11 results for Page, MJ

  • E/Z-Rubrolide O, an Anti-inflammatory Halogenated Furanone from the New Zealand Ascidian Synoicum n. sp.

    Pearce, Allison; Chia, EW; Berridge, MV; Maas, E; Page, MJ; Webb, VL; Harper, JL; Copp, Brent (2007)

    Journal article
    The University of Auckland Library

    Bioassay-directed fractionation of extracts of a Synoicum n. sp. ascidian from New Zealand led to the isolation of the principal anti-inflammatory component, which was identified by spectroscopic methods as a new member of the rubrolide family, rubrolide O (1), existing as a mixture of E/Z isomers.

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  • Orthidines A - E, tubastrine, 3,4-dimethoxyphenethyl-b-guanidine and 1,14-sperminedihomovanillamide: potential anti-inflammatory alkaloids isolated from the New Zealand ascidian Aplidium orthium that act as inhibitors of neutrophil respiratory burst.

    Pearce, Allison; Chia, EW; Berridge, MV; Maas, E; Page, MJ; Harper, JL; Webb, VL; Copp, Brent (2008)

    Journal article
    The University of Auckland Library

    In addition to the known dihydroxystyrylguanidine alkaloid tubastrine (1), five new dimers, orthidines A???E (2???6) and the biosynthetically unrelated 1,14-sperminedihomovanillamide (orthidine F, 7) were isolated from the New Zealand ascidian Aplidium orthium. The structures of the new compounds, elucidated by interpretation of spectroscopic data, encompass benzodioxane neolignan-type scaffolds (2???5) and a 1,2,3,4-tetrasubstituted cyclobutane (6), the latter likely having arisen via [p2s??p2s] dimerization of tubastrine. The subunit head-to-tail orientation of dimer 6 was established unambiguously by interpretation of data from a 2J,3J-HMBC NMR experiment. The structure of 7 was also confirmed by facile synthesis. Compounds 1???4, 6, and 7 inhibited the in vitro production of superoxide by PMA-stimulated human neutrophils in a dose-dependent manner with IC50s of 10???36 mM and this was associated with inhibition of superoxide production by neutrophils in vivo in a murine model of gouty inflammation.

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  • Anti-inflammatory Thiazine Alkaloids Isolated from the New Zealand Ascidian Aplidium sp.; Inhibitors of the Neutrophil Respiratory Burst in a Model of Gouty Arthritis.

    Pearce, Allison; Chia, EW; Berridge, MV; Clark, George; Harper, JL; Larsen, L; Maas, E; Page, MJ; Perry, NB; Webb, VL; Copp, Brent (2007)

    Journal article
    The University of Auckland Library

    Ascidiathiazones A (3) and B (4), two new tricyclic thiazine-containing quinolinequinone alkaloids, were isolated from the New Zealand ascidian Aplidium species. Both compounds inhibited the in vitro production of superoxide by PMA-stimulated human neutrophils in a dose-dependent manner with IC50 1.55 ?? 0.32 and 0.44 ?? 0.09 ??M, respectively. In vivo inhibition of superoxide production by peritoneal neutrophils in a murine model of gout was observed for both compounds with oral doses of 25.6 ??mol/kg. Ascidiathiazone A (3) was synthesized in four steps from 8-hydroxyquinoline-2-carboxylic acid.

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  • Didemnidines A and B, indole spermidine alkaloids from the New Zealand ascidian Didemnum sp.

    Finlayson, R; Pearce, Allison; Page, MJ; Kaiser, M; Bourguet-Kondracki, M-L; Harper, JL; Webb, VL; Copp, Brent (2011-02-24)

    Journal article
    The University of Auckland Library

    Two new indole spermidine alkaloids, didemnidines A (1) and B (2), have been isolated from the New Zealand ascidian Didemnum sp. The structures of the metabolites, determined by analysis of 2D NMR spectra and confirmed via synthesis, embody an indole-3-glyoxylamide moiety linked to the N(1) position of spermidine, the latter motif being particularly rare among marine natural products. Didemnidine B and a synthetic precursor exhibited mild in vitro growth inhibition of Plasmodium falciparum with IC(50)'s of 15 and 8.4 ??M, respectively.

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  • Antimalarial ??-Carbolines from the New Zealand Ascidian Pseudodistoma opacum

    Chan, STS; Pearce, Allison; Page, MJ; Kaiser, M; Copp, Brent (2011-09-23)

    Journal article
    The University of Auckland Library

    One tetrahydro-??-carboline, (-)-7-bromohomotrypargine (1), and three alkylguanidine-substituted ??-carbolines, opacalines A, B, and C (2-4), have been isolated from the New Zealand ascidian Pseudodistoma opacum. The structures of the metabolites were determined by analysis of mass spectrometric and 2D NMR spectroscopic data. Natural products 2 and 3, synthetic debromo analogues 8 and 9, and intermediate 16 exhibited moderate antimalarial activity toward a chloroquine-resistant strain of Plasmodium falciparum, with an IC50 range of 2.5-14 ??M. The biosynthesis of 1-4 is proposed to proceed via a Pictet-Spengler condensation of 6-bromotryptamine and the ??-keto acid transamination product of either arginine or homoarginine. Cell separation and 1H NMR analysis of P. opacum identified tetrahydro-??-carboline 1 to be principally located in the zooids, while fully aromatized analogues 2-4 were localized to the test.

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  • Anti-inflammatory and Antimalarial Meroterpenoids from the New Zealand Ascidian Aplidium scabellum.

    Chan, ST; Pearce, Allison; Januario, AH; Page, MJ; Kaiser, M; McLaughlin, RJ; Harper, JL; Webb, VL; Barker, David; Copp, Brent (2011-10-03)

    Journal article
    The University of Auckland Library

    Bioassay-directed fractionation of an extract of the New Zealand ascidian Aplidium scabellum has afforded the anti-inflammatory secondary metabolite 2-geranyl-6-methoxy-1,4-hydroquinone-4-sulfate (1) and a family of pseudodimeric meroterpenoids scabellones A (2)-D (5). The benzo[c]chromene-7,10-dione scaffold contained within scabellones A-D is particularly rare among natural products. The structures were elucidated by interpretation of NMR data. Scabellone B was also identified as a moderately potent, nontoxic inhibitor of Plasmodium falciparum.

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  • Biologically Active Acetylenic Amino Alcohol and N-Hydroxylated 1,2,3,4-Tetrahydro-??-carboline Constituents of the New Zealand Ascidian Pseudodistoma opacum

    Wang, J; Pearce, Allison; Chan, STS; Taylor, Richard; Page, MJ; Valentin, A; Bourguet-Kondracki, M-L; Dalton, James; Wiles, Siouxsie; Copp, Brent (2016-03)

    Journal article
    The University of Auckland Library

    The first occurrence of an acetylenic 1-amino-2-alcohol, distaminolyne A (1), isolated from the New Zealand ascidian Pseudodistoma opacum, is reported. The isolation and structure elucidation of 1 and assignment of absolute configuration using the exciton coupled circular dichroism technique are described. In addition, a new N-9 hydroxy analogue (2) of the known P. opacum metabolite 7-bromohomotrypargine is also reported. Antimicrobial screening identified modest activity of 1 toward Escherichia coli, Staphylococcus aureus, and Mycobacterim tuberculosis, while 2 exhibited a moderate antimalarial activity (IC50 3.82 ??M) toward a chloroquine-resistant strain (FcB1) of Plasmodium falciparum.

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  • Isolation and stereospecific synthesis of janolusimide B from a New Zealand collection of the bryozoan Bugula flabellata

    Wang, J; Prinsep, MR; Gordon, DP; Page, MJ; Copp, Brent (2014-12-10)

    Journal article
    The University of Auckland Library

    NMR-directed screening of New Zealand marine organisms has led to the isolation of the modified tripeptide janolusimide B from the common invasive bryozoan Bugula flabellata. The structure was established by NMR and MS analysis, degradative hydrolysis and derivatization, and stereoselective fragment synthesis. The bryozoan natural product is an N-methyl analogue of janolusimide, previously reported from the Mediterranean nudibranch Janolus cristatus, a species known to prey upon bryozoa.

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  • Kottamides A-D: Novel bioactive imidazolone-containing alkaloids from the New Zealand ascidian Pycnoclavella kottae

    Appleton, David; Page, MJ; Lambert, G; Berridge, MV; Copp, Brent (2002)

    Journal article
    The University of Auckland Library

    Kottamides A???D (1???4), novel 2,2,5-trisubstituted imidazolone-containing alkaloids, were isolated from the New Zealand endemic ascidian Pycnoclavella kottae and structurally characterized using 15N natural abundance 2-D NMR in addition to standard spectroscopic methods. The kottamides exhibited anti-inflammatory and anti-metabolic activity as well as cytotoxicity toward tumor cell lines.

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  • 1,3-dimethyl-8-oxoisoguanine, a new purine from the New Zealand ascidian Pseudodistoma Cereum

    Appleton, David; Page, MJ; Lambert, G; Copp, Brent (2004-02)

    Journal article
    The University of Auckland Library

    A new purine, 1,3-dimethyl-8-oxoisoguanine (2) was isolated from the New Zealand ascidian Pseudodistoma cereum. The structure of 2 was elucidated by the use of standard spectroscopic techniques, including natural abundance H-1-N-15 2D NMR.

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  • Isolation and characterization of the new purine 1,3,7-trimethylisoguanine from the New Zealand ascidian Pseudodistoma cereum

    Copp, Brent; Wassvik, Carola; Lambert, G; Page, MJ (2000)

    Journal article
    The University of Auckland Library

    The new purine 1,3,7-trimethylisoguanine (1) has been isolated from the ascidian Pseudodistoma cereum. The structure of 1 was elucidated by analysis of NMR spectroscopic and mass spectrometric data and by comparison with the regioisomeric purine 1,3,7-trimethylguanine (2).

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