_Herba Chirettæ vel Chiraytæ_; _Chiretta or Chirayta_.
=Botanical Origin=—_Ophelia[1619] Chirata_ Grisebach (_Gentiana
Chirayita_ Roxb.), an annual herb of the mountainous regions of
Northern India from Simla through Kumaon to the Murung district in
South-eastern Nepal.
=History=—Chiretta has long been held in high esteem by the Hindus, and
is frequently mentioned in the writings of Susruta. It is called in
Sanscrit _Kirāta-tikta_, which means the _bitter plant of the Kirātus_,
the Kirātas being an outcast race of mountaineers in the north of
India. In England, it began to attract some attention about the year
1829; and in 1839 was introduced into the Edinburgh Pharmacopœia. The
plant was first described by Roxburgh in 1814.
[1617] Grisebach (_Die Vegetation der Erde_, i. 1872. 223) gives very
interesting particulars relating to the area of growth of _Gentiana
purpurea_, _G. punctata_ and _G. pannonica_. He is decidedly of the
opinion that they are distinct species.
[1618] In Norway it is, strange to say, called sweetroot, “_Sötrot_,”
according to Schübeler, _Pflanzenwelt Norwegens_, 1873-1875, p. 259.
[1619] Ὀϕέλλειν, to bless, in allusion to the medical virtues of the
herb.—Fig. in Bentley and Trimen, _Med. Plants_, part 7 (1876).
Chiretta was regarded by Guibourt as the _Calamus aromaticus_ of the
ancients, but the improbability of this being correct was well pointed
out by Fée[1620] and by Royle, and is now generally admitted.
=Description=—The entire plant is collected when in flower, or more
commonly when the capsules are fully formed, and tied up with a slip
of bamboo into flattish bundles of about 3 feet long,[1621] each
weighing when dry from 1½ to 2 lb. The stem, ²/₁₀ to ³/₁₀ of an inch
in thickness, is of an orange-brown, sometimes of a dark purplish
colour; the tapering simple root, often much exceeding the stem in
thickness, is 2 to 4 inches long and up to ½ an inch thick. It is
less frequently branched, but always provided with some rootlets.
In stronger specimens, the root is somewhat oblique or geniculate;
perhaps the stem is in this case the product of a second year’s growth
and the plant not strictly annual. Each plant usually consists of a
single stem, yet occasionally two or more spring from a single root.
The stem rises to a height of 2 to 3 feet, and is _cylindrical in its
lower and middle portion_, but bluntly quadrangular in its upper,
the four edges being each marked with a prominent decurrent line,
as in _Erythræa Centaurium_ and many other plants of the order. The
decussate ramification resembles that of other gentians; its stems
are jointed at intervals of 1½ to 3 or 4 inches, bearing opposite
semi-amplexicaul leaves on their cicatrices. The stem consists in its
lower portion of a large woody column, coated with a very thin rind,
and enclosing a comparatively large pith. The upper parts of the stem
and branches contain a broad ring of thick-walled woody parenchyme. The
numerous slender axillary and opposite branches are elongated, and thus
constitute a dense umbellate panicle. They are smooth and glabrous, of
a greenish or brownish grey colour.
The leaves are ovate-acuminate, cordate at the base, entire, sessile,
the largest 1 inch or more in length, 3-to 5-or 7-nerved, the midrib
being strongest. At each division of the panicle there are two small
bracts. The yellow corolla is rotate, 4-lobed, with glandular pits
above the base; the calyx is one-third the length of the petals, which
are about half an inch long. The one-celled, bivalved capsule contains
numerous seeds.
The flowers share the intense bitterness of the whole drug. The wood of
stronger stems is devoid of the bitter principles.
=Chemical Composition=—A chemical examination of chiretta has been made
at our request under the direction of Professor Ludwig of Jena, by his
assistant Mr. Höhn. The chief results of this careful and elaborate
investigation may be thus described.[1622]
Among the bitter principles of the drug, _Ophelic Acid_, C₁₃H₂₀O₁₀,
occurs in the largest proportion. It is an amorphous, viscid, yellow
substance, of an acidulous, persistently bitter taste, and a faint
gentian-like odour. With basic acetate of lead, it produces an abundant
yellow precipitate. Ophelic acid does not form an insoluble compound
with tannin; it dissolves in water, alcohol and ether. The first
solution causes the separation of protoxide of copper from an alkaline
tartrate of that metal.
[1620] _Cours d’Histoire nat. pharmaceutique_, ii. (1828) 395.
[1621] The other kinda of chiretta to be named presently are usually
much shorter.
[1622] For full details, see _Archiv der Pharmacie_, 189 (1869) 229.
A second bitter principle, _Chiratin_, C₂₆H₄₈O₁₅, may be removed by
means of tannic acid, with which it forms an insoluble compound.
Chiratin is a neutral, not distinctly crystalline, light yellow,
hygroscopic powder, soluble in alcohol, ether and in warm water. By
boiling hydrochloric acid, it is decomposed into _Chiratogenin_,
C₁₃H₂₄O₃, and ophelic acid. Chiratogenin is a brownish, amorphous
substance, soluble in alcohol but not in water, nor yielding a tannic
compound. No sugar is formed in this decomposition.
These results exhibit no analogy to those obtained in the analysis
of the European gentians. Finally, Höhn remarked in chiretta a
crystallizable, tasteless, yellow substance, but its quantity was so
minute that no investigation of it could be made.
The leaves of chiretta, dried at 100° C., afforded 7·5 per cent. of
ash; the stems 3·7; salts of potassium and calcium prevailing in both.
=Uses=—Chiretta is a pure bitter tonic, devoid of aroma and
astringency. In intense bitterness it exceeds gentian, _Erythræa_ and
other European plants of the same order. It is much valued in India,
but is not very extensively used in England, and not at all on the
Continent. It is said to be employed when cheap, in place of gentian,
to impart flavour to the compositions now sold as _Cattle Foods_.
=Substitutes and Adulteration=—Some other species of _Ophelia_, namely,
_O. angustifolia_ Don, _O. densifolia_ Griseb., _O. elegans_ Wight,
_O. pulchella_ Don, and _O. multiflora_ Dalz, two or three species of
_Exacum_, besides _Andrographis paniculata_ Wall., are more or less
known in the Indian bazaars by the name of _Chiretta_[1623] and possess
to a greater or less degree the bitter tonic properties of that drug.
Another _Gentianacea_, _Slevogtia orientalis_ Griseb., is called _Chota
Chiretta_, i.e. _small chiretta_. It would exceed due limits were we
to describe each of these plants: we have therefore given a somewhat
detailed description of the true chiretta, which will suffice for its
identification. We have frequently examined the chiretta found in the
English market, but have never met with any other than the legitimate
sort.[1624] Bentley noticed in 1874 the substitution of _Ophelia
angustifolia_, which he found to be by far less bitter than true
chiretta.