Lipid-lowering and antioxidant activities of Jiang-Zhi-Ning in Traditional Chinese Medicine

Abstract

Ethnopharmacological relevance: Jiang-Zhi-Ning (JZN) is composed of four Chinese herbs, i.e., Fleeceflower Root, Fructus Crataegi, Folium Nelumbinis and Semen Cassiae. It was used to strengthen blood circulation of coronary artery, arrhythmia and hyperlipidemia.

Aim of the study: The main objective of this paper is to evaluate lipid-lowering and antioxidant activities of extract and effective fraction of JZN by using in vitro experiments on hyperlipidemic rats. Moreover, in vivo experiments on cells were performed to investigate lipid-lowering and antioxidant activities of effective fraction and active constituents of JZN.

Materials and method: Wistar rats with high fat diet-induced hyperlipidemia were used as in vitro models to study biological effects of lipid-lowering and antioxidant activities of extract and effective fraction of JZN. Serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), Coronary Index and Atherogenic Index were investigated to evaluate lipid-lowering effects of extract and effective fraction of JZN. Serum total nitric oxide synthase (NOS), nitric oxide (NO), endothelin-1 (ET-1), malondialdehyde (MDA), superoxide dismutase (SOD) and total antioxidant capacity (T-AOC) were detected to measure antioxidant effects of extract and effective fraction of JZN. Furthermore, oxidized low-density lipoprotein (Ox-LDL) injured human umbilical vein endothelial cell (HUVEC) model was employed as in vivo experiment to study lipid-lowering and antioxidant effects of effective fraction and active constituents of JZN. NO, ET-1, MDA SOD and T-AOC in HUVECs or culture media were investigated to evaluate antioxidant activity of effective fraction and active constituents of JZN. Using human hepatoma cell line Bel-7402, reverse transcription polymerase chain reaction (RT-PCR) technology was performed to investigate cholesterol metabolism effects of effective fraction and active constituents of JZN. Expressions of low density lipoprotein receptor (LDL-R), 3-hydroxy-3-methyl-HMG-coenzyme A reductase (HMG-CoAR), and cholesterol 7α-hydroxylase (CYP7A1) mRNA of the liver cells were investigated to evaluate JZN on associated receptor and enzymes of cholesterol metabolism. High-performance liquid chromatography (HPLC) and spectrophotometry were used to study the impact of effective fraction and active constituents of JZN on synthesis and translation of cholesterol during the process of metabolism by measuring inside and extracellular contents of total bile acid (TBA) of Bel-7402.

Results: Extract and effective fraction of JZN significantly reduced contents of TC, TG and LDL-C, CRI and AI in hyperlipidemic rats as well as significantly increased contents of HDL-C in the rats. Moreover, they significantly enhanced the activity of NOS and increased contents of NO. They also caused significant reductions in contents of ET-1 and MDA as well as significant increase in SOD activity and T-AOC in the hyperlipidemic rats. Several indicators were found to be concentration-dependent. As far as in vivo experiments to investigate biological activities of effective fraction and active constituents of JZN were concerned, it was found that they restored and enhanced the vitality of HUVECs with a concentration-dependent manner as well as content of NO in the culture media of HUVEC. They caused reductions in the contents of ET-1 in the culture media of HUVEC and contents of MDA in HUVECs. They also caused an increase in the vitality of SOD and T-AOC in HUVECs. Furthermore, they enhanced LDL-RmRNA expression, with a concentration-dependent manner. Low and medium concentrations of effective fraction and active constituents of JZN could inhibit expression of HMG-CoAR mRNA. High concentration counterpart could enhance expression of the HMG-CoAR mRNA. They enhanced expression of CYP7A1 mRNA in a concentration-dependent manner. Finally, they caused reductions in the contents of cholesterol in Bel-7402. They also increased intercellular content of total bile acid as well as lowered extracellular contents of TBA in the cells in a concentration-dependent manner.

Conclusion: We demonstrated for the first time lipid-lowering and antioxidant activities of extract and effective fractions as well as active constituents of JZN. Active constituents of JZN had the same biological effects with effective fraction and extract of JZN. Therefore, this study supports its ethnopharmacological use in Traditional Chinese Medicine to manage hyperlipidemia and paves a basis for establishing quality control method of Chinese medicine.