History—Hyoscyamus, under which name it is probable the nearly allied South European species, H. albus L., was generally intended, was medicinal among the ancients, and particularly commended by Dioscorides.
In Europe, henbane has been employed from remote times. Benedictus Crispus, archbishop of Milan, in a work written shortly before a.d. 681, notices it under the name of Hyoscyamus and Symphoniaca.[1695] In the 10th century, its virtues were particularly recorded by Macer Floridus[1696] who called it Jusquiamus.
Frequent mention is made of it in the Anglo-Saxon works on medicine of the 11th century,[1697] in which it is called Henbell, and sometimes Belene, the latter word perhaps traceable in βιλινουντία, which Dioscorides[1698] gives as the Gallic designation of the plant. In the 13th century henbane was also used by the Welsh “Physicians of Myddvai.”
The word Hennibone, with the Latin and French synonyms Jusquiamus and Chenille, occurs in a vocabulary of the 13th century; and Hennebane in a Latin and English vocabulary of the 15th century.[1699] In the Arbolayre, a printed French herbal of the 15th century,[1700] we find the plant described as Hanibane or Hanebane with the following explanation—“Elle est aultrement appeler cassilago et aultrement simphoniaca. La semence proprement a nom jusquiame ou hanebane, et herbe a nom cassilago....” Both Hyoscyamus and Jusquiamus are from the Greek Ὑοσκύαμος, i.e. Hog-bean.
Though a remedy undeniably potent, henbane in the first half of the last century had fallen into disuse. It was omitted from the London pharmacopœias of 1746 and 1788, and restored only in 1809. Its re-introduction into medicine was chiefly due to the experiments and recommendations of Störck.[1701]
During the middle ages the seeds and roots of henbane were also much used.
Description—The stems of henbane, whether of the annual or biennial form, are clothed with soft, viscid, hairy leaves, of which the upper constitute the large, sessile, coarsely toothed bracts of the unilateral flower-spike. The middle leaves are more toothed and subamplexicaul. The lower leaves are stalked, ovate-oblong, coarsely dentate, and of large size. The stems, leaves, and calyces of henbane are thickly beset with long, soft, jointed hairs; the last joint of many of these hairs exudes a viscid substance occasioning the fresh plant to feel clammy to the touch. In the cultivated plant, the hairiness diminishes.
After drying, the broad light-coloured midrib becomes very conspicuous, while the rest of the leaf shrinks much and acquires a greyish green hue. The drug derived from the flowering plant as found in commerce is usually much broken. The fœtid, narcotic odour of the fresh leaves is greatly diminished by drying. The fresh plant has but little taste.
Dried henbane is sold under three forms, which are not however generally distinguished by druggists. These are 1. Annual plant, foliage and green tops. 2. Biennial plant, leaves of the first year. 3. Biennial plant, foliage and green tops. The third form is always regarded as the best, but no attempt has been made to determine with accuracy the relative merits of the three sorts.
Chemical Composition—Hyoscyamine, the most important among the constituents of henbane, was obtained in an impure state by Geiger and Hesse in 1833. Höhn in 1871 first isolated it from the seeds, which are far richer in it than the leaves.[1702] The seeds are deprived of the fatty oil (26 per cent.) and treated with spirit of wine containing sulphuric acid, which takes out the hyoscyamine in the form of sulphate. The alcohol is then evaporated and tannic acid added; the precipitate thus obtained is mixed with lime and exhausted with alcohol. The hyoscyamine is again converted into a sulphate, the aqueous solution of which is then precipitated with carbonate of sodium, and the alkaloid dissolved by means of ether. After the evaporation of the ether, hyoscyamine remains as an oily liquid which after some time concretes into wart-like tufted crystals, soluble in benzol, chloroform, ether, as well as in water. Höhn and Reichardt assign to hyoscyamine the formula C₁₅H₂₃O₃. The seeds yield of it only 0·05 per cent.