Dietary sesame seed decreases urinary excretion of alpha- and gamma-tocopherol metabolites in rats.
We previously showed that dietary sesame seed and its lignan inhibited gamma-tocopherol metabolism to 2,7,8-trimethyl-2(2'-carboxyethyl)-6-hydroxychroman (gamma-CEHC), a gamma-tocopherol metabolite, and markedly elevated tissue gamma-tocopherol concentration in rats. The aim of this study was to clarify the effect of dietary sesame seed on alpha-tocopherol metabolism. Vitamin E-deficient rats fed a vitamin E-free diet for 4 wk were fed a diet containing alpha-tocopherol, alpha- and gamma-tocopherol, or alpha-tocopherol with sesame seed for 7 d. Urinary excretion of 2,5,7,8-tetramethyl-2(2'-carboxyethyl)-6-hydroxychroman (alpha-CEHC), a alpha-tocopherol metabolite, in rats fed alpha-tocopherol with sesame seed was inhibited (p<0.05) as compared with that in rats fed alpha-tocopherol alone, or alpha- and gamma-tocopherol. The gamma-CEHC excretion was also less (p<0.05) in rats fed alpha-tocopherol with sesame seed than that in rats fed alpha- and gamma-tocopherol. The inhibition of alpha- and gamma-CEHC excretion by sesame seed was accompanied by elevation (p<0.05) of the alpha- and gamma-tocopherol concentration in the liver. These results suggest that dietary sesame seed inhibits not only gamma-tocopherol metabolism to gamma-CEHC but also alpha-tocopherol metabolism to alpha-CEHC in rats.
Uchida
Tomono
T
Department of Nutritional Sciences, Nagoya University of Arts and Sciences, Nissin, Japan.
Ichikawa
Tomio
T
Abe
Chisato
C
Yamashita
Kanae
K
Ikeda
Saiko
S
D000818:Animals; D002839:Chromans / Q000652:urine*; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D008297:Male; D011422:Propionates / Q000652:urine*; D051381:Rats; D017208:Rats, Wistar; D012639:Seeds; D031685:Sesamum; D024502:alpha-Tocopherol / Q000037:antagonists & inhibitors / Q000097:blood / Q000378:metabolism*; D024504:gamma-Tocopherol / Q000037:antagonists & inhibitors / Q000097:blood / Q000378:metabolism*
D002839:Chromans; D011422:Propionates; C107690:2,7,8-trimethyl-2-(beta-carboxyethyl)-6-hydroxychroman; C084852:2,5,7,8-tetramethyl-2-(2'-carboxyethyl)-6-hydroxychroman; D024504:gamma-Tocopherol; D024502:alpha-Tocopherol