1. School of Chemistry and Life SciencesHubei University of Education Wuhan 430205 P. R. China
2. Hubei Key Laboratory of Purification and Application of Plant Anti-Cancer Active Ingredients (Hubei University of Education) Wuhan 430205 P. R. China
3. Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University)Ministry of Educationand School of Pharmaceutical SciencesWuhan University Wuhan 430071 P. R. China