Search results for "flavonol"

CCDC 261930: Experimental Crystal Structure Determination

2006

Related Article: F.B.A.El Amrani, L.Perello, J.A.Real, M.Gonzalez-Alvarez, G.Alzuet, J.Borras, S.Garcia-Granda, J.Montejo-Bernardo|2006|J.Inorg.Biochem.|100|1208|doi:10.1016/j.jinorgbio.2006.01.036

The influence of two different pH levels on the antioxidant properties of flavonols, flavan-3-ols, phenolic acids and aldehyde compounds analysed in …

2011

Abstract The aim of this study is evaluate either the antioxidant or pro-oxidant behaviour of some typical polyphenolic compounds of red wine, to investigate the influence of two different pH levels on the antioxidant properties and to clarify their activity–structure relationship. The antioxidant activity of compounds in hydrophilic solutions at pH 3.5 and pH 7.4 were measured by a competition kinetic test, based on the crocin bleaching. The position and the number of substitution groups influence the magnitude of the antioxidant activity of the polyphenolic compounds, but their antioxidant properties are also strongly influenced by the pH conditions. Increasing the pH, a considerable incr…

Effect of leaf removal and ripening stage on the content of quercetin glycosides in Sangiovese grapes

2021

Quercetin haze has been observed over the last few years in some aged Sangiovese wines. This problem could be due to an excess of the quercetin in the wine. Leaf removal increases the exposition of clusters to sunlight, which may enhance flavonol synthesis in the grapes. In this study, we evaluated the dynamics related to extractable flavonols in grapes grown in three usually defoliated Vitis vinifera (L.) cv. Sangiovese vineyards, whose wines showed quercetin precipitates. The particular structure of the vineyards in which the leaf removal experiments were carried out allowed the influence of vineyard, biotype and rootstock on grape flavonol contents at mid-maturation and technological mat…

Flavonols and flavan-3-ols as modulators of xanthine oxidase and manganese superoxide dismutase activity.

2014

Experiments were performed to assess the dose-dependent effects of quercetin, kaempferol, (+) catechin, and (-) epicatechin on superoxide radical production through the modulation of manganese superoxide dismutase and xanthine oxidase activities. The experiments were carried out at flavanoid concentrations ranging from 1 µM to 100 µM. This investigation highlighted that flavonols induced opposite effects on superoxide radical production at different doses, i.e. pro-oxidant at the highest concentration (100 µM) and anti-oxidant at the lowest concentration (1 µM). Similar behaviors were observed for xanthine oxidase with flavan-3ols. The diastereoisomer (the catechin) acted as a stronger radi…

2018

Whisky can be described as a complex matrix integrating the chemical history from the fermented cereals, the wooden barrels, the specific distillery processes, aging, and environmental factors. In this study, using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS), we analyzed 150 whisky samples from 49 different distilleries, 7 countries, and ranging from 1 day new make spirit to 43 years of maturation with different types of barrel. Chemometrics revealed the unexpected impact of the wood history on the distillate's composition during barrel aging, regardless of the whisky origin. Flavonols, ol…

Phenolic metabolites from 5,000-year-old coprolites of Myotragus balearicus, an extinct insular bovid

2020

Abstract To date, the identification of polyphenols in the archaeological and palaeontological record has been limited. Here, we demonstrate for the first time the presence of flavonoid and phenolic metabolites from non-mineralised coprolites belonging to a non-human mammal species. Myotragus balearicus is the last species of a bovid lineage that became extinct during the Holocene in the western Mediterranean basin. In this work, we characterize the phenolic metabolites of M. balearicus coprolites for the first time. The chemical analysis of coprolites revealed the presence of flavonoids, such as flavones and flavonols. Moreover, the detection of conjugates of hydroxyphenylvaleric, hydroxyp…

New phenolics, cytotoxicity and chemosystematic significance of Atriplex semibaccata

2019

Abstract The chemical characterization of the 70% hydromethanolic extract of Atriplex semibaccata (family: Chenopodiaceae) afforded a new methoxylated flavonol triglycoside, atrisemibaccatoside A (1), and a new lignanamide, (N-[(E)-m-hydroxycinnamoyl]tyramine (7), as well as, five known flavonols (2–6) and two lignanamides (8–9). The structures of the isolated compounds were established depending upon LR&HR-FAB-MS, 1D and 2D NMR spectroscopic analyses. The cytotoxic activity of the isolated compounds (1–4, and 7–9) was investigated. Compounds 7, 8 and 9 weakly inhibited the proliferation of leukemia CCRF-CEM cells with IC50 values of 78.5, 46.3, and 71.2 μg/ml, respectively, and exhibited n…

Green extraction approach for the recovery of polyphenols from Croatian olive leaves (Olea europea)

2017

Abstract Pressurized liquid extraction (PLE) is shown as an innovative green technology for the effective extraction of the various phytochemicals from food by-products, therefore the aims of this study were to evaluate the application of PLE to engineer green extracts of Croatian olive leaves ( Olea europaea , cv. Oblica) for potential industrial production (functional foods/pharmaceuticals). PLE was conducted under various cycle numbers (1, 2), temperature (60, 80, 100 °C) and static times (5, 10, 15 min). Obtained extracts were characterized in terms of: (i) total polyphenols (TP); (ii) total flavonoids (TF); hydroxycinnamic acids (HCA); and (iv) flavonols (FLA). Response surface methodo…

Phytochemical constituents and chemosystematic significance of Pulicaria jaubertii E.Gamal-Eldin (Asteraceae)

2018

Abstract The chemical characterization of methylene chloride/methanol (1:1) extract of the air-dried whole medicinal plant, Pulicaria jaubertii E. Gamal-Eldin, led to isolation and identification of two new hydroquinone compounds; 2-(2-acetoxy propyl), 5-methyl hydroquinone (1) and 2-(2-hydroxy propyl), 5-methyl hydroquinone-4-O-β-D-glucopyranoside (2), four known flavonols (3-6) and 7 known dihydroflavonols (7-13). The structures were established depending upon comprehensive analysis of the NMR, IR and HR/EI-MS data. Herein, compounds 6, and 10-13 were isolated for the first time from this plant. The chemotaxonomic significance of the isolated flavonoids from P. jaubertii comparing with th…

The impact of chocolate on cardiovascular health

2011

Cardiovascular disease is the leading determinant of mortality and morbidity in women. Functional foods are attracting interest as potential regulators of the susceptibility to disease. Supported by epidemiological evidence, chocolate has emerged as a possible modulator of cardiovascular risk. Chocolate, or cocoa as the natural source, contains flavanols, a subclass of flavonoids. The latter years have witnessed an increasing number of experimental and clinical studies that suggest a protective effect of chocolate against atherogenesis. Oxidative stress, inflammation, and endothelial function define three biological mechanisms that have shown sensitivity to chocolate. Moreover, the consumpt…