A5018402712- Silymarin and Mushroom Poisoning
- Synthesis and bioactivity of alkaloids
- Microbial Natural Products and Biosynthesis
- Berberine and alkaloids research
- Carbohydrate Chemistry and Synthesis
- Cholinesterase and Neurodegenerative Diseases
- Chemical Synthesis and Analysis
- Chemical synthesis and alkaloids
- Biochemical and Molecular Research
- Glycosylation and Glycoproteins Research
- Polyamine Metabolism and Applications
- Lysosomal Storage Disorders Research
- Plant biochemistry and biosynthesis
- Synthesis and Biological Activity
- Free Radicals and Antioxidants
- Enzyme function and inhibition
- Synthesis and pharmacology of benzodiazepine derivatives
- Pharmacological Effects of Natural Compounds
- Drug-Induced Hepatotoxicity and Protection
- Enzyme Catalysis and Immobilization
- Marine Toxins and Detection Methods
- Signaling Pathways in Disease
- Plant-based Medicinal Research
- Plant-derived Lignans Synthesis and Bioactivity
- RNA and protein synthesis mechanisms
Czech Academy of Sciences
2010-2024
Czech Academy of Sciences, Institute of Microbiology
2011-2024
Vestas (Denmark)
2018
Charles University
2010-2014
Département de Chimie Moléculaire
2010
Université Joseph Fourier
2010
Centre National de la Recherche Scientifique
2010
Institute of Chemistry of Molecular Recognition
2010
Palacký University Olomouc
2004-2008
University of Mons
2008
Flavonolignans from silymarin, the standardized plant extract obtained thistle, exhibit various antioxidant activities, which correlate with other biological and therapeutic properties of that extract. To highlight mode action flavonolignans as free radical scavengers antioxidants, 10 flavonolignans, selectively methylated at different positions, were tested in vitro for their capacity to scavenge radicals (DPPH superoxide) inhibit lipid peroxidation induced on microsome membranes. The...
Silybin or silibinin, a flavonolignan isolated from Milk thistle seeds, is one of the popular dietary supplements and has been extensively studied for its antioxidant, hepatoprotective anti-cancer properties. We have envisioned that potency silybin could be further enhanced through suitable modification/s in chemical structure. Accordingly, here, we synthesized characterized series derivatives namely 2,3-dehydrosilybin (DHS), 7-O-methylsilybin (7OM), 7-O-galloylsilybin (7OG),...
Quercetin and gallic acid are natural activators of the transcription factor Nrf2, which regulates expression many cytoprotective enzymes including heme oxygenase-1 (HO-1). We developed procedures for synthesis monogalloyl esters quercetin taxifolin (dihydroquercetin), namely, 3-O-galloylquercetin 7-O-galloyltaxifolin, examined their effect on Nrf2 pathway in RAW264.7 cells. Unlike free acid, derivatives isoquercitrin (quercetin-3-O-β-d-glucoside) had no HO-1. In contrast,...
In nature, the flavonolignan silybin (1) occurs as a mixture of two diastereomers, A and B, which in number biological assays exhibit different activities. library hydrolases (lipases, esterases, proteases) was tested for separating B diastereomers by selective transesterification or stereoselective alcoholysis 23-O-acetylsilybin (2). Novozym 435 proved to be most suitable enzyme preparative production both optically pure silybins enzymatic discrimination. Gram amounts substances can...
Abstract This work is a structure‐activity relationship study that investigates the influence of nature and amount negative charge in carbohydrate substrates on affinity β‐ N ‐acetylhexosaminidases, stimulation natural killer cells. It describes synthetic procedures yielding novel glycosides are useful immunoactivation. Specifically, we present thorough ability six C‐6 modified ‐acetylhexosaminides (aldehyde, uronate, 6‐ O ‐sulfate, ‐phosphate) to serve as for cleavage glycosylation by...
Structurally different and functionally diverse natural compounds – antitumour agents pyrrolo[1,4]benzodiazepines, bacterial hormone hormaomycin lincosamide antibiotic lincomycin share a common building unit, 4-alkyl-L-proline derivative (APD). APDs arise from L-tyrosine through special biosynthetic pathway. Its generally accepted scheme, however, did not comply with current state of knowledge. Based on gene inactivation experiments in vitro functional tests recombinant enzymes, we designed...
β-N-Acetylhexosaminidases feature so-called wobbling specificity, which means that they cleave substrates both in gluco- and galacto- configurations, with the activity ratio depending on enzyme source. Here we present new finding fungal β-N-acetylhexosaminidases are able to hydrolyze transfer 4-deoxy-N-acetylhexosaminides high yields. This clearly demonstrates 4-hydroxy moiety at substrate pyranose ring is not essential for binding active site, was also confirmed by molecular docking of...
The synthesis of various silybin monogalloyl esters was developed, and their antiangiogenic activities were evaluated in a variety vitro tests with human umbilical vein endothelial cells (HUVECs). A structure–activity relationship (SAR) study found the regioselectivity galloylation to be highly significant. Silybin (as an equimolar mixture two diastereomers B) exhibited quite poor activities, whereas its B stereoisomer is more active than A. phenolic OH groups natural (a both isomers) leads...
The biosynthetic gene cluster of porothramycin, a sequence-selective DNA alkylating compound, was identified in the genome producing strain Streptomyces albus subsp. (ATCC 39897) and sequentially characterized. A 39.7 kb long region contains 27 putative genes, 18 them revealing high similarity with homologous genes from closely related pyrrolobenzodiazepine (PBD) compound anthramycin. However, considering structures both compounds, number differences composition compared clusters...
The lincomycin biosynthetic gene lmbX was deleted in Streptomyces lincolnensis ATCC 25466, and deletion of this led to abolition production. results complementation experiments proved the blockage biosynthesis precursor 4-propyl-L-proline. Feeding mutant strain with derivatives resulted production 4'-butyl-4'-depropyllincomycin 4'-pentyl-4'-depropyllincomycin high titers without contamination. Moreover, found be more active than against clinical Staphylococcus isolates genes determining...
Two homologous pyridoxal 5′-phosphate-dependent enzymes LmbF and CcbF transform the deacetylated <italic>S</italic>-cysteinyl residue of related intermediates in biosynthesis lincomycin/celesticetin different ways.
Antitumor pyrrolobenzodiazepines (PBDs), lincosamide antibiotics, quorum-sensing molecule hormaomycin, and antimicrobial griselimycin are structurally functionally diverse groups of actinobacterial metabolites. The common feature these compounds is the incorporation l-tyrosine- or l-leucine-derived 4-alkyl-l-proline derivatives (APDs) in their structures. Here, we report that last reaction biosynthetic pathway APDs, catalyzed by F420H2-dependent Apd6 reductases, contributes to structural...