A microbial model of mammalian metabolism: biotransformation of 4,5-dimethoxyl-canthin-6-one using Cunninghamella blakesleeana CGMCC 3.970

Abstract1. A filamentous fungus, Cunninghamella blakesleeana CGMCC 3.970, was applied as a microbial system to mimic mammalian metabolism of 4,5-dimethoxyl-canthin-6-one (1). Compound 1 belongs to canthin-6-one type alkaloids, which is a major bioactive constituent of a traditional Chinese medicine (the stems of Picrasma quassioides).2. After 72 h of incubation in potato dextrose broth, 1 was metabolized to seven metabolites as follows: 4-methoxyl-5-hydroxyl-canthin-6-one (M1), 4-hydroxyl-5-methoxyl-canthin-6-one (M2), canthin-6-one (M3), canthin-6-one N-oxide (M4), 10-hydroxyl-4,5-dimethoxyl-canthin-6-one (M5), 1-methoxycarbonl-β-carboline (M6), and 4-methoxyl-5-O-β-D-glucopyranosyl-canthin-6-one (M7).3. The structures of metabolites were determined using spectroscopic analyses, chemical methods, and comparison of NMR data with those of known compounds. Among them, M7 was a new compound.4. The metabolic pathways of 1 were proposed, and the metabolic processes involved phase I (O-demethylation, dehydroxyl...