Hydrogen sulfide (H2S) is an endogenous gasotransmitter with cardioprotective and antiviral effects. In this work, new cysteine-selective nucleoside-H2S-donor hybrid molecules were prepared by conjugating nucleoside biomolecules with a thiol-activatable dithioacetyl group. 5'-Dithioacetate derivatives were synthesized from the canonical nucleosides (uridine, adenosine, cytidine, guanosine and thymidine), and the putative 5'-thio metabolites were also produced from uridine and adenosine. According to our measurements made with an H2S-specific sensor, nucleoside dithioacetates are moderately fast H2S donors, the guanosine derivative showed the fastest kinetics and the adenosine derivative the slowest. The antioxidant activity of 5'-thionucleosides is significantly higher than that of trolox, but lower than that of ascorbic acid, while intact dithioacetates have no remarkable antioxidant effect. In human Calu cells, the guanosine derivative showed a moderate anti-SARS-CoV-2 effect which was also confirmed by virus yield reduction assay. Dithioacetyl-adenosine and its metabolite showed similar acute cardiac effects as adenosine, however, it is noteworthy that both 5'-thio modified adenosines increased left ventricular ejection fraction or stroke volume, which was not observed with native adenosine.

• Klíčová slova
• Antioxidant, Antiviral, Dithioacetate, H2S donor, H2S release kinetics, Nucleoside, SARS-CoV-2,
• MeSH
• acetáty * farmakologie   chemie   chemická syntéza   MeSH
• antioxidancia * farmakologie   chemická syntéza   chemie   MeSH
• antivirové látky * farmakologie   chemická syntéza   chemie   MeSH
• krysa rodu Rattus MeSH
• lidé MeSH
• nukleosidy * farmakologie   chemie   chemická syntéza   MeSH
• SARS-CoV-2 účinky léků   MeSH
• sulfan * metabolismus   chemie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• lidé MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• acetáty * MeSH
• antioxidancia * MeSH
• antivirové látky * MeSH
• nukleosidy * MeSH
• sulfan * MeSH

A series of potassium isothiocyanato-(N-salicylidene-aminoacidato) cuprates (1-5) with the general formula of the monomeric unit K[Cu(sal-aa)(NCS)] ⋅ xH2O (x=0 or 2), containing a Schiff-base ligand (H2sal-aa) derived from natural amino acids such as glycine, DL-α-alanine, DL-valine, DL-phenylalanine and β-alanine, and salicylaldehyde, was screened for in vitro antiradical and major cellular effects against selected cancerous and normal cells. The complexes exhibited strong antioxidant properties against superoxide in vitro and a protective effect on DNA under Fenton-like reaction conditions. Screening of their cellular effects revealed moderate in vitro cytotoxicity against human cancer cell lines (A2780, A2780R and MCF-7), with IC50 values of 25-35 μM, and relatively low toxicity to normal fibroblast MRC-5 cells (with IC50 values>50 μM). Additional experiments performed on A2780 cells revealed that the most potent complex 5 significantly increased the number of A2780 cells arrested in the G2/M phase of the cell cycle and triggered intracellular oxidative stress. The selected flow cytometry experiments (detection of apoptosis/autophagy and activation of caspases 3/7 and depletion of mitochondrial membrane potential) did not reveal the dominant mechanism underlying the cytotoxicity of the complexes but clearly differentiated their molecular effects from those of the reference drug cisplatin. All the complexes exerted anti-inflammatory effects by modulating the levels of the proinflammatory cytokines TNF-α and IL-1β in LPS-activated THP-1 macrophage-like cells. Complex 5 also slightly influenced the activity of the upstream NF-κB transcription factor, while no effect on PPARγ activation was detected.

• Klíčová slova
• Cellular effects, Copper complex, Cytotoxicity, Inflammation, Schiff base,
• MeSH
• antiflogistika nesteroidní farmakologie   chemie   chemická syntéza   MeSH
• antiflogistika farmakologie   chemie   chemická syntéza   MeSH
• antioxidancia farmakologie   chemie   chemická syntéza   MeSH
• apoptóza účinky léků   MeSH
• kationty chemie   farmakologie   MeSH
• komplexní sloučeniny * farmakologie   chemie   chemická syntéza   MeSH
• lidé MeSH
• měď * chemie   farmakologie   MeSH
• molekulární struktura MeSH
• nádorové buněčné linie MeSH
• proliferace buněk * účinky léků   MeSH
• protinádorové látky * farmakologie   chemie   chemická syntéza   MeSH
• Schiffovy báze * chemie   farmakologie   chemická syntéza   MeSH
• screeningové testy protinádorových léčiv * MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antiflogistika nesteroidní MeSH
• antiflogistika MeSH
• antioxidancia MeSH
• kationty MeSH
• komplexní sloučeniny * MeSH
• měď * MeSH
• protinádorové látky * MeSH
• Schiffovy báze * MeSH

A combination of several pharmacophores in one molecule has been successfully used for multi-target-directed ligands (MTDL) design. New propargylamine substituted derivatives combined with salicylic and cinnamic scaffolds were designed and synthesized as potential cholinesterases and monoamine oxidases (MAOs) inhibitors. They were evaluated invitro for inhibition of acetyl- (AChE) and butyrylcholinesterase (BuChE) using Ellman's method. All the compounds act as dual inhibitors. Most of the derivatives are stronger inhibitors of AChE, the best activity showed 5-bromo-N-(prop-2-yn-1-yl)salicylamide 1e (IC50 = 8.05 µM). Carbamates (4-bromo-2-[(prop-2-yn-1-yl)carbamoyl]phenyl ethyl(methyl)carbamate 2d and 2,4-dibromo-6-[(prop-2-yn-1-yl)carbamoyl]phenyl ethyl(methyl)carbamate 2e were selective and the most active for BuChE (25.10 and 26.09 µM). 4-Bromo-2-[(prop-2-yn-1-ylimino)methyl]phenol 4a was the most potent inhibitor of MAOs (IC50 of 3.95 and ≈10 µM for MAO-B and MAO-A, respectively) along with a balanced inhibition of both cholinesterases being a real MTDL. The mechanism of action was proposed, and binding modes of the hits were studied by molecular docking on human enzymes. Some of the derivatives also exhibited antioxidant properties. Insilico prediction of physicochemical parameters affirm that the molecules would be active after oral administration and able to reach brain tissue.

• Klíčová slova
• Acetylcholinesterase, Butyrylcholinesterase, Enzyme inhibition, Molecular docking, Monoamine oxidases, Multitargeting ligands, Propargylamine, Salicylic scaffold,
• MeSH
• antioxidancia chemická syntéza   chemie   farmakologie   MeSH
• butyrylcholinesterasa metabolismus   MeSH
• cholinesterasové inhibitory chemická syntéza   chemie   farmakologie   MeSH
• cholinesterasy metabolismus   MeSH
• Electrophorus MeSH
• hepatocyty účinky léků   metabolismus   MeSH
• inhibitory MAO chemická syntéza   chemie   farmakologie   MeSH
• koně MeSH
• krysa rodu Rattus MeSH
• kultivované buňky MeSH
• lidé MeSH
• molekulární struktura MeSH
• monoaminoxidasa metabolismus   MeSH
• pargylin analogy a deriváty   chemická syntéza   chemie   farmakologie   MeSH
• potkani Wistar MeSH
• propylaminy chemická syntéza   chemie   farmakologie   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• simulace molekulového dockingu * MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• lidé MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antioxidancia MeSH
• butyrylcholinesterasa MeSH
• cholinesterasové inhibitory MeSH
• cholinesterasy MeSH
• inhibitory MAO MeSH
• monoaminoxidasa MeSH
• pargylin MeSH
• propargylamine MeSH Prohlížeč
• propylaminy MeSH
• reaktivní formy kyslíku MeSH

Silver nanoparticles (Ag. NPs) have shown a biological activity range, synthesized under different environment-friendly approaches. Ag. NPs were synthesized using aqueous crude extract (ACE) isolated from Plantago lanceolata. The ACE and Ag. NPs were characterized and assessed their biological and antioxidant activities. The existence of nanoparticles (NPs) was confirmed by color shift, atomic force microscopy (AFM), and UV-Vis's spectroscopy. The FT-IR analysis indicated the association of biomolecules (phenolic acid and flavonoids) to reduce silver (Ag+) ions. The SEM study demonstrated a sphere-shaped and mean size in the range of 30 ± 4 nm. The EDX spectrum revealed that the Ag. NPs were composed of 54.87% Ag with 20 nm size as identified by SEM and TEM. AFM has ended up being exceptionally useful in deciding morphological elements and the distance across of Ag. NPs in the scope of 23-30 nm. The TEM image showed aggregations of NPs and physical interaction. Ag. NPs formation also confirmed by XPS, DRS and BET studies. Ag. NPs showed efficient activity as compared to ACE, and finally, the bacterial growth was impaired by biogenic NPs. The lethal dose (LD50) of Ag. NPs against Agrobacterium tumefaciens, Proteus vulgaris, Staphylococcus aureus, and Escherichia coli were 45.66%, 139.71%, 332.87%, and 45.54%, with IC50 (08.02 ± 0.68), (55.78 ± 1.01), (12.34 ± 1.35) and (11.68 ± 1.42) respectively, suppressing the growth as compared to ACE. The antioxidant capacity, i.e., 2,2-diphenyl-1-picrylhydrazyl (DPPH) of Ag. NPs were assayed. ACE and Ag. NPs achieved a peak antioxidant capacity of 62.43 ± 2.4 and 16.85 ± 0.4 μg mL-1, compared to standard (69.60 ± 1.1 at 100 μg mL-1) with IC50 (369.5 ± 13.42 and 159.5 ± 10.52 respectively). Finally, the Ag. NPs synthesized by P. lanceolata extract have an excellent source of bioactive natural products (NP). Outstanding antioxidant, antibacterial activities have been shown by NPs and can be used in various biological techniques in future research.

• MeSH
• antibakteriální látky chemická syntéza   chemie   farmakologie   MeSH
• antioxidancia chemická syntéza   chemie   farmakologie   MeSH
• Bacteria účinky léků   MeSH
• bakteriální infekce farmakoterapie   MeSH
• kovové nanočástice chemie   ultrastruktura   MeSH
• lidé MeSH
• nanotechnologie MeSH
• Plantago chemie   MeSH
• stříbro chemie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• odvolaná publikace MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antibakteriální látky MeSH
• antioxidancia MeSH
• stříbro MeSH

We synthesized eleven new amiridine-piperazine hybrids 5a-j and 7 as potential multifunctional agents for Alzheimer's disease (AD) treatment by reacting N-chloroacetylamiridine with piperazines. The compounds displayed mixed-type reversible inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Conjugates were moderate inhibitors of equine and human BChE with negligible fluctuation in anti-BChE activity, whereas anti-AChE activity was substantially dependent on N4-substitution of the piperazine ring. Compounds with para-substituted aromatic moieties (5g, 5h, and bis-amiridine 7) had the highest anti-AChE activity in the low micromolar range. Top-ranked compound 5h, N-(2,3,5,6,7,8-hexahydro-1H-cyclopenta[b]quinolin-9-yl)-2-[4-(4-nitro-phenyl)-piperazin-1-yl]-acetamide, had an IC50 for AChE = 1.83 ± 0.03 μM (Ki = 1.50 ± 0.12 and αKi = 2.58 ± 0.23 μM). The conjugates possessed low activity against carboxylesterase, indicating a likely absence of unwanted drug-drug interactions in clinical use. In agreement with analysis of inhibition kinetics and molecular modeling studies, the lead compounds were found to bind effectively to the peripheral anionic site of AChE and displace propidium, indicating their potential to block AChE-induced β-amyloid aggregation. Similar propidium displacement activity was first shown for amiridine. Two compounds, 5c (R = cyclohexyl) and 5e (R = 2-MeO-Ph), exhibited appreciable antioxidant capability with Trolox equivalent antioxidant capacity values of 0.47 ± 0.03 and 0.39 ± 0.02, respectively. Molecular docking and molecular dynamics simulations provided insights into the structure-activity relationships for AChE and BChE inhibition, including the observation that inhibitory potencies and computed pKa values of hybrids were generally lower than those of the parent molecules. Predicted ADMET and physicochemical properties of conjugates indicated good CNS bioavailability and safety parameters comparable to those of amiridine and therefore acceptable for potential lead compounds at the early stages of anti-AD drug development.

• Klíčová slova
• ADMET, Acetylcholinesterase (AChE), Alzheimer’s disease (AD), Amiridine, Butyrylcholinesterase (BChE), Molecular docking, Molecular dynamics (MD) simulations, Multifunctional agents, Piperazine,
• MeSH
• acetylcholinesterasa metabolismus   MeSH
• Alzheimerova nemoc farmakoterapie   metabolismus   MeSH
• aminochinoliny chemie   farmakologie   MeSH
• antioxidancia chemická syntéza   chemie   farmakologie   MeSH
• benzothiazoly antagonisté a inhibitory   MeSH
• butyrylcholinesterasa metabolismus   MeSH
• cholinesterasové inhibitory chemická syntéza   chemie   farmakologie   MeSH
• koně MeSH
• kyseliny sulfonové antagonisté a inhibitory   MeSH
• lidé MeSH
• molekulární modely MeSH
• molekulární struktura MeSH
• neuroprotektivní látky chemická syntéza   chemie   farmakologie   MeSH
• oxidační stres účinky léků   MeSH
• piperazin chemie   farmakologie   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid MeSH Prohlížeč
• acetylcholinesterasa MeSH
• aminochinoliny MeSH
• amiridine MeSH Prohlížeč
• antioxidancia MeSH
• benzothiazoly MeSH
• butyrylcholinesterasa MeSH
• cholinesterasové inhibitory MeSH
• kyseliny sulfonové MeSH
• neuroprotektivní látky MeSH
• piperazin MeSH

A small library of 2-[(1H-indol-3-yl)methyl]-5-(alkylthio)-1,3,4-oxadiazoles was prepared, starting from indole-3-acetic acid methyl ester and its 5-methyl-substituted derivative. The synthetic route involved the formation of intermediate hydrazides, their condensation with carbon disulfide, and intramolecular cyclization to corresponding 5-[(1H-indol-3-yl)methyl]-1,3,4-oxadiazole-2(3H)-thiones. The latter were then S-alkylated, and in case of ester derivatives, they were further hydrolyzed into corresponding carboxylic acids. All 5-[(1H-indol-3-yl)methyl]-1,3,4-oxadiazole-2(3H)-thiones and their S-alkylated derivatives were then screened for their protective effects in vitro and in vivo. Methyl substitution on the indole ring and propyl, butyl, or benzyl substitution on sulfhydryl group-possessing compounds were revealed to protect Friedreich's ataxia fibroblasts against the effects of glutathione depletion induced by the γ-glutamylcysteine synthetase inhibitor, buthionine sulfoximine. Two of the active compounds also reproducibly increased the survival of Caenorhabditis elegans exposed to juglone-induced oxidative stress.

• Klíčová slova
• Caenorhabditis elegans, Friedreich's ataxia, indole, oxadiazole, oxidative stress,
• MeSH
• acetáty chemická syntéza   MeSH
• antioxidancia * chemická syntéza   chemie   farmakologie   MeSH
• Caenorhabditis elegans MeSH
• Friedreichova ataxie farmakoterapie   metabolismus   patologie   MeSH
• indoly * chemie   farmakologie   MeSH
• kultivované buňky MeSH
• kyseliny indoloctové chemie   MeSH
• lidé MeSH
• oxadiazoly * chemická syntéza   chemie   farmakologie   MeSH
• oxidační stres účinky léků   MeSH
• thioketony * chemická syntéza   chemie   farmakologie   MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• acetáty MeSH
• antioxidancia * MeSH
• indole MeSH Prohlížeč
• indoleacetic acid MeSH Prohlížeč
• indoly * MeSH
• kyseliny indoloctové MeSH
• oxadiazoly * MeSH
• thioketony * MeSH

There are numerous studies supporting the contribution of oxidative stress to the pathogenesis of epilepsy. Prolonged oxidative stress is associated with the overexpression of ATP-binding cassette transporters, which results in antiepileptic drugs resistance. During our studies, three 1,2,4-triazole-3-thione derivatives were evaluated for the antioxidant activity and anticonvulsant effect in the 6 Hz model of pharmacoresistant epilepsy. The investigated compounds exhibited 2-3 times more potent anticonvulsant activity than valproic acid in 6 Hz test in mice, which is well-established preclinical model of pharmacoresistant epilepsy. The antioxidant/ROS scavenging activity was confirmed in both single-electron transfer-based methods (DPPH and CUPRAC) and during flow cytometric analysis of total ROS activity in U-87 MG cells. Based on the enzymatic studies on human carbonic anhydrases (CAs), acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), one can assume that the herein investigated drug candidates will not impair the cognitive processes mediated by CAs and will have minimal off-target cholinergic effects.

• Klíčová slova
• 6 Hz psychomotor seizures, carbonic anhydrases, cholinesterase inhibitors, mitochondrial potential, total ROS activity,
• MeSH
• acetylcholinesterasa metabolismus   MeSH
• antikonvulziva chemická syntéza   chemie   farmakologie   MeSH
• antioxidancia chemická syntéza   chemie   farmakologie   MeSH
• bifenylové sloučeniny antagonisté a inhibitory   MeSH
• butyrylcholinesterasa metabolismus   MeSH
• cholinesterasové inhibitory chemická syntéza   chemie   farmakologie   MeSH
• epilepsie farmakoterapie   metabolismus   MeSH
• inhibitory karboanhydras chemická syntéza   chemie   farmakologie   MeSH
• karboanhydrasy metabolismus   MeSH
• lidé MeSH
• molekulární modely MeSH
• molekulární struktura MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• oxidační stres účinky léků   MeSH
• pikráty antagonisté a inhibitory   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• triazoly chemická syntéza   chemie   farmakologie   MeSH
• viabilita buněk účinky léků   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 1,1-diphenyl-2-picrylhydrazyl MeSH Prohlížeč
• 1,2,4-triazole MeSH Prohlížeč
• acetylcholinesterasa MeSH
• antikonvulziva MeSH
• antioxidancia MeSH
• bifenylové sloučeniny MeSH
• butyrylcholinesterasa MeSH
• cholinesterasové inhibitory MeSH
• inhibitory karboanhydras MeSH
• karboanhydrasy MeSH
• pikráty MeSH
• reaktivní formy kyslíku MeSH
• triazoly MeSH

A series of 1,3,5-triazine analogues, incorporating aminobenzene sulfonamide, aminoalcohol/phenol, piperazine, chalcone, or stilbene structural motifs, were evaluated as potential antioxidants. The compounds were prepared by using step-by-step nucleophilic substitution of chlorine atoms in starting 2,4,6-trichloro-1,3,5-triazine. Reactions were catalyzed by Cu(I)-supported on a weakly acidic resin. The radical scavenging activity was determined in terms of %inhibition activity and EC50, using the ABTS method. Trolox and ascorbic acid (ASA) were used as standards. In the lowest concentration 1 × 10-4 M, the %inhibition activity values at 0 min were comparable with both standards at least for 10 compounds. After 60 min, compounds 5, 6, 13, and 25 showed nearly twice %inhibition (73.44-87.09%) in comparison with the standards (Trolox = 41.49%; ASA = 31.07%). Values of EC50 at 60 min (17.16-27.78 μM) were 5 times lower for compounds 5, 6, 13, and 25 than EC50 of both standards (trolox = 178.33 μM; ASA = 147.47 μM). Values of EC50 correlated with %inhibition activity. Based on these results, the presented 1,3,5-triazine analogues have a high potential in the treatment of illnesses caused or related to oxidative stress.

• Klíčová slova
• 1,3,5-triazine, 4-aminophenol, ABTS method, antioxidative activity, hydroxychalcone, hydroxystilbene,
• MeSH
• antioxidancia chemická syntéza   chemie   farmakologie   MeSH
• chalkon chemie   MeSH
• fenol chemie   MeSH
• molekulární struktura MeSH
• piperazin chemie   MeSH
• sulfonamidy chemie   MeSH
• techniky syntetické chemie MeSH
• triaziny chemická syntéza   chemie   farmakologie   MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antioxidancia MeSH
• chalkon MeSH
• fenol MeSH
• piperazin MeSH
• sulfonamidy MeSH
• triaziny MeSH

Cytokinins are naturally occurring substances that act as plant growth regulators promoting plant growth and development, including shoot initiation and branching, and also affecting apical dominance and leaf senescence. Aromatic cytokinin 6-benzylaminopurine (BAP) has been widely used in micropropagation systems and biotechnology. However, its 9-glucoside (BAP9G) accumulates in explants, causing root inhibition and growth heterogenity. To overcome BAP disadvantages, a series of ring-substituted 2'-deoxy-9-(β)-d-ribofuranosylpurine derivatives was prepared and examined in different classical cytokinin bioassays. Amaranthus, senescence and tobacco callus bioassays were employed to provide details of cytokinin activity of 2'-deoxy-9-(β)-d-ribosides compared to their respective free bases and ribosides. The prepared derivatives were also tested for their recognition by cytokinin receptors of Arabidopsis thaliana AHK3 and CRE1/AHK4. The ability of aromatic N6-substituted adenine-2'-deoxy-9-(β)-d-ribosides to promote plant growth and delay senescence was increased considerably and, in contrast to BAP, no loss of cytokinin activity at higher concentrations was observed. The presence of a 2'-deoxyribosyl moiety at the N9-position led to an increase in cytokinin activities in comparison to the free bases and ribosides. The antioxidant capacity, cytotoxicity and effect on the MHV-68 gammaherpesvirus strain were also examined.

• Klíčová slova
• 2′-Deoxyribosides, Antioxidative capacity, Antiviral testing, Aromatic cytokinins, Plant growth regulator, Purine derivatives,
• MeSH
• antioxidancia chemická syntéza   chemie   farmakologie   MeSH
• Arabidopsis účinky léků   metabolismus   MeSH
• Cercopithecus aethiops MeSH
• molekulární struktura MeSH
• purinové nukleosidy chemická syntéza   chemie   farmakologie   MeSH
• regulátory růstu rostlin chemická syntéza   chemie   farmakologie   MeSH
• Vero buňky MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antioxidancia MeSH
• purinové nukleosidy MeSH
• regulátory růstu rostlin MeSH

The valorization of lignins as renewable aromatic feedstock is of utmost importance in terms of the use of sustainable resources. This study provides a deductive approach towards market-oriented lignin-derived antioxidants by ascertaining the direct effect of different structural features of lignin on the reactivity of its phenolic OH groups in the radical scavenging reactions. The antioxidant activity of a series of compounds, modeling lignin structural units, was experimentally characterized and rationalized, using thermodynamic descriptors. The calculated O-H bond dissociation enthalpies (BDE) of characteristic lignin subunits were used to predict the modification pathways of technical lignins. The last ones were isolated by soda delignification from different biomass sources and their oligomeric fractions were studied as a raw material for modification and production of optimized antioxidants. These were characterized in terms of chemical structure, molecular weight distribution, content of the functional groups, and the antioxidant activity. The developed approach for the targeted modification of lignins allowed the products competitive with two commercial synthetic phenolic antioxidants in both free radical scavenging and stabilization of thermooxidative destruction of polyurethane films.

• Klíčová slova
• antioxidant activity, lignins, modification, molecular rationalization, stabilizers for polymers,
• MeSH
• antioxidancia chemická syntéza   MeSH
• dimerizace MeSH
• elektrony MeSH
• kinetika MeSH
• lignin chemie   MeSH
• polyfenoly chemie   MeSH
• polyurethany chemie   MeSH
• protonová magnetická rezonanční spektroskopie MeSH
• spektroskopie infračervená s Fourierovou transformací MeSH
• teoretické modely * MeSH
• teorie funkcionálu hustoty * MeSH
• teplota MeSH
• vodík chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antioxidancia MeSH
• lignin MeSH
• polyfenoly MeSH
• polyurethany MeSH
• vodík MeSH