Aktuelle Ernährungsmedizin 2007; 32 - P4_11
DOI: 10.1055/s-2007-983431

Formation of 5-nitro-gamma-tocopherol in smokers and non-smokers after mixed tocopherol supplementation

I Sundl 1, A Meinitzer 2, M Maritschnegg 1, JM Roob 3, B Tiran 2, T Verdino 4, O Knes 5, BM Winklhofer-Roob 1
  • 1Human Nutrition & Metabolism Research and Training Center (HNMRC), Institute of Molecular Biosciences, Karl-Franzens University Graz, Graz, Austria
  • 2Clinical Institute of Medical & Chemical Laboratory Diagnostics
  • 3Division of Clinical Nephrology, Department of Internal Medicine, Medical University Graz
  • 4Casa Medica Pharmacy, Graz, Austria
  • 5Institute of Applied Biochemistry, Tägerwilen, Switzerland.

Aims: Smokers are exposed to reactive nitrogen species (RNS) which are present at high amounts in cigarette smoke. Because of an unsubstituted position on the chromanol ring, gamma-tocopherol (GT) but not alpha-tocopherol traps certain RNS with the consequent formation of 5-Nitro-GT (NGT) (1). The aim of this randomized, double-blind placebo-controlled study was to compare NGT concentrations and NGT:GT ratios before and after supplementation with AT and mixed tocopherols (MT) containing 14% AT and 60% GT, and possible determinants of NGT in smokers (S) versus non-smokers (NS).

Methods: Healthy male S (n=34) and NS (n=44), 18–45yrs, were randomly assigned to take either 294mg AT or 36.8, 73.5, 147 or 294mg MT or placebo for 4 wks. Before and after supplementation, plasma AT, GT and ascorbate concentrations were determined by HPLC and NGT by LC-MS. S smoked one cigarette exactly one hour prior to blood drawing.

Results: There were no differences in NGT and the NGT:GT ratio between S and NS. There was a close correlation (r=0.45, P<0.001) between NGT and GT concentrations. Multiple regression analysis including age, cholesterol, ascorbate, AT and GT concentrations as independent variables showed that only GT concentrations predict NGT concentrations (P<0.001). Supplementation with AT decreased NGT (P<0.001) but not NGT:GT. This effect was not observed for MT supplementation. Multiple regression analysis showed that delta NGT (baseline versus 4 wk) is predicted by delta GT (but not by delta AT) in S (P<0.001) and S and NS combined (P<0.001), but not in NS.

Conclusions: One hour after cigarette smoking circulating NGT concentrations do not differ between S and NS. GT concentrations predict NGT concentrations, suggesting that GT is essential to trap RNS in vivo.

References: (1) Leonard SW, Bruno RS, Paterson E, et al., Free Radic Biol Med 2003;35:1560–7.