1. Hunan Key Laboratory of Traditional Chinese Veterinary Medicine, Hunan Agricultural University, Changsha, Hunan 410128, China
2. College of Veterinary Medicine, Hunan Agricultural University, Changsha, Hunan 410128, China
3. Institut für Organische Chemie, Universität Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany