Anti-Inflammatory Effect of Quercetin on RAW 264.7 Mouse Macrophages Induced with Polyinosinic-Polycytidylic Acid

Quercetin (3,3′,4′,5,6-Pentahydroxyflavone) is one of well-known antioxidants and a flavonol found in many fruits, leaves, and vegetables. Quercetin is also well-known to have anti-inflammatory effects on lipopolysaccharide-induced macrophages. However, the effects of quercetin on virus-induced macrophages are not fully reported. In this study, the anti-inflammatory effect of quercetin on double-stranded RNA (dsRNA)-induced macrophages was examined. Quercetin at concentrations of up to 50 μM significantly inhibited the production of nitric oxide (NO), IL-6, MCP-1, IP-10, RANTES, GM-CSF, G-CSF, TNF-α, LIX,VEGF, and MIP-1α as well as calcium release in dsRNA [50 µg/mL of polyinosinic-polycytidylic acid]-induced RAW 264.7 mouse macrophages (P < 0.05). Quercetin at concentrations of up to 50 μM also significantly inhibited mRNA expression of signal transducer and activated transcription 1 (STAT1) and STAT3 in dsRNA-induced RAW 264.7 (P < 0.05). In conclusion, quercetin has alleviating effects on viral inflammation concerned with its inhibition of NO, cytokines, chemokines, and growth factors in dsRNA-induced macrophages via the calcium-STAT pathway.