Geschmack ist vorhersagbar: Mit FlavorMiner. FlavorMiner heißt das Tool, das IPB-Chemiker und Partner aus Kolumbien jüngst entwickelt haben. Das Programm kann, basierend auf maschinellem Lernen (KI), anhand der…
Seit Februar 2021 bietet Wolfgang Brandt, ehemaliger Leiter der Arbeitsgruppe Computerchemie am IPB, sein Citizen Science-Projekt zur Pilzbestimmung an. Dafür hat er in regelmäßigen Abständen öffentliche Vorträge zur Vielfalt…
Fobofou, S. A. T.; Franke, K.; Brandt, W.; Manzin, A.; Madeddu, S.; Serreli, G.; Sanna, G.; Wessjohann, L. A.;Bichromonol, a dimeric coumarin with anti-HIV activity from the stem bark of Hypericum roeperianumNat. Prod. Res.371947-1953(2023)DOI: 10.1080/14786419.2022.2110094
Infectious diseases caused by viruses like HIV and SARS-COV-2 (COVID-19) pose serious public health threats. In search for new antiviral small molecules from chemically underexplored Hypericum species, a previously undescribed atropisomeric C8-C8’ linked dimeric coumarin named bichromonol (1) was isolated from the stem bark of Hypericum roeperianum. The structure was elucidated by MS data and NMR spectroscopy. The absolute configuration at the biaryl axis was determined by comparing the experimental ECD spectrum with those calculated for the respective atropisomers. Bichromonol was tested in cell-based assays for cytotoxicity against MT-4 (CC50 ¼ 54 mM) cells and anti-HIV activity in infected MT-4 cells. It exhibits significant activity at EC50 ¼ 6.6–12.0 mM against HIV-1 wild type and its clinically relevant mutant strains. Especially, against the resistant variants A17 and EFVR, bichromonol is more effective than the commercial drug nevirapine and might thus have potential to serve as a new anti-HIV lead.
Publikation
Agzamova, M. A.; Mamadalieva, N. Z.; Mamadalieva, N.; Porzel, A.; Hussain, H.; Dube, M.; Franke, K.; Janibekov, A.; Wessjohann, L. A.;Lehmanniaside, a new cycloartane triterpene glycoside from Astragalus lehmannianusNat. Prod. Res.37354-359(2023)DOI: 10.1080/14786419.2021.1969563
Chemical investigation of the aerial parts of Astragalus lehmannianus
Bunge (Leguminosae) led to the isolation and identification of a new
cycloartane triterpene glycoside – lehmanniaside (2\'-O-acetyl-3-β-O-D-xylopyranosyl-3β,6α,16β,24α-tetrahydroxy-20,25-epoxycycloartane).
Its structure was elucidated by means of spectroscopic analysis (HR-MS,
1D and 2D NMR). Bioassays showed that lehmanniaside exhibits weak
anthelmintic, antifungal, and cytotoxic activities.
Publikation
Humpierre, A. R.; Zanuy, A.; Saenz, M.; Vasco, A. V.; Méndez, Y.; Westermann, B.; Cardoso, F.; Quintero, L.; Santana, D.; Verez, V.; Valdés, Y.; Rivera, D. G.; Garrido, R.;Quantitative NMR for the structural analysis of novel bivalent glycoconjugates as vaccine candidatesJ. Pharm. Biomed. Anal.214114721(2022)DOI: 10.1016/j.jpba.2022.114721
Novel unimolecular bivalent glycoconjugates were assembled combining several functionalized capsular polysaccharides of Streptococcus pneumoniae and Neisseria meningitidis to a carrier protein by using an effective strategy based on the Ugi 4-component reaction. The development of multivalent glycoconjugates opens new opportunities in the field of vaccine design, but their high structural complexity involves new analytical challenges. Nuclear Magnetic Resonance has found wide applications in the characterization and impurity profiling of carbohydrate-based vaccines. Eight bivalent conjugates were studied by quantitative NMR analyzing the structural identity, the content of each capsular polysaccharide, the ratios between polysaccharides, the polysaccharide to protein ratios and undesirable contaminants. The qNMR technique involves experiments with several modified parameters for obtaining spectra with quantifiable signals. In addition, the achieved NMR results were combined with the results of colorimetric assay and Size Exclusion HPLC for assessing the protein content and free protein percentage, respectively. The application of quantitative NMR showed to be efficient to clear up the new structural complexities while allowing the quantitative assessment of the components.
Publikation
Nugraha, A. S.; Untari, L. F.; Laub, A.; Porzel, A.; Franke, K.; Wessjohann, L. A.;Anthelmintic and antimicrobial activities of three new depsides and ten known depsides and phenols from Indonesian lichen: Parmelia cetrata Ach.Nat. Prod. Res.355001-5010(2021)DOI: 10.1080/14786419.2020.1761361
An extensive phytochemical study of a foliose lichen from Indonesia, Parmelia cetrata, resulted in the successful isolation of 13 phenol and depside derivatives (1–13) including the previously unreported depsides 3′-hydroxyl-5′-pentylphenyl 2,4-dihydroxyl-6-methylbenzoate (7), 3′-hydroxyl-5′-propylphenyl 2,4-dihydroxyl-6-methylbenzoate (8) and 3′-hydroxyl-5′-methylphenyl 2-hydroxyl-4-methoxyl-6-propylbenzoate (9). The anti-infective activity of isolated compounds was evaluated against the gram-negative bacterium Aliivibrio fischeri and the nematode Caenorhabditis elegans. 2,4-Dihydroxyl-6-pentylbenzoate (5) and lecanoric acid (6) induced growth inhibition of A. fischeri with inhibition values of 49% and 100% at a concentration of 100 µM, respectively. The antibacterial activity might be due to their free carboxyl group. A phenolic group at C4 also contributed to the antimicrobial activity of the depsides as shown for compounds 7 and 8, which caused 89% and 96% growth inhibition at 100 µM, respectively. Lecanoric acid (6) in addition possesses significant anthelmintic effects causing 80% mortality of C. elegans at 100 µg/mL.