Estudio químico y de actividad antioxidante de la Bauhinia guinensis var. kuntiana Aubl.

Antioxidants are substances of great interest, considered as protectors of biological systems against oxidation, which cause degenerative processes due to the presence of free radicals. The evaluation of the antioxidant activity of the plant species was carried out by applying two methods: the chemical method, by neutralizing the free radical 2,2-diphenyl-1-picrylhydracil (DPPH) and the electrochemical method, using cyclic voltammetry. From the separation, guided by the antioxidant activity, of the AE fraction of Bauhinia guianensis var. kuntiana Aubl., the compound with the highest activity, 5,7,3 ', 4'-tetrahydroxyflavanone (eriodictyol) with mp = 216 ° C, was isolated, which has been identified through its IR, UV, MS, 1H NMR spectra, NMR 13C, 1H-1H COZY and 1H-13C HETCOR. The isolated flavonoid eriodictyol presented the highest antioxidant activity, 90.42% at a concentration of 10 µg / mL and an oxidation potential at pa1 0.206 V. The value determined for its EC50 was 1.81 µg / mL , which indicates that at a very low concentration it has good antioxidant activity and is comparable with rutin and quercetin standards. The relationship between structure - activity - redox potential of the active principle responsible for the antioxidant activity in the species was found. The catechol group (two adjacent -OH) in the compound is responsible for the higher antioxidant activity at a lower oxidation potential.