1. Natural Products Research Unit, Center of Excellence for Innovation in Chemistry, Department of Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand
2. Department of Pharmacology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand
3. Integrated Nanotechnology Research Centre, Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand