Pharmacognosy Pdf Book
Rebecca Donnelly
Pharmacognosy is the study of crude drugs obtained from medicinal plants, animals, fungi, and other natural sources.[1] 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".[2]
As late as the beginning of the 20th century, the subject 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. Such branches of pharmacognosy are still of fundamental importance, particularly for botanical products (widely available as dietary supplements in the U.S. and Canada), quality control purposes, pharmacopoeial protocols and related health regulatory frameworks. At the same time, development in other areas of research has enormously expanded the subject. The advent of the 21st century brought a renaissance of pharmacognosy, and its conventional botanical approach has been broadened up to molecular and metabolomic levels.[5]
In addition to the previously mentioned definition, the American Society of Pharmacognosy defines pharmacognosy as "the study of natural product molecules (typically secondary metabolites) that are useful for their medicinal, ecological, gustatory, or other functional properties."[6] Similarly, the mission of the Pharmacognosy Institute at the University of Illinois at Chicago involves plant-based and plant-related health products for the benefit of human health.[7] Other definitions are more encompassing, drawing on a broad spectrum of biological subjects, including botany, ethnobotany, marine biology, microbiology, herbal medicine, chemistry, biotechnology, phytochemistry, pharmacology, pharmaceutics, clinical pharmacy, and pharmacy practice.
A typical protocol to isolate a pure chemical agent from natural origin is bioassay-guided fractionation, meaning step-by-step separation of extracted components based on differences in their physicochemical properties, and assessing the biological activity, followed by next round of separation and assaying. Typically, such work is initiated after a given crude drug formulation (typically prepared by solvent extraction of the natural material) is deemed "active" in a particular in vitro assay. If the end-goal of the work at hand is to identify which one(s) of the scores or hundreds of compounds are responsible for the observed in vitro activity, the path to that end is fairly straightforward:
In the past, in some countries in Asia and Africa, up to 80% of the population may rely on traditional medicine (including herbal medicine) for primary health care.[10] Native American cultures have also relied on traditional medicine such as ceremonial smoking of tobacco, potlatch ceremonies, and herbalism, to name a few, prior to European colonization.[11] Knowledge of traditional medicinal practices is disappearing in indigenous communities, particularly in the Amazon.[12][13][14]
With worldwide research into pharmacology as well as medicine, traditional medicines or ancient herbal medicines are often translated into modern remedies, such as the anti-malarial group of drugs called artemisinin isolated from Artemisia annua herb, a herb that was known in Chinese medicine to treat fever. However, it was found that its plant extracts had antimalarial activity, leading to the Nobel Prize winning discovery of artemisinin.[15][16]
Microscopic evaluation is essential for the initial identification of herbs, identifying small fragments of crude or powdered herbs, identifying adulterants (such as insects, animal feces, mold, fungi, etc.), and recognizing the plant by its characteristic tissue features. Techniques such as microscopic linear measurements, determination of leaf constants, and quantitative microscopy are also utilized in this evaluation. The determination of leaf constants includes stomatal number, stomatal index, vein islet number, vein termination number, and palisade ratio.[17]
Pharmacognosy is the study of medicines or crude drugs produced from natural sources such as plants, microbes, and animals. It includes analysis of their biological, chemical, biochemical, and physical properties.
Plants and organisms are used in a variety of ways in the production of conventional and alternative medicines. The beneficial active ingredient of the plant may be found anywhere in its physical structure, such as in the petal or stem of a flower.
The natural product might be inert in its usual physical form, so it may take a chemical reaction or modification to bring it into its active form. At times, the active ingredient is extracted directly from the plant, but on other occasions the active ingredient can be produced via synthesis by creating a compound that behaves similarly to the plant extract.
Plants are the source of many active ingredients used for medicinal purposes. Examples include salicylic acid and caffeine, among others. These natural compounds are often provide a great basis for the discovery of new drugs.
Humans have produced medicine from plants and other organisms for centuries, hence pharmacognosy being commonly considered the oldest brand of pharmacy. There is 5000-year-old evidence of medicine production on Sumerian clay from Nagpur, and around 12 ancient medicinal recipes have been found with plant ingredients such as poppy and mandrake, which is a Mediterranean plant in the nightshade family.
The production of drugs from plants is also referenced in many ancient texts. Through the ages, information has been discovered which refers to humans making medicines from garlic, mustard, cabbage, parsley, and mint.
No one country or nation dominated medicine production using plants and organisms; the practice was carried out globally. Ingredients would vary based on what was readily available to people in their environment.
The extraction of alkaloids from poppy and other plants contributed to the beginnings of modern medicine in the 19th century. From that point, other active ingredients were extracted from other plants to produce medications we have now.
Pharmacognosy is still a relevant science for the discovery of future medicines, with Japan and the USA very active in the field. Researchers are encouraged to be mindful of the ethical issues with using natural products as medicines.
For example, consideration has to be given to conservation of different plants to make sure that specific plants and organisms are not put at risk. Additionally, there must be high standards of quality control to ensure plants used for medicinal purposes are correctly identified and any drugs derived from them are of sufficient purity to be safe for use. It is suggested that periods of review are put in place to properly identify risks of long-term use of natural medicines and assess their toxicity. Medicines derived from natural sources are also often prescribed or administered by people outside of medical or pharmaceutical organizations, meaning advice given may not always be accurate or safe.
Deborah holds a B.Sc. degree in Chemistry from the University of Birmingham and a Postgraduate Diploma in Journalism qualification from Cardiff University. She enjoys writing about the latest innovations. Previously she has worked as an editor of scientific patent information, an education journalist and in communications for innovative healthcare, pharmaceutical and technology organisations. She also loves books and has run a book group for several years. Her enjoyment of fiction extends to writing her own stories for pleasure.
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The American Society of Pharmacognosy was founded in 1959 as an outgrowth of the Plant Science Seminar, which itself was established in 1923. The Society is international in scope and brings together men and women dedicated to the promotion, growth, and development not only of pharmacognosy but all aspects of those sciences related to and dealing in natural products. The Society currently has over 1,100 active and associate members. Approximately 40 percent of the active members of the Society reside outside of the U.S. and Canada, and represent more than 60 countries throughout the world.
Pharmacognosy is the study of natural product molecules (typically secondary metabolites) that are useful for their medicinal, ecological, gustatory, or other functional properties. The natural species that are the source of the compounds under study span all biological kingdoms, most notably marine invertebrates, plants, fungi, and bacteria. The field of pharmacognosy is ever-changing and is constantly being refreshed by input from new scientific fields and technologies as they are developed. This is one reason why studying pharmacognosy is a good choice for those who like to work at the interface of many different, but complementary, areas of science that relate to the natural world.
1. the study of the medicinal properties of natural products, for the purposes of drug discovery and understanding how dietary supplements work;
2. the development and use of analytical methods for quality control of natural products in the marketplace;
3. the study of the use of traditional remedies by native cultures;
4. the microscopic evaluation and species verification of medicinal or economically important natural products;
5. the use of natural products for specific agricultural purposes, such as natural pesticides or insect anti-feedants;
6. the study of the safety and functional properties of compounds found in novel foods or food ingredients and consumer products;
7. the cosmetic application of natural compounds or extracts; and
8. the study and manipulation of genetic biosynthetic pathways for the purpose of enhancing the production of natural compounds, or producing novel compounds.