1. Department of Pharmacology; Faculty of Medicine; University of Malaya; 50603 Kuala Lumpur Malaysia
2. Department of Pharmacy; Faculty of Medicine; University of Malaya; 50603 Kuala Lumpur Malaysia
3. Cancer Research Initiatives Foundation (CARIF); Subang Jaya Medical Center; 47500 Subang Jaya Selangor Malaysia
4. Department of Chemistry; Texas A&M University; Box 30012, College Station Texas 77842 USA