Microbiological conversion of 12-oxygenated and other derivatives of ent-kaur-16-en-19-oic acid by Gibberella Fujikuroi, mutant B1-41a

The metabolism of several ring C and D-functionalized ent-kaur-16-en-19-oic acids by cultures of Gibberella fujikuroi, mutant B1-41a, to the corresponding derivatives of the normal fungal gibberellins (GAs) and ent-kaurenoids is described. A range of 12α- and 12β-hydroxyGAs and ent-kaurenoids are characterized by their mass spectra and GC Kovats retention indices. The mass spectral and GC data are used to identify the 12α-hydroxy derivatives of GA₁₂, GA₁₄, GA₃₇ and GA₄ (GA₅₈), and of the 12β-hydroxy derivatives of ent-7α-hydroxy- and ent-6α, 7α-dihydroxykaurenoic acids, in seeds of Cucurbita maxima. Similarly the metabolites of GA₉, formed in seeds of Pisum sativum and cultures of G.fujikuroi, mutant B1-41a, are identified as 12α-hydroxyGA₉. ent-11β-Hydroxy- and ent-11-oxo-kaurenoic acids are metabolized by the fungus to the corresponding 11-oxygenated derivatives of the normal fungal ent-kaurenoids and some C₂₀-GAs; no 11-oxygenated C₁₉-GAs are formed. Grandiflorenic acid, 11β-hydroxygrandiflorenic acid, attractyligen and ent-15β-hydroxykaurenoic acid are metabolized to unidentified products.