Abstract: Objective: Our aim was to study the effect and underlying mechanism of mulberry leaf alkaloids on the improvement of liver injury induced by a high-fat diet in mice for the purpose of providing a basis for the reasonable use of mulberry leaves. Methods: Mice were fed with a high-fat diet and administered by gavage with three doses of mulberry leaf alkaloids for 16 weeks. After 4, 8, 12 and 16 weeks of administration, liver index and the levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity in plasma were detected, histopathological characteristics of liver tissue were observed by hematoxylin and eosin staining and the expression of tumor necrosis factor-α (TNF-α), interleukin (IL)-10, Bax and Bcl-2 mRNA in liver tissue was also detected by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). Results: Compared with the high-fat diet control group, liver index and plasma ALT and AST activity were decreased significantly (P < 0.05), lipid deposition and steatosis in the liver were ameliorated, the mRNA expression levels of IL-10 and Bcl-2 were increased significantly (P < 0.05), and the mRNA expression levels of TNF-α and Bax were decreased significantly by administration of the alkaloids in a dose- and time-dependent manner (P < 0.05). The indexes altered by liver injury returned to normal after administration of the alkaloids at a dose of 200 mg/kg mb for 16 weeks. Conclusion: Mulberry leaf alkaloids significantly improve high-fat-induced liver injury in mice and its mechanism may be related to the regulated mRNA expression of TNF-α, IL-10, Bcl-2 and Bax.

Key words: mulberry leaf alkaloids, high-fat diet, liver injury, inflammatory factor, apoptotic factor