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1. PHARMACOGNOSY.
• Pharmacognosy is “an applied science that deals with the biological, biochemical
and economic features of natural crude drugs and their active constituents” from
plant and animal kingdoms and their natural derivatives.
CRUDE DRUGS.
• They are vegetable or animal drugs that consist of natural substances that have undergone
only the processes of collection and drying.
• The term natural substances refers to those substances found in nature, SUCH AS
• Whole plants or organs of plants, e.g. leaves, flowers, seeds, and barks,
• OR vegetable , extracts and secretions.
• any product that has not been advanced in value or improved in condition by grinding,
chipping, crushing, distilling, evaporating, extracting, artificial mixing with other
substance.
Sources of Crude Drugs:
• Plant sources, e.g. Senna, Digitalis, Datura, Cascara, Cinchona, Clove, Opium, etc.
• Animal sources, e.g. cochineal, cantharidin, honey, cod liver oil, musk, thyroxin, etc.
• Marine sources, e.g. sponges, red algae, agar, etc.
• Mineral sources, e.g. talc, kaolin, kieselguhr, etc.
Uses of Natural products:
1. As drugs for the treatment of a wide range of diseases, e.g. morphine, atropine, digoxin,
hormones, antibiotics, etc..
2. As pharm. aids in pharm. industry, e.g. suspending & emulsifying agents, suppository
bases, binders, excipients, sweetening & colouring agents, etc..
3. In cosmetics as flavouring & colouring agents, etc.
4. In culture media for the propagation of M.O. in microbiology laboratories &
biotechnology.
5. General uses e.g. in food industries: as dusting powders, as indicators and in perfumery.

2. Classification of Medicinal Plants:
- Alphabetical:
Either Latin or Vernacular عامي names may be used.
Although they are simple and suitable for quick references, It gives no indication of
interrelationships between drugs e.g. Pharmacopoeias.
- Taxonomic:
Based on botanical classification, drugs are arranged according to the plants from which they are
obtained, into:
Classes, orders, families, genera and species.
- Pharmacological or therapeutic:
This involves the grouping of drugs according to the pharmacological action of their most
important constituents or their therapeutic uses, e.g cardiotonic drugs.
References Containing Monographs on Medicinal Plants:
• British Herbal Pharmacopoeia, 1996.
• The British Herbal Compendium Vol. 1& 2, 1993.
• The United States Herbal Pharmacopoeia.
• German Commission Monographs.
• The Chinese Herbal Pharmacopoeia.
• Monograph
The descriptive material pertaining to any of the drugs in the Pharmacopoeia is known as
the monograph.
• In the monograph of a crude drug, the following information are generally covered:
• The descriptive material pertaining to any of the drugs in the Pharmacopoeia is known as
the monograph.
• In the monograph of a crude drug, the following information are generally covered:

3. Origin of Crude Drugs:
The natural or biological origin:
Botanical origin is used for a plant and
Zoological origin is used for of animal.
• Benefit of Botanical Origin of the Crude Drugs
• Knowledge of the biological origin enables one to indicate the proper right material and
precise the source .
• E.g. one year the drug is active, even poisonous and in other cases it is inactive, e.g.
Strophanthus seeds
• Benefit of Botanical Origin of the Crude Drugs
Geographical source:
• - Cinnamoum zeylanicum ( growing in Ceylon)
• - Hydrastis Canadensis (growing in Canada)
• - Tamarindus indica (growing in India)
• - Uriginia maritima (near the coast)
Pharmacological activity:
• - Papaver sominferum (inducing sleep)
• - Lytta vesicatoriam (causing blistering)
• - Strychnos nux-vomica (causing vomiting)
• - Ipomoea purge (purgative action)

4. Production of Crude drugs.
The preparation of each drug for the market depends on its morphological nature, constituents,
geographical source and other factors.
Collection of Crude Drugs:
1. Effect of Time of the Year (Seasonal var.):
It has been found that active constituents in plants vary in amount and nature throughout the
year.
- Rhubarb is collected in summer (anthranol in wintrer→anthraquinones in summer).
2. Time of the Day
- Digitalis is collected in the afternoon.
- Solanaceous leaves collected in the morning.
- Salix collected at night.
3. Stage of maturity and age:
- Clove: collected in bud form.
- Santonica fl & tea leaves: in as unexpanded flower buds.
- Solanaceous leaves: at flowering stage.
- Pyrethrum flower: in fully expanded.
4. General factors:
- Flowers are collected in dry weather.
- Leaves are collected when plant is flowering.
- Fruits and seeds when fully mature but unripe.
- Underground organs when aerial parts die down.
- Barks in spring (when they are easily separated).
- Unorganized drugs in dry weather (not rainy).

5. Drying of Crude Drugs.
Reasons of Drying:
- To decrease size and weight (facilitate packing, transport and storage).
- Facilitate powdering.
- Prevent enzyme action, microbial growth and
degradation of active constituents.
Enzyme action
Desirable: e.g. Vanilla pods, required slow drying.
Undesirable: e.g. Digitalis leaves, required fast drying
Methods of drying:
1. Drying in open air: in sun and under cover sheds at night or during wet weather, e.g.
clove, cinnamon,...
2. Artificial oven drying.
(Oven-drying is more rapid than air- drying, controlled temp. and more suitable for use in the
wet weather countries. Leaves, herbs & flowers: 20-40oC, barks & roots: 40-65oC.
3. Vacuum drying:
Eg in oven, rapid and at low temp.
4. Lyophilization used for biological fluids, enzymes, proteins and royal jelly.
Storage of Crude Drugs:
During storage, Drugs are affected by light, moisture, temp., air oxygen (physicochemical) and
by fungi, bacteria, worms, insects and mites (biological)
• Long storage is not recommended, due to deterioration.
• Therefore, drugs should be stored in sealed containers in cool dark places.
Evaluation of Crude Drugs .
Means to identify and to determine quality, safety and purity. It has to be certain of identity of
the collected plant from proper source by matching to authentic plant sample
Preparation by proper cleaning, drying and garbling.

6. Proper preservation of cleaned, dried, pure drug against contamination.
Evaluation of drugs involves the following methods:
1. Organoleptic 2. Microscopic 3. Chemical 4. Physical
I- ORGANOLEPTIC EVALUATION
Organoleptic refers to evaluation by means of the organs of sense which includes:
- The macroscopic appearance of the drug,
- Its odour and taste and the feel of the drug to the touch.
Description of the macroscopic characteristics of a drug include:
1. Shape and size.
2. Colour and external markings
3. Fracture and internal colour.
4. Odour and taste.
II-MICROSCOPIC EVALUATION
The microscope is essential in the identification of powdered drug and in the detection of
the adulterants in powdered plant or animal drugs.
Microscopical description of the drug in sectional view and powdered form is listed in official
monograph .
■ Histology refers to the character & arrangement of the tissues in a drug.
■ Some drugs have no cellular structure (gums, resin).
■ Some are composed of microscopic units, such as diatoms (kieselguhr) or hairs (Lupulin,
kamala).
■ Histological studies on very thin transverse (TS) or longitudinal (LS) sections properly
mounted in suitable stains, re In the powdered drugs the cells are mostly broken, except
those with lignified walls, but the cell contents (starch, calcium oxalate, aleurone grains
…etc) are scattered in the powder and become very evident in the mounted specimen.

7. ■ Microscope can be used for a quantitative microanalysis of admixed or adulterated
powders.
■ This study is done by counting a specific histological feature (stomatal index, palisade
ratio) in a measured quantity of the unknown powder and comparing the count with that
obtained for the same feature in a known standard sample.
■ agents or mounting media. In the powdered drugs the cells are mostly broken, except
those with lignified walls, but the cell contents (starch, calcium oxalate, aleurone grains
…etc) are scattered in the powder and become very evident in the mounted specimen.
■ Microscope can be used for a quantitative microanalysis of admixed or adulterated
powders.
■ This study is done by counting a specific histological feature (stomatal index, palisade
ratio) in a measured quantity of the unknown powder and comparing the count with that
obtained for the same feature in a known standard sample.
III-CHEMICAL EVALUATION:
 Chemical tests are employed to identify crude plant drugs.
E.g. characteristic red colour developed in Cascara on addition of NH3 test solution.
To ascertain the purity of certain drugs , E.g. to detect the presence of inorg. iodine in
thyroid tablets by adding a starch test solution.
 Chemical assays are dependent on the pharm. extractive processes with subsequent
purification of the main constituent.
In many drugs the chemical assays represents the only method of determining the official
potency
IV-PHYSICAL EVALUATION
 Typical physical constants is very rare.
 The specific gravity is used with nutgalls, where the galls that will not sink in H2O are
considered to be of inferior quality,
 In jalap and clove, the specific gravity should be higher than that of water.
 The elasticity of certain fibers, such as cotton, is a physical constant of importance.

8.  Alkaloids aconitine (light blue), berberine (yellow), emetine (orange).
 Alkaloid quinine has blue fluroscence in acid solution in UV or even in daylight.
 The use of physical constants on active constituents.:
 Solubility, specific gravity, optical rotation, melting point… etc
The response of some drugs in powdered form or in their smooth section surface to the UV ,
e.g. in detecting of adulteration of genuine of rhubarb from rhapontic rhubarb (blue
fluroscence).
Extraction:
is the separation of medicinally active portion of plants or animal tissues through the use of
selective solvent and suitable methods extraction. Extraction may be defined as the treatment of
the plant or animal tissues with solvent, whereby the medicinally active constituents are dissolved,
and most of the inert matter remains undissolved.
The solvent used for extraction is known as Menstruum and the inert insoluble material that
remains after extraction is called Marc .
The principal methods of extraction are:
1- Maceration
2- Percolation
3- Infusion
4- Decoction
5- Digestion
6- Continuous hot extraction technique
(Soxhlet extraction process).
7- Liquid-liquid extraction
8- Solvent-solvent ppt.
9- Distillation.
The various process used for extraction are

9. 1. Maceration
In this process, the whole or coarsely powdered crude drug is
placed in a stoppered container with the solvent and allowed to stand at room temperature for
a period of at least 3 days with frequent agitation until the soluble matter has dissolved. The
mixture then is strained, the marc (the damp solid material) is pressed, and the combined
liquids are clarified by filtration or decantation after standing.
2. Infusion .
Fresh infusions are prepared by macerating the crude drug for a short period of time with
cold or boiling water. These are dilute solutions of the readily soluble constituents of
crude drugs.
3. Digestion
This is a form of maceration in which gentle heat is used during
the process of extraction. It is used when moderately elevated temperature is not
objectionable. The solvent efficiency of the menstruum is thereby increased.
4. Decoction
In this process, the crude drug is boiled in a specified volume of water for a defined time;
it is then cooled and strained or filtered. This procedure is suitable for extracting water-soluble,
heatstable constituents. The starting ratio of crude drug to water is fixed, e.g. 1:4
or 1:16; the volume is then brought down to one-fourth its original volume by boiling
during the extraction procedure. Then, the concentrated extract is filtered and used as
such or processed further.
5. Percolation
Percolation is a continuous flow of the solvent through the bed of the crude drug material
to get the extract.
In this process, the powdered drug is moistened with an appropriate amount of the
specified menstruum and allowed to stand for approximately 4 h in a wellclosed
container, after which the mass is packed and the top of the percolator is closed.
Additional menstruum is added to form a shallow layer above

10. the mass, and the mixture is allowed to macerate in the closed percolator for 24 h.
The outlet of the percolator then is opened and the liquid contained therein is allowed to
drip slowly.
Additional menstruum is added as required, until the percolate measures about three-quarters
of the required volume of the finished product.
The marc is then pressed and the expressed liquid is added to the percolate.
Sufficient menstruum is added to produce the required volume, and the mixed liquid is
clarified by filtration or by standing followed by decanting.