Molecular Docking Study of Active Diazenyl Scaffolds as Inhibitors of Essential Targets Towards Antimicrobial Drug Discovery

Proteomic identification of metabolic changes in Paracoccidioides brasiliensis induced by a nitroheteroarylchalcone

Aim: To access the metabolic changes caused by a chalcone derivative (LabMol-75) through a proteomic approach. Methods: Proteomic analysis was performed after 9 h of Paracoccidioides brasiliensis yeast (Pb18) cell incubation with the LabMol-75 at MIC. The proteomic findings were validated through in vitro and in silico assays. Results: Exposure to the compound led to the downregulation of proteins associated with glycolysis and gluconeogenesis, β-oxidation, the citrate cycle and the electron transport chain. Conclusion: LabMol-75 caused an energetic imbalance in the fungus metabolism and deep oxidative stress. Additionally, the in silico molecular docking approach pointed to this molecule as a putative competitive inhibitor of DHPS.

Isolation, characterization, anti-MRSA evaluation, and in-silico multi-target anti-microbial validations of actinomycin X2 and actinomycin D produced by novel Streptomyces smyrnaeus UKAQ_23

Streptomyces smyrnaeus UKAQ_23, isolated from the mangrove-sediment, collected from Jubail,Saudi Arabia, exhibited substantial antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA), including non-MRSA Gram-positive test bacteria. The novel isolate, under laboratory-scale conditions, produced the highest yield (561.3 ± 0.3 mg/kg fermented agar) of antimicrobial compounds in modified ISP-4 agar at pH 6.5, temperature 35 °C, inoculum 5% v/w, agar 1.5% w/v, and an incubation period of 7 days. The two major compounds, K₁ and K₂, were isolated from fermented medium and identified as Actinomycin X₂ and Actinomycin D, respectively, based on their structural analysis. The antimicrobial screening showed that Actinomycin X₂ had the highest antimicrobial activity compared to Actinomycin D, and the actinomycins-mixture (X₂:D, 1:1, w/w) against MRSA and non-MRSA Gram-positive test bacteria, at 5 µg/disc concentrations. The MIC of Actinomycin X₂ ranged from 1.56–12.5 µg/ml for non-MRSA and 3.125–12.5 µg/ml for MRSA test bacteria. An in-silico molecular docking demonstrated isoleucyl tRNA synthetase as the most-favored antimicrobial protein target for both actinomycins, X₂ and D, while the penicillin-binding protein-1a, was the least-favorable target-protein. In conclusion, Streptomyces smyrnaeus UKAQ_23 emerged as a promising source of Actinomycin X₂ with the potential to be scaled up for industrial production, which could benefit the pharmaceutical industry.

Novel biologically active polyurea derivatives and its TiO2-doped nanocomposites

A new series of polyurea derivatives and its nanocomposites were synthesised by the solution polycondensation method through the interaction between 4(2-aminothiazol-4-ylbenzylidene)-4-(tert-butyl) cyclohexanone and diisocyanate compound in pyridine. The PU1-3 structure was confirmed using Fourier transform-infrared (FTIR) spectroscopy and characterised by solubility, viscometry, gel permeation chromatography (GPC), and X-ray diffraction (XRD) analysis. In addition, PU1-3 was evaluated by TGA. Polyurea-TiO2nanocomposites were synthesised using the same technique as that of PU1-3 by adding TiO2 as a nanofiller. The thermal properties of PU2TiO2a-d were evaluated by TGA. Moreover, the morphological properties of a selected sample were examined by SEM and TEM. In addition, PU1-3 and PU2TiO2a-d were examined for antimicrobial activity against certain bacteria and fungi. The PU1-3 showed antibacterial activity against some of the tested bacteria and fungi, as did PU2TiO2a-d, which increased with the increase in TiO2 content. Furthermore, molecular docking studies were displayed against all PU1-3 derivatives against two types of proteins. The results show that the increase in the strength of π-H interactions and H-donors contributed to improved binding of PU2 compared to PU1 andPU3. The docking of 1KZN against the tested polymers suggests an increase in the docking score of PU2, then PU1, and PU3, which is in agreement with the antibacterial study.