Isolation and characterisation of secondary metabolites from arctic, marine invertebrates

Abstract

Bioprospecting is the systematic search for and discovery of products in nature, with the purpose of developing commercial products. The marine environment displays a rich biological diversity, as well as a diversity within environmental factors. This environment has necessitated the production of potent secondary metabolites by marine organisms in their arms race against predators and pathogens, in the battle for space and to increase chances of reproduction. The resulting compounds are generally known to have unique chemical features, often unknown from terrestrial sources, as well as interesting biological activities. Due to these factors, they are believed to hold an immense potential as lead compounds in development of commercial products. The aim of this thesis was to isolate and characterise secondary metabolites from extracts of eight Arctic, marine invertebrates. Prefractionated extracts were screened for anticancer activity, and active fractions were dereplicated to investigate if the bioactive compound(s) was novel or had been previously reported. Three compounds believed to be novel were isolated, structure elucidated and biologically characterised. A novel compound, named BI-L-665.6 in this thesis, was isolated from the organic extract of Bryozoa indet. In addition, Ponasterone A (Pon A) and dehydroxy-Pon A were isolated from the organic extract of Alcyonidium gelatinosum. Pon A was first isolated from Podocarpus nakaii in 1966, but this is the first time that this compound has been isolated from A.gelatinosum. Biological characterisation of the isolated compounds detected no anticancer or antibacterial activity at the test concentrations employed in the assays. The results from this thesis show that bioprospecting of collected marine invertebrates enables discovery of secondary metabolites with novel chemistry, as well as previously reported compounds in new species.