Protective effect of phenolic compounds on carbonyl-amine reactions produced by lipid-derived reactive carbonyls

Abstract

The degradation of phenylalanine initiated by 2-pentenal, 2,4-heptadienal, 4-oxo-2-pentenal, 4,5-epoxy-2-heptenal, or 4,5-epoxy-2-decenal in the presence of phenolic compounds was studied to determine the structure-activity relationship of phenolic compounds on the protection of amino compounds against modifications produced by lipid-derived carbonyls. The obtained results showed that flavan-3-ols were the most efficient phenolic compounds followed by single m-diphenols. The effectiveness of these compounds was found to be related to their ability to trap rapidly the carbonyl compound, avoiding in this way the reaction of the carbonyl compound with the amino acid. The ability of flavan-3-ols for this reaction is suggested to be related to the high electronic density existing in some of the aromatic carbons of their ring A. This is the first report showing that carbonyl-phenol reactions involving lipid-derived reactive carbonyls can be produced more rapidly than carbonyl-amine reactions, therefore providing a satisfactory protection of amino compounds.

Phenolic trapping of lipid oxidation products 4-oxo-2-alkenals

“…Previous research has shown that most of these ,-unsaturated aldehydes are trapped by phenolic compounds, also under normal cooking conditions (Zamora, Aguilar, Granvogl, & Hidalgo, 2016), and this has been suggested to constitute a protective mechanism of phenolic compounds against the toxicity of these lipid oxidation products . Thus, for example, 2-alkenals suffer the addition of phenolic compounds to produce 2H-chromenols, chromandiols, chromanols, and dihydropyrano[3,2-g]chromenes , and 4,5-epoxy-2-alkenals are rapidly transformed into 1,3a,4,9b-tetrahydro-2H-furo[2,3-c]chromene-2, 7diols and 3,4,4a,9a-tetrahydro-1H-pyrano[3,4-b]benzofuran-3,7-diols (Hidalgo, Delgado, & Zamora, 2017;. However, the potential ability of phenolic compounds to trap 4-oxo-2-alkenals has not been described so far.…”

Epoxyalkenal-trapping ability of phenolic compounds

“…Epoxyalkenals are minor lipid oxidation products, but they react rapidly with amino acids, aminophospholipids and proteins producing their rapid degradation at the same time that non-enzymatic browning is produced by means of carbonyl-amine reactions (Hidalgo & Zamora, 1993). However, previous studies have pointed out that they are rapidly scavenged in the presence of certain phenolic compounds, which included single m-diphenols and flavan-3-ols (Hidalgo, Delgado, & Zamora, 2017).…”

“…As model phenolic compounds, only simple m-diphenols were employed, namely 2methylresorcinol and 2,5-dimethylresorcinol. These phenolic compounds were selected because carbonyl-phenol adducts are formed mainly with phenolic compounds having two hydroxyl groups at metha positions (Salazar, Arámbula-Villa, Hidalgo, & Zamora, 2014), and simple m-diphenols are efficient epoxyalkenal-trapping agents (Hidalgo, Delgado, & Zamora, 2017). Alkadienals, phenolic compounds and all other chemicals employed in this study were purchased from Sigma-Aldrich (St. Louis, MO), Fluka (Buchs, Switzerland), or Merck (Darmstadt, Germany) and were either analytical grade or the highest available grade.…”

“…The reaction between epoxyalkenals and phenolic compounds is very fast and produces a complex mixture of compounds (Hidalgo, Delgado, & Zamora, 2017).…”

“…Thus, some of these lipid-derived carbonyl compounds have been shown to be trapped by phenolic compounds in food products at the same time that they are being produced (Zamora, Aguilar, Granvogl, & Hidalgo, 2016). In addition, other highly reactive lipid oxidation products, namely 4,5-epoxy-2alkenals, have been shown to be trapped by phenolic compounds with preference to other lipid oxidation products and this reaction is fast enough to prevent the production of the competitive carbonyl-amine reactions (Hidalgo, Delgado, & Zamora, 2017).…”