Α-Tocopherol supplementation reduces 5-nitro-γ-tocopherol accumulation by decreasing γ-tocopherol in young adult smokers*. (September 2015)

• Record Type: Journal Article
• Authors: Pei, R.; Mah, E.; Leonard, S. W.; Traber, M. G.; Bruno, R. S.
• Is Part Of: Free radical research. Volume 49:Number 9(2015:Sep.)
• Page Start: 1114
• Page End: 1121
• Publication Date: 2015-09
• Subjects: Free radicals (Chemistry) -- Periodicals; Antioxidants -- Periodicals; Vitamin C -- Periodicals; Vitamin E -- Periodicals; 541.224
• DOI: 10.3109/10715762.2015.1040788
• Languages: English
• ISSNs: 1071-5762

Abstract

<abstract> <title>Abstract</title> <p>γ-Tocopherol (γ-T) scavenges reactive nitrogen species (RNS) to form 5-NO<sub>2</sub>-γ-T (NGT). However, α-T supplementation decreases circulating γ-T, which could limit its RNS scavenging activities. We hypothesized that α-T supplementation would mitigate NGT accumulation by impairing γ-T status. Healthy smokers (21 ± 1 y, <italic>n</italic> = 11) and non-smokers (21 ± 2 y, <italic>n</italic> = 10) ingested 75 mg/d each of <italic>RRR</italic>- and <italic>all-rac</italic>-α-tocopheryl acetate for 6 d. Plasma α-T, γ-T, γ-carboxyethyl hydroxychromanol (CEHC), NGT, and nitrate/nitrite were measured prior to supplementation (Pre), the morning after 6 consecutive evenings of supplementation (Post 1), and on the mornings of d 6 (Post 6) and d 14 (Post 14) during the post-supplementation period. α-T supplementation increased plasma α-T, and decreased γ-T, in both groups and these returned to Pre concentrations on Post 6 regardless of smoking status. Plasma γ-CEHC increased after the first dose of supplementation in both groups, suggesting that α-T supplementation decreased plasma γ-T in part by increasing its metabolism. Plasma NGT and nitrate/nitrite concentrations at Pre were greater in smokers, indicating greater nitrative stress due to cigarette smoking. Plasma NGT concentration was lowered only in smokers on Post 1 and Post 6 and was restored to Pre levels on Post 14. Plasma nitrate/nitrite tended (<italic>P</italic> = 0.07) to increase post-supplementation only in smokers, supporting decreases in RNS scavenging by γ-T. Plasma NGT concentration was more strongly correlated (<italic>P</italic> < 0.05) with γ-T in smokers (<italic>R = </italic>0.83) compared with non-smokers (<italic>R = </italic>0.50), supporting that α-T-mediated decreases in γ-T reduces NGT formation. These data indicate that α-T supplementation limits γ-T scavenging of RNS in smokers by decreasing γ-T availability.</p> </abstract>