Transformations of steroid esters by Fusarium culmorum

The course of transformations of the pharmacological steroids: testosterone propionate, 4-chlorotestosterone acetate, 17 beta-estradiol diacetate and their parent alcohols in Fusarium culmorum AM282 culture was compared. The results show that this microorganism is capable of regioselective hydrolysis of ester bonds. Only 4-ene-3-oxo steroid esters were hydrolyzed at C-17. 17 beta-Estradiol diacetate underwent regioselective hydrolysis at C-3 and as a result, estrone - the main metabolite of estradiol - was absent in the reaction mixture. The alcohols resulting from the hydrolysis underwent oxidation at C-17 and hydroxylation. The same products (6 beta- and 15 alpha-hydroxy derivatives) as from testosterone were formed by transformation of testosterone propionate, but the quantitative composition of the mixtures obtained after transformations of both substrates showed differences. The 15a-hydroxy derivatives were obtained from the ester in considerably higher yield than from the parent alcohol. The presence of the chlorine atom at C-4 markedly reduced 17 beta-saponification in 4-chlorotestosterone acetate. Only 3 beta,15 alpha-dihydroxy-4 alpha-chloro-5 alpha-androstan-17-one (the main product of transformation of 4-chlorotestosterone) was identified in the reaction mixture. 6 beta-Hydroxy-4-chloroandrostenedione, which was formed from 4-chlorotestosterone, was not detected in the extract obtained after conversion of its ester.