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[Mechanism of action of St. Johns wort extract].
Praxis (Bern 1994) 2000; 89(50):2111-21P

Abstract

Over the last few years St-John's wort preparations have been used in large quantities in Germany for treating mild to moderate depression. In the meantime the antidepressive action of these extracts has been proved in numerous placebo-controlled studies. Furthermore, a considerably lower adverse effect rate compared with classic antidepressants has been established. Analogously to other antidepressants, subchronic St-John's wort treatment of rats showed significant down-regulation of beta receptor density and a significant increase in 5HT2 receptors. The extract also exhibited antidepressant activity in animal pharmacological models of depression. Interest is now focused on identifying the underlying pharmacological mechanisms of action of this phytotherapeutic agent. 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. However, dopamine and uptake and neuronal uptake of GABA and L-glutamate are also inhibited. These effects may mainly be attributed to the substance hyperforin contained in the extract. An additional, as yet unknown, pharmacological mechanism of action of St-John's wort extracts is beginning to emerge. Although hyperforin shows similar properties to classical antidepressants, there are indications of a novel mechanism of action. Our laboratory is currently investigating the means by which St-John's wort extract, or its constituent hyperforin, develops its antidepressant action.

Authors+Show Affiliations

Pharmakologisches Institut für Naturwissenschaftler, J. W. Goethe-Universität Frankfurt.No affiliation info availableNo affiliation info available

Pub Type(s)

English Abstract
Journal Article
Research Support, Non-U.S. Gov't
Review

Language

ger

PubMed ID

11155494

Citation

Müller, W E., et al. "[Mechanism of Action of St. Johns Wort Extract]." Praxis, vol. 89, no. 50, 2000, pp. 2111-21.
Müller WE, Singer A, Wonnemann M. [Mechanism of action of St. Johns wort extract]. Praxis (Bern 1994). 2000;89(50):2111-21.
Müller, W. E., Singer, A., & Wonnemann, M. (2000). [Mechanism of action of St. Johns wort extract]. Praxis, 89(50), pp. 2111-21.
Müller WE, Singer A, Wonnemann M. [Mechanism of Action of St. Johns Wort Extract]. Praxis (Bern 1994). 2000 Dec 14;89(50):2111-21. PubMed PMID: 11155494.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - [Mechanism of action of St. Johns wort extract]. AU - Müller,W E, AU - Singer,A, AU - Wonnemann,M, PY - 2001/1/13/pubmed PY - 2001/3/17/medline PY - 2001/1/13/entrez SP - 2111 EP - 21 JF - Praxis JO - Praxis (Bern 1994) VL - 89 IS - 50 N2 - Over the last few years St-John's wort preparations have been used in large quantities in Germany for treating mild to moderate depression. In the meantime the antidepressive action of these extracts has been proved in numerous placebo-controlled studies. Furthermore, a considerably lower adverse effect rate compared with classic antidepressants has been established. Analogously to other antidepressants, subchronic St-John's wort treatment of rats showed significant down-regulation of beta receptor density and a significant increase in 5HT2 receptors. The extract also exhibited antidepressant activity in animal pharmacological models of depression. Interest is now focused on identifying the underlying pharmacological mechanisms of action of this phytotherapeutic agent. 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. However, dopamine and uptake and neuronal uptake of GABA and L-glutamate are also inhibited. These effects may mainly be attributed to the substance hyperforin contained in the extract. An additional, as yet unknown, pharmacological mechanism of action of St-John's wort extracts is beginning to emerge. Although hyperforin shows similar properties to classical antidepressants, there are indications of a novel mechanism of action. Our laboratory is currently investigating the means by which St-John's wort extract, or its constituent hyperforin, develops its antidepressant action. SN - 1661-8157 UR - https://www.unboundmedicine.com/medline/citation/11155494/[Mechanism_of_action_of_St__Johns_wort_extract]_ DB - PRIME DP - Unbound Medicine ER -