Antioxidatives are widely used and recommended in common clinical praxis, even though they may have negative impact on our health under some circumstances (i.e. N-acetylcysteine, vitamin E, risk of lung cancer etc.). Our aim was to evaluate the role of exogenous scavengers in prevention of induced oxidative stress in rodents. Male ICR mice were used and acute hypoglycaemia was induced with insulin. The mice were randomized into eight experimental groups, either pretreated by vitamin C or vitamin E or combinations with respective vehicles. Total malondialdehyde (MDA), superoxide dismutase (SOD), and selenium-dependent glutathione peroxidase (GSHPx) activity were measured in brain tissue samples. ANOVA with a post-hoc Duncan or Turkey׳s tests were used for statistical evaluation. A statistically significant increase in brain MDA was observed after insulin-induced severe hypoglycaemia relative to normoglycaemia. Animals pretreated with vitamins, both in monotherapy and in combination (both P<0.05), had significantly lower MDA values compared with animals without pretreatment. Importantly, significant differences were also observed after combination of vitamin C and E in GSHPx and SOD (both P<0.05).
- MeSH
- glutathionperoxidasa metabolismus MeSH
- hypoglykemie krev chemicky indukované farmakoterapie metabolismus MeSH
- inzulin MeSH
- kombinovaná farmakoterapie MeSH
- krevní glukóza analýza MeSH
- kyselina askorbová farmakologie terapeutické užití MeSH
- malondialdehyd metabolismus MeSH
- mozek účinky léků metabolismus MeSH
- myši inbrední ICR MeSH
- peroxidace lipidů účinky léků MeSH
- potravní doplňky MeSH
- superoxiddismutasa metabolismus MeSH
- vitamin E farmakologie terapeutické užití MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
NAG-thiazoline is a strong competitive inhibitor of GH20 β-N-acetyl- hexosaminidases and GH84 β-N-acetylglucosaminidases. Here, we focused on the design, synthesis and inhibition potency of a series of new derivatives of NAG-thiazoline modified at the C-6 position. Dimerization of NAG-thiazoline via C-6 attached triazole linkers prepared by click chemistry was employed to make use of multivalency in the inhibition. Novel compounds were tested as potential inhibitors of β-N-acetylhexosaminidases from Talaromyces flavus, Streptomyces plicatus (both GH20) and β-N-acetylglucosaminidases from Bacteroides thetaiotaomicron and humans (both GH84). From the set of newly prepared NAG-thiazoline derivatives, only C-6-azido-NAG-thiazoline displayed inhibition activity towards these enzymes; C-6 triazole-substituted NAG-thiazolines lacked inhibition activity against the enzymes used. Docking of C-6-azido-NAG-thiazoline into the active site of the tested enzymes was performed. Moreover, a stability study with GlcNAc-thiazoline confirmed its decomposition at pH < 6 yielding 2-acetamido-2-deoxy-1-thio-α/β-D-glucopyranoses, which presumably dimerize oxidatively into S-S linked dimers; decomposition products of NAG-thiazoline are void of inhibitory activity.
- MeSH
- acetylglukosamin analogy a deriváty chemická syntéza chemie farmakologie MeSH
- beta-N-acetylhexosaminidasy antagonisté a inhibitory chemie metabolismus MeSH
- glykosidhydrolasy antagonisté a inhibitory chemie metabolismus MeSH
- katalytická doména MeSH
- molekulární konformace MeSH
- molekulární modely MeSH
- stabilita léku MeSH
- thiazoly chemická syntéza chemie farmakologie MeSH
- vazba proteinů MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Divalent or multivalent molecules often show enhanced biological activity relative to the simple monomeric units. Here we present enzymatically and chemically prepared dimers of the flavonolignans silybin and 2,3-dehydrosilybin. Their electrochemical behavior was studied by in situ and ex situ square wave voltammetry. The oxidation of monomers and dimers was similar, but adsorption onto the electrode and cell surfaces was different. A 1,1-diphenyl-2-picrylhydrazyl (DPPH) and an inhibition of microsomal lipoperoxidation assay were performed with same trend of results for silybin and 2,3-dehydrosilybin dimers. Silybin dimer showed better activity than the monomer, while on the contrary 2,3-dehydrosilybin dimer presented weaker antioxidant/antilipoperoxidant activity than its monomer. Cytotoxicity was evaluated on human umbilical vein endothelial cells, normal human adult keratinocytes, mouse fibroblasts (BALB/c 3T3) and human liver hepatocellular carcinoma cell line (HepG2). Silybin dimer was more cytotoxic than the parent compound and in the case of 2,3-dehydrosilybin its dimer showed weaker cytotoxicity than the monomer.
- MeSH
- bifenylové sloučeniny antagonisté a inhibitory MeSH
- biokatalýza MeSH
- buňky Hep G2 MeSH
- dimerizace MeSH
- endoteliální buňky pupečníkové žíly (lidské) MeSH
- fibroblasty cytologie účinky léků MeSH
- fungální proteiny chemie MeSH
- jaterní mikrozomy účinky léků MeSH
- keratinocyty cytologie účinky léků MeSH
- krysa rodu rattus MeSH
- lidé MeSH
- lipasa chemie MeSH
- myši MeSH
- oxidace-redukce MeSH
- peroxidace lipidů účinky léků MeSH
- pikráty antagonisté a inhibitory MeSH
- scavengery volných radikálů chemická syntéza farmakologie MeSH
- silymarin chemická syntéza farmakologie MeSH
- viabilita buněk účinky léků MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Silybin and its congeners belong to a group of flavonolignans with strong biological activities. These compounds are potentially applicable in human medicine, e. g. due to their cytoprotective activity. As a part of herbal preparations available on the open market, they face the risk of potential negative drug-drug interactions. This review aims to evaluate current knowledge on the metabolism of these compounds by biotransformation enzymes, interactions with other drugs, their pharmacokinetics, and bioavailability. While silybin and its derivatives interact with cytochrome P450s, only metabolism of silybin by cytochrome P450 2C8 poses a risk of adverse effects. The main biotransformation route of silybin and derivatives was identified as conjugation, which is stereospecific in case of silybin. Studies of the metabolism, pharmacokinetics, potentional drug--drug interactions and increasing bioavailability of these flavonolignans play an important facet of possible therapeutical use of these compounds. The goal of our review is to aid future developments in the area of silybin research.
- MeSH
- antioxidancia chemie metabolismus farmakokinetika MeSH
- biologická dostupnost MeSH
- biotransformace MeSH
- glukuronidy metabolismus MeSH
- lidé MeSH
- silymarin analogy a deriváty chemie metabolismus farmakokinetika MeSH
- stereoizomerie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Aryl sulfotransferase IV (AstIV) from rat liver was overexpressed in Escherichia coli and purified to homogeneity. Using the produced mammalian liver enzyme, sulfation-the Phase II conjugation reaction-of optically pure silybin diastereoisomers (silybin A and B) was tested. As a result, silybin B was sulfated yielding 20-O-silybin B sulfate, whereas silybin A was completely resistant to the sulfation reaction. Milligram-scale sulfation of silybin B was optimized employing resting E. coli cells producing AstIV, thus avoiding the use of expensive 3'-phosphoadenosine-5'-phosphate cofactor and laborious enzyme purification. Using this approach, we were able to reach 48 % conversion of silybin B into its 20-sulfate within 24 h. The sulfated product was isolated by solid phase extraction and its structure was characterized by HRMS and NMR. Sulfation reaction of silybin appeared strictly stereoselective; only silybin B was sulfated by AstIV.
- MeSH
- antioxidancia metabolismus MeSH
- arylsulfotransferasa genetika izolace a purifikace metabolismus MeSH
- Escherichia coli genetika MeSH
- játra enzymologie MeSH
- krysa rodu rattus MeSH
- rekombinantní proteiny genetika izolace a purifikace metabolismus MeSH
- silymarin metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Extensive screening for a robust producer of α-L-rhamnosidase activity from well-defined strains of filamentous fungi, including multifactorial optimization (inducers, cultivation conditions) was accomplished. Enzyme production of the optimal producer Aspergillus terreus (non-toxigenic) was scaled up to 50L. α-L-Rhamnosidase, which was fully characterized, proved to be thermo- and alkali-tolerant, thus enabling effective operation at 70°C and pH 8.0. These conditions allow for a very high substrate (rutin) load up to 100-300 g/L, thus enabling very high volumetric productivity of the reaction product quercetin-3-β-D-glucopyranoside (isoquercitrin). Here, a novel concept of "immobilised substrate" is used. Isoquercitrin is a highly effective and biocompatible antioxidant with strong anti-inflammatory activities. Rutin biotransformation was optimized and scaled up to ca 10 kg production and thus the robustness of the large-scale production was demonstrated. Isoquercitrin can be produced to a very high purity (98%) in multikilogram amounts, without any quercetin and directly applicable in nutraceuticals.
- MeSH
- alkálie farmakologie MeSH
- Aspergillus účinky léků enzymologie MeSH
- beta-glukosidasa metabolismus MeSH
- bioreaktory mikrobiologie MeSH
- biotechnologie metody MeSH
- biotransformace účinky léků MeSH
- fyziologická adaptace účinky léků MeSH
- glukosidy biosyntéza chemie MeSH
- glykosidhydrolasy metabolismus MeSH
- koncentrace vodíkových iontů účinky léků MeSH
- quercetin analogy a deriváty biosyntéza chemie MeSH
- rutin chemie metabolismus MeSH
- stabilita enzymů účinky léků MeSH
- teplota MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The synthesis of various silybin monogalloyl esters was developed, and their antiangiogenic activities were evaluated in a variety of in vitro tests with human umbilical vein endothelial cells (HUVECs). A structure-activity relationship (SAR) study found the regioselectivity of the silybin galloylation to be highly significant. Silybin (as an equimolar mixture of two diastereomers A and B) exhibited quite poor antiangiogenic activities, whereas its B stereoisomer is more active than silybin A. The galloylation of phenolic OH groups of natural silybin (a mixture of both isomers) leads to increases in their antiangiogenic activities, which is more apparent with the 7-OH than the 20-OH. In contrast, gallates at aliphatic OH groups either had a comparable activity to the parent compound or are even worse than silybin, which was observed in the case of 3-O-galloylsilybin. The most effective compound from this series (7-O-galloylsilybin) has also been prepared from stereochemically pure silybins A and B to evaluate the effect of stereochemistry on the activity. As with silybin itself, the B isomer of 7-O-galloylsilybin was more active than the A isomer.
- MeSH
- buněčná diferenciace účinky léků MeSH
- endoteliální buňky pupečníkové žíly (lidské) MeSH
- endoteliální buňky účinky léků fyziologie MeSH
- estery MeSH
- fixní kombinace léků MeSH
- inhibitory angiogeneze chemická syntéza chemie farmakologie MeSH
- kolagen MeSH
- kyselina gallová analogy a deriváty chemická syntéza farmakologie MeSH
- laminin MeSH
- lidé MeSH
- pohyb buněk účinky léků MeSH
- proliferace buněk účinky léků MeSH
- proteoglykany MeSH
- silymarin analogy a deriváty chemická syntéza farmakologie MeSH
- stereoizomerie MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Two chromatographic narrow-bore columns, a novel 2.6 μm particle-packed Kinetex™ C18 core-shell (50×2.1 mm id) and monolithic Chromolith(®) FastGradient RP-18e (50×2 mm id), were evaluated for the analysis of diastereoisomers of the flavonolignans silybin and 23-O-acetylsilybin under isocratic conditions. The main advantages of the core-shell column are markedly higher efficiency (hmin =2.8 versus 5.6 for silybin A) and better peak symmetry. The Kinetex column exhibits only a slight change in the height equivalent of the theoretical plate with a higher linear velocity of the mobile phase. The monolithic column shows notably higher selectivity in terms of selectivity factor (1.21 versus 1.12) in the analysis of critical-pair of diastereoisomers (silybin A and silybin B) and enables shorter run duration (approx. twofold) together with lower backpressure. The resolution power was found to be comparable, but the Kinetex column required a higher pressure of the mobile phase that, together with the higher chance of clogging, can be a disadvantage in the separation of biological samples. Successful baseline separation of silybin diastereoisomers in real pharmaceutical sample on monolithic column was accomplished.
Two selective acylation methods for silybin esterification with long-chain fatty acids were developed, yielding a series of silybin 7-O- and 23-O-acyl-derivatives of varying acyl chain lengths. These compounds were tested for their antioxidant (inhibition of lipid peroxidation and DPPH-scavenging) and anti-influenza virus activities. The acyl chain length is an important prerequisite for both biological activities, as they improved with increasing length of the acyl moiety.
- MeSH
- acylace MeSH
- antioxidancia farmakologie MeSH
- antivirové látky farmakologie MeSH
- buněčné linie MeSH
- esterifikace MeSH
- magnetická rezonanční spektroskopie MeSH
- mastné kyseliny farmakologie MeSH
- molekulární struktura MeSH
- Orthomyxoviridae účinky léků MeSH
- psi MeSH
- silymarin farmakologie MeSH
- viabilita buněk účinky léků MeSH
- zvířata MeSH
- Check Tag
- psi MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
