Dietary Sesame Seed and Its Lignan Increase Both Ascorbic Acid Concentration in Some Tissues and Urinary Excretion by Stimulating Biosynthesis in Rats

Abstract

SummaryWe previously showed that the intake of sesamin, a major lignan in sesame seed, decreased lipid peroxidation and elevated tocopherol concentration in rat tissues. In this study, we examined the effect of dietary sesame seed and sesamin on the ascorbic acid concentration in rat tissues. Rats (4-wk-old) were fed either a vitamin E-free diet, or a diet containing 50 mg ␥ -tocopherol/kg, one containing 2 g sesamin/kg, one containing 50 mg ␥ -tocopherol/kg and 2 g sesamin/kg, or one containing 200 g sesame seed/kg for 28 d. The dietary sesamin and sesame seed elevated ascorbic acid concentrations in the liver and kidney, and increased urinary excretion in those Wistar rats. The dietary sesamin also elevated the hepatic mRNA levels of cytochrome P450 (CYP) 2B, and UDP-glucuronosyltransferase (UGT) 1A and 2B. In contrast, neither the sesamin nor the sesame seed affected the liver concentration of ascorbic acid in ODS rats with a hereditary defect in ascorbic acid synthesis, though the dietary sesame seed elevated the UGT1A and 2B mRNA levels in the liver. In addition, the sesame seed elevated the ␥ -tocopherol concentration in the various ODS rat tissues and the ascorbic acid concentrations in the kidney, heart and lung, while reducing the thiobarbituric acid reactive substance concentration in the heart and kidney. These results suggest that dietary sesame seed and its lignan stimulate ascorbic acid synthesis as a result of the induction of UGT1A and the 2B-mediated metabolism of sesame lignan in rats. The data of ODS rat studies also suggest that dietary sesame seed enhances antioxidative activity in the tissues by elevating the levels of two antioxidative vitamins, vitamin C and E. Key Words ascorbic acid, sesamin, sesame seed, UDP-glucuronosyltransferase, vitamin C Dietary sesame seed or its lignan, such as sesamin and sesaminol, elevates tocopherol concentration in the serum and tissues of rats fed tocopherol ( 1 -5 ). Dietary sesame lignan elevates the tocopherol concentration in tissues by inhibiting tocopherol metabolism to its metabolite because the dietary sesamin or sesaminol markedly decreases the urinary excretion of 2,7,8-trimethyl-2(2 ′ -carboxyethyl)-6-hydroxychroman ( ␥ -CEHC), a major metabolite of ␥ -tocopherol, in rats fed a diet containing ␥ -tocopherol ( 4 ). We also showed that the concentration of thiobarbituric acid reactive substance (TBARS) in the tissues and plasma (or serum) was decreased by dietary sesame seed or its lignan ( 1 , 2 , 4 , 5 ). It was recently reported that dietary sesame seed or sesame oil consumption reduced the urinary excretion of ␥ -CEHC ( 6 ), elevated the plasma (or serum) ␥ -tocopherol concentration ( 7-9 ), and decreased serum TBARS concentration ( 9 ) in humans. These data suggest that dietary sesame lignan elevates tocopherol concentration in the serum and tissues by inhibiting its metabolism, and decreases lipid peroxidation by inducing a high tocopherol concentration in humans and rats.

Antihypertensive and antioxidant effects of dietary black sesame meal in pre-hypertensive humans

“…The accumulation of vitamin E acts by detoxifying the hydroxyl and proxy radicals, leading to reduced lipid peroxidation, or by reducing excess tissue aldehydes [ 11 ]. This is supported by many previous studies, in which supplementation of either vitamin E or sesamin and sesamolin demonstrated that these antioxidants inhibit lipid peroxidation [ 3 - 7 , 25 ]. The antioxidant effect is likely to contribute to the decreased endothelial dysfunction from free radicals [ 26 ], resulting in an increase in the vasorelaxing factor, nitric oxide (NO) [ 27 ].…”

Metabolism of Sesamin by Cytochrome P450 in Human Liver Microsomes

“…Among the 11 kinds of the metabolites, mono-and dicatechol metabolites, which appear to be metabolized by P450s, are known to have high antioxidative activities (Nakai et al, 2003;Miyake et al, 2005). It was reported that sesamin elevated CYP2B and CYP4A mRNA levels in rats (Tsuruoka et al, 2005;Ikeda et al, 2007) and CYP1A activity in rainbow trout (Trattner et al, 2008). In addition, sesamin inhibited CYP4F2 to elevate tocopherol levels (Sontag and Parker, 2002).…”

Antihyperlipidemic Effect of Sesame (Sesamum indicum L.) Protein Isolate in Rats Fed a Normal and High Cholesterol Diet

“…They concluded that sesame ingestion benefits postmenopausal women by improving blood lipids, antioxidant status, and possibly sex hormone status. Ikeda and others (2007) studied the effect of dietary sesame seed and sesamin on the ascorbic acid concentration in rat tissues. The dietary sesame seeds and sesamin elevated ascorbic acid concentrations in the liver and kidney and increased urinary excretion in those Wistar rats.…”