Metabolism of Steviol and Its Derivatives by Gibberella Fujikuroi

Abstract

Steviol (ent-13-hydroxykaur-16-en-19-oic acid)* is metabolized by Gibberella fujikuroi in the presence of inhibitors of gibberellin biosynthesis, such as quaternary ammonium salt-type growth retardants, to afford 7β-hydroxy- and 6β, 7β-dihydroxysteviol, gibberellins A1, A18, A19, A53 and 7β 13-dihydroxykaurenohde. Steviol acetate (ent-13-acetoxykaur-16-en-19-oic acid) is also metabo-lized to the 6β and to the 13-acetyl derivatives of gibberellins A17 and A20 and steviol methyl ester (methyl ent-13-hydroxykaur-16-en-19-oate) into the monohydroxy-, dihydroxy- and hydroxyoxo-derivatives. These results indicate a low substrate specificity of the enzymes in the fungus and provide a useful preparative methodology of several important plant gibberellins carrying the 13-hydroxyl group. © 1982, Japan Society for Bioscience, Biotechnology, and Agrochemistry. All rights reserved.