Dietary sesame seed and its lignans inhibit 2,7,8-trimethyl- 2(2'-carboxyethyl)-6-hydroxychroman excretion into urine of rats fed gamma-tocopherol.
We showed previously that dietary sesame seed and its lignans elevate the tocopherol concentration in rats. To clarify their effect on tocopherol metabolism, we determined in this study the urinary excretion of 2,7,8-trimethyl-2(2'-carboxyethyl)-6-hydroxychroman (gamma-CEHC), a gamma-tocopherol metabolite, in rats fed sesame seed or its lignans. Rats were fed diets with or without sesame seed for 28 d in Experiment 1, and for 1, 3 and 7 d in Experiment 2. On d 28, dietary sesame seed elevated (P < 0.05) gamma-tocopherol concentrations in liver, kidney, brain and serum, and decreased (P < 0.05) urinary excretion of gamma-CEHC. The excretion was completely inhibited by feeding sesame seed on d 1 and 3. In Experiment 3, the effects of dietary sesamin and sesaminol (major lignans in sesame seed) or ketoconazole (a selective inhibitor of cytochrome P(450) (CYP)3A on urinary excretion of gamma-CEHC in rats fed gamma-tocopherol were examined. The urinary gamma-CEHC in rats fed sesamin or sesaminol was markedly lower than in rats fed gamma-tocopherol alone (P < 0.05). Dietary ketoconazole also inhibited (P < 0.05) urinary excretion of gamma-CEHC, and elevated (P < 0.05) gamma-tocopherol concentrations in tissues and serum of rats fed gamma-tocopherol. These data suggest that sesame seed and its lignans elevate gamma-tocopherol concentration due to the inhibition of CYP3A-dependent metabolism of gamma-tocopherol.
Ikeda
Saiko
S
Department of Food and Nutrition, School of Life Studies, Sugiyama Jogakuen University, Nagoya 464-8662, Japan.
Tohyama
Tomoko
T
Yamashita
Kanae
K
D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage* / Q000378:metabolism; D001189:Aryl Hydrocarbon Hydroxylases; D001921:Brain / Q000378:metabolism; D002839:Chromans / Q000652:urine*; D051544:Cytochrome P-450 CYP3A; D065607:Cytochrome P-450 Enzyme Inhibitors; D007668:Kidney / Q000378:metabolism; D017705:Lignans / Q000494:pharmacology*; D008099:Liver / Q000378:metabolism; D008297:Male; D010089:Oxidoreductases, N-Demethylating / Q000037:antagonists & inhibitors; D029601:Pedaliaceae; D011422:Propionates / Q000652:urine*; D051381:Rats; D017208:Rats, Wistar; D012639:Seeds; D012715:Sesame Oil; D013997:Time Factors; D024504:gamma-Tocopherol / Q000008:administration & dosage* / Q000378:metabolism / Q000652:urine
D000975:Antioxidants; D002839:Chromans; D065607:Cytochrome P-450 Enzyme Inhibitors; D017705:Lignans; D011422:Propionates; C107690:2,7,8-trimethyl-2-(beta-carboxyethyl)-6-hydroxychroman; D012715:Sesame Oil; D024504:gamma-Tocopherol; D001189:Aryl Hydrocarbon Hydroxylases; D051544:Cytochrome P-450 CYP3A; D010089:Oxidoreductases, N-Demethylating