title: α-Tocopherol supplementation reduces 5-nitro-γ-tocopherol accumulation by decreasing γ-tocopherol in young adult smokers.
abstract: γ-Tocopherol (γ-T) scavenges reactive nitrogen species (RNS) to form 5-NO2-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, n = 11) and non-smokers (21 ± 2 y, n = 10) ingested 75 mg/d each of RRR- and all-rac-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 (P = 0.07) to increase post-supplementation only in smokers, supporting decreases in RNS scavenging by γ-T. Plasma NGT concentration was more strongly correlated (P < 0.05) with γ-T in smokers (R = 0.83) compared with non-smokers (R = 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.
authors.affiliation: Department of Nutritional Sciences University of Connecticut, Storrs, CT 06269.
authors.forename: Ruisong
authors.initials: R
authors.lastname: Pei
authors.affiliation: Human Nutrition Program, Department of Human Sciences, The Ohio State University, Columbus, OH 43210.
authors.forename: Eunice
authors.initials: E
authors.lastname: Mah
authors.affiliation: Linus Pauling Institute, Oregon State University, Corvallis, OR 97331.
authors.forename: Scott W
authors.initials: SW
authors.lastname: Leonard
authors.affiliation: Linus Pauling Institute, Oregon State University, Corvallis, OR 97331.
authors.forename: Maret G
authors.initials: MG
authors.lastname: Traber
authors.affiliation: Human Nutrition Program, Department of Human Sciences, The Ohio State University, Columbus, OH 43210.
authors.forename: Richard S
authors.initials: RS
authors.lastname: Bruno
mesh_terms: D000293:Adolescent; D000328:Adult; D002839:Chromans / Q000737:chemistry; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D008297:Male; D009566:Nitrates / Q000737:chemistry; D009573:Nitrites / Q000737:chemistry; D018384:Oxidative Stress; D026361:Reactive Nitrogen Species / Q000737:chemistry; D012907:Smoking / Q000009:adverse effects*; D014810:Vitamin E / Q000378:metabolism; D055815:Young Adult; D024502:alpha-Tocopherol / Q000494:pharmacology*; D024504:gamma-Tocopherol / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: C406664:5-nitro-gamma-tocopherol; D002839:Chromans; D009566:Nitrates; D009573:Nitrites; D026361:Reactive Nitrogen Species; C483420:carboxyethyl-hydroxychroman; D014810:Vitamin E; D024504:gamma-Tocopherol; D024502:alpha-Tocopherol
keywords: nitro-γ-tocopherol; reactive nitrogen species; vitamin E