Antioxidants (Nov 2022)

Structural Effects on the Antioxidant Properties of Amino Acid Betaxanthins

  • Larissa Cerrato Esteves,
  • Caroline Oliveira Machado,
  • Letícia Christina Pires Gonçalves,
  • Victor Fernandes Cavalcante,
  • Guilherme Obeid,
  • Thiago Carita Correra,
  • Erick Leite Bastos

DOI
https://doi.org/10.3390/antiox11112259
Journal volume & issue
Vol. 11, no. 11
p. 2259

Abstract

Read online

Betaxanthins are natural products with high antioxidant and anti-inflammatory properties. Here, we describe the semisynthesis of twenty-one betaxanthins derived from proteinogenic amino acids, including the elusive betaxanthin of l-cysteine and two betaxanthins derived from l-lysine, and rationalize their antioxidant properties in mechanistic terms. The antioxidant capacity and redox potential of these betaxanthins were compared to those of model betaxanthins derived from dopamine, l-DOPA (L-3,4-dihydroxyphenylalanine), and pyrrolidine and structure–property relationships were established by using matched molecular pair analysis and a model developed using a genetic algorithm. Either a phenol or indole moiety enhance the antioxidant capacity of betaxanthins, which is overall much higher than that of their amino acid precursors and standard antioxidants, except for the cysteine-betaxanthin. The one-electron oxidation of amino acid betaxanthins produces radicals stabilized in multiple centers, as demonstrated by quantum chemical calculations.

Keywords