1. Laboratory of Natural Products, Inst. of Bioscience; Univ. Putra Malaysia; 43400 Serdang Malaysia
2. Dept. of Food Science, Faculty of Food Science and Technology; Univ. Putra Malaysia; 43400 Serdang Malaysia
3. Dept. of Chemistry, Faculty of Science; Univ. Putra Malaysia; 43400 UPM Serdang Selangor Malaysia