1. Cancer Center, The Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong 524001, P.R. China
2. Guangdong Key Laboratory for Research and Development of Natural Drugs, Guangdong Medical University, Zhanjiang, Guangdong 524023, P.R. China
3. Institute of Traditional Chinese Medicine and Natural Products, Jinan University, Guangzhou, Guangdong 510632, P.R. China