691 research outputs found

    Scalarane-Based Sesterterpenoid RCE-Protease Inhibitors Isolated from the Indonesian Marine Sponge Carteriospongia foliascens

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    part of research collaboration between Mar Fish Faculty of Unhas and EOS UBCTwo new 20,24-bishomo-25-norscalaranes, compounds 1 and 2, and two new and two known 20,24-bishomoscalaranes, compounds 3???6, have been isolated from the Indonesian marine sponge Carteriospongia foliascens. The structures of 1???6 were determined by spectroscopic analysis. Compounds 1 and 3???6 inhibit RCE-protease activity

    Latonduines A and B, New Alkaloids Isolated from the Marine Sponge Stylissa carteri:??? Structure Elucidation, Synthesis, and Biogenetic Implications

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    Part of research collaboration results between Fac Mar Fish UNHAS and EOS UBCLatonduines A (6) and B (7), two new alkaloids with unprecedented heterocyclic skeletons, have been isolated from the Indonesian marine sponge Stylissa carteri. The structures of the latonduines were elucidated by analysis of spectroscopic data and confirmed by the total synthesis of latonduine A (6). It is proposed that ornithine is the biogenetic precursor to the aminopyrimidine fragment of the latonduines

    GARDINERIN, A BIOLOGICALLY ACTIVE ACETOGENIN FROM THE SRI LANKAN GONIOTHALAMUS GARDINERI HOOK. F. AND THOMSON

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    Objective: The study was undertaken to isolate biologically active compounds from Goniothalamus gardineri, a plant endemic to Sri Lanka. Methods: Roots and flowers of Goniothalamus gardineri were extracted into dichloromethane and methanol. A new acetogenin, gardinerin isolated by column chromatography of the dichloromethane extract was structurally characterized using NMR and Mass spectroscopies. It was found to be mosquito larvicidal (against 2nd instar larvae of Aedes aegypti), cytotoxic (in the brine shrimp assay) and antioxidant (DPPH assay). Results: Gardinerin exhibited potent mosquitolarvicidal activity (LC50 = 0.0744±0.37 ppm.), cytotoxicity (LC50 = 1.5±0.37 ppm) and antioxidant activity (IC50 =10.02±0.01 ppm). The same extract furnished (5R)-goniothalamin. The hexane extract of the flowers of G. gardineri yielded poriferesterol and stigmast-4, 22-dien-3-one.Conclusion: The endemic plant G. gardineri has yielded an acetogenin possessing highly potent antioxidant, cytotoxic and mosquitolarvicidal activity. Â

    Antioxidant neolignans from the twigs and leaves of Mitrephora wangii HU

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    Two new compounds, odoratisol E (1) and decurrenal A (2), together with 12 known compounds were isolated from the twig and leaf extracts of Mitrephora wangii HU (Annonaceae). All structures were elucidated by spectroscopic methods. The structure of compound (+)-6 was also confirmed by X-ray diffraction analysis. The absolute configurations of odoratisol E and decurrenal A were determined by comparison of their electronic circular dichroism (ECD) spectra with those of related known compounds. Most of the isolated compounds were evaluated for their antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays. Compounds 4 and (+)-6 displayed potent ABTS radical scavenging activity with IC50 values of 11.9 ± 1.8 and 10.8 ± 1.7 μM, respectively, which is better than that of standard compound, ascorbic acid, (IC50 = 19.3 ± 0.1 μM). Compound 9 showed moderate DPPH radical scavenging activity with an IC50 value of 38.7 ± 0.8 μM

    Resolution and identification of scalemic caged xanthones from the leaf extract of Garcinia propinqua having potent cytotoxicities against colon cancer cells

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    A new scalemic 8,8a-dihydro caged xanthone (1) was isolated from the leaf extract of Garcinia propinqua. Five other known natural products, the three caged xanthones (2, 5 and 6) and the two neocaged xanthones, (3 and 4) were also isolated as scalemic mixtures. Their structures were characterized by spectroscopic methods. The enantiomeric ratios (er) of compounds 1-6 ranged from 1:0.7 to 1:0.9. These compounds were also resolved by semipreparative chiral HPLC. The absolute configurations of (+)-2 and (+)-3 were determined by single-crystal X-ray diffraction analysis using Cu Kα radiation while the absolute configurations of the other compounds were determined by comparisons of their ECD spectra. Compounds (-)-4, (+)-4, (-)-5, (+)-5, and (-)-6 showed potent cytotoxicities against a colon cancer cell line HCT116 with IC50 values of 2.60, 7.02, 1.47, 3.37, and 4.14μM, respectively, which were better than the standard control doxorubicin (IC50 9.74μM)

    Regression of Castrate-Recurrent Prostate Cancer by a Small-Molecule Inhibitor of the Amino-Terminus Domain of the Androgen Receptor

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    SummaryCastration-recurrent prostate cancer (CRPC) is suspected to depend on androgen receptor (AR). The AF-1 region in the amino-terminal domain (NTD) of AR contains most, if not all, of the transcriptional activity. Here we identify EPI-001, a small molecule that blocked transactivation of the NTD and was specific for inhibition of AR without attenuating transcriptional activities of related steroid receptors. EPI-001 interacted with the AF-1 region, inhibited protein-protein interactions with AR, and reduced AR interaction with androgen-response elements on target genes. Importantly, EPI-001 blocked androgen-induced proliferation and caused cytoreduction of CRPC in xenografts dependent on AR for growth and survival without causing toxicity
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