Unorganised Drugs

PHR 243
PHARMACOGNOSY & MEDICINAL PLANTS (II)
Unorganised Drugs
Unorganised drugs are materials having a structre that is
fairly uniform throughout and are not composed of cells.
They are usally derived from prats of plants of animals by
some process of extraction, such as incision e.g., opium,
decoction e.g., agar, expression e.g., olive oil, or natural
secretions such as beeswax and myrrh.
Unorganised drugs are frequently solids, but such as oils
and balsams, are fluids. In their description, the morphological
terms are not applied and therefore the physical characters of
forms are used as, color, odor, fracture, solubilities in common
organic solvents and chemical tests, all of which are used in
their identification.
Unorganized drugs may be classified under headings
based upon their origin and nature, giving well characterized
groups, such as:
a) Latex e.g., opium
b) Dried juice e.g., Aloes
c) Extracts e.g., catechu
d) Saccharine substances e.g., Honey
e) Oil and fats e.g., castor oil and lard
f) Gums e.g., gum Acacia
g) Resins e.g., colophony
h) Waxes e.g., beeswax
i) Volatile oils e.g., cinnamon oil
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RESINS
Theses are natural or induced solid or semi- solid
exudations from plants or from insects feeding on plants. They
are characterised by being insoluble in water, mostly soluble in
alcohol or ether, often uncrystallisable, and softening or melting
at moderate heat forming sticky or adhesive fluid without
volatilization or decomposition. They range in specific gravity
from 0.9 to 1.25.
Ingnited in the air, they burn with a smoky flame, owing to the
high carbon content in their molecule. They are usually the
oxidized terpenes of the volatile oils of plants and owing to their
insolubility in water, have little taste.
Resins, when pure are usually transparent, when they
contain water, they are opaque, and and no longer hard and
brittle. They are non- conductors of electricity, but when rubbed
they become negatively electrified.
A clear distinction must be made between natural resins
and prepared resins. A natural resin is one which occur as an
exudation e.g. mastic. A prepared resin may be made by
extraction of the drug with alcohol, pouring the concentrated
alcoholic percolate into an excess of acidified water, collecting,
washing and drying the precipitate e.g. podophyllum and jalap
resin. A prepared resin may also be derived from a natural
oleoresin by driving off the volatile oil by steam distillation e.g.
colophony.
Careful distinction must be made between the above
classes of resins and the so called synthetic resins. The latter are
polymeric substances which are readily formed either by
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condensation or by addition of readily available common
chemicals. For example, phenol and formaldehyde interact
initially to produce o- and p- hydroxyl benzyl alcohols which
then condenseto yield a large series of phenol- formaldehyde
(Bakelite) resins.
Resin combination :
A – Oleoresins
Natural oleoresins are mixtures of volatile oils and resins
and therefore they are liquids or semi liquids substances
depending on the amount of the volatile present. Turpentine,
copaiba and canada balsam are examples of this group.
B- Gum – Resins
These are natural mixtures of gum and resin, usually
obtained as exudations from plants, as myrrh.
C- Oleo-gum- resin
Resin may occur in combination with volatile oil and gum
for example asafetida.
D- Glycoresins
Resin may be combined in a glycosidal way with sugars as
the resin of the convolvulaceae being called glycoresins which
are found in Ipomea, Jalap and podophylum.
E- Balsams
Are resinous substances that contain the aromatic balsamic
acids i.e. benzoic acid or cinnamic acid or both or esters of these
acide. Balsams usually contain small amount of volatile oil.
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A- RESINS
1- Colophony ةينوفلقلا
Colophony, (Resina colophonium Gallicum) is the residue
left after steam distillation of the volatile oil from the oleoresin
abtained from Pinus palustris and other species of pinus, family
pinaceae
Description
Colophony accurs in large compact, angular, brittle, glassy
pale amber to brownish- yellow masses, frequently covered with
a yellow powder, transparent in thin fragments, fracture glassy;
easily pulverisable to pale, almost white powder. It has faintly
terebinthinate odour and taste. Colophony is insoluble in water,
but soluble in alcohol, in chloroform, in ether, in benzene, in
carbon disulphide, in glacial acetic acid, in fixed and volatile
oils and in dilute solutions of sodium or potassium hydroxides.
It is partly soluble in light petroleum. Colophony is readily
fusible and burns with a heavy yellow smoke.
Constituents:
Colophony contains about 93% abietic acid; before
distillation the resin contains large amounts of d- and l- pimaric
acids. During distillation the d- pimaric acid is stable but the l-
from undergoes isomeric change in to abietic acid.
Test for identity:
1- to about 10 ml of a 1% solution of colophony in acetic
anhydride, add 1 drop of sulphuric acid; a bright purplish-
red color is produced, which rapidly change to violet.
2- Shake about 0.05gm of freshly powdered colophony with
5 ml of light petroleum, for few minutes and filter. Shake
the filterate with an equal volume of dilute copper acetate
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solution; the light petroleum layer assumes a bright
bluish- green color.
Uses
Colophony is used in pharmacy for the preparation of zinc
oxide and other adhesive plasters and ointments. Large
quantities of the darker grades are destructively distilled to yield
rosin spirit and rosin oil. The medium grades are largely used
for the manufacture of soap and the lighter grades for sealing
wax.
2- Guaiacum Resin – Resina Guaiaci
Plant Source: guaiacum resin is obtained from the heart wood
of Guaiacum officinale and Guaiacum sanctum, family
Zygophyllaceae.
Preparation of the resin ;
Gyaiacum wood chips are boiled in salt solution, when the resin
which melts at about 85°c may be more or less separated from
the wood.
Description:
Guaiacum resin occurs in large blocks or rounded tears
about 2-3 cm in diameter, often covered with a dull green
powder. The powder is grayish but become green on exposure
to light and air. The taste is slightly acrid and the odor is
aromatic especially when warmed.
Guaiacum resin is soluble in ether, chloroform, alcohol,
solutions of caustic alkalies and in chloral hydrate.
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Constituents:
Some of the main resinous constituents belong to the
group of lignans. These are phenolic compounds having a C18
structure formed from C6-C3 units. Guaiaretic acid,which forms
about 10% of guaiacum resin, is a diaryl butane. The resin
contains about 70% α- and β guaiaconic acid and guaiacic acid.
α - guaiaconic acid is the substance which yields the blue
compound guaiac- blue when guaiacum resin is acted upon by
oxidizing agents.
Test for identity:
Dissolve about 0.05 gm of freshly powdered resin in 5 ml
of alcohol and add 1ml. of a solution of ferric chloride in water.
A deep blue color is produced.
Uses
For use as a reagent the resin extracted form wood by
means of chloroform is said to be the most sensitive. An
alcoholic solution is used for the detection of blood stains,
cyanogenetic glycosides, oxidase and peroxidase enzymes. See
guaiacum wood.
3- Mastic ةكتــــــسملا
Mastic is a resin, containing little oil, obtained from
cultivated variety of Pistacia lentiscus Var. chia, family
Anacardiaceae
Collection and preparation:
The base of the shrub is cleared of weed. Flatten and
covered with a special white soil to receive some of the flow.
The stem and larger branches are then wounded by means of
special knife which makes an incision about 2cm long and 3mm
deep. Each plant is tapped repeatedly for about 5 or 6 weeks
receiving in all about 200-300 wounds. A special tool is used
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for the removing the tears which harden on the plant and the flat
plates of mastic which collected on the ground .
Description :
Mastic occurs in yellow or greenish – yellow rounded or
pear-shaped tears about 3 mm in diameter. The tears are brittle
but becomes plastic when chewed. Odor is slightly balsamic, the
taste is mildly terebinthinate.
Constituent:
Mastic is an acid resin and contains triterpenoid acids such
as masticadienonic acid and triterpene alcohols, about 2% of
volatile oil is also present.
Uses:
Used in formerly official aloe and mastic pills to modify
the therapeutic action of the aloe. In dentistry it is employed to
form a varnish, preparation of compound mastic paint. Mastic is
also used as flavoring agent.
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B-Oleoresin
Copaiba,Oleoresina Copaiba
Copaiba is an oleoresin obtained by incision from trunks
of Copaifera Langsdorfii, family Leguminoasae, Copaiba is
sometimes commercially wrongly known as Copaiba balsam .
Description :
Copaiba is a pale yellow, or golden brown, more or less viscous
liquid, more or less transparent with occasional slight greenish
fluorescence. The odor is characteristic and aromatic and taste
somewhat bitter, acrid and persistent.
Copaiba is insoluble in water, and is partially soluble in alcohol,
chloroform, ether, benzene, acetone, carbon disulphide and in
fixed and volatile oils.
Constituent:
Copaiba contains at least 24 sesquiterpene hydrocarbons, resin
acids e.g., capaivic acid, small quantity of a bitter principle and
a fluorescent substance.
Uses
Copaiba is chiefly employed in inflammatory affections of
bladder, urethra and occasionally in chronic bronchitis .
2- Male fern oleoresin. Oleoresina Filicis Malis
Male Fern oleoresin may be prepared by extraction the powder
rhizome, formed bases and apical buds of Dryopteris filix-mass
family poly podiaceae , with ether. The ethereal extract is
evaporated on a water bath until an oleoresinous extract
remains.
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Description :
Male Ferm Oleoresin is a thick dark green liquid, frequently
depositing a granular crystalline sulstance. It has an agreeable
odor and bitter astringent taste. I is insoluble in water, but
soluble in ether and not less than 85% of it is soluble in light
petroleum.
Plate 130
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Constituents :
The active constituent of male Fern are phloroglucinol
derivatives which occur as mon, di, tri, and tetracyclic
compounds. This constituent are acid in nature and termed
filmarone and to which the Taenicide activity of the drug is
due. Filicic, aspidinol, flavaspidic acid, flavaspidinol are also
contained in it. Filmarone occurs as a bright yellowish-brown
powder insoluble in water, soluble, in organic solvent, and
alkali hydroxides and carbonate. It is slowly hydrolysed in the
drug or in solution:
Filmarone → Filicic acid + Aspidinol
∆
↓
Filicin
Filicic acid is therapeutically inert and upon heating , it is
converted to its lactone filicin
Test for identification :
Mix about 0.1 gm of male Fern oleorpsin and 0.2 gm of talc.
Shake vigorously with 10 ml of hot alcohol then filter. Add to 1
ml of the filterate 9 ml of alcohol and 1 drop of ferric chloride
solution a ligh green color is produced which changes to brown.
Uses:
Male Fern oleoresin is used as taenicide.
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C- Oleo-Gum Resin
Asafaetida, Gummiresina Asafaetida تـــيتنحلا
Source :
Asafetida is an oleo-gun-resin obtained by incision from the
living rhizome and root of Ferula feotida, Family Umbelliferae.
The drug is collected in Iran and Afghanistan.
Collection and preparation :
This involves the removal of the stem and cutting of successive
slices from the vertical rootstock. After each slice is removed
oleogumresin exudes and when sufficiently hardened is
collected and packed in tin-lined cases.
Description :
The drug occurs in rounded or flattened tears, from 1.2 to 2.5
cm s in diameter, or as masses of these tears formed by
agglomeration. They are grayish – white to dull yellow. The
freshly exposed surface is yellow and translucent or milk-white
and opaque, gradually passes through a very characteristics
change of color on exposure to the air or light, and finally
reddish brown. The odor is strong and alliaceous persistent and
the taste is bitter alliaceous and acrid.
Constituent
Asafetida consists of volatile oil (10-16%), resin (40-60%), gum
(20-30 %) and impurities. The volatile oil consisting principally
of organic sulfides and pinenes. The resin consisting of
asaresinotannol free and partly combined with ferulic acid.
There is also some free ferulic acid. The drug contains no free
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umbelliferone. On boiling it, however with hydrochloric acid
and filtering into ammonia a blue fluorescence is produced
owing to the formation of umbelliferone. Ferulic acid is closely
related to umbellic acid and umbelliferone
Tests for identity:
1- Place a drop of sulphuric acid on the freshly fractured
surface of a tear, a bright red or reddish-brown color is
produced changing to violet when the acid is washed off
with water
2- Boil 0.5 gm of coarsely powdered drug for few minutes
with 5 ml HCL mixed with 5 ml of water. Filter, cool and
add to the filtrate an equal volume of alcohol and excess
of ammonia, a blue fluorescence is produced.
Uses:
A safetida is now little used in human medicine (as a
carminative, expectorant and antispasmodic) although still
employed incertain food spices
2- Myrrh Gummiresina Myrrha رــــــــــمـلا
Myrrh is an oleo – gum resin obtained from the stems and
branches of Commiphora molmol, family Burseraceae.
Description
Myrrh occurs in tears, rounded or irregular or in masses of tears
varying much in size and shape. The surface is usually covered
with a fine yellowish-brown powder. Beneath this the color is
reddish-brown or reddish-yellow. The fracture is brittle and
uneven.
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Constituents:
Myrrh contains 7-17% of volatile oil, 25-40% of resin, 57-61 %
of gum and 3-4 % of impurities. The volatile oil contains
terpenes, sesquiterpenes, esters, cuminic aldehyde and eugenol.
The gum present in the drug is similar to acacia gum and
contain also an oxidase enzyme.
Test for identity :
Triturate about 0.5 gm of myrrh with 1 gm of sand and shake
with 10 ml of ether. Filter, divide the filtrate into two portions
and evaporate in a porcelain dish. To the film left in one
porcelain dish, add few drops of nitric acid; a purplish-violet
color is produced. Over the film left in the other porcelain dish
pass the vapour of bromine, where a violet color is produced.
Uses :
Myrrh has stimulant and antiseptic properties, it used as a mouth
wash and us uterine stimulant and emmenagogue.
D – Balsams
1- Benzoin ىواجلا
Benzoin is a balsamic resin obtained from the incised stem
of Styrax benzoin known in commerce as Sumatra benzoin
Or Styrax tonkinensis , known in commerce as Siam benzoin
family Styraceae. The trees from which benzoin is obtained do
not contain any special secreting cells or ducts and normally
produce no benzoin, the formation of which is induced by injury
to the tree.
DESCRIPTION
Sumatra benzoin occurs in masses consisting of opaque creamy
white tears embedded in a dull grayish-brown or sometimes
reddish-brown matrix. It is in hard and brittle and the fractured
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surface is dull and uneven. It possesses an agreeable balsamic
odor and slightly acrid taste, when gradually heated it melts and
evolves whitish irritating fumes of benzoic and cinnamic acids,
when a little of the crushed resin is warmed with dilute
sulphuric acid and potassium permanganate, benzaldehyde is
evolved indication the presence of cinnamic acid in the drug.
Siam benzoin occurs in tears or in blocks the tears are of
variable size they are yellowish brown or reddish brown or
reddish brown externally but milky white and opaque internally,
the block form consists of small tears embedded in a somewhat
glassy, reddish-brown, resinous matrix. It has vanillin like odour
and balsamic taste.
CONSTITUENTS
Sumatra benzoin contains free balsamic acid (cinnamic
and benzoic acid) and esters derived form them also present are
triterpenoid acids. The content of total balsamic acids is at least
25% and the amount of cinnamic acid is usually double that of
benzoic acid. Up to 20% of free acids may be present the drug
contains, in addition traces of benzaldehyde, vanillin, phenyl
propyl cinnamate, styrol and styracin.
Siambenzoin consist chiefly of coniferyl benzoate, other
constituents are free benzoic acid, triterpenoid acids and
vanillin.
TESTS FOR IDENTITY:
1- when about 0.5 gm of powdered benzoin is warmed with
10ml of potassium permanganate solution, a faint odor of
benzaldehyde is developed only with Sumatra benzoin but
not with the Siam benzoin.
2- Digest about 0.2gm of the coarsely powdered benzoin
with 5ml of ether for about 5 minutes decant about 1ml of
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the ethereal solution into a porcelain dish containing 2-3
drops of sulphuric acid and mix carefully, a deep purplish
– red color with siam benzoin and deep reddish brown
color in produced with Sumatra benzoin.
Uses:
Benzoin when taken internally acts as an expectorant and
antiseptic, externally it is stimulant and antiseptic.
2- Balsam of Tolu ولوطلا مسلب
Balsamum tolutanum
Balsam of tolu is balsam obtained by making incisions in trunk
of Myroxylon balsamum, Family Leguminosae.
Description:
Balsam of Tolu when freshly imported is a soft yellowish -
brown semi – solid, resinous mass which takes the form of the
vessel in which it is kept, on keeping it gradually hardens to
brownish and especially in cold weather brittle and easily
powdered, readily soften when warmed, it has an agreeable
fragrant odor which is not powerful and an acidulous balsamic
taste and adhere to the teeth when chewed. It is easily soluble in
alcohol, acetone, and chloroform.
Constituent:
Tolu balsam contains about 7.5 % of an oily liquid consisting
of benzyl benzoate with little benzyl cinnamate, traces of
vanillin, free aromatic acids, principally cinnamic (12-15%)
and benzoic acid (8%).
The resin forming about 80% of the drug, yields by
saponification the alcohol toluresinotannol, cinnamic acid
and little benzoic acids.
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Test for identity
1- A solution of balsam tolu im alcohol is acid to litmus
paper
2- To an alcoholic solution of the balsam (5%) add a few
drops of ferric chloride a green color produced
3- Boil 1gm of balsam of tolu with 5ml of water filter add to
the filtrate 3ml of potassium permanganate and warm the
odor of benzaldehyde is developed.
Use:
Tolu balsam in used chiefly as a pleasant ingredient in
cough mixtures it possesses antiseptic properties due to cinnanic
and benzoic contained in it .
3-Balsam of Peru, Balsamum peruvianum
وريب مسلب
Balsam of Peru is a balsam exuded from the trunk of
Myroxylon pereirae, family Leguminosae, after the trunk has
been beaten and scorched.
DESCRIPTION
Balsam of peru is a rather viscid oily liquid, free from
stickiness and stringiness.
It appears black in bulk, but in thin layers it is dark reddish –
brown and transparent. It has a fragrant balsamic odour,
somewhat vanilla – like odor and acrid slightly bitter taste.
The drug is almost insoluble in water. It is soluble in equal
volume of alcohol. The specific gravity, 1.1470-1.170 is a
good indication of purity.
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Constituents:
Balsam of peru consists mainly of an oily fluid portion
mixed with dark resin. The fluid potion (cinnamein) constitutes
from 56-90% of the drug and consists of benzylbenzozte and
benzyl cinnamate. It also contains about 28% of resin consisting
of peruresinotannolcombined with cinnamic and benzoic acids,
small quantities of vanillin and free cinnamic acid.
Test For Identity
Shake about 0.5 gm of balsam Peru with 10 ml of water
,the aqueous solution is acid to litmus.
Uses:
Balsam of Peru is used internally as an antiseptic and
expectorant; applied externally it acts as an antiseptic and
parasiticide, especially for scabies.
Dried latex
Latex is an emulsion or suspension, the continuous phase
of which is an aqueous solution of mineral salts, proteins sugars
tannins, alkaloids, etc., and the suspended particles are oil-
droplets, resin, gum, proteins, starch, caoutchouc. This turbid
fluid is often white in color, as in opium (Papaver somniferum),
but may be yellow as in Argemone mexicana or red as in the
rehizome of Sanguinaria Canadensis. Latex occurs in the plant
in special structures named laticiferous cells, tubes or vessels,
from which it is obtained by incision into the plant.
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Opium نوـــــــــــــــــــــــــــــــــــيفلأا
Opium is the our dried latex obtained by incision from the
fully grown but unripe capsule of Papaver somniferum, family
Papaveraceae.
Collection and preparation
While the capsules are still green or just showing a tint of
yellow, incision are made in the walls, so as not to penetrate
into the loculas, which would result in loss of opium and also
prevent the seeds from ripening . Precaution must be taken to
chose the time for making the incisions so that neither rain,
wined nor dew is likely to spoil the exudation. The incision cuts
acros the laticiferous vessels and, since these vessels ramify and
anastomose throughout the phloem tissues of the capsule wall,
the latex from a large area of the capsule exudes in small drops
along the edges of the incisions and partially dries in air. The
incisions are usually made in the afternoon and the exuded latex
in scraped off with a knife or special instrument early in the
following morning. The collected exudate is mixed and dried
and packed.
Description
Opium occurr in more or less rounded or cubical pieces or
some what flattened or brick – shaped masses usually about 8-
10cm in diameter, varying in weight but commonly weighing
between 250-1000gm, sometimes wrapped in tissue paper,
cellophane or covered with poppy leaves; externally dark brown
to chocolate brown; more or less elastic when fresh, becoming
hard and tough, or occasionally brittle on keeping, internally
dark brown, coarsely granular or nearly smooth. Opium has
strong charaeteristic narcotic odour and characteristic very bitter
taste.
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Plate 131
Constituents
Opium contains about 30 different alkaloids, belonging to
different chemical groups which occur in combination with
MECONIC acid, of which about 5% is present, and with
sulphuric acid. Other constituents are small amount of mucilage,
sugars, wax caoutchouc and salts of calcium and magnesium.
The most important alkaloids are morphine (10-20), codeine
(methyl morphine 0.3-0.4%), narcotine (2-8%), thebaine ( 0.2-
0.5%) narceine, and the remaining alkaloids are present in very
small quantities constituting together rather more than 1% of the
drug.
Test For Identity
Warm about 20-30mg of powdered opium in 2-3 ml of
water for few minates and then filter. On adding a few drops of
5% ferric chloride solution to the filterate, a purplish red color is
produced and the color is not destroyed by the addition of dilute
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hydrochloric acid or 5% mercuric chloride solution (Test For
Meconic Acid)
Uses:
Opium is unexcelled as a hypnotic and sedative and
frequently administered to relieve pain and calm excitement. It
is also used as an astringent in diarrhoea and dysentry and
sedative in certain forms of cough. Its action is due to the
morphine content. All the important alkaloids have narcotic
action which decreases in the following order; morphine,
papaverine, codeine, narcotine, the baine.
2- ALOE ربـــــــ ــــصلا
Aloes is the solid residue obtained by evaporating the
juice which drains from the cut leaves of Aloe ferox and its
hybrids known in commerce as Cape aloes or of Aloe vera,
known in commerce as Curacao Aloes, or of Aloe Perryi,
known in commerce as socotrine or Zanzibar Aloes, family
Liliaceae.
Preparation Of Cape Aloes
The leaves are cut transversely near the base and about
200 of them are arranged around a shallow hole in the ground
which is lined with a piece of canvas or a goatskin. The leaves
are arranged as that the cut ends overlap and drain freely into
the canvas. After about 6 hours all the juice has been collected
and it is transferred to a drum in which it is boiled for about 4
hours on an open fire, the product is poured whilst hot into tins,
where it solidifies.
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Plate 132
DESCRIPTION
Cape aloe occurs in dark-brown or greenish-brown glassy
masses. Thin fragments have a deep olive color and are semitrans
parent. The powder is greenish-yellow, and has a very
characteristic odour while the taste is very bitter and nauseous.
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Constituents:
The principle constituent of all varaties of aloes is a pale
yellow crystalline substance known as barbaloin which is a
C- glycoside. In Curacao aloes barbaloin is accompanied by
isobarbalain which is crystalline and isomeric with baraloin.
Other constituents of aloes are resin and aloe-emodin,
which is ahydrolytic decomposition product of barbaloin.
Test For Identity
1- Borax test: Make a 1% solution of aloes in boiling water,
cool and then filter. To 10ml of the filtrate add 0.25 gm of
borax and dissolve by heat; pour some of the dark fluid
into water where a green fluorescence is produced. All
kinds of aloes respond to this test.
2- Bromine test: to some clear solution of aloes prepared
above, add an equal volume of saturated solution of
bromine. A yellow precipitate of tetrabromoaloin is
formed: All kinds of aloes respond to this test
Uses:
All varities of aloes have more or less powerful purgative
action. Aloe is one of the most voluble purgatives in certain
forms of constipation, as it improves the digestion and does not
lose in activity by repetition. Externally, aloe is used in cream
forms for diabetic ulcers and to promote hair growth.
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Extracts
Under this heading are grouped to gether drugs prepared
by evaporating aqueous decotion of part of certain plants or
animals.
Gelatin Gelatimum نيتلاجلا
Gelatin is a protein derivative often classed as
scleroprotein or albuminoid, obtained by evaporating an
aqueous extracts made from skim tendons and bones derived
from various domestic animals, such as ox (Bos Taurus), the
sheep ( Ovis aries), family Bovidae.
Preparation:
Raw material consisting of the skin and tendon is first
subjected to a preliminary treatment known as liming, in which
the material being soaked for about 20 days in dilute milk of
lime. This process dissolves the fleshy matter, remove
chondroproteins of the connective tissues and saponifies fats.
The hides are then thoroughly washed in running water.
Bones are usually ground and defatted by treatment with
benzene, after deffatting the mineral matter is removed by
treatment with hydrochloric acid. The treated materials from
skins, tendons or bones is now heated with water in open pans
with perforated false bottoms or sometimes under reduced
pressure. The clear fluid is run off and is evaporated under
reduced pressure until the gelatin content is about 45%. It is
then run into shallow metal trays and allowed to set to a jelly.
The jelly is removed and placed in trays with a wire
netting bottom; this trays are passed through a series of drying
rooms at temperatures, increasing by about 10 C o each time,
from 30 C o to 60 C o ; this drying process takes about a month.
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Sometimes bleaching by sulphur dioxide is used to produce a
ligh-colored product.
Description:
Gelatin occurs in thin sheets or in shreds, or powder which
may be nearly colorless. It is hard and brittle; when broken it at
first bends and then breakes suddenly with a short fracture .
In cold water it swells and when heated dissolves, it is
soluble in acetic acid and glycerol, but not in alcohol and ether.
A 2 % hot a queous solution should gelatinse on cooling.
Constituents:
Gelatin consists of the protein glutin and, when it is heated
with soda lime,ammonia is evolved, showing the presence of
nitrogen of which it contains about 18%.
Test for identity:
An aqueous solution of gelatin gives a precipitate with
solution of chromium trioxide, tannic acid, trinitrophenol and
lead subacetate, h Millons reagent it gives a white precipitate
which becomes red on boiling .
Uses
Gelatin has been used a nutrient. It is also used as a basis
for glycerin suppositories, for the preparation of pastilles and
for the preparation of nutrient media for the growth of bacteria.
2- Agar-Agar, Japanese Isinglass راـــــجّا راـــــجّا
-
Agar
Agar is the bleached and dried product obtained by
concentrating a decoction made from various species of algae
belonging to the class Rhodophyceae. Agar from Japan is made
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chiefly from species of Gelidium, especially G. elegans and G.
amansil, family Gelidiaceae.
Preparation:
In Japan the seaweeds are collected by removing them
from the ocean floor. They are then spread upon beach to dry.
The dried seaweeds are beaten and shaken to remove sheels,
sand etc. لإ weed is washed water, bleached by exposure to the
sun and then boiled in open boilers for 5-6 hours with about 50
times its weight of very faintly acidulated water. The liquor is
strained through cloth and transferred to wooden troughs (100 x
40 x 8 cm ) where it is allowed to cool in the open air and the
liquid congeals. The jelly is cut into pieces about 5 x 8 x 40 cm ,
using knifes guided by a ruler. These rectangular pieces of jelly
is then forced through a netting and the narrow strips thus
formed are spread out to dry and bleaching in the air and
sunshine.
Description:
Japanese agar occurs in grayish white, transulucent strips
about 60 cm by 0.5 – 1 cm and 0.1 mm thick. The surface
crinkled and various species of diatoms are found embedded in
it. Agar is tough and difficult break, it has a slight odor of
marine algae and a faintly salty mucilaginous taste. It swells in
cold water and 0.75 – 1 % boiled with water forms a colloid
fluid, which sets to a firm jelly on/cooling:
Constituents:
Agar is composed chiefly of a calcium salt of a sulphuric
acid ester of a carbohydrate complex. When hydrolysed by
boiling with dilute hydrochloric acid it yields galactose and
sulphuric acid. Agar contains a small traces of proteins .
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Test for identity:
1- Add few drops of N/50 iodine solution to a small a mound
of powdered agar, placed in a white porcelain dish, a deep
crimson color is produced (distinction from gum cacia and
Tragacanth).
2- Boil about 1 gm of agar with a mixture of 10 ml of water
and 5 ml of dilute hydrochloric acid, for 10 minutes, set
aside for about 15 minutes or centrifuge the solution.
Decant the liquid and mount some of the deposit in water.
Examine under the microscope for spong specules.To bout
4 ml of the decanted solution add 1 ml of barium chloride
solution a white precipitate is produced indicating the
presence of sulphate radicle.
3- Alkalinise about 2 ml of the above decanted solution then
add 4 ml of Fehlings solution and heat in a boiling water
bath . Reduction of the reagent is produced by the sugar
resulted from the hydrolysis of agar.
Uses:
Agar-agar is largely used for the preparation of
bacteriological culture media. Agar passes through the intestinal
canal unchanged, but absorbs water during its passage and thus
promotes peristalsis, for which purpose it is frequently used for
treatment of constipation .
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Gums
غومصلا
Gums are amorphous, translucent solids, insoluble alcohol
and most organic solvents; but soluble in water to yield viscous,
adhesive solutions, or are swollen by the absorption of water
into a jelly-like mass. They consists of calcium potassium and
magnesium salts of complex substances known as polyuronides,
and can be hydrolysides by prolonged boiling with dilute acids
when they yield mixtures of sugars and organic acids. The
sugars so formed are monosaccharides, usually pentoses such as
arabinose, xylose or hexoses such as galactose. The acids
liberated by hydrolysis are uronic acids i.e., acids derived from
monosaccharides by oxidation of the primary alcoholic group
which they contain as glucuronic and galocturonic acid. Pectins
and hemicelluloses also yield on hydrolysis, uronic acids and
sugars, thus showing a relation-ship with gums. Gums are
produced by the conversion of the cell-walls of the tissue into
gums, probably by means of enzymes.
Gums are abnormal products , resulting from pathological
conditions brought about either by injury or by unfavourable
conditions of growth and are usually formed by changes in the
existing cell-walls.
Mucillages are similar in constitution to gums, but are
normal products of cell activity, being secreted in the cell and
laid down like hemicelluloses.
Artificial gum (desxtrin) is produced from starch, differs
originally from gums in being entirely converted into dextrose
(glucose) by dilute mineral acids, it is strongly destroy rotatory
while natural gums being slightly laevortatory.
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1-Acacia Gum, Gum Arabic ىبرعلا غمصلا
Acaciae Gummi
Gum Arabic is the dried Gummy exudation from the stems
and branches of Acacia Senegal or of some other species of
Acacia, family Leguminosae.
Description:
Kordofan gum , which is the best variety occur in rounded or
ovoid tears, about 0.5 to 4 cm in diameter . they are often quite
white , but sometimes show a yellowish tinge, and are opaque
from the presence in the outer part of the tears of numerous
small fissures. It is brittle in nature and easily break up into
smale transparent angular fragments with glistening vitreous
surface. The gum is almost odorless and has a bland,
mucilaginous taste.
Inferior grades of gum Arabic have yellow or reddish or
brownish – red color as they contain traces of tannin
Gum Arabic in insoluble in alcohol, but dissolves freely in
water , forming translucent, viscid liquid.
Powdered gum Arabic is white to yellowish-white in color,
showing under the microscop angular particles, slight traces or
no starch granules, occasional particles of vegetable tissues
Constituents:
Gum Arabic consists almost entirely of glycosidal acid
named Arabic acid, combined with potassium, magnesium
and calcium. By hydrolysis Arabic acid yields 1 molecule of
l-rhamnose, 2 molecules of D – galactose and 3 molecules of
l – arabinose and an aldobionic acid. It also contains diastase
and an oxidase enzyme
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Test for identity:
1- Dissolve about 0.25 gm of the coarsely powdered drug in
5 ml of distilled water by shaking in the cold. Add 0.5 ml
of hydrogen peroxide and 0.5 ml of benzidine solution,
shake and allow to stand for few minutes; a deep blue
color or greenish blue color is formed due to the prescence
of oxidase enzyme
Uses :
Gum Arabic is used medicinally as a demulcent and as a
suspending and emulsifying agent for oils.
2- Tragacanth Gum ءاريثكلا غمص
Gummi Tragacanthae
Tragacanth gum is the dried gummy exudation from stem
of Astragalus gummifer, family Leguminosae, and other Asiatic
species of Astragalus.
The gum exudes immedialty after the injury and therefore
being performed in the plant while accasia is slowly produced
after injury. A section of a tragacanth stem shows that the cell
walls of the pith and medullary rays are gradually transformed
into gum, the change being termed gummosis.
Description:
Persian tragacanth occurs in thin, flattened, curved, ribbon
– shaped flakes of a translucent , horny appearance and nearly
colorless or faintly yellowish. The flakes are 3 cm long, 1 cm
wide and about 2 mm. thick , and are marked with numerous
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concentric longitudinal and transverse ridges, giving the
impression that the gum has been exuded in successive portions.
The flakes break with short fracture, they are odorless and
almost tasteless. Soaked in cold water they swell considerably
forming a gelatinous mass, but only 8 to 10 % dissolves.
Constituents
Tragacanth can be separated into two parts on the basis of
its behavior when added to water; the portion soluble in water
is named tragacanthin and the insoluble portion is named
basorin. Tragacanth contains also traces of starch, cellulose and
nitrogenous substances. No oxidase enzyme is present.
Test for identity:
Place a little powdered gum traganth on a porcelain tile,
add few drops of N/50 iodine solution and rub to form a smoth
paste. It acquires an olive green color.
Uses:
Tragacanth is used in pharmacy as a suspending agent for
insoluble powders or as a binding agent in pills and tablets.
Very large quantities are used as a thickening agents in calico
printing and also in the manufacture of cosmetics
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