Albendazole (ABZ) is an anthelmintic frequently used to treat haemonchosis, a common parasitosis of ruminants caused by the gastrointestinal nematode Haemonchus contortus. This parasite is able to protect itself against ABZ via the formation of inactive ABZ-glycosides. The present study was designed to deepen the knowledge about the role of UDP-glycosyltransferases (UGTs) in ABZ glycosylation in H. contortus. The induction effect of phenobarbital, a classical inducer of UGTs, as well as ABZ and ABZ-sulphoxide (ABZSO, the main active metabolite of ABZ) on UGTs expression and UGT activity toward ABZ was studied ex vivo in isolated adult nematodes. The effect of three potential UGT inhibitors (5-nitrouracil, 4,6-dihydroxy-5-nitropyrimidine and sulfinpyrazone) on ABZ glycosylation was tested. Pre-incubation of nematodes with ABZ and ABZSO led to increased expression of several UGTs as well as ABZ-glycosides formation in subsequent treatment. Phenobarbital also induced UGTs expression, but did not affect ABZ biotransformation. In the nematode's subcellular fraction, sulfinpyrazone inhibited UGT activity toward ABZ, although no effect of other inhibitors was observed. The inhibitory potential of sulfinpyrazone on the formation of ABZ-glycosides was also proved ex vivo in living nematodes. The obtained results confirmed the role of UGTs in ABZ biotransformation in H. contortus adults and revealed sulfinpyrazone as a potent inhibitor of ABZ glycosylation in this parasite. The possible use of sulfinpyrazone with ABZ in combination therapy merits further research.
- MeSH
- albendazol MeSH
- anthelmintika * terapeutické užití MeSH
- fenobarbital metabolismus farmakologie terapeutické užití MeSH
- glykosidy metabolismus farmakologie terapeutické užití MeSH
- glykosyltransferasy MeSH
- Haemonchus * MeSH
- hlístice * MeSH
- nemoci ovcí * farmakoterapie MeSH
- ovce MeSH
- sulfinpyrazon metabolismus farmakologie terapeutické užití MeSH
- uridindifosfát MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Flavonoids, including anthocyanins, are polyphenolic compounds present in fruits, vegetables and dietary supplements. They can be absorbed from the intestine to the bloodstream or pass into the large intestine. Various bacterial species and enzymes are present along the entire intestine. The aim of the present work was to investigate the intestinal metabolism of selected dietary polyphenol and polyphenol glycosides (quercetin, cyanidin-3-O-glucoside, cyanidin-3-O-galactoside, and delphinidin-3-O-galactoside) by human fecal bacteria. Moreover, the metabolism of metabolites formed from these compounds in human colon carcinoma cells (Caco-2) was also point of the interest. Test compounds were added to fresh human stool in broth or to Caco-2 cells in medium and then incubated for 6 or 20 h at 37°C. After incubation, samples were prepared for LC/MS determination. Main metabolic pathways were deglycosylation, hydrogenation, methylation, hydroxylation, and decomposition. 2,4,5-trihydroxybenzaldehyde, as a metabolite of cyanidin glycosides, was detected after incubation for the first time. Metabolites formed by fecal bacteria were further glucuronidated or methylated by intestinal enzymes. This metabolite profiling of natural compounds has helped to better understand the complex metabolism in the human intestine and this work also has shown the connection of metabolism of natural substances by intestinal bacteria followed by metabolism in intestinal cells.
- MeSH
- Bacteria metabolismus MeSH
- Caco-2 buňky MeSH
- feces mikrobiologie MeSH
- flavonoidy metabolismus MeSH
- glykosidy metabolismus MeSH
- lidé MeSH
- metabolické sítě a dráhy MeSH
- metabolom * MeSH
- nádory tračníku metabolismus MeSH
- polyfenoly metabolismus MeSH
- střevní sliznice metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Fungal β-N-acetylhexosaminidases, though hydrolytic enzymes in vivo, are useful tools in the preparation of oligosaccharides of biological interest. The β-N-acetylhexosaminidase from Talaromyces flavus is remarkable in terms of its synthetic potential, broad substrate specificity, and tolerance to substrate modifications. It can be heterologously produced in Pichia pastoris in a high yield. The mutation of the Tyr470 residue to histidine greatly enhances its transglycosylation capability. The aim of this work was to identify the structural requirements of this model β-N-acetylhexosaminidase for its transglycosylation acceptors and formulate a structure-activity relationship study. Enzymatic reactions were performed using an activated glycosyl donor, 4-nitrophenyl N-acetyl-β-d-glucosaminide or 4-nitrophenyl N-acetyl-β-d-galactosaminide, and a panel of glycosyl acceptors of varying structural features (N-acetylglucosamine, glucose, N-acetylgalactosamine, galactose, N-acetylmuramic acid, and glucuronic acid). The transglycosylation products were isolated and structurally characterized. The C-2 N-acetamido group in the acceptor molecule was found to be essential for recognition by the enzyme. The presence of the C-2 hydroxyl moiety strongly hindered the normal course of transglycosylation, yielding unique non-reducing disaccharides in a low yield. Moreover, whereas the gluco-configuration at C-4 steered the glycosylation into the β(1-4) position, the galacto-acceptor afforded a β(1-6) glycosidic linkage. The Y470H mutant enzyme was tested with acceptors based on β-glycosides of uronic acid and N-acetylmuramic acid. With the latter acceptor, we were able to isolate and characterize one glycosylation product in a low yield. To our knowledge, this is the first example of enzymatic glycosylation of an N-acetylmuramic acid derivative. In order to explain these findings and predict enzyme behavior, a modeling study was accomplished that correlated with the acquired experimental data.
- MeSH
- beta-N-acetylhexosaminidasy chemie metabolismus MeSH
- glykosidy metabolismus MeSH
- glykosylace MeSH
- kinetika MeSH
- konformace proteinů MeSH
- molekulární modely MeSH
- oligosacharidy metabolismus MeSH
- substrátová specifita MeSH
- Talaromyces enzymologie MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Publikační typ
- časopisecké články MeSH
Bacteria represent an underexplored source of diglycosidases. Twenty-five bacterial strains from the genera Actinoplanes, Bacillus, Corynebacterium, Microbacterium, and Streptomyces were selected for their ability to grow in diglycosylated flavonoids-based media. The strains Actinoplanes missouriensis and Actinoplanes liguriae exhibited hesperidin deglycosylation activity (6-O-α-L-rhamnosyl-β-D-glucosidase activity, EC 3.2.1.168), which was 3 to 4 orders of magnitude higher than the corresponding monoglycosidase activities. The diglycosidase production was confirmed in A. missouriensis by zymographic assays and NMR analysis of the released disaccharide, rutinose. The gene encoding the 6-O-α-L-rhamnosyl-β-D-glucosidase was identified in the genome sequence of A. missouriensis 431(T) (GenBank accession number BAL86042.1) and functionally expressed in Escherichia coli. The recombinant protein hydrolyzed hesperidin and hesperidin methylchalcone, but not rutin, which indicates its specificity for 7-O-rutinosylated flavonoids. The protein was classified into the glycoside hydrolase family 55 (GH55) in contrast to the known eukaryotic diglycosidases, which belong to GH1 and GH5. These findings demonstrate that organisms other than plants and filamentous fungi can contribute to an expansion of the diglycosidase toolbox.
- MeSH
- bakteriální proteiny genetika metabolismus MeSH
- beta-glukosidasa genetika metabolismus MeSH
- chalkonoidy chemie metabolismus MeSH
- disacharidy chemie metabolismus MeSH
- Escherichia coli genetika metabolismus MeSH
- exprese genu MeSH
- flavonoidy chemie metabolismus MeSH
- fylogeneze MeSH
- glykosidy chemie metabolismus MeSH
- hesperidin analogy a deriváty chemie metabolismus MeSH
- hydrolýza MeSH
- klonování DNA MeSH
- Micromonosporaceae klasifikace genetika metabolismus MeSH
- rekombinantní proteiny genetika metabolismus MeSH
- rhamnosa chemie metabolismus MeSH
- substrátová specifita MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Preparations with elicitation activity were obtained from the mycelium of Leptosphaeria maculans , a fungal pathogen of oilseed rape (Brassica napus). Crude delipidated and deproteinized extract from fungal cell walls induced expression of pathogenesis related gene 1 (PR1), hydrogen peroxide accumulation, and enhanced resistance of B. napus plants toward infection by L. maculans. Elicitation activity significantly decreased after treatment of a crude extract with α- or β-glucanase. Monosaccharide composition analysis of a crude extract purified by ion-exchange chromatography revealed glucose (∼58 mol %), mannose (∼22 mol %), and galactose (∼18 mol %) as the major sugars. FT-IR and NMR spectra confirmed the presence of both carbohydrate and polypeptide components in the purified product. Correlation NMR experiments defined trisaccharide bound to O-3 of serine residue α-D-Glcp-(1→2)-β-D-Galf-(1→6)-α-D-Manp-(1→3)-L-Ser. Terminal α-D-Glcp and (1→6)-β-D-glucan were also detected. The obtained results strongly support the conclusion that these carbohydrates induce defense response in B. napus plants.
- MeSH
- Ascomycota chemie růst a vývoj imunologie MeSH
- Aspergillus niger enzymologie MeSH
- Brassica napus účinky léků imunologie metabolismus mikrobiologie MeSH
- buněčná stěna chemie MeSH
- buněčné extrakty chemie izolace a purifikace farmakologie MeSH
- chemie zemědělská metody MeSH
- down regulace MeSH
- fungální proteiny analýza chemie metabolismus MeSH
- fungicidy průmyslové chemie izolace a purifikace farmakologie MeSH
- glykosidhydrolasy biosyntéza genetika metabolismus MeSH
- glykosidy analýza chemie metabolismus MeSH
- hydrolýza MeSH
- mycelium chemie růst a vývoj imunologie MeSH
- odolnost vůči nemocem účinky léků MeSH
- oligosacharidy analýza chemie metabolismus MeSH
- peptidové fragmenty analýza chemie metabolismus MeSH
- peroxid vodíku metabolismus MeSH
- rostlinné proteiny biosyntéza genetika metabolismus MeSH
- semenáček účinky léků imunologie metabolismus mikrobiologie MeSH
- upregulace účinky léků MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Klíčová slova
- sladivost stévie (steviosid) 200- 300 x,
- MeSH
- antihypertenziva metabolismus terapeutické užití MeSH
- diterpeny metabolismus terapeutické užití MeSH
- glykosidy metabolismus terapeutické užití MeSH
- hypolipidemika * aplikace a dávkování terapeutické užití MeSH
- klinická studie jako téma využití MeSH
- lidé MeSH
- sladidla * aplikace a dávkování metabolismus terapeutické užití MeSH
- statistika jako téma MeSH
- Stevia * metabolismus růst a vývoj MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
- Geografické názvy
- Asie MeSH
- Japonsko MeSH
A number of biologically active natural products are glycosides. Often, the glycosidic residue is crucial for their activity. In other cases, glycosylation only improves their pharmacokinetic parameters. Enzymatic modification of these glycosides - both extension of the glycoside moiety and its selective trimming - is advantageous due to their selectivity and mildness of the reaction conditions in the presence of reactive and sensitive complex aglycones. Enzymatic reactions enable the resulting products to be used as "natural products", e.g., in nutraceuticals. This chapter concentrates on naturally occurring glycosides used in medicine but also in the food and flavor industry (e.g., sweeteners). Both "classical" and modern methods will be discussed.
Článek podává přehled náhradních sladidlech přírodního původu používaných ve farmacii i běžném životě. Věnuje pozornost novým přírodním nízkoenergetickým sladidlům zejména ze skupiny sacharidů a proteinů.
- Klíčová slova
- thaumatin, monellin, brazzein,
- MeSH
- fruktosa farmakologie metabolismus MeSH
- glykosidy farmakologie klasifikace metabolismus MeSH
- lidé MeSH
- mannitol farmakologie metabolismus MeSH
- monosacharidy farmakologie klasifikace metabolismus MeSH
- oligosacharidy farmakologie klasifikace metabolismus MeSH
- sladidla farmakologie klasifikace metabolismus MeSH
- sorbitol farmakologie metabolismus MeSH
- xylitol farmakologie metabolismus MeSH
- Check Tag
- lidé MeSH
