VALERIAN 331 



about 1-5 mm. thick are given off, as well as occasionally short, slender, 

 lateral branches. In the commercial drug the roots seldom exceed 

 10 cm. in length and 2 mm. in diameter ; they are plump or longi- 

 tudinally striated, but usually not much shrivelled. 



Sometimes the drug consists of small rhizomes about 5 mm. long, 

 which are crowned with the remains of several leaves and bear rather 

 short slender roots. These are formed from the lateral branches 

 (runners) produced by the principal rhizome, which bear cataphyllary 

 leaves ; the buds in the axils of these develop leaves, roots are deve- 

 loped below, and independent plants are produced. Such plants 

 may occasionally be found mingling their roots with those of the 

 principal rhizome. Had they been allowed to continue their growth, 

 they would ultimately have developed rhizomes as large as those 

 of the parent plant. 



The transverse section of the rhizome is irregular in outline and 

 exhibits a comparatively narrow bark separated by a dark line 

 (cambium) from an irregular circle of wood-bundles of varying size. 

 The section of a root shows a thick bark and small wood. 



Valerian rhizome has a powerful characteristic disagreeable odour 

 and a camphoraceous, slightly bitter taste. The odour of the fresh 

 rhizome, though disagreeable, is not strong, but it develops, during 

 the drying, into the penetrating unpleasant odour of the drug. This 

 change is due to the action of an enzyme, and may be prevented by 

 boiling the root previous to drying it. 



The student should observe 



(a) The colour and odour of the drug, 



(b) The short, erect rhizome surrounded by numerous roots, 



(c) The characters of the section of the rhizome as given above. 



Constituents. The principal constituent of valerian root is the 

 volatile oil which is contained in the sub-epidermal layer of cells in 

 the root, not in isolated oil-cells or glands. Good valerian root yields 

 about 1 per cent, of volatile oil, one of the constituents of which is 

 bornyl isovalerianate. This constituent is gradually decomposed 

 by an enzyme present, yielding free isovalerianic acid, an oily liquid 

 possessing an unpleasant odour of valerian ; to this body the un- 

 pleasant odour of valerian root is to be ascribed, and its gradual 

 production from bornyl isovalerianate explains the development of 

 the odour as the root dries. 



Valerian root also contains two alkaloids, chatinine and valerianine, 

 which require further investigation. 



Chevalier (1907) found in the fresh rhizome an alkaloid, a glucoside, 

 and a resin, all of which were physiologically active, and considered 

 that the fresh root was preferable from a medicinal point of view to 

 the dry, the reason being that the bornyl isovalerianate was present 

 as such. 



