Suppression of diet-induced hypercholesterolemia by turtle jelly, a traditional chinese functional food, in rats

Low Dose of Emodin Inhibits Hypercholesterolemia in a Rat Model of High Cholesterol

BACKGROUND Emodin has been widely used in traditional Chinese medicine, but few studies have tried to understand the mechanism of its anti-hypercholesterolemic effect. MATERIAL AND METHODS To delineate the underlying pathways, high-cholesterol diet (HCD)-fed Sprague-Dawley rats were orally administrated emodin or the lipid-lowering medicine simvastatin. Emodin was administered at 10, 30, or 100 mg/kg, while simvastatin was administered at 10 mg/kg. Parameters measured included lipid profiles (serum total cholesterol, triglycerides, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol, aorta endothelium-dependent vasorelaxation in response to acetylcholine, and nitric oxide (NO) production. RT-qPCR and western blotting were performed to evaluate aortic endothelial nitric oxide synthase (eNOS), phosphorylated eNOS (p-eNOS), and hepatic LDL receptor (LDLR). Indices of liver and serum oxidation were also measured. RESULTS The atherogenic index was increased by the HCD but significantly reduced in all treatment groups. The HCD-fed experimental group treated with emodin at 10 mg/kg had significantly lower serum total-C and LDL-C and improved aorta vasorelaxation and enhanced NO production. Also, emodin significantly attenuated the lipid profiles and restored endothelial function, as reflected by upregulated expression of hepatic LDLR and p-eNOS, respectively. Furthermore, emodin at 10 mg/kg significantly enhanced superoxide dismutase activity, lowered the malondialdehyde level in both liver and serum, and enhanced catalase activity in serum. CONCLUSIONS The ability of emodin to inhibit hypercholesterolemia in HCD-fed rats was associated with lower serum total-C and LDL-C, restoration of aortic endothelial function, and improved antioxidant capacity. Low-dose emodin showed better protection of aortic endothelium and better antioxidant activity than did higher doses.

Naringin Reverses High-Cholesterol Diet-Induced Vascular Dysfunction and Oxidative Stress in Rats via Regulating LOX-1 and NADPH Oxidase Subunit Expression

Hypercholesterolaemia is associated with oxidative stress and endothelial dysfunction and leads to the development of atherosclerosis. Naringin exhibits cardiovascular protective and antioxidant properties. Therefore, the aim of this study was to assess the effect of naringin administration on vascular oxidative stress and endothelial dysfunction in hypercholesterolaemic rats and to elucidate its underlying mechanism. Sprague Dawley rats were fed a diet with 1.5% cholesterol (HCD) for 8 weeks to induce hypercholesterolaemia. Naringin (100 mg/kg body weight) was orally administrated to rats during the last 4 weeks of the diet treatment. After 8 weeks, the thoracic aorta was isolated to determine vascular function and nitric oxide (NO) levels. The aortic superoxide anion (O₂⁻) level was detected using dihydroethidium (DHE) fluorescence staining. Protein expression of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits, and inducible nitric oxide synthase (iNOS), as well as oxidative damage markers, was also evaluated in aortae. Naringin treatment of hypercholesterolaemic rats enhanced aortic NO levels, restored endothelium-dependent responses to acetylcholine (ACh), and reduced aortic O₂⁻ levels. Furthermore, naringin treatment decreased LOX-1, NADPH oxidase subunits (p47^phox, Nox2, and Nox4), and iNOS as well as oxidative damage markers (3-nitrotyrosine (3-NT) and 4-hydroxynonenal (4-HNE)) expression in aortic tissues from hypercholesterolaemic rats. These results demonstrate that naringin treatment improves endothelium dysfunction in hypercholesterolaemic rats, at least partially by decreasing oxidative stress via downregulation of LOX-1 and NADPH oxidase.

Ginsenoside Rg1 attenuates liver injury induced by D-galactose in mice

The present study investigated the effect and underlying mechanisms of ginsenoside Rg1 (Rg1) in attenuating subacute liver injury induced by D-galactose (D-gal) in mice. Specific Pathogen Free (SPF) male C57BL/6J mice were randomly divided into 3 groups: i) D-gal-administration group (D-gal group), where the mice were intraperitoneally administrated with D-gal (120 mg/kg/day for 42 days); ii) D-gal + Rg1 group where the mice were treated with 120 mg/kg/day D-gal for 42 days and with Rg1 at a dose of 20 mg/kg/day for 35 days. The first dose of Rg1 was administered on the 8th day of treatment with D-gal; and iii) the normal control group, where the mice were injected with an equal volume of saline for 42 days. The day following the final injections in all groups, peripheral blood was collected and serum was prepared to measure the contents of aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (TBiL), advanced glycation end products (AGEs) and 8-hydroxy-2 deoxyguanosine (8-OH-dG). Liver tissue homogenates were prepared to measure the contents of malondialdehyde (MDA) and glutathione (GSH), and the activities of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD). Paraffin section were prepared to observe the microscopic structure of the liver. Transmission electron microscopy was used to observe the ultrastructure of hepatocytes. Frozen section were prepared and stained with senescence-associated β-galactosidase to detect the relative optical density value of senescence-associated markers. Compared with the D-gal group, the contents of AST, ALT, TBiL, AGEs and MDA significantly decreased in the D-gal + Rg1 group, while the activities of SOD and GSH-Px markedly increased, and liver injury and degenerative alterations of hepatocytes were reduced. Administration of Rg1 induced a protective effect on D-gal-induced liver injury in mice by inhibiting the oxidative stress, reducing DNA damage and decreasing the AGE content.

Rapid discrimination of raw and sulfur-fumigated Smilax glabra based on chemical profiles by UHPLC-QTOF-MS/MS coupled with multivariate statistical analysis

Smilax glabra (SG) is commonly used as a traditional edible herb in eastern Asia. Recently, sulfur-fumigation has been frequently used in order to obtain better color and a longer storage lifetime. However, the chemical alterations caused by this process remain unknown. The aim of this research was to explore potential chemical differences between non-fumigated and sulfur-fumigated SG samples. A novel approach was developed by using ultra-high-performance liquid chromatography-quadrupole/time-of-flight mass spectrometry (UHPLC-QTOF-MS/MS) with principal component analysis (PCA) and orthogonal partial squared discriminant analysis (OPLS-DA). Fifty-eight compounds were unambiguously characterized or tentatively identified in the chemical profiles for the first time. Six newly generated sulfur-containing compounds, namely glucosyringic acid sulfate, 5-O-caffeoylshikimic acid sulfite, 3-O-caffeoylshikimic acid sulfite, 5-O-caffeoylshikimic acid sulfate, 3-O-caffeoylshikimic acid sulfate and astilbin sulfate, were screened out to be the most characteristic markers for distinguishing non-fumigated and sulfur-fumigated SG. This newly proposed approach can not only be applied for exploring chemical markers but can also be used to investigate the chemical transformation mechanism associated with sulfur for other edible herbs.

THE MECHANISM OF ALPHA LIPOIC ACID ON REDUCING THE MDA LEVEL AND MCP-1 EXPRESSION IN ENDOTHELIAL DYSFUNCTION OF HYPERCHOLESTEROLEMIA RAT (Rattus norvegicus) MODEL

Endothelial dysfunction is an initial condition of atherosclerosis and other vascular diseases where one of the risk factors is hypercholesterolemia. Blood cholesterol levels is associated with an increase in the production of reactive oxygen species (ROS). The increasing of ROS production can cause increased oxidative stress which in turn resulting in endothelial dysfunction. Alpha lipoic acid (ALA) is one of the antioxidant compound that has been developed and studied. In this study we found that the use of ALA in Rattus norvegicus rats signifficantly lower the total cholesterol levels at dose 60 mg/kgBW (p=0.020). ALA also inhibit the expression of Monocyte Chemoattractant Protein-1 (MCP-1) at dose 60 mg/kgBW (p=0.044) and reduces the formation of Malondialdehyde (MDA) at dose 120 mg/kgBW (p=0.009), which is the initial stage of the atherogenic development and prognosis of events, thus, ALA can reduce the risk of further damage to the endothelium.

POSSIBLE HYPOCHOLESTEROLEMIC EFFECT OF GINGER AND ROSEMARY OILS IN RATS

BACKGROUND

Hypercholesterolemia is a major risk factor for development of atherosclerosis. The present study was conducted to evaluate the potential effect of ginger oil alone or combined with rosemary oil as hypocholesterolemic agent in rats fed high fat diet.

MATERIALS AND METHODS

Healthy female albino rats (n=80) weighting about (150-180 g) were included in this study divided into two equal groups; Group (I): were fed on the basal diet. Group (I) were divided into 4 subgroups each 10: Group (Ia): negative control. Group (Ib): Rats received i.p 2.5 g/Kg b.w of ginger oil. Group (Ic): rats received i.p 2.5 g/Kg b.w of rosemary oil. Group (Id): Rats received i.p 5 g/Kg b.w mixture of ginger oil and rosemary oil (1:1). The second main groups; Group (II): high fat diet (HFD) were fed on the basal diet plus cholesterol (1%), bile salt (0.25%) and animal fat (15%) to induce hypercholesterolemia for six weeks. Group (II) was divided into 4subgroups: Group (IIa): HFD. Group (IIb): HFD were treated with i.p 2.5 g/Kg b.w ginger oil. Group (IIc): (n=10) HFD were treated with i.p 2.5 g/Kg b.w rosemary oil. Group (IId): (n=10) HFD were treated with i.p 5 g/Kg b.w mixture of oils.

RESULTS

It was found that HFD rats showed a significant elevation in glucose, total cholesterol, triglyceride, GOT, GPT, alkaline phosphatase and a reduction in serum HDL-c compared with negative control. Treatment with ginger oil, rosemary oil and their mixture modulated the elevation of these parameters. Histopathological examination of the liver tissue of HFD rats showed a lipid deposition and macrophage infiltration and stenosis of hepatic vein. Treatment with mixture oils preserves normal structure of liver.

CONCLUSION

It was concluded that, hypocholesterolemic effect was related to the active oil content as Rosemary oil contain - α-pinene, Camphor, cineole, borneol and Ginger oil contain Linalool, Terpineol, Borneol, Eucalyptol.

Hypocholesterolemic effect of quercetin-rich onion peel extract in C57BL/6J mice fed with high cholesterol diet

Onion peel (OP) extract is known as a rich source of flavonoids, mainly quercetin. We hypothesized that OP has hypocholesterolemic effects. To investigate the effect of OP, C57BL/6J mice were divided into 4 dietary groups (n=10); normal diet (ND); high cholesterol diet (HC); and high cholesterol diet with 100 or 200 mg OP extract (OP-100 or OP-200, respectively) per kg of body weight. After 12 weeks, lower values of liver weight, serum total cholesterol levels, LDL cholesterol, atherogenic index, cardiac risk factor, hepatic triacylglycerol, and total cholesterol, and higher fecal cholesterol levels were observed in the OP-200 than in the HC group. The hepatic mRNA expression levels of low-density lipoprotein receptors (LDL-R) and cholesterol 7-alpha-monooxygenase (CYP7A1) were high in the OP-200 compared to the HC group. These observations suggest that OP promoted lowering of serum and hepatic cholesterol in mice primarily via fecal excretion.

In Vivo Antioxidant and Hypolipidemic Effects of Fermented Mung Bean on Hypercholesterolemic Mice

Legumes have previously been reported with hypolipidemic effect caused by the presence of flavonoid. This study was carried out to evaluate the antioxidant and hypolipidemic effects of fermented mung bean on hypercholesterolemic mice. Blood from all mice was collected and subjected to serum lipid and liver profiles biochemical analysis and quantitative RT-PCR for atherosclerosis related gene expressions. Besides, livers were collected for antioxidant assays and histopathology evaluation. Fermented mung bean was found to reduce the level of serum lipid and liver enzyme profiles of hypercholesterolemic mice. Furthermore, liver antioxidant and nitric oxide levels were also significantly restored by fermented mung bean in a dosage dependent manner. The gene expression study indicated that Apoe and Bcl2a1a were upregulated while Npy and Vwf expressions were downregulated after the treatment. The effects of fermented mung bean were greater than nonfermented mung bean. These results indicated that fermented mung bean possessed antioxidants that lead to its hypolipidemic effect on hypercholesterolemic mice.

Berberine decreases cholesterol levels in rats through multiple mechanisms, including inhibition of cholesterol absorption

OBJECTIVE

The objective was to determine the mechanisms of action of berberine (BBR) on cholesterol homeostasis using in vivo and in vitro models.

METHODS

Male Sprague-Dawley rats were fed the AIN-93G diet (normal control) or modified AIN-93G diet containing 28% fat, 2% cholesterol and 0.5% cholic acid with treatment of 0 (atherogenic control), 50, 100, and 150 mg/kg·d of BBR, respectively by gavaging in water for 8 weeks. Cholesterol absorption rate was measured with the dual stable isotope ratio method, and plasma lipids were determined using the enzymatic methods. Gene and protein expressions of Acyl-coenzyme A:cholesterol acyltransferase-2 were analyzed in vivo and in vitro. Cholesterol micellarization, uptake and permeability were determined in vitro.

RESULTS

Rats on the atherogenic diet showed significantly hypercholesterolemic characteristics compared to normal control rats. Treatment with BBR in rats on the atherogenic diet reduced plasma total cholesterol and nonHDL cholesterol levels by 29%-33% and 31%-41%, respectively, with no significant differences being observed among the three doses. The fractional dietary cholesterol absorption rate was decreased by 40%-51%. Rats fed the atherogenic diet showed lower plasma triacylglycerol levels, and no changes were observed after the BBR treatment. BBR interfered with cholesterol micellarization, decreased cholesterol uptake by Caco-2 cells and permeability through Caco-2 monolayer. BBR also inhibited the gene and protein expressions of acyl-coenzyme A cholesterol acyltransferease-2 in the small intestine and Caco-2 cells.

CONCLUSION

BBR lowered blood cholesterol levels at least in part through inhibiting the intestinal absorption and further by interfering with intraluminal cholesterol micellarization and decreasing enterocyte cholesterol uptake and secretion.

A review on the traditional Chinese medicinal herbs and formulae with hypolipidemic effect

Hyperlipidemia, characterized by the abnormal blood lipid profiles, is one of the dominant factors of many chronic diseases such as diabetes, obesity, and cardiovascular diseases (CVD). For the low cost, effectiveness, and fewer side effects, the popularity of using traditional Chinese medicine (TCM) to handle hyperlipidemia is increasing and its role in health care has been recognized by the public at large. Despite the importance of TCM herbs and formulations, there is no comprehensive review summarizing their scientific findings on handling hyperlipidemia. This review summarizes the recent experimental and clinical results of nine representative single Chinese herbs and seven classic TCM formulae that could improve lipid profiles so as to help understand and compare their underlying mechanisms. Most of single herbs and formulae demonstrated the improvement of hyperlipidemic conditions with multiple and diverse mechanisms of actions similar to conventional Western drugs in spite of their mild side effects. Due to increasing popularity of TCM, more extensive, well-designed preclinical and clinical trials on the potential synergistic and adverse side effects of herb-drug interactions as well as their mechanisms are warranted. Hyperlipidemic patients should be warned about the potential risks of herb-drug interactions, particularly those taking anticoagulants and antiplatelet drugs.

A Review of the Pharmacological Effects of the Dried Root of Polygonum cuspidatum (Hu Zhang) and Its Constituents

Traditional Chinese medicine (TCM) has been widely used in China for thousands of years to treat and prevent diseases. TCM has been proven safe and effective, and it is being considered as one of the important types of complementary and alternative medicine and receives increasing attention worldwide. The dried root of Polygonum cuspidatum Sieb. et Zucc. (also known as “Hu Zhang” in Chinese) is one of the medicinal herbs listed in the Pharmacopoeia of the People's Republic of China. Hu Zhang is widely distributed in the world. It can be found in Asia and North America and is used as folk medicine in countries such as Japan and Korea. In China, Hu Zhang is usually used in combination with other TCM herbs. The therapeutic uses of those Hu Zhang-containing TCM prescriptions or formulations are for treating cough, hepatitis, jaundice, amenorrhea, leucorrhea, arthralgia, burns and snake bites. Recent pharmacological and clinical studies have indicated that Hu Zhang has antiviral, antimicrobial, anti-inflammatory, neuroprotective, and cardioprotective functions. This review gives a summary of the reported therapeutic effects of the active compounds and the different extracts of Hu Zhang.