Hepatoprotective Effect of Aqueous Extract from the Seeds of Orychophragmus violaceus against Liver Injury in Mice and HepG2 Cells.

Xiaowei Huo,Nailiang Zhu,Li Cao,Li Gao,Chenqi Liu,Xudong Xu

doi:10.3390/ijms18061197

Abstract

Orychophragmus violaceus (O. violaceus) is a kind of edible wild herb in north China and its seeds have medical potential, however, the effect of O. violaceus seeds on liver injury and the mechanism of action remains poorly understood. Thus, the purpose of the present study is to investigate the effect of O. violaceus seeds on liver injury and further explore the molecular mechanism of the beneficial effects using aqueous extract from the seeds of O. violaceus (AEOV). Mice were orally administrated with saline, AEOV, and biphenyldicarboxylate for 4 days, and were then injected subcutaneously with 0.1% carbon tetrachloride (CCl4) dissolved in corn oil. Sixteen hours later, mice were sacrificed and blood samples were collected. Then, the serum was separated and used for biochemical assay. Livers were excised and were routinely processed for histological examinations. Enzyme activities and protein levels in liver homogenates were detected using commercial kits or by western blot analysis. Additionally, the hepatoprotective effect of AEOV in vitro was evaluated using epigoitrin, the major alkaloid compound isolated from AEOV. We found that AEOV attenuated liver injury induced by CCl4 as evidenced by decreased levels of alanine aminotransferase (ALT) and aminotransferase (AST) in serum, improvement of liver histopathological changes, and substantial attenuation of oxidative stress and inflammation via regulation of nuclear factor-erythroid 2-related factor-2 (Nrf2) and nuclear factor κB (NFκB) pathways. These effects of AEOV were comparable to that of biphenyldicarboxylate which was commonly used as a hepatoprotective reference. Moreover, pretreatment of HepG2 cells with epigoitrin improved cell viability, decreased lactate dehydrogenase (LDH) and malondialdehyde (MDA) levels, increased superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity, attenuated the NFκB pathway, and elevated the Nrf2 pathway after exposure to H2O2. These results suggest that AEOV could effectively prevent CCl4-induced liver injury in mice via regulating the Nrf2 and NFκB pathways, and reveal the cytoprotective effects of epigoitrin against H2O2-induced oxidative stress in HepG2 cells.

Highlights

Liver injury, generally caused by viral hepatitis, non-alcoholic steatohepatitis, alcohol abuse, and drug intoxication [1,2], has severe consequences for metabolism, detoxification, immune response, and antimicrobial defense because the liver is involved in almost all vital biological processes
We hypothesize that approaches and drugs successfully used in controlling oxidative stress and inflammation may help protect against liver injury
The results showed that the acute liver injury induced by CCl4 treatment was significantly attenuated by AEOV treatment compared with untreated mice as determined by the reduced serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT), and less severe liver injury

Summary

Introduction

Generally caused by viral hepatitis, non-alcoholic steatohepatitis, alcohol abuse, and drug intoxication [1,2], has severe consequences for metabolism, detoxification, immune response, and antimicrobial defense because the liver is involved in almost all vital biological processes. Recent studies have suggested that the activation of nuclear factor-erythroid 2-related factor-2–antioxidant response element (Nrf2–ARE) signaling can confer protection to normal cells or tissues by preventing free radical stress [9,10,11]. Suppression of the NFκB pathway has been found to be essential for the controlling of the expression of pro-inflammatory cytokines which, otherwise, may contribute to tissue damage [12,13]. In this regard, we hypothesize that approaches and drugs successfully used in controlling oxidative stress and inflammation may help protect against liver injury

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Methods

Results