1. Department of Chemistry, University of Missouri, 125 Chemistry Building Columbia, Missouri 65211, United States
2. Pharmacognosy Department, Faculty of Pharmacy, Cairo University, Kasr El-Aini, Cairo, Egypt 11562
3. Pfizer, Inc., 700 Chesterfield Parkway, Chesterfield, Missouri 63017, United States
4. Department of Biochemistry, University of Missouri, 125 Chemistry Building Columbia, Missouri 65211, United States