Increased antibacterial activity of DW286, a novel fluoronaphthyridone antibiotic, against Staphylococcus aureus strains with defined mutations in DNA gyrase and topoisomerase IV

Exploring fluorine-substituted piperidines as potential therapeutics for diabetes mellitus and Alzheimer's diseases

In the current study, a series of fluorine-substituted piperidine derivatives (1-8) has been synthesized and characterized by various spectroscopic techniques. In vitro and in vivo enzyme inhibitory studies were conducted to elucidate the efficacy of these compounds, shedding light on their potential therapeutic applications. To the best of our knowledge, for the first time, these heterocyclic structures have been investigated against α-glucosidase and cholinesterase enzymes. The antioxidant activity of the synthesized compounds was also assessed. Evaluation of synthesized compounds revealed notable inhibitory effects on α-glucosidase and cholinesterases. Remarkably, the target compounds (1-8) exhibited extraordinary α-glucosidase inhibitory activity as compared to the standard acarbose by several-fold. Subsequently, the potential antidiabetic effects of compounds 2, 4, 5, and 6 were validated using a STZ-induced diabetic rat model. Kinetic studies were also performed to understand the mechanism of inhibition, while structure-activity relationship analyses provided valuable insights into the structural features governing enzyme inhibition. Kinetic investigations revealed that compound 4 displayed a competitive mode of inhibition against α-glucosidase, whereas compound 2 demonstrated mixed-type behavior against AChE. To delve deeper into the binding interactions between the synthesized compounds and their respective enzyme targets, molecular docking studies were conducted. Overall, our findings highlight the promising potential of these densely substituted piperidines as multifunctional agents for the treatment of diseases associated with dysregulated glucose metabolism and cholinergic dysfunction.

In Vitro and In Vivo Activity of Zabofloxacin and Other Fluoroquinolones Against MRSA Isolates from A University Hospital in Egypt

The widespread of infections caused by methicillin-resistant Staphylococcus aureus (MRSA), has necessitated the search for alternative therapies; introduction of new agents being a suggestion. This study compares the in vitro and in vivo activities of zabofloxacin, a novel fluoroquinolone, with moxifloxacin, levofloxacin and ciprofloxacin against clinical isolates of MRSA from patients hospitalized in the Alexandria Main University hospital; a tertiary hospital in Alexandria, Egypt, where zabofloxacin has not been yet introduced. The strains tested showed the highest percentage of susceptibility to zabofloxacin (61.2%) among the tested fluoroquinolones with the most effective MIC₅₀ and MIC₉₀ (0.25 and 2 µg/ml, respectively). Time-kill curve analysis revealed a rapid bactericidal activity of zabofloxacin after 6 h of incubation with a quinolone-resistant isolate and complete killing when tested against a quinolone-sensitive isolate with inhibition of regrowth in both cases. PCR amplification and sequencing of QRDRs in selected strains revealed the following amino acid substitutions: Ser-84→Leu in GyrA, Ser-80→Phe in GrlA and Pro-451→Ser in GrlB. The in vivo studies demonstrated that zabofloxacin possessed the most potent protective effect against systemic infection in mice (ED50: 29.05 mg/kg) with lowest count in the dissected lungs (3.66 log₁₀ CFU/ml). The histopathological examination of lung specimens of mice treated with zabofloxacin displayed least congestion, inflammation, oedema and necrosis with clear alveolar spaces and normal vessels. In conclusion, zabofloxacin was proved to possess high in vitro and in vivo efficacy encompassing its comparators and could be considered as a possible candidate for the treatment of infections caused by MRSA. To our knowledge, this is the first study evaluating the in vitro and in vivo activity of zabofloxacin against Egyptian MRSA clinical isolates.

Antimicrobial activity of DW286 against Streptococcus pneumoniae

DW286 is a novel broad-spectrum fluoroquinolone with excellent antipneumococcal activity. The in vitro activity of DW286 was evaluated against quinolone-susceptible and -resistant Streptococcus pneumoniae and was compared with the activities of reference compounds. Among the tested agents, DW286 showed the most potent antibacterial activity against 94 quinolone-susceptible strains [minimum inhibitory concentration (MIC) 0.008-0.03 mg/L]. Against 23 quinolone-resistant S. pneumoniae with known resistance mechanisms, DW286 also had the lowest MICs of all the tested quinolones [MIC at which 90% of isolates were inhibited (MIC(90))=0.5mg/L], followed by ciprofloxacin, sparfloxacin, moxifloxacin and gemifloxacin. The in vivo activity of DW286 against penicillin-susceptible and -resistant S. pneumoniae was more effective than that of gemifloxacin.