Potentiometric and UV-Vis spectrophotometric titrations for evaluation of the antioxidant capacity of chicoric acid.

ABSTRACT: The antioxidant capacity (AOC) of chicoric acid (ChA, the main antioxidant component of Echinacea) or an ethanol/water-extract of Echinacea flowers was determined by potentiometric and UV-Vis absorption spectrophotometric titrations with ABTS˙⁺ radical cations as the oxidizing probe. The potentiometric and spectrophotometric titration results agreed well with each other. The trolox-equivalent antioxidant capacity (TEAC) of ChA was found to be 5.00 ± 0.07 (potentiometry) and 4.81 ± 0.06 (spectrophotometry) at pH 7.4, and the TEAC value has been proven to be actually equal to the ratio of the stoichiometric ratio of the ABTS˙⁺-ChA redox reaction to that of the ABTS˙⁺-trolox redox reaction. The TEAC of the ethanol/water-extract of Echinacea

SUBMITTER: Yi H 

PROVIDER: S-EPMC9050702 | biostudies-literature | 2020 Mar

REPOSITORIES: biostudies-literature