INTRODUCTION
Resins are amorphous mixtures of essential oils and oxygenated products of terpenes,
transparent or translucent solids, semi solid or liquid substances. They have complex
chemical nature and contains large no of carbon atoms. Resins are insoluble in water and
heavier than water but they are soluble in non polar solvents like benzene or ether, volatile
oils, fixed oils and alcohol. Resins are hard, non conductor of electricity and combustible in
nature.
CLASSIFICATION
Depending upon the type of the constituents:
Resins are of three types:
1. Acid resins examples Colophony contains abietic acid, Copaiba, Myrrh etc
2. Ester resins examples Benzoin
3. Resin alcohols examples Peru balsam
Depending upon combination with other Constituents:
1. Gum resin: Gum resins are in homogenous combination of gum and resin. These are
always associated with small quantities of other substances like bitter principle,
enzymes and volatile oils etc. It may consist of two or more glycosidal acids in various
proportions and contains trace amount of nitrogen e.g. Myrrh.
2. Oleo resin: When resins are in homogenous combination with volatile oils or oily
liquids, are called oleo resin. They are secreted in schizogenous or schizolysigenous
ducts. Ginger, Capsicum, Turpentine oil.
3. Oleo gum resin: These resins are in homogenous combination with volatile oil and
gum. e.g. Asafoetida.
4. Balsam resin: Those oleo resins which contain aromatic acids like benzoic acid or
Cinnamic acid are known as balsam resin e.g. Benzoin.
5. Glycoresin: These are made up of resin along with sugars e.g. Jalap, Ipomoea.
Some resins are complex natural substances not having transpose any specific chemical
property,
CHEMICAL TEST
1. Solubility test: Resin dissolves when treated with organic solvents like alcohol, ether
or chloroform etc.
2. Ignition test: They produces smoky flame upon burning.
3. HCl test: Drug is treated with hydrochloric acid which forms pink colour, ensures the
presence of resins.
4. Ferric chloride test: The greenish blue colour develops when drug is treated with
ferric chloride solution. This indicates the presence of resins.
EXTRACTION AND ISOLATION OF RESINS
Method A:
Powdered drug
Extract the resin with alcohol
Filter
Concentrate
Concentrate extract an excess of water; shake
Resins get precipitated
[I] BENZOIN (click here)
[II] GUGGAL (click here)
[III] GINGER (click here)
[IV] ASAFOETIDA ( click here)
[V] MYRRH (click here)
[VI] COLOPHONY (click here)