General Introduction to Pharmacognosy

Pharmacognosy ( I ) : Lecture ( 1 )

General Introduction : The Scope of Pharmacognosy , Definitions and Basic Principles .

Pharmacognosy : Is the study of medicinal products in their crude , or unprepared form . The word derived from the Greek words Pharmakon (drug) , and gnosis or ( knowledge ) .

Pharmacognosy is a subject o identify or authenticate the plant parts using macroscopical , anatomical & phytochemical characters ,and it includes the study of the physical , chemical , biochemical and biological properties of drugs, drug substances or potential drugs or drug substances of natural origin as well as the search for new drugs from natural sources.

Although pharmacognosy is principally concerned with plant materials , there are some animal products which are traditionally encompassed within the subject such as ( beeswax , gelatin , wool fat ,Vitamins …..etc). In addition to that the antibiotics , hormones and others may be also involved , Marine organisms ( Plants & Animals ) which have special potent pharmacological actions are now paied high attention in the search for new drugs .
There are some materials having no pharmacological action but have interest to pharmacognosists are ( Natural fibers , Flavoring and suspending agents , colorants , disintegrants , stabilizers , and filtering and supporting media . Also there are other materials that have natural associations with the subject are ( Poisonous & Hallucinogenic plants , allergens herbicides , insecticides & molluscicides ) .

Pharmacognosy Science Concerned With Studying the Following Subjects :
1- Taxonomy of plants & the natural sources of drugs .
2- Distribution of natural products in the world .
3- Description of plants such as : Tree ( Salix ) , Shrub(Catharanthus) Perennial ( Peppermint ) .
4- The active constituents from natural sources ( Active groups ) like : ( Glycosides , Alkaloids , Volatile Oils , Tannins , etc ) .
5- The biosynthesis & storage places of the active constituents in organisms ( Plants , animals ….etc ) .
6- The part which used from the natural sources in medicine and pharmacy as : Leaf ( Mint , Digitalis ) , Roots ( Liquorice ) , Seeds ( Coffee bean ) , Bark ( Cinnamon ) .
7- Collection & Storage of the part used .
8- Physical , Chemical & Biological properties of the scribed for a limited duration active constituents .
9- The Correct prescription of natural drug in the treatment of the disease .

Definitions & Basic Principles

Pharmacopoeia : BP ( British Pharmacopoeia ) is a book containing directions for the identification of samples and the preparation of compound medicines and publishing by the authority of a government or medical or pharmaceutical society .

Drug : is a natural or synthetic substance used in the treatment , cure , prevention , or diagnosis of disease or used to otherwise enhance physical or mental well being . Drugs may be prescribed for a limited duration , or on a regular basis for chronic disorders. The drug should be included in the official pharmacopoeia .

Crude Drugs : Are drugs originated from plant , animal kingdom , minerals they contain more amount of active constituent . They do not have any side effects .

Extract : Is a substance made by extracting a part of a raw material , often by using a solvent such as Ethanol or Water . Extracts may be solid as a tinctures or in powder form . ( The aromatic principles of many spices , nuts , herbs , fruits , etc . , and some flowers , are marketed as extracts , among the best known of true extracts being almond , cinnamon , cloves , ginger , lemon , nutmeg , peppermint , pistachio , rose , spearmint , vanilla , violet , and wintergreen .

Extractives ( derivatives ) : This term deals with the principle constituents that found in natural substances by many methods like ( Extraction , distillation …….etc . ) this methods are responsible for the medicinal importance of natural substances and crude with notified these extractives are found whether a. single or mixture constituents .
Ex:
The plant Mint is a ( Natural substance ) , the leaf of this plant ( also natural substance ) , after drying , dried leaf ( also natural substance ) , dried leaf is considered crude when expressed to drying process is stilled as found in nature ( There are no changes have been made to their molecular structure ) . Dried leaves are considered as crude drug when they used to treatment the disease ( like stomach inflation pain ).
Dried leaf when exposed to extraction process , extractives like Menthone ( this is one of the principle constituents in the dried leaf ) . And also this extractive is used to treat the above disease or disorder .

Natural product : is a chemical compound or substance produced by a living organism found in nature that usually has a pharmacological or biological activity for use in pharmaceutical drug discovery & drug design .


Professor Dr. Saad Ali Ihsan
Ph.D. Pharmacognosy & Medicinal Plants

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