1. Natural Product Research Center; KIST Gangneung Institute; Gangneung 210-340 Republic of Korea
2. Department of Chemistry; Gangneung-Wonju National University; Gangneung 210-340 Republic of Korea
3. Department of Chemistry & MedChem Program of Life Science Institute; National University of Singapore; Singapore 117543 Singapore
4. Department of Biological Chemistry; University of Science and Technology; Daejon 305-350 Republic of Korea