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Isolation of New Secondary Metabolites from New Zealand Marine Invertebrates

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posted on 2021-11-08, 01:48 authored by Wojnar, Joanna M

This study describes the isolation and structure elucidation of several known and 13 new compounds from New Zealand marine organisms. Furthermore, it describes the development of a digital mask program for the analysis of HSQC spectra of crude sponge extracts. This was used as a screening tool to identify secondary metabolite producers that warranted further analysis. As reports of metabolites from New Zealand nudibranchs are poorly represented in the literature, a study of five New Zealand nudibranch species was undertaken. These coloured and seemingly undefended nudibranchs are known to concentrate or sequester toxic metabolites from their prey, facilitating rapid isolation and structure elucidation of these metabolites. This study resulted in the isolation of a variety of metabolite classes; two new compounds, 13alpha- acetoxypukalide diol (30) and lopholide diol (31) from the nudibranch Tritonia incerta, are described. Examination of the sponge Raspailia agminata resulted in the isolation of a novel family of partially acetylated glycolipids which contain up to six glucose residues. The chromatographic separation of these compounds was a challenge due to the similarity of the congeners and their lack of a chromophore. MSguided isolation eventually led to the purification of agminosides A-E (145-149). An unidentified sponge of the order Dictyoceratida was found to contain a new isomer (186) of the known sesterterpene variabilin. As variabilin-type compounds are predominantly found from sponges of the family Irciniidae, the unidentified sponge is most likely an irciniid. In addition, the sponge contained two prenylated quinones, one of which, 189, is a new isomer of a known sponge metabolite. The sponge Darwinella oxeata contained four new nitrogenous diterpenes of the aplysulphurane (rearranged spongian) skeleton, oxeatamide A (214), isooxeatamide A (215), oxeatamide A 23-methyl ester (216) and oxeatamide B (217).

History

Copyright Date

2008-01-01

Date of Award

2008-01-01

Publisher

Te Herenga Waka—Victoria University of Wellington

Rights License

Author Retains Copyright

Degree Discipline

Chemistry

Degree Grantor

Te Herenga Waka—Victoria University of Wellington

Degree Level

Doctoral

Degree Name

Doctor of Philosophy

Victoria University of Wellington Item Type

Awarded Doctoral Thesis

Language

en_NZ

Victoria University of Wellington School

School of Chemical and Physical Sciences

Advisors

Northcote, Peter