Evaluation of antioxidant activity of vanillin by using multiple antioxidant assays

Background: Vanillin, a compound widely used in foods, beverages, cosmetics and drugs, has been reported to exhibit multifunctional effects such as antimutagenic, antiangiogenetic, anti-colitis, anti-sickling, and antianalgesic effects. However, results of studies on the antioxidant activity of vanillin are not consistent. Methods: We systematically evaluated the antioxidant activity of vanillin using multiple assay systems. DPPH radical-, galvinoxyl radical-, and ABTS center dot(+)-scavenging assays, ORAC assay and an oxidative hemolysis inhibition assay (OxHLIA) were used for determining the antioxidant activity. Results and conclusion: Vanillin showed stronger activity than did ascorbic acid and Trolox in the ABTS center dot(+)-scavenging assay but showed no activity in the DPPH radical- and galvinoxyl radical-scavenging assays. Vanillin showed much stronger antioxidant activity than did ascorbic acid and Trolox in the ORAc assay and OxHLIA. In the ABTS center dot(+)-scavenging assay, ORAC assay and OxHLIA, vanillin reacted with radicals via a self-dimerization mechanism. The dimerization contributed to the high reaction stoichiometry against ABTS center dot(+) and AAPH-derived radicals to result in the strong effect of vanillin. Oral administration of vanillin to mice increased the vanillin concentration and the antioxidant activity in plasma. These data suggested that antioxidant activity of vanillin might be more beneficial than has been thought for daily health care. General significance: Based on the results of the present study, we propose the addition of antioxidant capacity to the multifunctionality of vanillin. (C) 2010 Elsevier B.V. All rights reserved.