1. Chemistry Department, Faculty of Science, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia
2. Chemistry Department, Faculty of Applied Science, Universiti Teknologi MARA, Jengka 26400, Pahang, Malaysia
3. Department of Pharmacy, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
4. Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia