Possible Interaction: Serotonin and St John's Wort

“ St. John's wort extract has a clear inhibitory effect on the neuronal uptake not only of serotonin , noradrenaline, and dopamine but also of gamma-aminobutyric acid (GABA) and L-glutamate.”

“Like other working parties, we were only able to identify a weak inhibitory effect of the extract and the pure substance hypericin on the monoamine oxidases A and B. Similarly to synthetic antidepressants, St-John's wort exerts marked inhibitory effects on synaptosomal uptake of serotonin and noradrenaline.”

“ Hypericum species could normalize brain serotonin level.”

“In addition, St. John's wort is a potent uptake inhibitor of the neurotransmitters serotonin , norepinephrine and dopamine all of which have a role in mood control.”

“Thus, the potency of various St. John's wort extracts for inhibiting the neuronal uptake of serotonin , a characteristic of conventional antidepressants such as fluoxetine, increases with increasing hyperforin content.”

“It was … pretreatment of SJW to rats did not prevent stress-induced … plasma corticosterone levels however it increases serotonin synthesis by virtue of inhibiting hepatic TDO enzyme activity and its gene expression, ascertaining the … that there exists an inverse relationship between hepatic TDO enzyme activity and brain 5-HT.”

“Classic synthetic antidepressant drugs, as well as St John's wort extract (SJW), directly inhibit the re‐uptake of norepinephrine (NE) and/or serotonin (5‐HT ) into pre‐synaptic axons.”

“It is concluded that SJW treatment alter stress induced augmented 5-HT levels by decreasing precursor availability to the brain and that serotonergic system is involve in the mechanism of action of the drug.”

“The major components of St. John's Wort , hyperforin and hypericine were significantly decreased in serotonin transport activity.”

“In in‐vitro experiments, St John's wort inhibited brain synaptosomal [3H]serotonin uptake in mice with little effect on specific [3H]paroxetine binding.”