Design and synthesis of biquinolone–isoniazid hybrids as a new class of antitubercular and antimicrobial agents

The Structure-Antiproliferative Activity Relationship of Pyridine Derivatives

Pyridine, a compound with a heterocyclic structure, is a key player in medicinal chemistry and drug design. It is widely used as a framework for the design of biologically active molecules and is the second most common heterocycle in FDA-approved drugs. Pyridine is known for its diverse biological activity, including antituberculosis, antitumor, anticoagulant, antiviral, antimalarial, antileishmania, anti-inflammatory, anti-Alzheimer's, antitrypanosomal, antimalarial, vasodilatory, antioxidant, antimicrobial, and antiproliferative effects. This review, spanning from 2022 to 2012, involved the meticulous identification of pyridine derivatives with antiproliferative activity, as indicated by their minimum inhibitory concentration values (IC50) against various cancerous cell lines. The aim was to determine the most favorable structural characteristics for their antiproliferative activity. Using computer programs, we constructed and calculated the molecular descriptors and analyzed the electrostatic potential maps of the selected pyridine derivatives. The study found that the presence and positions of the -OMe, -OH, -C=O, and NH2 groups in the pyridine derivatives enhanced their antiproliferative activity over the cancerous cellular lines studied. Conversely, pyridine derivatives with halogen atoms or bulky groups in their structures exhibited lower antiproliferative activity.

1,2,4‐Triazole and benzimidazole fused dihydropyrimidine derivatives: Design, green synthesis, antibacterial, antitubercular, and antimalarial activities

This study reports the design and synthesis of novel 1,2,4-triazolo/benzimidazolo-pyrimidine linked 1-benzyl-4-[(p-tolyloxy)methyl]-1,2,3-triazole derivatives as potent antimicrobial agents according to their in vitro antibacterial, antifungal, antitubercular as well as antimalarial activities. An efficient, ecologically benign, and facile multicomponent synthesis was employed to synthesize these derivatives. The synthesis is accelerated with the mild and eco-friendly organocatalyst tetrabutylammonium bromide, providing a yield of 82%-96% within the short reaction time of 0.5-1.5 h. Compared with the MIC values of ciprofloxacin and ampicillin on the respective strains, compound d2 showed better activity against Escherichia coli and Streptococcus pyogenes and compound d8 showed better MIC against Staphylococcus aureus. Additionally, compounds d3, d4, and d5 showed potent MIC values against Pseudomonas aeruginosa. All triazolo-pyrimidine derivatives d1-d8 showed potent inhibitory action against Gram-positive strains. Compound e3 showed good potency against Mycobacterium tuberculosis H37Rv. The IC₅₀ values of d3 and e2 indicated better activity against Plasmodium falciparum. Collectively, these derivatives depict potent multifaceted activity and provide promising access for further antimicrobial and antimalarial investigations.

Pyrazinamide–isoniazid hybrid: synthesis optimisation, characterisation, and antituberculous activity

Over time, the effective resistance mechanisms to various first- and second-line drugs against the disease of tuberculosis make its treatment extremely difficult. This work presents a new approach to synthesizing a hybrid of antituberculosis medications: isoniazid (INH) and pyrazinamide (PZA). The synthesis was performed using ultrasound-assisted synthesis to obtain an overall yield of 70%, minimizing the reaction time from 7 to 1 h. The evaluation of the biological activity of the hybrid (compound 2) was tested using the tetrazolium microplate assay (TEMA), showing inhibition in the growth of Mycobacterium tuberculosis H37Rv at a concentration of 0.025 mM at pH 6.0 and 6.7.

Antimicrobial and cytotoxic activities of isoniazid connected menthone derivatives and their investigation of clinical pathogens causing infectious disease

BACKGROUND

This work is development of new molecules of isoniazid derivatives as dealing with potential of antimicrobial activity against clinical pathogens causing infectious disease. Antimicrobial of novel Mannich base derivatives can be achieved via one-pot synthesis in green chemistry approach. This method offers efficient, mild reaction conditions and high yields. In this study, totally 12 compounds (1a-l) was prepared and screened for cytotoxic and antimicrobial activities.

MATERIALS AND METHODS

Newly synthesised compounds were conformed via FT- IR, ¹H, and ¹³C NMR (Nuclear Magnetic Resonance), and mass spectra analysis. All compounds were checked antibacterial activity against gram-positive bacteria of Enterococcus faecalis, Staphylococcus aureus and gram-negative bacteria of Pseudomonas aeruginosa, Klebsiella pneumoniae and Escherichia coli. All compounds were checked against antifungal activity against Aspergillus fumigatus, Candida albicans, Cryptococcus neoformans, Aspergillus niger, and Microsporum audouinii. All compounds were screened for cytotoxic activity against the MCF-7 (Michigan Cancer Foundation-7) cancer cell line.

RESULT

The compound 1g was highly (MIC: 0.25 μg/mL) active against gram-negative bacterial of P. aeruginosa, whereas other compounds 1e and 1h were more active (MIC: 2 μg/mL) in K. pneumoniae and also 1g (MIC: 2 μg/mL) was more active in E. faecalis than standard ciprofloxacin. Antifungal screening, the compound 1b was highly active (MIC: 0.25 μg/mL) against C. albicance,1g (MIC: 2 μg/mL) and 1h (MIC: 4 μg/mL) was significant of active against A. fumigatus, and the compound 1c (MIC: 4 μg/mL) was extremely active in M. audouinii than clotrimazole. Compound 1g (GI₅₀ = 0.01 μM) exhibited high activity against the MCF-7 cell line, while 1b (GI₅₀ = 0.02 μM) was equipotent active compared with standard doxorubicin.

CONCLUSION

A novel set of isoniazid derivatives (1a-l) and 1h were synthesized and screened for antimicrobial and cytotoxic activities. We found some highly active molecules, which are evidencing to be a potential treatment of bacterial and fungal infection candidates.

Microwave-Assisted Synthesis of Schiff Bases of Isoniazid and Evaluation of Their Anti-Proliferative and Antibacterial Activities

Three new Schiff bases of isoniazid were synthesized using microwave-assisted synthesis and conventional condensation with aromatic aldehydes. Synthesized compounds were characterized using elemental analysis, IR, NMR, and Mass spectroscopy. Synthesized compounds were evaluated for antiproliferative activity against MCF-7 cell line. The IC50 values were from 125 to 276 µM. The compounds were also evaluated for antibacterial activity against Staphylococcus aureus and Escherichia coli. Results showed that the synthesized compounds produce significant antibacterial activity in vitro. Inhibition of compounds ranged from 13 to 18 mm.

Recent Synthetic Approaches and Biological Evaluations of Amino Hexahydroquinolines and Their Spirocyclic Structures

In this review, the recent synthetic approaches of amino hexahydroquinolines and their spirocyclic structures were highlighted. The synthetic routes include, two-components, three-components or fourcomponents reactions. The two-component [3+3] atom combination reaction represents the simplest method. It involves Michael addition of the electron rich β-carbon of β-enaminones to the activated double bond of cinnamonitriles followed by cyclization to yield hexahydroquinoline compounds. The bioactivity profiles and SAR studies of these compounds were also reviewed with emphasis to the utility of these substances as antimicrobial, anticancer and antitubercular agents, as well as calcium channel modulators.

Ciprofloxacin derivatives and their antibacterial activities

Bacterial infections represent a significant health threat globally, and are responsible for the majority of hospital-acquired infections, leading to extensive mortality and burden on global healthcare systems. The second generation fluoroquinolone ciprofloxacin which exhibits excellent antimicrobial activity and pharmacokinetic properties as well as few side effects is introduced into clinical practice for the treatment of various bacterial infections for around 3 decades. The emergency and widely spread of drug-resistant pathogens making ciprofloxacin more and more ineffective, so it's imperative to develop novel antibacterials. Numerous of ciprofloxacin derivatives have been synthesized for seeking for new antibacterials, and some of them exhibited promising potency. This review aims to summarize the recent advances made towards the discovery of ciprofloxacin derivatives as antibacterial agents and the structure-activity relationship of these derivatives was also discussed.

Microwave assisted one-pot synthetic route to imidazo[1,2-a]pyrimidine derivatives of imidazo/triazole clubbed pyrazole and their pharmacological screening

An efficient synthetic microwave-assisted, one-pot three-component condensation route for imidazo[1,2-a]pyrimidine derivatives of imidazole 4/triazole 5 clubbed pyrazole catalysed by ecofriendly base KOH.

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.

Hybrid molecules: The privileged scaffolds for various pharmaceuticals

The practice of polypharmacology is not a new concept but the approaches which are being adopted for administering the two or more drugs together are varied from time to time. Taking two or more drugs simultaneously, co-formulation of two or more active agents in a single tablet and development of hybrid molecular entities capable to modulate multiple targets are the three popular approaches for multidrug therapy. The simultaneous use of more than one drug for the chemotherapy of a single disease demands a lot of patient compliance. Hence the present form of polypharmacology is gaining popularity in the form of hybrid molecules (multiple ligand approach). From the last 1-2 decades, the synthesis of hybrid molecules by the combination of different biologically relevant moieties has been under constant escalation along with their evaluation as diverse range of pharmacological agents and as potent drugs. This review is focused on the biological potential of hybrid molecules with particular mention of those exhibiting anti-fungal, anti-tuberculosis, anti-malarial, anti-inflammatory and anti-cancer activities. A comparison of the drug potency of the hybrid molecules with their individual counterparts is discussed for quantifying the significance of the concept of molecular hybridisation.

Synthesis and docking studies of pyrazine-thiazolidinone hybrid scaffold targeting dormant tuberculosis

The persistence of Mycobacterium tuberculosis (MTB) in dormant stage assists the pathogen to develop resistance against current antimycobactrial drugs. To address this issue, we report herein the synthesis of N-(4-oxo-2 substituted thiazolidin-3 yl) pyrazine-2-carbohydrazide derivatives designed by following the molecular hybridization approach using pyrazine and thiazolidenone scaffolds. The compounds were evaluated against MTB H37Ra and Mycobacterium bovis BCG in dormancy model. Most of the compounds had IC50 values in 0.3-1 μg/ml range. The active compounds were further tested for anti-proliferative activity against THP-1, Panc-1, A549, and MCF-7 cell lines using MTT assay and exhibited no significant cytotoxicity. We also report molecular docking studies using active analogs and MTB - Decaprenylphosphoryl-β-d-ribose-2'-epimerase (DprE1) to rationalize the biological activity and to provide an insight into the probable mechanism of action and binding mode of hybridized structures. The results obtained validate the use of molecular hybridization approach and also suggest that reported compounds can provide a novel pharmacophore to synthesize lead compounds against dormat MTB.

Studies on antimicrobial effects of four ligands and their transition metal complexes with 8-mercaptoquinoline and pyridine terminal groups

Four types of ligands (Q1-Q4) and their complexes (1-36) with transition metal ions have been synthesized, in which two new complexes (15 and 20) have been prepared and tested. In vitro antimicrobial activities of the ligands and their complexes were investigated against a representative panel of strains including two Gram positive bacteria (Sarcina ureae, Staphylococcus aureus), two Gram negative bacteria (Escherichia coli, Pseudomonas aeruginosa) and three fungi (Aspergillus niger, Saccharomyces cerevisiae, Fusarium oxysporum f. sp. cubense). The relationship between the structure and the antibacterial activities was discussed. Our study results indicated that some compounds have preferred antibacterial activities that may have potential pharmaceutical applications.

Novel 1,3,4-oxadiazole motifs bearing a quinoline nucleus: synthesis, characterization and biological evaluation of their antimicrobial, antitubercular, antimalarial and cytotoxic activities

Quinoline–oxadiazole hybrids: a new class of antimicrobial, antitubercular and antimalarial compounds.