Antioxidant activity of olive phenols and other dietary phenols in model gastric conditions: Scavenging of the free radical DPPH and inhibition of the haem-induced peroxidation of linoleic acid. (15th December 2016)

• Record Type: Journal Article
• Authors: Achat, Sabiha; Rakotomanomana, Njara; Madani, Khodir; Dangles, Olivier
• Is Part Of: Food chemistry. Volume 213(2016)
• Page Start: 135
• Page End: 142
• Publication Date: 2016-12-15
• Subjects: Phenols -- Olive -- Antioxidant -- DPPH -- Metmyoglobin -- Lipid peroxidation -- Haem; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2016.06.076
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: Oleuropein and hydroxytyrosol as antioxidants in mildly acidic micelle solution. Olive phenols are efficient radical scavengers (high rate constant & stoichiometry). Olive phenols rapidly reduce hypervalent heme iron. Olive phenols alone are only moderate inhibitors of heme-induced lipid peroxidation. Synergy between hydroxytyrosol and α-tocopherol in the inhibition. Abstract: The antioxidant activity of dietary phenols in humans (direct reduction of radicals and other highly oxidizing species) could be largely restricted to fighting postprandial oxidative stress in the gastric compartment. Hence, the development of chemical tests simply modelling this situation is pertinent. In this work, the antioxidant properties of the olive phenols hydroxytyrosol and oleuropein are investigated in pH 5–6 micellar solutions through the reduction of the DPPH radical and the inhibition of the metmyoglobin-induced peroxidation of linoleic acid. In the first test, hydroxytyrosol and oleuropein proved as efficient as common polyphenols and their reactivity was only moderately affected by β-cyclodextrin and bovine serum albumin, taken as models of food macromolecules. In the second test, hydroxytyrosol and oleuropein by themselves came up as relatively weak inhibitors, despite their efficiency at reducing hypervalent haem iron. However, hydroxytyrosol was able to act in synergy with the typical chain-breaking antioxidant α-tocopherol.