Page 12 - phytochemistry II -pharmD general

❖ Continuous cold extraction

Continuous cold extraction)
using percolator

Continuous addition of solvent
to the powdered plant and
Receiving the extract
containing alks. till complete

extraction.

used for heat sensitive alks.

❖ Continuous hot extraction (Soxhlet apparatus)
used in case of heat-stable alkaloids.

➢ According to Solvents used for extraction of alkaloids there are three
methods:

1. Using water-immiscible organic solvent e.g. CH3Cl, CH2Cl2, ether …..
2. Using water miscible organic solvent (alcohol).
3. Using dilute aqueous acid (acidulated H2O).

1- Using water-immiscible organic solvents (extract alkaloidal bases)

▪ This method is used to extract the alkaloidal bases from the powered plant.
▪ So, the powered plant must be firstly prepared by liberation of the free base

by addition of suitable alkali.
▪ The alkalinized power is packed in the extraction apparatus and extracted

with the H2O-immiscble organic solvent

The water-immiscible organic solvents used for extraction of alk. bases are
❖ CHCl3 (chloroform)
❖ Ether.
❖ Methylene chloride (CH2Cl2),….

▪ Most alks. are dissolved in CHCl3 except 4ry alk, alk. N-oxide and
morphine

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