Detailed study of Resins including its Definition, properties, types, classification, isolation/extraction

1. RESINS: Definition, classification,
properties and test for identification

2. DEFINITION
• Resins are solid or semi-solid, amorphous products
derived from natural living sources and are mostly
from the plant origin (exception is shellac that is
obtained from the secretions of insect).
• Resins are secondary metabolites produced by
higher plants and are oxidative products of
terpenes.
• Obtained as exudates from plants and considered
as end product of metabolism
• Resins are produced and stored in the schizogenous
glands or cavities of the plants.

3. PROPERTIES:
• These are more or less solid, hard, transparent,
or translucent materials which come in market
as an unorganized drug.
• Soften and melt on heating.
• Resins are insoluble in most polar and nonpolar
solvents like water and petroleum ether, but
dissolve completely in alcohol, solvent ether,
benzene, or chloroform.

4. TYPES:
1. Normal or physiological resin: resins that are
pre-formed in the plants and making injury to the
plants can increase their yield (Example: resin of
Pinus)
2. Abnormal or pathological resin: resins that are
found in the plants Only when injury or incision is
made (Examples: benzoin, Tolu balsam)

5. CLASSIFICATION:
1. On the basis of their formation
2. On the basis of their chemical nature
3. On the basis of occurrence with other secondary
metabolites.
1. On the basis of their formation :
1. Physiological resins – these are formed as a normal
product of metabolism without making injury to the
plants
2. Pathological Resins – formed as a result of wound,
injury or abnormal circumstances (benzoin, colophony,
balsams, aloe resin etc.)

6. 2. On the basis of their chemical nature:
1. Resin acids – resinolic acids
2. Ester resins
3. Resin alcohols – resinols
4. Resin phenols – resinotannols
5. Resenes
1. Resin Acids:
• Resin acids are the carboxylic acid group containing resinous
substances.
• They are soluble in aqueous solution of alkalies producing frothy
solution.
• Examples: Colophony and myrrh (abietic acid and commiphoric
acid) .

7. 2. Resin Esters: This group contains esters as the
chief constituents of the resins
Examples Benzoin and Storax , Benzoin contains
benzyl benzoate, Storax contains cinnamyl
cinnamate
3. Resin Alcohols: They occurs as in free state or
as esters. Example – Balsam of peru with perru
resino tannol.

8. 4. Resin Phenols:
• Resin phenols or resinotannols are also high
molecular weight compounds which occur in free
states or as esters.
• The resinotannol are found in balsam of Peru as
peruresinotannol, in Tolu balsam as
toluresinotannol and in benzoin as
siaresinotannols.
5. Resenes: Chemically inert resin products are
generally termed as resenes. They are generally
found in free state and never form esters or other
derivatives. Asafoetida is an example of resene-
containing drug.

9. 3. On the basis of occurrence with other secondary
metabolites.
1. Oleoresins – naturally occurring mixtures of a
volatile oil and a resin
2. Gum resins – resin associated with gum
3. Oleo-gum resins – a naturally occurring mix of
volatile oil, gums/mucilagenous compound with a
resin
4. Glycoresins – resins in combination with sugar
compounds via Glycosidal linkages
5. Balsams – resins in combination with benzoic or
cinnamic acid either free or combined

10. 1. Oleoresins: Oleoresins are the homogenous mixture of
resin with volatile oils. The oleoresins posses an essence
due to volatile oils. Examples: ginger.
2. Gum Resins: Gum resins are the naturally occurring
mixture of resins with gums. Examples: Colophony
3. Glucoresins: Resins sometimes get combined with
sugars. Example: Jalap
4. Oleo-gum Resins. Oleogum resins are the naturally
occurring mixtures of resin, volatile oil, and gum. The
example includes myrrh and asafoetida

11. 5. Balsams: Balsams are the naturally occurring
resinous mixtures which contain a high proportion
of aromatic balsamic acids such as benzoic acid,
cinnamic acid, and their esters.
Examples: balsam of Peru, balsam of Tolu,
benzoin, and storax.

12. ISOLATION
1. By extracting the drug with alcohol and
precipitating resins present in concentrated
extract by addition of large proportion of water
(e.g. Jalap,Podophyllum).
2. By distillation for separation of oils (e.g.
Colophony)
3. By heating the plant parts (e.g. Guacum)
4. As plant exudates by making incision (e.g.
Myrrh, Asafoetida, Balsams)
5. By processing the incrustations* (e.g. Shellac)

13. METHODS OF EXTRACTION/ ISOLATION:
• 1. Method – A
Powdered drug
Extract the resin with alcohol
Filter
Concentrate
Concentrate the extract with excess of water, shake
Resins get precipitate

14. 2. Method – B
• Powdered drug containing oleo-resin,
• percolate the powdered drug with non-polar
solvent (e.g. acetone, chloroform)
• Extract
• Steam distillation
• Oleo-resin Volatile oils

15. CHEMICAL TESTS:
• 1. HCl TEST: Formation of pink color Presence of resins
• 2. FeCl3 TEST: Greenish blue color Presence of resins
APPLICATIONS:
1. Resins are local irritant and hence act as local cathartics.
e.g. Jalap.
2. As anti cancer (Eg: Podophyllum)
3. In bronchial asthma (e.g. Cannabis)
4. Used externally as mild antiseptic in the form of
tinctures (Benzoin), ointment and plasters (Turpentine and
Colophony)