Ginkgo biloba extract inhibits the development of experimental atherosclerosis in rabbits

Abstract

Forty male mongrel rabbits were divided into 4 equal groups: (1) controls, (2) animals receiving a high-fat diet (HFD) containing cholesterol and coconut oil, (3) HFD + standardized. Ginkgo biloba extract (GB), and (4) HFD + rutin (as a well known substance it was used for comparison of pure single flavonol diglycoside activity with total extract). The experiment lasted 12 weeks. The most pronounced reduction in lipid metabolism disturbances and in the severity of plaque formation occurred after the GB had been administered. Lipid content in serum, liver homogenate and liver microsomes was depressed. HDL-cholesterol concentration was increased. Diminution of the malondialdehyde level in plasma was accompanied by an increase in the concentration of ascorbate free radicals in the liver in vitro. Testosterone concentrations in serum were normalized whilst the cytochrome P-450 content in liver microsomes was increased. Surface area of the lipid deposits at 12 weeks measured planimetrically averaged 85.5 % in HFD-fed animals vs 54.7 % in GB-treated rabbits. Quite distinct superiority of GB in antiatherosclerotic activity, as compared with rutin, was shown. These findings suggest that GB, in addition to lowering serum lipid level and possessing antioxidant properties in rabbits on an experimental diet, also affects metabolic processes in the liver and may modify lipid deposition in major arteries.