Abstract
γ-Tocopherol, commonly found in seed oils, is the major tocopherol in the U.S. diet, is superior to α-tocopherol in preventing neoplastic transformation, and demonstrates unique reactivity toward NO2. This article describes the products of reaction between γ-tocopherol and low concentrations of gaseous nitrogen dioxide (NO2), as well as their endogenous formation in NO-producing RINm5F cells. γ-Tocopherol in hexane reacts with NO2 to yield two products identified as 2,7,8-trimethyl-2(4,8,12-trimethyltridecyl)-5,6-chromaquinone, "tocored," and 2,7,8 trimethyl-2(4,8,12-trimethyldecyl) 5-nitro, 6-chromanol, "tocoyellow." Physical data for these two compounds and reaction characteristics are described. The formation of tocored is consistent with a proposed mechanism of γ-tocopherol-mediated reduction of NO2 to NO involving initial reaction by NO2 at the C-5 position to form an intermediate nitrite ester tocopheryl radical, which then reacts internally to release NO and form 5,6 epoxy γ-tocopherol. Tautomerization and further oxidation of the latter intermediate by NO2 yields tocored as the main product observed. The reaction of γ-tocopherol with NO2 to form NO occurs independently of light, whereas a-tocopherol requires light to generate NO from NO2. γ-Tocopherol and aminoguanidine, an NO synthase inhibitor, were superior to α-tocopherol in preventing RINm5F cell toxicity induced by Interleukin-1β (IL-1β). Both tocored and tocoyellow were observed to form in RINm5F cells loaded with γ-tocopherol and producing NO constitutively, although a consistent increase in these products as a result of induced NO synthesis was not observed.
| Original language | English |
|---|---|
| Pages (from-to) | 259-269 |
| Number of pages | 11 |
| Journal | Free Radical Biology and Medicine |
| Volume | 19 |
| Issue number | 3 |
| DOIs | |
| State | Published - Jan 1 1995 |
| Externally published | Yes |
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Keywords
- Antioxidants
- Epoxides
- Free radicals
- Nitration
- Nitric oxide
- Nitrogen Oxides
- Tocopherol
ASJC Scopus subject areas
- Biochemistry
- Physiology (medical)
- Clinical Biochemistry
- Medicine(all)
- Toxicology
Cite this
Products of γ-tocopherol reaction with NO2 and their formation in rat insulinoma (RINm5F) cells. / Cooney, Robert V.; Harwood, Patricia J.; Franke, Adrian A.; Narala, Kavitha; Sundström, Anna Karin; Berggren, Per Olof; Mordan, Lawrence J.
In: Free Radical Biology and Medicine, Vol. 19, No. 3, 01.01.1995, p. 259-269.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Products of γ-tocopherol reaction with NO2 and their formation in rat insulinoma (RINm5F) cells
AU - Cooney, Robert V.
AU - Harwood, Patricia J.
AU - Franke, Adrian A.
AU - Narala, Kavitha
AU - Sundström, Anna Karin
AU - Berggren, Per Olof
AU - Mordan, Lawrence J.
PY - 1995/1/1
Y1 - 1995/1/1
N2 - γ-Tocopherol, commonly found in seed oils, is the major tocopherol in the U.S. diet, is superior to α-tocopherol in preventing neoplastic transformation, and demonstrates unique reactivity toward NO2. This article describes the products of reaction between γ-tocopherol and low concentrations of gaseous nitrogen dioxide (NO2), as well as their endogenous formation in NO-producing RINm5F cells. γ-Tocopherol in hexane reacts with NO2 to yield two products identified as 2,7,8-trimethyl-2(4,8,12-trimethyltridecyl)-5,6-chromaquinone, "tocored," and 2,7,8 trimethyl-2(4,8,12-trimethyldecyl) 5-nitro, 6-chromanol, "tocoyellow." Physical data for these two compounds and reaction characteristics are described. The formation of tocored is consistent with a proposed mechanism of γ-tocopherol-mediated reduction of NO2 to NO involving initial reaction by NO2 at the C-5 position to form an intermediate nitrite ester tocopheryl radical, which then reacts internally to release NO and form 5,6 epoxy γ-tocopherol. Tautomerization and further oxidation of the latter intermediate by NO2 yields tocored as the main product observed. The reaction of γ-tocopherol with NO2 to form NO occurs independently of light, whereas a-tocopherol requires light to generate NO from NO2. γ-Tocopherol and aminoguanidine, an NO synthase inhibitor, were superior to α-tocopherol in preventing RINm5F cell toxicity induced by Interleukin-1β (IL-1β). Both tocored and tocoyellow were observed to form in RINm5F cells loaded with γ-tocopherol and producing NO constitutively, although a consistent increase in these products as a result of induced NO synthesis was not observed.
AB - γ-Tocopherol, commonly found in seed oils, is the major tocopherol in the U.S. diet, is superior to α-tocopherol in preventing neoplastic transformation, and demonstrates unique reactivity toward NO2. This article describes the products of reaction between γ-tocopherol and low concentrations of gaseous nitrogen dioxide (NO2), as well as their endogenous formation in NO-producing RINm5F cells. γ-Tocopherol in hexane reacts with NO2 to yield two products identified as 2,7,8-trimethyl-2(4,8,12-trimethyltridecyl)-5,6-chromaquinone, "tocored," and 2,7,8 trimethyl-2(4,8,12-trimethyldecyl) 5-nitro, 6-chromanol, "tocoyellow." Physical data for these two compounds and reaction characteristics are described. The formation of tocored is consistent with a proposed mechanism of γ-tocopherol-mediated reduction of NO2 to NO involving initial reaction by NO2 at the C-5 position to form an intermediate nitrite ester tocopheryl radical, which then reacts internally to release NO and form 5,6 epoxy γ-tocopherol. Tautomerization and further oxidation of the latter intermediate by NO2 yields tocored as the main product observed. The reaction of γ-tocopherol with NO2 to form NO occurs independently of light, whereas a-tocopherol requires light to generate NO from NO2. γ-Tocopherol and aminoguanidine, an NO synthase inhibitor, were superior to α-tocopherol in preventing RINm5F cell toxicity induced by Interleukin-1β (IL-1β). Both tocored and tocoyellow were observed to form in RINm5F cells loaded with γ-tocopherol and producing NO constitutively, although a consistent increase in these products as a result of induced NO synthesis was not observed.
KW - Antioxidants
KW - Epoxides
KW - Free radicals
KW - Nitration
KW - Nitric oxide
KW - Nitrogen Oxides
KW - Tocopherol
UR - http://www.scopus.com/inward/record.url?scp=0029146007&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0029146007&partnerID=8YFLogxK
U2 - 10.1016/0891-5849(95)00019-T
DO - 10.1016/0891-5849(95)00019-T
M3 - Article
C2 - 7557540
AN - SCOPUS:0029146007
VL - 19
SP - 259
EP - 269
JO - Free Radical Biology and Medicine
JF - Free Radical Biology and Medicine
SN - 0891-5849
IS - 3
ER -