ALKALOIDS,ISOLATION - PowerPoint PPT Presentation

1 / 28
About This Presentation
Title:

ALKALOIDS,ISOLATION

Description:

Alkaloids exhibiting basic character are very much sensitive to decomposition & cause a problem during storage their salt formation. The alkaloids may contain one ... – PowerPoint PPT presentation

Number of Views:1986
Avg rating:3.0/5.0
Slides: 29
Provided by: sys187
Category:

less

Transcript and Presenter's Notes

Title: ALKALOIDS,ISOLATION


1
ALKALOIDS,ISOLATION ITS
CLASSIFICATION


By - Jaspreet Rekhi www.rhombnet.com
2
DEFINATION OF ALKALOIDS
  • These are the organic products of natural or
    synthetic origin which are basic in nature
    contain one or more than one nitrogen atoms,
    normally of heterocyclic nature possess
    specific physiological actions on human or animal
    body, when used in small quantites.
  • The term is derived from the word alkali-like
    hence they resemble some of characters of
    naturally occuring amines.

3
TYPES OF ALKALOIDS
4
  • TRUE ALKALOIDS These contain heterocyclic
    nitrogen, which is derived from amino acids
    always basic in nature. These alkaloids are toxic
    normally present in plants as salts of organic
    acids e.g. Morphine, Codeine

5
  • PROTO ALKALOIDS These are simple amines in which
    the nitrogen is not in heterocyclic ring. Some
    times these are considered as biological amines.
    These are basic in nature prepared in plants
    from amino acids e.g. Colchicine, Ephedrine

6
  • PSEUDO ALKALOIDS These includes mainly
    steroidal, terpenoid alkaloids purines. These
    are not derived from amino acids.
  • These do not show many of the typical characters
    of alkaloids but give the standard qualitative
    tests for alkaloids
  • e.g. caffeine

7
PHYSICAL PROPERTIES
  • With few exceptions, all the alkaloids are
    colourless, crystalline solids with a sharp
    melting point.
  • Some of the alkaloids are amorphous gums, while
    other are liquid volatile in nature.
  • Some alkaloids are coloured in nature e.g.
    berberine is yellow.
  • Free bases of alkaloids are soluble in organic,
    non-polar, immiscible solvents.
  • The salts of most bases are soluble in water.

8
  • Free bases are insoluble in water.
  • The alkaloids containing quarternary bases are
    only water soluble.
  • Some of pseudoalkaloids protoalkaloids show
    higher solubility in water e.g. caffeine is
    freely soluble in water.

9
CHEMICAL PROPERTIES
  • Most of the alkaloids are basic in reaction, due
    to the availability of lone pair of electrons on
    nitrogen.
  • The basic character of the alkaloid is enhanced
    if the adjacent functional groups are electron
    releasing.
  • The alkaloid turns to be neutral or acidic when
    the adjacent functional groups are electron
    withdrawing like amide group which reduces the
    availability of the lone pair of electrons.

10
  • Alkaloids exhibiting basic character are very
    much sensitive to decomposition cause a problem
    during storage their salt formation.
  • The alkaloids may contain one or more no. of
    nitrogen. It may exist in the form as
  • Primary amine (R-NH2) e.g. mescaline
  • Secondary amine (R2-NH) e.g. ephedrine
  • Tertiary (R3-N) e.g.atropine
  • Quartanary ammonium compounds e.g.
    tubocurarine hydrochloride

11
CHEMICAL TESTS FOR ALKALOIDS
  • MAYERS REAGENT
  • (pot. mercuric iodide solution)
  • DREGENDORFFS REAGENT
  • (pot. bismuth iodide solution)
  • WAGNERS REAGENT
  • (iodine-pot.iodide solution)
  • HAGERS REAGENT (picric acid solution)
  • Cream coloured ppt.
  • Reddish brown ppt.
  • Reddish brown ppt.
  • Yellow coloured ppt.

12
GENERAL ISOLATION PROCEDURE FOR ALKALOIDS
Ground Plant Material
  1. Defat with Hexane
  2. Extract with methanol, filter, concentrate

Methanolic Crude Extract
  1. Treat with 1 aqueous HCl
  2. Partition with diethyl ether

Aqueous-acid phase
Diethyl ether phase Concentrate (neutral
compounds)
  1. Alk. with NH4OH
  2. Partition with CHCl3

Chloroform extract (primary, secondary
tertiary alkaloids)
Aqueous alkaloids (quarternary Alkaloids)
13
ROLE OF ALKALOIDS IN PLANTS
  • They are reserve substances with an ability to
    supply nitrogen.
  • They might be the defensive mechanisms for plants
    growing in dry regions to protect from grazing
    animals, herbivores insects.
  • They might have a possible role as growth
    regulatory factors in the plants.
  • These are end products of detoxification
    mechanisms in plants.
  • These are present in conjugation with the plant
    acids such as meconic acid hence acting as
    carriers within the plants for transportation of
    such acids.

14
PHARMACOLOGICAL ACTIVIES OF ALKALOIDS
  • Anticancer e.g. vinca
  • Hypotensive e.g. rauwolfia
  • Oxytocic e.g. ergot
  • Narcotic analgesic e.g. opium
  • Anticholinergic e.g. belladona, datura
  • Local anasthetic e.g. coca
  • Antimalarial e.g. cinchona
  • Expectorant e.g. vasaka

15
CHEMICAL CLASSIFICATION OF ALKALOIDS
  • TRUE ALKALOIDS
  • PYRROLE
  • PYRROLIDINE
  • DERIVATIVES
  • e.g. Hygrine, Cocca species

16
  • Pyrrolizidine Derivatives
  • e.g. senecionine, seneciphylline

17
  • Piperidine pyridine derivativese.g.
    arecoline, lobeline

18
  • TROPANE DERIVATIVES
  • e.g. Atropine, hyoscine, cocaine

19
  • QUINOLINE
  • DERIVATIVES
  • e.g. Quinine, quinidine, cinchonine

20
  • ISOQUINOLINE
  • DERIVATIVES
  • e.g. Morphine,
  • codeine,
  • berberine,
  • emetine

21
  • APORPHINE
  • (REDUCED
  • ISOQUINOLINE-NAPTHALENE)
  • DERIVATIVES
  • e.g. boldine

22
  • INDOLE DERIVATIVES
  • e.g. ergometrine,
  • ergotamine,
  • reserpine,
  • vincristine,
  • vinblastine

23
  • IMIDAZOLE
  • DERIVATIVES
  • e.g. Pilocarpine,
  • isopilocarpine

24
  • NORLUPINANE DERIVATIVES
  • e.g. Cytisine,
  • lupanine

25
  • PURINE DERIVATIVES
  • e.g. Theophylline, caffeine,
  • theobromine

26
  • STEROIDAL
  • DERIVATIVES
  • e.g. protoveratrine, solanidine

27
PSEUDO ALKALOIDS
  • DITERPENES
  • e.g. Aconitine, aconine, hypoaconitine
  • PROTO ALKALOIDS
  • ALKYLAMINES
  • e.g. Ephedrine,pseudoephedrine, colchicine

28
Thanks for downloadingDo Comment plz.
By - Jaspreet Rekhi www.rhombnet.com
Write a Comment
User Comments (0)
About PowerShow.com