Table of Contents
Resins: curcumin and podophyllotoxin
Resins
Resins are semi-solid, amorphous product delivered from natural living sources and mostly from the plant origin. They are mixture of essential oils, oxygenated products of terpene and carboxylic acids found in exudation from the trunk of various trees. They are transparent and translucent solids, semi solids or liquid substance containing larger number of carbon atoms.
Properties of resins
1. Resins can be in the form of liquid, semisolid or solid. They often have a sticky consistency.
2. Resins are insoluble in water but soluble in organic solvents.
3. Resins can be resistant to chemicals and corrosion.
4. These are translucent or transparent solid and liquid.
5. Most of the resins are heavier than water.
Uses of resins
1. It is used in the manufacture of adhesive and glues.
2. It is used to create protective coatings for surfaces such as paint and varnish.
3. It is used for casting and molding.
4. It is used for various dental applications include dental filing and crowns.
5. It is used as anti-viral agent.
6. It is also used in antitumor agents.
Curcumin
Curcumin or curcuminoids are the diarylheptanoid compounds obtained from the dried rhizomes of Turmeric curcuma longa. Family of curcumin is Zingiberaceae. Curcuminoid is the major colouring principle. It is an orange yellow, crystalline powder. Basically, curcumin is insoluble in water but soluble in alcohol.
Isolation of curcumin
1. Turmeric powder is extracted with 95% alcohol in Soxhlet apparatus.
2. Extract is filter and concentrated to semisolid residue.
3. Now, this semisolid residue is dissolved in sufficient quantity is benzene.
4. Then, add 0.1% NaOH solution, Shaked slowly then alkali layer is separated.
5. Acidity with HCl, yellow color ppt is formed.
6. Extract is concentrated with continuous stirring.
7. Lumpy mass of resin will be separated out.
8. The extract is filtered and evaporate the filtrate to get crystal of pure curcumin.
Analysis by TLC
Sample preparation: 1mg of curcumin is dissolved in 1ml of methanol.
Standard sample: curcuminoid
Stationary phase: Silica gel-G
Mobile phase – chloroform : ethanol : glacial acetic acid (94:5:1)
Detecting agent: observed under UV light at 366nm.
Rf value: 0.79
Podophyllotoxin
It is the lactone resin present in the root and rhizome of podophyllum hexandrum, belonging to family Berberidaceae. It is used as anti-cancer agent.
Isolation of podophyllotoxin
1. Take the weight quantity of rhizomes or roots of podophyllum hexandrum with methanol.
2. Then filter & evaporate to semisolid mass.
3. Dissolve semisolid mass into acidic water. Precipitate is formed which should be allowed for at least for two hours.
4. Filter and wash filtrate with cold water then collect the residue wash with acidified water and dry to obtain dark brown amorphous powder.
5. Extract the residue with hot alcohol then filter and evaporate to dryness.
6. Then, re-crystallise the residue in benzene to yield podophyllotoxin.
Analysis by TLC
Sample preparation: 1mg of podophyllotoxin is dissolved in 1ml of ethanol.
Standard sample: podophyllotoxin
Stationary phase: silica gel-G
Mobile phase: Toluene : ethyl acetate (5:7)
Detecting agents: spray with 50% sulphuric acid heated at 120°C for 10 minutes.
Rf value: 0.39 with violet color.