Chemical nature of Crude Drugs

Examples of different types of Glycosides Examples of Tannins

Alkaloids Tests for evaluation of alkaloids Types of alkaloids On completion of this period, you would be able to know Objectives

Alkaloids are basic Nitrogenous compounds generally Nitrogen is present in a heterocyclic ring present in plants possessing marked physiological action when given internally Alkaloids in high doses are poisonous Alkaloids

Most of the alkaloids are colourless All the alkaloids are bitter in taste Optically active Occur in the form of salts with citric, oxalic, lactic or tartaric acids Their l-isomers are pharmacologically more active Alkaloids are insoluble in water Soluble in organic non-polar solvents like Chloroform Benzene, ether etc.,

Alkaloids Alkaloids may present in various plant organs Examples: Seeds Nux-vomicaSpinal stimulant Leaves Datura Antisposmodic Roots Rauwolfia Antihypertensive Barks Cinchona Antimalarial Stems Ephedra Antiasthmatic Exudates Opium Narcotic analgesic

1.Mayer’ Reagent Cream or Grayish Precipitate 2.Dragendorrf’s reagent Brown / Reddish brown precipitate 3.Wagner’s reagent Brown/Reddish brown precipitate 4.Hager’s reagent Yellow precipitate 5.Phosphotungstic acid Specific precipitate 6.Tannic acid Specific precipitate Identification tests of Alkaloids

Reactions of Alkaloids Brucine gives yellow colour With Nitric acid Morphine gives violet colour with sulphomolybdic acid Caffeine gives specific colour with potassium chlorate

Many classification systems are possible for alkaloids Due to variety of sources Basic chemical structure, Pharmacological action Classification of Alkaloids

1. Tropane Atropine Datura Cocaine Coca 2. Quinoline Quinine Cinchona 3. Isoquinoline Papaverine Opium Emetine Ipecac 4. Indole Strychnine Nux-vomica Reserpine Rauwolfia Vasicine Vasaka

Classification of Alkaloids 5. Purine Caffeine Tea 6. Pyrrole & Pyrrolidine Nicotine Tobacco 7. Pyridine & Piperidine Ricinine Castor 8.Phenanthrene Morphine Opium 9. Imidazole Pilocarpine Pilocarpus 10.Steroidal Connesine Kurchi 11. Alkaloidal amines Ephedrine Ephedra

Summary In this class we learnt about Alkaloids Examples of alkaloids Tests for determination of alkaloids

Quiz 1. Potassium Mercuric iodide solution is known as a)Dragendorff’s regent b)Hager’s reagent c)Mayer’s reagent d)None of the above

Quiz 2. Vasicine alkaloid contains a)Phenanthrene ring b)Pyrrolidine ring c)Quinazoline group d)Isoquinoline ring

Frequently Asked Questions 1.Define the term Alkaloid and Classify alkaloids with examples?