_Radix Enulæ_, _Radix Helenii_; _Elecampane_;[1412] F. _Racine
d’Aunée_; G. _Alantwurzel_.
=Botanical Origin=—_Inula Helenium_ L.—This stately perennial plant
is very widely distributed, occurring scattered throughout the
whole of central and southern Europe, and extending eastward to the
Caucasus, Southern Siberia and the Himalaya. It is found here and there
apparently wild in the south of England and Ireland, as well as in
Southern Norway and in Finland (Schübeler).
Elecampane was formerly cultivated in gardens as a medicinal and
culinary plant, and in this manner has wandered to North America. In
Holland and some parts of England and Switzerland, it is cultivated on
a somewhat larger scale, most largely probably near Cölleda (see p.
377).
[1412] A corruption of _Enula Campana_, the latter word referring to
the growth of the plant in Campania (Italy).
=History=—The plant was known to the ancient writers on agriculture
and natural history, and even the Roman poets were acquainted with it,
and mention Inula as affording a root used both as a medicine and a
condiment. Vegetius Renatus, about the beginning of the 5th century,
calls it Inula Campana, and St. Isidore in the beginning of the 7th
names it as _Inula_, adding—“quam _Alam_ rustici vocant.” It is
frequently mentioned in the Anglo-Saxon writings on medicine current
in England prior to the Norman Conquest; it is also the “marchalan” of
the Welsh Physicians[1413] of the 13th century and was generally well
known during the middle ages. Not only was its root much employed as a
medicine, but it was also candied and eaten as a sweetmeat.
=Description=—For pharmaceutical use, the root is taken from plants
two or three years old; when more advanced, it becomes too woody. The
principle mass of the root is a very thick short crown, dividing below
into several fleshy branches of which the larger are an inch or two
in diameter, covered with a pale yellow bark, internally whitish, and
juicy. The smaller roots are dried entire; the larger are variously
sliced, which occasions them to curl up irregularly. When dried, they
are of a light grey, brittle, horny, smooth-fractured. Cut transversely
the young root exhibits an indistinct radiate structure, with a
somewhat darker cambial zone separating the thick bark from the woody
nucleus. The pith is not sharply defined, and is often porous and
hollow. In the older roots the bark is relatively much thinner, and
the internal substance is nearly uniform. Elecampane root has a weak
aromatic odour suggestive of orris and camphor, and a slightly bitter,
not unpleasant, aromatic taste.
=Microscopic Structure=—The medullary rays, both of the woody
column and the inner part of the bark (_endophlœum_), exhibit large
balsam-ducts. In the fresh root they contain an aromatic liquid, which
as it dries deposits crystals of helenin, probably derived from the
essential oil. The parenchymatous cells of the drug are loaded with
inulin in the form of splinter-like fragments, devoid of any peculiar
structure.
=Chemical Composition=—It was observed by Le Febvre, as early as 1660,
that when the root of elecampane is subjected to distillation with
water a crystallizable substance collects in the head of the receiver
from which it speedily passes on as the operation proceeds. Similar
crystals may also be observed after carefully heating a thin slice
of the root, and are even found as a natural efflorescence on the
surface of root that has been long kept. They can be extracted from the
root by means of alcohol and precipitated with water. Kallen (1874,
1876) showed that the crystals chiefly consist of the _anhydride_,
C₁₅H₂₀O₂, of _alantic acid_, melting at 66° C. The anhydride, which is
very little aromatic, can easily be sublimed, although it begins to
boil only at 275°, yet not without decomposition. Alantic anhydride
dissolves in caustic lye, but on saturating the solution with an acid,
alantic acid, C₁₅H₂₂O₃, separates. It is not present in the root.
The anhydride is accompanied by a small quantity of _Helenin_, C₆H₈O,
and _Alantcamphor_ (i.e. Elecampane-camphor). The crystals of helenin
have a slightly (?) bitterish taste, but no odour, and melt at 110°.
The camphor, occurring in but very small amount, has not yet been
analyzed; it agrees probably with the formula C₁₀H₁₆O; it melts at
64° C., and in taste and smell is suggestive of peppermint. It is
very difficult entirely to remove helenin from alantcamphor, these
substances being soluble to nearly the same extent in alcohol or ether.
By distilling the second of them with pentasulphide of phosphorus,
_Cymene_, C₁₀H₁₄, was obtained.
[1413] _Meddygon Myddfai_, p. 61. 284. 311 (see Appendix).
By distilling the root under notice with water, the alantic anhydride
is chiefly obtained, but impregnated with _Alantol_, C₁₀H₁₆O
(probably). The latter can be removed from the crystals by pressing
them between folds of bibulous paper. On submitting this again to
distillation, alantol is obtained as an aromatic liquid, boiling at
200°.
The substance most abundantly contained in elecampane root is _Inulin_,
discovered in it by Valentine Rose at Berlin in 1804. It has the same
composition as starch, C₆H₁₀O₅, but stands to a certain extent in
opposition to that substance, which it replaces in the root-system of
_Compositæ_. In living plants, inulin is dissolved in the watery juice,
and on drying is deposited within the cells in amorphous masses, which
in polarized light are inactive, and are not coloured by iodine. There
are various other characters, by which inulin differs from starch. Thus
for instance, inulin readily dissolves in about 3 parts of boiling
water; the solution is perfectly clear and fluid, not paste-like; but
on cooling deposits nearly all the inulin. The solution is levogyre and
is easily transformed into uncrystallizable sugar. With nitric acid,
inulin affords no explosive compound as starch does.
Sachs showed in 1864 that by immersing the roots of elecampane, or
_Dahlia variabilis_ or of many other perennial _Compositæ_, in alcohol
or glycerin, inulin may be precipitated in a crystalline form. Its
globular aggregates of needle-shaped crystals (“sphæro-crystals”)
then exhibit under the polarizing microscope a cross similar to that
displayed by starch grains.
The amount of inulin varies according to the season, but is most
abundant in the autumn. Of the various sources for it, the richest
appears to be elecampane. Dragendorff, who has made it the subject of a
very exhaustive treatise,[1414] obtained from the root in October not
less than 44 per cent., but in spring only 19 per cent.
In the roots of the _Compositæ_ inulin is accompanied, according to
Popp,[1415] by two closely allied substances, _Synanthrose_, C₁₂H₂₂O₁₁
+ H₂O, and _Inuloïd_, C₆H₁₀O₅ + H₂O. Synanthrose is soluble in dilute
alcohol, devoid of any rotatory power, and deliquescent. Inuloïd is
much more readily soluble in water than inulin. Both these substances
are probably present in elecampane.
Inulin is widely distributed in the perennial roots of compositæ, and
has also been met with in the natural orders Campanulaceæ, Goodenovieæ
(or Goodeniaceæ), Lobeliaceæ, Stylidieæ, and lastly by Kraus (1879) in
the root of _Ionidium Ipecacuanha_ St. Hilaire, Violaceæ; the formerly
so-called _Ipecacuanha alba lignosa_ (see p. 375, note 4).
=Uses=—Elecampane is an aromatic tonic, but as a medicine is now
obsolete. It is chiefly sold for veterinary practice. In France
and Switzerland (Neuchâtel), it is employed in the distillation of
_Absinthe_.
=Substitutes=—Dioscorides in speaking of _Costus_ root states that it
is often mixed with that of elecampane of Kommagene (north-western
Syria). The former, derived from _Aplotaxis[1416] auriculata_ DC. (_A.
Lappa_ Decaisne, _Aucklandia Costus_ Falconer), is remarkably similar
to elecampane both in external appearance and structure. Costus is an
important spice, incense and medicine in the east from the antiquity
down to the present day;[1417] it would be of great interest to examine
it chemically with regard to elecampane.
[1414] _Materialien zu einer Monographie des Inulins_, St. Petersburg,
1870. 141 pages—See also _Prantl’s_ paper on Inulin, as abstracted in
_Pharm. Journ._ Sept. 1871. 262.
[1415] Wiggers and Husemann, _Jahresbericht_ for 1870. 68.
[1416] Bentham and Hooker unite this plant with _Saussurea_.
[1417] See Cooke, _Pharm. Journ._ viii. (1877) 41; Flückiger, _ibid._
121.