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

Hypericin, an active component of Hypericum perforatum, was evaluated for the regulation of interleukin-12 (IL-12) production in mouse macrophages. Hypericin significantly inhibited IL-12 production in lipopolysaccharide-activated macrophages in a dose-dependent manner (IC₅₀ = 1.45 μg/ml). Furthermore, hypericin potently inhibited the activation of IL-12 gene promoter, suggesting that hypericin negatively regulated IL-12 production at the transcription level. These results may explain some known biological activities of hypericin including its anti-rheumatic effect.