Psoralea corylifolia L. extract ameliorates nonalcoholic fatty liver disease in free-fatty-acid-incubated HEPG2 cells and in high-fat diet-fed mice.
Nonalcoholic fatty liver disease (NAFLD) is a common chronic liver disease that is closely related to metabolic syndrome. We investigated the effect of a Psoralea corylifolia L. (PC) seeds extract (PCE) on NAFLD. PC seeds were extracted using different ethanol concentrations to produce five extracts, and the 70% ethanol PCE, which had the highest phenolic content, was used in subsequent in vitro and in vivo experiments. The inhibitory effect of PCE on hepatic steatosis was estimated using HepG2 cells treated with oleic acid (OA). In addition, an in vivo NAFLD model was established using high-fat diet (HFD)-induced obese C57BL/6 mice. Obesity was induced in mice over 14 weeks. PCE (100 or 200 mg/kg/day) was administered orally to mice after 8 weeks of the 14-week treatment period for 6 weeks. PCE suppressed lipid accumulation in OA-treated HepG2 cells. PCE ameliorated the antioxidant activity suppressions induced by the HFD. In addition, both PCE100 and PCE200 groups reduced lipid accumulation and the expression levels of inflammatory proteins as compared with HFD group. PCE administration significantly attenuated hepatic steatosis in liver tissues by decreasing the expression of lipogenic protein sterol regulatory element binding protein 1-c (SREBP-1c) and its downstream protein fatty acid synthase (FAS) in HFD-fed mice and in OA-treated HepG2 cells. Furthermore, PCE administration increased the phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase. These results suggest that PCE could be used as a functional material to prevent or ameliorate NAFLD by inhibiting lipid accumulation in liver. PRACTICAL APPLICATION: Psoralea corylifolia L. is rich in polyphenol and other phytochemicals. In this study, we identified the beneficial effects of Psoralea corylifolia L. extract on hepatic steatosis in oleic-acid-induced HepG2 cells and high-fat diet-fed mice. The result of this study will provide the evidence that a Psoralea corylifolia L. extract has potential use as a functional material for the prevention and amelioration of nonalcoholic fatty liver disease.
Hong Y
,Choi SI
,Hong E
,Kim GH
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Lycopus lucidus Turcz. ex Benth. Attenuates free fatty acid-induced steatosis in HepG2 cells and non-alcoholic fatty liver disease in high-fat diet-induced obese mice.
Non-alcoholic fatty liver disease (NAFLD) is closely related to metabolic diseases such as obesity and insulin resistance.
We studied whether an ethanol extract of Lycopus lucidus Turcz. ex Benth (LLE) exhibited effects on lipid metabolism in NAFLD.
An in vitro modelwas established by treatment of HepG2 cells with a 1 mM free fatty acid (FFA) mixture (oleic acid/palmitic acid, 2:1). C57BL/6 mice were fed a high-fat diet (HFD; 60 kcal% fat) for 14 weeks to induce obesity and were treated with or without LLE (100 or 200 mg/kg daily by oral gavage).
HepG2 cells were exposed to 1 mM FFA, with or without LLE (250 - 1000 mg/ml). Intracellular lipid contents were measured by Oil Red O staining and a Nile Red assay. The body weight, relative liver weight, hepatic lipids, triglycerides (TGs), and total cholesterol (TC) were measured in the mice. Serum alanine aminotransferase (ALT), TG, TC, glucose, insulin, leptin, and tumor necrosis factor-alpha (TNF-α) levels were determined by biochemical or enzyme-linked immunosorbent assays. Histologic analysis was performed in the liver. Western blotting and quantitative real-time polymerase chain reaction were used to analyze the expression of key enzymes of hepatic lipid metabolism.
LLE significantly decreased the intracellular lipid accumulation in FFA-treated HepG2 cells. LLE not only remarkably decreased the expression of lipogenesis genes but also increased β-oxidation in FFA-induced HepG2 cells. In the in vivo study, LLE treatment significantly decreased the body weight, relative liver weight, serum ALT, TC, and low-density lipoprotein cholesterol, as well as the serum glucose, insulin, leptin, and TNF-α levels in HFD-fed mice. The hepatic TG and TC contents were significantly reduced in the LLE-treated groups. Western blot analysis showed that the expression of sterol-regulatory element-binding protein 1 decreased, while that of phosphorylated AMP-activated protein kinase and peroxisome proliferator-activated receptor α increased in the LLE-treated mice.
These results suggest that LLE may exert protective effects against NAFLD-related obesity and metabolic disease.
Lee MR
,Yang HJ
,Park KI
,Ma JY
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Kangtaizhi Granule Alleviated Nonalcoholic Fatty Liver Disease in High-Fat Diet-Fed Rats and HepG2 Cells via AMPK/mTOR Signaling Pathway.
Kangtaizhi granule (KTZG) is a Chinese medicine compound prescription and has been proven to be effective in nonalcoholic fatty liver disease (NAFLD) treatment clinically. However, the underlying mechanisms under this efficacy are rather elusive. In the present study, network pharmacology and HPLC analysis were performed to identify the chemicals of KTZG and related target pathways for NAFLD treatment. Network pharmacology screened 42 compounds and 79 related targets related to NAFLD; HPLC analysis also confirmed six compounds in KTZG. Further experiments were also performed. In an in vivo study, SD rats were randomly divided into five groups: control (rats fed with normal diet), NAFLD (rats fed with high-fat diet), and KTZG 0.75, 1.5, and 3 groups (NAFLD rats treated with KTZG 0.75, 1.5, and 3 g/kg, respectively). Serum lipids were biochemically determined; hepatic steatosis and lipid accumulation were evaluated with HE and oil red O staining. In an in vitro study, HepG2 cells were incubated with 1 mM FFA to induce lipid accumulation with or without KTZG treatment. MTT assay, intracellular TG level, oil red O staining, and glucose uptake in cells were detected. Western blotting and immunohistochemical and immunofluorescence staining were also performed to determine the expression of lipid-related genes PPAR-γ, SREBP-1, p-AKT, FAS, and SIRT1 and genes in the AMPK/mTOR signaling pathway. In high-fat diet-fed rats, KTZG treatment significantly improved liver organ index and serum lipid contents of TG, TC, LDL-C, HDL-C, ALT, and AST significantly; HE and oil red O staining also showed that KTZG alleviated hepatic steatosis and liver lipid accumulation. In FFA-treated HepG2 cells, KTZG treatment decreased the intracellular TG levels, lipid accumulation, and attenuated glucose uptake significantly. More importantly, lipid-related genes PPAR-γ, SREBP-1, p-AKT, FAS, and SIRT1 expressions were ameliorated with KTZG treatment in high-fat diet-fed rats and FFA-induced HepG2 cells. The p-AMPK and p-mTOR expressions in the AMPK/mTOR signaling pathway were also modified with KTZG treatment in high-fat diet-fed rats and HepG2 cells. These results indicated that KTZG effectively ameliorated lipid accumulation and hepatic steatosis to prevent NAFLD in high-fat diet-fed rats and FFA-induced HepG2 cells, and this effect was associated with the AMPK/mTOR signaling pathway. Our results suggested that KTZG might be a potential therapeutic agent for the prevention of NAFLD.
Zhang J
,Du H
,Shen M
,Zhao Z
,Ye X
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Honokiol activates the LKB1-AMPK signaling pathway and attenuates the lipid accumulation in hepatocytes.
Honokiol is a bioactive neolignan compound isolated from the species of Magnolia. This study was designed to elucidate the cellular mechanism by which honokiol alleviates the development of non-alcoholic steatosis. HepG2 cells were treated with honokiol for 1h, and then exposed to 1mM free fatty acid (FFA) for 24h to simulate non-alcoholic steatosis in vitro. C57BL/6 mice were fed with a high-fat diet for 28days, and honokiol (10mg/kg/day) was daily treated. Honokiol concentration-dependently attenuated intracellular fat overloading and triglyceride (TG) accumulation in FFA-exposed HepG2 cells. These effects were blocked by pretreatment with an AMP-activated protein kinase (AMPK) inhibitor. Honokiol significantly inhibited sterol regulatory element-binding protein-1c (SREBP-1c) maturation and the induction of lipogenic proteins, stearoyl-CoA desaturase-1 (SCD-1) and fatty acid synthase (FAS) in FFA-exposed HepG2 cells, but these effects were blocked by pretreatment of an AMPK inhibitor. Honokiol induced AMPK phosphorylation and subsequent acetyl-CoA carboxylase (ACC) phosphorylation, which were inhibited by genetic deletion of liver kinase B1 (LKB1). Honokiol stimulated LKB1 phosphorylation, and genetic deletion of LKB1 blocked the effect of honokiol on SREBP-1c maturation and the induction of SCD-1 and FAS proteins in FFA-exposed HepG2 cells. Honokiol attenuated the increases in hepatic TG and lipogenic protein levels and fat accumulation in the mice fed with high-fat diet, while significantly induced LKB1 and AMPK phosphorylation. Taken together, our findings suggest that honokiol has an anti-lipogenic effect in hepatocytes, and this effect may be mediated by the LKB1-AMPK signaling pathway, which induces ACC phosphorylation and inhibits SREBP-1c maturation in hepatocytes.
Seo MS
,Kim JH
,Kim HJ
,Chang KC
,Park SW
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