Study of the hypolipidemic properties of pectin, garlic and ginseng in hypercholesterolemic rabbits

Experimental hypercholesterolemia and its modulation by some natural dietar y supplements (pectin, garlic and ginseng) and by the drug gemfibrozil were studied. Experimental hypercholesterolemia was induced by feeding rabbits a 2% cholesterol-enriched diet for 28 days. Hypercholesterolemic rabbits we re classified into five groups. One group did not receive treatments and se rved as a control hypercholesterolemic group. The other four groups were fe d the cholesterol-enriched diet in conjunction with either 10% pectin, 2% g arlic, 2% ginseng or 135 mg g(-1) b.w gemfibrozil in a daily oral dose. A n ormal group of rabbits fed a plain chow diet was also included in the study . The hypolipidemic effect of the above treatments was examined by estimati ng serum triglycerides (TG), total-, LDL- and HDL-cholesterol. Post-heparin total and hepatic lipase activities were estimated in postheparin plasma o btained 10 min after an intravenous injection of heparin (200 IU kg(-1) b.w ). In order to evaluate the antioxidant status of the rabbits, plasma malon dialdehyde (MDA) level and erythrocyte superoxide dismutase (SOD) activity were measured. After killing, aorta from all rabbits were subjected to hist opathological examination. Results of the study demonstrated that feeding t he cholesterol-enriched diet caused a significant increase in total-, LDL-, and HDL-cholesterol, plasma MDA and post-heparin total and hepatic lipase activities. On the other hand, serum TG and erythrocyte SOD were not change d. Histopathological examination revealed marked alteration in the aortic w all with the appearance of large multiple atheromatous plaques. Both garlic and pectin were successful in a significant reduction of the hypercholeste rolemia in a way comparable to gemfibrozil. Garlic was the only treatment t hat has antilipid peroxidative property. Erythrocyte SOD activity was not a ffected by hypercholesterolemia or by any of the treatments. Also, none of the treatments were able to modify the significant elevation of post-hepari n lipolytic activities associated with the hypercholesterolemia or to signi ficantly affect the serum triglycerides level. Finally, among the hyperchol esterolemic groups that received treatments, the least changes in the aorti c wall were shown in the animals of the gemfibrozil group. Slight degenerat ion was observed in the aorta of animals treated with pectin or garlic. Gin seng administration failed to exert any significant protection from the rem arkable hypercholesterolemia or atherosclerosis associated with the cholest erol-enriched diet. (C) 1999 The Italian Pharmacological Society.