The effects of different concentrations (0, 50,100, 1000 and 2500 mg/L) of engineered aluminum and nickel oxide nanoparticles (Al 2 o 3 and NiO NPs) on plant growth, oxidative stress and antioxidant activities in the hydroponically grown tissues of Nigella arvensis L. were investigated. The plant biomass was significantly increased under 50 and 100 mg/L of Al 2 o 3 NPs or 50 mg/L of NiO NPs treatment, but was significantly decreased at higher concentrations of these nanoparticles. Assays of several enzymatic antioxidants such as ascorbate peroxidase (APX), catalase (CAT), superoxide dismutase (SOD) and peroxidase (POD) in roots and shoots indicate a general increase of activities after exposure to 50-2,500 mg/L of Al 2 o 3 NPs and NiO NPs. The results are corroborated by an increased 2,2-diphenyl-1-picryl hydrazyl (DPPH) scavenging activity, total antioxidant capacity, total reducing power, total iridoids content, total saponin content, and total phenolic content in treated plants by Al 2 o 3 NPs compared to the control plants. By contrast, the antioxidant activities, formation of secondary metabolites, and other related physiological parameters such as the total antioxidant capacity, DPPH scavenging activity and total saponin content were inhibited after the concentration of NiO NPs was increased to 100 mg/L. Total phenols, saponins, iridoids and total antioxidant content and DPPH scavenging activity were increased in plants treated with 100-2,500 mg/L Al 2 o 3 NPs. Overall, these two nanoparticles displayed different effects in the shoots and roots of plants at different concentrations, which may be due to their physico-chemical properties. Rapid development of nanotechnology has greatly expanded the applications of engineered nanoparticles (ENPs) in commercial and industrial products 1. Increased application and potential accumulation of ENPs in the environment and their unknown interactions with different organisms, aggravated by some reports of greater toxicity at nanoscale than the bulk scale, caused broad concerns about the environmental health and safety of ENPs 2,3. Previous studies have demonstrated some disruptive effects of some ENPs on the natural environment including water, air, and soil quality 4. Plants are one of the most essential components of the ecosystem and interact with ENPs closely 5. These ENPs could be taken up by plants, and enter into the food chain through dietary consumption, ultimately affecting human health 6. Many previous investigations explored the potential applications of ENPs in agriculture 7-10. However, the majority of previous studies in ENPs-plant interactions focused on the potential toxicity of nanoparticles to higher plants. Both positive and negative or insignificant effects of ENPs on plants have been reported 11. In general, the phytotoxicity of ENPs is mediated through the production of reactive oxygen species (ROS) in plant cells 12. Even though ROS are normally produced within plants as a byproduct of metabolic processes in chloroplasts and other organelles 13,...

In the present study, different effective parameters (temperature, reaction time, and pH) on the synthesis of quercetin‐assisted silver nanoparticles (QE‐AgNPs) are optimized. These biogenic NPs are characterized by different physico‐chemical analyses, including transmission electron microscopy, X‐ray diffraction, Fourier transform infrared (FTIR) spectroscopy, and UV‐visible spectroscopy. In addition, the biological properties of QE‐AgNPs are evaluated through antioxidant, antimicrobial, anti‐inflammatory, hemolysis, and coagulation time assays. The formation of QE‐AgNPs is affected by different parameters. The optimum condition for the synthesis of QE‐AgNPs is attained at 70 °C and pH 7. Prepared QE‐AgNPs show a spherical shape with a crystalline nature and an average particle size of 20 ± 3.6 nm. The role of QE as a reducing and capping agent in the preparation process of QE‐AgNPs is demonstrated using FTIR analysis. These NPs with excellent antioxidant activity (82.3% at a concentration of 400 µg mL−1) and anti‐inflammatory properties (82.5% and 100% at concentrations of 37.25 and 500 µg mL−1, respectively), show good antimicrobial effects, particularly against Staphylococcus aureus. Furthermore, the results of the hemolytic and coagulation assay of QE‐AgNPs indicate their hemo‐compatibility. Therefore, hemo/bio‐compatible QE‐AgNPs with excellent and unique properties can be employed in different medicinal and pharmacological applications.

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The discovery and development of active compounds to eliminate drug resistance and side effects is a crucial process. In this study, the leaf infusion of Dracocephalum kotschyi Boiss as a novel green alternative is used to synthesize silver nanoparticles (Drac‐AgNPs). Antibacterial, cytotoxicity effects, hemocompatibility, and the catalytic properties of these nanoparticles are evaluated. The synthesis of Drac‐AgNPs is confirmed by UV–vis spectroscopy, X‐ray diffraction, Fourier‐transform infrared spectroscopy, and transmission electron microscopy, where Drac‐AgNPs are spherical, with a size range of 5–63 nm. Their IC50 values against H1299 and MCF‐7 cell lines are above 50 and 100 μg mL−1, respectively. Drac‐AgNPs are effective against an inclusive range of the gram‐positive and gram‐negative bacteria, that is, Staphylococcus epidermidis, Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Serratia marcescens, and Pseudomonas aeruginosa, and a low hemolytic effect makes them an exceptional AgNP with a great hemocompatibility. They show a moderate catalytic‐effect in terms of removing methylene blue, with 67% degradation. Altogether, Drac‐AgNP, as a multi‐tasker material, shows potential for the prevention and treatment of infections and photothermal/chemotherapy of cancers.