Antiatherosclerotic effects of dietary supplementations of garlic and turmeric: Restoration of endothelial function in rats

Herbal Products as Complementary or Alternative Medicine for the Management of Hyperglycemia and Dyslipidemia in Patients with Type 2 Diabetes: Current Evidence Based on Findings of Interventional Studies

Type 2 diabetes (T2D) is known as a major public health problem with a noticeable adverse impact on quality of life and health expenditures worldwide. Despite using routine multiple pharmacological and nonpharmacological interventions, including diet therapy and increasing physical activity, controlling this chronic disease remains a challenging issue, and therapeutic goals are often not achieved. Therefore, recently, other therapeutic procedures, such as using herbal products and functional foods as complementary or alternative medicine (CAM), have received great attention as a new approach to managing T2D complications, according to the literature. We reviewed the existing evidence that supports using various fundamental medicinal herbs, including cinnamon, saffron, ginger, jujube, turmeric, and barberry, as CAM adjunctive therapeutic strategies for T2D patients. The current review addressed different aspects of the potential impact of the abovementioned herbal products in improving glycemic indices and lipid profiles, including the effect size reported in the studies, their effective dose, possible side effects, herbs-drug interactions, and their potential action mechanisms.

Bioactive molecules from terrestrial and seafood resources in hypertension treatment: focus on molecular mechanisms and targeted therapies

Hypertension (HTN), a complex cardiovascular disease (CVD), significantly impacts global health, prompting a growing interest in complementary and alternative therapeutic approaches. This review article seeks to provide an up-to-date and thorough summary of modern therapeutic techniques for treating HTN, with an emphasis on the molecular mechanisms of action found in substances found in plants, herbs, and seafood. Bioactive molecules have been a significant source of novel therapeutics and are crucial in developing and testing new HTN remedies. Recent advances in science have made it possible to understand the complex molecular mechanisms underlying blood pressure (BP)-regulating effects of these natural substances better. Polyphenols, flavonoids, alkaloids, and peptides are examples of bioactive compounds that have demonstrated promise in influencing several pathways involved in regulating vascular tone, reducing oxidative stress (OS), reducing inflammation, and improving endothelial function. The article explains the vasodilatory, diuretic, and renin-angiotensin-aldosterone system (RAAS) modifying properties of vital plants such as garlic and olive leaf. Phytochemicals from plants are the primary in traditional drug development as models for novel antihypertensive drugs, providing diverse strategies to combat HTN due to their biological actions. The review also discusses the functions of calcium channel blockers originating from natural sources, angiotensin-converting enzyme (ACE) inhibitors, and nitric oxide (NO) donors. Including seafood components in this study demonstrates the increased interest in using bioactive chemicals originating from marine sources to treat HTN. Omega-3 fatty acids, peptides, and minerals obtained from seafood sources have anti-inflammatory, vasodilatory, and antioxidant properties that improve vascular health and control BP. Overall, we discussed the multiple functions of bioactive molecules and seafood components in the treatment of HTN.

The Blood-Brain Barrier: Much More Than a Selective Access to the Brain

The blood-brain barrier is a dynamic structure, collectively referred to as the neurovascular unit. It is responsible for the exchange of blood, oxygen, ions, and other molecules between the peripheral circulation and the brain compartment. It is the main entrance to the central nervous system and as such critical for the maintenance of its homeostasis. Dysfunction of the blood-brain barrier is a characteristic of several neurovascular pathologies. Moreover, physiological changes, environmental factors, nutritional habits, and psychological stress can modulate the tightness of the barrier. In this contribution, we summarize our current understanding of structure and function of this important component of the brain. We also describe the neurological deficits associated with its damage. A special emphasis is placed in the effect of the exposure to xenobiotics and pollutants in the permeability of the barrier. Finally, current protective strategies as well as the culture models to study this fascinating structure are discussed.

Natural Products Counteracting Cardiotoxicity during Cancer Chemotherapy: The Special Case of Doxorubicin, a Comprehensive Review

Cardiotoxicity is a frequent undesirable phenomenon observed during oncological treatment that limits the therapeutic dose of antitumor drugs and thus may decrease the effectiveness of cancer eradication. Almost all antitumor drugs exhibit toxic properties towards cardiac muscle. One of the underlying causes of cardiotoxicity is the stimulation of oxidative stress by chemotherapy. This suggests that an appropriately designed diet or dietary supplements based on edible plants rich in antioxidants could decrease the toxicity of antitumor drugs and diminish the risk of cardiac failure. This comprehensive review compares the cardioprotective efficacy of edible plant extracts and foodborne phytochemicals whose beneficial activity was demonstrated in various models in vivo and in vitro. The studies selected for this review concentrated on a therapy frequently applied in cancer, anthracycline antibiotic-doxorubicin-as the oxidative stress- and cardiotoxicity-inducing agent.

β-Caryophyllene, a natural bicyclic sesquiterpene attenuates β-adrenergic agonist-induced myocardial injury in a cannabinoid receptor-2 dependent and independent manner

The downregulation of cannabinoid type-2 receptors (CB2R) have been reported in numerous diseases including cardiovascular diseases (CVDs). The activation of CB2R has recently emerged as an important therapeutic target to mitigate myocardial injury. We examined whether CB2R activation can protect against isoproterenol (ISO)-induced myocardial injury (MI) in rats. In the present study, we investigated the cardioprotective effect of β-caryophyllene (BCP), a naturally occurring dietary cannabinoid in rat model of MI. Rats were pre- and co-treated with BCP (50 mg/kg, orally) twice daily for 10 days along with subcutaneous injection of ISO (85 mg/kg) at an interval of 24 h for two days (9th and 10th days). AM630 (1 mg/kg), a CB2 receptor antagonist, was injected intraperitoneal as a pharmacological challenge prior to BCP treatment to reveal CB2R-mediated cardioprotective mechanisms of BCP. Desensitization of beta-adrenergic receptor (β-AR) signaling, receptor phosphorylation and recruitment of adapter β-arrestins were observed in ISO-induced MI in rats. ISO injections caused impaired cardiac function, elevated the levels of serum cardiac marker enzymes, and enhanced oxidative stress markers along with altered PI3K/Akt and NrF2/Keap1/HO-1 signaling pathways. ISO also promoted lysosomal dysfunction along with activation of NLRP3 inflammasomes and TLR4-NFκB/MAPK signaling and triggered rise in proinflammatory cytokines. There was a concomitant mitochondrial dysfunction followed by the activation of endoplasmic reticulum (ER) stress-mediated Hippo signaling and intrinsic pathway of apoptosis as well as altered autophagic flux/mTOR signaling in ISO-induced MI. Furthermore, ISO also triggered dyslipidemia evidenced by altered lipids, lipoproteins and lipid marker enzymes along with ionic homeostasis malfunction. However, treatment with BCP resulted in significant protective effects on all biochemical and molecular parameters analyzed. The cardioprotective effects were further strengthened by preservation of cardiomyocytes and cell organelles as observed in histopathological and ultrastructural studies. Interestingly, treatment with AM630, a CB2R antagonist was observed to abrogate the protective effects of BCP on the biochemical and molecular parameters except hyperlipidemia and ionic homeostasis in ISO-induced MI in rats. The present study findings demonstrate that BCP possess the potential to protect myocardium against ISO-induced MI in a CB2-dependent and independent manner.

Effect of eight-week curcumin supplementation with endurance training on glycemic indexes in middle age women with type 2 diabetes in Iran, A preliminary study

BACKGROUND AND AIMS

The purpose of this study was to determine the effects of curcumin supplementation & endurance training on glycemic indexes in middle-aged women with type 2 diabetes.

METHODS

40 middle-aged women with type 2 diabetes were randomly divided into four groups (control, curcumin, training & curcumin + training). Endurance training protocol included running on treadmill for eight weeks, three sessions per week and each session for 45-60 min, with a maximum intensity of 50-70% of MHR. The experimental groups received a supplementation of curcumin as a daily dose of 80 mg curcumin soft gel for 8 weeks while the control group was subjected to no supplementation or exercise during this period. One day before and one day after the eight-week experimental period, blood samples were taken from the subjects to measure the glycemic indexes, including fasting blood glucose, glycosylated hemoglobin, and serum insulin levels. T-test and two-way covariance analysis tests were used for analyzing the findings at a significant level of less than 0.05.

RESULTS

Eight weeks of curcumin supplementation and endurance training, whether done separately or simultaneously, significantly reduced fasting blood glucose, glycosylated hemoglobin and serum insulin levels (P < 0.05). The combination of curcumin supplementation and endurance training compared to the other two interventions caused a significant further decrease in these glycemic indexes (P < 0.05).

CONCLUSION

The findings of this study showed that eight weeks of curcumin supplementation and endurance training helped each other in improving the glycemic indexes of women with type 2 diabetes.

Nootkatone, a Dietary Fragrant Bioactive Compound, Attenuates Dyslipidemia and Intramyocardial Lipid Accumulation and Favorably Alters Lipid Metabolism in a Rat Model of Myocardial Injury: An In Vivo and In Vitro Study

In the present study, we assessed whether nootkatone (NKT), a sesquiterpene in edible plants, can provide protection against dyslipidemia, intramyocardial lipid accumulation, and altered lipid metabolism in a rat model of myocardial infarction (MI) induced by subcutaneous injections of isoproterenol (ISO, 85 mg/kg) on days 9 and 10. The rats were pre- and co-treated with NKT (10 mg/kg, p.o.) administered daily for 11 days. A significant reduction in the activities of myocardial creatine kinase and lactate dehydrogenase, as well as non-enzymatic antioxidants, and alterations in lipids and lipoproteins, along with a rise in plasma lipid peroxidation and intramyocardial lipid accumulation, were observed in ISO-treated rats. ISO administration induced alterations in the activities of enzymes/expressions that played a significant role in altering lipid metabolism. However, NKT treatment favorably modulated all biochemical and molecular parameters altered by ISO and showed protective effects against oxidative stress, dyslipidemia, and altered lipid metabolism, attributed to its free-radical-scavenging and antihyperlipidemic activities in rats with ISO-induced MI. Additionally, NKT decreased the accumulation of lipids in the myocardium as evidenced from Oil red O staining. Furthermore, the in vitro observations demonstrate the potent antioxidant property of NKT. The present study findings are suggestive of the protective effects of NKT on dyslipidemia and the underlying mechanisms. Based on our findings, it can be suggested that NKT or plants rich in NKT can be promising for use as a phytopharmaceutical or nutraceutical in protecting the heart and correcting lipid abnormalities and dyslipidemia, which are risk factors for ischemic heart diseases.

Prevailing Knowledge on the Bioavailability and Biological Activities of Sulphur Compounds from Alliums: A Potential Drug Candidate

Allium sativum (garlic) is widely known and is consumed as a natural prophylactic worldwide. It produces more than 200 identified chemical compounds, with more than 20 different kinds of sulfide compounds. The sulfide compounds particularly are proven to contribute to its various biological roles and pharmacological properties such as antimicrobial, antithrombotic, hypoglycemic, antitumour, and hypolipidemic. Therefore, it is often referred as disease-preventive food. Sulphur-containing compounds from A. sativum are derivatives of S-alkenyl-l-cysteine sulfoxides, ajoene molecules, thiosulfinates, sulfides, and S-allylcysteine. This review presents an overview of the water-soluble and oil-soluble sulphur based phytochemical compounds present in garlic, highlighting their mechanism of action in treating various health conditions. However, its role as a therapeutic agent should be extensively studied as it depends on factors such as the effective dosage and the suitable method of preparation.

Allicin disrupts cardiac Cav1.2 channels via trafficking

CONTEXT

Allicin is a potential antiarrhythmic agent. The antiarrhythmic properties of allicin rely on its blockade of various cardiac ion channels. The l-type calcium (Cav1.2) channel provides a pivotal substrate for cardiac electrophysiologic activities. The mechanism of allicin on Cav1.2 remains unclear.

OBJECTIVE

This study evaluated the potential of allicin on the synthesis and trafficking of Cav1.2 channels.

MATERIALS AND METHODS

Primary cardiomyocytes (CMs) from neonatal Sprague-Dawley (SD) rats were exposed to allicin (0, 0.0001, 0.001, 0.01, 0.1, 1, 10, 100 μg/mL) for 24 and 48 h. The CellTiter-Glo assay was performed to measure CM viability. Western blot with grayscale analysis and confocal laser scanning microscopy were used to evaluate the effects of allicin on the synthesis and trafficking of Cav1.2 channel proteins in primary CMs.

RESULTS

There was no significant difference in apoptotic toxicity from the actual cell viability (p > 0.05) in any group (0, 0.0001, 0.001, 0.01, 0.1, 1, 10, 100 μg/mL allicin), except that viability in the 0.001 and 0.01 μg/mL groups at 24 h were significantly greater (137.37 and 135.96%) (p < 0.05). Western blot with grayscale analysis revealed no substantial inhibition by allicin of the synthesis of Cav1.2 proteins. Confocal laser scanning microscopy revealed trafficking dysfunction of Cav1.2 channels caused by allicin in primary CMs.

CONCLUSION

This study is the first to demonstrate that allicin inhibits cardiac Cav1.2 channels by disrupting trafficking, possibly mediating its antiarrhythmic benefits. Therefore, allicin might serve as a new antiarrhythmic agent in the future.

Effect of turmeric on glycemic status, lipid profile, hs-CRP, and total antioxidant capacity in hyperlipidemic type 2 diabetes mellitus patients

Diabetes mellitus is the most common metabolic disorder worldwide. This study examined the effect of turmeric supplementation on glycemic status, lipid profile, hs-CRP and total antioxidant capacity in hyperlipidemic type 2 diabetic patients. In this double-blind, randomized clinical trial, 80 hyperlipidemic type 2 diabetic patients were divided into turmeric (2,100 mg powdered rhizome of turmeric daily) and placebo groups for 8 weeks. Body weight, fasting plasma glucose, hemoglobin A1c (HbA1c), serum insulin, triglyceride (TG), total cholesterol, low density lypoprotein cholesterol (LDL-c), high density lypoprotein cholesterol, apolipoprotein A1, apolipoprotein B, high sensitivity C-reactive protein (hs-CRP), and total antioxidant capacity were measured before and after intervention. Statistical analysis was carried out using paired and independent t and chi-square tests. Seventy five patients completed the study. The turmeric group showed significant decreases in body weight, TG, and LDL-c compared with baseline (p value < 0.05). Body mass index, TG, and total cholesterol decreased significantly in the turmeric group compared with the placebo group (p value < 0.05). No significant changes were observed in other parameters between the two groups after intervention (p value < 0.05). Turmeric improved some fractions of lipid profile and decreased body weight in hyperlipidemic patients with type 2 diabetes. It had no significant effect on glycemic status, hs-CRP, and total antioxidant capacity in these patients.

Antihypertensive effect of allicin in dexamethasone-induced hypertensive rats

BACKGROUND

Glucocorticoid is among the most commonly prescribed medicine. Unfortunately, Excess glucocorticoid level leads hypertension in 80-90% patients. Garlic (Allium sativum) has been used since ancient times and even nowadays as a part of popular medicine for various ailments and physiological disorders. Hence this study was undertaken to investigate the antihypertensive activity of allicin in dexamethasone induced hypertension in wistar rats.

METHODS

The animals were randomly divided into four groups comprising of six rats per group. Hypertension was induced by subcutaneous injection of dexamethasone (10 μg/rat/day) in hypertensive rats. Two hypertensive group animals were treated with nicorandil (6 mg/kg/day, po) and allicin (8 mg/kg/day, po) respectively for 8 weeks. While systolic blood pressure (SBP) was measured by the tail-cuff method weekly up to 8 weeks.

RESULTS

Dexamethasone treatment resulted in significant increase in SBP while allicin treatment significantly decreases the SBP. Thus, this study confirmed that allicin treatment for 8 weeks partially reverse dexamethasone induced hypertension in rats. Allicin treatment also attenuated dexamethasone-induced anorexia and loss of total body weight.

CONCLUSION

This result suggests antihypertensive effects of allicin in dexamethasone induced hypertension. However, further studies are needed to explore the detailed mechanism of antihypertensive effect of allicin.

Allitridin reduces I Kr current by disrupting the trafficking of human ether-à-go-go-related gene channels

OBJECTIVES

To investigate the effects of allitridin on human ether-à-go-go-related gene (hERG) channels.

METHODS

We used whole-cell patch clamping and laser confocal scanning microscopy to evaluate the effects of allitridin on hERG currents and the membrane expression of the hERG protein expressed in HEK 293 cells.

RESULTS

The amplitude of IKr showed a concentration-dependent decrease with increasing allitridin concentration. Additionally, alterations in the gating properties of hERG channels were also confirmed. Allitridin does not alter the voltage- and time-dependent activation of hERG channels, the gating properties of hERG channel inactivation over time or the recovery from inactivation, but allitridin does cause alterations in the steady-state inactivation and the deactivation of hERG channels. We further evaluated the influence of allitridin on membrane expression of the hERG protein. Images of allitridin-treated cells showed a reduction in hERG protein on the membrane and retention in the cytoplasm.

CONCLUSIONS

To the best of our knowledge this is the first study to show that allitridin reduces the IKr current by impairing the trafficking of hERG channels. The results may demonstrate that allitridin could be a promising candidate for the prevention and treatment of arrhythmia-related diseases.

Discrimination of multi-origin chinese herbal medicines using gas chromatography-mass spectrometry-based fatty acid profiling

Multi-origin Chinese herbal medicines, with herbs originating from more than one species of plants, is a common phenomenon but an important issue in Traditional Chinese Medicines (TCMs). In the present study, a gas chromatography-mass spectrometry (GC-MS)-based fatty acid profiling approach to rapidly discriminate multi-origin Chinese medicines in terms of species and medicinal parts was proposed and validated using tuberous roots (Curcumae Radix) and rhizomes (Curcumae Rhizoma and Curcumae Longae Rhizoma) derived from four Curcuma species (e.g., C. wenyujin, C. kwangsiensis, C. phaeocaulis and C. longa) as models. Both type and content of fatty acids varied among different species of either tuberous roots or rhizomes, indicating each species has its own fatty acid pattern. Orthogonal partial least squares discriminant analysis (OPLS-DA) and hierarchical clustering analysis (HCA) based on dataset of global fatty acid profiling showed that either tuberous roots or rhizomes samples could be clearly classified into four clusters according to their species. Furthermore, those tested samples could also be discriminated in terms of their medicinal parts (e.g., tuberous root and rhizome). Our findings suggest that the proposed GC-MS-based fatty acid profiling followed by multivariate statistical analysis provides a reliable platform to discriminate multi-origin Chinese herbal medicines according to species and medicinal parts, which will be helpful for ensuring their quality, safety and efficacy.

Garlic and cardioprotection: insights into the molecular mechanisms

Garlic is widely recognized for its immense therapeutic potential. Garlic has been shown to exert its beneficial effects against a wide spectrum of diseases, including cancer, diabetes, and microbial infections, as well as immunological and cardiovascular disorders. Most of the research on garlic has indicated that garlic and its active compounds are effective in reducing cardiovascular and metabolic risk by normalizing abnormal plasma lipids, oxidized low density lipoproteins, abnormal platelet aggregation, high blood pressure, and cardiac injury. Some of the beneficial effects of dietary garlic against cardiovascular disorders are mediated via the generation of hydrogen sulfide and nitric oxide in cardiomyocytes and endothelial cells. Garlic has the potential to protect the heart against myocardial infarction, doxorubicin-induced cardiotoxicity, arrhythmia, hypertrophy, and ischemia-reperfusion injury. The induction of cardiac endogenous antioxidants and the reduction of lipid peroxidation by garlic has been reported by several different groups. Other mechanisms, such as regulating ion channels, modulating Akt signaling pathways, histone deacetylase inhibition, and cytochrome P450 inhibition, could be responsible for the cardioprotective effect of garlic. Although several mechanisms have been identified for the cardioprotective effect of garlic, there is a need for further research to identify the specific molecular mechanism of cardioprotection in different cardiac diseases.

Garlic in health and disease

The present article reviews the historical and popular uses of garlic, its antioxidant, haematological, antimicrobial, hepatoprotective and antineoplastic properties and its potential toxicity (from sulfoxide). Garlic has been suggested to affect several cardiovascular risk factors. It has also been shown that garlic and its organic allyl sulfur components are effective inhibitors of the cancer process. Since garlic and its constituents can suppress carcinogen formation, bioactivation and tumour proliferation, it is imperative that biomarkers be established to identify which individuals might benefit most. Garlic powder, aged garlic and garlic oil have demonstrated antiplatelet and anticoagulant effects by interfering with cyclo-oxygenase-mediated thromboxane synthesis. Garlic has also been found to have synergistic effects against Helicobacter pylori with a proton pump inhibitor. The active compound allicin may affect atherosclerosis not only by acting as an antioxidant, but also by other mechanisms, such as lipoprotein modification and inhibition of LDL uptake and degradation by macrophages. Freshly prepared garlic homogenate protects against isoniazid+rifampicin-induced liver injury in experimental animal models. Several mechanisms are likely to account for this protection.

Garlic Oil Alleviates MAPKs- and IL-6-mediated Diabetes-related Cardiac Hypertrophy in STZ-induced DM Rats

Garlic oil has been reported to protect the cardiovascular system; however, the effects and mechanisms behind the cardioprotection of garlic oil on diabetes-induced cardiaomyopathy are unclear. In this study, we used streptozotocin (STZ)-induced diabetic rats to investigate whether garlic oil could protect the heart from diabetes-induced cardiomyopathy. Wistar STZ-induced diabetic rats received garlic oil (0, 10, 50 or 100 mg kg^_1 body weight) by gastric gavage every 2 days for 16 days. Normal rats without diabetes were used as control. Cardiac contractile dysfunction and cardiac pathologic hypertrophy responses were observed in diabetic rat hearts. Cardiac function was examined using echocardiography. In addition to cardiac hypertrophy-related mitogen-activated protein kinases (MAPK) pathways (e.g., p38, c-Jun N-terminal kinases (JNK) and extracellularly responsive kinase (ERK1/2)), the IL-6/MEK5/ERK5 signaling pathway was greatly activated in the diabetic rat hearts, which contributes to the up-regulation of cardiac pathologic hypertrophy markers including atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP), and leads to cardiac contractile dysfunction. Garlic oil treatment significantly inhibited the up-regulation in MAPK (e.g., p38, JNK and ERK1/2) and IL-6/MEK5/ERK5 signaling pathways in the diabetic rat hearts, reducing the levels of cardiac pathologic hypertrophy markers such as ANP and BNP, and improving the cardiac contractile function. Collectively, data from these studies demonstrate that garlic oil shows the potential cardioprotective effects for protecting heart from diabetic cardiomyopathy.

Garlic: nature's protection against physiological threats

Currently reliance on natural products is gaining popularity to combat various physiological threats including oxidative stress, cardiovascular complexities, cancer insurgence, and immune dysfunction. The use of traditional remedies may encounter more frequently due to an array of scientific evidence in their favor. Garlic (Allium sativum) holds a unique position in history and was recognized for its therapeutic potential. Recent advancements in the field of immunonutrition, physiology, and pharmacology further explored its importance as a functional food against various pathologies. Extensive research work has been carried out on the health promoting properties of garlic, often referred to its sulfur containing metabolites i.e. allicin and its derivatives. Garlic in its preparations are effective against health risks and even used as dietary supplements such as age garlic extract (AGE) and garlic oil etc. Its components/formulations can scavenge free radicals and protect membranes from damage and maintains cell integrity. It also provides cardiovascular protection mediated by lowering of cholesterol, blood pressure, anti-platelet activities, and thromboxane formation thus providing protection against atherosclerosis and associated disorders. Besides this, it possesses antimutagenic and antiproliferative properties that are interesting in chemopreventive interventions. Several mechanisms have been reviewed in this context like activation of detoxification phase-I and II enzymes, reactive oxygen species (ROS) generation, and reducing DNA damage etc. Garlic could be useful in preventing the suppression of immune response associated with increased risk of malignancy as it stimulates the proliferation of lymphocytes, macrophage phagocytosis, stimulates the release of interleukin-2, tumor necrosis factor-alpha and interferon-gamma, and enhances natural killer cells. In this paper much emphasis has been placed on garlic's ability to ameliorate oxidative stress, core role in cardiovascular cure, chemopreventive strategies, and indeed its prospective as immune booster.

Masou salmon (Oncorhynchus masou) ethanol extract decreases 3-hydroxy-3-methylglutaryl coenzyme A reductase expression in diet-induced obese mice

This study was designed to evaluate the hypocholesterolemic effects of masou salmon 70% ethanol extract (MSE) and to determine the molecular mechanism by which MSE exerts its effects in high-fat (HF) diet-induced obese mice. We hypothesize that the MSE may contain abundant n-3 fatty acids, so a diet containing MSE may also have hypolipidemic effects by assessing several key gene expressions in cholesterol metabolism such as the low-density lipoprotein (LDL) receptor, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, and cholesterol 7alpha-hydroxylase (CYP7A1). To test this hypothesis, C57BL/6J mice were fed a 40% HF diet for 5 weeks, after which time the animals were fed an HF diet containing 0 mg/kg, 75 mg/kg, or 150 mg/kg MSE (HF, HF + MSE 1, and HF + MSE 2 groups, respectively) for an additional 4 weeks (n = 8 in each group, for a total of 24 mice). We found that feeding MSE with an HF diet prevented hypercholesterolemia in diet-induced obese mice; daily MSE feeding reduced total cholesterol levels in plasma and liver by 12.3% and 16.2%, respectively. Furthermore, we examined the expression of key cholesterol metabolism genes by reverse transcription-polymerase chain reaction and found that messenger RNA levels of HMG-CoA reductase were decreased by up to 5-fold, but the expression of both LDL receptor and CYP7A1 did not change. Thus, MSE may exert its hypocholesterolemic effect by altering the expression of HMG-CoA reductase.

Hypocholesterolemic effect of stilbenes containing extract-fraction from Cajanus cajan L. on diet-induced hypercholesterolemia in mice

Cajanus cajan (L) is a natural plant which contains a lot of potential active components. In the present study, we identified the effects of the stilbenes containing extract-fraction from Cajanus cajan L (sECC) on diet-induced (for 4 weeks) hypercholesterolemia in Kunming mice. All experimental mice were divided into 5 groups: control group, model group, sECC-treated with 200 or 100 mg/kg/day, and simvastatin group. The effects of sECC were investigated by monitoring serum and liver lipid profile (cholesterol homeostasis and triglyceride) as well as serum superoxide dismutase activity in those mice. To further explore the mechanism of sECC, hepatic 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-CoA reductase), cholesterol 7α-hydroxylase (CYP7A1), and low density lipoprotein receptor (LDL receptor) expressions in cholesterol homeostasis were analyzed by reverse transcription PCR. After 4 weeks pretreatment, compared with model group, the increased serum and hepatic total cholesterol were markedly attenuated by sECC (200 mg/kg) by 31.4% and 22.7% (p<0.01), respectively, the triglyceride levels of serum and liver were also lowered by 22.98% and 14.39%, respectively. At the same time, serum LDL cholesterol decreased by 52.8% (p<0.01) accompanied with the activities of serum superoxide dismutase increased by 20.98%. Atherogenic index and body weight were also reduced markedly. The mRNA expressions of HMG-CoA reductase, CYP7A1, and LDL-receptor were significantly enhanced in the mice administered with sECC (200 mg/kg/day), whereas those expressions were suppressed by the hypercholesterolemic diet. These data indicate that sECC reduces the atherogenic properties of dietary cholesterol in mice. Its hypocholesterolemic effect may involve enhancement of the hepatic LDL-receptor and cholesterol 7alpha-hydroxylase expression levels and bile acid synthesis.

Prevention of arsenic-induced hepatic apoptosis by concomitant administration of garlic extracts in mice

Garlic is well known as a folk remedy for a variety of ailments since ancient times, however, very few studies are available suggesting its beneficial role against arsenic toxicity pertaining to its ability to eliminate arsenic from the blood and soft tissues and in reversal of arsenic-induced oxidative stress in affected tissues. The present study was planned to investigate the protective efficacy of aqueous garlic extract using two different doses on parameters suggestive of hepatic injury, tissue oxidative stress and mobilization of arsenic. Further, an attempt to understand the mechanism of arsenic in inducing hepatic apoptosis was also studied. Results of the present study suggested that arsenic administration in mice caused generation of reactive oxygen species (ROS) causing apoptosis through mitochondria-mediated pathway. The ROS generation in hepatic tissue reverted to normal values after co-administration of garlic extracts. The study provides significant evidence that garlic extracts contain strong anti-oxidant property which could be beneficial in preventing arsenic-induced toxicity in cells. However, further research is required to determine whether the results from animal studies are applicable to humans before garlic can be recommended as a putative agent against arsenic toxicity.

Antioxidative action of aspirin on endothelial function in hypercholesterolaemic rats

The role of aspirin on vascular endothelial changes during hypercholesterolaemia prior to development of actual atherosclerotic lesions is not known. Therefore, in the present study, we tested the hypothesis that aspirin by its antioxidant action improves endothelial function in a rat model of hypercholesterolaemia. Hypercholesterolaemia was induced in Wistar rats by feeding a 1% cholesterol-rich diet for 10 weeks. Lipid profile, lipid peroxidation and reduced glutathione were estimated in serum. Endothelial function and beta(2)-adrenoceptor activity was tested by studying the dose-response relationship of acetylcholine and isoproterenol, respectively, on isolated aortic tissues in an organ bath setup. Hypercholesterolaemic rats showed a significant increase in total cholesterol, low-density lipoprotein cholesterol (LDL-C) and very low-density lipoprotein cholesterol (VLDL-C), and a significant fall in high-density lipoprotein cholesterol (HDL-C) compared to the control rats. Isolated aortic tissues from hypercholesterolaemic rats showed endothelial dysfunction and decreased sensitivity to beta(2)-adrenoceptor. Treatment with aspirin was associated with a fall in total cholesterol, LDL-C and VLDL-C, and a significant rise in serum HDL-C. Aspirin treatment also restored endothelial function and beta(2)-adrenoceptor activity. Hypercholesterolaemic rats showed free radical generation, evident by increase in serum lipid peroxidation and reduction in serum reduced glutathione content compared to the control rats. Aspirin treatment was associated with reduction in free radical stress evident by decreased lipid peroxidation and significantly prevented reduction in glutathione content compared to hypercholesterolaemic controls. Aspirin improves endothelial function and beta(2)-adrenoceptor activity during experimentally induced hypercholesterolaemia in rats, possibly due to an antioxidant effect.

Effect of cinnamon and turmeric on urinary oxalate excretion, plasma lipids, and plasma glucose in healthy subjects

BACKGROUND

High oxalate intake resulting from consuming supplemental doses of cinnamon and turmeric may increase risk of hyperoxaluria, a significant risk factor for urolithiasis.

OBJECTIVE

This study assessed urinary oxalate excretion from supplemental doses of cinnamon and turmeric as well as changes in fasting plasma glucose, cholesterol, and triacylglycerol concentrations.

DESIGN

Eleven healthy subjects, aged 21-38 y, participated in an 8-wk, randomly assigned, crossover study that involved the ingestion of supplemental doses of cinnamon and turmeric for 4-wk periods that provided 55 mg oxalate/d. Oxalate load tests, which entailed the ingestion of a 63-mg dose of oxalate from the test spices, were performed after each 4-wk experimental period and at the study onset with water only (control treatment). Fasting plasma glucose and lipid concentrations were also assessed at these time points.

RESULTS

Compared with the cinnamon and control treatments, turmeric ingestion led to a significantly higher urinary oxalate excretion during the oxalate load tests. There were no significant changes in fasting plasma glucose or lipids in conjunction with the 4-wk periods of either cinnamon or turmeric supplementation.

CONCLUSIONS

The percentage of oxalate that was water soluble differed markedly between cinnamon (6%) and turmeric (91%), which appeared to be the primary cause of the greater urinary oxalate excretion/oxalate absorption from turmeric. The consumption of supplemental doses of turmeric, but not cinnamon, can significantly increase urinary oxalate levels, thereby increasing risk of kidney stone formation in susceptible individuals.

The bioactivity of processed garlic (Allium sativum L.) as shown in vitro and in vivo studies on rats

Garlic (Allium sativum L.) is widely used as an obligatory part in many cooked dishes loosing during this process a certain part of its bioactivity. Antioxidant capacity measured by the ferric-reducing/antioxidant power (FRAP) method and by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical assay was the highest in raw and in a short time processed garlic samples by cooking. 70 Wistar rats were randomly divided into 10 diet groups, each of seven. They were named Control, NPG, PG1, PG2, PG3, Chol, Chol/NPG, Chol/PG1, Chol/PG2 and Chol/PG3. The rats of the Control group were fed basal diet (BD), which included wheat starch, casein, soybean oil, cellulose, mineral and vitamin mixtures. To the BD of the nine other groups were added 25mg of lyophilized non processed garlic equivalent of 500 mg non processed garlic/kg body weight (NPG), the same quantity of processed garlic for 20, 40 and 60 min for PG1, PG2 and PG3, respectively, 1% of cholesterol (Chol), 1% of cholesterol and 25mg/kg body weight of lyophilized non processed garlic (Chol/NPG), 1% of cholesterol and the same quantity of processed garlic for 20, 40 and 60 min for Chol/PG1, Chol/PG2 and Chol/PG3, respectively. The dose of 500 mg (25mg of lyophilized garlic/kg body weight) was chosen as the most effective (Banerjee, S.K., Maulik, M., Mancahanda, S.C., Dinda, A.K., Gupta, S.K., Maulik, S.K., 2002. Dose-dependent induction of endogenous antioxidants in rat heart by chronic administration of garlic. Life Sciences 70, pp. 1509-1518). Plasma lipid profile and the total antioxidant capacity in rats significantly differed in diet groups with addition of garlic samples cooked for a long time. In summary, garlic cooked for a short time preserves a high bioactivity of non processed garlic. The diet supplemented with these samples and cholesterol improved lipid indices, decreased fibrinogen and increased antioxidant activity in plasma of rats. Therefore, for preservation of garlic bioactivity optimal regime has to be used.

A systematic review of mechanisms by which natural products of plant origin evoke vasodilatation

This article reviews the body of work aimed at elucidating the mechanisms of action by which natural products of plant origin exert a vasodilatory effect at the level of the vasculature. The search was restricted to 4 mechanisms: the nitric oxide system and (or) reactive oxygen species, the eicosanoid system, potassium channel function, and calcium channel function. The National Library of Medicine database was searched using "PubMed" without restriction to language. The search generated 266 references on 15 November 2005. Most studies were in vitro in nature and of these, most involved studies in the rat aorta. Many of the natural products evoked vasodilatation through an endothelium-dependent mechanism. The vasodilatation was attenuated or abolished by a nitric oxide synthase inhibitor and, in some of these studies, by an inhibitor of guanylate cyclase. A few studies reported a cyclooxygenase component, but most found no effect of the cyclooxygenase inhibitor, indomethacin. The vasorelaxation evoked by several natural products was attenuated by various potassium channel blocking agents, suggesting that some natural products exerted their effect either directly or indirectly through activation of potassium channels. Finally, a significant number of natural products evoked vasodilatation either through blockade of calcium channels or by inhibiting the release of calcium from intracellular stores. Many natural products evoked vasodilatation through multiple mechanisms. The information in this review on mechanisms of action should facilitate good clinical practice by increasing the predictive capabilities of the practitioner, notably the ability to predict adverse effects and interactions among medications. The knowledge should also help to provide leads to the ultimate goal of developing new therapeutic medications.

Aspirin restores normal baroreflex function in hypercholesterolemic rats by its antioxidative action

Besides its well-known effects on platelet aggregation, aspirin has been suggested to be an antioxidant and is also known to improve the lipid profile. In the present study we tested the hypothesis that aspirin by its antioxidant effect, improves haemodynamic profile and baroreflex sensitivity in rat model of hypercholesterolemia. Hypercholesterolemia was induced in Wistar rats by feeding 1% cholesterol rich diet for 10 weeks. Lipid profile, lipid peroxidation and reduced glutathione were estimated in serum. Haemodynamic changes and baroreflex were measured in anaesthetized rats. Hypercholesterolemic rats showed significant increase in total cholesterol, low-density lipoprotein-cholesterol (LDL-C), very low-density lipoprotein-cholesterol (VLDL-C) and atherogenic index and significant decrease in high-density lipoprotein-cholesterol (HDL-C). Significant rise in blood pressure, heart rate and attenuation of baroreflex sensitivity were also found in hypercholesterolemic rat. Aspirin in the dose of 100 mg/kg showed significant decrease in total cholesterol, LDL-C, VLDL-C and atherogenic index and significant increase in HDL-C. Aspirin treatment prevented the rise in blood pressure, heart rate and significantly improved baroreflex sensitivity in hypercholesterolemic rats. Hypercholesterolemic rats showed free radical generation, evident by a significant increase in serum lipid peroxidation and significant reduction in serum reduced glutathione content. Aspirin treatment significantly decreased lipid peroxidation and significantly increased reduced glutathione content. We have demonstrated that aspirin improves baroreflex response and prevents the rise in blood pressure and heart rate possibly by reducing sympathetic activity due to its antioxidant effect in experimentally induced hypercholesterolemic rats.

Quantitative determination of eight components in rhizome (Jianghuang) and tuberous root (Yujin) of Curcuma longa using pressurized liquid extraction and gas chromatography–mass spectrometry

Curcuma longa (Zingiberaceae) is a native plant of southern Asia and is cultivated extensively throughout the warmer parts of the world. Jianghuang and Yujin are rhizome and tuberous root of C. longa, respectively, which were traditionally used as two Chinese medicines. In this paper, pressurized liquid extraction (PLE) and gas chromatography-mass spectrometry (GC-MS) were developed for quantitative determination/estimation of eight characteristic compounds including beta-caryophyllene, ar-curcumene, zingiberene, beta-bisabolene, beta-sesquiphellandrenendrene, ar-turmerone, alpha-turmerone and beta-turmerone in Jianghuang and Yujin. A HP-5MS capillary column (30 m x 0.25 mm i.d.) coated with 0.25 microm film 5% phenyl methyl siloxane was used for separation and selected ion monitoring (SIM) method was used for quantitation. Hierarchical cluster analysis based on characteristics of eight identified peaks in GC-MS profiles showed that 10 samples were divided into two main clusters, Jianghuang and Yujin, respectively. Four components such as ar-curcumene, ar-turmerone, alpha-turmerone and beta-turmerone were optimized as markers for quality control of rhizome (Jianghuang) and tuberous root (Yujin), which are two traditional Chinese medicines, from Curcuma longa.

Puerarin decreases serum total cholesterol and enhances thoracic aorta endothelial nitric oxide synthase expression in diet-induced hypercholesterolemic rats

Hypercholesterolemia is a dominant risk factor for the development and progression of atherosclerosis and cardiovascular diseases. Natural compounds have been proved to be useful in lowering serum cholesterol to slow down the progression of cardiovascular diseases. Pueraria lobata is employed clinically to treat cardiovascular diseases in China. In the present study, the atheroscleroprotective potential of the herb's major active compound, puerarin, was investigated by monitoring serum lipid profile and major enzyme expressions on cholesterol homeostasis in Sprague-Dawley rats fed with control diet, hypercholesterolmic diet or hypercholesterolmic diet plus administration of puerarin (300 mg/kg/day, p.o.) for 4 weeks. Puerarin markedly attenuated the increased total cholesterol induced by hypercholesterolmic diet in both serum and liver. It caused a significant reduction in the atherogenic index. Expression of mRNA for hepatic 7alpha-hydroxylase (CYP7A1) was significantly enhanced but not for those of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) and lanosterol 14alpha-demethylase (CYP51). To further explore the atheroscleroprotective potential of puerarin, acetylcholine induced endothelium-dependent vasorelaxation and endothelial nitric oxide synthase (eNOS) expression on isolated thoracic aortas were analyzed. Animals administered with puerarin suppressed the hypercholesterolemic diet induced impairment of eNOS expression, whereas there was no significant difference in the endothelium-dependent vasorelaxation among various groups of animals. These data indicated that puerarin reduced the atherogenic properties of dietary cholesterol in rats. Its hypocholesterolemic function may be due to the promotion of cholesterol and bile acids excretion in liver. Whether puerarin targets directly on cholesterol homeostasis or both cholesterol homeostasis and endothelial function remains to be determined.

Astrocyte-endothelial interactions at the blood-brain barrier

The blood-brain barrier, which is formed by the endothelial cells that line cerebral microvessels, has an important role in maintaining a precisely regulated microenvironment for reliable neuronal signalling. At present, there is great interest in the association of brain microvessels, astrocytes and neurons to form functional 'neurovascular units', and recent studies have highlighted the importance of brain endothelial cells in this modular organization. Here, we explore specific interactions between the brain endothelium, astrocytes and neurons that may regulate blood-brain barrier function. An understanding of how these interactions are disturbed in pathological conditions could lead to the development of new protective and restorative therapies.