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Biomedical subjects

Andrew L Waterhouse

Publications and source records attributed to Andrew L Waterhouse.

11 recordsLinked to original sources
PubMed2006

Glyceraldehyde bridging between flavanols and malvidin-3-glucoside in model solutions.

Hydroxyl radicals (.OH) seem to have an important role in the oxidation of wine constituents and the production of important electrophilic aldehydes and ketones. In this experiment, glyceraldehyde, a .OH oxidation product of glycerol, recently described in wine, reacts with (+)-catechin, (-)-epicatechin, and malvidin-3-glucoside (Mv3gl), in model solutions, yielding new condensed phenolic compounds. The adduct compounds formed were separated by means of reversed phase liquid chromatography and detected and characterized using UV-vis and electrospray ionization mass spectrometry. Flavanol-flavanol and anthocyanin-flavanol adducts linked with glyceraldehyde yielded compounds with m/z ratios for their main ions, in positive ion mode, of 653.2 for the (+)-catechin dimer or the (-)-epicatechin dimer and 855.5 for Mv3gl/(+)-catechin or Mv3gl/(-)-epicatechin dimers. The possible occurrence of these compounds in wine is suggested, and the potential role of these and related reactions in wine aging is discussed.

Anthocyanins↗
PubMed2006

Oxidation of glycerol in the presence of hydrogen peroxide and iron in model solutions and wine. Potential effects on wine color.

Wine oxidation appears to include the formation of hydroxyl radical (*OH), an exceptionally reactive and thus nonselective compound that might be involved in the production of important aldehydes and ketones. This experiment examined the *OH oxidation of glycerol, a major wine constituent, and thus a likely target of such oxidation, in model wine, generated by hydrogen peroxide and iron catalysis. The oxidation products generated were analyzed as their hydrazones using LC-DAD/MS. Glyceraldehyde and dihydroxyacetone were the main compounds identified, both of which were also observed in naturally aged and *OH-oxidized wines. As anticipated, the presence of ethanol in the model wine did not preclude the formation of these compounds. Additionally, when a young red wine was treated with these oxidation derivatives, a noteworthy increase in color was observed, most likely due to the formation of novel anthocyanin-based structures.

Chromatography, Liquid↗
PubMed2006

A simple method to separate red wine nonpolymeric and polymeric phenols by solid-phase extraction.

Simple polyphenols and tannins differ in the way that they contribute to the organoleptic profile of wine and their effects on human health. Very few straightforward techniques to separate red wine nonpolymeric phenols from the polymeric fraction are available in the literature. In general, they are complex, time-consuming, and generate large amounts of waste. In this procedure, the separation of these compounds was achieved using C18 cartridges, three solvents with different elution strengths, and pH adjustments of the experimental matrices. Two full factorial 2(3) experimental designs were performed to find the optimal critical variables and their values, allowing for the maximization of tannin recovery and separation efficiency (SE). Nonpolymeric phenols such as phenolic acids, monomers, and oligomers of flavonol and flavan-3-ols and anthocyanins were removed from the column by means of an aqueous solvent followed by ethyl acetate. The polymeric fraction was then eluted with a combination of methanol/acetone/water. The best results were attained with 1 mL of wine sample, a 10% methanol/water solution (first eluant), ethyl acetate (second eluant), and 66% acetone/water as the polymeric phenols-eluting solution (third eluant), obtaining a SE of ca. 90%. Trials with this method on fruit juices also showed high separation efficiency. Hence, this solid-phase extraction method has been shown to be a simple and efficient alternative for the separation of nonpolymeric phenolic fractions and the polymeric ones, and this method could have important applications to sample purification prior to biological testing due to the nonspecific binding of polymeric phenolics to nearly all enzymes and receptor sites.

Acetone↗
PubMed2005

Consumer labels can convey polyphenolic content: implications for public health.

Polyphenolics are a large group of related substances. Many of these, in fact much of that found in food, is composed of processing-derived substances too complex for complete identification. Recent studies have suggested likely benefits for diets high in polyphenols, particular in reducing heart disease mortality, but other benefits have also been suggested. A consumer label based on the major polyphenolic classes is both manageable and fairly informative as most foods do not contain all possible classes. Differences between class member can be significant, but data on individual substances is impractical and no data is certainly less informative. Equivalency scales may be useful but may skew content of many foods towards the high-equivalency substances, even while the full beneficial effects of each individual substance is poorly described.

Community Participation↗
PubMed2003

An assay to estimate tannins added to postmortem Turkey meat.

A method for quantification of tannins in wine was adapted to determine tannins added to turkey meat. Standard curves containing varying amounts of GSE [0, 0.5, 1.0, 1.5, 2.0, 2.5, and 5.0%, (w/w)] as a source of tannins were developed. The R(2) value of the mean standard curve was 0.9992. The overall percent recovery of GSE in meat was determined to be 54.78%. Results showed that estimation of GSE in four out of five of the spiked samples was less than or equal to 10%. It is unclear as to why spiked samples at 0.048 mg of GSE were always underestimated (25.0%). Overall, the method seems applicable for estimation of tannins in poultry meat and is probably applicable to estimation of tannins in other meat products.

Animals↗
PubMed2002

The present and future of the international wine industry.

Wine production is both art and science, a blend of individual creativity and innovative technology. But wine production is also business, with economic factors driving manufacturing practices. To be successful in the modern marketplace, a winemaker must integrate the artistic and economic aspects of wine production, and possess a solid understanding of the intrinsic and extrinsic factors that underlie purchase motivation.

Agriculture↗
PubMed2002

Enzymatic synthesis of [3'-O-methyl-(3)H]malvidin-3-glucoside from petunidin-3-glucoside.

Malvidin-3-glucoside has been labeled by enzymatic synthesis in a single-step experiment. Catechol-O-methyl transferase catalyzed the B-ring methylation of petunidin-3-glucoside, and S-Adenosyl-L-[methyl-(3)H] methionine was the methyl donor. Solid phase extraction and preparative high-performance liquid chromatography were necessary to separate [3'-O-methyl-(3)H]malvidin-3-glucoside from an isomer and the starting material. The specific activity was 2.2 Ci mmol(-1), and the yield of incorporation was 1.1%. A possible application of the labeled material is the study of anthocyanin reactions in complex mixtures such as red wine where products are difficult to isolate and analyze.

Anthocyanins↗
PubMed2002

Inhibition of vascular smooth muscle cell proliferation with red wine and red wine polyphenols.

OBJECTIVE: The potential beneficial effects of red wine consumption on the development of atherosclerotic disease have been previously suggested in the literature. Vascular smooth muscle cell (SMC) proliferation is an important component of atherogenesis. Inhibition of vascular SMC proliferation may have a beneficial effect in retarding the development of atherosclerotic disease. The goal of this study was to determine the effect of red wine, red wine polyphenol extract, and resveratrol, a polyphenol commonly found in red wine, on the proliferation of vascular SMC in culture. METHODS: Bovine aortic SMCs were used for all experiments. SMCs were treated with growth media supplemented with dealcoholized red wine, red wine polyphenol extract, or resveratrol at various concentrations for as long as 48 hours. SMC proliferation was assessed with (3)H-thymidine DNA incorporation assay. SMC viability was assessed with trypan blue exclusion studies and a colorimetric lactic dehydrogenase cytotoxicity assay. RESULTS: Our results show that red wine and red wine polyphenol extract inhibit SMC proliferation in a dose-dependent fashion. Resveratrol also inhibits vascular SMC proliferation. SMC viability studies show that this inhibition of SMC proliferation is not the result of a cytotoxic effect. CONCLUSION: Our findings show that red wine and red wine polyphenols have an inhibitory effect on the proliferation of vascular SMCs in culture. These results suggest that the observed beneficial effects of red wine may be the result, in part, of the inhibition of vascular SMC proliferation. Furthermore, the antiproliferative properties of red wine may be caused by its component polyphenols.

Animals↗
PubMed2002

Urinary excretion of catechin metabolites by human subjects after red wine consumption.

Little is known about flavonoid metabolism and excretion in man. In the present study, the urinary excretion of a major flavonoid in wine, catechin, and its metabolites, were measured after nine human subjects each consumed 120 ml red wine (RW) on one day and de-alcoholized red wine (DRW) on a separate day. Both the RW and DRW contained 120 (SEM 3) micromol catechin (35 mg). GC-MS analyses of the trimethylsilylated derivatives of catechin and 3' and 4' methylcatechin were performed before and after hydrolysis of conjugates by beta-glucuronidase and sulfatase. Baseline urine samples collected prior to wine consumption contained 0.013 (SEM 0.005) micromol catechin and metabolites. During the 8 h period following consumption of RW and DRW, 6.6 (SEM 0.9) and 5.3 (SEM 0.6) micromol catechin and metabolites were excreted in 893 (SEM 94) and 740 (SEM 101) ml urine respectively. This corresponded to 3.0-10.3% of the dose after RW and 2.1-8.2% of the dose after DRW. The amount of catechin and metabolites excreted in urine was 20% higher after RW compared with DRW (P=0.06). Catechin in all urine samples was present as metabolites and there were no differences in the proportions of individual metabolites after RW and DRW. As with other flavonoids, the fate of most ingested catechin is not yet known.

Adult↗
PubMed2002

Wine phenolics.

Wine contains many phenolic substances, most of which originate in the grape berry. The phenolics have a number of important functions in wine, affecting the tastes of bitterness and astringency, especially in red wine. Second, the color of red wine is caused by phenolics. Third, the phenolics are the key wine preservative and the basis of long aging. Lastly, since phenolics oxidize readily, they are the component that suffers owing to oxidation and the substance that turns brown in wine (and other foods) when exposed to air. Wine phenolics include the non-flavonoids: hydroxycinnamates, hydroxybenzoates and the stilbenes; plus the flavonoids: flavan-3-ols, the flavonols, and the anthocyanins. While polymeric condensed tannins and pigmented tannins constitute the majority of wine phenolics, their large size precludes absorption and thus they are not likely to have many health effects (except, perhaps, in the gut). The total amount of phenols found in a glass of red wine is on the order of 200 mg versus about 40 mg in a glass of white wine.

Anthocyanins↗