jump to searchjump to navigationjump to content

Publications - Bioorganic Chemistry

Sort by: Year Type of publication

Displaying results 701 to 710 of 1151.

Publications

Barreto, A. d. F. S.; Vercillo, O. E.; Birkett, M. A.; Caulfield, J. C.; Wessjohann, L. A.; Andrade, C. K. Z.; Fast and efficient microwave-assisted synthesis of functionalized peptoids via Ugi reactions Org. Biomol. Chem. 9, 5024-5027, (2011) DOI: 10.1039/C1OB05471F

A wide range of N-alkylglycines (peptoids) can be efficiently prepared viaUgi reactions using microwave irradiations. The results confirm the versatility and efficiency of the methodology for the preparation of functionalized peptoids. The products can be used in consecutive Ugi reactions to yield cyclic peptoids of potential biological interest.
Publications

Bakthir, H.; Awadh Ali, N. A.; Arnold, N.; Teichert, A.; Wessjohann, L.; Anticholinesterase activity of endemic plant extracts from Soqotra Afr. J. Tradit. Complement. Altern. Med. 8, 296-299, (2011) DOI: 10.4314/ajtcam.v8i3.65292

A total of 30 chloroform and methanol extracts from the following endemic Soqotran plants Acridocarpus socotranus Olive, Boswellia socotranao Balf.fil, Boswellia elongata Balf. fil., Caralluma socotrana N. Br, Cephalocroton socotranus Balf.f, Croton socotranus Balf. fil.., Dendrosicycos socotrana Balf.f., Dorstenia gigas Schweinf. ex Balf. fil., Eureiandra balfourii Cogn. & Balf. fil., Kalanchoe farinaceae Balf.f, Limonium sokotranum (Vierh) Radcl. Sm), Oldenlandia pulvinata, Pulicaria diversifolia( Balf. and Pulicaria stephanocarpa Balf. were screened for their acetylcholinesterase inhibitory activity by using in vitro Ellman method at 50 and 200 μg/ml concentrations. Chloroform extracts of Croton socotranus, Boswellia socotrana, Dorstenia gigas, and Pulicaria stephanocarpa as well as methanol extracts of Eureiandra balfourii exhibited inhibitory activities higher than 50 % at concentration of 200 μg. At a concentrations of 50 μg, the chloroform extract of Croton socotranus exhibited an inhibition of 40.6 %.
Publications

Mansfeld, J.; Brandt, W.; Haftendorn, R.; Schöps, R.; Ulbrich-Hofmann, R.; Discrimination between the regioisomeric 1,2- and 1,3-diacylglycerophosphocholines by phospholipases Chem. Phys. Lipids 164, 196-204, (2011) DOI: 10.1016/j.chemphyslip.2010.12.009

The artificial 1,3-diacyl-glycero-2-phosphocholines (1,3-PCs), which form similar aggregate structures as the naturally occurring 1,2-diacyl-sn-glycero-3-phosphocholines (1,2-PCs), were tested as substrates for different classes of phospholipases such as phospholipase A2 (PLA2) from porcine pancreas, bee and snake venom, and Arabidopsis thaliana, phospholipase C (PLC) from Bacillus cereus, and phospholipase D (PLD) from cabbage and Streptomyces species. The regioisomers of the natural phospholipids were shown to bind to all investigated phospholipases with an affinity similar to the corresponding naturally occurring phospholipids, however their hydrolysis was reduced to different degrees (PLA2s and PLC) or even abolished (PLDs belonging to the PLD superfamily). The results are in accordance with binding models obtained by docking the substrates to the crystal structures or homology models of the phospholipases.
Publications

Lee, D.-U.; Park, J. H.; Wessjohann, L.; Schmidt, J.; Alkaloids from Papaver coreanum Nat. Prod. Commun. 6, 1593-1594, (2011) DOI: 10.1177/1934578X1100601109

The alkaloid pattern of the endemic plant Papaver coreanum Nakai (Papaveraceae) was determined for the first time. Eight alkaloids could be identified by LC/ESIMS/MS and high-resolution mass spectrometry. Among them, protopine and allocryptopine represent the main components. Besides norsanguinarine, sanguinarine, dihydrosanguinarine, oxysanguinarine, lincangenine, and cryptopine, some other trace alkaloids were found whose structures remain unknown.
Publications

Kopycki, J.; Schmidt, J.; Abel, S.; Grubb, C. D.; Chemoenzymatic synthesis of diverse thiohydroximates from glucosinolate-utilizing enzymes from Helix pomatia and Caldicellulosiruptor saccharolyticus Biotechnol. Lett. 33, 1039-1046, (2011) DOI: 10.1007/s10529-011-0530-y

Thiohydroximates comprise a diverse class of compounds important in both biological and industrial chemistry. Their syntheses are generally limited to simple alkyl and aryl compounds with few stereocenters and a narrow range of functional groups. We hypothesized that sequential action of two recombinant enzymes, a sulfatase from Helix pomatia and a β-O-glucosidase from Caldicellulosiruptor saccharolyticus, on glucosinolates would allow synthesis of thiohydroximates from a structurally broad array of abundant precursors. We report successful synthesis of thiohydroximates of varied chemical classes, including from homochiral compounds of demonstrated biological activity. The chemoenzymatic synthetic route reported here should allow access to many, if not all, of the thiohydroximate core structures of the ~200 known naturally occurring glucosinolates. The enrichment of this group for compounds with possible pharmacological potential is discussed.
Publications

Heinke, R.; Franke, K.; Porzel, A.; Wessjohann, L. A.; Awadh Ali, N. A.; Schmidt, J.; Furanocoumarins from Dorstenia foetida Phytochemistry 72, 929-934, (2011) DOI: 10.1016/j.phytochem.2011.03.008

The linear furanocoumarins 5-(2,3-epoxy-3-methyl-butoxy)-chalepensin, 5-methoxy-3-(3-methyl-2,3-dihydroxybutyl)-psoralen-diacetate (7), 5-methoxy-3-[3-(β-d-glucopyranosyloxy)-2-acetyloxy-3-methyl-butyl]-psoralen and 5-(3-methyl-2,3-dihydroxybutyloxy)-3-[3-(β-d-glucopyranosyloxy)-2-hydroxy-3-methyl-butyl]-psoralen, and the coumarin derivative 7-hydroxy-5-methoxy-6-carboxymethyl-3-[3-(β-d-glucopyranosyloxy)-2-hydroxy-3-methyl-butyl]-coumarin were isolated from the leaves of Dorstenia foetida (Moraceae) along with the known compounds psoralen, bergapten, isopimpinellin, phellopterin, 5-methoxychalepensin and turbinatocoumarin. Further furanocoumarins were characterized by ESI-MS/MS investigations. The nonpolar extracts of D. foetida exhibit antifungal, antibacterial and cytotoxic activity, however, no anthelminthic activity.
Books and chapters

Wessjohann, L. A.; Ostrowski, S.; Bakulev, V.; Berseneva, V.; Bogdanov, A. V.; Romanova, I. P.; Mironov, V. F.; Larionova, O. A.; Shaikhutdinova, G. R.; Sinyashin, O. G.; Baibulatova, N. Z.; Dokichev, V. A.; Fedorova, O. V.; Ovchinnikova, I. G.; Rusinov, G. L.; Titova, J. A.; Nasonova, A.; Kim, D.-J.; Kim, K.-S.; Jang, Y. M.; Kim, S. J.; Rakhimova, E. B.; Minnebaev, A. B.; Akhmetova, V. R.; Qin, C.; Zhang, R.; Wang, Q.; Ren, J.; Tian, L.; Mironov, M. A.; Demina, T. S.; Tcoy, A. M.; Akopova, T. A.; Markvicheva, E. A.; Chernyshenko, A. O.; Zelenetski, A. N.; Pandit, S. S.; Multi-Component Reactions in Supramolecular Chemistry and Material Science (Mironov, M. A., ed.). Adv. Exp. Med. Biol. 699, 173-201, (2011) ISBN: 978-1-4419-7270-5 DOI: 10.1007/978-1-4419-7270-5_6

Multi-component reactions of building blocks with more than one MCR-reactive group will give rise to oligomeric MCR products. The proper choice of at least two bifunctional building blocks will give either a polymeric or a cyclic product. Apart from polymerization, repetitive or consecutive Ugi reactions have been used to produce linear MCR-heterooligomers with such building blocks.
Books and chapters

Wessjohann, L. A.; Nin Brauer, M. C.; Brand, K.; Chalcogen-Based Organocatalysis (Mahrwald, R., ed.). 209-314, (2011) ISBN: 978-90-481-3865-4 DOI: 10.1007/978-90-481-3865-4_7

Most current organocatalysts are based on nitrogen (or phosphorus) as reactive atom, including also most processes depending on proton acidity and/or Lewis basicity. Only few organocatalytic systems use organochalcogens, although such reactions are of great importance in nature, especially evident in hydrolases with serine or cysteine as catalytic hotspot, or in oxidoreductases with cysteine or selenocysteine as key players. Catalytic processes in nature commonly rely on the nucleophilic or redox properties of chalcogen atoms. Accordingly early attempts in chemical catalysis using organochalcogens concentrate either on systems reminiscent of catalytic diads and triads of enzymes with catalysts consisting of a hydroxyl or sulfhydryl group that is activated as nucleophile by a neighboring base (catalytic diads and triads). Other “traditional” uses of chalcogen-based catalysts comprise chiral dioxiranes and oxaziranes for epoxidations, and sulfur redox catalysts, the latter especially in the application of sulfur ylides covered by the predominant work of Aggarwal et al. Since the advent of “Organocatalysis” as a distinct subfield of catalysis, not only these traditional organochalcogen catalyst systems excelled; also new applications are more systematically studied now, including not only oxygen and sulfur but increasingly selenium – and to a smaller extent – even tellurium based catalysis [372]. If nature and its several thousand years of selection of catalysis modes serve as a reference, group VI-based catalysis is yet very much below its real potential in chemical organocatalysis. This contribution thus aims at giving the reader an entry into this so much underutilized field, which offers ample room especially for those who like to try new paths and who not only wish expand on existing processes of well ­established nitrogen-based catalysts.
Publications

Henze, M.; Kreye, O.; Brauch, S.; Nitsche, C.; Naumann, K.; Wessjohann, L. A.; Westermann, B.; Photoaffinity-Labeled Peptoids and Depsipeptides by Multicomponent Reactions Synthesis 2010, 2997-3003, (2010) DOI: 10.1055/s-0030-1258182

Photoaffinity tags can be incorporated easily into peptoids and congeners by the Ugi and Passerini multicomponent reactions. Products related to photo-methionine and photo-leucine can be accomplished by diazirine-containing building blocks. The same protocols can be used to synthesize derivatives with benzophenone photo cross-linkers.
Publications

Haack, M.; Löwinger, M.; Lippmann, D.; Kipp, A.; Pagnotta, E.; Iori, R.; Monien, B. H.; Glatt, H.; Brauer, M. N.; Wessjohann, L. A.; Brigelius-Flohé, R.; Breakdown products of neoglucobrassicin inhibit activation of Nrf2 target genes mediated by myrosinase-derived glucoraphanin hydrolysis products Biol. Chem. 391, 1281-1293, (2010) DOI: 10.1515/bc.2010.134

Glucosinolates (GLSs) present in Brassica vegetables serve as precursors for biologically active metabolites, which are released by myrosinase and induce phase 2 enzymes via the activation of Nrf2. Thus, GLSs are generally considered beneficial. The pattern of GLSs in plants is various, and contents of individual GLSs change with growth phase and culture conditions. Whereas some GLSs, for example, glucoraphanin (GRA), the precursor of sulforaphane (SFN), are intensively studied, functions of others such as the indole GLS neoglucobrassicin (nGBS) are rather unknown as are functions of combinations thereof. We therefore investigated myrosinase-treated GRA, nGBS and synthetic SFN for their ability to induce NAD(P)H:quinone oxidoreductase 1 (NQO1) as typical phase 2 enzyme, and glutathione peroxidase 2 (GPx2) as novel Nrf2 target in HepG2 cells. Breakdown products of nGBS potently inhibit both GRA-mediated stimulation of NQO1 enzyme and Gpx2 promoter activity. Inhibition of promoter activity depends on the presence of an intact xenobiotic responsive element (XRE) and is also observed with benzo[a]pyrene, a typical ligand of the aryl hydrocarbon receptor (AhR), suggesting that suppressive effects of nGBS are mediated via AhR/XRE pathway. Thus, the AhR/XRE pathway can negatively interfere with the Nrf2/ARE pathway which has consequences for dietary recommendations and, therefore, needs further investigation.
  • Die Leibniz-Gemeinschaft
  • Digitalization in agriculture
  • Universität Halle
IPB Mainnav Search