Biotransformation of swertiamarin by Aspergillus niger.

The biotransforamtion of swertiamarin has been carried out using Aspergillus niger. The results showed that 60% swertiamarin were metabolized into two metabolites during the 5 days of biotransformation. The metabolites were identified as erythrocentaurin and 5-ethylidene-8-hydroxy-3,4,5,6,7,8-hexahydro-1Hpyrano[3,4-c]-pyridine-1-one, a novel alkaloid, with NMR and MS. The hydrolysis of glucosidic bond catalyzed by β-D-glucosidase was found to be the rate-limiting reaction in pathway of biotransformation of swertiamarin.