Page 11 - phytochemistry II -pharmD general

Extraction, purification and isolation of alkaloids from powered plant:

For extraction of alkaloids from powered plant we must note that:
1. Alkaloids are basic compounds.
2. Ability of alkaloids to form salts with acids.
3. 3. Alkaloidal salts alkali Alkaloidal bases
4. Solubility of alk. bases in organic solvents.
5. Solubility of alk. salts in H2O.
6. Solubility of both alk. bases & alk. salts in alcohol.

Extraction of alkaloids from powered plant:

➢ Preparation of plants for extraction of alkaloids
➢ Extraction of Alkaloids According to the technique used.
➢ Extraction of Alkaloids According to solvents used.

➢ Preparation of plants for extraction of alkaloids
1.Plant material should be reduced to coarse powder to facilitate penetration of
solvents to cells & tissues-containing alkaloids
2. Defatting of plant material (seeds) with pet. ether (non -polar solvent) which
does not extract alk.

➢ According to the Technique used for extraction of Alkaloids from
powered pants we have:

❖ Maceration.
❖ Continuous cold extraction (Percolator).
❖ Continuous hot extraction (Soxhlet apparatus).

❖ Maceration
The powered plant is soaked in certain solvent for specific time, then filtered and
re-soaked again in fresh solvent, ….. till complete extraction (exhaustion). This
technique is used with heat sensitive alks.

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