Antioxidant activity of flavonoids: efficiency of singlet oxygen (1 delta g) quenching
| Autor: | Marie-Thérèse Maurette, Cécile Tournaire, Esther Oliveros, Irena Beck, André M. Braun, Sylvie Croux, Michel Hocquaux |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
chemistry.chemical_classification
Flavonoids Radiation Quenching (fluorescence) Radiological and Ultrasound Technology Double bond Singlet Oxygen Singlet oxygen Photochemistry Biophysics Free Radical Scavengers Antioxidants Oxygen chemistry.chemical_compound Kinetics Structure-Activity Relationship Flavonols Reaction rate constant chemistry Radiology Nuclear Medicine and imaging Reactivity (chemistry) Singlet state Flavanone |
| Zdroj: | Journal of photochemistry and photobiology. B, Biology. 19(3) |
| ISSN: | 1011-1344 |
| Popis: | Flavonoids, polyphenolic pigments widely present in plants, have been reported to act as scavengers of various oxidizing species. However, most often an overall antioxidant effect was measured. In this paper we report the results of a systematic study of the reactivity of 13 selected flavonoids (from the flavonol, flavone, flavanone and flavane families) with singlet oxygen (1O2(1 delta g)) in order to establish a structure-activity relationship. The rate constants of the chemical reaction of these flavonoids with 1O2(k r) and their rate constants of 1O2 physical quenching (kq) have been determined by kinetic measurements and near-IR singlet oxygen luminescence. The efficiency of the physical quenching is mainly controlled by the presence of a catechol moiety on ring B, whereas the structure of ring C (particularly the presence of a hydroxyl group activating the double bond) is the main factor determining the efficiency of the chemical reactivity of these compounds with 1O2. The total reactivity factor determining the efficiency of the chemical reactivity of these compounds with 1O2. The total reactivity scale is dominated by kq, which is in general higher than kr. (+)-Catechin is the most efficient quencher of the series. |
| Databáze: | OpenAIRE |
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