Induction of Mkp-1 and Nuclear Translocation of Nrf2 by Limonoids from Khaya grandifoliola C.DC Protect L-02 Hepatocytes against Acetaminophen-Induced Hepatotoxicity

Abstract

Drug-induced liver injury (DILI) is a major clinical problem where natural compounds hold promise for its abrogation. Khaya grandifoliola (Meliaceae) is used in Cameroonian traditional medicine for the treatment of liver related diseases and has been studied for its hepatoprotective properties. Till date, reports showing the hepatoprotective molecular mechanism of the plant are lacking. The aim of this study was therefore to identify compounds from the plant bearing hepatoprotective activity and the related molecular mechanism by assessing their effects against acetaminophen (APAP)-induced hepatotoxicity in normal human liver L-02 cells line. The cells were exposed to APAP (10 mM) or co-treated with phytochemical compounds (40 μM) over a period of 36 h and, biochemical and molecular parameters assessed. Three known limonoids namely 17-epi-methyl-6-hydroxylangolensate, 7-deacetoxy-7-oxogedunin and deacetoxy-7R-hydroxygedunin were identified. The results of cells viability and membrane integrity, reactive oxygen species generation and lipid membrane peroxidation assays, cellular glutathione content determination as well as expression of cytochrome P450 2E1 demonstrated the protective action of the limonoids. Immunoblotting analysis revealed that limonoids inhibited APAP-induced c-Jun N-terminal Kinase phosphorylation (p-JNK), mitochondrial translocation of p-JNK and Bcl2-associated X Protein, and the release of Apoptosis-inducing Factor into the cytosol. Interestingly, limonoids increased the expression of Mitogen-activated Protein Kinase Phosphatase (Mkp)-1, an endogenous inhibitor of JNK phosphorylation and, induced the nuclear translocation of Nuclear Factor Erythroid 2-related Factor-2 (Nrf2) and decreased the expression of Kelch-like ECH-associated Protein-1. The limonoids also reversed the APAP-induced decreased mRNA levels of Catalase, Superoxide Dismutase-1, Glutathione-S-Transferase and Methionine Adenosyltransferase-1A. The obtained results suggest that the isolated limonoids protect L-02 hepatocytes against APAP-induced hepatotoxicity mainly through increase expression of Mkp-1 and nuclear translocation of Nrf2. Thus, these compounds are in part responsible of the hepatoprotective activity of K. grandifoliola and further analysis including in vivo and toxicological studies are needed to select the most potent compound that may be useful as therapeutic agents against DILI.

Advanced preclinical models for evaluation of drug-induced liver injury – consensus statement by the European Drug-Induced Liver Injury Network [PRO-EURO-DILI-NET]

“…An additional player that contributes to sustained JNK phosphorylation in APAP hepatotoxicity is through impaired MAPK phosphatases (Mkp). Mkp deficiency in mice has been shown to exacerbate APAP-induced liver injury along with sustained JNK activation, while Mkp activation prevents JNK activation and subsequent APAP hepatotoxicity [39,40].…”

Adding hepatoprotective plants to beverage water: an alternative to conventional drugs for broiler production

“…The difference between individuals in each lot could be due to agerelated physiological changes (Slominski, 2011;Kouam et al, 2017).…”

“…Pro and prebiotics, enzymes, acidifiers, phytogenic and herbal products have been investigated as alternatives to antibiotic in animal feed (Yang et al, 2009). Many beneficial effects for bioactive herbal derivatives and essential oils (EO's) has been reported including increase in digestive enzymes secretion and activities, improving gut health by selectively growth stimulating effects on useful bacterial species and inhibition of pathogens and improving immune system status (Jang et al, 2007;Bolukbasi et al, 2008;Rahimi et al, 2011;Kouam et al, 2017). Therefore, EO of herbs could be considered as a potential replacement for antibiotic growth promoters.…”

Inhibition of CYP2E1 and activation of Nrf2 signaling pathways by a fraction from Entada africana alleviate carbon tetrachloride-induced hepatotoxicity

“…Finally, the most active sub-fractions along with EaF10 were analyzed by HPLC-ACN (Acetonitrile)-Standard-Method and their phytochemical components detected at 254nm as described by Kouam et al. [ 22 ].…”

“…Thirteen g of EaF10 (the most active fraction) were obtained, and 10 g of this fraction were further fractionated over silica gel 60 (particle size 40-63μm) column chromatography (column: d x h ¼ 3.5 Â 65 cm) coupled to thin layer chromatography (TLC) and seven sub-fractions namely EaF10sf1 (55mg), EaF10sf2 (47mg); EaF10sf3 (19mg); EaF10sf4 (51mg), EaF10sf5 (66mg), EaF10sf6 (31mg) and EaF10sf7 (58mg) were obtained and evaluated for their hepatoprotective activity in vitro. Finally, the most active sub-fractions along with EaF10 were analyzed by HPLC-ACN (Acetonitrile)-Standard-Method and their phytochemical components detected at 254nm as described by Kouam et al [22].…”