_Henbane Leaves_; F. _Feuilles de Jusquiame_; G. _Bilsenkraut_.
=Botanical Origin=—_Hyoscyamus niger_ L., a coarse, erect herb, with
soft, viscid, hairy foliage of unpleasant odour, pale yellowish flowers
elegantly marked with purple veins, and 5-toothed bottle-shaped calyx.
It is found throughout Europe from Portugal and Greece to Central
Norway and Finland, in Egypt, Asia Minor, the Caucasus, Persia, Siberia
and Northern India. As a weed of cultivation it now grows also in North
America[1693] and Brazil. In Britain it occurs wild, chiefly in waste
places near buildings; and is cultivated for medicinal use.
Henbane exists under two varieties, known as _annual_ and _biennial_,
but scarcely presenting any other distinctive character.
_Biennial Henbane_ (_Hyoscyamus niger_ var. α. _biennis_) is most
esteemed for pharmaceutical preparations. It is raised by seed, the
plant producing the first year only a rosette of luxuriant stalked
leaves, 12 or more inches in length. In the second, it throws up a
flower stem of 2 to 3 feet in height, and the whole plant dies as the
fruit matures.
_Annual Henbane_ (_H. niger_ var. β. _annua_, vel _agrestis_) is a
smaller plant, coming to perfection in a single season. It is the usual
wild form, but it is also grown by the herbalists.[1694]
=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_.
[1693] It had become naturalized in North America prior to 1672,
as we find it mentioned by Josselyn in his _New England’s Rarities
discovered_ (Lond. 1672) among the plants “sprung up since the English
planted and kept cattle in New England.”
[1694] _Pharm. Journ._ i. (1860) 414.
[1695] S. de Renzi, _Collectio Salernitana_, Napoli, i. (1852) 74. 84.
[1696] _De Viribus Herbarum_, edited by Choulant, Lips. 1832. 108.
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.
[1697] _Leechdoms etc. of Early England_, iii. (1866) 313.
[1698] Lib. iv. c. 69. (ed. Sprengel).
[1699] Wright, _Volume of Vocabularies_, 1857. 141. 265.
[1700] See p. 148, note 3, also Brunet, _Manuel du Libraire_, i. (1860)
377.
[1701] See p. 459, note 5.
=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.
Hyoscyamine is easily decomposed by caustic alkalis. By boiling with
baryta in aqueous solution, it is split into _Hyoscine_, C₆H₁₃N, and
_Hyoscinic Acid_, C₉H₁₀O₃. The former is a volatile oily liquid of a
narcotic odour and alkaline reaction. By keeping it over sulphuric
acid it crystallizes and also yields crystallized salts; hyoscine may
be closely allied to conine, C₈H₁₅N. Hyoscinic acid, a crystallizable
substance having an odour resembling that of empyreumatic benzoic
acid.[1703] It melts, according to Höhn, at 105°; tropic acid (see p.
457), melting at 118°, agrees so very nearly with hyoscinic acid that
further researches will probably prove these acids to be identical.
Another process for extracting hyoscyamine is due (1875) to Thibaut. He
removes by bisulphide of carbon the fatty oil from the powdered seeds,
and exhausts them with alcohol slightly acidulated by tartaric acid.
The alcohol being distilled off, the author precipitates the alkaloid
by means of a solution containing 6 per cent. of iodide of potassium
and 3 per cent. iodine. By decomposing the precipitate with sulphurous
acid, hydroiodic acid and sulphate of hyoscyamine are formed. The
latter is dried up at 35° with magnesia and the hyoscyamine extracted
by alcohol or chloroform. The crystals melt at 90°. Thibaut found the
alkaloid thus prepared from seeds differing from that yielded by the
leaves, the latter having a somewhat strong odour.
Attfield[1704] has pointed out that extract of henbane is rich in
nitrate of potassium and other inorganic salts. In the leaves, the
amount of nitrate is, according to Thorey,[1705] largest before
flowering, and the same observation applies to hyoscyamine.
=Uses=—Henbane in the form of tincture or extract is administered
as a sedative, anodyne or hypnotic. The impropriety of giving it in
conjunction with free potash or soda, which render it perfectly inert,
has been demonstrated by the experiments of Garrod.[1706] Hyoscyamine,
like atropine, powerfully dilates the pupil of the eye.
[1702] From the experiments of Schoonbroodt (1868), there is reason
to believe that the active principle of henbane can be more easily
extracted from the _fresh_ than from the _dried_ plant.
[1703] I have had the opportunity of examining the above substances as
prepared by the said chemists.—F. A. F. July 1871.
[1704] _Pharm. Journ._ iii. (1862) 447.
[1705] Wiggers and Husemann, _Jahresbericht_, 1869. 56.
[1706] _Pharm. Journ._ xvii. (1858) 462; xviii. (1859) 174.
=Substitutes=—_Hyoscyamus albus_ L., a more slender plant than
_H. niger_ L., with stalked leaves and bracts, a native of the
Mediterranean region, is sometimes used in the south of Europe as
medicinal henbane. _H. insanus_ Stocks, a plant of Beluchistan, is
mentioned in the _Pharmacopœia of India_ as of considerable virulence,
and sometimes used for smoking.