alkaloids written report

7/27/2019 Alkaloids written report

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Group 1

3DPH

Amican, Aegan Matthew

Ares, Karen Gem

Ballester, Ruvie Ann

Barcelona, Mark Joseph

Calleja, Katherine Carmen Isabel

Capuno, Christelle Venus

ALKALOIDS

I. Characteristics and PropertiesThese are the organic product of natural and synthetic origin which are basic in natureand contain one or more than one nitrogen compound normally in heterocyclic in nature,and posses specific physiological action on human and animal body, when use in smallquantities

A. Physical Property

Color- In general, Alkaloids are colorless but some may be colored.

Physical Form- Most are crystalline solids- Few are amorphous

SolubilityFree alkaloid bases

-

are invariably found to be fairly soluble in organic solvents,such as: either, chloroform, relatively non-polar solvents(hexane, benzene, petroleum ether), immiscible solvent, loweralcohols (methanol, ethanol); but they are either practicallyinsoluble or very sparingly soluble in water.

Alkaloidal salts

- are almost freely soluble in water, relatively less soluble inalcohol and mostly either insoluble or sparingly soluble inorganic solvents: Examples Atropine sulphate and morphinehydrochloride are much more soluble in water than theircorresponding bases i.e., atropine and morphine.

There are a few exceptions to the above stated generalizations, namely:

(i) Certain alkaloid bases are water soluble, but these may be solely regarded asexceptions rather than any specific rule, such as: ephedrine, colchicine,pilocarpine;the quaternary alkaloid-base like berberine and tubocurarine;caffeine-base readily extracted from tea with water.

(ii) Narceine and pilocarpine are insoluble in organic solvents, whereas morphine issparingly soluble in organic solvents viz., solubility in either 1:5000.


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(iii) Certain alkaloidal salts, for instance: lobeline hydrochloride and apoatropinehydrochloride are found to be soluble in organic solvent like chloroform.

(iv) Some alkaloidal salts are sparingly soluble in water whereas others areextremely watersoluble, such as: Quinine sulphate-soluble in 1:1000 parts ofwater, Quinine hydrochloride soluble in 1:1 part of water.

B. Chemical Property

N-in the Molecule

- The number of N-atoms vary from the bear minimum one in amolecule e.g., cocaine, to even five in amolecule e.g.,ergotamine.

- these N-atoms are normally present as a part of theheterocyclic ring in the alkaloid molecule

e.g., quinine,reserpine,strychnine,vinblastineand yohimbine

- whereas there are certain alkaloids that contain the N-atom in

the aliphatic side chaino e.g., ephedrine, mescaline.

- N-atom in the tertiary-amine form (R3N)

o e.g.,morphine, reserpine; lesser in the secondary-amine form (R2NH

o e.g., ephedrine; and very rarely in the primary-amine

form (RNH2)


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o e.g., nor-pseudo-ephedrine.

- Furthermore, whenever N-atom occurs either inthe tertiary- or secondary-form, it essentially constitutes as an integralpart of the ringsystem, precisely the heterocyclic ring system.

- Noticeably, the tertiary N-atoms wherein only two of the bonds areinvolved in a ring, the methyl moiety is usually found as the third

component, for instance: N-methyl group in morphine, cocaine,colchicine, dextro methorphan, codeine, physostigmine, vinblastine,vindesine etc.

- Hence, methyl moiety seems to be the only alkyl group that has beenfound to be substituted on the N-atom.

- In some very specific cases, the N-atom occurs in the quaternaryammonium form (R4N+ . X) e.g., tubocurarine chloride

- Nevertheless, the quaternary ammonium compounds are logically andtechnically not regarded as alkaloids by virtue ofthe following two particular reasons, namely:

N-atom does not possess a H-atom, and Chemical properties are quite different.

O-in the MoleculeInvariably, these specific alkaloids are found in the solid state, with a

few exceptions where the oxygenated alkaloids usually occur as non-volatile liquids, suchas: pilocarpine.

Basicity (Alkalinity)In general, the alkaloids are basic (alkaline) in reaction, by virtue of the presence

of N-atom present in the molecule. Hence, these are prone to the formation of theirrespective salts with various acids.

Degree of Basicity:mostly depends upon the prevailing influence caused due to the electrostatic

status of the N-atom present in the alkaloid molecule, for instance, the number of N-atompresent in the alkaloid, whether the N-atom is located in the ring or in the side-chain, thepresence of alkyl group (e.g., methyl) to the N-atom etc.

Another vital factor, is the presence of pri-, sec-, tert-, or quaternary N-atom oratoms in it. They are eventually reflected by the different dissociation constant values (i.e.,pKa values) with regard to various alkaloids

II. Classification

Chemical Classification

This is a most accepted way of classification of alkaloids. The maincriterion for chemical classification is the type of fundamental(normally heterocyclic) ringstructure present in alkaloids. The alkaloidal drugs are broadly categorized into twodivisions.

o True alkaloids(heterocyclic alkaloids) are divided into twelve groupaccording to the nature of their heterocyclic ring

o Protoalkaloids or biological amine and pseudoalkaloids


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Taxonomic Based in their Familye.g. Solanaceous,Papilionaceous without reference their chemical type ofalkaloids present & another according to genus. e.g.. ephedra, cinchonaetc. Pharmacological based: Their pharmacological activity or response.For example:

1. Analgesic alkaloids

2. Cardio active alkaloids etc. Do not have chemical similarity intheir group.

Biosynthetic Classification

This method gives significance to the precious from which the alkaloidsare biosynthesized in the plant. Hence, the varity of alkaloids with differenttaxonomic distribution and physiological activities can be brought under samegroup if they are derived from same procedure. E.g. all indole alkaloids fromtryptophan are grouped together. The alkaloidal drugs are catagorised on the factwhether are derived from amino acid procedure as ornithine, lysine, tyrosine,phenylalanine, tryptophen, etc.According to this alkaloids are usually classifiedby their common molecular precursors, based on the metabolic pathway used to

construct the molecule. When not much was known about the biosynthesis ofalkaloids, they were grouped under the names of known compounds, even somenon-nitrogenous ones (since those molecules' structures appear in the finishedproduct; the opium alkaloids are sometimes called "phenanthrenes", forexample), or by the plants or animals they were isolated from. When more islearned about a certain alkaloid, the grouping is changed to reflect the newknowledge, usually taking the name of a biologically-important amine that standsout in the synthesis process.

o Pyridine group:piperine,coniine,trigonelline,arecaidine,guvacine,pilocarpine,cytisine,nicotine,sparteine,pelletierine

o Pyrrolidine group: hygrine,cuscohygrine,nicotineo Tropane group: atropine, cocaine, ecgonine, scopolamine, catuabineo Quinoline group: quinine, quinidine, dihydroquinine, dihydroquinidine,

strychnine,brucine, veratrine, cevadineo Isoquinoline group: The opium alkaloids (morphine, codeine, thebaine,

Isopapa-dimethoxy-aniline, papaverine, narcotine, sanguinarine, narceine,hydrastine, berberine), emetine, berbamine,oxyacanthin

o Phenethylamine group: mescaline, ephedrine, dopamine, amphetamineo Indole group:

o Tryptamines: DMT, N-methyltryptamine, psilocybin, serotonino Ergolines: the ergot alkaloids (ergine, ergotamine, lysergic acid, LSD

etc.o Beta-carbolines: harmine, harmaline, yohimbine, reserpineo Rauwolfia alkaloids: Reserpine

o Purine group:o Xanthines: caffeine, theobromine, theophylline

o Terpenoid group:o Aconite alkaloids: aconitine
http://en.wikipedia.org/wiki/Metabolic_pathwayhttp://en.wikipedia.org/wiki/Metabolic_pathwayhttp://en.wikipedia.org/wiki/Pyridinehttp://en.wikipedia.org/wiki/Piperinehttp://en.wikipedia.org/wiki/Coniinehttp://en.wikipedia.org/wiki/Trigonellinehttp://en.wikipedia.org/w/index.php?title=Arecaidine&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Guvacine&action=edit&redlink=1http://en.wikipedia.org/wiki/Pilocarpinehttp://en.wikipedia.org/wiki/Cytisinehttp://en.wikipedia.org/wiki/Nicotinehttp://en.wikipedia.org/wiki/Sparteinehttp://en.wikipedia.org/w/index.php?title=Pelletierine&action=edit&redlink=1http://en.wikipedia.org/wiki/Pyrrolidinehttp://en.wikipedia.org/wiki/Hygrinehttp://en.wikipedia.org/wiki/Cuscohygrinehttp://en.wikipedia.org/wiki/Nicotinehttp://en.wikipedia.org/wiki/Tropanehttp://en.wikipedia.org/wiki/Atropinehttp://en.wikipedia.org/wiki/Cocainehttp://en.wikipedia.org/wiki/Ecgoninehttp://en.wikipedia.org/wiki/Scopolaminehttp://en.wikipedia.org/wiki/Catuabinehttp://en.wikipedia.org/wiki/Quinolinehttp://en.wikipedia.org/wiki/Quininehttp://en.wikipedia.org/wiki/Quinidinehttp://en.wikipedia.org/wiki/Tropanehttp://en.wikipedia.org/wiki/Dihydroquininehttp://en.wikipedia.org/wiki/Strychninehttp://en.wikipedia.org/wiki/Brucinehttp://en.wikipedia.org/wiki/Veratrinehttp://en.wikipedia.org/w/index.php?title=Cevadine&action=edit&redlink=1http://en.wikipedia.org/wiki/Isoquinolinehttp://en.wikipedia.org/wiki/Opiumhttp://en.wikipedia.org/wiki/Morphinehttp://en.wikipedia.org/wiki/Codeinehttp://en.wikipedia.org/wiki/Thebainehttp://en.wikipedia.org/w/index.php?title=Isopapa-dimethoxy-aniline&action=edit&redlink=1http://en.wikipedia.org/wiki/Papaverinehttp://en.wikipedia.org/wiki/Narcotinehttp://en.wikipedia.org/wiki/Sanguinarinehttp://en.wikipedia.org/w/index.php?title=Narceine&action=edit&redlink=1http://en.wikipedia.org/wiki/Hydrastinehttp://en.wikipedia.org/wiki/Berberinehttp://en.wikipedia.org/wiki/Emetinehttp://en.wikipedia.org/wiki/Phenethylaminehttp://en.wikipedia.org/wiki/Mescalinehttp://en.wikipedia.org/wiki/Ephedrinehttp://en.wikipedia.org/wiki/Dopaminehttp://en.wikipedia.org/wiki/Amphetaminehttp://en.wikipedia.org/wiki/Indolehttp://en.wikipedia.org/wiki/Phenethylaminehttp://en.wikipedia.org/wiki/Tryptaminehttp://en.wikipedia.org/wiki/N-methyltryptaminehttp://en.wikipedia.org/wiki/Psilocybinhttp://en.wikipedia.org/wiki/Serotoninhttp://en.wikipedia.org/wiki/Ergolinehttp://en.wikipedia.org/wiki/Ergothttp://en.wikipedia.org/wiki/Erginehttp://en.wikipedia.org/wiki/Phenethylaminehttp://en.wikipedia.org/wiki/Lysergic_acidhttp://en.wikipedia.org/wiki/LSDhttp://en.wikipedia.org/wiki/Beta-carbolinehttp://en.wikipedia.org/wiki/Harminehttp://en.wikipedia.org/wiki/Harmala_alkaloidhttp://en.wikipedia.org/wiki/Yohimbinehttp://en.wikipedia.org/wiki/Reserpinehttp://en.wikipedia.org/wiki/Purinehttp://en.wikipedia.org/wiki/Xanthinehttp://en.wikipedia.org/wiki/Caffeinehttp://en.wikipedia.org/wiki/Theobrominehttp://en.wikipedia.org/wiki/Theophyllinehttp://en.wikipedia.org/wiki/Terpenoidhttp://en.wikipedia.org/wiki/Aconitehttp://en.wikipedia.org/wiki/Aconitinehttp://en.wikipedia.org/wiki/Aconitinehttp://en.wikipedia.org/wiki/Aconitehttp://en.wikipedia.org/wiki/Terpenoidhttp://en.wikipedia.org/wiki/Theophyllinehttp://en.wikipedia.org/wiki/Theobrominehttp://en.wikipedia.org/wiki/Caffeinehttp://en.wikipedia.org/wiki/Xanthinehttp://en.wikipedia.org/wiki/Purinehttp://en.wikipedia.org/wiki/Reserpinehttp://en.wikipedia.org/wiki/Yohimbinehttp://en.wikipedia.org/wiki/Harmala_alkaloidhttp://en.wikipedia.org/wiki/Harminehttp://en.wikipedia.org/wiki/Beta-carbolinehttp://en.wikipedia.org/wiki/LSDhttp://en.wikipedia.org/wiki/Lysergic_acidhttp://en.wikipedia.org/wiki/Phenethylaminehttp://en.wikipedia.org/wiki/Erginehttp://en.wikipedia.org/wiki/Ergothttp://en.wikipedia.org/wiki/Ergolinehttp://en.wikipedia.org/wiki/Serotoninhttp://en.wikipedia.org/wiki/Psilocybinhttp://en.wikipedia.org/wiki/N-methyltryptaminehttp://en.wikipedia.org/wiki/Tryptaminehttp://en.wikipedia.org/wiki/Phenethylaminehttp://en.wikipedia.org/wiki/Indolehttp://en.wikipedia.org/wiki/Amphetaminehttp://en.wikipedia.org/wiki/Dopaminehttp://en.wikipedia.org/wiki/Ephedrinehttp://en.wikipedia.org/wiki/Mescalinehttp://en.wikipedia.org/wiki/Phenethylaminehttp://en.wikipedia.org/wiki/Emetinehttp://en.wikipedia.org/wiki/Berberinehttp://en.wikipedia.org/wiki/Hydrastinehttp://en.wikipedia.org/w/index.php?title=Narceine&action=edit&redlink=1http://en.wikipedia.org/wiki/Sanguinarinehttp://en.wikipedia.org/wiki/Narcotinehttp://en.wikipedia.org/wiki/Papaverinehttp://en.wikipedia.org/w/index.php?title=Isopapa-dimethoxy-aniline&action=edit&redlink=1http://en.wikipedia.org/wiki/Thebainehttp://en.wikipedia.org/wiki/Codeinehttp://en.wikipedia.org/wiki/Morphinehttp://en.wikipedia.org/wiki/Opiumhttp://en.wikipedia.org/wiki/Isoquinolinehttp://en.wikipedia.org/w/index.php?title=Cevadine&action=edit&redlink=1http://en.wikipedia.org/wiki/Veratrinehttp://en.wikipedia.org/wiki/Brucinehttp://en.wikipedia.org/wiki/Strychninehttp://en.wikipedia.org/wiki/Dihydroquininehttp://en.wikipedia.org/wiki/Tropanehttp://en.wikipedia.org/wiki/Quinidinehttp://en.wikipedia.org/wiki/Quininehttp://en.wikipedia.org/wiki/Quinolinehttp://en.wikipedia.org/wiki/Catuabinehttp://en.wikipedia.org/wiki/Scopolaminehttp://en.wikipedia.org/wiki/Ecgoninehttp://en.wikipedia.org/wiki/Cocainehttp://en.wikipedia.org/wiki/Atropinehttp://en.wikipedia.org/wiki/Tropanehttp://en.wikipedia.org/wiki/Nicotinehttp://en.wikipedia.org/wiki/Cuscohygrinehttp://en.wikipedia.org/wiki/Hygrinehttp://en.wikipedia.org/wiki/Pyrrolidinehttp://en.wikipedia.org/w/index.php?title=Pelletierine&action=edit&redlink=1http://en.wikipedia.org/wiki/Sparteinehttp://en.wikipedia.org/wiki/Nicotinehttp://en.wikipedia.org/wiki/Cytisinehttp://en.wikipedia.org/wiki/Pilocarpinehttp://en.wikipedia.org/w/index.php?title=Guvacine&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Arecaidine&action=edit&redlink=1http://en.wikipedia.org/wiki/Trigonellinehttp://en.wikipedia.org/wiki/Coniinehttp://en.wikipedia.org/wiki/Piperinehttp://en.wikipedia.org/wiki/Pyridinehttp://en.wikipedia.org/wiki/Metabolic_pathwayhttp://en.wikipedia.org/wiki/Metabolic_pathway


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o Steroids: solanine, samandaris (quaternary ammonium compounds):muscarine, choline, neurine

o Vinca alkaloids: vinblastine, vincristine. They are antineoplastic and bindsfree tubulin dimers thereby disrupting balance between microtublepolymerization and delpolymerization resulting in arrest of cells in metaphase.

o Miscellaneous: capsaicin, cynarin, phytolaccine, phytolaccotoxin

III. Structures

1. Are basic nitrogen containing compounds2. Show great diverse structure and origins as well as pharmacological actions3. The only common factor found is the presence of the Nitrogen atom

R

RNH CH

CH2 R

Alkaloids are a group of nitrogen- containing bases. But few of them are derived frompurines or pyrimidines, while the majority of them are produced from amino acids .

Classifications of Alkaloids based on presence of nitrogen atom in a heterocyclic ringsystem

1. Non Heterocyclic Alkaloids or Atypical Alkaloids/ Proto-alkaloids- These molecules have nitrogen atoms which are not a part of any ring system

Examples :

Ephedrine:

Colchicine:2. Heterocyclic Alkaloids or Typical Alkaloids

- These have nitrogen as part of a cyclic ring system. Further divided into 14groups based on ring structure containing nitrogen

Heterocycle Example
http://en.wikipedia.org/wiki/Steroidhttp://en.wikipedia.org/wiki/Solaninehttp://en.wikipedia.org/w/index.php?title=Samandari&action=edit&redlink=1http://en.wikipedia.org/wiki/Ammoniumhttp://en.wikipedia.org/wiki/Muscarinehttp://en.wikipedia.org/wiki/Cholinehttp://en.wikipedia.org/wiki/Neurinehttp://en.wikipedia.org/wiki/Vinca_alkaloidshttp://en.wikipedia.org/wiki/Vinblastinehttp://en.wikipedia.org/wiki/Vincristinehttp://en.wikipedia.org/wiki/Capsaicinhttp://en.wikipedia.org/w/index.php?title=Cynarin&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Phytolaccine&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Phytolaccotoxin&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Phytolaccotoxin&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Phytolaccine&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Cynarin&action=edit&redlink=1http://en.wikipedia.org/wiki/Capsaicinhttp://en.wikipedia.org/wiki/Vincristinehttp://en.wikipedia.org/wiki/Vinblastinehttp://en.wikipedia.org/wiki/Vinca_alkaloidshttp://en.wikipedia.org/wiki/Neurinehttp://en.wikipedia.org/wiki/Cholinehttp://en.wikipedia.org/wiki/Muscarinehttp://en.wikipedia.org/wiki/Ammoniumhttp://en.wikipedia.org/w/index.php?title=Samandari&action=edit&redlink=1http://en.wikipedia.org/wiki/Solaninehttp://en.wikipedia.org/wiki/Steroid


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Pyrrolizidine

Tropane (Piperidine/ N-methyl-pyrrolidine)

Quinoline

Isoquinoline


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Aporphine(reducedisoquinoline/naphthalene)

Quinolizidine

Indole or Benzopyrole

Indozolidine

Imidazole or glyoxaline


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Purine (pyrimidine/imidazole)

Steroidal (some combined as glycosides)

Terpenoid

IV. Uses

Some alkaloids focus their range in a particular part of the body. Those that most affect us are:

1. Nervous sytem

-Exert a stimulation role in the CNS (Caffeine, theobromine, strychnine) that in verysmall doses can be convulsive.

- Scopolamine of henbane (Hyoscamus niger) have a calming role, hence they areused as sedatives.

- Opium, which is extracted from the latex of the capsule of the poppy is the mainingredient of some sleeping pills

- Aconitine, initially stimulating but later can be paralyzing- Strychnine causes violent and painful spasms


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- Scopolamine is responsible for mydriasis or dilation of the pupil- Eserin from calabar bean is used to contract the pupils of the eyes- Digitalis acts on the heart muscle

2. Digestive System- Some are very toxic to the digestive system causing violent irritation to the gastric

mucosa with typical manifestations such as diarrhea and vomiting.

-Among these are castor oil plant (Ricinus communis) that contain alkaloid ricininewhich has been used as a purgative but extremely dangerous because a couple ofchewed seeds can be fatal to a child.

3. Circulatory sytem- Resperine from (Rowulfa vomitoria) is used to lower blood pressure- Sparteine is used to increase metabolism and encourage the elimination of fluids in

people with obesity4. Respiratory system

-scoparin contained in the flowers of common broom (Cytisis scoparuis) hass been usedto combat respiratory diseases-ephedrine has been used as a decongestant as a treatment for bronchial asthma andhas been later banned by the FDA because it possesses stimulant properties.

5. Psychotropicsn- affects the mind, altering perceptiona. Hallucinogens- distorted illusion of reality-mescaline from peyote (Lophophora williamsii)-canabine from cannabis (Cannabis sativa)- harmaline from Syrian rue (Paganum harmala)- ergotoxine from ergot (Claviceps purpurea)-muscarine from mushroom amanita (Amanina muscarina)

b. Narcotics- induces a dreamy state-Opium-Morphine

-Codeine

c. Stimulants-state of euphoria and well being- cocaine is extracted form coca leaves (Erythroxylon coca)-nicotine is obtained from tobacco (Nicotiana tobacum)-solanaceae is an addictive stimulant and a dangerous poison even in low doses- caffeine is present in coffee, tea, cacao, orange tree, lemon

V. Example of Plantsa) Nervous system:

o Stimulating role in CNS- caffeine (coffee and especially tea), theobromine

(cacao) or strychnine(nux vomica),o Calming role, sedatives- scopolamine from henbane leaf, foliage, root and

seed (Hyoscyamus Niger), morphine from the latex of poppy (Papaversomniferum main ingredient of sleeping pills)

o Initially stimulating but paralyzing - aconitine from the root of aconite (Aconitum carmichaelii)

o In muscles(pupil), to dilate - scopolamine of henbane (HyoscyamusNiger)
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o Contracts muscles eserine from calabar bean (Physostigmavenenosum) in pupil, digitalis (Digitalis sp) on the heart

b) Digestive system:o Poisonous ricine in seeds of castor oil plant (Ricinus communis),

colchicines of autumn crocus (Colchicum autumnale), cynoglossine fromheliotrope (Heliotropium europaeum)

c) Circulatory System:o Circulatory vessels reserpine from Rauwolfia vomitoria ( lowers blood

pressure), sparteine of common broom Branch ends, Leaf, foliage, Seed(Cytisis scoparius) has opposite effect useful to inc. metabolism andelimination of fluids in people with obesity

d) Respiratory System:o Dilating bronchial tubes scoparin in the flowers of common broom

(Cytisis scoparius), ephedrine from different species of the genusEphedra (FDA in USA banned)

e) Psychotropics:o Hallucinogens strong poisonous drugs: mescaline from peyote

(Lophophora williamsii), cannabine from cannabis ( Cannabis sativa),

harmaline from Syrian rue (Peganum harmala), ergotoxine from ergot(Claviceps purpurea), muscarine from mushroom Amanita ( Amaninamuscarina)

o Narcotics morphine produced from opium extracted the latex of thepoppy (Papaver somniferum), codeine and heroin are derived fromit(morphine)

o Stimulants- cocaine from coca leaves (Erythroxylon coca), nicotine fromtobacco leaf and foliage (Nicotiana tabacum)

VI. Extraction Procedure

1. Sample Preparation

The plant material is reduced to a moderately coarse powder using grinders andsieves, to facilitate maximum effective contact of the solvent with the ruptured alkaloidbearing tissues and cells.

In the case of plant substances that are rich in oils and fats, such as: seeds,kernels, these non-alkaloidal chemical components need to be eliminated completely byextraction with a suitable non-polar solvent like n-hexane, light petroleum ether, in asoxhlet apparatus, which would not extract the alkaloids in question.

2. Liberation of Free Alkaloidal BaseAlkaloids invariably occur as the salt of acids, such as oxalates and tannates.

Therefore, when the plant substance is exposed to an alkaline medium, the alkaloidalsalts are readily converted to the corresponding alkaloid bases.

Factors Affecting the Choice of Alkali to be Used(a) Natural state of the alkaloids- the salt of a strongly basic alkaloidwith a mineral acid

usually tends to undergo cleavage under the influences of a stronger base. Likewise,thecorresponding salt of a weakly basic alkaloid and a relatively weak organic acid shallrequire arather weaker base for its cleavage.(b) Chemical characteristics of the alkaloidal base: The usage of strong alkali e.g., NaOHor KOH should be avoided as far as possible by virtue of the fact that certain alkaloidsundergo hydrolysis on prolonged contact with a strong base.
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3. Extraction of Alkaloidal Base

The extraction of alkaloidal base may be accomplished by three different types ofsolvents:

(a) Extraction with Water-Miscible Solvents(b) Extraction with Water-Immiscible

(c) Extraction with Water

4. Purification of Alkaloidal Extract(a) Extraction with Acid Solution-dilute H2SO4 is always preferred over HCl forgeneral use in the extraction of alkaloids. The acid solution is rendered alkalinewith dilute NH4OH solution to liberate the alkaloids which is then extracted with anorganic solvent. The solvent is removed under reduced pressure and the traces ofmoisture are removed with anhydrous sodium sulphate.(b) Precipitation of Alkaloid with Precipitating Reagent -accomplished by the

addition of a suitable precipitating reagent. It is further purified by filtration,recrystallization and ultimately decomposed to obtain the desired free alkaloid(s).

(c) Formation of Crystallized Alkaloidal Salt- by addition of an appropriate mineralor organic acid, such as: hydrochloric, hydrobromic, perchloric, sulphuric, oxalicand tartaric acids.(d) Various separation techniques- partition, ion-exchange and columnchromatography are invariably used for the purification of a host of alkaloids.

5. Fractionation of Crude Alkaloids(a) Fractional crystallization(b) Fractional distillation(c) Derivatization with low solubility products

Latest methods employed:

High performance liquid chromatography (HPLC)\High performance thin-layer chromatography (HPTLC)ChromatotronCounter-current distributionColumn chromatographyIon-exchange chromatography

Methods of Extraction

(a) Soxhlet Extraction Process-generally suitable for the extraction of alkaloids from powdered plant materials with thehelp of organic solvents

-the powdered drug is usually moistened with dilute ammonia solution and then packedloosely in the thimble of the Soxhlet apparatus;-and the organic solvent affords a deep penetration of the moist drug thereby allowing thegreatest possible extraction of the alkaloids from the exposed surfaces of the cells andtissues of the crude drug.-the solvent is filtered and evaporated in a Rotary Thin-Film Evaporator and the residue istreated further for the isolation of individual alkaloids.
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(b) Stas-Otto Process-treating the powdered and sieved drug substance with 9095% (v/v) ethanol, previouslyacidified with tartaric acid.-proportion of crude drug to solvent should be maintained as 1 Kg to 1 L.-alcohol is distilled off under vacuum and the resulting aqueous residue is treated withpetroleum-ether (60-80C) to remove the fatty components completely.

-the combined aqueous extract is filtered and evaporated to dryness preferably in aRotary Thin-Film Evaporator under vacuum.-residue is extracted with absolute ethanol thereby dissolving the total alkaloids.

(c) Kippenbergers Process-powdered and sieved plant substance is digested with solution of tannin (100 g) inglycerol (500 g) at a constant temperature of 40C for a duration of 48 hours.-resulting mixture is further heated to 50C so as to help in the complete coagulation ofproteinous substances, cooled to ambient temperature and finally filtered.-resulting filtrate is thoroughly shaken with petroleum ether to get rid of faulty materials,and the last traces of petroleum ether is removed from the extract by heating either on awater-bath or exposure to Infra-Red Lamp.

-the fat-free crude plant extract is subsequently acidified and shaken with chloroform,successively to remove the bulk of the alkaloids, namely, atropine, codeine, colchicine,narcotine, nicotine, papaverine, spartenine and thebaine.-the resulting residual extract may still contain narceine, curarine and morphine. However,narceine and morphine may be isolated by passing freshly generated CO2 directly intoextract so as to convert the alkali hydroxide into their corresponding carbonate, which isthen ultimately subjected to solvent extraction using a mixture of alcohol and chloroform.Finally, the third alkaloid, curarine, may be extracted by agitation with a mixture of equalvolumes of ether and chloroform.-combination ofKippenbergers process and Stas-Otto process by its application to thefinal alcoholic extract obtained by the latter process is found to give better separation ofalkaloids.

VII. References

http://www.botanical-online.com/english/alkaloids.htm

http://www.epharmacognosy.com/2012/07/general-characteristics-of-alkaloids.html

http://www.thecabinchiangmai.com/archive/opiates___opioids__morphine__codeine____other_medications

http://www.liberherbarum.com/Minor/UK/IN0001.htm

http://www.erowid.org/archive/rhodium/chemistry/alkastract.html

http://www.weizmann.ac.il/plants/aharoni/PlantMetabolomeCourse/June192007.pdfhttp://www.epharmacognosy.com/2012/07/general-characteristics-of-alkaloids.html

http://www.epharmacognosy.com/2012/07/classification-of-alkaloids.html

http://www.authorstream.com/Presentation/prem07-1580026-complete-info-alkaloids-ppt/

http://www.us.elsevierhealth.com/media/us/samplechapters/9780702029332/9780702029332_2.pdf
http://www.epharmacognosy.com/http://www.botanical-online.com/english/alkaloids.htmhttp://www.epharmacognosy.com/2012/07/general-characteristics-of-alkaloids.htmlhttp://www.thecabinchiangmai.com/archive/opiates___opioids__morphine__codeine____other_medicationshttp://www.thecabinchiangmai.com/archive/opiates___opioids__morphine__codeine____other_medicationshttp://www.liberherbarum.com/Minor/UK/IN0001.htmhttp://www.facebook.com/l.php?u=http%3A%2F%2Fwww.erowid.org%2Farchive%2Frhodium%2Fchemistry%2Falkastract.html&h=nAQEPU16Phttp://www.weizmann.ac.il/plants/aharoni/PlantMetabolomeCourse/June192007.pdfhttp://www.epharmacognosy.com/2012/07/general-characteristics-of-alkaloids.htmlhttp://www.epharmacognosy.com/2012/07/classification-of-alkaloids.htmlhttp://www.authorstream.com/Presentation/prem07-1580026-complete-info-alkaloids-ppt/http://www.us.elsevierhealth.com/media/us/samplechapters/9780702029332/9780702029332_2.pdfhttp://www.us.elsevierhealth.com/media/us/samplechapters/9780702029332/9780702029332_2.pdfhttp://www.us.elsevierhealth.com/media/us/samplechapters/9780702029332/9780702029332_2.pdfhttp://www.us.elsevierhealth.com/media/us/samplechapters/9780702029332/9780702029332_2.pdfhttp://www.authorstream.com/Presentation/prem07-1580026-complete-info-alkaloids-ppt/http://www.epharmacognosy.com/2012/07/classification-of-alkaloids.htmlhttp://www.epharmacognosy.com/2012/07/general-characteristics-of-alkaloids.htmlhttp://www.weizmann.ac.il/plants/aharoni/PlantMetabolomeCourse/June192007.pdfhttp://www.facebook.com/l.php?u=http%3A%2F%2Fwww.erowid.org%2Farchive%2Frhodium%2Fchemistry%2Falkastract.html&h=nAQEPU16Phttp://www.liberherbarum.com/Minor/UK/IN0001.htmhttp://www.thecabinchiangmai.com/archive/opiates___opioids__morphine__codeine____other_medicationshttp://www.thecabinchiangmai.com/archive/opiates___opioids__morphine__codeine____other_medicationshttp://www.epharmacognosy.com/2012/07/general-characteristics-of-alkaloids.htmlhttp://www.botanical-online.com/english/alkaloids.htmhttp://www.epharmacognosy.com/

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