1. Biotechnology Research Institute, The Chinese Academy of Agricultural Sciences, 12 Zhongguancun South Street, Beijing 100081, P. R. China
2. Southwest Center for Natural Products Research, University of Arizona, 250 E. Valencia Rd., Tucson, AZ 85706, USA
3. VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT, Espoo, Finland