Poecillastrosides, Steroidal Saponins from the Mediterranean Deep-Sea Sponge Poecillastra compressa (Bowerbank, 1866).

Thierry Pérez,Bassam Soussi,Elaheh Lotfi Kalahroodi,Olivier P Thomas,Daniel Rodrigues,Mercedes De La Cruz,Fernando Reyes,Bastien Cautain,Caridad Díaz,Kevin Calabro,Rémi Laville

doi:10.3390/md15070199

Abstract

The first chemical investigation of the Mediterranean deep-sea sponge Poecillastra compressa (Bowerbank, 1866) led to the identification of seven new steroidal saponins named poecillastrosides A–G (1–7). All saponins feature an oxidized methyl at C-18 into a primary alcohol or a carboxylic acid. While poecillastrosides A–D (1–4) all contain an exo double bond at C-24 of the side-chain and two osidic residues connected at O-2′, poecillastrosides E–G (5–7) are characterized by a cyclopropane on the side-chain and a connection at O-3′ between both sugar units. The chemical structures were elucidated through extensive spectroscopic analysis (High-Resolution Mass Spectrometry (HRESIMS), 1D and 2D NMR) and the absolute configurations of the sugar residues were assigned after acidic hydrolysis and cysteine derivatization followed by LC-HRMS analyses. Poecillastrosides D and E, bearing a carboxylic acid at C-18, were shown to exhibit antifungal activity against Aspergillus fumigatus.

Highlights

In the marine environment, steroid and triterpenoid glycosides are widespread metabolites mainly produced by echinoderms [1,2,3], saponins have been isolated from other marine invertebrates such as octocorals or sponges [4,5]
The methanolic fraction fraction was purified by successive RP‐Phenylhexyl and C18 yielding was purified by successive
The structures of poecillastrosides E–G (5–7) incorporate a terminal methylated cyclopropyl ring already known in some sponge steroids and already investigated for biosynthetic studies [56]

Summary

Introduction

Steroid and triterpenoid glycosides are widespread metabolites mainly produced by echinoderms [1,2,3], saponins have been isolated from other marine invertebrates such as octocorals or sponges [4,5]. About 70 saponins have been reported from sponges [6] including sarasinosides from Asteropus spp. Mar. Drugs 2017, 15, 199; doi:10.3390/md15070199 www.mdpi.com/journal/marinedrugs. Two acanthifoliosides sponges [19], erylosides, sokodosides, nobiloside, and wondosterols formosides from spp. Ptilocaulis spiculifer [30],nobiloside, mycalosides from. Mycale laxissima [31,32],spp. feroxosides two sponges [19],from erylosides, sokodosides, and formosides from Erylus [20,21,22,23,24,25,26,27,28,29], from Ectyoplasia ferox and silenosides frommycalosides. Whilelaxissima some sponge can ptilosaponosides from[33], Ptilocaulis spiculifer [30], from. Two acanthifoliosides sponges [19], erylosides, sokodosides, nobiloside, and wondosterols formosides from spp. [20,21,22,23,24,25,26,27,28,29], and from Pandaros acanthifolium [15,16,17,18], fromErylus the association of ptilosaponosides

Methods

Discussion

Conclusion