Lipid regulation effects of Polygoni Multiflori Radix, its processed products and its major substances on steatosis human liver cell line L02

Raw and processed Polygoni Multiflori Radix (PMR) are used in the prevention and treatment of non-alcoholic fatty liver disease (NAFLD), hyperlipidemia or related diseases. However, few researches compared the activities of raw and processed PMR on lipid metabolism regulation. Moreover, the active substances of Polygonum multiflorum are still not clearly elucidated. In this research, a sensitive, accurate and rapid in vitro model, steatosis hepatic L02 cell, was applied to compare the relative activities of raw and processed PMR on lipid metabolism regulation. Furthermore, the lipid regulation activities of emodin, physcion and 2,3,5,4′-tetrahydroxy-stilbene-2-O-β-d-glucoside (TSG) were evaluated. The steatosis L02 cells were obtained after cultured with 1% fat emulsion–10% fetal bovine serum (FBS)–RPMI 1640 medium for 48h. Contents of total cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C) in L02 cells are evaluated after exposure. The intracellular TG contents were increased from 16.50±1.29mmol/L to 34.40±1.36mmol/L in steatosis L02 cells, while the intracellular contents of TC were increased from 5.07±1.80mmol/L to 11.79±0.54mmol/L. Water extract of raw PMR showed much remarkable TG-regulation and TC-regulation effects than its processed products. Emodin displayed the best TG regulation activity while TSG showed the best TC regulation activity. At the same time, the exposure of emodin and physcion could reduce the LDL-C contents in steatosis L02 cells. On account of these in vitro results, raw PMR might have more satisfactory effects in clinic treatment of NAFLD or hyperlipidemia characterized by the elevation of cholesterol than processed PMR.