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Berlin Brandenburg

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  • 1
    Language: English
    In: Tetrahedron, 11 March 2013, Vol.69(10), pp.2296-2301
    Description: New eunicellin-base diterpenoids, hirsutalins I–M ( – ), were isolated from the soft coral . Their structures were elucidated by spectroscopic methods, particularly in 1D and 2D NMR experiments. The absolute configuration of was determined by Mosher's method. These compounds did not exhibit cytotoxicity toward a limited panel of cancer cell lines but showed nitric oxide inhibitory activity in LPS-stimulated RAW264.7 macrophage cells. Among them, compound was found to possess the strongest NO inhibitory activity with an IC value of 9.8 μg/mL. Furthermore, was shown to significantly reduce the expression iNOS protein in the same cells. New eunicellin-based diterpenoids, were isolated from the soft coral, .
    Keywords: Eunicellin-Base Diterpenoids ; Hirsutalins I–M ; Cytotoxicity ; No Inhibitory Activity ; Chemistry
    ISSN: 0040-4020
    E-ISSN: 1464-5416
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  • 2
    Language: English
    In: Tetrahedron Letters, 2012, Vol.53(3), pp.277-280
    Description: A new aromatic polyketide glycoside, indigotide A ( ), was isolated from the culture broth of the entomopathogenic fungus, , along with known cyclic depsipeptides, destruxins A, A , B, B and E ( – ), and a polyketide, NG-393 ( ). Repeated treatment of the . culture broth with 5-azacytidine, a DNA methyltransferase inhibitor, led to the isolation of another new aromatic polyketide glycoside, indigotide ( ).
    Keywords: Entomopathogenic Fungi ; Secondary Metabolites ; Polyketides ; DNA Methyltransferase Inhibitor ; Epigenetics ; Chemistry
    ISSN: 0040-4039
    E-ISSN: 1873-3581
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  • 3
    Language: English
    In: Tetrahedron, 25 November 2012, Vol.68(47), pp.9694-9700
    Description: Nine new steroids, sclerosteroids A–I ( , , , – ), along with 18 known metabolites ( – , , – ), were isolated from the soft coral These structures were elucidated on the basis of detailed spectroscopic analysis. The absolute configurations of sugar moieties in steroidal glycosides – were determined by HPLC analysis of the -tolylthiocarbamate derivatives of the liberated sugars from hydrolysis of these steroidal giycosides. Cytotoxic and anti-inflammatory activities of these compounds were measured in vitro.
    Keywords: Scleronephthya Gracillimum ; Sclerosteroids ; O-Tolylthiocarbamate ; Cytotoxic Activity ; Anti-Inflammatory Activity ; Chemistry
    ISSN: 0040-4020
    E-ISSN: 1464-5416
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  • 4
    Language: English
    In: PLoS ONE, 2012, Vol.7(5), p.e37764
    Description: Withanolides are a large group of steroidal lactones found in Solanaceae plants that exhibit potential anticancer activities. We have previously demonstrated that a withanolide, tubocapsenolide A, induced cycle arrest and apoptosis in human breast cancer cells, which was associated with the inhibition of heat shock protein 90 (Hsp90). To investigate whether other withanolides are also capable of inhibiting Hsp90 and to analyze the structure-activity relationships, nine withanolides with different structural properties were tested in human breast cancer cells MDA-MB-231 and MCF-7 in the present study. Our data show that the 2,3-unsaturated double bond-containing withanolides inhibited Hsp90 function, as evidenced by selective depletion of Hsp90 client proteins and induction of Hsp70. The inhibitory effect of the withanolides on Hsp90 chaperone activity was further confirmed using in vivo heat shock luciferase activity recovery assays. Importantly, Hsp90 inhibition by the withanolides was correlated with their ability to induce cancer cell death. In addition, the withanolides reduced constitutive NF-κB activation by depleting IκB kinase complex (IKK) through inhibition of Hsp90. In estrogen receptor (ER)-positive MCF-7 cells, the withanolides also reduced the expression of ER, and this may be partly due to Hsp90 inhibition. Taken together, our results suggest that Hsp90 inhibition is a general feature of cytotoxic withanolides and plays an important role in their anticancer activity.
    Keywords: Research Article ; Biology ; Medicine ; Molecular Biology ; Cell Biology ; Oncology ; Biochemistry
    E-ISSN: 1932-6203
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  • 5
    Language: English
    In: Tetrahedron Letters, 26 October 2016, Vol.57(43), pp.4842-4844
    Description: Total synthesis of optically pure (+)-Fuligocandin A from -proline has been achieved in 29% overall yield. The key step, one-pot reductive cyclodehydration of the chiral 2-nitrophenyl-1,3-dicarbonyl compound, proceeds with 〉98% retention of configuration. This method represents a convenient approach to the synthesis of 2-methylenebenzo[ ][1,4]diazepin-5-ones containing one chiral center. A series of benzo[ ][1,4]diazepin-5-one derivatives have been successfully synthesized with retention of chirality by the one-pot reaction developed in this work. A possible reductive cyclodehydration mechanism was also proposed.
    Keywords: (+)-Fuligocandin ; 2-Methylenebenzo[E][1,4]Diazepin-5-One ; Vinylogous Amide ; One-Pot Reductive Cyclodehydration ; Chemistry
    ISSN: 0040-4039
    E-ISSN: 1873-3581
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  • 6
    Language: English
    In: Tetrahedron Letters, 27 November 2013, Vol.54(48), pp.6529-6532
    Description: Xanthine oxidase (XO) is a key enzyme in purine metabolism with an important role in various pathologies. Several flavonoids have been reported for their capacity to inhibit this enzyme, and, for these compounds, the ability to adopt a planar 3D structure has been accepted as fundamental prerequisite for such activity. Here we report the in vitro investigation of a series of non-planar protoflavone derivatives as XO inhibitors, among which protoapigenone 1′- -propargyl ether was found to be an efficient competitive inhibitor of the enzyme with an IC value of 3.61 μM, significantly ( 〈0.001) stronger than the anti-gout drug allopurinol (IC = 8.72 μM). Methoxy substitution at C-7, however, resulted in complete loss of activity. In silico docking supported the observed structure–activity relationships, based on which a ‘planar structure’ itself can no longer be considered as a criterion for flavonoid-type inhibitors of XO.
    Keywords: Xanthine Oxidase Inhibitor ; Flavonoid ; Protoflavone ; Protoapigenone ; Structure–Activity Relationships ; Docking Study ; Chemistry
    ISSN: 0040-4039
    E-ISSN: 1873-3581
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  • 7
    Language: English
    In: Tetrahedron Letters, 20 June 2012, Vol.53(25), pp.3173-3177
    Description: A facile protocol toward several substituted 3-aryl-3,4,4a,10-tetrahydro-2 -anthracen-9-ones starting with substituted 2-allylbenzaldehydes was described. The overall synthetic process was carried out by the domino aldol condensation/Diels–Alder cycloaddition of skeleton with substituted cinnamaldehydes in an alkalic aqueous-methanolic solution followed by base-induced double migration of the resulting cycloadducts. Skeleton was prepared from isovanillin ( ) in moderate yield in five-steps via the known procedures with the synthetic sequence of O-allylation, Claisen rearrangement, O-methylation, Grignard methylation, and PCC-mediated oxidation.
    Keywords: Claisen Rearrangement ; Aldol Condensation ; Diels–Alder Cycloaddition ; One-Pot Combination ; Tetrahydroanthracen-9-Ones ; Chemistry
    ISSN: 0040-4039
    E-ISSN: 1873-3581
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  • 8
    Language: English
    In: Cancer Research, 10/01/2014, Vol.74(19 Supplement), pp.1637-1637
    ISSN: 0008-5472
    E-ISSN: 1538-7445
    Source: CrossRef
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  • 9
    Language: English
    In: PLoS ONE, 01 January 2015, Vol.10(10), p.e0141184
    Description: In this study, six 2-phenylnaphthalenes with hydroxyl groups were synthesized in high yields by the demethylation of the corresponding methoxy-2-phenylnaphthalenes, and one 2-phenylnaphthalene with an amino group was obtained by hydrogenation. All of the 2-phenylnaphthalene derivatives were evaluated for cytotoxicity, and the structure-activity relationship (SAR) against human breast cancer (MCF-7) cells was also determined. The SAR results revealed that cytotoxicity was markedly promoted by the hydroxyl group at the C-7 position of the naphthalene ring. The introduction of hydroxyl groups at the C-6 position of the naphthalene ring and the C-4' position of the phenyl ring fairly enhanced cytotoxicity, but the introduction of a hydroxyl group at the C-3' position of the phenyl ring slightly decreased cytotoxicity. Overall, 6,7-dihydroxy-2-(4'-hydroxyphenyl)naphthalene (PNAP-6h) exhibited the best cytotoxicity, with an IC50 value of 4.8 μM against the MCF-7 cell line, and showed low toxicity toward normal human mammary epithelial cells (MCF-10A). PNAP-6h led to cell arrest at the S phase, most likely due to increasing levels of p21 and p27 and decreasing levels of cyclin D1, CDK4, cyclin E, and CDK2. In addition, PNAP-6h decreased CDK1 and cyclin B1 expression, most likely leading to G2/M arrest, and induced morphological changes, such as nuclear shrinkage, nuclear fragmentation, and nuclear hypercondensation, as observed by Hoechst 33342 staining. PNAP-6h induced apoptosis, most likely by the promotion of Fas expression, increased PARP activity, caspase-7, caspase-8, and caspase-9 expression, the Bax/Bcl-2 ratio, and the phosphorylation of p38, and decreased the phosphorylation of ERK. This study provides the first demonstration of the cytotoxicity of PNAPs against MCF-7 cells and elucidates the mechanism underlying PNAP-induced cytotoxicity.
    Keywords: Sciences (General)
    E-ISSN: 1932-6203
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  • 10
    Language: English
    In: Tetrahedron, 22 July 2012, Vol.68(29), pp.5817-5823
    Description: The concomitant addition of a histone deacetylase inhibitor, suberoyl bis-hydroxamic acid, and a DNA methyltransferase inhibitor, RG-108, to the culture medium of , an entomopathogenic fungus, induced a significant increase in diversity of secondary metabolites. From the culture media were isolated two new highly oxidized ergosterols, formosterols A ( ) and B ( ), and five new isariotin analogs, 12′- -acetylisariotin A ( ), 1- -isariotin A ( ), and isariotins K–M ( – ), together with 22,23-epoxy-3,12,14,16-tetrahydroxyergosta-5,7-dien-11-one (named formosterol C) ( ), isariotins A ( ), C ( ), and E ( ), TK-57-164A ( ), and beauvericin ( ). The NMR spectra, X-ray single crystallographic diffraction, and chemical transformations revealed the structures of the two new formosterols and five new isariotins. The stereochemistry of formosterol C ( ) was deduced from its spectroscopic data. The side chains of formosterols A–C ( – ) contained -22,23-epoxide, which is rarely present in naturally occurring sterols and triterpenes.
    Keywords: Chemistry
    ISSN: 0040-4020
    E-ISSN: 1464-5416
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