Ethanolic Extract of Garcinia kola Stem Bark Inhibits LDL-Uptake and LPS-Induced Anxa-1 and ICAM-1 Expression in Human Umbilical Vein Endothelial Cells (HUVECS)

Abstract

The endothelial cells’ dysfunction linked to the development of atherosclerosis plays an important role in the regulation of inflammatory responses. Previous studies demonstrated the antiatherogenic effects of Garcinia kola seed extracts based on their lipid lowering effects. Our recent studies showed the in vitro antioxidant and anti-inflammatory activities of the ethanolic extract of Garcinia kola stem barks (EE). For more insight on the antiatherogenic effect of EE, we investigated its activity on some key points of the atherosclerosis process. The cytotoxicity of EE as well as its effects on LDL-uptake, LPS-induced InterCellular Adhesion Molecule (ICAM-1) and Annexin-1 (Anxa-1) expression and LPS-induced DNA damage were evaluated in Human Umbilical Vein Endothelial Cells (HUVECs). EE significantly (p<0.0001) increased the cell viability in both naive and LPS-treated HUVECs. At the concentrations of 50 and 100 µg/ml, EE significantly reduced LDL-uptake by endothelial cells stimulated with LPS. The immunohistochemistry results showed a significant (p<0.01) decrease in the ICAM-1 expression at the EE concentration of 250 µg/ml. EE also showed a significant (p<0.0001) concentration-dependent reduction of Annexin-1 expression in LPS-treated HUVECs. Besides, EE exhibited significant inhibition on LPS-induced genotoxicity marked by a decrease in tail DNA expression (p<0.0001) and tail movement expression (p<0.001) for the concentrations of 50 and 100 µg/ml. These findings showed that EE may mitigate the atherogenic process by reducing LDL-uptake and the expression of adhesion molecules. Thus, the EE of Garcinia kola turns out to be a potential candidate for the treatment of atherosclerosis with a lower risk of toxicity.
 Keywords: Garcinia kola, LDL-uptake, LPS-induced inflammation, comet assay.