Water Deficit Increases Stilbene Metabolism in Cabernet Sauvignon Berries

The impact of water deficit on stilbene biosynthesis in wine grape (Vitis vinifera) berries was investigated. Water deficit increased the accumulation of trans-piceid (the glycosylated form of resveratrol) by 5-fold in Cabernet Sauvignon berries but not in Chardonnay. Similarly, water deficit significantly increased the transcript abundance of genes involved in the biosynthesis of stilbene precursors in Cabernet Sauvignon. Increased expression of stilbene synthase, but not that of resveratrol-O-glycosyltransferase, resulted in increased trans-piceid concentrations. In contrast, the transcript abundance of the same genes declined in Chardonnay in response to water deficit. Twelve single nucleotide polymorphisms (SNPs) were identified in the promoters of stilbene synthase genes of Cabernet Sauvignon, Chardonnay, and Pinot Noir. These polymorphisms resulted in eight changes within the predicted cis regulatory elements in Cabernet Sauvignon and Chardonnay. These results suggest that cultivar-specific molecular mechanisms might exist that control resveratrol biosynthesis in grapes

Sugar and Polyphenolic Diversity in Floral Nectar of Cherry

Cherries (Prunus avium L. and Prunus cerasus L.) are economically important fruit species in the temperate region. Both are entomophilous fruit species, thus need pollinators to give high yields. Since cherry’s flower is easy-to-reach, bees and other pollinators can smoothly collect nectar as a reward for doing transfer of pollen to receptive stigma. Nectar in cherry is usually attractive for insects, especially to honey bee (Apis mellifera) who is the most common pollinator. Nectar is predominantly an aqueous solution of sugars, proteins, and free amino acids among which sugars are the most dominant. Trace amounts of lipids, organic acids, iridoid glycosides, minerals, vitamins, alkaloids, plant hormones, non-protein amino, terpenoids, glucosinolates, and cardenolides can be found in nectar too. Cherry flower may secrete nectar for 2–4 days and, depending on the cultivar, produces up to 10 mg nectar with sugar concentration from 28% to 55%. Detailed chemical analysis of cherry nectar described in this chapter is focused on sugar and phenolic profile in sour cherry. The most abounded sugars in cherry nectar was fructose, glucose, and sucrose, while arabinose, rhamnose, maltose, isomaltose, trehalose, gentiobiose, turanose, panose, melezitose, maltotriose, isomaltotriose, as well as the sugar alcohols glycerol, erythritol, arabitol, galactitol, and mannitol are present as minor constituents. Regarding polyphenolics, rutin was the most abundant phenolic compound followed by naringenin and chrysin. Cherry cultivars showed different chemical composition of nectar which implies that its content is cultivar dependent

Water deficit alters differentially metabolic pathways affecting important flavor and quality traits in grape berries of Cabernet Sauvignon and Chardonnay

<p>Abstract</p> <p>Background</p> <p>Water deficit has significant effects on grape berry composition resulting in improved wine quality by the enhancement of color, flavors, or aromas. While some pathways or enzymes affected by water deficit have been identified, little is known about the global effects of water deficit on grape berry metabolism.</p> <p>Results</p> <p>The effects of long-term, seasonal water deficit on berries of Cabernet Sauvignon, a red-wine grape, and Chardonnay, a white-wine grape were analyzed by integrated transcript and metabolite profiling. Over the course of berry development, the steady-state transcript abundance of approximately 6,000 Unigenes differed significantly between the cultivars and the irrigation treatments. Water deficit most affected the phenylpropanoid, ABA, isoprenoid, carotenoid, amino acid and fatty acid metabolic pathways. Targeted metabolites were profiled to confirm putative changes in specific metabolic pathways. Water deficit activated the expression of numerous transcripts associated with glutamate and proline biosynthesis and some committed steps of the phenylpropanoid pathway that increased anthocyanin concentrations in Cabernet Sauvignon. In Chardonnay, water deficit activated parts of the phenylpropanoid, energy, carotenoid and isoprenoid metabolic pathways that contribute to increased concentrations of antheraxanthin, flavonols and aroma volatiles. Water deficit affected the ABA metabolic pathway in both cultivars. Berry ABA concentrations were highly correlated with 9-cis-epoxycarotenoid dioxygenase (<it>NCED1</it>) transcript abundance, whereas the mRNA expression of other <it>NCED </it>genes and ABA catabolic and glycosylation processes were largely unaffected. Water deficit nearly doubled ABA concentrations within berries of Cabernet Sauvignon, whereas it decreased ABA in Chardonnay at véraison and shortly thereafter.</p> <p>Conclusion</p> <p>The metabolic responses of grapes to water deficit varied with the cultivar and fruit pigmentation. Chardonnay berries, which lack any significant anthocyanin content, exhibited increased photoprotection mechanisms under water deficit conditions. Water deficit increased ABA, proline, sugar and anthocyanin concentrations in Cabernet Sauvignon, but not Chardonnay berries, consistent with the hypothesis that ABA enhanced accumulation of these compounds. Water deficit increased the transcript abundance of lipoxygenase and hydroperoxide lyase in fatty metabolism, a pathway known to affect berry and wine aromas. These changes in metabolism have important impacts on berry flavor and quality characteristics. Several of these metabolites are known to contribute to increased human-health benefits.</p

Dietary levels of pure flavonoids improve spatial memory performance and increase hippocampal brain-derived neurotrophic factor.

Evidence suggests that flavonoid-rich foods are capable of inducing improvements in memory and cognition in animals and humans. However, there is a lack of clarity concerning whether flavonoids are the causal agents in inducing such behavioral responses. Here we show that supplementation with pure anthocyanins or pure flavanols for 6 weeks, at levels similar to that found in blueberry (2% w/w), results in an enhancement of spatial memory in 18 month old rats. Pure flavanols and pure anthocyanins were observed to induce significant improvements in spatial working memory (p = 0.002 and p = 0.006 respectively), to a similar extent to that following blueberry supplementation (p = 0.002). These behavioral changes were paralleled by increases in hippocampal brain-derived neurotrophic factor (R = 0.46, p<0.01), suggesting a common mechanism for the enhancement of memory. However, unlike protein levels of BDNF, the regional enhancement of BDNF mRNA expression in the hippocampus appeared to be predominantly enhanced by anthocyanins. Our data support the claim that flavonoids are likely causal agents in mediating the cognitive effects of flavonoid-rich foods

Methyl jasmonate/ethephon cotreatment synergistically induces stilbene production in "Vitis vinifera" cell suspensions but fails to trigger resistance to "Erysiphe necator"

Aim: The aim of the present investigation was to determine whether methyl jasmonate and ethylene could synergistically induce grapevine foliar cuttings (Vitis vinifera) defense mechanisms and enhance resistance to Erysiphe necator. Methods and results: We cotreated grapevine foliar cuttings (Cabernet- Sauvignon) with ethylene-releasing ethephon in association with methyl jasmonate. However, this cotreatment did not improve resistance to powdery mildew induced by MeJA or ethephon, alone. Quantitative PCR analysis performed on grape cell suspensions showed that the association ethephon/MeJA triggered an enhancement of phytoalexin biosynthesis by synergistically inducing PAL and STS genes. This gene expression was correlated with accumulation of stilbenes (antimicrobial compounds), assessed by HPLC analysis. However, ethephon seemed to inhibit MeJA-dependent induction of PR protein gene expression mainly for the first eighteen hours. Significance and impact of study: Since methyl jasmonate and ethephon can separately enhance grapevine resistance to Erysiphe necator, it was interesting to study the effect of the association of the two molecules on it. Although we observed a synergistic effect on phytoalexin production, no improved resistance against the fungus was obtained. These results can be exploited for the development of new pest control strategies in vineyard

Stilbenoid chemistry from wine and the genus <em>Vitis</em>, a review

Stilbenoids are of great interest on account of their many promising biological activities, especially in regards to prevention and potential treatment of many chronic diseases associated with aging. The simple stilbenoid monomer, E-resveratrol, has received the most attention due to early in vitro and in vivo biological activities in anti-aging assays. Since Vitis vinifera, primarily in the form of wine, is a major dietary source of these compounds, there is a tremendous amount of research on resveratrol in wine and grapes. Relatively few biological studies have been performed on other stilbenoids from Vitis, primarily due to the lack of commercial sources of many of these compounds. The diverse stilbenoids from this economically important genus are an untapped source of health promoting compounds and because of this, numerous efforts for isolation, identification and quantification of additional stilbenoids have been ongoing. Additionally, due to their role as phytoalexins, stilbenoids play an important role in the defense against pathogens. Therefore, the compounds produced by highly resistant strains are of great interest for the development of resistant crops, natural spray reagents, and as new dietary supplements or pharmaceuticals. Since closely related species are likely to have similar metabolic pathways, a more thorough understanding of the chemical diversity of stilbenoids within Vitis is useful in this endeavor. In this review, we focus on stilbenoids found in the Vitis genus with the aim of aiding future stilbenoid chemistry, particularly in V. vinifera and wine. Additionally, we discuss the efforts to quantify stilbenoids in Vitis, with a focus on non-resveratrol stilbenoid compounds

<em>In vitro</em> glucuronidation of <em>trans</em>-Piceid and <em>trans</em>-Piceatannol by human liver microsomes

Aims : The aim of the present investigation was to establish glucuronidation of trans-resveratrol derivates in the liver. Stilbenes are naturally occurring polyphenolic compounds which have been reported to have potential preventive activities in human diseases. Trans-stilbenes, mainly found in grapes and red wine, are important in terms of biological activities. However, little is known about the metabolism of these compounds in human. Methods and results : The glucuronoconjugation of stilbenes was investigated using human liver microsomes and the structure of new metabolites was characterized by LC-MS and proton NMR. For the first time, the structure of the metabolites of trans-piceid and trans-piceatannol was established. The reaction led to the formation of two glucuronides for trans-piceid and three for trans-piceatannol. Significance and impact of study: This study is of particular relevance since the phenolic substances of red wine (especially stilbenes) might be responsible for the potential beneficial effects of moderate and regular wine consumption

Wine Polyphenols: Potential Agents in Neuroprotection

There are numerous studies indicating that a moderate consumption of red wine provides certain health benefits, such as the protection against neurodegenerative diseases. This protective effect is most likely due to the presence of phenolic compounds in wine. Wine polyphenolic compounds are well known for the antioxidant properties. Oxidative stress is involved in many forms of cellular and molecular deterioration. This damage can lead to cell death and various neurodegenerative disorders, such as Parkinson’s or Alzheimer’s diseases. Extensive investigations have been undertaken to determine the neuroprotective effects of wine-related polyphenols. In this review we present the neuroprotective abilities of the major classes of wine-related polyphenols

J. agric. food chem.

Grapevine is subject to diseases that affect yield and wine quality caused by various pathogens including Botrytis cinerea. To limit the use of fungicides, an alternative is to use plant elicitors such as benzothiadiazole (BTH). We investigated the effect of a fungicide (Pyrimethanil) and an elicitor (benzothiadiazole) on plant defenses. Applications for two consecutive years in the vineyard significantly reduced gray mold. Two and seven days after treatments, the expressions of 48 genes involved in defenses showed differential modulation (up- or down-regulation) depending on treatment. Some genes were identified as potential markers of protection and were linked to an increase in total polyphenols (TP) in leaves. Surprisingly, the fungicide also induced the expression of defense genes and increased the polyphenol content. This suggests that BTH acts as an efficient elicitor in the vineyard and that Pyrimethanil may act, in part, as a defense-inducing agent on the vine