Page 113 - phytochemistry I - PharmD Clinical
P. 113
This is overcome by addition of CaCO3. Mild alkalinity may
sometimes produce racemization.
3. Defatting of fat-rich organs (e.g. seeds) before extraction.
4. Extraction using solvent/solvent partition.
5. Lead acetate solution is added to precipitate impurities present
in the drug sample. Filter the solution & pass H2S gas through
filtrate to neutralize excess of lead.
6. Now concentrate the extract to get crude product.
7. Purify the product by using chromatography techniques
Qualitative tests for identification of glycosides:
Depending on the chemical nature of the genin:
1. Cardiac glycosides: Liebermann’s test
Add chloroform and acetic acid t the extract, violet to blue to
green coloration is observed.
2. Anthraquinone glycosides:
• A red color is formed upon addition of alkali.
• Borntrager’s Test: Add benzene and NH3 (10%) to the
extract, a pink, violet or red coloration in ammonical layer is
observed.
3. S-containing glycosides:
Black color is formed after adding silver nitrate.
4. Coumarin glycosides: Add NaOH (10%) to the extract, a
yellow coloration is observed.
5. Flavonoidal glycosides:
A characteristic color reactions with ammonium hydroxide,
fixed alkalis, aluminum chloride, or ferric chloride, according
to their type.
6. Cyanogenetic glycoside: Guignard’s test
۱۱۱
