alkaloids and extraction of alkaloids

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Text of alkaloids and extraction of alkaloids


2. HISTORY Alkaloid -the Arabic word - al-qali. Term alkaloid -coined by messiner -German pharmacist (1819). Totally more than 7000 compounds are known in only 5% of the plant species. Ninety five percent of plant species are still remain to be examined for alkaloids. 3. ALKALOIDS ACCORDING TO KOINGS (1880):-Naturallyoccurring organic bases whichcontains a Pyridine ring. 4. According toLadenburg Alkaloid are natural plant compound that have basic character and contains at least one nitrogen atom in heterocyclic ring. 5. ALKALOIDS Simply alkaloids are nothing but the basicnitrogenous compound, contains one or more nitrogen in heterocyclic ring system having marked physiological action on human and animals when use in small quantities. 6. STRUCTURE Alkaloids- 12000 structures known. Poisons Conine Narcotics Morphine Stimulants caffeine Medicine Taxol 7. FACTS AND NEWS EVIDENCE 1806 Pharmacy assistant Friedrich Wilhelm Serturner isolated morphine from poppy seeds Socrates died when he was forced to drink extract of hemlock containing coniine. Nicotine (tobacco) is used as very potent insecticide for fumigating green houses. Cleopatra used extracts containing atropine to dilate her pupil in order to appear more attractive; atropine in low doses dilates pupils of the eye. 8. GENERAL PROPERTIES OF ALKALOIDS 9. PHYSICAL PROPERTY 1.Most alkaloids are crystalline solid , but someare liquid e.g Volatile; --Nicotine , Coniine .Spartine. 10. Non-Volatile:- Pilocarpine , Hyoscine 11. 2.Majority of alkaloids are colorless but some are colored, e.g. Colchicine and berberine(yellow), canadine (orange)BERBERINECANADINE 12. SOLUBILITY :-difference in solubility used as a base for their isolation and purification from nonalkaloidal bases. The following can be mentioned :a)Both alkaloidal base and there salts are soluble in alcohol.b).Genarally bases are soluble in organic solvent and alkaloidal salts are soluble in water. 13. Alkaloid or its SaltWaterAlocohol EtherAtropine Atropine sulphate Morphine460 0.52 525 InsolubleChlorofor m 1 Insoluble340030050001525Morphine sulphate15.5565InsolubleInsoluble 14. CHEMICAL PROPERTIES 1.Salt formation :--Due to their basic character alkaloid reacts with acid to form salt --strong bases form salt with very weak acid. --weak bases forms salt with strong acid -- very weak bases form unstable salts.e.g caffeine , Narcotine , piperine. 15. 2).Amphoteric alkaloids :--can form salts with both acid and alkali. e.gPhenolic group :--morphine 16. Carboxylic group:--narciene (a narcotic alkaloid that occurs in opium) 17. 3)Effect of heat: Alkaloids are decomposed by heat, except strychnine and caffeine (sublimable). 4). Effect of light and oxygen : Decomposed when allowed to stand at a temperature above 70o C .For long time. Sensitivity varies in degree with different alkaloids. Decomposition occur rapidly and easily when an alkaloid is in solution than when it is in dry form. Most tertiary amine alkaloids are easily transformed to the n-oxides. 18. EFFECT OF ALKALIS. Weak alkalis liberate most alkaloids from their salts e.G. Nh3 Strong alkalis: such as aqueous naoh and KOH form salts with phenolic alkaloids. Hot alkalis: results hydrolysis of ester alkaloids e.G. Atropine, cocaine and physostigmine and cleavage of lactone ring, if present, to produce the corresponding acid, e.G. Pilocarpine is transformed to pilocarpic acid. 19. BASICITY OF ALKALOIDS :--The basicity of alkaloid is due to presence of a lone pair of electron on nitrogen atom. --The basicity increased if the adjacent group is electron releasing like alkali . -- the basicity decreases if the adjacent group is electron withdrawing like carbonyl and amide group. 20. EXTRACTION OF ALKALOIDS 21. STAS-OTTO METHODLOGO 22. STAS-OTTOThetechniquedistributionofMETHODinvolve alkaloidalthe basesbetween acid or aqueous solutionand immiscible organic solvent. 23. Method I: A) stage1:--Powdered material is moistened with water and mixed with alkali like sodium & potassium carbonate , ammonia, lime. Make a paste with water ,dry ,repowder.Concept :--Lime(calcium hydroxide),combines with acid , tannins, and other phenolic substances and sets free alkaloids. 24. Powdered drug Containing alkaloidal salts Defatted if necessaryMoisten & render alkaline with Na2CO3, lime, NH3Free alkaloidsExhaust with org. Solvent like chcl3, etherTotal extractsConc. & Shake with acid like dil. H2so4Aq. Acid soln (Alkaloidal salts)Make alkaline extract with immisicible solventResidual organic fraction (Pigments, fats & weak bases or chloroform soluble alkaloids sulphates)Residual aq. Fraction organic soln (alkaloidal bases) Remove solventcrude alkaloidal mixture LOGO 25. B).Stage2:-- extract the free alkaloids by hot continous percolation with chloroform or any other organic solvents. Concept :-the free alkaloids dissolve together with other substances soluble in solvent. C).Stage3:--agitate the chloroform soln. With successive portion of dil.Sulphuric acid separating the aqueous layer before adding the next portion of acid. Concept :-the alkaloids are converted into alkaloidal sulphates, which being soluble in water,pass into aqeous layer. 26. D)Stage4:--Make the mixed aqueous liquid alkaline with ammonia, collect the precipitate that forms, wash with water and dry. Concept :- Ammonia decomposes the alkaloidal sulphates forming ammonium sulphates ,soluble in water ,and the free alkaloid which being practicallyinsoluble in water is precipitated. 27. THANK YOU