Microbial transformation of amino- and hydroxyanthraquinones by Beauveria bassiana ATCC 7159.

Microbial biotransformation of four amino- and hydroxyanthraquinones catalyzed by Beauveria bassiana ATCC 7159 has been studied. Incubation of 1,2-diaminoanthraquinone (1) with B. bassiana ATCC 7159 afforded 1-amino-2-(4'-O-methyl-2beta-N-D-glucopyranosylamino)anthraquinone (5) in a hitherto unprecedented biotransformation involving N-glycosylation of an amine. Biotransformation of 1-aminoanthraquinone (2) yielded 1-amino-2-(4'-O-methyl-2beta-O-D-glucopyranosyloxy)anthraquinone (6) as a result of microbial hydroxylation of C-2 followed by 4'-O-methyl-glucosylation of the newly introduced hydroxyl group. 1,8-Dihydroxyanthraquinone (3) and 1,2-dihydroxyanthraquinone (4) afforded 8-hydroxy-1-(4'-O-methyl-1beta-O-D-glucopyranosyloxy)anthraquinone (7) and 1-hydroxy-2-(4'-O-methyl-2beta-O-D-glucopyranosyloxy)anthraquinone (8), respectively, resulting from 4'-O-methyl-glucosylation of the existing hydroxyl groups of the substrates. The efficiency of these conversions suggests that microbial biotransformation reactions offer an attractive alternative to chemical 4'-O-methyl-glucosylation of amino- and hydroxyanthraquinones.