Synthesis, Evaluation and in silico studies of 1,8-Naphthyridine derivatives against antimicrobial activity.

In present studies a series of novel 1,8-Naphthyridine derivatives (3a-3f) have been synthesized using nalidixic acid as a starting material. The structures of the compounds were supported by FT-IR, 1H NMR and Mass spectral data. All the synthesized compounds have been evaluated in vitro for their antibacterial activities against several strains of microbes using agar dilution method. The synthesized compounds had moderate to good antibacterial activity. Molecular docking studies reveal that 1,8-Naphthyridine scaffold shared structural complimentary with DNA Gyrase B. Further, TOPKAT analysis on Ames mutagenicity model had shown that this class of compounds have least probability of showing toxicity on experimental animal models.

Synthesis, molecular docking and QSAR studies of 2, 4-disubstituted thiazoles as antimicrobial agents.

In present study a series of 2,4-disubstituted thiazole derivatives was synthesized and evaluated for their in vitro antibacterial and antifungal activities against B. subtilis, E. coli, S. aureus, C. albicans and A. niger by tube dilution method. The analysis of antimicrobial activity results indicated that the presence of NO2 and OCH3 groups at para position of phenyl group improved the antimicrobial activity significantly. Molecular docking studies also supported in vitro activity results and showed that NO2 and OCH3 groups containing compounds have greater affinity towards the target glucosamine-6-phosphate synthase. QSAR studies indicated that molecular connectivity index (2χv) and Kier’s shape index (α3) are the key parameters for antimicrobial activity of synthesized thiazole derivatives and can be cosidered as important factors for interaction with target site of different microorganisms. It is pertinent to note that multi-target QSAR models were more effectual in demonstrating the antimicrobial activity than one-target QSAR models.