Medicinal Plants PHG111 Lecture 4 Fall 2024 PDF

Medicinal Plants PHG111 Pharmacognosy I PG 101 Prof. Dr. Mahitab Helmi Dr. Ibrahim Ezzeldin Faculty of Pharmacy  Lecture 4 Chemistry of Crude Drugs Interactive teaching methods and activities: https://www.youtube.com/watch?v=BjXaIkBQCdo By the end of this lectur...

Medicinal Plants PHG111 Pharmacognosy I PG 101 Prof. Dr. Mahitab Helmi Dr. Ibrahim Ezzeldin Faculty of Pharmacy  Lecture 4 Chemistry of Crude Drugs Interactive teaching methods and activities: https://www.youtube.com/watch?v=BjXaIkBQCdo By the end of this lecture students must be able to Differentiate between 1ry & 2ry metabolites Classify 1ry metabolites, its chemical nature, tests & uses Classify 2ry metabolites, its chemical nature, tests & uses  Chemistry of Crude Drugs Food Storage Products By-Products of Metabolism (Primary Metabolites) (Secondary Metabolites) -Found in all plants -Have specific functions -Have nutritional value - Are of pharmacognostical -Can be used in pharmacy importance a- starch a– Gums & Mucilages b- Amino acids & b- Tannins Proteins c- Volatile Oils c- Fixed oils & Fats d- Alkaloids e- Glycosides  I. Food storage products A- Starch As granules in all storage organs e.g. roots rhizomes and seeds Starch is a polysaccharides of high molecular weight ( polymer of glucose and formed during photosynthesis) Special chemical test: It gives blue color with iodine  Uses of starch 1. In tablet formulation: diluents, binder. 2. Skin emollient 3. Dusting powder for cosmetic preparation 4. Antidote of iodine poisoning Some starches of commercial importance Food storage products (cont.) B- Proteins As aleurone grains in seeds They are complex nitrogenous organic substances of high molecular weight, composed of a large number of amino acids It is composed from ground mass, globoids and crystalloid Special chemical test Globoid Amorphous protein 1-It gives red color with Millon’s reagent. Crystalloid protein 2- It gives yellow color with picric acid Food storage products (cont.) C- Fixed oil and fats Esters of long chain fatty acids of high molecular weight Found in seeds e.g. Nutmeg Reserve fats occur as crystalline masses or as oil drops. Special chemical test : It gives red color with Sudan III Uses of Fixed oils and Fats: 1- Nutritive use 2- Pharmaceutically as solvents in intramuscular injections 3- Preparation of soaps, plasters 4- Laxatives, demulcents and emolients.  II-By-Products of Metabolism Chemical Constituents These are chemical substances synthesized by the plant and are present in the crude drugs 3.Have 2. Possess pharmacological 1. Extracted different Action & from plants Therapeutic activity physical and 4. Economic by different chemical importance methods properties.  1-Gums, Mucilages Gums: A viscous secretion of some trees that hardens on drying , soluble in water, and from which adhesives and other products are made. Polysaccharide or salt of polysaccharides e.g. gum acacia Mucilages: Polysaccharide complex, insoluble in alcohol, forming viscous colloid in water Test: Ruthenium red (senna) or methylene blue (foenugreek)  2- Tannins Water soluble polyphenolic compounds, which may have high molecular weight, have a very wide distribution in the plant kingdom. A- Hydrolysable tannins B- Condensed tannins (pyrogallol tannins): - (catechol tannins)  FeCl3 -------bluish black color  FeCl3 -------green color  It gives no precipitate with  It gives precipitate with bromine water bromine water  On heating with hydrochloric or  It decomposes into red sulfuric acids, yields gallic or insoluble phlobaphene ellagic acids, producing red color to the drugs carbohydrate and phenolic acids.  e.g. Cinnamon, tea  e.g. Cloves  Uses of tannins 1. Astringent in GIT (treatment of diarrhea) 2-It has antioxidant effect ( anti-cancer , anti- ulcer…) 3-Hemostatic in skin cuts 4- Manufacture of dyes and ink 5-Tanning of leather  3- Volatile oils (essential or ethereal oils) Nature: Odoriferous principles in plants. Volatile mixture of hydrocarbon & oxygenated hydrocarbon. Occurrence: They are secreted with several secretory structures, i.e. Cells, glands, ducts, hairs Detection: It gives red color with sudan III Uses: Volatile oils are mostly used as flavoring agents, in perfumery (lavender oil, oil of rose ) , spices (clove), carminative (oil of Anise) while some volatile oils have therapeutic uses (urinary tract antiseptic, anti-rheumatic)  Differences between Volatile oil & Fixed oil Property Volatile oil Fixed oil 1. Chemical composition Different types of Glyceryl esters of fatty hydrocarbons & oxygenated acids compounds 2. Occurrence In odoriferous drugs in cell , In seed and fruit as cavity ,glandular hair. reserve food material. 3. Detection Red color with Sudan III. Red color with Sudan III. 4. Stain on filter paper No persistent stain Persistent and greasy stain 5.Volatilization at Volatile Non-volatile Ordinary temperature 6.Action of air and light Resinification Rancidity during storage 7- Soap formation Negative Positive References: Author Date Title Publisher ISBN Michael Heinrich, 2012 Fundamentals of Elsevier Health 0702052310, Joanne Barnes, Simon Pharmacognosy and Sciences 9780702052316 Gibbons, Elizabeth M. Phytotherapy Williamson. Biren Shah, Avinash 2012 Textbook of Elsevier Health 8131232603, Seth Pharmacognosy and Sciences 9788131232606 Phytochemistry William Charles 2009 Trease’s Elsevier Health 0702041890, Pharmacognosy, 16th Sciences 9780702041891 Evans edition Compare between each of the following: 1- Starch & protein ( chemical composition, occurrence, tests) 2-Hydrolyzable ( pyrogallol) tannins & Condensed (catechol) tannins( chemical composition, occurrence, tests) Faculty of Pharmacy