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. Department of Pharmacology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
3. Integrated Nanotechnology Research Centre, Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand