Effects of a purified saponin mixture from alfalfa on plasma lipid metabolism in hyperlipidemic mice

Abstract

Alfalfa (Medicago sativa L.) is a genus distributed widely throughout the world and considered as the richest land source of nature products. In this study, we obtained a purified saponin mixture (PSM) through a simple, re-peatable and controllable separation method from alfalfa. The compounds of the saponin mixture were identified as Azukisaponin V and Soyasaponin I, which was determined as 79.26 and 20.74% respectively by HPLC-evaporative light scattering detection (ELSD) method. The effects of PSM on plasma lipid metabolism were studied in hyper-lipidemic mice induced by Triton WR-1339. Results showed that PSM could significantly inhibit the increase of total cholesterol (TC), triacylglycerol (TG) and low density lipoprotein cholesterol (LDL-C) levels, and the decrease of plasma high density lipoprotein cholesterol (HDL-C) level in plasma of hyperlipidemic mice induced by Triton WR-1339. Further study demonstrated that PSM not only enhanced the activities of lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) in liver, but also increased their mRNA levels in hyperlipidemic mice. The results above indicate that PSM from alfalfa exerts effects on plasma lipid metabolism through elevating the activity of liver lipases in hyperlipidemic mice. The obtained data would be a good contribution to the development and utilization of alfalfa in the world. © 2011 by The Pharmaceutical Society of Japan.