# New Compounds From the Deep‐sea Sponge Mycale lingua

## TL;DR

This study isolated and characterized four compounds from the deep-sea sponge Mycale lingua, but none showed potential for treating Alzheimer's disease.

## Contribution

The first isolation of asterubine and sulcatin from M. lingua and the discovery of two new sulcatin analogues.

## Key findings

- Asterubine and sulcatin were first isolated from Mycale lingua.
- Two new sulcatin analogues, sulcatin B and C, were identified.
- None of the compounds inhibited tau aggregation in Alzheimer's assays.

## Abstract

Three compatible solutes and one compound of unknown ecological function were isolated and characterized from the deep‐sea sponge Mycale lingua (Bowerbank, 1866), collected from Tisler reef in Norway. These included the first isolation of asterubine and sulcatin from M. lingua as well as two new sulcatin analogues, sulcatin B and sulcatin C, which have not previously been reported from natural sources. Compound structures were elucidated through high‐resolution liquid chromatography‐mass spectrometry, and one‐ and two‐dimensional nuclear magnetic resonance spectroscopic methods. All four compounds were tested in tau‐tau aggregation assays to determine if they had potential for the treatment of Alzheimer's disease. No activity was displayed in either the cell‐free or cell‐based tau aggregation assays for any of the compounds.

The focus of this study is the scarcely investigated sponge Mycale lingua, found commonly in the North Atlantic Ocean. In total, four compounds are isolated and characterised from three combined M. lingua individuals. Structures are fully elucidated through HR‐LCMS and NMR spectroscopy (1H, COSY, HSQC, HMBC). Circular dichroism measurements and application of the octant rule are used to assign tentative absolute configurations. None of the compounds display activity against Alzheimer's disease through inhibition of tau‐tau protein aggregation.