Pharma Education Network

Glycosides Classification - Their Properties and Examples

Glycosides Classification - Their Properties and Examples

GLYCOSIDES CLASSIFICATION - The drugs containing glycosides encompass within them a large family of plant kingdom and therefore, need to be categorized on different basis they lie in, such as the following:

Glycosides classification On the basis of GLYCONE LINKAGES PRESENT

C-LINKAGE

Those glycosides in which the glycone moiety is attached with the aglycone moiety with the help of carbon atom, are known the C-linkage glycosides.
Properties: these glycosides do not hydrolyse by heating with dilute alkalies.
Examples: aloe vera, cochenial.

O-LINKAGE

Those glycosides in which the glycone moiety is attached with the aglycone moiety with the help of carbon atom, are known the O-linkage glycosides.
Properties: these undergo hydrolysis by treating with acid alkali into aglycone and sugar.
Examples: senna, rhubarb.

S-LINKAGE

Those glycosides in which the glycone moiety is attached with the aglycone moiety with the help of carbon atom, are known the S-linkage glycosides.
Examples: black mustard

N-LINKAGE

Those glycosides in which the glycone moiety is attached with the aglycone moiety with the help of carbon atom, are known the N-linkage glycosides.
Examples: blue berry, black berry.

Glycosides classifiction on the basis STEREOCHEMISTRY

These are based on the type of isomer present, whether it is a cis or trans moiety.
1. cis-α-methyl glycosides
2. trans-β-methyl glycosides

Glycosides classification on the basis of NATURE OF AGLYCONE MOEITY

ANTHRACENE GLYCOSIDES

The glycosides which contain enormous kinds of aglycone moieties such as anthraquinone, anthranol, anthranone, oxanthranone, dianthranone, dianthranol are known as anthracene glycosides.
Identification tests: Bontragor’s test, Modified Bontragor’s test.
Examples: senna, aloe, cascara, cochineal,etc.

CARDIAC GLYCOSIDES

The glycosides which possess a steroidal ring within their aglycone moiety are known as cardiac glycosides. These are further subdivided into two categories based on their aglycone rings, namely,

1. Cardenoliods (C-23)

These are the Cardiac glycosides containing a 5-membered lactone ring. The lactones of cardenoloids contain only 1 double bond attached to the steroidal nucleus through C-17 position.

2. Bufadenoloids (C-24)

These are the Cardiac glycosides containing a 6-membered ring. The lactones of bufadenoloids contain only 2 double bonds attached to the steroidal nucleus through C-17 position.
Medicinal use: used to strengthen the weaken heart and help enhance its working efficiency.
Identification tests: Keller Killani test.
Examples: digitalis, squill, thevetia.

SAPONIN GLYCOSISDES

The glycosides which contain such an aglycone moiety which has a soap-like action and produces haemolysis of RBCs are known as saponin glycosides. These are further subdivide into two categories, namely,
1. Steroidal saponins
2. Pentacyclic Triterpenoid saponins
Properties:
1. The aglycone part is termed as sapogenin.
2. Saponins are bitter and acrid in taste.
Medicinal uses: used as expectorants, demulcents, stress relievers, anti-inflammatory agents, anti-arthiritic agents.
Identification tests: haemolysis test and foam test.
Examples: liquorice, gokhru, brahmi.

ISOTHIOCYNATE GLYCOSIDES

The glycosisdes containing a CSN-linkage as their aglycone moiety are known as isothiocynate glycosides.
Medicinal uses: used as counter-irritant, rubefacient, emetics.
Examples: black mustard.

FLAVANOL GLYCOSISDES

The glycosides where the aglycone part contains flavones and flavanols are called flavanol glycosides.
Properties:
1. These are water soluble in nature.
2. These possess scavenging properties.
Medicinal uses: used as anti-oxidants.
Examples: tea, coffee, sillymarin, citrus fruits like lemon and orange, grapes berries.

CYANOGENETIC GLYCOSIDES

The glycosides in which the hydrocyanic acid is present in the aglycone moiety which is derivative of Mendallic acid, are known as cyanogenetic glycosides.
Properties: on hydrolysis, these glycosides produce benzaldehyde and hydrocyanic acid.
Medicinal uses: used as expectorants.
Examples: bitter almond, wild cherry bark.

BITTER GLYCOSIDES

These are so called and known for their charecterstic bitter taste.
Medicinal uses: used as stomachic, tonic, anti-pyretic agent, anti-helmintic agent, anti-diabetic agent)
Examples: chirata, quassia, gymmneva.

STEROIDAL GLYCOSIDES

In these glycosides, the major aglycone moiety possesses a steroidal ring.
Examples: solanum species

ALDEHYDE GLYCOSIDES

In these glycosides, the major aglycone moiety possesses an aldehydic functional group.
Examples: vanilla pods.

PHENOL GLYCOSIDES

In these glycosides, the major aglycone moiety possesses a phenolic functional group.
Medicinal uses: used as diuretics.
Examples: Bearberry.