Alkaloids Flashcards
Importance of alkaloids
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
Are alkaloids highly distributed in fungi?
No
They’re rare eg Ergot alkaloid
What are some extremely toxic alkaloids
Ergot alkaloids in the middle ages in Europe
•Coniine from hemlock: execution of Socrates
•Cleopatra and Hyocyamus muticus
Free alkaloids are soluble in?
Organic solvents
Alkaloid salts soluble in?
Acqueous solvents
What is dragendorff’s reagent and what color change is seen
Brown color / orange
Reagent is Potassium bismuth iodide- KBI
What is reagent for Mayer’s test and color change
Potassium mercuric iodide
KMI
Buff/Creamy or pale yellow ppt
Wagners reagent and color change
Yellow ppt
Potassium Iodide
What does nor in numenclature mean
indicates N -demethylation
Eg norepinephrine means epinephrine without CH3 group
What does dine in numenclature mean
dine’-denotes a type of isomer
•Quinine and quinidine-epimers
•Cinchonine and cinchonidine
derived from amino acids and have nitrogen in a heterocyclic ring system
True alkaloids
not derived from amino acids but have nitrogen in a heterocyclic system.
Pseudoalkaloids
derived from amino acids but nitrogen is not in a heterocyclic system. Also atypical alkaloids.
Proto-alkaloids:
What is non heterocyclic alkaloids and egs
Nitrogen doesn’t form part of heterocyclic ring.
Found in Atypical, Protoalkaloids. Biological Amines
Plant sources of non heterocyclic alkaloids
1.Peyote or Mescal Button
cactus Lophophora williamsii
CACTACEAE
Active constituent: Mescaline
- Ephedra
- Ephedra spp. EPHEDRACEAE
- Contains 0.5 – 2% alkaloids including Ephedrine and Pseudoephedrine.
- Ephedrine – brochodilator for asthma high fever related.
- Colchicine
•Colchicine: From Colchicum autumnale (colchicaceae)
•For the treatment of gout
•Taxol (Paclitaxel): from Taxus brevifolia (Taxaceae)
•Anticancer drug
•Structurally these have the nitrogen as part of a cyclic ring system.
Have 11 groups
Heterocyclic
Botanical source of quinolines
dried bark of Cinchona succirubra (Rubiaceae)
Constituents include Quinine, quinidine, cinchonine, cinchonidine
What are apophine alkaloids
Reduced isoquinolines/ naphthalene
Eg. BOLDINE
examples of isoquinolines
Morphine
Narcotine
Codeine
Examples of quinolizidine
Cytisine
Sparteine
Examples of indole alkaloids
Ergometrine Vinblastine Vincristine Erhotamine Serpentine
Egs of indolizidine
Castanospermine
Swainsonine
Egs of imidazole
Pilocarpine
Pilosine
Pilolo
Egs of tropane alkaloids
Hyoscine
Cocaine
Atropine
What alkaloid is found in belladonna
It’s botanical source
And uses
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
What alkaloids are in coca
Botanical source
Cocaine ,cinnamylcocaine and alpha-truxilline.
leaves of Erythroxylum coca or E. truxillense
What are purine bases
Egs of alkaloids
Egs of compounds
A fusion of Pyrimidine and imidazole
Important compounds are
–Caffeine
–Theobromine
–Theophylline
Alkaloids are Adenine, guanine and xanthine
Reagent for murexide test and color
Potassium Chlorate in conc HCL exposed to NH3 vapour
Purple color gives +ve test
Egs if the few alkaloids that are liquid
Coniine and nicotine
Eg of alkaloid that is coloured
Berberine- green
Physical properties of alkaloids
- 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
Chemical property of alkaloid
Basisity
Due to unshared electron pairs in the nitrogen atom
