A PPARγ, NF-κB and AMPK-dependent mechanism may be involved in the beneficial effects of curcumin in the diabetic db/db mice liver. Molecules. 2014;19:8289-8302. [PMID: 24945581 DOI: 10.3390/molecules19068289]

Strawberry Intake Ameliorates Oxidative Stress and Decreases GABA Levels Induced by High-Fat Diet in Frontal Cortex of Rats

It has been proposed that there is a correlation between high-fat diet (HFD), oxidative stress and decreased γ-aminobutyric acid (GABA) levels, but this has not been thoroughly demonstrated. In the present study, we determined the effects of strawberry extract intake on the oxidative stress and GABA levels in the frontal cortex (FC) of obese rats. We observed that an HFD increased lipid and protein oxidation, and decreased GABA levels. Moreover, UV-irradiated strawberry extract (UViSE) decreased lipid peroxidation but not protein oxidation, whereas non-irradiated strawberry extract (NSE) reduced protein oxidation but not lipid peroxidation. Interestingly, NSE increased GABA concentration, whereas UViSE was not as effective. In conclusion, our results suggest that an HFD increases oxidative damage in the FC, whereas strawberry extract intake may ameliorate the disturbances associated with HFD-induced oxidative damage.

Curcumin inhibits cigarette smoke-induced inflammation via modulating the PPARγ-NF-κB signaling pathway

The PPARγ-NF-κB signaling pathway is involved in the anti-inflammatory effect of curcumin on cigarette smoke-induced COPD models.

The Action of Polyphenols in Diabetes Mellitus and Alzheimer's Disease: A Common Agent for Overlapping Pathologies

Diabetes Mellitus (DM) and Alzheimer's disease (AD) are two prevalent diseases in modern societies, which are caused mainly by current lifestyle, aging and genetic alterations. It has already been demonstrated that these two diseases are associated, since individuals suffering from DM are prone to develop AD. Conversely, it is also known that individuals with AD are more susceptible to DM, namely type 2 diabetes (T2DM). Therefore, these two pathologies, although completely different in terms of symptomatology, end up sharing several mechanisms at the molecular level, with the most obvious being the increase of oxidative stress and inflammation. Polyphenols are natural compounds widely spread in fruits and vegetables whose dietary intake has been considered inversely proportional to the incidence of DM and AD. So, it is believed that this group of phytochemicals may have preventive and therapeutic potential, not only by reducing the risk and delaying the development of these pathologies, but also by improving brain's metabolic profile and cognitive function. The aim of this review is to understand the extent to which DM and AD are related pathologies, the degree of similarity and the relationship between them, to detail the molecular mechanisms by which polyphenols may exert a protective effect, such as antioxidant and anti-inflammatory effects, and highlight possible advantages of their use as common preventive and therapeutic alternatives.

AICAR-Induced AMPK Activation Inhibits the Noncanonical NF-κB Pathway to Attenuate Liver Injury and Fibrosis in BDL Rats

BACKGROUND

To evaluate the AMP-activated protein kinase- (AMPK-) mediated signaling and NF-κB-related inflammatory pathways that contribute to cholestatic diseases in the bile duct ligation (BDL) rat model of chronic cholestasis and verify the protective role of 5-Aminoimidazole-4-carboxamide1-β-D-ribofuranoside (AICAR) against hepatic injury and fibrosis triggered by cholestasis-related inflammation.

METHODS

Animals were randomly divided into three groups: sham-operated group, BDL group, and BDL+ AICAR group. Cholestatic liver injury was induced by common BDL. Two weeks later, rats in BDL+AICAR group started receiving AICAR treatment. Hepatic pathology was examined by haematoxylin and eosin (H&E) and sirius red staining and hydroxyproline assay was performed in evaluating the severity of hepatic cirrhosis. Real-time PCR and Western blot were performed for RNA gene expression of RNA and protein levels, respectively.

RESULTS

The BDL group showed liver injury as evidenced by histological changes and elevation in serum biochemicals, ductular reaction, fibrosis, and inflammation. The mRNA expression of canonical NF-κB inflammatory cytokines such as TNF-α, IL-1β, TGF-β, and the protein of noncanonical NF-κB, P100, and P52 was upregulated in the livers of BDL rats. The BDL rats with the administration of AICAR could induce AMPK activation inhibiting the noncanonical NF-κB pathway to attenuate liver injury and fibrosis in BDL rats.

CONCLUSION

The BDL model of hepatic cholestatic injury resulting in activation of Kupffer cells and recruitment of immune cells might initiate an inflammatory response through activation of the NF-κB pathway. The AMPK activator AICAR significantly alleviated BDL-induced inflammation in rats by mainly inhibiting the noncanonical NF-κB pathway and thus protecting against hepatic injury and fibrosis triggered by BDL.

Carnosic Acid Modulates Increased Hepatic Lipogenesis and Adipocytes Differentiation in Ovariectomized Mice Fed Normal or High-Fat Diets

As postmenopausal women experience a rapid increase in cardiovascular disease (CVD) risk with an increase in abdominal fat, dietary interventions to reduce CVD risk have been emphasized. This study was aimed at investigating the effect of a high-fat diet (HFD) in combination with an ovariectomy on liver and adipose tissue fat metabolism. The efficacy of carnosic acid (CA) supplementation in the suppression of HFD- and ovariectomy-induced obesity was also evaluated. Ovariectomized (OVX) or sham-operated mice at eight weeks of age were fed with a normal diet (ND), HFD, ND and 0.02% CA, or HFD and 0.02% CA for 12 weeks. All of the animals were sacrificed at the age of 20 weeks. The blood and tissue markers of the lipogenesis and adipocyte differentiation were measured. As expected, ovariectomy decreased the uterus weight and serum 17β-estradiol concentration. The HFD and ovariectomy significantly contributed to increases in the body weight and total fat mass, which were effectively inhibited by CA supplementation. The circulating concentrations of insulin, leptin, and TG (triglyceride) were significantly higher in the HFD group, and the concentrations were two to five times higher in the OVX and HFD group compared with those of the ND group. The CA supplementation significantly lowered the insulin, leptin, and TG concentrations in the OVX and HFD mice. The hepatic protein expressions of pAMPK and pACC were up-regulated by CA supplementation in OVX mice fed either ND or HFD. The expressions of hepatic SREBP1c and FAS mRNA were the highest in the OVX and HFD group, which were suppressed by CA supplementation. The adipose tissue PPARγ, aP2, and lipoprotein lipase (LPL) mRNA expressions were up-regulated by a HFD or ovariectomy, while they were significantly reduced in the mice fed a CA supplemented diet. The TNF-α and IL-6 mRNA levels in the adipose tissue were decreased by providing CA in the OVX groups. These results suggest that HFD and ovariectomy independently contribute to body fat accumulation, and CA effectively alleviated the ovariectomy-induced increases in lipogenesis and adipocyte differentiation. Further human trials are required in order to evaluate the efficacy of rosemary-derive CA as natural anti-adipogenic compounds, especially in postmenopausal women.

Chitosan Oligosaccharides Improve Glucolipid Metabolism Disorder in Liver by Suppression of Obesity-Related Inflammation and Restoration of Peroxisome Proliferator-Activated Receptor Gamma (PPARγ)

Chitosan oligosaccharides (COS) display various biological activities. In this study, we aimed to explore the preventive effects of COS on glucolipid metabolism disorder using palmitic acid (PA)-induced HepG2 cells and high-fat diet (HFD)-fed C57BL/6J mice as experimental models in vitro and in vivo, respectively. The results showed that COS pretreatment for 12 h significantly ameliorated lipid accumulation in HepG2 cells exposed to PA for 24 h, accompanied by a reversing of the upregulated mRNA expression of proinflammatory cytokines (IL-6, MCP-1, TNF-α) and glucolipid metabolism-related regulators (SCD-1, ACC1, PCK1-α). In addition, COS treatment alleviated glucolipid metabolism disorder in mice fed with HFD for five months, including reduction in body weight and fasting glucose, restoration of intraperitoneal glucose tolerance, and suppression of overexpression of proinflammatory cytokines and glucolipid metabolism-related regulators. Furthermore, our study found that COS pretreatment significantly reversed the downregulation of PPARγ at transcriptional and translational levels in both PA-induced HepG2 cells and liver tissues of HFD-fed mice. In summary, the study suggests that COS can improve glucolipid metabolism disorder by suppressing inflammation and upregulating PPARγ expression. This indicates a novel application of COS in preventing and treating glucolipid metabolism-related diseases.

Impact of curcumin on sirtuins: A review

Curcumin is a bioactive phytochemical that modulates several physiological and cellular processes leading to therapeutic effects against different diseases. Sirtuins are highly conserved nicotine adenine dinucleotide-dependent proteins that regulate the activity of target enzymes and transcription factors by deacetylation. Curcumin possesses both antioxidant and anti-inflammatory properties and has been shown to increase sirtuin-1 (SIRT1) by activating small molecules. Upregulation of SIRT1 by curcumin has been reported to confer protective effects against a range of neurological disorders including glutamate excitotoxicity, β-amyloid-induced cell death in cortical neurons, cerebral ischemic damage, and stroke. Activation of AMPK and SIRT1 by curcumin has also been noted to mediate the protective effects of curcumin against ischemia/reperfusion injury, cardiac fibrosis, diabetes, and lipid metabolism abnormalities. These protective effects of SIRT1 activation are partly mediated by the deacetylation of p53 and reduction of apoptosis. In this review, we summarize the role of SIRT1 in mediating the pharmacological effects of curcumin in several diseases.

The Pharmacological Targets and Clinical Evidence of Natural Products With Anti-hepatic Inflammatory Properties

Inflammation contributes heavily to the pathogenesis of liver fibrosis, cirrhosis, and even hepatocellular carcinoma. Inflammation is probably a promising target for treatment of liver diseases. The natural products are considered as the potential source of new drug discovery and their pharmacological effects on hepatic inflammation have been widely reported. In this review, the natural products with anti-hepatic inflammatory properties are summarized based on their pharmacological effects and mechanisms, which are related to the suppression on the inflammation mediators including cytokines and chemokines, pattern recognition receptors, the activated transcriptional factors, and the potential regulatory factors. The clinical evidence is also summarized.

Protein Expression Profile of Twenty-Week-Old Diabetic db/db and Non-Diabetic Mice Livers: A Proteomic and Bioinformatic Analysis

Type 2 diabetes mellitus is characterized by insulin resistance in the liver. Insulin is not only involved in carbohydrate metabolism, it also regulates protein synthesis. This work describes the expression of proteins in the liver of a diabetic mouse and identifies the metabolic pathways involved. Twenty-week-old diabetic db/db mice were hepatectomized, after which proteins were separated by 2D-Polyacrylamide Gel Electrophoresis (2D-PAGE). Spots varying in intensity were analyzed using mass spectrometry, and biological function was assigned by the Database for Annotation, Visualization and Integrated Discovery (DAVID) software. A differential expression of 26 proteins was identified; among these were arginase-1, pyruvate carboxylase, peroxiredoxin-1, regucalcin, and sorbitol dehydrogenase. Bioinformatics analysis indicated that many of these proteins are mitochondrial and participate in metabolic pathways, such as the citrate cycle, the fructose and mannose metabolism, and glycolysis or gluconeogenesis. In addition, these proteins are related to oxidation⁻reduction reactions and molecular function of vitamin binding and amino acid metabolism. In conclusion, the proteomic profile of the liver of diabetic mouse db/db exhibited mainly alterations in the metabolism of carbohydrates and nitrogen. These differences illustrate the heterogeneity of diabetes in its different stages and under different conditions and highlights the need to improve treatments for this disease.

Micheliolide alleviates hepatic steatosis in db/db mice by inhibiting inflammation and promoting autophagy via PPAR-γ-mediated NF-кB and AMPK/mTOR signaling

The anti-inflammatory, immunomodulatory, and anticancer effects of micheliolide (MCL) isolated from Michelia champaca were previously reported, but its role and underlying mechanisms in relieving liver steatosis remain unclear. Herein, we investigated the effects of MCL on hepatic steatosis using a db/db mouse model and lipid mixture (LM)-induced AML12 and LO2 cells. The body and liver weights, food consumption, lipid content and liver aminotransferase levels in serum, the lipid content and inflammatory cytokine levels in liver tissue, and the extent of hepatic steatosis in db/db mice were increased compared with those in db/m mice, and these increases were reversed by MCL treatment. Similarly, MCL also attenuated the inflammatory responses and lipid accumulation in LM-treated AML12 and L02 cells by upregulating PPAR-γ and decreasing p-IкBα and p-NF-κB/p65, thereby inhibiting the NF-κB pathway and reducing lipotoxicity. Furthermore, MCL administration increased LC3B, Atg7 and Beclin-1 expression and the LC3B-II/I ratio in db/db mouse livers and LM-treated AML12 and L02 cells, and these MCL-induced increases were mediated by the activation of PPAR-γ and p-AMPK and inhibition of p-mTOR and induce autophagy. These effects were blocked by PPAR-γ and AMPK inhibitors. Our findings suggest that MCL ameliorates liver steatosis by upregulating PPAR-γ expression, thereby inhibiting NF-κB-mediated inflammation and activating AMPK/mTOR-dependent autophagy.

The Potential and Action Mechanism of Polyphenols in the Treatment of Liver Diseases

Liver disease, involving a wide range of liver pathologies from fatty liver, hepatitis, and fibrosis to cirrhosis and hepatocellular carcinoma, is a serious health problem worldwide. In recent years, many natural foods and herbs with abundant phytochemicals have been proposed as health supplementation for patients with hepatic disorders. As an important category of phytochemicals, natural polyphenols have attracted increasing attention as potential agents for the prevention and treatment of liver diseases. The striking capacities in remitting oxidative stress, lipid metabolism, insulin resistance, and inflammation put polyphenols in the spotlight for the therapies of liver diseases. It has been reported that many polyphenols from a wide range of foods and herbs exert therapeutic effects on liver injuries via complicated mechanisms. Therefore, it is necessary to have a systematical review to sort out current researches to help better understand the potentials of polyphenols in liver diseases. In this review, we aim to summarize and update the existing evidence of natural polyphenols in the treatment of various liver diseases by in vitro, in vivo, and clinical studies, while special attention is paid to the action mechanisms.

Natural products, an important resource for discovery of multitarget drugs and functional food for regulation of hepatic glucose metabolism

Imbalanced hepatic glucose homeostasis is one of the critical pathologic events in the development of metabolic syndromes (MSs). Therefore, regulation of imbalanced hepatic glucose homeostasis is important in drug development for MS treatment. In this review, we discuss the major targets that regulate hepatic glucose homeostasis in human physiologic and pathophysiologic processes, involving hepatic glucose uptake, glycolysis and glycogen synthesis, and summarize their changes in MSs. Recent literature suggests the necessity of multitarget drugs in the management of MS disorder for regulation of imbalanced glucose homeostasis in both experimental models and MS patients. Here, we highlight the potential bioactive compounds from natural products with medicinal or health care values, and focus on polypharmacologic and multitarget natural products with effects on various signaling pathways in hepatic glucose metabolism. This review shows the advantage and feasibility of discovering multicompound-multitarget drugs from natural products, and providing a new perspective of ways on drug and functional food development for MSs.

Molecular mechanisms of the anti-obesity effect of bioactive ingredients in common spices: a review

The mechanisms of the anti-obesity effects of bioactive compounds in common spices in adipocytes, animal models and human participants have been reviewed.

Curcumin attenuates oxidative stress in liver in Type 1 diabetic rats

We investigated the effect of curcumin on liver anti-oxidative stress in the type 1 diabetic rat model induced by streptozotocin (STZ). Experimental diabetic rats were induced by STZ intraperitoneally. All rats were fed for 21 days including three groups of control (NC), diabetic model (DC) and curcumin-treated (Cur, 1.5 g/kg by gavage). The results showed that curcumin-treatment significantly decreased the blood glucose and plasma malondialdehyde levels, but significantly increased the plasma superoxide dismutase, glutathione peroxidase and reduced glutathione levels. Curcumin treatment decreased the activity of aldose reductase, but increased the plasma glucose-6-phosphate dehydrogenase, glucose synthetase and glucose-polymerizing activities. Curcumin treatment significantly decreased the protein of protein kinase C (PKC) and poly ADP ribose polymerase (PARP) expression in the Cur group compared with the DC group. Moreover, the sorbitol dehydrogenase activity was significantly decreased and deterred glucose enters into the polyol pathway leading to an increased NADPH content in the Cur group compared with the DC group. Our data provides evidence that oxidative stress in diabetic rats may be attenuated by curcumin by inhibiting polyol pathway associated with down-regulated expression of PKC and PARP, as evidenced by both an increase the antioxidant enzymes levels and glycogen biosynthesis enzymes activities.

Protective effects of curcumin against aflatoxicosis: A comprehensive review

Aflatoxicosis is a deleterious medical condition that results from aflatoxins (AFs) or ochratoxins (OTs). Contamination with these toxins exerts detrimental effects on the liver, kidneys, reproductive organs, and also on immunological and cardiovascular systems. Aflatoxicosis is closely associated with overproduction of reactive oxygen species (ROS) as key contributors to oxidative and nitrosative stress responses, and subsequent damages to lipids, proteins, RNA, and DNA. The main target organ for AF toxicity is the liver, where DNA adducts, degranulation of endoplasmic reticulum, increased hepatic lipid peroxide, GSH depletion, mitochondrial dysfunction, and reduction of enzymatic and non-enzymatic antioxidants are manifestations of aflatoxicosis. Curcuma longa L. (turmeric) is a medicinal plant widely utilized all over the world for culinary and phytomedical purposes. Considering the antioxidant characteristic of curcumin, the main active component of turmeric, this review is intended to critically summarize the available evidence supporting possible effectiveness of curcumin against aflatoxicosis. Curcumin can serve as a promising candidate for attenuation of the adverse consequences of aflatoxicosis, acting mainly through intrinsic antioxidant effects aroused from its structure, modulation of the immune system as reflected by interleukin-1β and transforming growth factor-β, and interfering with AF's biotransformation by cytochrome P450 isoenzymes CYP1A, CYP3A, CYP2A, CYP2B, and CYP2C.

Curcumin alleviates liver oxidative stress in type 1 diabetic rats

The aim of the present study was to determine the effects of curcumin on antioxidants using a rat model of type 1 diabetes. Seven-week-old male Sprague-Dawley rats were injected with Streptozotocin (STZ) intraperitoneally to induce this model, and then treated with 1.0% curcumin (weight ratio) mixed in their diet for 21 days. The present study included three groups: Control group (NC), diabetic rat model group (DC) and a curcumin treated group (Diab-Cur). The results demonstrated that curcumin treatment markedly decreased the blood glucose levels, plasma malondialdehyde concentration and plasma activity of glutathione peroxidase (GSH-Px) and catalase (CAT); however, it increased the plasma superoxide dismutase (SOD) and insulin levels. Curcumin treatment increased the expression of the CAT, GSH-Px, HO-1 and norvegicus NAD(P)H quinone dehydrogenase 1, and decreased the SOD1 expression, which, led to a diminished oxidative stress status. In addition, curcumin treatment significantly increased the protein expression of Keap1 in the Diab-Cur group when compared with the DC group, decreased cytosolic concentrations of Nrf2 while increasing nuclear accumulation of Nrf2. The results provide evidence that oxidative stress in the STZ-induced diabetic rat model may be attenuated by curcumin via the activation of the Keap1-Nrf2-ARE signaling pathway, as evidenced by a decrease in the blood glucose concentration and an increase in the transcription of several antioxidant genes.

Antidiabetic Effect of Tibetan Medicine Tang-Kang-Fu-San in db/db Mice via Activation of PI3K/Akt and AMPK Pathways

This study was to investigate the anti-diabetic effects and molecular mechanisms of Tang-Kang-Fu-San (TKFS), a traditional Tibetan medicine, in treating type 2 diabetes mellitus of spontaneous diabetic db/db mice. Firstly HPLC fingerprint analysis was performed to gain the features of the chemical compositions of TKFS. Next different doses of TKFS (0.5 g/kg, 1.0 g/kg, and 2.0 g/kg) were administrated via oral gavage to db/db mice and their controls for 4 weeks. TKFS significantly lowered hyperglycemia and ameliorated insulin resistance (IR) in db/db mice, indicated by results from multiple tests, including fasting blood glucose test, intraperitoneal insulin and glucose tolerance tests, fasting serum insulin levels and homeostasis model assessment of IR analysis as well as histology of pancreas islets. TKFS also decreased concentrations of serum triglyceride, total and low-density lipoprotein cholesterol, even though it did not change the mouse body weights. Results from western blot and immunohistochemistry analysis indicated that TKFS reversed the down-regulation of p-Akt and p-AMPK, and increased the translocation of Glucose transporter type 4 in skeletal muscles of db/db mice. In all, TKFS had promising benefits in maintaining the glucose homeostasis and reducing IR. The underlying molecular mechanisms are related to promote Akt and AMPK activation and Glucose transporter type 4 translocation in skeletal muscles. Our work showed that multicomponent Tibetan medicine TKFS acted synergistically on multiple molecular targets and signaling pathways to treat type 2 diabetes mellitus.

Curcumin prevents reperfusion injury following ischemic stroke in rats via inhibition of NF‑κB, ICAM-1, MMP-9 and caspase-3 expression

Reperfusion is the only approved therapy for acute ischemic stroke; however, it can cause excessive inflammation responses and aggravate brain damage. Therefore, supplementary treatment against inflammation caused by reperfusion is required. In a previous study from our group, curcumin was demonstrated to decrease infarction volume, brain edema and blood-brain barrier (BBB) disruption against cerebral ischemia/reperfusion (I/R) injury. However, the underlying mechanisms remain unclear. The present study was conducted to understand whether curcumin protects against cerebral I/R injury through anti-inflammatory and antiapoptotic properties. Ischemia for 1 h was induced in vivo in Wistar rats by middle cerebral artery occlusion (MCAO), followed by reperfusion for 24 h, and curcumin was injected intraperitoneally at 30 min prior to reperfusion. Immunohistochemistry was performed to analyze the expression levels of nuclear factor (NF)-κB, intercellular adhesion molecule (ICAM)-1, matrix metalloproteinase (MMP)-9 and caspase-3. The findings revealed that inflammation (NF-κB, ICAM-1 and MMP-9) and apoptosis (caspase-3)-related markers were significantly downregulated in the curcumin-treated MCAO group compared with the vehicle-treated MCAO group. Furthermore, brain infarction size, brain edema and neurological dysfunction were attenuated in the curcumin-treated MCAO group compared with the vehicle-treated MCAO group. Taken together, the present results provided evidence that the protective effect of curcumin against cerebral I/R injury might be mediated by anti-inflammatory and anti-apoptotic properties. Therefore, curcumin may be a promising supplementary agent against cerebral I/R injury in the future.

Mitochondrial content, oxidative, and nitrosative stress in human full-term placentas with gestational diabetes mellitus

BACKGROUND

The purpose of this study was to determine the mitochondrial content, and the oxidative and nitrosative stress of the placenta in women with gestational diabetes mellitus (GDM).

METHODS

Full-term placentas from GDM and healthy pregnancies were collected following informed consent. The lipid peroxidation (TBARS) and oxidized protein (carbonyls) levels were determined by spectrophotometry, and 3-nitrotyrosine (3-NT), subunit IV of cytochrome oxidase (COX4), adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) and actin were determined by western blot, whereas ATPase activity was performed by determining the adenosine triphosphate (ATP) consumption using a High-performance liquid chromatography (HPLC) system.

RESULTS

TBARS and carbonyls levels were lower in the placentas of women with GDM compared with the normal placentas (p < 0.001 and p < 0.05, respectively). Also, 3-NT/actin and AMPK/actin ratios were higher in GDM placentas than in the normal placentas (p = 0.03 and p = 0.012, respectively). Whereas COX4/actin ratio and ATPase activity were similar between GDM placentas and those controls.

CONCLUSIONS

These data suggest that placentas with GDM are more protected against oxidative damage, but are more susceptible to nitrosative damage as compared to normal placentas. Moreover, the increased expression levels of AMPK in GDM placentas suggest that AMPK might have a role in maintaining the mitochondrial biogenesis at normal levels.

TRIAL REGISTRATION

HGRL28072011 . Registered 28 July 2011.

Review. The role of peroxisome proliferator-activated receptor in the treatment of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) has been defined as a spectrum of histological abnormalities and is characterized by significant and excessive accumulation of triglycerides in the hepatocytes in patients without alcohol consumption or other diseases. Current studies are targeting new molecular mechanisms that underlie NAFLD and associated metabolic disorders. Many therapeutic targets have been found and used in clinical studies. Peroxisome proliferator-activated receptors (PPARs) are among the potential targets and have been demonstrated to exert a pivotal role in modulation of NAFLD. Many drugs developed so far are targeted at PPARs. Thus, the aim of this paper is to summarize the roles of PPARs in the treatment of NAFLD.

Molecular factors involved in the hypolipidemic- and insulin-sensitizing effects of a ginger (Zingiber officinale Roscoe) extract in rats fed a high-fat diet

Hypolipidemic and hypoglycemic properties of ginger in animal models have been reported. However, information related to the mechanisms and factors involved in the metabolic effects of ginger at a hepatic level are limited. The aim of the present study was to investigate molecular factors involved in the hypoglycemic and hypolipidemic effects of a hydroethanolic ginger extract (GE) in the liver of rats fed a high-fat diet (HFD). The study was conducted in male Wistar rats divided into the following 3 groups: (i) Rats fed a standard diet (3.5% fat), the control group; (ii) rats fed an HFD (33.5% fat); and (iii) rats fed an HFD treated with GE (250 mg·kg-1·day-1) for 5 weeks (HFD+GE). Plasma levels of glucose, insulin, lipid profile, leptin, and adiponectin were measured. Liver expression of glycerol phosphate acyltransferase (GPAT), cholesterol 7 alpha-hydroxylase, peroxisome proliferator-activated receptors (PPAR), PPARα and PPARγ, glucose transporter 2 (GLUT-2), liver X receptor, sterol regulatory element-binding protein (SREBP1c), connective tissue growth factor (CTGF), and collagen I was measured. Data were analyzed using a 1-way ANOVA, followed by a Newman-Keuls test if differences were noted. The study showed that GE improved lipid profile and attenuated the increase of plasma levels of glucose, insulin, and leptin in HFD rats. This effect was associated with a higher liver expression of PPARα, PPARγ, and GLUT-2 and an enhancement of plasma adiponectin levels. Furthermore, GE reduced liver expression of GPAT, SREBP1c, CTGF, and collagen I. The results suggest that GE might be considered as an alternative therapeutic strategy in the management of overweight and hepatic and metabolic-related alterations.

Irbesartan ameliorates hyperlipidemia and liver steatosis in type 2 diabetic db/db mice via stimulating PPAR-γ, AMPK/Akt/mTOR signaling and autophagy

Irbesartan (Irb), a unique subset of angiotensin II receptor blockers (ARBs) with PPAR-γ activation function, has been reported to play a role in renal dysfunction, glucose metabolism, and abnormal lipid profile in diabetic animal models and humans. However, the underlying mechanisms that improve hyperlipidemia and liver steatosis are unclear. This study investigated the effects of Irb on lipid metabolism and hepatic steatosis using the spontaneous type 2 diabetic db/db mouse model. The results demonstrated body and liver weight, food consumption, lipid content in serum and liver tissue, and liver dysfunction as well as hepatic steatosis were increased in db/db mice compared with db/m mice, whereas the increases were reversed by Irb treatment. Moreover, Irb administration resulted in an increase in LC3BII as well as the LC3BII/I ratio through activating PPAR-γ and p-AMPK and inhibiting p-Akt and p-mTOR, thereby inducing autophagy in the db/db mouse liver. Therefore, our findings suggest that Irb can ameliorate hyperlipidemia and liver steatosis by upregulating the expression of PPAR-γ, activating the AMPK/Akt/mTOR signaling pathway and inducing liver autophagy.

Curcumin and long-chain Omega-3 polyunsaturated fatty acids for Prevention of type 2 Diabetes (COP-D): study protocol for a randomised controlled trial

Background

Lifestyle interventions, including increase in physical activity and dietary counselling, have shown the ability to prevent type 2 diabetes (T2D) in high-risk state individuals, but the prevalence is still skyrocketing in Australia, in line with global prevalence. Currently, no medicines are approved by the Therapeutic Goods Administration in Australia for the management of prediabetes. Therefore, there is a need of developing a safer, biologically efficacious and cost-effective alternative for delaying the transition of individual health state from prediabetes into T2D. In the current trial we propose to evaluate the effects of curcumin and/or long-chain omega-3 polyunsaturated fatty acids on improving glycosylated haemoglobin as a primary outcome, along with secondary outcomes of glycaemic indices, lipid profile and inflammatory parameters.

Methods/design

Eighty individuals diagnosed with prediabetes, aged between 30 and 70 years, will be randomly assigned to double placebo, curcumin alone, fish oil alone or double active groups according to a computer-generated randomisation sequence for 12 weeks. At baseline and post-intervention visits participants will be asked to provide blood samples and undergo body composition measurements. A blood sample is used for estimating glycaemic profiles, lipid profiles and inflammatory parameters (C-reactive protein, whole blood cell count, adiponectin, leptin, interleukin-6). The interim visit includes review on compliance with supplements based on capsule log and capsule count, adverse events and anthropometric measurements. In addition to these procedures, participants provide self-reported questionnaires on dietary intake (using a 3-day food record), a physical activity questionnaire and medical history.

Discussion

This trial aims to determine whether curcumin and/or long-chain omega-3 polyunsaturated fatty acids affect surrogate markers of glycaemic control which is relevant to delaying T2D. To date 38 participants completed the trial. No changes have been made to the clinical protocol post recruitment. If successful, this trial will provide considerable evidence for performing a larger trial to investigate whether this combination can be administered for preventing or delaying the onset of T2D in high-risk individuals.

Trial registration

ACTRN12615000559516, registered on 29 May 2015).

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-016-1702-9) contains supplementary material, which is available to authorized users.

Role of nutraceutical SIRT1 modulators in AMPK and mTOR pathway: Evidence of a synergistic effect

OBJECTIVE

The aim of this study was to evaluate the effect of different natural substances on SIRT1 expression and on AMPK and mTOR phosphorylation. Moreover, we investigated the presence of a synergistic effect between the substances.

METHODS

Human cervical carcinoma cells were seeded in 12-well plates, then incubated with the nine tested substances (resveratrol, quercetin, berberine, catechin, tyrosol, ferulic acid, niclosamide, curcumin, and malvidin) at different concentrations and left in incubation for 3, 6, and 24 h. The targeting proteins' expression and phosphorylation were evaluated by immunoblotting, and cytotoxicity tests were performed by CellTiter-Blue Cell Viability Assay.

RESULTS

No statistically significant decrease (P > 0.05) in the number of viable cells was found. The expression of SIRT1 was significantly increased in all experimental groups compared with the control group (P < 0.001). Instead, the simultaneous administration involved a significant and synergistic increase in the expression of SIRT1 for some but not all of the tested compounds. Finally, the individual administration of berberine, quercetin, ferulic acid, and tyrosol resulted in a statistically significant increase in AMPK activation and mTOR inhibition, whereas their associated administration did not reveal a synergistic effect.

CONCLUSIONS

Our results provide evidence that all compounds have the potential to stimulate SIRT1 and sustain the stimulating action of resveratrol on SIRT1, already widely reported in the literature. In this regard, we confirm the interaction of these substances also with the pathway of AMPK and mTOR, in support of the studies that highlight the importance of SIRT1/AMPK and mTOR pathway in many diseases.

Controls of Nuclear Factor-Kappa B Signaling Activity by 5'-AMP-Activated Protein Kinase Activation With Examples in Human Bladder Cancer Cells

Generally, both lipopolysaccharide (LPS)- and hypoxia-induced nuclear factor kappa B (NF-κB) effects are alleviated through differential posttranslational modification of NF-κB phosphorylation after pretreatment with 5´-AMP-activated protein kinase (AMPK) activators such as 5´-aminoimidazole-4-carboxamide ribonucleotide (AICAR) or the hypoglycemic agent metformin. We found that AICAR or metformin acts as a regulator of LPS/NF-κB-or hypoxia/NF-κB-mediated cyclooxygenase induction by an AMPK-dependent mechanism with interactions between p65-NF-κB phosphorylation and acetylation, including in a human bladder cancer cell line (T24). In summary, we highlighted the regulatory interactions of AMPK activity on NF-κB induction, particularly in posttranslational phosphorylation and acetylation of NF-κB under inflammatory conditions or hypoxia environment.

Dietary Phytochemicals: Natural Swords Combating Inflammation and Oxidation-Mediated Degenerative Diseases

Cumulatively, degenerative disease is one of the most fatal groups of diseases, and it contributes to the mortality and poor quality of life in the world while increasing the economic burden of the sufferers. Oxidative stress and inflammation are the major pathogenic causes of degenerative diseases such as rheumatoid arthritis (RA), diabetes mellitus (DM), and cardiovascular disease (CVD). Although a number of synthetic medications are used to treat these diseases, none of the current regimens are completely safe. Phytochemicals (polyphenols, carotenoids, anthocyanins, alkaloids, glycosides, saponins, and terpenes) from natural products such as dietary fruits, vegetables, and spices are potential sources of alternative medications to attenuate the oxidative stress and inflammation associated with degenerative diseases. Based on in vitro, in vivo, and clinical trials, some of these active compounds have shown good promise for development into novel agents for treating RA, DM, and CVD by targeting oxidative stress and inflammation. In this review, phytochemicals from natural products with the potential of ameliorating degenerative disease involving the bone, metabolism, and the heart are described.

Curcumol Suppresses Breast Cancer Cell Metastasis by Inhibiting MMP-9 Via JNK1/2 and Akt-Dependent NF-κB Signaling Pathways

Curcumolhas been reported to possess antitumor activity. However, its effect and mechanisms against tumor metastasis are still unclear. This study is to investigate the inhibitory effect of curcumol on breast cancer cell metastasis and elucidate the underlying molecular mechanisms. Our results showed that noncytotoxicity was caused by curcumol within 10 to 40 µg/mL in MDA-MB-231 and 4T1 cells for 24 hours, whereas sustained treatment with curcumol for 14 days significantly suppressed the clonogenic activity of cells. Importantly, curcumol at noncytotoxic concentrations suppressed the migration ability of both MDA-MB-231 and 4T1 cells. Moreover, curcumol suppressed the migration and invasion of MDA-MB-231 cells in the Boyden chamber migration and invasion assay and inhibited the adhesion of MDA-MB-231 cells onto the matrigel. Further investigations revealed that curcumol decreased the enzyme activity and protein expression of matrix metalloproteinase (MMP-9) in MDA-MB-231 cells. Moreover, curcumol inhibited the activation of c-Jun N-terminal kinase (JNK) 1/2 and Akt (Ser473). Meanwhile, it also inhibited the nuclear translocation and transcriptional activity of nuclear factor κB (NF-κB). Furthermore, JNK inhibitor SP600125 and Akt (Ser473) inhibitor LY294002 enhanced the inhibition of curcumol on NF-κB p65 nuclear translocation. Finally, supplementation with SP600125, LY294002, or NF-κB inhibitor Ammonium pyrrolidinedithiocarbamate (PDTC) significantly enhanced the inhibitory effect of curcumol on MMP-9 expression and cell migration, invasion, and adhesion in MDA-MB-231 cells. Our findings provide evidence for the suppression of breast cancer cell metastasis by curcumol and suggest that the inhibition of MMP-9 via JNK1/2 and Akt (Ser473)-dependent NF-κB signaling pathways may be the underlying mechanisms.

Anti-diabetic activities of catalpol in db/db mice

The objective was to investigate the hypoglycemic action of catalpol in spontaneous diabetes db/db mice. 40 db/db mice were randomly divided into fi ve groups: model control gourp; db/db plus catalpol 40, 80, 120 mg/kg body wt. groups and db/db plus metformin 250 mg/kg group. Age-matched db/m mice were selected as normal control group. The mice were administered with corresponding drugs or solvent by gavage for 4 weeks. The oral glucose tolerance test was carried out at the end of 3(rd) week. After 4 weeks of treatment, the concentrations of fasting blood glucose (FBG), glycated serum protein (GSP), insulin (INS), triglyceride (TG), total cholesterol (TC) and adiponection (APN) in serum were detected. The protein expressions of phosphorylation-AMPKα1/2 in liver, phosphorylation-AMPKα1/2 and glucose transporter-4 (GLUT-4) in skeletal muscle and adipose tissues were detected by western blot. Real time RT-PCR was used to detect the mRNA expressions of acetyl-CoA carboxylase (ACC) and Hydroxymethyl glutaric acid acyl CoA reductase (HMGCR) in liver. Our results showed that catalpol could significantly improve the insulin resistance, decrease the serum concentrations of INS, GSP, TG, and TC. The concentrations of APN in serum, the protein expression of phosphorylation-AMPKα1/2 in liver, phosphorylation-AMPKα1/2 and GLUT-4 in peripheral tissue were increased. Catalpol could also down regulate the mRNA expressions of ACC and HMGCR in liver. In conclusion, catalpol ameliorates diabetes in db/db mice. It has benefi t eff ects against lipid/glucose metabolism disorder and insulin resistance. The mechanism may be related to up-regulating the expression of phosphorylation-AMPKα1/2.

Molecular mechanisms underlying chemopreventive potential of curcumin: Current challenges and future perspectives

In recent years, natural compounds have received considerable attention in preventing and curing most dreadful diseases including cancer. The reason behind the use of natural compounds in chemoprevention is associated with fewer numbers of side effects than conventional chemotherapeutics. Curcumin (diferuloylmethane, PubMed CID: 969516), a naturally occurring polyphenol, is derived from turmeric, which is used as a common Indian spice. It governs numerous intracellular targets, including proteins involved in antioxidant response, immune response, apoptosis, cell cycle regulation and tumor progression. A huge mass of available studies strongly supports the use of Curcumin as a chemopreventive drug. However, the main challenge encountered is the low bioavailability of Curcumin. This extensive review covers various therapeutic interactions of Curcumin with its recognized cellular targets involved in cancer treatment, strategies to overcome the bioavailability issue and adverse effects associated with Curcumin consumption.

Curcumin Suppresses Proliferation and Migration of MDA-MB-231 Breast Cancer Cells through Autophagy-Dependent Akt Degradation

Previous studies have evidenced that the anticancer potential of curcumin (diferuloylmethane), a main yellow bioactive compound from plant turmeric was mediated by interfering with PI3K/Akt signaling. However, the underlying molecular mechanism is still poorly understood. This study experimentally revealed that curcumin treatment reduced Akt protein expression in a dose- and time-dependent manner in MDA-MB-231 breast cancer cells, along with an activation of autophagy and suppression of ubiquitin-proteasome system (UPS) function. The curcumin-reduced Akt expression, cell proliferation, and migration were prevented by genetic and pharmacological inhibition of autophagy but not by UPS inhibition. Additionally, inactivation of AMPK by its specific inhibitor compound C or by target shRNA-mediated silencing attenuated curcumin-activated autophagy. Thus, these results indicate that curcumin-stimulated AMPK activity induces activation of the autophagy-lysosomal protein degradation pathway leading to Akt degradation and the subsequent suppression of proliferation and migration in breast cancer cell.

Regulation of AMP-activated protein kinase by natural and synthetic activators

The AMP-activated protein kinase (AMPK) is a sensor of cellular energy status that is almost universally expressed in eukaryotic cells. While it appears to have evolved in single-celled eukaryotes to regulate energy balance in a cell-autonomous manner, during the evolution of multicellular animals its role has become adapted so that it also regulates energy balance at the whole body level, by responding to hormones that act primarily on the hypothalamus. AMPK monitors energy balance at the cellular level by sensing the ratios of AMP/ATP and ADP/ATP, and recent structural analyses of the AMPK heterotrimer that have provided insight into the complex mechanisms for these effects will be discussed. Given the central importance of energy balance in diseases that are major causes of morbidity or death in humans, such as type 2 diabetes, cancer and inflammatory disorders, there has been a major drive to develop pharmacological activators of AMPK. Many such activators have been described, and the various mechanisms by which these activate AMPK will be discussed. A particularly large class of AMPK activators are natural products of plants derived from traditional herbal medicines. While the mechanism by which most of these activate AMPK has not yet been addressed, I will argue that many of them may be defensive compounds produced by plants to deter infection by pathogens or grazing by insects or herbivores, and that many of them will turn out to be inhibitors of mitochondrial function.

The effect of dietary curcumin and capsaicin on hepatic fetuin-A expression and fat accumulation in rats fed on a high-fat diet

Effects of curcumin (turmeric) and capsaicin (red pepper) on hepatic fat accumulation and fetuin-A expression in rats fed high-fat diet (HFD) is aimed to be investigated. Male Sprague-Dawley rats received HFD (60% of total calories from fat) and 0.15 g capsaicin/kg HFD and/or 1.5 g curcumin/kg HFD for 16 weeks. Hepatic AMPK, p-AMPK and fetuin-A expressions were determined by western blotting, liver lipid levels were measured with colorimetric methods and serum fetuin-A, insulin, leptin and adiponectin levels were detected using commercial ELISA kits. HFD increased hepatic lipid levels, fetuin-A expression and serum leptin, insülin and fetuin-A levels. Curcumin and capsaicin treatments significantly reduced hepatic fat accumulation and leptin levels; liver fetuin-A expression was decreased significantly by the curcumin treatment. Curcumin and capsaicin treatments attenuated hepatic fat accumulation and increased leptin levels related to inflammation. The suppression of hepatic fetuin-A expression is observed to be especially sensitive to curcumin.

Curcumin by down-regulating NF-kB and elevating Nrf2, reduces brain edema and neurological dysfunction after cerebral I/R

BACKGROUND

Oxidation, inflammation, and apoptosis are three critical factors for the pathogenic mechanism of cerebral ischemia/reperfusion (I/R) injury. Curcumin exhibits substantial biological properties via anti-oxidation, anti-inflammation and anti-apoptotic effects; however, the molecular mechanism underlying the effects of curcumin against cerebral I/R injury remains unclear.

OBJECTIVE

To investigate the effects of curcumin on cerebral I/R injury associated with water content, infarction volume, and the expression of nuclear factor-kappa-B (NF-κB) and nuclear factor-erythroid-related factor-2 (Nrf2).

METHODS

Middle cerebral artery occlusion (MCAO, 1-hour occlusion and 24-hour reperfusion) was performed in male Wistar rats (n=64) as a cerebral I/R injury model. In the MCAO+CUR group, the rats were administered curcumin (300mg/kg BW, i.p.) at 30min after occlusion. The same surgical procedures were performed in SHAM rats without MCAO occlusion. At 24h post-operation, the parameters, including neurological deficit scores, blood brain barrier (BBB) disruption, water content, and infarction volume, were determined. Brain tissue NF-κB and Nrf2 expression levels were assayed through immunohistochemistry.

RESULTS

Compared with the SHAM group, BBB disruption, neurological deficit, and increased brain water content and infarction volume were markedly demonstrated in the MCAO group. NF-κB expression was enhanced in the MCAO group. However, in the MCAO+CUR group, the upregulation of Nrf2, an anti-oxidation related protein, was consistent with a significant decline in the water content, infarction volume, and NF-κB expression.

CONCLUSION

The protective effects of curcumin against cerebral I/R injury reflect anti-oxidation, anti-inflammation and anti-apoptotic activities, resulting in the elevation of Nrf2 and down-regulation of NF-κB.

Recent Advances of Curcumin and its Analogues in Breast Cancer Prevention and Treatment

More than 230,000 diagnosed cases of invasive breast cancer in women was estimated in 2014 and an expected 40,000 deaths attributed to the aggressive carcinoma. An effective approach to diminish the morbidity and mortality of breast cancer is the development of chemopreventive and chemotherapeutic agents. Nutraceuticals have demonstrated their ability to proficiently halt carcinogenesis. The administration of natural compounds able to effectively serve as chemoprevention and chemotherapeutics without causing harm or adverse effects is imperative. Curcumin derived from the rhizome of Curcuma longa L., is a common spice of India, used for centuries because of its medicinal properties. The main component of curcumin possesses a wide range of biological activities; anti-proliferative, anti-inflammatory, and apoptotic characteristics modulated through the inactivation of pathways such as EGK and Akt/mTOR. In addition, curcumin alters the expression of cytokines, transcription factors, and enzymes involved in cell vitality. The in vivo application of curcumin in breast cancer is hindered by its limited bioavailabiity. The synthesis of curcumin analogues and delivery via nanoparticles has demonstrated enhanced bioavailability of curcumin in the malignancy. This review focuses on recent developments in the use of curcumin, curcumin analogues, and novel delivery systems as a preventive and therapeutic method for breast cancer.

The beneficial role of curcumin on inflammation, diabetes and neurodegenerative disease: A recent update

The concept of using phytochemicals has ushered in a new revolution in pharmaceuticals. Naturally occurring polyphenols (like curcumin, morin, resveratrol, etc.) have gained importance because of their minimal side effects, low cost and abundance. Curcumin (diferuloylmethane) is a component of turmeric isolated from the rhizome of Curcuma longa. Research for more than two decades has revealed the pleiotropic nature of the biological effects of this molecule. More than 7000 published articles have shed light on the various aspects of curcumin including its antioxidant, hypoglycemic, anti-inflammatory and anti-cancer activities. Apart from these well-known activities, this natural polyphenolic compound also exerts its beneficial effects by modulating different signalling molecules including transcription factors, chemokines, cytokines, tumour suppressor genes, adhesion molecules, microRNAs, etc. Oxidative stress and inflammation play a pivotal role in various diseases like diabetes, cancer, arthritis, Alzheimer's disease and cardiovascular diseases. Curcumin, therefore, could be a therapeutic option for the treatment of these diseases, provided limitations in its oral bioavailability can be overcome. The current review provides an updated overview of the metabolism and mechanism of action of curcumin in various organ pathophysiologies. The review also discusses the potential for multifunctional therapeutic application of curcumin and its recent progress in clinical biology.

The neuroprotective role of metformin in advanced glycation end product treated human neural stem cells is AMPK-dependent

Diabetic neuronal damage results from hyperglycemia followed by increased formation of advanced glycosylation end products (AGEs), which leads to neurodegeneration, although the molecular mechanisms are still not well understood. Metformin, one of the most widely used anti-diabetic drugs, exerts its effects in part by activation of AMP-activated protein kinase (AMPK). AMPK is a critical evolutionarily conserved enzyme expressed in the liver, skeletal muscle and brain, and promotes cellular energy homeostasis and biogenesis by regulating several metabolic processes. While the mechanisms of AMPK as a metabolic regulator are well established, the neuronal role for AMPK is still unknown. In the present study, human neural stem cells (hNSCs) exposed to AGEs had significantly reduced cell viability, which correlated with decreased AMPK and mitochondria associated gene/protein (PGC1α, NRF-1 and Tfam) expressions, as well as increased activation of caspase 3 and 9 activities. Metformin prevented AGEs induced cytochrome c release from mitochondria into cytosol in the hNSCs. Co-treatment with metformin significantly abrogated the AGE-mediated effects in hNSCs. Metformin also significantly rescued hNSCs from AGE-mediated mitochondrial deficiency (lower ATP, D-loop level, mitochondrial mass, maximal respiratory function, COX activity, and mitochondrial membrane potential). Furthermore, co-treatment of hNSCs with metformin significantly blocked AGE-mediated reductions in the expression levels of several neuroprotective genes (PPARγ, Bcl-2 and CREB). These findings extend our understanding of the molecular mechanisms of both AGE-induced neuronal toxicity, and AMPK-dependent neuroprotection by metformin. This study further suggests that AMPK may be a potential therapeutic target for treating diabetic neurodegeneration.

The effect of curcumin on liver fibrosis in the rat model of microsurgical cholestasis

We aimed to determine the effects of curcumin on liver fibrosis and to clarify the role of nuclear factor-κB (NF-κB) and inducible nitric oxide synthase (iNOS) in a model of microsurgical cholestasis in the early stage of extrahepatic biliary atresia.

Effect of curcumin on hepatic antioxidant enzymes activities and gene expressions in rats intoxicated with aflatoxin B1

Twenty-eight rats were examined in a 5-week experiment to investigate the effect of curcumin on gene expression and activities of hepatic antioxidant enzymes in rats intoxicated with aflatoxin B1 (AFB1 ). The rats were divided into four groups. Rats in 1-4 groups served as control, oral curcumin treated (15 mg/kg body weight), single i.p. dose of AFB1 (3 mg/kg body weight) and combination of single i.p. dose of AFB1 with oral curcumin treated, respectively. AFB1 Liver damage and oxidative stress were evident in untreated AFB1 -intoxicated rats as indicated by a significant elevation in hepatic transaminases, elevation in lipid peroxide biomarkers (thiobarbituric acid reactive substances; TBARS), reduction of reduced glutathione (GSH) concentration, reduction in the activities of antioxidant enzymes namely catalase (CAT), total superoxide dismutase (SOD), glutathione peroxidase (GPX) and glutathione-S-transferase (GST) and down-regulation of gene expression of these antioxidant enzymes compared to control. Liver sections of rats intoxicated with AFB1 showed a disrupted lobular architecture, scattered necrotic cells and biliary proliferation. Administration of curcumin with AFB1 resulted in amelioration of AFB1 -induced effects compared to untreated AFB1 -intoxicated rats via an up-regulation of antioxidant enzyme gene expression, activation of the expressed genes and increase in the availability of GSH.

Curcumin inhibits cell proliferation and induces apoptosis in cholangiocarcinoma

AIM: To investigate the effect of curcumin on proliferation and apoptosis of cholangiocarcinoma cells and whether curcumin shows a therapeutic effect on cholangicarcinoma in vivo.

METHODS: CCK-8 assay was employed to investigate the effect of curcumin on cell proliferation in cholangiocarcinoma cell lines QBC939, RBE and TFK-1. Flow cytometry was employed to assess the effect of curcumin on cell apoptosis in cholangiocarcinoma cell lines. A nude mouse model of orthotopic transplantation of cholangiocarcinoma was developed to investigate the effect of curcumin on weight gain and survival state of mice.

RESULTS: Curcumin inhibited the proliferation of QBC939, RBE and TFK-1 cells (P < 0.05) in a dose- and time-dependent manner. Curcumin significantly induced apoptosis of cholangiocinoma cells. When curcumin concentrations were 0, 0.1, 1, 5 and 10 μmol/L, the corresponding apoptosis rates were 8.41% ± 1.22%, 21.49% ± 2.58%, 48.53% ± 2.41%, 69.75% ± 1.46% and 87.59% ± 3.25%, respectively (P < 0.05). In vivo experimental results show that curcumin significantly prolonged the survival time of tumor-bearing mice (P < 0.05) and significantly improved their survival state (P < 0.05).

CONCLUSION: Curcumin inhibits cell proliferation and induces apoptosis in cholangiocarcinoma cell lines in vitro, and prolongs the survival time of cholangiocarcinoma bearing mice and improve their survival status in vivo.