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

Folch-Cano, C; Olea Azar C.; Jullian C.; Speisky H.

Keywords: stability, oxygen, solutions, antioxidants, hydrogen, conductivity, complex, storage, capacity, atoms, structure, dyes, antioxidant, catechin, species, stoichiometry, phenols, tea, inclusion, constants, assays, vitamins, data, equipment, red, cyclodextrins, readers, cds, activities, thermal, orac-fl, gallate, Reactive, epigallocatechin, aqueous, microplate, pyrogallol, Anti-oxidant, Multidetection, ORAC-PGR


Inclusion complexes of native and two derivatizated ?-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 ?CDs was studied using Multi-Detection Microplate Reader. The antioxidant reactivity mainly depends of the inclusion modes of the TC in the ?CDs 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 ?CDs cavity. © 2010 Elsevier Ltd.

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Volumen: 43
Número: 8
Editorial: Elsevier
Fecha de publicación: 2010
Página de inicio: 2039
Página final: 2044