Metabolic profiling of emodin drug-induced liver injury and silybin treatment in rats using ultra-performance liquid chromatography-quadrupole-time-of-flight-mass spectrometry: A metabolomic and mechanistic approach

Silybin, an active component in the plant Silybum marianum (L.) Gaertn., is commonly used to protect against liver disease. We investigated silybin's protective potential in rat liver against emodin-induced liver injury 4 weeks. It was found that aspartate aminotransferase and direct bilirubin serum biomarkers for liver toxicity significantly increased, and liver histopathology revealed cholestasis and necrosis in rats administered emodin alone, whereas aspartate aminotransferase and total bile acid levels in rats administered emodin and silybin simultaneously were changed compared to rats administered emodin alone. Liver mRNA and protein levels of Cyp7a1-which plays roles in cholesterol metabolism and bile acid synthesis-and Abcb11 (Bsep)-which facilitates bile salt secretion in hepatocyte canaliculi-were significantly altered with emodin, whereas cotreatment with silybin attenuated emodin's adverse effect. Metabolomic analysis using ultra-performance liquid chromatography-quadrupole-time-of-flight-mass spectrometry determined eight potential metabolite biomarkers in serum, urine, and liver tissue. Network analysis was conducted to conceptualize the interplay of genes, metabolites, and metabolic pathways for cholesterol metabolism and bile acid synthesis for liver injury. Overall, rats administered only emodin were shown to be a sound model to investigate fat-associated drug-induced hepatoxicity or liver injury and cotreatment of emodin with silybin prevents fatty liver injury. This metabolomic study revealed that emodin-induced fatty liver injury disrupted bile acid synthesis, vitamin B-6, and glycerophospholipid metabolism pathways and that silybin ameliorates liver injury on these compromised pathways.