Pharmacognosy I - Pharm 131 Introduction

# Pharmacognosy I ## Pharm 131 ## Course Teacher: Prof. Dr. Swarnali Islam Khandaker ## H1: Introduction to Pharmacognosy Pharmacognosy has been a part of the healing arts and sciences since mankind first began to treat illness. It has developed from ancient civilizations that used parts of plants...

# Pharmacognosy I ## Pharm 131 ## Course Teacher: Prof. Dr. Swarnali Islam Khandaker ## H1: Introduction to Pharmacognosy Pharmacognosy has been a part of the healing arts and sciences since mankind first began to treat illness. It has developed from ancient civilizations that used parts of plants and animals to concoct various potions to eliminate pain, control suffering, and counteract disease. The term pharmacognosy was introduced in 1815. This name was formed from two Greek words, pharmakon meaning *drug* and gnosis meaning *knowledge*. Therefore, the literal meaning of Pharmacognosy is *knowledge of drugs or pharmaceuticals*. Pharmacognosy is a study of drugs that originate in the *plant and animal kingdoms*. Pharmacognosy is a branch of pharmacy that deals with the basic resources of medicines from nature (*plant & animal*) and their uses as medicaments from ancient times to present day. Pharmacognosy may be defined as an applied science that deals with the *biologic, biochemical, and economic features of natural drugs and their constituents*. In a broad sense, pharmacognosy covers a knowledge of the *history, distribution, cultivation, collection, selection, preparation, commerce, identification, evaluation, preservation and use of drugs and substances that affect the health of humans and other animals*. ### Crude Drugs A crude drug is a natural drug of plant or animal origin that has undergone no treatment other than collection and drying. That is, the quality or appearance of the drug has not been advanced in value or improved in condition by any physical or chemical treatment. For example: *Digitalis leaf, Rauwolfia root etc.* ### Natural Substances The term natural substances refers to those substances found in nature that comprise *whole plants* and herbs and their anatomic parts & constituents; *whole animals* and their anatomic parts & constituents; and substances that have not had changes made in their molecular structure as found in nature. ### Extraction Extraction is a generally accepted method of obtaining the chief principles by dissolving them in a suitable liquid or liquid mixture. The product of the extraction process is known as the *extractive* and is usually a mixture of substances. ### Derivative/ Extractive/ Chief Constituent Crude drugs are not frequently used as therapeutic agents. Rather, their chief principles are separated by various means and are used in a more specific manner. These principles are known as *derivatives* or *extractives*. Derivatives or Extractives are usually crude mixtures of chemical constituents that are removed from plants or animals by various extraction processes. Regardless of whether the derivative or extractive is a single substance or a mixture of substances, it is the *Chief Constituent* of drug. ### Menstruum *Menstruum* is the liquid or liquid mixture (*solvent*) that is used in the process of extraction for dissolving the chief principles. ### Marc *Marc* is the undissolved portion of the drug that remains after the extraction process is completed. ### Geographic Source and Habitat The geographic source and habitat are the region in which the drug-producing plant or animal grows. ### Plants: Indigenous and Naturalized Plants growing in their native countries are said to be *indigenous* to those regions, such as *Pinus palustris* in the southern United States. Plants are said to be *naturalized* when they grow in a foreign land or in a locality other than their native homes, such as *Datura stramonium*, which was introduced into the United States from Europe. ### Natural drug/Semi-synthetic drug/ Synthetic drug In some instances, drug constituents have been partially replaced in commerce by synthetic compounds of identical chemical structure and therapeutic properties; such natural and synthetic substances often can be distinguished by physical and chemical tests. For example, natural camphor is obtained from the camphor tree by steam distillation; it is dextrorotatory in its reaction to polarized light. In contrast, synthetic camphor may be manufactured by either of two methods: by total synthesis from vinyl chloride and cyclopentadiene (*a completely synthetic process*) or by semi synthesis from pinene derived from pine stumps (*not entirely a synthetic process but a chemical modification of a natural product*). Synthetic camphor is racemic and can be differentiated easily from the natural form. Epinephrine, caffeine, codeine, ephedrine, menthol, penicillin, and other chemicals may also be obtained from either the natural source or by partial or total synthesis. They are considered a definite part of pharmacognosy.