Valerian extract characterized by high valerenic acid and low acetoxy valerenic acid contents demonstrates anxiolytic activity

Inst. Pharmacology and Toxicology, Otto-von-Guericke University, Magdeburg, Germany.
Phytomedicine: international journal of phytotherapy and phytopharmacology (Impact Factor: 3.13). 08/2012; 19(13):1216-22. DOI: 10.1016/j.phymed.2012.08.003
Source: PubMed


Valerian is one of the most commonly used herbal remedies for the treatment of insomnia and anxiety. Valerian extracts allosterically modulate GABAA receptors, an action related to valerenic acid, which is one of the active compounds determined from pharmacological studies. Derivatives of valerenic acid, i.e. acetoxy valerenic acid or hydroxy valerenic acid, do not allosterically modulate GABAA receptors, but they bind to identical binding sites. Therefore, the question arises whether they might interfere with the effects of valerenic acid. Two valerian extracts were tested in the elevated plus maze test and the tail suspension test for anxiolytic and antidepressive activity, respectively. Reference substances were diazepam (1.0mg/kg) and imipramine (30mg/kg). The extracts were standardized to the identical total amounts of the acids (0.1; 0.5; 1.0 and 2.0mg/kg), i.e. valerenic and acetoxy valerenic acid, but the ratio between the acids was different (12:1 and 1:1.5). The extract with the ratio 12:1 prolonged the time spent on the open arm significantly when 0.5mg/kg was applied. Of the other extract, with the ratio 1:1.5, four times that amount was required (2.0mg/kg). Both of the tested extracts did not show any antidepressive effect, rather the other way around, the extract with the ratio 1:1.5 prolonged the immobility phase. However, since the core body temperature was reduced by the 1.0 and 2.0mg/kg extract dose, the prolongation may be related to the temperature phenomenon and is not indicative of a specific depressive action. In conclusion, the anxiolytic activity of the valerian extract seems rather related to valerenic acid and, moreover, standardization with respect to the total amount of valerenic acids, i.e. valerenic acid together with acetoxy valerenic acid, is misleading.

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Available from: Axel Brattström, Dec 12, 2014
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    ABSTRACT: The presented studies concern the determination of content and chemical composition of essential oil from plants of the Valeriana officinalis L. ('Lubelski' common valerian) cultivar grown in the south-eastern region of Poland, as well as the contents of valerenic acids, protein and ash in the discussed raw material. In the examined oil, the presence of 71 compounds was determined, and the predominant compound was bornyl acetate (15.42%), followed by elemol (8.01%), β-gurjunene (6.20%) and camphene (5.43%). The contents of sesquiterpene - valerenic and acetoxy valerenic acids in the examined valerian raw material was respectively: 0.0519 and 0.0677%. The total valerenic acid contents (0.1196%) are comparable to other Polish cultivars.
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    ABSTRACT: Background Valerian is commonly used for the treatment of insomnia and anxiety. Valerian extracts allosterically modulate GABA-A receptors and induced an anxiolytic activity. This activity is closely related to valerenic acid. In the present experiments it was investigated whether acetoxy valerenic acid may interfere with the anxiolytic action of valerenic acid. Methods Situational anxiety was measured using male CD-1 mice in the elevated plus maze test after oral administration of the test substances. In addition the body core temperature was measured. For the 3H-GABA binding assay dissected tissue from frontal cortex of male RjHan:WI rats were used. Statistical evaluation was performed by means of the non-parametric Kruskal-Wallies H-test, followed by the two-tailed Mann–Whitney U-test. Results Adding of acetoxy valerenic acid abolished the anxiolytic action of valerenic acid. There was no effect on body core temperature. Moreover, the valerian extract did not show any affinity to benzodiazepine binding sites. Conclusion The determining compound for the observed anxiolytic effect of the valerian extract is its content of valerenic acid.
    BMC Complementary and Alternative Medicine 07/2014; 14(1):267. DOI:10.1186/1472-6882-14-267 · 2.02 Impact Factor
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