ABSTRACT
Anaerobic incubation of prednisone 1 with human intestinal bacteria (HIB) afforded nine metabolites: 5beta-androst-1-ene-3,11,17-trione 3, 3alpha-hydroxy-5alpha-androstane-11,17-dione 4, 3beta,17alpha,20-trihydroxy-5alpha-pregnan-11-one 5, 3alpha,17alpha-dihydroxy-5alpha-pregnane-11,20-dione 6, 3alpha,17alpha-dihydroxy-5beta-pregnane-11,20-dione 7, 3beta,17beta-dihydroxy-5alpha-androstan-11-one 8beta, 3beta,17alpha-dihydroxy-5alpha-androstan-11-one 8alpha, 3alpha,17beta-dihydroxy-5alpha-androstan-11-one 9beta, and 3alpha,17alpha-dihydroxy-5alpha-androstan-11-one 9alpha. The structures of these metabolites (3-9) were elucidated using several spectroscopic techniques. Computer-aided prediction of potential biological activities of the isolated prednisone metabolites (3-9) revealed potential inhibition of prostaglandin E2 9-ketoreductase (PGE2 9-KR). Docking studies applied to PGE2 9-KR allowed recommendation of the metabolites 4, 8beta, and 8alpha for further pharmacological study as PGE2 9-KR inhibitors.