Hypolipidemic Effect and Mechanism of Palmatine from Coptis chinensis in Hamsters Fed High‐Fat diet

Palmatine (PAL) is one of the main alkaloids in Coptis chinensis. The present aim was to investigate the hypolipidemic effect and mechanism of palmatine in hamsters fed with high‐fat diet (HFD). PAL treatment decreased serum total cholesterol (TC), triglyceride (TG), and low‐density lipoprotein cholesterol (LDL‐C) levels, as well as increased fecal excretion of TC and total bile acids (TBA) in hyperlipidemic hamsters. Furthermore, PAL treatment up‐regulated low‐density lipoprotein receptor (LDLR) and cholesterol 7α‐hydroxylase (CYP7A1) mRNA and protein expression and down‐regulated apical sodium‐dependent bile salt transporter (ASBT) mRNA and protein expression. These results demonstrated that PAL as a potential natural cholesterol lowering agent works by up‐regulating LDLR and CYP7A1 mRNA and protein expression, down‐regulating ASBT mRNA and protein expression, as well as enhancing fecal excretion of TC and TBA. The findings in our study suggest that palmatine could be a potential natural agent for treating hyperlipidemia. Copyright © 2015 John Wiley & Sons, Ltd.     

Hypolipidemic activity and mechanism of purified herbal extract of Salvia miltiorrhiza in hyperlipidemic rats

AIM OF THE STUDY: The study aimed at evaluating the hypolipidemic effects of Purified Salvia miltiorrhiza extract (PSME) and investigating the potential molecular mechanisms by which PSME modulated lipid profiles in hyperlipidemic rats. MATERIALS AND METHODS: Sprague-Dawley male rats on a high-fat/high-cholesterol diet were treated orally with PSME, GW3965 (a selective liver X receptor agonist) or vehicle alone. Gene expression analysis and transactivation assays were used to clarify the molecular mechanisms of action of PSME. RESULTS: The concentrations of plasma total cholesterol, low-density lipoprotein cholesterol (LDL-cholesterol) and triglycerides in rats treated with PSME at 150mgkgday(-1) were significantly decreased (P<0.01), accompanied with significantly decreased concentrations of liver total cholesterol and triglycerides (P<0.01). In both drug-treated rats, the concentration of high-density lipoprotein cholesterol (HDL-cholesterol) was significantly elevated (P<0.01). Intriguingly, short heterodimer partner (SHP) mRNA level was significantly higher in PSME-treated rats (P<0.01), accompanied with the significantly decreased mRNA level of sterol regulatory element binding protein 1c (SREBP1c) (P<0.01), which contributed to the decreases of liver and plasma triglycerides through a farnesoid X receptor-SHP-SREBP1c pathway. ATP-binding Cassette Transporter B11 (ABCB11) and murine Mdr2 P-glycoprotein (also known as ABCB4) were significantly induced by PSME, which were responsible for biliary cholesterol solubility by proper biliary secretion of bile salts and phospholipids. The transactivation assays were used to identify PSME as a farnesoid X receptor/liver X receptor alpha coagonist. CONCLUSION: These results indicated that PSME as a farnesoid X receptor/liver X receptor alpha coagonist largely improved the lipid profiles in the hyperlipidemic rats.     

Hypolipidemic activity and mechanisms of the total phenylpropanoid glycosides from Ligustrum robustum (Roxb.) Blume by AMPK‐SREBP‐1c pathway in hamsters fed a high‐fat diet

The aim of this study was to evaluate the hypolipidemic effect and mechanisms of total phenylpropanoid glycosides extracted from Ligustrum robustum (Roxb.) Blume (LRTPG) in hamsters fed a high‐fat diet and to discover bioactive components in HepG2 cell model induced by oleic acid. LRTPG of high (1.2 g/kg), medium (0.6 g/kg), and low (0.3 g/kg) doses was administrated daily for 21 consecutive days in hamsters. We found that in hamsters fed a high‐fat diet, LRTPG effectively reduced the concentrations of plasma triglycerides (TG), free fatty acid, total cholesterol, low‐density lipoprotein cholesterol, and hepatic TG and total cholesterol. And the compounds acteoside, ligupurpuroside A, ligupurpuroside C, and ligupurpuroside D significantly inhibited lipid accumulation in HepG2 cell at the concentration of 50 μmol/L. Mechanism research demonstrated that LRTPG increased the levels of phospho–AMP‐activated protein kinase and phospho‐sterol regulatory element binding protein‐1c in liver, further to suppress the downstream lipogenic genes as stearoyl‐CoA desaturase 1, glycerol‐3‐phosphate acyltransferase, 1‐acylglycerol‐3‐phosphate O‐acyltransferase 2, and diacylglycerol acyltransferase 2. In addition, LRTPG increased the hydrolysis of circulating TG by up‐regulating lipoprotein lipase activities. These results indicate that LRTPG prevents hyperlipidemia via activation of hepatic AMP‐activated protein kinase‐sterol regulatory element binding protein‐1c pathway.     

Bile acid‐binding activity of young persimmon (Diospyros kaki) fruit and its hypolipidemic effect in mice

The hypolipidemic effects and bile acid‐binding properties of young persimmon (Diospyros kaki) fruit were examined. In an animal experiment, male C57BL/6.Cr mice (n = 5) were fed an AIN‐76‐modified high fat diet supplemented with 2% or 5% (w/w) dried young persimmon fruit (YP) for 10 weeks. The intake of YP significantly enhanced fecal bile acid excretion and lowered the concentration of hepatic lipids and plasma cholesterol. Analysis of gene expression in liver tissue showed that 2% or 5% YP up‐regulated the expression of the sterol regulatory element‐binding protein‐2 gene. In the 5% group, there were increased expressions of the genes for cholesterol 7α‐hydroxylase and the low‐density lipoprotein receptor. Next, the bile acid‐binding ability of YP was analysed in vitro using cholic acid (CA). In 100–2000 µM CA solutions, 1% (w/v) YP adsorbed approximately 60% of CA, while dried mature persimmon fruit adsorbed approximately 20% of CA. The positive control, cholestyramine, adsorbed approximately 80% of CA in the 100–2000 µM CA solutions. A crude tannin extract from YP, which contained 54.7% condensed tannins, adsorbed approximately 78% of CA in the 2000 µM CA solutions. These results suggest that the ability of YP to bind bile acid contributes to its hypolipidemic effect in mice. Copyright © 2009 John Wiley & Sons, Ltd.     

Effects of Sinensetin on Lipid Metabolism in Mature 3T3‐L1 Adipocytes

Sinensetin is a rare polymethoxylated flavone found in certain citrus fruits. In this study, we investigated the effects of sinensetin on lipid metabolism in mature 3T3‐L1 adipocytes. Sinensetin decreased the expression of sterol regulatory element‐binding protein 1c (SREBP1c), suggesting its antiadipogeneic property via downreguation of SREBP1c. Also, sinensetin increased the phosphorylation of protein kinase A and hormone‐sensitive lipase, indicating its lipolytic property via a cAMP‐mediated signaling pathway. Moreover, sinensetin inhibited insulin‐stimulated glucose uptake by decreasing the phosphorylation of insulin receptor substrate and Akt. Furthermore, sinensetin increased the phosphorylation of AMP‐activated protein kinase (AMPK) and acetyl‐CoA carboxylase. It also upregulated mRNA expression of carnitine palmitoyltransferase‐1a, suggesting that sinensetin enhances fatty acid β‐oxidation through the AMPK pathway. Taken together, these results suggest that sinensetin may have potential as a natural agent for prevention/improvement of obesity. Copyright © 2012 John Wiley & Sons, Ltd.     

Hovenia Dulcis Extract Reduces Lipid Accumulation in Oleic Acid‐Induced Steatosis of Hep G2 Cells via Activation of AMPK and PPARα/CPT‐1 Pathway and in Acute Hyperlipidemia Mouse Model

Hovenia dulcis Thunb. (HDT) was known to have anti‐fatigue, anti‐diabetes, neuroprotective, and hepatoprotective effects. In the present study, the anti‐fatty liver mechanism of HDT was elucidated in oleic acid (OA)‐treated Hep G2 cells and acute hyperlipidemia mouse model using Triton WR‐1339. Here, HDT activated p‐AMP‐activated protein kinase (p‐AMPK), proliferator activated receptor‐α, carnitine palmitoyltransferase and also inhibited the expression of lipogenesis and cholesterol synthesis proteins, such as 3‐hydroxy‐3‐methylglutaryl‐CoA reductase, sterol regulatory element binding protein‐1c, SREBP‐2, and fatty acid synthase in OA‐treated Hep G2 cells. Conversely, AMPK inhibitor compound C blocked the anti‐fatty liver effect of HDT to induce AMPK phosphorylation and decrease 3‐hydroxy‐3‐methylglutaryl‐CoA reductase and lipid accumulation by oil red O staining in OA‐treated Hep G2 cells. Additionally, HDT pretreatment protected against the increase of serum total cholesterol, triglyceride, low‐density lipoprotein cholesterol and phospholipid in an acute hyperlipidemia mouse model with enhancement of glutathione reductase, glutathione peroxidase, superoxide dismutase, and catalase activities. Taken together, HDT inhibits OA‐induced hepatic lipid accumulation via activation of AMPK and proliferator activated receptor‐α/carnitine palmitoyltransferase signaling and enhancement of antioxidant activity as a potent candidate for nonalcoholic fatty liver disease and hyperlipidemia. Copyright © 2016 John Wiley & Sons, Ltd.     

A new TCM formula FTZ lowers serum cholesterol by regulating HMG-CoA reductase and CYP7A1 in hyperlipidemic rats

Ethnopharmacological relevance

Based on a theory of Chinese Medicine, Regulating Gan (liver) to lower lipids that is in brief to regulate the lipid metabolic related factors in the liver will improve serum lipid profile, we have developed Fufang Zhenzhu Tiao Zhi (FTZ) which includes eight herbs that are quality assured. FTZ has been developed with the potential to correct abnormal lipid metabolism. This Chinese herbal medicine has been prescribed for 20 years, which has been issued patent and clinically proven for use in the treatment of dyslipidemia.

Aim of the study

To investigate the cholesterol-lowering effect and the mode of action of FTZ extract on high lipid diet induced hyperlipidemic rats.

Materials and methods

The FTZ was prepared by alcohol and water extraction of eight herbs that have been quality-controlled according to the protocol. The cholesterol-lowering effect of FTZ was evaluated on SD rats fed with high-lipid diet. RT-PCR and western blot were used to analyze the gene expression of cholesterol metabolism-related enzymes including HMG-CoA reductase and cholesterol 7α-hydroxylase (CYP7A1) in the livers of the rats. The activity of HMG-CoA reductase and CYP7A1 were assessed by colorimetrical method and by quantification of the cholesterol metabolite of CYP7A1 using HPLC analysis respectively.

Results and conclusions

FTZ significantly decreased the levels of serum total cholesterol (TC), triglycerides (TG) and low-density lipoprotein cholesterol (LDL-C), whilst elevated the serum high-density lipoprotein cholesterol (HDL-C) and decreased serum atherogenic index (A.I.) values in high lipid diet induced hyperlipidemic rats. Furthermore, FTZ showed significant antihyperlipidemic effect by at least three pathways in the high lipid diet induced hyperlipidemic rats: (1) upregulating the gene expression and activity of CYP7A1 which promotes the conversion of cholesterol into bile acid; (2) downregulating the gene expression and activity of HMG-CoA reductase to reduce de novo synthesis of cholesterol; (3) increasing the cholesterol excretion from feces. In these three pathways, HMG-CoA reductase and CYP7A1 are two pivotal enzymes in lipid cholesterol metabolism and are expressed mainly in hepatic cells, which support our new TCM treatment strategy: Modulating Liver to Treat Hyperlipemia.     

Reduction of lipid accumulation in HepG2 cells by luteolin is associated with activation of AMPK and mitigation of oxidative stress

The present study was carried out to investigate the lipid-lowering effect of luteolin by using a cell model of steatosis induced by palmitate. Incubation of HepG2 cells with palmitate markedly increased lipid accumulation (Oil Red O staining), the genes involved in lipogenesis, including fatty acid synthase (FAS) and its upstream regulator sterol regulatory element binding protein 1c (SREBP-1c), and reactive oxygen species (ROS) production. Luteolin enhanced the phosphorylation of AMP-activated protein kinase α (AMPKα) and its primary downstream targeting enzyme, acetyl-CoA carboxylase (ACC), up-regulated gene expression of carnitine palmitoyl transferase 1 (CPT-1), which is the rate-limiting enzyme in mitochondrial fatty acid β-oxidation, and down-regulated SREBP-1c and FAS mRNA levels in the absence and presence of palmitate. In addition, luteolin significantly decreased ROS production and ameliorated lipid accumulation in HepG2 cells caused by palmitate. Furthermore, intracellular triglyceride (TG) measurement indicated that the luteolin-mediated reduction of enhanced TG caused by palmitate was blocked by pretreatment with the AMPK inhibitor, compound C. The results suggested that the lipid-lowering effect of luteolin might be partially mediated by the up-regulation of CPT-1 and down-regulation of SREBP-1c and FAS gene expression, possibly by activation of the AMPK signaling pathway, and partially might be through its antioxidative actions.     

Regulation of obesity and lipid disorders by extracts from Angelica acutiloba root in high-fat diet-induced obese rats

The aim of this study was to investigate the antiobesity and antihyperlipidemic effects of Angelica acutiloba root (Japanese Dong Quai). High‐fat diet (HFD)‐induced obese rats were treated orally with the polyphenolic‐rich extract of Angelica acutiloba root (AARE) once daily for 8 weeks. The AARE (300 mg/kg per day) supplementation significantly lowered body weight gain, visceral fat‐pad weights and plasma lipid levels, as well as the coronary artery risk index and the atherogenic index of HFD‐fed rats. The AARE caused dose related reductions in the hepatic triglyceride and cholesterol contents, as well as lowered hepatic lipid droplet accumulation and epididymal adipocyte size in the HFD‐fed rats. The AARE reversed the HFD‐induced down‐regulation of the hepatic peroxisome proliferator activated receptor‐α (PPARα). The HFD‐induced decreases of the hepatic protein level of acyl‐CoA oxidase (ACO), and the cytochrome P450 isoform 4A1 (CYP4A1) was up‐regulated by AARE. The elevated expressions of hepatic sterol regulatory element binding proteins (SREBPs) of HFD‐fed rats were lowered by AARE. These results suggest that AARE attenuated visceral fat accumulation and improved hyperlipidemia in HFD‐induced obesity by increasing lipid metabolism through the down‐regulation of SREBPs and enhanced the expression of ACO and CYP4A1 in the liver, which was likely mediated by up‐regulation of the expression of hepatic PPARα. Copyright © 2011 John Wiley & Sons, Ltd.     

Hypolipidemic activity of aqueous extract of Withania coagulans Dunal in albino rats

Administration of an aqueous extract of fruits of Withania coagulans (1 g/kg; p.o.) to high fat diet induced hyperlipidemic rats for 7 weeks, significantly reduced elevated serum cholesterol, triglycerides and lipoprotein levels. This drug also showed hypolipidemic activity in triton induced hypercholesterolemia. The histopathological examination of liver tissues of treated hyperlipidemic rats showed comparatively lesser degenerative changes compared with hyperlipidemic controls. The hypolipidemic effect of W. coagulans fruits was found to be comparable to that of an Ayurvedic product containing Commiphora mukkul.     

Hypoglycemic and Hypolipidemic Effects of Lycium barbarum Polysaccharide in Diabetic Rats

Objective To study the antidiabetic effects and the underlying molecular mechanisms of Lycium barbarum polysaccharide(LBP) and its DEAE cellulose elution fraction LBP-IV in diabetic rats induced by high fat diet(HFD) and streptozotocin(STZ). Methods After ig administration of LBP-IV [50, 100, and 200 mg/(kg·d)] and LBP [100 mg/(kg·d)] once daily for consecutive 4 weeks to diabetic rats, the glucose and lipids in blood, m RNA expression of phosphoenolpyruvate carboxykinase(PEPCK), sterol regulatory element binding-protein-1c(SREBP-1c), and fatty acid synthase(FAS) in liver were determined. Results Ig administration of LBP and LBP-IV significantly decreased the levels of blood glucose, Hb A1 c, TC, TG, and LDL-C, as well as the hepatic m RNA expression of PEPCK, SREBP-1c, and FAS, whereas significantly increased the oral glucose tolerance of diabetic rats. Conclusion The findings suggest that the antidiabetic effects of LBP and LBP-IV are associated with the decreased hepatic m RNA expression of PEPCK, SREBP-1c, and FAS in HFD-STZ induced diabetic rats.     

6-姜烯酚通过抑制SCD1 表达改善db/db 小鼠肝脏脂肪变性的研究

目的探讨6-姜烯酚对db/db小鼠肝脏脂质代谢的影响及机制。方法将24只db/db小鼠随机分为模型组、6-姜烯酚低剂量组(10 mg·kg^-1)和6-姜烯酚高剂量组(40 mg·kg^-1),每组8只,雌雄各半;另取8只BKS小鼠(雌雄各半)作为正常对照组;灌胃给药,每日1次,连续21 d。采用酶法检测肝脏组织甘油三酯(TG)含量;采用油红O染色法检测肝脏组织脂质沉积情况;采用实时荧光定量聚合酶链式反应(qPCR)法检测碳水化合物反应元件结合蛋白(ChREBP)、固醇调节元件结合蛋白-1c(SREBP-1c)、脂肪酸合酶(FAS)、乙酰辅酶A羧化酶(ACC)、二酰基甘油酰基转移酶2(DGAT2)、硬脂酰辅酶A去饱和酶1(SCD1)、酰基辅酶A氧化酶(ACOX)及肉碱棕榈酰基转移酶1a(CPT1a)的mRNA表达;采用Western Blot法和免疫荧光染色法检测肝脏组织SCD1蛋白的表达情况。结果与正常对照组比较,模型组小鼠肝脏组织的TG含量和油红O染色面积以及SREBP-1c、ACC、FAS、DGAT2、SCD1 mRNA表达显著上调(P<0.05,P<0.01),ACOX、CPT1a mRNA表达显著下调(P<0.05)。与模型组比较,6-姜烯酚高剂量组的小鼠肝脏组织TG含量和油红O染色面积明显减少(P<0.01),SCD1在mRNA水平和蛋白水平的表达均显著下调(P<0.05,P<0.01),与免疫荧光染色法检测结果一致。结论6-姜烯酚能够改善db/db小鼠的肝脏脂质沉积,其机制可能与下调SCD1的表达有关。     

交泰丸组分配伍改善小鼠胰岛素瘤B细胞脂质沉积的机制研究

目的：研究交泰丸中主要活性成分小檗碱（BBR）、肉桂酸（CA）及其配伍（BBR/CA）对软脂酸（PA）诱导的NIT-1胰岛B细胞内脂质沉积的影响。方法：将细胞在PA的培养基中培养24 h,建立高脂诱导的细胞内脂肪沉积模型。分为模型组、BBR组、CA组、BBR/CA组、二甲双胍（Met）组,分别给予相应药物干预,另设对照组。油红O染色法评估细胞内脂肪沉积情况;酶法检测细胞内三酰甘油（TG）含量;使用Western Blotting和实时荧光定量PCR（RT-PCR）法检测细胞腺苷酸活化蛋白激酶（AMPK）及其下游脂肪生成和脂肪酸氧化基因的表达水平,包括脂肪酸合成酶（FAS）、乙酰辅酶A羧化酶（ACC）、磷酸化乙酰辅酶A羧化酶（p-ACC）、肉碱酰转移酶-1（CPT-1）、固醇调节元件结合蛋白（SREBP-1c）。结果：PA诱导使NIT-1胰岛B细胞中脂肪沉积明显增加,TG含量显著升高,AMPK蛋白及其下游靶标（如p-ACC、CPT-1等）表达显著降低。同时,AMPK下游脂肪生成基因包括SREBP-1c mRNA、FAS和ACC蛋白表达显著增加。BBR单药和BBR/CA配伍处理优于CA单药,可显著逆转NIT-1胰岛B细胞中上述基因表达水平的变化。结论：在体外,交泰丸活性组分配伍可减少高脂诱导的NIT-1胰岛B细胞内脂肪沉积,其机制可能与减少脂肪合成和增加脂肪氧化有关。     

5‐Hydroxyferulic acid methyl ester isolated from wasabi leaves inhibits 3T3‐L1 adipocyte differentiation

To investigate the compounds present in wasabi leaves (Wasabia japonica Matsumura) that inhibit the adipocyte differentiation, activity‐guided fractionation was performed on these leaves. 5‐Hydroxyferulic acid methyl ester ( 1 : 5‐HFA ester), one of the phenylpropanoids, was isolated from wasabi leaves as a compound that inhibits the adipocyte differentiation. Compound 1 suppressed the intracellular lipid accumulation of 3T3‐L1 cells without significant cytotoxicity. Gene expression analysis revealed that 1 suppressed the mRNA expression of 2 master regulators of adipocyte differentiation, PPARγ and C/EBPα. Furthermore, 1 downregulated the expression of adipogenesis‐related genes, GLUT4, LPL, SREBP‐1c, ACC, and FAS. Protein expression analysis revealed that 1 suppressed PPARγ protein expression. Moreover, to investigate the relationship between the structure and activity of inhibiting the adipocyte differentiation, we synthesized 12 kinds of phenylpropanoid analog. Comparison of the activity among 1 and its analogs suggested that the compound containing the substructure that possess a common functional group at the ortho position such as a catechol group exhibits the activity of inhibiting the adipocyte differentiation. Taken together, our findings suggest that 1 from wasabi leaves inhibits adipocyte differentiation via the downregulation of PPARγ.     

黄芪散有效部位群对胰岛素抵抗HepG2细胞SREBP-1c及其靶基因表达的影响

目的:观察黄芪散有效部位群(HQS)对胰岛素抵抗HepG2细胞固醇调控元件结合蛋白-1c(SREBP-1c)及其靶基因表达的影响,并探讨其可能的作用机制。方法:噻唑蓝(MTT)比色法检测HQS对细胞活性的影响,采用高糖高胰岛素诱导HepG2细胞建立胰岛素抵抗模型,造模同时予以不同浓度HQS进行干预,并以二甲双胍(MET)作为阳性药,另设空白组。采用荧光D-葡萄糖同系物2-脱氧-D-葡萄糖(2-NBDG)检测细胞糖摄取量,测定细胞内甘油三酯(TG),游离脂肪酸(FFA)含量,油红O染色法观察细胞脂质沉积情况,实时荧光定量聚合酶链式反应(Real-time PCR)检测细胞内SREBP-1c,乙酰辅酶A羧化酶1(ACC1),脂肪酸合成酶(FAS),硬脂酰辅酶A去饱和酶(SCD1)基因的表达。结果:依据MTT实验结果,选择25,50,100 mg·L-1分别作为HQS低、中、高质量浓度值(HQS-L,HQS-M,HQS-H),处理时间为24 h。与空白组比较,模型组细胞糖摄取显著减少(P0.01),细胞内TG,FFA含量显著升高(P0.01),胞浆内可见大量红色的小泡性脂滴,SREBP-1c,ACC1,FAS,SCD1 mRNA的表达显著上调(P0.01)。与模型组比较,不同质量浓度HQS均可显著升高细胞糖摄取量(P0.05,P0.01),HQS-H,HQS-M可显著降低细胞中TG,FFA含量(P0.01),减少细胞内脂滴数量,HQS-L亦可降低FFA含量(P0.05),此外,HQS-H可显著下调SREBP-1c,ACC1,FAS,SCD1 mRNA的表达(P0.05,P0.01),HQS-M亦可下调SREBP-1c,FAS,SCD1 mRNA的表达(P0.05),对ACC1 mRNA表达具有一定程度的抑制。结论:HQS可能通过抑制SREBP-1c的表达,减少脂质合成,改善HepG2细胞胰岛素抵抗。