Red wine and components flavonoids inhibit UGT2B17 in vitro

Background The metabolism and excretion of the anabolic steroid testosterone occurs by glucuronidation to the conjugate testosterone glucuronide which is then excreted in urine. Alterations in UGT glucuronidation enzyme activity could alter the rate of testosterone excretion and thus its bioavailability. The aim of this study is to investigate if red wine, a common dietary substance, has an inhibitory effect on UGT2B17. Methods Testosterone glucuronidation was assayed using human UGT2B17 supersomes with quantification of unglucuronidated testosterone over time using HPLC with DAD detection. The selected red wine was analysed using HPLC and the inhibitory effects of the wine and phenolic components were tested independently in a screening assay. Further analyses were conducted for the strongest inhibitors at physiologically relevant concentrations. Control experiments were conducted to determine the effects of the ethanol on UGT2B17. Results Over the concentration range of 2 to 8% the red wine sample inhibited the glucuronidation of testosterone by up to 70% over 2 hours. The ethanol content had no significant effect. Three red wine phenolics, identified by HLPC analyses, also inhibited the enzyme by varying amounts in the order of quercetin (72%), caffeic acid (22%) and gallic acid (9%); using a ratio of phenolic:testosterone of 1:2.5. In contrast p-coumaric acid and chlorogenic acid had no effect on the UGT2B17. The most active phenolic was selected for a detailed study at physiologically relevant concentrations, and quercetin maintained inhibitory activity of 20% at 2 M despite a ten-fold excess of testosterone. Conclusion This study reports that in an in vitro supersome-based assay, the key steroid-metabolising enzyme UGT2B17 is inhibited by a number of phenolic dietary substances and therefore may reduce the rate of testosterone glucuronidation in vivo. These results highlight the potential interactions of a number of common dietary compounds on testosterone metabolism. Considering the variety of foodstuffs that contain flavonoids, it is feasible that diet can elevate levels of circulating testosterone through reduction in urinary excretion. These results warrant further investigation and extension to a human trial to delineate the healt

Phenolic and furanic compounds of Portuguese chestnut and French, American and Portuguese oak wood chips

Botanical species used on aging process must be wisely and judiciously chosen, and for this selection, a basic knowledge of the chemical composition of woods is warranted. Aiming to contribute to extend the knowledge of the chemical composition of several wood species useful for enological purposes, we have focused our studies on Portuguese chestnut and French, American and Portuguese oak chips. The profile of low molecular weight phenolic composition of these chips was achieved, using an optimized extraction method based on pressurized liquid extraction, followed by the quantification of phenolic acids, phenolic aldehydes and furanic derivatives by high-performance liquid chromatography (HPLC-DAD). The identification of those compounds was also confirmed by LC-DAD/ESI-MS. This study allowed the determination of the low molecular phenolic composition of Portuguese chestnut and French, American and Portuguese oak wood. According to our results, the influence of the botanical species seems to be more relevant than the geographic origin of the wood species

New organophosphorus proligands and amide precursors: Crystal and molecular structures of Ph2P(X)NH(C6H3Pr i2-2,6) (X = O, S) and (OPPh2)(O 2SMe)N(C6H3Pri2-2,6)

The new organophosphorus proligand (OPPh2)(O2SMe)NR (R = C6H3Pri2-2,6)(3) was prepared as a white crystalline solid by reacting the lithiated compound Li[Ph 2P(O)NR] with MeSO2Cl in a 1:1 molar ratio. The precursor Ph 2P(O)NHR (1), as well as its thio analogue Ph2P(S)NHR (2), were obtained in the reaction between the lithiated amine RNHLi and the corresponding organophosphorus chloride. All compounds were characterized by multinuclear (1H, 13C, and 31P) NMR spectroscopy. The molecular structures of 1-3 were established by single-crystal X-ray diffraction. A zigzag polymeric chain is formed in the crystals of 1 and 2 by hydrogen N-HX (X = O, S) bonding, while the crystal of 3 contains discrete monomeric units with a syn-syn conformation of the O=P(C)2-N-S(C)(=O)2 skeleton. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file

Determination of rotundone, the pepper aroma impact compound, in grapes and wine

Shiraz, also known as Syrah or Hermitage, is one of Australia’s most popular red wine varieties both domestically and internationally. Black pepper aroma and flavor are important to some Australian Shiraz red wine styles. Recently, rotundone (a bicyclic sesquiterpene) was identified as the potent aroma compound responsible for pepper aromas in grapes, wine, herbs, and spices, including peppercorns. Here the development, optimization, and validation of the analytical method for the quantitative determination of rotundone in grapes and wine are described and discussed. The method is precise, accurate, robust, and sensitive with a subpart per trillion limit of quantitation. The method uses stable isotope dilution analysis with d₅ -rotundone as internal standard, solid-phase extraction and microextraction, and gas chromatography–mass spectrometry.Tracey E. Siebert, Claudia Wood, Gordon M. Elsey and Alan P. Pollnit

Stable isotope dilution analysis of wine fermentation products by HS-SPME-GC-MS

The aim of this study was to quantify, in a single analysis, 31 volatile fermentation-derived products that contribute to the aroma of red and white wine. We developed a multi-component method based on headspace solid-phase microextraction coupled with gas chromatography mass spectrometry (HS-SPME-GC-MS). The 31 volatile compounds analysed include ethyl esters, acetates, acids and alcohols. Although these compounds have a range of functional groups, chemical properties, volatilities, affinities for the SPME fibre, and are found in wine at various concentrations, the accuracy of the analysis was achieved with the use of polydeuterated internal standards for stable isotope dilution analyses (SIDA). Nine of the labelled standards were commercially available, while 22 were synthesised. The method was validated by a series of duplicate spiked standard additions to model, white and red wine matrices over the concentration range relevant for each compound in wine. This demonstrated that the appropriate use of SIDA helped to account for matrix effects, for instance potential sources of variation such as the relative response to the MS detector, ionic strength, ethanol content and pH of different wine matrices. The resultant calibration functions had correlation coefficients (R(2)) ranging from 0.995 to 1.000. Each compound could be quantified at levels below its aroma threshold in wine. Relative standard deviations were all <5%. The method was optimised for the best compromise (over the 31 compounds) of wine dilution factor, level of sodium chloride addition, SPME fibre, SPME temperature, SPME time, GC column and MS conditions. Confirmation of identity was achieved by retention time and peak shape, and measurement of at least three ions for each analyte and internal standard with the MS operating in selected ion monitoring mode to facilitate more precise quantitation with a high sampling rate. The method is a valuable research tool with many relevant applications. A novel method for the combined chiral separation and SIDA quantification of 2- and 3-methylbutanoic acid is also demonstrated

From Wine to Pepper: Rotundone, an Obscure Sesquiterpene, Is a Potent Spicy Aroma Compound

Copyright © 2008 American Chemical SocietyAn obscure sesquiterpene, rotundone, has been identified as a hitherto unrecognized important aroma impact compound with a strong spicy, peppercorn aroma. Excellent correlations were observed between the concentration of rotundone and the mean ‘black pepper’ aroma intensity rated by sensory panels for both grape and wine samples, indicating that rotundone is a major contributor to peppery characters in Shiraz grapes and wine (and to a lesser extent in wine of other varieties). Approximately 80% of a sensory panel were very sensitive to the aroma of rotundone (aroma detection threshold levels of 16 ng/L in red wine and 8 ng/L in water). Above these concentrations, these panelists described the spiked samples as more ‘peppery’ and ‘spicy’. However, approximately 20% of panelists could not detect this compound at the highest concentration tested (4000 ng/L), even in water. Thus, the sensory experiences of two consumers enjoying the same glass of Shiraz wine might be very different. Rotundone was found in much higher amounts in other common herbs and spices, especially black and white peppercorns, where it was present at 10000 times the level found in very ‘peppery’ wine. Rotundone is the first compound found in black or white peppercorns that has a distinctive peppery aroma. Rotundone has an odor activity value in pepper on the order of 50000−250000 and is, on this criterion, by far the most powerful aroma compound yet found in that most important spice.Claudia Wood, Tracey E. Siebert, Mango Parker, Dimitra L. Capone, Gordon M. Elsey, Alan P. Pollnitz, Marcus Eggers, Manfred Meier, Tobias Vössing, Sabine Widder, Gerhard Krammer, Mark A. Sefton and Markus J. Herderic

Rates of formation of cis- and trans-oak lactone from 3-methyl-4- hydroxyoctanoic acid

The rates of formation of both cis- and trans-oak lactone from the corresponding isomers of 3-methyl-4-hydroxyoctanoic acid have been measured in model wine at room temperature for a range of pH values. The half-life for formation of the trans-isomer at pH 2.9 was calculated to be 3.1 h, whereas that for the cis-isomer, at the same pH, was calculated to be 40.5 h. The ktrans/kcis ratio in model wine was found to 12.86 ± 1.34 over the range of pH values employed. A reason for the more facile formation of the trans-isomer, based on conformational reasons, has been proposed. In acidic aqueous media the equilibrium between the oak lactones and their corresponding ring-opened analogues was found to favor the former entirely, with no evidence for the latter being found. Implications of the present study for the future analysis of oak samples, as well as for the interpretation of existing data, are discussed