Flavonoids: hemisynthesis, reactivity, characterization and free radical scavenging activity.

نویسندگان

  • Nour-Eddine Es-Safi
  • Souhila Ghidouche
  • Paul Henri Ducrot
چکیده

Phenolic compounds form one of the main classes of secondary metabolites. They display a large range of structures and they are responsible for the major organoleptic characteristics of plant-derived-foods and beverages, particularly color and taste properties and they also contribute to the nutritional qualities of fruits and vegetables. Phenolic compounds are also highly unstable compounds which undergo numerous enzymatic and chemical reactions during postharvest food storage and processing thus adding to the complexity of plant polyphenol composition. Among these compounds flavonoids constitute one of the most ubiquitous groups of all plant phenolics. Owing to their importance in food organoleptic properties and in human health, a better understanding of their structures, their reactivity and chemical properties in addition to the mechanisms generating them appears essential to predict and control food quality. The purpose of this work is an overview of our findings concerning the hemisynthesis, the reactivity and the enzymatic oxidation of some flavonoids and shed light on the mechanisms involved in some of these processes and the structures of the resulting products. The free radical scavenging activity of some of the synthesized compounds is also presented and a structure-activity relationship is discussed. The first part of this review concerns the synthesis and structural characterization of modified monomeric flavanols. The use of these compounds as precursor for the preparation of natural and modified dimeric procyanidin derivatives was then explored through different coupling reactions. The full characterization of the synthesized compounds was achieved by concerted use of NMR and ESI-MS techniques. The free radical scavenging activity of some of the synthesized compounds was investigated. The second part of this review concerns the enzymatic oxidation of several flavonols by Trametes versicolor laccase. Most of the major oxidation products have been isolated as pure compounds and their structures unambiguously established through spectroscopic methods. Correlation between the structure of the oxidation product and the substitution pattern of the starting materials allows mechanistic features of this transformation to be elucidated.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Free Radical Scavenging Activity of Some Plants Available in Malaysia

The present study was carried out to determine the free radical scavenging properties of some plants, found in Malaysia. The air-dried leaves of each plant (20 g) were soaked in distilled water (1:20; w/v) for 72 h at room temperature. Collected supernatants were tested for free radical scavenging activity against the DPPH and superoxide anion radical scavenging assays. All extracts were found ...

متن کامل

Flavonoid Contents and Free Radical Scavenging Activity of Extracts from Leaves, Stems, Rachis and Roots of Dryopteris erythrosora

The present study was designed to explore the flavonoid contents and the radical scavenging activities of 50% ethanol extracts of leaves, stems, rachis and roots of Dryopteris erythrosora. The total flavonoid contents in various parts were determined as: stems > roots > rachis > leaves. All extracts from different parts of D. erythrosora showed strong bioactivities. The DPPH free radical scaven...

متن کامل

Flavonoid Contents and Free Radical Scavenging Activity of Extracts from Leaves, Stems, Rachis and Roots of Dryopteris erythrosora

The present study was designed to explore the flavonoid contents and the radical scavenging activities of 50% ethanol extracts of leaves, stems, rachis and roots of Dryopteris erythrosora. The total flavonoid contents in various parts were determined as: stems > roots > rachis > leaves. All extracts from different parts of D. erythrosora showed strong bioactivities. The DPPH free radical scaven...

متن کامل

FREE RADICAL SCAVENGING ACTIVITY OF FLAVONOID CONTAINING LEAF EXTRACTS OF Stevia rebaudiana Bert

To evaluate the free radical scavenging activity of flavonoids containing extracts of Stevia leaf. Alcoholic. Successive butanolic and alcoholic extracts of leaves were examined for free radical scavenging activity using BHT (tert-butylhydroxytolune) as a positive control by in vitro models. Successive alcoholic extract showed remarkable free radical scavenging activity. The IC(50) was found to...

متن کامل

In vitro Antioxidant and Free Radical Scavenging Activity of Extracts of Rosa damascena Flower Petals

Introduction: Rosa damascena mill L., well-known as Rose, has numerous pharmacological properties including antioxidant, antitussive, relaxant effect on tracheal chains, hypnotic, antibacterial and anti-HIV. Objective: The objective of the present study was to evaluate antioxidant and free radical scavenging activity of various extracts of Rose flower petals. Methods: Chloroform, acetone, ethan...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Molecules

دوره 12 9  شماره 

صفحات  -

تاریخ انتشار 2007