crystallizes in three polymorphic forms, exclusively as a metastable keto–amino tautomer (see figure). Computations show that hydrogen bonding of the imine compound with suitable molecules shifts the tautomeric equilibrium to the less stable keto form, which was further used to obtain two metastable tautomers in multicomponent salts of the imine.
Complex salts 1HX and 1H(XA)0.5·2MeOH, and co-crystals 1HX·0.5VA (X = chloride or bromide, XA = chloranilate or bromanilate, VA = o-vanillin azine), comprising MoO2(HL)(MeOH)+ (1H+) cation (H2L = ...3-methoxysalicylaldehyde isonicotinoyl hydrazone), were prepared either by solution-based synthesis or by mechanochemical synthesis. Whereas 1HX salts were extremely sensitive to humidity, their stability could be reinforced by the azine incorporation into the complex network. Solvent-mediated transformations of 1HX led to methanol co-ligand replacement and afforded complexes MoO2(HL)X (2Cl·MeOH, 2Cl, and 2Br·0.5MeCN). However, solvates 1H(XA)0.5·2MeOH, under the same conditions, gave stable complexes 1H(XA)0.5 in which methanol remained coordinated. The differences in the assembly’s behavior were attributed to the packing arrangements, the relative orientation of cations and anions, and interactions between them. Polymorph MoO2(L)(MeOH) (1), not attainable by other routes, was the only product when compounds MoO2(HL)X were treated with a weak base at low temperatures. Tetranuclear MoO2(L)4 and polynuclear MoO2(L)n (2) supramolecular isomers, concomitantly crystallized when the reaction was conducted solvothermally. All of the complexes were characterized using X-ray diffraction methods (SCXRD and PXRD), spectroscopic methods (ATR-IR and solution-state and solid-state MAS NMR), and elemental and thermal analyses. The cytotoxicity of the different types of compounds against THP-1 and HepG2 cells was also evaluated.
