Sait Çelik

Effects of Certain Micronutrients and Melatonin on Plasma Lipid, Lipid Peroxidation, and Homocysteine Levels in Rats

BACKGROUND Numerous studies suggest an association between high intake of antioxidant vitamins and fish oil and reduced risk of coronary heart disease. Hyperhomocysteinemia has also been identified as an independent risk factor for arteriosclerosis. In this paper, we aimed to evaluate the effects of vitamin E, vitamin C, vitamin C 6 palmitate (VC6P), lipoic acid, fish oil, and melatonin supplementation on lipid peroxidation, plasma lipid, and homocysteine (Hcy) levels in rats. METHODS Animals were divided into seven groups: one was used as control and each remaining group was supplemented with one substance for 6 weeks. All substances were dissolved in olive oil and injected intraperitoneally (i.p.) with the exception of vitamin C, which was dissolved in drinking water. Plasma Hcy, lipid peroxidation, and lipids were determined. RESULTS Plasma malondialdehyde (MDA) levels decreased significantly in melatonin (p <0.01), lipoic acid (p <0.01), and vitamin E (p <0.05) groups. On the other hand, supplementation with vitamin C and VC6OP lowered MDA levels moderately but not significantly (p >0.05). Fish oil supplementation caused a slight but insignificant increase in plasma MDA levels (p >0.05). Plasma lipid levels in animals treated with melatonin, vitamin E, vitamin C, lipoic acid, and fish oil were significantly lower than those of controls; however, treatment of rats with VC6P has no significant effect on plasma lipid level. Melatonin and fish oil administration significantly lowered plasma Hcy levels, whereas VC6P elevated its level. There was no significant effect of vitamin E, vitamin C, and lipoic acid on levels of plasma Hcy. CONCLUSIONS Our data suggest that supplementation with antioxidants appears to be hypolipidemic. In addition to these beneficial effects, administration of melatonin and fish oil deserves careful consideration as a measure to lower plasma Hcy levels and reduce risk of cardiovascular diseases.

The Effects of Dietary Selenium and Vitamin E and their Combination on the Fatty Acids of Erythrocytes, Bone Marrow and Spleen Tissue Lipids of Lambs

The object was to determine the influence of dietary vitamin E, selenium and their combination on the fatty acid con‐tent of erythrocytes, bone marrow and spleen lipids of Akkaraman lambs. After supplementation for 15 days, the amount of all fatty acids was slightly higher (p < 0·05) in the vitamin E as compared to the control group, whereas the amount of longer fatty acids was significantly higher (p < 0·01, p < 0·001) in the selenium and combination groups. On the thirtieth day, the amount of all fatty acids was slightly high (p < 0·5) in all the supplemented groups in comparison with the control group. In the bone marrow lipids, the amount of longer fatty acids was decreased (p < 0·05, p < 0·01, p < 0·001) in the vitamin E and combination groups as compared to the control. Although the amount of some fatty acids was high (p < 0·05, p < 0·01) in the selenium group compared to the control, linoleic (18:2), linolenic (18:3) and the polyunsaturated fatty acids (PUFA) were lower (p < 0·05, p < 0·001). In the spleen lipids, the amount of longer fatty acids was slightly decreased (p < 0·05) in the vitamin E group as compared with the control; however the amount of longer fatty acids was significantly higher (p < 0·05, p < 0·01) in the selenium and combination groups in comparison to the control group. Thus dietary supplementation with selenium was more effective than dietary vitamin E supplementation in altering the fatty acid content of the erythrocyte, bone marrow and spleen lipids.

Protective role of intraperitoneally administrated vitamin E and selenium on the levels of total lipid, total cholesterol, and fatty acid composition of muscle and liver tissues in rats.

The aim of this work was to determine the protective effects of intraperitoneally administrated vitamin E and Se on total lipid, total cholesterol, and fatty acid composition of rat liver and muscle tissues. Total lipid content of muscle tissue in Se and combination groups decreased as compared to the control group. However, the level of total lipid in the liver tissues was seen to decrease only in the combination group (P < 0.05). While the amount of total cholesterol in liver tissue was lower (P < 0.05) in the vitamin E and combination groups, the amount of total cholesterol in muscle tissue decreased (P < 0.05) in the combination group.

Influence of dietary selenium and vitamin E on the levels of fatty acids in brain and liver tissues of lambs

In this study, the effects of dietary vitamin E, selenium, and their combination on the levels of fatty acid composition of the brain and liver tissues were examined. In brain tissue, the amounts of most fatty acids increased in vitamin E, combination and selenium groups compared with control group values. While the proportions of myristic, pentadecanoic, palmitic, linoleic, and total saturated fatty acids were decreased in vitamin E, Se and combination groups, eicosapentaenoic, total unsaturated and MUFA were increased in the same groups. In addition, the proportions arachidonic, eicosapentaenoic, total unsaturated, ω6 and MUFA in the combination group were higher than in the control group. In liver tissue, the amounts of myristic, pentadecanoic, palmitic, eicosedienoic, eicosapentaenoic, docosahexaenoic, ω3 and PUFA were higher in the combination group than in the control group. Also the proportions of eicosapentaenoic, docosahexaenoic acids in supplemented groups were higher than those in the control group. We conclude that dietary vitamin E and selenium have an influence on the levels of fatty acids in the brain and liver. Copyright

The effects of selenium, vitamin E and their combination on the composition of fatty acids and proteins in Saccharomyces cerevisiae

The aim of our studies was to test the effect and role of vitamin E and selenium supplements on yeast cell. In this study, the effects of selenium (Se), vitamin E (Vit. E), and their combination (Se plus Vit. E) on the composition of fatty acids and proteins were examined in Saccharomyces cerevisiae strains WET136 and 522. S. cerevisiae cells were grown up in YEPD medium supplemented with Se, Vit. E or their combination. It was found that the level of stearic acid was increased in all supplemented groups (p<0·05; p<0·001). The content of saturated and unsaturated fatty acids was decreased (p<0·05; p<0·01; p<0·001) in Vit. E and Vit. E plus Se supplemented S. cerevisiae. On the other hand, Se alone caused an increase (p<0·001) in the saturated fatty acids but a decrease (p<0·05; p<0·001) in the unsaturated fatty acids. Total proteins in S. cerevisiae were significantly increased (p<0·001) by Vit. E supplement. There was no significant change observed in S. cerevisiae supplemented with Se. These findings indicate that membrane composition of S. cerevisiae is affected by both Vit. E and Se supplements.

Influences of Intraperitoneally and Dietary Administered Vitamin E and Selenium on the Lipid Composition in Reproductive Organs of Male Animals

The aim of this work was to determine the protective effect of intraperitoneally and dietary administered vitamin E and selenium (Se) on the total lipid, cholesterol, and fatty acid composition in rat and lamb testes. The level of total lipid in rat testes was significantly decreased (p < 0.001) in the combination group as compared to the control group but slightly decreased in lamb testes (p < 0.05). In addition, the level of total lipid in lamb testes was significantly decreased (p < 0.001) by the Se alone. The content of total cholesterol in rats was higher in the Se group and its level in lamb testes was higher in the vitamin E groups than in the control group (p < 0.001). In rats testes, the amounts of palmitic, oleic, arachidonic acids, the total fatty acid, total unsaturated and total omega 6 acids were higher (p < 0.001) in the Se group. The proportions of palmitic and arachidonic acids were reduced in the vitamin E group and linoleic acid, total unsaturated, and total omega 6 fatty acids were high (p < 0.05) in the vitamin E and combination groups. In lamb testis tissues, the amounts of palmitic, arachidonic, total unsaturated and total omega 6 fatty acids were decreased in the vitamin E group in comparison to the control (p < 0.05). However, the amounts of arachidonic and total omega 6 fatty acids increased (p < 0.05) in the Se group. The proportions of arachidonic acid, total unsaturated fatty acid and total omega 6 fatty acids were high (p < 0.05) in the Se and combination groups. We concluded that the level of total lipid in testis tissues was reduced by dietary and intraperitoneally administered vitamin E and Se together. In contrast, it seems that the proportions of unsaturated and essential fatty acids in examined tissues are increased by vitamin E and Se.