Studies On The Biotransformation Of Intermediates Of Steroid Drugs By Mucor Silvaticus

In this thesis, the biotransformations of 3β-hydroxyl-5-ene and 4-ene-3-one steroids were studied by Mucor silvaticus which was screened from 20 fungal strains purchased. The strain Mucor silvaticus had the capability of biotransformation of steroids with high selectivity.The biotransformation of 3β-hydroxyl-5-ene steroids were carried out in Mucor silvaticus culture. It appears that the fungus predominantly hydroxylated at the 7αposition, the mixtures of 9α-, 11α-, 14α-hydroxyl, C7-oxo and C17-ketone reduced derivatives were also obtained. The relationships between the substrate structures and the hydroxylated positions had been discussed in detail. The hydroxylation positions and configuration of the metabolic products depended on the structure of the substrates. 7α-, 9α-Dihydroxylation and 7α-, 11α- dihydroxylation occurred in C21 steroids due to the effect of the acetyl side chain. The 7α- and 7β-hydroxyl epimers were obtained in the biotransformation of dehydroepiandrosterone, the low stereoselectivity was caused by C17-ketone group.A series of 4-ene-3-one steroids were incubated with Mucor silvaticus. It was found that the 4-ene-3-one steroids were hydroxylated mainly at 7αposition except 4-androstenedione, 6β-, 14α-hydroxylations and reductions of carbonyl at C-17 and C-20 also occurred during the transformations. The hydroxylated positions depended on the structure of the D-ring of steroids. 4-Androstenedione and progesterone were hydroxylated at the 14αposition, the 14αhydroxylase combined to the substrate easily for the free blockade of the 17-ketone group or acetyl side chain. It is quite possible that the 17α-hydroxyl group or 16, 17α-epoxy would prevent hydroxylation at the 14α-position.The biotransformation products were separated on silica gel column chromatography. The characterization of the metabolites was performed by various spectroscopic methods such as IR, ESI-MS, 1H NMR, 13C NMR and 2D-NMR. The complete assignments of 13C NMR chemical shifts of these compounds were obtained. The spectrum characterizations of compound 18 and 23 were analyzed in detail.