Abstract
Microbial transformation studies of the eudesmanolide vulgarin (
1
) have revealed that it was metabolized by a number of microorganisms. Using a standard two-stage fermentation technique,
Beauvaria bassiana
(ATCC 7159) produced one more polar metabolite
2
. Moreover,
Hansenula anomala
(ATCC 20170) partially converted vulgarin into another less polar metabolite
3
and a more polar one
4
. These metabolites were characterized on the basis of their spectral data as 1-
epi
-tetrahydrovulgarin (1
α
,4
α
-dihydroxy-5
α
H,6,11
β
H-eudesman-6,12-olide,
2
), dihydrovulgarin (4
α
-hydroxy-1-oxo-5
α
H,6,11
β
H-eudesman-6,12-olide,
3
), and 3
α
-hydroxydihydrovulgarin (3
α
,4
α
-dihydroxy-1-oxo-5
α
H,6,11
β
H-eudesman-6,12-olide,
4
). Metabolite
4
identity was further confirmed through chemical synthesis.