Tiêu đề 1. INTRODUCTION, DEFINITION, HISTORY AND SCOPE OF PHARMACOGNOSY.pdf ✅

PHARMD GURU Page 1 DEFINITION: Plants from the natural sources are serves for the benefits of man kinds. The drugs that are procured from natural sources belong to the branch of Pharmacognosy.  Earlier only the external morphological characters were used to identify a drug.  At the beginning, Pharmacognosy had developed mainly on the botanical side, being particularly concerned with the description and identification of drugs, both in their whole state and in powder form.  Modern aspects of Pharmacognosy include not only the crude drugs but also their natural constituents and derivatives. The word Pharmacognosy is derived from the Greek words “Pharmakon” (drug), and “gnosis” (knowledge).  The term Pharmacognosy was used for the first time by the Austrian physician Schmidt in 1811 and 1815 by Crr. Anotheus Seydler, who first coined this term in his dissertation entitled „Analecta pharmacognostica‟.  Pharmacognosy is closely allied to medicine, developed during early 19th century as a branch of Materia Medica and applied biology. Pharmacognosy is the study of drugs having their origin in plant and animal kingdom. The subject Pharmacognosy can also be expressed as an applied science that deals with biological, biochemical, therapeutic and economic features of natural drugs and their constituents. Pharmacognosy is a subject in which plant parts are identified or authenticated using macroscopical anatomical phytochemical characters. Therefore Pharmacognosy is “the science of medicines from natural sources”. In other way, Pharmacognosy is knowledge of the history, distribution, cultivation, collection, selection, preparation, commerce, identification, evaluation, preservation and use of drugs and economic substances that affects the health of men and other animals. INTRODUCTION, DEFINITION, HISTORY AND SCOPE OF PHARMACOGNOSY
PHARMD GURU Page 2 During the 19th century and the beginning of the 20th century, “Pharmacognosy” was used to define the branch of medicine or commodity sciences, which deals with drugs in their crude, or unprepared form. Crude drugs are the dried, unprepared material of plant, animal or mineral origin and they are used as such as they occur in nature without any processing except, drying and size reduction for medicines. Plant originated crude drugs consist of entire plants or their parts. For example, Ephedra and datura are entire plants, senna leaves and podes, nux-vomica seeds, cinnamon and cinchona bark, Rauwolfia roots, clove is a flower bud. Crude drugs may also be obtained by physical processes like drying (opium) or extracting with water (catechu, agar). Several other useful substances affecting the health of animals and human being are also included along with crude drugs in the study of Pharmacognosy but have no pharmacological action. These substances include allergens, flavoring agents, colors, pesticides, immunizing agents, vehicles disintegrants, stabilizers, filtering and supporting media and diagnostic aids. Animal source originated crude drugs include beeswax, gelatin, wool fat, silk, vitamins etc. Some of the mineral originated crude drugs like talc, chalk, bentonite etc. are used in various pharmaceutical preparations. In addition, antibiotics, hormones etc. may also be involved. Marine organisms (plants and animals), which have special potent pharmacological actions, are recent focus in the search for new drugs. Study of the materials obtained from natural sources in pharmakognosie was first developed in Europe especially in German populated areas, while other language areas often used in the book named Materia Medica that taken from the works of Galen and Dioscorides. Drogenkunde (“science of crude drugs”), the German term is also used in the same way. As late as the beginning of the 20th century, Pharmacognosy is still in growing importance, particularly for identification and quality control purposes and resulted rapid development in all other areas in the subject. With above discussion, finally a brief definition of Pharmacognosy is described as: “It is a branch of science and a tool for crude drug standardization which deals with the scientific and systematic study of structural, physical, chemical and
PHARMD GURU Page 3 biological characters and evaluation of crude drugs along with geographical sources, history, method of cultivation, collection and preparation for the market, their proper storage and their application in the improvement of health.” Hence, Pharmacognosy science is concerned with studying the following subjects: 1) Taxonomy of plants and the natural sources of drugs. 2) Distribution of natural products worldwide. 3) Description of plants such as Trees (Cinnamon, cinchona, Salix), shrub, (Vinca), Perennials (Peppermint). 4) The active constituents from natural sources (active groups) like (glycosides, alkaloids, volatile oils, tannins, etc.). 5) The biosynthesis and storage places of the active constituents in organisms (plants, animals etc.). 6) The part used from the natural sources in medicine and pharmacy such as leaf (Senna, Mint, Digitalis), roots (Liquorice), seeds (Nux Vomica, Coffee bean), bark (Cinnamon). 7) Collection and Storage of the part used. To understand the basic concept of Pharmacognosy, some general functions of Pharmacognosist is:  Identification of the drug sources.  Determination of the morphological character.  Investigation of potency, purity, and admixture.  Planning and designing of the cultivation of medicinal plants.  Prescription of the detail processes of collection, drying and preservation.  Knowledge about extraction and isolation procedures.  Knowledge about active constituents, phytoconstituents, chemical nature and uses.  Knowledge about physical, chemical, biological and microbial evaluation of drugs. HISTORY: The early man sought to alleviate his sufferings of illness and injuries by using plants. They acquired knowledge of medicinal properties of plants by guesswork or trial and error, while searching for food, by superficial resemblance between the
PHARMD GURU Page 4 plant parts and the affected organs, i.e., by examining the “Signature of Nature”, by observing other animals, instinctive discrimination between toxic and palatable plants or by accidental discovery. In course of time a group of people emerged in each community who acquired expertise in collecting, testing and using medicinal plants for treating diseases. These people later became known as `Medicine Men‟. 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 medicinal uses. Initially the transfer of the acquired knowledge from generation to generation used to be done verbally by the use of signs and symbols. As civilization progressed, transfer and recording of the knowledge were done in writing. ACCORDING TO OLD HISTORY:  The history of herbal medicine is from the beginning of human civilization. In that era, maximum plant based medicines were used.  Before the beginning of Christian era, many ancient documents revealed that plants were used largely by the Asian namely China, India, Egypt and Greece.  In China, medicinal plants had been in use since 5000 BC. In around 3000 BC, Shen Nung wrote a book on herbal document “Pentaso”which is very old documentary book.  During the same period, meticulous efforts had been progressing in India, for classification of herbs through proper examination.  Finally, Charaka made 50 groups of 10 herbs, each of which was meant for specific diseases whereas Sushrutha enlisted only 760 herbs in 7 groups, based on their common properties.  In India, the medicinal properties of the plants are first described in two Vedas, Rigveda and in Atharvaveda (3500-1500 B.C) from which Ayurveda has developed. The earliest plant medicines used in the Ayurvedic system were described with a list of 127 plants.  The binomial classification of plants, introduced by Swedish botanist Carl Linnaeus in 1700s, was further developed by Bentham and Hooker (1862-1863). Gregor Mendel’s important observations on plant hybrids came in 1865.