1. Natural Products Research Unit, Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand
2. School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales, Australia
3. Department of Biochemistry, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand