[1] Univ Malaya, Fac Med, Dept Biomed Sci, Kuala Lumpur, Malaysia
[2] Univ Malaya, Fac Sci, Inst Biol Sci, Kuala Lumpur, Malaysia
[3] Karolinska Univ Hosp, Dept Expt Hematol, SE-14186 Stockholm, Sweden
[4] Univ Malaya, Dept Chem, Kuala Lumpur 59100, Malaysia
[5] Uppsala Univ, Dept Med Chem, Div Pharmacognosy, SE-75123 Uppsala, Sweden