Sulfanilamide Derivatives Effectiveness on Growth Inhibition in E. coli and S. aureus Tiffani Ream, Department of Biological Sciences, York College of PA Acetanilide Methods Ammonia N-butylamine Sec-butylamine Piperidine Morpholine Derivatives Antibiotic Disks ( µM) E. coliS. aureus Measure zone of inhibition Determine EC 50 CompoundE. coliS. aureus Sulfanilamide10.78 a No fit Ammonia N-butylamine Sec-butylamine x10 6 Morpholine Piperidine5.91x x10 8 Results Sulfa drugs have been used in medicine since 1932 when Farbenindustrie patented Protonsil (Williamson, Mindard, & Masters 2007). The original sulfanilamide was synthesized in 1908, along with thousands of derivatives. In 1940, Domagk won the Nobel Prize for his research in sulfanilamide derivative development. However, due to the technology of the time, most of the papers and research he and other performed is not accessible or readily available. Sulfa drugs are competitive inhibitors of p-aminobenzoic acid (PABA) (Woods 1941). Bacteria require PABA in the synthesis of folic acid, which is crucial for cell replication. Normally, PABA binds to dihydropteroate synthetase; however, when sulfanilamide is present, competition occurs between PABA and the drug (Yoneeyma & Katsumata 2006). The resulting compound of sulfanilamide/dihydropteroate synthetase complex is not functional in the folic acid synthesis pathway, thus causing cell cycle arrest. A standard practice in pharmaceutics is to take an effective drug and modify it to uncover a more efficient product or one with more suitable qualities such as solubility or polarity. To do this, chain lengths are modified and functional groups are added. The objective of this study is to examine derivatives of sulfanilamide for a more effective compound. Both chain lengths and functional groups were varied in this study in the attempt to find a more effective derivative of sulfanilamide. Introduction Questions Asked 1.Is the standard sulfanilamide the most effective sulfa drug? 2.Are trends evident within the different sulfanilamide derivatives? 3.Do differences between gram positive and gram negative bacteria exist? Figure 1. Comparison of area of inhibition between E. coli (left) and S. aureus(right) in ammonia, n-butylamine, sec-butylamine derivatives of sulfanilamide and the standard. Means (n=6) and standard of error were calculated for each concentration. An EC 50 for each derivative and the standard sulfanilamide was determined from these graphs. Space filling model of sulfanilamide. Figure 2. Comparison of area of inhibition between E. coli (left) and S. aureus(right) in morpholine and piperidine derivatives of sulfanilamide and the standard. Means (n=6) and standard of error were calculated for each concentration. An EC 50 for each derivative and the standard sulfanilamide was determined from these graphs. Area of Inhibition Measured Results Literature Cited Williamson, K.L., R.D. Minard, and K.M. Masters Macroscale and Microscale Organic Experiments. Houghton Mifflin: Boston, MA. Woods, W.B Studies on the Antibacterial Action of Sulfonamide Drugs. JEM Yoneyama, H. and R. Katsumata Antibiotic Resistance in Bacteria and Its Future for Novel Antibiotic Development. Bioscience, Biotechnology, Biochemistry. 70.5, Sulfanilamide is the most effective compound in E. coli (EC 50 =10.78 µM), while the morpholine derivative is most effective in S. aureus (EC 50 =40.82 µM). Morpholine is 3x10 5 times more effective than Piperidine in both gram positive and gram negative. Sec-butylamine (EC 50 =178.70) was more effective than N-butylamine (EC 50 =257.50) in E. coli only. N-butylamine (EC 50 =47.36) was 1x10 5 times more effective in S. aureus. Table 1. EC 50 Table of Sulfanilamide and Sulfanilamide derivatives. a = µM Acknowledgments I would like to thank Dr. Kaltreider and Dr. Halligan for all of their help and guidance in this project. I would also like to thank Brian Kanaskie and Bethany Remeniuk for their help in the lab. Conclusion Sulfanilamide is the most effective compound in E. coli, while Morpholine is more effective in S. aureus. Polar substitutents are more effective than non-polar functional groups. Branched carbon chains are more effective in E. coli, while a straight chain has a lower EC 50 in S. aureus. More of a contrast in effectiveness of chain length is evident in S. aureus. The parent compound, sulfanilamide, is the most effective in E. coli, while the morpholine derivative is most effective in S. aureus. Due to the disparity between gram positive and gram negative, further research is necessary to determine the cause. Structural differences in the dihydropteroate synthetase or the structural differences of the cell wall may be the cause of these different results. Summary