Quercetin inhibits LPS-induced nitric oxide and tumor necrosis factor-alpha production in murine macrophages

High amounts of nitric oxide and TNF-alpha generated by activated macrophages induce several pathophysiological conditions during acute and chronic inflammation. Identification of new pharmacological reagents that can prevent TNF-alpha and/or NO overproduction is of considerable medical interest. In this report we provide evidence that the overproduction of TNF-alpha and NO by LPS stimulated macrophages can be markedly inhibited by quercetin, a major active component of plant Rhododendron cinnabarium.