1. Department of Applied Chemistry and State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei 230036, P. R. China
2. Department of Chemistry, College of Sciences, King Saud University, Riyadh 11451, Saudi Arabia
3. Department of Science, Faculty of Science, Yamagata University, 1-4-12 Kojirakawa, Yamagata 990-8560, Japan
4. Institute of Shandong Non-Metallic Materials, Jinan 250031, P. R. China