Protective effects ofCoptis chinensisinflorescence extract and linarin against carbon tetrachloride-induced damage in HepG2 cells through the MAPK/Keap1-Nrf2 pathway

Abstract

Coptis chinensis inflorescence is traditionally used as tea and has been popular in the local market. C. chinensis inflorescence extract (CE) exhibits protective effects against carbon tetrachloride (CCl4)-induced damage, but the underlying mechanism remains unclear. The main chemicals of CE were detected, purified, and identified in this study. CE and linarin could reverse changes in cell viability, decrease alanine aminotransferase and aspartate transaminase levels, and reduce reactive oxygen species (ROS) generation induced by CCl4 in HepG2 cells. CE and linarin could also phosphorylate mitogen-activated protein kinases (MAPKs) and up-regulate Kelth-like ECH-associated protein (Keap1). The pathways of MAPKs and Keap1 lead to the separation of Keap1 and nuclear factor (erythroid-derived 2)-like 2 (Nrf2). Free Nrf2 transferred to the nucleus and enhanced the expression of phase II detoxification enzymes. This study provides a scientific basis for the use of C. chinensis inflorescence, which exhibits a hepatoprotective function, as a supplement in the food industry.

Isoflavone biochanin A, a novel nuclear factor erythroid 2‐related factor 2 (Nrf2)‐antioxidant response element activator, protects against oxidative damage in HepG2 cells

“…In our study, molecular docking results provide evidence that BCA exhibits the potential to disrupt Keap1–Nrf2 PPI by interacting with three representative amino acid residues in Keap1 protein (Figure a–d), including Arg 415, Ser 508, Asn 414 and Asn 382, which have all been reported to be significant for Keap1–Nrf2 PPI . In support of our docking results, we examined the protein level of Keap1 and found that the level of the BCA‐treated group was higher than that the untreated group (Figure e,f), implying that considerable free Nrf2 was dissociated from Keap1 and transferred into the cell nucleus, which has also been reported in a previous study . We can thus speculate that BCA, occupying the binding sites of Nrf2 in Keap1 protein, at least partly facilitates the release and nuclear translocation of Nrf2.…”

“…32 In support of our docking results, we examined the protein level of Keap1 and found that the level of the BCA-treated group was higher than that the untreated group (Figure 6e,f), implying that considerable free Nrf2 was dissociated from Keap1 and transferred into the cell nucleus, which has also been reported in a previous study. 37 We can thus speculate that BCA, occupying the binding sites of Nrf2 in Keap1 protein, at least partly facilitates the release and nuclear translocation of Nrf2.…”

CCl4-Induced Liver Injury Was Ameliorated by Qi-Ge Decoction through the Antioxidant Pathway

“…In the normal, unstressed state, Nrf2 remains at a low expression level due to targeted degradation by the proteasome under ubiquitination of Keap1. Once exposed to toxic prooxidant xenobiotics, such as CCl 4 , degradation of Nrf2 by the proteasome is inhibited, and it rapidly accumulates and translocates to the nucleus, initiating transcription and translation of downstream target genes, like HO-1, that promote cell detoxi cation and stress resistance [28][29][30].…”

Electrostatic field–induced tip‐electrospray ionization mass spectrometry for direct analysis of raw food materials

“…A piece of Callosobruchus chinensis (triangle, 10 mg), which is one of sources for preparation of functional foods and herbal medicines, was directly analyzed when 2.0 μL of methanol with 0.1% formic acid was added on the tip‐end of dry tissue of C. chinensis , and the high voltage was applied on the electrode in positive ion detection mode. Three peaks of alkaloids such as coptisine ( m/z 320), berberine ( m/z 336), and palmatine ( m/z 352) were clearly observed (Figure A), which are good agreement with our previous results on direct analysis of dry C. chinensis .…”