Untargeted Metabolomics Approach for the Discovery of Environment-Related Pyran-2-ones Chemodiversity in a Marine-Sourced Penicillium restrictum.

Van-Tuyen Le,Sandra Bourgeade-Delmas,Fabrice Fleury,Olivier Grovel,Cedric Logé,Gregory Genta-Jouve,Thibaut Robiou Du Pont,Samuel Bertrand,Emmanuel Gentil,Nathalie Caroff

doi:10.3390/md19070378

Abstract

Very little is known about chemical interactions between fungi and their mollusc host within marine environments. Here, we investigated the metabolome of a Penicillium restrictum MMS417 strain isolated from the blue mussel Mytilus edulis collected on the Loire estuary, France. Following the OSMAC approach with the use of 14 culture media, the effect of salinity and of a mussel-derived medium on the metabolic expression were analysed using HPLC-UV/DAD-HRMS/MS. An untargeted metabolomics study was performed using principal component analysis (PCA), orthogonal projection to latent structure discriminant analysis (O-PLSDA) and molecular networking (MN). It highlighted some compounds belonging to sterols, macrolides and pyran-2-ones, which were specifically induced in marine conditions. In particular, a high chemical diversity of pyran-2-ones was found to be related to the presence of mussel extract in the culture medium. Mass spectrometry (MS)- and UV-guided purification resulted in the isolation of five new natural fungal pyran-2-one derivatives—5,6-dihydro-6S-hydroxymethyl-4-methoxy-2H-pyran-2-one (1), (6S, 1’R, 2’S)-LL-P880β (3), 5,6-dihydro-4-methoxy-6S-(1’S, 2’S-dihydroxy pent-3’(E)-enyl)-2H-pyran-2-one (4), 4-methoxy-6-(1’R, 2’S-dihydroxy pent-3’(E)-enyl)-2H-pyran-2-one (6) and 4-methoxy-2H-pyran-2-one (7)—together with the known (6S, 1’S, 2’S)-LL-P880β (2), (1’R, 2’S)-LL-P880γ (5), 5,6-dihydro-4-methoxy-2H-pyran-2-one (8), (6S, 1’S, 2’R)-LL-P880β (9), (6S, 1’S)-pestalotin (10), 1’R-dehydropestalotin (11) and 6-pentyl-4-methoxy-2H-pyran-2-one (12) from the mussel-derived culture medium extract. The structures of 1-12 were determined by 1D- and 2D-MMR experiments as well as high-resolution tandem MS, ECD and DP4 calculations. Some of these compounds were evaluated for their cytotoxic, antibacterial, antileishmanial and in-silico PTP1B inhibitory activities. These results illustrate the utility in using host-derived media for the discovery of new natural products.

Highlights

To explore the chemical diversity produced by P. restrictum MMS417 according to culture media, a complete metabolomics study was performed following the OSMAC
The strain was grown over six usual agar-based media—Czapek Yeast Agar (CYA), Dextrose Casein Agar (DCA), Potato Dextrose Agar (PDA), Yeast Extract Sucrose agar (YES), Malt Extract Agar (MEA) and Kohlmeyer-Medium Solid (KMS)
Colony morphology was observed throughout the culture growth (Figure S1), showing that the morphology of the strain was dramatically modified according to each medium

Summary

Introduction

Oysters, mussels and clams [1]. As filter feeders, these shellfish can actively retain and concentrates particles and micro-organisms from their surrounding environment such as bacteria [2], viruses [3,4], protozoa [5], and fungi [6,7,8]. Zvereva et al reported that fungal strains belonging to Aspergillus, Penicillium, Acremonium, and Alternaria genera are the most predominantly found in the two bivalve molluscs Crenomytilus grayanus and Modiolus modiolus [7]. Santos et al reported eight fungal genera, such as Aspergillus, Penicillium, and Fusarium from the gills, intestine, and muscle tissue of the Nodipectennodosus scallop from marine farms in Brazil [8].

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Conclusion