PHARMACOGNOSY

DEFINATION

      The term Pharmacognosy has been derived from the 2Greek words: I) pharmakon, which means a drug & ii) gnosis, which means knowledge of or gignosco, which means to acquire knowledge of. Thus the full meaning of the term Pharmacognosy is `knowledge of drugs’ or `to acquire knowledge of drugs’.

Pharmacognosy is the objective study of crud drugs & related substances.

Pharmacognosy is an applied science which is concerned with acquiring knowledge of crud drugs by the application of various scientific disciplines.

SCOPE

      Pharmacognosy is an important branch of Pharmacy, which is concerned with the study of crud drugs & natural products of pharmaceutical importence.

It deals with the scientific study of structural, physical, chemical & sensory characters of crud drugs obtained from plant, animal & mineral source.

It also includes the study of their history, distribution, cultivation, collection, preparation, identification, evaluation, preservation & commerce.

SUBJECT MATTERS OF PHARMACOGNOSY

 Pharmacognosy deals with the study of,

Naturally occurring substances having medical properties

Crud drugs & other natural substances of pharmaceutical importences

Chemical constituents of crude drugs & medicinal plants

Natural substances used as excipients or pharmaceutic necessities in the formulation & preparation of pharmaceutical &medicinal products. These include:

i) colouring & flavouring agents, ii) suspending agents, iii) diluents & disintegrating agents, iv) sweetening agents, v) binders, adhesives, solifyding agents, etc.

SUBJET MATTERS

      Substances, which are used as medical & pharmaceutical practices. Example of which include:

a) fibers & surgical dressings, b) anesthetic acids, c) filtering agents, such as diatomite & asbestos, d) basses & vehicles, such as agar, gelatin, wax, fixed oils & fats.

      Beverages with medicinal constituents, e.g. tea, coffee & cocoa which contain caffeine.

      Spices & condiments, which have medicinal properties, e.g. Cinnamon, Cardamon, Umbelliferous fruits (Coriander, Fennel, Cumin, etc.), Mustard seed, Clove, Ginger, Garlic, etc.

      Vitamins, enzymes, antibiotics, allergens, pesticides, etc.

Medicinal plants. &  Traditional medicine.

HISTORICAL DEVELOPMENT OF PHARMACOGNOSY

      Pharmacognosy is regarded as the mother of all science.

      History of pharmacognosy represents the history of pharmacy & medicine.

      Pharmacognosy had its origin in the health-related activities of the most primitive human race of the remote past.

      The early man sought to alleviate his sufferings of illness & injuries by using plants.

      They acquired knowledge of medicinal properties of plants in the following way:

a)  By guesswork or trial & error

b)  While searching for food

c)  By superficial resemblance between the plant parts & the affected organs, that is, by examining the “Signature of Nature”

d)  By observing other animals instinctive discrimination between toxic & palatable plants

e)  By accidental discovery

      By a combination of all these means the ancient people acquired a considerable volume of knowledge about drugs.

      In course of time a group of people emerged in each community who acquired expertise in collecting, testing & using medicinal plants for treating diseases. These people later became known as `Medicine Men'.

      The Medicine Men monopolized the knowledge of drugs and hide that knowledge in some mysterious incantations. They transferred this secret knowledge only to their trusted predecessors of the successive generations, who gradually increased the volume of knowledge about drugs and their uses.

      Initially the transfer of the acquired knowledge from generation to generation used to be done verbally by the use of signs & symbols. As civilization progressed, transfer and recording of the knowledge were done in writing.

According to recorded history:

      Babylonians (about 3000 BC) had knowledge of large number of medicinal plants and their properties.

      Some of the plants used are still used almost in the same way and for the same purposes.

      The Chinese pharmacopoeia, Pen Tsao, written between 3000 and 2730 BC, includes recipes and therapeutic uses of many Chinese traditional medicines.

      Ebers Papurus, written in 1550 BC, recorded that Egyptians possessed a good knowledge of human anatomy & medicinal uses of hundreds of plants which made them capable of embalming dead bodies for making mummies.

      Many of the present day drugs, such as Henbane, Mandrake, opium, Pomegranate, Caster oil, Aloe, Onion, many fixed oils & fats, were in common use in Egypt about 4500 years ago.

      The earliest plant medicines used in the Ayurvedic system were described around 1200 BC with a list of 127 plants.

      The Greek civilization witnessed a highly developed system of medicine which used medicinal plants and minerals. Arab Muslims further enriched this system and developed the Greco-Arabic or Unani system, which formed the basis of modern Allopathic system of medicine.     

The following people contributed significantly to the gradual development of Pharmacognosy:

      Hippocrates (460-370 BC). He is regarded as the `Father of medicine' for his contribution to human anatomy and physiology. He collected, identified and used a large number of medicinal plants.

      Aristotle (384-322 BC). A student of great philosopher Plato listed more than 500 plants of medicinal importance with their description & uses.                                        

Theophrastus (370-287 BC) collected, identified a large number of medicinal plants and recorded their medicinal properties.

      Dioscorides (1st Century AD), a Greek Physician, published five volumes of a book, entitled `De Materia Madica'  in 78 AD, which described more than 600 medicinal plants with their collection, storage & uses.

      Pliny de Elder (23-70 AD), a Greek botanist, collected and described a large number of medicinal plants with their uses.

      Galen (131-200 AD), a Greek pharmacist-physician, described methods of preparing pharmaceutical formulations containing plant and animal drugs. These methods & his other observations on medicinal plants have been recorded in as many as 20 volumes of books. The present day Galenical preparations or Galenicals are prepared according to those methods.

      So long the same person, the apothecary (pharmacist-physician), used to do all the works of collection, processing, preparation and dispensing of the medicaments (the works of the pharmacist) and also diagnosing the disease and prescribing the drug (the works of the physician).

      With the increase of knowledge of drugs, the volume of work also increased a lot and it become impossible for one person to manage them properly.

Thus at this point pharmacy & medicine started developing along two separate paths:

      a) One group specialized in diagnosing the disease and prescribing the drug and became known as the physicians or doctors;

      b) The other group specialized in collecting, processing, preparing & dispensing the drug and became known as the apothecaries or pharmacist.

In this way, Pharmacognosy progressed gradually and formed the basis and beginning of both pharmacy & medicine.