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The effect of mechanical stirring on sol-gel synthesis of thorn-like ZnO nanoparticles (ZnO-NPs) and antimicrobial activities is successfully reported in this study. The in-house synthesized nanoparticles were characterized by XRD, SEM, TEM, FTIR, TGA, DSC and UV-visible spectroscopy. The X-Ray Diffraction analysis revealed the wurtzite crystal lattice for ZnO-NPs with no impurities present. The diametric measurements of the synthesized thorn-like ZnO-NPs (morphology assessed by SEM) were well accounted to be less than 50 nm with the help of TEM. Relative decrease in aspect ratio was observed on increasing the agitation speed. The UV-visible spectroscopy showed the absorption peaks of the ZnO-NPs existed in both UVA and UVB region. A hypsochromic shift in λmax was observed when stirring pace was increased from 500 rpm to 2000 rpm. The FTIR spectroscopy showed the absorption bands of the stretching modes of Zn-O between 500 cm−1 to 525 cm−1. The Thermal analysis studies revealed better stability for ZnO-NPs prepared at 2000 rpm (ZnO-2000 rpm). TGA revealed the weight loss between two main temperatures ranges viz. around (90 °C–120 °C) and (240 °C–280 °C). Finally, the effect of ZnO-NPs prepared at different stirring conditions on the growth of Gram-positive (Bacillus subtilis), Gram-negative (Escherichia coli) bacteria and a fungi (Candida albicans) were examined; which showed good antibacterial as well as antifungal properties. These findings introduce a simple, inexpensive process to synthesize ZnO-NPs using conventional methods without the use of sophisticated equipments and its application as a potent nano-antibiotic.

Aims:  To evaluate quorum sensing (QS) inhibitory activity of plant essential oils using strains of Chromobacterium violaceum (CV12472 and CVO26) and Pseudomonas aeruginosa (PAO1). Methods and Results:  Inhibition of QS‐controlled violacein production in C. violaceum was assayed using disc diffusion and agar well diffusion method. Of the 21 essential oils, four oils showed varying levels of anti‐QS activity. Syzygium aromaticum (Clove) oil showed promising anti‐QS activity on both wild and mutant strains with zones of pigment inhibition 19 and 17 mm, respectively, followed by activity in cinnamon, lavender and peppermint oils. The effect of clove oil on the extent of violacein production was estimated photometrically and found to be concentration dependent. At sub‐MICs of clove oil, 78·4% reduction in violacein production over control and up to 78% reduction in swarming motility in PAO1 over control were recorded. Gas chromatography–mass spectrometry analysis of clove oil indicated presence of many phytocompounds. Eugenol, the major constituent of clove oil could not exhibit anti‐QS activity. Conclusions:  Presence of anti‐QS activity in clove oil and other essential oils has indicated new anti‐infective activity. The identification of anti‐QS phytoconstituents is needed to assess the mechanism of action against both C. violaceum and Ps. aeruginosa. Significance and Impact of the study:  Essential oils having new antipathogenic drugs principle because of its anti‐QS activity might be important in reducing virulence and pathogenicity of drug‐resistant bacteria in vivo.

Copper-based compounds are promising entities for target-specific next-generation anticancer and NSAIDS therapeutics. In lieu of this, benzimidazole scaffold plays an important role, because of their wide variety of potential functionalizations and coordination modes. Herein, we report three copper complexes 1 – 3 with benzimidazole-derived scaffolds, a biocompatible molecule, and secondary ligands viz, 1–10-phenanthroline and 2,2′-bipyridyl. All the copper complexes have been designed, synthesized and adequately characterized using various spectroscopic techniques. In-vitro , human serum albumin (HSA) binding was also carried out using fluorescence technique and in-silico molecular modeling studies, which exhibited significant binding affinities of the complexes with HSA. Furthermore, copper complexes 1 – 3 were tested for biological studies, i.e., anticancer as well as NSAIDS. In vitro cytotoxicity results were carried out on cultured MCF-7 cell lines. To get the insight over the mechanism of action, GSH depletion and change in lipid peroxidation were tested and thus confirmed the role of ROS generation, responsible for the cytotoxicity of the complexes 1 – 3 . Moreover, the copper complexes 1 – 3 were tested for potential to act as NSAIDS on albino rats and mice in animal studies in-vivo . Additionally, we also predicted the mechanism of action of the copper complexes 1 – 3 using molecular modeling studies with COX-2 inhibitor.

Bacterial quorum sensing (QS) is a density dependent communication system that regulates the expression of certain genes including production of virulence factors in many pathogens. Bioactive plant extract/compounds inhibiting QS regulated gene expression may be a potential candidate as antipathogenic drug. In this study anti-QS activity of peppermint (Mentha piperita) oil was first tested using the Chromobacterium violaceum CVO26 biosensor. Further, the findings of the present investigation revealed that peppermint oil (PMO) at sub-Minimum Inhibitory Concentrations (sub-MICs) strongly interfered with acyl homoserine lactone (AHL) regulated virulence factors and biofilm formation in Pseudomonas aeruginosa and Aeromonas hydrophila. The result of molecular docking analysis attributed the QS inhibitory activity exhibited by PMO to menthol. Assessment of ability of menthol to interfere with QS systems of various Gram-negative pathogens comprising diverse AHL molecules revealed that it reduced the AHL dependent production of violacein, virulence factors, and biofilm formation indicating broad-spectrum anti-QS activity. Using two Escherichia coli biosensors, MG4/pKDT17 and pEAL08-2, we also confirmed that menthol inhibited both the las and pqs QS systems. Further, findings of the in vivo studies with menthol on nematode model Caenorhabditis elegans showed significantly enhanced survival of the nematode. Our data identified menthol as a novel broad spectrum QS inhibitor.