CRUDE DRUGS AND THEIR CLASSIFICATION

SOURCES OF CRUDE DRUGS

They may be obtained from

vegetable, animal and mineral

sources.

They form the subject matter of

Pharmacognosy.

Pharmacognosy is concerned mainly

with naturally occurring substances

of medicinal importance.

It is, however, not entirely limited to

such substances.

Others may include substances such

as;

Surgical dressings prepared from

natural fibres

Flavouring and suspending agents

Disintegrants

The term crude drug refers generally to

products of plant and animal origin found

usually in their raw state/form

The term may also apply to

pharmaceutical products obtained from

the mineral kingdom.

DEFINITION OF CRUDE DRUG

Crude drugs may be defined as any natural

product that has not been advanced in

value or improved in condition by any

process or treatment beyond that which is

essential for its proper packing and

prevention from deterioration.

SOURCES OF CRUDE DRUGS

The most important natural sources of

drugs are;

Higher plants

Microbes

Animals

Marine organisms

TYPES OF CRUDE DRUGS

2 types exist depending on this type of

classification;

1. Organized drugs

2. Unorganized drugs

ORGANIZED DRUGS

These are drugs obtained from the direct

parts of the plants and containing cellular

tissues

E.g. Rhizomes, barks, leaves, fruits, entire

plants, hairs and fibres

EXAMPLES OF ORGANIZED DRUGS

Leaves– Digitalis, Eucalyptus, Mint, Senna,

Spearmint, Squill, Tulsi, Vasaka, Coca, Buchu,

Hyoscyamus, Belladonna, Tea.

Barks–Cascara, Cassia, Cinchona, Cinnamon,

Quillia.

Flowering parts– Clove, Pyrethrum,

Chamomile.

Fruits– Anise, Bitter Orange peel, Capsicum,

Caraway, Cardamom, Coriander, Dill, Fennel,

Lemon peel, Star anise.

Seeds– Bitter almond, Black Mustard,

Cardamom, Colchicum, Ispaghula,, Linseed,

Nutmeg, Nux vomica.

Roots and Rhizomes– Colchicum corm,

Dioscorea, Garlic, Ginger, Ginseng,

Glycyrrhiza.

UNORGANIZED DRUGS

These are drugs which are prepared from

plants by some intermediate physical process

such as incision, drying or extraction and not

containing any cellular plant tissue

E.g. Aloe, honey, beeswax, essential oil

DIFFERENCES BETWEEN ORGANIZED AND UNORGANIZED DRUGS

Organized Drugs Unorganized Drugs

These may be of plant or animal origin.

These may be of plant, animal or mineral origin.

These are direct part of plants or animals.

These are the product of plant or animals.

These have well defined cellular structure.

These do not have well defined cellular structure.

Generally identified by morphological character.

Generally identified by organoleptic properties.

IMPORTANCE OF CRUDE DRUGS

Plant-derived medicines are useful

therapeutic options and often provide a safe

form of therapy.

Provide lead compounds for the development

of new drugs.

CLASSIFICATION

Classification of crude drugs may include;

Alphabetical classification

Morphological classification

Pharmacological classification

Chemical classification

Taxonomic classification

Pharmacological classification

CHARACTERISTICS OF AN IDEAL SYSTEM OF CLASSIFICATION

An ideal method of classification of crude

drugs should be;

Simple

Easy to use

Free from confusion and ambiguities

1. ALPHABETICAL CLASSIFICATION

Alphabetical classification is the simplest

way of classification

Crude drugs are arranged in alphabetical

order of their:

Botanical names

Common names

Local/ vernacular names

The following pharmacopoeia classify

crude drugs according to this system:

British Pharmacopoeia

British Herbal Pharmacopoeia

Ghana Herbal Pharmacopoeia

United States Pharmacopoeia and National

Formulary

European Pharmacopoeia

ADVANTAGES OF ALPHABETICAL SYSTEM OF CLASSIFICATION

It is easy and quick to use

There is no repetition of entries and is

devoid of confusion.

In this system location, tracing and addition

of drug entries is easy

DISADVANTAGE

There is no relationship between previous

and successive drug entries

E.g. Acacia, Benzoin, Cinchona, Dill, Ergot,

Fennel, Gentian, Hyoscyamus, Ipecacuanha,

Jalap, Kurchi, Liquorice, Mints, Nuxvomica,

Opium, Podophyllum, Quassia, Rauwolfia,

Senna, Vasaka, Wool fat, Yellow bees wax,

Zeodary.

2. MORPHOLOGICAL CLASSIFICATION

In this system, the drugs are arranged

according to the morphological or external

characters of the plant parts or animal parts.

i.e. which part of the plant is used as a drug

e. g. leaves, roots, stem

3. PHARMACOLOGICAL CLASSIFICATION

This involves grouping of drug according

to their pharmacological action.

This is also referred to as therapeutic

classification of drugs.

Drugs like digitalis, squill and

strophanthus having cardiotonic action

are grouped together irrespective of their

parts used or their phytoconstituents.

CLASSIFICATION OF DRUGS BASED ON PHARMACOLOGICAL ACTION

Pharmacological Action Drugs

Anticancer Vinca, Podophyllum, Taxus

Anti-inflammatory Colchicum, Turmeric

Antiamoebic Ipecac root, Kurchi bark

Antiasthmatic Ephedra, Lobelia

Anthelminthic Male fern, Quassia wood

Antispasmodic Datura, Hyoscyamus

Astringent Catechu

Analgesic Opium, poppy

Bitter tonic Quassia wood, Nux-vomica, Gentian

Carminatives Coriander, fennel, clove, peppermint

Purgatives Senna, Rhubarb

Expectorant Tulsi, Balsam of Tolu

Cardiotonic Digitalis, Squill, Strophanthus

Tranquilizers Rauwolfia Roots

ADVANTAGE

This system of classification can be used for

suggesting substitutes of drugs if they are not

available at a particular place or point of time.

DISADVANTAGE

Drugs having different action on the body gets

classified separately in more than one group that

causes ambiguity and confusion.

E.g. Cinchona is an antimalarial drug because of

presence of quinine but can be put under the group

of drug affecting heart because of antiarrythymic

action of quinidine.

CHEMICAL CLASSIFICATION

The crude drugs are divided into different

groups according to the chemical nature

of their relevant constituent.

The chemical classification of drugs is

dependent upon the grouping of drugs

with identical constituents.

CHEMICAL CLASSIFICATION

1. Carbohydrates

Gums - Acacia, Tragacanth, Guargum

Mucilages - Plantago seed

Others include Starch, Honey, Agar, Pectin,

Cotton

2. GLYCOSIDES

Anthraquinone Glycosides - Aloe, Cascara,

Rhubarb, Senna

Saponins Glycosides - Quillaia, Arjuna,

Glycyrrhiza

Cyanogenetic Glycosides - Cassava

Isothiocyanate Glycosides - Mustard

Cardiac Glycosides - Digitalis, Strophantus

3. TANNINS

Tannins are astringent, bitter plant based

polyphenols that either bind or precipitate

proteins.

The astringency from tannins causes a dry

and puckery feeling in the mouth.

E.g.- Guava, Tea

4. VOLATILE OILS

Monoterpenes and sesquiterpenes

obtained from plants.

Examples- Cinnamon, Fennel, Dill,

Caraway, Coriander, Cardamom,

Orange peel, Mint, Clove

5. LIPIDS

Fixed oils – Castor, Olive, Almond, Shark

liver oil

Fats – Theobroma, Lanolin

Waxes – Beeswax, Spermaceti

6. ALKALOIDS

Nitrogenous substances of plant origin

Pyridine and Piperidine – Lobelia,

Nicotiana

Tropane - Coca, Belladonna, Datura,

Stramonium, Hyoscyamus, Henbane

Quinoline – Cinchona

Isoquinoline – Opium, Ipecac, Calumba

Indole – Ergot, Rauwolfia

Amines – Ephedra

Purine bases – Tea, coffee

TAXONOMIC CLASSIFICATION

Based on an accepted system of system of botanical classification

Grouped into:KingdomPhylum OrderFamilyGenusSpecies

ADVANTAGES

Allows for precise and ordered arrangement of drugs.

Accommodates any drug without ambiguity

MAJOR PLANT DRUGS CURRENTLY USED IN MEDICINE

DRUG PLANT SOURCE USE(S)

Vinblastine Catharanthus roseus

Anticancer

Vinblastine Catharanthus roseus

Anticancer

Reserpine Rauvolfia serpentina

Antipsychoyic, antihypertensive

Quinine Cinchona sp. Antimalarial,amoebic dysentery

Pilocarpine Pilocarpus jaborandi

Antiglucoma

Cocaine Erythroxylum coca

Topical anesthetic

DRUG PLANT SOURCE USE(S)

Codeine Papaver somniferum

Antitussive

Atropine Atropa belladonna

Spasmolytic

Artemisinin Artemesia annua

Antimalarial

Taxol Taxus baccata, T. brevifolia

Breast and ovarian cancer

Allicin Allium sativum Antifungal, amoebiasis

Morphine Papaver somniferum

Narcotic analgesic

MEDICAL TERMINOLOGIES

Arthritis -Inflammation of a joint

Ascites -Abnormal accumulation of fluid in

the peritoneal cavity

Asphyxia -Inability to breath

Atrophy -Wasting of a tissue or organ

Carcinogenic- Causing cancer

MEDICAL TERMINOLOGIES

Carcinoma- A malignant epithelial tumour

eventually becoming fatal

Cardiotonic- An agent that has a

stimulating effect on the heart; increasing

the strength and tone of the heart.

Cardiac depressant- Slowing the action of

the heart

Carminative Drug- causing the release of

stomach or intestinal gas

MEDICAL TERMINOLOGIES

Cathartic -Having the power of cleaning the

bowels-purgative

Decongestant - Relieving congestion, as of

the mucous membrane

Demulcent – Soothing action on inflammed

mucous membranes

Dermatitis - Irritation or inflammation of the

skin

MEDICAL TERMINOLOGIES

Diuretic - Promoting the flow of urine

Dysmenorrhoea - Difficult or painful

menstruation

Dyspepsia – Difficulty in digestion

Dysuria - Difficulty or pain while passing urine

Emetic -Causing vomiting

MEDICAL TERMINOLOGIES

Expectorant - Aiding the secretion of the mucous

membrane of the air passages and the removal of

fluid

Febrifuge - Anything which reduces fever

Haematemesis - Vomiting of blood

Haematuria - The presence of blood in the urine

Heamatinic: Therapeutic agent that causes

increase in the heamoglobin content of the blood.

MEDICAL TERMINOLOGIES

Insomnia: Difficulty in sleeping or staying

asleep.

Mydriatic: Drug that causes dilatation of the

pupil.

Sternutatory: a substance that causes

sneezing

Vermifuge: a remedy that causes expulsion

of worms or parasites.

Xerostomia: Anbormal dryness of the mouth