Evaluation Of Hepatoprotective Activity And Mechanism Of Some Iridoids

The liver is an important organ of human body,which is vulnerable to invasion from all sides.Drug-induced liver injury has become a major cause of liver diseases,among which acetaminophen(APAP)is the representative drug.APAP is a common antipyretic and analgesic drug,which often causes burden or even liver injury to the liver intentionally or unintentionally.The existing drug N-acetylcysteine(NAC)for treating liver injury induced by APAP has a narrow therapeutic window and many side effects,so it is necessary to find a new substitute drug.Swertiamarin(STM)belongs to iridoid compounds,and its pharmacological activities are extensive,but the effect of STM on APAP-induced hepatotoxicity has not been reported so far.Thermal conversion products(HTPS)are the products produced by STM in the preparation process.Previous research by our research group found that HTPS may have potential liver protection effect,and some iridoid compounds were isolated from it.In this paper,the protective effect and mechanism of STM and HTPS on APAP-induced liver injury were explored through in vitro and in vivo experiments.The activity of several iridoid compounds isolated and purified from HTPS was screened to clarify the material basis of HTPS.In vitro experiment,L-O2 cells were given APAP(10 m M)to establish an in vitro hepatotoxicity model,and normal control group,positive group and different doses of STM and HTPS were set up.The effects of STM and HTPS on the viability and apoptosis of L-O2 cells induced by APAP were analyzed by CCK-8 method and flow cytometry.The levels of oxidative stress and inflammation were detected by biochemical kit,and the effects of STM and HTPS on APAP-induced hepatotoxicity model in vitro were evaluated.After preventive administration of different doses of STM and HTPS for 7 days,Kunming mice were given APAP(200 mg/kg)to establish an acute hepatotoxicity model in vivo.To investigate the effects of STM and HTPS on liver injury induced by APAP in mice.Hematoxylin-eosin staining was used to evaluate the pathological changes of liver tissue.The levels of oxidative stress and inflammation were detected by biochemical kit,and the expressions of Nrf-2 and NF-κB were analyzed by western bloting.L-O2 cells and Hep G-2 cells were given APAP(10 m M)in vitro to establish the hepatotoxicity model in vitro.Different monomers were given,and serum biochemical indexes were analyzed by CCK-8 method to screen the protective activity of iridoid compounds isolated from HTPS on APAP-induced liver injury model in vitro.The results showed that STM and HTPS reduced the apoptosis of L-O2 cells induced by APAP.Both in vitro and in vivo experiments showed that STM and HTPS significantly reduced the levels of ALT,AST and LDH,and inhibited the levels of inflammatory factors IL-6,TNF-α and IL-1β induced by APAP.Western bloting showed that STM and HTPS activated the expression of Nrf-2pathway-related proteins and inhibited the activation of NF-κB pathway.The screening results of hepatoprotective activities of several iridoid compounds isolated from HTPS showed that Swertiamarin B,Swerimilegenin E and Swertianone E increased the cell viability induced by APAP,and decreased the indexes of liver injury ALT and AST.