Antibacterial and Antifungal Screening of Novel α-amino Acid Conjugated Bile Acid Derivatives

Three series of novel bile acid conjugates with different α–amino acid have been synthesized. The synthesis of final compounds was accomplished with anhydride using ethyl chloroformate. The conjugation was introduced via coupling of the bile acid anhydride with appropriately functionalized α-amino acid. Biological evaluation of synthesized compounds was carried out in vitro for their antimicrobial and antifungal properties against human pathogens. The bile acid conjugates 1g, 2g, 2h and 3g indicated 2–fold stronger antimicrobial activity compared to ciprofloxacin. The final products were obtained in both high yield and purity. The prepared conjugated bile acids were characterized by mass spectrometry, infrared spectroscopy and nuclear magnetic resonance proton spectroscopy which are also discussed along with the thin–layer chromatographic properties.