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PHG 322 PHARMACOGONSY II LECTURE 1 PRESENTED BY ASSISTANT PROF. DR. EBTESAM ALSHEDDI بسم الله الرحمن الرحيم.

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Presentation on theme: "PHG 322 PHARMACOGONSY II LECTURE 1 PRESENTED BY ASSISTANT PROF. DR. EBTESAM ALSHEDDI بسم الله الرحمن الرحيم."— Presentation transcript:

1 PHG 322 PHARMACOGONSY II LECTURE 1 PRESENTED BY ASSISTANT PROF. DR. EBTESAM ALSHEDDI بسم الله الرحمن الرحيم

2 Office: second flour # 84 Site: faculty.ksu.edu.sa/10252

3 3 Topics to be covered: (cont.) 1) Plants containing Alkaloids (botanical and chemical characters):  Introduction  Phenylalkylamine, Tropolone and Imidazole alkaloids  Pyridine and piperidine alkaloids  Tropane alkaloids  Quinoline and isoquinoline alkaloids  Opium alkaloids  Indole alkaloids  Carboline, purine, steroidal and terpenoidal alkaloids

4 4 Topics to be covered: 2) Marine derived drugs:  Biomedical potential of marine natural products  Microalgae as a drug source  Biologically active substances from marine sponges

5 5 Topics to be covered: 3) Plants containing Glycosides (botanical and chemical characters):  Introduction  Phenolic, cyanogenic and thioglycosides  Coumarins, flavonoidal glycosides and related compounds  Anthracene derivatives  Cardiac glycosides  Saponins

6 4)Toxicological Pharmacognosy:  Poisonous plants  Plants as drugs of abuse  Hepatotoxic plants  Toxic mushrooms 3)Herb-drug interactions Topics to be covered: 6

7 7  Important Book/Thesis: No.Book/Thesis Editor or Author Date of pub. Name of Publisher 1 Pharmacognosy 16 th edition Trease and Evans 2009 Saunders London, New York, … 2 النباتات السامة في المملكة العربية السعودية عبد الله بن أحمد الأمير 2000 جامعة الملك سعود كلية العلوم قسم النبات والأحياء الدقيقة 3 Bioactive Marine Natural Products Bhakuni and Rawat 2005 Anamaya Publishers, New Delhi, India

8 8 Marks Assessment task Dr. RababbDr. Ebtesam -18 First ½ of semester (Exam + Activity/Quiz) 18-Second ½ of semester 24Practical 20 Final Exam 100Total  The assessment tasks during the semester:

9 Alkaloids Definition Alkaloids, which mean alkali-like substances, are basic nitrogenous compounds of plant or animal origin and generally possessing a marked physiological action on man or animals. The nitrogen is usually contained in a heterocyclic ring system.The nitrogen is usually contained in a heterocyclic ring system. Deviation from Definition 1)Some alkaloids are not basic e.g. Colchicine, Piperine, 2)Few alkaloids contain nitrogen in a non-ring system e.g. Ephedrine, Colchicine. Mescaline 3) Plant origin: Some alkaloids are derived from bacteria, fungi, insects, frogs, animals.

10 1) Protective function against insects or herbivores 2) They are end products (detoxification) 3) Source for energy and reserve of nitrogen Function of alkaloids in plants

11 DISTRIBUTION IN PLANT: All Parts e.g. Datura. Barks e.g. Cinchona Seeds e.g. Nux vomica Roots e.g. Aconite Fruits e.g. Black pepper Leaves e.g. Tobacco Latex e.g. Opium

12  Genus name e.g. Atropine from Atropa  Species name e.g. Cocaine from Coca  Common name e.g. Ergotamine from Ergot  Physiological activity e.g. Emetine (emetic)  Discoverer e.g. Pelletierine from Pelletier Nomenclature  Alkaloids terminate with the suffix: (ine)  Their names may be derived from: 12

13 Prefixes and suffixes These are, usually, added to the name of the parent alkaloid and are used to designate related alkaloids, generally present in the same plant. I. Prefixes Examples are: 1)Nor-: designates N-demethylation or N-demethoxylation e.g. Nornicotine 2)Apo-: designates dehydration e.g. Apomorphine 3)Iso-, Pseudo-, Neo- and Epi- indicate different types of isomers 13

14 II. Suffixes 1) –dine: designates isomerism as in case of the Cinchona alkaloids quinine (l) & quinidine (d) cinchonidine (l) & cinchonine (d) cinchonidine (l) & cinchonine (d) 2) –ine: indicates, in case of ergot alkaloids, a lower pharmacological activity e.g. ergotaminine is less potent than ergotamine 14

15 volatile e.g. pilocarpine and hyoscine  Some are liquids Physical properties: 1) Condition:  Most alkaloids are crystalline solids e.g. nicotine and coniine non-volatile  Some are coloured: 2) Colour: - colchicine & berberine yellow  Most alkaloids colourless - canadine orange 15

16 3) Solubility: 16  Solubility of alkaloids & their salts is important because: a) They are often administered in solution b) Differences in solubility between alkaloids & their salts is used for: salts is used for: - isolation of alkaloids - purification from non-alkaloidal substances

17 Solvent Alkaloidal bases Alkaloidal salts Alcohol Organicsolvents H2OH2OH2OH2O Soluble Soluble Soluble Soluble Insoluble Insoluble - theobromine & theophylline theophylline → benzene (insol.) except: - morphine & psychotrine → insol. in ether → insol. in ether except: - caffeine - ephedrine - codeine - colchicine - pilocarpine - quat. ammonium bases quinine sulphate → insoluble in H 2 O except: except: - lobeline hydrochloride → CHCl 3 (soluble) 17

18 18 Optically active isomers may show different physiological activities. l-ephedrine is 3.5 times more active than d-ephedrine. l-ergotamine is 3-4 times more active than d- ergotamine. d- Tubocurarine is more active than the corresponding l- form. Quinine (l-form) is antimalarial and its d- isomer quinidine is antiarrythmic. The racemic (optically inactive) dl-atropine is physiologically active. 4) Optical activity:  Many alkaloids are optically active due to ? → presence of one or more asymmetric carbon atom(s)

19 19 coniine Chemical properties:  Alkaloids contain: C, H, N  Most of them contain oxygen  Few alkaloids are oxygen free nicotine

20 CHEMICAL PROPERTIES: I- Nitrogen: Primary amines R-NH 2 e.g. Norephedrine Secondary amines R 2 -NH e.g. Ephedrine Tertiary amines R 3 -N e.g. Atropine Quaternary ammonium salts R 4 -N e.g d-Tubocurarine II- Basicity: R 2 -NH > R-NH 2 > R 3 -N Saturated hexacyclic amines is more basic than aromatic amines.

21 1) Nitrogen in alkaloids Number of Number of nitrogen atoms Type of amino Type of amino group group Basicity 1) Number of nitrogen atoms: Usually one N atom Usually one N atom Some contain more than one Some contain more than one → up to 5 N atoms e.g. nicotine → two ergotamine → five 21

22 2) Type of amino group: N in alkaloids → in form of amine N in alkaloids → in form of amine Primary amino group Secondary amino group Tertiary amino group Quaternary ammonium ion Norpseudo- ephedrine e.g. Ephedrine Nicotine Tubocurarine

23 → form salts with acids without liberation of H 2 O 3) Basicity:  A lone pair of electrons on N atom → basic character → alkaloids resemble NH 3 in chemical characters Alkaloid + H + Cl - Alkaloid hydrochloride ][ 23 Present as: ][

24 Factors influencing the degree of basicity: Structure of the molecule e.g. degree of unsaturation of heterocyclic ring of heterocyclic ring Pyridine Piperidine Piperidine alkaloids → more basic than pyridine alkaloids unsaturation decreases basicity Presence & position of other substituents & fuctional groups Electron releasing groups Electron withdrawing gps increase basicity decrease basicity e.g. alkyl group e.g. carbonyl group 24

25 Morphine → Alkaloids may be: → electron availability on nitrogen atom decreases nitrogen atom decreases e.g. phenolic alkaloids e.g. alkaloids containing e.g. alkaloids containing carboxylic group carboxylic group  Neutral (not basic)  Amphoteric → due to the presence of acidic group(s) Narceine 25 Ricinine

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