General Method OF Isolation of Glycoside 

*  Glycoside is a molecule in which a sugar (Glycone part) is attached to a Non-sugar (Aglycone) functional group via a Glycoside bond (O/S/N/C). upon hydrolysis, glycosides are divided into a non – sugar group (which have some pharmacological Action) and a sugar moiety, which don’t have any pharmacological action.

*    Example: Anthraquinone, Coumarin, Flavonoid glycosides.

Isolation 

Sta-otto method 

  • Find me powdered drag containing glycoside is extracted by successive extraction in a soxhlet apparatus with alcohol as solvent. 
  • The thermolabile glycoside should be extracted at below 45 degree Celsius. The extract is treated with lead acetate to precipitate tannins and filtered it.
  • To the filtrate hydrogen sulphide gas is passed, The excess of lead acetate is precipitated as lead sulphide.
  • Pure component is determined by the spectroscopy method.

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