Mechanism of Bakuchiol-Induced Liver Injury in Mice by Transcriptomic, Proteomic, and Metabolomic Analyses

Ethnopharmacological relevance: Psoralea corylifolia L., i.e., Fructus Psoraleae (FP), a famous herbal, treats kidney- and spleen-related yang deficiencies, vitiligo, bone fracture, osteoporosis, and other conditions, refers to the ripe dried seeds of Psoralea corylifolia L. eguminosae). Existing research has confirmed that FP, results in hepatotoxicity. In our previous research, the main toxic components in FP were analyzed, and Bakuchiol (Bak) was indicated as one of these components. However, the exact underlying mechanism of how toxic components contained in FP react remains unclear.The aim of the study ：To analyze the mechanism of Bakuchiol-induced liver injury in mice by transcriptomic, proteomic, and metabolomic, providing insights into improved safety assessment of oral administration of FP.Materials and methods : In this study, toxicity was evaluated initially in ICR mice to confirm the hepatotoxicity of Bak. Subsequently, the transcription of genes, the up-regulated expression of proteins and changes of metabolite spectrum in a biological system in accordance with system pharmacology and multi-omics profiling strategy were investigated to reveal its toxic mechanism.Results: Results show that Bak-induced hepatotoxicity in our experiment was primarily manifested as hepatocyte hypertrophy. The mice administrated with Bak for 4 weeks exhibited significantly increased liver weight, liver/body weight ratio, and liver/brain weight ratio. To be specific, the liver/brain weight ratio was increased by 17.66%. The significant apoptosis of hepatocytes and hollow atrophy of nuclei were indicated by the TUNEL assay on the hepatotoxicity of Bak in mice. The mice administrated with Bak for 4 weeks showed significant apoptosis of hepatocytes, and the stained nucleus was hollow. In general, the pathways associated with Bak-induced hepatotoxicity were associated with bile secretion, primary bile acid synthesis, fatty acid biosynthesis, PPAR signaling pathway, fatty acid metabolism, and biosynthesis of unsaturated fatty acids. Moreover, 19 differentially expressed genes and proteins significantly associated with the above lipid metabolic process were screened, which were significantly associated with lipid metabolism. Next, 18 different metabolites associated with lipid metabolism were selected, which were primarily concentrated in glycerophospholipids, fatty acids, and bile acids. Seven pathways obtained through pathway enrichment were significantly associated with lipid metabolism disorder, well consistent with the previous gene and protein analysis results. Conclusion : The results analyzed and screened using multi-omics displayed consistent trends with those obtained in the hepatocyte phenotype that was tested by organ weights, relative organ weights, histopathological changes, and TUNEL assay. The study initially employed system pharmacology and 3-omics profiling strategy to propose Bak-induced liver injury in mice and elucidate the mechanism, so as to provide insights into improved safety assessment of oral administration of FP.Keywords: Hepatotoxicity, Bakuchiol, multi-omics analysis, lipid metabolism, Mechanism