Monotropein resists atherosclerosis by reducing inflammation, oxidative stress, and abnormal proliferation and migration of vascular smooth muscle cells.

Monotropein is a compound classified into iridoid which is found in herbaceous plants Morindae officinalis. It possesses anti-inflammatory, antioxidant, and anti-osteoarthritic activities. Previous study indicates that monotropein may have the potential to combat cardiovascular disease, although the related mechanism remains unclear. In this study, we constructed the model of atherosclerosis by oxidized low density lipoprotein-induced vascular smooth muscle cells and LDLR^-/- mice given high-fat diet to investigate the effects of monotropein on atherosclerosis. Our results showed that monotropein treatment significantly reduced the area of atherosclerotic plaques and necrotic cores in mice, inhibited the proliferation and migration of vascular smooth muscle cells, and reduced inflammatory responses and oxidative stress, which in turn alleviated atherosclerosis. In addition, we found that monotropein reduced the expression levels of P-NF-κB and P-AP-1. In conclusion, our data suggest that monotropein inhibited the proliferation and migration of vascular smooth muscle cells by mediating the activity of NF-κB, AP-1, reducing the level of inflammation and oxidative stress, and thus resisting the development of atherosclerosis. These findings demonstrate the efficacious therapeutic impact of monotropein on atherosclerosis and elucidate its specific target.