H. Ibrahim1, K. S. Sim1*, D. R. Syamsir1, N. R. Mohd. Nor2, A. M. Sri Nurestri1 and K. Awang2
1Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia.
2Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia.
