Synthesis, structural elucidation, DFT calculation, biological studies and DNA interaction of some aryl hydrazone Cr3+, Fe3+, and Cu2+ chelates.

The current research focuses on the treatment of Cr(III), Fe(III) and Cu(II) metal ions with aryl hydrazone ligand named (E)-4-(((diphenylmethylene)hydrazono)methyl)benzene-1,3-diol (DPHB) to afford four novel solid complexes with high yields. Different characterization approaches, including infrared, UV-visible, and NMR spectroscopies, elemental analyses, and thermal gravimetric analysis (TGA), revealed that all mononuclear crystalline metal chelates with good thermal stability had a six-coordination with octahedral geometry. Density Functional Theory (DFT) computations were used and provided a reasonable explanation for these metal chelates' electrical and structural features. Furthermore, investigations of electronic absorption spectroscopy, hydrodynamics, and electrophoresis demonstrated that these new compounds interact with calf thymus deoxyribonucleic acid (CT-DNA) in a variety of ways. As a result, the Kb and ∆Gb≠ values of such interactions were in the following order: DPHBCu > DPHBCr > DPHBFe complex. Additionally, the novel metal chelates have been studied anti-bathogenically and found to be significantly effective compared to the comparable DPHB hydrazone ligand. The anti-proliferative activities of the investigated compounds were also evaluated against different lines of cancer cells and exhibited significant cytotoxic activity. In addition, observations of antioxidant activity suggest that antioxidant activity relative to ordinary ascorbic acid was demonstrated in the molecule.

Synthesis and Characterization of rGO@ZnO Nanocomposites for Esterification of Acetic Acid.

In the present work, the aim is to synthesize reduced graphene oxide (rGO) and zinc:reduced graphene oxide composite catalysts (ZnO:rGO) for esterification of acetic acid with n-heptanol. The physical and chemical characteristics of the rGO and rGO-metal oxide composite catalysts such as textural surface characteristics, surface morphology, thermal stability, functional groups, and elemental analysis were studied. The surface areas of rGO, ZnO(0.5 M), and ZnO(1 M) were recorded, respectively, at 31.72, 27.65, and 36.19 m2 g-1. Furthermore, esterification reaction parameters such as the reaction time, catalyst dosage, and reaction temperature for acetic acid were optimized to check the feasibility of rGO-metal oxide composites for a better conversion percentage of acetic acid. The optimized catalyst was selected for further optimization, and the optimum reaction parameters found were 0.1 wt % of catalyst, 160 min reaction duration, and 100 °C reaction temperature with a maximal yield of 100%. At 110 °C, the reaction conducted in the presence of 0.1 g of catalyst displayed more yield than the uncatalyzed reaction.

Uncaria rhynchophylla mediated Ag/NiO nanocomposites: A new insight for the evaluation of cytotoxicity, antibacterial and photocatalytic applications.

The increase of microbial resistance poses threats to human health. Therefore, efficient treatment of microbial resistance is a global challenge.. During this study, the Ag/NiO nanocomposite was fabricated via simple and ecofriendly method, using Uncaria rhynchophylla extract as a reducing and capping agent to avoid the aggregation of as synthesized nanomaterials. Here, a range of characterization techniques were employed to characterize the sample which includes UV-vis spectroscopy, X-ray diffraction, FTIR spectroscopy, electron diffraction spectroscopy (EDX), scanning electron microscopy (SEM). Furthermore, the resultant nanocomposite demonstrated an efficient ability for the inhibition of both gram-positive and gram negative pathogenic multidrug resistant bacteria. Additionally, the Ag/NiO nanocomposite showed a durable antioxidant effect against DPPH that could still reach 63% at very low concentration, i.e. 0.5 mg/mL. Interestingly, the synthesized nanocomposite is efficient for the production of reactive oxygen species (ROS) and shows no hemolytic activity. Likewise, the Ag/NiO nanocomposite displayed excellent photocatalytic activity to degrade 85% methylene blue (MB) by 4 mg/25 mL and could be used for waste water treatment. It is believed that synthesized nanostructure with desirable morphology and preparation simplicity can be promising material for antimicrobial, antioxidant and catalytic applications.

Facile synthesis of silver modified zinc oxide nanocomposite: An efficient visible light active nanomaterial for bacterial inhibition and dye degradation.

The present study reports the synthesis of silver (Ag) decorated zinc oxide (ZnO) nanocomposite via green synthesis method by using Acacia arabica plant leaves extract as both reducing and capping agent. The results clearly indicate a uniform distribution of Ag nanoparticles (NPs) over ZnO surface. Various analytical and spectroscopic techniques were used for investigating the formation and morphology of as-synthesized Ag/ZnO nanocomposites. Emergence of SPR at 424 and 378 nm confirmed the synthesis of AgNPs and ZnO respectively. The confirmation of elemental composition and crystal structure of prepared nanomaterials (NMs) was carried out via EDX and XRD analysis. Results obtained from HRTEM and SEM analysis indicated small sized spherically shaped NMs. The as-synthesized was checked for its photocatalytic activity towards degradation of MB in the presence as well as absence of light irradiation. Results of degradation study revealed that Ag/ZnO exhibits remarkable photocatalytic activity in the presence of light whereby removing 90% of MB within 80 min. Moreover, the antibacterial activity of synthesized nanocomposite was examined in both visible light and dark conditions. The experiment showed that nanomaterial depicts enhanced antibacterial activity in light in comparison to dark. The results showed that the inhibition diameter of Ag/ZnO nanocomposite in light was found to be 18 (±0.2), 22 (±0.3) against E. coli and S. aureus respectively. The inhibition zone of the said nanomaterial against E. coli and S. aureus in dark was 11 (±0.3), 14 (±0.5) respectively. These results conclude that activity is delivered both in the presence of visible light and dark but efficiency of antibacterial activity is found to be more in visible light in comparison.

Phytoassisted synthesis and characterization of palladium nanoparticles (PdNPs); with enhanced antibacterial, antioxidant and hemolytic activities.

With increasing demand for the treatment of microbial resistance around the globe, it is necessary to develop metallic nanoparticles , ideally by the use of nontoxic medium i.e. plant constituents, that could arrest the microbial growth. For this reason, small and highly crystalline PdNPs were effectively synthesized by using Eryngium caeruleum leaf extract as both the reducing and capping agent. During the synthesis of PdNPs, the size and shape were made controlled by using different solvents i.e., ethanol, methanol and aqueous extract of Eryngium caeruleum. A series of physicochemical characterizations were applied to inquire the synthesis, crystal structure, particles size, and surface morphology of PdNPs. Furthermore, the PdNPs demonstrated excellent potential for the inactivation of gram-positive and gram-negative bacteria, where the methanol-PdNPs exhibited maximum growth inhibition zones against tested bacteria as compared to ethanol-PdNPs and aqueous-PdNPs. Besides, PdNPs showed better antioxidant activity to effectively scavenge 2, 2 diphenyl-1-picrylhydrazyl (DPPH). More importantly, the synthesized PdNPs are not only active for ROS generation but also show no hemolytic activity. We believe that this greener approach uncovered the useful and efficient applications of highly active PdNPs and their biocompatibility.

Evaluation of the Anticancer Activity of Phytomolecules Conjugated Gold Nanoparticles Synthesized by Aqueous Extracts of Zingiber officinale (Ginger) and Nigella sativa L. Seeds (Black Cumin).

The conventional physical and chemical synthetic methods for the preparation of metal nanoparticles have disadvantages as they use expensive equipment and hazardous chemicals which limit their applications for biomedical purposes, and are not environment friendly. However, for the synthesis of biocompatible nanomaterials, plant-based techniques are eco-friendly and easy to handle. Herein a simple, single-step biosynthesis of gold nanoparticles using aqueous extracts of Nigella sativa (NSE) and Zingiber officinale (GE) as a reducing and capping agent has been demonstrated. The formation of gold nanoparticles (Au NPs) was confirmed by X-ray diffraction, UV-Vis, and EDS spectroscopies. Spectroscopic and chromatographic analysis of GE and NSE revealed the presence of bioactive phytochemical constituents, such as gingerol, thymoquinone, etc., which successfully conjugated the surface of resulting Au NPs. TEM analysis indicated the formation of smaller-sized, less-aggregated, spherical-shaped Au NPs both in the case of GE (~9 nm) and NSE (~11 nm). To study the effect of the concentration of the extracts on the quality of resulting NPs and their anticancer properties, three different samples of Au NPs were prepared from each extract by varying the concentration of extracts while keeping the amount of precursor constant. In both cases, high-quality, spherical-shaped NPs were obtained, only at a high concentration of the extract, whereas at lower concentrations, larger-sized, irregular-shaped NPs were formed. Furthermore, the as-prepared Au NPs were evaluated for the anticancer properties against two different cell lines including MDA-MB-231 (breast cancer) and HCT 116 (colorectal cancer) cell lines. GE-conjugated Au NPs obtained by using a high concentration of the extract demonstrated superior anticancer properties when compared to NSE-conjugated counterparts.

Photoinhibition and photocatalytic response of surfactant mediated Pt/ZnO nanocomposite.

Water pollution and bacterial resistance are universal problems. Drugs and protocols have been employed to deal with involved microbes and pollutants but these customary chemicals have many limitations. It is essential to produce new methods and materials to deal with these deleterious microbes. In the present contribution, highly efficient and stable nanocomposite of platinum activated zinc oxide was synthesized by a new plant extract and surfactant assisted protocol. The cetylpyridinium chloride was applied as surfactant to obtain high dispersion of spherical ZnO. The platinum ions were reduced on the ZnO surface by the use of Rhazya stricta plant extract. The prepared nanomaterial was used for photoinactivation of multidrug resistant bacterium Escherichia coli (E. coli). The synthesized nanomaterial showed strong E. coli inhibition efficiency in the presence of light and the observed diameter of zone of inhibition was 21 ±0.4. The effect of light on the inhibition of E.coli was studied by measuring the activated oxygen radicals inside the bacterium cell. The surface morphology of E.coli before and after treatment with Pt/ZnO was studied by SEM. Such effect was not observed in dark. The toxicity of the synthesized nanomaterials was also studied through haemolytic activity and the result shows that the nanomaterial prepared by the said method has very low toxicity. The photocatalytic degradation of methylene blue (MB) was also investigated in the presence of the synthesized nanomaterials. Effect of different parameters such as concentration of Pt/ZnO, Irradiation time and dye concentrations were also studied. An incredible photocatalytic deprivation of MB (98 %) was observed for Pt/ZnO nanocomposite as compared to individual Pt (48%) and ZnO (71%) nanoparticles after 5 minutes of irradiations. Further research is required to investigate the applications of Pt/ZnO nanocomposite.