Effects of Allium hookeri Ethanol Extract on Foam Cell Cholesterol Efflux, Lipid Accumulation, and Inflammation

Atherosclerosis, the main cause of cardiovascular disease, is a chronic disease that causes inflammation and fat deposits called plaque to accumulate on the inner walls of arteries.The early stages of atherosclerosis are characterized by the influx of oxidized low-density lipoproteins (ox-LDL), forming cholesterol-containing foam cells.Allium hookeri has various physiological activities, such as anti-obesity, antioxidation, and anti-cancer.This study examined the inhibitory effect of A. hookeri extract on foam cell formation by co-treatment with ox-LDL and lipopolysaccharides (LPS), which mimics the development of atherosclerosis in vitro.THP-1 cells were differentiated by PMA (1 μM) for 48 h and treated in the absence or presence of A. hookeri 80% ethanol extract (AHEE) for 48 h.THP-1 macrophages were treated with ox-LDL (20 μg/mL) and LPS (500 ng/mL) for 24 h.The Oil red O confirmed that AHEE reduced lipid accumulation compared to the untreated control.AHEE reduced the expression of scavenger receptors, specific receptors involved in lipid uptake, and significantly upregulated the expression of ATP binding cassette subfamily A member 1, liver-X-receptor ɑ, and peroxisome proliferator-activated receptor gamma, which are involved in cholesterol efflux.The combined treatment of ox-LDL and LPS increased the expression of nuclear factor-κB (NF-κB), cyclooxygenase-2, tumor necrosis factor-α and interleukin 6.However, AHEE reduced the activation of NF-κB and suppressed inflammatory cytokine expression.These results suggest that AHEE can potentially prevent and inhibit atherosclerosis.