Source, Etc

The deadly nightshade, or belladonna, Atropa Belladonna, Linne (N.O. Solanaceoe), is a tall branching herb, attaining a height of 2 metres. It is widely distributed over central and southern Europe; in England it is confined chiefly to the southern counties, but it is cultivated in Bedfordshire, Hertfordshire, and elsewhere, and is grown for medicinal use in Germany also.

Belladonna possesses a stout, branching, tap root which for medicinal use should be collected in the autumn when about three or four years old, cut into pieces, and carefully dried. The commercial drug, much of which has been imported from Germany, though probably collected in Hungary, is often of inferior quality.

Description

Good root as found in commerce, occurs in pieces varying from 15 to 20 cm. in length, and from 1 to 2 cm. in diameter. It is of a pale greyish brown colour, finely wrinkled longitudinally, usually cylindrical or gradually tapering, and often crowned with the remains of hollow aerial stems. Sometimes the roots are cut longitudinally to facilitate drying. They break with a short fracture, and should be whitish and starchy internally. The section exhibits a greyish bark separated by a dark line (cambium) from a whitish central portion (wood) in which, especially near the cambium ring, dark groups of vessels and fibres are scattered; these groups, however, seldom exhibit more than an indistinctly radiate arrangement except close to the crown of the root, where one or more rings of radiate yellowish wood may be found, the root passing imperceptibly into rhizome. The bark is not fibrous, and adheres closely to the wood. Most of the parenchymatous cells of both bark and wood contain small compound starch-grains, and some of them are filled with numerous very minute (sandy) crystals of calcium oxalate; these characters, visible only under the microscope, serve as additional means of identifying belladonna root.

Old roots become woody, and may then exhibit a prominently radiate structure, whilst roots gathered in spring contain sugar and but little starch, and hence show a shrunken outer surface and a dark, spongy interior. In both cases the drug is believed to contain less alkaloid than the young root collected in the autumn and possessing the characters given though roots that are dark internally and not starchy often contain high percentages of alkaloid.

Notwithstanding the fact that the preparations of belladonna root are standardised, the official description is framed so as to exclude such old or partially exhausted roots.

The root has an odour recalling liquorice root, and a slightly bitter taste.

Fig. 186.   Belladonna root, a, portion of young root, natural size; b, transverse section of the same, magnified; c, transverse section of the upper part of the root, magnified. (Holmes).

Fig. 186. - Belladonna root, a, portion of young root, natural size; b, transverse section of the same, magnified; c, transverse section of the upper part of the root, magnified. (Holmes).

The student should carefully observe

(a) The firm, plump appearance of typical belladonna root,

(b) The short, mealy fracture,

(c) The dark cambium line, and distribution of the groups of vessels and fibres; and should compare the root with

(i) Elecampane root, in which oil glands are present, and the groups of vessels inconspicuous, (ii) Scammony root (small pieces), which have a very characteristic structure,

(iii) Marshmallow root, which has a radiate wood, in which scattered groups of vessels are not visible, and a fibrous bark.

Constituents

The principal constituent of belladonna root is the alkaloid hyoscyamine which appears to be accompanied by a little atropine, although it is possible that the atropine found has been produced from hyoscyamine during the process of extraction, a change which is readily effected. Traces of scopolamine appear also to be present, but belladonnine and apoatropine, which are found in the mother liquors from which the other alkaloids have been crystallised, probably do not exist as such in the root, but are formed during the various manipulations in the course of their isolation (compare p. 45). The root also contains β-methyl-aesculetin (chrysatropic acid, scopoletin), a crystalline fluorescent principle, widely distributed throughout the natural order Solanaceoe, and found also in gelsemium rhizome and a number of other drugs.

The total amount of alkaloid that the root contains varies as a rule between 0.4 and 0.6 per cent., but may occasionally rise to 1.0 per cent. (Cripps). Gerrard has shown that the plant is more active when about four years old than when younger, and that the wild plant is rather richer in alkaloid than the cultivated, while Schmidt's experiments indicate that the roots of young plants contain more alkaloid than those of old plants. The Pharmacopoeia therefore directs the root to be collected in the autumn, and excludes old roots by the limitation of the size and by the description of the transverse section.

Uses

Belladonna acts as a local anaesthetic and anodyne, and is often applied as such externally. Internally it is given to check the sweating in phthisis, as a sedative to the respiratory nerves, to relieve spasmodic cough, and in numerous other cases.

Adulterants

Scopola Rhizome. The rhizome of Scopola car-niolica, Jacquin (N.O. Solanaceoe), is not unfrequently found in the belladonna root imported from Germany. The plant grows in the Carpathian Mountains and other parts of Austro-Hungary. It produces a horizontal rhizome from which aerial stems from 30 to 60 cm. high arise bearing leaves which resemble belladonna leaves but are thinner, more lanceolate in shape, and taper more towards the base (compare p. 46). The rhizome, which is collected in large quantities and forms an important source of the alkaloids hyoscyamine, atropine, and scopolamine, may attain 10 cm. or more in length and about 2 cm. in thickness. It is nearly black in colour and tortuous, and bears on the upper surface numerous large depressed stem-scars. It contains hyoseyamine, scopolamine, and possibly also atropine, the total alkaloid (0.6 to 0.7 per cent.) somewhat exceeding in amount that present in belladonna root.

Japanese Belladonna, Scopola Japonica, Maximowicz, closely resembles scopola rhizome.

Indian Belladonna Root. Considerable quantities of belladonna root have recently been imported from India, the bulk having been collected in Kashmir from wild plants of Atropa lutescens, Jac-quemont, which is closely allied to A. Belladonna. Indian belladonna root closely resembles the European, but may be distinguished by the section, which exhibits a radiate wood even in the small roots. The drug has been stated to contain 0.7 per cent. of alkaloid, but it is doubtful whether this is entirely mydriatic Solanaceous alkaloid. Phytolacca Root. The root of Phytolacca decandra, Linne (N.O. Phytolaccaceoe), a plant indigenous to North America but naturalised in southern Europe, has been used to adulterate belladonna. It may, however, readily be detected by the transverse section which exhibits several concentric rings of wood bundles, in consequence of which large roots readily fissure longitudinally. It contains abundant acicular crystals of calcium oxalate in place of the sandy calcium oxalate of belladonna. As it attains a much larger size than belladonna root it is often cut into pieces for admixture. It contains a resinoid substance, phytolaccin, and has a purgative action.