Antioxidant activity of inclusion complexes of tea catechins with β-cyclodextrins by ORAC assays

• Published in: Food research international Vol. 43; no. 8; pp. 2039 - 2044
• Main Authors: Folch-Cano, C., Jullian, C., Speisky, H., Olea-Azar, C.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.10.2010; Elsevier
• Subjects: Antioxidants; Biological and medical sciences; Coffee, tea and other stimulative beverage industries; Food industries; Fundamental and applied biological sciences. Psychology; ORAC-FL; ORAC-PGR; Tea catechins; β-cyclodextrins; Antioxidants; β-cyclodextrins; Tea catechins; ORAC-FL; ORAC-PGR; Flavanol; Catechin; Inclusion; Antioxidant; Flavonoid; Tea; Polyphenol; Cyclodextrin
• ISSN: 0963-9969; 1873-7145
• DOI: 10.1016/j.foodres.2010.06.006

Inclusion complexes of native and two derivatizated β-cyclodextrins with some tea catechins (TCs) like catechin (C), epigallocatechin gallate (EGCG) and gallocatechin gallate (GCG). The stoichiometry of TC complexes was determined and in all cases was 1:1. Stability constants were determined and their antioxidant capacity against reactive oxygen species (ROS) studied by means of the ORAC-fluorescein (ORAC-FL) and the ORAC-pyrogallol red (ORAC-PGR) assay. The antioxidant capacity of these TC in aqueous solution in the absence and presence of βCDs was studied using Multi-Detection Microplate Reader. The antioxidant reactivity mainly depends of the inclusion modes of the TC in the βCDs cavity. The difference between ORAC-PGR values for the same TC show that the inclusion structures should be different, maybe leading the same number of hydrogen atoms exposed (ORAC-FL values) outside or in the borders of βCDs cavity.