Exploring marine sponges and their associated microorganisms as a source of natural compounds

• Main Author: Costa, Margarida
• Other Authors: Margrét Þorsteinsdóttir, Lyfjafræðideild (HÍ), Faculty of Pharmaceutical Sciences (UI), Heilbrigðisvísindasvið (HÍ), School of Health Sciences (UI), Háskóli Íslands, University of Iceland
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: University of Iceland, School of Health Sciences, Faculty of Pharmaceutical Sciences 2018
• Subjects: Marine natural products; Marine sponges; Actinomycetes; Secondary metabolites; Bioactivity; Sjávarnáttúruefni; Svampdýr; Gerlar; Efnasambönd; Lífvirkni; Hafið; Lyfjafræði; Doktorsritgerðir; Pacific; Iceland
• Online Access: https://hdl.handle.net/20.500.11815/950

The ocean represents a tremendous source of biologically active metabolites with great potential for the development of new pharmaceuticals. Marine sponges and their microbial associates are known as the most prolific source of structurally diverse and unique secondary metabolites. The present work aimed to explore the potential of different sponge and sponge-associated microorganisms as a source of natural compounds with possible pharmacological applications. Five sponge individuals collected in the Icelandic waters, three in the Indo-Pacific Ocean and two sponge-associated actinomycete strains were used for that purpose. Cytotoxic, anti-bacterial and anti-obesity activities were tested. Organic extracts were prepared from the five sponges collected in Iceland. The apolar extracts were found to be rich in fatty acids. The UPLC-QTOF-MS method used for dereplication of the present natural compounds was successfully optimized in order to increase efficiency when analyzing polar extracts. Seven known nucleosides and a nucleobase were dereplicated. The compounds were isolated and their structure confirmed by 1H-NMR. The Icelandic sponge's study was, however, discontinued due to the absence of promising extracts. Three sponge specimens collected in the Indo-Pacific Ocean were studied: Acanthostrongylophora sp., Acanthodendrilla sp. and Acanthostrongylophora ingens. Acanthostrongylophora sp. methanolic extract resulted in the isolation of haploscleridamine and a new nitrogenated analog. Acanthodendrilla sp. was found to be the producer of two spongian diterpenes with novel structures. This discovery withdrew Acanthodendrilla of being the only Dendroceratida genus that had not been reported as a producer of this class of compounds. Acanthostrongylophora ingens revealed to be the producer of five new bisabolane related compounds, the previously reported 6-(1,5-dimethyl-1,4-hexadienyl)-3-methylbenzene-1,4-diol and 1-(2,4-dihydroxy-5-methylphenyl)ethan-1-one. The bioactivity studies showed that ...