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Valerian (herb)

Valerian (Valeriana officinalis, Valerianaceae) is a hardy perennial flowering plant, with heads of sweetly scented pink or white flowers. The flowers are in bloom in the northern hemisphere from June to September. Valerian was used as a perfume in the sixteenth century.

Native to Europe and parts of Asia, Valerian has been introduced into North America. It is consumed as food by the larvae of some Lepidoptera (butterfly and moth) species including Grey Pug.

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. The garden flower red valerian is also sometimes referred to as "valerian" but is a different species, from the same family but not particularly closely related.

Valerian, in pharmacology and phytotherapic medicine, is the name of a herb or dietary supplement prepared from roots of the plant, which, after maceration, trituration, dehydration processes, are conveniently packaged, usually into capsules, that may be utilized for certain effects including sedation and anxiolytic effect.

The amino acid Valine is named after this plant.

History

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.

Etymology

The name Valerian comes from the Latin word valere, meaning "to be strong or healthy", generally thought to refer to its medicinal use, though many references suggest that it also refers to the strong odor.

An explanation for the theory regarding the etymological reference to the strong odor is that the herb was also known as "Phou" or "Fy" in antiquity . «Phou» or «fy» is describing a common expression of the peoples of the European continent when smelling a dried Valerian root. According to folk belief this medicine could turn everything painful into good. It was therefore called "wenderot" or similar in Germanic language groups, meaning the root that could turn things bad to good. Domestic animals, pets, especially cats become ardent when they smell the herb.

Valerian extract

Biochemical composition

Known pharmacologically active compounds detected in valerian extract are:

Mechanism of action

Because of valerian's historical use as a sedative, anti-convulsant, 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, as a mild sedative in particular, remains unknown. Valerian extracts appear to have some affinity for the GABAA (benzodiazepine) receptor, but this activity does not appear to be mediated by valerenic acid, but rather by the relatively high content of γ-aminobutyric acid (GABA) itself.

Valerian also contains isovaltrate, which has been shown to be an agonist for adenosine A1 receptor sites.

Preparation

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 percent though an average yield rarely exceeds 0.8 percent. This variation in quantity is partly explained by location: a dry, stony soil, yielding 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 or wet dog. Valerian tea should not be prepared with boiling water, as this may drive off the lighter oils.

Medicinal use

Valerian is used for insomnia and other disorders.

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).

Valerian is used against sleeping disorders, restlessness and anxiety, and as a muscle relaxant. Valerian often seems only to work when taken over longer periods (several weeks), though many users find that it takes effect immediately. Some studies have demonstrated that valerian extracts interact with the GABA and benzodiazepine receptors. Valerian is also used traditionally to treat gastrointestinal pain and irritable bowel syndrome. However, long term safety studies are missing. As valepotriates may be potential mutagens, valerian should only be used after consultation with a physician.

Valerian is sometimes recommended as a first-line treatment when benefit-risk analysis dictates. Valerian is often indicated as transition medication when discontinuing benzodiazepines.

Valerian has uses in herbal medicine as a sedative. The main current use of valerian is as a remedy for insomnia, with a recent meta-analysis providing some evidence of effectiveness. It has been recommended for epilepsy but that is not supported by research (although an analogue of one of its constituents, valproic acid, is used as an anticonvulsant and mood-stabilizing drug). Valerian root generally does not lose effectiveness over time.

While shown to be an effective remedy for the reduction of anxiety, it has also been reported to cause agitation, headaches and night terrors in some individuals. This may be due to the fact that some people lack a digestive conversion property necessary to effectively break down Valerian. One study found that valerian tends to sedate the agitated person and stimulate the fatigued person, bringing about a balancing effect on the system.

Oral forms, usage and adverse effects

Oral forms

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.

Usage

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 non-toxic but may cause side effects in excessive doses.

Adverse effects

Few adverse events attributable to valerian have been reported. Large doses (500+mg) or chronic use 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. In some individuals, valerian can cause stomach ache, anxiety, and night terrors (see above). Products containing valerian extracts may also cause an individual to test positive for benzodiazepines in most standard drug screens. Though some people like the earthy scent, many find it unpleasant. Overall, Valerian generally comes with very mild side effects and is considered a safe dietary supplement. In rare cases, Valerian may cause an allergic reaction, typically as a skin rash, hives, or difficulty breathing.

Effect on cats and rats

An unusual feature of valerian is that the essential oil of valerian root is a cat attractant similar to catnip. The active compound in valerian for this is actinidine. Cat attractants might mimic the odor of cat urine which is caused by 3-mercapto-3-methylbutan-1-ol (MMB). Anecdotes state that valerian is also attractive to rats, so much so that it had been used to bait traps. Some versions of the legend of the Pied Piper of Hamelin have him using valerian, as well as his pipes, to attract the rats. This might be related to the change of aversion into attraction to cat urine in rats infected with the parasite Toxoplasma gondii.

Valerian's effect on cats is featured as a clue in two works by Agatha Christie.

Notes

See also

External links

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