1. Department of Biology, College of Science, Shantou University, Shantou 515063, Guangdong, P.R. China
2. Key Laboratory of Carbohydrate Chemistry and Biotechnology, School of Biotechnology, Jiangnan University, Wuxi 214122, Jiangsu, P.R. China
3. State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, Jiangsu, P.R. China
4. Southwest Center for Natural Products Research, The University of Arizona, 250 East Valencia Road, Tucson, Arizona 85706, United States