Chlorogenic acid regulates the expression of NPC1L1 and HMGCR through PXR and SREBP2 signaling pathways and their interactions with HSP90 to maintain cholesterol homeostasis.

BACKGROUND: Hypercholesterolemia is widely implicated in the etiology of coronary heart disease, stroke, and dementia. Evidence suggests that chlorogenic acid (CA) reduces the risk of cardiovascular disease. PURPOSE: The current study aims to explore the underlying molecular mechanism of CA in lowering cholesterol based on pregnane X receptor (PXR) and sterol regulatory element-binding protein 2 (SREBP2) regulatory pathways and their interactions with heat shock protein 90 (HSP90). METHODS: A hypercholesterolemic mouse model, HepG2 and Caco2 cell models, metabolomics analysis, and co-immunoprecipitation (COIP) were used to study the mechanism of CA lowering cholesterol. RESULTS: Treatment of the hypercholesterolemic mice with CA for 12 weeks significantly reduced body weight, blood lipid, hepatic lipid accumulation, and increased lipid excretion. The nuclear aggregation of PXR and SREBP2 was inhibited simultaneously. In addition, the expression of downstream target genes, including Niemann-pick C1-like 1 (NPC1L1) and 3­hydroxy-3-methylglutaryl-CoA reductase (HMGCR), was downregulated after CA administration. Furthermore, in HepG2 and Caco2 cell models, CA reduced intracellular cholesterol levels by inhibiting the nuclear translocation of PXR and SREBP2 and the expression of NPC1L1 and HMGCR. SREBP2 interacts with PXR through HSP90, and CA reduces the binding stability of SREBP2 and HSP90 and enhances the binding of PXR and HSP90, thus reducing the nuclear accumulation of SREBP2 and PXR simultaneously. Moreover, CA promoted the phosphorylation of AMP-activated protein kinase (AMPK) and its binding to SREBP2. This was not conducive to the binding of HSP90 and SREBP2 but enhanced the binding of HSP90 and PXR, thereby inhibiting the nuclear translocation of SREBP2 and PXR and reducing intracellular cholesterol levels. However, no noticeable direct binding between AMPK and PXR was observed. CONCLUSION: CA downregulates NPC1L1 and HMGCR expression by acting on the AMPK/SREBP2 direct pathway and the AMPK/SREBP2/HSP90/PXR indirect pathway, thus retaining cholesterol homeostasis.

Pretreatment of hydroethanolic extract of Dillenia indica L. attenuates oleic acid induced NAFLD in HepG2 cells via modulating SIRT-1/p-LKB-1/AMPK, HMGCR & PPAR-α signaling pathways.

ETHNOPHARMACOLOGICAL RELEVANCE: Dillenia indica L. is an edible plant from the Dilleniaceae family present in the forest of India and other Asian countries. Different parts of this plant are being used in the traditional system of medicines for various diseases like diabetes, indigestion, asthma, jaundice, and rheumatic pain by various rural communities. This plant is very common among Khamptis traditional healers, the rural community of the Dhemaji district of Assam, ethnic communities of Dibru-Saikhowa Biosphere Reserve of Northeast, India for various medicinal uses. It is observed as a 'vat' suppressant and 'pitta' boosting medicine in Ayurveda. AIM OF THE STUDY: The aim of this research was to evaluate the effect of hydroethanolic extract of Dillenia indica leaf (DI-HET) against non-alcoholic fatty liver disease (NAFLD) as it is reported effective against jaundice in traditional medicine. We are also planning to see the various molecular mechanisms responsible for its effect if it is efficacious. STUDY DESIGN/METHOD: An in vitro model for NAFLD was employed in this study. For this HepG2 cells were incubated with 100 µM of oleic acid (OA) for 24 h. For evaluation of the effect of DI-HET, the extracts (5 or 10 µg/mL) were pretreated to the OA group. Fenofibrate was the positive control. Various parameters relevant to lipogenesis and ß-oxidation of fatty acids like intracellular lipid accumulation, reactive oxygen species (ROS), mitochondrial stress, and key proteins were studied. RESULTS: DI-HET significantly reduced the intracellular lipid accumulation in OA treated cells. And also substantially decreased the expression of lipogenic proteins and increased ß-oxidation in the OA group. OA induced ROS generation was found to reduce with DI-HET treatment. Western blot analysis showed that the expression of LXR-α, SREBP-1C, SREBP-2, HMGCR, FAS, CD-36, and ACOX-1 were downregulated while that of SIRT-1, p-LKB-, p-AMPK, p-ACC, CPT-1, and PPAR-α upregulated in DI-HET treatment. LCMS/MS analysis showed the presence of polyphenols like naringenin, catechin, epicatechin, shikimic acid, syringic acid, vanillic acid, and kaempferol. CONCLUSION: These results suggest that DI-HET is effective against NAFLD by activation of the SIRT-1/p-LKB-1/AMPK signaling pathway via polyphenols present in the extract.

Ameliorations in dyslipidemia and atherosclerotic plaque by the inhibition of HMG-CoA reductase and antioxidant potential of phytoconstituents of an aqueous seed extract of Acacia senegal (L.) Willd in rabbits.

The assigned work was aimed to examine the capability of phytoconstituents of an aqueous seed extract of Acacia senegal (L.) Willd to inhibit HMG-CoA reductase and regression of the atherosclerotic plaque. The chemical fingerprinting of the test extract was assessed by LC-MS/MS. Consequently, the analyses of in-vitro, in-vivo, and in-silico were executed by using the standard protocols. The in-vitro assessment of the test extract revealed 74.1% inhibition of HMG-CoA reductase. In-vivo assessments of the test extract indicated that treated hypercholesterolemic rabbits exhibited a significant (P≤0.001) amelioration in the biomarker indices of the dyslipidaemia i.e., atherogenic index, Castelli risk index(I&II), atherogenic coefficient along with lipid profile. Subsequently, significant reductions were observed in the atherosclerotic plaque and antioxidant levels. The in-silico study of molecular docking shown interactions capabilities of the leading phytoconstituents of the test extract i.e., eicosanoic acid, linoleic acid, and flavan-3-ol with target protein of HMG-CoA reductase. The values of RSMF and potential energy of top docked complexes were show significant interactions. Accordingly, the free energy of solvation, interaction angle, radius of gyration and SASA were shown significant stabilities of top docked complex. The cumulative data of results indicate phytoconstituents of an aqueous seed extract of Acacia senegal have capabilities to inhibit the HMG-CoA reductase and improve the levels of antioxidants.

Long-lasting impact of perinatal dietary supplementation of omega 3 fatty acids on mevalonate pathway: potential role on neuron trophism in male offspring hippocampal formation.

Objective: We were aimed at evaluating the long-term impact of perinatal an omega-3 fatty acid-enriched diet on the mevalonate/cholesterol pathway in the brain of male offspring.Methods: Female rats were fed with standard or omega-3 fatty acid-enriched diet during pregnancy and lactation. Liver, brain and plasma were collected from infant, adolescent and adult male offspring for subsequent biochemical and morphological analyses.Results: The omega-3 enriched diet induced region-dependent changes of the 3-hydroxy 3-methylglutaryl Coenzyme A reductase in the brain and affected notably RhoA/CREB signaling and the nerve growth factor content in the hippocampus. Our data reveal a long-lasting impact of perinatal omega-3 fatty acid supplementation on hippocampal nerve growth factor levels mediated by reduced 3-hydroxy 3-methylglutaryl Coenzyme A reductase activation state and enhanced CREB signaling.Discussion: These data underline the importance of the perinatal omega-3 enriched diet for adult brain function and reveal a new pathway important for nerve growth factor regulation.

Flavonoid-statin interactions causing myopathy and the possible significance of OATP transport, CYP450 metabolism and mevalonate synthesis.

3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase inhibitors, statins, are a primary treatment for hyperlipidemic cardiovascular diseases which are a leading global cause of death. Statin therapy is life saving and discontinuation due to adverse events such as myotoxicity may lead to unfavourable outcomes. There is no known mechanism for statin-induced myotoxicity although it is theorized that it is due to inhibition of downstream products of the HMG-CoA pathway. It is known that drug-drug interactions with conventional medicines exacerbate the risk of statin-induced myotoxicity, though little attention has been paid to herb-drug interactions with complementary medicines. Flavonoids are a class of phytochemicals which can be purchased as high dose supplements. There is evidence that flavonoids can raise statin plasma levels, increasing the risk of statin-induced myopathy. This could be due to pharmacokinetic interactions involving hepatic cytochrome 450 (CYP450) metabolism and organic anion transporter (OATP) absorption. There is also the potential for flavonoids to directly and indirectly inhibit HMG-CoA reductase which could contraindicate statin-therapy. This review aims to discuss what is currently known about the potential for high dose flavonoids to interact with the hepatic CYP450 metabolism, OATP uptake of statins or their ability to interact with HMG-CoA reductase. Flavonoids of particular interest will be covered and the difficulties of examining herbal products will be discussed throughout.

The Changes in Endogenous Metabolites in Hyperlipidemic Rats Treated with Herbal Mixture Containing Lemon, Apple Cider, Garlic, Ginger, and Honey.

An herbal mixture composed of lemon, apple cider, garlic, ginger and honey as a polyphenol-rich mixture (PRM) has been reported to contain hypolipidemic activity on human subjects and hyperlipidemic rats. However, the therapeutic effects of PRM on metabolites are not clearly understood. Therefore, this study aimed to provide new information on the causal impact of PRM on the endogenous metabolites, pathways and serum biochemistry. Serum samples of hyperlipidemic rats treated with PRM were subjected to biochemistry (lipid and liver profile) and hydroxymethylglutaryl-CoA enzyme reductase (HMG-CoA reductase) analyses. In contrast, the urine samples were subjected to urine metabolomics using 1H NMR. The serum biochemistry revealed that PRM at 500 mg/kg (PRM-H) managed to lower the total cholesterol level and low-density lipoprotein (LDL-C) (p < 0.05) and reduce the HMG-CoA reductase activity. The pathway analysis from urine metabolomics reveals that PRM-H altered 17 pathways, with the TCA cycle having the highest impact (0.26). Results also showed the relationship between the serum biochemistry of LDL-C and HMG-CoA reductase and urine metabolites (trimethylamine-N-oxide, dimethylglycine, allantoin and succinate). The study's findings demonstrated the potential of PRM at 500 mg/kg as an anti-hyperlipidemic by altering the TCA cycle, inhibiting HMG-CoA reductase and lowering the LDL-C in high cholesterol rats.

Polyphenols from Citrus Tacle® Extract Endowed with HMGCR Inhibitory Activity: An Antihypercholesterolemia Natural Remedy.

Tacle® is a citrus fruit obtained from the crossbreeding of Clementine and Tarocco cultivars. This fruit retains a promising nutraceutical potential most likely due to a high content in polyphenols, among which the main constituents are the two glycosides naringin and hesperidin. Herein, we evaluated, through an in vitro assay, the capability of Tacle extracts to inhibit the hydroxymethylglutaryl-CoA reductase enzyme, which plays a key role in cholesterol biosynthesis. The results obtained spurred us to investigate whether the anti-enzymatic activity observed may be due to a direct interaction of aglycones naringenin and hesperetin with the enzyme catalytic site. Molecular docking simulations indicated that these two compounds are able to anchor to the protein with binding modes and affinities similar to those found for statins, which represent mainstream medications against hypercholesterolemia. The overall results showed an interesting nutraceutical potential of Tacle, suggesting that its extract could be used for dietary supplementation in the treatment of moderate hypercholesterolemia.

In-silico HMG-CoA reductase-inhibitory and in-vivo anti-lipidaemic/anticancer effects of carotenoids from Spondias mombin.

OBJECTIVES: Inhibition of HMG-CoA (3-hydroxy-3-methylglutaryl coenzyme A) reductase, the rate rate-determining enzyme for the biogenesis of cholesterol is known to show antineoplastic effects. Therefore, this study investigates the in-silico HMG-CoA reductase (HMGCR)-inhibitory and in-vivo anti-lipidaemic/anticancer effects of carotenoids from Spondias mombin. METHODS: Carotenoids from S. mombin leaves were characterized with the aid of liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS). The characterized phytochemicals were obtained from PubChem. They were docked into the orthosteric site of human HMGCR (Protein Data Bank code 1HW8) using AutoDock 4.0 suites. DMBA (7,12-dimethylbenz[a]anthracene) model of breast cancer was treated with the carotenoids extract from S. mombin (100 mg/kg and 200 mg/kg doses) to assess its anti-lipidaemic cum anticancer effects. KEY FINDINGS: Carotenoids from S. mombin; beta-carotene-15,15'-epoxide, astaxanthin and 7,7',8,8'-tetrahydro-ß-ß-carotene demonstrate HMGCR inhibition. They form hydrophobic interactions with key residues within the catalytic domain of HMGCR. The carotenoids extract exhibits anti-lipidaemic/anticancer effects, lowering serum triglyceride, LDL and cholesterol concentration. It increases HDL concentration and downregulates the expression of HMGR, AFP, CEACAM-3, BRCA-1 and HIF-1 mRNAs. CONCLUSION: Carotenoids from S. mombin demonstrate HMG-CoA reductase (HMGCR) inhibition, anti-lipidaemic, and anticancer effects. The inhibition of HMGCR by the carotenoids extract further poses it as a potential anti-hypercholesterolaemia compounds.

Targeting the Mevalonate Pathway for Treating Esophageal Cancer.

PURPOSE: To asseess whether the mevalonate pathway can be targeted in managing patients with esophageal cancer. METHODS: This a narrative review of peer-revieweed publications indexed in MedLine PubMed. The search was conducted by using "Esophageal cancer", "Mevalonate pahtway", "Statins", and "Translational research." RESULTS: The mevalonate pathway is an important metabolic pathway that is involved in various cellular functions. Its downstream products are essential for cell-signaling, cell membrane integrity, protein synthesis, and cellular respiration. Statins, a class of medications that are best known as lipid-lowering drugs, inhibit the rate-limiting enzyme of this pathway. Many studies have shown that a variety of cancerous cells have a dysregulated mevalonate pathway. Esophageal cancer is a malignancy that has a poor prognosis, which is mainly due to patients presenting once the cancer is in the advances stages. Chemotherapy has been the mainstay for treating esophageal cancer. However, these agents are not consistently effective and fail to differentiate between the different subtypes of esophageal cancers. Identifying other classes of drugs which could possess anti esophageal cancer properties is appealing. CONCLUSION: There is a growing body of literature that has shown the anti-cancer properties of statins in the setting of various malignancies. Herein, we summarize the current literature as it pertains to how the mevalonate pathway can be targeted by statins for potentially treating esophageal cancer.

Hepatoprotective Effect of Supercritical Carbon Dioxide Extracted Dabai Pulp Oil and Its Defatted Pulp.

All food scientists must utilize plants for their application as functional foods to reduce hypercholesterolemia incidence through diet. Canarium odontophyllum (dabai) is a novel source for new healthy oil and functional foods. In this work, we evaluate the hepatoprotective effects of supercritical carbon dioxide (SC-CO2) extracted dabai pulp oil (DPO) and defatted dabai pulp (DDP) against hypercholesterolemia elicited by a high-cholesterol diet in rats. Our results show that DPO and DDP supplementation exerted beneficial hypocholesterolemic effects against the high-cholesterol diet-fed rat. Nevertheless, supplementation with DDP revealed superior total cholesterol, low-density lipoprotein, and HMG-CoA reductase lowering efficacy (p < 0.05). Supplementation of either DPO or DDP did not significantly affect AST and ALT levels than normal rats (p > 0.05). Therefore, DDP and DPO are considered as having no toxicological significance. The histological section of rats treated with DPO and DDP showed improved steatosis in hepatocytes. HPLC analysis revealed that DPO and DDP contained syringic acid, which plays an important role in the beneficial effect. In conclusion, our results support the hypocholesterolemic and hepatoprotective effects of DPO and DDP in the hypercholesterolemic rats model.

[Cloning and expression analysis of 3-hydroxy-3-methylglutaryl coenzyme A reductase genes from Siraitia grosvenorii].

3-Hydroxy-3-methylglutaryl coenzyme A reductase(HMGR) is the first rate-limiting enzyme in the mevalonic acid(MVA)pathway and it is an important regulatory site in the metabolism of terpenoids in the cytoplasm. In this study, Siraitia grosvenorii that had been pollinated 0 day,1 day,3 days,15 days and 30 days were used as experimental materials. Based on the transcriptome data, two HMGR genes were cloned from S. grosvenorii cDNA and named SgHMGR2(GenBank Accession Numbers MT270447) and SgHMGR3(GenBank Accession Number MT270448). The two genes contain open reading frames(ORFs) of 1 746 bp and 1 782 bp, encoding 582 and 594 amino acids, and their molecular masses are estimated to be 62.7,63.2 kDa, respectively. Isoelectric point are 8.34 and 7.47, both of which do not contain signal peptides, are non-secretory proteins, and have two transmembrane structures. Combining the conserved regions of the proteins and the analysis of the evolutionary tree, it was confirmed that the genes are indeed HMGR family genes. Real-time PCR was used to detect the expression pattern of SgHMGRs at different times after pollination, and the highest expression level was 15 days after pollination. Finally, two full-length SgHMGRs were cloned from S. grosvenorii for the first time, and the differential expression of SgHMGRs at different times after pollination was revealed, providing a research basis for the mining of key enzyme gene elements in the biosynthesis pathway of S. grosvenorii terpenoids.

Mikania micrantha Extract Inhibits HMG-CoA Reductase and ACAT2 and Ameliorates Hypercholesterolemia and Lipid Peroxidation in High Cholesterol-Fed Rats.

The present study aimed to determine the effect of an ethyl acetate extract of Mikania micrantha stems (EAMMS) in hypercholesterolemia-induced rats. Rats were divided into a normal group (NC) and hypercholesterolemia induced groups: hypercholesterolemia control group (PC), simvastatin group (SV) (10 mg/kg) and EAMMS extract groups at different dosages of 50, 100 and 200 mg/kg, respectively. Blood serum and tissues were collected for haematological, biochemical, histopathological, and enzyme analysis. Total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), aspartate aminotransferase (AST), alanine aminotransferase (ALT), urea, creatinine, malondialdehyde (MDA) level, as well as enzymes of HMG-CoA reductase (HMGCR) and acetyl-CoA acetyltransferase 2 (ACAT2), were measured. Feeding rats with high cholesterol diet for eight weeks resulted in a significantly (p < 0.05) increased of TC, TG, LDL-C, AST, ALT and MDA levels. Meanwhile, the administration of EAMMS extract (50, 100 and 200 mg/kg) and simvastatin (10 mg/kg) significantly reduced (p < 0.05) the levels of TC, TG, LDL-C and MDA compared to rats in the PC group. Furthermore, all EAMMS and SV-treated groups showed a higher HDL-C level compared to both NC and PC groups. No significant difference was found in the level of ALT, AST, urea and creatinine between the different dosages in EAMMS extracts. Treatment with EAMMS also exhibited the highest inhibition activity of enzyme HMGCR and ACAT2 as compared to the control group. From the histopathological examination, liver tissues in the PC group showed severe steatosis than those fed with EAMMS and normal diet. Treatment with EAMMS extract ameliorated and reduced the pathological changes in the liver. No morphological changes showed in the kidney structure of both control and treated groups. In conclusion, these findings demonstrated that EAMMS extract has anti-hypercholesterolemia properties and could be used as an alternative treatment for this disorder.

Dietary Betaine Addition Promotes Hepatic Cholesterol Synthesis, Bile Acid Conversion, and Export in Rats.

It is widely reported how betaine addition regulates lipid metabolism but how betaine affects cholesterol metabolism is still unknown. This study aimed to investigate the role of betaine in hepatic cholesterol metabolism of Sprague-Dawley rats. Rats were randomly allocated to four groups and fed with a basal diet or a high-fat diet with or without 1% betaine. The experiment lasted 28 days. The results showed that dietary betaine supplementation reduced the feed intake of rats with final weight unchanged. Serum low-density-lipoprotein cholesterol was increased with the high-fat diet. The high-fat diet promoted cholesterol synthesis and excretion by enhancing the HMG-CoA reductase and ABCG5/G8, respectively, which lead to a balance of hepatic cholesterol. Rats in betaine groups showed a higher level of hepatic total cholesterol. Dietary betaine addition enhanced cholesterol synthesis as well as conversion of bile acid from cholesterol by increasing the levels of HMGCR and CYP7A1. The high-fat diet decreased the level of bile salt export pump, while dietary betaine addition inhibited this decrease and promoted bile acid efflux and increased total bile acid levels in the intestine. In summary, dietary betaine addition promoted hepatic cholesterol metabolism, including cholesterol synthesis, conversion of bile acids, and bile acid export.

Unripe Rubus coreanus Miquel Extract Containing Ellagic Acid Regulates AMPK, SREBP-2, HMGCR, and INSIG-1 Signaling and Cholesterol Metabolism In Vitro and In Vivo.

Our previous study demonstrated that a 5% ethanol extract of unripe Rubus coreanus (5-uRCK) has hypo-cholesterolemic and anti-obesity activity. However, the molecular mechanisms of its effects are poorly characterized. We hypothesized that 5-uRCK and one of its major bioactive compounds, ellagic acid, decrease cellular and plasma cholesterol levels. Thus, we investigated the hypocholesterolemic activity and mechanism of 5-uRCK in both hepatocytes and a high-cholesterol diet (HCD)-induced rat model. Cholesterol in the liver and serum was significantly reduced by 5-uRCK and ellagic acid. The hepatic activities of HMG-CoA and CETP were reduced, and the hepatic activity of LCAT was increased by both 5-uRCK extract and ellagic acid, which also caused histological improvements. The MDA content in the aorta and serum was significantly decreased after oral administration of 5-uRCK or ellagic acid. Further immunoblotting analysis showed that AMPK phosphorylation in the liver was induced by 5-uRCK and ellagic acid, which activated AMPK, inhibiting the activity of HMGCR by inhibitory phosphorylation. In contrast, 5-uRCK and ellagic acid suppressed the nuclear translocation and activation of SREBP-2, which is a key transcription factor in cholesterol biosynthesis. In conclusion, our results suggest that 5-uRCK and its bioactive compound, ellagic acid, are useful alternative therapeutic agents to regulate blood cholesterol.

Annatto-Derived Tocotrienol Promotes Mineralization of MC3T3-E1 Cells by Enhancing BMP-2 Protein Expression via Inhibiting RhoA Activation and HMG-CoA Reductase Gene Expression.

PURPOSE: Annatto-derived tocotrienol (AnTT) has been shown to improve bone formation in animal models of osteoporosis and promote differentiation of pre-osteoblastic cells. However, the mechanism of action of AnTT in achieving these effects is unclear. This study aims to investigate the mechanism of action of AnTT on MC3T3-E1 pre-osteoblasts via the mevalonate pathway. METHODS: Murine pre-osteoblastic cells, MC3T3-E1, were cultured with the density of 1 × 104 cells/mL and treated with 4 concentrations of AnTT (0.001-1 µg/mL). Expression of HMG-CoA reductase (HMGR) gene was carried out using qPCR after treatment with AnTT for 21 days. RhoA activation and bone morphogenetic protein-2 (BMP-2) were measured using immunoassay after 9 and 15 days of AnTT treatment. Lovastatin was used as the positive control. Mineralized nodules were detected using Von Kossa staining after 21 days of AnTT treatment. RESULTS: The results showed that HMGR was up-regulated in the lovastatin group on day 9 and 21 compared to the control. Lovastatin also inhibited RhoA activation (day 9 and 15) and increased BMP-2 protein (day 15). On the other hand, AnTT at 0.001 µg/mL (day 3) and 0.1 µg/mL (day 21) significantly down-regulated HMGR gene expression compared to the control. On day 21, HMGR gene expression was significantly reduced in all groups compared to day 15. AnTT at 0.1 µg/mL significantly decreased RhoA activation on day 9 compared to the control. AnTT at 1 µg/mL significantly increased BMP-2 protein on day 15 compared to the control (P<0.05). Mineralized calcium nodules were more abundant in AnTT treated groups compared to the control on day 21. CONCLUSION: AnTT suppresses the mevalonate pathway by downregulating HMGR gene expression and inhibiting RhoA activation, leading to increased BMP-2 protein in MC3T3-E1 cells. This explains the stimulating effects of AnTT on osteoblast mineralization.

Identification of Peptides Potentially Responsible for In Vivo Hypolipidemic Activity of a Hydrolysate from Olive Seeds.

Previous studies demonstrated that peptides produced by the hydrolysis of olive seed proteins using Alcalase enzyme showed in vitro multifunctional lipid-lowering capability. This work presents a deeper insight into the hypolipidemic effect of olive seed peptides. The capability of olive seed peptides to inhibit endogenous cholesterol biosynthesis through the inhibition of HMG-CoA reductase enzyme was evaluated observing a 38 ± 7% of inhibition. Two in vivo assays using different peptides concentrations (200 and 400 mg/kg/day) were designed to evaluate the hypolipidemic effect of olive seed peptides in male and female mice. A low concentration of hydrolysate reduced total cholesterol in male mice in a 20% after 11 weeks compared to the mice feeding with hypercholesterolemic diet. A higher hydrolysate concentration showed a greater reduction in total cholesterol (25%). The analysis of the olive seed hydrolysate by reverse phase high-performance liquid chromatography mass spectrometry (RP-HPLC-MS) enabled the identification of peptides that could be responsible for this hypolipidemic effect.

Aqueous extracts of Lindera aggregate (Sims) Kosterm leaves regulate serum/hepatic lipid and liver function in normal and hypercholesterolemic mice.

The leaves of Lindera aggregate (Sims) Kosterm. are traditionally used as healthy tea for the prevention and treatment of hyperlipidemia in Chinese. The aim of this study was to evaluate the antihyperlipidemic effects and potential mechanisms of the aqueous extracts from L. aggregate leaves (AqLA-L) on normal and hypercholesterolemic (HCL) mice. HCL mice were induced by high fat diet (HFD) and orally administrated with or without AqLA-L for ten days. The results showed that AqLA-L (0.3, 0.6, 1.2 g/kg) significantly reduced serum TG, ALT, but elevated fecal TG in normal mice. AqLA-L (0.3, 0.6, 1.2 g/kg) also remarkably lowered serum TC, TG, LDL, N-HDL, ALT, GLU, APOB, hepatic GLU and increased serum HDL, APOA-I, fecal TG levels in HCL mice. These results revealed that AqLA-L treatment regulated the disorders of the serum lipid and liver function, reduced hepatic GLU contents both in normal and HCL mice. The potential mechanisms for cholesterol-lowering effects of AqLA-L might be up-regulation of cholesterol 7-alpha-hydroxylase (CYP7A1) and ATP-binding cassette transporter A1 (ABCA1), as well as down-regulation of 3-hydroxy-3-methylglutaryl CoA reductase (HMGCR). The data indicated that AqLA-L has potential therapeutic value in treatment of hyperlipidemia with great application security.

Eryngium carlinae Ethanol Extract Corrects Lipid Abnormalities in Wistar Rats with Experimental Diabetes.

Abnormalities in lipid metabolism, associated with increased risk of cardiovascular disease (CVD), frequently occur in people with diabetes. Eryngium carlinae is a plant used in traditional medicine to treat lipid abnormalities. The chemical composition and hypolipidemic activity of the ethanolic extract of E. carlinae were analyzed to broaden our knowledge of its mechanism of action. The ethanolic extract of E. carlinae was tested for hypolipidemic activity by oral administration for 40 days. Atorvastatin, a widely used statin, was also administered to compare its effect with that of the extract. Serum was used for analysis of the lipid profile and liver microsomes to assess 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activity and low-density lipoprotein receptor (LDL-r) levels. The extract was able to reduce total cholesterol and non-high-density lipoprotein cholesterol (C-HDL) levels and increase the C-HDL levels reduced in diabetes, decreasing the atherogenic index and therefore the risk of suffering CVD at the same level as atorvastatin. The HMG-CoA reductase activity and LDL-r levels were not modified by the administration of E. carlinae. The results demonstrate the hypolipidemic potential of ethanol extract of E. carlinae and support its use in traditional medicine as a hypolipidemic agent.

Cloning, Purification, and Characterization of the Catalytic C-Terminal Domain of the Human 3-Hydroxy-3-methyl glutaryl-CoA Reductase: An Effective, Fast, and Easy Method for Testing Hypocholesterolemic Compounds.

3-hydroxy-3-methyl glutaryl-CoA reductase, also known as HMGR, plays a crucial role in regulating cholesterol biosynthesis and represents the main pharmacological target of statins. In mammals, this enzyme localizes to the endoplasmic reticulum membrane. HMGR includes different regions, an integral N-terminal domain connected by a linker-region to a cytosolic C-terminal domain, the latter being responsible for enzymatic activity. The aim of this work was to design a simple strategy for cloning, expression, and purification of the catalytic C-terminal domain of the human HMGR (cf-HMGR), in order to spectrophotometrically test its enzymatic activity. The recombinant cf-HMGR protein was heterologously expressed in Escherichia coli, purified by Ni+-agarose affinity chromatography and reconstituted in its active form. MALDI mass spectrometry was adopted to monitor purification procedure as a technique orthogonal to the classical Western blot analysis. Protein identity was validated by MS and MS/MS analysis, confirming about 82% of the recombinant sequence. The specific activity of the purified and dialyzed cf-HMGR preparation was enriched about 85-fold with respect to the supernatant obtained from cell lysate. The effective, cheap, and easy method here described could be useful for screening statin-like molecules, so simplifying the search for new drugs with hypocholesterolemic effects.

Evaluation of biological activities, and exploration on mechanism of action of matrine-cholesterol derivatives.

To develop new potential pesticides, a series of matrine-cholesterol derivatives were prepared by modifications of two non-food bioactive products matrine and cholesterol. Two N-phenylsulfonylmatrinic esters (5i and 5j) showed the most potent insecticidal activity against Mythimna separata Walker. Two N-benzylmatrinic esters (5e and 5g) exhibited the most promising aphicidal activity against Aphis citricola Van der Goot. Especially compound 5e showed good control effects in the greenhouse against A. citricola. Some interesting results of their structure-activity relationships were also observed. By reverse transcription polymerase chain reaction (RT-PCR) and quantitative real-time polymerase chain reaction (qRT-PCR) analysis of HMG-CoA reductase in apterous adults of A. citricola, it demonstrated that matrine and cholesterol may be the HMG-CoA reductase inhibitors, and the hydroxyl of cholesterol or the lactam ring of matrine may be important for acting with HMG-CoA reductase in A. citricola.