Vitisin A suppresses LPS-induced NO production by inhibiting ERK, p38, and NF-kappaB activation in RAW 264.7 cells.

Vitisin A, a resveratrol tetramer isolated from Vitis vinifera roots, exhibits antioxidative, anticancer, antiapoptotic, and anti-inflammatory effects. It also inhibits nitric oxide (NO) production. Here, we examined the mechanism by which vitisin A inhibits NO production in lipopolysaccharide (LPS)-induced RAW 264.7 macrophage cells. Vitisin A dose dependently inhibited LPS-induced NO production and inducible NO synthase (iNOS) expression. In contrast, the production of proinflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) was not altered by vitisin A. To investigate the signaling pathway for NO inhibition by vitisin A, we examined nuclear factor-kappaB (NF-kappaB) activation in the mitogen-activated protein kinase (MAPK) pathway, an inflammation-induced signal pathway in RAW 264.7 cells. Vitisin A inhibited LPS-induced extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 phosphorylation and suppressed LPS-induced NF-kappaB activation in RAW 264.7 cells. This suggests that vitisin A decreased NO production via downregulation of ERK1/2 and p38 and the NF-kappaB signal pathway in RAW 264.7 cells.