1. Bioactive Marine Natural Products Chemistry Research Unit (BMNCU), Department of Pharmacognosy, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Pathumwan, Bangkok 10330, Thailand, Department of Physics, Faculty of Science and Technology, Thammasart University, Rangsit, Pathumthani 12121, Thailand, and Laboratory of Organic Chemistry, Graduate School of Bioagricultural Science, Nagoya University, Chikusa, Nagoya 464-8601, Japan