Publications by authors named "Pierre Waffo-Teguo"

52 Publications

Untargeted LC-HRMS profiling followed by targeted fractionation to discover new taste-active compounds in spirits.

Food Chem 2021 Oct 20;359:129825. Epub 2021 Apr 20.

Univ. Bordeaux, Unité de Recherche Œnologie, EA 4577, USC 1366 INRA, ISVV, 33882 Villenave d'Ornon Cedex, France. Electronic address:

Taste is a key driver of food and beverage acceptability due to its role in consumers' pleasure. The great interest that natural food and beverages now arouse lies notably in the complexity of their taste, which in turn is related to a wide range of taste-active compounds. Going beyond the classic divide between targeted and untargeted strategies, an integrative methodology to spirits was applied. Untargeted profiling of several cognac spirits was implemented by LC-HRMS to identify compounds of interest among hundreds of ions. A targeted fractionation protocol was then developed. By using HRMS and NMR, dihydrodehydrodiconiferyl alcohol was identified and described for the first time in spirits and oak wood. It was characterized as sweet at 2 mg/L in two matrices and was quantified in spirits up to 4 mg/L. These findings demonstrated how this methodology is relevant and effective to discover new taste-active compounds.
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http://dx.doi.org/10.1016/j.foodchem.2021.129825DOI Listing
October 2021

Understanding sweetness of dry wines: First evidence of astilbin isomers in red wines and quantitation in a one-century range of vintages.

Food Chem 2021 Aug 15;352:129293. Epub 2021 Feb 15.

Univ. de Bordeaux, ISVV, EA 5477, Unité de recherche ŒNOLOGIE, USC 1366 INRA, F-33882 Villenave d'Ornon, France. Electronic address:

Astilbin (2R, 3R) was recently reported to contribute to wine sweetness. As its aglycon contains two stereogenic centers, three other stereoisomers may be present: neoisoastilbin (2S, 3R), isoastilbin (2R, 3S), and neoastilbin (2S, 3S). This work aimed at assaying their presence for the first time in wines as well as their taste properties. The isomers were synthesized from astilbin and purified by semi-preparative HPLC. With the four stereoisomers, a sweet taste was perceived whose intensity varied with the configuration. Their content was assayed by developing a UHPLC-Q-Exactive method. The method was applied to screen astilbin and isomers in various wines, especially in different vintages from the same estate. While young wines contained higher concentrations of astilbin than the old ones, the concentrations of the other isomers, mainly neoastilbin, were higher in the old wines, suggesting their formation over time.
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http://dx.doi.org/10.1016/j.foodchem.2021.129293DOI Listing
August 2021

Screening of Wood/Forest and Vine By-Products as Sources of New Drugs for Sustainable Strategies to Control and the Production of Mycotoxins.

Molecules 2021 Jan 14;26(2). Epub 2021 Jan 14.

INRAE, UR1264 Mycology and Food Safety (MycSA), F-33882 Villenave d'Ornon, France.

is a fungal pathogen that can colonize small-grain cereals and maize and secrete type B trichothecene (TCTB) mycotoxins. The development of environmental-friendly strategies guaranteeing the safety of food and feed is a key challenge facing agriculture today. One of these strategies lies on the promising capacity of products issued from natural sources to counteract crop pests. In this work, the in vitro efficiency of sixteen extracts obtained from eight natural sources using subcritical water extraction at two temperatures was assessed against fungal growth and TCTB production by . Maritime pine sawdust extract was shown to be extremely efficient, leading to a significant inhibition of up to 89% of the fungal growth and up to 65% reduction of the mycotoxin production by . Liquid chromatography/mass spectrometry analysis of this active extract revealed the presence of three families of phenolics with a predominance of methylated compounds and suggested that the abundance of methylated structures, and therefore of hydrophobic compounds, could be a primary factor underpinning the activity of the maritime pine sawdust extract. Altogether, our data support that wood/forest by-products could be promising sources of bioactive compounds for controlling and its production of mycotoxins.
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http://dx.doi.org/10.3390/molecules26020405DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7830912PMC
January 2021

Characterization of Stilbene Composition in Grape Berries from Wild Species in Year-To-Year Harvest.

J Agric Food Chem 2020 Nov 5;68(47):13408-13417. Epub 2020 Nov 5.

Université de Bordeaux, Unité de recherche Œnologie, EA 4577, USC 1366 INRAE, ISVV, F-33882 Villenave d'Ornon, France.

Asian and American species possess a strong potential for crossbreeding programs, owing to their several resistance properties. Stilbenes are phenolic compounds present in grape berries and are well-known for their main role as phytoalexins and resistance to biotic stresses in plants. However, their identification and quantification in grape berries from wild remains unexplored. A mass spectrometry multiple reaction monitoring method combined with the analysis of pure standards allowed for the unambiguous characterization of 20 stilbenes in the grape berry skin extracts of nine native species and one cultivated species (cv. Cabernet Sauvignon). A main occurrence of monomeric (-piceid, -piceid, -isorhapontin, and -astringin), dimeric (-ε-viniferin, -ε-viniferin, and pallidol), and oligomeric (isohopeaphenol and r-viniferin) stilbenes was highlighted. Some stilbenes were clearly characterized for the first time in grape berries, such as the dimers ampelopsin A, -vitisinol C, and parthenocissin A as well as the tetramers r2-viniferin and r-viniferin. Stilbene composition and content varied widely among several species and vintage years.
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http://dx.doi.org/10.1021/acs.jafc.0c04907DOI Listing
November 2020

Promote a new paradigm to prevent neurodegenerative disease in sub-Saharan Africa.

Pan Afr Med J 2020;36:138. Epub 2020 Jun 29.

Université de Guadeloupe, Centre Hospitalier Universitaire de Pointe-à-Pitre, Les Abymes, France.

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http://dx.doi.org/10.11604/pamj.2020.36.138.21881DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7422750PMC
March 2021

Anti-tyrosinase, anti-cholinesterase and cytotoxic activities of extracts and phytochemicals from the Tunisian Citharexylum spinosum L.: Molecular docking and SAR analysis.

Bioorg Chem 2020 09 14;102:104093. Epub 2020 Jul 14.

Laboratoire de Chimie Hétérocyclique, Produits Naturels et Réactivité (LR11ES39), Equipe: Chimie Médicinale et Produits Naturels, Faculté des Sciences de Monastir, Université de Monastir, Avenue de l'environnement, 5019 Monastir, Tunisia. Electronic address:

Previously phytochemical investigations carried out on the flowers and trunk bark extracts of Citharexylum spinosum L. tree, allowed the isolation of twenty molecules belonging to several families of natural substances [triterpene acids, iridoid glycosides, phenylethanoid glycosides, 8,3'-neolignan glycosides, together with other phenolic compounds]. In the present work, a biological evaluation (anti-tyrosinase, anticholinesterase and cytotoxic activities) was performed on the prepared extracts and the isolated secondary metabolites. The results showed that the EtOAc extract of the trunk bark displayed the highest anti-tyrosinase effect with a percent inhibition of 55.0 ± 1.8% at a concentration of 100 µg/mL. The highest anticholinesterase activity was presented by the same extract with an IC value of 99.97 ± 3.01 µg/mL. The EtOAc extract of flowers and that of the trunk bark displayed the best cytotoxic property with IC values of 96.00 ± 2.85 and 88.75 ± 2.00 µg/mL, respectively, against the human cervical cancer cell line (HeLa), and IC values of 188.23 ± 3.88 and 197.00 ± 4.25 µg/mL, respectively, against the human lung cancer (A549) cell lines. Biological investigation of the pure compounds showed that the two 8,3'-neolignan glycosides, plucheosides D-D, generate the highest anti-tyrosinase potency with a percent inhibition of 61.4 ± 2.0 and 79.5 ± 2.3%, respectively, at a concentration of 100 µM. The iridoid glycosides exhibited a significant anticholinesterase activity with IC values ranging from 17.19 ± 1.02 to 52.24 ± 2.50 µM. Triterpene pentacyclic acids and iridoid glycosides exerted encouraging cytotoxic effects against HeLa with IC values ranging from 9.00 ± 1.10 to 25.00 ± 1.00 µM. The study of the structure-activity relationship (SAR) has been sufficiently and widely discussed. The natural compounds that exhibited the significant bioactivities were docked.
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http://dx.doi.org/10.1016/j.bioorg.2020.104093DOI Listing
September 2020

Isolation of Taste-Active Triterpenoids from : Sensory Assessment and Identification in Wines and Spirit.

J Nat Prod 2020 05 28;83(5):1611-1622. Epub 2020 Apr 28.

Univ. Bordeaux, ISVV, Unité de Recherche Œnologie, EA 4577, USC 1366 INRA, ISVV, 33882 Villenave d'Ornon Cedex, France.

Six new triterpenoids (-), two known genins ( and ), and five known functionalized triterpenoids (-) were isolated from a heartwood extract. The purification protocol was guided by LC-HRMS by searching for structural analogues of bartogenic acid on the basis of their putative empirical formula. The structures of the new compounds were unequivocally elucidated using HRESIMS and 1D/2D NMR experiments. Sensory analyses were performed in water and in a non-oaked white wine on the pure compounds - at 5 mg/L. All molecules were perceived as bitter in water and wine, but they were mostly reported as modifying the wine taste balance. Using LC-HRMS, compounds - were observed in oaked red wine and cognac and were semiquantified in oak wood extracts. The influence of two cooperage parameters, oak species and toasting process, on compounds - content was studied. All compounds were found in quantities significantly higher in pedunculate than in sessile oak wood. Toasting is a key step in barrel manufacture and modulates the concentration of the discussed compounds. Significantly higher quantities were observed in untoasted wood compared to medium or highly toasted wood. These findings provide new insights into the molecular origin of taste changes due to oak aging.
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http://dx.doi.org/10.1021/acs.jnatprod.0c00106DOI Listing
May 2020

Separation and isolation of major polyphenols from maritime pine (Pinus pinaster) knots by two-step centrifugal partition chromatography monitored by LC-MS and NMR spectroscopy.

J Sep Sci 2020 Mar 16;43(6):1080-1088. Epub 2020 Feb 16.

Unité de recherche Œnologie, Axe Molécules d'Intérêt Biologique, EA 4577, USC 1366 INRA, ISVV, Université de Bordeaux, 33882, Villenave-d'Ornon, France.

Pine knots are a rich source of lignans, flavonoids, and stilbenes. These bioactive compounds are widely known for their roles to combat human disorders but also to protect plants against pathogens. In order to gain knowledge inside their potential activities, a suitable isolation and purification of these high-added value compounds is required. To this end, centrifugal partition chromatography, as a rapid and useful methodology of separation, was employed and developed. The coefficient partition values (K ) of six major compounds in nine biphasic solvent systems were determined to evaluate the most appropriate system. Two-step centrifugal partition chromatography was required to separate lignans using ARIZONA system K (n-heptane/ethyl acetate/methanol/water 1:2:1:2, v:v) and to isolate stilbenes and flavonoids using ARIZONA system P (n-heptane/ethyl acetate/methanol/water 6:5:6:5, v:v). Eight one-compound enriched-fractions were obtained as follows: nortrachelogenin (70.1%), secoisolariciresinol (53.7%), isolariciresinol (61.1%), taxifolin (48.4%), pinocembrin (91.3%), pinobanksin (91.1%), pinosylvin (91.4%), and pinosylvin monomethyl ether (91.1%). Additionally, the centrifugal partition chromatography allowed to unravel the composition of pine knot owing to the several fractions generated. Twenty-two compounds were characterized by liquid chromatography-mass spectrometry and NMR spectroscopy, some of which are described for the first time in literature.
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http://dx.doi.org/10.1002/jssc.201901066DOI Listing
March 2020

New glucosyloxybenzyl 2R-benzylmalate derivatives from the undergrounds parts of Arundina graminifolia (Orchidaceae).

Fitoterapia 2019 Jun 4;135:33-43. Epub 2019 Apr 4.

Strasbourg University, Faculty of Pharmacy, UMR 7200, 67400 Illkirch-Graffenstaden, France.

Phytochemical investigation of the underground part of the blossoming tropical orchid Arundina graminifolia led to the isolation of six new glucosyloxybenzyl 2R-benzylmalate derivatives named arundinosides L-Q (1-6) together with 5 known compounds arundinosides D-F, J and K (7-11). The structures of the isolated compounds were determined by extensive spectroscopic data analysis. The anti-α-glucosidase and antioxidant activities of the isolated compounds were determined. The result indicated that compounds 4-6 and 9 showed moderate to weak α-glucosidase inhibitory effects as well as moderate antioxidant effect.
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http://dx.doi.org/10.1016/j.fitote.2019.03.030DOI Listing
June 2019

Triterpenoids from Quercus petraea: Identification in Wines and Spirits and Sensory Assessment.

J Nat Prod 2019 02 28;82(2):265-275. Epub 2019 Jan 28.

Univ. Bordeaux , Unité de Recherche Oenologie, EA 4577, USC 1366 INRA, ISVV, 33882 Villenave d'Ornon Cedex , France.

Eight new triterpenoids (1-8), the known genin (9), and two known functionalized triterpenoids (10 and 11) were isolated from a Quercus petraea heartwood extract. The structures of the new compounds were unequivocally elucidated using HRESIMS and 1D/2D NMR experiments. Sensory analyses were performed in a non-oaked wine on the pure compounds 1-11. Except compounds 1 and 11, all molecules exhibited a sweet taste at 5 mg/L that was particularly intense for compounds 3 and 9. Using LC-HRMS, compounds 1-11 were observed in an oak wood extract and in oaked red wine and cognac. They were also semiquantified in several samples of sessile ( Q. petraea) and pedunculate ( Q. robur) oak wood extract. All compounds were found in quantities significantly higher in sessile than in pedunculate oak wood. These results support the hypothesis of their contribution to the increase in sweetness during oak aging and show that they can be used as chemical markers to identify the species of oak used for cooperage.
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http://dx.doi.org/10.1021/acs.jnatprod.8b00682DOI Listing
February 2019

Wood and roots of major grapevine cultivars and rootstocks: A comparative analysis of stilbenes by UHPLC-DAD-MS/MS and NMR.

Phytochem Anal 2019 May 15;30(3):320-331. Epub 2019 Jan 15.

Faculté des Sciences Pharmaceutiques, Unité de Recherche Œnologie, EA 4577, USC 1366 INRA, Equipe Molécules d'Intérêt Biologique - ISVV, Univ. Bordeaux, 33882, Villenave d'Ornon cedex, France.

Introduction: Grapevine wood and roots are by-products obtained during vineyard management. This plentiful biomass is known to be rich in stilbenes and can be used as a source of high-value compounds as well as active natural extracts. However, the stilbenes in grapevine wood and roots from different cultivars and rootstocks remain to be characterized.

Objective: The present study investigated the stilbene content of eight major Vitis vinifera cultivars and six different rootstocks. In addition, the distribution of stilbenes was established for each of seven parts into which the plants were sub-divided.

Methodology: For stilbene characterization and quantification purposes, an ultra-high performance liquid chromatography-diode array detector-mass spectrometry (UHPLC-DAD-MS/MS) analysis of different samples was carried out. Moreover, structural data of stilbenes was unambiguously studied by nuclear magnetic resonance (NMR) spectra.

Results: Whatever the cultivar/rootstock combination, stilbenes were found to be oligomerized from the aerial part to the root system. Furthermore, stilbene content varied widely depending on the cultivars and rootstocks. For instance, the cultivars Merlot, Tannat and Gamay noir were the richest in stilbenes while the rootstocks Gravesac, Fercal and 3390C contained the highest amounts.

Conclusion: These findings provide insight into the knowledge that major grapevine cultivars and rootstocks can be used as a potential source of complex stilbenes.
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http://dx.doi.org/10.1002/pca.2815DOI Listing
May 2019

Taste-guided isolation of sweet-tasting compounds from grape seeds, structural elucidation and identification in wines.

Food Chem 2019 Jan 18;272:388-395. Epub 2018 Aug 18.

Univ de Bordeaux, ISVV, EA 4577, Unité de recherche OENOLOGIE, F-33882 Villenave d'Ornon, France; INRA, ISVV, USC 1366 OENOLOGIE, F-33882 Villenave d'Ornon, France. Electronic address:

This work aimed at improving knowledge about sweetness in dry wines. Following on from the empirical observations of winegrowers, we assessed the contribution of grape seeds to wine sensory properties. An inductive fractionation method guided by gustatometry was used to isolate and characterize sweet-tasting compounds from grapes. Fractionation of grape seed macerates was achieved by liquid-liquid extraction, centrifugal partition chromatography (CPC) and preparative HPLC. Then, the structures of the purified compounds were elucidated by use of FTMS and NMR. Five compounds were identified: two new compounds, 2-hydroxy-3-methylpentanoic-2-O-β-glucopyranoside (H3MP-G) and 2-hydroxy-4-methylpentanoic-2-O-β-glucopyranoside acids (H4MP-G), along with gallic-4-O-β-glucopyranoside acid (AG-G), 3-indolyl-(2R)-O-β-d-glycoside lactic acid (ILA-G) and epi-DPA-3'-O-β-glucopyranoside acid (epi-DPA-G). These compounds exhibited various levels of sweetness in a hydro-ethanolic solution and in white and red wines. Additionally, H3MP-G, H4MP-G and epi-DPA-G were identified for the first time in grapes and wines, whereas AG-G has already been reported in white grapes but never in wine.
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http://dx.doi.org/10.1016/j.foodchem.2018.08.070DOI Listing
January 2019

First evidence of epicatechin vanillate in grape seed and red wine.

Food Chem 2018 Sep 30;259:304-310. Epub 2018 Mar 30.

Univ. de Bordeaux, Unité de recherche OENOLOGIE, EA 4577, USC 1366 INRA, ISVV, 33882 Villenave d'Ornon cedex, France. Electronic address:

Flavan-3-ols are units incorporating condensed tannin, which are widely present in grape and wine. They play a considerable role in wine sensory perception such as astringency, bitterness and mouth-feel. In grape and wine, the flavan-3-ols reported to date are (epi)catechin, (epi)gallocatechin, (epi)gallocatechin gallate and (epi)catechin glycoside. This study now shows the presence of a new flavan-3-ol epicatechin vanillate in grape seed and red wine. A putative unknown flavan-3-ol derived from grape seed was targeted by LC-HRMS/MS. Fractionation and purification by centrifugal partition chromatography and Prep HPLC allowed us to obtain the pure new flavan-3-ol. NMR and HRMS data revealed this compound to be epicatechin-3-O-vanillate. Quantification analysis results showed that epicatechin vanillate present in grape seed and red wine in the μg/g dry seed and the μg/L concentration range, respectively.
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http://dx.doi.org/10.1016/j.foodchem.2018.03.134DOI Listing
September 2018

New insight into the unresolved HPLC broad peak of Cabernet Sauvignon grape seed polymeric tannins by combining CPC and Q-ToF approaches.

Food Chem 2018 May 2;249:168-175. Epub 2018 Jan 2.

Univ. de Bordeaux, ISVV, EA 4577, Unité De recherche OENOLOGIE, F-33882 Villenave d'Ornon, France; INRA, ISVV, USC 1366 OENOLOGIE, F-33882 Villenave d'Ornon, France. Electronic address:

Polymeric tannins from grapes have always been reported as an unresolved broad peak in HPLC chromatograms, and this has severely limited their identification to date. This study aimed to disassemble this broad peak and explore the polymeric tannin molecules inside. By applying centrifugal partition chromatography (CPC), an efficient separation approach was developed to split the broad peak of grape seed tannins into fractions. Then, the fractions were analyzed by Q-ToF (quadrupole time-of-flight mass spectrometry) to determine the corresponding structures of the tannins. The results suggest that grape seed polymeric tannins were eluted consecutively according to their degree of polymerization (DP). Condensed tannins identified in wine grape seed have a range of DP and degree of galloylation (DG) up to 20 and 11, respectively. The molecular mass of the largest molecule detected was 6067. To our knowledge, this is the first report to offer an insight into the broad peak of polymeric tannins found with HPLC and to characterize the tannins with a DP up to 20 as shown by HRMS and MS/MS data.
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http://dx.doi.org/10.1016/j.foodchem.2018.01.005DOI Listing
May 2018

Phytochemical study of the trunk bark of Citharexylum spinosum L. growing in Tunisia: Isolation and structure elucidation of iridoid glycosides.

Phytochemistry 2018 Feb 22;146:47-55. Epub 2017 Dec 22.

Laboratoire de Chimie Hétérocyclique, Produits Naturels et Réactivité (LR11ES39), Equipe: Chimie Médicinale et Produits Naturels, Faculté des Sciences de Monastir, Université de Monastir, Avenue de l'environnement, 5019 Monastir, Tunisia. Electronic address:

A phytochemical investigation of the trunk bark ethyl acetate extract of Citharexylum spinosum L. has led to the isolation of four previously undescribed iridoid glycosides, tunispinosides A-D, and five known phenylethanoid glycosides, verbascoside, leucosceptoside A, martynoside, isoverbascoside and plantainoside C, together with 4-hydroxy-2,6-dimethoxyphenyl 6'-O-vanilloyl-β-D-glucopyranoside, two 8,3'-neolignan glycosides, plucheosides D-D, coniferyl aldehyde, vanillic acid, syringic acid, ferulic acid and tyrosol. All compounds were isolated for the first time from C. spinosum. Their isolation was carried out using silica gel column and high performance liquid chromatography (HPLC). Structures were established by spectroscopic means including 1D and 2D NMR experiments, and spectrometric ESI-HRMS analysis.
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http://dx.doi.org/10.1016/j.phytochem.2017.11.012DOI Listing
February 2018

Antioxidant and Cytoprotective Activities of Grapevine Stilbenes.

J Agric Food Chem 2017 Jun 7;65(24):4952-4960. Epub 2017 Jun 7.

EA 4577, Unité de Recherche Oenologie, Université Bordeaux, ISVV , F-33882 Villenave d'Ornon, France.

Grapevine stem extracts are viticulture byproducts rich in stilbenes that are increasingly studied for their potential biological activities. This study aimed to investigate some biological activities of a grape byproduct with high stilbenoid content and to point out the molecules responsible of these beneficial activities. As a consequence, the extract was subjected to a bioguided fractionation and separation by centrifugal partition chromatography. The obtained fractions were characterized by liquid chromatography coupled to mass spectrometry and nuclear magnetic resonance. Fractions were purified further by column chromatography and resulted in the purification of the main constituents. Thirteen stilbenes have been quantified. The most abundant compounds were ε-viniferin, resveratrol, and, in lesser amounts, isohopeaphenol and ampelopsin A. The extract, fractions, and major stilbenes were tested for their antioxidant activity by oxygen radical absorbance capacity and their cyprotective effects against β-amyloid on rat pheochromocytoma cells. Among them, fraction 5 showed significant antioxidant activity and fraction 2 had a significant cytoprotective effect against β-amyloid-induced toxicity. Two putative inhibitors of β-amyloid toxicity have been identified: ampelopsin A and piceatannol.
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http://dx.doi.org/10.1021/acs.jafc.7b01254DOI Listing
June 2017

Stilbenes from Vitis vinifera L. Waste: A Sustainable Tool for Controlling Plasmopara Viticola.

J Agric Food Chem 2017 Apr 24;65(13):2711-2718. Epub 2017 Mar 24.

Université de Bordeaux, Faculté des Sciences Pharmaceutiques, Unité de Recherche Œnologie EA 4577, USC 1366 INRA, Equipe Molécules d'Intérêt Biologique (Gesvab), Institut des Sciences de la Vigne et du Vin , CS 50008-210, Chemin de Leysotte, 33882 Villenave d'Ornon, France.

Stilbene-enriched extracts from Vitis vinifera waste (cane, wood, and root) were characterized by UHPLC-MS. Eleven stilbenes were identified and quantified as follows: ampelopsin A, (E)-piceatannol, pallidol, (E)-resveratrol, hopeaphenol, isohopeaphenol, (E)-ε-viniferin, (E)-miyabenol C, (E)-ω-viniferin, r2-viniferin, and r-viniferin. The fungicide concentration inhibiting 50% of growth of Plasmopara viticola sporulation (IC) was determined for the extracts and also for the main compounds isolated. r-Viniferin followed by hopeaphenol and r2-viniferin showed low IC and thus high efficacy against Plasmopara viticola. Regarding stilbene extracts, wood extract followed by root extract showed the highest antifungal activities. These data suggest that stilbene complex mixtures from Vitis vinifera waste could be used as a cheap source of bioactive stilbenes for the development of natural fungicides.
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http://dx.doi.org/10.1021/acs.jafc.7b00241DOI Listing
April 2017

Taste-Guided Isolation of Bitter Lignans from Quercus petraea and Their Identification in Wine.

J Nat Prod 2016 10 29;79(10):2432-2438. Epub 2016 Sep 29.

Université de Bordeaux, ISVV , EA 4577, Unité de Recherche OENOLOGIE, 210 Chemin de Leysotte, CS 50008, 33882 Villenave d'Ornon, France.

Quercoresinosides A and B (1 and 2), two new lignans, were isolated from a toasted Quercus petraea heartwood extract along with a known compound, 3-methoxy-4-hydroxyphenol 1-O-β-d-(6'-O-galloyl)glucopyranoside (3). The purification protocol was based on a taste-guided approach that sought to reveal new bitter compounds released from oak wood into wines and spirits. HRMS and NMR data were used to establish that compounds 1 and 2 are lignan derivatives bearing a glucosyl unit and a galloyl unit at the same positions. Hydrolysis of these compounds showed that they could be distinguished by the absolute configuration of their respective lyoniresinol genin as determined by chiral LC-HRMS in comparison with (+)- and (-)-lyoniresinol standards. Sensory analyses were performed in a non-oaked wine on the pure compounds 1-3. The three molecules exhibited a bitter taste at 2 mg/L that was particularly intense for compounds 2 and 3. Finally, LC-HRMS demonstrated the occurrence of compounds 1-3 in oaked wine and brandy, which supports the hypothesis of their contributions to the increase in bitterness during oak aging.
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http://dx.doi.org/10.1021/acs.jnatprod.6b00142DOI Listing
October 2016

Hyphenating Centrifugal Partition Chromatography with Nuclear Magnetic Resonance through Automated Solid Phase Extraction.

Anal Chem 2016 10 29;88(20):9941-9948. Epub 2016 Sep 29.

Université Bordeaux , Faculté des Sciences Pharmaceutiques, ISVV, EA 4577 Œnologie, Molécules d'Intérêt Biologique (GESVAB), F-33882 Villenave-d'Ornon, France.

Centrifugal partition chromatography (CPC) and all countercurrent separation apparatus provide chemists with efficient ways to work with complex matrixes, especially in the domain of natural products. However, despite the great advances provided by these techniques, more efficient ways of analyzing the output flow would bring further enhancement. This study describe a hyphenated approach made by coupling NMR with CPC through a hybrid-indirect coupling made possible by using a solid phase extraction (SPE) apparatus intended for high-pressure liquid chromatography (HPLC)-NMR hyphenation. Some hardware changes were needed to adapt the incompatible flow-rates and a reverse-engineering approach that led to the specific software required to control the apparatus. 1D HNMR and H-H correlation spectroscopy (COSY) spectra were acquired in reasonable time without the need for any solvent-suppression method thanks to the SPE nitrogen drying step. The reduced usage of expensive deuterated solvents from several hundreds of milliliters to the milliliter order is the major improvement of this approach compared to the previously published ones.
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http://dx.doi.org/10.1021/acs.analchem.6b01429DOI Listing
October 2016

Chemical Affinity between Tannin Size and Salivary Protein Binding Abilities: Implications for Wine Astringency.

PLoS One 2016 12;11(8):e0161095. Epub 2016 Aug 12.

Univ. de Bordeaux, ISVV, EA 4577, Unité de recherche OENOLOGIE, F-33882, Villenave d'Ornon, France.

Astringency perception, as an essential parameter for high-quality red wine, is principally elicited by condensed tannins in diversified chemical structures. Condensed tannins, which are also known as proanthocyanidins (PAs), belong to the flavonoid class of polyphenols and are incorporated by multiple flavan-3-ols units according to their degree of polymerization (DP). However, the influence of DP size of PAs on astringency perception remains unclear for decades. This controversy was mainly attributed to the lack of efficient strategies to isolate the PAs in non-galloylated forms and with individual degree size from grape/wine. In the present study, the astringency intensity of purified and identified grape oligomeric tannins (DP ranged from 1 to 5) was firstly explored. A novel non-solid phase strategy was used to rapidly exclude the galloylated PAs from the non-galloylated PAs and fractionate the latter according to their DP size. Then, a series of PAs with individual DP size and galloylation were purified by an approach of preparative hydrophilic interaction chromatography. Furthermore, purified compounds were identified by both normal phase HPLC-FLD and reverse phase UHPLC-ESI-Q-TOF. Finally, the contribution of the astringency perception of the individual purified tannins was examined with a salivary protein binding ability test. The results were observed by HPLC-FLD and quantified by changes in PA concentration remaining in the filtrate. In summary, a new approach without a solid stationary phase was developed to isolate PAs according to their DP size. And a positive relationship between the DP of PAs and salivary protein affinity was revealed.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0161095PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4982662PMC
August 2017

How stereochemistry influences the taste of wine: Isolation, characterization and sensory evaluation of lyoniresinol stereoisomers.

Anal Chim Acta 2015 Aug 10;888:191-8. Epub 2015 Aug 10.

Université de Bordeaux, ISVV, EA 4577, Unité de recherche OENOLOGIE, F-33882 Villenave d'Ornon, France; INRA, ISVV, USC 1366 OENOLOGIE, 33882 Villenave d'Ornon, France. Electronic address:

Wine expresses its beauty by sending a sensory message to the taster through molecules coming from grapes, yeast metabolism or oak wood. Among the compounds released during barrel aging, lyoniresinol has been recently reported as a relevant contributor to wine bitterness. As this lignan contains three stereogenic carbons, this work aimed at investigating the influence of stereochemistry on wine taste by combining analytical and sensorial techniques. First, an oak wood extract was screened by Liquid Chromatography-High Resolution Mass Spectrometry to target isomers separable in a symmetric environment and a diastereoisomer called epi-lyoniresinol was isolated for the first time. Then, an original racemic resolution based on natural xylose-derivatives was carried out to obtain lyoniresinol enantiomers. Chiroptical spectroscopic measurements associated with theoretical calculations allowed the unambiguous determination of their absolute configuration. The taste properties of all these stereoisomers revealed that only one lyoniresinol enantiomer is strongly bitter whereas the other one is tasteless and the diastereoisomer is slightly sweet. The presence of these three compounds was established in an oaked Bordeaux wine by chiral and non-chiral chromatography, suggesting the significant influence of stereochemistry on wine taste.
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http://dx.doi.org/10.1016/j.aca.2015.06.061DOI Listing
August 2015

Isolation and structure elucidation of bioactive compounds from the roots of the Tunisian Ononis angustissima L.

Bioorg Med Chem Lett 2015 Sep 26;25(18):3825-30. Epub 2015 Jul 26.

Laboratory of Heterocyclic Chemistry, Natural Products and Reactivity, Team: Medicinal Chemistry and Natural Products, Faculty of Science of Monastir, University of Monastir, Avenue of Environment, 5019 Monastir, Tunisia. Electronic address:

A phytochemical investigation of the roots of Ononis angustissima L. (Fabaceae) offered to the bio-guided isolation of new isoflavone 3-(4-(glucopyranosyloxy)-5-hydroxy-2-methoxyphenyl)-7-hydroxy-4H-chromen-4-one 1, together with nine known compounds, ononin 2, formononetin 3, (+)-puerol A-2'-O-β-D-glucose 4, (-)-puerol B-2'-O-β-D-glucopyranose ((-)-sophoraside A) 5, (+)-puerol A 6, (-)-trifolirhizin 7, (-)-trifolirhizin-6'-O-malonate 8, (-)-maackiain 9 and (-)-medicarpin 10. Compounds 2-10 were isolated and identified for the first time in Ononis angustissima. We investigated antioxidant capacities of isolated molecules and results showed that compound 6 exhibited the highest antioxidant activity with IC50 values of 19.53 μg/mL, 28.29 μg/mL and 38.53 μg/mL by DPPH radical, ABTS radical cation and reducing power assay, respectively, and an interesting IC50 (20.45 μg/mL) of 1 against DPPH. In addition, the neuroprotective activity of six isolated molecules (4-7, 9, 10) were evaluated. Following the exposure of PC12 cells to Aβ25-35, compounds 9 and 10 triggered a significant increase of cell viability and in a dose dependent manner.
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http://dx.doi.org/10.1016/j.bmcl.2015.07.076DOI Listing
September 2015

Dual and Opposite Effects of hRAD51 Chemical Modulation on HIV-1 Integration.

Chem Biol 2015 Jun 4;22(6):712-23. Epub 2015 Jun 4.

MFP, UMR5234, CNRS-Université de Bordeaux, SFR Transbiomed, 33076 Bordeaux, France. Electronic address:

The cellular DNA repair hRAD51 protein has been shown to restrict HIV-1 integration both in vitro and in vivo. To investigate its regulatory functions, we performed a pharmacological analysis of the retroviral integration modulation by hRAD51. We found that, in vitro, chemical activation of hRAD51 stimulates its integration inhibitory properties, whereas inhibition of hRAD51 decreases the integration restriction, indicating that the modulation of HIV-1 integration depends on the hRAD51 recombinase activity. Cellular analyses demonstrated that cells exhibiting high hRAD51 levels prior to de novo infection are more resistant to integration. On the other hand, when hRAD51 was activated during integration, cells were more permissive. Altogether, these data establish the functional link between hRAD51 activity and HIV-1 integration. Our results highlight the multiple and opposite effects of the recombinase during integration and provide new insights into the cellular regulation of HIV-1 replication.
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http://dx.doi.org/10.1016/j.chembiol.2015.04.020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4889029PMC
June 2015

Development of an analytical methodology using Fourier transform mass spectrometry to discover new structural analogs of wine natural sweeteners.

Anal Chim Acta 2015 Jan 1;853:425-434. Epub 2014 Nov 1.

Univ. de Bordeaux, ISVV, EA 4577, Unité de recherche OENOLOGIE, F-33882 Villenave d'Ornon, France; INRA, ISVV, USC 1366 OENOLOGIE, 33882 Villenave d'Ornon, France.

Volatile and non-volatile molecules are directly responsible for the thrill and excitement provided by wine-tasting. Their elucidation requires powerful analytical techniques and innovative methodologies. In a recent work, two novel sweet compounds called quercotriterpenosides (QTT) were identified in oak wood used for wine-ageing. The aim of the present study is to discover structural analogs of such natural sweeteners in oak wood. For this purpose, an analytical approach was developed as an alternative to chemical synthesis. Orbitrap mass spectrometry proved to be a crucial technique both to demonstrate the presence of QTT analogs in oak wood by targeted screening and to guide the purification pathway of these molecules using complementary chromatographic tools. Four compounds were isolated and identified for the first time: two isomers, one glucosyl derivative and one galloyl derivative of QTT. Their tasting showed that only the two new isomers were sweet, thus demonstrating both the pertinence of the strategy and the influence of functional groups on gustatory properties. Finally, this paper presents some developments involving multistage Fourier transform mass spectrometry (FTMS) to provide solid structural information on these functional groups prior to any purification of compounds. Such analytical developments could be particularly useful for research on taste-active or bio-active products.
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http://dx.doi.org/10.1016/j.aca.2014.10.039DOI Listing
January 2015

Unambiguous Determination of the Absolute Configuration of Dimeric Stilbene Glucosides from the Rhizomes of Gnetum africanum.

J Nat Prod 2014 Aug;77(8):1981-5

Groupe d'Etude des Substances Végétales à Activité Biologique, EA 3675, Université Bordeaux, ISVV , 210 Chemin de Leysotte, F-33882 Villenave d'Ornon, France.

Dimeric stilbene glucosides 1-3 [two diastereomers of (-)-gnemonoside A (1a and 1b), (-)-gnemonoside C (2), and (-)-gnemonoside D (3)] as well as a mixture of the two enantiomers of gnetin C (4) were isolated from the rhizomes of Gnetum africanum. The two enantiomers of gnetin C, (+)-4 and (-)-4, were obtained from the aglycones of 1a and 1b, respectively. The configurations of these stilbenoids were investigated by NMR and vibrational circular dichroism (VCD) experiments. The absolute configurations of (-)-1a, (-)-2, (-)-3, and (-)-4 were established as 7aS,8aS by VCD spectroscopy in combination with density functional theory calculations. The antiamyloidogenic activity of the isolated stilbenes was also evaluated versus beta-amyloid fibrils. The four glucosides of gnetin C (1a, 1b, 2, and 3) were found to be the most active compounds, with inhibition percentages of 56, 56, 58, and 54 at 10 μM, respectively.
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http://dx.doi.org/10.1021/np500427vDOI Listing
August 2014

Polyphenols from the stems of Morus alba and their inhibitory activity against nitric oxide production by lipopolysaccharide-activated microglia.

Fitoterapia 2014 Sep 7;97:253-60. Epub 2014 Jun 7.

GESVAB EA 3675, ISVV, Université de Bordeaux, F-33882 Villenave d'Ornon Cedex, France.

Neuroinflammatory processes are involved in the pathogenesis of many neurodegenerative disorders. Microglial cells, the main immune cells of the central nervous system, represent a target of interest to search for naturally occurring anti-inflammatory products. In this study, we evaluated the anti-inflammatory properties of polyphenols obtained from the stems of Morus alba. This edible species, known as white mulberry, is frequently studied because of its traditional use in Asian medicine and its richness in different types of polyphenols, some of which are known to be phytoalexins. One new coumarin glycoside, isoscopoletin 6-(6-O-β-apiofuranosyl-β-glucopyranoside) (1) was mainly isolated by CPC (centrifugal partition chromatography) from this plant, together with seven known polyphenols (2-8). Their structures were established on the basis of spectroscopic analyses including extensive 2D NMR studies. The eight isolated compounds were evaluated for their inhibitory activities on nitric oxide (NO) production in lipopolysaccharide (LPS)-induced BV-2 microglial cells. The absence of cell toxicity is checked by a MTT assay.
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http://dx.doi.org/10.1016/j.fitote.2014.06.001DOI Listing
September 2014

Viniphenol A, a complex resveratrol hexamer from Vitis vinifera stalks: structural elucidation and protective effects against amyloid-β-induced toxicity in PC12 cells.

J Nat Prod 2014 Feb 12;77(2):213-7. Epub 2014 Feb 12.

Université de Bordeaux , ISVV, GESVAB, EA 3675, F-33140 Villenave d'Ornon Cedex, France.

Stilbenes have received much attention during the last two decades following the discovery of resveratrol in wine. Since then, there have been a growing number of papers reporting various biological activities of naturally occurring stilbenes. The aim of this study was to determine new minor stilbenes from Vitis vinifera stalks. Purification of these compounds was achieved by means of centrifugal partition chromatography, a versatile separation technique that does not require a solid stationary phase. Viniphenol A (1), a new resveratrol hexamer, was isolated along with five oligostilbenoids identified in V. vinifera for the first time, ampelopsin C, davidiol A, leachianol F, leachianol G, and E-maackin, a dimer with an unusual dioxane moiety, and 14 known hydroxystilbenes. The structure and stereochemistry of viniphenol A were determined on the basis of spectroscopic data analysis and molecular modeling under NMR constraints. Viniphenol A showed protective effects against amyloid-β-induced toxicity in PC12 cell cultures.
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http://dx.doi.org/10.1021/np4005294DOI Listing
February 2014

Natural stilbenoids isolated from grapevine exhibiting inhibitory effects against HIV-1 integrase and eukaryote MOS1 transposase in vitro activities.

PLoS One 2013 28;8(11):e81184. Epub 2013 Nov 28.

Université François Rabelais de Tours, EA 6306, UFR Sciences Pharmaceutiques, Parc Grandmont, Tours, France.

Polynucleotidyl transferases are enzymes involved in several DNA mobility mechanisms in prokaryotes and eukaryotes. Some of them such as retroviral integrases are crucial for pathogenous processes and are therefore good candidates for therapeutic approaches. To identify new therapeutic compounds and new tools for investigating the common functional features of these proteins, we addressed the inhibition properties of natural stilbenoids deriving from resveratrol on two models: the HIV-1 integrase and the eukaryote MOS-1 transposase. Two resveratrol dimers, leachianol F and G, were isolated for the first time in Vitis along with fourteen known stilbenoids: E-resveratrol, E-piceid, E-pterostilbene, E-piceatannol, (+)-E-ε-viniferin, E-ε-viniferinglucoside, E-scirpusin A, quadragularin A, ampelopsin A, pallidol, E-miyabenol C, E-vitisin B, hopeaphenol, and isohopeaphenol and were purified from stalks of Vitis vinifera (Vitaceae), and moracin M from stem bark of Milliciaexelsa (Moraceae). These compounds were tested in in vitro and in vivo assays reproducing the activity of both enzymes. Several molecules presented significant inhibition on both systems. Some of the molecules were found to be active against both proteins while others were specific for one of the two models. Comparison of the differential effects of the molecules suggested that the compounds could target specific intermediate nucleocomplexes of the reactions. Additionally E-pterostilbene was found active on the early lentiviral replication steps in lentiviruses transduced cells. Consequently, in addition to representing new original lead compounds for further modelling of new active agents against HIV-1 integrase, these molecules could be good tools for identifying such reaction intermediates in DNA mobility processes.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0081184PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3842960PMC
December 2014

The antioxidant properties of new dimer and two monomers of phenolic acid amides isolated from Limoniastrum guyonianum.

Food Chem 2014 Mar 25;146:466-71. Epub 2013 Sep 25.

Laboratoire Des Plantes Extrêmophile, Centre de Biotechnologie de Borj Cédria, BP 901, 2050 Hammam-Lif, Tunisia; Univ. Bordeaux2, ISVV, Groupe d'Etude des Substances Végétales à Activité Biologique, EA 3675, F-33882 Villenave d'Ornon, France. Electronic address:

Limoniastramide, a new dimer of phenolic acid amide, isolated from Limoniastrum guyonianum, along with two natural monomers N-E-caffeoyl tyramine (1) and N-E-feruloyl tyramine (2), using centrifugal partition chromatography (CPC). Their structures were determined on the basis of spectroscopic data analysis. We investigate the antioxidant activities of Limoniastrum amides using various in vitro assays. Results showed that N-E-feruloyl tyramine and N-E-caffeoyl tyramine exhibited the highest DPPH scavenging activity compared to the dimer (IC50=0.5, 0.6 and 6.5μg/ml, respectively). In addition, they have significant capacities to inhibit the bleaching of β-carotene. Limoniastramide presented the best activity with an IC50 value equal to 8μg/ml. Finally, the N-E-caffeoyl tyramine showed the highest reducing power (EC50=26μg/ml) compared to the other molecules. The present study found that L. guyonianum amides have effective in vitro antioxidant and radical scavenging activity which can be used in pharmacological and food industry due to their antioxidant properties.
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http://dx.doi.org/10.1016/j.foodchem.2013.09.077DOI Listing
March 2014

Comparative analyses of stilbenoids in canes of major Vitis vinifera L. cultivars.

J Agric Food Chem 2013 Nov 14;61(47):11392-9. Epub 2013 Nov 14.

Univ. de Bordeaux , ISVV, Groupe d'Etude des Substances Végétales à Activité Biologique, EA 3675, F-33140 Villenave d'Ornon, France.

Grapevine canes are rich in resveratrol and its complex derivatives. These compounds have many biological activities and are needed mainly for health purposes. Canes, which are often wasted, can be used to produce these high-value compounds at low cost. We studied sixteen Vitis vinifera L. cultivars among the most widely cultivated ones worldwide. Polyphenols were extracted from their canes and identified by liquid chromatography-nuclear magnetic resonance spectroscopy. We accurately determined the content of E-ε-viniferin, E-resveratrol, E-piceatannol, and vitisin B and, for the first time, that of hopeaphenol and miyabenol C. The canes did not contain these major stilbene compounds in similar proportions, and their abundance and order of abundance varied according to the cultivar. For instance, Pinot noir has very high levels of E-resveratrol and E-ε-viniferin; Gewurztraminer has very high levels of vitisin B, and Carignan and Riesling have very high levels of hopeaphenol. These findings suggest that the right cultivar should be used to obtain the highest yield of a polyphenol of interest.
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http://dx.doi.org/10.1021/jf403716yDOI Listing
November 2013