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CLASSIFICATION OF CRUDE DRUGS
Introduction
Definition of crude drug
The term “CRUDE DRUG” generally applies to the products from plants and animal origin
found in a raw form.
They are unprocessed form of natural products which are treated for their packing and to
prevent them from deterioration.
Crude drugs are further grouped as Organized (cellular) and Unorganised (acellular),
according to whether they contain a regular organized cellular structure or not.
ORGANISED UNORGANISED As the name indicates, these are the organs of the plants or animals and are made up of cells or definite structure.
These are derived from parts of plants or animals by some process of extraction, followed by purification, if necessary or maybe a pathological product.
These are solid in nature. These are solid/semi-solid/liquid in nature. Botanical or zoological terminology can be used to describe these drugs.
Such terminologies are inadequate but physical characters such as solubility, density, optical rotation, refractive index are important for description.
Microscopic characters are important criteria for identification.
Chemical tests and physical standards are important for their identification.
Eg : Digitalis, cinchona, clove, fennel, jalap, ephedra etc.
Eg: Aloe, Agar, opium, castor oil, beeswax , gum acacia etc.
In pharmacognosy, crude drugs maybe classified according to :
- Alphabetical order
- The taxonomy of plants and animals from which they are derived.
- Their morphology
- The chemical nature of their active constituents
- Pharmacological actions and therapeutic applications.
- Chemotaxonomical status.
ALPHABETICAL CLASSIFICATION
The crude drugs are arranged according to the alphabetical order of their Latin and English
names.
Some of the pharmacopoeia which classify crude drugs according to this system are :
Indian pharmacopoeia British pharmacopoeia British herbal pharmacopoeia United states pharmacopoeia and national formulary European pharmacopoeia British pharmaceutical codex
E.g .: Acacia, benzoin, cinchona, dill, ergot, fennel, jalap, kurchi, ginger, opium, senna, vasaka, wool fat etc.
ADVANTAGE
Easy to identify. Common for all.
DISADVANTAGE
Difficult if there is “change in name “.
MORPHOLOGICAL CLASSIFICATION
The crude drugs are grouped according to the part of the plant/animal represented into organized and unorganized drugs. The organized drugs are divided into parts of plants like leaves, flowers, fruits, seeds, woods, barks and sub-terranean parts like roots and rhizomes. Some of the examples of crude drugs under this type of classification are as follows:
Part of Plant used as crude drug Examples of medicinal Plants Seeds: Nux vomica, Strophanthus, Isabgol, Castor Leaves: Senna, Digitalis, Vasaka, Eucalyptus Barks: Cinchona, Kurchi, Cinnamon, Quaillaia Woods: Quassia, Sandalwood, Sassafras, Red sanders Roots: Rauwolfia, Ipecacuanha, Aconite, Jalap Rhizomes: Turmeric, Ginger, Valerian, Podophyllum Flowers: Clove, Pyrethrum, Artemisia and Saffron Fruits: Coriander, Colocynth, Fennel, Bael
Enitre drugs: Ephedra, Ergot, Cantharides, and Belladonna Dried latices: Opium, Gutta-percha, Papain Resins and resin combinations Balsam of tolu, Myrrh, Asafoetida, Benzoin
Dried juices: Aloes, Kino, Red gum Gums: Acacia, Tragacanth, Ghatti gum, Guar gum Dried extracts: Gelatin, Catechu, Agar, Curare
Advantages: It is more convenient for identification. It gives idea about source of drugs. It gives idea whether it is organized / unorganized.
Disadvantages: During collection, drying & packing morphology of drug changes. They are difficult to study. The chemical content or action of drug is not known.
CHEMICAL CLASSIFICATION
The crude drugs are divided into different groups according to the chemical nature of their most important constituent. The crude drugs containing alkaloids are grouped together regardless of their morphology and taxonomical relationship. Few examples of the drugs and their chemical classification are as follows:
Chemical constituents Example of Medicinal Plants containing them Glycosides: Digitalis, Senna, Cascara, Liquorice Alkaloids Nux vomica, Ergot, Cinchona, Datura Tannins: Myrobalan, Pale catechu, Ashoka Volatile oils: Peppermint, Clove, Eucalyptus, Garlic Lipids: Castor oil, Bees wax, Lanolin Cod liver oil, Kokum butter Carbohydrates and their derivatives:
Acacia, Agar, Guar gum, Pectin, Honey, Ispaghula
Resin and resin combination: Colophony, Jalap, Balsam of tolu Vitamins and hormones: Yeast, Shark liver oil, Oxytocin, Insulin Proteins and enzymes: Casein, Gelatin, Papain, Trypsin
Advantage :
The crude drugs belonging to different morphological or taxonomical categories may be brought together, provided there is some similarity in the chemical nature of active principles.
Disadvantages:
This method does not give any idea about source of drug. Some drugs contain two important chemicals so it is difficult to classify them. e. g. Nutmeg contains volatile oil as well as fat. Cinchona contains glycoside as well as alkaloid.
PHARMACOLOGICAL (THERAPEUTIC) CLASSIFICATION
This system of classification involves the grouping of crude drugs according to the pharmacological action of their chief active constituent or their therapeutic actions. An outline for pharmacological classification of crude drugs is as follows:
DRUGS ACTING ON GIT :
Bitters (appetizers) – Quassia, cinchona, gentian Carminative – cardamom, fennel, mentha, dill Emetics- Ipecac Bulk laxatives – Agar, Isapghula, banana Purgatives – Senna, castor oil Anti-amoebic – kurchi, ipecac For peptic ulcer -liquorice
DRUGS ACTING ON RESPIRATORY SYSTEM:
Expectorants – Liquorice, Vasaka Anti-expectorants: stramonium leaves (atropine) Anti-tussive–Opium (codeine, noscapine) Bronchodilators – Ephedra, Tea leaves
Advantage It gives similarities of constituents between different plant species of same genus and same family.
SEROTAXONOMY
Application of serology in solving the taxonomical problems. Antigen-antibody reaction. Used for expressing similarity & dissimilarities between species, genus or family.
