System Biology Investigation Revealed Lipopolysaccharide and Alcohol-Induced Hepatocellular Carcinoma Resembled Hepatitis B Virus Immunobiology and Pathogenesis

Hepatitis B infection caused by the hepatitis B virus is a life-threatening cause of liver fibrosis, cirrhosis, and hepatocellular carcinoma. Researchers have produced multiple in vivo models for hepatitis B virus (HBV) and, currently, there are no specific laboratory animal models available to study HBV pathogenesis or immune response; nonetheless, their limitations prevent them from being used to study HBV pathogenesis, immune response, or therapeutic methods because HBV can only infect humans and chimpanzees. The current study is the first of its kind to identify a suitable chemically induced liver cirrhosis/HCC model that parallels HBV pathophysiology. Initially, data from the peer-reviewed literature and the GeneCards database were compiled to identify the genes that HBV and seven drugs (acetaminophen, isoniazid, alcohol, D-galactosamine, lipopolysaccharide, thioacetamide, and rifampicin) regulate. Functional enrichment analysis was performed in the STRING server. The network HBV/Chemical, genes, and pathways were constructed by Cytoscape 3.6.1. About 1546 genes were modulated by HBV, of which 25.2% and 17.6% of the genes were common for alcohol and lipopolysaccharide-induced hepatitis. In accordance with the enrichment analysis, HBV activates the signaling pathways for apoptosis, cell cycle, PI3K-Akt, TNF, JAK-STAT, MAPK, chemokines, NF-kappa B, and TGF-beta. In addition, alcohol and lipopolysaccharide significantly activated these pathways more than other chemicals, with higher gene counts and lower FDR scores. In conclusion, alcohol-induced hepatitis could be a suitable model to study chronic HBV infection and lipopolysaccharide-induced hepatitis for an acute inflammatory response to HBV.

A review of edible plant-derived natural compounds for the therapy of liver fibrosis

Liver fibrosis has a high incidence worldwide and is the common pathological basis of many chronic liver diseases. Liver fibrosis is caused by the excessive deposition of extracellular matrix and concomitant collagen accumulation in livers and can lead to the development of liver cirrhosis and even liver cancer. A large number of studies have provided evidence that liver fibrosis can be blocked or even reversed by appropriate medical interventions. However, the antifibrosis drugs with ideal clinical efficacy are still insufficient. The edible plant-derived natural compounds have been reported to exert effective antifibrotic effects with few side-effects, representing a kind of promising source for the treatment of liver fibrosis. In this article, we reviewed the current progress of the natural compounds derived from dietary plants in the treatment of liver fibrosis, including phenolic compounds (capsaicin, chlorogenic acid, curcumin, ellagic acid, epigallocatechin-3-gallate, resveratrol, sinapic acid, syringic acid, vanillic acid and vitamin E), flavonoid compounds (genistein, hesperidin, hesperetin, naringenin, naringin and quercetin), sulfur-containing compounds (S-allylcysteine, ergothioneine, lipoic acid and sulforaphane) and other compounds (betaine, caffeine, cucurbitacin B, lycopene, α-mangostin, γ-mangostin, ursolic acid, vitamin C and yangonin). The pharmacological effects and related mechanisms of these compounds in in-vivo and in-vitro models of liver fibrosis are focused.

Renoprotective Roles of Curcumin

The use of herb-based therapies is increasing over the past decades. These agents have been reported to provide many beneficial effects in many experimental and clinical studies. Curcumin is one of these agents which has potent pharmacological effects enabling it for the prevent and treatment of many diseases and pathologies such as renal disorders, hyperglycemia, oxidative stress, hypertension, and dyslipidemia. However, the exact molecular mechanisms mediating these renoprotective effects of curcumin are not well established. So, in the current study, we surveyed for possible renoprotective roles of curcumin and concluded how curcumin protects against renal injuries.

Taurine as a Natural Antioxidant: From Direct Antioxidant Effects to Protective Action in Various Toxicological Models

Natural antioxidants have received tremendous attention over the last 3 decades. At the same time, the attitude to free radicals is slowly changing, and their signalling role in adaptation to stress has recently received a lot of attention. Among many different antioxidants in the body, taurine (Tau), a sulphur-containing non-proteinogenic β-amino acid, is shown to have a special place as an important natural modulator of the antioxidant defence networks. Indeed, Tau is synthesised in most mammals and birds, and the Tau requirement is met by both synthesis and food/feed supply. From the analysis of recent data, it could be concluded that the direct antioxidant effect of Tau due to scavenging free radicals is limited and could be expected only in a few mammalian/avian tissues (e.g., heart and eye) with comparatively high (>15-20 mM) Tau concentrations. The stabilising effects of Tau on mitochondria, a prime site of free radical formation, are characterised and deserve more attention. Tau deficiency has been shown to compromise the electron transport chain in mitochondria and significantly increase free radical production. It seems likely that by maintaining the optimal Tau status of mitochondria, it is possible to control free radical production. Tau's antioxidant protective action is of great importance in various stress conditions in human life, and is related to commercial animal and poultry production. In various in vitro and in vivo toxicological models, Tau showed AO protective effects. The membrane-stabilizing effects, inhibiting effects on ROS-producing enzymes, as well as the indirect AO effects of Tau via redox balance maintenance associated with the modulation of various transcription factors (e.g., Nrf2 and NF-κB) and vitagenes could also contribute to its protective action in stress conditions, and thus deserve more attention.

Catechin and curcumin interact with S protein of SARS-CoV2 and ACE2 of human cell membrane: insights from computational studies

The recent outbreak of the coronavirus (SARS-CoV2) is an unprecedented threat to human health and society across the globe. In this context, development of suitable interventions is the need of the hour. The viral spike protein (S Protein) and the cognate host cell receptor ACE2 can be considered as effective and appropriate targets for interventions. It is evident from the present computational study, that catechin and curcumin, not only exhibit strong binding affinity to viral S Protein and host receptor ACE2 but also to their complex (receptor-binding domain (RBD) of the spike protein of SARS-CoV2 and ACE2; RBD/ACE2-complex). The binding affinity values of catechin and curcumin for the S protein, ACE2 and RBD/ACE2-complex are − 10.5 and − 7.9 kcal/mol; − 8.9 and − 7.8 kcal/mol; and − 9.1 and − 7.6 kcal/mol, respectively. Curcumin directly binds to the receptor binding domain (RBD) of viral S Protein. Molecular simulation study over a period of 100 ns further substantiates that such interaction within RBD site of S Protein occurs during 40–100 ns out of 100 ns simulation trajectory. Contrary to this, catechin binds with amino acid residues present near the RBD site of S Protein and causes fluctuation in the amino acid residues of the RBD and its near proximity. Both catechin and curcumin bind the interface of ‘RBD/ACE2-complex’ and intervene in causing fluctuation of the alpha helices and beta-strands of the protein complex. Protein–protein interaction studies in presence of curcumin or catechin also corroborate the above findings suggesting the efficacy of these two polyphenols in hindering the formation of S Protein-ACE2 complex. In conclusion, this computational study for the first time predicts the possibility of above two polyphenols for therapeutic strategy against SARS-CoV2.

Effects of Phytochemicals on Blood Pressure and Neuroprotection Mediated Via Brain Renin-Angiotensin System

Background: The renin-angiotensin system (RAS) in the brain plays a crucial role in maintaining blood pressure as well as neuroprotection. This study compared the effects of curcumin, quercetin, and saponin on blood pressure, the brain RAS, and cholinergic system using perindopril, an angiotensin converting enzyme inhibitor (ACEI), as a positive control. Methods: Five-week-old male mice were stabilized and randomly assigned into a control group (n = 8), three phytochemical-treated groups (curcumin (n = 8), quercetin (n = 8), and saponin (n = 8)), and a positive control group (n = 8). The groups treated with the phytochemical were orally administered daily at a dose of 50 mg/kg body weight of phytochemicals. During the experiments, the weight and dietary intakes were measured regularly. After experiments, the brain tissue was homogenized and centrifuged for an additional assay. The concentrations of ACE, angiotensin II (AngII), and aldosterone levels were measured, and the mRNA expressions of renin and ACE were measured. As biomarkers of neuroprotection, the concentrations of acetylcholine (ACh) as well as the concentration and activity of acetylcholine esterase (AChE) were measured. Results: After 4 weeks of treatment, the perindopril group showed the lowest blood pressure. Among the groups treated with the phytochemicals, treatment with curcumin and saponin significantly reduced blood pressure, although such effect was not as high as that of perindopril. Among phytochemicals, curcumin treatment significantly inhibited the concentration and activity of ACE, concentration of AngII, and mRNA expression of ACE. All phytochemical treatments significantly increased the concentration of ACh. The levels of AChE activity in groups exposed to curcumin or saponin (not quercetin) were significantly inhibited, Conclusion: Curcumin administration in rats reduced blood pressure by blocking the brain RAS components and protected the cholinergic system in brain by inhibiting the activity of AChE.

Protective effect of Moringa oleifera leaves ethanolic extract against thioacetamide-induced hepatotoxicity in rats via modulation of cellular antioxidant, apoptotic and inflammatory markers

The current study was conducted to evaluate the ameliorative and protective potentials of Moringea oleifera leaves ethanolic extract (MOLE) against thioacetamide (TAA) toxicity. A total of 58 male albino rats were randomly assigned into six experimental groups. G1, rats received distilled water. G2, rats were injected with a single dose of TAA (200 mg/kg BW) i.p. G3, rats were given MOLE (300 mg/kg BW) orally for 26 days. G4, rats were injected TAA as in G2 and treated with MOLE as G3. G5, rats were kept for 26 days without treatment then on day 27 injected with TAA as in G2. G6, rats were given MOLE for 26 days then on day 27 injected with TAA. Phytochemical analysis of MOLE indicated the presence of kaempferol, kaempferol malonylglucoside, kaempferol hexoside, kaempferol -3-O-glucoside, kaempferol-3-O-acetyl-glucoside, cyanidin -3-O-hexoside, ellagic acid, quercetin, quercetin-3-O-glucoside, and apigenin glucoside. Intoxication of rats with TAA significantly elevated activities of serum AST, ALT, and ALP; concentrations of malondialdehyde, nitric oxide, and hepatic tissue protein expression of caspase 3 and COX2 with alteration of the histological structures of hepatic tissues, while it decreased serum levels of total protein, albumin, and hepatic tissue contents of reduced glutathione. Also, TAA intoxication resulted in 62.5% mortality in rats of G5. Treatment of TAA intoxicated rats (G4) with MOLE ameliorated the toxic effects of TAA on hepatic tissue structure and function. It decreased serum activities of AST, ALT, and ALP; enhanced hepatic GSH concentration; reduced pathological alterations and lipid peroxidation; and downregulated caspase 3 and COX2 proteins expression in hepatic tissue. In addition, MOLE protected rats of G6 from TAA-induced hepatic tissues injury and dysfunction, and increased survival rate of rats. In conclusion, MOLE had both ameliorating and protecting potentials against TAA-induced rats liver damage through regulation of antioxidant, anti-apoptotic, and inflammatory biomarkers. Graphical abstract.

Curcumin inhibits high glucose‑induced inflammatory injury in human retinal pigment epithelial cells through the ROS‑PI3K/AKT/mTOR signaling pathway

Diabetic retinopathy (DR) is a retinal disease caused by metabolic disorders of glucose tolerance that can lead to irreversible blindness if not adequately treated. Retinal pigment epithelial cell (RPEC) dysfunction contributes to the pathogenesis of DR. In the present study the anti‑inflammatory effect of curcumin (CUR) was investigated in RPECs damaged by high glucose levels. RPEC treated with 30 mmol/l glucose was regarded as high glucose group, and cells treated with 24.4 mmol/l mannitol was set as equivalent osmolarity group. Cell Counting Kit‑8 assay was used to measure RPEC viability, the expression of phosphorylated (p)‑AKT and p‑mammalian target of rapamycin (mTOR) were assessed by western blot, and secretion of tumor necrosis factor (TNF)‑α, interleukin (IL)‑6 and IL‑1β in the culture medium was measured by ELISA. Intracellular reactive oxygen species (ROS) levels were measured by laser scanning confocal microscope. The present data indicated that, compared with mannitol treatment, high glucose treatment reduced RPEC viability, increased TNF‑α, IL‑6 and IL‑1β secretion, increased ROS formation and promoted phosphorylation of AKT and mTOR. The antioxidant N‑acetylcysteine, the phosphoinositide 3‑kinase (PI3K)/AKT inhibitor LY294002 and the mTOR inhibitor rapamycin ameliorated the effects of high glucose. In addition, pretreatment with 10 µmol/l CUR reduced secretion levels of TNF‑α, IL‑6 and IL‑1β, ROS formation and phosphorylation of AKT and mTOR. In conclusion, CUR inhibited high glucose‑induced inflammatory injury in RPECs by interfering with the ROS/PI3K/AKT/mTOR signaling pathway. The present study may reveal the molecular mechanism of CUR inhibition effects to high glucose‑induced inflammatory injury in RPEC.

Curcumin in Liver Diseases: A Systematic Review of the Cellular Mechanisms of Oxidative Stress and Clinical Perspective

Oxidative stress has been considered a key causing factor of liver damage induced by a variety of agents, including alcohol, drugs, viral infections, environmental pollutants and dietary components, which in turn results in progression of liver injury, non-alcoholic steatohepatitis, non-alcoholic liver disease, liver fibrosis and cirrhosis. During the past 30 years and even after the major progress in the liver disease management, millions of people worldwide still suffer from an acute or chronic liver condition. Curcumin is one of the most commonly used indigenous molecules endowed by various shielding functionalities that protects the liver. The aim of the present study is to comprehensively review pharmacological effects and molecular mechanisms, as well as clinical evidence, of curcumin as a lead compound in the prevention and treatment of oxidative associated liver diseases. For this purpose, electronic databases including “Scopus,” “PubMed,” “Science Direct” and “Cochrane library” were extensively searched with the keywords “curcumin or curcuminoids” and “hepatoprotective or hepatotoxicity or liver” along with “oxidative or oxidant.” Results showed that curcumin exerts remarkable protective and therapeutic effects of oxidative associated liver diseases through various cellular and molecular mechanisms. Those mechanisms include suppressing the proinflammatory cytokines, lipid perodixation products, PI3K/Akt and hepatic stellate cells activation, as well as ameliorating cellular responses to oxidative stress such as the expression of Nrf2, SOD, CAT, GSH, GPx and GR. Taking together, curcumin itself acts as a free radical scavenger over the activity of different kinds of ROS via its phenolic, β-diketone and methoxy group. Further clinical studies are still needed in order to recognize the structure-activity relationships and molecular mechanisms of curcumin in oxidative associated liver diseases.

Curcumin attenuates high glucose-induced inflammatory injury through the reactive oxygen species-phosphoinositide 3-kinase/protein kinase B-nuclear factor-κB signaling pathway in rat thoracic aorta endothelial cells

AIMS/INTRODUCTION

Endothelial cell inflammatory injury is likely required for barrier dysfunction under hyperglycemic conditions. Curcumin (CUR) is well known for its anti-inflammatory effect. However, there have been few reports about the anti-inflammatory effect of CUR induced by high glucose in endothelial cells. The aim of the present study was to investigate the inflammatory effect of high glucose and the anti-inflammatory effect of CUR induced by high glucose in rat thoracic aorta endothelial cells (TAECs).

MATERIALS AND METHODS

Well characterized TAECs were established and cell viability was assayed by the cell counting kit-8 method, messenger ribonucleic acid and protein expression were identified by real-time polymerase chain reaction, western blot or enzyme-linked immunosorbent assay, respectively. The production of reactive oxygen species was observed by a fluorescence microscope.

RESULTS

High glucose (30 mmol/L) significantly decreased the cell viability of TAECs after being co-cultivated for 12 h and showed a time-dependent manner, and increased interleukin (IL)-1β, IL-6 and tumor necrosis factor-α secretion in TAECs. The injury effect of high glucose was involved in the reactive oxygen species-phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)-nuclear factor (NF)-κB signaling pathway. Anti-oxidant N-acetylcysteine, PI3K and NF-κB-specific pathway inhibitors can abolish the secretion of these inflammatory factors; pretreatment with anti-oxidant N-acetylcysteine significantly decreased PI3K expression, the level of phosphorylated AKT and nuclear NF-κB; pretreatment of LY294002 can significantly decrease the NF-κB level in nuclei. After treatment with CUR for 12 h, IL-1β, IL-6 and tumor necrosis factor-α secretion were markedly decreased, and PI3K expression, the phosphorylation of AKT and nuclear NF-κB level were also decreased.

CONCLUSION

Curcumin attenuates high glucose-induced inflammatory injury through the reactive oxygen species-PI3K/AKT-NF-κB signaling pathway in rat thoracic aorta endothelial cells.

Silymarin as a Natural Antioxidant: An Overview of the Current Evidence and Perspectives

Silymarin (SM), an extract from the Silybum marianum (milk thistle) plant containing various flavonolignans (with silybin being the major one), has received a tremendous amount of attention over the last decade as a herbal remedy for liver treatment. In many cases, the antioxidant properties of SM are considered to be responsible for its protective actions. Possible antioxidant mechanisms of SM are evaluated in this review. (1) Direct scavenging free radicals and chelating free Fe and Cu are mainly effective in the gut. (2) Preventing free radical formation by inhibiting specific ROS-producing enzymes, or improving an integrity of mitochondria in stress conditions, are of great importance. (3) Maintaining an optimal redox balance in the cell by activating a range of antioxidant enzymes and non-enzymatic antioxidants, mainly via Nrf2 activation is probably the main driving force of antioxidant (AO)  action of SM. (4) Decreasing inflammatory responses by inhibiting NF-κB pathways is an emerging mechanism of SM protective effects in liver toxicity and various liver diseases. (5) Activating vitagenes, responsible for synthesis of protective molecules, including heat shock proteins (HSPs), thioredoxin and sirtuins and providing additional protection in stress conditions deserves more attention. (6) Affecting the microenvironment of the gut, including SM-bacteria interactions, awaits future investigations. (7) In animal nutrition and disease prevention strategy, SM alone, or in combination with other hepatho-active compounds (carnitine, betaine, vitamin B₁₂, etc.), might have similar hepatoprotective effects as described in human nutrition.