Microbial transformation of hydroxy metabolites of 1-oxohexyl derivatives of theobromine by Cunninghamella echinulata NRRL 1384

The biotransformation of pentoxifylline (PTX), propentofylline (PPT) and their racemic hydroxy metabolites ((±)-OHPTX and (±)-OHPPT) by using the fungus Cunninghamella echinulata NRRL 1384. A fungus Cunninghamella echinulata NRRL 1384 was used to catalyse the (S)-selective oxidation of the racemic hydroxy metabolites: (±)-OHPTX and (±)-OHPPT and for reduction of PTX and PPT. The first oxidation step appears to be selective and relatively fast while the second reduction step is slower and more selective with PTX. Modifications involving supplementing the bioconversion with glucose give yields and enantiomeric excess (ee) values similar to those obtained without glucose. The bioconversion of (±)-OHPTX gave an (R)-enantiomer (LSF-lisofylline) with a higher enantiopurity (maximum approximately 93% ee) compared to the bioconversion of (±)-OHPPT, when the maximum ee value for (R)-OHPPT was recorded at 83%. The conversion of (±)-OHPTX and (±)-OHPPT using Cunninghamella echinulata can be recognized as a process, which may be recommended as an alternative to the methods used to obtain (R)-OHPTX and (R)-OHPPT.