1. Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province, Shantou University, Shantou, Guangdong Province 515063, P. R. China
2. Department of Biology, Shantou University, Shantou, Guangdong Province 515063, P. R. China
3. Department of Medicinal Chemistry, Shantou University Medical College, Shantou, Guangdong Province 515041, P. R. China
4. The Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong Province 515041, P. R. China