Effect of sesaminol on plasma and tissue alpha-tocopherol and alpha-tocotrienol concentrations in rats fed a vitamin E concentrate rich in tocotrienols.

Abstract

We have shown that sesame lignans added to rat diet resulted in significantly greater plasma and tissue concentrations of alpha- and gamma-tocopherol concentrations in supplemented rats than in rats without supplementation. In the present studies we examined whether sesaminol, a sesame lignan, enhances tocotrienol concentrations in plasma and tissues of rats fed diets containing a tocotrienol-rich fraction of palm oil (T-mix). In Experiment 1, effects of sesaminol on tocotrienol concentrations in plasma, liver, and kidney were evaluated in rats fed diets containing 20 mg/kg of T-mix (20T) and 50 mg/kg of T-mix (50T) with or without 0.1% sesaminol. Although the T-mix contained 23% alpha-tocopherol, 22% alpha-tocotrienol, and 34% gamma-tocotrienol, alpha-tocopherol constituted most or all of the vitamin E in plasma and tissue (from 97% in kidney to 100% in plasma), with no or very little alpha-tocotrienol and no gamma-tocotrienol at all. Addition of sesaminol to the T-mix resulted in significantly higher plasma, liver, and kidney alpha-tocopherol concentrations compared to values for T-mix alone. Further, T-mix with sesaminol resulted in significantly higher alpha-tocotrienol concentrations in kidney, although the concentration was very low. In Experiment 2, we examined whether sesaminol caused enhanced absorption of alpha-tocopherol and alpha-tocotrienol in a dosage regimen supplying T-mix and sesaminol on alternating days and observed significantly higher levels of alpha-tocopherol and alpha-tocotrienol in rats fed sesaminol, even without simultaneous intake, compared to those in rats without sesaminol. In Experiment 3, alpha-tocopherol was supplied to the stomach with and without sesaminol, and alpha-tocopherol concentrations in the lymph fluid were measured. a-Tocopherol concentrations were not different between groups. These results indicated that sesaminol produced markedly higher alpha-tocopherol concentrations in plasma and tissue and significantly greater alpha-tocotrienol concentrations in kidney and various other tissues, but the concentrations of alpha-tocotrienol were extremely low compared to those of a-tocopherol (Exps. 1 and 2). However, the sesaminol-induced increases of a-tocopherol and a-tocotrienol concentrations in plasma and tissue were not caused by their enhanced absorption since sesaminol did not enhance their absorption.