Dibenzocyclooctadiene lignans from Kadsura coccinea alleviate APAP-induced hepatotoxicity via oxidative stress inhibition and activating the Nrf2 pathway in vitro.

Phytochemical investigation on the roots of Kadsura coccinea led to the isolation five previously unknown dibenzocyclooctadiene lignans, named heilaohusuins A-E (1-5). Their structures determined by NMR spectroscopy, HR-ESI-MS, and ECD spectra. Hepatoprotection effects of a series of dibenzocyclooctadiene derivatives (1-68) were investigated against acetaminophen (APAP) induced HepG2 cells. Compounds 2, 10, 13, 21, 32, 41, 46, and 49 showed remarkable protective effects, increasing the viabilities to > 52.2% (bicyclol, 52.1 ± 1.3%) at 10 µM. The structure-activity relationships (SAR) for hepatoprotective activity were summarized, according to the activity results of dibenzocyclooctadiene derivatives. Furthermore, we found that one new dibenzocyclooctadiene lignan heilaohusuin B attenuates hepatotoxicity, the mechanism might be closely correlated with oxidative stress inhibition via activating the Nrf2 pathway.

Protective Effect of Phoenix dactylifera L. Seeds against Paracetamol-Induced Hepatotoxicity in Rats: A Comparison with Vitamin C.

Phoenix dactylifera L. (date palm) seeds have been mentioned in the Moroccan pharmacopoeia as efficient remedies against a wide range of diseases including hepatic and gastrointestinal disorders and countless infections. The current work was performed to assess the phenolic profile and hepatoprotective potential of two date seed varieties, locally known as Jihl and Majhoul, aqueous extracts against paracetamol- (PCM-) driven liver toxicity in 42 Wistar rats. The polyphenol profile was built by means of an HPLC analysis. Hepatic damage was provoked by exposing rats to PCM at a dose of 1.5 g/kg once a week. Besides PCM, Jihl and Majhoul date seed extracts (200 and 400 mg/kg) were administered orally in a day-to-day routine. Our findings showed that among the examined polyphenol compounds, p-coumaric acid, quercetin, caffeic acid, and rutin were the most abundant phytochemicals. Date pits significantly (p < 0.001) stabilized the PCM-driven alterations in liver function parameters (AST, ALT, ALP, LDH, total protein, direct bilirubin, and total bilirubin). Moreover, Phoenix dactylifera pits enhanced considerably (p < 0.001) the activities of antioxidant enzymes (SOD, CAT, and GPx) as well as the level of reduced glutathione (GSH). The established hepatoprotective effect may be due to the date seeds antioxidant effect and their ability to trap free radicals. The main outcomes of the present study could validate the traditional use of these date seeds to manage various health conditions.

Protective effect of Heliotropium strigosum 70% aqueous methanolic extract against paracetamol induced hepatotoxicity in mice.

The study was carried out to evaluate the hepatoprotective potential of aqueous methanolic extract of Heliotropium strigosum (HSME) against paracetamol induced hepatotoxicity in Swiss albino mice. The plant powder (1.5Kg) was macerated in aqueous methanol (30:70) for 7 days. The extract was evaluated for the presence of different phytochemicals and High-performance liquid chromatography (HPLC) analysis. HSME was orally administered to mice at 125, 250 and 500mg/kg for 8 days followed by paracetamol intoxication (500mg/kg orally) on the 8th day using silymarin as standard control. All the therapy was administered by oral gavage. The liver biochemical parameters and histopathological evaluation were carried out to assess changes in liver function and histology. HPLC analysis confirmed the presence of quercetin, kaempferol, and other phenolic compounds. Treatment with the extract resulted in notable (p<0.05) reduction in liver parameters in dose dependent manner. The action of HSME 500mg/kg dose was comparable to silymarin. The effect of HSME against paracetamol induced hepatotoxicity was demonstrated by protective changes in the liver histopathological which proved the traditional uses of the plant.

Therapeutic role of Typha elephantina leaves aqueous extract in paracetamol intoxicated rabbits.

Present study is aimed to investigate the hepatoprotective and hematopoietic effect of Typha elephantina leaves aqueous (T.E.AQ), extract in paracetamol (PCM) intoxicated rabbits. Experimental animals were divided into various groups. The blood was taken on day 7th (W1=Week 1), day 14th (W2 = week 2) and day 21st (W3 = week 3) of treatments and was analyzed for all hematological and serum biochemical markers. PCM administration caused marked increase in the levels of serum biochemical and hematological parameters. The leaves of T.E.AQ extract at dose rate 300mg/kg body weight significantly (P<0.05) reduced the elevated levels of serum biochemical and hematological indices towards normal values on third week (day 21st) of treatment while treatment in the first two weeks revealed non-significant effects even at all doses of extract. The levels of glutathione (GSH) and radical scavenging activity (RSA) were reduced and thiobarbituric acid reactive substances (TBARS) levels was high in the PCM feed animals. Administration of (T.E.AQ) extract at high dose (300mg/kg) significantly regulated and normalized these antioxidant values. The antioxidant capacity of (TE.AQ) extract, showed increase inhibition against various extract concentrations on the basis of percent scavenging of (DPPH) free radical. The histological sections of liver further supported the hepatoprotective activity of extract.

Sinomenine Attenuates Acetaminophen-Induced Acute Liver Injury by Decreasing Oxidative Stress and Inflammatory Response via Regulating TGF-ß/Smad Pathway in vitro and in vivo.

INTRODUCTION: Liver disease is common and often life-threatening. Sinomenine (SIN) is an active ingredient extracted from  Sinomenium acutum. This study investigated the protective effect and mechanism of sinomenine (SIN) on acetaminophen (APAP)-induced liver injury from in vitro and in vivo. METHODS: In vivo experiments, mice were randomly divided into six groups (n=10): control group, model group, SIN (25 mg/kg) group, SIN (50 mg/kg) group, SIN (100 mg/kg) group and SIN (100 mg/kg) + SRI-011381 group. Alanine transaminases (ALT), aspartate transaminases (AST) and alkaline phosphatase (ALP) were detected. The pathological lesion was measured by HE staining. Apoptosis was measured by TUNEL staining. In vitro experiments, BRL-3A cells were treated with APAP (7.5 mM) and then subjected to various doses of SIN (10, 50 and 100 µg/mL) at 37°C for 24 h. Inflammatory factors and oxidative stress index were measured by ELISA. The expression of proteins was detected by Western blot. RESULTS: The results showed that compared with the control group, the levels of ALT, AST and ALP in the serum of APAP-induced mice were significantly increased, followed by liver histological damage and hepatocyte apoptosis. Besides, APAP reduced the activity of SOD and GSH-Px, while increasing the content of MDA and LDH. Notably, APAP also promoted the expression of NLRP3, ASC, caspase-1 and IL-1ß. Interestingly, SIN treatment dose-dependently reduced APAP-induced liver injury and oxidative stress, inhibited the activation of NLRP3 inflammasomes, and reduced the levels of inflammatory cytokines. In vitro studies have shown that SIN treatment significantly reduced the viability of BRL-3A cells and oxidative stress and inflammation. In addition, the Western blotting analysis showed that SIN inhibited the activation of TGF-ß/Smad pathway in a dose-dependent manner in vitro and in vivo. These effects were significantly reversed by TGF-ß/Smad activator SRI-011381 or TGF-ß overexpression. DISCUSSION: The study indicates that SIN attenuates APAP-induced acute liver injury by decreasing oxidative stress and inflammatory response via TGF-ß/Smad pathway in vitro and in vivo.

The MAP2K4/JNK/c-Jun Signaling Pathway Plays A Key Role In Dexmedetomidine Protection Against Acetaminophen-Induced Liver Toxicity.

PURPOSE: Dexmedetomidine [DEX; (S)-4-[1-(2,3-dimethylphenyl)ethyl]-3H-imidazole] is a selective α2-adrenergic receptor (α2-AR) agonist that attenuates the liver damage associated with local or systemic inflammation. However, it remains unclear whether DEX has protective effects against acetaminophen (Paracetamol, PARA)-induced liver toxicity (PILT). METHODS: PILT mice were established by intraperitoneal administration of a hepatotoxic dose of acetaminophen (300 mg/kg). Thirty minutes later, the mice were treated with DEX at a concentration of 0, 5, 25, or 50 µg/kg. Blood and liver samples were obtained for further analysis. RESULTS: DEX treatment significantly attenuated PILT in mice, with the strongest beneficial effects at a dose of 25 µg/kg. The levels of hepatic cytokines, tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6), in addition to myeloperoxidase (MPO) activity, were significantly decreased following DEX treatment. Moreover, DEX treatment reduced macrophage recruitment around the area of hepatotoxicity and the expression levels of hepatic phosphorylated mitogen-activated protein kinase kinase 4 (MAP2K4), c-jun N-terminal kinase (JNK), and c-Jun expression induced by acetaminophen overdose. CONCLUSION: The data suggest that DEX likely downregulates the JNK signaling pathway and its downstream effectors to promote its hepatoprotective effect, providing a clinical application of DEX for the attenuation of PILT.

Inhibition of paracetamol-induced acute kidney damage in rats using a combination of resveratrol and quercetin / Inhibición de daño renal agudo inducido por paracetamol en ratas usando una combinación de resveratrol y quercetina

Paracetamol (also called acetaminophen, or APAP) overdose causes acute damage to the liver and kidneys in both humans and experimental animal models via the induction of the oxidative stress pathway. We sought to determine whether the combined antioxidants and anti-inflammatory compounds, resveratrol (RES) and quercetin (QUR) can protect against kidney injury induced by a toxic dose of APAP in a rat model of APAP-induced acute kidney injury. Rats were either received a single dose of APAP (2 g/kg) before being sacrificed after 24 hours or were pre-treated for 7 days with combined doses of RES (30 mg/kg) and QUR (50 mg/kg) before being given a single dose of APAP and then sacrificed 24 hours post APAP ingestion. Harvested kidney tissues were prepared for light microscopy staining, and tissue samples were assayed for (i) biomarkers of oxidative stress and antioxidant, malondialdehyde (MDA) and superoxide dismutase (SOD); and (ii) biomarkers of inflammation, tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6). Hematoxylin and eosin (H&E) stained images showed that APAP overdose induced acute kidney injury as demonstrated by widening of glomeruli space (Bowman space), tubular dilatation, numerous cellular debris in the renal tubules with tubular epithelial degeneration, and vacuolization, which were effectively protected by RES+QUR except a partial protection of the glomeruli space was observed. In addition, APAP significantly (p<0.05) modulated tissue levels of MDA, SOD, TNF-α, and IL-6, which were protected by RES+QUR. Furthermore, a significant (p<0.0001) positive correlation was observed between glomeruli space and TNF-α, (r=0.8899), IL-6 (r=0.8986), and MDA (r=0.8552), whereas glomeruli space scoring versus SOD showed negative correlation (r= - 0.7870). We conclude that resveratrol plus quercetin substantially protects against APAP-induced acute kidney injury in rats, possibly via the augmentation of antioxidants and inhibition of oxidative stress and inflammation.

La sobredosis de paracetamol (también llamado acetaminofen o APAP) causa un daño agudo en el hígado y los riñones, tanto en humanos como en modelos animales experimentales, a través de la inducción de la vía del estrés oxidativo. Intentamos determinar si los antioxidantes y los compuestos antiinflamatorios combinados, el resveratrol (RES) y la quercetina (QUR) pueden proteger contra la lesión renal inducida por una dosis tóxica de APAP en un modelo de rata de lesión renal aguda inducida por APAP. Las ratas recibieron una dosis única de APAP (2 g / kg) antes de ser sacrificadas después de 24 horas o se trataron previamente durante 7 días con dosis combinadas de RES (30 mg / kg) y QUR (50 mg / kg), antes de ser tratadas, se administró una dosis única de APAP y luego fueron sacrificadas 24 horas después de la ingestión. Los tejidos renales recolectados se tiñeron con H-E y fueron observados a través de microscopía óptica. Las muestras de tejido se analizaron para (i) biomarcadores de estrés oxidativo y antioxidante, malondialdehído (MDA) y superóxido dismutasa (SOD); y (ii) biomarcadores de inflamación, factor de necrosis tumoral alfa (TNF-α) e interleucina-6 (IL-6). Las imágenes teñidas con H & E mostraron que la sobredosis de APAP indujo daño renal agudo como lo demuestra la ampliación del espacio glomerular, la dilatación tubular, numerosos desechos celulares en los túbulos renales con degeneración epitelial tubular y la vacuolización, que se protegieron eficazmente con RES + QUR Se observó una protección parcial del espacio glomerular. Además, APAP modificó significativamente (p <0.05) los niveles tisulares de MDA, SOD, TNF-α e IL-6, que estaban protegidos por RES + QUR. Además, se observó una correlación positiva significativa (p <0,0001) entre el espacio glomerular y el TNF-α, (r = 0,8899), IL-6 (r = 0,8986) y MDA (r = 0,8552), mientras que la puntuación del espacio glomerular versus SOD mostró correlación negativa (r = - 0,7870). Concluimos que el resveratrol más quercetina protege sustancialmente contra la lesión renal aguda inducida por APAP en ratas, posiblemente a través del aumento de antioxidantes y la inhibición del estrés oxidativo y la inflamación.

Efficacy of curcumin on prevention of drug-induced nephrotoxicity: A review of animal studies.

Drug-induced nephrotoxicity is a frequent serious adverse effect, contributing to morbidity and increased healthcare utilization. Prevention or reversal is key. Curcumin has useful biological features that include antioxidant, anti-inflammatory, and anticancer properties. This review covers aspects of curcumin in relation to prevention of drug-induced nephrotoxicity: dosage and schedule, effect on kidney biomarkers and histological changes, and mechanisms of curcumin's protective effects. Despite success in some animal models, human studies and clinical administration of curcumin for nephroprotection remains limited due to difficulty in achieving therapeutic levels following oral administration and in determining the optimal dosing schedule. Lack of sufficient evidence from animal studies, coupled with low systemic bioavailability, continues to limit the utilization of curcumin in addressing and controlling drug-induced nephrotoxicity. Therefore, human studies are required to fully assess and validate the therapeutic potential of curcumin.

Boscartins L-O: Cembrane-type diterpenoids from the gum resin of Boswellia sacra Flueck.

Four undescribed cembrane-type diterpenoids, boscartins L-O, as well as five known compounds (1S, 3R, 11S, 12R, 7E)-1,12-epoxy-4-methylenecembr-7- ene- 3,11-diol, isoincensole oxide, incensole oxide, incensole acetate and incensole oxide acetate were isolated from the gum resin of Boswellia sacra Flueck. (Burseraceae). The structures of these compounds were elucidated by extensive 1D and 2D NMR spectroscopic and mass spectrometric analysis, as well as comparisons with known compounds. The absolute configurations of the known compound (1S, 3R, 7E, 11S, 12R)-1,12-epoxy-4-methylenecembr-7-ene-3,11-diol was unequivocally confirmed by single-crystal X-ray diffraction analysis with Cu Kα radiation. Incensole acetate exhibited significant hepatoprotective activity at 10 µM against paracetamol-induced HepG2 cell damage.

Bioactive phenolic acid-substituted glycoses and glycosides from rhizomes of Cibotium barometz.

Two rarely phenolic acid-substituted alloses (1, 2) and one new glucoside (3), as well as nine known compounds (4-12) were isolated from rhizomes of Cibotium barometz (L.) J. Sm. Structures of 1-3 were established by extensively spectroscopic analyses (NMR, MS, etc.) and acid hydrolysis. All compounds were evaluated for the hepatoprotective activities against APAP-induced HepG2 cell damage. Compounds 1, 4-7, 10 exhibited significant hepatoprotective activities, even more strongly than positive control, bicycol. In addition, compounds 1 and 9 could reduce PC12 cell death induced by serum deprivation.

Glycycoumarin protects mice against acetaminophen-induced liver injury predominantly via activating sustained autophagy.

BACKGROUND AND PURPOSE: Acetaminophen-induced acute liver injury (AILI) is the most frequent cause of acute liver failure in developed countries. Given the significant limitations associated with N-acetyl cysteine, the only antidote used to treat AILI, the development of novel therapeutic approaches that can offer a wide range of therapeutic time-windows is clearly needed. Glycycoumarin (GCM), a natural coumarin purified from liquorice, has been previously demonstrated to possess potent hepatoprotective effects. In the present study, we aimed to investigate the therapeutic potential of GCM against AILI. EXPERIMENTAL APPROACH: Acetaminophen (300 mg·kg-1 ) was administered to male C57BL/6 mice, with and without GCM. Serum transaminases, haematoxylin and eosin staining and Western blot were used to assess hepatic damage. KEY RESULTS: GCM (50 mg·kg-1 ) was highly effective against acetaminophen-induced hepatotoxicity. Moreover, GCM was superior to N-acetyl cysteine, in terms of the dosage and the therapeutic time-windows. Further mechanistic investigations revealed that the therapeutic action of GCM was not a result of inhibition of acetaminophen metabolic activation or associated with Nrf2. Instead, the protective effect of GCM appeared to be predominantly dependent on sustained activation of autophagy, which attenuated acetaminophen-induced mitochondrial oxidative stress and JNK activation. CONCLUSIONS AND IMPLICATIONS: Collectively, our results indicate that GCM alleviated acetaminophen-induced oxidative stress through activating autophagy, thereby protecting against AILI. Our findings suggest that GCM has potential as a novel therapeutic agent for treating AILI.

The effect of ondansetron on analgesic efficacy of acetaminophen after hysterectomy: A randomized double blinded placebo controlled trial.

OBJECTIVES: To determine that perioperative ondansetron reduces the analgesic efficacy of acetaminophen. DESIGN: Randomized, double-blinded study. PATIENTS: 120 patients ASA I-II who underwent abdominal hysterectomy. INTERVENTIONS: All the patients were given 1g acetaminophen at skin closure. Patients were divided into two groups; ondansetron HCl (8mg, 2ml IV) (Group I, N=60) and saline (2ml IV) (Group II, N=60) at the skin closure. MEASUREMENT: Postoperative pain scores (VAS) while resting in bed and sitting, total opioid consumption were noted. MAIN RESULTS: Patients randomized to ondansetron had significantly worse pain scores upon arrival to the recovery unit [by 1.7 (99.7% CI: 0.75, 2.59) cm] and at 1h [by 1.3 (0.5, 2.1) cm] while resting in bed. Pain scores while sitting were also significantly greater in ondansetron group at arrival in PACU by 0.6 (99.7% CI: 0.1, 1.0) cm. Thereafter, pain scores did not differ significantly. Median total opioid (tramadol) consumption was 441 [Q1, Q3: 280, 578] mg in the ondansetron group and 412 [309, 574] mg in the placebo group, P=0.95. CONCLUSIONS: Ondansetron significantly decreased the analgesic effect of acetaminophen during the initial postoperative period. Our results thus confirm that acetaminophen analgesia is partially mediated by serotonin receptors. However, the reduction was of marginal clinical importance and short-lived.

New Phenylpropanoid and Coumarin Glycosides from the Stems of Hydrangea paniculata Sieb.

A new phenylpropanoid glycoside (1), and two new coumarin glycosides (2, 3), together with two known compounds (4, 5), have been isolated from the stems of Hydrangea paniculata Sieb. Their structures have been determined by spectroscopic and chemical methods. Furthermore, compound 1 (50 µM) exhibited significant hepatoprotective activity against N-acetyl-p-aminophenol (APAP)-induced HepG2 cell damage in vitro assays.

Nrf2-mediated liver protection by esculentoside A against acetaminophen toxicity through the AMPK/Akt/GSK3ß pathway.

Acetaminophen (APAP) overdose accounts for the majority of acute liver failure cases, and oxidative stress plays a key role in its toxic effects. Esculentoside A (EsA) has anti-oxidant activities, but its therapeutic potential for APAP hepatotoxicity remains unknown. This study aimed to assess the protective effects and mechanism of EsA against APAP-induced hepatotoxicity in vitro and in vivo. In vitro, EsA treatment inhibited APAP- or H2O2-induced cytotoxicity, H2O2 and O2- production, glutathione (GSH) depletion and apoptosis dependent on nuclear factor erythroid-2-related factor 2 (Nrf2) activation in HepG2 cells. Moreover, EsA significantly increased the phosphorylation of AMP-activated protein kinase (AMPK) and serine/threonine kinase (Akt), as well as glycogen synthase kinase 3 beta (GSK-3ß) inhibitory phosphorylation at Ser9. Furthermore, an AMPK inhibitor (compound c) abolished the effects of EsA on AKT phosphorylation, GSK-3ß inactivation, Nrf2 nuclear translocation and cytoprotection. With regard to APAP-induced acute liver injury, EsA attenuated the APAP-stimulated increases in the serum ALT and AST levels, as well as centrilobular necrosis and GSH depletion in the mice. In addition, it decreased the GSSG level, GSSG-to-GSH ratio, and the phosphorylation and mitochondrial translocation of c-Jun N-terminal kinase (JNK). Further, the protective potential of EsA against mitochondrial dysfunction was exhibited not only by inhibiting Bax mitochondrial translocation and the release of mitochondrial inter-membrane proteins, such as apoptosis-inducing factor (AIF), but also by activating Nrf2/HO-1. Collectively, our findings suggest that EsA has protective potential against APAP toxicity by potentiating the Nrf2-regulated survival mechanism through the AMPK/Akt/GSK3ß pathway.

Withaferin A induces Nrf2-dependent protection against liver injury: Role of Keap1-independent mechanisms.

Small molecules of plant origin offer presumptively safe opportunities to prevent carcinogenesis, mutagenesis and other forms of toxicity in humans. However, the mechanisms of action of such plant-based agents remain largely unknown. In recent years the stress responsive transcription factor Nrf2 has been validated as a target for disease chemoprevention. Withania somnifera (WS) is a herb used in Ayurveda (an ancient form of medicine in South Asia). In the recent past, withanolides isolated from WS, such as Withaferin A (WA) have been demonstrated to be preventive and therapeutic against multiple diseases in experimental models. The goals of this study are to evaluate withanolides such as WA as well as Withania somnifera root extract as inducers of Nrf2 signaling, to probe the underlying signaling mechanism of WA and to determine whether prevention of acetaminophen (APAP)-induced hepatic toxicity in mice by WA occurs in an Nrf2-dependent manner. We observed that WA profoundly protects wild-type mice but not Nrf2-disrupted mice against APAP hepatotoxicity. WA is a potent inducer of Nrf2-dependent cytoprotective enzyme expression both in vivo and in vitro. Unexpectedly, WA induces Nrf2 signaling at least in part, in a Keap1-independent, Pten/Pi3k/Akt-dependent manner in comparison to prototypical Nrf2 inducers, sulforaphane and CDDO-Im. The identification of WA as an Nrf2 inducer that can signal through a non-canonical, Keap1-independent pathway provides an opportunity to evaluate the role of other regulatory partners of Nrf2 in the dietary and pharmacological induction of Nrf2-mediated cytoprotection.

Hepatoprotective action of various partitions of methanol extract of Bauhinia purpurea leaves against paracetamol-induced liver toxicity: involvement of the antioxidant mechanisms.

BACKGROUND: Methanol extract of Bauhinia purpurea L. (family Fabaceae) (MEBP) possesses high antioxidant and anti-inflammatory activities and recently reported to exert hepatoprotection against paracetamol (PCM)-induced liver injury in rats. In an attempt to identify the hepatoprotective bioactive compounds in MEBP, the extract was prepared in different partitions and subjected to the PCM-induced liver injury model in rats. METHODS: Dried MEBP was partitioned successively to obtain petroleum ether (PEBP), ethylacetate (EABP) and aqueous (AQBP) partitions, respectively. All partitions were subjected to in vitro antioxidant (i.e. total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH)- and superoxide-radicals scavenging assay, and oxygen radical absorbance capacity (ORAC) assay) and anti-inflammatory (i.e. lipooxygenase (LOX) and xanthine oxidase (XO) assay) analysis. The partitions, prepared in the dose range of 50, 250 and 500 mg/kg, together with a vehicle (10 % DMSO) and standard drug (200 mg/kg silymarin) were administered orally for 7 consecutive days prior to subjection to the 3 mg/kg PCM-induced liver injury model in rats. Following the hepatic injury induction, blood samples and liver were collected for the respective biochemical parameter and histopathological studies. Body weight changes and liver weight were also recorded. The partitions were also subjected to the phytochemical screening and HPLC analysis. RESULTS: Of all partitions, EABP possessed high TPC value and demonstrated remarkable antioxidant activity when assessed using the DPPH- and superoxide-radical scavenging assay, as well as ORAC assay, which was followed by AQBP and PEBP. All partitions also showed low anti-inflammatory activity via the LOX and XO pathways. In the hepatoprotective study, the effectiveness of the partitions is in the order of EABP>AQBP>PEBP, which is supported by the microscopic analysis and histopathological scoring. In the biochemical analysis, EABP also exerted the most effective effect by reducing the serum level of alanine transaminase (ALT) and aspartate transaminase (AST) at all doses tested in comparison to the other partitions. Phytochemical screening and HPLC analysis suggested the presence of: flavonoids, condensed tannins and triterpenes in EABP; flavonoids, condensed tannins and saponins in PEBP and; only saponins in AQBP. CONCLUSION: EABP demonstrates the most effective hepatoprotection against PCM-induced liver injury in rats. This observation could be attributed to its remarkable antioxidant activity and the presence of flavonoids that might probably act synergistically with other biocompounds to cause the hepatoprotection.

Chitohexaose protects against acetaminophen-induced hepatotoxicity in mice.

Acetaminophen (N-acetyl-para-aminophenol (APAP)) toxicity causes acute liver failure by inducing centrilobular hepatic damage as a consequence of mitochondrial oxidative stress. Sterile inflammation, triggered by hepatic damage, facilitates gut bacterial translocation leading to systemic inflammation; TLR4-mediated activation by LPS has been shown to have a critical role in APAP-mediated hepatotoxicity. In this study, we demonstrate significant protection mediated by chitohexaose (Chtx) in mice challenged with a lethal dose of APAP (400 mg/kg b.w.). Decreased mortality by Chtx was associated with reduced hepatic damage, increased peritoneal migration of neutrophils, decreased mRNA expression of IL-1ß as well as inhibition of inflammasome activation in liver. Further, an alternate mouse model of co-administration of a sublethal doses of APAP (200 mg/kg b.w.) and LPS (5 mg/kg b.w.) operating synergistically and mediating complete mortality was developed. Overwhelming inflammation, characterized by increased inflammatory cytokines (TNF-α, IL-1ß and so on) in liver as well as in circulation and mortality was demonstrable in this model. Also, Chtx administration mediated significant reversal of mortality in APAP+LPS co-administered mice, which was associated with reduced IL-1ß in liver and plasma cytokines in this model. In conclusion, Chtx being a small molecular weight linear carbohydrate offers promise for clinical management of liver failure associated with APAP overdose.

Hepatoprotective effect of isoquercitrin against acetaminophen-induced liver injury.

AIMS: Acetaminophen (APAP) overdose leads to severe hepatotoxicity. Isoquercitrin exhibited potential hepatoprotective effect in our previous study. The present investigation aimed to evaluate the effect of isoquercitrin against APAP induced liver injury and to explore its possible mechanism. MAIN METHODS: Mice were treated intragastrically with isoquercitrin (10, 20, or 50mg/kg) for 3days before APAP (300mg/kg) injection. After 24h from APAP treatment, the levels of serum aminotransferase, hepatic oxidative stress and nitrosative stress biomarkers were determined by commercial kits or western bolt. Activities of UDP-glucuronosyltransferases (UGTs), sulfotransferases (SULTs) and cytochrome 2E1 (CYP2E1) were evaluated using ELISA methods and standard biochemical procedures. Subsequently, the protein and mRNA levels of inflammatory factors including TNF-α, IL-1ß, IL-6 and iNOS were determined using ELISA methods, western blot or real-time PCR. The effect of isoquercitrin on APAP activated NFκB/MAPK pathway was assessed by western bolt. KEY FINDINGS: Isoquercitrin pretreatments markedly attenuated APAP induced hepatic oxidative stress, nitrosative stress and centrilobular necrosis. In addition to potent antioxidant activity, isoquercitrin was able to regulate the activities of SULTs and CYP2E1, therefore promoted APAP hepatic detoxification. The anti-inflammatory activity of isoquercitrin which involved in the amelioration of iNOS, TNF-α, IL-1ß and IL-6 production via the blockade of NF-κB and MAPK pathways also responsible for its hepatoprotective effect. SIGNIFICANCE: Our data evidenced that isoquercitrin protected liver from APAP induced injury though inhibition of oxidative stress, nitrosative stress and inflammation, as well as regulation of APAP metabolism, suggesting that isoquercitrin could be a potential hepatoprotective agent.

N-acetylcysteine amide, a promising antidote for acetaminophen toxicity.

Acetaminophen (N-acetyl-p-aminophenol, APAP) is one of the most widely used over the counter antipyretic and analgesic medications. It is safe at therapeutic doses, but its overdose can result in severe hepatotoxicity, a leading cause of drug-induced acute liver failure in the USA. Depletion of glutathione (GSH) is one of the initiating steps in APAP-induced hepatotoxicity; therefore, one strategy for restricting organ damage is to restore GSH levels by using GSH prodrugs. N-acetylcysteine (NAC), a GSH precursor, is the only currently approved antidote for an acetaminophen overdose. Unfortunately, fairly high doses and longer treatment times are required due to its poor bioavailability. In addition, oral and I.V. administration of NAC in a hospital setting are laborious and costly. Therefore, we studied the protective effects of N-acetylcysteine amide (NACA), a novel antioxidant with higher bioavailability, and compared it with NAC in APAP-induced hepatotoxicity in C57BL/6 mice. Our results showed that NACA is better than NAC at a low dose (106mg/kg) in preventing oxidative stress and protecting against APAP-induced damage. NACA significantly increased GSH levels and the GSH/GSSG ratio in the liver to 66.5% and 60.5% of the control, respectively; and it reduced the level of ALT by 30%. However, at the dose used, NAC was not effective in combating the oxidative stress induced by APAP. Thus, NACA appears to be better than NAC in reducing the oxidative stress induced by APAP. It would be of great value in the health care field to develop drugs like NACA as more effective and safer options for the prevention and therapeutic intervention in APAP-induced toxicity.

Withaferin-A Reduces Acetaminophen-Induced Liver Injury in Mice.

Withaferin-A (WA) has anti-oxidant activities however, its therapeutic potential in acetaminophen (APAP) hepatotoxicity is unknown. We performed a proof-of-concept study to assess the therapeutic potential of WA in a mouse model that mimics APAP-induced liver injury (AILI) in humans. Overnight fasted C57BL/6NTac (5-6 wk. old) male mice received 200 mg/kg APAP intraperitoneally (i.p.). After 1 h mice were treated with 40 mg/kg WA or vehicle i.p., and euthanized 4 and 16 h later; their livers were harvested and serum collected for analysis. At 4 h, compared to vehicle-treated mice, WA-treated mice had reduced serum ALT levels, hepatocyte necrosis and intrahepatic hemorrhage. All APAP-treated mice had reduced hepatic glutathione (GSH) levels however, reduction in GSH was lower in WA-treated when compared to vehicle-treated mice. Compared to vehicle-treated mice, livers from WA-treated mice had reduced APAP-induced JNK activation, mitochondrial Bax translocation, and nitrotyrosine generation. Compared to vehicle-treated mice, WA-treated mice had increased hepatic up-regulation of Nrf2, Gclc and Nqo1, and down-regulation of Il-6 and Il-1ß. The hepatoprotective effect of WA persisted at 16 h. Compared to vehicle-treated mice, WA-treated mice had reduced hepatocyte necrosis and hepatic expression of Il-6, Tnf-α and Il-1ß, increased hepatic Gclc and Nqo1 expression and GSH levels, and reduced lipid peroxidation. Finally, in AML12 hepatocytes, WA reduced H2O2-induced oxidative stress and necrosis by preventing GSH depletion. Collectively, these data show mechanisms whereby WA reduces necrotic hepatocyte injury, and demonstrate that WA has therapeutic potential in AILI.