Natural drugs Drugs that originate in animals, plants, or microorganisms.

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1 atural drugs Drugs that originate in animals, plants, or microorganisms. Pharmacognosy ( ) An applied science that deals with the biologic, biochemical, and economic features of natural drugs and their constituents. Classification of natural drugs 1. Alkaloids ( ): Alkali-like natural compounds 2. Glycosides ( ): Compounds that yield one or more sugars among the products of hydrolysis. 3. Steroids ( 類 ): Compounds that contain cyclopentanoperhydrophenantrene nucleus. 4. Antibiotics ( ): A chemical substance that produced by a microorganism that has the capacity, in low concentration, to inhibit selectively or even to destroy bacteria and other microorganism through an anti-metabolic mechanism. 5. Volatile oils ( ): dorous constituents. Alkaloids ( ) -rganic nitrogenous compounds with a limited distribution in nature. -Most possess basic properties and mark physiological activity. -The nitrogen may exist as a primary amine (R 2 ), as a secondary amine (R 2 ), as a tertiary amine (R 3 ), or as a quaternary amine (R 4 + X - ). The names of the alkaloids are obtained in various ways: 1. From the generic name of the plant yielding them (hydrstine, atropine). 2. From the specific name of the plant yielding them (cocaine, belladonine). 3. From the common name of the plant yielding them (ergotamine). 4. From their physiological activity (emetine, morphine). 5. From the discoverer (pelletierine). Extraction and isolation

2 Function of alkaloids 1. Protection 2. End products of detoxification 3. Regulatory growth factors Pharmacological action of alkaloid 1. Analgesics and narcotics (morphine) 2. Central stimulants (strychnine) 3. Mydriatics (atropine) 4. Miotics (physostigmine, pilocarpine) 5. ypertension (ephedrine) 6. ypotension (reserpine) Classification of alkaloids based on ring structure or nucleus: piperridine pyridine quinoline isoquinoline tropane indole imidazole purine Classification of alkaloids based on biosynthetic precursor: C C C 2 phenylalanine tyrosine 2 2 tryptophan C C C ornithine lysine histidine Tropane Alkaliods tropane Belladonna leaf (Deadly nightshade leaf) ( 葉 ) -Consists of the dried and flowering top of Atropa belladonna (Solanaceae ) -Atropa: Greek Fate who cuts the thread of life. -Belladonna: from Italian bella, meaning beautiful, and donna, meaning lady. (The

3 juice of the berry, when placed on eyes, causes dilation of the pupil thus giving a striking appearance.) -3/4 of the alkaloid mixture is (-)-hyoscyamine; 1/4 is atropine, which is formed by racemization during extraction. -Uses: parasympathetic depressant (spasmolytic agent); used as adjunctive therapy in the treatment of peptic ulcer; functional digestive disorders, including spastic mucous and ulcerative colitis; diarrhea; pancreatitis; control excess motor activity of urinary tract. yoscyamus leaf ( 葉 ) -dried leaf and flowering and fruiting top of yoscyamus niger (Solanaceae). -contains 3/4 of hyoscyamine and 1/4 of scopolamine. -Uses: parasympathetic. Stramonium leaf ( 羅葉 ) -dried leaf and flowering and fruiting top of Datura strmonium (Solanaceae). -contains principly hyoscyamine with small portion of scopolamine and trace of atropine. -Uses: anticholinergic. yoscyamine C 3 C2 -usually obtained from species of yoscyamus or other genera of Solanaceae. -readily hydrolyzed by boiling in dilute acids or alkalies to form tropine and tropic acid. C 3 C2 C 3 + C 2 -Uses: anticholinergic.

4 Scopolamine C 3 C2 Anticholinergic; central nervous system depressant used for preanesthetic sedation and for obstetric amnesia in conjunction with analgesics; prevention of nausea and vomiting associated with motion sickness. Cocaine C 3 C 3 C 3 C 3 + ecgonine benzoic acid cocaine -obtained from the leaves of Erytroxylum coca and its variety or prepared by semisynthesis from plant-derived ecgonine. - Erytroxylum: from Greek, meaning red wood (color of the plant). - coca: Spanish name for tree. -cultivated in Bolivia, Colmbia, and Peru; each produces about 50,000 metric tons of leaves a year. -uses: local anesthetic. -other physiological effect: (1) powerful central nervous system stimulant with a strong abuse potential; (2) euphoric excitement is rapidly produced when cocaine is sniffed. -acute toxicity from excess dose: (1) extreme agitation, restless, confusion, blurred version, and tremors; (2) induces paranoid thinking, hallucinations, cardiac arrhythmia, acute myocardial infartion. Quinoline alkaloids Cinchona bark (Peruvian bark) -dried bark of the stem and the root of Cinchona succirubra or its hybrids, or other species of Cinchona and heir hybrids.

5 - Cinchona: named in honor of the countess of Chinchon. - succirubra: means juice. -indigenous to the Andes of Ecuador and Peru. -grow at an elevation of 1000 to 3000 meters, cultivated in Indonesia and India. -trees that are 6-9 years ild possess the maximum amount of alkaloids. -contained some 25 closely related alkaloids, the most important of which are quinine, quinidine, cinchinine, and cinchonidine. -uses: treatment of malaria fever. Quinine -obtained from bark of Cinchona species. -use: antimalarial -mechanism: intercalation of the quinoline moiety into the DA of the plasmodium parasite. Quinidine -obtained from bark of Cinchona species. -a stereoisomer of quinine. -use: treatment of cardiac arrhythmias. Isoquinoline alkaloids Ipecac ( ) -consists of dried rhizome and roots of Cepaelis ipecacuanha (Brazilian ipecac) or

6 Cepaelis acuminata (icaragua or Panama ipecac). -contains emetine. -uses: treatment of drug overdose and in certain poisonings (syrup), produces emesis through a local irritant effect on the gastrointestinal mucosa and a central medullary effect by stimulation of the chemoreceptor trigger zone. Emetine ( ) C 2 5 -uses: antiamebic by inhibiting polypeptide chain elongation; possesses expectorant and emetic properties. Curare or South American arrow poison -Crude dried extract from the bark and stem of Strychnos castelnaei. -Curare: Indian word for poison. -Crude extract exhibits a paralyzing effect on voluntary muscle by blocking nerve impulses to skeletal muscles at myoneural junction. -Tubocurarine is the most important constituents. + -a bisbenzylisoquinoline quaternary aklaloids. -a skletal muscle relaxant to secure muscle relaxation in surgical procedures without deep anesthesia. tubocurarine pium ( ) -air-dried milky exudates obtained by incising the unripe capsules of Papaver somniferum (Papaveraceae) ( ). -opium: Greek, meaning poppy juice. -Papaver: Latin, means poppy. -somniferum: Latin, means to produced sleep. -an annual herb with large, showy, solitary flowers that vary in color from white to

7 pink or purple. -first cultivated in diterranean region, then introduced into India by Alexander the Great. -cutivation is controlled internationally by the International arcotics Control Board of the United ations. -contain morphine, codeine, noscapine, papaverine, and thebaine. -uses: anageic hypnotic, narcotic, Morphine C the most important opium alkaloid. -contains a phenolic and an alcoholic hydroxyl group. -used as narcotic analgesics; strongly hypnotic and narcotic; induced nausea, vomiting, constipation, and habit formation. eroine (Diacetylmorphine) C 3 Ac Ac -formed by acetylation of morphine. More potent than morphine. ydromorphine C 3 6

8 -6- replaced by a ketone. -more potent than morphine. -less nausea and constipation. Codeine C 3 6 -obtained from opium or prepared by morphine methylation. -anticough ydrocodone C 3 6 -anticough and antitissue. Synthetic analgesic nacortics CC 2 5 thadone peridine Features possessed by central acting analgesics (1) a central quaternary carbon. (2) a tertiary nitrogen. (3) a phenyl group or isostere attached to central carbon. (4) a two carbon bridge separating the central carbon and the tertiary nitrogen.

9 Paspaverine -occurs in opium -smooth muscle relaxant. Tolerance and enkephalin receptor Enkephalins Tyr-Gly-Gly-Phe-t Tyr-Gly-Gly-Phe-Leu Endophines Antidote of morphine: aloxone Abstinence of morphine 8-12 hr: lacrimation, rhinorrhea, yawning, diaphoresis, restless sleep 20 hr: gooseflesh, dilated pupil, agitation, tremors, 2-3 days: weakness, insomnia, chills, intestine cramps, nausea, vomiting, diarrhea, violent yawning, muscle aches in the legs, severe low back pain, elevation of blood pressure, diaphoresis, wave of gooseflesh. Indole alkaloids Rauwolfia Serpentina ( 度 ) -dried root of Rauvolfia serpentina (Apocynaceae)( ) -Rauvolfia: in honor of Dr. Leonhard Rauwoff, a noted 16 th century German botanist, physician, and explorer. -Serpentina: refers to the long, tapering, snakelike roots of the plant. -used by the medicine men of India to treat snakebite and insanity for centuries. -contain reserpine, resinanamine, and δ-yohimbine. -excert hypotensive effect by depletion of norepinephrine through inhibition of

10 catecholamine storage in postganglionic adrenergic endings. Reserpine 3 CC -chief alkaloid from Rauvolfia serpenina. -uses: antihypertensive and tranquilizer. Rescinnamine 3 CC -occurs in several speies of Rauvolfia. -uses: antihypertensive. Deserpine (11-desmethoxyreserpine) 11 3 CC -obtained from Rauvolfia canescens. -uses: antihypertensive and tranquilizer. Catharanthus (periwinkle)( )( ) -dried whole plat of Catharanthus roseus (Apocynaceae) -originated in Madagascar. -folkore used as hypoglycemic agent. -peripheral granulocytopenia and bone marrow depression in rats was observed by Canadian group of oble, Beer, and Cutts. -continued study led to the isolation of vinblastine, which produced severe leukopenia in rats. -more than 70 different alkaloids have isolated from Catharanthus.

11 Vinblastine C 2 C 3 CC 3 C 2 C 3 CC 3 CC 3 -the salt of an alkaloid extracted from Catharanthus. -uses: treatment of odgkin s disease, lymphocytic lymphoma, advanced testicular carcinoma, and breast cancer. Vincristine C 2 C 3 CC 3 C 2 C 3 CC 3 CC 3 C -obtained from Catharanthus. -no cross-resistance has been observed between vincristine and vinblastine. -uses: treatment of acute leukemia, odgkin s disease, lymphosarcoma, and neuroblastoma. ux Vomica ( ) -dried, ripe seed of Strychnos nux-vomica (Loganiaceae) -Strychnos: Greek name for poisonous plant. -nux-vomica: from two Latin words and means a nut that xauses vomiting. -a tree about 12 meters tall; native to East Indies. -Fruit is berry with 3-5 seeds. -contained strychnine and brucine (dimethoxystrychnine) -uses: commercial sources for strychnine and brucine.

12 Strychnine -obtained from nux vomica. -produces excitation of all parts of the central nervous system and block inhibitory spinal impulses at the postsynaptic level; leads to an exaggeration in reflexes with resulting tonic convulsion. Physostigma ( ) -dried, ripe seed of Physostigma venenosum (Leguminosae) -Physostigma: Latin, means an inflated or bladderlike stigma. -venenosum: Latin, means full of poison. -a perennial woody climber native to West Africa. -contains physostigmine, eseramine, etc. Physostigmine C 3 C 3 C C 3 -obtained from Physostigma venenosum. -uses: reversible inhibition of cholinesterase; miosis (contraction of ciliary muscle); decrease in intraocular pressure. Ergot ( ) -dried sclerotium of Claviceps purpurea developed on the plants of rye, Secale cerreale (Gramineae). - Claviceps: clublike character of the sclerotium. -purpurea: refers to its purpur color. -At present, ergot alkaloids are obtained on a commercial scale from both parasitic and saprophytic sources. -contains errgonovine, ergotamine, and ergotoxine.

13 -The medicinally useful alkaloids, either natural or semisynthetic, are all derivative od (+)-lysergic acid. -uses: sources of ergot alkaloids; oxytocic. Ergonovine R C 3 R = C 3 C 2 -soluble in water. -xytocic effect is noted within 5 minutes (orally, subcutaneously, or intramuscularly). -Vasoconstrictor action is much less marked. -increase the frequency and amplitude of uterine contractions; decrease blood loss from postpartum uterus. Ergotamine R C 3 R = 3 C -a specific anagesic in treatment of migraine. -reduced extracranial blood flow and decreases the amplitude of pulsation in the cranial arteries. Lysergic acid diethylamide (LSD) R C 3 R = (C 2 5 ) 2 -dose not occur in nature. -producev a predominant central sympathetic stimulation that parallels a slight depression. -the most active and most specific psychotomimetic agent known.

14 Imidazole alkaloids Pilocarpus ( 葉 ) -consists of the leaflet of Pilocarpus jaborandi. -Shrubs indigenous ton Brazil. -contains pilocarpine. Pilocarpine C 2 5 -obtained from Pilocarpus jaborandi Pilocarpus jaborandi. -stimulates the muscarinic receptors in the eye, causing constriction of the pupil and contraction of the ciliary muscle. -uses: treatment of glaucoma. Alkaloid amines Ephedra (ma huang) -entire plant or the overground portion of Ephedra sinica (Gnetaceae) -ma: means astringent; huang: means yellow. -used as a medicine in China for more than 5000 years. Ephedrine C 3 C 3 -obtained from Ephedra spp. or by reductive condensation between L-1-phenyl-1-acetylcarbinol and methylamine.

15 C Acetyl-CoA C 3 C 3 C C 3 C 3 -uses: potent sympathomimetic that stimulates α, β1, and β2 adrenergic receptors; causes vasoconstriction and cardiac stimulation; produced a rather lasting rise in blood pressure. Colchicine ( ) CC 3 -obtained from Colchicum autumnale (Liliaceae) or other species of Colchicum. -inhibit leukocyte migration and reduceds lactic acid production by leukocytes which results in a decreased deposition of uric acid. -reduction in phagocytosis which decreases inflammatory response. -uses: treatment of gout; doubling of chromosomes in plant genetics. Purine bases purine caffeine theophylline theobromine Caffeine -occurs in coffee (Coffea arabica), tea (Thea sinensis), cacao (Theobroma cacao), and kola (Cola nitida). -CS stimulant. Theophylline -occurs in tea. -uses: smooth muscle relaxants for the symptomatic relief or prevention of bronchial

16 asthma; diuretic. Theobromine -obtained from te dried seed of cacao. -little CS stimuation. -uses: diuretic and smooth muscle relaxant.

PHARMACOGNOSY. 4. Reserpine is indicated in: A. gastroduodenal ulcer B. depression C. arterial hypertension D. schizophrenia E. pregnancy.

PHARMACOGNOSY. 4. Reserpine is indicated in: A. gastroduodenal ulcer B. depression C. arterial hypertension D. schizophrenia E. pregnancy. PHARMACOGNOSY 1. The following structural features are essential for the spasmolytic activity of atropine: A. tropanol ring B. pseudotropanol ring C. morphinan ring D. quaternary nitrogen atom E. integrity