Effects of St John's wort on hyperthermia.
Article Type: Brief article
Subject: Antianxiety agents (Dosage and administration)
Antianxiety agents (Comparative analysis)
Anxiety (Complications and side effects)
Anxiety (Drug therapy)
Fever (Risk factors)
Hyperthermia (Risk factors)
Author: Barnes, Cara
Pub Date: 03/22/2007
Publication: Name: Australian Journal of Medical Herbalism Publisher: National Herbalists Association of Australia Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2007 National Herbalists Association of Australia ISSN: 1033-8330
Issue: Date: Spring, 2007 Source Volume: 19 Source Issue: 1
Geographic: Geographic Scope: Australia Geographic Code: 8AUST Australia
Accession Number: 174818458
Full Text: Grundmann O, Kelber O, Butterweck V, 2006. Effects of St. John's Wort Extract and Single Constituents on Stress-Induced Hyperthermia in Mice. Planta Med 72:1366-71.

Anxiety disorders are often accompanied by an overactive autonomic nervous system reflected by an increase in body temperature and heart rate. This study used this to determine the efficacy of different substances on reducing anxiety in mice.

The basal temperature was recorded for each mouse, its temperature one hour following oral treatment and after 10 min of being exposed to an open field (placed in a large open body with three 60W lights suspended from above) stress session. The mice were treated with either buspirone (10mg/kg), fluoxetine (10mg/kg), imipramine (20mg/kg), diazepam (5mg/kg), St Johns wort (Hypericum perforatum) (125mg/kg, 250mg/kg, 500mg/kg, 750mg/kg or 1000mg/kg) or various single constituents found in St John's wort (SJW).

When compared to the control group, fluoxetine, imipramine and SJW (at concentrations of 125 mg/kg, 750 mg/kg and 1000 mg/kg) had no effect on stress induced hyperthermia (SIH). Buspirone and SJW 500 mg/kg significantly suppressed SIH, however diazepam and SJW 250 mg/kg completely abolished SIH (indicating a U-shaped dose response curve). Also effective against SIH were the following St John's wort constituents: hyperoside (1.2 mg/kg), isoquercitrin (1.2 mg/kg), quercitrin (0.6 mg/kg), miquelianin (1.2 mg/kg), rutin (1 mg/kg), amentoflavone (0.1 mg/kg) and hypericin (0.1 mg/kg).

The authors speculated that the ability of the compounds to suppress or abolished SIH may reflect whether they are partial or full 5-[HT.sub.1A] receptor agonists. This study also confirmed that the anxiolytic activity of St John's wort is not attributable to one specific compound.

Cara Barnes

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