Chemical studies on functionality and toxicity of food polysulfides derived from cooking

• Project/Area Number: 17500532
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Eating habits, studies on eating habits
• Research Institution: Ochanomizu University
• Principal Investigator: MORIMITSU Yasujiro Ochanomizu University, Graduate School of Humanities and Sciences., Associate Prof, 人間文化研究科, 助教授 (00244533)
• Project Period (FY): 2005 – 2006
• Project Status: Completed (Fiscal Year 2006)
• Budget Amount: ¥3,500,000 (Direct Cost: ¥3,500,000); Fiscal Year 2006: ¥800,000 (Direct Cost: ¥800,000); Fiscal Year 2005: ¥2,700,000 (Direct Cost: ¥2,700,000)
• Keywords: polysulfide / detoxification enzymes / garlic / diallyl trisulfide / diallyl disulfide / allicin / oxidative stress / reactive oxygen species / 第一相解毒酵素 / 第二相解毒酵素誘導 / 第二相解毒酵素

Research Abstract

Diallyl trisulfide (DAIS) and diallyl disulfide (DADS), oil-soluble components of garlic, were shown to induce phase II enzymes in vitro and in vivo. The detailed mechanism of induction activity of these compounds has not been elucidated completely, although several hypotheses have been proposed. To establish the role of redox stress involved in induction of phase II enzymes by the Album polysulfides, we compared the ability of mono-, di- and trisulfides to generate ROS, the ESR spectrometry and the GST (glutathione S transferase) induction activity in rat liver epithelial RL34 cells. The proposed mechanisms of redox stress between the Album polysulfides and glutathione (GSH) were also discussed.
The polysulfides were tested for the inducing ability of ROS levels by means of DCF fluorescence in RL34 cells. Trisulfides were successfully demonstrated to generate free radicals in RL34 cells in order of DATS (diallyltrisulfide) > DADS (diallyldisulfide) > DAS (diallylsulfide). In the ESR experiment, the hydroxyl radicals were gradually detected from half hour after the reaction initiated by adding trisulfides with GSH. These data suggested that the redox cycling between trisulfides and GSH was likely to go along according to the polysulfide-thiol pathway, which products were reported to be superoxide and unstable perthiol (RSSH).
On the other hand, the induction activity of QR (quinone reductase) was also measured in RL34 cells. Not only trisulfides but also disulfides potently induced QR, especially DADS. DADS with thiols could not be detected any signals in the ESR experiment. We considered that DADS might preferentially be metabolized to a certain strong electrophile. We supposed that allicin (diallylthiosulfinate), a strong electrophile, was generated from DADS by metabolism of CYP2E1 as one possible candidate. However, the inductions of any CYPs were not detected in addition of DADS in RL34 cells.

Research Products

• [Journal Article] Sulfides (2007)
  • Author(s): Y.Morimitsu
  • Journal Title: Safety guide book for functional foods (edited by T.Tsusida et al.)(Science Forum) Chapter 11 Pages: 396-400
  • Description: 「研究成果報告書概要(欧文)」より
• [Book] 「機能性食品の安全性ガイドブック」 11.スルフィド (2007)
  • Author(s): 森光 康次郎 (分担)
  • Publisher: サイエンスフォーラム
  • Description: 「研究成果報告書概要(和文)」より