VALERIAN, a genus of herbaceous perennial plants of the natural order Valerianaceae. Two species Valeriana officinalis and V. dioica are indigenous in Britain, whileathird, V. pyrenaica, is naturalized in some parts. The valerians have opposite leaves and small flowers, usually of a white or reddish tint, and arranged in terminal cymes. The limb of the calyx is remarkable for being at first inrolled and afterwards expanding in the form of a feathery pappus which aids in the dissemination of the fruit. The genus comprises about 150 species, which are widely distributed in the temperate parts of the world. In medicine the root of V. officinalis is intended when valerian is mentioned. The plant grows throughout Europe from Spain to the Crimea, and from Iceland through northern Europe and Asia to the coasts of Manchuria. Several varieties of the plant are known, those growing in hilly. situations being considered the most valuable for medicinal purposes.
Valerian is cultivated in England (in several villages near Chesterfield in Derbyshire), but to a much greater extent in Prussian Saxony (in the Habit after Curtis, Flora Londinemis.
neighbourhood of FIG. I. Valerian (Valeriana officinalis), one- Colleda, north of third natural size. I, flower; 2, flower after Weimar) in Hoi- removal of corolla ; 3, fruit crowned by the , , j . feathery pappus. I, 2, 3 enlarged, land and in the United States (Vermont, New Hampshire and New York). The dried root or rhizome consists of a short central erect portion, about the thickness of the little finger, surrounded by numerous rootlets about fa of an inch in diameter, the whole being of a dull brown colour. When first taken from the ground it has no distinctive smell; but on drying it acquires a powerful odour of valerianic acid. This odour, now regarded as intolerable, was in the 16th century considered to be fragrant, the root being placed among clothes as a perfume (Turner, Herbal, 1568, part iii. p. 76), just as V. celtica and some Himalayan species of the genus are still used in the East. By the poorer classes in the north of England it was esteemed of such medicinal value that " no broth, pottage or physical meat " was considered of any value without it (Gerard, Herball, 1633, p, 1078). The red valerian of gardens is Centranthus ruber, also belonging to the Valerianaceae; but Greek valerian is Polemonium coeruleum, belonging to the natural order Polemoniaceae. Cats are nearly as fond of the smell of this plant as of the true valerian, .and will frequently roll on the plant and injure it.
The chief constituent of valerian is a volatile oil, which is present in the dried root to the extent of 1-2 %, plants growing on dry or stony soil being said to yield the largest quantity. The oil is of complex composition, containing valerianic (valeric), formic and acetic acids combined with a terpene, CicHie; the alcohol known as borneol; and pinene. The valerianic acid present in the oil is not the normal acid, but isovalerianic acid. It occurs in many plants and in cod-liver oil. It is strongly acid, burning to the palate, and with the odour of the plant. The oil is soluble in thirty parts of water and readily in alcohol and ether. The British Pharmacopeia contains the tinctura valerianae ammoniata, containing valerian, oil of nutmeg, oil of lemon and ammonia. It is an extremely nauseous and offensive preparation. The valerianate of zinc is also official in Great Britain, but, like valerianic acid itself, it is pharmacologically inert and therapeutically useless.
Valerian acts medicinally entirely in virtue of its volatile oil, which exerts the actions typical of its class. The special use of this drug, like that of others which contain an offensive volatile oil such as asafoetida is in hysteria or, as it is more properly styled, neuromimesis. It is generally believed that the drug acts in virtue of its unpleasant odour and taste, which cause the patient to display so much volition as shall enable him or her to control the symptoms and thereby obtain the discontinuance of the drug. Good results are sometimes obtained, however, when the drug is given in capsules or in some other form which puts this mode of action out of the question. Binz of Bonn has shown that the volatile oils act as sedatives of the motor cells in the anterior horns of grey matter in the spinal cord, and it is probable that this action may account for the good results often obtained by the use of valerian in neuromimesis; though there is little doubt that the modus operandi above described may also come into play. The valerianates of iron, quinine, guaiacol and sodium share with that of zinc the disability of exerting no action attributable to their acid radicle, but have frequently been employed. Valerianic diethylamide, or valyl, has also been employed as a substitute for the preparations in ordinary use.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)