New evidence for the therapeutic potential of curcumin to treat nonalcoholic fatty liver disease in humans

Comparison of the efficacy of curcumin and its nano formulation on dexamethasone-induced hepatic steatosis, dyslipidemia, and hyperglycemia in Wistar rats

Background and objective

Insulin resistance is a primary feature of type 2 diabetes. This study compared the effects of curcumin and its nanoformulation on insulin resistance, fasting blood sugar, liver function, GLUT4, lipid profile, and oxidative stress in the liver and pancreas in a diabetic model.

Methods

Thirty male Wistar rats were divided into five groups: a control group, a diabetic group, a diabetic group treated with metformin (40 mg/kg), a diabetic group treated with curcumin (100 mg/kg), and a diabetic group treated with curcumin NPs (100 mg/kg). Diabetes was induced by injecting dexamethasone daily for 14 days. Treatment with curcumin and curcumin NPs was administered by gavage for 14 days. Body weight and fasting blood sugar levels were measured on days 1, 14, and 28.

Results

The metformin, curcumin, and curcumin NPs groups showed significantly greater body weight gain than the untreated diabetic group (P < 0.001). In diabetic rats treated with curcumin and curcumin NPs, insulin resistance decreased by approximately 40 %, while fasting blood sugar levels dropped by 35-40 % (P < 0.001). The levels of liver enzymes (AST, ALT), cholesterol, triglycerides, LDL, and the oxidative stress marker MDA in liver and pancreatic tissues were reduced by 30-50 %. Additionally, beneficial markers such as albumin, HDL, antioxidants (GSH, SOD), and GLUT4 levels were increased by 25-45 % (P < 0.001). Nano-curcumin consistently showed greater improvements than curcumin, especially in reducing oxidative stress and supporting liver and pancreatic health.

Conclusion

This study demonstrates that curcumin NPs has a superior effect on reducing oxidative stress and improving metabolic parameters in diabetes compared to curcumin. by enhancing the bioavailability and stability of curcumin, the nanoformulation showed stronger therapeutic potential for managing high blood sugar, cholesterol issues, and liver health, positioning curcumin NPs as a promising alternative to conventional treatments for diabetes and its complications.

Far-infrared radiation alleviates steatohepatitis and fibrosis in metabolic dysfunction-associated fatty liver disease

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a disease that causes an abnormal accumulation of fat in the liver, triggering inflammation and fibrosis, the mechanism of which is not fully understood and for which there is a lack of specific drug therapy. Far-infrared radiation (FIR) has demonstrated evident therapeutic efficacy across various diseases, and novel nanomaterial graphene patches can emit it through electric heating. This study aimed to investigate the potential protective effects of FIR against MAFLD. Mice were fed with a MCD diet to mimic MAFLD progression, and histopathology analysis, biochemical analysis, RT-qPCR, and Western blotting analysis were performed to assess the effect of FIR on MAFLD in vivo. The effect of FIR treatment on MAFLD in vitro was investigated by biochemical analysis and gene expression profiling of hepatocytes. Mice subjected to the MCD diet and treated with FIR exhibited reduced hepatic lipid deposition, inflammation, fibrosis and liver damage. The therapeutic effect exerted by FIR in mice may be caused by the enhancement of AMPK phosphorylation and inhibition of the TGFβ1-SMAD2/3 pathway. Besides, FIR intervention alleviated MAFLD in hepatocytes in vitro and the results were verified by gene expression profiling. Our results revealed a promising potential of FIR as a novel therapeutic approach for MAFLD.

Berberine prevents NAFLD and HCC by modulating metabolic disorders

Non-alcoholic fatty liver disease (NAFLD) is a global metabolic disease with high prevalence in both adults and children. Importantly, NAFLD is becoming the main cause of hepatocellular carcinoma (HCC). Berberine (BBR), a naturally occurring plant component, has been demonstrated to have advantageous effects on a number of metabolic pathways as well as the ability to kill liver tumor cells by causing cell death and other routes. This permits us to speculate and make assumptions about the value of BBR in the prevention and defense against NAFLD and HCC by a global modulation of metabolic disorders. Herein, we briefly describe the etiology of NAFLD and NAFLD-related HCC, with a particular emphasis on analyzing the potential mechanisms of BBR in the treatment of NAFLD from aspects including increasing insulin sensitivity, controlling the intestinal milieu, and controlling lipid metabolism. We also elucidate the mechanism of BBR in the treatment of HCC. More significantly, we provided a list of clinical studies for BBR in NAFLD. Taking into account our conclusions and perspectives, we can make further progress in the treatment of BBR in NAFLD and NAFLD-related HCC.

Chinese herbal medicines: The modulator of nonalcoholic fatty liver disease targeting oxidative stress

ETHNOPHARMACOLOGICAL RELEVANCE

Plants are a natural treasure trove; their secondary metabolites participate in several pharmacological processes, making them a crucial component in the synthesis of novel pharmaceuticals and serving as a reserve resource foundation in this process. Nonalcoholic fatty liver disease (NAFLD) is associated with the risk of progression to hepatitis and liver cancer. The "Treatise on Febrile Diseases," "Compendium of Materia Medica," and "Thousand Golden Prescriptions" have listed herbal remedies to treat liver diseases.

AIM OF THE REVIEW

Chinese herbal medicines have been widely used for the prevention and treatment of NAFLD owing to their efficacy and low side effects. The production of reactive oxygen species (ROS) during NAFLD, and the impact and potential mechanism of ROS on the pathogenesis of NAFLD are discussed in this review. Furthermore, common foods and herbs that can be used to prevent NAFLD, as well as the structure-activity relationships and potential mechanisms, are discussed.

METHODS

Web of Science, PubMed, CNKI database, Google Scholar, and WanFang database were searched for natural products that have been used to treat or prevent NAFLD in the past five years. The primary search was performed using the following keywords in different combinations in full articles: NAFLD, herb, natural products, medicine, and ROS. More than 400 research papers and review articles were found and analyzed in this review.

RESULTS

By classifying and discussing the literature, we obtained 86 herbaceous plants, 28 of which were derived from food and 58 from Chinese herbal medicines. The mechanism of NAFLD was proposed through experimental studies on thirteen natural compounds (quercetin, hesperidin, rutin, curcumin, resveratrol, epigallocatechin-3-gallate, salvianolic acid B, paeoniflorin, ginsenoside Rg1, ursolic acid, berberine, honokiol, emodin). The occurrence and progression of NAFLD could be prevented by natural antioxidants through several pathways to prevent ROS accumulation and reduce hepatic cell injuries caused by excessive ROS.

CONCLUSION

This review summarizes the natural products and routinely used herbs (prescription) in the prevention and treatment of NAFLD. Firstly, the mechanisms by which natural products improve NAFLD through antioxidant pathways are elucidated. Secondly, the potential of traditional Chinese medicine theory in improving NAFLD is discussed, highlighting the safety of food-medicine homology and the broader clinical potential of multi-component formulations in improving NAFLD. Aiming to provide theoretical basis for the prevention and treatment of NAFLD.

A scientifically validated combination of garcinol, curcuminoids, and piperine for mild to moderate nonalcoholic steatohepatitis patients-results from a randomized, double-blind, placebo-controlled study

Background

Garcinol is a naturally occurring compound from the fruit rind of the Garcinia indica, with antioxidant, anti-inflammatory, and anticancer properties. Curcuminoids are the active molecule from the rhizome of Curcuma longa, studied extensively for its health benefits as an anti-inflammatory and antioxidant activities. Non-alcoholic steatohepatitis (NASH) is the progressive form of nonalcoholic steatohepatitis characterized by liver fat and inflammation.

Objective

To evaluate the clinical efficacy and safety of Garcinol, Curcuminoids and piperine (GCP) combination in patients with mild to moderate NASH in a randomized, double-blind, placebo-controlled study.

Methods

The patients received one tablet (450 mg) of GCP containing garcinol-50 mg, curcuminoids -250 mg and piperine 5 mg or a placebo (450 mg of microcrystalline cellulose) twice daily for 90 days. Changes in circulating aspartate aminotransferase (AST), alanine transaminase (ALT) levels, liver stiffness measurement (LSM), and controlled attenuation parameter (CAP) using Fibroscan were compared from baseline to day 90. Anthropometric parameters, serum levels of lipids, Interleukin (IL-6), hsCRP, and adiponectin were estimated. Safety was evaluated by laboratory parameters and by monitoring adverse events.

Results

Seventy-two patients were randomized and 63 (GCP = 32, Placebo = 31) completed the study. The mean age of the patients was 48.3 ± 8.7 years (36 males and 27 females). The mean reduction in AST (U/L) was 9.53 in GCP and 3.16 in placebo (p < 0.001) and that of ALT (U/L) was 13.47 in GCP and 7.43 in Placebo (p = 0.002). The liver stiffness and CAP scores showed a better reduction in GCP (0.56 kPa and 12.38 db/m) compared to placebo (0.064 kPa and 10.42 db/m) p < 0.05. Consequently, the noninvasive Fibroscan-AST (FAST) score reduction was also found to be significant in GCP compared to placebo. Additionally, body weight, lipid levels, hsCRP, and IL-6 in serum decreased, while adiponectin levels increased in GCP-supplemented participants compared to placebo. The combination of garcinol and curcuminoids was well tolerated with no significant changes in hematological and clinical laboratory parameters during the 90-day supplementation.

Conclusion

Our results suggest that GCP could be a possible supplement for the management of NASH.Clinical trial registration: https://clinicaltrials.gov/, identifier CTRI/2019/11/022147.

Traditional Chinese medicines and natural products targeting immune cells in the treatment of metabolic-related fatty liver disease

MAFLD stands for metabolic-related fatty liver disease, which is a prevalent liver disease affecting one-third of adults worldwide, and is strongly associated with obesity, hyperlipidemia, and type 2 diabetes. It encompasses a broad spectrum of conditions ranging from simple liver fat accumulation to advanced stages like chronic inflammation, tissue damage, fibrosis, cirrhosis, and even hepatocellular carcinoma. With limited approved drugs for MAFLD, identifying promising drug targets and developing effective treatment strategies is essential. The liver plays a critical role in regulating human immunity, and enriching innate and adaptive immune cells in the liver can significantly improve the pathological state of MAFLD. In the modern era of drug discovery, there is increasing evidence that traditional Chinese medicine prescriptions, natural products and herb components can effectively treat MAFLD. Our study aims to review the current evidence supporting the potential benefits of such treatments, specifically targeting immune cells that are responsible for the pathogenesis of MAFLD. By providing new insights into the development of traditional drugs for the treatment of MAFLD, our findings may pave the way for more effective and targeted therapeutic approaches.

Recent Advances in Anticancer Activity of Novel Plant Extracts and Compounds from Curcuma longa in Hepatocellular Carcinoma

PURPOSE

Among all forms of cancers, hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide. There are several treatment options for HCC ranging from loco-regional therapy to surgical treatment. Yet, there is high morbidity and mortality. Recent research focus has shifted towards more effective and less toxic cancer treatment options. Curcumin, the active ingredient in the Curcuma longa plant, has gained widespread attention in recent years because of its multifunctional properties as an antioxidant, anti-inflammatory, antimicrobial, and anticancer agent.

METHODS

A systematic search of PubMed, Embase and Google Scholar was performed for studies reporting incidence of HCC, risk factors associated with cirrhosis and experimental use of curcumin as an anti-cancer agent.

RESULTS

This review exclusively encompasses the anti-cancer properties of curcumin in HCC globally and it's postulated molecular targets of curcumin when used against liver cancers.

CONCLUSIONS

This review is concluded by presenting the current challenges and future perspectives of novel plant extracts derived from C. longa and the treatment options against cancers.

Developmental Changes of Duckling Liver and Isolation of Primary Hepatocytes

The liver is the main site of fat synthesis and plays an important role in the study of fat deposition in poultry. In this study, we investigated the developmental changes of duckling livers and isolated primary duck hepatocytes. Firstly, we observed morphological changes in duckling livers from the embryonic period to the first week after hatching. Liver weight increased with age. Hematoxylin-eosin and Oil Red O staining analyses showed that hepatic lipids increased gradually during the embryonic period and declined post-hatching. Liver samples were collected from 21-day-old duck embryos for hepatocyte isolation. The hepatocytes showed limited self-renewal and proliferative ability and were maintained in culture for up to 7 days. Typical parenchymal morphology, with a characteristic polygonal shape, appeared after two days of culture. Periodic acid-Schiff (PAS) staining analysis confirmed the characteristics of duck embryo hepatocytes. PCR analysis showed that these cells from duck embryos expressed the liver cell markers ALB and CD36. Immunohistochemical staining and immunofluorescence analysis also confirmed ALB and CK18 expression. Our findings provide a novel insight regarding in vitro cell culture and the characteristics of hepatocytes from avian species, which could enable further studies concerning specific research on duck lipid metabolism.

Antioxidant and anti-inflammatory agents in chronic liver diseases: Molecular mechanisms and therapy

Chronic liver disease (CLD) is a continuous process that causes a reduction of liver function lasting more than six months. CLD includes alcoholic liver disease (ALD), non-alcoholic fatty liver disease (NAFLD), chronic viral infection, and autoimmune hepatitis, which can lead to liver fibrosis, cirrhosis, and cancer. Liver inflammation and oxidative stress are commonly associated with the development and progression of CLD. Molecular signaling pathways such as AMP-activated protein kinase (AMPK), C-Jun N-terminal kinase, and peroxisome proliferator-activated receptors (PPARs) are implicated in the pathogenesis of CLD. Therefore, antioxidant and anti-inflammatory agents from natural products are new potent therapies for ALD, NAFLD, and hepatocellular carcinoma (HCC). In this review, we summarize some powerful products that can be potential applied in all the stages of CLD, from ALD/NAFLD to HCC. The selected agents such as β-sitosterol, curcumin, genistein, and silymarin can regulate the activation of several important molecules, including AMPK, Farnesoid X receptor, nuclear factor erythroid 2-related factor-2, PPARs, phosphatidylinositol-3-kinase, and lysyl oxidase-like proteins. In addition, clinical trials are undergoing to evaluate their efficacy and safety.

The effect of curcumin on hepatic fat content in individuals with obesity

AIM

To evaluate the effect of curcumin treatment on hepatic fat content in obese individuals.

MATERIALS AND METHODS

In a double-blind, parallel-group trial, 37 obese, non-diabetic individuals were randomized to placebo or curcumin treatment for 6 weeks. Curcumin was dosed as lecithin-formulated tablet; 200 mg twice daily. The primary endpoint was hepatic fat content as assessed by magnetic resonance spectroscopy (MRS). Other endpoints included anthropometric measurements, hepatic biomarkers including FibroScan measurements, metabolic variables, inflammation markers, appetite measures and ad libitum food intake.

RESULTS

Baseline characteristics (mean ± SD) were age 46 ± 14 years, hepatic fat content 12.2% ± 8.8% points, body mass index 38.8 ± 6.1 kg/m² and waist circumference 125.8 ± 12.3 cm. After 6 weeks of treatment with curcumin, hepatic fat content was changed by -0.86% points (95% CI -3.65; 1.94) compared with 0.71% points (95% CI - 2.08; 3.51) with placebo, thus resulting in a non-significant estimated treatment difference of -1.57% points (95% CI -5.36; 2.22, P = .412). Compared with placebo, curcumin treatment caused small reductions in fasting plasma glucose (estimated treatment difference [ETD] - 0.24 mmol/L [95% CI -0.45; -0.03]), triglycerides (ETD [percentage change] -20.22% [95% CI -33.21; -6.03]) and gamma glutamyltransferase (ETD [percentage change] -15.70% [95% CI -23.32; -7.32]), but except for gamma glutamyltransferase, none of these differences remained statistically significant after adjusting for multiple testing. Treatment was well tolerated.

CONCLUSIONS

Compared with placebo, curcumin treatment for 6 weeks had no significant effect on MRS-assessed hepatic fat content in obese individuals with primarily mild steatosis. Curcumin was well tolerated.

Dietary Polyphenols Alleviate Autoimmune Liver Disease by Mediating the Intestinal Microenvironment: Challenges and Hopes

Autoimmune liver disease is a chronic liver disease caused by an overactive immune response in the liver that imposes a significant health and economic cost on society. Due to the side effects of existing medicinal medications, there is a trend toward seeking natural bioactive compounds as dietary supplements. Currently, dietary polyphenols have been proven to have the ability to mediate gut-liver immunity and control autoimmune liver disease through modulating the intestinal microenvironment. Based on the preceding, this Review covers the many forms of autoimmune liver illnesses, their pathophysiology, and the modulatory effects of polyphenols on immune disorders. Finally, we focus on how polyphenols interact with the intestinal milieu to improve autoimmune liver disease. In conclusion, we suggest that dietary polyphenols have the potential as gut-targeted modulators for the prevention and treatment of autoimmune liver disease and highlight new perspectives and critical issues for future pharmacological applications.

Sexual dimorphism modulates metabolic and cognitive alterations under HFD nutrition and chronic stress exposure in mice. Correlation between spatial memory impairment and BDNF mRNA expression in hippocampus and spleen

AIMS

The accumulated evidence suggests that lifestyle - specifically dietary habits and stress exposure - plays a detrimental role in health. The purpose of the present study was to analyze the interplay of stress, diet, and sex in metabolic and cognitive alterations.

MAIN METHODS

For this purpose, one-month-old C57Bl/6J mice were fed with a standard diet or high-fat diet (HFD). After eight weeks, one subgroup of mice from each respective diet was exposed to 20 weeks of chronic mild stress (CMS), whilst the others were left undisturbed.

KEY FINDINGS

After 28 weeks of HFD feeding, mice from both sexes were overweight, with an increase in caloric intake and abdominal and subcutaneous fat pads. Stress exposure induced a decrease in body weight, related to a decrease in caloric efficiency in both males and females. Results indicate that males are more susceptible than the females in modulating metabolic and cognitive functions under HFD and CMS. Although both sexes demonstrated HFD-induced weight gain, fat accumulation, insulin resistance, high cholesterol, only males exposed to CMS but not females have (i) impaired glucose tolerance with higher glucose level; (ii) significant prolonged latency in Barnes test, suggesting cognitive impairment; (iii) increased IFN-gamma expression in hippocampus, suggesting greater neuroinflammatory response; (iv) poorer cognitive performance related to a decrease in hippocampal and spleen BDNF mRNA expression.

SIGNIFICANCE

The main finding in this study is the presence of a sexual dimorphism in modulating metabolic and cognitive functions under HFD and CMS, showing males are more susceptible than females. In addition, poorer cognitive performance was related to a decrease in hippocampal BDNF mRNA expression. Interestingly, these changes were observed in the spleen as well.

Targeted therapeutics and novel signaling pathways in non-alcohol-associated fatty liver/steatohepatitis (NAFL/NASH)

Non-alcohol-associated fatty liver/steatohepatitis (NAFL/NASH) has become the leading cause of liver disease worldwide. NASH, an advanced form of NAFL, can be progressive and more susceptible to developing cirrhosis and hepatocellular carcinoma. Currently, lifestyle interventions are the most essential and effective strategies for preventing and controlling NAFL without the development of fibrosis. While there are still limited appropriate drugs specifically to treat NAFL/NASH, growing progress is being seen in elucidating the pathogenesis and identifying therapeutic targets. In this review, we discussed recent developments in etiology and prospective therapeutic targets, as well as pharmacological candidates in pre/clinical trials and patents, with a focus on diabetes, hepatic lipid metabolism, inflammation, and fibrosis. Importantly, growing evidence elucidates that the disruption of the gut-liver axis and microbe-derived metabolites drive the pathogenesis of NAFL/NASH. Extracellular vesicles (EVs) act as a signaling mediator, resulting in lipid accumulation, macrophage and hepatic stellate cell activation, further promoting inflammation and liver fibrosis progression during the development of NAFL/NASH. Targeting gut microbiota or EVs may serve as new strategies for the treatment of NAFL/NASH. Finally, other mechanisms, such as cell therapy and genetic approaches, also have enormous therapeutic potential. Incorporating drugs with different mechanisms and personalized medicine may improve the efficacy to better benefit patients with NAFL/NASH.

A Decreased Response to Resistin in Mononuclear Leukocytes Contributes to Oxidative Stress in Nonalcoholic Fatty Liver Disease

BACKGROUND

Deregulation of immune response and oxidative stress contribute to nonalcoholic fatty liver disease (NAFLD) pathogenesis. Resistin is a physiological modulator of inflammation and redox homeostasis of different cell types. Increased resistin serum concentration and the direct association between resistin hepatic expression and NAFLD severity suggest that resistin participates in NAFLD pathogenesis.

AIMS

To evaluate resistin-induced regulation of redox homeostasis in mononuclear leukocytes from NAFLD patients and controls.

METHODS

We evaluated basal and resistin-mediated modulation of reactive oxygen species (ROS) and glutathione content by flow cytometry, and antioxidant enzyme activities by spectrophotometry.

RESULTS

Peripheral blood mononuclear cells (PBMC) from NAFLD patients showed higher ROS content and glutathione peroxidase activity and lower glutathione content, superoxide dismutase and glutathione reductase activities than control PBMC. Resistin decreased ROS levels and superoxide dismutase activity and increased glutathione reductase and catalase activities in PBMC from controls but not from patients. Resistin decreased glutathione content in PBMC from control and NAFLD patients, with greater effect on patient cells. Basal and resistin-modulated ROS levels were directly associated with obesity-related risk factors for NAFLD. Hepatic myeloid cells and T-lymphocytes from NAFLD patients showed higher basal ROS content than cells from controls. Resistin decreased ROS levels in hepatic T-lymphocytes from controls but not from patients.

CONCLUSIONS

Resistin regulates redox homeostasis in mononuclear leukocytes. A decreased response to resistin in leukocytes from NAFLD patients is associated with an impaired redox homeostasis.

A Comprehensive Review on the Therapeutic Potential of Curcuma longa Linn. in Relation to its Major Active Constituent Curcumin

Curcuma longa Linn. (C. longa), popularly known as turmeric, belongs to the Zingiberaceae family and has a long historical background of having healing properties against many diseases. In Unani and Ayurveda medicine, C. longa has been used for liver obstruction and jaundice, and has been applied externally for ulcers and inflammation. Additionally, it is employed in several other ailments such as cough, cold, dental issues, indigestion, skin infections, blood purification, asthma, piles, bronchitis, tumor, wounds, and hepatic disorders, and is used as an antiseptic. Curcumin, a major constituent of C. longa, is well known for its therapeutic potential in numerous disorders. However, there is a lack of literature on the therapeutic potential of C. longa in contrast to curcumin. Hence, the present review aimed to provide in-depth information by highlighting knowledge gaps in traditional and scientific evidence about C. longa in relation to curcumin. The relationship to one another in terms of biological action includes their antioxidant, anti-inflammatory, neuroprotective, anticancer, hepatoprotective, cardioprotective, immunomodulatory, antifertility, antimicrobial, antiallergic, antidermatophytic, and antidepressant properties. Furthermore, in-depth discussion of C. longa on its taxonomic categorization, traditional uses, botanical description, phytochemical ingredients, pharmacology, toxicity, and safety aspects in relation to its major compound curcumin is needed to explore the trends and perspectives for future research. Considering all of the promising evidence to date, there is still a lack of supportive evidence especially from clinical trials on the adjunct use of C. longa and curcumin. This prompts further preclinical and clinical investigations on curcumin.

Crucial role of T cells in NAFLD-related disease: A review and prospect

Nonalcoholic fatty liver disease (NAFLD) includes a series of hepatic manifestations, starting with liver steatosis and potentially evolving towards nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis or even hepatocellular carcinoma (HCC). Its incidence is increasing worldwide. Several factors including metabolic dysfunction, oxidative stress, lipotoxicity contribute to the liver inflammation. Several immune cell-mediated inflammatory processes are involved in NAFLD in which T cells play a crucial part in the progression of the disease. In this review, we focus on the role of different subsets of both conventional and unconventional T cells in pathogenesis of NAFLD. Factors regarding inflammation and potential therapeutic approaches targeting immune cells in NASH are also discussed.

Oxidative Stress Is a Key Modulator in the Development of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide, and scientific studies consistently report that NAFLD development can be accelerated by oxidative stress. Oxidative stress can induce the progression of NAFLD to NASH by stimulating Kupffer cells, hepatic stellate cells, and hepatocytes. Therefore, studies are underway to identify the role of antioxidants in the treatment of NAFLD. In this review, we have summarized the origins of reactive oxygen species (ROS) in cells, the relationship between ROS and NAFLD, and have discussed the use of antioxidants as therapeutic agents for NAFLD.

Design of Hepatic Targeted Drug Delivery Systems for Natural Products: Insights into Nomenclature Revision of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD), recently renamed metabolic-dysfunction-associated fatty liver disease (MAFLD), affects a quarter of the worldwide population. Natural products have been extensively utilized in treating NAFLD because of their distinctive advantages over chemotherapeutic drugs, despite the fact that there are no approved drugs for therapy. Notably, the limitations of many natural products, such as poor water solubility, low bioavailability in vivo, low hepatic distribution, and lack of targeted effects, have severely restricted their clinical application. These issues could be resolved via hepatic targeted drug delivery systems (HTDDS) that boost clinical efficacy in treating NAFLD and decrease the adverse effects on other organs. Herein an overview of natural products comprising formulas, single medicinal plants, and their crude extracts has been presented to treat NAFLD. Also, the clinical efficacy and molecular mechanism of active monomer compounds against NAFLD are systematically discussed. The targeted delivery of natural products via HTDDS has been explored to provide a different nanotechnology-based NAFLD treatment strategy and to make suggestions for natural-product-based targeted nanocarrier design. Finally, the challenges and opportunities put forth by the nomenclature update of NAFLD are outlined along with insights into how to improve the NAFLD therapy and how to design more rigorous nanocarriers for the HTDDS. In brief, we summarize the up-to-date developments of the NAFLD-HTDDS based on natural products and provide viewpoints for the establishment of more stringent anti-NAFLD natural-product-targeted nanoformulations.

Improving the ameliorative effects of berberine and curcumin combination via dextran-coated bilosomes on non-alcohol fatty liver disease in mice

BACKGROUND

The combination of berberine (BER) and curcumin (CUR) has been verified with ameliorative effects on non-alcohol fatty liver disease (NAFLD). However, discrepant bioavailability and biodistribution of BER and CUR remained an obstacle to achieve synergistic effects. Multilayer nanovesicles have great potential for the protection and oral delivery of drug combinations. Therein lies bile salts inserted liposomes, named as bilosomes, that possesses long residence time in the gastrointestinal tract (GIT) and permeability across the small intestine. Diethylaminoethyl dextran (DEAE-DEX) is generally used as an outside layer on the nanovesicles to increase the mucinous stability and promote oral absorption. Herein, we developed a DEAE-DEX-coated bilosome with BER and CUR encapsulated (DEAE-DEX@LSDBC) for the treatment of NAFLD.

RESULTS

DEAE-DEX@LSDBC with 150 nm size exhibited enhanced permeation across mucus and Caco-2 monolayer. In vivo pharmacokinetics study demonstrated that DEAE-DEX@LSDBC profoundly prolonged the circulation time and improved the oral absorption of both BER and CUR. Intriguingly, synchronized biodistribution of BER and CUR and highest biodistribution at liver was achieved by DEAE-DEX@LSDBC, which contributed to the optimal ameliorative effects on NAFLD. It was further verified to be mainly mediated by anti-oxidation and anti-inflammation related pathways CONCLUSION: DEAE-DEX coated bilosome displayed promoted oral absorption, prolonged circulation and synchronized biodistribution of BER and CUR, leading to improved ameliorative effects on NAFLD in mice, which provided a promising strategy for oral administration of drug combinations.

Comparing the Protective Effects of Curcumin and Ursodeoxycholic Acid after Ethanol-Induced Hepatotoxicity in Rat Liver

BACKGROUND

Alcohol consumption can cause hepatitis and long-term cirrhosis of the liver. The aim of this study was to evaluate the protective effects of curcumin (CUR) and ursodeoxycholic acid (UDCA) alone and together in the prevention and treatment of liver damage caused by overuse of ethanol.

METHODS

Adult Wistar rats were divided into 8 groups of 5, including the control group and various combinations of ethanol, CUR and UDCA groups. Twenty-eight days after the oral treatment, serum levels of aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT) and Arginase I (ArgI) as well as serum levels of Albumin (Alb), total protein (TP) and Blood Urea Nitrogen (BUN) were measured, and liver tissue was evaluated histopathologically.

RESULTS

The solo administration of CUR, UDCA and CUR+UDCA had no effect on the blood parameters and liver tissue compared to the control group (p>0.05). The solo administration of CUR and UDCA in ethanol-treated rats significantly reduced ALT, AST, ALP, GGT, ArgI and BUN levels (p<0.05), while the solo administration increased Alb and TP levels compared to the ethanol group (p<0.05). In these groups, a significant decrease in cell necrosis and local inflammation of hepatocytes was observed, and the liver damage was mild. However, co-administration of ethanol, CUR and UDCA made significantly greater decrease in ALT, AST, ALP, GGT, ArgI and BUN levels (p>0.05), while the co-administration greatly increased Alb and TP levels compared to the ethanol group (p<0.05). Histopathologically, a decrease in structural changes in liver tissue and inflammation was observed, resulting in the improvement of liver tissue.

CONCLUSION

The solo administration of CUR and UDCA could reduce ethanol-induced liver damage in rats and improve liver's serum and blood parameters. However, the coadministration of CUR and UDCA has a greater efficacy.

Immunomodulatory Effects and Mechanisms of Curcuma Species and Their Bioactive Compounds: A Review

Curcuma species (family: Zingiberaceae) are widely utilized in traditional medicine to treat diverse immune-related disorders. There have been many scientific studies on their immunomodulating effects to support their ethnopharmacological uses. In this review, the efficacy of six Curcuma species, namely, C. longa L., C. zanthorrhiza Roxb., C. mangga Valeton & Zijp, C. aeruginosa Roxb. C. zedoaria (Christm.) Roscoe, and C. amada Roxb., and their bioactive metabolites to modulate the immune system, their mechanistic effects, and their potential to be developed into effective and safe immunomodulatory agents are highlighted. Literature search has been carried out extensively to gather significant findings on immunomodulating activities of these plants. The immunomodulatory effects of Curcuma species were critically analyzed, and future research strategies and appropriate perspectives on the plants as source of new immunomodulators were discussed. Most of the pharmacological investigations to evaluate their immunomodulatory effects were in vivo and in vitro experiments on the crude extracts of the plants. The extracts were not chemically characterized or standardized. Of all the Curcuma species investigated, the immunomodulatory effects of C. longa were the most studied. Most of the bioactive metabolites responsible for the immunomodulating activities were not determined, and mechanistic studies to understand the underlying mechanisms were scanty. There are limited clinical studies to confirm their efficacy in human. Of all the bioactive metabolites, only curcumin is undergoing extensive clinical trials based on its anti-inflammatory properties and main use as an adjuvant for the treatment of cancer. More in-depth studies to understand the underlying mechanisms using experimental in vivo animal models of immune-related disorders and elaborate bioavailability, preclinical pharmacokinetics, and toxicity studies are required before clinical trials can be pursued for development into immunomodulatory agents.

Effect of Curcumin Nanoemulsions Stabilized with MAG and DAG-MCFAs in a Fructose-Induced Hepatic Steatosis Rat Model

Current changes in diet, characterized by an increase in the intake of sweetened beverages, are heavily related to metabolic disorders such as non-alcoholic fatty liver. This condition can produce simple steatosis and, in worse cases, potentially result in steatohepatitis, fibrosis, and cirrhosis, comparable to the damage caused by the consumption of more or less 20–30 g of alcohol per day. The main objective of this research was to evaluate the effect of curcumin (Curcuma longa) nanoemulsions, using mono- and diacylglycerides medium chain fatty acids as stabilizers in an in vivo hepatic steatosis rat model. Pathology was induced by providing 30% fructose intake in the drinking water. Globule sizes under 200 nm that were stable for 4 weeks were obtained; curcumin encapsulated in the nanoemulsion was >70%. The results revealed an improvement regarding body and liver weight in the animals treated with curcumin nanoemulsions. A decrease in total cholesterol, LDL, AST/ALT, and HDL in serum was observed; however, no apparent improvement regarding serum glucose or triacylglycerides values was noted. Histological analysis showed a significant decrease in the extent of steatosis, inflammation, and brown adipose tissue in the treated animals.

Innate and Adaptive Immunity Alterations in Metabolic Associated Fatty Liver Disease and Its Implication in COVID-19 Severity

The coronavirus infectious disease 2019 (COVID-19) pandemic has hit the world, affecting health, medical care, economies and our society as a whole. Furthermore, COVID-19 pandemic joins the increasing prevalence of metabolic syndrome in western countries. Patients suffering from obesity, type II diabetes mellitus, cardiac involvement and metabolic associated fatty liver disease (MAFLD) have enhanced risk of suffering severe COVID-19 and mortality. Importantly, up to 25% of the population in western countries is susceptible of suffering from both MAFLD and COVID-19, while none approved treatment is currently available for any of them. Moreover, it is well known that exacerbated innate immune responses are key in the development of the most severe stages of MAFLD and COVID-19. In this review, we focus on the role of the immune system in the establishment and progression of MAFLD and discuss its potential implication in the development of severe COVID-19 in MAFLD patients. As a result, we hope to clarify their common pathology, but also uncover new potential therapeutic targets and prognostic biomarkers for further research.

Potential therapeutic applications of phytoconstituents as immunomodulators: Pre-clinical and clinical evidences

Autoimmune and infectious diseases are the major public health issues and have gained great attention in the last few years for the search of new agents with therapeutic benefits on the host immune functions. In recent years, natural products (NPs) have been studied broadly for their multi-targeted activities under pathological conditions. Interestingly, several attempts have been made to outline the immunomodulatory properties of NPs. Research on in-vitro and in-vivo models have shown the immunomodulatory activity of NPs, is due to their antiinflammatory property, induction of phagocytosis and immune cells stimulation activity. Moreover, studies on humans have suggested that phytomedicines reduce inflammation and could provide appropriate benefits either in single form or complex combinations with other agents preventing disease progression, subsequently enhancing the efficacy of treatment to combat multiple malignancies. However, the exact mechanism of immunomodulation is far from clear, warranting more detailed investigations on their effectiveness. Nevertheless, the reduction of inflammatory cascades is considered as a prime protective mechanism in a number of inflammation regulated autoimmune diseases. Altogether, this review will discuss the biological activities of plant-derived secondary metabolites, such as polyphenols, alkaloids, saponins, polysaccharides and so forth, against various diseases and their potential use as an immunomodulatory agent under pathological conditions.

Plant-Based Foods and Their Bioactive Compounds on Fatty Liver Disease: Effects, Mechanisms, and Clinical Application

Fatty liver disease (FLD), including nonalcoholic fatty liver disease (NAFLD) and alcoholic fatty liver disease (AFLD), is a serious chronic metabolic disease that affects a wide range of people. Lipid accumulation accompanied by oxidative stress and inflammation in the liver is the most important pathogenesis of FLD. The plant-based, high-fiber, and low-fat diet has been recommended to manage FLD for a long time. This review discusses the current state of the art into the effects, mechanisms, and clinical application of plant-based foods in NAFLD and AFLD, with highlighting related molecular mechanisms. Epidemiological evidence revealed that the consumption of several plant-based foods was beneficial to alleviating FLD. Further experimental studies found out that fruits, spices, teas, coffee, and other plants, as well as their bioactive compounds, such as resveratrol, anthocyanin, curcumin, and tea polyphenols, could alleviate FLD by ameliorating hepatic steatosis, oxidative stress, inflammation, gut dysbiosis, and apoptosis, as well as regulating autophagy and ethanol metabolism. More importantly, clinical trials confirmed the beneficial effects of plant-based foods on patients with fatty liver. However, several issues need to be further studied especially the safety and effective doses of plant-based foods and their bioactive compounds. Overall, certain plant-based foods are promising natural sources of bioactive compounds to prevent and alleviate fatty liver disease.

Hepatic steatosis integrated approach: nutritional guidelines and joined nutraceutical administration

BACKGROUND

The nonalcoholic fat liver disease (NAFLD) progresses in 30% of the patients to not alcoholic steatohepatitis (NASH) and subsequently in liver fibrosis and even primary cancer and death. Due to the complex physiopathology of the liver steatosis, NASH is an area orphan of specific drugs, but many authors suggest an integrated treatment based upon diet, lifestyle change, and pharmacology.

METHODS

Our clinical study selected from a wider patient cohort, 13 subjects, appealing to the Second Opinion Medical Consulting Network, for liver and nutritional problems. The diet was integrated with regular prescription of an herbal derivative based on Chrysanthellum americanum and Pistacia lentiscus L. extracts. Clinical data of the recruited patients including body weight, Body Mass Index, were recorded before and after treatment. Each patient underwent pre-post accurate clinical examination and lab exams. The liver stiffness and liver steatosis were evaluated by a trained hepatologist with FibroScan^®.

RESULTS

A significant reduction of anthropometric parameters was detected in all the patients at the end of the study; liver fibrosis and steatosis were instrumentally decreased in 8 subjects, but not significant changes in lab exams and no adverse effects were reported.

CONCLUSIONS

Chrysanthellum americanum and Pistacia lentiscus L. extracts were absolutely safe and effective and gave a substantial contribution to the life quality benefit, metabolic balance and gut function in patients with hepatic steatosis.

Curcumin and Piperine Combination for the Treatment of Patients with Non-alcoholic Fatty Liver Disease: A Double-Blind Randomized Placebo-Controlled Trial

BACKGROUND

Experimental and clinical studies have revealed that curcumin may be an effective therapy for non-alcoholic fatty liver disease (NAFLD). Hence, the aim of this study was to assess the effect of curcumin plus piperine administration on NAFLD.

METHODS

Adults 18-65 years-old diagnosed with NAFLD by liver sonography were randomly allocated to curcumin (500 mg/day) or placebo groups for 2 months. All participants received both dietary and exercise advice. Anthropometric and biochemical measurements as well as hepatic ultrasound were performed at baseline and final conditions.

RESULTS

Seventy-nine participants were recruited and randomly allocated into the curcumin (n = 39) or placebo (n = 40) groups. There were no significant differences between placebo and curcumin groups for demographic and clinical characteristics and NAFLD grade at baseline. After the treatment period, the curcumin group exhibited lower alkaline phosphatase (-16.2 ± 22.8 versus -6.0 ± 22.5 mg/dL, p = 0.04) concentrations and severity of NAFLD compared with the placebo group (p = 0.04).

CONCLUSION

Results of this clinical trial suggest that short-term treatment with curcumin plus piperine administration improves NAFLD severity.

Beneficial Effects of Plant-Derived Natural Products on Non-alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease is becoming in one of the most prevalent liver diseases that leads to liver transplantation. This health problem is a multisystem disease with a complex pathogenesis that involves liver, adipose tissue, gut, and muscle. Although several pharmacological agents have been investigated to prevent or treat non-alcoholic fatty liver disease, currently there is no effective treatment for the management of this chronic liver disease. Nonetheless, the use of natural products has emerged as a alternative therapeutic for the treatment of hepatic diseases, including non-alcoholic fatty liver disease, due to its anti-inflammatory, antioxidant, antidiabetic, insulin-sensitizing, antiobesity, hypolipidemic, and hepatoprotective properties. In the present review, we have discussed the evidence from experimental and clinical studies regarding the potential beneficial effects of plant-derived natural products (quercetin, resveratrol, berberine, pomegranate, curcumin, cinnamon, green tea, coffee, garlic, ginger, ginseng, and gingko biloba) for the treatment or prevention of non-alcoholic fatty liver disease.

Effect of sour tea supplementation on liver enzymes, lipid profile, blood pressure, and antioxidant status in patients with non-alcoholic fatty liver disease: A double-blind randomized controlled clinical trial

The aim of this study was to evaluate the efficacy of sour tea supplementation in patients with nonalcoholic fatty liver disease (NAFLD). Seventy NAFLD patients were enrolled in this randomized, double-blind, placebo-controlled clinical trial. Participants received sour tea in the form of a 450 mg capsule or a placebo capsule daily for 8 weeks. Anthropometric indices, liver enzymes, lipid profile, blood pressure, and antioxidant status were evaluated at the baseline and at the end of the study. Sixty-one participants completed the study. After 8 weeks, sour tea administration significantly decreased serum triglyceride (TG) (p = .03), alanine aminotransferase (ALT) (p = .01), and aspartate aminotransferase (AST) (p = .004) levels compared with the placebo. In addition, sour tea supplementation resulted in a significant reduction in systolic blood pressure (SBP) (p = .03) and diastolic blood pressure (DBP) (p = .04), and a significant increase in serum total antioxidant capacity (TAC) levels (p ˂ .001) compared with the placebo. However, no significant changes in anthropometric measures, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), and high-density lipoprotein cholesterol (HDL-c) levels were observed after sour tea supplementation compared with the placebo (p > .05). Sour tea supplementation may be effective in improving serum TG, liver enzymes, and blood pressure in patients diagnosed with NAFLD. Further studies are needed to address the exact mechanism of action of these effects.

The long-term protective effects of neonatal administration of curcumin against nonalcoholic steatohepatitis in high-fructose-fed adolescent rats

There is an increased prevalence of nonalcoholic steatohepatitis (NASH) in adolescents. The suckling period is developmentally plastic, affecting later health outcomes. We investigated whether neonatal administration of curcumin would provide protection against the development of NASH later in adolescence in rats fed a high-fructose diet. From postnatal day (PN) 6 to PN 21, the pups (N = 128) were allocated to four groups and orally gavaged daily with either 0.5% dimethyl sulfoxide solution (vehicle control), curcumin (500 mg·kg^-1 ), fructose (20%, w/v) or curcumin and fructose combined. All the pups were weaned and half the rats in each group had tap water, whereas the other received fructose (20%) as their drinking fluid ad libitum for 6 weeks. The rats' liver NASH scores, lipid content, and RNA gene expression ratios of AMPKα and TNFα were determined. Hepatic lipid content was similar across the treatment groups in the males (P > 0.05, ANOVA). In the females, the hepatic lipid content in the treatment groups ranged from 2.7 to 4.3%. The livers of male and female rats that had fructose either as neonates and/or postweaning had significantly marked inflammation (P = 0.0112, Kruskal-Wallis) and fibrosis (P < 0.0001, ANOVA) which were attenuated by curcumin. The hepatic gene expression ratios for AMPKα in both sexes were significantly downregulated (P < 0.0001, ANOVA), whereas the expression ratios of TNFα were significantly upregulated (P < 0.0001) in rats fed a high-fructose diet pre and/or postweaning compared to the other groups. Neonatal curcumin administration is a potential natural pharmacological candidate for the prevention of NASH.

Theaflavin TF3 Relieves Hepatocyte Lipid Deposition through Activating an AMPK Signaling Pathway by targeting Plasma Kallikrein

Nonalcoholic fatty liver disease (NAFLD) is rapidly becoming the leading cause of chronic liver diseases throughout the world. The deficit of pharmacotherapy for NAFLD calls for an urgent need for a new drug discovery and lifestyle management. Black tea is the most popular and functional drink consumed worldwide. Its main bioactive constituent theaflavin helps to prevent obesity-a major risk factor for NAFLD. To find new targets for the development of effective and safe therapeutic drugs from natural plants for NAFLD, we found a theaflavin monomer theaflavin-3,3'-digallate (TF3), which significantly reduced lipid droplet accumulation in hepatocytes, and directly bound and inhibited the activation of plasma kallikrein (PK), which was further proved to stimulate adenosine monophosphate activated protein kinase (AMPK) and its downstream targets. Taken together, we proposed that the TF3-PK-AMPK regulatory axis is a novel mechanism of lipid deposition mitigation, and PK could be a new target for NAFLD treatment.

Bisdemethoxycurcumin attenuates cisplatin-induced renal injury through anti-apoptosis, anti-oxidant and anti-inflammatory

Cisplatin is a widely used chemotherapy drug that is first-line therapy for a variety of tumors. Unfortunately, its adverse effects on various normal tissues and organs, especially nephrotoxicity, threaten the life of patients. Although the mechanism of cisplatin nephrotoxicity has been confirmed to be related to oxidative stress, apoptosis of renal tubular epithelial cells and inflammatory response, there is no effective prevention strategy in the clinic. Here, we found that bisdemethoxycurcumin (BDMC), a natural compound, can significantly attenuates cisplatin-induced apoptosis of renal tubular epithelial cells in vitro at the concentration of 5-20 μM and has a significant protective effect on cisplatin-induced kidney injury in mice at the dose of 50 mg/kg. Mechanistically, BDMC attenuates cisplatin-induced apoptosis of renal tubular epithelial cells by inhibiting cisplatin-induced up-regulation of p53. Meanwhile, BDMC counteracts oxidative stress by inhibiting cisplatin-induced down-regulation of nuclear factor erythroid-2-related factor 2 (Nrf2). BDMC also significantly reduced the expression of intercellular adhesion molecule-1 (ICAM-1) and monocyte chemoattractant protein-1 (MCP-1) proteins, as well as the expression and translocation of the p65 subunit of nuclear factor-κB (NF-κB p65) into the nucleus, all of which were increased in the kidney by cisplatin treatment. Collectively, BDMC might be an effective prevention strategy which could against cisplatin-induced nephrotoxicity, and our research may shed a new light on treatment of drug toxicity.

Curcumin analog CUR5-8 ameliorates nonalcoholic fatty liver disease in mice with high-fat diet-induced obesity

OBJECTIVE

Nonalcoholic fatty liver disease (NAFLD) occurs when excess fat storage in the liver and it is strongly linked with metabolic syndrome including obesity, insulin resistance, dyslipidemia and hypertension. Curcumin5-8 (CUR5-8) is a synthetic derivative of naturally active curcumin (CUR) that has anti-oxidative and anti-inflammatory properties. In the present study, we investigated the effects of CUR5-8, a novel CUR analog, on hepatic steatosis in mice with high-fat diet (HFD)-induced obesity.

METHODS

Based on their diets for 13 weeks, the mice were categorized into the following six groups: regular diet (RD, n = 10), RD with CUR (RD + CUR, 100 mg/kg/day, n = 10), RD with CUR5-8 (RD + CUR5-8, 100 mg/kg/day, n = 10), high-fat diet-induced obese mice (HFD, n = 10), HFD with CUR (HFD + CUR, 100 mg/kg/day, n = 10), and HFD with CUR5-8 (HFD + CUR5-8, 100 mg/kg/day, n = 10) for 13 weeks. Hematoxylin and eosin (H&E) staining of the sections revealed hepatic steatosis.

RESULTS

CUR5-8 administration prevented increase in body and liver weights in mice with HFD-induced obesity. Compared to the HFD group, insulin resistance was significantly improved in the HFD + CUR5-8 group. Serum alanine aminotransferase level, which is an indicator of liver damage, was also decreased after CUR5-8 administration. H&E staining revealed that CUR5-8 treatment decreased hepatic steatosis in mice with HFD-induced obesity. Interestingly, CUR5-8, and not CUR, decreased the elevated liver triglyceride level induced by the HFD.

CONCLUSIONS

These findings suggest that CUR5-8 ameliorates insulin resistance and hepatic steatosis in mice with HFD-induced obesity.

Limited expression of TLR9 on T cells and its functional consequences in patients with nonalcoholic fatty liver disease

Background/Aims

Toll-like receptors (TLRs) modulate T cell responses in diverse diseases. Co-stimulation of T cell activation via TLR9 induces production of interferon gamma (IFN-γ), priming of which is critical for differentiation of pro-inflammatory macrophages. These macrophages have a crucial role in nonalcoholic fatty liver disease (NAFLD). We aimed to evaluate the expression of TLR9 protein on T cells and the consequences of TLR9-mediated triggering of these cells in patients with NAFLD.

Methods

Our study included 34 patients with simple steatosis, 34 patients with nonalcoholic steatohepatitis, eight patients with NAFLD who met general diagnostic criteria but lacked histological diagnosis, and 51 control subjects. We used a synthetic TLR9 ligand to co-stimulate T cells. We measured TLR9 expression in liver and peripheral T cells and CD69 and IFN-γ as phenotypic markers of T cell activation and differentiation by flow cytometry.

Results

TLR9 expression on liver and peripheral T cells was lowest in patients with simple steatosis and was positively associated with anthropometric, biochemical, and histopathological features of NAFLD. In vitro co-stimulation of T cells from patients with simple steatosis induced a limited number of IFN-γ-producing CD8⁺ T cells. At baseline, these patients showed a low frequency of circulating type 1 CD8⁺ cells.

Conclusions

The positive associations between TLR9 and anthropometric, clinical, and histological features and the crucial role of IFN-γ-in NAFLD suggest that limited TLR9 expression and production of IFN-γ play a protective role in patients with simple steatosis.

Resveratrol Maintains Lipid Metabolism Homeostasis via One of the Mechanisms Associated with the Key Circadian Regulator Bmal1

Resveratrol (RES) possesses anti-inflammatory and anti-oxidant activities, and it can prevent liver lipid metabolism disorders in obese and diabetic individuals. This study elucidated the mechanisms of brain and muscle Arnt-like protein-1 (Bmal1) in the protective effects of RES against liver lipid metabolism disorders. The results indicated that RES ameliorated free fatty acid (FFA)-induced (oleic acid (OA): palmitic acid (PA) = 2:1) glycolipid metabolic disorders in hepatocytes. Simultaneously, RES partially reverted the relatively shallow daily oscillations of FFA-induced circadian clock gene transcription and protein expression in HepG2 cells. RES also attenuated FFA-triggered reactive oxygen species (ROS) secretion and restored mitochondrial membrane potential consumption, as well as the restoration of mitochondrial respiratory complex expression. This study provides compelling evidence that RES controls intracellular lipid metabolic imbalance in a Bmal1-dependent manner. Overall, RES may serve as a promising natural nutraceutical for the regulation of lipid metabolic disorders relevant to the circadian clock.

A Review of Biologically Active Natural Products from a Desert Plant Cistanche tubulosa

An Orobanchaceae plant Cistanche tubulosa (SCHENK) WIGHT (Kanka-nikujuyou in Japanese), which is one of the authorized plant resources as Cistanches Herba in both Japanese and Chinese Pharmacopoeias, is a perennial parasitic plant growing on roots of sand-fixing plants. The stems of C. tubulosa have traditionally been used for treatment of impotence, sterility, lumbago, and body weakness as well as a promoting agent of blood circulation. In recent years, Cistanches Herba has also been widely used as a health food supplement in Japan, China, and Southeast Asian countries. Here we review our recent studies on chemical constituents from the stems of C. tubulosa as well as their bioactivities such as vasorelaxtant, hepatoprotective, and glucose tolerance improving effects.

Bioactivity, Health Benefits, and Related Molecular Mechanisms of Curcumin: Current Progress, Challenges, and Perspectives

Curcumin is a principal curcuminoid of turmeric (Curcuma longa), which is commonly used as a spice in cooking and a yellow pigment in the food processing industry. Recent studies have demonstrated that curcumin has a variety of biological activities and pharmacological performances, providing protection and promotion of human health. In addition to presenting an overview of the gut metabolism of curcumin, this paper reviews the current research progress on its versatile bioactivity, such as antioxidant, anti-inflammatory, and immune-regulatory activities, and also intensively discusses its health benefits, including the protective or preventive effects on cancers and diabetes, as well as the liver, nervous system, and cardiovascular systems, highlighting the potential molecular mechanisms. Besides, the beneficial effects of curcumin on human are further stated based on clinical trials. Considering that there is still a debate on the beneficial effects of curcumin, we also discuss related challenges and prospects. Overall, curcumin is a promising ingredient of novel functional foods, with protective efficacy in preventing certain diseases. We hope this comprehensive and updated review will be helpful for promoting human-based studies to facilitate its use in human health and diseases in the future.

Cichoric Acid Prevents Free-Fatty-Acid-Induced Lipid Metabolism Disorders via Regulating Bmal1 in HepG2 Cells

Cichoric acid (CA), a polyphenol component from Echinacea purpurea, exhibits preventive effects on liver lipid-metabolism disorders in obesity. This research aimed to determine the role of circadian rhythm signaling during the process of CA-attenuated lipid accumulation in hepatocytes. In the current study, CA treatments improved cell morphology changes and hepatic lipid levels, which were triggered by free fatty acids (2:1, oleate: palmitate) in a dose-dependent way. Besides, CA (200 μM) regulated the circadian rhythm expressions of clock genes and the relatively shallow daily oscillations. Moreover, silencing Bmal1 significantly blocked the p-Akt/Akt pathway to 80.1% ± 1.5% and the p-GSK3β/GSK3β pathway to 64.7% ± 2.8% ( p < 0.05). Furthermore, silencing Bmal1 elevated the expressions of FAS and ACC to 122.4% ± 5.6% and 114.9% ± 1.7% in protein levels ( p < 0.05) and to 166.5% ± 18.5% and 131.4% ± 5.5% in mRNA levels ( p < 0.05). Therefore, our results demonstrated that CA has a Bmal1 resistance to lipid accumulation by enhancing the Akt/GSK3β signaling pathways and modulating the downstream expressions related to lipid metabolism, which indicated that CA might be useful as a natural and promising nonalcoholic fatty liver diseases (NAFLD) modulator.

Potential Therapeutic Benefits of Herbs and Supplements in Patients with NAFLD

Our aim is to review the efficacy of various herbs and supplements as a possible therapeutic option in the treatment and/or prevention of nonalcoholic fatty liver disease (NAFLD). We performed a systematic review of medical literature using the PubMed Database by searching the chemical names of many common herbs and supplements with “AND (NAFLD or NASH)”. Studies and medical literature that discussed the roles and usage of herbs and supplements in NAFLD and nonalcoholic steatohepatitis (NASH) from inception until 20 June 2018 were reviewed. Many studies have claimed that the use of various herbs and supplements may improve disease endpoints and outcomes related to NAFLD and/or NASH. Improvement in liver function tests were noted. Amelioration or reduction of lobular inflammation, hepatic steatosis, and fibrosis were also noted. However, well-designed studies demonstrating improved clinical outcomes are lacking. Furthermore, experts remain concerned about the lack of regulation of herbs/supplements and the need for further research on potential adverse effects and herb–drug interactions. In conclusion, preliminary data on several herbs have demonstrated promising antioxidant, anti-inflammatory, anti-apoptotic, and anti-adipogenic properties that may help curtail the progression of NAFLD/NASH. Clinical trials testing the safety and efficacy must be completed before widespread use can be recommended.

Efficacy of curcumin/turmeric on liver enzymes in patients with non-alcoholic fatty liver disease: A systematic review of randomized controlled trials

Background

Several studies reported that curcumin supplementation could improve non-alcoholic fatty liver disease (NAFLD). The aim of this study was to evaluate the efficacy of curcumin/turmeric supplementation on liver enzymes in patients with NAFLD.

Methods

PubMed, Scopus, Web of Science and Google Scholar were systematically searched until December 2017. We included randomized controlled trials (RCTs) which examined effect of curcumin/turmeric supplementation on NAFLD in adult participants. Main outcome was alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Potential risks of bias (ROB) were assessed by using Cochrane ROB tool.

Results

All included studies showed low ROB in most of item of Cochrane ROB tool. Meta-analysis of 4 randomized controlled trials including 228 subjects showed a trend toward significant reduction of ALT blood concentrations in subgroup with ≥1000 mg/day curcumin supplementation (–11.36 IU/L, 95% CI: –22.75 to 0.02; I²:51%). Meta-analysis showed a significant reduction of AST in studies with 8-weeks administration (–9.22 IU/L, 95% CI: –12.77 to –5.67; I²: 49%).

Conclusion

This review suggests that curcumin/turmeric might have a favorable effect on NAFLD in higher dosage. Further high-quality studies with large-scale and higher dosage are warranted.

Obesity, Fat Mass and Immune System: Role for Leptin

Obesity is an epidemic disease characterized by chronic low-grade inflammation associated with a dysfunctional fat mass. Adipose tissue is now considered an extremely active endocrine organ that secretes cytokine-like hormones, called adipokines, either pro- or anti-inflammatory factors bridging metabolism to the immune system. Leptin is historically one of most relevant adipokines, with important physiological roles in the central control of energy metabolism and in the regulation of metabolism-immune system interplay, being a cornerstone of the emerging field of immunometabolism. Indeed, leptin receptor is expressed throughout the immune system and leptin has been shown to regulate both innate and adaptive immune responses. This review discusses the latest data regarding the role of leptin as a mediator of immune system and metabolism, with particular emphasis on its effects on obesity-associated metabolic disorders and autoimmune and/or inflammatory rheumatic diseases.

Medicinal plants and bioactive natural compounds in the treatment of non-alcoholic fatty liver disease: A clinical review

Non-alcoholic fatty liver disease (NAFLD) is a major cause of liver diseases, and is closely related to metabolic syndrome and its related conditions, diabetes mellitus and dyslipidemia. On the other hand, NAFLD as a multisystem disease increases the risk of several chronic diseases include type 2 diabetes mellitus, cardiovascular disease (CVD), and chronic kidney disease. The main objective was to review the efficacy of bioactive natural compounds assessed by clinical trials. Search literature using four databases (PubMed, EBSCO, Web of Science, and Ovid Medline) to review publications that focused on the impact of bioactive natural compounds in NAFLD treatment. Due to the lack of effective pharmacological treatments available for NAFLD, lifestyle modifications such as following a healthy diet, vigorous physical activity, and weight reduction remain the first line of treatment for NAFLD. However, due to the poor adherence to this type of treatment, especially for long-term weight loss diets some of which may have harmful effects on the liver, finding novel therapeutic agents for NAFLD treatment and/or preventing NAFLD progression has garnered significant interest. Although the therapeutic agents of NAFLD treatment have been reviewed previously, to date, no summary has been conducted of clinical trials examining the effects of herbal compounds on NAFLD-related biomarkers. This review highlights the beneficial role of herbal bioactives and medicinal plants in NAFLD treatment, particularly as complementary to a healthy lifestyle. All natural products described in this review seem to have some benefits to improve oxidative stress, cellular inflammation and insulin-resistance, which always remain as the "primum movens" of NAFLD pathogenesis.

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.

Non-Alcoholic Fatty Liver Disease and Nutritional Implications: Special Focus on Copper

Non-alcoholic fatty liver disease (NAFLD) is characterized by excess lipids in hepatocytes, due to excessive fatty acid influx from adipose tissue, de novo hepatic lipogenesis, in addition to excessive dietary fat and carbohydrate intake. Chronic hepatic lipid overload induces mitochondrial oxidative stress and cellular damage leading the development of NAFLD into a more severe liver disease condition, non-alcoholic steato-hepatitis (NASH). In turn, this can progress to cirrhosis and hepatocellular carcinoma (HCC). Among others, copper is one of the main bio-metals required for the preponderance of the enzymes involved in physiological redox reactions, which primarily occurs during mitochondrial respiration. Thus, copper homeostasis could be considered a target point for counteracting the progression of NAFLD. Accordingly, many diseases are correlated to unbalanced copper levels and, actually, some clinical trials are examining the use of copper chelating agents. Currently, no pharmacological interventions are approved for NAFLD, but nutritional and lifestyle modifications are always recommended. Fittingly, antioxidant food agents recognized to improve NAFLD and its complications have been described in the literature to bind copper. Therefore, this review describes the role of nutrition in the development and progression of NAFLD with a particular focus on copper and copper-binding antioxidant compounds against NAFLD.