The microbiological transformation of 7alpha-hydroxy-ent-kaur-16-ene derivatives by Gibberella fujikuroi.
The biotransformation of 7alpha-hydroxy-ent-kaur-16-ene (epi-candol A) by the fungus Gibberella fujikuroi gave 7alpha,16alpha,17-trihydroxy-ent-kaur-16-ene and a seco-ring B derivative, fujenoic acid, whilst the incubation of candicandiol (7alpha,18-dihydroxy-ent-kaur-16-ene) and canditriol (7alpha,15alpha,18-trihydroxy-ent-kaur-16-ene) afforded 7alpha,18,19-trihydroxy-ent-kaur-16-ene and 7alpha,11beta,15alpha,18-tetrahydroxy-ent-kaur-16-ene, respectively. The presence of a 7alpha-hydroxyl group in epi-candol A avoids its biotransformation along the biosynthetic pathway of gibberellins, and directs it to the seco-ring B acids route. The 15alpha-hydroxyl group in canditriol inhibits oxidation at C-19 and direct hydroxylation at C-11(beta). The formation of fujenoic acid, from 7alpha-hydroxy-ent-kaur-16-ene, probably occurs via 7alpha-hydroxykaurenoic acid and 7-oxokaurenoic acid, with subsequent hydroxylation at the C-6(beta) position.
Fraga
Braulio M
BM
Instituto de Productos Naturales y Agrobiología, Avda. Astrofísico F. Sánchez 3, 38206-La Laguna, Tenerife, Canary Islands, Spain. bmfraga@ipna.csic.es <bmfraga@ipna.csic.es>
Bressa
Carlo
C
González
Pedro
P
Guillermo
Ricardo
R
Hernández
Melchor G
MG
Suárez
Sergio
S
D001711:Biotransformation; D004224:Diterpenes / Q000737:chemistry / Q000378:metabolism*; D005874:Gibberella / Q000201:enzymology / Q000378:metabolism*; D013379:Substrate Specificity
C522585:7alpha,15alpha,18-trihydroxy-ent-kaur-16-ene; C522584:7alpha-hydroxy-ent-kaur-16-ene; D004224:Diterpenes; C476659:candicandiol