Initial biotransformations of daunorubicin to aglycones by rat liver microsomes.

Anaerobic incubations of rat liver microsomes convert daunorubicin into at least six or seven aglycones in the presence of reduced nicotinamide adenine dinucleotide phosphate or a reduced nicotinamide adenine dinucleotide phosphate-generating system. The partial identification of some of the aglycones is based on cochromatographs of chemically synthesized derivatives by isocratic high-pressure liquid chromatography. The first major reaction is the reductive cleavage of daunorubicin to 7-deoxydaunorubicin aglycone which is converted to another product that cochromatographs with 7-deoxydaunorubicinol aglycone. The reaction follows first-order kinetics in a linear sequential pathway. Formation of 7-hydroxydaunorubicin aglycone is also identified as a product. Other reaction products are not yet identified.