Sesame Lignan Research

Bhaskaran S, Santanam N, Penumetcha M, Parthasarathy S. Inhibition of atherosclerosis in low-density lipoprotein receptor-negative mice by sesame oil. J Med Food. 2006 Winter;9(4):487-90.

Study Abstract
Department of Pathology, Louisiana State University, Health Sciences Center, New Orleans, LA, USA.

Diet has profound effects on the development of atherosclerosis. Fatty acid composition, antioxidants, and other components such as lignans have major effects on the atherosclerotic process. Sesame oil has both mono- and polyunsaturated fatty acid constituents in equal proportions. In addition, it also has high levels of numerous antioxidants and inducers of peroxisome proliferator-activated receptor. The objective of this study was to determine the anti-atherosclerotic effects of sesame oil. In this study, male low-density lipoprotein (LDL) receptor (LDLR) -/- mice were fed atherogenic diet or atherogenic diet reformulated with the same level of sesame oil (sesame oil diet). Plasma lipids and atherosclerotic lesions were quantified after 3 months of feeding. Sesame oil-containing diet significantly reduced the atherosclerotic lesion formation and plasma cholesterol, triglyceride, and LDL cholesterol levels in LDLR -/- mice. These findings suggest that sesame oil could inhibit atherosclerosis lesion formation effectively, perhaps because of the synergistic actions of fatty acid and nonsaponifiable components.

Chen PR, Chien KL, Su TC. Dietary sesame reduces serum cholesterol and enhances antioxidant capacity in hypercholesterolemia. Nutr Res. 2005;25(6): 559-67.

Study Abstract
The purpose of the study was to investigate the effects of sesame on lowering serum lipids and enhancing antioxidant capacity in 21 hyperlipidemic patients. Subjects were instructed to consume their regular diet for 2 weeks before starting the experimental diet. The experimental diet with 40 g roasted sesame was consumed for 4 weeks and the regular diet followed for another 4 weeks. Body weights and fasting blood were determined at weeks 0, 4, and 8. The results showed that the diet with sesame significantly decreased the levels of serum total cholesterol and low-density lipoprotein (LDL) cholesterol. The time for erythrocyte hemolysis and the lag phase of LDL oxidation were significantly increased by sesame ingestion. A diet containing sesame slightly reduced the levels of thiobarbituric acid–reactive substances in LDL. The beneficial effects of sesame disappeared when patients returned to their regular diets. Sesame in this study appeared to exert beneficial effects on serum lipids and to improve antioxidant capacity in hypercholesterolemic patients.

Hirose N, Inoue T, Nishihara K, et al. Inhibition of cholesterol absorption and synthesis in rats by sesamin. J Lipid Res. 1991 May;32(4):629-38.

Study Abstract
Laboratory of Nutrition Chemistry, Kyushu University School of Agriculture, Fukuoka, Japan.

The effects of sesamin, a lignan from sesame oil, on various aspects of cholesterol metabolism were examined in rats maintained on various dietary regimens. When given at a dietary level of 0.5% for 4 weeks, sesamin reduced the concentration of serum and liver cholesterol significantly irrespective of the presence or absence of cholesterol in the diet, except for one experiment in which the purified diet free of cholesterol was given. On feeding sesamin, there was a decrease in lymphatic absorption of cholesterol accompanying an increase in fecal excretion of neutral, but not acidic, steroids, particularly when the cholesterol-enriched diet was given. Sesamin inhibited micellar solubility of cholesterol, but not bile acids, whereas it neither bound taurocholate nor affected the absorption of fatty acids. Only a marginal proportion (ca. 0.15%) of sesamin administered intragastrically was recovered in the lymph. There was a significant reduction in the activity of liver microsomal 3-hydroxy-3-methylglutaryl coenzyme A reductase after feeding sesamin, although the activity of hepatic cholesterol 7 alpha-hydroxylase, drug metabolizing enzymes, and alcohol dehydrogenase remained uninfluenced. Although the weight and phospholipid concentration of the liver increased unequivocally on feeding sesamin, the histological examination by microscopy showed no abnormality, and the activity of serum GOT and GPT remained unchanged. Since sesamin lowered both serum and liver cholesterol levels by inhibiting absorption and synthesis of cholesterol simultaneously, it deserves further study as a possible hypocholesterolemic agent of natural origin.

Ikeda S, Kagaya M, Kobayashi K, et al. Dietary sesame lignans decrease lipid peroxidation in rats fed docosahexaenoic acid. J Nut Sci Vitaminol (Tokyo). 2003 Sep;49(4):270-6.

Study Abstract
Department of Food and Nutrition, Sugiyama Jogakuen University, Nagoya 464-8662, Japan.

We have previously reported that dietary sesamin and sesaminol, major lignans of sesame seed, elevate the alpha-tocopherol concentration and decrease the thiobarbituric acid reactive substance (TBARS) concentration in the plasma and liver of rats. In this study, the effects of dietary sesamin and sesaminol on the lipid peroxidation in the plasma and tissues of rats fed docosahexaenoic acid (DHA, 22:6 n-3) were examined. Male Wistar rats (4-wk-old) were divided into the following six experimental groups: control group, fed a basal diet: sesamin group, fed a diet with sesamin (2 g/kg); sesaminol group, fed a diet with sesaminol (2 g/kg); DHA group, fed a diet containing DHA (5 g/kg); DHA + sesamin group, fed a diet containing DHA with sesamin; and DHA + sesaminol group, fed a diet containing DHA with sesaminol. Each diet contained either 0.01 or 0.05 g D-alpha-tocopherol/kg, and the rats were fed the respective experimental diet for 5 wk. The dietary DHA elevated the TBARS concentration and also increased the red blood-cell hemolysis induced by the dialuric acid. The dietary sesamin and sesaminol lowered the TBARS concentrations and decreased the red blood hemolysis. The dietary sesamin and sesaminol elevated the alpha-tocopherol concentrations in the plasma, liver, and brain of the rats fed a diet with or without DHA. These results suggest that dietary sesame lignans decrease lipid peroxidation as a result of elevating the alpha-tocopherol concentration in rats fed DHA.

Kang MH, Kawai Y, Naito M, Osawa T. Dietary defatted sesame flour decreases susceptibility to oxidative stress in hypercholesterolemic rabbits. J Nutr. 1999 Nov;129(10):1885-90.

Study Abstract
Laboratory of Food and Biodynamics, Nagoya University Graduate School of Bioagricultural Sciences, Nagoya 464-8601, Japan.

Plant glucosides possess antioxidative properties due to their ability to scavenge free radicals. Sesame seeds contain a class of these compounds, the sesaminol glucosides. To evaluate their antioxidative activity in vivo, we fed rabbits diets containing 1% cholesterol (Chol) with or without 10% defatted sesame flour (DSF) (containing 1% sesaminol glucosides) for 90 d. We determined the susceptibility of their tissues to oxidation ex vivo as well as serum total cholesterol (TC), phospholipid (PL), triglyceride (TG) and HDL cholesterol (HDL-C) concentrations. Serum TC, HDL-C, PL and TG levels were unaffected by the addition of DSF. The HDL-C in the Chol + DSF group was greater than in the Chol group at 45 d. Both were greater than in the groups that did not consume cholesterol. Liver TC and TG were significantly lower in rabbits fed the diet containing DSF plus 1% cholesterol than in those fed 1% cholesterol alone. Lipid peroxidation activity, measured as 2-thiobarbituric acid reactive substances (TBARS), was lower in the liver (P < 0.05) and serum (P = 0.06) of rabbits fed DSF plus cholesterol than in rabbits fed the cholesterol diet. Although we did not detect sesaminol glucosides in peripheral tissues, we observed abundant quantities of sesaminol in rabbits fed DSF, the principal metabolite. Our findings suggest that feeding DSF to rabbits does not protect cholesterol-induced hypercholesterolemia, but may decrease susceptibility to oxidative stress in rabbits fed cholesterol, perhaps due to the antioxidative activity of sesaminol.

Nakabayashi A, Kitagawa Y, Suwa Y, et al. Alpha-tocopherol enhances the hypocholesterolemic action of sesamin in rats. Int J Vitam Nutr Res. 1995;65(3):162-8.

Study Abstract
Institute for Biomedical Research, Suntory Ltd., Osaka, Japan.

The effect of alpha-tocopherol on the hypocholesterolemic action of sesamin was examined in rats given a cholesterol-enriched diet. When different levels (0.05 and 0.2%) of sesamin were fed, the supplementation of 1% alpha-tocopherol significantly accentuated the hypocholesterolemic action of sesamin, particularly with the higher sesamin level, although alpha-tocopherol alone did not affect the concentration of serum cholesterol. The dose-dependent promoting effect of alpha-tocopherol on the hypocholesterolemic action of sesamin was confirmed by supplementing different levels (0.2 and 1%) of alpha-tocopherol to a fixed level of sesamin (0.2%). alpha-Tocopherol was still effective at the 0.2% level. The metabolism of sesamin in the liver S9 fraction appeared to be interfered with alpha-tocopherol in vitro, suggesting a possible role of alpha-tocopherol in maintenance of the availability of sesamin.

Sankar D, Sambandam G, Ramakrishna RM, Pugalendi KV. Modulation of blood pressure, lipid profiles and redox status in hypertensive patients taking different edible oils. Clin Chim Acta. 2005 May;355(1-2):97-104.

Study Abstract
Department of Biochemistry, Faculty of Science, Annamalai University, Annamalainagar-608 002, Tamilnadu, India. [email protected]

BACKGROUND: Free oxygen radicals and insufficiency of antioxidants have been implicated in the pathogenesis of hypertension. We determined the effect of edible oils on blood pressure, lipid profiles and redox status in hypertensive patients given antihypertensive therapy (nifedipine-calcium channel blocker). METHODS: 530 patients medicated with nifedipine were divided into 3 groups (356 patients-sesame oil; 87 patients-sunflower oil; 47 patients-groundnut oil) and the control group (n=40) received only the drug, nifedipine. The respective oils were supplied to the patients and instructed to use as the only edible oil for 60 days, which comes to 35 g of oil/day/person. Blood pressure, lipid profiles [total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C) and triglycerides (TG)], lipid peroxidation [thiobarbituric acid reactive substances (TBARS)], enzymatic [superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)] and nonenzymatic [(vitamin C, vitamin E, beta-carotene and reduced glutathione (GSH)] in blood were measured at baseline and after 60 days of oil substitution. RESULTS: Patients with nifedipine alone or with respective oils had significantly lowered blood pressure. TC, LDL-C and TG decreased while HDL-C elevated in sesame and sunflower oil groups. Increases of HDL-C and TG were noted in groundnut oil group. TBARS levels reduced in all the groups whereas the reduction was remarkable in sesame oil group. Activities of SOD elevated in the 3 oil groups whereas GPx and CAT increased only in sesame oil group. Levels of vitamin C, vitamin E, beta-carotene and GSH increased in sesame oil group whereas vitamin E and beta-carotene were elevated only in sunflower and groundnut oil groups. GSH increased in drug control group also. CONCLUSION: Among the 3 oils, sesame oil offers better protection over blood pressure, lipid profiles and lipid peroxidation and increases enzymatic and nonenzymatic antioxidants.

Shimizu S, Akimoto K, Shinmen Y, et al. Sesamin is a potent and specific inhibitor of delta 5 desaturase in polyunsaturated fatty acid biosynthesis. Lipids. 1991 Aug;26(7):512-6.

Study Abstract
Department of Agricultural Chemistry, Kyoto University, Japan.

Incubation with sesame oil increases the mycelial dihomo-gamma-linolenic acid content of an arachidonic acid-producing fungus, Mortierella alpina, but decreases its arachidonic acid content [Shimizu, S., K. Akimoto, H. Kawashima, Y. Shinmen and H. Yamada (1989) J. Am. Oil Chem. Soc. 66, 237-241]. The factor causing these effects was isolated and identified to be (+)-sesamin. The results obtained in experiments with both a cell-free extract of the fungus and with rat liver microsomes demonstrated that (+)-sesamin specifically inhibits delta 5 desaturase at low concentrations, but does not inhibit delta 6, delta 9 and delta 12 desaturases. Kinetic analysis showed that (+)-sesamin is a noncompetitive inhibitor (Ki for rat liver delta 5 desaturase, 155 microM). (+)-Sesamolin, (+)-sesaminol and (+)-episesamin also inhibited only delta 5 desaturases of the fungus and liver. These results demonstrate that (+)-sesamin and related lignan compounds present in sesame seeds or its oil are specific inhibitors of delta 5 desaturase in polyunsaturated fatty acid biosynthesis in both microorganisms and animals.

Yamashita K, Ikeda S, Obayashi M. Comparative effects of flaxseed and sesame seed on vitamin E and cholesterol levels in rats. Lipids. 2003 Dec;38(12):1249-55

Study Abstract
Department of Food and Nutrition, Sugiyama Jogakuen University, School of Life Studies, Nagoya 464-8662, Japan. [email protected]

Flaxseed and sesame seed both contain more than 40% fat, about 20% protein, and vitamin E, mostly gamma-tocopherol. Furthermore, both contain considerable amounts of plant lignans. However, flaxseed contains 54% alpha-linolenic acid, but sesame seed only 0.6%, and the chemical structures of flaxseed and sesame lignans are different. In this study, we investigated the differential effects of flaxseed and sesame seed on plasma and tissue gamma-tocopherol, TBARS, and cholesterol concentrations. Rats were fed experimental diets for 4 wk: vitamin E-free, (-VE), gamma-tocopherol, flaxseed (FS), sesame seed (SS), flaxseed oil (FO), FO with sesamin (FOS), and defatted flaxseed (DFF). SS and FOS diets induced significantly higher gamma-tocopherol concentrations in plasma and liver compared with FS, FO, and DFF diets. Groups fed FS, FO, and FOS showed lower plasma total cholesterol compared with the SS and DFF groups. Higher TBARS concentrations in plasma and liver were observed in the FS and FO groups but not in the FOS group. These results suggest that sesame seed and its lignans induced higher gamma-tocopherol and lower TBARS concentrations, whereas flaxseed lignans had no such effects. Further, alpha-linolenic acid produced strong plasma cholesterol-lowering effects and higher TBARS concentrations.

Blood Vessels

Kita S, Matsumura Y, Morimoto S, et al. Antihypertensive effect of sesamin. II. Protection against two-kidney, one-clip renal hypertension and cardiovascular hypertrophy. Biol Pharm Bull. 1995 Oct;18(9):1283-5.

Study Abstract
Department of Pharmacology, Osaka University of Pharmaceutical Sciences, Japan.

We investigated the antihypertensive effect of sesamin, a lignan from sesame oil, using two-kidney, one-clip (2K,1C) renal hypertensive rats. After clipping the left renal artery, animals were assigned to either a normal diet group (control group) or a sesamin-containing (1% (w/w)) diet group (sesamin group). The sham-operated rats (sham group) were fed a normal diet and tap water. The systolic blood pressure of the control group increased progressively in comparison with the sham group. This 2K,1C-induced hypertension was markedly reduced by feeding the sesamin-containing diet. The systolic blood pressure after 4 weeks was 123.60 +/- 4.01 mmHg in the sham group, 187.43 +/- 5.69 mmHg in the control group and 145.57 +/- 6.78 mmHg in the sesamin group, respectively. There were significant increases in left ventricle plus septum weight-body weight ratio in the control group compared with the sham group. This rise was also significantly reduced in the sesamin group. When the thoracic aorta was histochemically evaluated, the wall thickness and wall-to-lumen ratio in the control group were significantly increased, compared with the sham group, indicating that vascular hypertrophy had occurred in the control group. The sesamin diet tended to ameliorate this vascular hypertrophy, although its effect was not statistically significant. These findings suggest that sesamin is useful as prophylactic treatment to combat the development of renal hypertension and cardiac hypertrophy.

Matsumura Y, Kita S, Morimoto S, et al. Antihypertensive effect of sesamin. I. Protection against deoxycorticosterone acetate- salt-induced hypertension and cardiovascular hypertrophy. Biol Pharm Bull. 1995 Aug;18(7):1016-9.

Study Abstract
Department of Pharmacology, Osaka University of Pharmaceutical Sciences, Osaka, Japan.

We investigated the antihypertensive effect of sesamin, a lignan from sesame oil, using deoxycorticosterone acetate (DOCA)-salt hypertensive rats. The animals were unilaterally nephrectomized, and then separated into a sham-operated group (sham group) and a DOCA-salt-treated group. The latter was further separated into a normal diet group (control group) and a sesamin-containing diet group (sesamin group). The systolic blood pressure of control group progressively increased in comparison with that of sham group. This DOCA-salt-induced hypertension was markedly suppressed by feeding a sesamin-containing diet. Systolic blood pressure after 5 weeks was 130.6 +/- 1.9 mmHg in the sham group, 198.1 +/- 7.3 mmHg in the control group and 152.5 +/- 8.4 mmHg in the sesamin group, respectively. The treatment with DOCA and salt for 5 weeks significantly increased the weight of the left ventricle plus the septum. However, this increase was significantly suppressed in the sesamin group. When the degree of vascular hypertrophy of the aorta and superior mesenteric artery was histochemically evaluated, there were significant increases in wall thickness, wall area and the wall-to-lumen ratio in the control group, compared with the sham. Sesamin feeding ameliorated the development of DOCA-salt-induced vascular hypertrophy in both the aorta and mesenteric artery. These findings strongly suggest that sesamin is useful as a prophylactic treatment in the development of hypertension and cardiovascular hypertrophy.

Matsumura Y, Kita S, Tanida Y, et al. Anti- hypertensive effect of sesamin. III. Protection against development and maintenance of hypertension in stroke-prone spontaneously hypertensive rats. Biol Pharm Bull. 1998 Jun;21(5):469-73.

Study Abstract
Department of Pharmacology, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan.

The antihypertensive effect of sesamin, a lignan from sesame oil, was examined using salt-loaded and unloaded stroke-prone spontaneously hypertensive rats (SHRSP). The animals at 6 weeks of age were separated into a salt-loaded group and an unloaded group. Salt-loaded animals were maintained on 1% NaCl drinking water. Each group was further divided into two groups: normal-diet group and sesamin-diet group. Systolic blood pressure of all animals was monitored once weekly. At the end of the feeding periods, cardiovascular hypertrophy and renal damage were evaluated. In the salt-loaded group, sesamin feeding significantly suppressed the development of hypertension, and efficient suppression was maintained from 9 to 26 weeks (e.g., 215+/-4 vs. 180+/-4 mmHg, at 17 weeks old). The left ventricle plus septum weight-to-body weight ratio was slightly but significantly lowered by sesamin feeding. When the degree of vascular hypertrophy of the aorta and superior mesenteric artery was histochemically evaluated, wall thickness and wall area of these vessels were significantly decreased by the sesamin feeding. Histological renal damage such as thickening of the tunica intima and fibrinoid degeneration of the arterial wall were often observed in the normal-diet group, but this damage was efficiently reduced in the sesamin-fed animals. On the other hand, in the salt-unloaded group, only a slight and nonsignificant suppressive effect of sesamin on the development of hypertension was observed. Although the wall area of the aorta was significantly decreased by the sesamin feeding, other vascular parameters were not ameliorated. The incidence of histological renal damage tended to decrease in sesamin-fed animals, but these alterations were not statistically significant. Thus, sesamin feeding was much more effective as an antihypertensive regimen in salt-loaded SHRSP than in unloaded SHRSP, thereby suggesting that sesamin is more useful as a prophylactic treatment in the malignant status of hypertension and/or hypertension followed by water and salt retention.

Matsumura Y, Kita S, Ohgushi R, Okui T. Effects of sesamin on altered vascular reactivity in aortic rings of deoxycorticosterone acetate-salt-induced hypertensive rat. Biol Pharm Bull. 2000 Oct;23(9):1041-5.

Study Abstract
Department of Pharmacology, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan. [email protected]

The effect of sesamin, a lignan from sesame oil, on altered vasodilator and vasoconstrictor responses in aortic rings from deoxycorticosterone acetate (DOCA)-salt-induced hypertensive rats, were examined. The systolic blood pressure after 5-weeks DOCA-salt treatment was 195.0+/-2.8 mmHg, which was much higher than that of sham-operated control animals (131.2+/-2.4 mmHg). Sesamin feeding significantly suppressed the development of this hypertension (167.1+/-8.6 mmHg). Acetylcholine (ACh)-induced endothelium-dependent relaxation of aortic rings was markedly decreased in the DOCA-salt hypertensive animals, compared with cases of the control (pD2, 7.0+/-0.1; maximal response, 64.8+/-3.4% versus pD2, 7.7+/-0.2; maximal response, 93.3+/-2.7%). These changes were partially but significantly improved by the sesamin feeding. This improvement seems to be related to a nitric oxide (NO)-dependent component of ACh-induced action, because sesamin feeding did not affect the responses to ACh in the presence of NO synthase inhibitor. A spontaneous NO releaser (+/-)-(E)-4-ethyl-2-[(E)-hydroxyimino]-5-nitro-3-hexenamide (NOR 3) which exerts endothelium-independent vasodilatation, produced the same patterns of responses as those observed with ACh in cases of DOCA-salt treatment and sesamin feeding. Phenylephrine-induced vasoconstriction was enhanced by the DOCA-salt treatment, both in preparations with and without endothelium, but these enhancements were almost completely normalized by sesamin feeding. Thus, dietary sesamin could efficiently improve the abnormal vasodilator and vasoconstrictor responses in DOCA-salt hypertensive animals. These effects may contribute to the antihypertensive activity of sesamin.

Nakano D, Kwak CJ, Fujii K, et al. Sesamin metabolites induce an endothelial nitric oxide-dependent vasorelaxation through their antioxidative property-independent mechanisms: possible involvement of the metabolites in the antihypertensive effect of sesamin. J Pharmacol Exp Ther. 2006 Jul;318(1):328-35.

Study Abstract
Department of Pharmacology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094 Japan.

Sesamin, a major lignan in sesame seeds and oil, has been known to lower blood pressure in several types of experimental hypertensive animals. A recent study demonstrated that sesamin metabolites had in vitro radical-scavenging activities. Thus, we determined whether the antioxidative effect of sesamin metabolites modulate the vascular tone and contribute to the in vivo antihypertensive effect of sesamin. We used four demethylated sesamin metabolites: SC-1m (piperitol), SC-1 (demethylpiperitol), SC-2m [(1R,2S,5R,6S)-6-(4-hydroxy-3-methoxyphenyl)-2-(3,4-dihydroxyphenyl)-3,7-dioxabicyclo[3,3,0]octane], and SC-2 [(1R,2S,5R, 6S)-2,6-bis(3,4-dihydroxyphenyl)-3,7-dioxabicyclo-[3,3,0]octane]. SC-1, SC-2m, and SC-2, but not SC-1m, exhibited potent radical-scavenging activities against the xanthine/xanthine oxidase-induced superoxide production. On the other hand, SC-1m, SC-1, and SC-2m produced endothelium-dependent vasorelaxation in phenylephrine-precontracted rat aortic rings, whereas SC-2 had no effect. The SC-1m- and SC-1-induced vasorelaxations were markedly attenuated by pretreatment with a nitric oxide synthase (NOS) inhibitor, NG-nitro-L-arginine (NOARG), or a soluble guanylate cyclase inhibitor, 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one. Neither SC-1m nor SC-1 changed the expression level of endothelial NOS protein in aortic tissues. The antihypertensive effects of sesamin feeding were not observed in chronically NOARG-treated rats or in deoxycorticosterone acetate-salt-treated endothelial NOS-deficient mice. These findings suggest that the enhancement of endothelium-dependent vasorelaxation induced by sesamin metabolites is one of the important mechanisms of the in vivo antihypertensive effect of sesamin.

Nakano D, Itoh C, Takaoka M, et al. Antihypertensive effect of sesamin. IV. Inhibition of vascular superoxide production by sesamin. Biol Pharm Bull. 2002 Oct;25(9):1247-9.

Study Abstract
Department of Pharmacology, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan.

We previously demonstrated the preventive effect of sesamin, a lignan from sesame oil, on the development of several experimental models of hypertension. In the present study, we explored the mechanisms underlying the antihypertensive effect of sesamin using the deoxycorticosterone acetate (DOCA)-salt rat hypertensive model. After a 5-week treatment period, aortic superoxide (O2-) production was measured in the lucigenin chemiluminescence assay. Chemiluminescence signals significantly decreased in sesamin-containing diet-fed DOCA-salt hypertensive rats compared with those in the normal diet-fed DOCA-salt rats, although the signals in sham-operated control animals were not affected by the sesamin feeding. In addition, there was a positive correlation between systolic blood pressure and aortic O2- production. These findings suggest that sesamin feeding inhibits enhanced vascular O2- production in DOCA-salt hypertensive rats and that the antioxidative action of sesamin may contribute to its antihypertensive activity.

Nakano D, Itoh C, Ishii F, et al. Effects of sesamin on aortic oxidative stress and endothelial dysfunction in deoxycorticosterone acetate-salt hypertensive rats. Biol Pharm Bull. 2003;26(12):1701-5.

Study Abstract
Department of Pharmacology, Osaka University of Pharmaceutical Sciences, Takatsuki, Osaka, Japan.

In the present study, we evaluated the relationship between the antihypertensive effect of sesamin, a lignan from sesame oil, and its antioxidative activity in deoxycorticosterone acetate (DOCA)-salt hypertensive rats. After a 5-week treatment period, systolic blood pressure was significantly elevated in normal diet-fed DOCA-salt animals compared with cases in sham-operated animals. Sesamin feeding, tempol (a superoxide dismutase mimetic) treatment or antihypertensive drugs combination (triple therapy; reserpine, hydralazine, hydrochlorothiazide) significantly suppressed the development of DOCA-salt-induced hypertension. Compared with sham-operated rats, the normal diet-fed DOCA-salt rats revealed marked increases in aortic superoxide (O(2)(-)) production. These increases in O(2)(-) production were significantly suppressed by sesamin feeding or tempol treatment, but not by triple therapy. Acetylcholine (Ach)-induced endothelium-dependent relaxation was markedly decreased in normal diet-fed DOCA-salt rats, compared with cases in sham-operated rats. Sesamin feeding and triple therapy significantly improved the DOCA-salt-induced impairment of endothelium-dependent relaxation. However, tempol treatment had no effect on the impaired vasodilator responses induced by DOCA-salt treatment. In DOCA-salt rats with or without sesamin feeding, systolic blood pressure significantly correlated with both aortic O(2)(-) production and endothelium-dependent vascular relaxation. These findings suggest that sesamin feeding inhibits the enhancement of aortic O(2)(-) production in DOCA-salt hypertensive rats, and this effect may contribute to the antihypertensive effect of sesamin. Sesamin feeding-induced improvement of endothelial dysfunction seems to result from the above antioxidative and antihypertensive effects.

Sankar D, Sambandam G, Rao MR, Pugal- endi KV. Impact of sesame oil on nifedipine in modulating oxidative stress and electrolytes in hypertensive patients. Asia Pac J Clin Nutr. 2004;13(Suppl):S107.

Study Abstract
The aim of the study was to investigate the effect of sesame oil as sole edible oil in hypertensive patients who were on medication with nifedipine, a calcium channel blocker. A sample of 396 hypertensive patients (aged 58 +/- 3.8 years; 215 men and 181 women) participated in this study. Forty patients were treated only with nifedipine while three hundred and fifty six patients were treated with nifedipine and instructed to use sesame oil in place of other edible oils for 60 days. The consumption of sesame oil remarkably reduced the (systolic and diastolic blood pressure from 166 +/- 4.2 and 101 +/- 3.1 to 134.2 +/- 3.4 and 84.6 +/- 3.0 respectively) blood pressure. The dosage of the drug also reduced, as there was a fall in blood pressure during sesame oil consumption. Plasma levels of sodium decreased while potassium and chloride increased significantly. Lipid peroxidation (thiobarbituric acid reactive substances) level significantly decreased while activities of enzymic (superoxide dismutase, glutathione peroxidase and catalase) and concentrations of non-enzymic antioxidants (vitamin C, vitamin E, beta-carotene and reduced glutathione) increased in nifedipine - sesame oil group. Nifedipine group showed a significant reduction in blood pressure, lipid peroxidation and improvement in reduced glutathione, however, the values are significantly lower than nifedipine - sesame oil group. These results suggest that dietary substitution of sesame oil, in nifedipine-taking hypertensive patients, has an additive effect in the reduction of blood pressure and plays an important role in the modulation of electrolytes and in the reduction of lipid peroxidation and elevation of antioxidants.