Rhamnus Frangula (LINN.)
Family: N.O. Rhamnaceae
Synonyms: Black Dogwood. Frangula Bark.
Part Used: Bark
Habitat: The Alder Buckthorn is a slender shrub, widely distributed
over Europe and northern Asia, and found in woods and thickets throughout
England, though rare in Scotland.
Description
| Cultivation
| Parts Used Medicinally
Constituents
| Medicinal Action
and Uses
| Preparation
In place of the violently-acting juice of the berries of the Common
Buckthorn, a fluid extract prepared from the bark of the closely allied and
milder Alder Buckthorn or Black Alder (Rhamnus Frangula, Linn.) has been
proved a very satisfactory substitute. Frangula bark is official both in the
United States and the British Pharmacopoeia. Its use has been, however, somewhat
neglected and the much advertized Cascara Sagrada (R. purshianus) has
greatly taken its place, though itis a less agreeable aperient.
¶ Description.
It is generally about the same
size as the Common Buckthorn, but is distinguished from it by its less bushy and
more tree-like habit, by the absence of thorns on its branches and by its larger
and entire, not toothed, feather-veined leaves, which are all arranged
alternately on the stem, none opposite to one another. The flowers are produced
not only from the wood of the preceding year, but also on the shoots of the
current year, and have a five-parted calyx, while that of the Common Buckthorn
is four-cleft. They bloom in May and are of an inconspicuous green. Their fruit,
which is ripe in September, is not unlike that of the Common Buckthorn, but the
berry has only two, or at most three, roundish, angular seeds, instead of four.
Bees are likewise constant visitors of the flowers of this species, and goats
eat the leaves voraciously.
It grows as a rule in leaf-mould in woods comparatively free from lime.
The bark and leaves of the Alder Buckthorn yield a yellow dye much used in
Russia; when mixed with salts of iron it turns black. The berries, when unripe,
afford a good green colour, readily taken by woollen stuffs; when ripe, they
give various shades of blue and grey.
After removal of the bark from the stem and branches, the wood of this shrub
is used for making charcoal, yielding a very light, inflammable kind, and being
on that account preferred to that of almost any other tree by gunpowder makers,
who name it 'Black Dogwood.' In Germany, for the same reason, it is called Pulverholz
('powder-wood').
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¶ Cultivation.
Frangula bark is usually
collected from wild shrubs, but this Buckthorn can readily be cultivated. The
seeds should be sown as soon as ripe, not kept till the following spring. The
seedlings should be kept free from weeds, and in the autumn planted in the
nursery in rows 2 feet asunder and 1 foot distant in the rows. Stock may also be
increased by layers and cuttings, though propagation by seedling plants is
preferable.
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¶ Part Used
Medicinally. The dried bark
collected from the young trunk and moderately-sized branches in early summer and
kept at least one year before being used. It is stripped from the branches and
dried either on sunny days, out of doors, in halfshade, or by artificial heat,
on shelves or trays, in a warm, well-ventilated room.
The dried bark varies considerably in appearance, according to the age of the
branch or stem from which it has been taken. Young bark, which is to be
preferred, occurs in narrow, single or double quills and is of papery texture,
about 1/25 inch thick. It is of a greyish or blackish-brown colour outside, with
numerous small, whitish corky warts. When gently scraped, the inner layers are
seen to be crimson in colour. The inner surface of the bark is smooth, of a
pale, yellowish brown and very finely striated. The fracture is short. Older
bark is rougher externally, thicker and usually in single quills or channelled
pieces.
The bark is nearly inodorous; its taste is pleasant, sweetish and slightly
bitter. When masticated, it colours the saliva yellow.
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¶ Constituents.
The chemical constituents of
Frangula Bark, especially those to which the laxative properties are due, are
but imperfectly known. A yellow, crystalline glucoside, Frangulin has been
isolated from it. Emodin is present in old bark; this principle is also present
in rhubarb root; it is allied to Chrysophane, and is said to result from the
glucosic fermentation of Frangulin or Frangulic acid, and to its presence the
drug owes its purgative action. Possibly other glucosides are also present and
contribute to the laxative action, but the evidence in favour of this assumption
is not conclusive. Two resins, resinous bitter matter and a little tannic acid
are likewise present in the bark.
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¶ Medicinal Action
and Uses. Tonic, laxative,
cathartic.
Dried seasoned bark from one to twoyears old alone should be used, as the
freshlystripped bark acts as an irritant poison on the gastro-intestinal canal.
The action of the bark becomes gradually less violent when kept for a length of
time and more like that of rhubarb.
It is used as a gentle purgative in cases of chronic constipation and is
principally given in the form of the fluid extract, in small doses, repeated
three or four times daily, a decoction of 1 OZ. of the bark in 1 quart of water
boiled down to a pint, may also be taken in tablespoonful doses.
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¶ Preparation.
Fluid extract, 1/2 to 2 drachms.
This milder English Buckthorn acts likewise as a tonic to the intestine and
is especially useful for relieving piles.
Lozenges of the Alder Buckthorn are dispensed under the name of
'Aperient
Fruit Lozenges.'
The juice of the berries, though little used, is aperient without being
irritating.
Country people used to take the bark boiled in ale for jaundice.
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Reprinted from "A
Modern Herbal" (1931)
Mrs. M. Grieve, Edited by Mrs. C.F. Leyel
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