Pharmacognosy, derived from the Greek words “pharmakon” (drug) and “gnosis” (knowledge), is probably the oldest modern science, and generally the study of crude drugs of plant and animal origin (in the form of tinctures, teas, poultices, powders, and other herbal formulations), and it incorporates authentication and quality control of such drugs, based on macroscopic and microscopic examinations of crude drugs. The term Pharmacognosy was first introduced by the Austrian physician Schmidt in 1811 and then in 1815 by Seydler in a work titled Analecta Pharmacognostica.
Like any other scientific area, since the introduction of Pharmacognosy some 200 years ago, it has evolved over the years, and now Pharmacognosy can be defined as the science of biogenic or naturally derived drugs, pharmaceuticals, and poisons, and it incorporates various modern analytical techniques to authenticate and quality control of crude drugs as well as purified active extracts, fractions, and components, and even medicinal foods. Drug use from medicinal plants has advanced from the formulation of crude drugs to the isolation, identification, and assessment of bioactivity of active compounds in drug discovery, and so has the subject of Pharmacognosy. The American Society of Pharmacognosy defines Pharmacognosy as “the study of the physical, chemical, biochemical and 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.” Modern Pharmacognosy involves the broad study of natural products from various sources including plants, bacteria, fungi, and marine organisms.
Pharmacognosy has always been a translational or multidisciplinary science, and during the evolution of the scope of this subject area, phytochemistry and phytochemical analysis have become integral parts of Pharmacognosy. Molecular biology has become essential to medicinal plant drug discovery through the determination and implementation of appropriate screening assays directed toward physiologically relevant molecular targets, and modern Pharmacognosy also encapsulates all these relevant new areas into a distinct interdisciplinary science.
The emphasis and focus of research in Pharmacognosy have changed significantly, from focusing on identification of drugs, including the isolation of active principles, and more recently, the investigation of biological activity. Research into ethnobotany, ethnomedicine, and ethnopharmacology has also become an important element in Pharmacognosy.
Pharmacognosy has played a pivotal role in the discovery and development of new drugs and therapies, and has been continuing to do so even today. It also formed the basis of the development of the subject “Pharmacy.” However, it is rather unfortunate that Pharmacognosy is somewhat neglected nowadays as a major subject area within the modern Pharmacy curricula, especially in the West. For the sake of new hypes of modern medicine, one should not forget the usefulness traditional medicines based on plants. It has never been more important for any modern pharmacist to have proper knowledge about traditional medicines. One of the best examples of the usefulness of not neglecting indigenous herbal remedies is Artemisia annua (common name: qinghaosu), which has long been used in China for the treatment of intermittent fever or malaria. Extracts from this plant were studied in the West from the 1980s onward, resulting in the development of a new class of effective antimalarials, the artemisinins.
While the word Pharmacognosy may not be that visible in the Pharmacy curricula in the UK and USA, some of its contents are still present in various forms and names, e.g., drug discovery from natural products/medicinal plants, herbal therapy, phytotherapy, natural medicines, and phytopharmaceuticals. Despite all odds, the popularity and applications of Pharmacognosy are ever increasing in countries like Brazil, China, and India, the emerging giant economies where Pharmacognosy research has gained new momentum because of its proven potential in contributing billions of dollars to their economy. Historically, natural products discovered from medicinal plants and their derivatives have provided numerous clinically useful medicines. Despite the challenges facing drug discovery from medicinal plants, natural products isolated from medicinal plants will remain an essential component in the search for new drug candidates.
Current research in drug discovery from medicinal plants involves a multifaceted approach combining botanical, computational, phytochemical, biological, and molecular techniques. It is evident that drug discovery from medicinal plants continues to provide new and important leads against various pharmacological targets including cancer, HIV/AIDS, Alzheimer's, malaria, and pain. Several natural product drugs of plant origin have either recently been introduced or are currently involved in late-phase clinical trials.
Whether we like it or not, Pharmacognosy is not a subject of the past, but it has evolved and developed over the years to adapt itself with the changing environment, and is now fit to meet the challenges of the present and the future of drug discovery and development. Thus, the importance of Pharmacognosy in Pharmacy cannot be overemphasized. Pharmacognosy will remain to be a significant and an essential contributor to the knowledge and understanding of drugs and therapies, and thus should be an integral part of any meaningful academic Pharmacy programs world over.
Nature has provided all the needs of human including medicines for better health. It includes complete cure for almost all type of ailments of mankind. The knowledge and experience accumulated over thousands of years has given birth to today’s modern medicine system. More than sixty percent of world population, directly or indirectly still uses natural products for their primary healthcare needs.
Pharmacognosy is systematic study of these crude drugs obtained from natural origin like plant, animal and minerals. Pharmacognosy can be defined as branch of science which involves detail study of drugs obtained from natural origin including name, habitat, collection, cultivation, macroscopy, microscopy, physical properties, chemical constituents, therapeutic actions, uses and adulterants. The word pharmacognosy is derived from two words, pharmakon means medicine (drug) and gignosco means to acquire knowledge of something.
Prof. John Schimidt coined the term pharmacognosy in his book Lehrbuch der Materia Medica. Earlier subject was known as ‘Materia medica’. It includes systematic study of crude drugs from nature. Study of pharmacognosy includes the history, distribution, cultivation, collection, processing and preservation. It also includes the study of physical, chemical and structural characters and the safe uses of crude drugs. In short, pharmacognosy is study of drugs from natural origin. Drugs from natural origin can be obtained by plants, animals (terrestrial as well as marine) and minerals.
The word phytopharmaceutical is derived from Greek word ‘phyton’ means plant. Phytopharmaceuticals are drugs whose active constituents are exclusively plant based and are used in rational phytotherapy. Isolated plant constituents like taxol, morphine, quinine, digoxin, caffeine as well as drugs which are based on homoeopathic are not considered as phytopharmaceuticals.
History and development of pharmacognosy:
The history of pharmacognosy is as old as human existence. To know the future one should know the past. The word ‘drug’ is derived from Latin term Droog means dried, when dried plants were commonly used as medicine. Broadly, history of pharmacognosy can be classified into three major stages. First stage before eighteenth century, very few documents and recorded evidences are available showing use of natural products by human. Second stage involves nineteenth century, which is the time when basic subject has evolved. In this century, the name pharmacognosy came into practice. Initially the subject was more likely to descriptive botany of medicinal plants. But as the time progress, it changes the course and encompasses extraction, isolation and other advances techniques. In twentieth century, which may be considered as third stage of development, series of discoveries resulted in complete metamorphosis of the subject. From last two decades, pharmacognosy is studied in more systematic manner. As herbal wave continue to sweep the world, importance of natural product is at the pinnacle. People are expecting natural products to fit in modern framework. As a result of this there are series of new herbal formulations in the market.
The ancient Egyptians documented their knowledge about medicine on paper made from Cyperus aquaticus commonly called acquatic sage or papyrus. Papyrus Ebers (around 1500 BC), Papyrus, Edwin Smith Paprus, Kahun Medicak Papyrus are some of the oldest handbooks which contain information of illness and treatments. In ancient and clay tablets were used to document knowledge of drugs which are dating back to 3000 BC. Ancient , information about drugs was documented in several Ayurvedic texts which still exist. Apart from Atharvaveda there are several books like Charak Samhita, Sushrut Samhita, Astang Hridaya, Madhav Nidan and Bhava Prakash.
In eighteenth century, pharmacognosy was much closely related to botany. In old days, drugs from natural origin were used in crude form as powder or decoction. Later in nineteenth century, development in science has expanded arena of pharmacognosy. Now a day’s pharmacognosy has become a kind of multidisciplinary subject which embarrasses phytochemistry, analytical pharmacognosy, pharmacotherapy, medicinal plant biotechnology, herbal formulations and nutraceuticals. Zoopharmacognosy is branch of pharmacognosy which involves observation of animal behavior for discovery and development of new drugs. Now a day’s drug from natural origin are studied, formulated and regulated in the framework of modern medicine. More detailed record and history of medicine can be studied from the website of US National Library of medicine on following website www.nlm.nih.gov/hmd/medieval/arabic.html
Scope of pharmacognosy:
Pharmacognosy is critical in development of different disciplines of science. A pharmacognosist should possess a sound knowledge of the terms used to describe the vegetable and animal drugs as covered under botany and zoology, respectively. The knowledge of plant taxonomy, plant breeding, plant pathology and plant genetics is helpful in the development of cultivation technology for medicinal and aromatic plants. Plant - chemistry (phytochemistry) has undergone significant development in recent years as a distinct discipline. It is concerned with the enormous variety of substances that are synthesized and accumulated by plants and the structural elucidation of these substances. Extraction, isolation, purification and characterization of phytochemicals from natural sources are important for advancement of medicine system. The knowledge of chemotaxonomy, biogenetic pathways for formation of medicinally active primary and secondary metabolites, plant tissue culture and other related fields is essential for complete understanding of Pharmacognosy. One should have the basic knowledge of biochemistry and chemical engineering is essential for development of collection, processing and storage technology of crude drugs.
- Pharmacognosy is important branch of pharmacy which is playing key role in new drug discovery and development by using natural products. Pharmacognosy has given many leads for new drug discovery and development.
- It is an important link between modern medicine systems (allopathy) and traditional system of medicine. It is part medicinal system which is affordable as well as accessible to common man. As part of integrative system of medicine, pharmacognosy can help to increase effectiveness of modern medicine system.
- It is acting as bridge between pharmacology, medicinal chemistry and pharmacotherapeutics and also pharmaceutics. It also bridges pharmaceutics with other pharmacy subjects.
- More than 60 percent of world population is still using natural product for their primary healthcare needs. Pharmacognosy can provide safe and effective drugs in combination with modern medicine system.
- Pharmacognosy includes knowledge about safe use of herbal drugs including toxicity, side effects, drug interaction thereby increasing effectiveness of modern medicine.
- Pharmacognosy is an important link between pharmacology and medicinal chemistry. As a result of rapid development of phytochemistry and pharmacological testing methods in recent years, new plant drugs are finding their way into medicine as purified phytochemicals, rather than in the form of traditional galenical preparations.
- Pharmacognosy is the base for development of novel medicines. Most of the compounds obtained from natural product serve as prototype or base for development of new drug which are more active and less toxic.
- By means of pharmacognosy, natural products can be dispensed, formulated and manufactured in dosage forms acceptable to modern system of medicine.
- There are vast number of plant and animal species which are not studied systematically.
- Development of pharmacognosy also leads to development of botany, taxonomy, plant biotechnology, plant genetics, plant pathology, pharmaceutics, pharmacology, phytochemistry and other branches of science.