1. 1. Vinca
2. Rauwolfia
3. Belladonna
4. Opium
By-Maninderjit kaur
Rayat-Bahra Institute of Pharmacy, Hoshiarpur

2.  The term “alkaloid” (alkali-like) is commonly used to
designate basic heterocyclic nitrogenous compounds of plant
origin that are physiologically active and generally possessing
a marked physiological action on man or animals even in small
quantities
 The nitrogen is usually contained in a heterocyclic ring system
and it mainly derived from amino acids

4. CLASSIFICATION
 There are three main types of alkaloids:
(1) True alkaloids
(2) protoalkaloids and
(3) pseudoalkaloids.
 True alkaloids and protoalkaloids are derived from
amino acids,
 whereas pseudoalkaloids are not derived from these
compounds.

5.  True alkaloids derive from amino acid and they share a
heterocyclic ring with nitrogen.
 These alkaloids are highly reactive substances with biological
activity even in low doses.
 All true alkaloids have a bitter taste and appear as a white solid,
with the exception of nicotine which has a brown liquid.
 True alkaloids form water-soluble salts.
 Moreover, most of them are well-defined crystalline substances
which unite with acids to form salts.
 True alkaloids may occur in plants (1) in the free state (2) as
salts and (3) as N-oxides. Examples of true alkaloids include
such biologically active alkaloids as cocaine, quinine, dopamine
and morphine.

6. Protoalkaloids or Biological amines
 Protoalkaloids are compounds, in which the N atom derived from an amino acid
is not a part of the heterocyclic ring system. Nitrogen is present in side chain eg
Ephedrine, mescaline and yohimbine
 Such kinds of alkaloid include compounds derived from L-tyrosine and L-
tryptophan.
Pseudoalkaloids
 Pseudoalkaloids are compounds, the basic carbon skeletons of which are not
derived from amino acids.
 These are not derived from amino acids but have nitrogen in a heterocyclic ring.
 These alkaloids can also be derived from nonamino acid precursors. The N atom
is inserted into the molecule at a relatively late stage, for example, in the case of
steroidal or terpenoid skeletons.
 Examples of pseudoalkaloids include such compounds as caffeine and theobromine,
chlorogenic acid

7. QUALITATIVE CHEMICAL TESTS FOR ALKALOIDS
General tests answered by all alkaloids are as follows:
 Dragendorff’s Test
 Drug solution + Dragendroff’s reagent (Potassium Bismuth Iodide),
formation of Orange red colour
 Mayer’s Test
 Drug solution + few drops of Mayer’s reagent (potassium mercuric iodide),
formation of creamy-white precipitate
 Hager’s Test
 Drug solution + few drops of Hagers reagent (Saturated aq. Solution of
Picric acid), formation of crystalline yellow precipitate
 Wagner’s Test
 Drug solution + few drops of Wagner’s reagent (dilute Iodine solution),
formulation of reddish-brown precipitate
 Tannic Acid Test
 Drug solution + few drops of tannic acid solution, formation of buff
coloured precipitate

8. Physical Properties:
 I- State:
◦ Most alkaloids are crystalline solids.
◦ Few alkaloids are amorphous solids e.g. opium
◦ Some are liquids that are either:
Volatile e.g. nicotine and coniine, or
 Non-volatile e.g. pilocarpine and hyoscine.
 II- Color:
 The majority of alkaloids are colorless but some are
colored e.g.:
◦ Colchicine and berberine are yellow.
◦ betanidine is orange.
 The salts of sanguinarine are copper-red

9.  III- Solubility:
 Both alkaloidal bases and their salts are soluble in
alcohol.
 Generally, the bases are soluble in organic solvents and
insoluble in water
 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 are usually soluble in water and, insoluble or
sparingly soluble in organic solvents.
 Exceptions:
 Salts insoluble in water: quinine monosulphate.
 Salts soluble in organic solvents: lobeline and apoatropine
hydrochlorides are soluble in chloroform

10.  IV- Isomerization:
 Optically active isomers may show different physiological
activities. l-ephedrine is 3.5 times more active than
d-ephedrine.
 l-ergotamine is 3-4 times more active than d-ergotamine.
 d- Tubocurarine is more active than the corresponding l- form.
 Quinine (l-form) is antimalarial and its d- isomer quinidine is
antiarrythmic.
 The racemic (optically inactive) dl-atropine is physiologically
active.

11. Chemical Properties
 Most of the alkaloids are basic in nature, due to the availability of
lone pair of electrons on nitrogen.
 The basic character of the alkaloid compound 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 electron.
 Their salt formation with an inorganic acid prevents many a time their
decomposition.
 In the natural form, the alkaloids exist either in Free State, as amine or
as salt with acid or alkaloid N-oxides.

12. N
N
NN
H
N
H
N
NH
Me
N
Tropane
N
H
N
N N
NH
Piperidine Pyridine Pyrrolidine Quinoline
Isoquinoline PurineImidazoleIndole
NH
Tetrahydro-
isoquinoline

13. ◦ Narcotic analgesic e.g.Morphine
◦ Antimalarial e.g. Quinine
◦ Reflux excitability e.g.Strychnine
◦ Respiratory stimulant e.g.Lobeline
◦ Neuralgia e.g. Aconitine
◦ Oxytocic e.g. Erogotometrine
◦ Bronchodilator e.g. Ephedrine, vasicine
◦ Anticholinergic e.g. Atropine
◦ CNS stimulant e.g. Caffeine
◦ Antitussive e.g. Codeine
◦ Antiarrythmic e.g.Quinidine
◦ Antihypertensive e.g. Reserpine
◦ Anticancer e.g. Vincristine
◦ Antiglucoma e.g. Pilocarpine


14.  Synonyms: Vinca rosea, Catharanthus, Madagascar periwinkle
 Biological Source
 Vinca is the dried entire plant of Catharanthus roseus Linn., belonging
to family Apocynaceae.
C.C. The important alkaloids in Catharanthus are the dimer indole
indoline alkaloids Vinblastine and Vincristine and they possess definite
anticancer activity. Vindoline and Catharanthine are indole monomeric
alkaloids. It also contains monoterpenes, sesquiterpene, indole and
indoline glycoside.
 Use:It's cytotoxic used for hodgkins and non hodgkins disease.
 Vinblastin is an antitumour alkaloid used in the treatment of Hodgkin’s
disease.
 Vincristine is a cytotoxic compound and used to treat leukaemia in
children.
Anticancer single or combination therapy.
M.O.A: bind to protein (tubulin) which inhibits mitosis in
microtubules.

16.  Synonyms
 Sarpagandha, Chandrika; Chootachand; Indian snake root.
 Biological Source
 Rauwolfia consists of dried roots of Rauwolfia serpentina Benth.,
belonging to family Apocynaceae.
 Chemical Constituents: It contains about 0.7–2.4% total
alkaloidal bases from which more than 80 alkaloids have been
isolated. The prominent alkaloids isolated from the drug are
reserpine, rescinnamine, ψ-reserpine, rescidine, raubescine and
deserpidine.
 The other alkaloidal components are ajmalinine, ajmaline,
ajmalicine (8-yohimbine), serpentine, serpentinine,
tetrahydroreserpine, raubasine, reserpinine, isoajamaline and
yohambinine.

17.  Uses
 Rauwolfia in used as hypnotic, sedative and
antihypertensive.
 It is specific for insanity, reduces blood pressure and
cures pain due to affections of the bowels.
 It is given in labours to increase uterine contractions
and in certain neuropsychiatric disorders.
 Ajmaline, which has pharmacological properties
similar to those of quinidine, is marketed in Japan for
the treatment of cardiac arrhythmias.

18.  Marketed Products
 It is one of the ingredients of the preparations known as
Confido, Lukol, Serpina (Himalaya Drug Company)
and Sarpagandhan bati (Baidyanath).

19.  Synonyms
 Belladonna herb; Belladonna leaf; Deadly night shade leaves; Banewort;
Death’s herb, Dwale; Poison black cherry; Folia belladonnae.
 Biological Source
 Belladonna consists of dried leaves and flowering tops of Atropa
belladonna Linn. (European Belladonna), belonging to family Solanaceae.
It contains about 0.35% of total alkaloids calculated as hyoscyamine.
• Main Alkaloids are:
 1- Atropine.
 2- Hyoscyamine.
 3. Hyoscine (Scopolamine).
 Hyoscyamine is the major natural alkaloid with negative optical rotation (l-
form).
 During extraction hyoscyamine racemizes to the optically inactive dl
Atropine.
 Both alkaloids composed of tropine base and tropic acid

20.  Uses
 The drug is used as adjunctive therapy in the treatment of
peptic ulcer;
 functional digestive disorders, including spastic, mucous and
ulcerative colitis; diarrhoea, and pancreatitis.
 Due to anticholinergic property, it is used to control excess
motor activity of the gastrointestinal tract and spasm of the
urinary tract.
 Decrease motility of smooth muscles so used as
antispasmodics.
 Consumption of Belladonna checks excessive perspiration of
patients suffering from tuberculosis.
 Belladonna acts as a parasympathetic depressant.
 Marketed Products
 It is one of the ingredients of the preparation known as Belladona
plaster (Surgi Pharma) for backache, stiffness of muscles and boil,
swollen joints.

21.  Synonyms: Crude Opium; Raw Opium; Gum Opium; Afim; Post.
 Biological Source: Opium is the air dried milky latex obtained by incision
from the unripe capsules of Papaver somniferum Linn, or its variety P.
album Decand., belonging to family Papaveraceae.
 Opium is required to contain not less than 10% of morphine and not less
than 2.0% of codeine. The thebaine content is limited to 3%.
C.C: The alkaloids are combined with meconic acid.
The other alkaloids isolated from the drug are codeine (0.8–2.5%), narcotine,
thebaine (0.5–2%). noscapine (4–8%), narceine and papaverine (0.5–
2.5%). Morphine contains a phenanthrene nucleus
The drug also contains sugars, sulphates, albuminous compounds, colouring
matter and moisture.

22.  Uses
 Opium and morphine have narcotic, analgesic and sedative
action and used to relieve pain, diarrhoea dysentery and
cough.
 Poppy capsules are astringent, somniferous, soporific, sedative
and narcotic and used as anodyne and emollient.
 Codeine is mild sedative and is employed in cough mixtures.
Noscapine is not narcotic and has cough suppressant action
acting as a central antitussive drug.
 Papaverine has smooth muscle relaxant action and is used to
cure muscle spasms.
 Opium, morphine and the diacetyl derivative heroin, cause
drug addiction.

23. Codeine MorphineHeroine
Pappaverine Noscapine
(Narcotine)
Thebaine:
6-methoxy codeine