a brief introduction to alkaloids

1. PRESENTATION 0N ALKALOIDS
SHAMIL FAWAS A

2. INTRODUCTION
• The term alkaloid applies to naturally occuring basic compounds
having physiological action.
• The term is derived from ‘vegetable alkali’ (alk=alkali, oid=like)
• A true alkaloid has: a nitrogenatom as a part of heterocyclic system; a
complex molecular structure , it manifests significant pharmacological
activity and it is restricted to the plant kingdom.
• Alkaloids have been reported in various plant parts such as: a)in
whole aerial plant (Lobelia, Tylophora, Ephedra) b) in leaves (Datura,
Belladonna, Coca) c)in bark (Kurchi, cinchona) d) in stem (withania)
etc.

3. • Several alkaloids have been found in cultures of microorganisms, e.g., in
bacteria, in fungi and algae.
• The names of alkaloids have been derived from plants yielding them,
from physiological activity and from the discoverer.
• As per the chemical rules the names of all alkaloids should end in "ine".
• Alkaloids exhibit a variety of physical and chemical properties.
• All of them possess carbon, hydrogen and nitrogen and in most cases
oxygen as elements.

4. • The free alkaloids are insoluble or slightly soluble in water but their
salts are freely soluble.
• . However, they are soluble in non polar solvents such as ether or
chloroform.
• Most of the alkaloids are crystalline solids with definite melting point,
some of them are amorphous and few are liquids.
• They are generally colorless compounds but few are coloured
substances e.g. berberine (yellow) betaine (red) etc.
• They are generally bitter in taste and optically active

5. NOMENCLATURE
• The system of nomenclature of alkaloids is similar to that of other
natural products such as flavonoids and terpenoids.
• To One of the major reasons is the vast number of different skeletal
types.
• In most cases alkaloids are denoted by trivial names, which are
derived from the (systematic) botanical name of the source plant.
• The compound name is derived either from the genus name (e.g.,
papaverine is isolated from different Papaver spp.) or the species
name (harmaline is isolated from Peganum harmala).

6. • Some exceptions include pelletierine (referring to the name of the
famous alkaloid chemist Pierre Joseph Pelletier), mor- phine (referring
to the main physiological effect of an alkaloid; the Latin deity of
dreams was Morpheus), and emetine (from Greek emetikos, “an
emetic”).
• A common feature of nearly all alkaloid names is the ending “-ine”
(English, French) or “-in” (German).
• In the case of several different alkaloids occurring in the same plant,
the suffixes “-idine,” “-anine,” “-aline,” “-inine,” and so on are added
to the common principal form

7. PHYSIOLOGICAL ACTION
• Alkaloids are capable to exhibit extensive and well marked pharmacological activities
like:
• Analgesic (cocain, morphine, codeine)
• Antihypertensive (reserpine, deserpine)
• Antimalarial (quinine, cinchonine)
• Antitumor (vinblastine)

8. • Antitussive (codeine, noscapine) Cardiac depressant (quinidine)
• Oxytocic (ergometrine, ergotamine)
• Diuretic (theobromine)
• Smooth muscle relaxant (theophylline)

9. • Tomatin the major alkaloid of tomato acts as a repellent.
• They also acts as regulatory growth factors and, reserve substances
for nitrogen and other elemental supply.
• They occur as pigments, such as pteridine and betalains and attract
animals for pollination.

10. OCCURENCE
• Alkaloids
• There are more than 6000 have been isotopol
• Most of hem occass in the plant kingdom, ~1% in animally and less
than 0.5%. From boologia and fun guy.
• eg: coccinelline Animal Cocinella

11. • In plan kingdom angiospere were found to have longe no of know
alkaloids than gymnosperme. and premidophytes.
• 1 paparanaca in which all Spelier contains aukaloid.
• Alsacial may occur at duittrent pack of the plant like leaves. I reik.
root.skem seedere
• in some cases p-somniterum, A. boldo cukaloby were isolated From
all part of he plant.

12. ISOLATION
• Alkaloids containing a quaternary nitrogen atom remain saltlike in the
basic aqueous solution. They can be isolated by precipitation as
water-insoluble salts such as picrates (with picric acid)
• or as Reineckates (with ammonium Reineckate) followed by
displacement of the complex anion to chloride (e.g., through ion
exchange). An example of a quaternary alka- loid is toxiferine
dichloride from Calebash curare.

13. • In plants, alkaloids usually occur as salts of common plant acids.
• The powdered drug is treated several times with a mixture of
methanol and acetic acid, transforming the salts to alkaloid
hydroacetates, which are soluble in methanol. The combined filtrates
are evaporated, and the residue is taken up in 1% hydrochloric acid.
• Chlorophyll and other neutral or acidic compounds and neutral alka-
loids can be extracted with an organic solvent such as ether or
methylene chloride.
• The remaining acid solution is rendered basic with potassium
carbonate, liberating the free alkaloids, which can be extracted with
other or methylene chloride to yield the crude alkaloids

14. THANKS