Antihypertensive effect of sesamin. II. Protection against two-kidney, one-clip renal hypertension and cardiovascular hypertrophy

Sesamin's Therapeutic Actions on Cyclophosphamide-Induced Hepatotoxicity, Molecular Mechanisms, and Histopathological Characteristics

Cyclophosphamide, an alkylating agent integral to specific cancer chemotherapy protocols, is often curtailed in application owing to its significant hepatotoxic side effects. Therefore, this study was conducted to assess the hepatoprotective potential of sesamin, a plant-originated antioxidant, using rat models. The rats were divided into five groups: a control group received only the vehicle for six days; a cyclophosphamide group received an intraperitoneal (i.p.) single injection of cyclophosphamide (150 mg/kg) on day four; a sesamin group received a daily high oral dose (20 mg/kg) of sesamin for six days; and two groups were pretreated with oral sesamin (10 and 20 mg/kg daily from day one to day six) followed by an i.p. injection of cyclophosphamide on day four. The final and last sesamin dose was administered 24 h before euthanasia. At the end of the experiment, blood and liver tissue were collected for biochemical and histopathological assessments. The results indicated significantly increased liver markers (AST, ALT, ALP, and BIL), cytokines (TNFα and IL-1β), caspase-3, and malondialdehyde (MDA) in the cyclophosphamide group as compared to the normal control. Additionally, there was a significant decline in antioxidants (GSH) and antioxidant enzymes (CAT and SOD), but the sesamin treatment reduced liver marker enzymes, cytokines, and caspase-3 and improved antioxidants and antioxidant enzymes. Thus, sesamin effectively countered these alterations and helped to normalize the histopathological alterations. In conclusion, sesamin demonstrated the potential for attenuating cyclophosphamide-induced hepatotoxicity by modulating cytokine networks, apoptotic pathways, and oxidative stress, suggesting its potential role as an adjunct in chemotherapy to reduce hepatotoxicity.

Effects of sesame (Sesamum indicum L.) and bioactive compounds (sesamin and sesamolin) on inflammation and atherosclerosis: A review

Inflammation, oxidative stress, obesity, infection, hyperlipidemia, hypertension, and diabetes are the main causes of atherosclerosis, which in the long term lead to hardening of the arteries. In the current study, we reviewed recent findings of the mechanism of sesame and its active compounds of sesamin and sesamolin regulates on atherosclerosis. Sesame can decrease the lipid peroxidation and affect the enzymes, which control the balance of oxidative status in the body. Besides modulating the inflammatory cytokines, sesame regulates the main mediators of the signaling pathways in the process of inflammation, such as prostaglandin E2 (PGE2), nuclear factor kappa light-chain enhancer of activated B cells (NF-kB) and peroxisome proliferator-activated receptor gamma (PPAR-γ). Sesame decreases the growth of different pathogens. It fights against obesity and helps to reduce weight, body mass index (BMI), waist circumference, and lipid count of serum and liver. In addition to lowering fasting blood sugar (FBS), it decreases the hemoglobin A1c (HbA1c) and glucose levels and improves insulin function. With high content of linoleic acid, α-linolenic acid, and total polyunsaturated fatty acid (PUFA), sesame efficiently controls the blood plasma lipids and changes the lipid profile. In the case of hypertension, it maintains the health of endothelium through multiple mechanisms and conserves the response of the arteries to vasodilation. PUFA in sesame suppresses blood clotting and fibrinogen activity. All the mentioned properties combat atherosclerosis and hardening of blood vessels, which are detailed in the present review for sesame.

The Protective Effects of Sesamin against Cyclophosphamide-Induced Nephrotoxicity through Modulation of Oxidative Stress, Inflammatory-Cytokines and Apoptosis in Rats

Cyclophosphamide is an anticancer drug with a wide spectrum of clinical uses, but its typical side effects are multiple complications, including nephron toxicity. The possible molecular mechanism of the nephroprotective action of sesamin (SM) against cyclophosphamide (CP) induced renal toxicity was investigated in rats by understanding oxidative stress and inflammatory cytokines. In this study, rats were arbitrarily grouped into the following four groups: a normal control group (CNT); a CP-induced toxicity group; a treatment group with two doses of sesamin SM10 and SM20; a group with sesamin (SM20) alone. A single dose of CP (150 mg/kg body, i.p.) was administered on day 4 of the experiments, while treatment with SM was given orally for seven days from day 1. The group treated with SM showed a significant protective effect against CP-induced renal damage in rats. Treatment with SM significantly increased the antioxidant enzymes (GSH, CAT, and SOD) and reduced malondialdehyde (MDA) levels. Thus, SM significantly overcame the elevated kidney function markers (creatinine, blood urea nitrogen, and uric acid) by attenuating oxidative stress. The SM also significantly reduced the elevated cytokines (IL-1β and TNFα) and caspase-3 in the treated group. Histopathological studies confirmed the protective effect of sesamin (SM) on CP-induced nephrotoxicity. In conclusion, the current findings support the nephroprotective effect of sesamin against CP-induced renal injury.

The effects of sesame, canola, and sesame-canola oils on cardiometabolic markers in patients with type 2 diabetes: a triple-blind three-way randomized crossover clinical trial

AIMS

To compare the effects of replacing regular dietary oils intake with sesame (SO), canola (CO), and sesame-canola (SCO) oils (a novel blend), on cardiometabolic markers in adults with type 2 diabetes mellitus (T2DM), in a triple-blind, three-way, randomized, crossover clinical trial.

METHODS

Participants were assigned to receive SO, CO, and SCO in three 9-week phases (4 weeks apart). Cardiometabolic makers (serum lipids, Apolipoprotein, cardiovascular risk scores, kidney markers, and blood pressure) were considered at the beginning and the end of intervention phases.

RESULTS

Ninety-two, ninety-five, and ninety-five participants completed the SO, SCO, and CO periods, respectively. After CO consumption, serum Apo A-1 concentrations were significantly higher compared with the SCO period in the whole population (p < 0.05). A considerable reduction in visceral adiposity index values was seen in the CO compared with the SO period in males (p < 0.05). Serum high-density lipoprotein concentration was also significantly higher after the SO intake compared with SCO in females (p < 0.05). The between-period analysis showed a substantial reduction in diastolic blood pressure in the SCO period compared with the CO and SO periods and lower systolic blood pressure after SCO versus CO intake in males (p < 0.05).

CONCLUSIONS

Canola oil might protect CVD through improving Apo A-1 levels in patients with T2DM (particularly in females) and visceral adiposity index in male patients. However, the blend oil might beneficially affect blood pressure in men. Future sex-specific studies might warrant the current findings.

REGISTRY OF CLINICAL TRIALS

This trial was registered in the Iranian Registry of Clinical Trials (IRCT, registration ID: IRCT2016091312571N6).

Electrocatalysis as a key strategy for the total synthesis of natural products

Electrochemical strategies have been a powerful approach for the synthesis of valuable intermediates, in particular heterocyclic motifs. Because of the mild nature, a wide range of nonclassical bond disconnections have been achieved via in situ-generated radical intermediates in a highly efficient manner. In particular, anodic electrochemical oxidative strategies have been utilized for the total synthesis of many structurally intriguing natural products. In this review article, we have discussed a number of total syntheses of structurally intriguing alkaloids and terpenoids in which electrochemical processes play an important role as a key methodology.

Nephrotonic and Nephroprotective medicinal herbs in traditional Persian Medicine: Review and assessment of scientific evidence

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The tendency to use herbal and complementary therapies has been increased dramatically in last decades. The aim of this study is reviewing nephrotonic and nephroprotective medicinal herbs in traditional Persian Medicine (TPM) historical books, and assessment of relevant scientific evidence and possible mechanisms of action. In this study, seven major references among pharmaceutical books of PM from the 11th to 19th centuries were selected and were searched with key words equivalent to “nephroprotection”. To find new studies, the scientific name of medicinal herbs which were repeated twice or more were searched using data bases including PubMed, and Google scholar with keywords of nephroprotective, renal disorder, renal failure and kidney. Also, probable effective mechanisms were explored with key words including oxidative stress, antioxidant, inflammation, anti-inflammatory and angiotensin-converting-enzyme inhibitor. 210 herbal remedies were found with kidney strengthening, nephroprotective, and atrophy prevention effects in reviewed books. The most repeated herbs were 41 Results of scientific evidence showed that the possible functional mechanisms of these plants include anti-inflammatory, anti-oxidative, blood pressure/glucose-lowering effect as well as improvement of glomerular filtration, prevention of tissue damage, and enhancing the reconstructive power of cells. The list of medicinal herbs in this study can be used as a base of future studies on production of new medicines for prevention or treatment of renal failure and for the enhancement of renal performance.

Health benefits of sesamin on cardiovascular disease and its associated risk factors

Sesamin, a major lignin isolated from sesame (Sesamum indicum) seeds and sesame oil, is known to possess antioxidant and anti-inflammatory properties. Several studies have revealed that oxidative stress and inflammation play a major role in a variety of cardiovascular diseases (CVDs). This comprehensive review summarizes the evidence on the effects of sesamin on CVD and its risk factors, principally due to its antioxidant properties. Specifically, this review highlights the mechanisms underlying the anti-hypertensive, anti-atherogenic, anti-thrombotic, anti-diabetic, and anti-obesity, lipolytic effects of sesamin both in vivo and in vitro, and identifies the signaling pathways targeted by sesamin and its metabolites. The data indicates that RAS/MAPK, PI3K/AKT, ERK1/2, p38, p53, IL-6, TNFα, and NF-κB signaling networks are all involved in moderating the various effects of sesamin on CVD and its risk factors. In conclusion, the experimental evidence suggesting that sesamin can reduce CVD risk is convincing. Thus, sesamin can be potentially useful as an adjuvant therapeutic agent to combat CVD and its multitude of risk factors.

Sesame lignans increase sympathetic nerve activity and blood flow in rat skeletal muscles

Beneficial effects of sesame lignans, especially antioxidative effects, have been widely reported; however, its potential effects on autonomic nerves have not yet been investigated. Therefore, the current study aimed to investigate the effect of sesame lignans on the autonomic nervous system. The sympathetic nerve activity in rat skeletal muscle was measured using electrophysiological approaches, with blood flow determined using the laser Doppler method. Sesame lignans were administered intragastrically at 2 and 20 mg/kg, and after 60 min, the sympathetic nerve activity was observed to increase by 45.2% and 66.1%, respectively. A significant increase in blood flow (39.6%) was also observed for the 20-mg/kg dose when measured at 55 min after administration. These sympathomimetic effects were completely prevented by subdiaphragmatic vagotomy, and the increase in blood flow was eliminated in the presence of the beta2-adrenergic receptor inhibitor butoxamine. Thus, it is proposed that sesame lignans can increase the blood flow of skeletal muscle, possibly by exciting sympathetic nerve activity through the afferent vagal nerve.

The effect of canola oil compared with sesame and sesame-canola oil on cardio-metabolic biomarkers in patients with type 2 diabetes: Design and research protocol of a randomized, triple-blind, three-way, crossover clinical trial

BACKGROUND

Both canola and sesame oils consumption have been associated with favorable effects on cardio-metabolic biomarkers. However, to the best of our knowledge, no study has compared their effects on cardiovascular risk factors. The present study aimed to assess the effect of canola, sesame, and sesame-canola oils consumption on cardio-metabolic biomarkers in patients with type 2 diabetes mellitus (T2DM).

METHODS

This study was a randomized, triple-blind, three-way, crossover clinical trial. The study participants included 102 individuals with T2DM. Their spouses were also included in the study. The participants were entered into a 4-week run-in period. After that, their regular dietary oil was replaced with canola, sesame, or sesame-canola oils (a blend of sesame and canola oils) in three 9-week phases, which were separated by two 4-week washout periods (sunflower oil was consumed during the run-in and the washout periods). Dietary, physical activity, blood pressure, and anthropometric measurements were assessed at the beginning, in the middle (week 4-5), and at the end of each treatment phase. Blood samples were taken at the beginning and at the end of each phase. Serum, plasma, buffy coat, and whole blood samples were extracted and kept at -80 ºC for further analysis. Serum fasting blood sugar (FBS), triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) were selected as the primary outcomes.

RESULTS

102 participants with T2DM were randomly assigned to one of the 6 rolling methods. Through them, 93 individuals (91.2%) completely participated in all phases.

CONCLUSION

The present study will provide an exceptional opportunity to examine the effect of canola, sesame, and sesame-canola oil on cardio-metabolic markers in adults with and without T2DM. This trial will also provide a good medium for the investigation of gene-dietary oils interaction in the future.

Sesamin Catechol Glucuronides Exert Anti-inflammatory Effects by Suppressing Interferon β and Inducible Nitric Oxide Synthase Expression through Deconjugation in Macrophage-like J774.1 Cells

Sesamin, a representative sesame lignan, has health-promoting activities. Sesamin is converted into catechol derivatives and further into their glucuronides or sulfates in vivo, whereas the biological activities of sesamin metabolites remain unclear. We examined the inhibitory effects of sesamin metabolites on the lipopolysaccharide (LPS)-induced nitric oxide (NO) production in mouse macrophage-like J774.1 cells and found that a monocatechol derivative SC1, (7α,7'α,8α,8'α)-3,4-dihydroxy-3',4'-methylenedioxy-7,9':7',9-diepoxylignane, has a much higher activity than sesamin and other metabolites. The inhibitory effects of SC1 glucuronides were time-dependently enhanced, associated with the intracellular accumulation of SC1 and the methylated form. SC1 glucuronides and SC1 attenuated the expression of inducible NO synthase (iNOS) and upstream interferon-β (IFN-β) in the LPS-stimulated macrophages. The inhibitory effects of SC1 glucuronides against NO production were canceled by the β-glucuronidase inhibitor and enhanced by the catechol-O-methyltransferase inhibitor. Our results suggest that SC1 glucuronides exert the anti-inflammatory effects by inhibiting the IFN-β/iNOS signaling through macrophage-mediated deconjugation.

Synthetic studies on optically active furofuran and diarylbutane lignans*

Lignans are a large class of naturally occurring secondary metabolites which are widely spread within the plant kingdom. Their diverse structures and variety of biological activities have fascinated organic chemists. For synthesizing optically active lignans, we have developed the novel asymmetric dimerization of cinnamic acid derivatives, and applied it to the enantioselective syntheses of furofuran lignans (yangambin, sesamin, eudesmin, caruilignan A) and diarylbutane lignans (sauriols A and B). This review summarizes the methodology of our asymmetric dimerization of cinnamic acid derivatives, and efficient total syntheses of furofuran and diarylbutane lignans reported by our and other groups.

Can sesame consumption improve blood pressure? A systematic review and meta-analysis of controlled trials

Hypertension is a major risk factor for cardiovascular disease, myocardial infarction, stroke and renal failure. Sesame consumption may benefit blood pressure (BP) owing to its high polyunsaturated fatty acid, fibre, phytosterol and lignan contents. To clarify this, a systematic review and meta-analysis of controlled trials was conducted. The PubMed (MEDLINE), Cumulative Index to Nursing and Allied Health Literature (CINAHL) and Cochrane Library (Central) databases were systematically searched until August 2016. Eight controlled trials with a total of 843 participants met the eligibility criteria. A random effect meta-analysis showed that sesame consumption can reduce systolic BP (-7.83 mmHg, 95% CI: -14.12, -1.54; P < 0.05, I²  = 99%) and diastolic BP (-5.83 mmHg, 95% CI: -9.58, -2.08; P < 0.01, I²  = 98%). To reduce the heterogeneity, the meta-analysis was limited to high methodology quality trials (n = 4), which resulted in a significant reduction in systolic BP (-3.23 mmHg, 95% CI: -5.67, -0.79; I²  = 33%) and a non-significant reduction in diastolic BP (-2.08 mmHg, 95% CI: -4.85, 0.69; I²  = 62%). This study concluded that sesame consumption can reduce systolic and diastolic BP. However, further investigations with larger sample sizes and better methodology quality are required to confirm the BP-lowering effect of sesame consumption. © 2017 Society of Chemical Industry.

Mechanisms of chromosomal aberrations induced by sesamin metabolites in Chinese hamster lung cells

Sesamin is a major lignan in sesame seeds and oil. We previously demonstrated that sesamin induces chromosomal aberrations (CA) in Chinese hamster lung (CHL/IU) cells in the presence of a metabolic activation system (S9 mix), although no genotoxicity was detected in vivo. To clarify the mechanism of CA induction by sesamin, we identified its principal active metabolite. A mono-catechol derivative, [2-(3,4-methylenedioxyphenyl)-6-(3,4-dihydroxyphenyl)-3,7-dioxabi-cyclo[3.3.0]octane (SC-1)], was previously identified in culture medium when sesamin was incubated with S9 mix. In the present study, we show that SC-1 induces CA in CHL/IU cells but not in human hepatoblastoma (HepG2) cells. SC-1 was unstable in culture medium. Addition of glutathione (GSH) to the incubation mixture decreased the rate of decomposition and also suppressed induction of CA in CHL/IU cells. These results indicate that SC-1 itself may not contribute to the induction of CA. Two GSH adducts of SC-1 were identified when SC-1 was incubated with GSH, suggesting that SC-1 was converted to the semiquinone/quinone form and then conjugated with GSH in the culture medium. Sodium sulfite (a quinone-responsive compound) also suppressed CA induction by SC-1. These findings strongly suggest that SC-1 is oxidized to semiquinone/quinone derivatives extracellularly in culture medium, that these derivatives are responsible for the induction of CA in CHL/IU cells, and therefore that the positive results obtained with sesamin in in vitro CA tests using CHL/IU cells may not be relevant to the assessment of in vivo activity.

Absorption, distribution, metabolism, and excretion of [14 C]sesamin in rats

SCOPE

Sesamin is a major lignan in sesame seeds and has various physiological effects. Although metabolism of sesamin by cytochrome P450 or intestinal microflora has been reported, little is known concerning the mass balance, pharmacokinetics, and tissue distribution of sesamin.

METHODS AND RESULTS

Absorption, distribution, metabolism, and excretion of [¹⁴ C]sesamin were investigated after a single oral dose of 5 mg/kg in rats. Sesamin was absorbed with peak plasma radioactivity at 1.0 h and declined with a terminal half-life 4.7 h. The cumulative excretion of radioactivity was 37.5 ± 3.1% in urine and 58.7 ± 4.8% in feces. In bile duct-cannulated rats, the cumulative excretion of radioactivity was 66.3 ± 8.4% in bile and 27.8 ± 10.2% in urine. Tissue distribution was investigated using quantitative whole-body autoradiography. Radioactivity was widely distributed over the whole body and was highly detected in the liver and kidney. The metabolites profile was examined using radiochromatography. Sesamin was mainly distributed in the form of conjugate metabolites.

CONCLUSIONS

Sesamin was absorbed efficiently and distributed over the whole body. In particular, sesamin was highly distributed in the form of the metabolites in the liver and kidney. The results of this study are useful in elucidating the action mechanism of sesamin.

Sesame fractions and lipid profiles: a systematic review and meta-analysis of controlled trials

Increased plasma lipid profiles are among the most important risk factors of CHD and stroke. Sesame contains considerable amounts of vitamin E, MUFA, fibre and lignans, which are thought to be associated with its plasma lipid-lowering properties. This study aimed to systematically review the evidence and identify the effects of sesame consumption on blood lipid profiles using a meta-analysis of controlled trials. PubMed, CINAHL and Cochrane Library databases were searched (from 1960 to May 2015). A total of ten controlled trials were identified based on the eligibility criteria. Both the Cochrane Collaboration tool and the Rosendal scale were used to assess the risk of bias of the included studies. The meta-analysis results showed that consumption of sesame did not significantly change the concentrations of total blood cholesterol (−0·32 mmol/l; 95 % CI −0·75, 0·11; P=0·14, I2=96 %), LDL-cholesterol (−0·15 mmol/l; 95 % CI −0·50, 0·19; P=0·39, I2=96 %) or HDL-cholesterol (0·01 mmol/l; 95 % CI −0·00, 0·02; P=0·16, I2=0 %). However, a significant reduction was observed in serum TAG levels (−0·24 mmol/l; 95 % CI −0·32, −0·15; P<0·001, I2=84 %) after consumption of sesame. It was concluded that sesame consumption can significantly reduce blood TAG levels but there is insufficient evidence to support its hypocholesterolaemic effects. Further studies are required to determine the potential effect of sesame consumption on lipid profiles and cardiovascular risk factors.

Sesamin enhances nitric oxide bioactivity in aortas of spontaneously hypertensive rats

BACKGROUND

The blood pressure lowering effect of sesamin has been demonstrated to be associated with the increase in vascular nitric oxide (NO) biological activity by our previous studies and others. The present study was designed to explore the underlying mechanisms involved in the effect of sesamin on aortic NO bioactivity in spontaneously hypertensive rats (SHRs).

METHODS

Sesamin was orally administered for 8 consecutive weeks in SHRs. Systolic blood pressure (SBP) was measured using the tail-cuff method. The aortas were isolated and in vitro vascular reactivity studies were performed. Superoxide anion production in carotid arteries was assessed by dihydroethidium fluorescence staining. The protein expression of endothelial nitric oxide synthase (eNOS), phosphorylated eNOS (P-eNOS), dihydrofolate reductase (DHFR), nicotinamide adenine dinucleotide phosphate oxidase subunit p47phox, and copper, zinc superoxide dismutase (Cu/Zn-SOD) in aortas was detected by Western blotting. The dimeric form of eNOS in aortas was determined by low-temperature sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Aortic level of nitrotyrosine and activities of antioxidant enzymes, namely, total SOD (T-SOD), glutathione peroxidase (GPx) and catalase were also detected.

RESULTS

In SHRs, sesamin treatment reduced SBP, improved vascular relaxation induced by acetylcholine and enhanced aortic NO bioactivity. Sesamin treatment enhanced NO biosynthesis in SHR aortas was due to upregulated P-eNOS and suppressed eNOS uncoupling, and the latter effect might be attributed to decreased nitrotyrosine and upregulated DHFR. Sesamin also reduced the NO oxidative inactivation and decreased the superoxide anion production through downregulation of p47(phox) and amelioration of eNOS uncoupling. In addition, sesamin treatment did not alter the levels of GPx and catalase activity but obviously reduced the compensatory elevated T-SOD activity and Cu/Zn-SOD protein expression.

CONCLUSION

Chronic treatment with sesamin could reduce hypertension and improve endothelial dysfunction through enhancement of NO bioactivity in SHR aortas.

Long-term intake of sesamin improves left ventricular remodelling in spontaneously hypertensive rats

This study was designed to evaluate the in vivo cardioprotective effects of food-derived sesamin in spontaneously hypertensive rats (SHR). The study was performed with 17-week-old male normotensive Wistar-Kyoto rats (WKY) and SHR which are untreated or treated with orally administered sesamin for 16 weeks before they were sacrificed. Long-term treatment with sesamin obviously improved left ventricular (LV) hypertrophy and fibrosis in SHR, as indicated by the decrease of LV weight/body weight, myocardial cell size, cardiac fibrosis and collagen type I expression as well as the amelioration of the LV ultrastructure. These effects were associated with reduced systolic blood pressure, enhanced cardiac total antioxidant capability and decreased malondialdehyde content, nitrotyrosine level and transforming growth factor β1 (TGF-β1) expression. All these results suggest that chronic treatment with sesamin improves LV remodeling in SHR through alleviation of oxidative and nitrative stress, reduction of blood pressure and downregulation of TGF-β1 expression.

Sesamin ameliorates arterial dysfunction in spontaneously hypertensive rats via downregulation of NADPH oxidase subunits and upregulation of eNOS expression

AIM

Sesamin is one of the major lignans in sesame seeds with antihyperlipidemic, antioxidative and antihypertensive activities. The aim of this study was to examine the effects of sesamin on arterial function in spontaneously hypertensive rats (SHRs).

METHODS

SHRs were orally administered sesamin (40, 80 and 160 mg·kg(-1)·d(-1)) for 16 weeks. After the rats were killed, thoracic aortas were dissected out. The vasorelaxation responses of aortic rings to ACh and nitroprusside were measured. The expression of eNOS and NADPH oxidase subunits p47(phox) and p22(phox) in aortas were detected using Western blotting and immunohistochemistry. Aortic nitrotyrosine was measured with ELISA. The total antioxidant capacity (T-AOC) and MDA levels in aortas were also determined.

RESULTS

The aortic rings of SHRs showed significantly smaller ACh-induced and nitroprusside-induced relaxation than those of control rats. Treatment of SHRs with sesamin increased both the endothelium-dependent and endothelium-independent relaxation of aortic rings in a dose-dependent manner. In aortas of SHRs, the level of T-AOC and the expression of nitrotyrosine, p22(phox) and p47(phox) proteins were markedly increased, while the level of MDA and the expression of eNOS protein were significantly decreased. Treatment of SHRs with sesamin dose-dependently reversed these biochemical and molecular abnormalities in aortas.

CONCLUSION

Long-term treatment with sesamin improves arterial function in SHR through the upregulation of eNOS expression and downregulation of p22(phox) and p47(phox) expression.

The sesame lignan sesamin attenuates vascular dysfunction in streptozotocin diabetic rats: involvement of nitric oxide and oxidative stress

The effect of chronic administration of sesamin was studied on aortic reactivity of streptozotocin diabetic rats. Male diabetic rats received sesamin for 7 weeks after diabetes induction. Contractile responses to KCl and phenylephrine and relaxation response to acetylcholine were obtained from aortic rings. Maximum contractile response of endothelium-intact rings to phenylephrine was significantly lower in sesamin-treated diabetic rats relative to untreated diabetics and endothelium removal abolished this difference. Meanwhile, endothelium-dependent relaxation to acetylcholine was significantly higher in sesamin-treated diabetic rats as compared to diabetic ones and pretreatment of rings with nitric oxide synthase inhibitor N(G)-nitro-l-arginine methyl ester significantly attenuated the observed response. Two-month diabetes also resulted in an elevation of malondialdehyde and decreased superoxide dismutase activity and sesamin treatment significantly improved these changes. Therefore, chronic treatment of diabetic rats with sesamin could prevent some abnormal changes in vascular reactivity in diabetic rats through nitric oxide and via attenuation of oxidative stress and tissue integrity of endothelium is necessary for its beneficial effect.

Plasma and tissue concentrations of α-tocopherol and δ-tocopherol following high dose dietary supplementation in mice

Vitamin E isoforms are essential nutrients that are widely used as dietary supplements and therapeutic agents for a variety of diseases. However, their pharmacokinetic (PK) properties remain poorly characterized, and high dosage animal studies may provide further information on their in vivo functions and pharmacological effects. In this study, alpha-tocopherol (α-toc) and delta-tocopherol (δ-toc) levels were measured in mouse plasma and tissues following their high dosage dietary supplementation. Average α-toc levels at 5, 10 and 20 g α-toc/kg diet increased over baseline levels 6-fold in plasma, 1.6-fold in brain, and 4.9-fold in liver. These elevated α-toc concentrations remained constant from 5 to 20 g α-toc/kg diet, rather than showing further increases across these dosages. No α-toc-related toxicity occurred at these high dosages, and strain-specific differences in liver and brain α-toc levels between Balb/cJ and C57Bl/6J mice were observed. Relatively high-dosage administration of dietary δ-toc for 1 or 4 weeks resulted in 6-30-fold increases in plasma and liver levels between dosages of 0.33 and 1.67 g δ-toc/kg diet. Co-administration of sesamin with δ-toc further increased δ-toc levels between 1.3- and 14-fold in plasma, liver, and brain. These results provide valuable PK information on high dosage α-toc and δ-toc in mouse and show that supplementation of sesamin with δ-toc further increases δ-toc levels over those seen with δ-toc supplementation alone.

Sesamin exerts renoprotective effects by enhancing NO bioactivity in renovascular hypertensive rats fed with high-fat-sucrose diet

In the present study, we aimed to evaluate the protective effect of sesamin on kidney damage and renal endothelial dysfunction in two-kidney, one-clip renovascular hypertensive rats fed with a high-fat-sucrose diet (2K1C rats on HFS diet). Sesamin was intragastrically administered to 2K1C rats on HFS diet for eight weeks. Then, we measured the levels of serum hydrogen peroxide (H₂O₂), total antioxidant capability (T-AOC), renal malonaldehyde (MDA), total-erythrocuprein (T-SOD) and glutathione peroxidase (GSH-P(X)). The expressions of endothelial nitric oxide synthase (eNOS), nitrotyrosine and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit p47(phox) in the left and right renal cortexes were detected by Western blotting. Pathological changes in the left and right renal cortexes were observed by periodic acid-schiff staining (PAS) and Masson's staining. Treatment with sesamin (120 and 60mg/kg⁻¹·d⁻¹) in 2K1C rats on HFS diet improved renal function, corrected structural abnormalities, and attenuated renal oxidative stress. Furthermore, sesamin increased eNOS protein expression and reduced nitrotyrosine and p47phox protein expression. These results demonstrated that long-term treatment with sesamin had renoprotective effect and improved renal endothelial dysfunction via upregulation of eNOS expression and reduction of NO oxidative inactivation in both clipped and contralateral kidneys of 2K1C rats on HFS diet, and sesamin may have a favorably therapeutic value in treating chronic kidney disease in patients with hypertension and hyperlipemia.

Simultaneous determination of ten active components in 12 Chinese Piper species by HPLC

Piper is a genus that is recently valued for the treatment of central nervous system diseases. The major constituents, amides and lignans, are responsible for the antinociceptive and antidepressant activities. This study developed a RP-HPLC-UV method for the simultaneous determination of eight amides and two lignans in twelve different species of Piper. HPLC separation was accomplished on a C18 analytical column (5 μm, 250 mm × 4.6 mm, i.d.) with a gradient mobile phase consisting of acetonitrile and water at a flow rate of 1.0 ml/min. All the calibration curves showed good linear correlation coefficients (r > 0.9997) over the test ranges. The relative standard deviation of the current method was less than 2.90% for intra- and inter-day assays and the average recoveries were between 98.25% and 103.08%. The HPLC method established is appropriate for quality control purposes and allows for the differentiation of Piper species.

The mechanism underlying the synergetic hypocholesterolemic effect of sesamin and α-tocopherol in rats fed a high-cholesterol diet

Sesamin is a major lignan in sesame seed. We confirmed that ingestion of sesamin and α-tocopherol synergistically reduced the concentration of blood cholesterol in rats given a high-cholesterol diet. To elucidate the molecular mechanism behind this effect, we analyzed the gene-expression profiles in rat liver after co-ingestion of sesamin and α-tocopherol. Six-week-old male Sprague-Dawley rats were fed a 1% cholesterol diet (HC) or HC containing 0.2% sesamin, 1% α-tocopherol or sesamin + α-tocopherol for 10 days. Blood samples were collected on days 1, 3, 7, and 10 and livers were excised on day 10. The gene expressions of ATP-binding cassette, sub-family G (WHITE), members 5 (ABCG5) and 8 (ABCG8) were significantly increased, while the gene expression of apolipoprotein (Apo) A4 was significantly decreased. ABCG5 and ABCG8 form a functional heterodimer that acts as a cholesterol efflux transporter, which contributes to the excretion of cholesterol from the liver. ApoA4 controls the secretion of ApoB, which is a component of low-density-lipoprotein cholesterol. These studies indicate that the cholesterol-lowering mechanism underlying the effects of co-ingestion of sesamin and α-tocopherol might be attributable to increased biliary excretion of cholesterol and reduced ApoB secretion into the bloodstream.

Sesame oil exhibits synergistic effect with anti-diabetic medication in patients with type 2 diabetes mellitus

BACKGROUND & AIMS

Recently, studies have reported that sesame oil lowered blood pressure and improved antioxidant status in hypertensive and diabetic-hypertensive patients. The aim of this study was to evaluate the effectiveness of sesame oil with anti-diabetic (glibenclamide) medication as combination therapy in mild-to moderate diabetic patients.

METHODS

This open label study included sixty type 2 diabetes mellitus patients divided into 3 groups, receiving sesame oil (n = 18), 5 mg/day (single dose) of glibenclamide (n = 20), or their combination (n = 22). The patients were supplied with sesame oil [BNB Sesame oil(TM)] except glibenclamide group, and instructed to use approximately 35 g of oil/day/person for cooking, or salad preparation for 60 days. 12 h-fasting venous blood samples were collected at baseline (0 day) and after 60 days of the experiment for various biochemical analysis.

RESULTS

As compared with sesame oil and glibenclamide alone, combination therapy showed an improved anti-hyperglycemic effect with 36% reduction of glucose (P < 0.001 vs before treatment, P < 0.01 vs sesame oil monotherapy, P < 0.05 vs glibenclamide monotherapy) and 43% reduction of HbA(1c) (P < 0.001 vs before treatment, P < 0.01 vs sesame oil monotherapy, P < 0.05 vs glibenclamide monotherapy) at the end point. Significant reductions in the plasma TC, LDL-C and TG levels were noted in sesame oil (20%, 33.8% and 14% respectively vs before treatment) or combination therapies (22%, 38% and 15% respectively vs before treatment). Plasma HDL-C was significantly improved in sesame oil (15.7% vs before treatment) or combination therapies (17% before treatment). Significant (P < 0.001) improvement was observed in the activities of enzymatic and non-enzymatic antioxidants in patients treated with sesame oil and its combination with glibenclamide.

CONCLUSIONS

Sesame oil exhibited synergistic effect with glibenclamide and can provide a safe and effective option for the drug combination that may be very useful in clinical practice for the effective improvement of hyperglycemia.

Genotoxicity evaluation of sesamin and episesamin

Sesamin is a major lignan that is present in sesame seeds and oil. Sesamin is partially converted to its stereoisomer, episesamin, during the refining process of non-roasted sesame seed oil. We evaluated the genotoxicity of these substances through the following tests: a bacterial reverse mutation assay (Ames test), a chromosomal aberration test in cultured Chinese hamster lung cells (CHL/IU), a bone marrow micronucleus (MN) test in Crlj:CD1 (ICR) mice, and a comet assay using the liver of Sprague-Dawley (SD) rats. Episesamin showed negative results in the Ames test with and without S9 mix, in the in vitro chromosomal aberration test with and without S9 mix, and in the in vivo comet assay. Sesamin showed negative results in the Ames test with and without S9 mix. In the in vitro chromosomal aberration test, sesamin did not induce chromosomal aberrations in the absence of S9 mix, but induced structural abnormalities at cytotoxic concentrations in the presence of S9 mix. Oral administration of sesamin at doses up to 2.0g/kg did not cause a significant increase in either the percentage of micronucleated polychromatic erythrocytes in the in vivo bone marrow MN test or in the % DNA in the comet tails in the in vivo comet assay of liver cells. These findings indicate that sesamin does not damage DNA in vivo and that sesamin and episesamin have no genotoxic activity.

Sesamin inhibits bacterial formylpeptide-induced inflammatory responses in a murine air-pouch model and in THP-1 human monocytes

The reaction of human leukocytes to chemoattractants is an important component of the host immune response and also plays a crucial role in the development of inflammation. Sesamin has been shown to inhibit lipid peroxidation and regulate cytokine production. In this study, we examined the effect of sesamin on inflammatory responses elicited by the bacterial chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (fMLF) in vitro and in vivo and explored the mechanisms involved. fMLF is recognized by a human G protein-coupled receptor formyl peptide receptor (FPR) on phagocytic leukocytes. Sesamin at concentrations between 12.5 and 50 micromol/L inhibited fMLF-induced chemotaxis of human monocyte cell line THP-1 differentiated with dibutyryl cyclic AMP (P < 0.01). Similarly, sesamin inhibited FPR-transfected rat basophilic leukemia cell [epitope-tagged human FPR (ETFR) cell] migration toward fMLF (P < 0.01). In fMLF-induced inflammation in a murine air-pouch model, intraperitoneal administration of sesamin (12 mgkg(-1)d(-1) for 2 d) suppressed leukocyte infiltration into the air pouch induced by fMLF [(62.89 +/- 7.93) x 10(4) vs. (19.67 +/- 4.43) x 10(4) cells/air pouch; n = 9; P < 0.001]. Ca(2+) mobilization and mitogen-activated protein kinase extracellular signal-regulated kinase (ERK1/2) activation are involved in fMLF-induced leukocyte migration. Pretreatment of ETFR cells with sesamin inhibited fMLF-induced ERK1/2 phosphorylation in a dose-dependent manner but did not affect fMLF-induced Ca(2+) flux. Electrophoretic mobility shift assay showed that pretreatment of THP-1 cells with sesamin dose dependently inhibited fMLF-induced nuclear factor-kappaB (NF-kappaB) activation. These results suggest that sesamin inhibits leukocyte activation by fMLF through ERK1/2- and NF-kappaB-related signaling pathways and thus is a potential compound for the management of inflammatory diseases.

Sesamin improves endothelial dysfunction in renovascular hypertensive rats fed with a high-fat, high-sucrose diet

The present study was designed to evaluate the possible in vivo protective effects of sesamin on hypertension and endothelial function in two-kidney, one-clip renovascular hypertensive rats fed with a high-fat, high-sucrose diet (2K1C rats on HFS diet). Sesamin was orally administered for 8 weeks in 2K1C rats on HFS diet. Then, the serum malondialdehyde level was determined. The protein expression of endothelial nitric oxide synthase (eNOS), nitrotyrosine and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit p47(phox) in aortas was detected by Western blotting. Vasorelaxation response to acetylcholine and nitroprusside, and functional assessment of nitric oxide (NO) bioactivity were also determined in aortic rings. Sesamin treatment reduced systolic blood pressure, improved vasodilatation induced by acetylcholine and enhanced NO bioactivity in the thoracic aortas. These changes were associated with increased eNOS, decreased malondialdehyde content, and reduced nitrotyrosine and p47(phox) protein expression. All these results suggest that chronic treatment with sesamin reduces hypertension and improves endothelial dysfunction through upregulation of eNOS expression and reduction of NO oxidative inactivation in 2K1C rats on HFS diet.

Antihypertensive effects of sesamin in humans

Sesamin, one of the lignans contained in sesame, has been considered to have medicinal effects. It has been reported that sesamin suppressed the development of hypertension in rats. In this study, using a double-blind, cross-over, placebo-controlled trial, we investigated the effect of 4-wk administration of sesamin on blood pressure (BP) in mildly hypertensive humans. Twenty-five middle-aged subjects with mild hypertension were divided into two groups, matched by age and body mass index. Twelve subjects were allocated to 4-wk intake of capsules with 60 mg sesamin per day and 13 subjects to 4-wk intake of a placebo (period 1). After a 4-wk washout period, the subjects received the alternative administration for 4 wk (period 2). BP decreased with statistical significance with the administration of sesamin (systolic: 137.6+/-2.2 to 134.1+/-1.7 mmHg, p=0.044, diastolic: 87.7+/-1.3 to 85.8+/-1.0 mmHg, p=0.045), but little changed with the placebo (systolic: 135.0+/-1.8 to 135.1+/-1.7 mmHg, diastolic: 85.9+/-1.2 to 86.6+/-1.2 mmHg). In conclusion, 4-wk administration of 60 mg sesamin significantly decreased BP by an average of 3.5 mmHg systolic BP and 1.9 mmHg diastolic BP. These results suggest that sesamin has an antihypertensive effect in humans. Epidemiological studies suggested that a 2-3 mmHg decrease in BP reduces the rate of cardiovascular diseases; therefore, it is considered that BP reduction achieved by sesamin may be meaningful to prevent cardiovascular diseases.

First chemical synthesis of antioxidative metabolites of sesamin

The first chemical synthesis of two metabolites ((1R,2S,5R,6S)-6-(3,4-dihydroxyphenyl)-2-(3,4-methylenedioxyphenyl)-3,7-dioxabicyclo[3,3,0]octane (SC-1) and (1R,2S,5R,6S)-2,6-bis(3,4-dihydroxyphenyl)-3,7-dioxabicyclo[3,3,0]octane (SC-2)) of sesamin was achieved by a simple two-step approach from sesamin. The approach consists of acetoxylation of the methylenedioxy moiety(ies) with lead(IV) tetraacetate and acid hydrolysis of the resulting hemiorthoester to SC-1 and SC-2.

Nitric oxide pathway-mediated relaxant effect of aqueous sesame leaves extract (Sesamum radiatum Schum. & Thonn.) in the guinea-pig isolated aorta smooth muscle

Background

Sesamum radiatum Schum. & Thonn. (Pedaliaceae) is an annual herbaceous plant, which belongs to the family Pedaliaceae and genus Sesamum. Sesame is used in traditional medicine in Africa and Asia for many diseases treatment. Sesame plant especially the leaves, seed and oil are consumed locally as a staple food by subsistence farmers. The study analyses the relaxation induced by the aqueous extract of leaves from sesame (ESera), compared with those of acetylcholine (ACh) in the guinea-pig aortic preparations (GPAPs), in order to confirm the use in traditional medicine for cardiovascular diseases.

Methods

The longitudinal strips of aorta of animals were rapidly removed from animals. The aorta was immediately placed in a Mac Ewen solution. Experiments were performed in preparations with intact endothelium as well as in aortae where the endothelium had been removed. The preparations were suspended between two L-shaped stainless steel hooks in a 10 ml organ bath with Mac Ewen solution. The isometric contractile force of the aorta strips of guinea-pig were recorded by using a strain gauge. All both drugs caused concentration-dependent relaxations responses.

Results

The aqueous extract of leaves from sesame ESera (1 × 10^-7 – 0.1 μg/ml) caused a graded relaxation in GPAPs with intact endothelium, with a EC₅₀-value of 1 × 10^-4 μg/ml. The same effect was observed with ACh (7 × 10^-2 nM – 7 × 10^-1 μM), which caused relaxation in a concentration-dependent manner. The relaxation in response to ESera and, like that to ACh in GPAPs without endothelium, was fully abolished. Destruction of the endothelium or incubation with the nitric oxyde synthase inhibitor (L-NNA) significantly enhanced the inhibition of the relaxation response to ESera. Moreover, all concentrations induced vasoconstrictions. However, L-NNA produced a significant displacement to the right (about 65-fold) of the relaxation response to ESera. Similar results were obtained with ACh. Both diclofenac and tetra-ethyl-ammonium (TEA) pretreatment of GPAPs induced a suppression of the relaxation caused by ESera, and produced a very significant rightward shifts of the CRC (16-fold) for diclofenac and increase the Emax. In contract, the relaxation caused by ACh was not significantly affected by diclofenac or by TEA.

Conclusion

Thus, the present results indicate clearly that the nitric oxide largely contribute to the relaxation effect of Esera and of ACh in GPAPs. In addition, their contractile effects are also mediated by cyclooxygenase activation, and probably the K+ channels involvement, that confirm the use of various preparations of Esera for the treatments of cardiovascular diseases.

Dietary sesamin suppresses aortic NADPH oxidase in DOCA salt hypertensive rats

1. Dietary sesamin, a sesame lignan, is known to suppress the development of experimental hypertension in rats partly through its inhibitory effect on vascular O(2)(-) production. Therefore, in the present study, we examined whether sesamin feeding had any effect on vascular NADPH oxidase using aortas from deoxycorticosterone acetate (DOCA) salt hypertensive rats. 2. After a 5 week feeding and treatment period, aortic O(2)(-) production and NADPH oxidase activity were measured using the lucigenin assay. Reverse transcription-polymerase chain reaction was performed to analyse aortic expression of NADPH oxidase subunit (p22phox, gp91phox, Nox1 and Nox4) mRNA. 3. Sesamin feeding markedly suppressed DOCA salt-induced hypertension and significantly decreased aortic O(2)(-) production. DOCA salt treatment increased NADPH oxidase activity and elevated aortic mRNA expression of p22phox, gp91phox, Nox1 and Nox4. Sesamin feeding abolished the increase in NADPH oxidase activity and, furthermore, significantly suppressed increases in p22phox, gp91phox and Nox1 mRNA expression. 4. In conclusion, dietary sesamin prevented DOCA salt-induced increases in NADPH oxidase activity and subunit mRNA expression. These effects seem to be involved in the anti-oxidant and antihypertensive effects of sesamin.

Sesamin, a lignan of sesame, down-regulates cyclin D1 protein expression in human tumor cells

Sesamin is a major lignan constituent of sesame and possesses multiple functions such as antihypertensive, cholesterol-lowering, lipid-lowering and anticancer activities. Several groups have previously reported that sesamin induces growth inhibition in human cancer cells. However, the nature of this growth inhibitory mechanism remains unknown. The authors here report that sesamin induces growth arrest at the G1 phase in cell cycle progression in the human breast cancer cell line MCF-7. Furthermore, sesamin dephosphorylates tumor-suppressor retinoblastoma protein (RB). It is also shown that inhibition of MCF-7 cell proliferation by sesamin is correlated with down-regulated cyclin D1 protein expression, a proto-oncogene that is overexpressed in many human cancer cells. It was found that sesamin-induced down-regulation of cyclin D1 was inhibited by proteasome inhibitors, suggesting that sesamin suppresses cyclin D1 protein expression by promoting proteasome degradation of cyclin D1 protein. Sesamin down-regulates cyclin D1 protein expression in various kinds of human tumor cells, including lung cancer, transformed renal cells, immortalized keratinocyte, melanoma and osteosarcoma. Furthermore, depletion of cyclin D1 protein using small interfering RNA rendered MCF-7 cells insensitive to the growth inhibitory effects of sesamin, implicating that cyclin D1 is at least partially related to the antiproliferative effects of sesamin. Taken together, these results suggest that the ability of sesamin to down-regulate cyclin D1 protein expression through the activation of proteasome degradation could be one of the mechanisms of the antiproliferative activity of this agent.

A pilot study of open label sesame oil in hypertensive diabetics

The objective of this study was to investigate the effect of sesame oil in hypertensive diabetics medicated with atenolol (beta-blocker) and glibenclamide (sulfonylurea). This open label trial with two intervention periods comprised 22 male and 18 female patients, 45-65 years old, with mild to moderate hypertension and diabetes. Sesame oil (Idhayam Gingelly oil, V.V.V. & Sons, Virudhunagar, Tamilnadu, India) was supplied to the patients, who were instructed to use it in place of other cooking oils for 45 days. Blood pressure (BP), anthropometric measurements, plasma glucose, glycated hemoglobin (HbA1c), lipid profiles [total cholesterol, low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol, and triglycerides (TG)], lipid peroxidation [thiobarbituric acid-reactive substances (TBARS)], electrolytes (sodium, potassium, and chloride), and enzymic (superoxide dismutase, glutathione peroxidase, and catalase) and nonenzymic (vitamin C, vitamin E, beta-carotene, and reduced glutathione) antioxidants were measured at baseline and after 45 days of sesame oil substitution. The same patients were then switched over to other oils like palm or groundnut oils as their regular oils at random for another 45 days, and the investigations were carried out again at the end. Systolic and diastolic BP decreased remarkably. When oil substitution was withdrawn, BP values rose again. Body weight, body mass index, girth of waist, girth of hip, and waist:hip ratio were reduced upon substitution of sesame oil. Plasma glucose, HbA1c, TC, LDL-C, and TG were decreased. TBARS level was reduced, while the activities of enzymic and the levels of nonenzymic antioxidants were increased. Plasma sodium levels were reduced, while potassium levels were elevated. These results indicate that substitution of sesame oil as the sole edible oil has an additive effect in further lowering BP and plasma glucose in hypertensive diabetics.

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

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.

Sesamin is one of the major precursors of mammalian lignans in sesame seed (Sesamum indicum) as observed in vitro and in rats

Plant lignans occur in many foods, with flaxseed presently recognized as the richest source. Some plant lignans can be converted by intestinal microbiota to the mammalian lignans, enterodiol and enterolactone, which may have protective effects against hormone-related diseases such as breast cancer. This study determined whether plant lignans in sesame seed, particularly sesamin, could be metabolized to the mammalian lignans. The total plant lignan concentration in sesame seed (2180 micromol/100 g) was higher than that in flaxseed (820 micromol/100 g). In vitro fermentation with human fecal inoculum showed conversion of sesamin to the mammalian lignans, although at a lower rate (1.1%) compared with that of secoisolariciresinol diglucoside (57.2%). However, when fed to female Sprague-Dawley rats for 10 d, sesamin (15 mg/kg body weight) and a 10% sesame seed diet resulted in greater (P < 0.05) urinary mammalian lignan excretion (3.2 and 11.2 micromol/d, respectively), than the control (< 0.05 micromol/d). We conclude that sesame seed is a rich source of mammalian lignan precursors and sesamin is one of them. From intermediate metabolites of sesamin identified in rat urine by GC-MS, a tentative metabolic pathway of sesamin to mammalian lignans is suggested.

Sesamol induces nitric oxide release from human umbilical vein endothelial cells

Sesamol, which is derived from sesame seed lignans, is reportedly an antioxidant. Nitric oxide (NO), the most important vascular relaxing factor, is regulated in the endothelium. In addition, NO is involved in protecting endothelium and has antiatherosclerotic and antithrombotic activities. The endothelium produces NO through the regulation of both endothelial NO synthase (eNOS) expression and activity in endothelial cells. This study sought to investigate the effect of sesamol on NO released from human umbilical vein endothelial cells (HUVEC) and to examine the expression and activity of eNOS. Sesamol induced NO release from endothelial cells in a dose-dependent manner (from 1 to 10 microM), as measured 24 h after treatment; the expression of the eNOS gene at both transcription and translation levels; and NOS activity in endothelial cells. The content of cGMP was also increased by sesamol through NO signaling. The transcription of eNOS induced by sesamol was confirmed through the activation of PI-3 kinase-Akt (protein kinase B) signaling. The results demonstrate that sesamol induces NOS signaling pathways in HUVEC and suggest a role for sesamol in cardiovascular reactivity in vivo.

Sesamin ingestion regulates the transcription levels of hepatic metabolizing enzymes for alcohol and lipids in rats

BACKGROUND

Sesamin, a major lignan in sesame seeds, has multiple functions such as stimulation effect of ethanol metabolism in mice and human, and prevention of ethanol-induced fatty liver in rats. However, the mechanism has not been clarified yet.

METHODS

The changes of gene expression were investigated in rats given 250 mg/kg of sesamin (sesamin rats) or vehicle (control rats) for three days by using a DNA microarray analysis. At 4 hr after the final ingestion, the profiles of gene expression in rat livers were compared.

RESULTS

The analysis showed that 38 transcripts were up-regulated with a significant change of more than two-fold and eight transcripts were down-regulated with a significant change to less than half in the livers of sesamin rats versus control rats. The gene expression levels of the early stage enzymes of beta-oxidation including long-chain acyl-CoA synthetase, very long-chain acyl-CoA synthetase and carnitine palmitoyltransferase were not changed, however, those of the late stage enzymes of beta-oxidation including trifunctional enzyme in mitochondria, and acyl-CoA oxidase, bifunctional enzyme and 3-ketoacyl-CoA thiolase in peroxisomes, were significantly increased by sesamin ingestion. Also, in sesamin rats, the gene expression of aldehyde dehydrogenase was increased about three-fold, whereas alcohol dehydrogenase, liver catalase and CYP2E1 were not changed. Changes in the gene expression of alcohol- and aldehyde-metabolizing enzymes observed in a DNA microarray were also confirmed by a real-time PCR method.

CONCLUSIONS

These results suggested that sesamin ingestion regulated the transcription levels of hepatic metabolizing enzymes for alcohol and lipids.

Modulation of blood pressure, lipid profiles and redox status in hypertensive patients taking different edible oils

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.

Whole Sesame Seed Is as Rich a Source of Mammalian Lignan Precursors as Whole Flaxseed

The mammalian lignans enterolactone and enterodiol, which are produced by the microflora in the colon of humans and animals from precursors in foods, have been suggested to have potential anticancer effects. This study determined the production of mammalian lignans from precursors in food bars containing 25 g unground whole flaxseed (FB), sesame seed (SB), or their combination (FSB; 12.5 g each). In a randomized crossover study, healthy postmenopausal women supplemented their diets with the bars for 4 wk each separated by 4-wk washout periods, and urinary mammalian lignan excretion was measured at baseline and after 4 wk as a marker of mammalian lignan production. Results showed an increase with all treatments (65.1-81.0 mumol/day; P < 0.0001), which did not differ among treatments. Lignan excretion with the whole flaxseed was similar to results of other studies using ground flaxseed. An unidentified lignan metabolite was detected after consumption of SB and FSB but not of FB. Thus, we demonstrated for the first time that 1) precursors from unground whole flaxseed and sesame seed are converted by the bacterial flora in the colon to mammalian lignans and 2) sesame seed, alone and in combination with flaxseed, produces mammalian lignans equivalent to those obtained from flaxseed alone.