Medically reviewed on February 12, 2018
Scientific Name(s): Valeriana officinalis L. Family: Valerianaceae . A number of other species have been used medicinally, including Valeriana wallichi DC, Valeriana sambucifolia Mik., and the related Centranthus ruber L.
Common Name(s): Baldrian , cat's love , cat's valerian , garden heliotrope , garden valerian , kesso root , radix valerianae , St. George's herb , valerian fragrant , valerian , vandal root
The evidence to support the common use of valerian in insomnia remains weak. However, as valerian preparations seem to have a wide margin of safety, further trials for insomnia and anxiety may be warranted.
Anxiety: Valeprotriates 150 mg/day in 3 divided doses for 4 weeks has been used in a clinical trial. Other trials used the dried herb 0.5 to 2 g, extract 0.5 to 2 mL, and valerian tincture 2 to 4 mL for anxiety. Insomnia: Valerian extract 400 to 600 mg/day taken 1 hour before bedtime for 2 to 4 weeks has been used in clinical trials. Single-dose studies have consistently found no effect for single doses of valerian in insomnia.
Contraindications have not been identified.
Information regarding safety and efficacy in pregnancy and lactation is lacking.
None well documented.
In general, clinical studies have found valerian to have a wide margin of safety, be devoid of adverse effects, and have fewer adverse reactions than positive control drugs, such as diazepam. Headache and diarrhea have been reported in clinical trials, but hangover is seldom reported.
Valerian has been classified as GRAS (generally recognized as safe) in the United States for food use; extracts and the root oil are used as flavorings in foods and beverages. The observed in vitro cytotoxicity of valepotriate compounds may not be relevant in vivo because of limited absorption.
Members of the genus Valeriana are herbaceous perennials widely distributed in the temperate regions of North America, Europe, and Asia. The hollow stemmed plant can grow up to 2 m and is branched at the terminal end with opposite leaves and small white or pink flowers. Fruits are oblong, 4-ridged, and single seeded. Of approximately 200 known species, the Eurasian Vakeruaba officinalis is most often cultivated for medicinal use. The dried rhizome used in valerian extracts has numerous rootlets and one or more stolons and contains a volatile oil with a distinctive, unpleasant odor. 1 , 2 , 3 , 4
Valerian has been used in Unani, Ayurvedic, and traditional Chinese health systems and for homeopathic uses for cardiotonic and sedative properties, as well as in epilepsy, hysteria, and other conditions. 5 Despite its odor, valerian was considered a perfume in 16th-century Europe. The tincture has been used for its sedative properties for centuries; it is still widely used in France, Germany, and Switzerland as a sleep aid. 6 Other uses attributed to valerian include a digestive aid, emmenagogue, and antiperspirant. 2
Three distinct classes of compounds have been associated with the sedative properties of valerian. These compounds consist of mono- and sesquiterpenes and iridoid triesters (valepotriates). Other compounds identified include flavonoids, triterpenes, lignans, and alkaloids. The composition of the volatile oil varies markedly between cultivars and species, as does the amount and relative proportion of cytotoxic valepotriates, making chemical standardization difficult but highly desirable.
The most important sesquiterpenes include valerenic acid and its congeners, although in Japan, V. officinalis var. latifolia , kessyl alcohols, and esters predominate. Valtrate, acevaltrate, and didrovaltrate are the most important iridoids; European valerian extracts were formerly standardized on these unstable compounds, which have a short shelf life in the tincture.
The alkaloid concentration in roots and rhizomes is low, usually less than 0.2%. The aqueous extract of valerian contains substantial quantities of gamma-aminobutyric acid (GABA); however, it is doubtful whether GABA penetrates the blood-brain barrier.
Many analytical high performance liquid chromatographic methods have been developed for the sesquiterpenes and valepotriates. The seasonal variation in valerenic acids and valepotriates has been studied. Tissue culture of valerian species has focused on the production of valepotriates. 2 , 7 , 8 , 9 , 10 , 11 , 12
Uses and Pharmacology
Several in vitro and animal experiments have attempted to elucidate the mechanism of action for various valerian compounds. Many of these experiments provide contradictory evidence, but most attribute the observed actions of valerian extracts to central actions on GABA, serotonin, and adenosine receptors. The sesquiterpene valerenic acid and its derivatives and the valepotriates are generally thought to be the active constituents; however, wide variations in the composition of commercial preparations make interpretation of clinical data difficult. 9 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22Anxiolytic effect
Both a meta-analysis and systematic review comment on the lack of trials meeting inclusion criteria because of poor methodology, the use of healthy volunteers, and combination therapies. 14 , 23 One small, pilot clinical trial meeting inclusion criteria evaluated the effect of valepotriates 150 mg per day in 3 divided doses over 4 weeks in generalized anxiety disorder. 24 No difference was demonstrated for the standardized valerian extract versus placebo or diazepam 20 mg. 24 Until studies with a larger sample size are conducted, the efficacy of valerian remains unclear. 14 , 23
Another review of clinical trials and in vitro experiments suggests the effect of valerian may be because of anxiolytic action, rather than sedation. 13 This was demonstrated by a laboratory experiment with rodents that found no decrease in spontaneous locomotor activity and no increase in ether-induced anesthesia, but did find a reduction in anxiety using the elevated plus maize test. 25 Older experiments in rodents found conflicting results for spontaneous motor activity. 22 , 26Insomnia
Both a systematic review and a meta-analysis of quality clinical trials found the results inconclusive for valerian use in insomnia. 6 , 30 However, pooled results for the dichotomous outcome of improved sleep quality (improved or not) do find in favor of valerian (relative risk, 1.8; 95% confidence interval, 1.2 to 2.9). 6 Results for sleep latency could not be pooled because of heterogeneity of measures. Issues raised by the reviews include the lack of standardization of the valerian extracts used and possibility of publication bias. 6 , 30 Reviews of older trials not included in the systematic reviews or meta-analysis found valerian to exert an effect similar to the benzodiazepines, but a number of negative trials are also described. 5 , 13
Further randomized clinical trials, published after the meta-analysis, have found no differences for outcome measures for valerian versus placebo in insomnia. 31 , 32 In a large clinical trial, valerian extract 600 mg taken 1 hour before bedtime for 2 weeks demonstrated no difference from placebo for any outcome measure, although a trend towards valerian was found. 31 A small clinical trial found no difference for sleep latency between placebo or valerian extract 500 mg over 4 weeks in nonorganic sleep disorder. 32Other effects
The valepotriates, isovaltrate, and valtrate, along with valerenone, had antispasmodic effects in isolated guinea pig ileum and other smooth muscle preparations. 33
Valerian had no effect on haloperidol-induced orofacial dyskinesia in rats. 34
Oral administration of valerian root extracts was protective against vasopressin-induced coronary spasms and pressor response in guinea pigs. 7 In the same experiment, bronchial resistance was reduced in both histamine- and antigen-induced bronchospasm. 7
A dose of a commercial preparations of valerian extract 600 mg in healthy subjects peaked at 30 minutes to 2 hours, with an elimination half-life of 1.1 ± 0.6 hours, and the marker valerenic acid was in the serum for at least 5 hours after dosing. 35Anxiety
A clinical trial evaluating valerian as an anxiolytic used valeprotriates 150 mg in 3 divided doses for 4 weeks. 24 Other trials have used valerian dried herb 0.5 to 2 g, extract 0.5 to 2 mL, and tincture 2 to 4 mL. 14Insomnia
Valerian extract 400 to 600 mg taken 1 hour before bedtime for 2 to 4 weeks has been used in clinical trials evaluating valerian in insomnia. 13 , 31 , 32 A study conducted in children with insomnia (mean age, 11 years) used valerian extract 20 mg/kg body weight at night for 2 weeks. No adverse reactions were noted at this dosage; however, results were inconclusive. 6 , 36 Studies have consistently found no effect for a single dose of valerian in improving sleep latency or quality. 27 , 28 , 29
Valerian extract up to 1,215 mg has been used as a sedative, but clinical trials have not established an optimal dose, and issues of standardization of content and preparation quality have been raised. 6 , 13 Many commercial preparations exist either as valerian alone or in combination with other compounds.
Despite common use without apparent harm during pregnancy, the use of valerian preparations in pregnancy and lactation cannot be supported without evidence of safety. Widespread differences in dosages, duration, and preparations exist, and the stage of pregnancy may be a factor. 37 Valerian is reported in the Complete German Commission E Monographs to stimulate uterine contractions. 38 Information regarding safety and efficacy in pregnancy and lactation is lacking.
In vitro studies have suggested valerian inhibits both CYP3A4 metabolism and P-glycoprotein activity, 39 but clinical studies showed no effect of valerian on midazolam, caffeine, chlorzoxazone, debrisoquine, dextromethorphan, or alprazolam levels. 40 A paradoxical lack of potentiation by valerian on the anesthetic isoflurane was demonstrated, while a cumulative effect emerged from the anesthetic in rats when administered with midazolam. 41 Animal studies have also shown potentiation of thiopental and pentobarbital-induced sleep, while no potentiation of the sedative effects of alcohol have been noted. 13 The potential for interactions remains a theoretical possibility.
Valerian has been classified as GRAS in the United States for food use; extracts and the root oil are used as flavorings in foods and beverages. 13
Generally, clinical studies have found that valerian has a wide margin of safety, is devoid of adverse effects, and has fewer adverse reactions than positive control drugs, such as diazepam. Headache and diarrhea have been reported in clinical trials, but hangover is seldom reported. 5 , 6 , 13 , 24 , 30 , 31 , 32
An intentional overdose has been reported, in which 20 times the recommended dose was ingested; the patient experienced mild symptoms that resolved within 24 hours. 42 A case of withdrawal after chronic use of valerian has been reported; however, the complex nature of the patient's medical history provides weak evidence of valerian's role. 43 Farmers growing valerian were evaluated for adverse reactions, with few notable effects observed. 44
Concern was raised following the discovery that valepotriates are mutagenic in the Ames assay; however, their poor bioavailability and hepatic detoxification makes them a dubious source of toxicity for patients. 2 , 45 The cytotoxicity of baldrinal compounds (metabolites of the valepotriates) is higher in vivo than in vitro because they are more readily absorbed, and these metabolites have been detected in commercial preparations. 2
No teratogenicity or overt toxicity of valepotriate compounds was found in rodents in 2 different studies. 2 , 13 , 46 Mice receiving doses of valerian more than 1 g/kg by oral and intraperitoneal routes have experienced ataxia, muscle relaxation, and hypothermia. 47
No evidence of hepatitis was observed following consumption of oral valerian at average dosages of 2.5 g/day for 4 years. 46
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