Anti-inflammatory effects of Viola yedoensis and the application of cell extraction for investigating bioactive constituents in RAW 264.7 cells

Viola yedoensis (VY, Violaceae) is a popular medicinal herb used in traditional East-Asian medicine for the treatment of inflammation-related diseases including swelling, sores, boils, furuncles, carbuncles, snakebites, and acute and chronic hepatitis [1]. However, the anti-inflammatory activities and its inhibitory mechanisms of VY have not been demonstrated. In this study, we investigated the anti-inflammatory effects of VY ethanol extract (VYE) on macrophages and attempted to identify the bioactive components of VYE. We assessed the effects of VYE on secretion of nitric oxide (NO) and inflammatory cytokines including tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β. In addition, we explored the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, and changes in heme oxygenase (HO)-1, nuclear factor (NF)-κB, and mitogen-activated protein kinase (MAPK) signaling pathways in lipopolysaccharide (LPS)-stimulated murine macrophages. In addition, a rapid and useful approach to identify potential bioactive components in VYE with anti-inflammatory effects was developed using murine macrophage cell extraction coupled with high-performance liquid chromatography tandem mass spectrometry (LC-MS). We found that VYE exerted anti-inflammatory activity by inhibiting the production of key inflammation mediators and related products, as well as suppression of HO-1, NF-κB, and MAPK signaling pathway activation in RAW 264.7 cells. In addition, we identified two compounds in VYE via the cell extraction. Our results revealed that VYE exerts anti-inflammatory activities and its detailed inhibitory mechanism in LPS-stimulated macrophages. Furthermore, we identified bioactive components of VYE.

[1] Editorial Committee of Chinese Pharmacopoeia. Pharmacopoeia of the People's Republic of China, 2010 edition. Beijing: China Medical Science and Technology Press; 2010: 317