The microbial transformation of anabolic androgenic steroid mestanolone (1) with Macrophomina phaseolina and Cunninghamella blakesleeana has afforded seven metabolites. The structures of these metabolites were characterized as 17b-hydroxy-17a-methyl-5a-androsta-1-ene-3,11-dione (2), 14a,17b-dihydroxy-17a-methyl-5a-androstan-3,11-dione (3), 17b-hydroxy-17a-methyl-5a-androstan-1,14-diene-3,11-dione (4), 17b-hydroxy-17a-methyl-5a-androstan-3,11-dione (5), 11b,17b-dihydroxy-17a-methyl-5a-androstan-1-ene-3-one (6), 9a,11b,17b-trihydroxy-17a-methyl-5a-androstan-3-one (7), and 1b,11a,17b-trihydroxy-17a-methyl-5a-androstan-3-one (8). All the metabolites, except 5 and 6, were identified as new compounds. Substrate 1 (IC 50 ¼ 27.6 AE 1.1 mM), and its metabolites 2 (IC 50 ¼ 19.2 AE 2.9 mM) and 6 (IC 50 ¼ 12.8 AE 0.6 mM) exhibited moderate cytotoxicity against the HeLa cancer cell line (human cervical carcinoma). All metabolites were noncytotoxic to 3T3 (mouse fibroblast) and H460 (human lung carcinoma) cell lines. The metabolites were also evaluated for immunomodulatory activity, and all were found to be inactive. IntroductionBiotransformation has been widely used in organic chemistry for stereoslective synthesis.1-6 Biotransformation reactions can be achieved by a variety of agents, such as enzymes, animals and plant cell cultures, and microorganisms; however, microorganisms are most effectively used for this purpose. Microbial enzyme systems can be used for reduction, oxidation, hydroxylation, and Michael addition. Regio-and stereo-selective oxidation and hydroxylation of steroids have been extensively achieved through microbial transformation. The cytochrome P450 monooxygenase system, present in microorganismsparticularly in fungi -is responsible for the stereoselective hydroxylation at various sites of the steroidal skeleton. 7-9Mestanolone (1) (C 20 H 18 O 2 ) is a member of the anabolicandrogenic class of steroids. It is weakly anabolic and strongly androgenic. Mestanolone was rst synthesized by the oxidation of 17b-methylandrostan-3b,17b-diol. It is used as a starting material for the synthesis of other anabolic steroids, such as 17-methyl-1-testosterone, and oxandrolone.10,11 Compound 1 was earlier subjected to microbial transformation, and several new analogues were obtained. 12In continuation of our research on biotransformation of bioactive compounds, and drug molecules, 13-15 mestanolone (1) was incubated with Macrophomina phaseolina, and Cunninghamella blakesleeana, which yielded metabolites 2-8 ( Fig. 1 and 2). ExperimentalGeneral Mestanolone (1) was acquired from Hangzhu Dayangchem (Cat no. 541-11-9, China). Sabouraud dextrose agar (SDA) was purchased from Merck KGaA (Cat no. 146392, Germany). Silica gel precoated TLC plates (PF 254 , Merck KGaA, Germany) were used for thin layer chromatography; phosphomolybdic acid solution was used as a staining reagent for UV inactive compounds. Silica gel (70-230 mesh, Merck, Germany) was used for column chromatography. Final purication of the compounds was carried out...

Incubation of drostanolone heptanoate (1) with B. bassiana and M. phaseolina afforded seven new and two known metabolites.The main sites of hydroxylation include C-5, C-7, C-11, C-14, C-15, and C-20, hydrolysis at C-17, and reduction at C-3 of 1.