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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

197

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.

198

A- RESINS

1- Colophony القلفونية 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.

200

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 المســــــتكة 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 الحنتيـــت 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 الـمــــــــــر

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 الجاوى

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 بلسم الطولو

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.

210

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 بلسم بيرو

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 فيـــــــــــــــــــــــــــــــــــون� اOpium 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.

213

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

214

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 ـــــــبر الصــــ 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.

215

Plate 132

DESCRIPTION

Cape aloe occurs in dark-brown or greenish-brown glassy

masses. Thin fragments have a deep olive color and are semi-

trans parent. The powder is greenish-yellow, and has a very

characteristic odour while the taste is very bitter and nauseous.

216

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.

217

Extracts

Under this heading are grouped to gether drugs prepared

by evaporating aqueous decotion of part of certain plants or

animals.

Gelatin Gelatimum الج"تين 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 Co each time,

from 30 Co to 60 C

o; this drying process takes about a month.

218

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 اّجـــــار اّجـــــار-

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. � 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

الصموغ

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 الصمغ العربى 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 صمغ الكثيراء

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