I D PHARM CHAPTER 2 of Pharmacognosy Various systems of classification of drugs of natural origin

I D PHARM CHAPTER 2 Pharmacognosy: Various systems of classification of drugs of natural origi

Crude drugs mean collection and drying of unprocessed natural substances obtained in crude from obtained from nature's different sources like the plant, animal, mineral, marine, and biotechnology These unprocessed Crude drugs are further grouped as Organised (cellular) and Unorganised (acellular) drugs Organized drugs are crude drugs represent part of a plant and are, therefore, made up of cells. unorganized drugs are a diverse group of solid and liquid materials which do not consist of parts of plants and are obtained from natural sources by a variety of extraction procedures.

 In pharmacognosy, crude drugs classified according to

I. Alphabetical Classification

II. Taxonomical Classification

III. Morphological Classification

IV. Chemical Classification

V. Pharmacological Classification

VI. Chemotaxonomical Classification

 It is noted that none of them give a total profile of natural drugs and has its limitations.

 1. Alphabetical Classification

Crude drugs arranged according to the alphabetical order of their Latin and English names. Some of the pharmacopeia and reference books classify crude drugs according to this system are as follows eg. Indian pharmacopeia, British pharmacopeia, United States Pharmacopeia, National Formulary British Pharmaceutical Codex, European Pharmacopeia used in Drugs and Cosmetics.

Taxonomy: Practice of classifying plants and animals according to their presumed natural relationships.

II. Taxonomical Classification

Drugs classified according to plants or animals from which they are obtained in phyla, orders, families, genera, species, subspecies, etc. This method of classification is based on considerations of natural relationship or phylogeny among plants or animals. Crude drugs of plant origin are classified on the basis of one of the accepted systems of botanical classification. A large number of plant families have certain distinguishing characteristics that Permit crude drugs from these families to be studied at one time. Thua, drugs obtained from plants having alternate leaves, cymose flowers, and fruits that are berries or capsules (hyoscyamus, datura, belladonna, and stramonium) are considered with other members of Solanaceae. Taxonomical classification of crude drugs derived from dicot plants as follows.

 a. Phylum: Spermatophyta.

b. Division: Angiospermae.

c. Class: Dicotyledons.

d. Order: Rosales.

e. Family: Leguminosae.

f. Sub-family: Papilionaceae.

g. Genus: Glycyrrhiza, Astragalus, Myroxylon.

h. Species: Glycyrrhiza glabra, Astrogolus gummier, Myroxylon balsamum. 

III. Morphological Classification

Crude drugs grouped according to part of plant or animal represented into organized and unorganized drugs. Organized drugs divided into parts of the plants like leaves, flowers, fruits, seeds, woods, barks, subterranean parts like roots, and rhizomes. unorganized drugs are dried latex, gums, extracts, etc.

 Some of the examples of crude drugs under this type of classification are as follows.

a. Seed: Nuxvomica, Strophanthus, Areca. Castor.

b. Leaf: Senna, Digitalis, Vasaha, Eucalyptus.

c. Bark: Cinchona, Kurchi, Cinnamon, Quillia.

d.Wood: Quassia, Sandalwood, Sassafras. Red sanders.

e. Root: Rauwolfia, Ipecacuanha, Aoonite, Jalap.

f. Rhizome: turmeric, ginger, valerian, Podophyllum.

g. Flower: Clove, Pyrethrum, Artemisia, Saffron.

h. Fruit: Coriander, Colocynth. Fennel. Bael.

i. Entire Organism: Ephedra, Ergot, Cantharides, Belladonna.

j. Dried Latex: Opium, Gutta-percha, Papain.

k. Resin combinations: Balsam of Tolu, Myrrh, Asafoetida, Benzoin.

l. Dried Juice: Aloes, Kino, Redgum.

m. Gum: Acacia, Tragacanth, Ghatti gum, Guar gum.

n. Dried extract: Gelatin, Catechu, Agar, Curare.

 This system of classification is more convenient for practical purposes, especially when the chemical nature of the drug is not understood,

 Morphology: The branch of geology that studies the characteristics and configuration and evolution of rocks and landforms.

 IV. Chemical Classification

Crude drugs are divided into groups according to the chemical nature of their constituent. Since pharmacological activity and therapeutic significance of crude drugs based on the nature of their chemical constituents, chemical classification of crude drugs is a perfect method of study. The crude drugs containing alkaloids are grouped, regardless of their morphology and taxonomical behavior.

 Few examples of drugs under chemical classification are as follows.

a. Glycosides: Digitalis, Senna, Cascara, Liquorice.

b. Alkaloids: Nuxvomica, Ergot, Cinchona, Datura.

c. Tannins: Myrobalan, Pale Catechu, Ashoka.

d. Volatile oils: Peppermint, Clove, Eucalyptus, Garlic.

e. Lipids: Castor oil, Beeswax, Lanolin, Cod liver oil.

f. Carbohydrates & Derived products: Acacia, Agar, Honey, Ispaghula

g. Resins and Resin Combinations. Colophony, Jalap, Balsam of Tolu.

h. Vitamins and Hormones: Yeast, Shark liver oil, Oxytocin, Insulin.

i. Proteins and Enzymes: Gelatin, Papain, Trypsin.

Chemical method of classification is preferred for the systematic study of crude drugs, although crude drugs belonging to different morphological or taxonomical categories may be brought together, provided there ie .some the similarity in the chemical nature of principles.

 V. Pharmacological Classification

This system of classification involves grouping of crude drugs according to pharmacological actions regardless of a constituent, morpholog1 taxonomical status or chemical relationship, drugs are grouped,

(a) Laxatives: Aloes, Rhubarb. Castor oil, Ispaghula, Senna.

(b) Cardiotonic-Digitalis, Arjuna.

(c) Carminatives & G.L regulators – Umbelliferous: Coriander, Fennel,  Ajowan, Cardamom Ginger, Black pepper, Asafoetida. Nutmeg. Cinnamon,  Clove.

(d) Astringents-Catechu.

(e) Drugs acting on the nervous system - Hyoscyamus, Belladonna. Aconite,  Ashwagandha. Ephedra, Opium, Cannabis, Nux vomica.

(f) Antihypertensives - Rauwolfia.

(g) Antitussives - Vasaka, Tolu balsam, Tulsi.

(h) Antirheumatics - Guggul, Colchicum.(i) Antitumour - Vinca.

(j) Antileprotics - Chaulmoogra Oil.

(k) Antidiabetics - Pterocarpus, Gymnema, Sylvestro.

(1) Diuretics - Gokhru, Punarnava.

(m) Antidysentrics - ipecacuanha.

(n) Antiseptics and disinfectants Benzoin, Myrrh. Nim, Curcuma.

(o) Antimalarials - Cinchona.

(p) Oxytocics - Ergot.

(q) Vitamines - Shark liver Oil and Amla.

(r) Enzymes - Papaya, Diastase, Yeast.

(s) Perfumes and flavoring agents - Peppermint Oil, Lemon Oil, Orange Oil,  Lemongrass Oil, Sandalwood.

(t) Pharmaceutical aids - Honey, Arachis Oil, Starch, Kaolin, Pectin, Olive oil,

Lanolin, Beeswax, Acacia, Tragacanth, Sodium alginate, Agar, Guar gum,  Gelatin.

(u) Miscellaneous - Liquorice, Garlic, Picrorhiza, Dioscorea, Linseed,  Shatavari, Shankhapushpi, Pyrethrum, Tobacco.

 VI. Chemotaxonomical Classification

The expanding knowledge of the phytochemical screening has revealed the existence of a close relationship between chemical constituents of plants and their taxonomical status. The concept of 'chemotaxonomy’ has brought the plant chemist back to the systematic botany because certain chemical compounds have been found to characterize certain botanical groupings. Chemotaxonomy establishes a relationship between the position of the plant and attempts to utilize chemical facts to obtain a more exact understanding of biological evolution and natural relationships. The knowledge of chemotaxonomy could serve the basis for the classification of crude drugs. The location of berberine alkaloids in Hydrastis, Berberis and, Argemone, distribution of rutin, ranunculaceous alkaloids, and flavonoids in species of higher plants are of chemotaxonomic significance.