BP504T — PHARMACOGNOSY AND PHYTOCHEMISTRY–II UNIT – II -Part 1
Subject: Pharmacognosy and Phytochemistry II
BP504T — PHARMACOGNOSY AND PHYTOCHEMISTRY–II UNIT – II Secondary Metabolites: General Introduction, Composition, Chemistry, Chemical Classes, Bio-sources, Therapeutic Uses & Commercial Applications SYLLABUS COVERAGE — COMPLETE STUDENT NOTES S. No. Topic / Chemical Class Official Drugs / Examples Covered 1 Alkaloids Vinca, Rauwolfia, Belladonna, Opium 2 Phenylpropanoids & Flavonoids Lignans, Tea, Ruta 3 Steroids, Cardiac Glycosides & Triterpenoids Liquorice, Dioscorea, Digitalis 4 Volatile Oils Mentha, Clove, Cinnamon, Fennel, Coriander 5 Tannins Catechu, Pterocarpus 6 Resins Benzoin, Guggul, Ginger, Asafoetida, Myrrh, Colophony 7 Glycosides Senna, Aloe, Bitter Almond 8 Iridoids, Other Terpenoids & Naphthaquinones Gentian, Artemisia, Taxus, Carotenoids HOW TO USE THESE NOTES Each drug is presented in the same exam-ready format : Synonym → Biological Source → Family → Geographical Source → Macroscopy/Microscopy → Chemical Constituents → Chemical Tests → Therapeutic Uses Study Tip For every crude drug, remember these 7 core headings : 1. Source → 2. Family → 3. Distribution → 4. Identification → 5. Constituents → 6. Chemical Test → 7. Uses 1. ALKALOIDS 1.1 GENERAL INTRODUCTION Alkaloids are basic, nitrogen-containing organic compounds obtained from plants, animals and micro-organisms, having marked physiological/pharmacological action. They are one of the most important classes of plant secondary metabolites . The term ' alkaloid ' (= alkali-like) was coined by W. Meissner in 1819. Basicity is due to the availability of a lone pair of electrons on the nitrogen atom. Additional Key Point Alkaloids are generally characterized by: Nitrogen-containing compound → Basic nature → Usually bitter taste → Marked physiological action FORMS OF NITROGEN IN ALKALOIDS Form Example Primary amine Mescaline Secondary amine Ephedrine Tertiary amine Atropine Quaternary amine Tubocurarine chloride Quick Memory Line Primary → Mescaline Secondary → Ephedrine Tertiary → Atropine Quaternary → Tubocurarine chloride GENERAL PROPERTIES OF ALKALOIDS Mostly colourless, crystalline, non-volatile, bitter-tasting solids ( nicotine is a brown liquid — an exception). Levo (l-) isomers are usually more pharmacologically active than dextro forms. Colour exceptions: Betanidine – red; Sanguinarine – copper red; Berberine & Tylophorine – yellow. Liquid alkaloids: Sparteine, Conine, Nicotine . Optically inactive alkaloids: Papaverine, Atropine . Property Examples Liquid alkaloids Sparteine, Conine, Nicotine Red Betanidine Copper-red Sanguinarine Yellow Berberine, Tylophorine Optically inactive Papaverine, Atropine CLASSIFICATION OF ALKALOIDS — BY NUCLEUS Type Basic Nucleus Example / Source Plants Pyridine–Piperidine Pyridine / Piperidine ring Tobacco, Areca, Lobelia Tropane N-methyl bicyclic ring Belladonna, Datura, Hyoscyamus, Coca Quinoline Quinoline ring Cinchona, Camptotheca Isoquinoline Isoquinoline ring Opium, Ipecac, Curare Indole Indole ring Ergot, Nux-vomica, Rauwolfia, Vinca Imidazole Imidazole ring Pilocarpus Steroidal Steroid nucleus Veratrum, Kurchi, Ashwagandha Alkaloidal amine Amine side-chain (no ring N) Ephedra, Colchicum Purine Purine ring Tea, Coffee, Kola, Cocoa Glycoalkaloid Steroid + sugar Solanum Quinazoline Quinazoline ring Vasaka Terpenoid Terpene skeleton Aconite Pyrazoline Pyrazole ring Pepper TYPES OF ALKALOIDS — BY BIOGENETIC ORIGIN Type Description Examples True alkaloid N derived from amino acid, present in a heterocyclic ring; bitter; forms water-soluble salts Atropine, Morphine, Nicotine Proto alkaloid N from amino acid but NOT part of the heterocyclic ring Hordenine, Mescaline, Yohimbine Pseudoalkaloid Carbon skeleton NOT derived from amino acid Coniine, Capsaicin, Ephedrine, Caffeine, Theobromine Polyamine alkaloid Derived from spermidine/spermine — Peptide/cyclopeptide alkaloid Peptide-derived Sativanine-N, Sativanine-O Easy Concept True alkaloid → N is in heterocyclic ring Protoalkaloid → N is NOT in heterocyclic ring Pseudoalkaloid → carbon skeleton is NOT derived from amino acid CHEMICAL (PRECIPITATION) TESTS FOR ALKALOIDS Reagent / Test Composition Observation Dragendorff's test Potassium bismuth iodide Orangish-red colour Mayer's test Potassium mercuric iodide Creamy-white precipitate Hager's test Saturated aq. picric acid Crystalline yellow precipitate Wagner's test Dilute iodine solution Reddish-brown precipitate Tannic acid test Tannic acid solution Buff-coloured precipitate Ammonia reineckate test Acidified ammonium reineckate Pi
Each drug is presented in the same exam-ready format:
Synonym → Biological Source → Family → Geographical Source → Macroscopy/Microscopy → Chemical Constituents → Chemical Tests → Therapeutic Uses
Study Tip
For every crude drug, remember these 7 core headings: 1. Source → 2. Family → 3. Distribution → 4. Identification → 5. Constituents → 6. Chemical Test → 7. Uses
1. ALKALOIDS
1.1 GENERAL INTRODUCTION
Alkaloids are basic, nitrogen-containing organic compounds obtained from plants, animals and micro-organisms, having marked physiological/pharmacological action.
They are one of the most important classes of plant secondary metabolites.
The term 'alkaloid' (= alkali-like) was coined by W. Meissner in 1819.
Basicity is due to the availability of a lone pair of electrons on the nitrogen atom.
Additional Key Point
Alkaloids are generally characterized by: Nitrogen-containing compound → Basic nature → Usually bitter taste → Marked physiological action
True alkaloid → N is in heterocyclic ring Protoalkaloid → N is NOT in heterocyclic ring Pseudoalkaloid → carbon skeleton is NOT derived from amino acid
Synonyms
