Microbial transformation of mycophenolic acid: Part II

Bioconversion of mycophenolic acid (MPA, I) having considerable immuno-suppressant activity was attempted with a great number of microorganisms. Four Streptomyces strains were selected, which transformed MPA to various bioconversion products. These derivatives of MPA (II–VI) were isolated and their structures were determined by IR, 1H, 13C NMR and mass spectroscopic methods. In the course of bioconversions, mycophenolic acid underwent one or more of the following transformations: hydroxylation on the side chain or on the lactone ring, amide and alcohol formation from the carboxylic acid group, oxidative cyclizations of the side chain and glycosylation.