Introduction to Pharmacognosy By Imon Rahman

Pharmacy& Pharmacist Pharmacy refers to the profession which is concerned with the handling of all aspects of chemical substances referred to as medicine or drugs This includes knowledge of source(whether natural &synthetic), physical & chemical properties, good and bad effects on living organisms (including man), dose &dosage forms, formulation, compounding &manufacturing, quality control & assurance, storage, sale and finally law & ethics governing the manufacture, import, export & usage of drugs or poisons

Pharmacist Pharmacists, also known as druggists are healthcare professionals who practice in pharmacy, the field of health sciences focusing on safe and effective medication use. The role of the pharmacist has shifted from the classical "lick, stick, and pour" dispensary role (that is, "lick & stick the labels, count the pills & pour liquids"), to being an integrated member of the health care team directly involved in patient care.

Pharmacists undergo university-level education to understand biochemical mechanisms of action of drugs, drug uses and therapeutic roles, side effects, potential drug interactions and monitoring parameters. This is mated to education in anatomy, physiology, and pathophysiology. Professional interpretation and communication of this specialized knowledge to patients, physicians and other health care providers are functions which pharmacists provide, and are central to the provision of safe and effective drug therapy.

What is Pharmacognosy? The term 'pharmacognosy' was first coined and used by C.A. Seydler in 1815 in a small book he wrote on crude drugs, entitled "Analecta Pharmacognostica". It was derived from two Greek words: pharmakon, which means 'a drug', and gnosis, which means knowledge of, or gignosco, which means 'to acquire knowledge of. Thus the literal meaning of pharmacognosy is: knowledge of drugs, or to acquire knowledge of drugs. Thus Pharmacognosy may be defined as the objective study of crude drugs and related substances of natural origin to acquire knowledge about their nature and properties. It may also be defined as an applied science which is concerned with acquiring knowledge of all aspects of crude drugs and other natural substances of pharmaceutical importance by the application of various scientific disciplines.

According to the American Society of Pharmacognosy- Pharmacognosy is the study of physical,chemical,biochemical & 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.

In other words, it may be said that Pharmacognosy is an important branch pharmacy, which deals with the scientific study of the structural, physical, chemical, biochemical and sensory characters of crude drugs and related substances of plant, animal and mineral origin. It also includes a study of their history, distribution, cultivation, collection, identification, preparation, evaluation, preservation, use and commerce.

WHAT DO PHARMACOGNOSISTS “DO”? Isolation & characterization of “active constituents” Characterization of the pharmacology of crude extracts & active constituents Evaluation of quality of natural medicines Interdisciplinary relationship with ethnobotany & ethnopharmacology WHAT DO PHARMACOGNOSISTS “DO”?

Scope of Pharmacognosy Pharmacognosy occupies an important place in pharmacy as it deals with the collection, identification, preparation and extraction of a large group of drugs obtained from natural sources, which are used both in orthodox and traditional medicine. The knowledge of the action of a drug (pharmacology) can be utilized successfully only when the identity, physical nature and chemical constituents of the drug are well known, and pharmacognosy supplies this information.

Solubility, reactivity, stability, toxicity, dosage, availability, purity, yield, methods of isolation, purification and identification of the chemicals of natural origin are studied in pharmacognosy, which supplies the general information about them needed by all practicing pharmacists. Thus pharmacognosy, the science of drugs of natural origin, has become a discipline of increased significance in the curriculum of pharmaceutical education. In fact, pharmacognosy formed the basis on which other branches of pharmacy developed. Pharmacology, Pharmaceutical Chemistry and Pharmaceutics are all manifestations and ramifications of this basic science of drugs.

Chemical nature and properties of a chemical substance can be studied and understood, or it can be synthesized or its activity can be modified or improved by a pharmaceutical chemist if he possesses a good knowledge of its source, occurrence and method of isolation and state of purity. Formulation and actual preparation of a pharmaceutical product (pharmaceutics) are dependent on a number of properties, such as solubility, stability, reactivity, etc. of the ingredients. This type of information on substances of natural origin is available to the pharmacist if he possesses a good knowledge of pharmacognosy.

Price of a pharmaceutical product containing natural substances is influenced by the methods of collection, curing, drying and assaying of the ingredients, which are dealt with in pharmacognosy. In addition to the various branches of pharmacy, pharmacognosy is closely related to botany and plant chemistry by the fact that both of them developed as a result of man's interest in plants as sources of food and medicine. Pharmacognosy also shares some grounds with biochemistry. physiology. enzymology, food technology and a number of other fields of science. This wider scope of pharmacognosy entitles pharmacognosists to specialize in taxonomy, anatomy, morphology, phytochemistry, cultivation and conservation of medicinal and poisonous plants.

History of Pharmacognosy History of pharmacognosy can be regarded as the history of pharmacy and medicine, because pharmacognosy had its origin in the health-related activities of the most primitive human race of the remote past.The processes that contributed to the early man's search for cures and selection of the medicament include the following: (i)Guesswork, that is, application of intelligence or natural intuition. (ii)Trial and error, that is, try and then discard, if not useful or repeatedly use, if found beneficial.

Curiosity and search for food contributed considerably to his knowledge about the medicinal and edible plants and their virtues. (iv)‘Signature of Nature', that is, superficial resemblance between the plant parts and the affected organs or some symptoms of the ailment also guided the ancient man in the selection of his drugs. (v) Observations on the animals' instinctive discrimination between toxic and palatable plants might also have helped the primitive man to choose. those plants that were beneficial from nutritive and medicinal standpoints. (vi) The healing powers of some plants were undoubtedlydiscovered by accident.

It is probable that by a combination of these various methods, the ancient people were able to build up a considerable knowledge of medicinal and food plants. The acquired knowledge was transmitted from generation to generation and new information was added to it by the next generation either orally or by some signs and symbol and later on through written language. Gradually a group of people in each generation started specializing in collecting and processing medicinal plants and using them against various diseases. This group of people later emerged as the 'Medicine men' of the earlier civilizations and they monopolized the knowledge of drug plants. They used to hide the knowledge of various drugs in some mysterious incantations, which they also used as charms.

The Chinese pharmacopoeia, the Pen Tsao, written by Emperor Shen Nung (written between 3000 and 2730 BC and appeared around 1122 BC) appears to be the oldest pharmacopoeia on earth. This treatise includes recipes and therapeutic uses of many Chinese traditional medicines. Babylonians (about 3000 BC) appear to have been aware of a large number of medicinal plants and their medicinal properties. Some of the plants they used are still used almost in the same manner and for the same purpose. As evident from Ebers Papyrus (written in 1550 BC) the ancient Egyptians possessed an understanding of the human anatomy and a good knowledge of the medicinal uses of hundreds of plants and animals. Many of the present day important drugs like Opium, Pomegranate, Castor Oil, Aloe, Onion, many essential oils, bile, lard and many others 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 practice of medicine using medicinal plants nourished most during the Greek civilization when many historical personalities practised herbal medicine. *Hippocrates, a physician, is regarded as the father of medicine for this contribution to human anatomy and physiology. He is also known to have collected and identified a number of medicinal plants and practised herbal medicine.His Materia Medica consists of some 300 to 400 medicinal plants. *Aristotle, a philosopher, recorded the properties of more than 500 plants of medicinal importance.

Dioscorides, a physician, published five volumes of a book, entitled 'De Materia Medica' in 78 AD This encyclopedic work described more than 600 medicinal plants including their collection, storage and uses. Galen was a Greek pharmacist-physician,who described hundreds of recipes and formulations of medicinal preparations containing both plant and animal ingredients. These recipes and their methods of preparation and his other observations on medicinal plants have been recorded very accurately in as many as twenty books. The present day 'Galenical pharmacy' is a manifestation of his methods and recipes and the term is used as a tribute to him. The present day allopathic and homeopathic systems of medicine are based on the doctrines expatiated by Galen.

Ancient Arabian physicians and emperors possessed a vast knowledge of medicinal plants. They contributed enormously to the development of modern medicine based on the Greek system In earlier days the apothecary (pharmacist-physician) used to handle the works of both the pharmacist and the physician. As the volume of knowledge of disease, therapeutic uses of medicinal plants and technology of preparation of medicaments increased gradually over the years, it became impossible for a single person to manage these two different aspects of health management. As a result, medicine and pharmacy started emerging along two separate paths, one, group of people specialising in diagnosing the ailment and prescribing the remedy for the patient and another group specialising in collecting, compounding and dispensing the medicament.

Ethnobotany is the study of the relationship between people and plants, field includes studying plants as medicines, alternative methods for healing, as wild foods, as agricultural crops; modes of transportation; as clothing and in the religious ceremonies. Ethnopharmacology is the scientific study correlating ethnic groups, their health, and how it relates to their physical habits and methodology in creating and using medicines.

Egyptians (Ebers papyrus, 1550 BC)

Authors of antiquity Hippocrates (460-377 BC) “The Father of Medicine”

Dioscorides (40-80 AD) “De Materia Medica” (600 medicinal plants)

The Islamic era Ibn Altabari (770850) ” فردوس الحكمه“

Ibn Sina (980-1037) ”القانون في الطب“

Ibn Albitar (1148-1197) ”الجامع لمفردات الأدوية والأغذية“

The era of European exploration overseas (16th and 17th century)

Definitions Drug: The term 'drug' refers to any article, whether natural or synthetic having therapeutic and medicinal properties and used in the diagnosis, cure, mitigation, treatment or prevention of diseases in man and other animals. Crude drug: Crude drugs are natural substances of plant, animal or mineral origin, which possess therapeutic properties and pharmacological actions and which have undergone no treatment other than collection and drying. Traditional medicine: Traditional medicines, when referred to the medicinal products, represent a group of medicinal preparations, which are prepared by ancient technology and according to the age-old wisdom of the medicinal virtues of natural substances and concept of disease, handed down from generation to generation.

Herbal Medicine: The term 'Herbal medicine' refers to some medicinal preparations or compounds which are made of one or more plant drug(s) or medicinal plant(s) or its (their) parts 'and organs and are used in the treatment, cure, mitigation and management of various physical and mental diseases or ailments and external or internal injuries of man and other animals.

Entire organism (plant, animal, organism) Natural products/substances: they can be Entire organism (plant, animal, organism) Part of an organism (a leaf or flower of a plant, an isolated gland or other organ of an animal) An extract or an exudate of an organism Isolated pure compounds

Materia Medica: The term Materia Medica literally means materials of medicine and refers to medicinal substances and products derived from natural sources. Formulary: Formulary is a publication, which contains a list of patent medicines with their ingredients and brief notes on their pharmacological properties, and therapeutic uses, published by the relevant authority of a country as a guide for practitioners of medicine and pharmacy. BDNF (Bangladesh National Formulary), BNF (British National Formulary), NF (American National Formulary) are some of the examples of such Formularies.

Pharmacopoeia: Pharmacopoeia is an official publication, which lists various drugs and therapeutic agents of current use with their monographs and specifies tests and standards for them. Many countries publish their own pharmacopoeias listing all the drugs and therapeutic agents used in that country and specifying required standards for them. British Pharmacopoeia (BP). Monograph: The descriptive material pertaining to' any drug or therapeutic agent or preparation included in the pharmacopoeia is known as the monograph. The monograph of a crude drug generally includes the following information on the drugs: official title, synonym, definition, rubric, description, special conditions of collection or preparation for the market, identity tests, tests for adulterants, method of assay, storage requirements, amount of foreign organic matters, uses and doses.

Official drug: Any substance or drug (crude or prepared), which is included in the current issue of the pharmacopoeia of a country and is officially used for therapeutic purposes, is called an 'official drug'. Unofficial drug: A drug, which has once been recognized as a drug in the pharmacopoeia, but not included in the current issue of the pharmacopoeia or any official Drug literature, is designated as an 'unofficial drug'. Non-official drug: A non-official drug is a substance, which possesses some medicinal properties and is unofficially used for therapeutic purposes, but ·has never been included as a therapeutic item in the pharmacopoeia or any official Drug literature of any country.

Constituents: These are chemical substances that are present in the cells of some plant or animal organs. Constituents that exert some physiological or pharmacological actions on living organisms are referred to as 'active constituents' or 'active principles'. Extractive: The crude mixtures of chemical constituents that are removed from plant or animals by various extraction processes are called extractives. Secondary metabolites: Most of the constituents of plants are represented by the secondary metabolites. These are substances synthesized or produced as by-products by plants during their normal metabolic activities. Apparently they are of no primary use to the plant. They are therefore also regarded as 'waste products' of metabolism, which are usually accumulated in some parts of the plant and most often exert physiological activity on living organisms.

Flora: The term flora refers to the plant population of a particular geographical area or country.' Indigenous: Plants and animals growing or living in their native countries are said to be indigenous to those regions. Naturalised: Plants or animals are said to be naturalised when they grow or live comfortably in a foreign land or in a locality other than their native homes.