alkaloids.pptx

Alkaloids- the term alkaloids are used to designate basic nitrogenous compounds of plant origin that are physiologically active. This ppt contains introduction of alkaloids, history, classification, property, function, uses of alkaloids, effects of alkaloids on human, extraction of alkaloids, biosynthesis of alkaloids, heterogeneous alkaloids, non heterogeneous alkaloids, solubility of alkaloids, chemical property of alkaloids, function of alkaloids in plant.

1. ALKALOIDS

2. CONTENTS Introduction History Classification Properties Functions Uses
Effects of alkaloids on humans Extraction of alkaloids Biosynthesis of alkaloids Conclusions References

3. Introduction The name alkaloids was introduced in1819 by the German chemist Friedrich Wilhelm Meibner, and is derived from Latin , root alkali which inturn, comes from the Arabic- meaning ashes of plant
The term alkaloids are used to designate basic nitrogenous compounds of plant origin that are physiologically active
Alkaloids are produced by a large variety of organisms including bacteria, fungi, plants and animals
The first individual alkaloid, morphine was isolated in 1804 from the opium poppy Friedrich serturner, the German chemist to isolate morphine from opium poppy

4. Alkaloids have a wide range of pharmacological activities including antimalarial (e.g: quinine) Antiasthma(e g: ephedrine) Cholinometric(e.g: galantamine) Vasodilatory(e.g: vincamine) Antiarrhythmic (e.g : quinidine) Analgesic (e.g: morphine) Antibacterial (e.g : Chelerythrine) Antihyperglycemic activities (e.g : piperine) Other alkaloids posses psychotropic ( e.g : psilocin) and other stimulant activities (E.g : Cocaine, caffeine, nicotine, theobromine) Toxic alkaloids like adropine, tubocurarine

5. History Alkaloid containing plants have been used by humans since ancient times for therapeutic and recreational purposes The Odyssey of Homer reffered to a gift given to Helen by the Egyptian queen, a drug bringing oblivion
It was believed that the gift was an opium containing drug
A Chinese book on houseplants written in 1 st – 3 rd centuries BC mentioned a medicinal use of ephidra and opium poppy The extract from plants containing toxic alkaloids, such as aconitine and tubocurarine were used since antiquity for poisoning arrows

6. The first complete synthesis of an alkaloid was achieved in 1886 by the German chemist Albert Ladenburg
NAMING: Many individual names are formed by adding the suffix “ine” to the species or genus name
E.g: Atropine is isolated from the plant Atropa belladona
Strychnine is obtained from the seed of the Strychnos nux-vomica L.

7. Classification Biosynthetic classification: . In this particular instance the significance solely, lies to the precursor from which the alkaloids are produced in the plant biosynthetic ally
Example: indole alkaloids derived from tryptophan Piperidine alkaloids derived from lysine
Pyrrolidine alkaloids derived from ornithine
Phenylethylamine alkaloids derived from tyrosine Imidazole alkaloids derived from histidine

8. Chemical classification: The main criterion is the presence of the basic heterocyclic nucleus
Examples:- Pyrrolidine alkaloids ( Hygrine ) Piperidine alkoloids( Lobeline) Pyrrolizidine alkaloids ( Senecionine) Tropane alkaloids (Atropine) Quinoline alkaloids (quinine)

9. Pharmacological classification:- This is used as a strong basis for the general classification of the Widespectrum of alkaloids derived from the plant kingdom such as analgesics, cardiovascular drugs, CNS- stimulants and depressants, dilation of eye pupil , mydriatics, anticholinergics, sympathomimetics, antimalarial, purgatives
Examples:- Morphine as narcotic analgesic
Quinine as antimalarial Strychnine as reflex excitability Lobeline as respiratory stimulant
Boldine as choleretics and laxatives

10. Taxonomic classification:- This particular classification essentially deals with the 'taxon’ i.e., taxonomic category The most common taxa are the genus, subgenus, species, subspecies and variety
Cannabinaceous alkaloids:- e.g- Cannabis sativa (Hemp) Rubiaceous alkaloids:- e.g:- Cinchona (quinine) Solanaceous alkaloids:- eg:- Atropa belladona L. , Capsicum annum L. ( Sweet potato,paprika)

11. Non-heterogenous alkaloids

12. Heterogeneous alkaloids

13. PROPERTIES OF ALKALOIDS PHYSICAL PROPERTIES Condition:-
Most alkaloids are crystalline solids
Few alkaloids are amorphous solids
E.g: emetine
Some are liquids that are either:- Volatile e.g:- Nicotine and coniine or non- volatile – e.g:- Pilocarpine and hyoacine

14. Colour: The majority of alkaloids are colourless but some are coloured E g: Colchicine and berberine are yellow
Canadians is orange
The salts of sanguinarine are copper-red Solubility: Both alkaloidal bases and their salts are soluble in alcohol Generally the bases are soluble in organic solvents and insoluble in water

15. Exceptions: Bases soluble in water : caffeine, ephedrine, Codeine, colchicine, Pilocarpine and Quaternary ammonium bases
Bases insoluble or sparingly soluble in certain organic solvents: morphine in ether, theobromine and theophylline in benzene
Salts insoluble in water: quinine monosulphate
Salts soluble in organic solvents: Lobline and apoatropine, hydrochloride are soluble in chloroform

16. CHEMICAL PROPERTIES Most of the alkaloids are basic in nature, due to the availability of lone pair electrons on the nitrogen The basic character of the alkaloid compound is enhanced if the adjacent functional groups are electron releasing The alkaloids turn to be neutral or acidic when the adjacent functional groups are electron withdrawing like amide group which reduces the availability of lone pair of electrons Their salt formation with an inorganic acid prevents many a time their decomposition In the natural form, the alkaloids exists either in free State as amine or as salt with acid or alkaloid N- oxides

17. Functions of alkaloids in plants They may act as the reservoirs of protein synthesis They may act as protective substances against the insect or animal attacks
Like hormones, they may function as plant stimulants or regulators in activities like growth, metabolism and reproduction They may function as detoxicating agents by methylating, condensing and cyclizing the compounds whose accumulation might cause damage to the plant They may be utilised as the source of energy in case of deficiency in carbon dioxide assimilation
Source of nitrogen in case of nitrogen deficiency

18. Uses of alkaloids Alkaloids showed strong biological effects on animal and human organisms in very small doses
Alkaloids are present not only in human daily life in food and drinks but also as stimulant drugs
They showed anti-inflammatory, anticancer, analgesics, local anaesthetic and pain relief, neuropharmacologic, antimicrobial, antifungal and many other activities Alkaloids are useful as diet ingredients, supplements and pharmaceuticals in medicine and in other applications in human life
Alkaloids are also important compounds in organic synthesis for searching new semisynthetic and synthetic compounds with possibly better biological activity than parent compounds

19. Effects of alkaloids on humans Alkaloids are produced by many plants as defense chemicals not only mainly against herbivores but also against microbial pathogens Many alkaloids exhibit a pronounced toxicity in animal models and humans A major target in animals is the nervous system and many alkaloids structurally resemble neurotransmitters Because of structure similarity, they can interfere with neurotransmitter receptors or ion channels and thus modulates neuronal signal transduction

20. Also other organs can be affected by toxic alkaloids such as the liver, kidney, heart and circulation, gatrointestinal tract and reproductive organs At a molecular level, alkaloids can interfere with membrane permeability, membrane proteins (ion channels and receptors), enzymes and other proteins, DNA, RNA and corresponding proteins, electron chain and the cytoskeleton Because of these pharmacological properties, some alkaloids can be used in medicine to treat infections, health disorders and even cancer

21. Extraction of alkaloids STAS- OTTO METHOD: The technique involve the distribution of alkaloidal bases between acid or aqueous solution and immiscible organic solvents Stage 1 :- The powdered material is moistened with water and mixed with alkali like sodium and potassium carbonate, ammonia, lime. Make a paste with water, dry, repowder
Stage 2 :- Extract the free alkaloids by hot continuous percolation with chloroform or any other organic solvents

22. Stage 3:- agitate the chloroform solution witb successive portion of dilute sulphuric acid separating the aqueous layer before adding the next portion of acid Stage 4 :- make the mixed aqueous liquid alkaline with ammonia, collect the precipitate that forms, wash with water and dry

23. Biosynthesis of alkaloids Biological precursor of most alkaloids are amino acids such as, ornithine, lysine, phenylalanine, tyrosine, tryptophan, histidine, aspartic acid,etc. SYNTHESIS OF SCHIFF’S BASES
Schiff’s bases can be obtained by reacting amines with ketones or aldehydes These are common method of producing C=N bonds

24. In the biosynthesis of alkaloids such reactions may take place within a molecule. Such as in the synthesis of piperidine

25. Mannich reaction An integral component of the Mannich reaction in addition to an amine and carbonyl compound is a carbanion which plays the role of the nucleophile in the nucleophilic addition to the ions formed by the reaction of amine and carbonyl

26. The Mannich reaction can produce both intermolecularly and intramolecularly

27. Dimer alkaloids In addition to the described monomeric alkaloids, there are dimeric and even trimeric and tetrameric alkaloids formed upon condensation of two, three and four monomeric alkaloids Dimeric alkaloids are usually formed from monomers of same type
Mannich reaction resulting in e.g: Vocamine
Condensation of aldehydes with amines resulting in toxiferine

28. Conclusions Alkaloids are basic nitrogenous compounds which are of great medicinal properties It becomes toxic when given in high quantity And it acts as medicine when given in small quantity

29. References Andreas Luch(2009), Molecular, clinical, environmental toxicology, Springer,p20
R.H.F Manske(1965).,The alkaloid chemistry and physiology,vol VIII , Newyork, Academic press, p-673 www.pharmacology.in/alkaloidsclassification

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