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. Faculty of Sciences and Liberal Arts, Rajamangala University of Technology Isan, Nakhon Ratchasima, Thailand
3. Department of Microbiology, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand
4. Departments of Chemistry and Earth, Ocean & Atmospheric Sciences, University of British Columbia, Vancouver, BC, Canada
5. Natural Products Research Section, Research Division, National Cancer Institute, Bangkok, Thailand