OBJECTIVE To explore the mechanism of Shugan Yipi granules(sugar-free type) against nonalcoholic fatty liver disease(NAFLD) based on systematic pharmacology, clinical research and in vitro experiments.

METHODS  The levels of liver attenuation index, free fatty acid and lipids in 23 patients with NAFLD were tested. Plasma metabolomics was used to detect the composition and differential metabolites of patients. Databases such as TCMSP and GeneCards were used to screen drug components and disease targets. The protein-protein interaction(PPI) network screened core targets, and the main active components were screened according to the degree values of each node in the drug-component-target-pathway-disease network. AutoDockTools performs molecular docking between the core target and the main active ingredients. Based on the results of network pharmacology and metabolic analysis, quercetin and kaempferol, the main active components of Shugan Yipi granules(sugar-free type), were selected for preliminary cell verification experiments.

RESULTS  Network pharmacology prediction results showed that the main active components of Shugan Yigan granules(sugar-free type) included 60 types such as quercetin and kaempferol, and the core target was significantly enriched in the PI3K-AKT signaling pathway. The clinical effect of Shugan Yipi granules(sugar-free type) showed that it could significantly improve liver hardness and fat decay, and significantly reduce the levels of free fatty acids and lipids in patients. In plasma metabolomics analysis, quercetin and kaempferol were significantly upregulated by differential metabolites. The in vitro validation experiments showed that quercetin and kaempferol could effectively inhibit intracellular fatty acid uptake, reduce lipid deposition and triglyceride(TG) content in NAFLD cell models, and up-regulate the expression of p-PI3K/AKT and p-AKT/AKT in the PI3K-AKT signaling pathway.

CONCLUSION  Shugan Yipi granules(sugar-free type) can improve liver lipid metabolism in patients with NAFLD. Quercetin and kaempferol are the key active ingredients of Shugan Yipi granules(sugar-free type) in the prevention and treatment of NAFLD, and the PI3K-AKT signaling pathway is the main signaling pathway predicted. Quercetin and kaempferol can inhibit fatty acid uptake in HepG2 cells induced by free fatty acids, reduce lipid accumulation and TG content in NAFLD cell model, and may alleviate NAFLD by promoting protein phosphorylation in PI3K-AKT signaling pathway.