_Cortex Cuspariæ_; _Angostura Bark_, _Cusparia Bark_, _Carony Bark_; F.
_Ecorce d’Angusture de Colombie_; G. _Angostura-Rinde_.
=Botanical Origin=—_Galipea Cusparia_ St. Hilaire (_G. officinalis_
Hancock, _Bonplandia trifoliata_ Willd., _Cusparia trifoliata_ Engler
1874, _Flora Brasil_. 113), a small tree, 12 to 15 feet high, with a
trunk 3 to 5 inches in diameter, growing in abundance on the mountains
of San Joaquin de Caroni in Venezuela, between 7° and 8° N. lat., also
according to Bonpland[419] near Cumana. According to Hancock,[420] who
was well acquainted with the tree, it is also found in the Missions of
Tumeremo, Uri, Alta Gracia, and Cupapui, districts lying eastward of
the Caroni and near its junction with the Orinoko. The bark is brought
into commerce by way of Trinidad.
=History=—Angostura Bark is said to have been used in Madrid by
Mutis as early as 1759[421] (the year before he left Spain for South
America,) but it was certainly unknown to the rest of Europe until
much later. Its real introducer was Brande, apothecary to Queen
Charlotte, and father of the distinguished chemist of the same name,
who drew attention to some parcels of the bark imported into England
in 1788.[422] In the same year a quantity was sent to a London drug
firm by Dr. Ewer of Trinidad, who describes it[423] as brought to that
island from Angostura by the Spaniards. The drug continued to arrive
in Europe either by way of Spain or England, and its use was gradually
diffused. In South America it is known as _Quina de Caroni_ and
_Cascarilla del Angostura_.
=Description=—The bark occurs in flattish or channelled pieces, or
in quills rarely as much as 6 inches in length and mostly shorter.
The flatter pieces are an inch or more in width and ⅛ of an inch in
thickness. The outer side of the bark is coated with a yellowish-grey
corky layer, often soft enough to be removeable with the nail, and
then displaying a dark brown, resinous under surface. The inner side
is light brown with a rough, slightly exfoliating surface indicating
close adhesion to the wood, strips of which are occasionally found
attached to it; the obliquely cut edge also shows that it is not very
easily detached. The bark has a short, resinous fracture, and displays
on its transverse edge sharply defined white points, due to deposite of
oxalate of calcium. It has a bitter taste and a nauseous musty odour.
[419] Humboldt, _Reise in die Aequinoctialgegenden des neuen
Continents_, iv. (Stuttgart, 1860), 252.—Humboldt and Bonpland in 1804
obtaining, from the Caroni river, flowering branches of the “_Cuspa_”
(_l. c._ 1. 300) or “_Cuspare_,” as it is called by the Indians,
believed it to constitute a new genus. In 1824 St. Hilaire ascertained
it to belong to the genus Galipea.
The tree is figured in Bentley and Trimen, _Med. Plants_, part 26
(1877).
[420] _Observations on the Orayuri or Angustura Bark Tree_,—_Trans.
of Medico-Botanical Society_, 1827-29.—Hancock endeavoured to prove
his tree distinct from _G. Cusparia_ St. Hil., but Farre and Don who
subsequently examined his specimens decided that the two were the
same. With the assistance of Prof. Oliver, I also have examined (1871)
Hancock’s plant, comparing it with his figure and other specimens,
and have arrived at the conclusion that it is untenable as a distinct
species.—D. H.
[421] Martiny, _Encyklopädie_, i. (1843) 242.
[422] Brande, _Experiments and Observations on the Angustura Bark_.
1791. 2nd ed. 1793.
[423] _London Med. Journ._ x. (1789) 154.
=Microscopic Structure=—The most striking peculiarity is the great
number of oil-cells scattered through the tissue of the bark. They
are not much larger than the neighbouring parenchymatous cells, and
are loaded with yellowish essential oil or small granules of resin.
Numerous other cells contain bundles of needle-shaped crystals of
oxalate of calcium or small starch granules. The liber exhibits bundles
of yellow fibres, to which the foliaceous fracture of the inner bark
is due. The structure of the bark under notice has been very minutely
described and figured by Oberlin and Schlagdenhauffen.[424]
=Chemical Composition=—Angostura bark owes its peculiar odour to an
essential oil which it was found by Herzog[425] to yield to the extent
of ¾ per cent. It is probably a mixture of a hydrocarbon (C₁₀H₁₆)
with an oxygenated oil. Its boiling point is 266° C. Oberlin and
Schlagdenhauffen obtained 0·19 per cent. of the oil, and found it to
be slightly dextrogyre; it assumes a fine red colour when shaken with
aqueous ferric chloride, and turns yellow with concentrated sulphuric
acid.
[424] _Journ. de Pharm. et de Chimie_, 28 (1877), 226; plates I, II,
III. The bark is also figured by Berg, _Anatomischer Atlas_, Tab. 37.
[425] _Archiv d. Pharm._ xcii. (1858) 146.
The bitter taste of the bark is attributed to a substance pointed out
in 1833 by Saladin and named _Cusparin_. It is said to be crystalline,
neutral, melting at 45° C., soluble in alcohol, sparingly in water,
precipitable by tannic acid. The bark is stated to yield it to the
extent of 1·3 per cent. Herzog endeavoured to prepare it but without
success, nor have Oberlin and Schlagdenhauffen met with it. The latter
chemists, on the other hand, isolated an alkaloid _Angosturine_
C₁₀H₄₀NO₁₄. It is in thin prisms, melting at 85° and yielding a
crystallized chlorhydrate or sulphate. Angosturine turns red when
touched with concentrated sulphuric acid, or green if nitric acid or
iodic acid, or other oxydizing substances, have been previously mixed
with the sulphuric acid. The alcoholic solution of the alkaloid is of
decidedly alkaline reaction. A cold aqueous infusion of angostura bark
yields an abundant red-brown precipitate with ferric chloride. Thin
slices of the bark are not coloured by solution of ferrous sulphate, so
that tannin appears to be absent.
=Uses=—Angostura bark is a valuable tonic in dyspepsia, dysentery and
chronic diarrhœa, but is falling into disuse.
=Adulteration=—About the year 1804, a quantity of a bark which proved
to be that of _Strychnos Nux Vomica_ reached Europe from India, and
was mistaken for Cusparia. The error occasioned great alarm and
some accidents, and the use of angostura was in some countries even
prohibited. The means of distinguishing the two barks (which are not
likely to be again confounded) are amply contained in the above-given
descriptions and tests, and at length pointed out by Oberlin and
Schlagdenhauffen. They also described the bark of _Esenbeckia
febrifuga_ Martius (_Evodia febrifuga_ Saint Hilaire), a Brazilian
tree belonging to the same natural order. Maisch[426] was the first
to draw attention to this “_new false Angostura bark_.” It is at once
distinguished by being devoid of aromatic properties; its taste is
purely bitter.