Separation And Identification Of Sulforaphane Hydrolyzed From Glucosinolate In Broccoli Seed

Sulforaphane can be obtained form cruciferous vegetables as one of theproducts of enzymatic or acid hydrolysis of glucoraphanin, which has beenindentified the best anticancer activity. Molecular weight is 177.29, formula isC₆H₁₁S₂NO, structure as follows:In this paper, the hydrolysis condition of glucoraphanin, the extraction,isolation and identification of sulforaphane obtained from broccoli seed werestudied, which established the groundwork for developing sulforaphaneproducts.The effects of solvent, ultrasonic, defatting treatments on the extracting ofsulforaphane in broccoli seed were studied. In order to have maximumsulforaphane content, the optimized extraction processes were as follows: thebroccoli seed were smashed. Then using water to wet the seed meal and left toautohydrolysis at room temperature for 8 hours. Following autohydrolysis, themeal was lyophilized and the dried meal was ultrasonic extracted with acetonefor 60 minute. The crude acetone extract was filter and concentrated in vacuo todark brown oil on a rotary evaporator(30℃). The concentrate was washed with aration of water and centrifugated. The aqueous layer was filtered using 0.22μm film for HPLC detection.The effects of time, temperature, pH, the volume of ascorbic acid and wateron the hydrolysis of glucoraphanin were determinated. The optimum hydrolyticconditions for sulforaphane from glucoraphanin existed in broccoli seed were: 8hours; 25℃; pH=4.0; ascorbic acid: broccoli=0.02 (mg/g); broccoli:Water= 1:2(g/mL).First, glucoraphanin hydrolysis products extracted from broccoli seed wasseparated by silica gel column chromatography. The fractions containingsulforaphane were then purified by Sephadex LH-20 gel chromatography.Follow by preparation of sulforaphane using preparative high-performanceliquid chromatograph (Pre-HPLC). Purity of sulforaphane was 92.8±1.2% whichwas verified using HPLC.The structure of sulforaphane was identificated by GC-MS (Probability94.96%) and NMR spectra.This study is useful for the preparative-scale isolation of sulforaphanehydrolyzed by glucoraphanin in broccoli seed and should faxilitate moreextensive studies into the anticarcinogenic activity of these naturally occurringcompounds.