Synthesis, characterization, antibacterial, antifungal, and immunomodulating activities of gatifloxacin derivatives

Gatifloxacin is a synthetic broad-spectrum fluorquinolone antibacterial agent with a 3-methylpiperazinyl-side chain at position 7 and a methoxy group at position 8 of the quinolone ring. In the present study different analogues of gatifloxacin were prepared; the piperazinyl ring was chosen as the center of reaction for synthesizing this series of derivatives. The structures of these derivatives were established using spectroscopic techniques such as IR, 1H NMR, and EIMS. In vitro antibacterial and antifungal activities were evaluated by disc diffusion method and these derivatives were compared with in-use fluoroquinolones like gatifloxacin, sparfloxacin, and gemifloxacin. Derivative A proved very potent against Gram-negative organisms, especially Pseudomonas aeruginosa, Shigella flexeneri, and Klebseilla pneumoniae, and derivatives A–C exhibited good antifungal activity compared to in-use quinolones. In addition, gatifloxacin and derivatives were investigated for immunomodulating activities. Derivative B has good anti-inflammatory activity, with IC50 < 12.5 μg/ml.