Inhibitory effects of natural plant extracts on ICAM-1/LFA-1 mediated adhesion of HL-60 cells

Atherosclerosis is a progressive disease characterized by the accumulation of lipids and fibrous elements in the arteries. Monocytes/macrophages are involved in many aspects of the development of atherosclerotic plaques. It is known that the intercellular adhesion molecule-1 (ICAM-1) expressed preferentially on endothelial cells of atherosclerotic plaque, promotes local adhesion and transendothelial migration of monocytes, neutrophils, and lymphocytes. Using the human promyelocytic leukemia HL-60 cell line, we investigated the inhibitory effects of methanol extracts of 175 natural plants on ICAM-1/LFA-1 mediated cell adhesion. Eight kinds of methanol extracts of tested plants inhibited PMA-induced homotypic aggregation of HL-60 cells without cytotoxicity at the concentration of 6.25 μg/ml. They were divided two fractions of CHCl3 and H2O to use solvent partition. Among them, CHCl3 extracts (1.0 μg/ml) of Saururus chinensis and Chloranthus japonicus significantly inhibited aggregation of HL-60 cells without cytotoxicity, respectively.