Biosynthesis, characterization and antimicrobial activities of zinc oxide nanoparticles from leaf extract of Mentha pulegium (L.).

The synthesis of metal and semiconductor nanoparticles is an expanding research area due to the potential applications in the development of novel technologies. In the present study, a simple and eco-friendly synthesis of zinc oxide nanoparticles (ZnO NPs) using leaf extract of Mentha pulegium L. has been used. The biosynthesized ZnO NPs were characterized various techniques such as UV-Vis absorption spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX) and Fourier transform infrared spectroscopy (FT-IR). The XRD data showed the crystalline nature of the nanoparticles and EDX measurements indicated the high zinc content of 56.26% and also oxygen with 43.74%. FT-IR confirmed the presence of functional groups of both leaf extract and ZnO NPs. The particles size and morphology determined from FE-SEM and TEM and UV visible absorbance spectrum of ZnO NPs exhibited the absorbance band at 370 nm. The synthesized ZnO nanoparticles as potential antibacterial agent has been studied on Escherichia coli and Staphylococcus aureus. These results indicate that aqueous extract of Mentha pulegium (L.) are effective reducing agents for green synthesis of ZnO NPs with significant antimicrobial potential.

Rad SS ，Sani AM ，Mohseni S 《-》

Eco-friendly preparation of zinc oxide nanoparticles using Tabernaemontana divaricata and its photocatalytic and antimicrobial activity.

The present work reports the green synthesis of Zinc Oxide Nanoparticles (ZnO NPs) using aqueous Tabernaemontana divaricata green leaf extract. ZnO NPs have been characterized by X-ray diffraction (XRD), Ultra Violet-Visible (UV-Vis) studies, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Fourier Transform-Infra Red (FT-IR) analysis. XRD pattern analysis confirms the presence of pure hexagonal wurtzite crystalline structure of ZnO. The TEM images reveal the formation of spherical shape ZnO NPs with the sizes ranging from 20 to 50 nm. The FT-IR analysis suggests that the obtained ZnO NPs have been stabilized through the interactions of steroids, terpenoids, flavonoids, phenyl propanoids, phenolic acids and enzymes present in the leaf extract. Mechanism for the formation of ZnO NPs using Tabernaemontana divaricata as bioactive compound is proposed. As prepared ZnO NPs reveals antibacterial activity against three bacterial strains, Salmonella paratyphi, Escherichia coli and Staphylococcus aureus. The ZnO NPs shows higher antibacterial activity against S. aureus and E. coli and lesser antibacterial activity against S. paratyphi compared to the standard pharmaceutical formulation. Photocatalytic activity of synthesized ZnO NPs was analyzed for methylene blue (MB) dye degradation with sunlight. Almost complete degradation of dye occurred in 90 min. This nano-ZnO, prepared by eco-friendly method will be much useful for dye removal and bacterial decontamination.

Raja A ，Ashokkumar S ，Pavithra Marthandam R ，Jayachandiran J ，Khatiwada CP ，Kaviyarasu K ，Ganapathi Raman R ，Swaminathan M ... -  《-》

Mycogenic Synthesis of Extracellular Zinc Oxide Nanoparticles from Xylaria acuta and Its Nanoantibiotic Potential.

The study aimed to find an effective method for fungal-mediated synthesis of zinc oxide nanoparticles using endophytic fungal extracts and to evaluate the efficiency of synthesized ZnO NPs as antimicrobial and anticancerous agents. Zinc oxide nanoparticles (ZnO NPs) were produced from zinc nitrate hexahydrate with fungal filtrate by the combustion method. The spectroscopy and microscopy techniques, such as ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX), dynamic light scattering (DLS), and transmission electron microscopy (TEM) with selected area electron diffraction (SAED), were used to characterize the obtained product. Antibacterial activity on Gram-positive (Staphylococcus aureus and Bacillus cereus) and Gram-negative (Pseudomonas aeruginosa and Escherichia coli) samples was tested by broth microplate dilution technique. ZnO NPs antifungal activity was determined against plant pathogenic and regular contaminating fungi using the food-poison method. The anticancerous assay of the synthesized ZnO NPs was also investigated by cell uptake, MTT assay, and apoptosis assay. The fungal synthesized ZnO NPs were pure, mainly hexagonal in shape and size range of 34-55 nm. The biosynthesized ZnO NPs could proficiently inhibit both Gram-positive and Gram-negative bacteria. ZnO NPs synthesized from fungal extract exhibited antifungal activity in a dose-dependent manner with a high percentage of mycelial inhibition. The cell uptake analysis of ZnO NPs suggests that a significant amount of ZnO NPs (1 μg/mL) was internalized without disturbing cancer cells' morphology. As a result, the synthesized ZnO NPs showed significant anticancer activity against cancer cells at 1 μg/mL concentration. This fungus-mediated synthesis of ZnO NPs is a simple, eco-friendly, and non-toxic method. Our results show that the synthesized ZnO NPs are an excellent novel antimicrobial and anticancer agent. Further studies are required to understand the mechanism of the antimicrobial, anticancerous action of ZnO NPs and their possible genotoxicity.

Sumanth B ，Lakshmeesha TR ，Ansari MA ，Alzohairy MA ，Udayashankar AC ，Shobha B ，Niranjana SR ，Srinivas C ，Almatroudi A ... -  《International Journal of Nanomedicine》

Green synthesis of ZnO nanoparticles using Solanum nigrum leaf extract and their antibacterial activity.

In the present investigation, we have described the green biosynthesis of ZnO nanoparticles (NPs) by using Solanum nigrum as capping agent. The functionalization of ZnO particles through S. nigrum leaf extract mediated bioreduction of ZnO was investigated through UV-Vis DRS, photoluminescence (PL), X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, Field Emission Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscopy (TEM), thermal gravimetric-differential thermal analysis (TG-DTA), X-ray photoelectron spectroscopy (XPS) and antibacterial activities. UV-Vis-DRS studies revealed that the indirect band gap 3.38 eV and photoluminescence study reveals the blue emission at 402, 447, 469 and 483 nm and the green emission at 529 nm respectively. In addition, the synthesized NPs are wurtzite hexagonal structure with an average grain size lies between 20 and 30 nm were found from XRD analysis. Further, FT-IR spectra revealed the functional groups and the presence of protein as the stabilizing agent for surrounding the ZnO NPs. The diameter of the NPs in the range of 20-30 nm was found from FE-SEM study. TEM analysis was investigated the ZnO NPs as a quasi-spherical in shape and their diameter at around 29.79 nm. Finally, the current study has clearly demonstrated that the particle size variations and surface area to volume ratios of ZnO NPs are responsible for significant higher antibacterial activities. Further, the present investigation suggests that ZnO NPs has the potential applications for various medical and industrial fields so, that the investigation is so useful and helpful to the scientific communities.

Ramesh M ，Anbuvannan M ，Viruthagiri G 《-》

RETRACTED: Facile, eco-friendly and template free photosynthesis of cauliflower like ZnO nanoparticles using leaf extract of Tamarindus indica (L.) and its biological evolution of antibacterial and antifungal activities.

In the present investigation, we chose the very simple and eco-friendly chemical method for synthesis of zinc oxide nanoparticles from leaf extract of Tamarindus indica (L.) (T. indica) and developed the new green route for synthesis of nanoparticles. Formed product has been studied by UV-vis absorption spectroscopy, Photoluminescence (PL) spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Field emission scanning electron microscopy (FE-SEM) and with corresponding energy dispersive X-ray analysis (EDX). Mainly, the present results depicted that the synthesized nanoproducts are moderately stable, hexagonal phase, roughly spherical with maximum particles in size range within 19-37 nm in diameter. The antibacterial and fungal activities of aqueous extracts of T. indica were ended with corresponding disk diffusion and Minimum Inhibitory Concentration (MIC). The highest mean zones of inhibition were observed in the ZnO NPs (200 μg/mL) against Staphylococcus aureus (13.1±0.28). Finally, it can be concluded that microbial activity of ZnO NPs has more susceptible S. aureus than the other micro organisms. Further, the present investigation suggests that ZnO NPs has the potential applications for various medical and industrial fields.

Elumalai K ，Velmurugan S ，Ravi S ，Kathiravan V ，Ashokkumar S ... -  《-》