Chemical analysis of Chemical analysis of MPM that contain MPM that contain

alkaloids alkaloids

AlkaloidsAlkaloids are complex organic are complex organic compounds of basic nature compounds of basic nature containing nitrogen. They are containing nitrogen. They are vegetable origin (seldom animal vegetable origin (seldom animal origin) and have very strange, origin) and have very strange, specific physiological effect on specific physiological effect on the body. The name “alkaloid” is the body. The name “alkaloid” is derived from Arabian derived from Arabian olkaliolkali – – alkali and Greek alkali and Greek eidoseidos – similar to – similar to alkali.alkali.

Typical alkaloids are derived from plant sources. they are basic. They contain one or more nitrogen atoms(usually in a heterocyclic ring) and they usually have a marked physiological action on man or other animals

Some 150 years of alkaloid chemistry had resulted by the mid-1940s in the isolation of about 800 alkaloids: the new technology of the next years increased this figure to the order of 10 000.

ClassificationClassification

I. BIOGENETIC CLASSIFICATIONAlkaloids are usually classified according to the nature of their

chemical structure:1. Protoalkaloids2. True alkaloids3. Pseudoalkaloids

1. Ephedrine

2. Chemical classification2. Chemical classification (suggested by Oryekhov) (suggested by Oryekhov) – – alkaloids are divided into groups accoring to nitrogen alkaloids are divided into groups accoring to nitrogen bearing heterocycle.bearing heterocycle.

There areThere are:: Pyrolydine derivativesPyrolydine derivatives Pyperidine derivativesPyperidine derivatives Pyridine derivativesPyridine derivatives Pyrolysidine derivativesPyrolysidine derivatives Quinolysidine derivativesQuinolysidine derivatives Quinoline derivativesQuinoline derivatives Isoquinoline derivativesIsoquinoline derivatives Indole derivativesIndole derivatives Imidazole derivativesImidazole derivatives Acridine derivativesAcridine derivatives Purine derivativesPurine derivatives Tropane derivativesTropane derivatives

Pyrolydine

Pyrolysidine

Tropane Indole Imidazole

Purine

Pyperidine

Pyridi ne

Quinoline

Isoquinoline

Quinolysidine

Acridine

3. “Pseudoalkaloid” has been introduced to cover alkaloids, which are formed from terpenes:1) Terpenoid alkaloids. They are monoterpenes, sesquiterpenes and diterpenes (e.g. Alkaloids of Aconitum, Delphinium and Taxus).

Aconitine

2) Steroidal alkaloids are characterised by the cyclopentenoperhydrophenanthrene nucleus.Solasodine, veratrum, alkamine esters and their glycoside are the main alkaloids of this group. They occur in genus: Solanum, Veratrum.

Solasodine

II. Phylogenetic or botanical classification

(on a close botanical and chemical affinity)

All isolated alkaloids from plants from the same family or genus are combined (ipecacuanha alkaloids, colchicine alkaloids, etc.).

III. Pharmacological classification

Pharmacological classification divides alkaloids according to its pharmacological effects on: narcotic analgesics, sympatholytic means, alkaloids that inhibit the cough center, etc.

IV. Biosynthetic classification

combines alkaloids according to the name of amino acids (precursors) from which they are synthesized.

Ornithine - pyrrolidine, pyrrolizidine, tropane some pyridine alkaloids derivatives.Lysine – Quinolizine and some piperidine alkaloidsTyrosine - isoquinoline alkaloidsTryptophan - indole, quinoline, pyridine and some piperidine alkaloidsHistidine - imidazole alkaloids such as pilocarpineGlycine and aspartic acid - purine alkaloids

Medical plant materials containing alkaloids storage according the list B.But Nux vomica seeds (Strychni semen), Colchicum corm (Colchici bulbotubera recens), Scopoliae carniolicae rhizomata - the list A.

Biosynthesis

Asometine (Schiff base)

N-hydtoximethilic derivate

Acid amide CH-acidic component

Condensation product

Alkaloids accumulate in 4 types of tissues:

1) those that are actively growing;2) in epidermal and hipodermal;3) in the facing of vascular bundles;4) in latex vessels

PropertiesPropertiesMost alkaloidsa are well-defined crystalline substances

which unite with acids to form salts. In the plant they may exist in the free state, as salts or as N-oxides (see below). ln addition to the elements carbon, hydrogen and nitrogen, most alkaloids contain oxvgen. A f'ew, such as coniine from hemlock and nicotine from tobacco, are oxygen-free and are liquids.

Although coloured alkaloids are relatively rare, they are not unknown; berberine, for example is yellow and the salts of sanguinarine are copper-red.

A knowledge of the solubility of alkaloids and their salts is considerable pharmaceutical importance.

Not only are alkaloidal substances often administered in solution, but also the differences in solubility between alkaloids and their salts provide methods for the isolation of alkaloids from the plant and their separation from the nonalkaloidal substances also present.

While the solubilities of different alkaloids and salts show considerable variation, as might be expected from their extremely varied structure, it is true to say that the free bases are frequently sparingly soluble in water but soluble in organic solvents; with salts the reverse is often the case, these being usually soluble in water but sparingly soluble in organic solvents. For example, strychnine hydrochloride is much more soluble in water than is strychnine base.

It will soon be realized that there are many exceptions to the above generalizations, caffeine (base) being readily extracted from tea with water and colchicine being soluble in either acid, neutral or alkaline water. Again, some alkaioidal salts are sparingly soluble-for example. quinine sulphate is only soluble to the extent of 1 part in 1000 parts of water, although 1 part quinine hydrochloride is soluble in less than 1 part of water.

General precipitate reactoins General precipitate reactoins on alkaloidson alkaloids

With Major’s reagentsWith Major’s reagents (bichloride mercury (bichloride mercury solution on potassium iodide solution) – white solution on potassium iodide solution) – white or yellow precipitate.or yellow precipitate.

With Vagner’s and Bushard’s reagentsWith Vagner’s and Bushard’s reagents (iodine solution in potassium iodide) – brown (iodine solution in potassium iodide) – brown precipitates that are the compounds of precipitates that are the compounds of alkaloids hydroiodides with iodine.alkaloids hydroiodides with iodine.

With Drehendorf’s reagentWith Drehendorf’s reagent (bismuth (bismuth subnitrate solution potassium iodide and subnitrate solution potassium iodide and acetic acid) – orange-red or brick-red acetic acid) – orange-red or brick-red sediment.sediment.

With Marmer’s reagentWith Marmer’s reagent (cadmium iodide (cadmium iodide solution in potassium iodide) – white or solution in potassium iodide) – white or yellowish sediment, often soluble in surplus yellowish sediment, often soluble in surplus reagent.reagent.

With tannin solutionWith tannin solution – whitish or – whitish or yellowish amorphic precipitate.yellowish amorphic precipitate.

With picric acid solutionWith picric acid solution – yellow – yellow precipitate.precipitate.

With Zonnenshtein’s reagentWith Zonnenshtein’s reagent (phosphoromolybdenic acid) – (phosphoromolybdenic acid) – yellowish amorphic precipitate, yellowish amorphic precipitate, getting dark-blue or green colour.getting dark-blue or green colour.

With silicon tugsten acidWith silicon tugsten acid – – whitish precipitate.whitish precipitate.

The most sensative reagent on alkaloids is a modified Dragendorif's reagent.

Caffeine and some other alkaloids do not give these precipitate.

Care must be taken in the application of these alkaloidal tests, as the reagents also give precipitates with proteins. During the extraction of alkaloids from the plant and subsequent evaporation, some proteins will not be extracted and others will be made insoluble( denatured) by the evaporation process and may be filtered out.

Extraction of alkaloidsProcess A. The powdered material is moistened with water and mixedwith lime which combines dilute acids, tannins and other phenolicsubstances and sets free the alkaloids (if they exist in the plant as salts).Extraction is then carried out with organic solvents such as ether orpetroleum spirit. The concentrated organic liquid is then shaken withaqueous acid and allowed to separate. Alkaloid salts are now in theAqueous liquid, while many impurities remain behind in the organic liquid.Process B. The powdered material is extracted with water or aqueousalcohol containing dilute acid. Pigments and other unwanted materialsare removed by shaking with chloroform or other organic solvents. Thefree alkaloids are then precipitated by the addition of excess sodiumbicarbonate or ammonia and separated by filtration or by extractionwith organic solvents.

Biological Effect and Application Biological Effect and Application of Alkaloidsof AlkaloidsAlkaloid-bearing plants are used in Pharmacy and Alkaloid-bearing plants are used in Pharmacy and

Medicine with different purposes. They are used Medicine with different purposes. They are used directly at the Chemist’s shops for manufacturing of directly at the Chemist’s shops for manufacturing of extracts and decoctions (thermopsis – Thermopsis extracts and decoctions (thermopsis – Thermopsis Lanceolata). The others are used for manufacturing Lanceolata). The others are used for manufacturing galenicals tinctures, extracts, neogalenicals. galenicals tinctures, extracts, neogalenicals. Alkaloids are produced from raw stuff in pure form Alkaloids are produced from raw stuff in pure form and then manufactured as: tablets, ampoules, drage.and then manufactured as: tablets, ampoules, drage.

Medical significance of alkaloids:Medical significance of alkaloids: analgetics (Poppy remedies)analgetics (Poppy remedies) hemostatics (Claviceps purpurea medicines )hemostatics (Claviceps purpurea medicines ) cardiovascular remedies (ephedra)cardiovascular remedies (ephedra) anticancer (autumn crocus remedies )anticancer (autumn crocus remedies ) spasmolytic (beladonna).spasmolytic (beladonna).It is not possible to describe all types of It is not possible to describe all types of

phamacological effects. Effects of some alkaloids on phamacological effects. Effects of some alkaloids on the human body are studied well. These substances the human body are studied well. These substances effect on specific receptors or influence enzyme effect on specific receptors or influence enzyme activity.activity.