Introduction to pharmacognosy

for B.Pharm 4th Sem

1. Introduction to Pharmacognosy and phytochemistry-i B.Pharm , 4 th semester

2. Brief idea about the subject Pharmacognosy is the study of drugs derived from natural sources. It forms an important part of pharmaceutical research and development . Pharmacognosy involves the identification, physicochemical characterization, cultivation, extraction, preparation, quality control, and biological assessment of drugs. A plant leaf, flower, root, animal or plant extract may be used to isolate the bioactive chemical . The term "Pharmacognosy" was coined by Anotheus Seydler in 1815 , a German botanist, from the two Greek words " pharmakon ", meaning drug or medicine , and "gnosis", meaning knowledge. According to the American Society of Pharmacognosy , the definition of pharmacognosy is "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". Crude drugs: Simple drugs exist in natural forms, obtained from plants, animals, marine and minerals in the raw forms used to treat certain diseases. Undergone no treatment other than collection and drying.

3. Pharmacognosy fields Ethnobotany / Ethnomedicine : The study of the traditional use of plants for medicinal purposes; Ethnopharmacology : The study of the pharmacological qualities of traditional medicinal substances; Phytotherapy : Medicinal use of plant extracts. Phytochemistry : Study of chemicals derived from plants (including the identification and study of structure analogue of new drug candidates derived from plants sources). Zoopharmacognosy : The process by which animals self-medicate, by selecting and using plants, soils and insects to treat and prevent disease. Marine pharmacognosy: The study of chemicals derived from marine organisms.

4. Importance of pharmacognosy Primary source of medicines (from ancient time to present day), for example– Digitoxin , Reserpine , Morphine, Ergotamine, etc. Identification of crude drugs, its biological source, part used, family, its collection and cultivation, preparation, adulteration, storage condition, medicinal uses. Isolation, analysis, chromatographic studies and characterization of phytoconstituents OR bioactive molecules Standardization (physical, chemical and biological (pharmacological evaluation) of crude drugs and herbal formulations Act as linking bridge between Pharmacology, pharmachemistry and pharmaceutics. Base or platform for drug development and research Documentation/preservation of crude drugs Study of biosynthetic pathways Production of secondary metabolites by PTC

5. Limitations A natural compound may be highly active but usually this is associated with high toxicity problem. Some compounds are found in natures that give beneficial pharmacological actions but their potencies are too low to be employed therapeutically. The yield of active natural products may be very low and thus the production cost of those drugs will be very high. The source of a natural drug may be very limited with respect to geography, season and climate, etc.

6. History of Pharmacognosy The Babylonians were aware of the Medicinal effects of a number of plants. Ancient Egyptians possessed a sound knowledge of human anatomy as well as a knowledge of the medicinal uses of many plants and animals. Papyrys Ebers - written in 1550 B.C. (16th century) & discovered in a tomb of a mummy contain more than 800 formula & 700 different drug. In India, the study of the drugs was started about 5000 years ago at the time of the Vedas. Ayrurvedic system (1200 B.C. Ago list with 127 plants.) Charaka -physician, 50 groups of 10 herbs each for illness.( Charak Samhita ); Sushruta -surgeon, 7 groups of 760 herbs based on properties of plants. ( Sushruta Samhita ) Hippocrates (460 - 370 B.C.) deals with anatomy and physiology in many of his treatises.“Father of Medicine”.

7. Egyptians ( Ebers papyrus, 1550 BC)

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

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

10. Aristotle (384 - 322 B.C.), the great philosopher wrote much about the animal kingdom and his writings were placed on scientific footing free from all superstitions. Theophrastus (370-287 B.C.) wrote about plants and described medicinal uses of plants. Dioscorides a Greek physician of the 1st Century A.D. was the writer of the first Materia Medica (40- 80 A.D.) Here he described 600 medicinal plants, including Belladona , Colchicum, Opium, Hyoscyamus , etc. C.A. Seydler , German scientist, a medical student at Halle, Germany in 1815; wrote his doctoral thesis titled Analectica Pharmacognostica . Carolus Linnaeus (1707 – 1778) classified the plant & introduced the system of naming the plant known as binomial system.

11. Galen (131 -200 A.D.) the first Pharmacist , who described the method of preparing drugs of vegetable and animal origin and laid down many formulas contained in a treatise(thesis) of 20 volumes. Plant Classification was developed by Benthan & Hooker (1862 – 1863), A.W. Eichler (1883), Engler & Prandtl (1887 – 1898) In 1865, G. Mendel’s important observation on plant hybrids

12. Scope of Pharmacognosy 1. ISOLATION OF PHYTOCHEMICALS Glycosides from digitalis leaves, Alkaloids from the plants of Belladonna, Hyocyamus , Rauwlofia Morphine and other alkaloids from the plant opium 2. STRUCTURE ACTIVITY RELATIONSHIP Tubocurarine and Toxiferine from curare plant have muscle relaxant properties because of quaternary ammonium groups. The hypotensive and tranquillizing actions of reserpine are due to the trimethoxy benzoic acid 3. DRUGS OBTAINED BY PARTIAL SYNTHESIS OF NATURAL PRODUCTS Preparation of Steroid hormones from diosgenin by acetolysis and oxidation and further preparation of cortisone by microbial reactions.

13. 4. NATURAL PRODUCTS AS MODELS FOR SYNTHESIS OF NEW DRUGS Morphine is the model of a large group of potent drugs Cocaine for local anaesthetics Atropine for certain spasmolytics 5. DRUGS OF DIRECT THERAPEUTIC USES Antibiotics, steroids, ergot alkaloids, vincristine , etc 6. BIOSYNTHETIC PATHWAYS INVESTIGATION Biosynthetic pathways of primary and secondary metabolites. 7.CULTIVATION AND COLLECTION OF MEDICINAL PLANTS Clove, cinchona , cinnamon, senna , opium, etc. 8. PREPARATION OF HERBAL FORMULATIONS Churnas , asvas , aristas , leha , etc.

14. Development of Pharmacognosy Modern Pharmacognosy occurred during 1934 - 1960. This development was mainly due to some events like: Discovery of Penicillin in 1928 Isolation of Resperine 1952 Anticancer properties of Vinca rosea Discovery of Dioscorea was utilized to prepare semisynthetic steroidal hormones.

15. Development of Pharmacognosy Pharmacognosy as an applied science. It played a crucial role in the development of different disciplines of science. Pharmacognosy is an imp link between Pharmacology and Medicinal Chemistry Step by step processes in biosynthesis of Primary & Secondary metabolites were presented before the world. Invention of microscopy and different chemical test reagents.

16. Development of Pharmacognosy Knowledge of Plant taxonomy Plant breeding Plant pathology Plant genetics Are helpful in the development of cultivation technology for medicinal and aromatic plants.