• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.6
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• pp.1047-1052
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• 1998

The effects of antioxidants such as ascorbyl palmitate(AP), tocopherol( Toc), BHA and ascorbyl palmitate＋ tocopherol(AP＋ Toc) on lipid peroxide formations in lard have been investigated during storage at 50oC after gamma irradiation with the dose of 1~10kGy. Immediately gamma irradiation greatly increased the initiative oxidation of lard as expected. But antioxidants were found to be greatly effective in minimizing the radiation induced peroxidation of lard. The decreasing order of effects on their antioxidative activities was AP>AP＋ Toc>BHA> Toc. Oxidation of lard during storage at 50oC after irradiation induced the acceleration of autooxidation. But the additions of an tioxidants inhibited the formation of peroxides. Their antioxidative activities during storage were BHA> AP＋ Toc> Toc>AP. Especially AP＋ Toc mixture was not significantly different from BHA (p>0.05).

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

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2003.10a
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• pp.182-182
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• 2003

• Korean Journal of Food Science and Technology
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• v.50 no.3
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• pp.267-273
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• 2018

Horse fat was extracted from fatty horse meat at $70^{\circ}C$ under vacuum conditions. The oxidative stability of horse fat was investigated by the addition of 0, 30, 60, and 150 mg/kg of ${\alpha}$-, ${\gamma}$-, or ${\delta}$-tocopherol during storage of 14 days at $65^{\circ}C$ in the dark. Changes of tocopherol concentration and fatty acid composition, peroxide value, and 2-thiobarbituric acid (TBA) value were analyzed during storage. The levels of the added tocopherols were found to decrease during storage. Unsaturated fatty acids contents of horse fat without tocopherol decreased from 60.87% to 57.22% after 14 days. The peroxide value and TBA value increased as storage time increased. The peroxide values of horse fat after addition of 0, 30, 60, and 150 mg/kg of ${\gamma}$-tocopherol were 43.75, 25.17, 20.87, and 15.41 meq/kg, respectively, and the TBA values were 7.87, 5.64, 4.43, and 4.23 mg malonaldehyde (MA)/kg, respectively, after 14 days. At the concentration of 150 mg/kg, both ${\gamma}$- and ${\delta}$-tocopherol impeded the oxidation of horse fat during storage.

• Journal of Nutrition and Health
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• v.34 no.4
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• pp.401-408
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• 2001

The spontaneous frequency of genetic damage and the possible relationship of this damage to total radical-trapping antioxidant potential(TRAP) and antioxidant vitamins, including plasma levels of $\alpha$-carotene, $\beta$-carotene, cryptoxanthin, retinol, $\alpha$-tocopherol and ${\gamma}$-tocopherol in humans were investigated in 57 subjects using two indices of genetic damage, SCE & HFC frequency. The mean of SCE and HFC frequencies were weakly correlated with plasma TRAP(r=-0.305, p<0.1 for SCEs: r=-0.297, p<0.1 for HFCs, respectively), but those were strongly negatively correlated with plasma $\beta$-carotence(r=-0.385, p<0.01 for SCEs : r=-0.392, p<0.01 for HFCs) and cryptoxanthin(r=-0.312, p<0.05 for SCEs : r=0.335, p<0.05 for HFCs, respectively) levels in the subjects. However, those DNA damage markers including SCE and HFC did not correlate with either plasma $\alpha$-carotene, $\alpha$-tocopherol or retinol concentrations. The mean of SCE and HFC frequencies were positively correlated with plasma ${\gamma}$-tocopherol level(r=0.421, p<0.01 for SCEs : r=0.399, p<0.01 for HFCs, respectively). These findings indicate that increased cytogenetic DNA changes, as determined by SCE and HFC frequencies are possibly associated with generation of free radicals in lymphocytes and decreased plasma antioxidant vitamin($\beta$-carotene and cryptoxanthin) status in the subjects. (Korean J Nutrition 34(4) : 401~08, 2001)

• Journal of the Korean Society of Food Science and Nutrition
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• v.13 no.4
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• pp.427-431
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• 1984

This experiment was conducted to study the effects of Korean ginseng and tocopherol on serum testosterone level, protein metabolism and swimming endurance in rats. Powdered ginseng (2.5 g/kg) and ${\alpha}-tocopherol$ (250 mg/kg) were added directly into the basal diet of rats feeding for 6 weeks. The serum testosterone level of ginseng-treated rats had no difference from that of control rats, but the level was slightly increased in tocopherol-treated rats. In the case of ginseng-treated rats, there were no significant difference in the contents of albumin, ${\alpha}_1-globulin$, ${\alpha}_2-globulin$, ${\gamma}-globulin$ and A/G ratio compared with those of the control rats, however, the levels of total protein and ${\beta}-globulin$ were increased significantly(p<0.005). Total protein value of tocopherol-treated rats was higher than that of the control rats(p<0.005). In contrast, albumin content was slightly decreased. The contents of ${\alpha}_1-globulin$, ${\alpha}_2-globulin$, ${\beta}-globuiln$ and ${\gamma}-globulin$ were higher in the rats fed tocopherol diet that those obtained from the control rats. Accordingly A/G value was markedly decreased (p<0.001). In swimming endurance test, both Korean ginseng and ${\alpha}-tocopherol$ did not appear to have any effect on rats' stamina.

• Preventive Nutrition and Food Science
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• v.3 no.1
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• pp.48-55
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• 1998

An acute ethanol load(50mmol/kg , i.p) resulted in an increase in peroxidation and a decrease in the levels of $\alpha$-tocopherol and ascorbate in rat cerebellum. Pretreatement with allopurinol(146$\mu$mol/kg, i.p) prevented the ethnol-induced increment in lipid peroxidation and decrease in $\alpha$-tocopherol content. However, the decrease of ascorbate was of greater magnitude when allopurinol was associated with ethanol. These results suggested that allopurinol. besides its action as a radical scavenger and xanthine oxidase inhibitor, might favor the regeneration of $\alpha$-tocopherol antioxidant acitviity was studied using ${\gamma}$-radiolysis in aerated ethanolic solutions. Even though allopurinol did not react by itself with $\alpha$-hydroxyethyl-peroxyl radicals [H3C-CH(OH)OO] , it enhance the $\alpha$-hydroxyethyl-peroxyl radical scavenging properties of $\alpha$tocopherol. The regeneration of $\alpha$-tocopherol from the $\alpha$-hydroxyethyl-peroxyl radical scavenging properties of $\alpha$-tocophero. The regeneration of $\alpha$-tocopherol from the $\alpha$-tocopherol radical by ascorbate remained as efficient in the presence of allopurinol as in its absence. The effects of allopurinol on the Vitamin E oxidation-reduction mechanism could be involoved in the beneficial effectof allopurinol on the biological cellular damages linked to free radical reactions.

• Journal of the East Asian Society of Dietary Life
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• v.4 no.2
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• pp.51-57
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• 1994

Six sesame oils prepared from Korean and Chinese sesame were oxidized at 40$^{\circ}C$ for 16 weeks in a dark place. Effects of oxidative stability on tocopherols of those sesame oils were studied in related to chemical changes in the oils. All oil samples showed that the rate of tocopherol reduction was increased by the storage time. The changes of peroxide value, free fatty acid, carbonyl content were not caused in direct relation to the tocopherols oxidation. The amount of total tocopherol in the Korean sesame oil ranged from 48.7-50.3mg/100g and Chinese seseame oil ranged from 42.4-44.7 mg/100g According to the three individual tocopherols remaining content after 16weeks, ${\gamma}$-,${\alpha}$-,${\beta}$- tocopherol showed 70%, 30%, 20% of initial concentrations in the oils respectively. There was no significant difference between Korean and Chinese sesame oil except the higher total amount of the tocopherol in Korean sesame oil than that of Chinese.

• Nutrition Research and Practice
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• v.3 no.3
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• pp.185-191
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• 2009

The elevated level of circulating estradiol increases the risk of breast tumor development. To gain further insight into mechanisms involved in their actions, we investigated the molecular mechanisms of 4-hydroxyestradiol (4-$OHE_2$) to initiate and/or promote abnormal cell growth, and of $\alpha$- or $\gamma$-tocopherol to inhibit this process. MCF-10A, human breast epithelial cells were incubated with $0.1{\mu}M$ 4-$OHE_2$, either with or without $30{\mu}M$ tocopherols for 96 h. 4-$OHE_2$ caused the accumulation of intracellular ROS, while cellular GSH/GSSG ratio and MnSOD protein levels were decreased, indicating that there was an oxidative burden. 4-$OHE_2$ treatment also changed the levels of DNA repair proteins, BRCA1 and PARP-1. $\gamma$-Tocopherol suppressed the 4-$OHE_2$-induced increases in ROS, GSH/GSSG ratio, and MnSOD protein expression, while $\alpha$-tocopherol up-regulated BRCA1 and PARP-1 protein expression. In conclusion, 4-$OHE_2$ increases oxidative stress reducing the level of proteins related to DNA repair. Tocopherols suppressed oxidative stress by scavenging ROS or up-regulating DNA repair elements.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.31-31
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• 2017

Understanding the mechanism(s) to overcome or prevent seed ageing deterioration during storage is of fundamental interest to seed physiologists. Vitamin E (tocols) is known as a key metabolite to efficiently scavenge lipid peroxy radicals which cause membrane breakdown resulting in seed ageing. However, in rice research this hypothesis has been tested for very few lines only without considering intraspecific variation in genomic structure. Here, we present a correlation study between tocols and seed longevity using a diverse rice panel. Seeds of 20 rice accessions held in the International Rice Genebank at the International Rice Research Institute, representing aus, indica, temperate japonica and tropical japonica subpopulations, were used for tocols analysis (quantification of ${\alpha}$-, ${\beta}$-, ${\gamma}$-, ${\delta}$-tocopherol/tocotrienol by ultra performance liquid chromatography) and storage experiments at $45^{\circ}C$ and 10.9% seed moisture content (sample taken for germination testing every 3 days up to 60 days). To examine interactions between DNA sequences and phenotype, the 700k high-density single-nucleotide polymorphism marker data-set was utilized. Both seed longevity (time for viability to fall to 50%; $p_{50}$) and tocols content varied across subpopulations due to heterogeneity in the genetic architecture. Among eight types of tocol homologues, ${\alpha}$-tocopherol and ${\gamma}$-tocotrienol were significantly correlated with $p_{50}$ (negatively and positively, respectively). While temperate japonica varieties were most abundant in ${\alpha}$-tocopherol, indica varieties recorded 1.3 to 1.7-fold higher ${\gamma}$-tocotrienol than those of other subpopulations. It was highlighted that specific ratio of tocol homologues rather than total tocols content plays an important role in the seed longevity mechanism.