This document discusses alkaloids, which are nitrogen-containing organic compounds that have pharmacological effects on humans and animals. It defines three types of alkaloids - true alkaloids, protoalkaloids, and pseudoalkaloids - and provides examples of each type. The document also examines two specific alkaloid-containing plants - vinca and belladonna - describing their macroscopic characteristics, chemical constituents, and medicinal uses.

1. ALKALOIDS

2. INTRODUCTION
• The word “alkaloid” was first coined by
the German chemist Carl F. W. Meissner
in 1819, derived from the Arabic name al-
qali, which is associated to the plant from
which soda was first sequestered.
• The mankind has been using alkaloids
for various purposes like poisons,
medicines, poultices, etc.

3. WHAT ARE ALKALOIDS?
• An alkaloid is a nitrogenous organic molecule
that has a pharmacological effect on humans and
animals.
• They are a class of compounds which typically
contain nitrogen and have complex ring
structures.
• They occur naturally in seed bearing plants and
are found in berries, bark, fruit, roots and leaves.

4. TYPES OF ALKALOIDS
• There are three central types of alkaloids:
1. True alkaloids
2. Protoalkaloids
3. Pseudoalkaloids.
(True alkaloids and protoalkaloids are produced from
amino acids, whereas pseudoalkaloids are not
derived from these compounds.)

5. TRUE ALKALOIDS
• This type of alkaloids are obtained from amino acids
and they share a nitrogen-containing heterocyclic
ring.
• They are highly reactive in nature and have potent
biological activity. They form water-soluble salts,
and many of them are crystalline in nature, which
conjugates with acid and forms a salt.
• Almost all true alkaloids are bitter in taste and solid,
except nicotine, which is a brown liquid. Example:
Atropine

6. PROTOALKALOIDS
• This type of alkaloids contains a
nitrogen atom, which is derived from
an amino acid but is not part of the
heterocyclic ring system.
• Example: Ephedrine.

7. PSEUDOALKALOIDS
• The basic carbon skeleton of pseudoalkaloids is
not directly derived from amino acids; instead,
they are connected with amino acid pathways
where they are derived from by amination or
transamination reaction from forerunners or
postcursors of amino acid.
• Example: Caffeine.

9. VINCA
• Synonyms: Catharanthus, Periwinkle
• Biological source: It is the dried whole plant
of Catharanthus roseus, belonging to family
Apocynaceae. It is also known as Vinca rosea.
• Family: Apocynaceae

10. Macroscopic characteristics:
1. Colour: Flowers are either violet, pinkish white, or Carmine red.
2. Odour: Sweetly scented
3. Taste: Bitter
Chemical characteristics:
• The important alkaloids in Catharanthus are the dimer indole indoline
alkaloids. Vindoline and Catharanthine are indole monomeric alkaloids.
• It also contains monoterpenes, sesquiterpene, indole and indoline
glycoside.

11. USES OF VINCA
• Vincristine and vinblastine are used in the
treatment of cancer.
• It is also used in the treatment of Hodgkin
disease and choriocarcinoma
• It also posess hypotensive and antidiabetic
effects.

12. BELLADONNA
Synonyms: Belladonna leaf, belladonnae
folium,deadly night shade leaf.
Biological source: Belladonna herb consist of dried
leaves or the leaves and the other aerial parts of
Atropa belladonna Linn(European belladonna) or
Atropa acuminata Royale ex-Lindley
Family: Solanaceae

13. Macroscopic characteristics:
1.Colour:
• Green to brownish green(leaves)
• Purple to yellowish brown (flowers)
• Green to brown (fruits)
2. Odour: Slight and Characteristics
3. Taste: Bitter and Acrid
Chemical constituents:
The total alkaloidal content of the drug is 0.4 to 1% and varies in
different parts of the land,roots(0.6%), stems (0.05%), leaves (0.4%)

14. USES OF
BELLADONNA
• It is the parasympatholytic drug with
anticholinergic properties.
• Used to reduce secretions of
sweat,saliva,and gastric juice.
• Also used as an antidote in opium and
chloral hydrate poisoning.