1. Natural Products Research Unit, Department of Chemistry, Faculty of Science; Chulalongkorn University; 254 Phayathai Road Bangkok 10330 Thailand
2. Center for Petroleum, Petrochemicals and Advanced Materials; Chulalongkorn University; 254 Phayathai Road Bangkok 10330 Thailand
3. Program of Biotechnology, Faculty of Science; Chulalongkorn University; 254 Phayathai Road Bangkok 10330 Thailand
4. Department of Pharmaceutical Chemistry and Pharmacognosy, Faculty of Pharmaceutical Sciences; Naresuan University; Phitsanulok 65000 Thailand