Hepatoprotective effect of total flavonoids from Carthamus tinctorius L. leaves against carbon tetrachloride-induced chronic liver injury in mice

Carthamus tinctorius L. leaves, a waste product after Carthami flos production, are rich in flavonoids. Total flavonoids from C. tinctorius L. leaves (TFCTLL) exhibited the protective effect on acute liver injury in mice in previous studies. The aim of the present study was to evaluate the hepatoprotective effect of TFCTLL on chronic liver injury (CLI) and investigate the underlying mechanism. The chemical components of TFCTLL were identified by UPLC-Q-TOF/MS, and their migration into blood was evaluated. The protective effect of TFCTLL on CLI was evaluated by antioxidative and anti-inflammatory experiments in vitro, network pharmacology and a carbon tetrachloride (CCl4)-induced CLI mouse model. We indentified 18 chemical components in the TFCTLL samples and 4 components in plasma. TFCTLL showed significant anti-inflammatory activity and antioxidant capacity in vitro and in vivo. TFCTLL administration prominently improved the liver function and structure, decreased the mRNA expression levels of TLR2, TLR3, TLR4, NF-κB p65, IRF3, AKT1, TRIF, PI3K, MyD88, IL-1β and TNF-α and inhibited the protein expression and nuclear translocation of NF-κB p65 in mice with CLI. The molecular docking results showed that components in plasma had high binding affinity for the targets TLR4, PI3K and AKT1. Therefore, TFCTLL has a protective effect against CCl4-induced CLI, and the underlying mechanisms may be related to antioxidation, anti-inflammation and modulation of the TLRs/NF-κB and PI3K/AKT pathways.