Secondary metabolites of Bagassa guianensis Aubl. wood: A study of the chemotaxonomy of the Moraceae family

International audienceIn order to explain the durability of the Moraceae plant family, phytochemistry of Bagassa guianensis was performed. Ethyl acetate extract was obtained from the heartwood and 18 secondary metabolites were isolated, including 6 moracins [6-O-methyl-moracin M, 6-O-methyl-moracin N and moracin Z; previously identified: moracin M, moracin N and moracin P], 8 stilbenoids [presently identified: ( )-epialboctalol and arachidin 4; previously identified: alboctalol, trans-resveratrol, arachidin 2, trans-oxyresveratrol and artogomezianol], 3 previously identified flavonoids, steppogenin, katuranin and dihydromorin, bsitosterol and resorcinol. Previous studies suggest that stilbenoids are responsible for the natural durability of wood. Our study has determined that B. guianensis is closely related to Morus sp. in phylogeny and should be included in the Moreae sensu stricto tribe of the Moraceae family

Analytical approaches to answer questions on the chemical ecology of holobionts

1re Journée de conférence et de rencontre autour de l’Écologie Chimique à l’Université Paris-Saclay. Paris-Saclay Pôle Biologie - Pharmacie- Chimie (BPC), France

Antifungal Agents from Pseudallescheria boydii SNB-CN73 Isolated from a Nasutitermes sp. Termite

International audienc

Etude de substances bioactives issues de la flore amazonienne (analyse de préparations phytothérapeutiques à base de Quassia amara L (simaroubacae) et Psidium acutangulum DC (Myrtaceae) utilisées en Guyane française pour une indication antipaludique)

L objectif du travail effectué était la recherche de nouvelles substances actives d origine végétale, présentant soit une activité antiplasmodiale soit une activité antifongique. Cette étude a été menée suivant deux stratégies différentes: l étude de remèdes traditionnels antipaludiques identifiés suite à des enquêtes ethnopharmacologiques, et la mise en évidence des propriétés antifongiques d huiles essentielles grâce à une stratégie bioinspirée. La première partie du travail a permis de mettre en évidence le rôle d un quassinoïde connu, la simalikalactone D, dans l activité antipaludique d une tisane de jeunes feuilles fraîches de Quassia amara L. (Simaroubaceae). Dans le cas de la décoction de rameaux de Psidium acutangulum DC. (Myrtaceae), c est cette fois un mélange de flavonoïdes glycosylés qui est responsable de l activité du remède. Dans le cadre de la recherche de nouvelles substances antifongiques, le criblage effectué a permis d identifier de nombreuses huiles essentielles présentant des activités intéressantes, validant ainsi la démarche bioinspirée retenue dans ce cas. L huile essentielle d Otacanthus azureus (Linden) Ronse a en particulier démontré une activité remarquable, à la fois seule et en combinaison avec des antifongiques azolés. Enfin, l étude métabolomique de la composition des huiles essentielles a permis de mettre au point un outil pouvant orienter la sélection des huiles en fonction des données obtenues en GC/MS dans l optique de la recherche de nouvelles substances antifongiques. Ce travail démontre donc la validité des stratégies retenues ethnopharmacologie et bioinspiration dans la recherche de nouvelles substances bioactives.The aim of this work was to search for new bioactive compounds, displaying either antiplasmodial or antifungal activity. Two strategies were developed here: the evaluation of traditional remedies identified as antimalarial through ethnopharmacological studies, and the search for antifungal essential oils, the criterium being here a bioinspired approach. Our work led to the discovery that the antimalarial activity of Quassia amara L. (Simaroubaceae) fresh young leaves was due to the presence of a known quassinoid, simalikalactone D. In the case of Psidium acutangulum DC. (Myrtaceae), a flavonol glycosides mixture explained the activity observed for the decoction. The search for antifungal essential oils from the Amazonian flora led to the identification of several interesting species, thus validating our bioinspired strategy. The essential oil of Otacanthus azureus (Linden) Ronse was among the most active ones, either alone or in combination with azole drugs. Eventually, a metabolomic study of the GC/MS composition of these oils allowed us to develop a statistical tool which could help to select interesting antifungal products. This work thus demonstrates the major interest of the two strategies ethnopharmacology and bioinspiration for the search of new bioactive compounds.CAYENNE-BU (973022101) / SudocSudocFranceF

Nitrogen Enriched Solid-State Cultivation for the Overproduction of Azaphilone Red Pigments by Penicillium sclerotiorum SNB-CN111

Azaphilones are microbial specialized metabolites employed as yellow, orange, red or purple pigments. In particular, yellow azaphilones react spontaneously with functionalized nitrogen groups, leading to red azaphilones. In this study, a new two-step solid-state cultivation process to produce specific red azaphilones pigments was implemented, and their chemical diversity was explored based on liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) and a molecular network. This two-step procedure first implies a cellophane membrane allowing accumulating yellow and orange azaphilones from a Penicillium sclerotiorum SNB-CN111 strain, and second involves the incorporation of the desired functionalized nitrogen by shifting the culture medium. The potential of this solid-state cultivation method was finally demonstrated by overproducing an azaphilone with a propargylamine side chain, representing 16% of the metabolic crude extract mass

Études chimique et biologique de plantes tropicales (Disepalum plagioneurum et Richella obtusata (Annonaceae), Argophyllum nitidum (Escalloniaceae), et Pittosporum pancheri (Pittosporaceae))

Dans le cadre de la recherche de nouvelles molécules bioactives, l'étude chimique de quatre plantes a été entreprise: deux Annonaceae cytotoxiques (Disepalum plagioneurum et Richella obtustata), une Escalloniaceae inhibitrice de l'acétylcholinestérase (Argophyllum nitidum) et une Pittosporaceae inhibitrice du récepteur MCH1 (Pittosporum pancheri). Le fractionnement bioguidé de ces plantes et les modifications chimiques de certaines molécules isolées ont permis la détermination de 17 composés (dont 13 sont nouveaux). Des acétogénines et une styryl-lactone ont été isolées des Annonaceae. Les études phytochimiques d'Argophyllum nitidum et de Pittosporum pancheri ont conduit respectivement à l'isolement de dipeptides et de glycosides farnésylés. L'évaluation biologique de ces composés a également été entreprise. L'activité initiallement observée a été retrouvée dans la plupart des molécules isolées. Des relations structures-activités ont aussi été étudiées.In the search for new active compounds, chemical study of four tropical plants has been investigated: two cytotoxic Annonaceae (Disepalum plagioneurum and Richella obtustata), one Escalloniaceae, which inhibit acetylcholinesterase (Argophyllum nitidum) and one Pittosporaceae which is a MCH1 inhibitor (Pittosporum pancheri). Bioguided fractionation of these plants and chemical transformation of some isolated molecules led to the structural determination of 17 compounds (13 are new). Acetogenins and one styryl-lactone have been isolated from Annonaceae, dipeptides from Argophyllum nitidum and farnesyled glycosides from Pittosporum pancheri. Biological evaluation of isolated compounds have been investigated. Most of these compounds are responsible of the initial activity observed. Structure-activity relationships have also been studied.PARIS-Museum Hist.Naturelle (751052304) / SudocSudocFranceF

Supercritical CO2 extraction of solid-state cultivation fungus producing azaphilone polyketides

Supercritical Fluid Extraction (SFE) methods dedicated to microorganisms specialized metabolites are very scarce in the literature and limited to liquid cultivation. We proposed here a new sample preparation method to achieve SFE of specialized metabolites from solid-state cultivation. SFE parameters, including CO2 pressure, temperature of extraction cell and percentage of co-solvent, were optimized in the case of solid-state cultures of Penicillium sclerotiorum SNB-CN111, a filamentous fungus producing azaphilone pigments. The metabolic composition of the extracts was then analyzed by reverse-phase liquid chromatography coupled to electrospray ionization and tandem mass spectrometry in data dependent acquisition mode. The resulting molecular networks generated by MetGem software allowed the annotation of the extracted metabolites in the different conditions, confirming the enrichment of fractions according to the polarity of azaphilone subfamilies. First, the 100 % CO2 fraction a yield ten times higher than hexane maceration The optimization of SFE method led to an extraction yield twice as high as ethyl acetate maceration when mixing CO2 with ethanol and, indicating that CO2/ethanol SFE is more environmentally-friendly and efficient than standard maceration methods for the extraction of azaphilones from solid-state fermentation

The Search for Antifungals from Amazonian Trees: A Bio-Inspired Screening

International audienceThe anti-fungal activity of 60 extracts from 15 tree species in the French Guiana rainforest against human and wood-rotting fungi was studied. In this way (+)-mopanol (1) was isolated from the ethyl acetate extract of Peltogyne sp. (Caesalpiniaceae) wood. This work demonstrated that (1) the natural durability of wood can indeed guide the search for antifungal agents, (2) that extracts selected in this bio-inspired process exhibit a broad spectrum of antifungal activity and (3) that the method allows for the isolation of strongly active antifungals