The general method of extraction of glycosides is outlined here. The drug containing glycoside is finely powdered and the powder is extracted by continuous hot percolation using soxhlet apparatus with alcohol as solvent.
ISOLATION
Stas-Otto Method
The general method of extraction of glycosides is outlined
here. The drug containing glycoside is finely powdered and the powder is
extracted by continuous hot percolation using soxhlet apparatus with alcohol as
solvent. During this process, various enzymes present in plant parts are also
deactivated due to heating. The thermolabile glycosides, however, should be
extracted at temperature preferably below 45°C. The extract is treated with
lead acetate to pre-cipitate tannins and thus eliminate nonglycosidal
impurities. The excess of lead acetate is precipitated as lead sulphide by
passing hydrogen sulphide gas through solution. The extract is filtered,
concentrated to get crude glycosides. From the crude extract, the glycosides
are obtained in pure form by making use of processes like fractional
solubility, fractional crystallization and chromatographic techniques such as
preparative thin layer and column chromatography.
The characterization of isolated purified compounds is done
by IR, UV, visible, NMR and mass spectrometry and elemental analysis.
TH 2019 - 2024 pharmacy180.com; Developed by Therithal info.