biosynthetic classification of alkaloids

BIOSYNTHETIC CLASSIFICATION OF

ALKALOIDS

Presented by : M. Jamal

Email: jamalkhan616@gmail.com

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.

END