Microbial transformation of isosteviol lactone and evaluation of the transformation products on androgen response element

Bo Hon Chou, Li Ming Yang, Shwu Fen Chang, Feng-Lin Hsu, Chia Hsin Lo, Jia Horng Liaw, Pan Chun Liu, Shwu Jiuan Lin

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13 Citations (Scopus)


Two filamentous fungi, Cunninghamella bainieri ATCC 9244 and Aspergillus niger BCRC 32720, were used to investigate the biotransformation of isosteviol lactone (4α-carboxy-13α-hydroxy-13,16-seco-ent-19-norbeyeran-16-oic acid 13,16-lactone) (2), which was derived by reacting isosteviol (ent-16-oxobeyeran-19-oic acid) (1) with m-chloroperbenzoic acid. Incubation of 2 with C. bainieri afforded metabolites 3-6, which involved isomerization, hydroxylation, and ring cleavage reactions followed by oxidation and selective O-methylation. Incubation of 2 with A. niger afforded mono-, di-, and trihydroxylated metabolites 3, 4, and 7-12. The structures of 3-12 were elucidated on the basis of spectroscopic analyses, and structures 3, 4, and 6 were confirmed by X-ray crystallographic studies. Compounds 2-6, 8-10, and 12 were assayed as androgen agonists using an ARE (androgen response element)-mediated luciferase reporter gene assay. Compounds 3, 6, and 10 were significantly active, with 6 showing more activity than testosterone.

Original languageEnglish
Pages (from-to)602-607
Number of pages6
JournalJournal of Natural Products
Issue number4
Publication statusPublished - Apr 2008


ASJC Scopus subject areas

  • Plant Science
  • Chemistry (miscellaneous)
  • Drug Discovery
  • Organic Chemistry
  • Pharmacology

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