Microbial transformation of cefotaxime and medrysone and the biological activity of their metabolites

Abstract

Microbial transformation has been widely used in the past decades for the production of analogues of several bioactive compounds that are hardly synthesized by classical chemical routes. Cefotaxime, a drug to which many bacteria are gaining resistance, was fed to several fungi in the hope of obtaining a biotransformed product having a functional group that would bypass this resistance. Cefotaxime was not biotransformed by Cunninghamella blackesleenea, Rhizopus stolonifer, Aspergillus niger and Cunninghamella blackesleenea. Medrysone is a steroidal drug used to treat conjunctive inflammations. Microbial biotransformation of medrysone was investigated using Rhizopus stolonifer. Four metabolites were obtained; three were previously identified and the fourth is a newly synthesized compound. This new metabolite was not found to be cytotoxic thus the biological activity should be studied. This work led to the optimization of methods to biotransform antibiotics such as cefotaxime (choice of TLC plates and extraction) and to the discovery of new metabolites that can be potential drug candidates.