Ocimum basilicum ethanolic extract decreases cholesterol synthesis and lipid accumulation in human macrophages

Macrophage lipid accumulation induced by low density lipoproteins (LDL) plays a pivotal role in atherosclerotic plaque development. Previous work showed that Ocimum basilicum extract, used as hypocholesterolemic agent by traditional medicine ill Morocco, has hypolipidemic activity in rat acute hyperlipimidemia. This study investigated the effects of ethanolic extract of O. basilicum on lipid accumulation in human macrophages. As modification of LDL increase atherogenicity of the particles we evaluated the effects of the extract on LDL oxidation. The extract Caused a dose-related increase of LDL-resistance to CU2+ -induced oxidation. Furthermore. at the dose of 60 mu g/ml, significantly decreases the accumulation of macrophage lipid droplets induced by rnodified LDL evaluated as by red-oil staining. Cholesterol esterification and triacylglycerol synthesis in the cells were not affected. Macrophage treatment with 60 mu g/ml, but not 20 mu g/ml, of the extract reduced newly synthesized unesterified cholesterol by about 60% and decreased scavenger receptors activity by about 20-30%, evaluated by the internalization of cholesterol carried by [H-3]CE-aggregated-LDL. The results suggest that O. basilicum ethanolic extract has the capability to reduce foam eel I formation through the reduction of cholesterol synthesis and the rnodulation of the activity of surface scavenger receptors. (C) 2008 Elsevier B.V All rights reserved.