1. Natural Products Research Unit, Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand
2. Integrated Nanotechnology Research Center, Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand
3. Department of Botany, Faculty of Science, Kasetsart University, Thailand
4. Clinical Research Section, Division of Research and Academic Support, National Cancer Institute, Bangkok, Thailand