Inhibition of interleukin-12 production in lipopolysaccharide-activated mouse macrophages by hpyericin, an active component of Hypericum perforatum

Hypericin, an active component of Hypericum perforatum, was evaluated for t he regulation of interleukin-12 (IL-12) production in mouse macrophages. Hy pericin significantly inhibited IL-12 production in lipopolysaccharide-acti vated macrophages in a dose-dependent manner (IC50 =1.45 mug/ml). Furthermo re, hypericin potently inhibited the activation of IL-12 gene promoter, sug gesting that hypericin negatively regulated IL-12 production at the transcr iption level. These results may explain some known biological activities of hypericin including its anti-rheumatic effect.