Anti-inflammatory effect of Rhus verniciflua stokes extract in the murine macrophage cell line, Raw264.7

Rhus verniciflua stokes (RVS) (Anacardiaceae), which contains the major flavonoids fustin, fisetin, and sulfuretin, is known to have anti-inflammatory effects. Using lipopolysaccharide (LPS)—induced RAW264.7 cells, we examined which flavonoids were the most active compounds in the RVS extract. RVS extract dose-dependently reduced the production of nitric oxide, prostaglandin E₂, interleukin-6 (IL-6), and reactive oxygen species (ROS) induced by LPS. Only sulfuretin significantly suppressed IL-6 and ROS levels although the effects were smaller than those provided by the RVS extract at the equivalent concentration (0.25 µg/mL of pure sulfuretin and 100 µg/mL of RVS extract). Other flavonoids such as fisetin and fustin did not show anti-inflammatory effects at the levels typically contained in the RVS extract. Taken together, sulfuretin was postulated to be the major anti-inflammatory flavonoid in RVS extract.