Steviol derivatives have been submitted to biotransformations by fungi. Methyl ent-11beta,13-dihydroxy-15,16-epoxikauran-19-oate was hydroxylated at C-11 by Aspergillus niger, whereas ent-16beta-hydroxybeyeran-19-oic acid was hydroxylated at C-6 and C-7 by Fusarium moniliforme. The hydroxylation at non-activated positions at the carbon skeleton is discussed in connection with the properties of important polyhydroxylated diterpenoids described in the literature.
kaurene and beyerane diterpenes; steviol; biotransformation; Aspergillus niger; Fusarium moniliforme
