Search results for "Polyphenol"

Concentration dependent effects of commonly used pesticides on activation versus inhibition of the quince (Cydonia Oblonga) polyphenol oxidase

2009

Polyphenol oxidase (PPO) catalyzes the oxidation of o-diphenols to their respective quinones which undergo autopolymerization and form dark pigments. The interaction of PPO with various substrates and effectors remains the focus of intensive investigations due to the enzyme's key role in pigments biosynthesis including animal melanogenesis and fruit/fungi enzymatic browning. In this study, the effect of a range of commonly used pesticides on the enzyme activity has been evaluated using the purified quince (Cydonia oblonga Miller) PPO. The biochemical analysis showed that, in the presence of high pesticide concentrations, the enzyme was competitively inhibited, particularly with benomyl, car…

Influence of Laccase and Tyrosinase on the Antioxidant Capacity of Selected Phenolic Compounds on Human Cell Lines

2015

Polyphenolic compounds affect the color, odor and taste of numerous food products of plant origin. In addition to the visual and gustatory properties, they serve as radical scavengers and have antioxidant effects. Polyphenols, especially resveratrol in red wine, have gained increasing scientific and public interest due to their presumptive beneficial impact on human health. Enzymatic oxidation of phenolic compounds takes place under the influence of polyphenol oxidases (PPO), including tyrosinase and laccase. Several studies have demonstrated the radical scavenger effect of plants, food products and individual polyphenols in vitro, but, apart from resveratrol, such impact has not been prove…

Wild Sicilian Rosemary: Phytochemical and Morphological Screening and Antioxidant Activity Evaluation of Extracts and Essential Oils

2015

To identify the best biotypes, an extensive survey of Sicilian wild rosemary was carried out by collecting 57 samples from various sites, followed by taxonomic characterization from an agronomic perspective. All the biotypes collected were classified as Rosmarinus officinalis L. A cluster analysis based on the morphological characteristics of the plants allowed the division of the biotypes into seven main groups, although the characteristics examined were found to be highly similar and not area-dependent. Moreover, all samples were analyzed for their phytochemical content, applying an extraction protocol to obtain the nonvolatile components and hydrodistillation to collect the essential oil…

Influence of yeast strain on ochratoxin A content during fermentation of white and and red must

2006

A Two-Year Bio-Agronomic and Chemotaxonomic Evaluation of Wild Sicilian Myrtle (Myrtus communis L.) Berries and Leaves.

2019

A collection of nine Myrtus communis samples from different localities of Sicily was evaluated. Morphological traits and production characteristics have been chosen as parameters to arrange the samples into homogeneous groups and to identify the best biotypes for possible future agro-industrial exploitation. The plant material has been subjected to taxonomic characterization from biometric and phytochemical perspectives. Myrtle berries and leaves have been analyzed for their content in metabolites, applying a cascade extraction protocol for M. communis leaves and a single hydroalcoholic extraction for berries, whereas hydrodistillation procedures have been applied to obtain the essential oi…

Electrochemical tomato (Solanum lycopersicum L.) characterisation using contact probe in situ voltammetr

2015

[EN] An in situ electrochemical contact probe methodology for characterising tomato samples is proposed. It is based on the record of the voltammetric response of antioxidant compounds when glassy carbon electrodes are inserted into the pericarp of fresh tomato specimens cut in half. The absence of pretreatment and in situ sampling avoid sample contamination and the oxidation of air-sensitive compounds thus increasing the representativity of the analytical data relative to conventional electrochemical analysis. Characteristic voltammetric responses recorded for such compounds, including rutin, chlorogenic acid, naringenin, naringenin chalcone and ascorbic acid have been obtained. A positive…

Chronic renal failure: oxidative stress, endothelial dysfunction and wine.

2004

Atherosclerosis development is accelerated in chronic renal failure (CRF) and is the major cause of death in this clinical condition. An increased oxidative stress and an endothelial dysfunction, with their complex interrelationships, are relevant aspects of atherogenesis in CRF patients and might be targets for treatment. Many studies have underlined the cardiovascular protection provided by a moderate wine consumption. This beneficial effect is due to both alcohol and nonalcoholic components of wine including several phenolic molecules such as quercetin and resveratrol. Wine polyphenols have antioxidant properties and favorably influence endothelial function, in particular by stimulating …

Two-carbon metabolites, polyphenols and vitamins influence yeast chronological life span in winemaking conditions

2012

Abstract Background Viability in a non dividing state is referred to as chronological life span (CLS). Most grape juice fermentation happens when Saccharomyces cerevisiae yeast cells have stopped dividing; therefore, CLS is an important factor toward winemaking success. Results We have studied both the physical and chemical determinants influencing yeast CLS. Low pH and heat shorten the maximum wine yeast life span, while hyperosmotic shock extends it. Ethanol plays an important negative role in aging under winemaking conditions, but additional metabolites produced by fermentative metabolism, such as acetaldehyde and acetate, have also a strong impact on longevity. Grape polyphenols quercet…

Total Nut, Tree Nut, and Peanut Consumption and Metabolic Status in Southern Italian Adults.

2021

Background: Nut consumption has been associated with cardio-metabolic health benefits. However, studies conducted in the Southern Italian population, where adherence to the Mediterranean diet has been reported being relatively high, are rather scarce. The aim of this study was to test the association between consumption of total and specific types of nuts and metabolic status among adults living in Sicily, Southern Italy. Methods: Demographic and dietary characteristics of 2044 adults living in Southern Italy were analyzed. Multivariate logistic regression analyses were performed to calculate odds ratios (ORs) and 95% confidence intervals (CIs) of the association between nut consumption and…

A preliminary study of presence of resveratrol in skins and pulps of European and Japanese plum cultivars

2012

BACKGROUND: Resveratrol is a polyphenol with health properties being mainly present in the skins of several foods. However, any study has been carried out to analyze the presence of this stilbene in the plum fruit from the genus Prunus in European and Japanese cultivars. RESULTS: The analysis of resveratrol from the skin in different cultivars of plums from Spanish markets with liquid chromatography coupled to ultraviolet (LC-UV) detector with subsequent confirmation by LC-MS/MS has been demonstrated that contents of this compound in plums ranged from 0.1 to 6.2 µg/g. CONCLUSIONS: Values of resveratrol in European plum cultivars is higher than in Japanese cultivars. Copyright © 2012 Society…