Extract from the leaf of nucifera reduced the development of atherosclerosis via inhibition of vascular smooth muscle cell proliferation and migration

Nelumbo nucifera GAERTN, a perennial aquatic plant, has been used as a medicinal herb in China and India. We have previously reported that consumption of nucifera leaf extract (NLE) reduced the development of atherosclerosis in cholesterol-fed rabbits; however, the molecular mechanisms involved were unclear. Atherosclerotic plaque is generated partly by proliferation and migration of vascular smooth muscle cells (VSMC). Herein, we demonstrated that VSMC treated with NLE-triggered apoptosis and affected the JNK and p38 Mitogen-Activated Protein Kinase (MAPK) pathways. Pre-treating VSMC with inhibitors of JNK, p38, and p53 reduced NLE-induced apoptosis. Non-cytotoxic doses of NLE also abolished secretion of MMP-2/9 and inhibited cell migration via restraining the FAK/PI 3-kinase/small G protein pathway. Histopathological examination showed that 1.0% of NLE reduced neointima formation conspicuously and inhibited smooth muscle cell proliferation and MMP-2 secretion in the blood vessel of rabbits fed with a high cholesterol diet (HCD). We also verified that the extract's total phenolic acids and the total flavonoids were approximately about 70%. In conclusion, our results shed light on the molecular mechanisms whereby the polyphenol-rich water extract of nucifera leaves could inhibit both proliferation and migration of VSMC, and it might serve as a potential anti-atherogenic agent.