New Molecular Complexes of Glycyrrhizic Acid Monoammonium Salt (Glycyram) with Fluoroquinolone Antibiotics

Aims: The study aimed to search of new molecular complexes of licorice saponin with fluoroquinolone antibiotics and to explore their pharmaceutical potential. Background: Molecular complexation of triterpene glycosides with pharmaceutical substances reduces side effects and therapeutic doses, increases bioavailability and stability, and expands the spectrum of biological activity of drugs. Glycyrrhizic acid is the major triterpene glycoside of licorice. Molecular complexes of monoammonium salt of glycyrrhizic acid (glycyram, GC) with fluoroquinolone antibiotics have not been described. Objectives: This study is devoted to the preparation and analysis of molecular complexes of GC with fluoroquinolones, and investigation of their antimicrobial activity. Methods: Complexation was studied via FT-IR spectroscopy, UV-Vis spectroscopy and mass spectrometry methods. Results: Molecular complexes of GC with fluoroquinolone antibiotics, along with their benzylated derivatives, were obtained for the first time. Conclusion: The complexes composition was defined as 1:1. Intermolecular hydrogen bonds are formed during complexation. In addition, stability constants of 105 М–1 order were calculated. Some complexes are comparable in antimicrobial activity with individual antibiotics ciprofloxacin (CP) and moxifloxacin (Moc) or surpass them in relation to a number of bacteria. These molecular complexes could be potential low-dose drugs with antimicrobial activity.