Molecules (Jan 2019)

Biotransformed Metabolites of the Hop Prenylflavanone Isoxanthohumol

  • Hyun Jung Kim,
  • Soon-Ho Yim,
  • Fubo Han,
  • Bok Yun Kang,
  • Hyun Jin Choi,
  • Da-Woon Jung,
  • Darren R. Williams,
  • Kirk R. Gustafson,
  • Edward J. Kennelly,
  • Ik-Soo Lee

DOI
https://doi.org/10.3390/molecules24030394
Journal volume & issue
Vol. 24, no. 3
p. 394

Abstract

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A metabolic conversion study on microbes is known as one of the most useful tools to predict the xenobiotic metabolism of organic compounds in mammalian systems. The microbial biotransformation of isoxanthohumol (1), a major hop prenylflavanone in beer, has resulted in the production of three diastereomeric pairs of oxygenated metabolites (2⁻7). The microbial metabolites of 1 were formed by epoxidation or hydroxylation of the prenyl group, and HPLC, NMR, and CD analyses revealed that all of the products were diastereomeric pairs composed of (2S)- and (2R)- isomers. The structures of these metabolic compounds were elucidated to be (2S,2„S)- and (2R,2„S)-4′-hydroxy-5-methoxy-7,8-(2,2-dimethyl-3-hydroxy-2,3-dihydro-4H-pyrano)-flavanones (2 and 3), (2S)- and (2R)-7,4′-dihydroxy-5-methoxy-8-(2,3-dihydroxy-3-methylbutyl)-flavanones (4 and 5) which were new oxygenated derivatives, along with (2R)- and (2S)-4′-hydroxy-5-methoxy-2„-(1-hydroxy-1-methylethyl)dihydrofuro[2,3-h]flavanones (6 and 7) on the basis of spectroscopic data. These results could contribute to understanding the metabolic fates of the major beer prenylflavanone isoxanthohumol that occur in mammalian system.

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