Oleic Acid-induced HepG2 Cells Research Articles

Eriodictyol regulates white adipose tissue browning and hepatic lipid metabolism in high fat diet-induced obesity mice via activating AMPK/SIRT1 pathway

Ethnopharmacological relevanceBlossom of Citrus aurantium L. var. amara Engl. (CAVA) has been popularly consumed as folk medicine and dietary supplement owing to its various beneficial effects and especially anti-obesity potential. Our previous study predicted that eriodictyol was probably one of the key active compounds of the total flavonoids from blossom of CAVA. However, effects of eriodictyol in anti-obesity were still elusive. Aim of the studyThis study was performed to explore the precise role of eriodictyol in white adipose tissue (WAT) browning and hepatic lipid metabolism, and simultaneously, to verify the impact of eriodictyol on the total flavonoids of CAVA in losing weight. Materials and methodsThe pancreas lipase assay was conducted and oleic acid-induced HepG2 cells were established to preliminarily detect the lipid-lowering potential of eriodictyol. Then, high fat diet-induced obesity (DIO) mouse model was established for in vivo studies. The biochemical indicators of mice were tested by commercial kits. The histopathological changes of WAT and liver in mice were tested by H&E staining, Oil Red O staining and Sirius Red staining. Immunohistochemical, western blot assay, as well as RT-qPCR analysis were further performed. Additionally, molecular docking assay was used to simulate the binding of eriodictyol with potential target proteins. ResultsIn vitro studies showed that eriodictyol intervention potently inhibited pancreatic lipase activity and reversed hepatic steatosis in oleic acid-induced HepG2 cells. Consistently, long-term medication of eriodictyol also effectively prevented obesity and improved lipid and glucose metabolism in diet-induced obesity (DIO) mice. Obesity-induced histopathological changes in iWAT, eWAT and BAT, and abnormal expression levels of IL-10, IL-6 and TNF-α in iWAT of DIO mice were also significantly reversed by eriodictyol treatment. Eriodictyol administration significantly and potently promoted browning of iWAT by increasing expression levels of thermogenic marker protein of UCP1, as well as brown adipocyte-specific genes of PGC-1α, SIRT1 and AMPKα1. Further assays revealed that eriodictyol enhanced mitochondrial function, as shown by an increase in compound IV activity and the expression of tricarboxylic acid cycle-related genes. Besides, eriodictyol addition markedly reversed hepatic damages and hepatic inflammation, and enhanced hepatic lipid metabolism in DIO mice, as evidenced by its regulation on p-ACC, CPT1-α, UCP1, PPARα, PGC-1α, SIRT1 and p-AMPKα expression. Molecular docking results further validated that AMPK/SIRT1 pathway was probably the underlying mechanisms by which eriodictyol acted. ConclusionEriodictyol exhibited significant anti-obesity effect, which was comparable to that of the total flavonoids from blossom of CAVA. These findings furnished theoretical basis for the application of eriodictyol in weight loss.

Chlorogenic Acid and its Isomers Attenuate NAFLD by Mitigating Lipid Accumulation in Oleic Acid-Induced HepG2 Cells and High-Fat Diet- Fed Zebrafish.

Chlorogenic acid (Chl), isochlorogenic acid A (Isochl A), and isochlorogenic acid B (Isochl B) are naturally occurring phenolic compounds, which have been shown to exert a regulatory effect on lipid metabolism. However, the mechanism underlying this effect remains unclear. Herein, we investigated the inhibitory effects and underlying mechanisms of these three phenolic compounds on oleic acid (OA)-induced HepG2 cells and high-fat diet (HFD)-fed zebrafish. Lipid accumulation and triacylglycerol levels increased in OA-induced cells, which was attenuated by Chl, Isochl A, and Isochl B. Moreover, the levels of malondialdehyde (MDA) and reactive oxygen species (ROS) decreased, while superoxide dismutase (SOD) levels increased by Chl, Isochl A and Isochl B treatment. Western blot analysis demonstrated that Chl, Isochl A and Isochl B reduced the expression of lipogenesis-related protein, including fatty acid synthase (FAS), acetyl-CoA carboxylase (ACC) and peroxisome proliferator-activated receptor gamma (PPARγ). Moreover, peroxisome proliferator-activated receptor alpha gamma (PPARα) was increased by Chl, Isochl A, and Isochl B treatment. In addition, our results indicated that Chl, Isochl A and Isochl B decreased lipid profiles and lipid accumulation in HFD-fed zebrafish. Thus, these findings highlight the potential of Chl, Isochl A, and Isochl B as effective agents for treating or/and ameliorating non-alcoholic fatty liver disease (NAFLD).

Effects of Crataegus orientalis fruit extract on lipid accumulation in oleic acid-induced HepG2 cells

Effects of Crataegus orientalis fruit extract on lipid accumulation in oleic acid-induced HepG2 cells

UPLC-Q-TOF-MS Analysis of Chemical Constituents of the Kadsura coccinea Extract with Effect of Attenuating Lipid Accumulation in Vitro

Objective/Background: This study aims to explore the Kadsura coccinea extract (KCE)'s effect on lipid accumulation in vitro and its chemical components characterizations, aiming at developing a new alternative plant medicinal resource to fight against non-alcoholic fatty liver disease (NAFLD). Methods: After toxicological evaluation of KCE on HepG2 cells, Oil red O staining model and intracellular TGs quantification kit were used to examine the effects of KCE on lipid accumulation in vitro. The chemical components characterizations and potential active chemical constituents of the bioactive KCE were analyzed using ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) technology. Results: Among the chosen non-toxic concentrations of KCE (5, 10, 20 μg/mL), KCE can reduce the number and volume of lipid droplets in the oleic acid induced HepG2 cells in a dose-dependent manner, and the results of TGs quantification were almost consistent with the results of the oil red O staining experiment. These data indicate the KCE has ameliorative effect on lipid accumulation in vitro. In addition, a total of 26 compounds from the KCE were tentatively identified, dibenzocyclooctadiene lignans (DCLs) including Kadsulignan L and Gomisin J could be the main supposed components. Conclusion: These findings support further investigation into Kadsura coccinea containing DCLs as a new alternative medicinal arsenal to battle against NAFLD.

An extended strategy of “Recursive Tree” for characterization of drug metabolites in vivo and in vitro and actional mechanism study based on network Pharmacology: Formononetin as a study case

The screening and identification of drug metabolites in biological matrices is challenging, and ultra-high performance liquid chromatography-Q-Exactive Orbitrap mass spectrometry (UHPLC-Q-Exactive Orbitrap MS) has become a powerful technological tool for drug metabolites analysis due to its high sensitivity. However, the spectral information contained in existing chemical standards and databases is very limited, and the UHPLC-Q-Exactive Orbitrap MS technique alone cannot satisfy the identification of complex and diverse metabolites. Therefore, there is an urgent need for a new strategy to achieve comprehensive drug metabolic profile. Based on this, we have innovatively constructed a “recursive tree” analysis strategy and bridged it with network pharmacology for elucidating the pharmacological mechanisms of drugs. In this paper, we investigated the overall metabolic profile of formononetin as an example and utilized the primary branching metabolites of formononetin as effective ingredients for the study of the anti-NAFLD mechanism. The results showed that a total of 131 metabolites (prototype drug included) were detected and identified. Among them, 106 metabolites were found in rats and 31 metabolites were found in liver microsomes. Glucose conjugation, demethylation, sulfation, glucuronidation, and their complex reactions were the major processes of formononetin biotransformation. Network pharmacology results screened 104 potential targets and 20 major signaling pathways. Their mechanisms may be additive and/or synergistic effects. In addition, the therapeutic effects of formononetin against NAFLD were investigated based on palmitic acid / oleic acid-induced HepG2 cells. In summary, the recursive tree analysis strategy provides a convenient method for the identification of metabolites, and its seamless integration with network pharmacology lays the foundation for studying the pharmacological activities of natural products.

Probiotic-fermented tomato with hepatic lipid metabolism modulation effects: analysis of physicochemical properties, bioactivities, and potential bioactive compounds.

Lactiplantibacillus plantarum NCUH001046 (LP)-fermented tomatoes exhibited the potential to alleviate obesity in our previous study. This subsequent study further delves deeper into the effects of LP fermentation on the physicochemical properties, bioactivities, and hepatic lipid metabolism modulation of tomatoes, as well as the analysis of potential bioactive compounds exerting obesity-alleviating effects. Results showed that after LP fermentation, viable bacterial counts peaked at 9.11 log CFU mL-1 and sugar decreased, while organic acids, umami amino acids, total phenols, and total flavonoids increased. LP fermentation also improved the inhibition capacities of three digestive enzyme activities and Enterobacter cloacae growth, as well as antioxidant activities. Western blot results indicated that fermented tomatoes, especially live probiotic-fermented tomatoes (LFT), showed improved effects compared to unfermented tomatoes in reducing hepatic lipid accumulation by activating the AMPK signal pathway. UHPLC-Q-TOF/MS-based untargeted metabolomics analysis showed that chlorogenic acid, capsiate, tiliroside, irisflorentin, and homoeriodictyol levels increased after fermentation. Subsequent cell culture assays demonstrated that irisflorentin and homoeriodictyol reduced lipid accumulation via enhancing AMPK expression in oleic acid-induced hyperlipidemic HepG2 cells. Furthermore, Spearman's correlation analysis indicated that the five phenols were positively associated with hepatic AMPK pathway activation. Consequently, it could be inferred that the five phenols may be potential bioactive compounds in LFT to alleviate obesity and lipid metabolism disorders. In summary, these findings underscored the transformative potential of LP fermentation in enhancing the bioactive profile of tomatoes and augmenting its capacity to alleviate obesity and lipid metabolism disorders. This study furnished theoretical underpinnings for the functional investigation of probiotic-fermented plant-based foods.

Korean red ginseng formula attenuates non-alcoholic fatty liver disease in oleic acid-induced HepG2 cells and high-fat diet-induced rats

ObjectiveNon-alcoholic fatty liver disease (NAFLD) is the leading chronic liver disease. We have developed a Korean Red Ginseng Formula (KRGF) containing extracts of Korean Red Ginseng (KRG), Crataegus Fructus, and Cassiae Semen. In this study, our aims were to investigate the therapeutic potential and underpinning mechanisms of KRGF in NAFLD complicated by hyperlipidemia. MethodsIn the in vitro assays, HepG2 cells were treated with KRGF for 24 h in the presence or absence of oleic acid (OA). To assess the in vivo protective effect of KRGF against NAFLD, rats fed a high-fat diet (HFD) were given intragastric administration for 30 days. ResultsKRGF exerted protective effects against NAFLD by reducing lipid accumulation and steatosis in OA-stimulated HepG2 cells and HFD-fed rats. In HFD-fed rats, KRGF effectively decreased triglyceride levels in both blood and liver tissue and modulated the expression of key regulators of lipogenesis and fatty acid oxidation. KRGF downregulated the expression of lipogenesis factors, namely C/EBPα, FAS, SREBP-1c, and PPARγ, while upregulating the expression of PPARα and CPT-1, thus promoting fatty acid oxidation. Additionally, KRGF intensified the phosphorylation of AMPK and ACC, which are two enzymes that suppress fatty acid synthesis and promote fatty acid oxidation. KRGF effectively decreased total cholesterol (TC) levels in both blood and liver tissue, and it modulated the expression of major enzymes related to TC metabolism, namely apoB, ACAT2, CYP7A1, and HMGCR. ConclusionIn conclusion, KRGF mitigated NAFLD complicated by hyperlipidemia by modulating triglyceride and cholesterol metabolism, suggesting its potential for future development in the treatment of NAFLD.

Polyphenolic compounds from Idesia polycarpa Maxim. fruits ameliorate non-alcoholic fatty liver disease by modulating lipid metabolism in oleic acid-induced HepG2 cells and high-fat diet-induced mice

Previous reports have suggested that Idesia polycarpa Maxim. (I. polycarpa) fruits possess properties for the prevention and treatment of non-alcoholic fatty liver disease (NAFLD), owing to its lipid-lowering and anti-oxidant activities. In this study, ethyl acetate extract (EAE) of I. polycarpa fruits supplementation reduced body weight gain and inflammatory cytokines secretion, improved glucose tolerance and insulin sensitivity, and alleviated hepatic steatosis in high-fat diet (HFD)-fed mice. Of note, a total of eight polyphenolic compounds were isolated and identified from EAE, among which 1-[(6′-O-(Z)-p-coumar-oyl)-β-D-glucopyranosyl]-oxy-2-phenol (compound 2) exhibited better lipid-lowering activity in oleic acid (OA)-induced HepG2 cells than other compounds. Moreover, using hepatic steatosis cell model and PPAR-luciferase reporter system, we found that compound 2 reduced lipid accumulation and lipotoxicity, and inhibited inflammatory reaction via the PPAR-α-mediated improvement of lipid metabolism. This experiment will provide a theoretical basis for intervention with I. polycarpa fruits in delaying the occurrence and development of NAFLD.

Kaempferol attenuates nonalcoholic fatty liver disease in type 2 diabetic mice via the Sirt1/AMPK signaling pathway

Nonalcoholic fatty liver disease (NAFLD) is one of the most common liver diseases with limited treatment options. Moreover, its prevalence is doubled in type 2 diabetes mellitus (T2DM). Kaempferol (KAP) is a flavonoid compound that has been suggested to have beneficial effects on NAFLD, but studies on the mechanism are lacking, especially in the diabetic state. Herein, we investigated the effect of KAP on NAFLD associated with T2DM and its underlying mechanism in vitro and in vivo. The results of in vitro studies indicated that KAP treatment (10−8–10−6 M) significantly reduced lipid accumulation in oleic acid-induced HepG2 cells. Moreover, in the T2DM animal model of db/db mice, we confirmed that KAP (50 mg/kg) significantly reduced lipid accumulation and improved liver injury. Mechanistic studies in vitro and in vivo showed that Sirtuin 1 (Sirt1)/AMP-activated protein kinase (AMPK) signal was involved in KAP regulation of hepatic lipid accumulation. KAP treatment activated Sirt1 and AMPK, upregulated the levels of fatty acid oxidation-related protein proliferator activated receptor gamma coactivator 1α (PGC1α); and downregulated lipid synthesis-related proteins, including acetyl-coA carboxylase (ACC), fatty acid synthase (FASN), and sterol regulatory element-binding protein 1 (SREBP1). Furthermore, the curative effect of KAP on lipid accumulation was abolished by siRNA-mediated knockdown of either Sirt1 or AMPK. Collectively, these findings suggest that KAP may be a potential therapeutic agent for NAFLD associated with T2DM by regulating hepatic lipid accumulation through activation of Sirt1/AMPK signaling.

A novel small molecule AdipoR2 agonist ameliorates experimental hepatic steatosis in hamsters and mice.

Adiponectin receptor 2 (AdipoR2) can be activated by its endogenous ligand adiponectin to reduce hepatic steatosis, and is regarded as a therapeutic target for metabolic associated fatty liver disease (MAFLD). This study proposes a novel anthraquinone compound, emodin succinate monoethyl ester (ESME), which activates AdipoR2, inhibits hepatic lipogenesis, promotes fatty acid oxidation, and alleviates experimental hepatic steatosis in hamsters and mice. Molecular docking shows that ESME has strong binding potential with AdipoR2 by forming a arene-arene interaction. AdipoR2 on the cytomembrane of HepG2 cells can be labeled by fluorescent ESME (Cy5-ESME). ESME activates AdipoR2, AMPK and PPARα, and reduces lipid deposition in palmitic acid or oleic acid-induced HepG2 and L02cells. Suppression of AdipoR2 expression or AMPK activation completely eliminates the effect of ESME on reducing lipid accumulation in hepatocytes. Oral administration of ESME reduces liver lipid production and accumulation, and alleviates hepatic steatosis in hamsters and Apoe-/- mice induced by high-fat diet. Compared with statins and emodin, ESME showed prepotent efficacy and safety in reducing hepatic steatosis and protecting hepatocytes. Furthermore, ESME activates CaMKK2 and LKB1 in liver to activate AMPK and reduce lipogenesis through stimulating AdipoR2. Taken together, ESME reduces hepatic lipid accumulation and alleviates hepatic steatosis by agonizing AdipoR2. ESME is a promising new agent for clinical treatment of MAFLD.

Structural characterization of polysaccharides from Medicago sativa L. roots and lipid-lowering activity in oleic acid-induced HepG2 cells

Polysaccharides have multiple pharmacological activities without toxicity or side effects. In the present study, the structure, antioxidant and lipid-lowering activities of alfalfa (Medicago sativa L.) polysaccharides (APS) were reported. Three alfalfa root polysaccharides (RAPS), RAPS-1, RAPS-2, and RAPS-3 were isolated, purified, and characterized. The structural analyses demonstrated that the homogeneous RAPS had molecular weights of 22.60, 26.95, and 38.25 kDa, respectively. Furthermore, RAPS-1 was composed of rhamnose, arabinose, xylose, glucuronic acid, glucose, and galactose with molar ratios of 10.25%, 12.53%, 6.58%, 4.56%, 15.74%, and 36.30%, RAPS-2 comprised rhamnose, arabinose, xylose, glucose, and galactose in the molar ratios of 24.07%, 14.48%, 1.24%, 15.05%, and 39.37%, while RAPS-3 was composed of rhamnose, arabinose, xylose, glucuronic acid, mannose, glucose, and galactose in the molar ratios of 31.61%, 11.78%, 1.93%, 5.49%, 3.18%, 14.56%, and 24.63%. The SEM analysis suggested that with the increase of the molecular weight of polysaccharides, its structure is more compact and the stability is stronger. In vitro, RAPS showed strong scavenging ability against DPPH and ABTS free radicals. In addition, RAPS had potent antioxidant activity and reduced the accumulation of lipids in oleic acid-induced NAFLD in HepG2 cells, with RAPS-1 being the most effective. Furthermore, RAPS-1 decreased MDA production, improved the activities of SOD and the total antioxidant capacity of cells, demonstrating that RAPS could effectively restrict lipid accumulation in HepG2 cells induced by oleic acid by restoring the antioxidant system. Western blot analysis indicated that the RAPS-1 can activate the Nrf2/HO-1 signaling pathway to relieve oxidative stress induced by oleic acid, thus playing a role in the treatment of NAFLD.

Hypolipidemic effects of macadamia oil are related to AMPK activation and oxidative stress relief: In vitro and in vivo studies

Macadamia oil is rich in monounsaturated fatty acids, especially a high level of palmitoleic acid, which may have beneficial health effects by lowering blood lipid levels. In our study, the hypolipidemic effects of macadamia oil and its potential mechanisms of action were investigated using a combination of in vitro and in vivo assays. The results showed that macadamia oil significantly reduced lipid accumulation, and improved triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) levels in oleic acid-induced high-fat HepG2 cells. The macadamia oil treatment also exhibited antioxidant effects, as seen by its ability to reduce reactive oxygen species and malondialdehyde (MDA) levels, and increase superoxide dismutase (SOD) activity. The effects of 1000 μg/mL of macadamia oil were comparable to that of 4.19 μg/mL simvastatin. The results of qRT-PCR and western blotting analyses indicated that macadamia oil effectively inhibited hyperlipidemia by reducing the expression levels of SREBP-1c, PPAR-γ, ACC and FAS and by enhancing the expression levels of HO-1, NRF2 and γ-GCS, via AMPK activation and oxidative stress relief, respectively. In addition, different doses of macadamia oil were found to significantly improve liver lipid accumulation, reduce serum and liver TC, TG, and LDL-C levels, increase HDL-C levels, increase antioxidant enzyme (SOD, GSH-Px, and T-AOC) activity, and decrease the MDA content of mice on a high-fat diet. These results indicated that macadamia oil had a hypolipidemic effect and provide insights that might facilitate the development of functional food and dietary supplements.

Fabrication, characterization, and lipid-lowering effects of naringenin-zein-sodium caseinate-galactosylated chitosan nanoparticles

Naringenin is a natural flavonoid that is widely distributed in citrus fruits and pharmacologically demonstrated to licit lipid-lowering activity. However, the clinical relevance of naringenin is limited due to its poor water solubility and inefficient absorption. In this study, we designed and developed naringenin-zein-sodium caseinate-galactosylated chitosan nanoparticles (GC-NPs) for hepatocyte-specific targeting, with naringenin-zein-sodium caseinate-chitosan nanoparticles (CS-NPs) as a control. Electrostatic adsorption was the primary binding mode in the GC-NPs and CS-NPs. Moreover, the particle size and zeta potential of GC-NPs were larger than those of CS-NPs and both types of nanoparticles had similar encapsulation rates. In vitro study experiments demonstrated that GC-NPs aggregated inside and outside of the cell membrane and significantly inhibited total triglyceride and cholesterol levels in oleic acid-induced HepG2 cells (p < 0.05). In high-fat diet-fed C57BL/6J mice, GC-NPs administration visibly improved the body weight, total cholesterol, and triglyceride content in the serum and liver, and high-density lipoprotein cholesterol levels improved, which corresponded to liver histological results. Additionally, in vitro and in vivo assays demonstrated that GC-NPs exhibited higher lipid-lowering activity than CS-NPs and naringenin monomers. These results suggest that GC-NPs are effective for oral delivery of naringenin in lipid-lowering therapies.

Rutaecarpin reduces lipids by DGKθ-dependent activation of PPARα.

Lipid metabolic disorders pose a serious threat to human health, and currently no good treatments exist. In earlier studies by the authors, HepG2 cells with diacylglycerol kinase theta (DGKθ) knockout were found to cause significant lipid accumulation, suggesting that DGKθ may be a potential target for treating lipid metabolic disorders. A high-throughput screeningof natural products targeting the potential signaling pathway of lipid metabolism was carried out in the DGKθ-T2A-luciferase knock-in HepG2 cell. RNA-sequencingand bioinformatic approaches were used to analyze the potential pathway by which rutaecarpin decreases lipids. Western blot and quantitative polymerase chain reactionwere performed to investigate the mechanisms of rutaecarpin's reduction in lipid levels. Rutaecarpin was found to significantly enhance DGKθ expression, and the potential mechanisms by which rutaecarpin accelerates lipid metabolism by targeting DGKθ was explored in vitro and in vivo. The results indicated that rutaecarpin could markedly reduce lipid accumulation in oleic acid-induced HepG2 cells and in high-fat diet-induced obese C57BL/6J mice by targeting the hepatocyte nuclear factor 1-beta (HNF1B)-DGKθ-peroxisome proliferator-activated receptor alpha (PPARα)-apolipoprotein C3 (APOC3) pathway. Rutaecarpin is effective in reducing lipid accumulation, and the development of a high-throughput screening platform based on a reporter knock-in cell line may facilitate the discovery of effective drugs for lipid metabolic disorders based on the DGKθ target.

고당 및 올레산으로 유도된 HepG2 세포에서 국내산 호두(Juglans regia) 추출물의 비알코올성 지방간 질환 개선 효과

This study was investigated to evaluate the in vitro anti-diabetic activity and lipid accumulation inhibitory effect of the domestic walnut (Junglans regia, Gimcheon 1ho cultivar) in high glucose- and oleic acid-induced hepatic HepG2 cells. Eighty percent of ethanolic extract from Gimcheon 1ho (GC) showed higher inhibitory effects against α-amylase and α-glucosidase activities when compared to other ethanolic extracts. GC significantly inhibited the formation of advanced glycation end products (AGEs). The GC increased cell viability against H2O2- and high glucose-induced cell death determined by 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. GC reduced the formation of reactive oxygen species (ROS) in H2O2- and high glucose-induced HepG2 cells determined by 2’,7’-dichlorofluorescein diacetate (DCF-DA) assay. GC inhibited lipid accumulation in the oleic acid-induced HepG2 cells. The GC increased AMP-activated protein kinase (AMPK) phosphorylation and decreased the expression of lipid metabolism related proteins such as sterol regulatory element-binding proteins 1 (SREBP-1), fatty acid synthase (FAS), sterol regulatory element-binding protein 2 (SREBP-2) and 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMGCR). The results suggest GC is a potentially functional food material which can improve nonalcoholic fatty liver disease by inhibiting lipid accumulation.

Hederagenin Exerts Potential Antilipemic Effect via p38MAPK Pathway in Oleic Acid-induced HepG2 cells and in Hyperlipidemic Rats.

Hederagenin, a natural compound distributed in many medicinal plants, has a variety of pharmacological properties including anti-bacteria, anti-inflammation, anti-oxidation, and anti- apoptosis.. The aim of this study was to evaluate the effects of hederagenin on decreasing blood lipid and anti-oxidative stress in oleic acid-induced HepG2 cells and hyperlipidemic rats, and explore underlying mechanisms. In vitro, TG was used as the index to verify the lipid-lowering effect of hederagenin in oleic acid-induced HepG2 cells. In vivo, TC, TG, LDL-C, and HDL-C were used as direct indicators to study the antilipemic effect of hederagenin in hyperlipidemic rats. MDA, SOD, and GSH-PX were measured to analyze the anti-oxidative effect of hederagenin. The signaling pathways of anti-oxidation were evaluated using Western blot. Our results showed that hederagenin (250μmol/L) increased significantly TG clearance rate. In addition, treatment with hederagenin, XZK and simvastatin reduced effectively TC, TG, LDL-C and MDA content, and increased HDL-C, SOD and GSH-PX in HFD rats. Moreover, the phosphorylation level of p38 MAPK was inhibited after administration of hederagenin, XZK and simvastatin. Our results revealed that hederagenin possessed beneficial potentials for hypolipidemic effects, especially in TG clearance. The mechanism might be associated with inhibition of lipid absorption, reduction of lipid oxidation, and down-regulation of p38MAPK phosphorylation.

Kaempferol prevents the progression from simple steatosis to non-alcoholic steatohepatitis by inhibiting the NF-κB pathway in oleic acid-induced HepG2 cells and high-fat diet-induced rats

Currently, non-alcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide, and more functional foods are needed for NAFLD prevention and treatment. Kaempferol can be obtained from tea, broccoli, propolis, grapefruit and other green plants. However, relatively systematic studies concerning the preventative effects of kaempferol against NAFLD are lacking. In this study, using network pharmacological methods, we found that kaempferol could prevent the development of NAFLD by targeting multiple targets; for instance, kaempferol suppressed inflammation, improved insulin resistance and reduced oxidative stress. Furthermore, we confirmed that kaempferol could suppress inflammatory responses and prevent the development of NAFLD in vitro and in vivo by inhibiting the nuclear transcriptional activity of NF-κB. Our study supports the use of kaempferol as a functional food or dietary supplement for NAFLD prevention and treatment. In addition, this study could be beneficial for understanding the anti-NAFLD mechanism of many other flavonoids.

Lily bulbs' polyphenols extract ameliorates oxidative stress and lipid accumulation in vitro and in vivo.

Polyphenols have the potential to reduce the risk of many metabolic disorders. Lily bulbs are rich in polyphenols; however, their effects on lipid metabolism remain unclear. This study aimed to explore the effects of lily bulbs' polyphenols (LBPs) on oxidative stress and lipid metabolism. A total of 14 polyphenolic compounds in LBPs were identified by high-performance liquid chromatography equipped with diode-array detection mass spectrometry. Total phenolic compound in LBPs was 53.76 ± 1.12g kg-1 dry weight. In cellular experiments, LBPs attenuated the disruption of mitochondrial membrane potential, impeded reactive oxygen species production, alleviated oxidative stress, and reduced lipid accumulation in oleic acid induced HepG2 cells. In in vivo studies, LBPs significantly inhibited body weight gain, reduced lipid levels in serum and liver, and improved oxidative damage in a dose-dependent manner in mice fed a high-fat diet. Moreover, LBPs ameliorated hepatic steatosis and suppressed the expression of hepatic-lipogenesis-related genes (SREBP-1c, FAS, ACC1, and SCD-1) and promoted lipolysis genes (SRB1 and HL) and lipid oxidation genes (PPARα and CPT-1) in mice fed a high-fat diet. It was concluded that LBPs are a potential complementary therapeutic alternative in the development of functional foods to curb obesity and obesity-related diseases, such as metabolic syndrome. © 2021 Society of Chemical Industry.

Hesperetin ameliorates hepatic oxidative stress and inflammation via the PI3K/AKT-Nrf2-ARE pathway in oleic acid-induced HepG2 cells and a rat model of high-fat diet-induced NAFLD.

Non-alcoholic fatty liver disease (NAFLD) is considered the most common liver disease. Dietary supplementation has become a promising strategy for managing NAFLD. Hesperetin, a citrus flavonoid, is mainly found in citrus fruits (oranges, grapefruit, and lemons) and possesses multiple pharmacological properties, including anti-cancer, anti-Alzheimer and anti-diabetic effects. However, the anti-NAFLD effect and mechanisms of hesperetin remain unclear. In this study, we investigated the therapeutic effect of hesperetin against NAFLD and the underlying mechanism in vitro and in vivo. In oleic acid (OA)-induced HepG2 cells, hesperetin upregulated antioxidant levels (SOD/GPx/GR/GCLC/HO-1) by triggering the PI3 K/AKT-Nrf2 pathway, alleviating OA-induced reactive oxygen species (ROS) overproduction and hepatotoxicity. Furthermore, hesperetin suppressed NF-κB activation and reduced inflammatory cytokine secretion (TNF-α and IL-6). More importantly, we revealed that this anti-inflammatory effect is attributed to reduced ROS overproduction by the Nrf2 pathway, as pre-treatment with Nrf2 siRNA or an inhibitor of superoxide dismutase (SOD) or/and glutathione peroxidase (GPx) abolished hesperetin-induced NF-κB inactivation and reductions in inflammatory cytokine secretion. In a rat model of high-fat diet (HFD)-induced NAFLD, we confirmed that hesperetin relieved hepatic steatosis, oxidative stress, inflammatory cell infiltration and fibrosis. Moreover, hesperetin activated the PI3 K/AKT-Nrf2 pathway in the liver, increasing antioxidant expression and inhibiting NF-κB activation and inflammatory cytokine secretion. In summary, our results demonstrate that hesperetin ameliorates hepatic oxidative stress through the PI3 K/AKT-Nrf2 pathway and that this antioxidative effect further suppresses NF-κB-mediated inflammation during NAFLD progression. Thus, our study suggests that hesperetin may be an effective dietary supplement for improving NAFLD by suppressing hepatic oxidative stress and inflammation.

Phloretin ameliorates hepatic steatosis through regulation of lipogenesis and Sirt1/AMPK signaling in obese mice

BackgroundPhloretin is isolated from apple trees and could increase lipolysis in 3T3-L1 adipocytes. Previous studies have found that phloretin could prevent obesity in mice. In this study, we investigated whether phloretin ameliorates non-alcoholic fatty liver disease (NAFLD) in high-fat diet (HFD)-induced obese mice, and evaluated the regulation of lipid metabolism in hepatocytes.MethodsHepG2 cells were treated with 0.5 mM oleic acid to induce lipid accumulation, and then treated with phloretin to evaluate the molecular mechanism of lipogenesis. In another experiment, male C57BL/6 mice were fed normal diet or HFD (60% fat, w/w) for 16 weeks. After the fourth week, mice were treated with or without phloretin by intraperitoneal injection for 12 weeks.ResultsPhloretin significantly reduced excessive lipid accumulation and decreased sterol regulatory element-binding protein 1c, blocking the expression of fatty acid synthase in oleic acid-induced HepG2 cells. Phloretin increased Sirt1, and phosphorylation of AMP activated protein kinase to suppress acetyl-CoA carboxylase expression, reducing fatty acid synthesis in hepatocytes. Phloretin also reduced body weight and fat weight compared to untreated HFD-fed mice. Phloretin also reduced liver weight and liver lipid accumulation and improved hepatocyte steatosis in obese mice. In liver tissue from obese mice, phloretin suppressed transcription factors of lipogenesis and fatty acid synthase, and increased lipolysis and fatty acid β-oxidation. Furthermore, phloretin regulated serum leptin, adiponectin, triglyceride, low-density lipoprotein, and free fatty acid levels in obese mice.ConclusionsThese findings suggest that phloretin improves hepatic steatosis by regulating lipogenesis and the Sirt-1/AMPK pathway in the liver.