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Almond skin polyphenols scavenge DPPH, HOCl, ONOO‐, and O2‐. radicals and enhance quinone reductase
Author(s) -
Chen ChungYen,
Hamel Kendra,
Blumberg Jeffrey B.
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a362-b
Subject(s) - chemistry , antioxidant , gallic acid , dpph , ec50 , polyphenol , ascorbic acid , radical , reductase , biochemistry , food science , enzyme , in vitro
The antioxidant and detoxification activity of almond skin polyphenols (ASP) may contribute to the inverse association observed between nut consumption and the incidence of cardiovascular disease. ASP can interact synergistically with vitamin C (VC) to enhance LDL resistance against oxidation. Thus, we tested the antioxidant capacity of ASP alone and in combination with VC to inhibit by 50% (EC50) DPPH, HOCl, ONOO − , and O 2 −. radicals in vitro. ASP were obtained from methanolic (M) and gastrointestinal mimic (GI) extractions. The EC50 for ASP‐M was 43.2, 21.3, 6.1, and 57.5 and for ASP‐GI was >100, 4.4, 4.2, and >100 μmol/L gallic acid equivalents, respectively. ASP‐GI + VC quenching of DPPH and HOCl was 22.9 and 61.3% more potent ( P ≤ 0.001) than their calculated additive EC50. In contrast, ASP‐M + VC against HOCl and O 2 −. was 45.6 and 25.9% less potent ( P ≤ 0.001) than their calculated additive effect. The capacity of ASP for detoxification was assessed by its effect on quinione reductase (QR) activity in Hepa1c1c7 cells. ASP‐M (100 μmol/L) increased by 21.6% and ASP‐GI (0.1 μmol/L) decreased by 16.2% QR activity. VC did not alter but ASP‐GI + VC synergistically increased QR by 17.4%. These results suggest ASP possess antioxidant activity against free radicals and can enhance phase II enzyme activity. However, these actions are dependent upon the ASP dose, antioxidant combinations, and radical species.