Alkaloids

Question 1

Importance of alkaloids

Answer 1

Protective as poisonous agents prevent attack by insects and animals.
•Detoxification of harmful substances
•Regulatory growth factors
•Reserve substances for supply of nitrogen.
•Participates in plant metabolic processes.
•Alternate source of energy eg. Alkaloid glycosides

Question 2

Are alkaloids highly distributed in fungi?

Answer 2

No

They’re rare eg Ergot alkaloid

Question 3

What are some extremely toxic alkaloids

Answer 3

Ergot alkaloids in the middle ages in Europe
•Coniine from hemlock: execution of Socrates
•Cleopatra and Hyocyamus muticus

Question 4

Free alkaloids are soluble in?

Answer 4

Organic solvents

Question 5

Alkaloid salts soluble in?

Answer 5

Acqueous solvents

Question 6

What is dragendorff’s reagent and what color change is seen

Answer 6

Brown color / orange

Reagent is Potassium bismuth iodide- KBI

Question 7

What is reagent for Mayer’s test and color change

Answer 7

Potassium mercuric iodide
KMI

Buff/Creamy or pale yellow ppt

Question 8

Wagners reagent and color change

Answer 8

Yellow ppt

Potassium Iodide

Question 9

What does nor in numenclature mean

Answer 9

indicates N -demethylation

Eg norepinephrine means epinephrine without CH3 group

Question 10

What does dine in numenclature mean

Answer 10

dine’-denotes a type of isomer
•Quinine and quinidine-epimers
•Cinchonine and cinchonidine

Question 11

derived from amino acids and have nitrogen in a heterocyclic ring system

Answer 11

True alkaloids

Question 12

not derived from amino acids but have nitrogen in a heterocyclic system.

Answer 12

Pseudoalkaloids

Question 13

derived from amino acids but nitrogen is not in a heterocyclic system. Also atypical alkaloids.

Answer 13

Proto-alkaloids:

Question 14

What is non heterocyclic alkaloids and egs

Answer 14

Nitrogen doesn’t form part of heterocyclic ring.

Found in Atypical, Protoalkaloids. Biological Amines

Question 15

Plant sources of non heterocyclic alkaloids

Answer 15

1.Peyote or Mescal Button
cactus Lophophora williamsii
CACTACEAE
Active constituent: Mescaline

2. Ephedra

• Ephedra spp. EPHEDRACEAE
• Contains 0.5 – 2% alkaloids including Ephedrine and Pseudoephedrine.
• Ephedrine – brochodilator for asthma high fever related.

3. Colchicine
   •Colchicine: From Colchicum autumnale (colchicaceae)
   •For the treatment of gout
   •Taxol (Paclitaxel): from Taxus brevifolia (Taxaceae)
   •Anticancer drug

Question 16

•Structurally these have the nitrogen as part of a cyclic ring system.
Have 11 groups

Answer 16

Heterocyclic

Question 17

Botanical source of quinolines

Answer 17

dried bark of Cinchona succirubra (Rubiaceae)

Constituents include Quinine, quinidine, cinchonine, cinchonidine

Question 18

What are apophine alkaloids

Answer 18

Reduced isoquinolines/ naphthalene

Eg. BOLDINE

Question 19

examples of isoquinolines

Answer 19

Morphine
Narcotine
Codeine

Question 20

Examples of quinolizidine

Answer 20

Cytisine

Sparteine

Question 21

Examples of indole alkaloids

Answer 21

Ergometrine
Vinblastine
Vincristine
Erhotamine
Serpentine

Question 22

Egs of indolizidine

Answer 22

Castanospermine

Swainsonine

Question 23

Egs of imidazole

Answer 23

Pilocarpine
Pilosine

Pilolo

Question 24

Egs of tropane alkaloids

Answer 24

Hyoscine
Cocaine
Atropine

Question 25

What alkaloid is found in belladonna It’s botanical source And uses

Answer 25

Tropane alkaloid; hyoscine Leaves of Atropa belladonna of the family Solanaceae Used as tinctures for preparing sedatives and to check secretions Mist mag trisilicate has belladonna

Question 26

What alkaloids are in coca | Botanical source

Answer 26

Cocaine ,cinnamylcocaine and alpha-truxilline. leaves of Erythroxylum coca or E. truxillense

Question 27

What are purine bases Egs of alkaloids Egs of compounds

Answer 27

A fusion of Pyrimidine and imidazole Important compounds are –Caffeine –Theobromine –Theophylline Alkaloids are Adenine, guanine and xanthine

Question 28

Reagent for murexide test and color

Answer 28

Potassium Chlorate in conc HCL exposed to NH3 vapour Purple color gives +ve test

Question 29

Egs if the few alkaloids that are liquid

Answer 29

Coniine and nicotine

Question 30

Eg of alkaloid that is coloured

Answer 30

Berberine- green

Question 31

Physical properties of alkaloids

Answer 31

* Are solids * Few are liquids eg coniine and nicotine * Few are coloured eg. Berberine * Free bases soluble in organic solvent * Alkaloidal salts soluble in aqueous solvent * Generally bitter with marked biological activity

Question 32

Chemical property of alkaloid

Answer 32

Basisity Due to unshared electron pairs in the nitrogen atom