1. Chemistry of Natural and Microbial Products Department, Pharmaceutical and Drug Industries Research Division, National Research Centre, 33 El Bohouth St., Dokki, Giza 12622, Egypt
2. Department of Therapeutic Chemistry, National Research Centre, 33 El Bohouth St., Dokki, Giza 12622, Egypt
3. Pharmacology Department, National Research Centre, 33 El Bohouth St., Dokki, Giza 12622, Egypt
4. School of Pharmacy, University of Reading, Whiteknights, Reading, RG6 6AD, UK