Determination of hypericin and pseudohypericin from Hypericum perforatum in rat brain after oral administration

The popularity of St. John’s Wort (SJW) extracts for treating mild to moderate depression has increased over the last decades and great effort has been devoted to identify the active principle of SJW extract. Previous investigations suggest the contribution of at least three classes of compounds, the phloroglucinols, the quercetin flavonoids, and the phenanthroperylenequinones, to the clinical efficiency of SJW extracts. Up to now, a plausible molecular mechanism of action has been described only for the phloroglucinols. For the flavonoids and the phenanthroperylenequinones different targets were proposed on the basis of pharmacological studies. The vast majority of these targets are located in the CNS and therefore increasing interest in the question of the CNS availability of these substances arose. Recently, the ability of phloroglucinols and flavonoids to penetrate the blood brain barrier could be demonstrated. For the phenanthroperylenequinones an examination of CNS bioavailability is still missing.