Hyperforin is a natural activator of the steroid X receptor (active at 0.1 to 0.5 μg/ml) and inhibitor of several cytochrome P450 (CYP) isoforms (IC50 = 10 μg/ml for CYP2D6). It can also inhibit microsomal prostaglandin E2 synthase-1 (mPGES-1; IC50 = 1 μM), 5-lipoxygenase activating protein, and sirtuins.
