1. Graduate School of Pharmaceutical Sciences, Tokushima University, Tokushima 770-8505, Japan
2. Department of Botany, Faculty of Biological Sciences, Jahangirnagar University, Savar, Dhaka 1342, Bangladesh
3. Medical Center, Duke University, Durham, North Carolina 27710, United States
4. Natural Products Laboratory, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599, United States