Dietary Effect of .ALPHA.-Tocopherol and Tocotrienols on Lipid Metabolism and Immune Function of Aged Sprague-Dawley Rats.

Abstract

Eight-month-old male Sprague Dawley rats were fed diets containing ␣-tocopherol (Toc) or tocotrienol (T3) mixture (composed of 20.5% ␣-Toc, 21.4% ␣-T3, 36.5% ␥-T3 and other analogs) at the 0.1 or 0.5% level for 3 weeks to examine their dietary effects on lipid metabolism and immune indices. Feeding of ␣-Toc and T3 significantly decreased liver phosphatidylcholine peroxide and serum phospholipid levels. In the regulation of immunoglobulin level, significant increase in serum IgA level was observed in the rats fed ␣-Toc or T3, but the effect on immunoglobulin productivity from spleen and mesenteric lymph node (MLN) was not as marked. Feeding of ␣-Toc and T3 significantly decreased LTB 4 -releasing activity of peritoneal exudate cells without decreasing arachidonic acid level. The suppression of LTB 4 release was more marked in the rats fed 0.1% ␣-Toc or T3 than in these fed them at the 0.5% level. When animals were killed after 10 h of fasting, T3 was detected only in MLN and epidydimal adipose tissue. These results suggest that T3 modulates lipid metabolism and immune functions as well as ␣-Toc, and that MLN and adipose tissue are the main target tissues of T3.

Specific accumulation of γ- and δ-tocotrienols in tumor and their antitumor effect in vivo

“…Of note, the increase in α-Toc level in the lungs was observed in the γ-T3 feeding group. On the other hand, the α-Toc level in the lungs of Sprague-Dawley rats fasted for 10 h was decreased by T3 mixture (36.5% γ-T3, 21.4% α-T3 and 8.6% δ-T3) feeding [3]. Taken together, it is suggested that the composition of T3 diets plays an important role in α-Toc accumulation in tissues.…”

“…Although both Toc and T3 have various effects such as antioxidative activities [1], T3 have been reported to have additional properties such as hypocholesterolemic and immunoregulatory activities [2][3][4][5]. Among T3 homologues, α-T3 has been reported to have a potent neuroprotective effect [6,7].…”

Apoptosis induction by γ-tocotrienol in human hepatoma Hep3B cells

“…In this study, Hep3B cells were treated with 25, 50 or 75 AM of T3. Previously, we showed that high level of T3s exists in the liver of rats on the marrow of T3 feeding [2,30]. We used T3 concentrations according to this information.…”

“…In addition, T3 homologues differ from each other by the number of methyl groups in the chroman ring. T3 has been reported to have various activities, such as antioxidative, hypocholesterolemic and immunoregulatory activities [1,2]. It has also been reported to inhibit the proliferation of rat hepatoma dRLh-84 cells, normal mouse mammary epithelial cells, human breast carcinoma MCF-7, human leukemia HL-60 and murine B16 melanoma cells in vitro [3 -6], and skin cancer cells in vivo [6].…”