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Valerian (Valeriana officinalis, Valerianaceae) is a hardy perennial flowering plant, with heads of sweetly scented pink or white flowers which bloom in the summer months. Valerian flower extracts were used as a perfume in the sixteenth century.
Other names used for this plant include garden valerian (to distinguish it from other Valeriana species), garden heliotrope (although not related to Heliotropium) and all-heal. Red valerian, often grown in gardens, is also sometimes referred to as "valerian", but is a different species (Centranthus ruber) from the same family and not very closely related.
Valerian, in pharmacology and herbal medicine, is the name of an herb or dietary supplement prepared from roots of the plant, which, after maceration, trituration and dehydration processes, are packaged, usually into capsules. Based on its pharmacological mode of action, valerian root has been demonstrated to possess sedative and anxiolytic effects. The amino acid valine is named after this plant.
Valerian has been used as a medicinal herb since at least the time of ancient Greece and Rome. Hippocrates described its properties, and Galen later prescribed it as a remedy for insomnia. In medieval Sweden, it was sometimes placed in the wedding clothes of the groom to ward off the "envy" of the elves. In the sixteenth century the Anabaptist reformer Pilgram Marpeck prescribed valerian tea for a sick woman.
According to the Oxford English Dictionary (second edition 1989), valerian is derived from a Latin adjectival form of the personal name Valerius.
Known compounds detected in valerian that may contribute to its method of action are:
Because of valerian's historical use as a sedative, anticonvulsant, migraine treatment and pain reliever, most basic science research has been directed at the interaction of valerian constituents with the GABA neurotransmitter receptor system. These studies remain inconclusive and all require independent replication. The mechanism of action of valerian in general, and as a mild sedative in particular, remains unknown. Valerian extracts appear to have some affinity for the GABAA receptor, a class of receptors on which benzodiazepines are known to act.
Valerian also contains isovaltrate, which has been shown to be an inverse agonist for adenosine A1 receptor sites. This action likely does not contribute to the herb's sedative effects, which would be expected from an agonist, rather than an inverse agonist, at this particular binding site. Hydrophilic extractions of the herb commonly sold over-the-counter, however, probably do not contain significant amounts of isovaltrate (according to the paper cited previously).
The chief constituent of valerian is a yellowish-green to brownish-yellow oil which is present in the dried root, varying from 0.5 to 2.0 percent, though an average yield rarely exceeds 0.8 percent. This variation in quantity is partly explained by location; a dry, stony soil, yields a root richer in oil than one that is moist and fertile. The volatile oils that form the active ingredient are extremely pungent, somewhat reminiscent of well-matured cheese. Though some people remain partial to the earthy scent, some may find it to be unpleasant, comparing the odor to that of unwashed feet. Valerian tea should not be prepared with boiling water, as this may drive off the lighter oils.
Valerian is used for insomnia and other disorders as an alternative to benzodiazepine drugs, and as a sedative for nervous tension, excitability, stress and intestinal colic or cramps.
In the United States, valerian is sold as a nutritional supplement. Therapeutic use has increased as dietary supplements have gained in popularity, especially after the Dietary Supplement Health and Education Act was passed in 1994. This law allowed the distribution of many agents as over-the-counter supplements, and therefore allowed them to bypass the regulatory requirements of the Food and Drug Administration (FDA).
A 2006 systematic review of research and meta-analysis concluded that "The available evidence suggests that valerian might improve sleep quality without producing side effects." Valerian is used for sleeping disorders, restlessness and anxiety, and as a muscle relaxant. Certain data suggests that valerian has an effect that is calming but doesn't cause sleepiness the following day. When used as a sleeping aid, valerian appears to be most effective on users who have difficulty falling asleep. Also noteworthy is that valerian has been shown to have positive results on users who wake up during the night. Valerian often seems only to work when taken over longer periods (several weeks), though some users find that it takes effect immediately. Some studies have demonstrated that valerian extracts interact with the GABA receptors. Valerian is also used traditionally to treat gastrointestinal pain and irritable bowel syndrome. However, long term safety studies are absent.
It has been recommended for epilepsy, but that is not supported by research (although valproic acid—an analogue of one of valerian's constituents, valeric acid—is used as an anticonvulsant and mood-stabilizing drug). Valerian root generally does not lose effectiveness over time.
One study found valerian tends to sedate the agitated person and stimulate the fatigued person, bringing about a balancing effect on the system.
One study found valerian effective in controlling infantile rota viral diarrhea.
In ayurveda, valerian is considered to work on the nervous, digestive, and respiratory systems as a stimulant, antispasmodic, stomachic, sedative, analeptic, carminative, and nervine. While it is used for various disorders of these systems, it is noted that excessively, it may dull the mind or cause severe conditions such as central paralysis, thus it is recommended to be used under the supervision of an ayurvedic doctor. Possibly because of its dulling effects, another herb is mainly used for nerve and mind disorders like insomnia: jatamamsi (Nardostachys jatamansi).
Oral forms are available in both standardized and unstandardized forms. Standardized products may be preferable considering the wide variation of the chemicals in the dried root, as noted above. When standardized, it is done so as a percentage of valerenic acid or valeric acid.
Valerian's trade name is Valerin.
Dosage is difficult to determine due to the lack of standardization and variability in available forms. Typical dosages of the crude herb vary from 2–10 grams per day. Valerian root is nontoxic, but may cause side effects, such as giddiness and disorientation, when taken in large excessive doses.
Few adverse events attributable to valerian have been reported. Large doses may result in stomach ache, apathy, and a feeling of mental dullness or mild depression. Because of the herb's tranquilizer properties, it may cause dizziness or drowsiness, effects that should be considered before driving or operating heavy or hazardous equipment.
Because the compounds in valerian produce central nervous system depression, they should not be used with other depressants, such as alcohol, benzodiazepines, barbiturates, opiates, or antihistamine drugs. Moreover, non-pregnant adult human hepatotoxicity has been associated with short-term use (i.e., a few days to several months) of herbal preparations containing valerian and Scutellaria (commonly called skullcap). Withdrawal after long-term use in a male has also been associated with benzodiazepine-like withdrawal symptoms, resulting in cardiac complications and delirium.
The very limited animal and human data do not allow a conclusion as to the safety of valerian during pregnancy. Moreover, as a natural, unregulated product, the concentration, contents, and presence of contaminants in valerian preparations cannot be easily determined. Because of this uncertainty and the potential for cytotoxicity in the fetus and hepatotoxicity in the mother, the product should be avoided during pregnancy.
An unusual feature of valerian is that valerian root and leaves are a cat attractant similar to, and as safe as catnip. Valerian contains the cat attractant actinidine. Cat attractants might mimic the odor of cat urine, which is caused by 3-mercapto-3-methylbutan-1-ol (MMB). Anecdotal reports claim that valerian is also attractive to rats—so much so that it had been used to bait traps. Stories describe the Pied Piper of Hamelin using both his pipes and valerian to attract rats. Research also shows that valerian root is the strongest chemo-attractant of slime molds (Physarum polycephalum).