HMG-CoA Reductase Activity Research Articles

Red Yeast Rice or Lovastatin? A Comparative Evaluation of Safety and Efficacy Through a Multifaceted Approach.

The increasing use of red yeast rice (RYR) as a natural supplement to manage blood cholesterol levels is driven by its active compound, monacolin K (MK), which is chemically identical to the statin drug lovastatin (LOV). Despite its growing popularity, concerns persists regarding the safety and efficacy of RYR compared to pure statins. This study aimed to evaluate the phytochemical composition, pharmacological effects, and safety profile of various RYR samples in comparison with LOV. RYR samples with different MK content were analyzed using HPLC-DAD to quantify monacolins and other bioactive compounds. The inhibitory activity on HMG-CoA reductase was assessed through an enzymatic assay, while pharmacokinetic properties were predicted using invitro simulated digestion and in silico models. Invitro cytotoxicity was evaluated in intestinal, hepatic, renal, and skeletal muscle cell models. Additionally, the transcriptional levels of muscle damage-related target genes were evaluated by qRT-PCR in skeletal muscle cells treated with a selection of RYR samples. Significant variability in the phytochemical composition of RYR sampleswas observed, particularly in the content of secondary monacolins, triterpenes, and polyphenols. The RYR phytocomplex exhibited superior inhibition of HMG-CoA reductase activity compared to isolated LOV, suggesting synergistic effects between secondary monacolins and other compounds. Molecular insights revealed that RYR samples had a lower impact on muscle cells than LOV, as reflected also by cell viability. These findings suggest that RYR could serve as a safe alternative to purified statins. However, further research is needed to fully elucidate the mechanisms behind the synergistic activity of the phytocomplex and to firmly establish the clinical efficacy of this natural product.

In vivo, histopathological evaluation, and molecular docking of the antiatherosclerotic potential of Pangium edule leaf extract in cholesterol- and fat-enriched diet Wistar rats

Background: Pangi leaves, from the Pangium edule plant, are rich in flavonoids and saponins. Research has shown that flavonoids can lower blood cholesterol by blocking the activity of the enzyme HMG Co-A reductase. Saponins are linked to a lower risk of atherosclerosis because they can bind to cholesterol. However, the impact of pangi on high cholesterol levels has not been well-studied. This research aimed to explore how an ethanol extract from pangi leaves affects the lipid profiles of Wistar rats on a diet high in cholesterol and fat. Methods: The study involved four groups of ten rats each. One group served as a normal control, while the second consumed a high cholesterol and fat diet. The remaining two groups ate the same diet but also received 150 mg/kg or 450 mg/kg body weight of the pangi leaf extract. After 28 days, the rats' blood was tested for total cholesterol, triglycerides, HDL, and LDL. Results: The results showed significant differences in triglycerides and HDL levels among the groups. The pangi extract notably reduced triglycerides and increased HDL levels, even at the lower dose. It also lowered the atherogenic index and the TG/HDL ratio, both indicators of cardiovascular disease risk. These findings were supported by pathological examinations of the rats' aortas and computational analysis, which identified compounds in the pangi leaves that bind effectively to HMG-CoA reductase. Specifically, compounds such as (5.beta.) Pregnane-3,20.beta.-diol and psi.,psi.-Carotene showed strong interactions with this crucial cholesterol-producing enzyme, indicating their promise as potent agents to reduce cholesterol levels. The identified compounds exhibit favorable characteristics akin to drugs, enhancing their prospects as candidates for therapeutic use. Conclusion: The collective findings of this research indicate that the ethanol extract of pangi leaves positively influences the lipid profile in rats on a diet high in cholesterol and fat, suggesting its potential utility as a novel treatment option for hyperlipidemia.

Unveiling the Impact of Lactic Acid Bacteria on Blood Lipid Regulation for Cardiovascular Health

Lactic acid bacteria (LAB) are a group of microorganisms which are beneficial and well-characterized with respect to the flavor and texture of food products via fermentation. The accumulated literature has suggested that dietary intake of fermented foods rich in LAB is related to different health-promoting benefits; however, in recent years, emerging evidence suggests a contribution of LAB to blood lipid regulation and cardiovascular health via certain mechanisms. Different potential mechanisms for the lipid regulatory effects of LAB may include the interaction of hydroxymethylglutaryl-CoA (HMG-CoA) reductase and bile salt hydrolase activity and bile salt metabolism; gut microbiome modulation; and regulation of mRNA expression of genes related to fat metabolism in animal models and human studies. This review comprehensively aims to answer whether/how LAB influence blood lipids in both animal models and human studies while also uncovering the underlying mechanisms linking LAB to lipid metabolism.

Abstract 3063: Canonical And Noncanonical Heat Shock Factor 1 Signaling In Smooth Muscle Cells Promote Atherosclerotic Plaque Burden

Smooth muscle cells (SMCs) in atherosclerotic plaques undergo complex phenotypic modulation, characterized by migration from the aortic medial layer to the intima, proliferation, de-differentiation, and variable increases in molecular markers characteristic of macrophages, fibroblasts, osteogenic cells and mesenchymal stem cells. This transition is driven in part by cholesterol entering the endoplasmic reticulum (ER) and activating ER stress. The importance of ER stress-driven PERK signaling in atherosclerosis is underscored by the observation that SMC-specific deletion of Perk reduces lesion size by ~70% in hypercholesterolemic (HC) mice. HC mice harboring either an SM α-actin ( ACTA2 ) missense variant or SMC-specific deletion of the centrosomal scaffolding protein pericentrin ( PCNT ) have increased augmented plaque burden compared to their HC wildtype (WT) counterparts, despite having comparable serum lipid levels. We went on to demonstrate that both these genetic alterations increase SMC cytosolic stress and activation of canonical heat shock factor 1 (HSF1) signaling, which in turn increases HMG-CoA reductase (HMGCR) activity and cholesterol biosynthesis, ER stress, PERK signaling, SMC phenotypic modulation and finally, augments the plaque burden. We also noted another distinct pro-atherogenic form of HSF1 activation in SMCs: SMCs in culture exposed to high levels of exogenous cholesterol activate PERK signaling, but also consistently activate HSF1, and blocking PERK signaling prevents HSF1 activation, suggesting “noncanonical” HSF1 activation. While global loss of Hsf1 in HC mice reduces plaque burden, we generated tamoxifen-inducible SMC-specific Hsf1 -deficient mice ( Hsf1 SMC-/- ) to assess the role of HSF1 signaling in SMCs of HC mice. Hyperlipidemia was induced in these mice by a single injection of AAV- PCSK9 DY followed by a high fat diet for 12 weeks. En face aortic Oil Red O staining demonstrated that Hsf1 SMC-/- mice had 67% reduction in plaque size in the whole aorta (p=0.0007), compared to HC WT mice, similar to the results seen with SMC-specific Perk deficiency. These data suggest distinct roles of canonical and noncanonical HSF1 signaling in SMCs that contribute to atherosclerotic plaque burden.

Hydroxymethylglutaryl-CoA reductase activity is essential for mitochondrial β-oxidation of fatty acids to prevent lethal accumulation of long-chain acylcarnitines in the mouse liver.

Statins are competitive inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase (HMGCR), and exert adverse effects on mitochondrial function, although the mechanisms underlying these effects remain unclear. We used a tamoxifen-induced Hmgcr-knockout (KO) mouse model, a multi-omics approach and mitochondrial function assessments to investigate whether decreased HMGCR activity impacts key liver energy metabolism pathways. We established a new mouse strain using the Cre/loxP system, which enabled whole-body deletion of Hmgcr expression. These mice were crossed with Rosa26Cre mice and treated with tamoxifen to delete Hmgcr in all cells. We performed transcriptomic and metabolomic analyses and thus evaluated time-dependent changes in metabolic functions to identify the pathways leading to cell death in Hmgcr-KO mice. Lack of Hmgcr expression resulted in lethality, due to acute liver damage caused by rapid disruption of mitochondrial fatty acid β-oxidation and very high accumulation of long-chain (LC) acylcarnitines in both male and female mice. Gene expression and KO-related phenotype changes were not observed in other tissues. The progression to liver failure was driven by diminished peroxisome formation, which resulted in impaired mitochondrial and peroxisomal fatty acid metabolism, enhanced glucose utilization and whole-body hypoglycaemia. Our findings suggest that HMGCR is crucial for maintaining energy metabolism balance, and its activity is necessary for functional mitochondrial β-oxidation. Moreover, statin-induced adverse reactions might be rescued by the prevention of LC acylcarnitine accumulation.

Virgin Coconut Oil and Palm Tocotrienol Supplementation: Effects on Lipid Parameters of Experimental Rats

Virgin coconut oil (VCO) and palm tocotrienol (TT) possess cholesterol-regulating properties, but their combined effects remained unexplored. Thus, this study aims to determine their individual and combination effects on lipid parameters in ovariectomised (OVX) rats on hypercholesterolemic diet. Female Sprague-Dawley rats were ovariectomised except for the sham group, assigned into (i) sham-operated fed with basal rat diet, (ii) OVX control, (iii) V1 (OVX + VCO 1.43 mL/kg), (iv) V2 (OVX + VCO 4.29 mL/kg), (v) TT (OVX + TT 30 mg/kg), (vi) V1+TT (OVX + VCO 1.43 mL/kg + TT 30 mg/kg) and (vii) V2+TT (OVX + VCO 4.29 mL/kg + TT 30 mg/kg). Groups (ii) to (vii) were fed with 2% cholesterol mixed with five-time heated palm oil. VCO and TT alone or in combination reduced food intake, visceral fat weight, thiobarbituric acid reactive substances and HMG-CoA reductase activity significantly (p<0.05 vs the OVX control). HDL was reduced significantly in V1, V2, and V1+TT compared to the TT and V2+TT (p<0.05). The increase in LDL was the lowest in V1 compared to other groups (p<0.05). V2 and TT significantly reduced total cholesterol compared to other supplementations (p<0.05). All supplementations were found to reduce triglyceride compared to the OVX control group (p<0.05). The increase in apolipoprotein A was higher in V2+TT than other groups (p<0.05). The reduction in apolipoprotein B was higher in V1+TT and V2+TT than the V1, V2 and TT. VCO and TT exerted beneficial effects on lipid parameters, but the efficacy was not better than individual agents.

Gold electrode modified with proteoliposome-derived bilayer for electrochemical studies of HMG‑CoA reductase and its inhibition

Electrochemical methods are used to characterize transport phenomena in the presence of membrane proteins to monitor changes in their catalytic properties or activity in the presence of activators or inhibitors. Because membrane proteins are fully active in their natural environment, the lipid membrane, electrochemical investigations of enzymes should be carried out when they are present in an appropriate lipid bilayer deposited on an electrode surface. Here, HMG-CoA reductase (HMGR), the membrane protein responsible for cholesterol synthesis, and its related coenzyme (HMG-CoA) were incorporated into a lipid bilayer obtained by spreading proteoliposomes on the surface of a gold electrode modified with a thioglucose. Nicotinamide adenine dinucleotide phosphate, NADPH was oxidized to NADP+ during the enzymatic reaction when HMG-CoA was reduced to the product, mevalonate, which is further transformed into cholesterol. The reconstitution of HMG-CoA reductase and its mechanism were investigated by following the NADP+ reduction on the electrode using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The activity of HMGR was studied over time and in the presence of fluvastatin, an exemplary HMGR reductase inhibitor commonly used to treat hypercholesterolemia. The inhibitory effect of the statin was electrochemically evaluated by monitoring the decrease of NADP+ reduction current and changes in the impedance parameters of the HMGR-proteoliposome-derived bilayer.

In Silico Compounds Analysis in Ginger (Zingiber Officinale) as Candidate for Acute Coronary Syndrome Medication

Based on the World Health Organization and other authorized health organizations, heart disease is one of the diseases with the largest contributor to death in the world, including Acute Coronary Syndrome with an estimated number of patients of 126 million in 2020. This research entails phytoconstituents of Zingiber officinale as possible Acute Coronary Syndrome medication with in silico methods by altering the activity of HMG-CoA Reductase, PPAR-α, PPAR-γ, NPC1L1, β1-AR, ACE and P2Y12R. This research used Molegro Virtual Docker 6.0 as tool to analyze the compounds with docking computation approach and also utilize Protein Data Bank (PDB) files : 1HWK, 2ZNN, 4EMA, 4AMJ, 2YDM, 4PXZ and 7DFZ. Chemdraw 3D was used in order to minimize the ligand’s energy. Furthermore, to analyze the pharmacokinetics aspects, this study involved pkCSM and SwissADME to predict a few parameters in each aspect, and finalized the research with Dynamic Molecular approach with YASARA.

Abstract 14547: Genetically Predicted Inhibition of HMG-CoA Reductase Reduces Risk of DNMT3A Clonal Hematopoiesis

Introduction: Clonal hematopoiesis (CH) is associated with increased morbidity and mortality from cancer and cardiovascular diseases including heart failure and ischemic heart disease. At present no medications are known to protect from CH. However, leukemia cells with equivalent mutations show sensitivity to statin-induced cell death. Aims: To evaluate the association of LDL-C lowering genetic variants at HMGCR (the target of statins) with CH risk using two-sample Mendelian randomization. Methods: We investigated whether lower LDL-C genetically predicted by 6 variants at HMGCR associates with CH risk. Secondary exposures included a polygenic instrument of 74 LDL-C-lowering genome-wide variants. Genetic associations for LDL-C derived from a genome-wide association study (GWAS) meta-analysis of circulating LDL-C levels by the Global Lipid Genetics Consortium (N≤188,578 individuals of European ancestry). Outcome associations for CH were from a GWAS in 368,526 European individuals in UK Biobank. Results: Genetically predicted reduction in HMG-CoA reductase activity equivalent to a 38.7mg/dL lower circulating LDL-C level was associated with reduced odds of overall CH (OR 0.75, 95% CI 0.58-0.97, P = 0.027) or DNMT3A CH (OR 0.64, 95% CI 0.48-0.86, P = 0.003) but not TET2 CH (OR 1.12, 95% CI 0.63-2.00, P = 0.70). Associations were consistent across all 6 HMGCR variants in sensitivity analyses. Co-localization plots showed evidence of co-localization of LDL-C with DNMT3A CH and overall CH at the HMGCR locus. Associations were stronger for CH with variant allele fraction ≥10%, and, statins suppressed colony formation of mutant DNMT3A cells in vitro , suggesting statins may limit clonal expansion. In a secondary analysis to explore LDL-C dependence, LDL-C lowering predicted by the polygenic instrument did not associate with overall or DNMT3A CH but associated with increased odds of TET2 CH (OR 1.13, 95% CI 1.01-1.27, P = 0.03). Findings were replicated in a non-European cohort. Conclusions: Genetically predicted lifelong reduction of HMG-CoA reductase activity was associated with reduced risk of overall and DNMT3A -mutant CH, likely by LDL-C-independent mechanisms. This provides a strong rationale for clinical trials testing the effects of statins in CH.

In vitro cholesterol lowering activity of Ganoderma australe mycelia based on mass spectrometry, synchrotron Fourier-transform infrared analysis and liver-spheroid bioactivity

Mycelia were cultivated from a Thai wild mushroom identified as Ganoderma australe based on polymerase chain reaction (PCR) and morphological analyses. The mycelial extracts were examined for their active ingredients using a liquid chromatography-tandem mass spectrometry (LC‒MS/MS) method. This revealed the presence of lovastatin and tentative compounds including p-coumaric, nicotinamide, gamma-aminobutyric acid, choline, nucleosides, amino acids, and saccharides. The extracts had an inhibitory effect on the activity of HMG-CoA reductase in a concentration-dependent manner. At 2.5 mg/mL, the G. australe extracts did not interfere with the viability of HepG2 spheroids, but their biochemical composition was altered as determined by Fourier-transform infrared (FTIR) spectroscopy. The lipid profile of the spheroids treated with the mycelial extract was distinct from that of the control and the 5 µM lovastatin treatment, corresponding with the production of cholesterol by the spheroids. The mycelia of G. australe increased the percentage of high-density lipoprotein (HDL) production to 71.35 ± 2.74%, compared to the control and lovastatin-treated spheroids (33.26 ± 3.15% and 32.13 ± 3.24%, respectively). This study revealed the superior effect of natural compound mixtures to pure lovastatin, and the potential use of Thailand’s wild G. australe as a functional food to prevent or alleviate hypercholesterolemia.

Triterpenoids from Protorhus longifolia Exhibit Hypocholesterolemic Potential via Regulation of Cholesterol Biosynthesis and Stimulation of Low-Density Lipoprotein Uptake in HepG2 Cells.

The increasing incidence of hypercholesterolemia-related diseases even in the presence of the currently available cholesterol-lowering drugs indicates a need to discover new therapeutic drugs. This study aimed to investigate the hypocholesterolemic potential of two triterpenoids isolated from Protorhus longifolia stem bark. In silico techniques and in vitro enzyme assays were used to evaluate the potential inhibition of cholesterol esterase and HMG-CoA reductase by the triterpenoids (ARM-2 and RA-5). The toxicity, modulation of low-density lipoprotein (LDL) uptake, and associated gene expression were determined in HepG2 hepatocytes. In silico molecular docking revealed that ARM-2 compared with RA-5 has a relatively stronger binding affinity for both enzymes. Both triterpenoids further demonstrated promising in silico drug-likeness properties and favorable ADMET profiles characterized by high intestinal absorption and lack of CYP450 enzyme inhibition. The compounds further showed, to varying degrees of efficacy, inhibition of cholesterol micellization as well as both cholesterol esterase and HMG-CoA reductase activities with IC50 values ranging from 16.4 to 41.1 μM. Moreover, enhanced hepatic cellular LDL uptake and the associated upregulation of the LDL-R and SREBP-2 gene expression were observed in the triterpenoid-treated HepG2 cells. It is evident that the triterpenoids, especially ARM-2, possess hypocholesterolemic properties, and these molecules can serve as leads or structural templates for the development of new hypocholesterolemic drugs.

Smooth muscle α-actin missense variant promotes atherosclerosis through modulation of intracellular cholesterol in smooth muscle cells.

The variant p.Arg149Cys in ACTA2, which encodes smooth muscle cell (SMC)-specific α-actin, predisposes to thoracic aortic disease and early onset coronary artery disease in individuals without cardiovascular risk factors. This study investigated how this variant drives increased atherosclerosis. Apoe-/- mice with and without the variant were fed a high-fat diet for 12 weeks, followed by evaluation of atherosclerotic plaque formation and single-cell transcriptomics analysis. SMCs explanted from Acta2R149C/+ and wildtype (WT) ascending aortas were used to investigate atherosclerosis-associated SMC phenotypic modulation. Hyperlipidemic Acta2R149C/+Apoe-/- mice have a 2.5-fold increase in atherosclerotic plaque burden compared to Apoe-/- mice with no differences in serum lipid levels. At the cellular level, misfolding of the R149C α-actin activates heat shock factor 1, which increases endogenous cholesterol biosynthesis and intracellular cholesterol levels through increased HMG-CoA reductase (HMG-CoAR) expression and activity. The increased cellular cholesterol in Acta2R149C/+ SMCs induces endoplasmic reticulum stress and activates PERK-ATF4-KLF4 signaling to drive atherosclerosis-associated phenotypic modulation in the absence of exogenous cholesterol, while WT cells require higher levels of exogenous cholesterol to drive phenotypic modulation. Treatment with the HMG-CoAR inhibitor pravastatin successfully reverses the increased atherosclerotic plaque burden in Acta2R149C/+Apoe-/- mice. These data establish a novel mechanism by which a pathogenic missense variant in a smooth muscle-specific contractile protein predisposes to atherosclerosis in individuals without hypercholesterolemia or other risk factors. The results emphasize the role of increased intracellular cholesterol levels in driving SMC phenotypic modulation and atherosclerotic plaque burden.

Of Ethanol Extract of Cinnamon Bark (Cinnamomum burmanii) on the Lipid Profile and Malondialdehyde of Dyslipidemic Rats

Dyslipidemia is a risk factor for atherosclerosis. Dyslipidemia conditions and malondialdehyde (MDAs) increased can cause oxidative stress. Cinnamon contains antioxidant compounds that have a hypolipidemic effect. This study aimed to determine the effect of cinnamon bark ethanol extract on triglycerides, total cholesterol, LDL, HDL, and MDA in dyslipidemic rats. In this study, rats were divided into five groups, a negative control group: which received standard feed, a positive control group: which received a high-fat diet and PTU, the groups that received a high-fat diet, PTU, cinnamon bark ethanol extract (EECB) 125 mg/Kg BW, 250 mg/Kg BW, 500 mg/Kg BW. The results of the analysis showed a decrease in triglyceride levels in all groups given EECB (p <0.05). Total and LDL cholesterol levels decreased in the 125 mg/Kg BW EECB group, and malondialdehyde decreased in the 500 mg/Kg BW EECB group (p <0.05). HDL levels did not increase. The ethanol extract of cinnamon bark was able to improve lipid profiles because it contains cinnamaldehyde and quercetin that can inhibit HMG CoA reductase activity, as well as flavonoids, tannins, and cinnamate which are able to reduce triglyceride and MDA levels.
 Keywords: cinnamon, dyslipidemia, malondialdehyde, lipid profile.

Lactobacillus fermentum MCC2760 abrogate high-fat induced perturbations in the enterohepatic circulation of bile acids in rats

This study in hyperlipidemic rats elucidated the effect of Lactobacillus fermentum MCC2760 on intestinal bile acid (BA) uptake, hepatic BA synthesis, and enterohepatic BA transporters. Diets rich in saturated fatty acids [coconut oil (CO)] and omega-6 fatty acids [sunflower oil (SFO)] at 25g fat/100g diet were fed to rats with or without MCC2760 (109 cells/kg body weight). After 60days of feeding, intestinal BA uptake and expression of Asbt, Osta/b mRNA and protein, and hepatic expression of Ntcp, Bsep, Cyp7a1, Fxr, Shp, Lrh-1, and Hnf4a mRNA were measured. Hepatic expression of HMG-CoA reductase protein and its activity and total BAs in serum, liver, and feces were assessed. Hyperlipidaemic groups (HF-CO and HF-SFO) had: 1) increased intestinal BA uptake, Asbt and Osta/b mRNA expression, and ASBT staining 2) increased BA in serum, 3) decreased hepatic expression of Ntcp, Bsep, and Cyp7a1 mRNA, and NTCP staining 4) increased activity of HMG-CoA reductase, 5) increased hepatic expression of Fxr and Shp mRNA, 6) decreased hepatic expression of Lrh-1 and Hnf4a mRNA, and 7) decreased BA in Feces when compared to their respective controls (N-CO and N-SFO) and experimental groups (HF-CO+LF and HF-SFO+LF). Immunostaining revealed increased intestinal Asbt and hepatic Ntcp protein expression in the HF-CO and HF-SFO groups compared to control and experimental groups. Incorporating probiotics like MCC2760 abrogated hyperlipidemia-induced changes in the intestinal uptake, hepatic synthesis, and enterohepatic transporters of BA in rats. Probiotic MCC2760 can be used to modulate lipid metabolism in high-fat-induced hyperlipidemic conditions.

Circulating Human Metabolites Resulting from TOTUM-070 Absorption (a Plant-Based, Polyphenol-Rich Ingredient) Improve Lipid Metabolism in Human Hepatocytes: Lessons from an Original Ex Vivo Clinical Trial.

TOTUM-070 is a patented polyphenol-rich blend of five different plant extracts showing separately a latent effect on lipid metabolism and potential synergistic properties. In this study, we investigated the health benefit of such a formula. Using a preclinical model of high fat diet, TOTUM-070 (3 g/kg of body weight) limited the HFD-induced hyperlipemia with a reduction in triglyceride (-32% after 6 weeks; -20.3% after 12 weeks) and non-HDL cholesterol levels (-21% after 6 weeks; -38.4% after 12 weeks). To further investigate such a benefit and its underlying mechanisms in humans, we designed an ex vivo clinical approach to collect the circulating bioactives resulting from TOTUM-070 ingestion and to determine their biological activities on human hepatocytes. Human serum was obtained from healthy subjects before and after intake of TOTUM-070 (4995 mg). The presence of circulating metabolites was assessed by UPLC-MS/MS. Serum containing metabolites was further incubated with hepatocytes cultured in a lipotoxic environment (palmitate, 250 µM). RNA sequencing analyses show that lipid metabolism was one of the most impacted processes. Using histologic, proteomic, and enzymatic assays, the effects of human TOTUM-070 bioactives on hepatocyte metabolism were characterized by (1) the inhibition of lipid storage, including both (2) triglycerides (-41%, p < 0.001) and (3) cholesterol (-50%, p < 0.001) intracellular content, (4) a reduced de novo cholesterol synthesis (HMG-CoA reductase activity -44%, p < 0.001), and (5) a lowered fatty acid synthase protein level (p < 0.001). Altogether, these data support the beneficial impact of TOTUM-070 on lipid metabolism and provide new biochemical insights in human mechanisms occurring in liver cells.

Inhibition of HMG-CoA Reductase Activity by Kersen Leaves (Muntingia calabura L.) to Prevent Hypercholesterolemia

Background: Hypercholesterolemia is a condition of total cholesterol level &gt;200 mg/dL and LDL &gt;130 mg/dL. HMG-CoA (3-hydroxy-3-ethylglutaryl-coenzyme A) reductase is an enzyme that has a role in cholesterol biosynthesis. Hence, inhibition of this enzyme led to the decrement of cholesterol level. The extract of Kersen leaves (Muntingia calabura L.) is known to contain flavonoids, terpenoids, steroids, tannins, phenolic, and alkaloids. Flavonoids work by inhibiting the HMG-CoA reductase activity, so that mevalonate cannot be formed and thus decrease the cholesterol synthesis. Objectives: The present study aimed to determine the effect of Kersen leaves extract (M. calabura L.) in inhibiting the HMG-CoA reductase activity in vitro. Material and Methods: The study is a true experimental study with a post-test-only control group design. The independent variables were ethanol, methanol, and n-hexane extracts of Kersen leaves. Moreover, the percentage inhibition of the enzyme was the dependent variable. The test was conducted in vitro using UV-Vis spectrophotometry with pravastatin as a positive control. Results: The inhibitory effects of ethanol, methanol, n-hexane extracts of Kersen leaves, and pravastatin towards HMG-CoA reductase activity were 85.56%, 59.75%, 92.03%, and 99.58%, respectively. Post Hoc One-Way ANOVA showed that the p-values of pravastatin with ethanol, methanol, and n-hexane extracts were 0.687, 0.048, and 0.931, respectively. The n-hexane and ethanol extracts were potent for inhibiting the enzyme activity (p&gt;0.05) comparable to pravastatin. Conclusion: The n-hexane and ethanol extracts of Kersen leaves could serve as a natural source of HMG-CoA reductase inhibitor to prevent hypercholesterolemia.

Design, synthesis, and biological evaluation of novel atorvastatin derivatives

Cardiovascular disease is the leading cause of death worldwide. High cholesterol level is a risk factor for coronary artery disease. Cholesterol production is regulated by the enzyme 3‑hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase. Statins, HMG-CoA reductase inhibitors, are often used as lipid-lowering drugs to prevent cardiovascular disease. Therefore, this study aimed to evaluate the inhibitory activity of several atorvastatin derivatives and assess their inhibitory activity against the HMG-CoA reductase enzyme. Atorvastatin derivatives S1, S2, and S3 were synthesized by acylation of the benzene ring of atorvastatin. Moreover, the amine group of atorvastatin was treated with ethanol and sulfuric acid, to provide atorvastatin-anthranilic acid derivatives (S4 and S5). An in silico docking study was performed on the HMG-CoA reductase (PDB ID: 1HWK), and it was observed that compound S3 with a propargyl functional group had the highest binding affinity (∆G= -6.8 kcal/mol). The obtained results showed that S3 compound could significantly inhibit HMG-CoA reductase activity compared to controls pravastatin and atorvastatin (P<0.05). The in vivo antihyperlipidemic activity results discovered that compound S3 increased HDL, and decreased cholesterol, LDL and triglyceride compared to the atorvastatin during 60 days of treatment (P < 0.05). Liver enzyme levels and rabbit liver histology study showed no toxicity for the S3 compound. Additionally, the S3 might be considered as an effective medicine in preventing atherosclerosis.

In Vivo Hypolipidemic Effects and Antioxidant Capacity of Pinus morrisonicola Hay Extracts by Supercritical Carbon Dioxide Extraction

Pinus morrisonicola hay (PM) is a pine tree unique to Taiwan, whose needles are used as traditional medicine and as functional drink. PME3-1 was made using supercritical extraction to evaluate the prevention of hyperlipidemia. This study explored the hypolipidemic effect of PME3-1 on hamsters on a high fat and cholesterol (HFC) diet. Three groups of hamsters were fed with PME3-1 (0.2, 1.0, and 5.0 mg/kg bw). After feeding for eight weeks, PME3-1 reduced the serum cholesterol, triglyceride levels, the low-density lipoprotein cholesterol/high-density lipoprotein cholesterol (LDL/HDL) ratio, and the swelling of the liver and kidney significantly (p &lt; 0.05). In addition, feeding the hamsters with 5.0 mg/kg bw of PME3-1 could significantly reduce their total lipid (TL) content, total cholesterol (TC) content, total triglyceride (TG) content, and the HMG-CoA reductase activity in the liver (p &lt; 0.05). Meanwhile, the antioxidant enzymes in the liver, glutathione peroxidase (GPx) and glutathione S-transferase (GST), can also improve, promoting the excretion of triglycerides (TG) and total cholesterol (TC) in the feces (p &lt; 0.05). Therefore, these results confirm that PME3-1 hypolipidemic and antioxidant regulating functions in vivo.

Pectin Feeding Influences Fecal Bile Acid Excretion, Hepatic Bile Acid and Cholesterol Synthesis and Serum Cholesterol in Rats

This study was designed to investigate the effects of pectin on cholesterol and bile acid metabolism and to elucidate the mechanisms involved in its hypolipidemic effect in rats. The key regulatory enzymes in cholesterol and bile acid metabolism, 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-CoA reductase) and cholesterol 7α-hydroxylase, were determined. Circulating, hepatic, and biliary lipid concentrations and fecal bile acid excretion were also measured. Male Wistar rats were fed a fiber-free or a pectin-supplemented (7 g/100 g) diet for 4 wk. Bile flow and the biliary secretion of both bile acids and cholesterol were not significantly different than controls in pectin-fed rats. The addition of pectin to the diet resulted in lower serum and liver cholesterol concentrations (-27 and -17%, respectively). Fecal bile acid excretion (+168%) and the hepatic activity of cholesterol 7α-hydroxylase (+70%) were significantly higher in pectin-fed animals. HMG-CoA reductase activity was also significantly greater (+11%) in the presence of dietary pectin. Results of our study indicate that pectin, by enhancing fecal bile acid excretion, may cause increased hepatic synthesis of bile acids and liver depletion of cholesterol in rats, which results in a higher rate of cholesterol synthesis and reduced serum cholesterol concentrations.

Averrhoa carambola leaves prevent dyslipidemia and oxidative stress in a rat model of poloxamer-407-induced acute hyperlipidemia.

Background: The star fruit [Averrhoa carambola L (Oxalidaceae)] is traditionally used in the treatment of many ailments in many countries. It possesses several pharmacological activities, including antioxidant and anti-inflammatory effects. However, it contains the neurotoxic caramboxin and its high content of oxalic acid limits its consumption by individuals with compromised kidney function. This study assessed the anti-hyperlipidemic and antioxidant activities of different fractions of the methanolic extract of A. carambola leaves (MEACL). Methods: The antioxidant activity was investigated using FRAP, and ABTS and DPPH radical-scavenging assays and the inhibitory activity toward pancreatic lipase (PL) and HMG-CoA reductase was assayed in vitro. Acute hyperlipidemia was induced by poloxamer-407 (P-407) in rats and different fractions of MEACL (n-hexane, chloroform, n-butanol, ethyl acetate (EA), water, and chloroform) were orally administered. Cholesterol and triglycerides were determined at 0, 12, 24, and 48h and LDL-C, vLDL-C, HDL-C, lipid peroxidation (LPO) and antioxidants were assayed after 48h. The expression of ABCA1, ABCG5, ABCG8, LDL-R, SREBP-1, and SREBP-2 and the activity of HMG-CoA reductase were assayed in the liver of P-407-administered rats treated with the EA fraction. Results: The in vitro data revealed potent radical-scavenging activities of MEACL fractions with the most potent effect showed by the EA fraction that also suppressed the activities of HMG-CoA reductase and PL. In P-407-induced hyperlipidemic rats, all fractions prevented dyslipidemia as shown by the decrease in total cholesterol, triglycerides, LDL-C, vLDL-C and atherogenic index. MEACL and its fractions prevented LPO and boosted GSH, superoxide dismutase, glutathione peroxidase, and catalase in P-407-administered rats. The EA fraction showed more effective anti-hyperlipidemic and antioxidant effects than other fractions and downregulated SREBP-2 while upregulated ABCA1 and LDL-R and ameliorated LPL and HMG-CoA reductase in hyperlipidemic rats. Conclusion: MEACL showed in vitro and in vivo antioxidant activity and the EA fraction significantly ameliorated dyslipidemia in a rat model of P-407-induced acute hyperlipidemia by modulating LPL, PL, HMG-CoA reductase, and cholesterolgenesis-related factors. Therefore, the leaves of A. carambola represent a safe alternative for the star fruit particularly in kidney disease patients, and the EA is the most effective anti-hyperlipidemic and antioxidant fraction.