1. Department of Chemistry, Faculty of Science and Mathematics, Universiti Pendidikan Sultan Idris (UPSI), Tanjong Malim, Perak, Malaysia
2. School of Environmental and Natural Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
3. Department of Chemistry, University of Alabama in Huntsville, Huntsville, AL, USA
4. Aromatic Plant Research Center, Lehi, UT, USA
5. Innovation Centre in Agritechnology (ICA), Universiti Teknologi Malaysia, Pagoh, Johor, Malaysia