1 Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran Jatinangor West Java Indonesia r.maharani@unpad.ac.id.
2 Central Laboratory, Universitas Padjadjaran Jalan Raya Bandung-Sumedang KM 21, Jatinangor 45363 West Java Indonesia.
3 Centre of Natural Products and Synthesis Studies, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran Jalan Raya Bandung-Sumedang KM 21, Jatinangor 45363 West Java Indonesia.
4 Department of Chemistry, Graduate School of Science, Osaka University Toyonaka Osaka 560-0043 Japan.
5 Department of Pharmaceutical Chemistry, School of Pharmacy, The University of Kansas 2095 Constant Avenue Lawrence Kansas 66047 USA siahaan@ku.edu.