A Glycoside is any molecule in which sugar group is bonded through its anomeric carbon to another grp via Glycosidic bond.
A glycosidic bond is a type of chemical bond that joins sugar molecule to another molecule.
The sugar grp is known as glycone and non-sugar grp as aglycone or genin.
The glycone and aglycone portions can be chemically separated by hydrolysis in presence of acid.
The glucose can consist of a single grp or several sugar groups.
2. A Glycoside is any molecule in which sugar group is bonded through
its anomeric carbon to another grp via Glycosidic bond.
A glycosidic bond is a type of chemical bond that joins sugar
molecule to another molecule.
The sugar grp is known as glycone and non-sugar grp as aglycone or
genin.
The glycone and aglycone portions can be chemically separated by
hydrolysis in presence of acid.
The glucose can consist of a single grp or several sugar groups.
3. PROPERTIES
They are crystalline or amorphous substances.
Soluble in water and alcohol whereas insoluble in organic
solvents like benzene and ether.
The aglycone part is soluble in organic solvent.
They are hydrolysed by water, enzymes and mineral acids.
They are optically active.
4. CLASSIFICATION
A) On The Basis Of Glycone :
If glycone grp of glycoside is glucose, then molecule is glucoside.
If it is fructose, then molecule is fructoside.
If it is glucuronic acid, then the molecule is glucuronide, etc.
5. B) On The Basis Of Glycosidic Linkage :
i) O-glycoside :- Sugar molecule is combined with phenol or OH group
of aglycone. Eg- Arbutin, cardiac glycoside, anthraquinone glycoside
like sennosides etc.
ii) N-glycoside :- Sugar molecule is combined with N of –NH (amino
grp) of aglycon. Eg- Nucleosides
iii) S-glycoside :- Sugar molecule is combined with S or –SH (thiol grp)
of aglycon. Eg- Sinigrin
iv) C-glycoside :- Sugar molecule is directly attached with C-atom of
aglycon. Eg- Anthraquinone glycosides like Aloin, Barbaloin,
cascaroside.
6. C) On The Basis Of Aglycone :-
Sr. No CLASS EXAMPLES
1. Anthraquinone Glycosides Senna, Aloe, Rhubarb
2. Sterol or Cardiac Glycosides Digitalis, Squill
3. Saponin Glycosides Dioscorea, Liquorice, Ginseng
4. Cyanogenitic/Cyanophoric Glycosides Bitter almond, Wild cherry bark
5. Thiocynate and Isothiocynate Glycosides Black mustard
6. Flavone Glycosides Ginkgo
7. Aldehyde Glycosides Vanilla
8. Phenol Glycosides Bearberry
9. Steroidal Glycosides Solanum
10. Bitter and miscellaneous Glycosides Gentian, Chirata
7. SENNA
Synonyms : Senna leaf, Cassia senna, Tinnevalley senna
Biological Source : It consists of dried leaflets of Cassia angustifolia or
Cassia senna Vahl belonging to family Leguminosae.
Chemical Constituents : Senna mainly contains anthraquinone
glycosides called as Sennoside A, B, C, D.
Also consist of Rhein 8-glucoside, Rhein 8-diglucoside, 8-glucoside,
kaempferol, isoharmnetin, aloe emodin.
It also contains phytosterol, myricyl alcohol, salicylic acid, resin, etc.
Uses : It is used as purgative in perpetual constipation.
8. ALOE
Synonym : Aloe, Kumari
Biological Source : Aloes is dried or fresh juice of leaves of Aloe
barbadensis Miller, Aloe africana Miller, Aloe spicata Baker, belonging
to family Liliaceae.
Chemical Constituents : Aloe are major sources of anthraquinone
glycosides.
Contains of aloin, barbaloin, aloe-emodin, isobarbaloin, resins.
Uses : Aloes is used as a purgative, treatments of pain and itching. Aloe
gel is used externally in the form of ointments, creams to assist healing
of wounds, burns, eczema, and also in psoriasis.
9. BITTER ALMOND
Synonym : Amygdala amara
Biological Source : Bitter almonds are dried ripe seeds of plants, Prunus
amygdalus, belonging to family Rosaceae.
Chemical Constituents : Bitter almonds contain fixed oil, proteins, enzyme
emulsin and a colourless crystalline bitter glycoside known as amygdalin.
It also consist of volatile oil.
Uses : It is used as sedative. Oil is used in demulcent skin lotion. It is also
used in preparation of amygdalin, bitter almond water, in perfumery and in
the form of liquors.
10. ALKALOIDS
These are organic product of natural or synthetic origin which are
basic in nature and contain one or more nitrogen atoms, normally of
heterocyclic nature, and possess specific physiological actions on
human or animal body when used in small quantities.
Alkaloids are founds as secondary metabolites in plants, animals,
fungi and can be extracted from their sources by treatment with acids.
Most alkaloids have very bitter taste.
11. CLASSIFICATION
A. TRUE ALKALOIDS : They are toxic in nature, contain
heterocyclic nitrogen which is derived from amino acid and are
always basic in nature. They are normally present in plants as salts
of organic acids. Eg. Atropine, Morphine, Nicotine
B. PROTO ALKALOIDS : They are simple amines in which the
nitrogen is not in heterocyclic ring. They are basic in nature and
prepared in plants from amino acids. Eg. Adrenaline, Ephedrine
C. PSEUDO ALKALOIDS : Alkaloids like compounds that do not
originate from amino acids. They do not show many of the typical
characters of alkaloids, but give standard qualitative test for
alkaloids. Eg. Caffeine, Theophylline
12. VINCA
Synonyms : Catharanthus, Periwinkle
Biological Source : It is the dried whole plant of Catharanthus roseus,
belonging to family Apocynaceae.
Chemical Constituents : It consist of indole alkaloids Vincristine,
Vinblastine.
Also contains Ajmalicine, serpentine, tetrahydroalstonine.
Uses : Vincristine sulphate acts as an antineoplastic agent.
Vinca exhibits hypotensive and antidiabetic actions.
It is given intravenously in the treatment of acute leukemia of children.
13. RAUWOLFIA
Synonyms : Sarpgandha, Serpentina root, Rauwolfia root
Biological Source : Rauwolfia consist of dried roots of the plant known
as Rauwolfia serpentina Benth, belonging to family Apocynaceae.
Chemical Constituents : It consist of indole alkaloids. The imp alkaloid
of rauwolfia is reserpine.
Other alkaloids present in drug are ajmaline, ajmalicine, rescinnamine,
yohimbine, serpentine, rauwolfinine, serpentinine.
Uses : It is used as antihypertensive, tranquilliser and also used in
treatment of circulatory diseases.
14. BELLADONA
Synonyms : Deadly night shade leaf, Belladona leaf, Belladona folium
Biological Source : It consist of dried leaves and other aerial part of
Atropa belladona Linn. Or Atropa acuminata Royle ex-Lindley,
belonging to family Solanaceae.
Chemical Constituents : The main alkaloids are L-hyoscyamine,
belladonine, scopoletin, hyoscine, homotropine.
Uses : It is parasympatholytic drug with anticholinergic properties.
It is used to reduce the secretions such as sweat, saliva and gastric
juice.
It is also used as an antidote in opium and chloral hydrate poisoning.
15. OPIUM
Synonyms : Raw opium
Biological Source : It is the dried latex obtained by incision from the
unripe capsules of Papaver somniferum Linn., dried or partly dried by
heat, and worked into somewhat irregularly shaped mases. Poppy
plant belongs to family Papaveraceae.
Chemical Constituents : The latex contains mainly the alkaloids derived
from amino acids tyrosine and phenylalanine
Also contains Morphine, codeine, papaverine, narcotine, narceine.
Uses : Opium belongs to the category of hypnotic, sedative and
analgesic. Codeine relieves local irritation in bronchial tract and as an
antitussive used in various cough medicines.