Hypolipidemic effect of proteoglycans isolated from sweet potato (Ipomoea batatas LAM) in hyperlipidemia rats

Effects of sweet potato proteoglycans (SPG) in rats fed high lipid diets were investigated. Serum lipid indices for SPG were evaluated. SPG had hypolipidemic effects that were correlated with dosage. There were no significant (p>0.05) differences in hypolipidemic effects between SPG varieties of different molecular weights. SPG-1 (Mw value: 508.3 kDa) significantly (p<0.05) reduced serum total cholesterol (TC), triacylglyceride (TAG), low density lipoprotein cholesterol (LDL-C), and apolipoprotein (Apo) B levels, and the arteriosclerosis index (AI), and induced serum high density lipoprotein cholesterol (HDL-C), ApoA-I, lecithin cholesterol acyltransferase (LCAT), and liver lipoprotein lipase (LPL) activities, compared with controls. The whole blood viscosity and red blood cell (RBC) membrane microviscosity were also decreased. Hypolipidemic effects were mediated via elevation of the serum HDL-C concentration by induction of LACT activity, an increased ApoA-I concentration, and a reduction in the serum lipid concentration due to regulation of LPL activity.