Exploring marine sponges and their associated microorganisms as a source of natural compounds
Year: 2018
Type: dissertation
Abstract: 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. \nOrganic 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. \nThree 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 6-(1,5-dimethyl-1,4-hexadienyl)-3-methylbenzene-1,4-diol have moderate cytotoxic activity against the tested cancer cell lines. Bisabolane-related compounds also demonstrated to have anti-obesity potential based on the zebrafish Red Nile assay. \nThe actinomycete strain DIL-12-02-135 mycelial cake was found to contain two group C fluvirucinins. Those compounds were obtained through mass spectrometry-guided isolation and represent the first isolation of this class of compounds from marine sources. Another mass spectrometry-guided isolation carried out in the actinomycete strain CP9-13-01-036 yielded two known compounds: mangrolide A and a naphthoquinone. Naphtoquinone was shown to have both strong cytotoxic activity against the tested cell lines and anti-bacterial activity against Staphylococcus aureus. \nThe studied marine sponges and actinomycete strains resulted in several known and new compounds with valuable bioactivities. Marine sponges demonstrated, once again, to be a tremendous source of bioactive natural compounds.
Source: Opin vísindi (Opin vísindi)
Author: Margarida Costa
Language: English
Subfield: Biotechnology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2949206903