biosynthetic classification of alkaloids
TRANSCRIPT
Alkaloids
• “Basic nitrogenous compound, contains one or morenitrogen in heterocyclic ring system having markedphysiological action on human and animals when use in smallquantities””.
Classification of alkaloids• 1. Chemical classification of alkaloids• 2. Taxonomical classification of alkaloids• 3. Pharmacological classification of alkaloids• 4. Biosynthetic classification of alkaloids
Common amino acid precursors:
Phenylalanine
Tyrosine
Tryptophan
Histidine
Anthranilic acid
Lysine
Ornithine
BIOSYNTHETIC CLASSIFICATION OF
ALKALOIDS
Alkaloids are classified on the basis of biosynthetic
precursors from which these are obtained . These
include
Ornithine derived alkaloids
Tryptophan derived alkaloids
Lysine derived alkaloids
Phenylalanine derived alkaloids
Tyrosine derived alkaloids
Histidine derived alkaloids
Alkaloids derived from substance other than amino
acids.
• Some of the general reactions that are of particular
importance include: decarboxylation (removal of
carboxyl group or carbon dioxide) and transamination
(transfer of an amino group from one molecule to another
without the formation of ammonia) of the amino acids to
yield a corresponding amine or aldehyde.
• These can react to form a Schiff base which, in turn can
react with carbanion in a Mannich-type condensation.
General reactions for biosynthesis of alkaloids
Alkaloid formation may require the involvement of only one
molecule of amino acid, or 2 molecules of the same AA, or
less commonly, 2 molecules of different AA or else several
molecules of the same AA.
ORNITHINE DERIVED ALKALOIDS
It includes:
Tropane alkaloids
Pyrrolidine alkaloids`
TROPANE ALKALOIDS
(ATROPINE, HYOCYAMINE, HYOSINE, SCOPOLAMINE)
B.S: Atropa belladona (deadly nightshade), Datura stramonium( thornapple), Hyosyamus niger(henbane).
Family: solanaceae
Part used: dried leaves and flowering tops
Uses: 1.Atropine is classified as anti cholinergic drugs.
Atropine can also be used in SLUDGE syndrome( salivation, lacrimation, urination, diaphoresis, GIT motility and emesis) caused by organophosphate poisoning.
Hyoscine is used as antispasmodic.
COCAINEo B.S: Erythroxylum coca, Erythroxylum novogranatense
o Common name. Coca leaves
o Family: Erythroxylaceae
o Part used: Leaves
o Uses: cocaine is a CNS stimulant.
it is also used as local anesthetic.
Biosynthesis of tropane alkaloids
TRYPTOPHAN DERIVED ALKALOIDS
These include
INDOLE ALKALOIDS
QUINOLINE ALKALOIDS
Indole alkaloidsPhysostigma alkaloids• Botanical source. Physostigma venonosum
• Common name: calabar bean
• Family : Leguminosae
• Part used: dried ripe seeds
• Main constituents: physostigmine , isophysostigmine, physovenine.
• Uses: These are the cholinesterase inhibitors and used as antidote for atropine poisoning.
• Also used to treat glaucoma.
Ergot alkaoidsB.S: Claviceps purpureaFamily: HypocrealesPart used: Dried sclerotium of the fungusMain constituents: Ergotamine, Ergometrine, ErgocristineUses: Ergotamine is used to treat migraine and clustur headache.
Ergometrine acts as oxytocic agent and also used in post-partal haemorrhage.
Vinca alkaloidsB.S: Catharanthus roseusCommon name: periwinkleFamily: Apocynacea Part used: whole plantConstituents: Vincristine, VinblastineUses: these alkaloids have anticancerproperties.
Rauwolfia alkaloidsB.S: Rauwolfia serpentinaCommon name: indian snakerootFamily: Apocyanacea Part used: leavesConstituents: serpentine, reserpine, ajmaline, ajmalacine,Uses: used as antihypertensive and antiarrhythmic agent.
Biosynthesis of Vinca alkaloids
Quinoline alkaloidsB.S: Cinchona Succirubra, C. calisaya, C. officinalisCommon name; QuinaFamily: RubiaceaePart used: Dried Bark Constituents: Quinine, quinidine, cinchonine,
cinchonidine.Uses: Quinine is a classical antimalarial.
Quinidine is used for cardiac arrythmias and atrial fabrillation.
LYSINE DERIVED ALKALOIDS
These include
Lobelia spp
pepper spp
Lobelia alkaloids• B.S: Lobelia inflata
• Common name: indian tobacco
• Family: Lobeliaceae
• Part used: dried aerial parts
• Constituents: lobeline, isolobeline, lobelanine, lobeladine
• Uses: it is used in chronic bronchitis and spasmodic asthma.
lobeline
Pepper alkaloids• B.S: Piper nigrum
• Common name: black pepper, kali mirch
• Part used: dried , unripe fruit
• Family : Piperaceae
• Constituents: piperine and piperittene
• Uses: piper is used as condiment and for chronic bronchitis.
ALKALOIDS DERIVED FROM TYROSINE
Isoquinoline alkaloids
papaver alkaloids
cephaelis alkaloids
Papaver alkaloids
• B.S: Papaver somniferum
• Family: papaveraceae
• Part used: dried milky latex of poppy capsule.
• constituents: Morphine, codiene, thebaine, Norcotine, Narciene, papaverine
• Uses: Morphine is used as analgesic.
codiene is used in cough preparations.
Cephaelis alkaloids
B.S: C.ipecacuanhaCommon name: IpecacPart used: roots and rhizomeFamily: RubiaceaeConstituents: cephaline, psychotrine, Emetine, Uses: ipecacuanha is used as expectorant,and emetic and in the treatment ofAmeobic dysentry.
Emetine
BIOSYNTHESIS OF OPIUM ALKALOIDS:
------- L-Dopa ------ Dopamine+
3,4 – dipydroxyphenylpyruvic acid
PAPAVERINE ----------------- norlaudanosoline( ket intermediate)
Reticuline
Saluteridine
Saluteredinol
Alkaloids derived from phenylalanine
• EPHEDRINE, PSEUDOEPHEDRINE :-• B.S –It consists of dried young stem of Ephedra
gerardiana and Ephedra nebrodensis.
• Synonym—Ma-huang).
• Family:- Ephedraceae
• C.C:-- It contains the amino alkaloids : Ephedrine, nor-ephedrine, n-methyl ephedrine, pseudo-ephedrine.
• Uses: it is used in Asthma, hay fever, flu, cold medications.
Biosynthesis of Ephedrine
HISTIDINE DERIVED ALKALOIDS
These alkaloids include Imidazole alkaloids. e.g Pilocarpine
It is used in the treatment of glaucoma and atropine poisoning.
Purines are derivatives of a heterocyclic nucleus consisting of a six-membered Pyrimidine ring fused to a five-membered Imidazole ring.
Purines are Psudo alkaloids (Are not derived from amino acids but have nitrogen in a heterocyclic ring)
Purine alkaloids
Alkaloids obtained from precursors other than Amino Acids
xanthine
theophyillinecoffeine theobromine
Purine alkaloids
They are all methyl derivatives of xanthine.
Theobromine
• B.S. Theobroma cacao
• Family: sterculiaceae
• Part used: seeds
• Uses: Cocoa has nutritive, stimulant and diuretic properties.
Theobromine is used as a diuretic. It has less action on the central nervous system than caffeine but is more diuretic.
CaffeineB.S: Coffee arabica
Family: Rubiaceae
Uses: caffeine is used in combinations with antipyretics and analgesics, cold and flu medication.
also used as Ingredient in non-alcoholic beverages and “energizing” beverages.
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