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Annals of Botany | 2013

The tannosome is an organelle forming condensed tannins in the chlorophyllous organs of Tracheophyta

Jean Marc Brillouet; Charles Romieu; Benoît Schoefs; Katalin Solymosi; Véronique Cheynier; Hélène Fulcrand; Jean Luc Verdeil; Geneviève Conéjéro

BACKGROUND AND AIMSnCondensed tannins (also called proanthocyanidins) are widespread polymers of catechins and are essential for the defence mechanisms of vascular plants (Tracheophyta). A large body of evidence argues for the synthesis of monomeric epicatechin on the cytosolic face of the endoplasmic reticulum and its transport to the vacuole, although the site of its polymerization into tannins remains to be elucidated. The aim of the study was to re-examine the cellular frame of tannin polymerization in various representatives of the Tracheophyta.nnnMETHODSnLight microscopy epifluorescence, confocal microscopy, transmission electron microscopy (TEM), chemical analysis of tannins following cell fractionation, and immunocytochemistry were used as independent methods on tannin-rich samples from various organs from Cycadophyta, Ginkgophyta, Equisetophyta, Pteridophyta, Coniferophyta and Magnoliophyta. Tissues were fixed in a caffeine-glutaraldehyde mixture and examined by TEM. Other fresh samples were incubated with primary antibodies against proteins from both chloroplastic envelopes and a thylakoidal chlorophyll-carrying protein; they were also incubated with gelatin-Oregon Green, a fluorescent marker of condensed tannins. Coupled spectral analyses of chlorophyll and tannins were carried out by confocal microscopy on fresh tissues and tannin-rich accretions obtained through cell fractionation; chemical analyses of tannins and chlorophylls were also performed on the accretions.nnnKEY RESULTS AND CONCLUSIONSnThe presence of the three different chloroplast membranes inside vacuolar accretions that constitute the typical form of tannin storage in vascular plants was established in fresh tissues as well as in purified organelles, using several independent methods. Tannins are polymerized in a new chloroplast-derived organelle, the tannosome. These are formed by pearling of the thylakoids into 30 nm spheres, which are then encapsulated in a tannosome shuttle formed by budding from the chloroplast and bound by a membrane resulting from the fusion of both chloroplast envelopes. The shuttle conveys numerous tannosomes through the cytoplasm towards the vacuole in which it is then incorporated by invagination of the tonoplast. Finally, shuttles bound by a portion of tonoplast aggregate into tannin accretions which are stored in the vacuole. Polymerization of tannins occurs inside the tannosome regardless of the compartment being crossed. A complete sequence of events apparently valid in all studied Tracheophyta is described.


Reference Module in Chemistry, Molecular Sciences and Chemical Engineering#R##N#Comprehensive Natural Products II#R##N#Chemistry and Biology | 2010

Chemistry of Wine

Véronique Cheynier; Rémi Schneider; Jean-Michel Salmon; Hélène Fulcrand

Wines are alcoholic drinks obtained from the fermentation of grapes. Their composition is determined by the composition of the grape, which depends on genetic characters, vine growing conditions, and grape ripeness at harvest, and by wine-making practices, which involve a series of successive operations, the sequence of which varies considerably depending on the wine type. In white wine making, the first step (usually after crushing) is pressing. This separates the solid parts (i.e., skins, seeds, and eventually stems) from the juice, and the juice is then fermented separately. In red wine making, fermentation is achieved on the whole must obtained after crushing, and pressing is performed only after the maceration phase. Maceration enables extraction of constituents present in the skins and seeds into the fermenting must, including not only the red pigments, but also tannins, volatile compounds and aroma precursors, and plant cell wall polysaccharides. Changes taking place during winemaking involve both biochemical and chemical processes. The former result from yeast and bacterial metabolism during alcoholic and malolactic fermentation, and from the action of various enzymes originating from grape, yeast, and other microorganisms, or added as process aids. Biochemical processes take place mostly in the early stages of the process, while chemical reactions continue throughout wine aging. Composition changes due to yeast and bacterial primary metabolism, the chemistry of aroma compounds, and the chemistry of phenolic compounds in wine are reviewed.


Green Chemistry | 2013

Depolymerisation of condensed tannins in ethanol as a gateway to biosourced phenolic synthons.

Laurent Roumeas; Chahinez Aouf; Eric Dubreucq; Hélène Fulcrand

Plant polyphenols are potential sources of substitutes for phenolic petrochemicals, such as bisphenol A. Among them, condensed tannins are the most abundant after lignins in terrestrial plants. They are especially encountered in agro-industrial residues (i.e. fruit marc) and unprocessed biomass (i.e. barks, needles, and leaves). However, this class of biopolymers requires a depolymerisation step prior to their industrial use as fine chemicals. In this work, phenolic synthons were produced by depolymerisation of an industrial grape seed extract of condensed tannins at the multigram scale. The optimization of the depolymerisation reaction through the selection of the most suitable solvent, nucleophilic agent and temperature allowed the reaction to be carried out at mild temperature (40 °C), in two hours, using ethanol as a solvent. The isolation of compounds of interest was performed by precipitation in ethyl acetate followed by a simple adsorption/desorption step on a polyamide cartridge using ethanol as an eluent.


Food Chemistry | 2019

Monitoring anthocyanin degradation in Hibiscus sabdariffa extracts with multi-curve resolution on spectral measurement during storage

Nawel Achir; André Mundombe Sinela; Christian Mertz; Hélène Fulcrand; Manuel Dornier

This study aims to monitor composition changes in an anthocyanin-rich beverage during storage by the means of UV-VIS measurements associated with a multi-curve resolution procedure. Hibiscus sabdariffa extract was stored at 37u202f°C for 50u202fdays and UV-VIS spectra were measured on the extract and the fractions of the extract every 5u202fdays. MCR was carried out in two steps, first with the fraction and then the extract spectra. The results enabled the main polyphenols initially present to be identified, anthocyanins and chlorogenic acid, but also found the nature of the main degradation products: the polymers from anthocyanin condensation and scission products. In addition, comparison with HPLC analysis results showed that the MCR procedure recovered the correct shapes of the concentration profiles particularly of anthocyanin and polymer kinetics during storage. This work gives perspective for the use of a rapid and efficient technique to monitor pigment-rich beverage processing or storage.


Archive | 1998

Phenolic Composition as Related to Red Wine Flavor

Véronique Cheynier; Hélène Fulcrand; F. Brossaud; Christian Asselin; Michel Moutounet


European Polymer Journal | 2014

Tara tannins as phenolic precursors of thermosetting epoxy resins

Chahinez Aouf; Sofia Benyahya; Antoine Esnouf; Sylvain Caillol; Bernard Boutevin; Hélène Fulcrand


ACS symposium series | 2004

The fate of anthocyanins in wine: Are there determining factors?

Hélène Fulcrand; Vessela Atanasova; Erika Salas; Véronique Cheynier


Archive | 1995

Reactions of Enzymically Generated Quinones in Relation to Browning in Grape Musts and Wines

Véronique Cheynier; Hélène Fulcrand; Sylvain Guyot; Jan Oszmiański; Michel Moutounet


Enología : fundamentos científicos y tecnológicos, 2000, ISBN 84-89922-19-5, págs. 369-376 | 2000

Oxidación de los polifenoles en los mostos y los vinos

Véronique Cheynier; Hélène Fulcrand


Phenolics and estraction : proceedings, Adelaide, 9 october 1997, 1998, ISBN 0-9586839-5-6, págs. 12-17 | 1998

Progress in phenolic Chemistry in the last ten years

Véronique Cheynier; Michel Moutounet; Hélène Fulcrand; Pascale Sarni-Manchado

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Sylvain Caillol

École nationale supérieure de chimie de Montpellier

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Bernard Boutevin

École Normale Supérieure

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Chahinez Aouf

Institut national de la recherche agronomique

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Michel Moutounet

Institut national de la recherche agronomique

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Carine Burguiere

École nationale supérieure de chimie de Montpellier

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Sylvie Rapior

University of Montpellier

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