Valerian (Valeriana officinalis L. s. lat., Valerianaceae) is a perennial that grows up to five feet (1.5 m) tall. Valerian has been used in Europe and the Middle East for more than 2,000 years as a sedative and for digestive and urinary tract disorders, coughs and asthma, headache, PMS, insomnia and fatigue. It was once used as a perfume and as a flavouring in soups.
Valerian is in demand as a sleep aid and as a sedative for nervous tension, hysteria, excitability, stress, and intestinal colic or cramps. Root extracts and oils are used to flavour tobacco, alcoholic beverages, root beer, and other food products.
Valerian rhizome and root preparations are found in many herbal sedative remedies, often in combination with skullcap, hops or passionflower. Valerian ranked 12th on the list of top selling mass market herbals, with US$8 million during the 52 week period ending July 12, 1998. This represents a growth rate of 35% over the previous year. Valerian ranked 10th in the list of top herbal supplement sales in the natural food market for 1998 (up from 18th in 1997), capturing 2% of sales. Health Canada has registered more than 100 commercial products containing valerian in its "Herbs and Natural Products" and "Homeopathic" categories, and has published a labelling standard for products claiming "sleep aid" or "sedative" therapeutic actions. The U.S. Pharmacopeia is requesting that further studies be done on valerian before it can be recommended as a sleep aid or sedative, but it is having quality standards established for publication in the National Formulary (it was previously listed in the USP 1820-1942 and NF 1942-1950). Valerian is marketed fresh or dried, as a tea, as a tincture, and as a liquid extract or concentrated infusion.
Valerian is native to most of Europe and part of northern Asia, with a complex of subspecies dispersed throughout temperate to subpolar Eurasia. It is cultivated in England, France, Belgium, Holland, Germany, eastern Europe, and Japan. It has become naturalized in the North West and North East U.S. and is reported to occur in Manitoba as an escapee from cultivation. Valerian grows well in hot or cold, wet or dry climates, but prefers rich heavy loam with lots of moisture.
The shoots arise from a short rhizome (horizontal underground stem) (2 - 4 cm long and 1 - 2 cm wide, which also gives rise to roots 2 - 15 cm long and 1 - 2 mm wide, which are wrinkled lengthwise) and sometimes the plant spreads from horizontal runners (stolons). The roots and fibrous rhizomes have a very strong odour and bitter taste. The stems are hollow and grooved, simple to slightly branched above. The leaves are opposite, deeply divided, with 7 - 10 pairs of toothed leaflets, becoming progressively smaller towards the top of the plant. The flowers, which bloom from June to August, are white or pale pink and fragrant, with irregular tubular corollas often spurred at the base, and three stamens. The inflorescence consists of terminal flat-topped clusters (a corymb). The tiny fruits have a crown of feathery fluff (pappus). Valerian is a highly variable species which has at least three subspecies and numerous intermediate populations. At least two other species of valerian, V. jatamansi Jones (Indian valerian) and V. edulis Nutt. ex Torr. & Gray subsp. procera F.G. Meyer (Mexican valerian) are also sold for medicinal purposes. In Manitoba there is also a native species, V. dioica L., which is used medicinally by our First Nations people.
Valerian grows on a wide range of soils, but moist, rich loam with pH 6.0 to 7.0 is best. It is listed as being hardy to zone 4, but has been cultivated experimentally here in Manitoba in zone 3 areas. (Consult your Ag Rep to determine which zone you are in). It likes full sun or partial shade. Direct seeding is done in mid-August, with germination of approximately 80% in about five weeks. Seeds can also be started in the greenhouse and transplanted after the last frost. Seeds germinate in about 20 days if started in flats. Light is required for germination, and seeds should be planted no deeper than ½ inch. (1 cm). Keep seeds constantly moist (30 - 60% soil moisture content). Stratification does not improve germination. Seeds lose their viability after two years. Root cuttings are also possible, but they are subject to many diseases.
Valerian can be propagated by crown or runner division in the spring or fall, and daughter plants can be collected at the end of the summer. Root division should be done early enough in the season to allow plants to become well established before winter. Plants will self-seed, and also spread by runners. Overcrowding can be a problem that decreases vitality, so transplants should be spaced on 12 - 15 inch (40 cm) centres, and the whole planting should be dug up and divided every 3 years.
Extra nitrogen is very important in cultivation. Valerian will produce larger roots if fertilized with a standard NPK mix. Side dress with compost in the second year. Valerian should be rotated with nitrogen fixers.
Mechanical or hand weeding is required.
There are no reported insect or disease problems in Manitoba, but Verticillium wilt and Rhizoctonia root rot have been observed in root cuttings in other areas. Cats may destroy plants, as it is said that valerian may have the same effect on them as catnip.
Roots are harvested after the first frost in the fall of the second season. The tops can be mowed first and the seed collected for planting next season. The roots and rhizomes can then be dug by hand or shallowly plowed. Even the fibrous roots and root hairs should be collected.
The roots should be carefully cleaned, then dried in the shade with a gentle air flow and low heat (<100°F, 40°C). Larger pieces should be cut so that they dry faster. Rapid drying at a low temperature is necessary to prevent enzymatic and thermal decomposition of the active ingredients. The odour becomes more pronounced with drying. Storing the dried root in olive oil may maintain the stability of the active ingredients. For maximum valepotriate content, the dried herb can be powdered and pressed into tablets, which should be coated pills for optimum efficacy. Extraction is generally done with 70% ethanol in a herb to extract ratio of 4-7:1, which is subsequently further concentrated to give a tincture of 20% concentration weight by volume. Aqueous extracts, prepared in a herb to extract ratio of 5:1 are also sold, but are not comparable in their chemistry or pharmacology to the alcoholic extracts.
As with any medicinal herb crop, quality control is essential to achieve a good selling price, particularly in the face of the anticipated intense competition in the next few years. Quality control procedures for production are described in Health Canada’s Good Manufacturing Practices: Supplementary Guidelines for the Manufacture of Herbal Medicinal Products.
Valerian, like most herbs, has more than one active ingredient. Standardization is generally based on the root’s content of the iridoid valepotriates, which are a mixture of related valerates, dihydrovalerates, and valerosidate. Valepotriates may be present in as much as 2% but an acceptable minimum content would be 0.8% of the dry weight of the root. Mexican valerian can have up to 8% valepotriates, which is actually too high to be desirable for therapeutic use. The valepotriates are highly unstable so processing and storage methods will have a significant effect on the final concentration in the product.
The pungent oil of the root also contains a number of biologically active constituents, including sesquiterpenoids such as valerenic acid (an identity marker), valerenyl esters such as acetoxyvalerenic acid (also suitable as an identity marker), valerenolic acid, and acetylvalerenolic acid. The essential oil content of the root varies from 0.3 - 0.8% and should be at least 0.5%. Independent laboratory analysis of 20 different commercial valerian products sold in Canada for their content of valerenic acid as a measure of quality found the levels to vary from 0.012 mg/g to 3.2 mg/g, almost a 300-fold range. The highest levels were found in a valerian product made by a Manitoba company.
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