Hyperforin inhibitors dopamine

The hypericin fraction was initially reported to have MAO-A and -B inhibitor properties. Later studies found that the concentration required for this inhibition was higher than that achieved with recommended dosages. In vitro studies using the commercially formulated hydroalcoholic extract have shown inhibition of nerve terminal reuptake of serotonin, norepinephrine, and dopamine. While the hypericin constituent did not show reuptake inhibition for any of these systems, the hyperforin constituent did. Chronic administration of the commercial extract has also been reported to significantly down-regulate the expression of cortical 13 adrenoceptors and up-regulate the expression of serotonin receptors (5-HT2) in a rodent model. 

Assays with extracts devoid of hypericin but with a high content of hyperforin as well as assays with pure hyperforin demonstrated that this metabolite can modulate the function of various neurotransmitters involved in depression, being a potent inhibitor of serotonin, dopamine, noradrenaline and GABA uptake with almost equal potency. Moreover, results from clinical studies evidenced that the antidepressant efficacy of Hypericum preparations correlates with their content of hyperforin [6,87],... 

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