Synthesis and biological evaluation of novel fused indolo [3, 2-c] [1,8] naphthyridine derivatives as potential antibacterial agents

Antioxidant and Antimicrobial Potential of 1,8-Naphthyridine Based Scaffolds: Design, Synthesis and in Silico Simulation Studies within Topoisomerase II

A series of spiro β-Lactams (4 a-c, 7 a-c) and thiazolidinones (5 a-c, 8 a-c) possessing 1,8-naphthyridine moiety were synthesized in this study. The structure of the newly synthesized compounds has been confirmed by IR, 1H-NMR, 13C NMR, mass spectra, and elemental analysis. The synthesized compounds were tested in vitro for their antibacterial and antifungal activity against various strains. The antimicrobial data showed that most of the compounds displayed good efficacy against both bacteria and fungi. The structure-activity relationship (SAR) studies suggested that the presence of electron-withdrawing chloro (3 b, 4 b, and 5 b) and nitro groups (7 b, 8 b) at the para position of the phenyl ring improved the antimicrobial activity of the compounds. The free radical scavenging assay showed that all the synthesized compounds exhibited significant antioxidant activity on DPPH. Compounds 8 b (IC50=17.68±0.76 μg/mL) and 4 c (IC50=18.53±0.52 μg/mL) showed the highest antioxidant activity compared to ascorbic acid (IC50=15.16±0.43 μg/mL). Molecular docking studies were also conducted to support the antimicrobial and SAR results.

Pyrazole derivatives of pyridine and naphthyridine as proapoptotic agents in cervical and breast cancer cells

Cancer is one of the leading causes of death worldwide. The increasing prevalence and resistance to chemotherapy is responsible for driving the search of novel molecules to combat this disease. In search of novel compounds with pro-apoptotic potential, pyrazolo-pyridine and pyrazolo-naphthyridine derivatives were investigated against cervical cancer (HeLa) and breast cancer (MCF-7) cells. The anti-proliferative activity was determined through the MTT assay. Potent compounds were then analyzed for their cytotoxic and apoptotic activity through a lactate dehydrogenase assay and fluorescence microscopy after propidium iodide and DAPI staining. Flow cytometry was used to determine cell cycle arrest in treated cells and pro-apoptotic effect was verified through measurement of mitochondrial membrane potential and activation of caspases. Compounds 5j and 5k were found to be most active against HeLa and MCF-7 cells, respectively. G0/G1 cell cycle arrest was observed in treated cancer cells. Morphological features of apoptosis were also confirmed, and an increased oxidative stress indicated the involvement of reactive oxygen species in apoptosis. The compound-DNA interaction studies demonstrated an intercalative mode of binding and the comet assay confirmed the DNA damaging effects. Finally, potent compounds demonstrated a decrease in mitochondrial membrane potential and increased levels of activated caspase-9 and -3/7 confirmed the induction of apoptosis in treated HeLa and MCF-7 cells. The present work concludes that the active compounds 5j and 5k may be used as lead candidates for the development of lead drug molecules against cervical and breast cancer.

1,8-Naphthyridine Derivatives: A Privileged Scaffold for Versatile Biological Activities

1, 8- Naphthyridine nucleus belongs to significant nitrogen-containing heterocyclic compounds which has garnered the interest of researchers due to its versatile biological activities. It is known to be used as an antimicrobial, anti-psychotic, anti-depressant, anti-convulsant, anti- Alzheimer's, anti-cancer, analgesic, anti-inflammatory, antioxidant, anti-viral, anti-hypertensive, antimalarial, pesticides, anti-platelets, and CB2 receptor agonist, etc. The present review highlights the framework of biological properties of synthesized 1, 8-naphthyridine derivatives developed by various research groups across the globe.

1,8-naphthyridine derivatives: an updated review on recent advancements of their myriad biological activities

Among all nitrogen-containing heterocycles, the 1,8-naphthyridine scaffold has recently gained an immense amount of curiosity from numerous researchers across fields of medicinal chemistry and drug discovery. This new attention can be ascribed to its versatility of synthesis, its reactiveness and the variety of biological activities it has exhibited. Over the past half-decade, numerous diverse biological evaluations have been conducted on 1,8-naphthyridine and its derivatives in a quest to unravel novel pharmacological facets to this scaffold. Its potency to treat neurodegenerative and immunomodulatory disorders, along with its anti-HIV, antidepressant and antioxidant properties, has enticed researchers to look beyond its broad-spectrum activities, providing further scope for exploration. This review is a consolidated update of previous works on 1,8-naphthyridines and their analogs, focusing on the past 5 years.

Indole/isatin-containing hybrids as potential antibacterial agents

The emergence and worldwide spread of drug-resistant bacteria have already posed a serious threat to human life, creating the urgent need to develop potent and novel antibacterial drug candidates with high efficacy. Indole and isatin (indole-2,3-dione) present a wide structural and mechanistic diversity, so their derivatives possess various pharmacological properties and occupy a salient place in the development of new drugs. Indole/isatin-containing hybrids, which demonstrate a promising activity against a panel of clinically important Gram-positive and Gram-negative bacteria, are privileged scaffolds for the discovery of novel antibacterial candidates. This review, covering articles published between January 2015 and May 2020, focuses on the development and structure-activity relationship (SAR) of indole/isatin-containing hybrids with potential application for fighting bacterial infections, to facilitate further rational design of novel drug candidates.