Medicinal Plants Lecture 3 PDF

10/20/2022 Medicinal Plants Lecture 3 Dr. Samar Bassam Ergastic cell contents  Non–living substances present in the cell.  Can be identified in plants by microscopical examinat...

10/20/2022 Medicinal Plants Lecture 3 Dr. Samar Bassam Ergastic cell contents  Non–living substances present in the cell.  Can be identified in plants by microscopical examination or by chemical and physical tests.  Found in cytoplasm and vacuole. 1  10/20/2022 Ergastic cell contents Primary metabolites Secondary metabolites Essential for plant survival Not Essential for plant survival Organic compounds involved in They are organic compounds that are not directly growth, development, and involved in the normal growth, development or reproduction of the organism, thus, reproduction of an organism. often referred to as a central Have other functions, e.g defense, by products of metabolite metabolism Carbohydrates, proteins, lipids Alkaloids, volatile oils, tannins, flavonoids, … Unlike primary metabolites, absence of secondary metabolites does not result in immediate death Primary metabolites Carbohydrates Proteins Lipids 2  10/20/2022 Carbohydrates Definition: Compounds composed of C, H, O Organic compounds composed of carbon, hydrogen and oxygen, where the last two elements are present of the ratio 2:1 like that of their presence in water. Based on the number of sugar units, Carbohydrates as starch used as they are classified to: food or in cell structure as cellulose are considered primary 1- Monosaccharides (one sugar unit) metabolites. 2- Disaccharides (2 sugar units) Other carbohydrate derivatives 3- Oligosaccharides (3- 10 sugar units) such as gums and mucilage are 4- Polysaccharides (>10 sugar units). considered secondary They include starch and sugar. metabolites Role of Carbohydrates in plants: 1. Source of energy: Essential to perform normal functions as growth & metabolism. Energy can be stored in the form of starch (storage polysaccharide). Polysaccharides give a steady supply of energy while simpler sugars, monosaccharides and disaccharides, supply a quicker jolt (immediate energy). 2. Structural Function: For example, cellulose (structural polysaccharide) in plants cell wall. 3. Building blocks: The 5-carbon monosaccharide ribose is an important component of coenzymes (e.g. ATP, FAD and NAD) & the backbone of RNA. The related deoxyribose is a component of DNA. 3  10/20/2022 Starch - Is a polysaccharide formed of many glucose units. - Source of energy for the plant - Stored in the form of starch grains - The starch granule consists mainly of amylose and amylopectin Starch Amylose Amylopectin -Unbranched chain of glucose units -branched chain of glucose units - Soluble in water - Insoluble in water (swells) -gives blue colour with I2 -gives bluish black ppt with I2 ….commercial soluble starch ? General test for carbohydrates: Iodine test A suspension of starch gives a dark bluish black color Molisch's test A suspension of starch and alcoholic α-naphthol in a test tube ………… gives violet ring at the interface upon addition of concentrated H2SO4 on the wall of the test tube. 4  10/20/2022 Some Medicinal Uses of starch 1. Topically as dusting powder: alleviate itching & absorb moisture. 2. Antidote for iodine poisoning. 3. Lubricant for surgeons' gloves (modified starch). 4. Tablet disintegrant (expand when wet, causing the tablet to break apart in the digestive tract, releasing the active ingredients). 5. Suspending agent for barium meals (Radiography). 6. Nutrient and demulcent properties. The starches of pharmaceutical and commercial interest are: potato, maize, wheat and rice. - Each starch grain has a hilum which is a point of origin of starch deposition. - Starch is deposited in layers around hilum. - Hilum is located in the centre or in the periphery and the layers of starch are uniformly deposited around it forming striations. Starch Grain 5  10/20/2022 Other polysaccharides Mucilage and Gums A viscous sticky material, plays a A viscous secretion of some trees and protective role in thickening shrubs that hardens on drying but is membranes in plants. Forms soluble in water, and from which adhesive colloidal solution with water. products are made. Mucilage is used medicinally as They are classified as polysaccharides or demulcent (e.g. in cough), salts of polysaccharides emollient and bulk laxatives soothes and protects exposed or Used in pharmaceutical industry in irritated surfaces preparation of emulsions and suspensions Gives red color with Ruthenium red Pectin A purified carbohydrate obtained from the rind of citrus fruits (by extraction in acid medium). It is a source of dietary fiber. Pectin is a structural polysaccharide contained in the primary cell walls of terrestrial plants - used in food as a gelling agent - used in Pharmacy as - a suspending agent - in antidiarrheal formulations e.g. Kapect® 6  10/20/2022 Drugs derived from starch Hetastarch Dextrin Dextran (hydroxyethyl - starch) A product of partial degradation of starch Plasma expander Plasma expander Used in infant formulas for nutrition, In drug delivery.. oral disintegrating film Proteins They Can be classified into: 1. Structural proteins in cell membrane & cell wall. 2. Storage proteins mostly in seeds. 3. Enzymes. In plants, proteins are stored in the form of amorphous mass called aleurone grains, often consisting of a crystalloid and a globoid. The aleurone grain (protein body), is a specialized dry vacuole where storage proteins accumulate in a stable form in seeds. 7  10/20/2022 Identification tests for proteins: 1. Millon's reagent:  a red precipitate upon heating indicates the presence of protein in the sample. 2. Biuret test violet color Lipids Lipids: These are fats and fat-like substances are widely distributed in the plant, commonly in the seeds and fruits. They include: Fixed oils Fats Waxes Mainly, All are esters of long-chain fatty acids and alcohol Liquid Solids Solids Saponifiable Saponifiable Saponifiable unsaturated saturated saturated Olive oil Cocoa butter beeswax - All are non-volatile - Leave permanent stains on paper. - rancid during storage due to Oxidation by air (oxygen) - The oil globules are coloured red with Sudan III 8  10/20/2022 Thank you 9