Hypocholesterolemic effects of Curcuma longa L. with Nelumbo nucifera leaf in an in vitro model and a high cholesterol diet-induced hypercholesterolemic mouse model

Hypercholesterolemia is one of the well-established risk factors for cardiovascular mortality and morbidity in coronary heart disease. The present study was designed to investigate the effects of different types of extracts (aqueous, 20%-, and 80% ethanol) of Nelumbo nucifera leaf (NL) and Curcuma Longa L. (CL) on hypercholesterolemia in in vitro and in vivo models. Our results in in vitro experiments showed that treatment with various extracts of both NL and CL dose-dependently inhibited lipid accumulation and total cholesterol content. The 20% ethanol extract of NL (NL20E) and the aqueous extract of CL (CLW) showed the highest activity. The in vivo experimental group was fed a high cholesterol diet (HCD) with oral administration of NL20E, CLW, or a mixture of NL20E with CLW (NC; mixed equal ratio) for 8 weeks. The oral administration of NL20E, CLW, and NC (100 or 300 mg/kg/day) resulted in the suppression of the levels of serum total cholesterol (TC), low-density lipoprotein (LDL)-cholesterol, liver lipid level, glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), atherogenic index (AI), cardiac risk factor (CRF), cholesteryl ester transfer protein (CETP), HMG-CoA reductase, and thiobarbituric acid-reactive substances (TBARS). Similarly, the NL20E, CLW, and NC extracts elevated high-density lipoprotein (HDL) cholesterol levels and lecithin cholesterol acyltransferase (LCAT) activity. Furthermore, NC showed a remarkable hypocholesterolemic effect by decreasing the levels of hepatic TC, AI, LDL cholesterol, HMG-CoA reductase, and CRE and by increasing the levels of HDL cholesterol. Thus, the results of this study indicate that the NC has combined hypocholesterolemic effects that block lipid accumulation, thus preventing hypercholesterolemia.