Microbial transformation of dextromethorphan by Cunninghamella blakesleeana AS 3.153

The capability of Cunninghamella blakesleeana AS 3.153 to transform CYP2D6 probe drug dextromethorphan was investigated. Metabolites produced by strain AS 3.153 were detected by liquid chromatography-tandem mass spectrometry (LC-MS(n)) and the metabolite dextrorphan was identified by reference to confirm its structure. The yield of dextrorphan produced by C. blakesleeana AS 3.153 was over 90%. Quinidine, a CYP2D6 selective inhibitor, was applied to investigate its effect on biotransformation. The concentration of quinidine was 4-folds higher than that of dextromethorphan and the yield of dextrorphan was reduced by 84%, which proved there was drug metabolism enzyme similar to CYP2D6 in C. blakesleeana AS 3.153. It is concluded that C. blakesleeana AS 3.153 can be used as the suitable model strain in vitro to mimic human CYP2D6 metabolism.