Hydrolysis of timosaponin BII by the crude enzyme from Aspergillus niger AS 3.0739

Abstract

Timosaponin BII (1), a steroidal saponin showing potential anti-dementia activity, was regioselectively hydrolyzed into its deglycosyl derivatives by the crude enzyme from Aspergillus niger AS 3.0739. Three biotransformation products, timosaponin BII-a (2), timosaponin BII-b (3), and timosaponin BII-c (4), were purified and their structures were elucidated on the basis of 1D NMR, 2D NMR, FAB-MS, and HR-ESI-MS spectral data. Compounds 2 and 3 are new compounds.

Keywords:

• biotransformation
• steroidal saponin
• timosaponin BII
• Aspergillus niger
• hydrolysis

Acknowledgements

This work was financially supported by the Major Program of Municipal Natural Science Foundation of Beijing (790001) and the National Natural Science Foundation of China (No. 30572333). The authors are grateful to Mrs Yan Xue and Mr He-Bing Chen of the National Center of Biomedical Analysis for the measurements of the MS and NMR spectra.