1. Department of Applied Chemistry and State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei 230036, P. R. China
2. Dongguan Key Laboratory of Drug Design and Formulation Technology, Key Laboratory of Research and Development of New Medical Materials of Guangdong Medical University, School of Pharmacy, Guangdong Medical University, Dongguan 523808, P. R. China
3. National Synchrotron Radiation Laboratory and Department of Chemical Physics, University of Science and Technology of China, Hefei 230029, P. R. China