Liensinine Prevents Vascular Inflammation by Attenuating Inflammatory Mediators and Modulating VSMC Function

Liensinine is a bisbenzylisoquinoline alkaloid found in various parts of the lotus (Nelumbo nucifera Gaertn.) including seeds. In this study, we explored the preventive activity of liensinine on vascular inflammation via attenuation of inflammatory mediators in macrophage and targeting the proliferation and migration of human vascular smooth muscle cells (VSMC). Anti-oxidative activity was evaluated by using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay method and measuring the peroxidation of serum lipid. Inflammatory markers were studied by evaluating the release of nitric oxide (NO) and the protein levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX-2) in macrophage cells (RAW264.7) and interleukin (IL)-6 production in VSMC. Similarly, anti-proliferative activity in VSMC was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The enzymatic activity of matrix metalloproteinase (MMP)-9 in VSMC was evaluated by gelatin zymography. Liensinine possesses significant anti-oxidative activity as revealed by the DPPH assay and inhibition of serum lipid peroxidation. Likewise, liensinine decreased NO generation in RAW 264.7 cells. In VSMC, liensinine suppressed platelet-derived growth factor stimulated proliferation and tumor necrosis factor-α (TNF-α) induced MMP-9 enzymatic activity as well as IL-6 expression. Our results revealed the potential preventive effect of liensinine on vascular inflammation, suggesting it as a promising compound for the prevention of vascular inflammation.