Antibacterial and molecular docking studies of newly synthesized nucleosides and Schiff bases derived from sulfadimidines

Catalytic degradation of rhodamine blue and bactericidal action of AgBr and chitosan-doped CuFe2O4 nanostrucutres evidential molecular docking analysis

The harmful cationic dyes present in industrial waste significantly decrease the effectiveness of remedy operations. Considering the horrendous impact of these dyes on the environment and biodiversity, silver bromide (AgBr) and chitosan (CS) doped copper ferrite (CuFe2O4) nanostructures (NSs) were prepared by the co-precipitation route. In this work, The surface characteristics of CuFe2O4 can be altered by CS, potentially enhancing its catalytic reaction compatibility. The functional groups in CS interact with the surface of CuFe2O4, influencing its catalytic behavior. AgBr can have an impact on the dynamics of charge carriers in the composite. Better charge separation and transfer which is essential for catalytic processes. The catalytic degradation of RhB was significantly enhanced (100 %) using 4 wt% of AgBr-doped CS-CuFe2O4 catalysts in a basic medium. The significant inhibitory zones (9.25 to 17.95 mm) inhibitory in maximum doses were seen against Gram-positive bacteria (S. aureus). The bactericidal action of AgBr/CS-doped CuFe2O4 NSs against DNA gyraseS.aureus and tyrosyl-tRNAsynthetase S. aureus was rationalized using molecular docking studies, which supported their function as inhibitors.

Antimicrobial, antioxidant and cytotoxic activities of the leaf and stem extracts of Carissa bispinosa used for dental health care

BACKGROUND

Carissa bispinosa (L.) Desf. ex Brenan is one of the plants used traditionally to treat oral infections. However, there is limited data validating its therapeutic properties and photochemistry. The aim of this study was to investigate the protective efficacy of the leaf and stem extracts of C. bispinosa against oral infections.

METHODS

The phenolic and tannin contents were measured using Folin-Ciocalteau method after extracting with different solvents. The minimum inhibitory concentrations (MIC) of the extracts were assessed using the microdilution method against fungal (Candida albicans and Candida glabrata) and bacterial (Streptococcus pyogenes, Staphylococcus aureus and Enterococcus faecalis) strains. The 2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing power (FRP) models were utilised to assess the antioxidant potential of the extracts. Cytotoxicity of the leaf acetone extract was evaluated using the methylthiazol tetrazolium assay.

RESULTS

The methanol leaf extract had the highest phenolic content (113.20 mg TAE/g), whereas hexane extract displayed the highest tannin composition of 22.98 mg GAE/g. The acetone stem extract had the highest phenolic content (338 mg TAE/g) and the stem extract yielded the highest total tannin content (49.87 mg GAE/g). The methanol leaf extract demonstrated the lowest MIC value (0.31 mg/mL), whereas the stem ethanol extract had the least MIC value of 0.31 mg/mL. The stem methanol extract had the best DPPH free radical scavenging activity (IC50, 72 µg/mL) whereas the stem ethanol extract displayed maximum FRP with absorbance of 1.916. The leaf acetone extract had minimum cytotoxicity with the lethal concentration (LC50) of 0.63 mg/mL.

CONCLUSIONS

The results obtained in this study validated the protective effect of C. bispinosa against oral infections.

Evaluation of Antimicrobial Activity by Marine Nocardiopsis dassonvillei against Foodborne Listeria monocytogenes and Shiga Toxin-Producing Escherichia coli

The emergence of multidrug-resistant pathogens creates public health challenges, prompting a continuous search for effective novel antimicrobials. This study aimed to isolate marine actinomycetes from South Africa, evaluate their in vitro antimicrobial activity against Listeria monocytogenes and Shiga toxin-producing Escherichia coli, and characterize their mechanisms of action. Marine actinomycetes were isolated and identified by 16S rRNA sequencing. Gas chromatography-mass spectrometry (GC-MS) was used to identify the chemical constituents of bioactive actinomycetes' secondary metabolites. Antibacterial activity of the secondary metabolites was assessed by the broth microdilution method, and their mode of actions were predicted using computational docking. While five strains showed antibacterial activity during primary screening, only Nocardiopsis dassonvillei strain SOD(B)ST2SA2 exhibited activity during secondary screening for antibacterial activity. GC-MS identified five major bioactive compounds: 1-octadecene, diethyl phthalate, pentadecanoic acid, 6-octadecenoic acid, and trifluoroacetoxy hexadecane. SOD(B)ST2SA2's extract demonstrated minimum inhibitory concentration and minimum bactericidal concentration, ranging from 0.78-25 mg/mL and 3.13 to > 25 mg/mL, respectively. Diethyl phthalate displayed the lowest bacterial protein-binding energies (kcal/mol): -7.2, dihydrofolate reductase; -6.0, DNA gyrase B; and -5.8, D-alanine:D-alanine ligase. Thus, marine N. dassonvillei SOD(B)ST2SA2 is a potentially good source of antibacterial compounds that can be used to control STEC and Listeria monocytogenes.

An insight into the cytotoxic, antimicrobial, antioxidant, and biocontrol perspective of novel Iron(III) complexes of substituted benzimidazoles: Inhibition kinetics and molecular simulations

Mononuclear complexes [FeCl3L2(OH2)] (L = L1, L2) were designed and synthesized by combining FeCl3 with 2-(3'-Aminophenylbenzimidazole) (L1) and 2-[(3'-N-Salicylidinephenyl)benzimidazole] (L2) and were characterized by physico-analytical strategies. The redox properties of the complexes were disclosed by the cyclic voltammetric method. Further, the interactions of complexes with proteins were studied by performing molecular docking engaging protein models of common cancer therapeutic targets to foresee their affinity to bind to these proteins. The complexes evidenced better protein-ligand docking (-8.4 and -9.0 kcal mol-1) and higher binding energies than their ligands. However, the L1 complex displayed improved binding free energy (-33.576 ± 1.01 kcal mol-1) compared to the other complexes and individual ligands. These compounds were screened for in vitro cytotoxic assays against triple-negative breast cancer cell lines (MDA-MB-468 cells), anti-inflammatory, antimicrobial, and antioxidant properties. The in vitro study complemented the in silico assay; therefore, these compounds may be a viable choice for expanding anticancer therapy. Additionally, the L2 showed better biocontrol activity owing to the enhanced growth of Trichoderma and inhibited the growth of Fusarium oxysporum.Communicated by Ramaswamy H. Sarma.

Comparative molecular docking and toxicity between carbon-capped metal oxide nanoparticles and standard drugs in cancer and bacterial infections

Introduction

Nanoparticles (NPs) are of great interest in the design of various drugs due to their high surface-to-volume ratio, which result from their unique physicochemical properties. Because of the importance of examining the interactions between newly designed particles with different targets in the case of various diseases, techniques for examining the interactions between these particles with different targets, many of which are proteins, are now very common.

Methods

In this study, the interactions between metal oxide nanoparticles (MONPs) covered with a carbon layer (Ag2O3, CdO, CuO, Fe2O3, FeO, MgO, MnO, and ZnO NPs) and standard drugs related to the targets of Cancer and bacterial infections were investigated using the molecular docking technique with AutoDock 4.2.6 software tool. Finally, the PRO TOX-II online tool was used to compare the toxicity (LD50) and molecular weight of these MONPs to standard drugs.

Results

According to the data obtained from the semi flexible molecular docking process, MgO and Fe2O3 NPs performed better than standard drugs in several cases. MONPs typically have a lower 50% lethal dose (LD50) and a higher molecular weight than standard drugs. MONPs have shown a minor difference in binding energy for different targets in three diseases, which probably can be attributed to the specific physicochemical and pharmacophoric properties of MONPs.

Conclusion

The toxicity of MONPs is one of the major challenges in the development of drugs based on them. According to the results of these molecular docking studies, MgO and Fe2O3 NPs had the highest efficiency among the investigated MONPs.

Designing metal chelates of halogenated sulfonamide Schiff bases as potent nonplatinum anticancer drugs using spectroscopic, molecular docking and biological studies

In this contribution, five Ni(II) complexes have been synthesized from sulfonamide-based Schiff bases (SB¹-SB⁵) that comprise bromo or iodo substituents in the salicylidene moiety. The chemical structures of these compounds were extensively elucidated by different analytical and physicochemical studies. All ligands act as bidentate chelators with ON binding mode yielding octahedral, square planar, or tetrahedral geometries. The phenolic OH at δ 12.80 ppm in the free Schiff base SB² vanishes in the ¹H NMRspectrum of diamagnetic complex [Ni(SB²-H)₂] favoring the OH deprotonation prior to the chelation with Ni(II) ion. The appearance of twin molecular ion peaks ([M - 1]⁺ and [M + 1]⁺) is due to the presence of bromine isotopes (⁷⁹Br and ⁸¹Br) in the mass spectra of most cases. Also, the thermal decomposition stages of all complexes confirmed their high thermal stability and ended with the formation of NiO residue of mass 6.42% to 14.18%. Besides, antimicrobial activity and cytotoxicity of the ligands and some selected complexes were evaluated. Among the ligands, SB⁴ showed superior antimicrobial efficacy with MIC values of 0.46, 7.54, and 0.95 µM against B. subtilis, E. coli, and A. fumigatus strains, respectively. The consortium of different substituents as two bromine atoms either at positions 3 and/or 5 on the phenyl ring and a thiazole ring is one of the reasons behind the recorded optimal activity. Moreover, there is a good correlation between the cytotoxicity screening (IC₅₀) and molecular docking simulation outcomes that predicted a strong binding of SB² (16.0 μM), SB⁴ (18.8 μM), and SB⁵ (6.32 μM) to the breast cancer protein (3s7s). Additionally, [Ni(SB⁴-H)₂] (4.33 µM) has nearly fourfold potency in comparison with cisplatin (19.0 μM) against breast carcinoma cells (MCF-7) and is highly recommended as a promising, potent, as well as low-cost non-platinum antiproliferative agent after further drug authorization processes.