1. School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, P.R. China
2. Program in Public Health, College of Healthy Sciences, University of California—Irvine, Irvine, California 92697,United States
3. Institute of Chinese Medical Sciences, Guangdong Pharmaceutical University, Guangzhou 510006, P.R. China
4. Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008, United States