• Preventive Nutrition and Food Science
• /
• v.9 no.4
• /
• pp.295-299
• /
• 2004

Alpha-tocopherol was thermally oxidized and degraded at high temperatures and the resulting products were chromatographically separated and identified by LC-MS. Alpha-tocopherol dissolved in glycerol was heated at 200^{\circ}C for 30 min. The thermal products were separated by hexane extraction and analyzed by HPLC using a reversed phase $\mu$-Bondapak $C_{18}-column$ with two kinds of elution solvents: a mixture of acetonitrile and methanol (3:2), and of acetonitrile, methanol, 2-propanol, chloroform and methylene chloride (3:2:5:0.5:0.5) in a gradient mode. The isolated thermal. products of alpha-tocopherol were more viscous than alpha-tocopherol, and dark brown in color. Major thermal degradation products of alpha-tocopherol were identified by LC-MS, and the structures of thermal products were proposed. Alpha-tocopherol and its thermal degradation products were degraded into fragments, mainly at the non-aromatic parts. The degradation products of alpha-tocopherol. were combined with oxidized product (tocopherylquinone) to make thermal. products through dimerization.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.19 no.3
• /
• pp.239-247
• /
• 1990

The oxidation products from the mixture of a-tocopherol (a-Toc) and γ-tocopherol)(γ-Toc) during autoxidation of methyl linoleate were isolated and identified. The sturctures of the oxida-tion products were characterized by UV, IR, 1H and 13CNMR and mass spectrometry 5-[2-(a-tocopherol-5'-yl)ethyl]-a-tocopherylquinone 5-[2-(a-tocopherol-5'-yl)ethyl]-8a-hydroxy-a-tocopherone and O-[8-(5-ethoxymethyl-7-methyltocol) methyl] a-tocopherol were obained from the mixture as the oxidation products derived from γ-Toc However oxidation product composed of both a-ToC and γ-Toc was detected in oxidation products of the misture. These results support the facts that at first oxidation of a-Toc proceeds during autoxidation of lipids and then γ-Toc decomposes after approximate consumption of a-Toc.

• Journal of Nutrition and Health
• /
• v.34 no.3
• /
• pp.306-312
• /
• 2001

We investigated the effect of physical exercise on the intakes and plasma levels of vitamin C and E in young male adults. The study population were divided into two groups: small-amount exercisers($\leq$ 30min/day, n=29) and moderate-amount exercisers(> 30min/day, n=32) according to their physical exercise habits measured by a questionnaire. Dietary intakes of vitamin C and E of the subjects were estimated by the 24 hour recall method. Plasma lipid profiles, vitamin C, $\alpha$-tocopherol and ${\gamma}$-tocopherol levels were analyzed. No significant differences were observed in total cholesterol, TG, HDL-C and LDL-C of plasma between two groups. Plasma vitamin C and $\alpha$-tocopherol levels in moderate-amount exercisers were significantly higher than those in small-amount exercisers, although dietary intakes of vitamin C and vitamin E were not significantly different between two groups. However, plasma ${\gamma}$-tocopherol level of moderate-amount exercisers did not significantly differ from small-amount exercisers. There was a positive correlation between the amount of exercise and plasma $\alpha$-tocopherol level. These results suggest that moderate amount of exercise over 30 min per day would lead to a healthy life with an activated antioxidant defence system against oxidative stress.(Korean J Nutrition 34(3) : 306~312, 2001)

• Journal of Nutrition and Health
• /
• v.18 no.1
• /
• pp.29-35
• /
• 1985

This study was designed to evaluate the effects of tocopherol supplementation on serum $HDL_{2}$ and $HDL_{3}$ subfraction and lipoprotein pattern of young rabbits fed the different levels of dietary polyunsaturated fatty acids. White male rabbits with an average bo요 weight of 90kg were assigned into 4 groups : LP( Low PUFA) ; HP( High PUFA) ; LPT( Tocopheror added to LP), HPT(Tocopherol added to HP) by feeding safflower oil or coconut oil at loft( w/w )in addition to thew diet with or without tocopherol for 4 weeks. HDL-Chol and HDL subfractions were determined by polyanionic precipitation method, and the relative amount of lipoprotein by electrophoresis. Serum total cholesterol and TG wer slightly lowered in the group of high PUFA diet and its effect was more in the case of tocopherol supplemented. HDL-Chol level was reduced in the high PUFA diet with or without tocopherol, but overall, HDL-Chol level was not influenced by tocopherol addition and also no significant change in lipoprotein pattern when tocopherol added to the HP diet. $HDL_{2}$ level was increased in HPT group but not in LPT group when tocopherol was added to each HP and LP group, respectively. $HDL_{3}$ levels of both LP and HP groups were reduced with tocopherol supplement, but the reduction was less in the high PUFA groups so that $HDL_{2}$ : $HDL_{3}$ ratio of HP was rather close to that of LP, but it was increased when tocopherol supplemented to the HP diet. Therefore, high PUFA diet could improve the anti atherogenic factor when tocopherol supplemented.

• Journal of Nutrition and Health
• /
• v.23 no.2
• /
• pp.108-114
• /
• 1990

The concentrations of $\alpha$-tocopherol in the brain, liver, and serum were studied with and without saponification process between control and vitamin E supplemented rats. Young rats, 80-120g body weight, were fed control and vitamin E supplemented diets, ad libitum, for four weeks. $\alpha$-Tocopherol concentrations were determined by high pressure liquid chromatography. The $\alpha$-tocopherol concentration per wet weight base in the brain tissue was significantly lower than that in the liver. Vitamin E supplementation had no effect on brain $\alpha$-tocopherol levels in contrast to the significant increase in lover $\alpha$-tocopherol concentration with and without saponification is significantly greater in the brain than in the liver or serum. Further study is needed to clarify the nature of interaction or /and binding between $\alpha$-tocopherol and the complex membrane system in brain tissue. It can be speculated from this and other studies that the metabolism and the nature of interaction of $\alpha$-tocopherol with the complex membrane system in brain tissue rich in polyunsaturated fatty acids seems different from that in liver tissue or serum.

• Journal of Nutrition and Health
• /
• v.43 no.3
• /
• pp.304-314
• /
• 2010

Vitamin E has been a generic term for all tocopherol and tocotrienol derivatives. The most active form of vitamin E isoforms in vivo is regarded to be $\alpha$-tocopherol which is the only form defined as vitamin E in the US Food and Nutrition Board, causing controversy over setting dietary reference intake (DRI) of vitamin E. However, most of the countries other than the US maintain the original concept that all isoforms are accepted as vitamin E but with different biopotency. The roles of the isoforms of vitamin E other than $\alpha$-tocopherol have received continuous attention. Among them those of $\gamma$-tocopherol and $\alpha$-tocotrienol have been most studied in comparison with $\alpha$-tocopherol, since $\gamma$-tocopherol comprises major form of vitamin E in many plant seeds and those of the both vitamin E have been implicated in unique physiological functions. This review summarizes findings that have led a better understanding of vitamin E absorption, transport, tissue storage and various functions common and specific to vitamin E isoforms focusing $\alpha$- and $\gamma$-tocopherol as well as tocotrienols. It is expected to help redefining vitamin E and setting its DRI for Koreans.

• Molecules and Cells
• /
• v.24 no.2
• /
• pp.301-306
• /
• 2007

Tocopherols, essential components of the human diet, are synthesized exclusively by photosynthetic organisms. To increase tocopherol content by increasing total flux to the tocopherol biosynthetic pathway, genes encoding Arabidopsis homogentisate phytyltransferase (HPT/V-TE2) and tocopherol cyclase (TC/VTE1) were constitutively overexpressed in lettuce (Lactuca sativa L.). Total tocopherol content of the transgenic plants overexpressing either of the genes was increased by more than 2-fold mainly due to an increase in ${\gamma}$-tocopherol. However, chlorophyll content in the HPT/VTE2 and TC/VTE1 transgenic lines decreased by up to 20% and increased by up to 35%, respectively (P < 0.01). These results demonstrate that manipulation of the tocopherol biosynthetic pathway can increase or decrease chlorophyll content depending on the gene introduced.

• Nutrition Research and Practice
• /
• v.9 no.2
• /
• pp.192-198
• /
• 2015

BACKGROUND/OBJECTIVES: Vitamin E is a fat-soluble vitamin and functions primarily as a lipid antioxidant. Inadequate vitamin E status may increase risk of several chronic diseases. Thus, the objectives of this study were to estimate intake and plasma concentration of each tocopherol and to evaluate vitamin E status of Korean adults. SUBJECTS/METHODS: Three consecutive 24-h food recalls and fasting blood samples were collected from healthy 20- to 59-y-old adults (33 males and 73 females) living in the Seoul metropolitan area, South Korea. ${\alpha}$-, ${\beta}$-, ${\delta}$-, and ${\gamma}$-tocopherol intakes and plasma concentrations of tocopherols (${\alpha}$-, ${\delta}$-, and ${\gamma}$- tocopherol) were analyzed by gender. RESULTS: Dietary vitamin E and total vitamin E intake (dietary plus supplemental vitamin E) was $17.68{\pm}14.34$ and $19.55{\pm}15.78mg$ ${\alpha}$-tocopherol equivalents, respectively. The mean daily ${\alpha}$-tocopherol, and ${\gamma}$-tocopherol intakes were $3.07{\pm}2.27mg$ and $5.98{\pm}3.74mg$, respectively. Intakes of total vitamin E and each tocopherol of males were significantly higher than those of females (P < 0.05). Plasma ${\alpha}$-tocopherol concentration was $15.45{\pm}10.16$ of males and $15.00{\pm}4.54{\mu}mol/L$ of females, respectively. There were no significant differences in plasma tocopherol concentrations by gender ($P{\geq}0.05$). Plasma ${\alpha}$-tocopherol was negatively correlated with ${\gamma}$-tocopherol intake (P < 0.05). Twenty-three percent of the subjects had plasma ${\alpha}$-tocopherol concentrations < $12{\mu}mol/L$ indicating a biochemical deficiency of vitamin E. Approximately 8% and 9% of these participants had plasma ${\alpha}$-tocopherol:total lipid ratio less than $1.59{\mu}mol/mmol$ and plasma ${\alpha}$-tocopherol:total cholesterol ratio less than $2.22{\mu}mol/mmol$, respectively, which are also indicative of vitamin E deficiency. CONCLUSIONS: Vitamin E intakes of Korean adults were generally adequate with the Korean Dietary Reference Intakes for vitamin E. However, ${\alpha}$-tocopherol intake was lower than that reported in other countries, and 23% of the subjects in the current study were vitamin E deficient based on plasma ${\alpha}$-tocopherol concentrations.

• Journal of Nutrition and Health
• /
• v.21 no.5
• /
• pp.295-304
• /
• 1988

To study effect of dietary polyunsaturated fatty acid and $\omega$-tocopherol content on lipid peroxidation in rat liver, rats were fed for 3, 6 and 9 weeks with normal tocopherol diet added 40mg of DL-$\alpha$-tocopherol/kg of diet (PF group), high tocopherol eit 200mg of DL-$\alpha$-tocopherol/kg of diet(PFE group), low tocopherol diet without addition of DL-$\alpha$-tocopherol to diet(PFO group), and control diet added 40mg of DL-$\alpha$-tocopherol/kg of diet(control group). Each diet group supplied 45% of total calorie from corn oil except control group which supplied 12% of total calorie from corn oil. After each feeding period, lipid peroxide and tocopherol contents were measured in the liver as well as activities of glutathione peroxidase and superoxide dismutase. PF group had almost the same contents of liver peroxide, tocopherol contents and activities of glutathione peroxidease and superoxide dimutase as control group, while PFE group had higher tocopherol content and glutathione peroxidase activity and lower lipid peroxide contents and superoxide dismutase activity than control group. On the other hand, changes in the values of PFO group were opposite to those of PFE group. Differences in the values among groups were more pronounced as feeding period became longer.

• Applied Biological Chemistry
• /
• v.25 no.4
• /
• pp.224-231
• /
• 1982

${\alpha}-Tocopherol$ was found to be a fluorescent probe in determination of the phasetransition temperature of liposome. Since this was a discovery of a new aspect of ${\alpha}-tocopherol$ as an important biochemical molecule, its molecular spectroscopic characterization was carried out in order to obtain some informations on its spectral and, structural properties in various media, anticipating that the compound may entertain a wide applications in biochemical systems as a spectroscopic probe. Two species of α${\alpha}-tocopherol$, monomer and dimer, were found to exist in organic media, especially in solvents of nonhydrogen bonding ability. Monomer with maximum UV-absorption around $(291{\sim}294nm)$ is highly fluorescent, while dimer which is formed by intermolecular hydrogen bonds and absorbes with spectral peak at 298nm is nonfluorescent. ${\alpha}-tocopherol$ incorporated to liposome exhibits emission property quite different from that in various organic media showing broad and red-shifted fluorescence excitation and emission spectra. This spectral abnormality is to be interpreted to arise from chromanolate-type ion, H-dissociated ${\alpha}-tocopherol$.