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Publikationen - Natur- und Wirkstoffchemie

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Publikation

Reisberg, M., Arnold, N., Porzel, A., Neubert Reinhard, H. H. & Dräger, B. Malusides, novel glucosylceramides isolated from apple pomace (Malus domestica). Z NATURFORSCH C 73, 33-39, (2018) DOI: org.10.1515/znc-2017-0059

Three new glucosylceramides (GluCers) named malusides I–III (1–3) were isolated from apple (cultivars of Malus domestica) pomace (fruit material remaining after juice extraction). An unusual oxo/hydroxy group pattern within the sphingadienine (d18:2) type sphingoid base was observed. All compounds contained the same α-hydroxylated fatty acid (h16:0) and a β-D-glucose moiety. Their structures were assigned on the basis of one- and two-dimensional (1D and 2D) nuclear magnetic resonance (NMR) spectroscopic analyses and mass spectrometry (MS) measurements.
Publikation

Schober, D., Jacob, D., Wilson, M., Cruz, J. A., Marcu, A., Grant, J. R., Moing, A., Deborde, C., de Figueiredo, L. F., Haug, K., Rocca-Serra, P., Easton, J., Ebbels, T. M. D., Hao, J., Ludwig, C., Günther, U. L., Rosato, A., Klein, M. S., Lewis, I. A., Luchinat, C., Jones, A. R., Grauslys, A., Larralde, M., Yokochi, M., Kobayashi, N., Porzel, A., Griffin, J. L., Viant, M. R., Wishart, D. S., Steinbeck, C., Salek, R. M. & Neumann, S. nmrML: A community supported open data standard for the description, storage, and exchange of NMR data. Anal Chem. 90 , 649–656, (2018) DOI: 10.1021/acs.analchem.7b02795

NMR is a widely used analytical technique with a growing number of repositories available. As a result, demands for a vendor-agnostic, open data format for long-term archiving of NMR data have emerged with the aim to ease and encourage sharing, comparison, and reuse of NMR data. Here we present nmrML, an open XML-based exchange and storage format for NMR spectral data. The nmrML format is intended to be fully compatible with existing NMR data for chemical, biochemical, and metabolomics experiments. nmrML can capture raw NMR data, spectral data acquisition parameters, and where available spectral metadata, such as chemical structures associated with spectral assignments. The nmrML format is compatible with pure-compound NMR data for reference spectral libraries as well as NMR data from complex biomixtures, i.e., metabolomics experiments. To facilitate format conversions, we provide nmrML converters for Bruker, JEOL and Agilent/Varian vendor formats. In addition, easy-to-use Web-based spectral viewing, processing, and spectral assignment tools that read and write nmrML have been developed. Software libraries and Web services for data validation are available for tool developers and end-users. The nmrML format has already been adopted for capturing and disseminating NMR data for small molecules by several open source data processing tools and metabolomics reference spectral libraries, e.g., serving as storage format for the MetaboLights data repository. The nmrML open access data standard has been endorsed by the Metabolomics Standards Initiative (MSI), and we here encourage user participation and feedback to increase usability and make it a successful standard.
Bücher und Buchkapitel

Chini, A., Monte, I., Zamarreño, A. M., Hamberg, M., Lassueur, S., Reymond, P., Weiss, S., Stintzi, A., Schaller, A., Porzel, A., García-Mina, J. M. & Solano, R. An OPR3-independent pathway uses 4,5-didehydrojasmonate for jasmonate synthesis. Nat Chem Biol 14, 171-178, (2018) DOI: 10.1038/nchembio.2540

Biosynthesis of the phytohormone jasmonoyl-isoleucine (JA-Ile) requires reduction of the JA precursor 12-oxo-phytodienoic acid (OPDA) by OPDA reductase 3 (OPR3). Previous analyses of the opr3-1 Arabidopsis mutant suggested an OPDA signaling role independent of JA-Ile and its receptor COI1; however, this hypothesis has been challenged because opr3-1 is a conditional allele not completely impaired in JA-Ile biosynthesis. To clarify the role of OPR3 and OPDA in JA-independent defenses, we isolated and characterized a loss-of-function opr3-3 allele. Strikingly, opr3-3 plants remained resistant to necrotrophic pathogens and insect feeding, and activated COI1-dependent JA-mediated gene expression. Analysis of OPDA derivatives identified 4,5-didehydro-JA in wounded wild-type and opr3-3 plants. OPR2 was found to reduce 4,5-didehydro-JA to JA, explaining the accumulation of JA-Ile and activation of JA-Ile-responses in opr3-3 mutants. Our results demonstrate that in the absence of OPR3, OPDA enters the β-oxidation pathway to produce 4,5-ddh-JA as a direct precursor of JA and JA-Ile, thus identifying an OPR3-independent pathway for JA biosynthesis.

Publikation

Edeler, D., Arlt, S., Petković, V., Ludwig, G., Drača, D., Maksimović-Ivanić, D., Mijatović, S. & Kaluđerović, G. N. Delivery of [Ru(η6-p-cymene)Cl2{Ph2P(CH2)3SPh-κP}] using unfunctionalized and mercapto functionalized SBA-15 mesoporous silica: Preparation, characterization and in vitro study. J Inorg Biochem. 180, 155-162, (2018) DOI: 10.1016/j.jinorgbio.2017.12.011

SBA-15 (Santa Barbara Amorphous 15) mesoporous silica and its functionalized form (with 3-mercaptopropyltriethoxysilane) SBA-15~SH were used as carriers for [Ru(η6-p-cymene)Cl2{Ph2P(CH2)3SPh-κP}] complex, denoted as [Ru]. Prepared mesoporous silica nanomaterials were characterized by traditional methods. Materials without [Ru] complex did not show any cytotoxic activity against melanoma B16 and B16-F10 cell lines. On the contrary, materials containing [Ru] such as SBA-15¦[Ru] and SBA-15~SH¦[Ru], exhibited very high activity against tested tumor cell lines, moreover with similar inhibitory potential. According to the loaded amount of the [Ru] in SBA-15¦[Ru] and SBA-15~SH¦[Ru] the IC50 values are 1–2 μM depending on the test used, thus in comparison to [Ru] alone the activity of nanomaterials containing [Ru] are elevated 3–6 times in vitro. However, the mechanism of apoptosis induction differs for these two mesoporous silica. Unlike reference [Ru] compound and SBA-15~SH¦[Ru], SBA-15¦[Ru] induces high caspase activation. Discrepancy in mechanism of drugs action at intracellular level points towards an influence of functionalization as well as availability of the drug. Moreover, both SBA-15¦[Ru] and SBA-15~SH¦[Ru] similarly to [Ru] are declining autophagy in B16 cell line.
Publikation

Mot, A. C., Prell, E., Klecker, M., Naumann, C., Faden, F., Westermann, B. & Dissmeyer, N. Real-time detection of PROTEOLYSIS1 (PRT1)-mediated ubiquitination via fluorescently labeled substrate probes New Phytolog 217 , 613-624, (2018) DOI: 10.1111/nph.14497

The N-end rule pathway has emerged as a major system for regulating protein functions by controlling their turnover in medical, animal and plant sciences as well as agriculture. Although novel functions and enzymes of the pathway have been discovered, the ubiquitination mechanism and substrate specificity of N-end rule pathway E3 ubiquitin ligases have remained elusive. Taking the first discovered bona fide plant N-end rule E3 ligase PROTEOLYSIS1 (PRT1) as a model, we used a novel tool to molecularly characterize polyubiquitination live, in real time.
We gained mechanistic insights into PRT1 substrate preference and activation by monitoring live ubiquitination using a fluorescent chemical probe coupled to artificial substrate reporters. Ubiquitination was measured by rapid in-gel fluorescence scanning as well as in real time by fluorescence polarization.
The enzymatic activity, substrate specificity, mechanisms and reaction optimization of PRT1-mediated ubiquitination were investigated ad hoc instantaneously and with significantly reduced reagent consumption.
We demonstrated that PRT1 is indeed an E3 ligase, which has been hypothesized for over two decades. These results demonstrate that PRT1 has the potential to be involved in polyubiquitination of various substrates and therefore pave the way to understanding recently discovered phenotypes of prt1 mutants.
Publikation

Otto, A., Porzel, A., Westermann, B., Brandt, W., Wessjohann, L. & Arnold, N. Structural and stereochemical elucidation of new hygrophorones from Hygrophorus abieticola (Basidiomycetes) Tetrahedron 73, 1682-1690, (2017) DOI: http://dx.doi.org/10.1016/j.tet.2017.02.013

Four new hygrophorones (1–4) together with the known hygrophorone B12 (5) have been isolated from fruiting bodies of the basidiomycete Hygrophorus abieticola Krieglst. ex Gröger & Bresinsky. Their structures were assigned on the basis of extensive one and two dimensional NMR spectroscopic analyses as well as ESI-HRMS measurements. Among these compounds, two previously undescribed hygrophorone types, named hygrophorone H12 (3) and 2,3-dihydrohygrophorone H12 (4), were identified. The absolute configuration of hygrophorone E12 (2) is suggested based on quantum chemical CD calculations, while a semisynthetic approach in conjunction with computational studies and analysis of NOE interactions allowed the stereochemical assignment of compounds 3 and 4. Additionally, semisynthetic derivatives of hygrophorone B12 (5) were generated by acetylation of the hydroxyl groups. The biological activity of the natural and semisynthetic hygrophorones was evaluated against phytopathogenic organisms, revealing that the α,β-unsaturated carbonyl functionality is likely to be an essential structural feature. Hygrophorone B12 (5) was identified as the most active compound, acting against both ascomycetous fungi and oomycetes.

Publikation

Kaluđerović, N. G., Bulatović, M., Krajnović, T., Paschke, R., B. Zmejkovski, B., Maksimović-Ivanić, D. & Mijatović, S. (18-Crown-6)potassium(I) Trichlorido[28-acetyl-3-(tris-(hydroxylmethyl)amino-ethane)betulinic ester-κN]platinum(II): synthesis and in vitro antitumor activity. Inorganics 5, 56, (2017) DOI: 10.3390/inorganics5030056

Synthesis of platinum(II) conjugate with acetylated betulinic acid tris(hydroxymethyl)aminomethane ester (BATRIS) is presented (BATRISPt). HR-ESI-MS and multinuclear NMR spectroscopy, as well as elemental analysis were used for characterization of BATRISPt. Cytotoxicity (3-(4,5-dimethythiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), crystal violet (CV), and sulforhodamine B (SRB) assays) of BA, BATRIS, BATRISPt, and cisplatin were assessed on seven different tumor cell lines: melanoma B16, colon HCT116 and DLD-1, adenocarcinoma HeLa, breast MCF-7, and anaplastic thyroid tumor 8505C and SW1736; as well as normal MRC-5 fibroblasts. Furthermore, the effect of the mentioned compounds on the apoptosis (Annexin V/PI assay) and autophagy induction (acridine orange (AO) assay) as well as caspase 3, 8, and 9 activation were investigated on the selected B16 melanoma cell line. BATRISPt showed lower activity than BA, BATRIS, or cisplatin. All tested compounds triggered apoptosis in B16 cells. Induction of autophagy was observed in B16 cells exposed only to BATRIS. On the other hand, new conjugate activates caspases 8 and 9 in B16 cells with higher impact than BATRIS or cisplatin alone.
Bücher und Buchkapitel

Wessjohann, L. A., Kreye, O. & Rivera, D. G. One-Pot assembly of amino acid bridged hybrid macromulticyclic cages through multiple multicomponent macrocyclizations. Angew Chem Int Ed. = Angew Chem. 56 = 129 , 3501-3505 = 3555-3559., (2017) DOI: 10.1002/anie.201610801

An important development in the field of macrocyclization strategies towards molecular cages is described. The approach comprises the utilization of a double Ugi four-component macrocyclization for the assembly of macromulticycles with up to four different tethers, that is, hybrid cages. The innovation of this method rests on setting up the macromulticycle connectivities not through the tethers but through the bridgeheads, which in this case involve N-substituted amino acids. Both dilution and metal-template-driven macrocyclization conditions were implemented with success, enabling the one-pot formation of cryptands and cages including steroidal, polyether, heterocyclic, peptidic, and aryl tethers. This method demonstrates substantial complexity-generating character and is suitable for applications in molecular recognition and catalysis.
Publikation

Ristok, C., Leppert, K. N., Franke, K., Scherer-Lorenzen, M., Niklaus, P. A., Wessjohann, L. A. & Bruelheide, H. Leaf litter diversity positively affects the decomposition of plant polyphenols. Plant Soil 419, 305–317, (2017) DOI: 10.1007/s11104-017-3340-8

Background and Aims
Leaf litter decomposition is closely linked to nutrient cycling and driven by environmental conditions, species-specific leaf chemistry, and here in particular by polyphenols composition. However, not much attention has been paid on the decomposition of polyphenols themselves. We hypothesized that phenolics and tannin decomposition rates are species-specific and positively affected by litter species richness.

Methods
Leaf litter of three Chinese tree species was exposed to field decomposition conditions, aggregated in mixtures of different species richness (1-, 2-, 3-species mixtures). We sampled litter five times over the course of 171 days, calculated species-specific total phenolics and total protein precipitable tannin decomposition rates, assessed changes in polyphenol composition using HPLC, and tentatively identified compounds by LC-ESI-MS/MS.

Results
Leaf litter richness effects on phenolics and tannin decomposition rates were positive, except for Sapindus-specific tannins, and differed between leaf litter species. Decomposition duration changed polyphenol compositions, and significantly interacted with leaf litter species richness with increasing effects of litter richness with time.

Conclusions
Litter diversity effects on polyphenol decomposition are crucial for whole leaf litter decomposition. The contrasting dependencies of phenolics and tannin decomposition rates on leaf litter richness may provide explanations for equivocal results in leaf litter mixture experiments.
Publikation

Ali, N A. A., Chhetri, B. K., Dosoky, N. S., Shari, K., Al-Fahad, A. J. A., Wessjohann, L. & Setzer, W. N. Antimicrobial, antioxidant, and cytotoxic activities of Ocimum forskolei and Teucrium yemense (Lamiaceae) essential oils. Medicines 4(2), 17, (2017) DOI: 10.3390/medicines4020017

Background: Ocimum forskolei and Teucrium yemense (Lamiaceae) are used in traditional medicine in Yemen. Methods: The chemical composition, antimicrobial, antioxidant and cytotoxic activities of the essential oils isolated from the leaves of Ocimum forskolei Benth. (EOOF) and two different populations of Teucrium yemense Deflers., one collected from Dhamar province (EOTY-d), and another collected from Taiz (EOTY-t) were investigated. The antimicrobial activities of the oils were evaluated against several microorganisms with the disc diffusion test or the broth microdilution test. The essential oils were screened for in-vitro cytotoxic activity against human tumor cells. EOOF and EOTY-d were screened for free-radical-inhibitory activity using the DPPH radical scavenging assay. Results: Sixty-four compounds were identified in (EOOF) representing 100% of the oil content with endo-fenchol (31.1%), fenchone (12.2%), τ-cadinol (12.2%), and methyl (E)-cinnamate (5.1%) as the major compounds. In EOTY-d, 67 compounds were identified, which made up 91% of the total oil. The most abundant constituents were (E)-caryophyllene (11.2%), α-humulene (4.0.%), γ-selinene (5.5%), 7-epi-α-selinene (20.1%), and caryophyllene oxide (20.1%), while the major compounds in EOTY-t were α-pinene (6.6%), (E)-caryophyllene (19.1%) α-humulene (6.4%), δ-cadinene (6.5%), caryophyllene oxide (4.3%), α-cadinol (9.5%), and shyobunol (4.6%). The most sensitive microorganisms for EOOF were B. subtilis, S. aureus, and C. albicans with inhibition zones of 34, 16, and 24 mm and MIC values of, 4.3 mg/mL, 4.3 mg/mL, and 8.6 mg/mL, respectively. EOTY-t showed antimicrobial activity against S. aureus, B. cereus, A. niger, and B. cinerea with MIC values of 0.156, 0.156, 0.313 and 0.313 mg/mL, respectively. Neither essential oil showed remarkable radical inhibition (IC50 = 31.55 and 31.41 μL/mL). EOTY-d was active against HT-29 human colorectal adenocarcinoma cell lines with IC50 = 43.7 μg/mL. Consistent with this, EOTY-t was active against both MCF-7 and MDA-MB-231 human breast adenocarcinoma cells. Conclusions: The antimicrobial activity of Ocimum forskolei essential oil against B. subtilis and C. albicans is consistent with its traditional use in Yemeni traditional medicine to treat skin infections. Both O. forskolei and T. yemense show wide variations in their respective essential oil compositions; there remains a need to investigate both species botanically, genetically, and phytochemically more comprehensively.
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