RADIX GENTIANÆ.
Gentian Root; F. Racine de Gentiane; G. Enzianwurzel.
Botanical Origin—Gentiana lutea L., a handsome perennial herb, growing 3 feet high, indigenous to open grassy places on the mountains of Middle and Southern Europe. It occurs in Portugal, Spain, the Pyrenees, in the islands of Sardinia and Corsica, in the Apennines, the mountains of Auvergne, the Jura, the Vosges, the Black Forest, and throughout the chain of the Alps as far as Bosnia and the Danubian Principalities. Among the mountains of Germany, it is found on the Suabian Alps near Würzburg, and here and there in Thuringia, but not further north, nor does it occur in the British Islands.
History—The name Gentiana is said to be derived from Gentius, a king of the Illyrians, living b.c. 180-167, by whom, according to both Pliny and Dioscorides, the plant was noticed. Whether the species thus named was Gentiana lutea is doubtful. During the middle ages, gentian was commonly employed for the cure of disease, and as an antidote to poison. Tragus in 1552 mentions it as a means of diluting wounds, an application which has been resorted to in modern medical practice.
Description—The plant has a cylindrical, fleshy, simple root, of pale colour, occasionally almost as much as 4 feet in length by 1½ inches in thickness, producing 1 to 4 aerial stems.
The dried root of commerce is in irregular, contorted pieces, several inches in length, and ½ to 1 inch in thickness; the pieces are much wrinkled longitudinally, and marked transversely, especially in their upper portion, with numerous rings. Very often they are split to facilitate drying. They are of a yellowish-brown; internally of a more orange tint, spongy, with a peculiar, disagreeable, heavy odour, and intensely bitter taste. The crown of the root, which is somewhat thickened, is clothed with the scaly bases of leaves. The root is tough and flexible,—brittle only immediately after drying. We found it to lose in weight about 18 per cent.; by complete drying in a water-bath it regained 16 per cent. by being afterwards exposed to the air.
Microscopic Structure—A transverse section shows the bark separated by a dark cambial zone from the central column; the radial arrangement of the tissues is only obvious in the latter part. In the bark, liber-fibres are wanting; and in the centre there is no distinct pith. The fibro-vascular bundles are devoid of thick-walled ligneous prosenchyme; this may explain the consistence, and the short even fracture of the root. It is moreover remarkable on account of the absence both of starch and oxalate of calcium; the cells appear to contain chiefly sugar and a little fat oil.
Chemical Composition—The bitter taste of gentian is due to a substance called Gentiopicrin or Gentian-bitter, C₂₀H₃₀O₁₂. Several chemists, as Henry, Caventou, Trommsdorff, Leconte and Dulk have described the bitter principle of gentian in an impure state, under the name of Gentianin, but Kromayer in 1862 first obtained it in a state of purity. Gentiopicrin is a neutral body crystallizing in colourless needles, which readily dissolve in water. It is soluble in spirit of wine, but in absolute alcohol only when aided by heat; it does not dissolve in ether. A solution of caustic potash or soda forms with it a yellow solution. Under the influence of a dilute mineral acid, gentiopicrin is resolved into glucose, and an amorphous, yellowish-brown, neutral substance, named Gentiogenin. Fresh gentian roots yield somewhat more than ⅒ per cent. of gentiopicrin; from the dried root it could not be obtained in a crystallized state. The medicinal Tincture of Gentian, mixed with solution of caustic potash, loses its bitterness in a few days, probably in consequence of the destruction of the gentiopicrin.
Another constituent of gentian root is Gentianin or gentisin
 | CH₃ | |
| C₁₄H₁₀O₅ or (OH)₂C₆H₃·CO·C₆H₂ | O \ . | |
| O / |