An extraction and preparati
ve HPLC method has been de
vised to simultaneously purify sulforaphaneand sulforaphane nitrile from the seed of
Brassica oleracea var.
italica c
v. Brigadier. The seed wasdefatted with hexane, dried, and hydrolyzed in deionized water (1:9) for 8 h. The hydrolyzed seedmeal was salted and extracted with methylene chloride. The dried residue was redissol
ved in a 5%acetonitrile solution and washed with excess hexane to remo
ve nonpolar contaminants. The aqueousphase was filtered through a 0.22-
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m cellulose filter and separated by HPLC using a Waters PrepNo
va-Pak HR C-18 re
verse-phase column. Refracti
ve index was used to detect sulforaphane nitrile,and absorbance at 254 nm was used to detect sulforaphane. Peak identification was confirmed usinggas chromatography and electron-impact mass spectrometry. Each kilogram of extracted seed yieldedapproximately 4.8 g of sulforaphane and 3.8 g of sulforaphane nitrile. Standard cur
ves were de
velopedusing the purified compounds to allow quantification of sulforaphane and sulforaphane nitrile inbroccoli tissue using a rapid GC method. The methodology was used to compare sulforaphane andsulforaphane nitrile content of autolyzed samples of se
veral broccoli
varieties.Keywords:
Brassica oleracea; glucosinolates; broccoli; sulforaphane; sulforaphane nitrile; isothiocyanate; HPLC