Effects of vitamin E and sesamin on hypertension and cerebral thrombogenesis in stroke-prone spontaneously hypertensive rats

Sesamin: A Promising Therapeutic Agent for Ameliorating Symptoms of Diabetes

Diabetes is a chronic metabolic disease characterized by improperly regulating proteins, carbohydrates, and lipids due to insulin deficiency or resistance. The increasing prevalence of diabetes poses a tremendous socioeconomic burden worldwide, resulting in the rise of many studies on Chinese herbal medicines to discover the most effective cure for diabetes. Sesame seeds are among these Chinese herbal medicines that were found to contain various pharmacological activities, including antioxidant and anti-inflammatory properties, lowering cholesterol, improving liver function, blood pressure and sugar lowering, regulating lipid synthesis, and anticancer activities. These medicinal benefits are attributed to sesamin, which is the main lignan found in sesame seeds and oil. In this study, Wistar rat models were induced with type 2 diabetes using streptozotocin (STZ) and nicotinamide, and the effect of sesamin on the changes in body weight, blood sugar level, glycosylated hemoglobin (HbA1c), insulin levels, and the states of the pancreas and liver of the rats were evaluated. The results indicate a reduced blood glucose level, HbA1c, TG, and ALT and AST enzymes after sesamin treatment, while increased insulin level, SOD, CAT, and GPx activities were also observed. These findings prove sesamin's efficacy in ameliorating the symptoms of diabetes through its potent pharmacological activities.

Oxidative Stress, Antioxidants and Hypertension

As a major cause of morbidity and mortality globally, hypertension remains a serious threat to global public health. Despite the availability of many antihypertensive medications, several hypertensive individuals are resistant to standard treatments, and are unable to control their blood pressure. Regulation of the renin-angiotensin-aldosterone system (RAAS) controlling blood pressure, activation of the immune system triggering inflammation and production of reactive oxygen species, leading to oxidative stress and redox-sensitive signaling, have been implicated in the pathogenesis of hypertension. Thus, besides standard antihypertensive medications, which lower arterial pressure, antioxidant medications were tested to improve antihypertensive treatment. We review and discuss the role of oxidative stress in the pathophysiology of hypertension and the potential use of antioxidants in the management of hypertension and its associated organ damage.

Improving Sesame (Sesamum indicum L.) Seed Yield through Selection under Infection of Fusarium oxysporum f. sp. sesami

Sesame (Sesamum indicum L.), the Queen of oilseeds, is infected with different pathogens, restricting its yield. Fusarium oxysporum f. sp. sesami is the most destructive disease of sesame worldwide, causing economic losses. This work aimed to develop new high-yielding strains, resistant and/or tolerant to Fusarium. Two cycles of pedigree selection were achieved under infection of Fusarium oxysporum f. sp. sesami. Two populations in the F₂ (600 plants each) were used. The selection criteria were five single traits and another three restricted by yield. The restricted selection was better in preserving variability than the single trait selection. The observed genetic gain in percentage from the mid-parent in the F₄-generation was significant for the eight selection criteria. Single trait selection proved to be an effective method for improving the selection criterion, but it caused deleterious effects on the other correlated traits in most cases. The seed yield increased by 30.67% and 20.31% from the better parent in the first and second populations, respectively. The infection% was significantly reduced by 24.04% in the first, and 9.3% in the second, population. The selection index improved seed yield, and its attributes can be recommended.

Associations of Dietary and Circulating Vitamin E Level With Metabolic Syndrome. A Meta-Analysis of Observational Studies

Objective: The associations of dietary and circulating vitamin E level with metabolic syndrome (MetS) remains conflicting. This meta-analysis of observational study was therefore employed to investigate the issue above.

Methods: The PubMed, Web of Science and Embase database were searched up to April 2021. The observational studies on the associations of dietary and circulating vitamin E level with MetS were specified. The pooled relative risk (RR) of MetS for the highest vs. lowest dietary and circulating vitamin E level, and the standard mean difference (SMD) of dietary and circulating vitamin E level for MetS vs. control subjects, were calculated.

Results: A total of 25 observational studies with 51,276 participants, were included in this meta-analysis. The overall multi-variable adjusted RR demonstrated that the dietary vitamin E level was inversely associated with MetS (RR = 0.92, 95%CI: 0.85–1.00; P = 0.044). In addition, the dietary vitamin E level in MetS was also lower than that in control subjects according to the overall combined SMD (SMD = −0.08, 95%CI: −0.14 to −0.02; P = 0.024). On the other hand, the overall multi-variable adjusted RR showed no significant relationship between the circulating vitamin E level and MetS (RR = 1.46, 95%CI: 0.85–2.48; P = 0.17). However, the circulating vitamin E level in MetS was lower than that in control subjects according to the overall combined SMD (SMD = −0.58, 95%CI: −1.04 to −0.13; P = 0.013).

Conclusions: The results of this meta-analysis suggest that the dietary vitamin E level is inversely associated with MetS. On the other hand, current evidence is still insufficient to conclude a relationship between the circulating vitamin E level and MetS. More well-designed prospective cohort studies are needed to address the issues further.

Effects of Rare Earth Elements on Blood Pressure and Their Exposure Biomarkers: Evidence from Animal Experiments

Solid fuel combustion is an important source of the release of rare earth elements (REEs) into the ambient environment, resulting in potential adverse effects on human cardiovascular health. Our study aimed to identify reliable exposure biomarkers of REE intake and their potential role in blood pressure change. A total of 24 rats were administered with 14 REE chlorides at four doses (six rats per group). Fur samples were collected both before and after administration. Blood samples were collected after 12 weeks of REE intake. The REE concentrations in rat fur and blood samples were measured by inductively coupled plasma mass spectrometry. For each week, blood pressure, as well as heart rate and pulse pressure, were measured. The linear mixed-effect model was used to analyze the relationship between REE administration dose and blood pressure change. We found that the REE concentration in fur, but not blood, samples exhibited significant dose–response relationships with administration dose. It suggested that hair samples are a more efficient matrix for indicating the exposure level of a population to REEs than blood samples. However, there was no dose–response relationships between the administration dose and blood pressure change of rats, or with heart rate and pulse pressure for the 14 REEs. We also did not find a dose–response relationship between REE administration levels and plasma concentration of 8-hydroxy-2’-deoxyguanosine, as an important DNA oxidative stress damage biomarker. In conclusion, hair samples are more suitable as a sample type to reliably assess exposure to REEs than blood samples, and REEs did not have a direct adverse effect on blood pressure in our rat model.

Sesamin prevents apoptosis and inflammation after experimental myocardial infarction by JNK and NF-κB pathways

Myocardial infarction is a devastating event, especially when reperfusion is not performed. The inflammatory response has been associated with the pathogenesis of left ventricular remodeling after myocardial infarction. This study focused on the anti-apoptotic and anti-inflammatory effects of sesamin on ligation of the left anterior descending artery in an experimental mouse model and the potential mechanism underlying the activation of JNK and NF-κB pathways. Mice with MI induced by surgical left anterior descending coronary artery ligation were treated with sesamin by gavage for 1 week. Results showed that after treatment with sesamin, MI-induced cardiac damage was alleviated significantly, indicated by the histopathological examination. The myocardial apoptosis in the border zone was dramatically reduced by sesamin, resulting from the altered expression of apoptosis factors. Moreover, treatment with sesamin also mitigated the inflammatory response, decreased expression of cytokines and the inactivation of NF-κB (nuclear factor κB) signaling. Sesamin decreased the levels of p-JNK protein, which in turn inactivated pro-apoptotic signaling events by restoring the balance between mitochondrial pro-apoptotic Bcl-2 and Bax proteins. Thus, our study suggests that sesamin could alleviate MI-induced cardiac dysfunction through decrease of myocardial apoptosis and inflammatory response.

Sesamin attenuates neurotoxicity in mouse model of ischemic brain stroke

Stroke is a severe neurological disorder characterized by the abrupt loss of blood circulation into the brain resulting into wide ranging brain and behavior abnormalities. The present study was designed to evaluate molecular mechanism by which sesamin (SES) induces neuroprotection in mouse model of ischemic stroke. The results of this study demonstrate that SES treatment (30 mg/kg bwt) significantly reduced infarction volume, lipid per-oxidation, cleaved-caspase-3 activation, and increased GSH activity following MCAO in adult male mouse. SES treatment also diminished iNOS and COX-2 protein expression, and significantly restored SOD activity and protein expression level in the ischemic cortex of the MCAO animals. Furthermore, SES treatment also significantly reduced inflammatory and oxidative stress markers including Iba1, Nox-2, Cox-2, peroxynitrite compared to placebo MCAO animals. Superoxide radical production, as studied by DHE staining method, was also significantly reduced in the ischemic cortex of SES treated compared to placebo MCAO animals. Likewise, downstream effects of superoxide free radicals i.e. MAPK/ERK and P38 activation was also significantly attenuated in SES treated compared to placebo MCAO animals. In conclusion, these results suggest that SES induces significant neuroprotection, by ameliorating many signaling pathways activated/deactivated following cerebral ischemia in adult mouse.

Protective effects of the polyphenol sesamin on allergen-induced T(H)2 responses and airway inflammation in mice

Allergic asthma is a lifelong airway condition that affects people of all ages. In recent decades, asthma prevalence continues to increase globally, with an estimated number of 250,000 annual deaths attributed to the disease. Although inhaled corticosteroids and β-adrenergic receptor agonists are the primary therapeutic avenues that effectively reduce asthma symptoms, profound side effects may occur in patients with long-term treatments. Therefore, development of new therapeutic strategies is needed as alternative or supplement to current asthma treatments. Sesamin is a natural polyphenolic compound with strong anti-oxidative effects. Several studies have reported that sesamin is effective in preventing hypertension, thrombotic tendency, and neuroinflammation. However, it is still unknown whether sesamin can reduce asthma-induced allergic inflammation and airway hyperresponsiveness (AHR). Our study has revealed that sesamin exhibited significant anti-inflammatory effects in ovalbumin (OVA)-induced murine asthma model. We found that treatments with sesamin after OVA sensitization and challenge significantly decreased expression levels of interleukin-4 (IL-4), IL-5, IL-13, and serum IgE. The numbers of total inflammatory cells and eosinophils in BALF were also reduced in the sesamin-treated animals. Histological results demonstrated that sesamin attenuated OVA-induced eosinophil infiltration, airway goblet cell hyperplasia, mucus occlusion, and MUC5AC expression in the lung tissue. Mice administered with sesamin showed limited increases in AHR compared with mice receiving vehicle after OVA challenge. OVA increased phosphorylation levels of IκB-α and nuclear expression levels of NF-κB, both of which were reversed by sesamin treatments. These data indicate that sesamin is effective in treating allergic asthma responses induced by OVA in mice.

Sesamin extends the mean lifespan of fruit flies

The present study investigated the anti-ageing activity of sesamin and its effect on gene expression of superoxide dismutase (SOD), catalase (CAT), methuselah (Mth) and Rpn11 in Drosophila melanogaster. Results demonstrated that 0.2 % sesamin in diet prolonged the mean lifespan of OR wild fruit flies by 12 %, accompanied by up-regulation of SOD1, SOD2, CAT and Rpn11. Sesamin at 0.2 % in diet also attenuated paraquat-induced neurodegeneration with up-regulation of SOD1, SOD2 and Rpn11 in OR wild fruit flies. Supplementation of 0.2 % sesamin in diet increased the survival time of OR wild type flies and Alzheimer flies Aβ42 33769 when they were challenged with paraquat. Furthermore, sesamin-induced increase in the activity and expression of antioxidant enzymes also suggests that the longevity promoting activity of sesamin are possibly due to its action as a hormetin by inducing oxidative stress response-mediated hormesis. It was concluded that sesamin extended the mean lifespan and alleviated the neurodegeneration in Drosophila melanogaster at least mediated by its interaction with genes SOD1, SOD2, CAT, and Rpn11, but not with gene Mth.

Acute and long-term hemodynamic effects of sesame oil consumption in hypertensive men

The possible effects of sesame oil on hemodynamics are unknown. The aim of the study was to investigate the acute and long-term effects of sesame oil on hemodynamic responses in hypertensive men. The authors enrolled 30 hypertensive men in a two-phase study. In the first phase, patients consumed 35 g of either sesame oil or control oil. Central and peripheral blood pressure, pulse wave velocity, augmentation index (AI), C-reactive protein, tumor necrosis factor α, malonydealdehyde, and total antioxidant capacity (TAC) were assessed at fast and 2 hours postprandially. In the second phase, patients consumed 35 g of either sesame oil or control oil daily for 2 months. The above-mentioned parameters were assessed before and following 15, 30, and 60 days of oil consumption. Sesame oil decreased central and peripheral diastolic pressures 1 hour postprandially (P=.006). Fifteen days of sesame oil intake decreased peripheral systolic blood pressure (P=.016) and heart rate-corrected AI75 (P=.017) and increased TAC (P=.007). This is the first study to demonstrate a favorable acute and long-term effect of sesame oil on hemodynamics in hypertensive men. Further research is warranted to establish the potential protective role of sesame oil.

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

BACKGROUND

It has been known that hypertension is an independent risk factor for cardiovascular disease (CVD). CVD is the major cause of morbidity and mortality in developed and developing countries. Elevation of blood pressure (BP) increases the adverse effect for cardiovascular outcomes. Prevention of increased BP plays a crucial role in a reduction of those outcomes, leading to a decrease in mortality. Therefore, the purpose of this study was to investigate the effects of dietary black sesame meal on BP and oxidative stress in individuals with prehypertension.

METHODS

Twenty-two women and eight men (aged 49.8 ± 6.6 years) with prehypertension were randomly divided into two groups, 15 subjects per group. They ingested 2.52 g black sesame meal capsules or placebo capsules each day for 4 weeks. Blood samples were obtained after overnight fasting for measurement of plasma lipid, malondialdehyde (MDA) and vitamin E levels. Anthropometry, body composition and BP were measured before and after 4-week administration of black sesame meal or a placebo.

RESULTS

The results showed that 4-week administration of black sesame meal significantly decreased systolic BP (129.3 ± 6.8 vs. 121.0 ± 9.0 mmHg, P < 0.05) and MDA level (1.8 ± 0.6 vs. 1.2 ± 0.6 μmol/L, P < 0.05), and increased vitamin E level (29.4 ± 6.0 vs. 38.2 ± 7.8 μmol/L, P < 0.01). In the black sesame meal group, the change in SBP tended to be positively related to the change in MDA (R = 0.50, P = 0.05), while the change in DBP was negatively related to the change in vitamin E (R = -0.55, P < 0.05). There were no correlations between changes in BP and oxidative stress in the control group.

CONCLUSIONS

These results suggest the possible antihypertensive effects of black sesame meal on improving antioxidant status and decreasing oxidant stress. These data may imply a beneficial effect of black sesame meal on prevention of CVD.

Alpha-tocopherol protects against memory impairment caused by L-NAME and modulates the injury marker and blood coagulant parameters

Cerebrovascular disease studies have shown similarity between humans and spontaneously hypertensive rats stroke-prone rats in the development of spontaneous stroke and transitory ischemic attacks (TIA). In addition, nitric oxide (NO) suppression by L-arginine methyl ester (L-NAME) can precipitate several vascular diseases including TIA and strokes. On the other hand, alpha-tocopherol (AT) has been associated with beneficial effects on vascular disorders. Four groups were tested to evaluate AT effects on NO inhibition: AT, control (C), AT + L-NAME, and L-NAME. During 4 weeks, all groups had their physiologic parameters evaluated and were submitted to neurological tests. After the sacrifice of the animals, total L-lactate dehydrogenase, fibrinogen levels, and platelet counts were measured. Our results demonstrated improvement in memory function and sensory-motor function of the rats treated with AT. The AT treatment also demonstrated a significant difference on the injury identifier, fibrinogen levels, and platelet count between the treated groups and the L-NAME group. In conclusion, AT reversed damaging L-NAME neurological effects and could be considered as a possible protective agent in neurological diseases.

Lowering of platelet aggregation and serum eicosanoid levels in rats fed with a diet containing coconut oil blends with rice bran oil or sesame oil

The present investigation was undertaken to study the effects of feeding a diet containing blended and interesterified fat to rats on thrombotic parameters such as platelet aggregation and eicosanoid levels in blood serum. Male Wistar rats were fed with a diet containing 10% fat from native; coconut oil (CNO), rice bran oil (RBO), sesame oil (SESO), blended; (CNO+RBO blend (B), CNO+SESO(B), or interesterified oils; CNO+RBO interesterified (I), CNO+SESO(I) for a period of 60 days. Rats given a diet containing blended oil of CNO+RBO(B) or CNO+SESO(B) showed a decrease in rate of ADP induced aggregation of platelets by 34% and 30%, respectively, compared to those fed with CNO. Aggregation induced by collagen was also reduced similarly in rats given blended or interesterified oils of CNO with RBO or SESO. Feeding interesterified oil CNO+RBO(I), and CNO+SESO(I) to rats also resulted in decrease in rate of ADP induced platelet aggregation by 37% and 34%, respectively, compared to rats fed with CNO. The prostacyclin/thromboxane ratio in serum was increased in rats fed with blended and interesterified oil compared to those fed with CNO. These results indicated that CNO when blended or interesterified with RBO or SESO exhibit antithrombotic effects as compared to the effect observed by feeding rats with CNO.

Losartan improved respiratory function and coenzyme Q content in brain mitochondria of young spontaneously hypertensive rats

Increased production of free radicals and impairment of mitochondrial function are important factors in the pathogenesis of hypertension. This study examined the impact of hypertension on mitochondrial respiratory chain function, coenzyme Q(9) (CoQ(9)), coenzyme Q(10) (CoQ(10)), and alpha-tocopherol content in brain mitochondria, and the effect of blockade of angiotensin II type 1 receptors (AT1R) in the prehypertensive period on these parameters. In addition, blood pressure, heart and brain weight to body weight ratios, and the geometry of the basilar artery supplying the brain were evaluated. In the 9th week blood pressure and heart weight/body weight ratio were significantly increased and brain weight/body weight ratio was significantly decreased in spontaneously hypertensive rats (SHR) when compared to Wistar rats (WR). The cross-sectional area of the basilar artery was increased in SHR. Glutamate-supported respiration, the rate of ATP production, and concentrations of CoQ(9), CoQ(10), and alpha-tocopherol were decreased in SHR. The succinate-supported function and cytochrome oxidase activity were not changed. The treatment of SHR with losartan (20 mg/kg/day) from 4th to 9th week of age exerted preventive effect against hypertension, heart and arterial wall hypertrophy, and brain weight/body weight decline. After the therapy, the rate of ATP production and the concentration of CoQ increased in comparison to untreated SHR. The impairment of energy production and decreased level of lipid-soluble antioxidants in brain mitochondria as well as structural alterations in the basilar artery may contribute to increased vulnerability of brain tissue in hypertension. Long-term treatment with AT1R blockers may prevent brain dysfunction in hypertension.

A survey of sesamin and composition of tocopherol variability from seeds of eleven diverse sesame (Sesamum indicum L.) genotypes using HPLC-PAD-ECD

The objective of this study was to determine the composition and content of sesamin and desmethyl tocopherols such as alpha-tocopherol (alphaT), delta-tocopherol (deltaT) and gamma-tocopherol (gammaT) in seeds of sesame (Sesamum indicum L.) for 11 genotypes conserved in the United States Department of Agriculture (USDA), Agricultural Research Service (ARS) and Plant Genetic Resources Conservation Unit (PGRCU) in Griffin, Georgia, USA. Seed accessions studied were collections from eight countries worldwide, including one landrace from Thailand and two cultivars from Texas, USA. Novel methodologies and analytical techniques described herein consisted of reverse-phase high-performance liquid chromatography (HPLC) connected in series with two detection systems specific for each analyte class. Photodiode array detection was employed for sesamin analysis and electrochemical array detection was used in the determination of tocopherols. A preliminary study was conducted to assess sesamin levels in 2003 and tocopherol levels in 2004 from sesame seed samples conserved at the USDA, ARS and PGRCU. In 2005, sesame seed samples were grown, harvested and evaluated for sesamin as well as tocopherol levels. The overall results (n = 3) showed that sesamin, alphaT, deltaT and gammaT levels were 0.67-6.35 mg/g, 0.034-0.175 microg/g, 0.44-3.05 microg/g and 56.9-99.3 microg/g respectively, indicating that the sesame seed accessions contained higher levels of sesamin and gammaT compared with alphaT and deltaT. Statistical analysis was conducted and significant differences were observed among the 11 different sesame genotypes. This suggests that genetic, environmental and geographical factors influence sesamin and desmethyl tocopherol content.

Effect of chlorella and its fractions on blood pressure, cerebral stroke lesions, and life-span in stroke-prone spontaneously hypertensive rats

Effects of Chlorella regularis (dried cell powder)--cultured axenically under heterotrophic conditions, and provided as a dietary supplement--and its fractions on the blood pressure, cerebral stroke lesions, and life-span of stroke-prone spontaneously hypertensive rats (SHRSP/Izm) were investigated. When SHRSP were fed on diets with supplemented Chlorella to a commercial diet (Funabashi SP), elevation of blood pressure was significantly lower in the Chlorella groups than in the control group. At 21 wk of feeding, serum total cholesterol was significantly lower in the Chlorella groups than in the control group. Histopathological examination revealed cerebral vascular accidents in the brains of the control group, but those of Chlorella groups showed apparently low incidence compared to the control group. The average life-span of the Chlorella groups were significantly longer than that of the control group (p < 0.001). Chlorella powder was fractionated into three fractions, lipid-soluble, hot water-soluble, and residual fractions. The diets supplemented with lipid or residual fractions equivalent to 10% Chlorella significantly suppressed elevation of blood pressure in SHRSP, and then decreased the incidence rate of cerebral vessel lesions compared to the control group. Chemical analysis revealed that the lipid fraction contained large quantities of antioxidants, including carotenoids (especially lutein) and others, and phospholipids involved in aorta collagen and elastin metabolism; the residual fraction contained high concentrations of arginine, enhancing the function of blood vessels. The control diet contained only a little these substances. These experimental results suggest that the beneficial effect of Chlorella on SHRSP is caused by the synergistic action of several ingredients of Chlorella, which play a role in sustention of a vascular function of rats.