The antioxidant properties of theaflavins and their gallate esters — radical scavengers or metal chelators?

FEBS Letters

Rice-Evans, Catherine²  Castelluccio, Cinzia²  Miller, Nicholas J.²  Tijburg, Lilian¹ 

[1] Unilever Research Laboratories, Vlaardingen, The Netherlands;International Antioxidant Research Centre, UMDS - Guy's Hospital, London SE1 9RT, UK

关键词: Theaflavin;    Black tea;    Metal chelator;    Hydroxyl radical scavenger;    Total antioxidant activity;    Oxidized LDL;   

DOI  :  10.1016/0014-5793(96)00780-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The antioxidant properties of theaflavins and their gallate esters were studied by investigating their abilities to scavenge free radicals in the aqueous and lipophilic phases. The total relative antioxidant activities in the aqueous phase were assessed by measuring their direct ABTS^·+ radical scavenging abilities, and by their efficacies in inhibiting the degradation of deoxyribose induced by iron. The propensities for enhancing the resistance of LDL to oxidation mediated by Cu²⁺ were also measured. The results show that the hierarchy of reactivity of these compounds as antioxidants is: theaflavin digallate > 3′-monogallate=3-monogallate > theaflavin. Spectroscopic studies show that all the compounds chelate iron and copper; enhanced absorbance in the visible region is observed in the case of the iron-digallate complex, but not with copper.

【 授权许可】

Unknown