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Email:
Robin B. Gasser· - [email protected]; Rohan A. Davis· - [email protected]
Beilstein J. Org. Chem. 2022, 18, 1544-1552. https://doi.org/10.3762/bjoc.18.164
Received: 05 August 2022
Accepted: 03 November 2022
Published: 15 November 2022
Associate Editor: S. Bräse
©2022 Hayes et al.; licensee Beilstein-lnstitut.
License and terms: see end of document.
Keywords:
alkaloid; anthelmintic; biodiscovery; bromotyrosine; 5-debromopurealidin H; lanthella', NatureBank; sponge
Abstract
In order to further expand the NatureBank open access compound library, chemical investigations of the Australian marine sponge. Ianthella basta, were undertaken since UHPLC-MS analysis of the extract from this sponge indicated the presence of a new alkaloid. Large-scale extraction and mass-directed isolation studies on the CH2Cl2/MeOH I. basta extract resulted in the purification of a new bromotyrosine-derived alkaloid. 5-debromopurealidin H (1). along with the known marine natural product, ianthesine E (2). The chemical structure of the new compound was determined following detailed spectroscopic and spectrometric data analysis. These two compounds (1 and 2) along with seven previously reported marine bromotyrosine alkaloids from the NatureBank open access library, which included psammaplysins F (3) and H (4). bastadins 4 (5). 8 (6) and 13 (7). aerothionin (8) and hexadellin A (9). were evaluated for their nematocidal activity against exsheathed third-stage larvae of Haemonchus contortus. a highly pathogenic parasite of ruminants. Of the nine compounds, bastadin 8 (6). hexadellin A (9) and bastadin 4 (5) showed inhibition towards larval motility after 72 h of exposure with IC50 values of 1.6 μM. 10.0 μM and 33.3 μM. respectively.
Introduction
Marine sponges have been a significant source of unique chemistry over the past 70 years, with 11.863 sponge-derived secondary metabolites currently reported in the literature [1]. This equates to «30% of all marine natural products identified to date, an impressive contribution. Whilst many marine natural product chemists have shifted their attention to marine-derived microorganisms such as bacteria and fungi over the past 10 years [2], sponges continue to be a source of novel and biologically active metabolites and remain an important taxonomic phylum for the discovery of new and bioactive natural products, warranting inclusion in current and future biodiscovery programs.
Verongid sponges have been a prolific source of bioactive and novel bromotyrosine-derived alkaloids with more than 374 compounds currently reported [1]....