Survey of the Free and Conjugated Myricetin and Quercetin Content of Red Wines of Different Geographical Origins

A recent update on the connection between dietary phytochemicals and skin cancer: emerging understanding of the molecular mechanism

Constant exposure to harmful substances from both inside and outside the body can mess up the body's natural ways of keeping itself in balance. This can cause severe skin damage, including basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma. However, plant-derived compounds found in fruits and vegetables have been shown to protect against skin cancer-causing free radicals and other harmful substances. It has been determined that these dietary phytochemicals are effective in preventing skin cancer and are widely available, inexpensive, and well-tolerated. Studies have shown that these phytochemicals possess anti-inflammatory, antioxidant, and antiangiogenic properties that can aid in the prevention of skin cancers. In addition, they influence crucial cellular processes such as angiogenesis and cell cycle control, which can halt the progression of skin cancer. The present paper discusses the benefits of specific dietary phytochemicals found in fruits and vegetables, as well as the signaling pathways they regulate, the molecular mechanisms involved in the prevention of skin cancer, and their drawbacks.

A critical examination of human data for the biological activity of quercetin and its phase-2 conjugates

This critical review examines evidence for beneficial effects of quercetin phase-2 conjugates from clinical intervention studies, volunteer feeding trials, and in vitro work. Plasma concentrations of quercetin-3-O-glucuronide (Q3G) and 3'-methylquercetin-3-O-glucuronide (3'MQ3G) after supplementation may produce beneficial effects in macrophages and endothelial cells, respectively, especially if endogenous deglucuronidation occurs, and lower blood uric acid concentration via quercetin-3'-O-sulfate (Q3'S). Unsupplemented diets produce much lower concentrations (<50 nmol/l) rarely investigated in vitro. At 10 nmol/l, Q3'S and Q3G stimulate or suppress, respectively, angiogenesis in endothelial cells. Statistically significant effects have been reported at 100 nmol/l in breast cancer cells (Q3G), primary neuron cultures (Q3G), lymphocytes (Q3G and3'MQ3G) and HUVECs (QG/QS mixture), but it is unclear whether these translate to a health benefit in vivo. More sensitive and more precise methods to measure clinically significant endpoints are required before a conclusion can be drawn regarding effects at normal dietary concentrations. Future requirements include better understanding of inter-individual and temporal variation in plasma quercetin phase-2 conjugates, their mechanisms of action including deglucuronidation and desulfation both in vitro and in vivo, tissue accumulation and washout, as well as potential for synergy or antagonism with other quercetin metabolites and metabolites of other dietary phytochemicals.

Modulation of the gut microbiota: opportunities and regulatory aspects

The human gut is an intensively colonized organ containing microorganisms that can be health-promoting or pathogenic. This feature led to the development of functional foods aiming to fortify the former category at the expense of the latter. Since long, cultured products, including probiotics fortification, have been used for humans as live microbial feed additions. This review presents some of the microbes used as probiotics and discusses how supplementation with probiotics may help initiate and/or restore eubiotic composition of gut microbiota. Additionally, it considers safety and regulatory aspects of probiotics.

Myricetin Increases Circulating Adropin Level after Activation of Glucagon-like Peptide 1 (GLP-1) Receptor in Type-1 Diabetic Rats

Myricetin is a common plant-derived flavonoid, considered an agonist of glucagon-like peptide 1 (GLP-1) receptor. It improves glycemic control and helps reduce body weight in diabetic subjects. The potential mechanisms of action of myricetin in this context might be enhancing the secretion of β-endorphin (BER) to activate peripheral μ-opioid receptors. Moreover, adropin is a nutritionally regulated peptide hormone, which regulates energy metabolism, and plays a role in ameliorating diabetes. Because their mechanisms of insulin sensitivity are closely related, we hypothesized that myricetin may interact with adropin and plasma BER. The present study investigated the glucose-lowering effect of acute and chronic treatments of myricetin in type-1 diabetic rats. Plasma BER and adropin levels were determined by enzyme-linked immunosorbent assay (ELISA). The secretion of BER was measured in rats who received adrenalectomy. The changes in adropin gene (Enho) or mRNA level of GLP-1 receptor were measured using qPCR analysis. The results showed that myricetin dose-dependently increased plasma BER and adropin levels like the reduction of hyperglycemia after bolus injection as acute treatment. In addition, these effects of myricetin were inhibited by the antagonist of GLP-1 receptor. Moreover, in HepG2 cell line, myricetin induced GLP-1 receptor activation, which modulated the expression of adropin. In diabetic rats, the plasma adropin increased by myricetin is mainly through endogenous β-endorphin after activation of GLP-1 receptor via bolus injection as acute treatment. Additionally, chronic treatment with myricetin increased adropin secretion in diabetic rats. In conclusion, our results provide a new finding that activation of opioid μ-receptor in the liver may enhance circulating adropin in animals.

Chemical Composition and Polyphenolic Compounds of Red Wines: Their Antioxidant Activities and Effects on Human Health—A Review

Red wine, an alcoholic beverage is composed of a spectrum of complex compounds such as water, alcohol, glycerol, organic acid, carbohydrates, polyphenols, and minerals as well as volatile compounds. Major factors that affect the levels of phenolic compounds in red wines are the variety of grapes and the storage of the wines. Among the constituents of red wine, phenolic compounds play a crucial role in attributes including color and mouthfeel and confer beneficial properties on health. Most importantly, phenolic compounds such as flavanols, flavonols, flavanones, flavones, tannins, anthocyanins, hydroxycinnamic acids, hydroxybenzoic acids, and resveratrol can prevent the development of cardiovascular diseases, cancers, diabetes, inflammation, and some other chronic diseases.

The diversity in sensitivity of TRPA1 and TRPV1 of various animals to polyphenols

The perception of tastes is sensed by the receptors that stimulate sensory cells. We previously reported that TRPA1 and TRPV1 channels expressed in the oral cavity of mammals, are activated by the auto-oxidized product of epigallocatechin gallate (oxiEGCG), a major astringent catechin in green tea. Here, we investigated and compared the sensitivity of TRPA1 and TRPV1 from various animals to astringent polyphenols. We selected three polyphenols, oxiEGCG, tannic acid and myricetin. HEK293T cells expressing TRPA1 or TRPV1 from mammal, bird, reptile, amphibian, and fish, were analyzed for their activation by the Ca²⁺-imaging. We found the apparent diversity in the polyphenol-sensitivity among various animals. Mammalian TRPs showed relatively higher sensitivity to polyphenols, and especially, human TRPA1 and TRPV1 could be activated by all of three polyphenols at 20 μM. Reptile TRP channels, however, were insensitive to any polyphenols examined. Moreover, the polyphenol-sensitivity of zebrafish TRPA1 and TRPV1 was quite different from that of medaka TRP channels. Since many polyphenols are present in plants and the sensing of polyphenols using TRP channels in the oral cavity might cause astringent taste, the observed diversity of the polyphenol-sensitivity of TRP channels might be involved in the divergence in the food habit of various animals.

Sunburn in Grapes: A Review

Sunburn is a physiological disorder that affects the visual and organoleptic properties of grapes. The appearance of brown and necrotic spots severely affects the commercial value of the fruit, and in extreme cases, significantly decreases yield. Depending on the severity of the damage and the driving factors, sunburn on grapes can be classified as sunburn browning (SB) or as sunburn necrosis (SN). Sunburn results from a combination of excessive photosynthetically active radiation (PAR) and UV radiation and temperature that can be exacerbated by other stress factors such as water deficit. Fruit respond to these by activating antioxidant defense mechanisms, de novo synthesis of optical screening compounds and heat-shock proteins as well as through morphological adaptation. This review summarizes the current knowledge on sunburn in grapes and compares it with relevant literature on other fruits. It also discusses the different factors affecting the appearance and degree of sunburn, as well as the biochemical response of grapes to this phenomenon and different potential mitigation strategies. This review proposes further directions for research into sunburn in grapes.

Simulating Absorption Spectra of Flavonoids in Aqueous Solution: A Polarizable QM/MM Study

We present a detailed computational study of the UV/Vis spectra of four relevant flavonoids in aqueous solution, namely luteolin, kaempferol, quercetin, and myricetin. The absorption spectra are simulated by exploiting a fully polarizable quantum mechanical (QM)/molecular mechanics (MM) model, based on the fluctuating charge (FQ) force field. Such a model is coupled with configurational sampling obtained by performing classical molecular dynamics (MD) simulations. The calculated QM/FQ spectra are compared with the experiments. We show that an accurate reproduction of the UV/Vis spectra of the selected flavonoids can be obtained by appropriately taking into account the role of configurational sampling, polarization, and hydrogen bonding interactions.

Quercetin: Antiviral Significance and Possible COVID-19 Integrative Considerations

Quercetin, a naturally occurring dietary flavonoid, is well known to ameliorate chronic diseases and aging processes in humans, and its antiviral properties have been investigated in numerous studies. In silico and in vitro studies demonstrated that quercetin can interfere with various stages of the coronavirus entry and replication cycle such as PLpro, 3CLpro, and NTPase/helicase. Due to its pleiotropic activities and lack of systemic toxicity, quercetin and its derivatives may represent target compounds to be tested in future clinical trials to enrich the drug arsenal against coronavirus infections. There is evidence that quercetin in combination with, for example, vitamins C and D, may exert a synergistic antiviral action that may provide either an alternative or additional therapeutic/preventive option due to overlapping antiviral and immunomodulatory properties. This review summarizes the antiviral significance of quercetin and proposes a possible strategy for the effective utilization of natural polyphenols in our daily diet for the prevention of viral infection.

Bioactive Compounds and Metabolites from Grapes and Red Wine in Breast Cancer Chemoprevention and Therapy

Phytochemicals and their metabolites are not considered essential nutrients in humans, although an increasing number of well-conducted studies are linking their higher intake with a lower incidence of non-communicable diseases, including cancer. This review summarizes the current findings concerning the molecular mechanisms of bioactive compounds from grapes and red wine and their metabolites on breast cancer-the most commonly occurring cancer in women-chemoprevention and treatment. Flavonoid compounds like flavonols, monomeric catechins, proanthocyanidins, anthocyanins, anthocyanidins and non-flavonoid phenolic compounds, such as resveratrol, as well as their metabolites, are discussed with respect to structure and metabolism/bioavailability. In addition, a broad discussion regarding in vitro, in vivo and clinical trials about the chemoprevention and therapy using these molecules is presented.

New insights into the formation of precipitates of quercetin in Sangiovese wines

Wines produced from Sangiovese (sg) grapes, the most cultivated red grape variety in Italy and widely grown across the world, is often subjected to loss of clarity due to the formation of a deposit constituted by fine needle-shaped crystals. In this work, a qualitative study by ¹H-NMR and ¹³C-NMR analysis of the deposit obtained by filtering cloudy sg wines showed that it was constituted by crystals of quercetin (Q). The analysis of hydro-alcoholic solutions (12% ethanol and pH 3.2.) and red wines added with increasing amounts of Q showed that, above 3 mgL^-1 of Q, a deposit can be detected and, the time necessary for its formation depends on the medium. The comparison among sg and other 11 monovarietal wines showed that sg was the richest in Q and quercetin glycosides (GQ). Both Q and GQ decreased in the analyzed solutions over time and the decrease was faster for Q than for GQ. The controlled exposure to oxygen determined a decrease of Q higher than the 50% of the initial values. Data obtained in this study suggested that practices as micro-oxygenation and wood aging could help to decrease the amount of Q in sg wines.

The effect of quercetin on microRNA expression: A critical review

Quercetin, a flavonoid with multiple proven health benefits to both man and animals, displays a plethora of biological activities, collectively referred to as pleiotropic. The most studied of these are antioxidant and anti-inflammatory but modulation of signalling pathways is important as well. One of the lesser-known and recently discovered roles of quercetin, is modulation of microRNA (miRNA) expression. miRNAs are important posttranscriptional modulators that play a critical role in health and disease and many of these non-coding oligonucleotides are recognized as oncogenic or tumor suppressor miRNAs. This review is an evaluation of the recent relevant literature on the subject, with focus on the ability of quercetin to modulate miRNA expression. It includes a summary of recent knowledge on miRNAs deregulated by quercetin, an overview of quercetin pharmacokinetics and miRNA biogenesis, for the interested reader.

Myricetin ameliorates atherosclerosis in the low-density-lipoprotein receptor knockout mice by suppression of cholesterol accumulation in macrophage foam cells

Background

Myricetin, a major flavonoid found in several foods including berries, grapes and wine, exhibited strong antioxidant potency, yet the effect on atherosclerosis is not fully understood. In this study, we examined the effect of myricetin on lipid accumulation in macrophage and atherosclerosis in atherosclerosis-prone low density lipoprotein receptor-deficient (Ldlr ^-/- ) mice.

Methods

Ldlr ^-/- mice were fed an atherogenic diet supplemented with myricetin (0.15% in the diet, v/v) for 8 weeks. Body weight, adipose tissue weight, food intake, serum biochemical parameters were measured. Atherosclerosis lesions and macrophages accumulaton in lesions were analyzed and quantified. Macrophages were exposed to 20 μM of myricetin before incubated with oxidized low-density lipoprotein (ox-LDL) (25μg/mL) or Dil-ox-LDL for the indicated time. Lipid uptake and foam cell formation were evaluated by flow cytometry and microscopy. The intracellular lipids were extracted and measured. mRNA expression and protein of cholesterol metabolism related receptors were analyzed.

Results

Myricetin administration reduced the weight, plasma lipid levels but not food intake in Ldlr ^-/- mice when fed an atherogenic diet. Myceritin-treated Ldlr ^-/- mice displayed significantly less atherosclerotic areas and macrophages in the cross sections of the aortic root. There were also less lipophilic areas in En face Oil red O staining of aorta from myceritin-treated Ldlr ^-/- mice. Myceritin treatment also markedly ameliorated ox-LDL-induced cholesterol accumulation in macrophages. The expression of CD36 were decreased in myricetin treated macrophages with ox-LDL incubation, while scavenger receptors class A (SR-A) and scavenger receptors class B (SR-BI) expression was not altered, indicating that these effect of myricetin were dependent on CD36 pathway.

Conclusions

Our findings indicated that myricetin suppressed cholesterol accumulation in macrophage foam cells by inhibition of CD36-mediated ox-LDL uptake, and suggested myricetin may have an important therapeutic function for atherosclerosis.

Comprehensive comparison of antioxidant properties of tinctures

Homemade tinctures, traditional Polish alcoholic beverages called “nalewkas” (similar to alcohol herbal tinctures), which antioxidant capacity have never been studied before, were characterized by electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR) and ultraviolet visible (UV-vis) spectroscopy. The antioxidant properties of nalewkas made according to homemade recipes were compared to commercially produced nalewkas. The impact of aging on antioxidant properties of nalewkas was investigated. The results showed that all of examined nalewkas exhibited strong antioxidant properties (antioxidant capacity TEAC_DPPH 466 μmol TE/100 mL – 11890 μmol TE/100 mL). It was found that the value of the antioxidant capacity corresponds to the total phenolic and aromatic proton content. The impact of the production method and the type of fruit used on the TEAC_DPPH value was also noted. The unripe walnuts with green husks has the highest value of the antioxidant capacity TEAC_DPPH (11890 µM/100 mL) not only for alcoholic beverages, but also among food products.

Red wine and green tea flavonoids are cis-allosteric activators and competitive inhibitors of glucose transporter 1 (GLUT1)-mediated sugar uptake

The antioxidant- and flavonoid-rich contents of red wine and green tea are reported to offer protection against cancer, cardiovascular disease, and diabetes. Some studies, however, show that flavonoids inhibit GLUT1-mediated, facilitative glucose transport, raising the possibility that their interaction with GLUT1 and subsequent downstream effects on carbohydrate metabolism may also impact health. The present study explores the structure-function relationships of flavonoid-GLUT1 interactions. We find that low concentrations of flavonoids act as cis-allosteric activators of sugar uptake, whereas higher concentrations competitively inhibit sugar uptake and noncompetitively inhibit sugar exit. Studies with heterologously expressed human GLUT1, -3, or -4 reveal that quercetin-GLUT1 and -GLUT4 interactions are stronger than quercetin-GLUT3 interactions, that epicatechin gallate (ECG) is more selective for GLUT1, and that epigallocatechin gallate (EGCG) is less GLUT isoform-selective. Docking studies suggest that only one flavonoid can bind to GLUT1 at any instant, but sugar transport and ligand-binding studies indicate that human erythrocyte GLUT1 can bind at least two flavonoid molecules simultaneously. Quercetin and EGCG are each characterized by positive, cooperative binding, whereas ECG shows negative cooperative binding. These findings support recent studies suggesting that GLUT1 forms an oligomeric complex of interacting, allosteric, alternating access transporters. We discuss how modulation of facilitative glucose transporters could contribute to the protective actions of the flavonoids against diabetes and Alzheimer's disease.

Estimation of polyphenols by using HPLC-DAD in red and white wine grape varieties grown under tropical conditions of India

Grapes are well known for their high content of phenolic compounds. Polyphenols are classified into flavonoids and non-flavonoids by their primary chemical structures of hydroxybenzene. Flavonoids mainly consist of anthocyanins, flavonoids, and flavonols whereas non-flavonoids include hydroxycinnamic and hydroxybenzoic acids. In the present study, sixteen phenolic compounds from ten red and nine white grape wine varieties were quantified using high-performance liquid chromatography. Gallic acid, Vanillic acid, Rutin hydrate, Ellagic acid, Chlorogenic acid, Sorbic acid, Catechin hydrate, Epicatechin, p-coumaric acid, Quercetin, Myricetin, Kaempferol, Piceatannol, and Resveratrol were major compounds found in red wine grapes. Among the varieties, Petit Verdot, Cabernet Franc showed maximum quantitative phenolics, whereas Cabernet Sauvignon, Niellucio, Cinsaut, and Syrah showed least quantitative phenolics in grape berries. Phenolic profile of white wine grapes showed lower concentration of phenolics than that of red wine grapes. The variety Gros Meseng showed maximum phenolics followed by Sauvignon, while the variety Colombard and Chenin Blanc showed least phenolics.

Effects of Myricetin-Containing Ethanol Solution on High-Fat Diet Induced Obese Rats

Myricetin is a natural flavonol widely occurring in wines. Many beneficial effects of myricetin in alcoholic beverages have been reported before, but never including anti-obesity. In the present study, we fed obese male Sprague-Dawley rats with ethanol solutions containing various concentrations of myricetin and found that myricetin may maintain the food intake while reduce the weight-gain, feed efficiency, level of blood lipids, adipocyte size, and weight and size of the perirenal and epididymal adipose tissues (P < 0.01). Our experiment data also show that the anti-obesity effect may be associated with the upregulation of adropin and β-endorphin levels. Based on the above-described findings, we propose the potential for myricetin-containing alcoholic beverages to be developed into anti-obesity health food.

Effect of interaction of epigallocatechin gallate and flavonols on color alteration of simulative green tea infusion after thermal treatment

Epigallocatechin gallate (EGCG) and flavonols are important phenolic compounds in green tea. These compounds are sensitive to thermal condition and their structural alteration results in making browning the green tea infusion. This study aimed to research the interaction between EGCG and flavonols during thermal infusion. EGCG and flavonols model solutions were prepared based on concentration in green tea infusion, and their colors appearance and attributes were analyzed in 10 h by thermal treatment. Results showed that kaempferol, quercetin, and myricetin accelerated the oxidation of EGCG and made the model solution browning. HPLC analysis revealed there was an obvious shift of a broaden peak in the mixed model solution of EGCG and flavonols after thermal treatment. This broaden peak was further purified on HPLC and solid phase extraction methods to yield colored complexes. The complexes showed the maximal absorption around 424, 442, and 482 nm. MS/MS analysis revealed that the complexes possessed of three components those were consisted of the interaction between EGCG and myricetin. These results indicated that the interaction between EGCG and flavonols might form complexes during thermal treatment, The complexes were contributed to make green tea infusion browning.

Broad-spectrum of antimicrobial properties of commercial wines from different Vitis vinifera L. varieties

Fifteen commercial wines produced from international and autochthonic varieties of Vitis vinifera L. cultivation of different Balkan winegrowing subregions were studied for their antimicrobial activity against six Gram-positive (Clostridium perfringens, Bacillus subtilis, Staphylococcus aureus, Listeria inocua, Sarcina lutea and Micrococcus flavus) and six Gram-negative (Escherichia coli, Pseudomonas aeruginosa, Salmonella enteritidis, Shigella sonnei, Klebsiella pneumonia and Proteus vulgaris) bacteria. The concentrations and types of phenolic compounds responsible for antibacterial activity in wines were investigated by HPLC and spectroscopic methods. The correlation between amounts of phenolics and antibacterial activities of investigated wines were studied by application of statistical (PCA, factor and cluster) analyses. This study gives the possibility to predict the biological quality of the wine from the same cluster towards bacteria without "wet" analysis. Obtained results can to be useful both to wine producers for the formation of market price of wine, and to wine consumers in choosing quality red wine with high content of polyphenols.

Low Molecular Weight Phenolic and Anthocyanin Composition of Grape Skins from cv. Syrah (Vitis vinifera L.) in the Maipo Valley (Chile): Effect of Clusters Thinning and Vineyard Yield

Changes in phenolic composition were determined in cv. Syrah-vines grape skins during ripening for two contrasting yields, resulting from cluster thinning at veraison. Treatments consisted on 16 and eight clusters per plant leading to approximately 8 ton/ha (T1) and 4 ton/ha (T2). In the grape skins of the samples analysed, 11 different low molecular weight phenolic compounds were identified, as well as 15 anthocyanins. Cluster thinning had a minimal effect on ripening time and weight of grape skins, however, clusters from low yield plants resulted in a lower total acidity and slightly higher pH. As for the phenylpropanoid pathway, the flavan-3-ol (+)-catechin, and the flavanols isorhamnetin-3- O-galactoside and isorhamnetin-3- O-glucoside, resulted in a higher concentration in berry skins from low yield plants. It is concluded that cluster thinning may result, from the oenological point of view, in an increased grape quality especially in compounds related to wine colour.

Genetic Variation of Flavonols Quercetin, Myricetin, and Kaempferol in the Sri Lankan Tea (Camellia sinensis L.) and Their Health-Promoting Aspects

Flavonol glycosides in tea leaves have been quantified as aglycones, quercetin, myricetin, and kaempferol. Occurrence of the said compounds was reported in fruits and vegetable for a long time in association with the antioxidant potential. However, data on flavonols in tea were scanty and, hence, this study aims to envisage the flavonol content in a representative pool of accessions present in the Sri Lankan tea germplasm. Significant amounts of myricetin, quercetin, and kaempferol have been detected in the beverage type tea accessions of the Sri Lankan tea germplasm. This study also revealed that tea is a good source of flavonol glycosides. The Camellia sinensis var. sinensis showed higher content of myricetin, quercetin, and total flavonols than var. assamica and ssp. lasiocalyx. Therefore flavonols and their glycosides can potentially be used in chemotaxonomic studies of tea germplasm. The nonbeverage type cultivars, especially Camellia rosaflora and Camellia japonica Red along with the exotic accessions resembling China type, could be useful in future germplasm studies because they are rich sources of flavonols, namely, quercetin and kaempferol, which are potent antioxidants. The flavonol profiles can be effectively used in choosing parents in tea breeding programmes to generate progenies with a wide range of flavonol glycosides.

Kaempferol as Selective Human MAO-A Inhibitor: Analytical Detection in Calabrian Red Wines, Biological and Molecular Modeling Studies

The purpose of this work was to determine the kaempferol content in three red wines of Calabria, a southern Italian region with a great number of certified food products. Considering that wine cultivar, climate, and soil influence the qualitative and quantitative composition in flavonoids of Vitis vinifera L. berries, the three analyzed samples were taken from the 2013 vintage. Moreover, the Gaglioppo samples, with assigned Controlled Origin Denomination (DOC), were also investigated in the production of years 2008, 2010, and 2011. In addition to the analysis of kaempferol, which is present in higher concentration than in other Italian wines, in vitro assays were performed to evaluate, for the first time, the inhibition of the human monoamine oxidases (hMAO-A and hMAO-B). Molecular recognition studies were also carried out to provide insight into the binding mode of kaempferol and selectivity of inhibition of the hMAO-A isoform.

Regulation of flavonol content and composition in (Syrah×Pinot Noir) mature grapes: integration of transcriptional profiling and metabolic quantitative trait locus analyses

Flavonols are a ubiquitous class of flavonoids that accumulate preferentially in flowers and mature berries. Besides their photo-protective function, they play a fundamental role during winemaking, stabilizing the colour by co-pigmentation with anthocyanins and contributing to organoleptic characteristics. Although the general flavonol pathway has been genetically and biochemically elucidated, the genetic control of flavonol content and composition at harvest is still not clear. To this purpose, the grapes of 170 segregating F1 individuals from a 'Syrah'×'Pinot Noir' population were evaluated at the mature stage for the content of six flavonol aglycons in four seasons. Metabolic data in combination with genetic data enabled the identification of 16 mQTLs (metabolic quantitative trait loci). For the first time, major genetic control by the linkage group 2 (LG 2)/MYBA region on flavonol variation, in particular of tri-hydroxylated flavonols, is demonstrated. Moreover, seven regions specifically associated with the fine control of flavonol biosynthesis are identified. Gene expression profiling of two groups of individuals significantly divergent for their skin flavonol content identified a large set of differentially modulated transcripts. Among these, the transcripts coding for MYB and bZIP transcription factors, methyltranferases, and glucosyltranferases specific for flavonols, proteins, and factors belonging to the UV-B signalling pathway and co-localizing with the QTL regions are proposed as candidate genes for the fine regulation of flavonol content and composition in mature grapes.

Effect of Saccharomyces cerevisiae and Candida zemplinina on quercetin, vitisin A and hydroxytyrosol contents in Sangiovese wines

Quercetins, vitisin A and hydroxytyrosol are phenolic compounds possessing several positive properties to human health. This paper refers on the possible effects of two wine yeast species, Saccharomyces cerevisiae and Starmerella bacillaris (synonym Candida zemplinina) on the accumulation of these compounds in experimental Sangiovese wines. A single lot of Sangiovese grapes was fermented by S. cerevisiae alone or by sequential inoculum of C. zemplinina and S. cerevisiae under two aeration conditions. The accumulation of quercetin and its glycosides resulted only influenced by must aeration. However, yeast species occurring in the fermentative process affected the relative abundances among the different forms of quercetin. Vitisin A contents were higher in wines produced in the presence of C. zemplinina. Finally, higher concentrations of hydroxytyrosol and tyrosol were found in wines produced by S. cerevisiae alone under non-aerated condition. The fermentation of different Sangiovese grape musts carried out by the assayed S. cerevisiae strain pointed out that slow fermentation kinetics lead to higher levels of hydroxytyrosol and tyrosol. The study underlines the role of yeast species in determining the accumulation of bioactive compounds in Sangiovese wine.

Soil types effect on grape and wine composition in Helan Mountain area of Ningxia

Different soil types can significantly affect the composition of wine grapes and the final wine product. In this study, the effects of soil types on the composition of Cabernet Sauvignon grapes and wine produced in the Helan Mountains were evaluated. Three different representative soil types—aeolian, sierozem and irrigation silting soil were studied. The compositions of grapes and wines were measured, and in addition, the weights of 100-berry samples were determined. The grapes that grown on the aeolian and sierozem soils matured sooner than those grown on the irrigation silting soil. The highest sugar content, total soluble solids content, sugar to acid ratio and anthocyanin content were found in the grapes that grown on the aeolian soil. The wine produced from this soil had improved chroma and tone and higher-quality phenols. The grapes grown on the sierozem soil had the highest total phenol and tannin contents, which affected the wine composition. The grapes grown on the irrigation silting soil had higher acidities, but the remaining indices were lower. In addition, the grapes grown on the aeolian soil resulted in wines with better chroma and aroma. The sierozem soil was beneficial for the formation of wine tannins and phenols and significantly affected the wine composition. The quality of the grapes from the irrigation silting soil was relatively low, resulting in lower-quality wine.

Comparison and chemometric analysis of the phenolic compounds and organic acids composition of chinese wines

Characteristics of 106 wines from 5 major grape varieties and 3 typical geographic regions in China were investigated by means of profiling of organic acids and phenolic compounds analysis. An ultra-performance liquid chromatography method was developed and thus, large number of samples could be determined in a quick and reliable way. The results showed that different origins and varieties were characteristic of various profiles of organic acid and phenolic compounds. In order to investigate possible correlation between organic acids and phenolic compounds content and grape variety and/or geographical origin, analysis of variance and linear discriminant analysis (LDA) were conducted. A satisfactory LDA result for red wines according to geographic origin was obtained, in which the correct classification was 100% and the leave-one-out validation accuracy was 90%. The corresponding results of white wines were 91% and 86%, respectively. When LDA was processed, according to grape varieties, the proportionality of successfully classified wines was 96%, while the leave-one-out validation accuracy was 94%. The organic acids and phenolic compounds profiles were useful in the classification of Chinese wines according to grape variety and geographic origin.

Haematological and histopathological effects of apigenin, phloretin and myricetin based on uterotrophic assay in immature Wistar female albino rats

In this study, it is aimed to determine the histopathological and haematological effects of apigenin, phloretin and myricetin on Wistar immature female rats using Tier 2 of the uterotrophic assay. The female rats were divided into 17 groups with 6 rats in each group. There was a negative control group and positive control dose groups that contained 0.07 µg/kg/day, 0.7 µg/kg/day and 7 µg/kg/day of ethinyl estradiol (EE), 0.7 µg/kg/day 17α-ethinyl estradiol + 1 mg/kg/day tamoxifen and genistein. The other dose groups contain 1 mg/kg/day, 10 mg/kg/day and 100 mg/kg/day of apigenin, myricetin and phloretin. All chemicals had been given to Wistar immature female rats with oral gavage for three consecutive days. At the end of the study, blood samples were analysed for haematological parameters. Tissue samples that were taken from the liver, kidney, spleen and thyroid were histopathologically and histomorphometrically examined. There were no significant differences between oil control and other dose groups for glomerular histomorphometry. However, there were significant differences for thyroid histomorphometry. Especially, 10 and 100 mg/kg/day of phloretin dose groups had a significant increase in colloid surface area in thyroid compared with the 1 mg/kg/day of phloretin and oil control groups. Significant histopathological changes (congestion, degeneration, fibrosis and mononuclear cell infiltration) were noted in the tissue specimens obtained from the treatment groups compared with the control group. According to the results of the haematological analysis of the groups, especially the values of erythrocytes and haematocrit were increased significantly in most of the dose groups according to the oil control group.

Comparison of flavonoid compounds in the flavedo and juice of two pummelo cultivars (Citrus grandis L. Osbeck) from different cultivation regions in China

The objective of this study was to investigate the effect of different cultivation regions on the pattern and content of flavonoids in two pummelo cultivars (C. grandis L. Osbeck) in China. Results showed that similar patterns of flavonoids were observed in the flavedo or juice of each pummelo cultivar from these cultivation regions, whereas the individual flavonoid content showed unique characteristics. Naringin, the predominant flavanone glycoside, showed the highest content in both flavedo and juice of C. grandis "Guanximiyu" from the Pinghe of Fujian (FJ) cultivation region compared with the Dapu of Guangdong (GD) and Nanbu of Sichuan (SC) regions. However, its content in the flavedo of C. grandis "Shatianyu" from the Pingle of Guangxi (GX) was significantly lower than in the GD and SC regions. Vicenin-2 appeared to be the dominant flavone C-glycoside in the flavedo of both cultivars, and the lowest content was observed in the flavedo of C. grandis "Guanximiyu" from the SC region. However, C. grandis "Shatianyu" contained the highest content of vicenin-2 in the flavedo from SC region. Similarly, the predominant flavone O-glucoside, rhoifolin, showed the highest content in C. grandis "Guanximiyu" from the GD and FJ regions, whereas C. grandis "Shatianyu" in SC region showed the highest content of rhoifolin. Cluster analysis suggested that genotype played a primary role in determining the flavonoid profiles of pummelo cultivars, whereas regional differences significantly affected the flavonoid distribution of pummelo cultivars potentially via affecting the direction of flavonoid accumulation in pummelo.

Optimal information in authentication of food and beverages

Food and beverage authentication is the process by which food or beverages are verified as complying with their label descriptions ( Winterhalter, 2007 ). A common way to deal with an authentication process is to measure attributes, such as, groups of chemical compounds on samples of food, and then use these as input for a classification method. In many applications there may be several types of measurable attributes. An important problem thus consists of determining which of these would provide the best information, in the sense of achieving the highest possible classification accuracy at low cost. We approach the problem under a decision theoretic strategy, by framing it as the selection of an optimal test ( Geisser and Johnson, 1992 ) or as the optimal dichotomization of screening tests variables ( Wang and Geisser, 2005 ), where the ‘test’ is defined through a classification model applied to different groups of chemical compounds. The proposed methodology is motivated by data consisting of measurements of 19 chemical compounds (Anthocyanins, Organic Acids and Flavonols) on samples of Chilean red wines. The main goal is to determine the combination of chemical compounds that provides the best information for authentication of wine varieties, considering the losses associated to wrong decisions and the cost of the chemical analysis. The proposed methodology performs well on simulated data, where the best combination of responses is known beforehand.

Advanced knowledge of three important classes of grape phenolics: anthocyanins, stilbenes and flavonols

Grape is qualitatively and quantitatively very rich in polyphenols. In particular, anthocyanins, flavonols and stilbene derivatives play very important roles in plant metabolism, thanks to their peculiar characteristics. Anthocyanins are responsible for the color of red grapes and wines and confer organoleptic characteristics on the wine. They are used for chemotaxonomic studies and to evaluate the polyphenolic ripening stage of grape. They are natural colorants, have antioxidant, antimicrobial and anticarcinogenic activity, exert protective effects on the human cardiovascular system, and are used in the food and pharmaceutical industries. Stilbenes are vine phytoalexins present in grape berries and associated with the beneficial effects of drinking wine. The principal stilbene, resveratrol, is characterized by anticancer, antioxidant, anti-inflammatory and cardioprotective activity. Resveratrol dimers and oligomers also occur in grape, and are synthetized by the vine as active defenses against exogenous attack, or produced by extracellular enzymes released from pathogens in an attempt to eliminate undesirable toxic compounds. Flavonols are a ubiquitous class of flavonoids with photo-protection and copigmentation (together with anthocyanins) functions. The lack of expression of the enzyme flavonoid 3′,5′-hydroxylase in white grapes restricts the presence of these compounds to quercetin, kaempferol and isorhamnetin derivatives, whereas red grapes usually also contain myricetin, laricitrin and syringetin derivatives. In the last ten years, the technological development of analytical instrumentation, particularly mass spectrometry, has led to great improvements and further knowledge of the chemistry of these compounds. In this review, the biosynthesis and biological role of these grape polyphenols are briefly introduced, together with the latest knowledge of their chemistry.

Berry phenolics of grapevine under challenging environments

Plant phenolics have been for many years a theme of major scientific and applied interest. Grape berry phenolics contribute to organoleptic properties, color and protection against environmental challenges. Climate change has already caused significant warming in most grape-growing areas of the world, and the climatic conditions determine, to a large degree, the grape varieties that can be cultivated as well as wine quality. In particular, heat, drought and light/UV intensity severely affect phenolic metabolism and, thus, grape composition and development. In the variety Chardonnay, water stress increases the content of flavonols and decreases the expression of genes involved in biosynthesis of stilbene precursors. Also, polyphenolic profile is greatly dependent on genotype and environmental interactions. This review deals with the diversity and biosynthesis of phenolic compounds in the grape berry, from a general overview to a more detailed level, where the influence of environmental challenges on key phenolic metabolism pathways is approached. The full understanding of how and when specific phenolic compounds accumulate in the berry, and how the varietal grape berry metabolism responds to the environment is of utmost importance to adjust agricultural practices and thus, modify wine profile.

Dietary (poly)phenolics in human health: structures, bioavailability, and evidence of protective effects against chronic diseases

Human intervention trials have provided evidence for protective effects of various (poly)phenol-rich foods against chronic disease, including cardiovascular disease, neurodegeneration, and cancer. While there are considerable data suggesting benefits of (poly)phenol intake, conclusions regarding their preventive potential remain unresolved due to several limitations in existing studies. Bioactivity investigations using cell lines have made an extensive use of both (poly)phenolic aglycones and sugar conjugates, these being the typical forms that exist in planta, at concentrations in the low-μM-to-mM range. However, after ingestion, dietary (poly)phenolics appear in the circulatory system not as the parent compounds, but as phase II metabolites, and their presence in plasma after dietary intake rarely exceeds nM concentrations. Substantial quantities of both the parent compounds and their metabolites pass to the colon where they are degraded by the action of the local microbiota, giving rise principally to small phenolic acid and aromatic catabolites that are absorbed into the circulatory system. This comprehensive review describes the different groups of compounds that have been reported to be involved in human nutrition, their fate in the body as they pass through the gastrointestinal tract and are absorbed into the circulatory system, the evidence of their impact on human chronic diseases, and the possible mechanisms of action through which (poly)phenol metabolites and catabolites may exert these protective actions. It is concluded that better performed in vivo intervention and in vitro mechanistic studies are needed to fully understand how these molecules interact with human physiological and pathological processes.

Bioavailability of wine-derived phenolic compounds in humans: a review

Phenolic compounds are produced in the seeds and skins of grapes, and are transferred into wine during the fermentation process. Phenolic compounds can also be imparted into wine from maturation and storage in oak wood barrels after fermentation. The consumption of wine, an alcoholic beverage, has been observed in epidemiological studies to reduce the risk of cardiovascular disease and certain cancers, as well as diabetes and dementia, in a J-shaped relationship between amount consumed and level of risk. The bioactivity of wine primarily observed in vitro and ex vivo, may result from wine's relatively high content of phenolic compounds, which is similar to that observed in fruits and vegetables; a Mediterranean fruit and vegetable rich-diet is also associated with a reduced risk of cardiovascular disease and cancers. If the wine-derived phenolic compounds or their active metabolites are not absorbed in sufficient amounts and in a readily available form for cells, however, then they are less likely to have any significant in vivo activity. This review considers and discusses the available data to date on the bioavailability of the different wine-derived phenolic compounds in humans.

Effect of maturity on phenolics (phenolic acids and flavonoids) profile of strawberry cultivars and mulberry species from Pakistan

In this study, we investigated how the extent of ripeness affects the yield of extract, total phenolics, total flavonoids, individual flavonols and phenolic acids in strawberry and mulberry cultivars from Pakistan. In strawberry, the yield of extract (%), total phenolics (TPC) and total flavonoids (TFC) ranged from 8.5–53.3%, 491–1884 mg gallic acid equivalents (GAE)/100 g DW and 83–327 mg catechin equivalents (CE)/100 g DW, respectively. For the different species of mulberry the yield of extract (%), total phenolics and total flavonoids of 6.9–54.0%, 201–2287 mg GAE/100 g DW and 110–1021 mg CE/100 g DW, respectively, varied significantly as fruit maturity progressed. The amounts of individual flavonols and phenolic acid in selected berry fruits were analyzed by RP-HPLC. Among the flavonols, the content of myricetin was found to be high in Morus alba (88 mg/100 g DW), the amount of quercetin as high in Morus laevigata (145 mg/100 g DW) while kaempferol was highest in the Korona strawberry (98 mg/100 g DW) at fully ripened stage. Of the six phenolic acids detected, p-hydroxybenzoic and p-coumaric acid were the major compounds in the strawberry. M. laevigata and M. nigra contained p-coumaric acid and vanillic acid while M. macroura and M. alba contained p-hydroxy-benzoic acid and chlorogenic acid as the major phenolic acids. Overall, a trend to an increase in the percentage of extraction yield, TPC, TFC, flavonols and phenolic acids was observed as maturity progressed from un-ripened to fully-ripened stages.

Selective apoptotic effects of piceatannol and myricetin in human cancer cells

Numerous studies have shown the potential of dietary polyphenols as anticarcinogenic agents. The aim of the present study was to evaluate the apoptotic effects of piceatannol and myricetin, naturally occurring polyphenols in red wine, alone or in combination, in two human cell lines: HL-60 (leukemia) and HepG2 (hepatoma). Apoptotic cells were identified by chromatin condensation, poly(ADP-ribose) polymerase cleavage and flow cytometry analysis. Results from TUNEL assay showed that piceatannol or myricetin alone induced apoptotic cell death in a concentration- and time-dependent manners in HL-60 cells. Furthermore, in combined treatment the percentage of apoptotic HL-60 cells was significantly higher. Nevertheless, the percentage of TUNEL positive HepG2 cells only was significant after piceatannol treatment and in combined treatment was even lower than in cells treated with piceatannol alone. Moreover, we also studied the relative reactive oxygen species (ROS) production. Our results indicate that apoptosis induced by piceatannol or myricetin occurs through an ROS-independent cell death pathway. In conclusion, piceatannol and myricetin synergistically induced apoptosis in HL-60 cells but not in HepG2 cells. These findings suggest that the potential anticarcinogenic properties of dietary polyphenols depend largely on the cell line used. The relevance of these data needs to be verified in human epidemiological studies.