1. Department of Pharmaceutical Biosciences; Division of Toxicology; Uppsala University; Box 591 751 24 Uppsala Sweden
2. Department of Pharmacology, School of Pharmacy; Addis Ababa University; P O Box 1176 Addis Ababa Ethiopia
3. Department of Chemistry, Faculty of Science; El-Menoufia University; 32512 Shebin El-Kom Egypt
4. Department of Medicinal Chemistry, Division of Pharmacognosy; Uppsala University; Box 574 751 23 Uppsala Sweden
5. Department of Pharmaceutical Chemistry; School of Pharmacy; Addis Ababa University; P O Box 1176 Addis Ababa Ethiopia