Synthesis and in vitro antitumor activity of novel naphthyridinone derivatives

8-Geranyloxycarbostyril as a potent 15-LOX-1 inhibitor showed great anti-tumor effects against prostate cancer

Carbostyrils are quinolone derivatives, with possible growth inhibition properties on cancer cells. Unlike many tumors, 15-Lipoxygenase-1 (15-LOX-1) is highly expressed in prostate cancer (PCa) cells and has oncogenic properties. Here, with the hypothesis that 6-, 7- and 8-geranyloxycarbostyril (GQ) have inhibitory properties on 15-LOX-1, their effects were assessed on PCa cells. Their cytotoxic effects were evaluated by MTT assay and mechanism of cell death was investigated using annexin V/PI staining. Finally, the anti-tumor properties of 8-GQ were assessed in immunocompromised C57BL/6 mice bearing human PCa cells. Accordingly, these compounds could effectively inhibit 15-LOX activity in PCa cells. MTT and flow cytometry tests confirmed their toxic effects on PCa cells, with no significant toxicity on normal cells, and apoptosis was the main mechanism of cell death. In vivo results indicated that use of 8-GQ at 50 mg/kg had stronger anti-tumor effects than 5 mg/kg cisplatin, with fewer side effects on normal tissues. Therefore, 8-GQ can be introduced as a potential drug candidate with 15-LOX-1 inhibitory potency, which can be effective in treatment of prostate cancer, and should be considered for further drug screening investigations.

Discovery of 1,8-naphthalidine derivatives as potent anti-hepatic fibrosis agents via repressing PI3K/AKT/Smad and JAK2/STAT3 pathways

Liver fibrosis is one of the most common pathological consequences of chronic liver diseases (CLD). To develop effective antifibrotic strategies, a novel class of 1-(substituted phenyl)-1,8-naphthalidine-3-carboxamide derivatives were designed and synthesized. By means of the collagen type I α 1 (COL1A1)-based screening and cytotoxicity assay in human hepatic stellate cell (HSC) line LX-2, seven compounds were screened out from total 60 derivatives with high inhibitory effect and relatively low cytotoxicity for further COL1A1 mRNA expression analysis. It was found that compound 17f and 19g dose-dependently inhibited the expression of fibrogenic markers, including α-smooth muscle actin (α-SMA), matrix metalloprotein 2 (MMP-2), connective tissue growth factor (CTGF) and transforming growth factor β1 (TGFβ1) on both mRNA and protein levels. Further mechanism studies indicated that they might suppress the hepatic fibrogenesis via inhibiting both PI3K/AKT/Smad and non-Smad JAK2/STAT3 signaling pathways. Furthermore, 19g administration attenuated hepatic histopathological injury and collagen accumulation, and reduced fibrogenesis-associated protein expression in liver tissues of bile duct ligation (BDL) rats, showing significant antifibrotic effect in vivo. These findings identified 1,8-naphthalidine derivatives as potent anti-hepatic fibrosis agents, and provided valuable information for further structure optimization.

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.

Synthesis, DFT, and eco-friendly insecticidal activity of some N-heterocycles derived from 4-((2-oxo-1,2-dihydroquinolin-3-yl)methylene)-2-phenyloxazol-5(4H)-one

A new series of nitrogen heterocycles encompassing a quinoline scaffold such as imidazolone, benzimidazole, triazinone, triazole, and thiazole derivatives was synthesized utilizing the readily obtainable building block synthon, 4-((2-oxo-1,2-dihydroquinolin-3-yl)methylene)-2-phenyloxazol-5(4H)-one (3). It was interesting that the fused heterocycle, pyranoquinoline derivative 15 was successfully synthesized by different routes of reactions. The synthesized compounds were evaluated for their insecticidal activity and compounds 6, 17, and 20 were the most potent against both Mythimna separata and Nilaparvata lugens. The DFT study was performed for the most potent compounds.

Moxifloxacin-isatin Hybrids Tethered by 1,2,3-triazole and their Anticancer Activities

AIMS

To explore more active fluoroquinolone anticancer candidates.

BACKGROUND

Cancer which can affect almost any part of the body, is most striking and deadliest disease. It is estimated that around one in five people globally develop cancer during their lifetime, and approximately 10% people eventually die from this disease, and 18.1 million new cancer cases with 9.6 million deaths occurred in 2018. The anticancer agents play an intriguingly role in fighting against cancer, and above 100 drugs have already been marketed for this purpose. However, the major drawback of current accessible anticancer agents is the low specificity which results in many side effects. Moreover, cancer cells have already generated resistance to almost all available drugs, creating an urgent need to novel anticancer agents with high specificity and great efficiency especially towards drug-resistant cancers. Quinolone and isatin derivatives were reported to possess promising anticancer activity, high specificity, and relatively few side effects. Currently, several quinolone and isatin derivatives such as Voreloxin, Quarfloxin, AT-3639, Semaxanib, Sunitinib and Nintedanib have already been introduced in clinical practice or under evaluations for the treatment of cancer including drug-resistant cancers, revealing their potential as novel anticancer agents. Hybrid molecules have the potential to increase the specificity, improve the efficiency, and overcome the drug resistance, so hybridization is a promising strategy in the drug discovery. Some of the moxifloxacin-isatin hybrids exhibited considerable activity against various cancer cells even drug-resistant cells, so it is conceivable that hybridization of quinolone and isatin moieties may provide novel anticancer candidates. The structure-activity relationships (SARs) demonstrated that the linkers between quinolone and isatin skeletons were critical for the biological activity, and 1,2,3-triazole could exert various noncovalent interactions with biological targets, so introduction of 1,2,3-triazole as the linker between the two moieties may provide more efficient anticancer candidates.

OBJECTIVE

To explore more active fluoroquinolone anticancer candidates and enrich the structureactivity relationships of fluoroquinolone-isatin hybrids.

METHODS

The synthesized moxifloxacin-isatin hybrids 5a-c, 6a-g and 13a-d were assessed for their anticancer activities against liver cancer cells HepG2, breast cancer cells MCF-7, MCF-7/DOX, prostate cancer cells DU-145 and MDR DU-145 by MTT assay. Hybrid 5b was selected for further evaluation of its tubulin polymerization inhibitory activity with combretastatin A-4 as comparison.

RESULT

Most of the synthesized hybrids were active against the tested cancer cell lines, and the most active hybrid 5b (IC50: 31.3-76.8 μM) was more potent than vorinostat (IC50: 96.7->100 μM), demonstrating moxifloxacin-isatin hybrids are potential anticancer candidates.

CONCLUSION

The mechanism study revealed that inhibition of tubulin polymerization is at least one of the mechanisms of action for this kind of hybrids. Other: The structure-activity relationship was summarized for further rational design of more efficient anticancer candidates.

Novel structural hybrids of quinoline and thiazole moieties: Synthesis and evaluation of antibacterial and antifungal activities with molecular modeling studies

One of the best ways to design new biocidal agents is synthesizing hybrid molecules by combining two or more bioactive moieties in a single molecular scaffold. So, new series of quinolines bearing a thiazole moiety were synthesized using thiosemicarbazones 2a-f. Cyclization of 2a-f with ethyl chloroacetate, ethyl 2-chloropropanoate or chloroacetone afforded the corresponding thiazoles 3-5. The antimicrobial activity of the new quinoline derivatives was evaluated. The most of tested compounds revealed potent both of the antibacterial and antifungal activities. Fourfold potency of amphotericin B for the inhibition the growth of the A. fumigatus was displayed by ccompound 5e. The latter compound displayed twofold potency of gentamycin for inhibition the growth of N. gonorrhoeae. Moreover, this compound showed equipotent potency of references drugs for inhibition of the growth of S. flexneri, S. pyogenes, P. vulgaris, A. clavatus, G. candidum and P. marneffei. So, quinolines bearing a thiazole moiety can be suggested as interesting scaffolds for the development both of the novel antibacterial and antifungal agents. Some new derivatives were studied as peptide deformylase enzyme inhibitors. Thiazolidin-4-one derivative 3d and 2,3-dihydrothiazole derivative 5c had shown good PDF inhibition activity, which had been supported by the docking results with highest binding affinity and lowest docking energy score. These results suggested that the most potent compounds might be possible agents as novel bacterial PDF inhibitor.

The In Vitro Anticancer Activity and Potential Mechanism of Action of 1-[(1R,2S)-2-fluorocyclopropyl]Ciprofloxacin-(4-methyl/phenyl/benzyl-3- aryl)-1,2,4-triazole-5(4H)-thione Hybrids

AIM

Development of 1-[(1R, 2S)-2-fluorocyclopropyl]ciprofloxacin-1,2,4-triazole-5(4H)- thione hybrids as potential dual-acting mechanism anticancer agent to overcome the drug resistance.

BACKGROUND

Chemotherapy is an essential tool for the treatment of lung and female breast cancers, and numerous anticancer agents have been launched for this purpose. However, the clinical outcomes of chemotherapy are usually far from satisfactory due to the side effects and resistance to chemotherapeutic drugs. Thus, it is urgent to develop novel anti-lung and anti-breast cancer agents.

OBJECTIVE

The primary objective of this study was to evaluate the potential of bis-isatin scaffolds with alkyl/ether linkers between the two isatin moieties against different human breast cancer cell lines including A549, MCF-7 and their drug-resistant counterparts A549/CDDP, MCF-7/ADM cells.

METHODS

The 1-[(1R, 2S)-2-fluorocyclopropyl]ciprofloxacin-(4-methyl/phenyl/benzyl-3-aryl)-1,2,4- triazole-5(4H)-thione hybrids were screened for their in vitro activity against drug-sensitive lung (A549), breast (MCF-7) and their drug-resistant counterparts A549/CDDP (cisplatin-resistant), MCF- 7/ADM (doxorubicin-resistant) cancer cell lines by MTT assay. The inhibitory activity of these hybrids against topoisomerase II and EGFR was also evaluated to investigate the potential mechanism of action of these hybrids.

RESULTS

The most prominent hybrid 7k (IC50: 37.28-49.05 µM) was comparable to Vorinostat against A549 and A549/CDDP lung cancer cells, and was 2.79-2.94 times more active than Vorinostat against MCF-7 and MCF-7/ADM breast cancer cell lines. Moreover, hybrid 7k (IC50: 8.6 and 16.4 µM) also demonstrated dual inhibition against topoisomerase II and EGFR.

CONCLUSION

The 1-[(1R, 2S)-2-fluorocyclopropyl]ciprofloxacin-1,2,4-triazole-5(4H)-thione hybrids possess equally activity against both drug-sensitive cancer cells and their drug-resistant counterparts, and the majority of them were no inferior to the reference Vorinostat. The mechanistic study revealed that these hybrids could inhibit both topoisomerase II and EGFR, so these hybrids can be developed as dual-acting mechanism anticancer agents.

Quinolone derivatives and their antifungal activities: An overview

More than 300 million people suffer from the incidence of life-threatening invasive fungal infections, resulting in over 1.35 million deaths annually. Currently, the antifungal agents available in clinics are rather limited, and the rapid development of resistance to the existing antifungal drugs has further aggravated mortality. Quinolones possess a broad spectrum of chemotherapeutic properties and demonstrate considerable antifungal activities as well. Various quinolone derivatives have been screened for their antifungal activities, and some of them exhibit excellent potency against both drug-susceptible and drug-resistant fungi. This review aims to outline the recent advances in quinolone derivatives as potential antifungal agents and summarize the structure-activity relationship, to provide insights for the rational design of more active candidates.

A comprehensive review of topoisomerase inhibitors as anticancer agents in the past decade

The topoisomerase enzymes play an important role in DNA metabolism, and searching for enzyme inhibitors is an important target in the search for new anticancer drugs. Discovery of new anticancer chemotherapeutical capable of inhibiting topoisomerase enzymes is highlighted in anticancer research. Therefore, biologists, organic chemists and medicinal chemists all around the world have been identifying, designing, synthesizing and evaluating a variety of novel bioactive molecules targeting topoisomerase. This review summarizes types of topoisomerase inhibitors in the past decade, and divides them into nine classes by structural characteristics, including N-heterocycles compounds, quinone derivatives, flavonoids derivatives, coumarin derivatives, lignan derivatives, polyphenol derivatives, diterpenes derivatives, fatty acids derivatives, and metal complexes. Then we discussed the application prospect and development of these anticancer compounds, as well as concluded parts of their structural-activity relationships. We believe this review would be invaluable in helping to further search potential topoisomerase inhibition as antitumor agent in clinical usage.

Quinoline-triazole hybrids inhibit falcipain-2 and arrest the development ofPlasmodium falciparumat the trophozoite stage

The present study involves development of novel quinoline triazole-containing cysteine protease inhibitors which arrest the development ofP. falciparumat the trophozoite stage.

Fluoroquinolone-isatin hybrids and their biological activities

Hybridization of different pharmacophores from various bioactive substances into a single molecule is the potential weapon to prevent the drug resistance since this strategy can provide new leads with complimentary activities and/or multiple pharmacological targets. Fluoroquinolone and isatin are common pharmacophores, and their derivatives possess various biological activities. Obviously, hybridization of these two pharmacophores into one molecule may result in novel candidates with broader spectrum, higher efficiency, lower toxicity as well as multiple mechanisms of action. Therefore, fluoroquinolone-isatin hybrids have the potential for clinical deployment in the control and eradication of various diseases. This review covers the recent advances of fluoroquinolone-isatin hybrids as potential anti-bacterial, anti-tubercular, anti-viral and anti-cancer agents. The structure-activity relationship is also discussed to pave the way for the further rational development of this kind of hybrids.

Quinolone derivatives and their activities against methicillin-resistant Staphylococcus aureus (MRSA)

Methicillin-resistant Staphylococcus aureus (MRSA) is the most common pathogen both in hospital and community settings, and is capable of causing serious and even fatal infections. Several antibiotics have been approved for the treatment of infections caused by MRSA, but MRSA has already developed resistance to them. More than ever, it's imperative to develop novel, high effective and fast acting anti-MRSA agents. Quinolones are one of the most common antibiotics in clinical practice used to treat various bacterial infections, and some of them displayed excellent in vitro and in vivo anti-MRSA activities, so quinolone derivatives are one of the most promising candidates. This review summarizes the recent developments of quinolone derivatives with potential activity against MRSA, and the structure-activity relationship is also discussed.

Design, synthesis and antimicrobial evaluation of propylene-tethered ciprofloxacin-isatin hybrids

Twelve novel propylene-tethered ciprofloxacin-isatin hybrids 3a-f and 4a-f were designed, synthesized and characterized by MS, HRMS, ¹H NMR and ¹³C NMR. All hybrids were evaluated for their in vitro antimicrobial activities against representative Gram-positive, Gram-negative and mycobacterial pathogens, cytotoxicity in VERO cell line as well as metabolic stability and in vivo pharmacokinetic (PK) properties. The preliminary results indicated that all mono-isatin-ciprofloxacin hybrids exhibited excellent antibacterial activities with MIC ranging from ≤0.03 to 0.5 μg/mL against most of the tested strains. In particular, ciprofloxacin-isatin hybrid 3d was highly potent against all tested Gram-positive and Gram-negative strains including clinically important drug-resistant pathogens, which was comparable to or more potent than the parent ciprofloxacin and reference levofloxacin. Whereas, conjugate 3b (MIC: 0.10 and 0.5 μg/mL) was 4- and 8-fold more active than ciprofloxacin (MIC: 0.78 μg/mL) and rifampicin (MIC: 0.39 μg/mL) against MTB H₃₇Rv, and 4->256 times more potent than the three references ciprofloxacin (MIC: 2.0 μg/mL), rifampicin (MIC: 32 μg/mL) and isoniazid (>128 μg/mL) against MDR-TB. Both hybrid 3b and 3d with low cytotoxicity (CC₅₀: 64 and 256 μg/mL) also showed acceptable metabolic stability and in vivo PK properties, could act as leads for further optimization.

Antiplasmodial and antimalarial activities of quinolone derivatives: An overview

Malaria remains one of the most deadly infectious diseases globally. Considering the growing spread of resistance, development of new and effective antimalarials remains an urgent priority. Quinolones, which are emerged as one of the most important class of antibiotics in the treatment of various bacterial infections, showed potential in vitro antiplasmodial and in vivo antimalarial activities, making them promising candidates for the chemoprophylaxis and treatment of malaria. This review presents the current progresses and applications of quinolone-based derivatives as potential antimalarials to pave the way for the development of new antimalarials.

4-Quinolone derivatives and their activities against Gram positive pathogens

Gram-positive bacteria are responsible for a broad range of infectious diseases, and the emergency and wide spread of drug-resistant Gram-positive pathogens including MRSA and MRSE has caused great concern throughout the world. 4-Quinolones which are exemplified by fluoroquinolones are mainstays of chemotherapy against various bacterial infections including Gram-positive pathogen infections, and their value and role in the treatment of bacterial infections continues to expand. However, the resistance of Gram-positive organisms to 4-quinolones develops rapidly and spreads widely, making them more and more ineffective. To overcome the resistance and reduce the toxicity, numerous of 4-quinolone derivatives were synthesized and screened for their in vitro and in vivo activities against Gram-positive pathogens, and some of them exhibited excellent potency. This review aims to outlines the recent advances made towards the discovery of 4-quinolone-based derivatives as anti-Gram-positive pathogens agents and the critical aspects of design as well as the structure-activity relationship of these derivatives. The enriched SAR paves the way to the further rational development of 4-quinolones with a unique mechanism of action different from that of the currently used drugs to overcome the resistance, well-tolerated and low toxic profiles.

Synthesis and Antitumor Activity of 5-Bromo-7-azaindolin-2-one Derivatives Containing a 2,4-Dimethyl-1H-pyrrole-3-carboxamide Moiety

We report herein the design and synthesis of a series of novel 5-bromo-7-azaindolin-2-one derivatives containing a 2,4-dimethyl-1H-pyrrole-3-carboxamide moiety. These newly synthesized derivatives were evaluated for in vitro activity against selected cancer cell lines by MTT assay. Results revealed that some compounds exhibit broad-spectrum antitumor potency, and the most active compound 23p (IC₅₀: 2.357-3.012 μM) was found more potent than Sunitinib (IC₅₀: 31.594-49.036 μM) against HepG2, A549 and Skov-3, respectively.