1. Center for Biomaterials and Biopathways and Department of Chemistry Zhejiang University Hangzhou, Zhejiang 310027 (P. R. China)
2. State Key Laboratory of Pathogen and Biosecurity Beijing Institute of Microbiology and Epidemiology Beijing 100071 (P. R. China)
3. Department of Traditional Chinese Medicine and Natural Drug Research Zhejiang University Hangzhou 310058 (P. R. China)