Erylusamides: Novel Atypical Glycolipids from Erylus cf. deficiens

Abstract

Among marine organisms, sponges are the richest sources of pharmacologically-active compounds. Stemming from a previous lead discovery program that gathered a comprehensive library of organic extracts of marine sponges from the off-shore region of Portugal, crude extracts of Erylus cf. deficiens collected in the Gorringe Bank (Atlantic Ocean) were tested in the innovative high throughput screening (HTS) assay for inhibitors of indoleamine 2,3-dioxygenase (IDO) and showed activity. Bioassay guided fractionation of the dichloromethane extract led to the isolation of four new glycolipids, named erylusamide A–D. The structures of the isolated compounds were established by 1D and 2D nuclear magnetic resonance (NMR) spectroscopy, high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) and chemical derivatization. The metabolites shared a pentasaccharide moiety constituted by unusual highly acetylated d-glucose moieties as well as d-xylose and d-galactose. The aglycones were unprecedented long chain dihydroxyketo amides. Erylusamides A, B and D differ in the length of the hydrocarbon chain, while erylusamide C is a structural isomer of erylusamide B.

Marine natural products

“…Nonetheless, sponges are still an important taxonomic group for the discovery of new, bioactive natural products. A number of new glyceride (788 and 789) and ceramide (790-793) lipids have been reported from species of Theonella and Erylus, 394,395 while branched fatty acids (794 and 795), polyoxygenated fatty acid amides (796 and 797) and N-acyldopamine glycosides 798-801 were sourced from Asteropus, Melonanchora, Myxilla and Theonella sponges. [396][397][398][399] Unusually, only one new polyacetylene 802 was reported in 2016, from Halichondria panicea.…”

Melonoside B and Melonosins A and B, Lipids Containing Multifunctionalized ω-Hydroxy Fatty Acid Amides from the Far Eastern Marine Sponge Melonanchora kobjakovae

“…Marine sponges have been reported to be a source of rare oxygenated fatty acid amides with unprecedented chemical structures and biological activities. − Recently we have isolated and structurally elucidated the first member of a new class of ω- O -glycosylated polyoxygenated fatty acid amides, melonoside A ( 4 ), from the marine sponge Melonanchora kobjakovae . Three related compounds, named myxillines A–C, were almost simultaneously isolated from the marine sponge Myxilla incrustans by Icelandic chemists .…”

A Soft Spot for Chemistry–Current Taxonomic and Evolutionary Implications of Sponge Secondary Metabolite Distribution

“…Naturally acetylated glycolipids are rarely occurring compounds in sponges, mainly reported from the geodiid taxa Caminus , Pachymatisma and Erylus , making them a potentially distinct marker for Geodiidae [ 103 ]. Contradicting this assessment are however discoveries in the Axinellida genera Trikentrion and Myrmekioderma, e.g., [ 104 ].…”