APAP-induced Oxidative Stress Research Articles

Network pharmacology and experimental validation of effects of total saponins extracted from Abrus cantoniensis Hance on acetaminophen-induced liver injury

Ethnopharmacological relevanceAbrus cantoniensis Hance (AC), an abrus cantoniensis herb, is a Chinese medicinal herb used for the treatment of hepatitis. Total saponins extracted from AC (ACS) are a compound of triterpenoid saponins, which have protective properties against both chemical and immunological liver injuries. Nevertheless, ACS has not been proven to have an influence on drug-induced liver injury (DILI). Aim of the studyThis study used network pharmacology and experiments to investigate the effects of ACS on acetaminophen (APAP)-induced liver injury. Materials and methodsThe targets associated with ACS and DILI were obtained from online databases. Cytoscape software was utilized to construct a “compound-target” network. In addition, Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were used to analyze the related signaling pathways impacted by ACS. AutoDock Vina was utilized to evaluate the binding affinity between bioactive compounds and the key targets. To validate the findings of network pharmacology, in vitro and in vivo experiments were conducted. Cell viability assay, transaminase activity detection, immunofluorescence assay, immunohistochemistry staining, RT-qPCR, and western blotting were utilized to explore the effects of ACS. Results25 active compounds and 217 targets of ACS were screened, of which 94 common targets were considered as potential targets for ACS treating APAP-induced liver injury. GO and KEGG analyses showed that the effects of ACS exert their effects on liver injury through suppressing inflammatory response, oxidative stress, and apoptosis. Molecular docking results demonstrated that core active compounds of ACS were successfully docked to core targets such as CASP3, BCL2L1, MAPK8, MAPK14, PTGS2, and NOS2. In vitro experiments showed that ACS effectively attenuated APAP-induced damage through suppressing transaminase activity and attenuating apoptosis. Furthermore, in vivo studies demonstrated that ACS alleviated pathological changes in APAP-treated mice and attenuated inflammatory response. Additionally, ACS downregulated the expression of iNOS, COX2, and Caspase-3, and upregulated the expression of Bcl-2. ACS also suppressed the MAPK signaling pathway. ConclusionsThis study demonstrated that ACS is a hepatoprotective drug through the combination of network pharmacology and in vitro and in vivo experiments. The findings reveal that ACS effectively attenuate APAP-induced oxidative stress, apoptosis, and inflammation through inhibiting the MAPK signaling pathway. Consequently, this research offers novel evidence supporting the potential preventive efficacy of ACS.

Acetaminophen overdose-induced acute liver injury can be alleviated by static magnetic field.

Acetaminophen (APAP), the most frequently used mild analgesic and antipyretic drug worldwide, is implicated in causing 46% of all acute liver failures in the USA and between 40% and 70% in Europe. The predominant pharmacological intervention approved for mitigating such overdose is the antioxidant N-acetylcysteine (NAC); however, its efficacy is limited in cases of advanced liver injury or when administered at a late stage. In the current study, we discovered that treatment with a moderate intensity static magnetic field (SMF) notably reduced the mortality rate in mice subjected to high-dose APAP from 40% to 0%, proving effective at both the initial liver injury stage and the subsequent recovery stage. During the early phase of liver injury, SMF markedly reduced APAP-induced oxidative stress, free radicals, and liver damage, resulting in a reduction in multiple oxidative stress markers and an increase in the antioxidant glutathione (GSH). During the later stage of liver recovery, application of vertically downward SMF increased DNA synthesis and hepatocyte proliferation. Moreover, the combination of NAC and SMF significantly mitigated liver damage induced by high-dose APAP and increased liver recovery, even 24 h post overdose, when the effectiveness of NAC alone substantially declines. Overall, this study provides a non-invasive non-pharmaceutical tool that offers dual benefits in the injury and repair stages following APAP overdose. Of note, this tool can work as an alternative to or in combination with NAC to prevent or minimize liver damage induced by APAP, and potentially other toxic overdoses.

Phytochemicals from Anneslea fragrans Wall. and Their Hepatoprotective and Anti-Inflammatory Activities.

Anneslea fragrans Wall., popularly known as "Pangpo tea", is an edible, medicinal, and ornamental plant of the Family Theaceae. The leaves of A. fragrans were historically applied for the treatment of liver and intestinal inflammatory diseases in China. This study aimed to explore the hepatoprotective agents from A. fragrans leaves through hepatoprotective and anti-inflammatory assessment. The phytochemical investigation of the leaves of A. fragrans resulted in the isolation and identification of a total of 18 chemical compounds, including triterpenoids, aliphatic alcohol, dihydrochalcones, chalcones, flavanols, phenolic glycoside, and lignans. Compounds 1-2, 4-6, 11-12, and 16-18 were identified from A. fragrans for the first time. Compounds 7 and 14 could significantly alleviate hepatocellular damage by decreasing the contents of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) and inhibit the hepatocellular apoptosis in the HepG2 cells induced by N-acetyl-p-aminophenol (APAP). In addition, compounds 7 and 14 inhibited reactive oxygen species (ROS) and malondialdehyde (MDA) contents and increased the catalase (CAT) superoxide dismutase (SOD), and glutathione (GSH) levels for suppressing APAP-induced oxidative stress. Additionally, compounds 7, 13, and 14 also had significant anti-inflammatory effects by inhibiting interleukin-6 (IL-6), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α) productions on LPS-induced RAW246.7 cells.

Phenelzine protects against acetaminophen induced apoptosis in HepG2 cells

Acetaminophen (APAP) overdosing is the most common cause of drug-induced liver failure. Despite extensive study, N-acetylcysteine is currently the only antidote utilized for treatment. The purpose of this study was to evaluate the effect and mechanisms of phenelzine, an FDA-approved antidepressant, on APAP-induced toxicity in HepG2 cells. The human liver hepatocellular cell line HepG2 was used to investigate APAP-induced cytotoxicity. The protective effects of phenelzine were determined by examining the cell viability, combination index calculation, Caspase 3/7 activation, Cytochrome c release, H2O2 levels, NO levels, GSH activity, PERK protein levels, and pathway enrichment analysis. Elevated H2O2 production and decreased glutathione (GSH) levels were indicators of APAP-induced oxidative stress. The combination index of 2.04 indicated that phenelzine had an antagonistic effect on APAP-induced toxicity. When compared to APAP alone, phenelzine treatment considerably reduced caspase 3/7 activation, cytochrome c release, and H2O2 generation. However, phenelzine had minimal effect on NO and GSH levels and did not alleviate ER stress. Pathway enrichment analysis revealed a potential connection between APAP toxicity and phenelzine metabolism. These findings suggested that phenelzine’s protective effect against APAP-induced cytotoxicity could be attributed to the drug’s capacity to reduce APAP-mediated apoptotic signaling.

Hepatoprotective Effects of Biochanin A Against Acetaminophen-induced Liver Toxicity in Mice

Background: Acetaminophen (APAP), a common analgesic agent, is hepatotoxic in overdose. N-acetylcysteine (NAC), as an APAP antidote, shows anaphylactic reactions and has low efficacy in APAP poisoning in high doses. Objectives: This study was designed to examine the hepatoprotective effect of biochanin A (BA) in a mice model of acetaminophen-induced hepatotoxicity. Methods: To evaluate APAP-induced oxidative stress, the liver tissue level of malondialdehyde (MDA) and glutathione (GSH) and the activities of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), catalase, and superoxide dismutase (SOD) were measured. Histological analysis was performed. Results: APAP-induced hepatotoxicity was manifested by inflammation, acinar hepatic necrosis, and fatty degeneration, as well as an increase in the levels of ALP, ALT, AST, MDA, and a decrease in the SOD, catalase (CAT), and GSH. Pre-treatment with BA at low doses (10 and 20 mg/kg) reduced ALT, AST, and MDA levels and raised the SOD, GSH, and CAT levels. Moreover, it normalized the structure of liver tissue. Conclusions: The results of this study indicated that BA protected the liver from APAP-induced injury. Protection may be due to the inhibition of oxidative stress, which reduces liver inflammation.

Narirutin activates TFEB (transcription factor EB) to protect against Acetaminophen-induced liver injury by targeting PPP3/calcineurin

ABSTRACT Acetaminophen (APAP) overdose is the predominant cause of drug-induced liver injury worldwide. The macroautophagy/autophagy-lysosomal pathway (ALP) is involved in the APAP hepatotoxicity. TFEB (transcription factor EB) promotes the expression of genes related to autophagy and lysosomal biogenesis, thus, pharmacological activation of TFEB-mediated ALP may be an effective therapeutic approach for treating APAP-induced liver injury. We aimed to reveal the effects of narirutin (NR), the main bioactive constituents isolated from citrus peels, on APAP hepatotoxicity and to explore its underlying mechanism. Administration of NR enhanced activities of antioxidant enzymes, improved mitochondrial dysfunction and alleviated liver injury in APAP-treated mice, whereas NR did not affect APAP metabolism and MAPK/JNK activation. NR enhanced TFEB transcriptional activity and activated ALP in an MTOR complex 1 (MTORC1)-independent but PPP3/calcineurin-dependent manner. Moreover, knockout of Tfeb or knockdown of PPP3CB/CNA2 (protein phosphatase 3, catalytic subunit, beta isoform) in the liver abolished the beneficial effects of NR on APAP overdose. Mechanistically, NR bound to PPP3CB via PRO31, LYS61 and PRO347 residues and enhanced PPP3/calcineurin activity, thereby eliciting dephosphorylation of TFEB and promoting ALP, which alleviated APAP-induced oxidative stress and liver injury. Together, NR protects against APAP-induced liver injury by activating a PPP3/calcineurin-TFEB-ALP axis, indicating NR may be a potential agent for treating APAP overdose. Abbreviations: ALP: autophagy-lysosomal pathway; APAP: acetaminophen; APAP-AD: APAP-protein adducts; APAP-Cys: acetaminophen-cysteine adducts; CAT: catalase; CETSA: cellular thermal shift assay; CQ: chloroquine; CYP2E1: cytochrome P450, family 2, subfamily e, polypeptide 1; CYCS/Cyt c: cytochrome c, somatic; DARTS: drug affinity responsive target stability assay; ENGASE/NAG: endo-beta-N-acetylglucosaminidase; GOT1/AST: glutamic-oxaloacetic transaminase 1, soluble; GPT/ALT: glutamic pyruvic transaminase, soluble; GSH: glutathione; GPX/GSH-Px: glutathione peroxidase; KD: dissociation constant; Leu: leupeptin; MCOLN1: mucolipin 1; MTORC1: MTOR complex 1; NAC: N-acetylcysteine; NAPQI: N-acetyl-p-benzoquinoneimine; NFAT: nuclear factor of activated T cells; NR: narirutin; OA: okadaic acid; RRAG: Ras related GTP binding; ROS: reactive oxygen species; PPP3CB/CNA2: protein phosphatase 3, catalytic subunit, beta isoform; PPP3R1/CNB1: protein phosphatase 3, regulatory subunit B, alpha isoform (calcineurin B, type I); SOD: superoxide dismutase; SPR: surface plasmon resonance analysis; TFEB: transcription factor EB.

Water extract of lotus leaves has hepatoprotective activity by enhancing Nrf2- and epigenetics-mediated cellular antioxidant capacity in mouse hepatocytes

• The main phenolics in LL-WE were EGCG, rutin, gallic acid, myricetin, quercetin, ellagic acid, etc. • LL-WE reduced the damage of mouse AML-12 hepatocytes caused by APAP-induced oxidative stress. • LL-WE promoted glutathione synthesis and activated the Nrf2 pathway. • LL-WE upregulated Nrf2-mediated antioxidant enzymes and downregulated HDACs and DNMTs. • LL-WE inhibited the in vitro activity of CpG methyltransferase (M.SssI). The liver is an important organ in the human body; however, studies have shown that the excessive intake of acetaminophen (APAP), the primary ingredient in marketing pain relievers, may cause oxidative damage to liver cells. Here we found that lotus leaf water extract (LL-WE) enriched with various phenolic compounds can prevent mice AML-12 hepatocytes from APAP-induced injury, and trigger the Nrf2 pathway in HepG2-C8 cells with ARE-luciferase plasmid. LL-WE effectively induced Nrf2 nuclear translocation and glutathione synthesis, increased gene expression of antioxidant enzymes (HO-1, NQO1, and UGT1A), and reduced protein levels of epigenetic modification enzymes (HDACs and DNMTs) in AML-12 cells. LL-WE also inhibited the activity of M.SssI CpG methyltransferase in vitro . These results suggest that LL-WE can be a potential hepatoprotective agent to reduce oxidative stress-induced liver damage by activating the Nrf2 pathway and downregulating epigenetic modification enzymes.

Inhibition of fucosylation by 2-fluorofucose attenuated acetaminophen-induced liver injury via its anti-inflammation and anti-oxidative stress effects.

Fucosylation is a common glycan terminal modification, which has been reported to be inhibited by 2-fluorofucose (2FF) both in vivo and in vitro. The present study aimed to investigate the effect of 2FF on acetaminophen (APAP)-induced acute liver injury, and further clarified the possible mechanisms. In the present study, inhibition of fucosylation by 2FF relieved APAP-induced acute liver injury in vivo. Pretreatment with 2FF remarkably suppressed APAP-induced oxidative stress and mitochondria damage. 2FF markedly enhanced the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and simultaneously promoted the expression of downstream proteins including HO-1 and NQO1. Furthermore, pretreatment with 2FF significantly suppressed the expression of inflammation-associated proteins, such as COX2 and iNOS. The data from lectin blot assay revealed that the alteration of α1,6-fucosylation was involved in APAP-induced acute liver injury. The second part of this study further confirmed that the enhancements to antioxidant capacity of 2FF pretreatment and α1,6-fucose deficiency were related to Nrf2/keap1 and NF-κB signaling pathways in HepG2 cells. Taken together, the current study suggested that 2FF might have a potential therapeutic effect for APAP-induced acute liver injury.

Lipid-lowering, anti-inflammatory, and hepatoprotective effects of isorhamnetin on acetaminophen-induced hepatotoxicity in mice

Isorhamnetin is a hepatoprotective flavonoid molecule derived from the leaves and fruits of Hippophae rhamnoides L. However, the protective effect of isorhamnetin on acetaminophen (APAP) induced hepatotoxicity is still unknown. Thus, we aimed to investigate the lipid-lowering, anti-inflammatory, and hepatoprotective effects of isorhamnetin on APAP-induced hepatotoxicity in mice. Hepatotoxicity was induced by a single injection of APAP (300 mg/kg, intraperitoneally). Isorhamnetin (50 or 100 mg/kg, orally) and N-acetylcysteine (NAC) (200 mg/kg, orally), or vehicle control, were administered 1 h before the administration of APAP. Total antioxidant status (TAS) and total oxidative status (TOS) of liver tissue and levels of inflammatory factors (TNF-α, IL-1β, and IL-6) were analyzed by ELISA. Lipid profiles and liver function parameters were measured using an autoanalyzer. In addition, liver tissue was examined histopathologically. Isorhamnetin treatment significantly reduced the APAP-induced increase in the liver weight and liver index; it also reduced the APAP-induced increase in serum liver parameters (ALT, AST, ALP, and LDH) (p < 0.05). Isorhamnetin significantly reduced APAP-induced oxidative stress and inflammation by increasing TAS levels and decreasing TOS, TNF-α, IL-1β, and IL-6 levels (p < 0.05). Moreover, isorhamnetin treatment significantly regulated lipid profiles (TG, T-C, LDL-C, and HDL-C levels) that changed in response to APAP administration (p < 0.05). In histopathological examination, liver degeneration observed in the APAP group was significantly reduced in the NAC and isorhamnetin-treated groups (p < 0.05). This study suggests that isorhamnetin has a significant protective effect on APAP-induced hepatotoxicity in mice through its lipid-lowering, antioxidant, and anti-inflammatory effects.

Cajaninstilbene Acid Ameliorates Acetaminophen-Induced Liver Injury Through Enhancing Sestrin2/AMPK-Mediated Mitochondrial Quality Control.

Acetaminophen (APAP)-induced liver injury (AILI) is the main cause of acute liver failure in the developed countries. The present study aimed to evaluate the therapeutic efficacy of cajaninstilbene acid (CSA), a major stilbene compound derived from the leaves of pigeon pea [Cajanus cajan (L.) Millsp.], against AILI. CSA (50, 75 mg/kg, p. o.) was administered to male C57BL/6 N mice 0.5 h after a toxic dose of APAP (300 mg/kg, i. p.). The direct effect of CSA on hepatocytes was tested on primary mouse hepatocytes. Serum transaminases, hematoxylin and eosin staining, TUNEL and propidium iodide staining were used to assess hepatic damage and cell death. The results demonstrated that APAP-induced liver injury was ameliorated by CSA, as evidenced by decreased alanine aminotransferase and aspartate aminotransferase levels in the serum, and fewer necrotic and apoptotic hepatocytes in vitro and in vivo. Consequently, the inflammation in response to APAP overdose was inhibited by CSA. Without affecting APAP metabolic activation, CSA interrupted the sustained JNK-Sab-ROS activation loop and alleviated oxidative stress. Additionally, CSA promoted mitochondrial quality control, including mitochondrial biogenesis and mitophagy, as revealed by increased PGC-1α, TFAM, LC3-Ⅱ, PINK1 and mitochondrial Parkin expression and decreased p62 expression. Further mechanistic investigations showed that independent of CAMKK2, LKB1-mediated AMPK activation, which was promoted by Sestrin2, might be responsible for the protective effect of CSA. Our study demonstrates that CSA alleviates APAP-induced oxidative stress and enhanced mitochondrial quality control through Sestrin2/AMPK activation, thereby protecting against AILI,.

Orientin reverses acetaminophen-induced acute liver failure by inhibiting oxidative stress and mitochondrial dysfunction

Oxidative stress, as an important pathogenic factor, plays a critical role in acetaminophen (APAP) overdose-induced acute liver failure (ALF). Thus, an antioxidative strategy may be a good way to alleviate APAP-induced liver damage. Previous research has reported that Orientin (Ori) possesses antioxidant, anti-inflammatory and anticancer effects. This study aimed to explore whether Ori can protect against APAP-induced oxidative stress and to elucidate its underlying mechanism. Our results indicated that Ori alleviated APAP-induced hepatic pathological changes by reducing mouse mortality, inhibiting the expression of cytochrome P450 2E1 (CYP2E1), maintaining a normal liver structure, and reducing the levels of serum alanine transaminase (ALT) and serum aspartate aminotransferase (AST). Moreover, Ori protected against APAP-induced oxidative damage by decreasing the formation of malondialdehyde (MDA) and myeloperoxidase (MPO) and increasing the levels of superoxide dismutase (SOD) and the GSH-to-GSSG ratio. Moreover, Ori regulated APAP-induced hepatocyte apoptosis and mitochondrial dysfunction by inhibiting cytochrome c mitochondrial translocation and c-jun N-terminal kinase phosphorylation, promoting Bcl-2 expression and reducing Bax and caspase-3 cleavage. Furthermore, Ori not only obviously promoted Nrf2 nuclear translocation but also activated the antioxidant-related proteins HO-1, GCLC, GCLM and NQO1. Therefore, Ori prevented APAP-induced hepatocyte oxidative damage and mitochondrial dysfunction via Nrf2-mediated and JNK/cytochrome c/caspase-3 signaling pathways.

Akkermansia muciniphila Ameliorates Acetaminophen-Induced Liver Injury by Regulating Gut Microbial Composition and Metabolism.

ABSTRACTThe gut microbiota drives individual sensitivity to excess acetaminophen (APAP)-mediated hepatotoxicity. It has been reported that the bacterium Akkermansia muciniphila protects hosts against liver disease via the liver-gut axis, but its therapeutic potential for drug-induced liver injury remains unclear. In this study, we aimed to investigate the effect of A. muciniphila on APAP-induced liver injury and the underlying mechanism. Administration of A. muciniphila efficiently alleviated APAP-induced hepatotoxicity and reduced the levels of serum alanine aminotransferase (ALT) and aspartate transaminase (AST). A. muciniphila significantly attenuated APAP-induced oxidative stress and the inflammatory response, as evidenced by restoration of the reduced glutathione/oxidized glutathione (GSH/GSSG) balance, enhanced superoxide dismutase (SOD) activity, reduced proinflammatory cytokine production, and alleviation of macrophage and neutrophil infiltration. Moreover, A. muciniphila maintained gut barrier function, reshaped the perturbed microbial community and promoted short-chain fatty acid (SCFA) secretion. The beneficial effects of A. muciniphila were accompanied by alterations in hepatic gene expression at the transcriptional level and activation of the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway. Our results suggested that A. muciniphila could be a potential pretreatment for APAP-induced liver injury.IMPORTANCE Our work revealed that A. muciniphila attenuated APAP-induced liver injury by alleviating oxidative stress and inflammation in the liver, and its hepatoprotective effect was accompanied by activation of the PI3K/Akt pathway and mediated by regulation of the composition and metabolic function of the intestinal microbiota. This finding suggested that the microbial community is a non-negligible impact on drug metabolism and probiotic administration could be a potential therapy for drug-induced liver injury.

Atractylenolide Ⅰ improves acetaminophen-induced acute liver injury in mice by inhibiting MAPK/NF-κB signaling pathway

This study explored the protective effect of atractylenolide Ⅰ(AO-Ⅰ) against acetaminophen(APAP)-induced acute liver injury(ALI) in mice and its underlying mechanism. C57 BL/6 J mice were randomly divided into a control group, an APAP group(500 mg·kg~(-1)), a low-dose combination group(500 mg·kg~(-1) APAP + 60 mg·kg~(-1) AO-Ⅰ), and a high-dose combination group(500 mg·kg~(-1) APAP + 120 mg·kg~(-1) AO-Ⅰ). ALI was induced by intraperitoneal injection of APAP(500 mg·kg~(-1)). AO-Ⅰ by intragastric administration was performed 2 hours before APAP treatment, and the control group received the same dose of solvent by intragastric administration or intraperitoneal injection. The protective effect of AO-Ⅰ against APAP-induced ALI was evaluated by detecting alanine aminotransferase(ALT) and aspartate aminotransferase(AST) levels in the plasma and H&amp;E staining in liver tissues of mice. The malondialdehyde(MDA) and glutathione(GSH) content and catalase(CAT) activity in mouse liver tissues were detected to evaluate the effect of AO-Ⅰ on APAP-induced oxidative stress in the liver. The proteins in the liver p38 mitogen-activated protein kinase(p38 MAPK), c-jun N-terminal kinase(JNK), and nuclear factor kappa-B p65(NF-κB p65) signaling pathways were measured by Western blot, and the liver inflammatory cytokines interleukin-1β(IL-1β) and interleukin-6(IL-6) were detected by real-time PCR. Compared with the APAP group, the combination groups showed reduced APAP-induced ALT level and liver MDA content, potentiated liver CAT activity, and elevated GSH content. Mechanistically, AO-Ⅰ treatment significantly inhibited APAP-up-regulated MAPK phosphorylation and NF-κB p65, and significantly reduced the transcriptional activities of IL-1β and IL-6, downstream targets of NF-κB p65. AO-Ⅰ can improve APAP-induced ALI and the underlying mechanism is related to the inhibition of the MAPK/NF-κB p65 signaling pathway in APAP-challenged mice.

Retraction: The PI3K/Akt and NF-κB signaling pathways are involved in the protective effects of Lithocarpus polystachyus (sweet tea) on APAP-induced oxidative stress injury in mice.

[This retracts the article DOI: 10.1039/D0RA00020E.].

Crocin Possesses Excellent Hepatoprotective Effects Against Acetaminophen-Induced Hepatotoxicity in Mice

Background: Acetaminophen (APAP) is a common analgesic and antipyretic medicine that can lead to acute liver injury at high doses. Crocin, a Crocus sativus’ ingredient, has potent antioxidant effects. Objectives: This study examined the protective effects of crocin against APAP-induced oxidative stress in mice. Methods: In this study, 56 mice were randomly divided into seven groups (n = 8 per group), including the negative (normal saline, 10 mL/kg) and positive (oral normal saline for five days + a single dose of APAP (300 mg/kg) on day 6th) control groups. The third group (NAC) received normal saline for up to five days, and on the 6th day, immediately after the administration of acetaminophen, received NAC (50 mg/kg). Groups fourth to sixth received respectively 12.5, 25, and 50 mg/kg of crocin (orally for six days), followed by a single dose of APAP (300 mg/kg) on 6th day. The last group received crocin (50 mg/kg) for six days. Then 24 h after the last injection, the animals were sacrificed, and samples were collected for biochemical and histopathological evaluations. Results: The levels of ALT, AST, and MDA increased, and the activity of CAT, GSH, and GPX decreased in the APAP-treated group compared to the control group. In APAP-treated groups, the administration of crocin decreased the serum levels of AST, ALT, and MDA and increased the activity of CAT, GSH, and GPX. Histopathological evaluations confirmed the above findings. Conclusions: According to our results, it seems that crocin has a protective effect against acetaminophen-induced liver toxicity and can be used as a therapeutic agent to treat APAP-induced hepatotoxicity.

Comparative characterization of cinnamon, cinnamaldehyde and kaempferol for phytochemical, antioxidant and pharmacological properties using acetaminophen-induced oxidative stress mouse model

This study was aimed to explore the comparative efficacy of cinnamon bark extract, cinnamaldehyde and kaempferol against acetaminophen (APAP)-induced oxidative stress. Cinnamon bark extract, cinnamaldehyde and kaempferol were utilized for in-vivo analysis. From the results of in-vitro screening tests, cinnamon ethanolic extract was selected for in-vivo study in mouse model. For this, Balb/c albino mice were treated with cinnamon ethanolic extract (200 mg/kg), cinnamaldehyde (10 mg/kg) and kaempferol (10 mg/kg) orally for 14 days followed by single intraperitoneal administration of APAP during 8 hours. Blood and organ samples were collected for biochemical and histopathological analysis. The results showed that cinnamon bark ethanolic extract, cinnamaldehyde and kaempferol ameliorated APAP-induced oxidative stress and organ toxicity in mice. In conclusion, cinnamaldehyde and kaempferol possess comparable antioxidant potential even at 20-times less dose as compared to cinnamon bark ethanolic extract suggesting therapeutic potential in oxidative stress-related disorders.

Chemical Characterization and Hepatoprotective Effects of a Standardized Triterpenoid-Enriched Guava Leaf Extract

Nutraceutical/pharmaceutical agents capable of maintaining redox and inflammation homeostasis are considered as candidates for the prevention and/or treatment of liver diseases. Psidium guajava (commonly known as guava) leaf is a commercially available functional food that has been reported to possess hepatoprotective property. However, the hepatoprotective constituents in guava leaf are not known. In the current study, a standardized triterpenoid-enriched extract of guava leaves (TGL) was developed. A new ursolic acid derivative, namely 2α,3β,6β,23,30-pentahydroxyurs-11,13(18)-dien-28,20β-olide (1), and 23 known triterpenoids were isolated and identified from TGL. The hepatoprotective effects of TGL were evaluated through a model using acetaminophen (APAP)-exposed C57BL/6 male mice. Pretreatment of TGL (75 and 150 mg/kg) restored the mice hepatic architecture, improved the serum ALT and AST levels, and reduced the hepatic ROS and MDA contents. Further molecular mechanistic study revealed that TGL modulated Nrf2 and MAPK signaling pathways to alleviate APAP-induced oxidative and inflammatory stress in liver. In addition, the new compound 1 from TGL showed protective effects against APAP-induced cytotoxicity via activation of the Nrf2 pathway in HepG2 cells. Overall, this is the first report on the hepatoprotective effects of a standardized triterpenoid-enriched extract of guava leaves, which supports its potential nutraceutical application in liver disease management.

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.

Autophagy impairment as a key feature for acetaminophen-induced ototoxicity

Macroautophagy/autophagy is a highly conserved self-digestion pathway that plays an important role in cytoprotection under stress conditions. Autophagy is involved in hepatotoxicity induced by acetaminophen (APAP) in experimental animals and in humans. APAP also causes ototoxicity. However, the role of autophagy in APAP-induced auditory hair cell damage is unclear. In the present study, we investigated autophagy mechanisms during APAP-induced cell death in a mouse auditory cell line (HEI-OC1) and mouse cochlear explant culture. We found that the expression of LC3-II protein and autophagic structures was increased in APAP-treated HEI-OC1 cells; however, the degradation of SQSTM1/p62 protein, the yellow puncta of mRFP-GFP-LC3 fluorescence, and the activity of lysosomal enzymes decreased in APAP-treated HEI-OC1 cells. The degradation of p62 protein and the expression of lysosomal enzymes also decreased in APAP-treated mouse cochlear explants. These data indicate that APAP treatment compromises autophagic degradation and causes lysosomal dysfunction. We suggest that lysosomal dysfunction may be directly responsible for APAP-induced autophagy impairment. Treatment with antioxidant N-acetylcysteine (NAC) partially alleviated APAP-induced autophagy impairment and apoptotic cell death, suggesting the involvement of oxidative stress in APAP-induced autophagy impairment. Inhibition of autophagy by knocking down of Atg5 and Atg7 aggravated APAP-induced ER and oxidative stress and increased apoptotic cell death. This study provides a better understanding of the mechanism responsible for APAP ototoxicity, which is important for future exploration of treatment strategies for the prevention of hearing loss caused by ototoxic medications.

Hesperetin attenuated acetaminophen-induced hepatotoxicity by inhibiting hepatocyte necrosis and apoptosis, oxidative stress and inflammatory response via upregulation of heme oxygenase-1 expression

Acetaminophen (APAP) is a common antipyretic and analgesic drug, but its overdose can induce acute liver failure with lack of effective therapies. Hesperetin, a dihydrogen flavonoid compound, has been revealed to exert multiple pharmacological activities. Here, we explored the protective effects and mechanism of hesperetin on APAP-induced hepatotoxicity. The results showed that pretreatment with hesperetin dose-dependently attenuated APAP-induced acute liver injury in mice, as measured by alleviated serum enzymes activities, hepatic pathological damage and apoptosis. Moreover, hesperetin mitigated APAP-induced oxidative stress and inflammatory response in mice by inhibiting oxidative molecules but increasing antioxidative molecules production, reducing inflammatory cells infiltration and proinflammatory cytokines production, blocking Toll-like receptor (TLR)-4 signal activation. In vitro experiment indicated that hesperetin dose-dependently inhibited APAP-primed cytotoxicity, apoptosis, and reactive oxygen species (ROS) in murine AML12 hepatocytes. Notably, hesperetin up-regulated expression of heme oxygenase-1 (HO-1) mRNA and protein in the liver of mice and AML12 cells exposed to APAP. Furthermore, knockdown of HO-1 by adenovirus-mediated HO-1 siRNA reverted these beneficial effects of hesperetin on APAP-induced hepatocytotoxicity as well as ROS and inflammatory response in vivo and in vitro. These findings demonstrated that hesperetin exerted a protective prophylaxis on APAP-induced acute liver injury by inhibiting hepatocyte necrosis and apoptosis, oxidative stress and inflammatory response via up-regulating HO-1 expression.