SOURCES OF DRUGS Zubair Latif SOURCES OF DRUGS • Natural Source • Synthetic Source • Semi-Synthetic Source • Biosynthetic Source 1. NATURAL SOURCE • This source is used from earliest time and still being used because of economical and easy availability of drugs. Most important natural sources of drugs are; • Plants • Animals • Microorganisms • Minerals Plants • Plants have been used for centuries for treatment of disease. Used in home preparations. • The traditional system of Tibb, Ayurveda, and Unani system of medicine are based on the use of plants and other natural substances. • Biological activity of plants are due to presence of certain chemicals in it. These are isolated with different techniques. • Barks, fruits, leaves, seeds roots are being used. In some cases entire plant may be used. Parts of plants used as source of drugs Part of Name of Plant Active Uses Plant Constituent Bark Cinchona Quinine Antimalarial Flower buds Clove Eugenol Local Anesthetic fruit Anise Anethole Carminative Rhizomes Ginger Gingerol Carminative seeds Nuxvomica Strychnine CNS Stimulant Whole Plant Ephedra Ephedrine Sympathomimetic Nature of chemicals obtained from plants • Alkaloids • Glycosides • Oils • Resins • Tannins • Gums • Organic Acids Alkaloids • Complex organic molecules Bitter in taste containing nitrogenous compounds having one or more heterocyclic ring. • They are solid colorless crystalline compounds containing carbon, hydrogen, oxygen and nitrogen. • Alkaline in reaction when combine with acid forms crystalline salt without water. These salts are used in preference to pure alkaloid. • Soluble in alcohol sparingly soluble in water. Salts are soluble in water. • Their name is mostly end with -ine EXAMPLES: Solid Alkaloids: Atropine, Morphine, Quinine, Strychnine Liquid Alkaloids: Arecoline, Nicotine, Lobeline. Glycoside • These are molecules in which a sugar is bound to a non- carbohydrate moiety, These are complex organic compounds containing carbon, hydrogen, and oxygen having sugars attached to a non sugar part by ether linkage. • First glycoside isolated from bitter almonds. • Neutral in reaction and don’t combine with acid to form salts. • Soluble in alcohol, upon acid hydrolysis give rise to a non sugar part (aglycone) and one or more sugar parts (Glycone). When sugar formed is glucose (Dextrose) the glycoside is referred as glucoside thus producing galactose called galactoside. • Name ends with in. EXAMPLES: Digitoxin and Digoxin from digitalis plant. Digitalis purpurea Saponins • These are plant glycosides (aglycone linked to sugar) having property of frothing when shaken in water. • The best known sources of saponins are peas, soybeans, and some herbs with names indicating foaming properties such as soapwort, saoproot. • Commercial saponins are extracted mainly from Yucca schidigera and Quillaja saponaria. EXAMPLE: Digitonin, Senegin Oils • Substance obtained from plants, animals, or mineral sources. They are of three type. • Volatile Oils • Fixed oils • Mineral oils Volatile oils • These are called essential, aromatic, flavoring oils. • Obtained from plants that are volatilized by heat. Contains alcohol, aldehydes, ketone, esters, phenols and terpenes. • Secreted in particular cell in the plant from flower, leaves, and fruits give aroma to plant. • They are colorless liquid and crystalline solids. • Evaporate on exposure at ordinary temperature and don’t leave greasy spot. • Obtained mainly from distillation without being decomposed. • Less soluble in water highly soluble in alcohol and ether. Perfumes. • Don’t form soap with alkalis. EXAMPLES • LIQUID: Eucalyptus oil, clove oil peppermint oil. • SOLID: Camphor, Menthol and Thymol Fixed oils • These are esters of glycerol with long chain fatty acids termed as glycerides. • Liquid at room temperature. • Leave permanent greasy spot, non volatile in nature. • Insoluble in water, sparingly soluble in alcohol freely soluble in ether. • From soap with alkalis. • Turn rancid on heating. • EXAMPLES: Olive oil, Castor oil, Linseed oil Mineral oil A mineral oil is any of various colorless, odorless, light mixtures of alkanes in the C15 to C40 range from a non- vegetable (mineral) source, particularly a distillate of petroleum. Most often, mineral oil is a liquid by-product of the distillation of petroleum to produce gasoline and other petroleum-based products from crude oil. Resins • These are solid substances produced by oxidation and polymerization of volatile oils. • These are secretions of plant tissues. They are formed in plants in specialized passage or tube called resin duct and often collected by incision on particular area of plant. • Amorphous and brittle solid. Insoluble in water and soluble in organic solvents. • EXAMPLE: Jalap, Podophyllum. Tannins • These are the phenolic compounds having astringent action on the mucous membrane. • Non nitrogenous compounds, soluble in water. • They are bitter in taste. • They are of two types persimmon fruit. Pyrogallol Tannins Pyrocatechol Tannins Organic Acids • Several organic acids are present in plants includes Citric Acid, Tartaric Acid, Benzoic Acid, and Salicylic Acid. Animals • It is also an important source of drugs but much expensive. • Important products obtained from animals are; • Antisera: (Antitetanus serum, Canine distamper serum, HS serum) • Hormones: (Insuline, eCG, Thyroxine) • Vitamins: (Cod-liver oil) • Enzymes: (Trypsin, Chymotrypsin, Pepsin, fibrinolydin) • Blood and blood components: Whole blood, Plasma, Platelets etc. Microorganisms • They are the major source of many drugs including; • Antibiotics: (Penicillin, Cephalosporin, tetracycline) • Vaccines: (Antirabies vaccine, Canine distemper vaccine, Hepatitis Virus vaccine) • Vitamins: (B-complex by yeast) Minerals • These are simple elements or their salts and are important source of drugs. • They are isolated from mines by processing ore with smelting. 2. SYNTHETIC SOURCE • These drugs are prepared in the Laboratory from chemicals. Most drugs used today are of synthetic in origin. • These drugs are chemically pure and can be manufactured in bulk to maintain the supply line. • Examples are diethyl ether, Sulphonamide, Aspirin, procaine and Diphenhydramine. 3. SEMI-SYNTHETIC SOURCE • These drugs are synthesized in Laboratory by utilizing a naturally occurring complex chemical as a starting material. • These drugs are neither pure natural nor pure synthetic. Natural Penicillin • Now a days this source of drug manufacturing is extensively used because of economics. • EXAMPLES • Antibiotics like Ampicillin, Amoxicillin and Cephalosporins are prepared semi-synthetically. Ampicillin 4. Bio-SYNTHETIC SOURCE • This involves the recent introduction of recombinant DNA technology. This technology is now being used for large scale production of some complex drugs. • EXAMPLES • Biosynthesis of human Insulin, Human erythropoietin, Bovine somatotropin hormones.