INTR

ODUCTION

TO

PHARMACOGNOSY

DEFINITION :

Pharmacy is the science of drug

making / deals with their procurement

(bring about), testing, storage and

conversion into suitable forms

( tablets, capsules, emulsions etc)

DRUG :

Any substance used in the

treatment of disease or diagnosis is

known as drug . Diagnosis is the

determination of nature of disease.

CRUDE DRUG

It is the simple drug ,crude drugs are

plant, animal and their parts which after

collection are subjected only to drying or

making them into transverse or

longitudinal pieces or peeling (stripping

off skin or bark).They exist in natural

forms.

SOUCES OF DRUG

Drugs used in medicine may be organic and inorganic

in nature. Organic drugs are essentially of 2 types .

1. Purely synthetic : The product of man ‘s

creation of new chemical entities ( structures) non –

existent before the era of synthetic

chemistry. 2.Drugs of

biological origin : Produced in the living cell, biogenic

drugs (crude drugs)

PHARMACOGNOSY

Pharmacognosy is the science of drugs of

biological origin ( plant, animal, mineral)

or The word

pharmacognosy was coined in 1815 by a German

Scientist SEYDLER has been derived from two

Greek words , Pharmacon ---- ‘ a drug, gignosco

– ‘ acquire the knowledge of

Pharmacognosy is the subject of crude

drugs obtained from the plants

(vegetable), animal and mineral origin.

Or It can also defined as the objective

study of crude drugs of the natural

sources processed scientifically.

The pharmacognosy is broadly defined as

the scientific and systematic study of the

structural, physical, chemical and sensory

characters of crude drugs of vegetable,

animal and mineral origin along with their

history, method of cultivation, collection

and preparation for the market.

Recently it includes:

1- Modern isolation techniques.

2- Pharmacological testing procedures to prepare purified substances.

3- Cultivation and propagation by tissue culture

SCOPE OF PHARMACOGNOSY

• Pharmacognosy has broad scope in the field of pharmacy such as :

• 1. ISOLATION OR ANALYSIS OF PHYTOCHEMICAL :

• Eg ; Strong acting substances such as glycosides from

digitalis leaves,

• Alkaloids from the plants of Belladonna, Hyocyamus,

Rauwlofia

• Morphine and other alkaloids from the plant opium were

isolated and clinical uses studied

2. STRUCTURE ACTIVITY RELATIONSHIP :

Eg : Tubocurarine and Toxiferine from curare

plant have muscle relaxant properties because

of quaternary ammonium groups.

The hypotensive and tranquillizing actions of

reserpine are due to the trimethoxy benzoic

acid

3. DRUGS OBTAIN:ED BY PARTIAL SYNTHESIS OF NATURAL PRODUCTS:

Eg : Preparation of Steroid hormones from diosgenin by acetolysis

and oxidation and further preparation of cortisone by microbial

reactions.

4. NATURAL PRODUCTS AS MODELS FOR SYNTHESIS OF NEW DRUGS :

Eg: Morphine is the model of a large group of potent drugs .

Cocaine for local anaesthetics

Atropine for certain spasmolytics

• 5. DRUGS OF DIRECT THERAPEUTIC USES :

• Among the natural constituents which even now cannot be

replaced are important group of antibiotics, steroids, ergot

alkaloids, vincristine etc

• 6. BIOSYNTHETIC PATHWAYS INVESTIGATION :

• Biosynthetic pathways are of primary and secondary

metabolites.

• Some of the important pathways are Clavin ‘s cycle of

photosynthesis,

• Shikimic acid pathway of aromatic compounds

• Acetate hypothesis for antharacene glycosides

• Isoprenoid hypothesis for terpens

• 7.CULTIVATION AND COLLECTION OF MEDICINAL

PLANTS :

• clove, cinchona , cinnamon, senna, opium, etc

• 8. PREPARATION OF HERBAL FORMULATIONS :

• churnas, asvas, aristas, leha, etc

• 9. DEVELOPMENT OF TISSUE CULTURED PLANTS

Physical parameters

1.Mosture content

2.Ash values

3.Swelling factor

4.Extractive values

5.Melting point

6.Solubility

7.Optical rotation

8.Viscosity

ASH VALUES

The residue remaining after incineration is

the ash content of the drug.( inorganic

salts of carbonates, phosphates, silicates

of sodium, potassium, calcium and

magnesium) is known as ash content.

Ash value is a criterion to judge the identity

OR purity of the crude drug

TYPES OF ASH VALUES

1.Total ash value

2.Acid insoluble ash value

3.Sulphated ash value

4. Water soluble ash value

Total ash value:

Useful for detecting low grade products

Useful for detecting exhausted products

Useful for detecting excess of sandy

Useful for detecting earthy matter with

drug

DETERMINATION

1.Weigh accurately about 3gms of the powdered drug in a

tared silica crucible

2.Incinerate the powdered drug by gradually increasing the

heat until free from carbon and cool. Keep it in

desiccators

3. Weigh the ash and calculate the % of the total ash with

reference to the air dried sample

Acid insoluble ash value :

1. Used for the determination of earthy matter present on

roots, rhizomes, and also on the leaves

2. Crude drugs contain calcium oxalate crystals the amount

may varies depending on the environmental conditions

DETERMINATION

1. Boil the total ash obtained as above for 5 minutes with

25ml of dilute HCL

2.Filter and collect the insoluble matter on the ashless filter

paper , wash the filter paper with hot water, ignite in

tared crucible, cool and kept in desiccators

3.Weigh the residue and calculate the acid insoluble ash of

the drug

Sulphated ash value :

Used for the detection of low grade products

Water soluble ash value :

Used to detect either material exhausted by water or not

( Tea leaves, Ginger rhizomes)

SWELLING FACTOR

Significances :

Useful in the evaluation of crude drugs containing

mucilage

Useful for the detection of purity of the crude drug

DETERMINATION

1. Transfer 1 gm of the seeds to a 25ml

stoppered cylinder

2. Fill up to the 20ml mark on the cylinder

with water. Agitate gently and occasionally

during 24 hours and allowed to stand

3.Measure the volume occupied by the

swollen seeds

EXTRACTIVE VALUES

Significances :

1.Useful for the evaluation especially when the constituents of the drugs can not be readily estimated by any other means

2.It also helps to indicate the nature of chemical constituents present in the drug

3. Also helps in the identification of adulterants

TYPES

1.Water soluble extractive values

2.Alcohal soluble extractive values

3.Ether soluble extractive values

1.Water soluble extractive value is applied

for the drugs which contain water soluble

constituents such as tannins, sugars, plant

acids and mucilage.

2.Alcohol soluble extractive value is applied

for the drugs which contain alcohol soluble

constituents such as tannins, resins and

alkaloids

Official method for the assay of myrrh &

asafoetida

3.Ether soluble extractive value is

applied for the extraction of volatile

oils, fixed oils and resins.

1.Volatile ether soluble extractive

value

2.Non volatile ether soluble extractive

value

DETERMINATION

Water soluble extractive value:

1. Macerate about 5gm of the accurately weighed

coarse powder with 100ml of chloroform water in a

100ml volumetric flask for 24 hours .

2. Shake frequently for first 6 hours

3. Filter rapidly through filter paper and evaporate

25ml of water extract to dryness in a tared flat-

bottomed shallow dish.

4. Dry the residue at 105 and weigh. Keep it in a

desiccators

5. Dry the extract to constant weight ,finally , calculate

the % W/W of Water soluble extractive value with

reference to the air dried drug.

• Alcohol soluble extractive values

• Macerate about 5gm of the accurately weighed coarse

powder with 100ml of 90% alcohol in a 100ml stoppered

flask for 24 hours .

• Shake frequently for first 6 hours

• Filter rapidly through filter paper and collect the filtrate

evaporate 25ml of alcohol extract to dryness in a tared flat-

bottomed shallow dish.

• Dry the residue at 105 and weigh. Keep it in a

desiccators

• Dry the extract to constant weight ,finally , calculate

the % w/w of alcohol soluble extractive value with

reference to the air dried drug.

SIGNIFICANCE:

1.The method is generally used when standardization is not

done satisfactory by chemical or physical methods

2.When the quantity of the drug /sample are very less then

the drugs are evaluated by biological methods

These methods are performed on living animals,

isolating living organ and tissue, animal preparation, and

micro-organism

( Bioassay)

Following method is used as

1.Anti inflammatory activity

2.Analgesic activity

3.Antipyretic activity

4.Anti ulcer activity

5.Antidiabetic activity

6.Anthelmintic activity on earth worms

7.Cardiac activity- on frog and pigeon

8.Microbiological methods- living bacteria, yeast, molds are

used for the assaying vitamins and to determine the

activity of antibiotic drugs