Modification of the carbohydrate scaffold is an important theme in drug and vaccine discovery. Therefore, the preparation of novel types of glycomimetics is of interest in synthetic carbohydrate chemistry. In this manuscript, we present an early investigation of the synthesis, structure, and conformational behaviour of (1→1)-Si-disaccharides as a novel type of glycomimetics arising from the replacement of interglycosidic oxygen with a dimethyl-, methylpropyl-, or diisopropylsilyl linkage. We accomplished the preparation of this unusual group of umpoled compounds by the reaction of lithiated glycal or 2-oxyglycal units with dialkyldichlorosilanes. We demonstrated the good stability of the "Si-glycosidic" linkage under acidic conditions even at elevated temperatures. Next, we described the conformational landscape of these compounds by the combination of in silico modelling with spectroscopic and crystallographic methods. Finally, we explained the observed conformational flexibility of these compounds by the absence of gauche stabilizing effects that are typically at play in natural carbohydrates.
Study provides an in-depth analysis of the structure-function relationship of polysaccharide anticancer drug carriers and points out benefits and potential drawbacks of differences in polysaccharide glycosidic bonding, branching and drug binding mode of the carriers. Cellulose, dextrin, dextran and hyaluronic acid have been regioselectively oxidized to respective dicarboxylated derivatives, allowing them to directly conjugate cisplatin, while preserving their major structural features intact. The structure of source polysaccharide has crucial impact on conjugation effectiveness, carrier capacity, drug release rates, in vitro cytotoxicity and cellular uptake. For example, while branched structure of dextrin-based carrier partially counter the undesirable initial burst release, it also attenuates the cellular uptake and the cytotoxicity of carried drug. Linear polysaccharides containing β-(1→4) glycosidic bonds and oxidized at C2 and C3 (cellulose and hyaluronate) have the best overall combination of structural features for improved drug delivery applications including potentiation of the cisplatin efficacy towards malignances.
- MeSH
- antitumorózní látky aplikace a dávkování MeSH
- buňky NIH 3T3 MeSH
- celulosa chemie MeSH
- cisplatina aplikace a dávkování MeSH
- dextrany chemie MeSH
- dextriny chemie MeSH
- glykosidy chemie MeSH
- inhibiční koncentrace 50 MeSH
- kyselina hyaluronová chemie MeSH
- kyslík chemie MeSH
- lidé MeSH
- MFC-7 buňky MeSH
- myši MeSH
- nosiče léků * MeSH
- oxidace-redukce MeSH
- platina chemie MeSH
- polysacharidy chemie MeSH
- systémy cílené aplikace léků * MeSH
- techniky in vitro MeSH
- uvolňování léčiv MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
A series of 19 synthetic alkyl and thioalkyl glycosides derived from d-mannose, d-glucose and d-galactose and having C10-C16 aglycone were investigated for cytotoxic activity against 7 human cancer and 2 non-tumor cell lines as well as for antimicrobial potential on 12 bacterial and yeast strains. The most potent compounds were found to be tetradecyl and hexadecyl β-d-galactopyranosides (18, 19), which showed the best cytotoxicity and therapeutic index against CCRF-CEM cancer cell line. Similar cytotoxic activity showed hexadecyl α-d-mannopyranoside (5) but it also inhibited non-tumor cell lines. Because these two galactosides (18, 19) were inactive against all tested bacteria and yeast strains, they could be a target-specific for eukaryotic cells. On the other hand, β-D-glucopyranosides with tetradecyl (11) and hexadecyl (12) aglycone inhibited only Gram-positive bacterial strain Enterococcus faecalis. The studied glycosides induce changes in the lipid bilayer thickness and lateral phase separation at high concentration, as derived from SAXS experiments on POPC model membranes. In general, glucosides and galactosides exhibit more specific properties. Those with longer aglycone show high cytotoxicity and therefore, they are more promising candidates for cancer cell line targeted inhibition.
- MeSH
- antibakteriální látky chemická syntéza chemie farmakologie MeSH
- antitumorózní látky chemická syntéza chemie farmakologie MeSH
- buněčné linie MeSH
- buňky A549 MeSH
- buňky K562 MeSH
- difrakce rentgenového záření MeSH
- Enterococcus faecalis účinky léků MeSH
- galaktosa chemická syntéza chemie farmakologie MeSH
- glykosidy chemická syntéza chemie farmakologie MeSH
- HCT116 buňky MeSH
- lidé MeSH
- lipidové dvojvrstvy chemie MeSH
- maloúhlový rozptyl MeSH
- mikrobiální testy citlivosti MeSH
- molekulární struktura MeSH
- proliferace buněk MeSH
- sacharidové sekvence MeSH
- viabilita buněk účinky léků MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Ca2+/calmodulin-dependent protein kinase kinase 2 (CaMKK2) regulates several key physiological and pathophysiological processes, and its dysregulation has been implicated in obesity, diabetes, and cancer. CaMKK2 is inhibited through phosphorylation in a process involving binding to the scaffolding 14-3-3 protein, which maintains CaMKK2 in the phosphorylation-mediated inhibited state. The previously reported structure of the N-terminal CaMKK2 14-3-3-binding motif bound to 14-3-3 suggested that the interaction between 14-3-3 and CaMKK2 could be stabilized by small-molecule compounds. Thus, we investigated the stabilization of interactions between CaMKK2 and 14-3-3γ by Fusicoccin A and other fusicoccanes-diterpene glycosides that bind at the interface between the 14-3-3 ligand binding groove and the 14-3-3 binding motif of the client protein. Our data reveal that two of five tested fusicoccanes considerably increase the binding of phosphopeptide representing the 14-3-3 binding motif of CaMKK2 to 14-3-3γ. Crystal structures of two ternary complexes suggest that the steric contacts between the C-terminal part of the CaMKK2 14-3-3 binding motif and the adjacent fusicoccane molecule are responsible for differences in stabilization potency between the study compounds. Moreover, our data also show that fusicoccanes enhance the binding affinity of phosphorylated full-length CaMKK2 to 14-3-3γ, which in turn slows down CaMKK2 dephosphorylation, thus keeping this protein in its phosphorylation-mediated inhibited state. Therefore, targeting the fusicoccin binding cavity of 14-3-3 by small-molecule compounds may offer an alternative strategy to suppress CaMKK2 activity by stabilizing its phosphorylation-mediated inhibited state.
- MeSH
- fosforylace účinky léků MeSH
- glykosidy chemie farmakologie MeSH
- kinasa proteinkinasy závislé na vápníku a kalmodulinu chemie metabolismus MeSH
- krystalografie rentgenová MeSH
- lidé MeSH
- mapy interakcí proteinů účinky léků MeSH
- proteiny 14-3-3 chemie metabolismus MeSH
- simulace molekulového dockingu MeSH
- vazba proteinů účinky léků MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
A set of 41 glycosidic conjugates of pentacyclic triterpenes was synthesized in order to improve the solubility of highly cytotoxic parent compounds. Their in vitro cytotoxic activity was evaluated in 25 cancer cell lines and 2 noncancer fibroblasts. Fifteen compounds had high cytotoxicity on the T-lymphoblastic leukemia cell line CCRF-CEM and 6 of them were active in multiple cell lines of various histogenic origin and not toxic in fibroblasts. Compound 11a had IC50 of 0.64 μM in CCRF-CEM cells, 0.60 μM in K-562 cells, and 0.37 μM in PC-3 cells; compound 12a had IC50 of 0.64 μM in CCRF-CEM cells and 0.71 μM in SW620 cells; compound 17b had IC50 of 0.86 μM in HCT116 cells and 0.92 μM in PC-3 cells. Compounds 11b and 12b were slightly less active than the previously mentioned derivatives; however, their solubility was significantly better, and therefore they were selected for the in vivo evaluation of the pharmacokinetic profile in mice. In both compounds, the maximum concentration in plasma was achieved very rapidly-the highest level in plasma was found 1 h after administration (22.2, respectively, 6.4 μM). For compound 12b, the resorption was followed with fast elimination, and 12 h after administration, the compound was not detected in plasma. In contrast, compound 11b was eliminated more slowly; it was still present in plasma after 12 h, but its concentration dropped below the detection limit after 24 h. The elimination half-time determined for compound 11b was 2.4 h and for compound 12b just about 1.4 h. These values are reasonable for further drug development.
- MeSH
- antitumorózní látky chemie farmakologie MeSH
- deoxycukry chemie MeSH
- glykosidy chemie MeSH
- léky antitumorózní - screeningové testy MeSH
- lidé MeSH
- myši MeSH
- nádorové buňky kultivované MeSH
- nádory farmakoterapie metabolismus patologie MeSH
- proliferace buněk * MeSH
- tkáňová distribuce MeSH
- triterpeny chemie farmakokinetika farmakologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Astragalus is a very interesting plant genus, well-known for its content of flavonoids, triterpenes and polysaccharides. Its secondary metabolites are described as biologically active compounds showing several activities, e.g., immunomodulating, antibacterial, antiviral and hepatoprotective. This inspired us to analyze the Bulgarian endemic A. aitosensis (Ivanisch.) to obtain deeper information about its phenolic components. We used extensive chromatographic separation of A. aitosensis extract to obtain seven phenolic compounds (1-7), which were identified using combined LC-MS and NMR spectral studies. The 1D and 2D NMR analyses and HR-MS allowed us to resolve the structures of known compounds 5-7 as isorhamnetin-3-O-robinobioside, isorhamnetin-3-O-(2,6-di-O-α-rhamno-pyranosyl-β-galactopyranoside), and alangiflavoside, respectively, and further comparison of these spectral data with available literature helped us with structural analysis of newly described flavonoid glycosides 1-4. These were described in plant source for the first time.
- MeSH
- Astragalus chemie MeSH
- chromatografie kapalinová MeSH
- fenoly chemie izolace a purifikace MeSH
- flavonoidy chemie izolace a purifikace MeSH
- glykosidy chemie klasifikace izolace a purifikace MeSH
- hmotnostní spektrometrie MeSH
- magnetická rezonanční spektroskopie MeSH
- molekulární struktura MeSH
- triterpeny chemie MeSH
- Publikační typ
- časopisecké články MeSH
Conformational preferences of two C-glycosyl analogues of Manp-(1 → 3)-Manp, were studied using a combined method of theoretical and experimental chemistry. Molecular dynamics was utilized to provide conformational behavior along C-glycosidic bonds of methyl 3-deoxy-3-C-[(α-d-mannopyranosyl)methyl]-α-d- and l-mannopyranosides. The OPLS2005 and Glycam06 force fields were used. Simulations were performed with explicit water (TIP3P) and methanol. Results were compared with a complete conformational scan at the MM4 level with the dielectric constant corresponding to methanol. In order to verify predicted conformational preferences, vicinal 3JHH NMR coupling constants were calculated by the Karplus equation on simulated potential energy surfaces (PES). A set of new parameters for the Karplus equation was also designed. Predicted 3JHH were compared with experimental data. We also used reverse methodology, in which the 3JHH coupling constants were calculated at the DFT level for each family of (ϕ, ψ)-conformers separately and then experimental values were decomposed onto calculated 3JHH couplings in order to obtain experimentally derived populations of conformers. As an alternative method of evaluation of preferred conformers, analysis of sensitive 13C chemical shifts was introduced. We were able to thoroughly discuss several fundamental issues in predictions of preferred conformers of C-saccharides, such as the solvent effect, reliability of the force field, character of empirical Karplus equation or applicability of NMR parameters in predictions of conformational preferences in general.
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
The discovery of effective ligands for DC-SIGN receptor is one of the most challenging concepts of antiviral drug design due to the importance of this C-type lectin in infection processes. DC-SIGN recognizes mannosylated and fucosylated oligosaccharides but glycosidic linkages are accessible to both chemical and enzymatic degradations. To avoid this problem, the synthesis of stable glycoside mimetics has attracted increasing attention. In this work we establish for the first time mono- and divalent C-glycosides based on d-manno and l-fuco configurations as prospective DC-SIGN ligands. In particular, the l-fucose glycomimetics were more active than the respective d-mannose ones. The highest affinity was assessed for simple 1,4-bis(α-l-fucopyranosyl)butane (SPR: IC50 0.43 mM) that displayed about twice higher activity than natural ligand Le(x). Our results make C-glycosides attractive candidates for multivalent presentations.
- MeSH
- biomimetika MeSH
- fukosa chemie MeSH
- glykosidy chemická syntéza chemie MeSH
- lektiny typu C chemie metabolismus MeSH
- lidé MeSH
- mannosa chemie MeSH
- molekulární struktura MeSH
- molekuly buněčné adheze chemie metabolismus MeSH
- receptory buněčného povrchu chemie metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články 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
