1. Natural Products Group, Nobel Project Laboratory, National Research Centre, El-Behoos St., Dokki, Cairo, Egypt
2. Department of Pharmacognosy, Faculty of Pharmacy, Helwan University, Helwan, Egypt
3. Department of Medicinal Chemistry, Theodor Bilharz Research Institute, Giza, Egypt
4. Cancer Biology Laboratory, Nobel Biotechnology Centre, Department of Biochemistry, National Research Centre, Dokki, Cairo, Egypt
5. Department of Pharmacognosy, Faculty of Pharmacy, Cairo University, Kasr-el-Aini St., 11562 Cairo, Egypt. Fax: +2027426807.