1. Faculties of Pharmacy, Science and Technology Research Institute (STRI), Chiang Mai, Thailand
2. Natural Products Research and Development Center (NPRDC), Science and Technology Research Institute (STRI), Chiang Mai, Thailand
3. Department of Microbial Genetics, Faculty of Biology, University of Tübingen, Tübingen, Germany
4. Boehringer Ingelheim Company, Ingelheim am Rhein, Germany
5. Medicine, Chiang Mai University, Science and Technology Research Institute (STRI), Chiang Mai, Thailand