introduction

Pharmacognosy
The word "pharmacognosy" is derived from two Greek words pharmakon (drug), and gnosis (knowledge).
It is defined as the study of medicinal drugs derived from plants or other natural sources. It includes the study of the physical, chemical, biochemical and biological properties of drugs, drug substances as well as the search for new drugs from natural sources. It is also defined as the study of crude drugs.
Although pharmacognosy is principally concerned with plant materials , there are some animal products which are traditionally included within the subject such as ( beeswax , gelatin , wool fat ,Vitamins …..etc).other natural products such as antibiotics ,hormones and others may be also involved in addition to marine organisms (Plants & Animals).
The use of modern isolation techniques and pharmacological testing procedures means that the new plant drugs may find their way into medicin as purified substances, but the use of single pure compound is not without limitations.

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 ( Salixالصفصاف ) , Shrub (Catharanthus) .
4- The active constituents from natural sources ( Active groups ) like: (Glycosides, Alkaloids, Volatile Oils, Tannins, etc).
5- The biosynthetic pathway of the active constituents.
6- Storage places of the active constituents in organisms : Leaf (Digitalis):digitalis leaf contains natural derivative called cardioactive glycoside (digitoxin) , Roots ( Liquorice ) , Seeds (Coffee bean), and Bark(Cinnamon).
7- Collection & Storage of the part used.
8- Physical , Chemical & Biological properties of the active constituents.
9- The Correct prescription of natural drug in the treatment of the disease.

Definitions & Basic Principles