Biotransformation of Flavonoids with -NO 2 , -CH 3 Groups and -Br, -Cl Atoms by Entomopathogenic Filamentous Fungi.

Combining chemical and microbiological methods using entomopathogenic filamentous fungi makes obtaining flavonoid glycosides possible. In the presented study, biotransformations were carried out in cultures of KCH J1.5, KCH J2, and KCH J2.6 strains on six flavonoid compounds obtained in chemical synthesis. As a result of the biotransformation of 6-methyl-8-nitroflavanone using the strain KCH J2, two products were obtained: 6-methyl-8-nitro-2-phenylchromane 4--D-(4″--methyl)-glucopyranoside and 8-nitroflavan-4-ol 6-methylene--D-(4″--methyl)-glucopyranoside. 8-Bromo-6-chloroflavanone was transformed by this strain to 8-bromo-6-chloroflavan-4-ol 4'--D-(4″--methyl)-glucopyranoside. As a result of microbial transformation by KCH J2.6 effectively biotransformed only 8-bromo-6-chloroflavone into 8-bromo-6-chloroflavone 4'--D-(4″--methyl)-glucopyranoside. KCH J1.5 was able to transform 6-methyl-8-nitroflavone to 6-methyl-8-nitroflavone 4'--D-(4″--methyl)-glucopyranoside, and 3'-bromo-5'-chloro-2'-hydroxychalcone to 8-bromo-6-chloroflavanone 3'--D-(4″--methyl)-glucopyranoside. None of the filamentous fungi used transformed 2'-hydroxy-5'-methyl-3'-nitrochalcone effectively. Obtained flavonoid derivatives could be used to fight against antibiotic-resistant bacteria. To the best of our knowledge, all the substrates and products presented in this work are new compounds and are described for the first time.