Sinalbin

Chemicals and reagents were obtained from the following commercial sources (purity in parenthesis): Gluconapin (3but) (84%), glucoerucin (4mtb) (90%), glucobrassicin (I3M) (86%), glucoraphanin (4msb) (89%), glucoiberin (3msp) (98%) and internal standard, sinalbin (99%) were purchased from PhytoLab GmbH & Co. KG (Vestenbergsgreuth, Germany). 4-Hydroxyglucobrassicin (4OHI3M) (95%), 4-methoxyglucobrassicin (4MOI3M) (94%) and neoglucobrassicin (NMOI3M) (97%) were acquired from Phytoplan, Diehm & Neuberger GmbH (Heidelberg, Germany). Acetonitrile and methanol (LC/MS grade solvents) were obtained from Fisher Chemical (Roskilde, Denmark). Water was obtained from a MilliQ purifier (Millipore, MA, USA). Glacial acetic acid was purchased from Merck (Darmstadt, Germany).

All the reagents employed for both extraction and analysis in this study were analytical-grade products obtained from Sigma-Aldrich (St. Louis, MO, USA) and ThermoFisher Scientific Korea (Seoul, Republic of Korea). Among the 17 GSL standards, 6 GSLs including Progoitrin (PRO), EpiProgoitrin (EPI), Glucobrassicanapin (GBN), Glucoiberin (GIB), Glucoraphenin (GRE), and Sinalbin (SNB) were purchased from Phytolab (Martin Baue, KG, Germany) and the remaining 11 GSL were purchased from Phytoplan (Neuenheimer, Heidelberg, Germany). All standards had a purity of ≥98%.

All glucosinolates and phytohormones used in this study is purchased from suppliers. The glucosinolates include sinigrin (allyl glucosinolate, PN#S0156, Tokyo Chemical Industry, Japan), gluconapin (3-butenyl glucosinolate potassium salt, PN#89688, phytolab, U.S.A.), glucoerucin (4-(methylthio)butyl glucosinolate potassium salt, PN#89686, phytolab, U.S.A.), glucoraphanin (4-(methylsulfinyl)butyl glucosinolate potassium salt, PN#89,215, phytolab, U.S.A.), sinalbin (p-hydroxybenzyl glucosinolate potassium salt, PN#89793, phytolab, U.S.A.), glucotropaeolin (benzyl glucosinolate potassium salt, PN#G0397, Tokyo Chemical Industry, Japan), and glucobrassicin (3-indolylmethyl glucosinolate potassium salt, PN#80593, phytolab, U.S.A.). The phytohormones includes IAA (3-indoleacetic acid, PN# I2886, Sigma-Aldrich, U.S.A.), SA (salicylic acid, PN#1901-2150, Showa Chemical Industry, Japan), JA (jasmonic acid, PN#J0004, Tokyo Chemical Industry, Japan), GA (gibberellin A3, PN#G0029, Tokyo Chemical Industry, Japan), ABA ((±)-abscisic acid, PN#A1049, Sigma-Aldrich, U.S.A.).