Sesamin, a sesame lignan, decreases fatty acid synthesis in rat liver accompanying the down-regulation of sterol regulatory element binding protein-1

Sesamin ameliorates lipotoxicity and lipid accumulation through the activation of the estrogen receptor alpha signaling pathway

Nonalcoholic fatty liver disease (NAFLD) has been linked to fat accumulation in the liver and lipid metabolism imbalance. Sesamin, a lignan commonly found in sesame seed oil, possesses antioxidant, anti-inflammatory, and anticancer properties. However, the precise mechanisms by which sesamin prevents hepatic steatosis are not well understood. This study aimed to explore the molecular mechanisms by which sesamin may improve lipid metabolism dysregulation. A in vitro hepatic steatosis model was established by exposing HepG2 cells to palmitate sodium. The results showed that sesamin effectively mitigated lipotoxicity and reduced reactive oxygen species production. Additionally, sesamin suppressed lipid accumulation by regulating key factors involved in lipogenesis and lipolysis, such as fatty acid synthase (FASN), sterol regulatory element-binding protein 1c (SREBP-1c), forkhead box protein O-1, and adipose triglyceride lipase. Molecular docking results indicated that sesamin could bind to estrogen receptor α (ERα) and reduce FASN and SREBP-1c expression via the Ca2+/calmodulin-dependent protein kinase kinase β (CaMKKβ)/AMP-activated protein kinase (AMPK) signaling pathway. Sesamin attenuated palmitate-induced lipotoxicity and regulated hepatic lipid metabolism in HepG2 cells by activating the ERα/CaMKKβ/AMPK signaling pathway. These findings suggest that sesamin can improve lipid metabolism disorders and is a promising candidate for treating hepatic steatosis.

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.

Analysis of genetic diversity and selection signals in Chaling cattle of southern China using whole-genome scan

China has diversified resources of indigenous cattle, which are classified into Northern, Central, and Southern groups according to their geographical distribution. Chaling cattle belong to Southern group. This breed is famous for the production of good quality meat with elite meat grades. To analyze the genetic diversity of Chaling cattle, 20 samples were sequenced using whole-genome resequencing technology, along with 138 published whole-genome sequencing data of Indian indicine cattle, Chinese indicine cattle, East Asian taurine cattle, Eurasian taurine cattle, and European taurine cattle as control. It was found that Chaling cattle originated from Chinese indicine cattle. The genetic diversity of Chaling cattle is higher than that of Indian indicine cattle, East Asian taurine cattle, Eurasian taurine cattle, and European taurine cattle, but lower than that of Chinese indicine cattle and Xiangxi cattle. Annotating the selection signals obtained by composite likelihood ratio, θπ, F_ST , π-ratio, and XP-EHH methods, several genes associated with immunity, heat tolerance, reproduction, growth, and meat quality showed strong selection signals. In general, this study provides a theoretical basis for analyzing the genetic mechanism of Chaling cattle with excellent adaptability, rough feeding tolerance, good immune performance, and good meat quality. This work lays a foundation for genetic breeding of Chaling cattle in future.

Comparative effects of sesame lignans (sesamin, sesamolin, and sesamol) on oxidative stress and lipid metabolism in steatosis HepG2 cells

Non-alcoholic fatty liver disease (NAFLD) can be attributed to the imbalance between lipogenesis and lipidolysis in the liver. Sesame lignans (sesamin, sesamolin, and sesamol) are unique bioactive compounds responsible for the nutritional function of sesame oils. However, the preventive effects of three lignans on oxidative stress and lipid metabolism in steatosis HepG2 cells have not been compared. In this study, we investigated the role of sesamin, sesamolin, and sesamol on hepatic lipid accumulation and explored the underlying mechanism via a well-established cell model. The results showed that 3 μg/ml of lignans could decrease the TG/TC contents and alleviate cellular oxidative stress, with an order of the lipid-lowering effect as sesamol > sesamin > sesamolin. The lignan-activated AMPK and PPAR signaling pathways enhanced gene and protein expressions related to fatty acid oxidation, cholesterol efflux, and catabolism. Meanwhile, treatment of the steatosis HepG2 cells with sesamin, sesamolin, and sesamol reduced lipid synthesis and cholesterol uptake, thus lowering intracellular lipogenesis in the process of NAFLD. Our data suggested that sesame lignans can attenuate oxidative stress and regulate lipid metabolism in liver cells, which may be potential therapeutic agents for treating the NAFLD. PRACTICAL APPLICATIONS: The present work demonstrated that sesame lignans can be used for dietary supplements or functional additives with excellent lipid-lowering effects. Furthermore, this study supplied potential molecular mechanisms involved in NAFLD treatment process, and also provided nutritional guidelines for sesame oil evaluation and selection.

Sesame Oil Ameliorates Alanine Aminotransferase, Aspartate Aminotransferase, and Fatty Liver Grade in Women with Nonalcoholic Fatty Liver Disease Undergoing Low-Calorie Diet: A Randomized Double-Blind Controlled Trial

Background

The type and amount of dietary fats play an important role in fat accumulation in the liver. Sesame oil (SO) is a good source of monounsaturated acids (MUFAs) and polyunsaturated fatty acids (PUFAs).

Objective

This trial aimed at examining the effect of SO consumption on the levels of liver enzymes and the severity of fatty liver in women with nonalcoholic fatty liver disease (NAFLD) undergoing a weight loss diet.

Methods

This randomized, double-blind, controlled trial was carried out on 60 women with NAFLD. Subjects were randomly assigned to the SO group (n = 30) and sunflower oil (SFO) group (n = 30), each person consuming 30 grams of oil per day for 12 weeks. All the participants received a hypocaloric diet (-500 kcal/day) during the study. Fatty liver grade and liver enzymes were assessed at pre- and postintervention phases.

Results

53 patients completed the study. Significant reductions in body weight, body mass index (BMI), waist circumference (WC), and fatty liver grade were observed in both groups (P < 0.05). Following SO, significant decreases in serum aspartate and alanine aminotransferases (AST and ALT) were observed. After adjusting for confounders, ALT, AST, and fatty liver grade of the SO group were significantly reduced compared to the SFO group (P < 0.05). However, the changes in serum alkaline phosphatase (ALP) were not significant (P > 0.05).

Conclusions

The desired effects of weight loss were reinforced by the consumption of SO through improving fatty liver severity and serum ALT and AST levels in NAFLD patients. Moreover, low-calorie diets may lead to favorable outcomes for NAFLD patients through mitigation of obesity and fatty liver grade.

The Effects of Sesamin Supplementation on Obesity, Blood Pressure, and Lipid Profile: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

AIMS

Sesamin, the main lignin constituent of sesame, plays a pivotal role in regulating physical state. Some studies have evidenced that the supplementation of sesamin may decrease cardiovascular disease risk. The goal of this systematic review was to summarize evidence of the effects of sesamin supplementation on obesity, blood pressure, and lipid profile in humans by performing a meta-analysis of randomized controlled trials.

DATA SYNTHESIS

Five databases (PubMed, Cochrane Library, EMBASE, Web of Science, and Scopus) were searched electronically from inception to July 2021 to identify randomized controlled trials that assessed the impact of sesamin on obesity, blood pressure, and lipid profile. Weighted mean difference (WMD) and standard deviation (SD) were used to present the major outcomes.

CONCLUSIONS

Seven trials (n = 212 participants) were included in the overall analysis. Results showed that sesamin supplementation caused a great reduction in TC (WMD: -10.893 mg/dl, 95% CI: -19.745 to -2.041, p = 0.016), LDL-c (WMD: -8.429 mg/dl, 95% CI: -16.086 to -0.771, p = 0.031), and SBP (WMD: -3.662 mmHg, 95% CI: -6.220 to -1.105, p = 0.005), whereas it had no effect on HDL-c, TG, DBP, or weight. Subgroup analysis showed that duration, parallel design, and unhealthy status can affect TC, LDL-c, and SBP evidently. We did not discover a strong link between indicators' changes and duration of supplementation. Sesamin can be used as an obtainable dietary supplement to improve blood pressure and blood lipids, and further as a health product to prevent cardiovascular diseases.

A Review on Antidiabetic Activity of Centaurea spp.: A New Approach for Developing Herbal Remedies

Objective

Diabetes mellitus (DM) is a long-life metabolic disorder, characterized by high blood glucose levels. The hyperglycemic condition generally leads to irreversible nerve injury and vascular damage. Among different types of diabetes, type 2 is more common and has spread all over the world. Although various therapeutic approaches have been developed to control type 2 DM, regulating blood glucose levels has still remained a controversial challenge for patients. Also, most prescription drugs cause different side effects, such as gastrointestinal disorders. Thus, developing novel and efficient antidiabetic agents possessing fewer adverse effects is in high demand.

Method

The literature was comprehensively surveyed via search engines such as Google Scholar, PubMed, and Scopus using appropriate keywords.

Results

Medicinal plants, both extracts and isolated active components, have played a significant role in controlling the blood glucose levels. Good-to-excellent results documented in the literature have made them a precious origin for developing and designing drugs and supplements against DM. Centaurea spp. have been traditionally used for controlling high blood glucose levels. Also, the antidiabetic properties of different species of Centaurea have been confirmed in recent studies through in vitro assays as well as in vivo experiments.

Conclusion

Potent results encouraged us to review their efficacy to open a new horizon for development of herbal antidiabetic agents.

Clinical evidence of dietary supplementation with sesame on cardiovascular risk factors: An updated meta-analysis of randomized controlled trials

The present analysis was to summarize the evidence of the effects of sesame and its derivatives supplementation on cardiovascular disease (CVD) risk factors by performing a meta-analysis of randomized controlled trials (RCTs). Electronic databases were searched from their inception to July 2020. Two investigators independently assessed articles for inclusion, extracted data, and statistical analysis. The quality of included articles was assessed according to the Cochrane risk of bias tool. Major outcomes were synthesized using a random effect model and presented as weighted mean difference and 95% confidence interval. Heterogeneity, subgroup analyses, sensitivity analysis, meta-regression, and publication bias were also conducted. The GRADE approach was used to evaluate the quality of evidence. Overall, 16 trials involving 908 participants were included for statistical pooling. Compared with the control group, sesame intake significantly decreased the levels of total cholesterol, triglycerides, systolic blood pressure, diastolic blood pressure, body weight, body mass index, hip circumference, and waist circumference (P < 0.05). These results were stable in sensitivity analysis, and no significant publication bias was detected. Our findings provided evidence that sesame consumption may reduce the risk of CVD by improving blood lipids, blood pressure, and body weight management. Further large-scale, well-designed RCTs are required to confirm these results.

Nutraceutical Properties of Polyphenols against Liver Diseases

Current food tendencies, suboptimal dietary habits and a sedentary lifestyle are spreading metabolic disorders worldwide. Consequently, the prevalence of liver pathologies is increasing, as it is the main metabolic organ in the body. Chronic liver diseases, with non-alcoholic fatty liver disease (NAFLD) as the main cause, have an alarming prevalence of around 25% worldwide. Otherwise, the consumption of certain drugs leads to an acute liver failure (ALF), with drug-induced liver injury (DILI) as its main cause, or alcoholic liver disease (ALD). Although programs carried out by authorities are focused on improving dietary habits and lifestyle, the long-term compliance of the patient makes them difficult to follow. Thus, the supplementation with certain substances may represent a more easy-to-follow approach for patients. In this context, the consumption of polyphenol-rich food represents an attractive alternative as these compounds have been characterized to be effective in ameliorating liver pathologies. Despite of their structural diversity, certain similar characteristics allow to classify polyphenols in 5 groups: stilbenes, flavonoids, phenolic acids, lignans and curcuminoids. Herein, we have identified the most relevant compounds in each group and characterized their main sources. By this, authorities should encourage the consumption of polyphenol-rich products, as most of them are available in quotidian life, which might reduce the socioeconomical burden of liver diseases.

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.

Lignans' Potential in Pre and Post-onset Type 2 Diabetes Management

INTRODUCTION

Type 2 Diabetes (T2D) cases continue to rise dramatically despite efforts to get people to exercise and eat with a view to health and combatting the cluster of 7 issues (central obesity (elevated waist circumference), hyperglycaemia, hypertension, dyslipidemia, pro-thrombotic state, increased oxidation (including Low-density Lipoprotein (LDL)) and the pro-inflammatory state associated with pre- and post-onset T2D.

BACKGROUND

There are numerous medications available to deal with these seven major issues. However, each medication currently available manages a maximum of two cluster members at a time. Consequently, polypharmacy is frequently required to manage the cluster of seven. Polypharmacy brings with it high financial costs for numerous medications, the risk of poor compliance (particularly so in older patients), side effects and drug interactions. Thus, there is a search for new agents that reduce the high costs and risks of polypharmacy while at the same time combatting three or more of the cluster of seven. There is very limited evidence to suggest that one or more lignans may efficaciously and safely, in the short and long term, manage at least three of the cluster of seven, pre- and post-T2D onset, thus reducing polypharmacy. However, multi-centre, large clinical trials are required before any definitive conclusions about these lignans can be reached regarding their safe and efficacious polypharmacy reduction potential, both long and short-term, in pre and post-onset T2D management.

CONCLUSION

It is concluded that some lignans appear to have the potential to manage at least three members of the cluster of seven in pre- or post-T2D onset and hence reduce polypharmacy but much more investigation is required to confirm if such is the case. At the moment, there is not enough evidence that any of the lignans will, in the long or short term, safely and efficaciously manage the cluster of seven via polypharmacy reduction.

Flaxseed Lignans Enhance the Cytotoxicity of Chemotherapeutic Agents against Breast Cancer Cell Lines MDA-MB-231 and SKBR3

Systemic cytotoxic chemotherapy remains the mainstay of metastatic breast cancer; however, prognosis and overall survival is unfavorable due to inadequate treatment response and/or unacceptable toxicity. Natural compounds and their active metabolites receive increasing attention as possible adjuvant therapy with cancer chemotherapeutics to improve treatment response, survival rates, and quality of life of breast cancer patients. This study investigated the combination of flaxseed lignans (Secoisolariciresinol and Enterolactone) with classic chemotherapeutic agents (Docetaxel, Doxorubicin, and Carboplatin) with different mechanisms of action to determine whether flaxseed lignans could enhance the cytotoxic effect of such drugs in the metastatic breast cancer cell lines, SKBR3 and MDA-MB-231. The experimental data suggests that flaxseed lignans significantly enhanced the ability of chemotherapeutic agents to cause cytotoxicity in SKBR3 and MDA-MB-231 breast cancer cells. A three compound combination study found that enterolactone and metformin together in combination with relatively low concentrations of chemotherapeutic drugs were able to significantly decrease cancer cell viability, compared to low concentrations of the individual chemotherapeutic drug alone. Our in vitro evaluation suggests a future direction in improving chemotherapeutic efficacy in breast cancer by adjuvant therapy with the flaxseed lignans.

Anti-inflammatory and Antioxidant Effects of Sesame Oil on Atherosclerosis: A Descriptive Literature Review

Sesame oil (SO) is a supplement that has been known to have anti-inflammatory and antioxidant properties, which makes it effective for reducing atherosclerosis and the risk of cardiovascular disease. Due to the side effects of statins, the current recommended treatment for atherosclerosis and cardiovascular diseases, the idea of using dietary and nutritional supplementation has been explored. The benefits of a dietary health regime have piqued curiosity because many different cultures have reaped health benefits through the ingredients in their cooking with negligible side effects. The purpose of this literary review is to provide a broad overview of the potential benefits and risks of SO on the development of atherosclerosis and its direction toward human clinical use. Current in vivo and in vitro research has shed light on the effects of SO and its research has shown that SO can decrease low-density lipoprotein (LDL) levels while maintaining high-density lipoprotein (HDL) levels. Current limitations in recent studies include no standardized doses of SO given to subjects and unknown specific mechanisms of the different components of SO. Future studies should explore possible synergistic and adverse effects of SO when combined with current recommended pharmaceutical therapies and other adjunct treatments.

Sesamin extends lifespan through pathways related to dietary restriction in Caenorhabditis elegans

PURPOSE

Sesamin, a polyphenolic compound found in sesame seeds, has been reported to exert a variety of beneficial health effects. We have previously reported that sesamin increases the lifespan of Caenorhabditis elegans. In this study, we investigated the molecular mechanisms underlying the longevity effect of sesamin in C. elegans.

METHODS

Starting from three days of age, Caenorhabditis elegans animals were fed a standard diet alone or supplemented with sesamin. A C. elegans genome array was used to perform a comprehensive expression analysis. Genes that showed differential expression were validated using real-time PCR. Mutant or RNAi-treated animals were fed sesamin, and the lifespan was determined to identify the genes involved in the longevity effects of sesamin.

RESULTS

The microarray analysis revealed that endoplasmic reticulum unfolded protein response-related genes, which have been reported to show decreased expression under conditions of SIR-2.1/Sirtuin 1 (SIRT1) overexpression, were downregulated in animals supplemented with sesamin. Sesamin failed to extend the lifespan of sir-2.1 knockdown animals and of sir-2.1 loss-of-function mutants. Sesamin was also ineffective in bec-1 RNAi-treated animals; bec-1 is a key regulator of autophagy, and is necessary for longevity induced by sir-2.1 overexpression. Furthermore, the heterozygotic mutation of daf-15, which encodes the target of rapamycin (TOR)-binding partner Raptor, abolished lifespan extension by sesamin. Moreover, sesamin did not prolong the lifespan of loss-of-function mutants of aak-2, which encodes the AMP-activated protein kinase (AMPK).

CONCLUSIONS

Sesamin extends the lifespan of C. elegans through several dietary restriction-related signaling pathways, including processes requiring SIRT1, TOR, and AMPK.

A Blend of Sesame and Rice Bran Oils Lowers Hyperglycemia and Improves the Lipids

BACKGROUND

Considering the health benefits of sesame oil and rice bran oil, the study was conducted to determine the extent to which the daily use of this blend of oils controls hyperglycemia and improves the lipid profile.

METHODS

In this 8-week open-label randomized dietary intervention study, 300 type 2 diabetes mellitus patients and 100 normoglycemic subjects were grouped as 1) normoglycemic subjects (n = 100) treated with sesame oil blend Vivo (Adani Wilmar, Ahmedabad, Gujarat, India), 2) type 2 diabetes mellitus patients treated with sesame oil blend (n = 100), 3) type 2 diabetes mellitus patients treated with glibenclamide (n = 100; 5 mg/d), and 4) type 2 diabetes mellitus patients treated in combination of glibenclamide (5 mg/d) and sesame oil blend (n = 100). Twelve-hour fasting blood glucose, glycated hemoglobin (HbA1c), and lipid profile followed by postprandial blood glucose were measured at baseline. Sesame oil blend was supplied to the respective groups, who were instructed to use as cooking oil for 8 weeks. Fasting and postprandial blood glucose was measured at week 4 and week 8, while HbA1c and lipid profile were measured at week 8.

RESULTS

At week 4 and week 8, type 2 diabetes mellitus patients treated with sesame oil blend or glibenclamide or combination of glibenclamide and sesame oil blend showed significant reduction of fasting and postprandial blood glucose (P <.001). HbA1c, total cholesterol, triglycerides, low-density lipoprotein cholesterol, and non-high-density lipoprotein cholesterol were significantly reduced (P <.001), while high-density lipoprotein cholesterol was significantly increased at week 8 (P <.001) in type 2 diabetes mellitus patients treated with the sesame oil blend or combination of glibenclamide and sesame oil blend; whereas glibenclamide-alone-treated type 2 diabetes mellitus patients showed a significant reduction of HbA1c (P <.001) only.

CONCLUSIONS

A novel blend of 20% cold-pressed unrefined sesame oil and 80% physically refined rice bran oil as cooking oil, lowered hyperglycemia and improved the lipid profile in type 2 diabetes mellitus patients.

Sesamin Ameliorates High-Fat Diet-Induced Dyslipidemia and Kidney Injury by Reducing Oxidative Stress

The study explored the protective effect of sesamin against lipid-induced renal injury and hyperlipidemia in a rat model. An animal model of hyperlipidemia was established in Sprague-Dawley rats. Fifty-five adult Sprague-Dawley rats were divided into five groups. The control group was fed a standard diet, while the other four groups were fed a high-fat diet for 5 weeks to induce hyperlipidemia. Three groups received oral sesamin in doses of 40, 80, or 160 mg/(kg·day). Seven weeks later, the blood lipids, renal function, antioxidant enzyme activities, and hyperoxide levels in kidney tissues were measured. The renal pathological changes and expression levels of collagen type IV (Col-IV) and α-smooth muscle actin (α-SMA) were analyzed. The administration of sesamin improved the serum total cholesterol, triglyceride, low-density lipoprotein cholesterol, apolipoprotein-B, oxidized-low-density lipoprotein, and serum creatinine levels in hyperlipidemic rats, while it increased the high-density lipoprotein cholesterol and apolipoprotein-A levels. Sesamin reduced the excretion of 24-h urinary protein and urinary albumin and downregulated α-SMA and Col-IV expression. Moreover, sesamin ameliorated the superoxide dismutase activity and reduced malondialdehyde levels in kidney tissue. Sesamin could mediate lipid metabolism and ameliorate renal injury caused by lipid metabolism disorders in a rat model of hyperlipidemia.

Fucoidan improves serum lipid levels and atherosclerosis through hepatic SREBP-2-mediated regulation

Hyperlipidemia is associated with increased risk of the development of cardiovascular diseases. Although a great deal of attention has been paid to the hypolipidemic activity of fucoidan, complex polysaccharides from brown seaweeds, the underlying mechanism is still unclear. This study was performed to investigate whether and how fucoidan has lipid-lowering potential in poloxamer-407 (P407)-induced hyperlipidemic mice. Fucoidan treatment 2 h after acute administration of P407 in these mice significantly reduced serum total cholesterol, triglycerides, and LDL cholesterol levels, but increased the levels of HDL cholesterol. In HepG2 hepatocytes and the liver, fucoidan decreased the expression of FAS and ACC mRNA with no or only a moderate inhibitory effect on SREBP-1c mRNA expression. Furthermore, fucoidan attenuated the hepatic expression of mature SREBP-2 protein with a subsequent decrease in hepatic HMG-CoA reductase mRNA expression and an increase in hepatic LDL receptor mRNA expression. In addition, atherosclerotic lesions in the aorta of chronically P407-treated mice were also reduced by fucoidan. These findings indicate that fucoidan improves serum lipid levels by regulating the expression of key enzymes of cholesterol and triglyceride syntheses in the liver through modulation of SREBP-2.

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 prevents decline in exercise capacity and impairment of skeletal muscle mitochondrial function in mice with high-fat diet-induced diabetes

New Findings

What is the central question of this study?

Our aim was to examine whether sesamin can prevent a decline in exercise capacity in high‐fat diet‐induced diabetic mice. Our hypothesis was that maintenance of mitochondrial function and attenuation of oxidative stress in the skeletal muscle would contribute to this result.

What is the main finding and its importance?

The new findings are that sesamin prevents the diabetes‐induced decrease in exercise capacity and impairment of mitochondrial function through the inhibition of NAD(P)H oxidase‐dependent oxidative stress in the skeletal muscle. Sesamin may be useful as a novel agent for the treatment of diabetes mellitus.

Abstract

We previously reported that exercise capacity and skeletal muscle mitochondrial function in diabetic mice were impaired, in association with the activation of NAD(P)H oxidase. It has been reported that sesamin inhibits NAD(P)H oxidase‐induced superoxide production. Therefore, we examined whether the antioxidant sesamin could prevent a decline in exercise capacity in mice with high‐fat diet (HFD)‐induced diabetes. C57BL/6J mice were fed a normal diet (ND) or HFD, then treated or not with sesamin (0.2%) to yield the following four groups: ND, ND+Sesamin, HFD and HFD+Sesamin (n = 10 each). After 8 weeks, body weight, fat weight, blood glucose, insulin, triglyceride, total cholesterol and fatty acid were significantly increased in HFD compared with ND mice. Sesamin prevented the increases in blood insulin and lipid levels in HFD‐fed mice, but did not affect the plasma glucose. Exercise capacity determined by treadmill tests was significantly reduced in HFD mice, but almost completely recovered in HFD+Sesamin mice. Citrate synthase activity was significantly decreased in the skeletal muscle of HFD mice, and these decreases were also inhibited by sesamin. Superoxide anion and NAD(P)H oxidase activity were significantly increased in HFD mice compared with the ND mice and were ameliorated by sesamin. Sesamin prevented the decline in exercise capacity in HFD‐induced diabetic mice via maintenance of mitochondrial function, fat oxidation and attenuation of oxidative stress in the skeletal muscle. Our data suggest that sesamin may be useful as a novel agent for the treatment of diabetes mellitus.

The relationship of antioxidant components and antioxidant activity of sesame seed oil

Although sesame seed oil contains high levels of unsaturated fatty acids and even a small amount of free fatty acids in its unrefined flavored form, it shows markedly greater stability than other dietary vegetable oils. The good stability of sesame seed oil against autoxidation has been ascribed not only to its inherent lignans and tocopherols but also to browning reaction products generated when sesame seeds are roasted. Also, there is a strong synergistic effect among these components. The lignans in sesame seed oil can be categorized into two types, i.e. inherent lignans (sesamin, sesamolin) and lignans mainly formed during the oil production process (sesamol, sesamolinol, etc.). The most abundant tocopherol in sesame seed oil is γ-tocopherol. This article reviews the antioxidant activities of lignans and tocopherols as well as the browning reaction and its products in sesame seed and/or its oil. It is concluded that the composition and structure of browning reaction products and their impacts on sesame ingredients need to be further studied to better explain the remaining mysteries of sesame oil.

Cholesterol-lowering activity of sesamin is associated with down-regulation on genes of sterol transporters involved in cholesterol absorption

Sesame seed is rich in sesamin. The present study was to (i) investigate the plasma cholesterol-lowering activity of dietary sesamin and (ii) examine the interaction of dietary sesamin with the gene expression of sterol transporters, enzymes, receptors, and proteins involved in cholesterol metabolism. Thirty hamsters were divided into three groups fed the control diet (CON) or one of two experimental diets containing 0.2% (SL) and 0.5% (SH) sesamin, respectively, for 6 weeks. Plasma total cholesterol (TC) levels in hamsters given the CON, SL, and SH diets were 6.62 ± 0.40, 5.32 ± 0.40, and 5.00 ± 0.44 mmol/L, respectively, indicating dietary sesamin could reduce plasma TC in a dose-dependent manner. Similarly, the excretion of total fecal neutral sterols was dose-dependently increased with the amounts of sesamin in diets (CON, 2.65 ± 0.57; SL, 4.30 ± 0.65; and SH, 5.84 ± 1.27 μmol/day). Addition of sesamin into diets was associated with down-regulation of mRNA of intestinal Niemann-Pick C1 like 1 protein (NPC1L1), acyl-CoA:cholesterol acyltransferase 2 (ACAT2), microsomal triacylglycerol transport protein (MTP), and ATP-binding cassette transporters subfamily G members 5 and 8 (ABCG5 and ABCG8). Results also showed that dietary sesamin could up-regulate hepatic cholesterol-7α-hydroxylase (CYP7A1), whereas it down-regulated hepatic 3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) reductase and liver X receptor alpha (LXRα). It was concluded that the cholesterol-lowering activity of sesamin was mediated by promoting the fecal excretion of sterols and modulating the genes involved in cholesterol absorption and metabolism.

Effects of quercetin derivatives from mulberry leaves: Improved gene expression related hepatic lipid and glucose metabolism in short-term high-fat fed mice

BACKGROUND/OBJECTIVES

Mulberry leaves contain quercetin derivatives, which have the effects of reducing obesity and improving lipid and glucose metabolism in mice with obesity. It is not clear whether or not mulberry leaves can directly affect metabolic disorders, in the presence of obesity, because of the interaction between obesity and metabolic disorders. The aim of the current study was to assess the direct action of quercetin derivatives on metabolic disorders in non-obese conditions in short-term high-fat diet fed mice.

MATERIALS/METHODS

C57BL/6N mice were fed a high-fat diet, supplemented with either 0% (control), 1%, or 3% mulberry leaf powder (Mul) or 1% catechin powder for five days. Anthropometric parameters and blood biochemistry were determined, and hepatic gene expression associated with lipid and glucose metabolism was analyzed.

RESULTS

Body and white fat weights did not differ among the four groups. Plasma triglycerides, total cholesterol, and free fatty acids in the 1%, 3% Mul and catechin groups did not differ significantly from those of the controls, however, plasma glucose and 8-isoprostane levels were significantly reduced. Liver gene expression of gp91phox, a main component of NADPH oxidase, was significantly down-regulated, and PPAR-α, related to β-oxidation, was significantly up-regulated. FAS and GPAT, involved in lipid metabolism, were significantly down-regulated, and Ehhadh was significantly up-regulated. Glucose-metabolism related genes, L-PK and G6Pase, were significantly down-regulated, while GK was significantly up-regulated in the two Mul groups compared to the control group.

CONCLUSIONS

Our results suggest that the Mul quercetin derivatives can directly improve lipid and glucose metabolism by reducing oxidative stress and enhancing β-oxidation. The 1% Mul and 1% catechin groups had similar levels of polyphenol compound intake (0.4 × 10^-5vs 0.4 × 10^-5 mole/5 days) and exhibited similar effects, but neither showed dose-dependent effects on lipid and glucose metabolism or oxidative stress.

Sesamin suppresses macrophage-derived chemokine expression in human monocytes via epigenetic regulation

BACKGROUND

Chemokines play important roles in the pathogenesis of asthmatic inflammation. Sesamin, a class of phytoestrogen isolated from sesame seed Sesamum indicum, is recently regarded as an anti-inflammatory agent. However, the effects of sesamin on asthma-related chemokines are unknown. To this end, we investigated the effects of sesamin on the expression interferon-γ-inducible protein-10 (IP-10/CXCL10), macrophage-derived chemokine (MDC/CCL22), growth-related oncogene-α (GRO-α/CXCL1) and tumor necrosis factor (TNF)-α in human monocytes.

METHODS

Cells were pretreated with sesamin before lipopolysaccharide (LPS) stimulation. IP-10, MDC, GRO-α and TNF-α were measured by ELISA. Involved receptors and intracellular signaling were investigated by receptor antagonists, pathway inhibitors, western blotting and chromatin immunoprecipitation.

RESULTS

Sesamin suppressed LPS-induced MDC in THP-1 and human primary monocytes. Sesamin suppressed LPS-induced IP-10 in THP-1 cells, but not human primary monocytes. Sesamin had no effects on LPS-induced GRO-α and TNF-α expression in THP-1 and human primary monocytes. The suppressive effect of sesamin on MDC was reversed by the estrogen receptor (ER) and peroxisomal proliferator-activated receptor (PPAR)-α antagonists. Sesamin suppressed LPS-induced phosphorylation of mitogen-activated protein kinase (MAPK)-p38 and nuclear factor kappa B (NFκB)-p65. Sesamin suppressed histone H3/H4 acetylation in the MDC promoter region.

CONCLUSION

Sesamin suppressed LPS-induced MDC expression via the ER, the PPAR-α, the MAPK-p38 pathway, the NFκB-p65 pathway and the epigenetic regulation. Sesamin may have therapeutic potential in preventing and treating asthma.

Combined effect of sesamin and soybean phospholipid on hepatic fatty acid metabolism in rats

We studied the combined effect of sesamin (1:1 mixture of sesamin and episesamine) and soybean phospholipid on lipid metabolism in rats. Male rats were fed diets supplemented with 0 or 2 g/kg sesamin, and containing 0 or 50 g/kg soybean phospholipid, for 19 days. Sesamin and soybean phospholipid decreased serum triacylglycerol concentrations and the combination of these compounds further decreased the parameter in an additive fashion. Soybean phospholipid but not sesamin reduced the hepatic concentration of triacylglycerol. The combination failed to cause a strong decrease in hepatic triacylglycerol concentration, presumably due to the up-regulation of Cd36 by sesamin. Combination of sesamin and soybean phospholipid decreased the activity and mRNA levels of hepatic lipogenic enzymes in an additive fashion. Sesamin strongly increased the parameters of hepatic fatty acid oxidation enzymes. Soybean phospholipid increased hepatic activity of 3-hydroxyacyl-CoA dehydrogenase although it failed to affect the activity of other enzymes involved in fatty acid oxidation. Sesamin strongly increased hepatic concentration of carnitine. Sesamin and soybean phospholipid combination further increased this parameter, accompanying a parallel increase in mRNA expression of carnitine transporter. These changes can account for the strong decrease in serum triacylglycerol in rats fed a diet containing both sesamin and soybean phospholipid.

Influence of oral supplementation with sesamin on longevity of Caenorhabditis elegans and the host defense

PURPOSE

Nutritional control has been proposed as a potential therapy for slowing the senescence of immune function and decreasing mortality. This study investigated whether sesamin could modify host defense systems and extend the lifespan of the nematode Caenorhabditis elegans.

METHODS

Nematodes were fed standard food (the bacterium Escherichia coli strain OP50) supplemented with various doses of sesamin/γ-cyclodextrin inclusion compounds starting from young adulthood. The mean lifespan, muscle function, lipofuscin accumulation, protein carbonyl content, and stress resistance of the worms were examined. Then, C. elegans mutants harboring loss-of-function lesions in longevity- and host defense-related signaling pathways were supplemented with sesamin to identify the genes involved in the longevity effects.

RESULTS

Worms supplemented with sesamin displayed higher locomotion and prolongevity and produced offspring at levels similar to unsupplemented control animals. The growth curves of nematodes were similar to those of controls, suggesting that sesamin did not induce prolongevity effects through dietary restriction. Notably, sesamin made the worms more resistant to infection by Legionella pneumophila and more resistant to oxidative stressors such as paraquat and hydrogen peroxide and prolonged the lifespan of a mev-1 mutant that produces abundant superoxide anions. However, the accumulation of protein carbonyls and lipofuscin was similar in sesamin-exposed and control worms, suggesting that sesamin is unlikely to work simply as an antioxidant. Sesamin supplementation failed to extend the lifespan of loss-of-function mutants of daf-2, daf-16, pmk-1, and skn-1.

CONCLUSIONS

Sesamin enhances the host defense of C. elegans and increases the average lifespan via activation of both skn-1 (encoding a component of the p38 MAPK pathway) and daf-16 (encoding a component of the IGF-1 pathway).

Hypoglycaemic and hypolipidaemic activities of sesamin from sesame meal and its ability to ameliorate insulin resistance in KK-Ay mice

BACKGROUND

The ability of sesamin from sesame meal to ameliorate insulin resistance in KK-Ay mice (an animal model of type 2 diabetes) was evaluated.

RESULTS

Treatment with sesamin (100 or 50 mg kg(-1)) significantly decreased the level of fasting plasma glucose, glycosylated serum protein, serum insulin, triglycerides, cholesterol, free fatty acid and malondialdehyde content of livers. Treatment with sesamin significantly increased the content of hepatic glycogen, reduced glutathione and the activity of superoxide dismutase and glutathione peroxidase. Moreover, the insulin-binding capacity to liver crude plasma membranes increased and histopathological changes of the pancreas were ameliorated in the treatment group.

CONCLUSION

Sesamin has hypoglycaemic, hypolipidaemic and the ability to ameliorate insulin resistance in KK-Ay mice, which might be related to its effect on insulin receptors, and thus increases insulin sensitivity.

Effects of sesamin on streptozotocin (STZ)-induced NIT-1 pancreatic β-cell damage

The protective effect of sesamin (SES) from sesame meal on NIT-1 pancreatic β-cells damaged by streptozotocin (STZ) in vitro was investigated. The cell viability, insulin secretion, the activity of superoxide dismutase(SOD), glutathione peroxidase (GSHpx) and the content of reduced glutathione (GSH) increased significantly when incubated with SES (400, 200 μg mL⁻¹). The content of malondialdehyde (MDA), nitric oxide (NO) production, and the activity of NO synthase (NOS), inducible NOS (iNOS), decreased significantly when incubated with SES. The destructive changes of NIT-1 cells were ameliorated when treated with SES under microscopic observation. These data suggested that SES had obvious protective effect on NIT-1 pancreatic β-cells damaged by STZ, which might be related to its effects of decreasing levels of β-cell-destroying factors such as oxidative stress and NO synthesis.

Obtusilactone A and (-)-sesamin induce apoptosis in human lung cancer cells by inhibiting mitochondrial Lon protease and activating DNA damage checkpoints

Several compounds from Cinnamomum kotoense show anticancer activities. However, the detailed mechanisms of most compounds from C. kotoense remain unknown. In this study, we investigated the anticancer activity of obtusilactone A (OA) and (-)-sesamin in lung cancer. Our results show that human Lon is upregulated in non-small-cell lung cancer (NSCLC) cell lines, and downregulation of Lon triggers caspase-3 mediated apoptosis. Through enzyme-based screening, we identified two small-molecule compounds, obtusilactone A (OA) and (-)-sesamin from C. kotoense, as potent Lon protease inhibitors. Obtusilactone A and (-)-sesamin interact with Ser855 and Lys898 residues in the active site of the Lon protease according to molecular docking analysis. Thus, we suggest that cancer cytotoxicity of the compounds is partly due to the inhibitory effects on Lon protease. In addition, the compounds are able to cause DNA double-strand breaks and activate checkpoints. Treatment with OA and (-)-sesamin induced p53-independent DNA damage responses in NSCLC cells, including G(1) /S checkpoint activation and apoptosis, as evidenced by phosphorylation of checkpoint proteins (H2AX, Nbs1, and Chk2), caspase-3 cleavage, and sub-G(1) accumulation. In conclusion, OA and (-)-sesamin act as both inhibitors of human mitochondrial Lon protease and DNA damage agents to activate the DNA damage checkpoints as well induce apoptosis in NSCLC cells. These dual functions open a bright avenue to develop more selective chemotherapy agents to overcome chemoresistance and sensitize cancer cells to other chemotherapeutics.

Dietary lignans: physiology and potential for cardiovascular disease risk reduction

The present review of the literature on lignan physiology and lignan intervention and epidemiological studies was conducted to determine if lignans decrease the risks of cardiovascular disease in Western populations. Five intervention studies using flaxseed lignan supplements indicated beneficial associations with C-reactive protein, and a meta-analysis that included these studies also suggested lignans have a lowering effect on plasma total and low-density lipoprotein cholesterol. Three intervention studies using sesamin supplements indicated possible lipid- and blood pressure-lowering associations. Eleven human observational epidemiological studies examined dietary intakes of lignans in relation to cardiovascular disease risk. Five showed decreased risk with either increasing dietary intakes of lignans or increased levels of serum enterolactone (an enterolignan used as a biomarker of lignan intake), five studies were of borderline significance, and one was null. The associations between lignans and decreased risk of cardiovascular disease are promising, but they are yet not well established, perhaps due to low lignan intakes in habitual Western diets. At the higher doses used in intervention studies, associations were more evident.

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.

A randomized controlled trial of the effects of flaxseed lignan complex on metabolic syndrome composite score and bone mineral in older adults

A randomized double-blind placebo controlled study design was used to assess the effects of flaxseed lignan complex supplementation during exercise training on a metabolic syndrome composite score and osteoporosis risk in older adults. A total of 100 subjects (>or=50 years) were randomized to receive flaxseed lignan (543 mg.day-1 in a 4050 mg complex) or placebo while completing a 6 month walking program (30-60 min.day-1, 5-6 days.week-1). Fasting serum glucose, triacylglycerol (TAG), high-density lipoprotein (HDL) cholesterol, low-density lipoprotein cholesterol, total cholesterol, interleukin-6, and tumor necrosis factor-alpha were measured every 2 months, while body composition, bone mineral density, and resting blood pressure were assessed at baseline and at 6 months. A composite Z score of 6 risk factors for metabolic syndrome (fasting glucose, HDL cholesterol, TAG, abdominal adiposity, blood pressure, and inflammatory cytokines) was calculated at baseline and at 6 months. Men taking placebo increased metabolic syndrome composite Z score (p < 0.05), but there were no changes in the other groups. A significant group x sex x time interaction was noted for TAG (p = 0.017) and diastolic blood pressure (p = 0.046), with men taking flaxseed lignan decreasing diastolic blood pressure relative to men taking placebo, and men taking placebo increasing TAG relative to men taking flax lignan. There were no differences between groups for change in bone measures, body composition, lipoproteins, or cytokines. Males taking the flaxseed lignan complex reduced metabolic syndrome score relative to men taking placebo, but a similar trend was not seen in females. Flaxseed lignan had no effect on bone mineral density or content, body composition, lipoproteins, glucose, or inflammation.

Feedback inhibition of cholesterol biosynthesis by dietary cholesterol in experimental chronic renal failure

OBJECTIVE

Enhanced liver cholesterol synthesis is present in experimental chronic renal failure (CRF), even though cholesterol concentrations in blood and liver are increased, suggesting that CRF results in disturbed cholesterolegenesis feedback regulation.

DESIGN

This study sought to elucidate whether dietary cholesterol exerts inhibitory effects on liver cholesterologenesis in CRF rats.

METHODS

Male Wistar rats were used. Experimental CRF was achieved by a 5/6 nephrectomy model. Cholesterologenesis was measured (1) in vivo by tritiated water incorporation into cholesterol, and (2) in vitro (using liver slices) by [(14)C]-acetate and [(3)H]-mevalonate incorporation into cholesterol. In addition, the mRNA abundance of 3-hydroxy-3-methylglutaryl-CoA reductase, a rate-limiting enzyme in cholesterologenesis pathway, as well as its activity, was determined. Finally, the mRNA level of liver sterol regulatory element-binding protein-2, a nuclear transcription factor engaged in intracellular cholesterol homeostasis, was measured.

RESULTS

Experimental CRF was associated with significantly increased concentrations of serum and liver cholesterol. In vitro and in vivo cholesterologenesis was enhanced in CRF rats. A cholesterol-enriched diet resulted in a significant decrease in (1) in vivo and in vitro cholesterol synthesis, (2) 3-hydroxy-3-methylglutaryl-CoA reductase gene expression, and (3) the level of liver sterol regulatory element-binding protein-2 mRNA in CRF rats.

CONCLUSIONS

Despite elevated plasma and liver cholesterol concentrations, cholesterologenesis is increased in CRF rats. It is, however, inhibited by dietary cholesterol. These results suggest that a feedback inhibition of cholesterologenesis by dietary cholesterol is preserved in experimental CRF.

Gene expression microarray analysis of the effects of grape anthocyanins in mice: a test of a hypothesis-generating paradigm

The mechanism(s) through which fruits, vegetables, and whole grains favorably affect health is not well established. Using an anthocyanin-rich grape as a model, we examined the ability of an agnostic analytical approach using gene expression microarrays to generate novel testable hypotheses regarding the mechanisms of action of potentially healthful foods and food components. C57BL/6 mice were divided into 2 groups and fed a proatherogenic diet with or without a semipurified anthocyanin extract (70% anthocyanins) incorporated at a level of 0.1 mg/mL into the drinking water. After 6 weeks, compared with control mice, mice supplemented with anthocyanins tended to gain more weight and have increased adipose tissue mass, although these effects did not achieve statistical significance. Anthocyanin-supplemented mice had significantly reduced relative liver weights and heart weights. Serum lipids and inflammatory cytokines were not different between the groups. Gene expression microarray analysis of the liver and skeletal muscle identified a number of molecular pathways significantly affected by anthocyanin treatment. Two distinct clusters emerged. The first cluster included down-regulated pathways in both muscle and liver involving cellular defense, whereas the second included hepatic genes involved in energy metabolism. From these data, 3 hypotheses were developed for future investigation.

Effects of soy protein and isoflavone on hepatic fatty acid synthesis and oxidation and mRNA expression of uncoupling proteins and peroxisome proliferator-activated receptor gamma in adipose tissues of rats

Soy protein rich in isoflavones profoundly affects lipid metabolism in experimental animals. To distinguish the roles of the protein and isoflavone components of a soy protein preparation in regulating lipid metabolism, we compared the effects of diets containing methanol-washed soy protein low in isoflavone supplemented with a 0-, 0.5- and 4-g/kg isoflavone preparation on hepatic fatty acid metabolism and adipose tissue gene expression in rats. Diets containing soy protein irrespective of the isoflavone levels decreased the activities and mRNA expression of enzymes involved in hepatic fatty acid synthesis to similar levels. Methanol-washed soy protein compared to casein increased the mRNA expression of peroxisome proliferator-activated receptor (PPAR) alpha, and supplementing the soy protein diet with isoflavone further increased this parameter dose-dependently. However, methanol-washed soy protein compared to casein was totally ineffective in altering the activities and mRNA levels of enzymes involved in fatty acid oxidation. Supplementation of soy protein diets with isoflavone slightly increased these parameters. The mRNA level of uncoupling protein (UCP) 1 in brown adipose tissue was significantly increased and mRNA levels of UCP2 and 3, and PPARgamma2 tended to be higher in rats fed methanol-washed soy protein not supplemented with isoflavone than in the animals fed casein. Adding isoflavone to the soy protein diets dose-dependently increased these parameters. These results suggested that the protein rather than isoflavone component is primarily responsible for the physiological activity of soy protein rich in isoflavones in reducing hepatic lipogenesis. However, isoflavones may have a role in regulating heptic fatty acid oxidation and adipose tissue gene expression.

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.

Comparative analysis of sesame lignans (sesamin and sesamolin) in affecting hepatic fatty acid metabolism in rats

Effects of sesamin and sesamolin (sesame lignans) on hepatic fatty acid metabolism were compared in rats. Rats were fed either a lignan-free diet, a diet containing 0.6 or 2 g/kg lignan (sesamin or sesamolin), or a diet containing both sesamin (1.4 g/kg) and sesamolin (0.6 g/kg) for 10 d. Sesamin and sesamolin dose-dependently increased the activity and mRNA abundance of various enzymes involved in hepatic fatty acid oxidation. The increase was much greater with sesamolin than with sesamin. These lignans increased parameters of hepatic fatty acid oxidation in an additive manner when added simultaneously to an experimental diet. In contrast, they decreased the activity and mRNA abundance of hepatic lipogenic enzymes despite dose-dependent effects not being necessarily obvious. Sesamin and sesamolin were equally effective in lowering parameters of lipogenesis. Sesamolin accumulated in serum at 33- and 46-fold the level of sesamin at dietary concentrations of 0.6 and 2 g/kg, respectively. The amount of sesamolin accumulated in liver was 10- and 7-fold that of sesamin at the respective dietary levels. Sesamolin rather than sesamin can account for the potent physiological effect of sesame seeds in increasing hepatic fatty acid oxidation observed previously. Differences in bioavailability may contribute to the divergent effects of sesamin and sesamolin on hepatic fatty acid oxidation. Sesamin compared to sesamolin was more effective in reducing serum and liver lipid levels despite sesamolin more strongly increasing hepatic fatty acid oxidation.

Effect of dietary sesame oil as antioxidant on brain hippocampus of rat in focal cerebral ischemia

Oxidative stress may be regarded as an imbalance between free radical production and opposing antioxidant defenses. Free radical oxidative stress is implicated in rat cerebral ischemia and naturaceutical antioxidants are dietary supplements that have been reported to have neuroprotective activity. Many studies have reported dietary sesame oil (SO) as an effective antioxidant. In the present study the neuroprotective effect of dietary SO was evaluated against middle cerebral artery occlusion (MCAO)-induced cerebral ischemia injury in rats. Rats were fed on diet (20% SO) for 15 days. The middle cerebral artery of adult male Wistar rat was occluded for 2 h and reperfused for 22 h. The antioxidant properties of brain were measured as levels of reduced glutathione (GSH), glutathione-S-transferase (GST), glutathione peroxide (GPx), glutathione reductase (GR), catalase (CAT), superoxide dismutase (SOD) and thiobarbituric acid reactive substance (TBARS). A decrease in the activity of all the enzymatic and non-enzymatic antioxidants was observed along with an increase in lipid peroxidation (LPO) in MCAO group. The neurobehavioral activity of rats was also observed by using videopath analyzer. Dietary SO improved the antioxidant status in MCAO+SO group when compared with MCAO group. The results of neurobehavioral activity also support our biochemical data. The results obtained suggest protective effect of SO against cerebral ischemia in rat brain through their antioxidant properties.

Inhibitory effect of sesaminol glucosides on lipopolysaccharide-induced NF-κB activation and target gene expression in cultured rat astrocytes

The inflammatory reaction plays an important role in the pathogenesis of the neurodegenerative disorder including Alzheimer's disease (AD). Sesame lignan compounds such as sesaminol glucosides (SG) exhibit a range of pharmacological activities including anti-oxidative and anti-inflammatory action. In this study, we tried to elucidate possible effects of SG on lipopolysaccharide (LPS)-induced inflammatory reaction and its underlying mechanism in cultured astrocytes. SG (10-100 microg/ml) inhibited LPS-induced generation of nitric oxide (NO) and reactive oxygen species (ROS), as well as inhibited LPS-induced cytosolic phospholipase A2 (cPLA2), cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS) expression dose-dependently. This inhibitory effect of SG on NO and ROS generation was enforced by addition of glutathione (GSH) in culture. In addition, SG prevented LPS-induced DNA binding and transcriptional activity of nuclear factor KappaB (NF)-kappaB. Consistent with the inhibitory effect on NF-kappaB activity, SG inhibits phosphorylation and degradation of inhibitory KappaB (IkappaB), thereby translocation of p50 of NF-kappaB. These data show that SG has an anti-inflammatory effect through inhibition of NF-kappaB, and may be a useful agent for prevention of inflammatory disease like AD.