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Plant Nomenclature & Taxonomy

الكلية كلية الصيدلة     القسم فرع العقاقير والنباتات الطبية     المرحلة 2
أستاذ المادة سعد علي احسان الاعرجي       4/23/2011 1:46:01 PM

Pharmacognosy 

 

Lecture  ( 4 )

 

 

 

Plant Nomenclature & Taxonomy

 

 

Plants nomenclature now depends on the binomial system that belong to the Swedish biologist Linnaeus ( 1707- 1778 ) , in which the first name denotes the the genus that begins with a capital letter , while the second denotes the species and begins with a small letter .Ex: Mentha piperita

 

The Following example showing the systematic position of peppermint ,  ( Mentha piperita ) :

 

Division :  Angiospermae

 

Class  :  Dicotyledoneae

 

Sub class : Sympetalae

 

Order  : Tubiflorae

 

Sub order : Verbenineae

 

Family : Labiatae ( Lamiaceae )

 

Sub family : Stachydoideae

 

Tribe : Satureieae

 

Genus : Mentha

 

Species : Mentha piperta Linnaeus ( Peppermint )

 

Varieties : Mentha piperita var. officinalis Sole ( White Peppermint )

 

                  Mentha  piperita var. vulgaris   Sole   ( Black peppermint )

 

We must notice that in the Pharmacopoeias & in research publications botanical names are followed by the names of the Scientists or botanists who first described the plant species or variety e.g. ( Linnaeus & Sole ) as in case of peppermint given above .

 

1-     Alphabetical Classification :

 

Alphabetical classification is the simplest way of classification of any disconnected items . Medicinal plants are arranged in alphabetical order of their Latin & English names ( common names ) or sometimes local language names ( Vernacular names ) . Some of the pharmacopoeias , dictionaries , and reference books which classify medicinal plants /crude drugs according to this system are as follows :

 

1-     Indian pharmacopoeia

 

2-     British      =

 

3-     British herbal   =

 

4-     United States pharmacopoeia & National Formulary

 

5-     British pharmacopoeia Codex

 

6-     European pharmacopoeia

 

In European pharm. These are arranged according to their names in Latin where in U.S.P. & B.P.C. these are arranged in English.

 

2-     Morphological Classification :

 

     _______________________________

 

In this system , the medicinal plants are classified in groups according to the plant parts that used as a drug for healing the disease , and summarized as follow :-

 

A)   The Arial plant parts as :

 

1-     The Herb ( all the aerial vegetative parts )

 

Ex: Spearmint , Peppermint

 

2-     The Leaves , ex : Tea , Digitalis , Senna

 

3-     The Steams , ex : Pine , Zizyphus

 

4-     The bark , ex : Salix , Cinnamon

 

B)   The Sexual Organs , as :

 

1-     Flowers , ex : Orange , Lemon

 

2-     Seeds , ex : Coffee bean , Sweet almond .

 

3-     Fruits ,  ex : Pomegranate , Papaver .

 

4-     Stigma of the flowers , ex : Crocus .

 

5-     Flower buds , ex : Clove , Rose .

 

C)   The ground parts :

 

1-     True roots , ex : Rauwolfia

 

2-     Bulbs , ex : Squill bulbs , Allium

 

3-     Corms , ex : Colchicum , Crocus

 

4-     Tubers , ex : Potato , Salep

 

5-     Rhizomes , ex : Glycyrrhiza

 

 

3-     Chemical Classification :

 

_________________________    

 

       In this system the medicinal plants are divided in to different groups      according to the chemical classification of drugs nature of their most important constituents . Since the pharmacological activity and therapeutic significance of crude drugs are based on the nature of their chemical constituents . The chemical classification of drugs is dependent upon the grouping of drugs with identical constituents . an out of this classification is as follows :

 

1-     Carbohydrates : Carbohydrates are polyhydroxy Aldehydes or Ketones containing an unbroken chains of carbon atoms . ex :

 

  Gums -  Acacia , Tragacanth , Guar gum 

 

  Mucilages -  Plantago seeds , Spearmint roots

 

  Others - Starch ,  Honey , Agar , Pectin , Cotton

 

2-     Glycosides : Glycosides are compounds which upon hydrolysis give rise to one or more sugars ( glycone ) and non- sugar ( aglycone = genine ) , ex :

 

Anthraquinone Glycosides : Aloe , Cascara , Rhubarb , Senna

 

Saponin Glycosides : Quillaia , Arjuna , Glycyrrhiza

 

Cyanophore Glycosides : Wild cherry bark

 

Isothiocyanate Glycosides : Mustard

 

Cardiac Glycosides : Digitalis , Strophantus

 

Bitter Glycosides : Gentian , Calumba , Quassia , Chirata

 

3-     Tannins – Tannins are complex organic , non – nitrogenous derivatives of polyhydroxy benzoic acids , ex : Pale catechu , Black catechu , Ashoka bark , Galls , Myrobalan , Bahera , Amla

 

4-     Volatile Oils – Monoterpenes & Sesquiterpenes obtained from plants ex : Cinnamon , Fennel , Dill , Caraway , Coriander , Cardamom , Orange peel , Mint , Clove , Valerian

 

5-     Lipids :  Fixed oils – Castor , Olive , Almond , Shark liver oil

 

                   Fats – Theobroma , Lanolin

 

                   Waxes – Bees wax , Spermacetic

 

6-     Resins – Complex mixture of compounds like  resinols , resin acids , resinotannols , resenes . ex : Colophony , Podophyllum , Cannabis , Jalap , Capsicum , Turmeric , Balsam of Tolu , and Peru , Asafoetida , Myrrh , Ginger .

 

7-     Alkaloids : Nitrogenous substances of plant origin ex :

 

Pyridine & Piperidine _ Lobelia , Nicotiana

 

Tropane – Coca , Belladonna , Datura , Hyoscyamus , Henbane .

 

Quinoline – Cinchona

 

Isoquinoline – Opium , Ipecac , Calumba

 

Indole – Ergot , Rauwolfia

 

Amines – Ephedra

 

Purina – Tea , Coffee

 

8-     Protein – Gelatin , Ficin , Papain

 

9-     Vitamins – Yeast

 

10-Triterpenes – Rasna , Colocynth

 

 

This system is based on the existence of relationship between constituents in various plants . There are certain types of chemical constituents that characterized certain classes of plants .This gives birth to entirely new concept of chemotaxonomy that utilizes facts / characters for understanding the taxonomical status , relationships and the evolution of the plants . For example , tropane alkaloids generally occur among the members of Solanaceae thereby , serving as a chemotaxonomic marker . Similarly other secondary plant metabolites can serve as the basis of classification of crude drugs .

 

The berberine alkaloid in berberis & Argemone ; Rutin in rutaceae members , rannunculaceous alkaloids among its members etc are other example .

 

 

In this system the medicinal plants are arranged in groups according to their therapeutic uses such as :

 

1-     Laxatives , ex : Senna , Castor oil , Aloe

 

2-     Cardiac Tonics plants , ex : Digitalis , Squill bulbs .

 

3-     Anthelmentic , ex : Pomegranate

 

4-     Sedative & Narcotic , ex : Papaver , Datura

 

5-     Stimulants , ex : Tea , Coffee bean

 

6-     Carminatives , ex : Spearmint , Peppermint

 

7-     Anti – Rheumatismic plants , ex : Salix , Black mustard

 

8-     Nutrient plants , ex : Allium , Citrus .

 

 

6-     Commercial classification :

 

__________________________

 

 This kind of classification is depended on commercial bases that are deliberation in the commercial markets where these plants are arranged in groups according to real uses in the commercial markets and as follows :

 

1-     Mineral plants : These plants are selling for using in healing diseases.

 

2-     Condiments , Spices , Flavoring agents and Coloring matters : Most of these plants are medicinal , but they are selling under the list ( Nutrient plants for human ) , these plants also have a special properties different in their important as a medicinal plants , ex :

 

-         Condiment plants :  White & Black mustard .

 

-         Spices plants :  Black pepper

 

-         Flavoring agents : Cardamom

 

-         Coloring matters : Crocus

 

3-     Aromatic Plants : They are medicinal plants because they containing volatile oils and they use for preparing perfumes & Cosmetics , like Mint ,Thymus , Rose , Jasmine , etc .

 

4-     Insecticides Plants : These plants containing compounds used for killing insects like Pyrethrum plant , Red Squill bulbs , Henna plant .

 

5-     As a Beverages :There are some medicinal plants used as a beverages like:  ( Coffee , Tea , Coco , Cola , Mint ) but in specific properties .

 

 

7- Taxonomical Classification :

 

__________________________

 

 In this system the classification of plants depends on many plant characters such as : ( Morphology , Anatomy , Chemical constituents , Histological …….etc. ) . In this system the plants are arranged in to Phylum , then in to _____ Classes , in to _______ Families , then in to ______ Genus _____ Species and last in to Varieties .

 

 

1-     Plant Kingdom  

 

2-     Phylum

 

3-     Order

 

4-     Family

 

5-     Genus

 

6-     Species

 

7-     Variety

 

Generally the medicinal plants in this system are divided in to :-

 

 These plants are characterized by the following :

 

A)   They are either very small ( Microorganisms ) consists of one cell to a few cells and these we can see by microscope , or these plants consisting of many cells and those can see by the human eye .

 

B)   These plants have simple growth because its rising from division & enlargement of their cells and those plants haven’t differentiation organs like ( Leaves , Branches , Flowers , Roots , etc..) , example of these plants :-

 

1-     Algae : - as :  Gracilaria conferoides

 

2-     Fungi : - as :  Pencilillium  natatum

 

3-     Lichens : - as : Everina  prunserier

 

4-     Bryophytes : - as : Sphagnum  cymbifolium

 

5-     Pteridophytes : - as : Adiantum  capillus

 

 

These plants consist of many differentiation tissues & organs like        ( Leaves , Flowers , Roots , Seeds …etc. ) . These plants have growth process & differentiation and all of these are named the ( Morphologenesis or development ) , we can see these plants in the nature as ( Trees , Shrubs , Herbs … etc ) .

 

Generally all these plants are divided in to ( Two Phylum ) :

 

P1 : Gymnosperma   ,  P2 : Angiosperma

 

P1 : is divided in to two Orders ( Classes ) : -

 

O1 : Conifers  ,  O2 : Gnetales

 

Each order is consist of many families , ex : the families which contain medicinal plants are :

 

P- Gymnosperma

 

O- Conifers

 

F- Pinaceae

 

G- Pinus

 

S- pinaster   ( Pinus pinaster )

 

P- Gymnosperma

 

O- Gentales

 

F- Genetaceae

 

G- Ephedra

 

S- sinica         ( Ephedra sinica )

 

The phylum Angiosperma , most of the medicinal plants belong to this phylum , and its divided in to two orders ( Classes ) :

 

O1 : - Monocotyledoniae  ,    O2 : - Dicotolydoniae

 

Each order is consist of many families : -

 

O1 – Monocotyledoniae

 

F : - Liliaceae

 

G - Aloe

 

S-  vera    ( Aloe  vera )

 

O1 : - Monocotyledoniae

 

F : - Iridaceae

 

G - Crocus

 

F : sativus   ,  ( Crocus  sativus )

 

O2 : Dicotyledoniae

 

F : Scrophulaceae

 

G : Digitalis

 

S : purpurea   ,   (  Digitalis  purpurea  )

 

O2 : Dicotyledoniae

 

F : Papaveraceae

 

G : Papaver

 

S : somniferum   ,  (  Papaver  somniferum  )

 

          Dr. Saad A. Ihsan

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