Structural analysis of novel bioactive acylated steryl glucosides in pre-germinated brown rice bran

Seigo Usuki, Toshio Ariga, Somsankar Dasgupta, Takeshi Kasama, Keiko Morikawa, Shota Nonaka, Yasuhide Okuhara, Mitsuo Kise, Robert K. Yu

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

Previous studies from our laboratory indicated that pre-germinated brown rice (PR) contained certain unknown bioactive lipids that activated two enzymes related to diabetes: Na+/K+ ATPase and homocysteine-thiolactonase. In this paper, we report on the isolation and structural characterization of the activator lipids from PR bran as acylated steryl glucosides (ASGs). The activator lipid was isolated by silica gel column chromatography, and its chemical structure was determined by NMR, GC-MS, and tandem mass spectrometry. We demonstrated that the bioactive component consists of a mixture of acylated steryl β-glucosides. Δ8-cholesterol and 2-hydroxyl stearic acid were identified as constituents of ASGs. The steryl glucosides (SGs) subsequent to alkaline hydrolysis lost this enzyme activator activity. Soybean-derived ASGs were not active. This activity may be quite peculiar to PR-derived ASGs. Our findings suggest that the molecular species of ASG may play an important contributing role in the anti-diabetic properties of a PR diet.

Original languageEnglish (US)
Pages (from-to)2188-2196
Number of pages9
JournalJournal of Lipid Research
Volume49
Issue number10
DOIs
StatePublished - Dec 1 2008

Keywords

  • ATPase
  • Diabetes
  • Homocysteine glycolipids
  • Steryl glucoside

ASJC Scopus subject areas

  • Biochemistry
  • Endocrinology
  • Cell Biology

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    Usuki, S., Ariga, T., Dasgupta, S., Kasama, T., Morikawa, K., Nonaka, S., Okuhara, Y., Kise, M., & Yu, R. K. (2008). Structural analysis of novel bioactive acylated steryl glucosides in pre-germinated brown rice bran. Journal of Lipid Research, 49(10), 2188-2196. https://doi.org/10.1194/jlr.M800257-JLR200