Biotransformation of Neoruscogenin by the Endophytic Fungus Alternaria eureka


ÖZÇINAR Ö. , TAĞ O., YUSUFOĞLU H., KIVÇAK B. , Bedir E.

JOURNAL OF NATURAL PRODUCTS, cilt.81, ss.1357-1367, 2018 (SCI İndekslerine Giren Dergi) identifier identifier identifier

  • Cilt numarası: 81 Konu: 6
  • Basım Tarihi: 2018
  • Doi Numarası: 10.1021/acs.jnatprod.7b00898
  • Dergi Adı: JOURNAL OF NATURAL PRODUCTS
  • Sayfa Sayıları: ss.1357-1367

Özet

Biotransformation of neoruscogenin (NR, 1, spirosta-5,25(27)-diene-1 beta,3 beta-diol), the major bioactive sapogenin of Ruscus preparations, was carried out with the endophytic fungus Alternaria eureka. Fourteen new biotransformation products (2-15) were isolated, and their structures were elucidated by NMR and HRESIMS data analyses. A. eureka affected mainly oxygenation, oxidation, and epoxidation reactions on the B and C rings of the sapogenin to afford compounds 8-15. In addition to these, cleavage of the spiroketal system as in compounds 2-7 and subsequent transformations provided unusual metabolites. This is the first study reporting conversion of the spirostanol skeleton to cholestane-type metabolites 2-5. Additionally, the cleavage of the C-22/C-26 oxygen bridge yielding a furostanol-type steroidal framework and subsequent formation of the epoxy bridge between C-18 and C-22 in 7 was encountered for the first time in steroid chemistry.