Curcumin protects against acetaminophen-induced apoptosis in hepatic injury

Curcumin: A Potential Detoxifier Against Chemical and Natural Toxicants

The human body gets exposed to a variety of toxins intentionally or unintentionally on a regular basis from sources such as air, water, food, and soil. Certain toxins can be synthetic, while some are biological. The toxins affect the various parts of the body by activating numerous pro-inflammatory markers, like oxidative stresses, that tend to disturb the normal function of the organs ultimately. Nowadays, people use different types of herbal treatments, viz., herbal drinks that contain different spices for detoxification of their bodies. One such example is turmeric, the most commonly available spice in the kitchen and used across all kinds of households. Turmeric contains curcumin, which is a natural polyphenol. Curcumin is a medicinal compound with different biological activities, such as antioxidant, antineoplastic, anti-inflammatory, and antibacterial. Hence, this review gives a comprehensive insight into the promising potential of curcumin in the detoxification of heavy metals, carbon tetrachloride, drugs, alcohol, acrylamide, mycotoxins, nicotine, and plastics. The review encompasses diverse animal-based studies portraying curcumin's role in nullifying the different toxic effects in various organs of the body (especially the liver, kidney, testicles, and brain) by enhancing defensive signaling pathways, improving antioxidant enzyme levels, inhibiting pro-inflammatory markers activities and so on. Furthermore, this review also argues over curcumin's safety assessment for its utilization as a detoxifying agent.

The potential of curcumin in mitigating acetaminophen-induced liver damage

Acetaminophen (APAP) is a widely used over-the-counter medication for pain and fever, but its overuse can lead to liver toxicity, hepatocyte apoptosis, and necrosis. Despite therapeutic advances in drug-induced hepatotoxicity, APAP-induced liver damage still poses a medical challenge. Recently, natural products have emerged as potential options for mitigating the effects of APAP hepatotoxicity. Curcumin, a natural compound with antioxidant and anti-inflammatory properties, has shown promising results in drug-induced hepatotoxicity. However, further investigations are needed to assess the clinical benefits of curcumin. In this review, we discuss the mechanisms of APAP-induced liver damage and the role of curcumin in preventing liver necrosis, oxidative stress, inflammation, and apoptosis caused by APAP overdose. Through its ability to scavenge free radicals, prevent lipid peroxidation, restore glutathione (GSH) levels, and inhibit apoptosis, curcumin has been found to significantly reduce oxidative stress and protect liver tissue from APAP toxicity in various studies. This paper also reviews the potential of novel nanoformulations to enhance the bioavailability of curcumin for improved therapeutic outcomes. Overall, the evidence suggests that curcumin could be a promising intervention to mitigate the harmful effects of APAP overdose and improve liver health. However, further research is required to assess the optimal dosing and timing of curcumin administration in APAP toxicity.

Nephrotoxic effect of cypermethrin ameliorated by nanocurcumin through antioxidative mechanism

Cypermethrin is a pyrethroid showing nephrotoxicity by generating ROS-impaired oxidative stress and changes in inflammatory and apoptotic markers. The harmful consequences are intended to be mitigated by the imbalance between oxidants and antioxidants. The anti-inflammatory and antioxidant possessions of nanocurcumin (NC) with improved bioavailability ameliorate Cyp toxicity in rat kidneys. In our study, Group I was the control while Group II was treated alone with NC (5 mg). Group III was given 50 mg/kg of Cyp for two weeks. Groups IV, V, and VI received Cyp as in group III and co-treatment with varying NC doses after 5 days of Cyp dosing, respectively. All treatments were given orally for two weeks. After the termination of the study, LPO, 4-HNE, GSH, antioxidant catalase, and SOD were evaluated as markers of inflammation and apoptosis along with ELISA, qRT-PCR, and histopathology were used to assess morphological changes. Our work has shown that Cyp causes nephrotoxicity by altering all parameters. The Cyp-treated group was shown to have higher expression of the oxidative stress marker LPO and inflammatory interleukins as well as Bax, NF-kB, caspase-3, and caspase-9. Although LPO, inflammation, and apoptosis are reduced, antioxidant status is improved by NC.

Defining the mechanisms behind the hepatoprotective properties of curcumin

As a critical cause of human dysfunctionality, hepatic failure leads to approximately two million deaths per year and is on the rise. Considering multiple inflammatory, oxidative, and apoptotic mechanisms behind hepatotoxicity, it urges the need for finding novel multi-targeting agents. Curcumin is a phenolic compound with anti-inflammatory, antioxidant, and anti-apoptotic roles. Curcumin possesses auspicious health benefits and protects against several diseases with exceptional safety and tolerability. This review focused on the hepatoprotective mechanisms of curcumin. The need to develop novel delivery systems of curcumin (e.g., nanoparticles, self-micro emulsifying, lipid-based colloids, solid lipid nanoparticles, cyclodextrin inclusion, phospholipid complexes, and nanoemulsions) is also considered.

Effects of gossypin on acetaminophen-induced hepatotoxicity in mice

Liver injury from paracetamol (acetaminophen) (APAP) is common worldwide. To prevent intoxication with a drug with high poisoning, treatment can be made possible with an easily accessible and harmless substance. This study aimed to investigate the hepatoprotective ef-fects of Gossypin (GOS) in mice exposed to an overdose of APAP -the possible mechanism of action. Specifically, serum [alanine aminotransferase (ALT), aspartate transaminase (AST), and hepatic biochemical parameters (glutathione (GSH), malondialdehyde (MDA) and super-oxide dismutase (SOD)] were evaluated. Protein and mRNA levels of inflammatory, apoptot-ic, and cytochrome factors, including TNF-α, IL-1β, IL-6, NF-kB, and CYP2E1, were ana-lyzed using real-time PCR. Pretreatment with GOS significantly reduced APAP-induced he-patic injury via oxidative stress. Along with potent antioxidant activity, GOS promoted APAP hepatic detoxification by regulating AST, ALT, GSH, MDA, and SOD activities and mRNA levels of the cytochrome CYP2E1 gene. The anti-inflammatory activity of GOS in-creases its production. TNF-α, IL-1β and IL-6, through possible NF-kB blockade, are also responsible for its hepatoprotective effect. Taken together, GOS has the potential to be devel-oped as a preventive agent to be administered to patients suffering from APAP overdose.

Drug-induced liver injury and anti-hepatotoxic effect of herbal compounds: a metabolic mechanism perspective

BACKGROUND

Drug-induced liver injury (DILI) is the most challenging and thought-provoking liver problem for hepatologists owing to unregulated medication usage in medical practices, nutritional supplements, and botanicals. Due to underreporting, analysis, and identification issues, clinically evaluated medication hepatotoxicity is prevalent yet hard to quantify.

PURPOSE

This review's primary objective is to thoroughly compare pharmaceutical drugs and herbal compounds that have undergone clinical trials, focusing on their metabolic mechanisms contributing to the onset of liver illnesses and their hepatoprotective effects.

METHODS

The data was gathered from several online sources, such as PubMed, Scopus, Google Scholar, and Web of Science, using appropriate keywords.

RESULTS

The prevalence of conventional and herbal medicine is rising. A comprehensive understanding of the metabolic mechanism is necessary to mitigate the hepatotoxicity induced by drugs and facilitate the incorporation or substitution of herbal medicine instead of pharmaceuticals. Moreover, pre-clinical pharmacological research has the potential to facilitate the development of natural products as therapeutic agents, displaying promising possibilities for their eventual clinical implementation.

CONCLUSIONS

Acetaminophen, isoniazid, rifampicin, diclofenac, and pyrogallol have been identified as the most often reported synthetic drugs that produce hepatotoxicity by oxidative stress, inflammation, apoptosis, and fibrosis during the last several decades. Due to their ability to downregulate many factors (such as cytokines) and activate several enzyme/enzyme systems, herbal substances (such as Gingko biloba extract, curcumin, resveratrol, and silymarin) provide superior protection against harmful mechanisms which induce hepatotoxicity with fewer adverse effects than their synthetic counterparts.

Antinociceptive and anti-inflammatory actions of curcumin and nano curcumin: a comparative study

Background and purpose

Pain and inflammation can be treated by various therapies that for the most part are not effective and can result in adverse effects. The current study was proposed to compare the antinociceptive and anti-inflammatory actions of curcumin and nano curcumin in rats.

Experimental approach

Rats were randomly allocated into ten groups of six for formalin and tail-flick tests including the control group, curcumin and nano curcumin groups (20, 50, 100 mg/kg), morphine group (10 mg/kg), naloxone + 100 mg/kg curcumin group, and naloxone + 100 mg/kg nano curcumin group. There were nine groups for the carrageenan test. Groups 1-7 were the same as the previous division; groups 8 and 9 received 10 mg/kg diclofenac and 1% carrageenan, respectively.

Findings/Results

All doses of nano curcumin significantly decreased the paw-licking time in both phases of the formalin test. In the tail-flick test, curcumin 100, nano curcumin 100, naloxone + curcumin 100, and naloxone + nano curcumin 100 showed significant analgesic effects compared to the control group. In the paw edema test, at 180 s after injection, curcumin (50 and 100 mg/kg) and all doses of nano curcumin significantly inhibited carrageenan-induced edema. Myeloperoxidase activity and lipid peroxidation decreased at doses of 50 and 100 mg/kg of curcumin but at three doses of nano curcumin (20, 50, and 100 mg/kg).

Conclusion and implication

In conclusion, our results suggest that the nanoemulsion formulation of curcumin can be efficient in reducing pain and especially inflammation in lower doses compared to the native form of curcumin.

Natural Products for Acetaminophen-Induced Acute Liver Injury: A Review

The liver plays a vital role in metabolism, synthesis, and detoxification, but it is susceptible to damage from various factors such as viral infections, drug reactions, excessive alcohol consumption, and autoimmune diseases. This susceptibility is particularly problematic for patients requiring medication, as drug-induced liver injury often leads to underestimation, misdiagnosis, and difficulties in treatment. Acetaminophen (APAP) is a widely used and safe drug in therapeutic doses but can cause liver toxicity when taken in excessive amounts. This study aimed to investigate the hepatotoxicity of APAP and explore potential treatment strategies using a mouse model of APAP-induced liver injury. The study involved the evaluation of various natural products for their therapeutic potential. The findings revealed that natural products demonstrated promising hepatoprotective effects, potentially alleviating liver damage and improving liver function through various mechanisms such as oxidative stress and inflammation, which cause changes in signaling pathways. These results underscore the importance of exploring novel treatment options for drug-induced liver injury, suggesting that further research in this area could lead to the development of effective preventive and therapeutic interventions, ultimately benefiting patients with liver injury caused by medicine.

Ethanol Extract of Rosa rugosa Ameliorates Acetaminophen-Induced Liver Injury via Upregulating Sirt1 and Subsequent Potentiation of LKB1/AMPK/Nrf2 Cascade in Hepatocytes

Acetaminophen (APAP)-induced liver injury is a common hepatic disease resulting from drug abuse. Few targeted treatments are available clinically nowadays. The flower bud of Rosa rugosa has a wide range of biological activities. However, it is unclear whether it alleviates liver injury caused by APAP. Here, we prepared an ethanol extract of Rosa rugosa (ERS) and analyzed its chemical profile. Furthermore, we revealed that ERS significantly ameliorated APAP-induced apoptosis and ferroptosis in AML-12 hepatocytes and dampened APAP-mediated cytotoxicity. In AML-12 cells, ERS elevated Sirt1 expression, boosted the LKB1/AMPK/Nrf2 axis, and thereby crippled APAP-induced intracellular oxidative stress. Both EX527 and NAM, which are chemically unrelated inhibitors of Sirt1, blocked ERS-induced activation of LKB1/AMPK/Nrf2 signaling. The protection of ERS against APAP-triggered toxicity in AML-12 cells was subsequently abolished. As expression of LKB1 was knocked down, ERS still upregulated Sirt1 but failed to activate AMPK/Nrf2 cascade or suppress cytotoxicity provoked by APAP. Results of in vivo experiments showed that ERS attenuated APAP-caused hepatocyte apoptosis and ferroptosis and improved liver injury and inflammation. Consistently, ERS boosted Sirt1 expression, increased phosphorylations of LKB1 and AMPK, and promoted Nrf2 nuclear translocation in the livers of APAP-intoxicated mice. Hepatic transcriptions of HO-1 and GCLC, which are downstream antioxidant genes of Nrf2, were also significantly increased in response to ERS. Our results collectively indicated that ERS effectively attenuates APAP-induced liver injury by activating LKB1/AMPK/Nrf2 cascade. Upregulated expression of Sirt1 plays a crucial role in ERS-mediated activation of LKB1.

Involvement of Nrf2, JAK and COX pathways in acetaminophen-induced nephropathy: Role of some antioxidants

Objectives

Acetaminophen (APAP)-induced nephrotoxicity is detrimental consequence for which there has not been a standardized therapeutic regimen. Although, N-acetylcysteine (NAC) is a well-known antidote used in APAP-induced hepatotoxicity, its benefit in nephrotoxicity caused by APAP is almost lacking. This study aimed to compare the possible protective effect of thymoquinone (TQ), curcumin (CR), and α-lipoic acid (α-LA), either in solo or in combination regimens with that of NAC against APAP-induced renal injury.

Design and method

Rats were divided into nine groups; control group, APAP intoxicated group (1000 mg/kg; orally), and the remaining seven groups received, in addition to APAP, oral doses of NAC, TQ, CR, α-LA, CR plus TQ, TQ plus α-LA, or CR plus α-LA. The first dose of the aforementioned antioxidants was given 24 h before APAP, and then the second dose was given 2 h after APAP, whereas the last dose was given 10 h after administration of APAP.

Results

Treatment with APAP elevated kidney markers like serum uric acid, urea, and creatinine. In addition, it increased the serum level of tumor necrosis factor alpha (TNF-α), interleukin-1beta (IL-1β) and thiobarbituric acid reactive species (TBARS). Also, the protein expression of renal janus kinase (JAK) and cyclooxygenase (COX)-2 were all upregulated by APAP. In contrast, the expression of Nrf2 and the renal levels of superoxide dismutase and glutathione were downregulated. Treatment with the indicated natural antioxidants resulted in amelioration of the aberrated parameters through exhibiting anti-inflammatory, antioxidant and free radical-scavenging effects with a variable degree.

Conclusion

The combined administration of CR and TQ exerted the most potent protection against APAP-induced nephrotoxicity through its anti-inflammatory and free radical-scavenging effects (antioxidant) which were comparable to that of NAC-treatment.

The role of curcumin in the liver-gut system diseases: from mechanisms to clinical therapeutic perspective

Natural products have provided abundant sources of lead compounds for new drug discovery and development over the past centuries. Curcumin is a lipophilic polyphenol isolated from turmeric, a plant used in traditional Asian medicine for centuries. Despite the low oral bioavailability, curcumin exhibits profound medicinal value in various diseases, especially liver and gut diseases, bringing an interest in the paradox of its low bioavailability but high bioactivity. Several latest studies suggest that curcumin's health benefits may rely on its positive gastrointestinal effects rather than its poor bioavailability solely. Microbial antigens, metabolites, and bile acids regulate metabolism and immune responses in the intestine and liver, suggesting the possibility that the liver-gut axis bidirectional crosstalk controls gastrointestinal health and diseases. Accordingly, these pieces of evidence have evoked great interest in the curcumin-mediated crosstalk among liver-gut system diseases. The present study discussed the beneficial effects of curcumin against common liver and gut diseases and explored the underlying molecular targets, as well as collected evidence from human clinical studies. Moreover, this study summarized the roles of curcumin in complex metabolic interactions in liver and intestine diseases supporting the application of curcumin in the liver-gut system as a potential therapeutic option, which opens an avenue for clinical use in the future.

Promising hepatoprotective agents from the natural sources: a study of scientific evidence

Background

Natural bioactive components derived from plant secondary metabolites have been pronounced as valuable alternatives for anticipating and subsiding hepatotoxic effects and its chronic complications based on experimental verification. The focus of this review is to elucidate the commonly used modern medicine for the treatment of liver disease and how major phytoconstituents have been tested for hepatoprotective activity, mechanism of action of some promising agents from natural sources, and clinical trial data for treating in patients with different liver diseases by the aid of natural phytoconstituents.

Main text

The review shows fifteen major isolated phytoconstituents, their biological sources, chemical structures, utilized plant parts, type of extracts used, hepatoprotective assay method, and their possible mechanism of action on the hepatoprotection. Nine promising hepatoprotective leads from natural sources with their chemistry and hepatoprotective mechanism are mentioned briefly. The review further includes the recent clinical trial studies of some hepatoprotective leads and their clinical outcome with different liver disease patients. Scientific studies revealed that antioxidant properties are the central mechanism for the phytoconstituents to subside different disease pathways by upsurging antioxidant defense system of cells, scavenging free radicals, down surging lipid peroxidation, improving anti-inflammatory potential, and further protecting the hepatic cell injury. In this review, we summarize recent development of natural product-based hepatoprotective leads and their curative potential for various sort of liver diseases. Furthermore, the usefulness of hit and lead molecules from natural sources for significant clinical benefit to discover new drug molecule and downsizing the problems of medication and chemical-induced hepatotoxic effects is extrapolated.

Conclusion

Further research are encouraged to elucidate the pharmacological principle of these natural-based chemical agents which will stimulate future pharmaceutical development of therapeutically beneficial hepatoprotective regimens.

Acetaminophen-induced liver injury: Molecular mechanism and treatments from natural products

Acetaminophen (APAP) is a widely used analgesic and antipyretic over-the-counter medicine worldwide. Hepatotoxicity caused by APAP overdose is one of the leading causes of acute liver failure (ALF) in the US and in some parts of Europe, limiting its clinical application. Excessive APAP metabolism depletes glutathione and increases N-acetyl-p-benzoquinoneimide (NAPQI) levels, leading to oxidative stress, DNA damage, and cell necrosis in the liver, which in turn leads to liver damage. Studies have shown that natural products such as polyphenols, terpenes, anthraquinones, and sulforaphane can activate the hepatocyte antioxidant defense system with Nrf2 as the core player, reduce oxidative stress damage, and protect the liver. As the key enzyme metabolizing APAP into NAPQI, cytochrome P450 enzymes are also considered to be intriguing target for the treatment of APAP-induced liver injury. Here, we systematically review the hepatoprotective activity and molecular mechanisms of the natural products that are found to counteract the hepatotoxicity caused by APAP, providing reference information for future preclinical and clinical trials of such natural products.

Hepatoprotective Effect of Curcumin Nano-Lipid Carrier against Cypermethrin Toxicity by Countering the Oxidative, Inflammatory, and Apoptotic Changes in Wistar Rats

This study investigated the potential hepatoprotective activity of curcumin-incorporated nano-lipid carrier (Cur-NLC) against cypermethrin (Cyp) toxicity in adult Wistar male rats. All animals in groups III, IV, V, and VI were subjected to Cyp (50 mg/kg) toxicity for 15 days. Three different doses of Cur-NLC (1, 2.5, and 5 mg/kg/day) were administered orally for 10 days. The toxic effects were evaluated considering the increases in serum hepatic biomarkers alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total protein and albumin, and lipid peroxidation (LPO), as well as a decrease in antioxidative activity (reduced glutathione (GSH), superoxide dismutase (SOD), and catalase) and the upregulation of inflammatory cytokines (IL-1β, IL-6, and TNF-α). Immunohistochemistry studies of proteins (NF-κB, Apaf-1, 4-HNE, and Bax) showed enhanced expression, and histopathological examination revealed architectural changes in liver cells, indicating liver toxicity in animals. Toxicity was determined by quantitative and qualitative determinations of DNA fragmentation, which show massive apoptosis with Cyp treatment. The administration of Cur-NLC significantly ameliorates all changes caused by Cyp, such as a decrease in the levels of serum liver markers, an increase in antioxidative parameters, a decrease in expression of inflammatory cytokines (IL-1β, IL-6, TNF-α, and NF-κB), and apoptosis (caspases-3, 9, Apaf-1, 4-HNE, and Bax), according to calorimetric and immunohistochemistry studies. The smear-like pattern of DNA is ameliorated similarly to the control at a high dose of Cur-NLC. Furthermore, all histopathological changes were reduced to a level close to the control. In conclusion, Cur-NLC could be a potent nutraceutical that exhibits a hepatoprotective effect against Cyp-induced hepatotoxicity in rats.

The Effect of Curcumin Nanoparticles on Paracetamol-induced Liver Injury in Male Wistar Rats

INTRODUCTION

Curcumin is a naturally occurring compound that has antioxidant properties, acts as a hepatoprotective, and lowers lipid peroxidation. However, curcumin's low solubility and bioavailability are its primary drawbacks and prevent its use as a therapeutic agent. In this study, curcumin nanoparticles will be created using the ultrasonic-assisted extraction method, and their effectiveness against paracetamol-induced changes in ALT, AST, SOD, MDA, and TNF-α will be compared to that of pure curcumin.

PURPOSE

This study aimed to determine the hepatoprotective effect of curcumin nanoparticles in paracetamol- induced rats as a model for liver injury.

METHODS

Thirty-six male Wistar rats, aged 6 to 8 weeks, with a minimum weight of 120 grams, were used in an experimental laboratory investigation with a post-test-only group design. Rats in each group received 100 mg/kgBW pure curcumin, 100 mg/kgBW curcumin nanoparticles, and 50 mg/kgBW curcumin nanoparticles for 7 days before paracetamol induction. On day 8, 300 mg/kgBW of paracetamol was intraperitoneally injected to cause liver damage. One of the groups received NAC as an antidote 10 hours after paracetamol induction. Detection of ALT and AST using a Chemistry Analyzer. ELISA approach for the detection of SOD, MDA, and TNF-α. The Roenigk score was calculated by two examiners after the liver histopathology preparations were stained using the Hematoxylin-Eosin method. Post hoc analyses were performed after the One Way Annova and Kruskal Wallis tests to examine the data.

RESULTS

According to PSA results, the smallest formula that formed curcumin nanoparticles (10.2 nm) was 8 g of curcumin formula mixed with a mixture of Tween 20 4.5 ml, Kolliphor EL 1.5 ml, Propylene Glycol 1.5 ml, and Capryol 90 1 ml for 21 minutes using an ultrasonic process. MDA and TNF-α levels, as well as the liver's histological Roenigk score, were significantly lower in the 100 mg/kgBB pure curcumin group (C100) when compared to the model group (model). The levels of AST, MDA, TNF-α, and the liver histopathology score were significantly lower in the 100 mg/kgBB (NC100) and 50 mg/kgBB (NC50) curcumin nanoparticle groups compared to the model group (model) and pure curcumin group (C100) (p< 0.05).

CONCLUSION

Curcumin nanoparticles showed better hepatoprotective ability than pure curcumin.

The Synergistic Hepatoprotective Activity of Rosemary Essential Oil and Curcumin: The Role of the MEK/ERK Pathway

BACKGROUND

Curcumin is a natural product obtained from the rhizome of Curcuma longa. Rosemary (Rosmarinus officinalis) is a medicinal and aromatic plant that is widely spread in the Mediterranean region. Both Curcumin and rosemary essential oil are natural products of high medicinal and pharmacological significance. The hepatoprotective effect of both natural products is well-established; however, the mechanism of such action is not fully understood. Thus, this study is an attempt to explore the hepatoprotective mechanism of action of these remedies through their effect on MEK and ERK proteins. Furthermore, the effect of rosemary essential oil on the plasma concentration of curcumin has been scrutinized.

MATERIALS AND METHODS

The major constituents of REO were qualitatively and quantitatively determined by GC/MS and GC/FID, respectively. Curcumin and rosemary essential oil were given to mice in a pre-treatment model, followed by induction of liver injury through a high dose of paracetamol. Serum liver enzymes, lipid peroxidation, antioxidant activities, the inflammatory and apoptotic biomarkers, as well as the MEK and ERK portions, were verified. The plasma levels of curcumin were determined in the presence and absence of rosemary essential oil.

RESULTS

The major constituents of REO were 1,8-cineole (51.52%), camphor (10.52%), and α-pinene (8.41%). The results revealed a superior hepatoprotective activity of the combination when compared to each natural product alone, as demonstrated by the lowered liver enzymes, lipid peroxidation, mitigated inflammatory and apoptotic biomarkers, and enhanced antioxidant activities. Furthermore, the combination induced the overexpression of MEK and ERK proteins, providing evidence for the involvement of this cascade in the hepatoprotective activity of such natural products. The administration of rosemary essential oil with curcumin enhanced the curcuminoid plasma level.

CONCLUSION

The co-administration of both curcumin and rosemary essential oil together enhanced both their hepatoprotective activity and the level of curcumin in plasma, indicating a synergistic activity between both natural products.

Steatosis induced by nonylphenol in HepG2 cells and the intervention effect of curcumin

Non-alcoholic fatty liver disease (NAFLD) has increasingly become a serious public health problem. There is growing evidence that nonylphenol (NP) exposure may cause steatosis, but the underlying mechanism is not fully understood. Curcumin (CUR) improves NAFLD-related lipid metabolism disorders and oxidative stress, but its preventive and therapeutic effects on NP-induced steatosis have not been reported. The objective of this investigation was to determine the capability and potential mechanism of NP to induce steatosis in vitro and the intervention of curcumin. HepG2 cells were treated with 0 μM, 20 μM, 30 μM, 40 μM NP for 24 h. Lipid droplets accumulated significantly in HepG2 cells after NP treatment, and the concentration of triglyceride (TG) and total cholesterol (T-CHO) increased significantly. Simultaneously, lipogenesis gene expression was up-regulated significantly, fatty acid oxidation (FAO) gene expression was significantly down-regulated, and reactive oxygen species (ROS) were overproduced. Meanwhile, the expression of p-AMPK/AMPK in the AMPK/mTOR signaling pathway was significantly down-regulated and the expression of p-mTOR/mTOR was markedly up-regulated. However, blocking ROS production with N-acetyl-L-cysteine (NAC) can reverse these phenomena. In addition, our study found that curcumin effectively ameliorated the effects of NP-induced steatosis. Our study indicates that NP can induce steatosis in HepG2 cells, and may be implicated in inhibiting the ROS-dependent AMPK/mTOR pathway, and that curcumin ameliorates the NAFLD-like changes induced by NP in HepG2 cells.

Kaempferol suppresses acetaminophen-induced liver damage by upregulation/activation of SIRT1

CONTEXT

Kaempferol, a flavonoid glycoside, has many hepatoprotective effects in several animals due to its antioxidant potential.

OBJECTIVE

This study evaluated the hepatoprotective effect of kaempferol against acetaminophen (APAP)-induced liver damage and examined whether the protection involved modulation of silent information regulator 1 (SIRT1) signalling.

MATERIALS AND METHODS

Adult male Wistar rats were classified into four groups (n = 8) and treated as follows: control + normal saline (vehicle), control + kaempferol (250 mg/kg), APAP (800 mg/kg, a single dose) and APAP + kaempferol. Kaempferol was administered for the first seven days followed by administration of APAP. The study was ended 24 h after APAP administration.

RESULTS

At the histological level, kaempferol reduced liver damage in APAP-treated rats. It also reduced the hepatic levels of TNF-α (66.3%), IL-6 (38.6%) and protein levels of caspase-3 (88.2%), and attenuated the increase in circulatory serum levels of ALT (47.6%), AST (55.8%) and γ-GT (35.2%) in APAP-treated rats. In both the controls and APAP-treated rats, kaempferol significantly increased the hepatic levels of glutathione (GSH) and superoxide dismutase, suppressed MDA and reactive oxygen species (ROS) levels, increased protein levels of Bcl-2 and downregulated protein levels of Bax and cleaved Bax. Concomitantly, it reduced the expression of CYP2E1, and the activity and protein levels of SIRT1. Consequently, it decreased the acetylation of all SIRT1 targets including PARP1, p53, NF-κB, FOXO-1 and p53 that mediate antioxidant, anti-inflammatory and anti-apoptotic effects.

DISCUSSION AND CONCLUSIONS

This study encourages the use of kaempferol in further clinical trials to treat APAP-induced hepatotoxicity.

Hepatoprotective Plants from Bangladesh: A Biophytochemical Review and Future Prospect

Liver diseases are quite prevalant in many densely populated countries, including Bangladesh. The liver and its hepatocytes are targeted by virus and microbes, as well as by chemical environmental toxicants, causing wide-spread disruption of metabolic fuctions of the human body, leading to death from end-stage liver diseases. The aim of this review is to systematically explore and record the potential of Bangladeshi ethnopharmacological plants to treat liver diseases with focus on their sources, constituents, and therapeutic uses, including mechanisms of actions (MoA). A literature survey was carried out using Pubmed, Google Scholar, ScienceDirect, and Scopus databases with articles reported until July, 2020. A total of 88 Bangladeshi hepatoprotective plants (BHPs) belonging to 47 families were listed in this review, including Euphorbiaceae, Cucurbitaceae, and Compositae families contained 20% of plants, while herbs were the most cited (51%) and leaves were the most consumed parts (23%) as surveyed. The effect of BHPs against different hepatotoxins was observed via upregulation of antioxidant systems and inhibition of lipid peroxidation which subsequently reduced the elevated liver biomarkers. Different active constituents, including phenolics, curcuminoids, cucurbitanes, terpenoids, fatty acids, carotenoids, and polysaccharides, have been reported from these plants. The hepatoameliorative effect of these constituents was mainly involved in the reduction of hepatic oxidative stress and inflammation through activation of Nrf2/HO-1 and inhibition of NF-κB signaling pathways. In summary, BHPs represent a valuable resource for hepatoprotective lead therapeutics which may offer new alternatives to treat liver diseases.

Research progress in use of traditional Chinese medicine monomer for treatment of non-alcoholic fatty liver disease

With the improvement of people's living standards and the change of eating habits, non-alcoholic fatty liver disease (NAFLD) has gradually become one of the most common chronic liver diseases in the world. However, there are no effective drugs for the treatment of NAFLD. Therefore, it is urgent to find safe, efficient, and economical anti-NAFLD drugs. Compared with western medicines that possess fast lipid-lowering effect, traditional Chinese medicines (TCM) have attracted increasing attention for the treatment of NAFLD due to their unique advantages such as multi-targets and multi-channel mechanisms of action. TCM monomers have been proved to treat NAFLD through regulating various pathways, including inflammation, lipid production, insulin sensitivity, mitochondrial dysfunction, autophagy, and intestinal microbiota. In particular, peroxisome proliferator-activated receptor α (PPAR-α), sterol regulatory element-binding protein 1c (SREBP-1c), nuclear transcription factor kappa (NF-κB), phosphoinositide 3-kinase (PI3K), sirtuin1 (SIRT1), AMP-activated protein kinase (AMPK), p53 and nuclear factor erythroid 2-related factor 2 (Nrf2) are considered as important molecular targets for ameliorating NAFLD by TCM monomers. Therefore, by searching PubMed, Web of Science and SciFinder databases, this paper updates and summarizes the experimental and clinical evidence of TCM monomers for the treatment of NAFLD in the past six years (2015-2020), thus providing thoughts and prospects for further exploring the pathogenesis of NAFLD and TCM monomer therapies.

Boldine treatment protects acetaminophen-induced liver inflammation and acute hepatic necrosis in mice

Drug-induced liver injury (DILI) is a frequent cause responsible for acute liver failure (ALF). Acetaminophen (APAP) is a known hepatotoxin predictably causing intrinsic DILI. At high doses, APAP causes acute liver necrosis and responsible for ALF and liver transplant cases in 50% and 20% of patients, respectively, in the United States alone. Oxidative stress and glutathione depletion are implicated in APAP-induced liver necrosis. Boldine, a plant-derived compound is shown to have promising antioxidant potential. Therefore, this study investigates the protective effect of boldine against APAP-induced acute hepatic necrosis in mice. A single toxic dose of APAP (300 mg/kg b.w. p.o.) was administered in overnight-fasted mice to induce acute liver necrosis. Separately, APAP + boldine and APAP + N-acetylcysteine (NAC) simultaneous treatments were also given. Serum transaminases and reduced glutathione, enzymic antioxidants, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and, IL-6 were evaluated in liver tissue. Acute APAP intoxication significantly elevated serum marker enzymes of hepatotoxicity. APAP administration increased lipid peroxidation, TNF-α, IL-1β, and IL-6 protein expressions. The enzymic antioxidants and reduced glutathione levels were decreased in liver tissue of APAP intoxicated mice. Boldine and NAC simultaneous treatments prevented APAP-induced oxidative stress, inflammation, and necrosis. The results of this study suggest the crucial role of boldine to protect against APAP induced hepatotoxicity by virtue of its antioxidant and anti-inflammatory properties.

Effect of fluoxetine on the testes of adult albino rats and the possible protective role of curcumin

Fluoxetine (FLX) is extensively used for the treatment of a diversity of psychiatric disorders, mainly depression. However, it can adversely affect male fertility. This study was done to clarify the changes which take place in the testes after the oral administration of FLX and to evaluate the possible preventative role of curcumin. Seventy-six adult male albino rats were randomly divided into four equal groups. Control group: kept without any treatment. Curcumin group: received daily dose of curcumin (150 mg/kg body weight) through oral gavage for 8 weeks. FLX group. They were given daily dose of FLX (10 mg/kg body weight) given through oral gavage for 8 weeks. FLX and curcumin group. They were given FLX together with curcumin with the same previous doses through oral gavage daily for 8 weeks. By the end of the experiment, blood samples were collected for the biochemical study of testosterone. All the animals were anaesthetized by ether inhalation, and the testis specimens were dissected out and weighed. The specimens were subjected to histopathological, immunohistochemical, and morphometrical evaluation. FLX decreased serum testosterone, diminished both epithelial height and diameter of seminiferous tubules, increased collagen fiber deposition in testicular tissue and induced positive immune reaction to B-cell lymphoma-2-associated X protein. In the FLX and curcumin group, the FLX-induced changes were less remarkable. Exposure to FLX led to pronounced testicular alterations. Co-administration of curcumin with FLX ameliorated these changes.

NIR-II FL/PA dual-modal imaging long-term tracking of human umbilical cord-derived mesenchymal stem cells labeled with melanin nanoparticles and visible HUMSC-based liver regeneration for acute liver failure

Acetaminophen (APAP) has been widely used for relieving pain and fever, whilst overdose would lead to the occurrence of acute liver failure (ALF). Currently, few effective treatments are available for ALF in clinic, especially for severe, advanced- or end-stage patients who need liver transplantation. Human umbilical cord-derived mesenchymal stem cells (hUMSCs), as one of the mesenchymal stem cells, not only contribute to relieving hepatotoxicity and promoting hepatocyte regeneration due to their self-renewing, multi-differentiation potential, anti-inflammatory, immunomodulatory and paracrine properties, but possess lower immunomodulatory effects, faster self-renewal properties and noncontroversial ethical concerns, which may play a better role in the treatment of ALF. In this work, hUMSCs were rapidly labeled with near-infrared II fluorescent dye-modified melanin nanoparticles (MNP-PEG-H2), which could realize long-term tracking of hUMSCs by NIR-II fluorescent (FL)/photoacoustic (PA) dual-modal imaging and could visualize hUMSC-based liver regeneration in ALF. The nanoparticles exhibited good dispersibility and biocompatibility, high labeling efficiency for hUMSCs and excellent NIR-II FL/PA imaging performance. Moreover, the MNP-PEG-H2 labeled hUMSCs could be continuously traced in vivo for up to 21 days. After intravenous delivery, the NIR-II FL and PA images revealed that labeled hUMSCs were able to engraft in the injured liver and repair damaged tissue in ALF mice. Therefore, the hUMSCs labeled with endogenous melanin nanoparticles solve the key tracing problem of MSC-based regenerative medicine and realize the visualization of the treatment process, which may provide an efficient, safe and potential choice for ALF.

Cinnamon oil against acetaminophen-induced acute liver toxicity by attenuating inflammation, oxidative stress and apoptosis

Acetaminophen (APAP) is used as a primary drug due to its antipyretic and analgesic activity. The mechanism of action of APAP toxicity in the liver is due to the depletion of glutathione which elicited free radicals generation. Therefore, the objective of our work is to investigate the APAP induced liver damage and its repair by free radical scavenging activity of cinnamon oil (CO) in male Wistar rats. To investigate the effects of CO at different doses (50, 100 and 200 mg/kg b.w.), animals were given a single oral dose of CO per day for 14 days between 12:00-1:00 PM. The biochemical changes, imbalance in oxidative markers, interleukins, caspases and histopathological studies were determined for quantifying the hepatoprotective effect of CO. One dose of APAP (2 g/kg b.w.) results in significant hepatotoxicity and marked increase the serum markers alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), bilirubin, albumin, total protein, content of lipid peroxidation (LPO), interleukins (IL-1β, IL-6), caspase-3, -9 expression, DNA fragmentation and histopathological changes were observed. Significant decrease in the levels of LPO, interleukins IL-1β, IL-6, caspase-3, -9 expressions, qualitative as well as quantitative determination of DNA fragments and histopathological changes were reversed by the administration of CO dose dependently. Furthermore, it also restores the depleted activity of antioxidative enzymes. Our study shows that an imbalance in the oxidative parameter in the liver by APAP is restored by treating the animals with CO.

Curcumin incorporated titanium dioxide nanoparticles as MRI contrasting agent for early diagnosis of atherosclerosis- rat model

MRI is an excellent diagnostic technique for atherosclerosis in a non-invasive manner. Application of contrasting agents can improve its contrast through ionic properties. Macrophages and foam cells produce MCP-1 antibody, the sign of development of atherosclerosis. The work aims to develop novel curcumin incorporated titanium dioxide nanoparticles (CTNPs) conjugated with MCP-1 antibody with the specific targeting capability to macrophage-foam cells as contrasting agent for MRI. In vivo toxicity studies of Curcumin, TNPs and CTNPs were also done in Sprague dawley rats by GGT and ALP assays and found to be normal in comparison with control. Histopathology of aorta confirmed that the compound could not elicit a toxic effect in the target organ. Rats were fed with a high cholesterol diet to develop atherosclerotic foam cells and confirmed by Sudan IV staining and serum cholesterol level. CTNP-MCP-1 was injected into animals through tail vein and MRI scanning was done, gave contrasting images of atherosclerotic aorta in comparison with normal. Thus CTNPs can be used as a cost-effective contrasting tool for diagnosis of atherosclerosis at early stages in view of clinical imaging.

Probiotic Bacillus Spores Protect Against Acetaminophen Induced Acute Liver Injury in Rats

Acetaminophen (APAP) is one of the most used analgesics and antipyretic agents in the world. Intoxication with APAP is the main cause of acute liver toxicity in both the US and Europe. Spore-forming probiotic bacteria have the ability to resist harsh gastric and intestinal conditions. The aim of this study was to investigate the possible protective effect of Bacillus (B) species (sp) spores (B. licheniformis, B. indicus, B. subtilis, B. clausii, B. coagulans) against hepatotoxicity induced by APAP in rats. A total of 35 rats were randomly divided into seven groups: group I served as control; group II received silymarin; group III received MegaSporeBiotic^TM (MSB); group IV received APAP and served as the model of hepatotoxicity; group V received APAP and silymarin; group VI received APAP and MSB; group VII received APAP, silymarin and MSB. The livers for histopathological examination and blood samples were collected on the last day of the experiment. We determined aspartate aminotransferase (AST), alanine aminotransferase (ALT) and total antioxidant capacity (TAC) levels and zonula occludens (ZO-1), tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β) expression. APAP overdose increased AST and ALT. It slowly decreased TAC compared to the control group, but pretreatment with silymarin and MSB increased TAC levels. Elevated plasma concentrations were identified for ZO-1 in groups treated with APAP overdose compared with those without APAP or receiving APAP in combination with silymarin, MSB or both. The changes were positively correlated with the levels of other proinflammatory cytokines (TNF-α, IL-1β). In addition, histopathological hepatic injury was improved by preadministration of MSB or silymarin versus the disease model group. Bacillus sp spores had a protective effect on acute hepatic injury induced by APAP. Pretreatment with MSB resulted in a significant reduction in serum AST, ALT, TNF-α, IL-1β, ZO-1, TAC and also hepatocyte necrosis, similar to the well-known hepatoprotective agent—silymarin.

FGF1 protects against APAP-induced hepatotoxicity via suppression of oxidative and endoplasmic reticulum stress

Acetaminophen (APAP) overdose/abuse is the leading cause of acute liver failure in many countries. Fibroblast growth factor 1 (FGF 1) is a metabolic regulator with several physiological functions. Previous studies suggested that FGF1 promotes differentiation and maturation of liver-derived stem cells. In this study, we investigated the protective effects of FGF1 against APAP-induced hepatotoxicity in mice. APAP markedly increased circulating levels of ALT and AST, while FGF1 significantly inhibited increases in the serum levels of ALT and AST, as compared to littermates. In addition, histopathological evaluation of the livers revealed that FGF1 prevented APAP-induced centrilobular necrosis. Livers exhibited severe inflammation, apoptosis, oxidative stress and endoplasmic reticulum stress in response to APAP toxicity, whereas these changes were reversed by a single injection of FGF1. In conclusion, our findings suggest that FGF1 protects mice from APAP-induced hepatotoxicity through suppression of inflammation, apoptosis, and oxidative and endoplasmic reticulum stress. Therefore, FGF1 may represent a promising therapeutic agent for APAP-induced acute liver injury.

The protective efficacy of soursop fruit extract against hepatic injury associated with acetaminophen exposure is mediated through antioxidant, anti-inflammatory, and anti-apoptotic activities

In the current report, we examined the potential beneficial role of soursop fruit extract (SSFE) on liver injury induced by a single paracetamol (APAP) overdose (2000 mg/kg). Thirty-five Wistar albino rats were randomly divided into five groups as follows: control, SSFE, APAP, SSFE+APAP, and silymarin (SIL)+APAP. APAP intoxication was found to elevate alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and total bilirubin levels. Moreover, it increased the levels of malondialdehyde, nitrites, and nitrates and depleted glutathione, superoxide dismutase, catalase, glutathione reductase, and glutathione peroxidase. APAP intoxication inactivated the nuclear factor erythroid 2-related factor 2 (Nrf2) defense pathway and upregulated the expression of heme oxygenase-1 (HO-1). APAP administration enhanced the activation of nuclear factor-kappa B (NF-κB), the elevation of tumor necrosis factor-alpha and interleukin 1-beta levels, and the upregulation of inducible nitric oxide synthase mRNA expression. In addition, APAP activated the overexpression of Bax protein, increased release of cytochrome c, and the downregulation of Bcl-2 protein. Finally, APAP-induced overexpression of transforming growth factor-beta (TGF-β) further suggested enhanced liver damage. On the other hand, SSFE pretreatment attenuated these biochemical, molecular, and histopathological alterations in the liver, which might be partially due to the regulation of hepatic Nrf2/HO-1 and downregulation of NF-κB and TGF-β.

Myristica fragrans Kernels Prevent Paracetamol-Induced Hepatotoxicity by Inducing Anti-Apoptotic Genes and Nrf2/HO-1 Pathway

Paracetamol is responsible for acute liver failure in humans and experimental animals when taken at high doses and transformed into a reactive metabolite by the liver cytochrome P450. On the other hand, nutmeg is rich with many phytochemical ingredients that are known for their ability to inhibit cytochrome P450. Hence, the present experiment was aimed at studying the hepatoprotective effect of Myristica fragrans (nutmeg), kernel extract (MFKE) in respect to paracetamol (acetaminophen; N-acetyl-p-amino-phenol (APAP))-induced hepatotoxicity in rats, focusing on its antioxidant, anti-inflammatory, and anti-apoptotic activities. Liver toxicity was induced in rats by a single oral administration of APAP (2 g/kg). To evaluate the hepatoprotective effect of MFKE against this APAP-induced hepatotoxicity, rats were pre-treated with either oral administration of MFKE at 300 mg/kg daily for seven days or silymarin at 50 mg/kg as a standard hepatoprotective agent. APAP intoxication caused a drastic elevation in liver function markers (transaminases, alkaline phosphatase, and total bilirubin), oxidative stress indicators (lipid peroxidation and nitric oxide), inflammatory biomarkers (tumour necrosis factor-α, interleukin-1β, inducible nitric oxide synthase, and nuclear factor ĸB) and the pro-apoptotic BCL2 Associated X (Bax) and caspases-3 genes. Furthermore, analyses of rat liver tissue revealed that APAP significantly depleted glutathione and inhibited the activities of antioxidant enzymes in addition to downregulating two key anti-apoptotic genes: Cellular FLICE (FADD-like IL-1β-converting enzyme)-inhibitory protein (c-FLIP) and B-cell lymphoma 2 (Bcl-2). Pre-treatment with MFKE, however, attenuated APAP-induced liver toxicity by reversing all of these toxicity biomarkers. This hepatoprotective effect of MFKE was further confirmed by improvement in histopathological findings. Interestingly, the hepatoprotective effect of MFKE was comparable to that offered by the reference hepatoprotector, silymarin. In conclusion, our results revealed that MFKE had antioxidant, anti-inflammatory, and anti-apoptotic properties, and it is suggested that this hepatoprotective effect could be linked to its ability to promote the nuclear factor erythroid 2⁻related factor 2 (Nrf2)/antioxidant responsive element (ARE) pathway.

Cell death in drug-induced liver injury

Drug-induced liver injury (DILI) is an important cause of liver toxicity which can have varying clinical presentations, the most severe of which being acute liver failure. Hepatocyte death as a cause of drug toxicity is a feature of DILI. There are multiple cell death subroutines; some, like apoptosis, necroptosis, autophagy, and necrosis have been extensively studied, while others such as pyroptosis and ferroptosis have been more recently described. The mode of cell death in DILI depends on the culprit drug, as it largely dictates the mechanism and extent of injury. The main cell death subroutines in DILI are apoptosis and necrosis, with mitochondrial involvement being pivotal for the execution of both. A few drugs such as acetaminophen (APAP) can cause direct, dose-dependent toxicity, while the majority of drugs cause idiosyncratic DILI (IDILI). IDILI is an unpredictable form of liver injury that is not dose dependent, occurs in individuals with a genetic predisposition, and presents with variable latency. APAP-induced programmed necrosis has been extensively studied. However, the mechanisms and pathogenesis of cell death from drugs causing IDILI are harder to elucidate due to the complex and multifactorial nature of the disease. Cell death in IDILI is likely death receptor-mediated apoptosis and the result of an activated innate and adaptive immune system, compounded by other host factors such as genetics, gender, age, and capacity for immune tolerance. This chapter will review the different modes of cell death, namely apoptosis, necrosis, necroptosis, autophagy, pyroptosis, and ferroptosis and their pertinence to DILI.

Mechanistic insights of hepatoprotective effects of curcumin: Therapeutic updates and future prospects

The liver is the most essential organ of the body performing vital functions. Hepatic disorders affect the physiological and biochemical functions of the body. These disorders include hepatitis B, hepatitis C, alcoholic liver disease (ALD), nonalcoholic fatty liver disease (NAFLD), liver cirrhosis, hepatic failure and hepatocellular carcinoma (HCC). Drugs related hepatotoxicity is one of the major challenges facing by clinicians as it is a leading cause of liver failure. During post-marketing surveillance studies, detection and reporting of drug-induced hepatotoxicity may lead to drug withdrawal or warnings. Several mechanisms are involved in hepatotoxicity such as cell membrane disruption, initiating an immune response, alteration of cellular pathways of drug metabolism, accumulation of reactive oxygen species (ROS), lipid peroxidation and cell death. Curcumin, the active ingredient of turmeric and exhibits therapeutic potential for the treatment of diabetes, cardiovascular disorders and various types of cancers. Curcumin is strong anti-oxidant and anti-inflammatory effects and thus it possesses hepatoprotective properties. Despite its low bioavailability, its hepatoprotective effects have been studied in various protocols of hepatotoxicity including acetaminophen, alcohol, lindane, carbon tetrachloride (CCL4), diethylnitrosamine and heavy metals induced hepatotoxicities. This report reviews the hepatoprotective effects of curcumin with a focus on its mechanistic insights in various hepatotoxic protocols.

Therapeutic Potential of Plants and Plant Derived Phytochemicals against Acetaminophen-Induced Liver Injury

Acetaminophen (APAP), which is also known as paracetamol or N-acetyl-p-aminophenol is a safe and potent drug for fever, pain and inflammation when used at its normal therapeutic doses. It is available as over-the-counter drug and used by all the age groups. The overdose results in acute liver failure that often requires liver transplantation. Current clinical therapy for APAP-induced liver toxicity is the administration of N-acetyl-cysteine (NAC), a sulphydryl compound an approved drug which acts by replenishing cellular glutathione (GSH) stores in the liver. Over the past five decades, several studies indicate that the safety and efficacy of herbal extracts or plant derived compounds that are used either as monotherapy or as an adjunct therapy along with conventional medicines for hepatotoxicity have shown favorable responses. Phytochemicals mitigate necrotic cell death and protect against APAP-induced liver toxicityby restoring cellular antioxidant defense system, limiting oxidative stress and subsequently protecting mitochondrial dysfunction and inflammation. Recent experimental evidences indicat that these phytochemicals also regulate differential gene expression to modulate various cellular pathways that are implicated in cellular protection. Therefore, in this review, we highlight the role of the phytochemicals, which are shown to be efficacious in clinically relevant APAP-induced hepatotoxicity experimental models. In this review, we have made comprehensive attempt to delineate the molecular mechanism and the cellular targets that are modulated by the phytochemicals to mediate the cytoprotective effect against APAP-induced hepatotoxicity. In this review, we have also defined the challenges and scope of phytochemicals to be developed as drugs to target APAP-induced hepatotoxicity.

Behavior and histopathology as biomarkers for evaluation of the effects of paracetamol and propranolol in the neotropical fish species Phalloceros harpagos

Pharmaceutical drugs in the aquatic environment can induce adverse effects on nontarget organisms. This study aimed to assess the short-term effects of sublethal concentrations of both paracetamol and propranolol on the fish Phalloceros harpagos, specifically light/dark preference, swimming patterns, skin pigmentation, histopathology, and liver glycogen levels. Fish were acutely exposed to sublethal concentrations of both paracetamol (0.008, 0.08, 0.8, 8, 80 mg L^-1) and propranolol (0.0001, 0.001, 0.01, 0.1, 1 mg L^-1) under controlled conditions. For scototaxis, a significant preference for the dark compartment was observed for the group exposed to the highest concentration of paracetamol (80 mg L^-1). Propranolol exposure significantly altered the swimming pattern, especially in fish exposed to the 0.001 mg L^-1 concentration. Pigmentation was reduced in propranolol-exposed fish (0.1, 1 mg L^-1). The lowest concentration of propranolol (0.0001 mg L^-1) induced a decrease of histochemical reaction for hepatic glycogen. These data demonstrate that pharmaceuticals can induce sublethal effects in nontarget organisms, even at low concentrations, compromising specific functions of the individual with ecological relevance, such as energy balance and behavior.

Mechanisms of acetaminophen-induced liver injury and its implications for therapeutic interventions

Acetaminophen (APAP) overdose is the leading cause of drug-induced acute liver failure in many developed countries. Mitochondrial oxidative stress is considered to be the predominant cellular event in APAP-induced liver injury. Accordingly, N-acetyl cysteine, a known scavenger of reactive oxygen species (ROS), is recommended as an effective clinical antidote against APAP-induced acute liver injury (AILI) when it is given at an early phase; however, the narrow therapeutic window limits its use. Hence, the development of novel therapeutic approaches that can offer broadly protective effects against AILI is clearly needed. To this end, it is necessary to better understand the mechanisms of APAP hepatotoxicity. Up to now, in addition to mitochondrial oxidative stress, many other cellular processes, including phase I/phase II metabolism, endoplasmic reticulum stress, autophagy, sterile inflammation, microcirculatory dysfunction, and liver regeneration, have been identified to be involved in the pathogenesis of AILI, providing new targets for developing more effective therapeutic interventions against APAP-induced liver injury. In this review, we summarize intracellular and extracellular events involved in APAP hepatotoxicity, along with emphatic discussions on the possible therapeutic approaches targeting these different cellular events.

The role of apoptosis in acetaminophen hepatotoxicity

Although necrosis is recognized as the main mode of cell death induced by acetaminophen (APAP) overdose in animals and humans, more recently an increasing number of publications, especially in the herbal medicine and dietary supplement field, claim an important contribution of apoptotic cell death in the pathophysiology. However, most of these conclusions are based on parameters that are not specific for apoptosis. Therefore, the objective of this review was to re-visit the key signaling events of receptor-mediated apoptosis and APAP-induced programmed necrosis and critically analyze the parameters that are being used as evidence for apoptotic cell death. Both qualitative and quantitative comparisons of parameters such as Bax, Bcl-2, caspase processing and DNA fragmentation in both modes of cell death clearly show fundamental differences between apoptosis and cell death induced by APAP. These observations together with the lack of efficacy of pan-caspase inhibitors in the APAP model strongly supports the conclusion that APAP hepatotoxicity is dominated by necrosis or programmed necrosis and does not involve relevant apoptosis. In order not to create a new controversy, it is important to understand how to use these "apoptosis" parameters and properly interpret the data. These issues are discussed in this review.

Effect of curcumin on vascular endothelial growth factor in hypoxic HepG2 cells via the insulin-like growth factor 1 receptor signaling pathway

To investigate the anti-angiogenic effect and underlying molecular mechanisms of curcumin on HepG2 cells under hypoxic conditions, insulin-like growth factor 1 receptor (IGF-1R) knockout HepG2 cells were constructed using a clustered regularly interspaced short palindromic repeats/Cas9 genome-editing system. Hypoxic conditions were generated using cobalt chloride (CoCl₂). An MTT assay was performed to measure the effects of curcumin on cell viability in hypoxia-induced IGF-1R knockout HepG2 cells, while western blot analysis was used to detect the expression of IGF-1R, phosphorylated (p)-protein kinase B (Akt), p-extracellular signal-regulated kinases (Erk)1/2, hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF). The results revealed that CoCl₂ at low concentrations (50 and 100 µM) had no significant inhibitory effects on IGF-1R knockout HepG2 cells. However, with increasing concentrations of CoCl₂ and treatment time, cell viability decreased and was significantly reduced at 150, 200 and 400 µM compared with the control group (P<0.05). The expression of HIF-1α and VEGF were significantly increased when the cells were treated with 150 or 200 µM CoCl₂ compared with the control (P<0.05). With the increase of CoCl₂ concentration or the treatment time, the expression of HIF-1α and VEGF were upregulated gradually. Additionally, curcumin significantly inhibited the expression of p-Akt, p-Erk1/2, HIF-1α and VEGF in hypoxia-induced IGF-1R knockout HepG2 cells. In conclusion, the findings of the present study suggest that curcumin may serve a pivotal role in tumor suppression via the inhibition of IGF-1R-mediated angiogenesis under hypoxic conditions.

Exogenous recombinant human thioredoxin-1 prevents acetaminophen-induced liver injury by scavenging oxidative stressors, restoring the thioredoxin-1 system and inhibiting receptor interacting protein-3 overexpression

Thioredoxin-1 (Trx-1) is a potent therapeutic agent against a variety of diseases because of its actions as an antioxidant and regulator of apoptosis. N-acetyl-p-aminophenol (APAP), commonly known as acetaminophen, generates excessive oxidative stress and triggers hepatocyte cell death, exemplified by regulated necrosis. In the present study, we investigated whether APAP-induced liver injury in a mouse model is associated with "necroptosis," and if pretreatment with recombinant Trx-1 prevents the hepatic injury caused by APAP overdose. We also explored the mechanism underlying the preventive action of Trx-1 against APAP-induced hepatic injury. In a prevention study, C3H/he mice received different doses (0, 10, 50 or 100 mg kg^-1 body weight) of recombinant human Trx-1 intraperitoneally, followed by a single oral dose of 300 mg kg^-1 of APAP. In this experimental paradigm, liver injury and lethality were markedly decreased in rhTrx-1-pretreated mice. In survival experiments, mice received rhTrx-1 followed by oral administration of a lethal dose of APAP. APAP overdose caused a series of liver toxicity-associated events, beginning with overexpression of c-fos, excessive production of reactive oxygen species and reactive nitrogen species (RNS) and leading to decreased endogenous Trx-1 expression and activation of JNK signaling pathways. Pretreatment with rhTrx-1 inhibited all of these toxicological manifestations of APAP. In addition, rhTrx-1 significantly reduced the expression of RIP-3, a critical necrosome component. Taken together, our findings indicate that rhTrx-1 prevents APAP-induced liver injury through multiple action mechanisms, including scavenging reactive oxygen species and reactive nitrogen species, restoring endogenous Trx-1 levels and inhibiting RIP-3 overexpression.

Polydatin protects against acetaminophen-induced hepatotoxicity in mice via anti-oxidative and anti-apoptotic activities

Polydatin protects against acetaminophen-induced hepatotoxicity in mice.

Acetaminophen-Induced Liver Injury Alters the Acyl Ethanolamine-Based Anti-Inflammatory Signaling System in Liver

Protective mechanisms against drug-induced liver injury are actively being searched to identify new therapeutic targets. Among them, the anti-inflammatory N-acyl ethanolamide (NAE)-peroxisome proliferators activated receptor alpha (PPARα) system has gained much interest after the identification of its protective role in steatohepatitis and liver fibrosis. An overdose of paracetamol (APAP), a commonly used analgesic/antipyretic drug, causes hepatotoxicity, and it is being used as a liver model. In the present study, we have analyzed the impact of APAP on the liver NAE-PPARα system. A dose-response (0.5-5-10-20 mM) and time-course (2-6-24 h) study in human HepG2 cells showed a biphasic response, with a decreased PPARα expression after 6-h APAP incubation followed by a generalized increase of NAE-PPARα system-related components (PPARα, NAPE-PLD, and FAAH), including the NAEs oleoyl ethanolamide (OEA) and docosahexaenoyl ethanolamide, after a 24-h exposure to APAP. These results were partially confirmed in a time-course study of mice exposed to an acute dose of APAP (750 mg/kg). The gene expression levels of Pparα and Faah were decreased after 6 h of treatment and, after 24 h, the gene expression levels of Nape-pld and Faah, as well as the liver levels of OEA and palmitoyl ethanolamide, were increased. Repeated APAP administration (750 mg/kg/day) up to 4 days also decreased the expression levels of PPARα and FAAH, and increased the liver levels of NAEs. A resting period of 15 days completely restored these impairments. Liver immunohistochemistry in a well-characterized human case of APAP hepatotoxicity confirmed PPARα and FAAH decrements. Histopathological and hepatic damage (Cyp2e1, Caspase3, αSma, Tnfα, and Mcp1)-related alterations observed after repeated APAP administration were aggravated in the liver of Pparα-deficient mice. Our results demonstrate that the anti-inflammatory NAE-PPARα signaling system is implicated in liver toxicity after exposure to APAP overdose, and may contribute to its recovery through a long-term time-dependent response.

The natural compound 7-epiclusianone inhibits superoxide dismutase activity in Schistosoma mansoni

Schistosomiasis - caused by trematodes from the genus Schistosoma - affects more than 200 million people worldwide. Growing resistance to therapy with praziquantel (PZQ) has encouraged the search for novel treatments against this neglected disease. The compound 7-epiclusianone (7-epi) - isolated from 'bacupari' (the fruit of the Gracinia brasiliensis tree) - has promising activity against Schistosoma mansoni in vitro, damaging the parasite's tegument. However, the target and mechanism of action of 7-epi have not been identified. Here, we examined the possibility that 7-epi harms the tegument by inhibiting parasite superoxide dismutase (SOD), which protects the tegument from damage by reactive oxygen species produced by host immune cells. Molecular docking analysis in silico suggested strong interactions between 7-epi and S. mansoni cytosolic superoxide dismutase (SmCtSOD) at allosteric cavities. Schistosoma mansoni couples were cultivated ex vivo with 12.44-198.96 μm 7-epi for 24 h, and then parasite extracts were tested for lipid peroxidation (as a surrogate for oxidative stress), and SOD activity and expression. Lipid peroxidation levels increased after incubation with concentrations ≥99.48 μm 7-epi, and this compound reduced SOD activity at concentrations ≥24.87 μm. However, contact with 7-epi did not alter SOD expression, by quantitative real-time polymerase chain reaction (qRT-PCR). Our results show that the inhibition of SmCtSOD is partly responsible for the tegument detachment observed after incubation with 7-epi, but is not the only cause of the antiparasitic action of this compound in vitro.

Expression of glutathione S-transferase A1, a phase II drug-metabolizing enzyme in acute hepatic injury on mice

In the present study, three models of acute liver injury in mice were induced via the administration of CCl₄ (35 mg/kg, 24 h), acetyl-para-aminophenol (APAP; 200 mg/kg, 12 h) and ethanol (14 ml/kg, 8 h) to study the effect of glutathione S-transferase A1 (GSTA1) on acute liver injury. The serum levels of alanine transaminase, aspartate transaminase and liver homogenate indicators (superoxide dismutase, glutathione and glutathione peroxidase) were significantly lower in model groups compared with the control group (P<0.01), whereas the liver homogenate indicator malondialdehyde was significantly increased (P<0.01). The expression of GSTA1 in liver was significantly decreased in the model groups compared with the control group (P<0.01). GSTA1 protein content was 3.8, 1.3 and 2.6 times lower in the CCl_4, APAP and ethanol model groups, respectively. Furthermore, GSTA1 mRNA expression levels decreased by 4.9, 2.1 and 3.7 times in the CCl_4, APAP and ethanol model groups, respectively. Among the three models, the injury induced by CCl₄ was the most marked, followed by ethanol and finally APAP. These results suggest that GSTA1 may be released by the liver and serve as an antioxidant in the prevention of liver damage.

Effect of blueberry on expression of Bcl-2 and Bax in non-alcoholic fatty liver disease in mice

AIM: To investigate the effect of blueberry on non-alcoholic fatty liver disease in mice and the underlying mechanism.

METHODS: Forty healthy SD mice were randomly divided into a normal control group, a blueberry group, a curcumin group and a model group. The normal control group was given a normal diet, and the other groups were all given a high fat diet. The blueberry group was intragastrically given blueberry juice [15 mL/(kg•d)], the curcumin group was given curcumin solution [200 mg/(kg•d)], and the other groups were given physiological saline daily. At the end of 12 wk, all mice were sacrificed. Liver cell injury and fat deposition were assessed by HE staining and oil red O staining, respectively. The levels of alanine transaminase (ALT), aspartate transaminase (AST), triglyeride (TG) and total cholesterol (TC) in serum were detected with an automatic biochemical analyzer. Hepatic TG, TC, malondialdehyde (MDA), glutathione (GSH) and superoxide dismutase (SOD) were quantified by ELISA. The expression of Bcl-2 and Bax in liver tissue was detected by immunohistochemistry, Western blot and RT-PCR.

RESULTS: Compared to the model group, the blueberry and curcumin groups showed significantly decreased lipid accumulation, serum levels of ALT, AST, TG and TC (P < 0.01), and hepatic levels of TG and MDA (P < 0.01), and increased GSH contents and SOD activity (P < 0.01). Compared to the model group, the blueberry and curcumin groups also showed significantly increased Bcl-2 mRNA and protein expression (P < 0.01), significantly decreased Bax mRNA and protein expression (P < 0.01), and significantly increased Bcl-2/Bax ratio (P < 0.01).

CONCLUSION: Blueberry has a protective effect on non-alcoholic fatty liver disease in mice, and the mechanism may be associated with up-regulating the Bcl-2 expression, down-regulating Bax expression, correcting balance disorders, and enhancing the body's antioxidant ability to inhibit liver cell apoptosis.

Different Contribution of Redox-Sensitive Transient Receptor Potential Channels to Acetaminophen-Induced Death of Human Hepatoma Cell Line

Acetaminophen (APAP) is a safe analgesic antipyretic drug at prescribed doses. Its overdose, however, can cause life-threatening liver damage. Though, involvement of oxidative stress is widely acknowledged in APAP-induced hepatocellular death, the mechanism of this increased oxidative stress and the associated alterations in Ca²⁺ homeostasis are still unclear. Among members of transient receptor potential (TRP) channels activated in response to oxidative stress, we here identify that redox-sensitive TRPV1, TRPC1, TRPM2, and TRPM7 channels underlie Ca²⁺ entry and downstream cellular damages induced by APAP in human hepatoma (HepG2) cells. Our data indicate that APAP treatment of HepG2 cells resulted in increased reactive oxygen species (ROS) production, glutathione (GSH) depletion, and Ca²⁺ entry leading to increased apoptotic cell death. These responses were significantly suppressed by pretreatment with the ROS scavengers N-acetyl-L-cysteine (NAC) and 4,5-dihydroxy-1,3-benzene disulfonic acid disodium salt monohydrate (Tiron), and also by preincubation of cells with the glutathione inducer Dimethylfumarate (DMF). TRP subtype-targeted pharmacological blockers and siRNAs strategy revealed that suppression of either TRPV1, TRPC1, TRPM2, or TRPM7 reduced APAP-induced ROS formation, Ca²⁺ influx, and cell death; the effects of suppression of TRPV1 or TRPC1, known to be activated by oxidative cysteine modifications, were stronger than those of TRPM2 or TRPM7. Interestingly, TRPV1 and TRPC1 were labeled by the cysteine-selective modification reagent, 5,5′-dithiobis (2-nitrobenzoic acid)-2biotin (DTNB-2Bio), and this was attenuated by pretreatment with APAP, suggesting that APAP and/or its oxidized metabolites act directly on the modification target cysteine residues of TRPV1 and TRPC1 proteins. In human liver tissue, TRPV1, TRPC1, TRPM2, and TRPM7 channels transcripts were localized mainly to hepatocytes and Kupffer cells. Our findings strongly suggest that APAP-induced Ca²⁺ entry and subsequent hepatocellular death are regulated by multiple redox-activated cation channels, among which TRPV1 and TRPC1 play a prominent role.