Resveratrol Metabolites Are Able to Reduce Steatosis in Cultured Hepatocytes

Steatosis is characterized primarily by excessive lipid accumulation in the form of triglycerides in the liver. Although resveratrol shows a low bioavailability, it has significant positive effects on steatosis. The aim of this study was to analyze whether some phase II and microbial resveratrol metabolites (trans-resveratrol-4′-O-glucuronide (R-4G); trans-resveratrol-3-O-glucuronide (R-3G); trans-resveratrol-3-O-sulfate (R-S) and dihydro-resveratrol (DH-R) were effective in reducing hepatocyte fat accumulation. An in vitro model mimicking the hepatocyte situation in fatty liver was developed by incubating mouse AML12 hepatocytes with palmitic acid (PA). For cell treatments, hepatocytes were incubated with 1, 10, or 25 µM resveratrol or its metabolites. Triglycerides and cell viability were assessed using commercial kits. Protein expression of enzymes and transporters involved in triglyceride metabolism were analyzed by western blot. We show for the first time that resveratrol and all the tested metabolites, at 1 µM, partially prevented lipid accumulation induced by the saturated fatty acid PA in AML12 hepatocytes. This effect was mainly due to the inhibition of de novo lipogenesis. This demonstrates that the low bioavailability of resveratrol is not as big a problem as it was thought to be, because resveratrol metabolites contribute to the delipidating effects of the parent compound.This research was funded by Ministerio de Economía y Competitividad-Fondo Europeo de Desarrollo Regional, grant number AGL-2015-65719-R; Instituto de Salud Carlos III CIBERobn, grant number CB12/03/30007; University of the Basque Country, grant number GIU 18/173

Extrapolation des courbes de tarage en crue par modélisation hydraulique (Projet européen Hydrat)

Rating curves extrapolation for flood discharge by hydraulic modelling. The rating curve of a hydrometric station links stage to discharge. Based on gauges, they are extrapolated beyond the higher measured discharge. According to a set of several hundred of French hydrometric stations, more than half of the rating curves have not been gauged more than a two year flood. This paper thus focuses on the extrapolation at high water levels of the stage-discharge relationship by the use of hydraulic modeling and the integration of uncertainties from measurements. An application is presented on a set of southern French rivers.La détermination des courbes de tarage permet la reconstitution des débits au droit d’une section pour une hauteur donnée. Ces courbes sont basées sur l’exploitation de jaugeages et extrapolées au-delà du plus fort débit mesuré. Le bilan sur le degré d’extrapolation des courbes de tarage en France a montré que pour la majorité des 325 stations testées, situées majoritairement sur le bassin RMC, la hauteur maximale jaugée correspond à un débit de période de retour inférieure à 2 ans. La méthode décrite dans cet article vise à extrapoler les courbes de tarage à l’aide de modèles hydrauliques, tout en intégrant l’incertitude sur les mesures de jaugeages. Une application de la méthode sur une sélection de stations hydrométriques du Sud de la France est présentée ici.Pobanz Karine, Renouf Elodie, Sauquet Éric, Lang Michel. Extrapolation des courbes de tarage en crue par modélisation hydraulique (Projet européen Hydrat). In: Mesures Hydrologiques et Incertitudes en Hydrométrie et Qualité de l’eau. Paris, 1 et 2 avril 2008. 2008

Incertitudes sur les débits de crue

L'incertitude sur l'estimation des débits de crue est liée aux erreurs sur la mesure des hauteurs et des débits, et sur l'extrapolation de la courbe de tarage. Les erreurs usuelles constatées sur un jeu de plusieurs centaines de stations hydrométriques françaises sont de l'ordre de 1% sur les hauteurs de crue (± 5 cm), et entre 3 et 5 % pour le jaugeage des débits, avec des erreurs plus fortes lorsque la vitesse d'écoulement ou le gradient de montée des eaux sont très élevés. L'erreur sur les débits de crue (au-delà du plus fort débit jaugé) peut être très importante lorsque l'extrapolation de la courbe de tarage ne respecte pas les propriétés hydrauliques des écoulements (cf. discontinuité de la relation hauteur-débit, avant et après débordement du lit mineur et inondation du lit majeur). L'incertitude finale sur l'estimation des débits obtenue après étude hydraulique est de l'ordre de ± 15% pour un débit voisin de la crue décennale, sauf en cas de configuration hydraulique complexe ou d'absence de débit jaugé en crue. / Uncertainty on flood discharge estimates are linked to errors on flood stage, discharge measurement and rating curve extrapolation. According to a set of several hundred of French hydrometric stations, the standard uncertainties are of the order of 1% (i.e ± 5 cm) on flood water level, and between 3 to 5% on discharge measurement, with larger values when flow velocity or gradient of water raising are important. More than half of the rating curves have not been gauged more than a 2 year flood. Errors on non gauged discharges can be very large when the hydraulic properties of flow are not taken into account (non linear relationship between stage and discharge, discontinuity of flow between main channel and flood plain). The final uncertainty on discharge estimate based on hydraulic extrapolation of the rating curve is about ± 15% for the 10 year flood, except for complex hydraulic situations or without any gauging values

Identification and quantification of stilbenes in some Tunisian red wines using UPLC-MS and HPLC-DAD

Seven Tunisian red wines mainly from the Mornag appellation were analyzed for resveratrol and analogues. The wines of each variety were evaporated, concentrated, and then subjected to fractionation and purification using XAD16 and DOWEX column chromatography. In addition to resveratrol, seven stilbenes were identified by UPLC-MS. The stilbenes derived were shown to be piceatannol, piceid, a-viniferin, e-viniferin, hopeaphenol and isohopeaphenol. From the point of view of the presence of resveratrol derivatives, one wine, Sidi Zahia, was the richest qualitatively

Ind. crops prod.

Currently, one of the biggest challenges in viticulture is to valorize the huge amount of biomass, especially grapevine waste. Subcritical water is a sustainable and eco-friendly method of extraction based on the use of water as an extracting agent, corresponding to the strategy called "green chemistry". Application of a high temperature and a high pressure maintains the water in its liquid form allowing polar and less polar compounds to be extracted. Stilbenes are low-polarity compounds that normally require organic solvents for their extraction. This study investigated the possibility of using a subcritical water process to extract complex stilbenes from three vine co-products: cane, wood, and root. Various temperatures (100, 130, 160 and 190 degrees C) and contact times (5, 15 and 30 min) were tested by accelerated solvent extraction (ASE). The highest stilbene yield was obtained at 160 degrees C and 5 min for cane (3.62 g/kg dry mass), wood (9.32 g/kg dry mass) and root (12.1 g/kg dry mass). ASE allowed the extraction of monomers, dimers, trimers and tetramers of stilbenes in similar amounts as with conventional organic solvents. In addition, the subcritical extraction conditions led to the formation of an uncommon tetrameric stilbene, named vitisin F. The possibility of using "green chemistry" for extracting oligomeric stilbenes is a step forward in the search for alternatives to organic solvents

Isolation of Hydrolyzable Tannins from <i>Castanea sativa</i> Using Centrifugal Partition Chromatography

Castanea sativa wood is a rich source of hydrolyzable tannins, known for their diverse bioactivities. To investigate these bioactive properties further, it is crucial to isolate and characterize hydrophilic compounds effectively. To address this issue, we developed a centrifugal partition chromatography (CPC) method and applied it to an aqueous C. sativa wood extract. We determined the partition coefficients (KD) of the six major compounds using four butanol-/water-based biphasic solvent systems. Initially, we utilized the n-butanol/propanol/water (3:1:4, v/v/v) systems for the first fractionation step. Subsequently, we employed the water/methyl tert-butyl ether/butanol/acetone (8:5:3:4, v/v/v/v) system to fractionate moderately and highly hydrophilic fractions. We calculated the KD values for major compounds of the most hydrophilic fractions using the butanol/ethanol/water (4:1:5, v/v/v) and butanol/isopropanol/water (2:1:3, v/v/v) systems. In total, we isolated 23 compounds through a combination of CPC, size exclusion chromatography, and preparative HPLC. Among these compounds, six have never been previously described. We characterized them by 1D and 2D NMR experiments and high-resolution mass spectroscopy acquisitions

Journal of Food Composition and Analysis

Pistacia lentiscus L. is a shrub of the Anacardiaceae family whose fruits are used in Tunisian and Algerian diets. The phenolic composition at 5 different physiological stages of the fruit was investigated using two different targeted methodologies: ultra-high-performance liquid chromatography–UV/visible detection (UHPLC-UV/vis) for anthocyanins and UHPLC coupled with tandem mass spectrometry (UHPLC-MS/MS) for the other polyphenols. For the specific analysis of anthocyanins, compound identification was confirmed by UHPLC-MS/MS and LC-NMR analysis. This study revealed the identification of 30 phenolic compounds including 9 anthocyanins, 7 flavanols, 7 flavonols, 2 phenolic acids, 1 stilbene, 2 flavanones, 1 flavanonol and 1 dihydrochalcone. Quantification showed significant qualitative and quantitative variation in phenolic content during the ripening of P. lentiscus fruits, flavonols being the main compounds for the unripe berries and anthocyanins for ripe berries. To the best of our knowledge, our study reports the presence of piceid and protocatechuic acid in P. lentiscus L. fruits, as well as several anthocyanins in Pistacia, for the first time. The results indicate potential applications of P. lentiscus L. fruits as a source of phenolic compounds to be used as nutraceuticals and as food colorants

J Agric Food Chem

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

Molecules

ε-Viniferin is a resveratrol dimer that possesses antioxidant or anti-inflammatory activities. However little is known about the metabolism of this oligostilbene. This study was thus undertaken as a first approach to identify and characterize the metabolites of ε-viniferin and to describe the kinetic profile of their appearance in humans and rats. The glucuronides and sulfates of ε-viniferin were first obtained by chemical hemi-synthesis and were fully characterized by UPLC-MS and NMR spectroscopy. Then, ε-viniferin was incubated with human or rat S9 liver fractions that led to the formation of four glucuronoconjugates and four sulfoconjugates. In both species, ε-viniferin was subjected to an intense metabolism as 70 to 80% of the molecule was converted to glucuronides and sulfates. In humans, the hepatic clearance of ε-viniferin (V/K) for glucuronidation and sulfation were 4.98 and 6.35 µL/min/mg protein, respectively, whereas, in rats, the hepatic clearance for glucuronidation was 20.08 vs. 2.59 µL/min/mg protein for sulfation. In humans, three major metabolites were observed: two glucuronides and one sulfate. By contrast, only one major glucuronide was observed in rats. This strong hepatic clearance of ε-viniferin in human and rat could explain its poor bioavailability and could help to characterize its active metabolites