2.7.2. White Mustard
Synonyms Brassia albaHook f. & Th., Sinapis alba Linn.
Biological Source These are the dried ripe seeds of Brassia alba H.f. & T., belonging to family Cruciferae.
Geographical Source The plant is grown in India as a garden crop. It is a weed usually arising from cultivation in Panjab.
Preparation The powdered white mustard seeds are defatted with a suitable solvent (e.g., petroleum ether, n-hexane) and the dried marc is extracted with boiling ethanol (95% v/v). The thioglycoside is purified by dissolving in warm water, decolourised with activated charcoal, filtered and the resulting filtrate is crystallied out.
Chemical Constituents The main constituent of white mustard is the thioglycoside known as sinalbin (or sinapine glucosinalbate) having the following structure:
The enzymatic hydrolysis of sinalbin by the enzyme myrosin gives rise to one mole each of glucose, acrinyl isothiocynate and sinapine acid sulphate as shown
Chemical Tests
1. The hydrolysed product of sinalbin e.g.; sinapine acid sulphate and other salts are crystalline and give rise to a distinct bright yellow colouration in an alkaline medium .
Uses
The paste of white mustard seed is frequently employed in the form of a plaster or poultice as counter irritants and rubefacients.
