Hepatoprotective effect of isoquercitrin against acetaminophen-induced liver injury.

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. 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-1β, 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. 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-1β and IL-6 production via the blockade of NF-κB and MAPK pathways also responsible for its hepatoprotective effect. 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.

Xie W ，Wang M ，Chen C ，Zhang X ，Melzig MF ... -  《-》

Protective effect of hyperoside against acetaminophen (APAP) induced liver injury through enhancement of APAP clearance.

Acetaminphen (APAP) overdose leads to severe hepatotoxicity. Apocynum venetum L. (A. venetum) possess potent hepatoprotective effect. Hyperoside is one of the major compounds exist in Apocynum venetum L. and might be a potential agent to protect against APAP-induce liver injury. In this study, we investigated the effect of hyperoside on APAP hepatotoxicity in mice. Mice were treated intragastrically with hyperoside (10, 50 or 100 mg/kg) for 3 days before APAP (300 mg/kg) injection. APAP alone caused severe liver injury characterized by significantly increased serum aminotransferase levels, hepatic malondialdehyde (MDA) and 3-nitrotyrosine (3-NT) formation, as well as liver superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione (GSH) depletions. Hyperoside significantly attenuated APAP-induced liver damages in a dose dependent manner, and 100 mg/kg was the most effective dose. Further study confirmed that hyperoside was able to increase activities and mRNA expressions of uridine diphoshate glucuronosyltransferases (UGTs) and sulfotransferases (SULTs), as well as to inhibit CYP2E1 activities, and thereby suppressed toxic intermediate formation and promoted APAP hepatic detoxification. Nrf-2 activation might be involved in hyperoside induced up-regulation of phase II enzymes. Collectively, our data provide evidence that hyperoside protected the liver against APAP induced injury mainly by accelerating APAP harmless metabolism, implying that hyperoside can be considered as a potential natural hepatoprotective agent.

Xie W ，Jiang Z ，Wang J ，Zhang X ，Melzig MF ... -  《-》

Distinct roles of NF-kappaB p50 in the regulation of acetaminophen-induced inflammatory mediator production and hepatotoxicity.

Dambach DM ，Durham SK ，Laskin JD ，Laskin DL ... -  《TOXICOLOGY AND APPLIED PHARMACOLOGY》

Shikonin attenuates acetaminophen-induced acute liver injury via inhibition of oxidative stress and inflammation.

Acetaminophen (APAP) overdose causes acute liver injury and leads to fatal liver damage. However, the therapies are quite limited. Shikonin is a natural product with antioxidant and anti-inflammatory activities. In the present study, the hepatoprotective effects and the underlying mechanisms of shikonin in APAP-induced hepatotoxicity in vivo and in vitro were investigated. APAP-induced acute liver injury and shikonin pretreatment models were established in vivo and in vitro, as evidenced by serum hepatic enzymes, histological changes, oxidative stress indicators and proinflammatory cytokines. The results revealed that shikonin pretreatment prevented the elevation of serum alanine transaminase (ALT), aspartate transaminase (AST) and lactate dehydrogenase (LDH) levels and markedly reduced APAP-induced histological alterations in liver tissues. Additionally, shikonin restored superoxide dismutase (SOD) expression and glutathione (GSH) content in line with the blockade of oxidative stress. The changes in gene expression involved in oxidative stress including methionine sulfoxide reductase (such as MsrA and MsrB1), heme oxygenase-1 (HO-1), SOD2 and cytochrome P450 2E1 (CYP2E1), were markedly reversed after shikonin therapy. Furthermore, shikonin markedly attenuated the APAP-induced production of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) and suppressed the expression of genes related to inflammation. In AML-12 cells, shikonin pretreatment decreased APAP-induced cytotoxicity as measured by CCK-8 assay and LDH release. The changes in gene expression involved in oxidative stress and the inflammatory response were consistent with those in mouse livers. This study indicated that shikonin attenuated APAP-induced acute liver injury via inhibiting oxidative stress and inflammatory responses in vivo and in vitro. These findings offer new insights into the potential therapy for APAP hepatotoxicity.

Guo H ，Sun J ，Li D ，Hu Y ，Yu X ，Hua H ，Jing X ，Chen F ，Jia Z ，Xu J ... -  《-》

Protective effects of α-mangostin against acetaminophen-induced acute liver injury in mice.

The purpose of this study was to evaluate the protective effects of α-mangostin against acetaminophen (APAP)-induced acute liver injury and discover its potential mechanisms in mice. Mice were continuously treated with α-mangostin (12.5 and 25 mg/kg) by intragastric administration once daily for 6 days, and injected intraperitoneally with APAP (300 mg/kg) after 1 h of α-mangostin administration on the last day. After APAP exposure for 24 h, the liver and serum were gathered to evaluate the hepatotoxicity. The results showed that α-mangostin effectively decreased the serum levels of alanine aminotransferase, aspartate transaminase, tumor necrosis factor (TNF-α), interleukin-1β and 6 (IL-1β, IL-6), and hepatic malondialdehyde level; and recovered hepatic glutathione (GSH), superoxide dismutase and catalase activities. Liver histopathological observation provided further evidence that α-mangostin pretreatment significantly inhibited APAP-induced hepatocellular necrosis, infiltration of inflammatory cell and hyperemia. According to the analysis of western-blot and RT-PCR detection, α-mangostin pretreatment validly inhibited the phosphorylation of ERK, JNK and p38 MAPK induced by APAP, which was consistent with the changes of TNF-α, IL-6 and IL-1β levels; the phosphorylation of IκBα and the translocation of NF-κBp65 were also attenuated by α-mangostin. These results provided a new mechanism for the protective effects of α-mangostin against APAP-induced acute liver injury. α-Mangostin significantly restrainted the oxidative stress induced by APAP. Moreover, the anti-inflammatory property of α-mangostin, which is mediated by the NF-κB and MAPK signaling pathways, also contributed to its hepatoprotective effect. Taken together, we believed that α-mangostin might be a potential material for drug development against drug-related hepatotoxicity.

Fu T ，Wang S ，Liu J ，Cai E ，Li H ，Li P ，Zhao Y ... -  《-》