1. Department of Chemistry, Faculty of Science and Mathematics, Sultan Idris Education University, 35900 Tanjung Malim, Perak Darul Ridzuan, Malaysia.
2. Department of Biology, Faculty of Science and Mathematics, Sultan Idris Education University, 35900 Tanjung Malim, Perak Darul Ridzuan, Malaysia.
3. Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia.
4. Atta-ur-Rahman Institute of Natural Product Discovery and Faculty of Pharmacy, University Technology MARA, Puncak Alam, 42300 Selangor, Malaysia.
5. Centre de Recherche de Gif, Institute de Chimie des Substances Naturelles, CNRS, 1, Avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France.