Daidzein

Daidzein, daidzin, daidzin 6″-O-acetate, daidzin 6″-O-malonate, genistein, genistin, genistin 6″-O-acetate, genistin 6″-O-malonate, glycitein, glycitin, glycitin 6″-O-acetate, and glycitin 6″-O-malonate were purchased from FUJIFILM Wako Pure Chemical Corp (Osaka, Japan). CMS; dimethyl sulfoxide (DMSO); Gelrite™; indole-3-butyric acid (IBA); ascorbic acid; 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; methyl jasmonate (MJ); and phosphate-buffered saline were purchased from Sigma-Aldrich Co., LLC (St. Louis, MO, USA). Mass-grade formic acid (FA), acetonitrile, methanol, and water were purchased from Thermo Fisher Scientific (Waltham, MA, USA). The other chemicals employed in this study were of American Chemical Society grade or higher. The Sinhwakong soybean variety (an elite cultivar) was supplied by the National Institute of Crop Science (Cheonju, Republic of Korea).

In this study, AB (wild-type), Nrf2-mutant (nfe2l2a^fh318) [13 (link)], and Nrf2-knockout (nfe2l2a^it321) zebrafish larvae were used. Both mutant and knockout lines were maintained by PCR-based genotyping. The former was maintained as described previously [14 (link)]. For the latter, the primer sets 5′-TATTGTGCAGCCCTAGTGTG and 5′-TAGCTGAAGTCGAACACCTC were used. Larvae used in these experiments were obtained from parents of AB, homozygous nfe2l2a^fh318 or homozygous nfe2l2a^it321 by natural mating. The nfe2l2a^fh318 and nfe2l2a^it321 lines can be obtained from the Zebrafish International Resource Center (http://zebrafish.org (accessed on 2022 January 5)) and the National BioResource Project Zebrafish (https://shigen.nig.ac.jp/zebra (accessed on 2022 January 5)), respectively.
Genistein, glycitin, glycitein, daidzin, daidzein, equol, and cinnamaldehyde were purchased from FUJIFILM Wako (Osaka, Japan). Genistin and sulforaphane were purchased from NAGARA Science (Gifu, Japan) and LKT Laboratories (St. Paul, MN, USA), respectively. For stock solutions, hydrogen peroxide and sodium arsenite were dissolved in MilliQ water (Merck-Millipore Billerica, MA, USA), sulforaphane in ethanol, and isoflavone compounds in dimethyl sulfoxide. They were diluted to final concentrations with E3+ medium (5 mM NaCl, 0.17 mM KCl, 0.33 mM CaCl₂, 0.33 mM MgSO₄ and 0.1 µg/mL methylene blue).

We examined the inhibitory activities of food constituents in cell proliferation assays. Test compounds used in the assays were as follows: curcumin (Wako or Sigma-Aldrich), zerumbone (Wako), genistein (Sigma-Aldrich), chalcone (Wako), corosolic acid (Wako), carnosol (Wako), ursolic acid (Wako), epigallocatechin (Sigma-Aldrich), isoflavone (Wako), apigenin (Wako), chrysin (Wako), flavanone (Wako), resveratrol (Wako), flavone (Wako), quercetin (Wako), daidzein (Wako), and clodronate (Sigma-Aldrich). These compounds were firstly dissolved with dimethyl sulfoxide (DMSO; Wako) and then appropriately diluted with RPMI1640 + 10% FCS to apply the assays. The final concentration of DMSO was adjusted not to exceed 1% at most in cell cultures.