1. Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Khartoum, Khartoum, P.O. Box 1996, Sudan
2. Department of Pharmacognosy, Faculty of Pharmacy, University of Khartoum, Khartoum, P.O. Box 1996, Sudan
3. Faculty of Medical Laboratory Sciences, University of Khartoum, Khartoum, Sudan
4. Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia