1. Chronic Diseases Research Center, Dalian University College of Medicine, Dalian, Liaoning 116622, P. R. China
2. Department of Oral Teaching and Research, Yanbian University College of Medicine, Yanji, Jilin Province 133002, P. R. China
3. Key Laboratory of Natural Medicines of the Changbai Mountain, Ministry of Education, College of Pharmacy, Yanbian University, Yanji, Jilin Province 133002, P. R. China