Fungal transformation of isosteviol lactone and its biological evaluation for inhibiting the AP-1 transcription factor

Bo Hon Chou, Li Ming Yang, Shwu Fen Chang, Feng Lin Hsu, Chia Hsin Lo, Wen Kuang Lin, Li Hsuan Wang, Pan Chun Liu, Shwu Jiuan Lin

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17 Citations (Scopus)


A number of hydroxylated diterpenoids were obtained from the microbial transformation of isosteviol lactone (4α-carboxy-13α-hydroxy-13,16-seco-ent-19-norbeyeran-16-oic acid 13,16-lactone) (2) with Mucor recurvatus MR 36, Aspergillus niger BCRC 31130, and Absidia pseudocylindrospora ATCC 24169. Incubation of 2 with M. recurvatus and Asp. niger led to isolation of seven known compounds (1 and 3-8). Incubation of 2 with Abs. pseudocylindrospora produced 5 and six previously unreported compounds (9-14). The structures of these isolated compounds were deduced by high-field NMR techniques (1H, 13C, DEPT, COSY, NOESY, HSQC, and HMBC), and those of 9 and 11 were further confirmed by X-ray crystallographic analyses. Subsequently, the inhibitory effects on activator protein-1 (AP-1) activation in lipopolysaccharide-stimulated RAW 264.7 macrophages of all of these compounds were evaluated. Compounds 2-5, 8, 9, 11, and 12 exhibited significant inhibitory activity, while 3 was more potent than the reference compound of dexamethasone.

Original languageEnglish
Pages (from-to)759-764
Number of pages6
Issue number6
Publication statusPublished - Apr 2009



  • Activator protein-1
  • Diterpenoid
  • Isosteviol lactone
  • Microbial transformation

ASJC Scopus subject areas

  • Plant Science
  • Biochemistry
  • Molecular Biology
  • Horticulture

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