Stability of ferric complexes with 3-hydroxyflavone (flavonol), 5,7-dihydroxyflavone (chrysin), and 3',4'-dihydroxyflavone.

摘要: The acid dissociation and ferric stability constants for complexation by the flavonoids 3-hydroxyflavone (flavonol), 5,7-dihydroxyflavone (chrysin), 3',4'-dihydroxyflavone in 50:50 (v/v) ethanol/water are determined pH potentiometric spectrophotometric titrations linear least-squares curve-fitting program Hyperquad. Over entire range of reagent concentrations spanning titration experiments, stoichiometry iron-flavonoid complex formation was 1:1 all three examined. were chosen their hydroxy substitution pattern, with each possessing one most commonly suggested sites metal binding flavonoids. On basis calculated constants, intraflavonoid-binding site competition is illustrated as a function via speciation curves. curves indicate that comprised 3',4'-hydroxy substitutions, catecholic site, influential at physiological 7.4. possibility antioxidant activity flavonoid chelation iron presence other competitive complexing agents demonstrated through additional calculations.