Design, synthesis, in vitro and in silico evaluation of novel substituted 1,2,4-triazole analogues as dual human VEGFR-2 and TB-InhA inhibitors

Cancer is a leading cause of death globally and has been associated with Mycobacterium tuberculosis (Mtb). The angiogenesis-related VEGFR-2 is a common target between cancer and Mtb. Here, we aimed to synthesize and validate potent dual human VEGFR-2 inhibitors as anticancer and anti-mycobacterial agents. Two series of 1,2,4-triazole-based compounds (6a-l and 11a-e) were designed and synthesized through a molecular hybridization approach. Activities of all synthesized compounds were evaluated against human VEGFR-2 in addition to drug-sensitive, multidrug-resistant and extensive-drug resistant Mtb. Compounds 6a, 6c, 6e, 6f, 6h, 6l, 11a, 11d and 11e showed promising inhibitory effect on VEGFR-2 (IC50 = 0.15 - 0.39 µM), anti-proliferative activities against cancerous cells and low cytotoxicity against normal cells. The most potent compounds (6e and 11a) increased apoptosis percentage. Additionally, compounds 6h, 6i, 6l and 11c showed the highest activities against all Mtb strains, and thus were evaluated against enoyl-acyl carrier protein reductase (InhA) which is essential for Mtb cell wall synthesis. Interestingly, the compounds showed excellent InhA inhibition activities with IC50 range of 1.3 - 4.7 µM. Docking study revealed high binding affinities toward targeted enzymes; human VEGFR-2 and Mtb InhA. In conclusion, 1,2,4-triazole analogues are suggested as potent anticancer and antimycobacterial agents via inhibition of human VEGFR-2 and Mtb InhA.

Targeting Mycobacterium tuberculosis: Synthesis, in vitro and in silico evaluation of novel N1 -(benzo[d]oxazol-2-yl)-N4 -arylidine compounds

The development of novel antimycobacterial agents is an urgent challenge to eradicate the increasing emergence and rapid spread of multidrug-resistant strains. Filamentous temperature-sensitive protein Z (FtsZ) is a crucial cell division protein. Alteration of FtsZ assembly leads to cell division inhibition and cell death. To find novel antimycobacterial agents, a series of N¹ -(benzo[d]oxazol-2-yl)-N⁴ -arylidine compounds 5a-o were synthesized. The activity of the compounds was evaluated against drug-sensitive, multidrug-resistant, and extensive-drug-resistant Mycobacterium tuberculosis. Compounds 5b, 5c, 5l, 5m, and 5o showed promising antimycobacterial activity with minimum inhibitory concentrations (MIC) in the range of 0.48-1.85 µg/mL and with low cytotoxicity against human nontumorigenic lung fibroblast WI-38 cells. The activity of the compounds 5b, 5c, 5l, 5m, and 5o was evaluated against bronchitis causing-bacteria. They exhibited good activity against Streptococcus pneumoniae, Klebsiella pneumoniae, Mycoplasma pneumonia, and Bordetella pertussis. Molecular dynamics simulations of Mtb FtsZ protein-ligand complexes identified the interdomain site as the binding site and key interactions. ADME prediction indicated that the synthesized compounds have drug-likeness. The density function theory studies of 5c, 5l, and 5n were performed to investigate E/Z isomerization. Compounds 5c and 5l are present as E-isomers and 5n as an E/Z mixture. Our experimental outcomes provide an auspicious lead for the design of more selective and potent antimycobacterial drugs.

Synthesis and anticancer activity of novel quinazolinone-based rhodanines

Background

Rhodanines and quinazolinones have been reported to possess various pharmacological activities.

Results

A novel series of twenty quinazolinone-based rhodanines were synthesized via Knoevenagel condensation between 4-[3-(substitutedphenyl)-3,4-dihydro-4-oxoquinazolin-2-yl)methoxy]substituted-benzaldehydes and rhodanine. Elemental and spectral analysis were used to confirm structures of the newly synthesized compounds. The newly synthesized compounds were biologically evaluated for in vitro cytotoxic activity against the human fibrosarcoma cell line HT-1080 as a preliminary screen using the MTT assay.

Conclusions

All the target compounds were active, displaying IC₅₀ values roughly in the range of 10–60 µM. Structure–activity relationship study revealed that bulky, hydrophobic, and electron withdrawing substituents at the para-position of the quinazolinone 3-phenyl ring as well as methoxy substitution on the central benzene ring, enhance cytotoxic activity. The four most cytotoxic compounds namely, 45, 43, 47, and 37 were further tested against two human leukemia cell lines namely, HL-60 and K-562 and showed cytotoxic activity in the low micromolar range with compound 45 being the most active, having IC₅₀ values of 1.2 and 1.5 μM, respectively. Interestingly, all four compounds were devoid of cytotoxicity against normal human fibroblasts strain AG01523, indicating that the synthesized rhodanines may be selectively toxic against cancer cells. Mechanistic studies revealed that the most cytotoxic target compounds exhibit pro-apoptotic activity and trigger oxidative stress in cancer cells.

Hydrazones of 2-aryl-quinoline-4-carboxylic acid hydrazides: synthesis and preliminary evaluation as antimicrobial agents

A new series of 2-arylquinoline-4-carboxylic acid hydrazide-hydrazones was synthesized using an appropriate synthetic route. All the target compounds were evaluated for their in vitro antimicrobial activity against Staphylococcus aureus as an example for Gram-positive bacteria, Escherichia coli as an example for Gram-negative bacteria, and Candida albicans as a representative of fungi. The minimum inhibitory concentration (MIC) was determined for test compounds as well as for reference standards. Among the compounds tested, compounds having nitro substituents at the arylidene moiety showed the most potent antifungal as well as antibacterial activities against E. coli. Compound 23 displayed an antifungal activity comparable to that of nystatin. However, none of the compounds demonstrated any antibacterial activity against S. aureus. Hydrophobicity of the target compounds correlated weakly with their antibacterial and antifungal activities. The most potent compounds namely, 7, 18, 19, 22, and 23 were assessed for hemolytic toxicity and found to be non-hemolytic up to a concentration of 100mug/mL. In addition, the most potent compound (23) was evaluated for in vitro cytotoxic activity against various cancer cell lines. This compound was found to display no cytotoxic activity but rather it induces the proliferation rate of Hep-G2 cells.