Synthesis of biologically active tungsten nanoparticles stabilized by toluene soluble Vitex negundo extracts and evaluation of their antimicrobial, antioxidant and anticancer properties

•Stable and solid tungsten nanoparticles were prepared.•The size of the prepared tungsten nanoparticles was nearly 10 nm.•The solubility of tungsten nanoparticles is very high in most of the organic solvents.•They have good antimicrobial and antioxidant activity. Stable and solid powder tungsten nanoparticles (VNTE-WNPs) were prepared from toluene soluble Vitex negundo plants extracts (VNTE) by two step phase transfer method, which was confirmed by UV–Visible and FT-IR spectroscopic methods. The size and surface morphology of the VNTE-WNPs were analyzed by SEM, TEM, and XRD methods and the size of the nanoparticles range in between 3 and 15 nm. Antioxidant studies of VNTE-WNPs was compared to standard rutin and it shows that, the antioxidant activity of VNTE-WNPs was significantly increased than standard. Antioxidant studies shows that only 36, 27, 35 and17 µg/mL of VNTE-WNPs was needed to inhibit 50 percent concentration of antioxidants by SOD, NO, H2O2 and DPPH respectively. The antibacterial and antifungal studies of VNTE and VNTE-WNPs were evaluated by well diffusion methods and the results were compared with standard amphotericin for fungi and streptomycin for bacteria. Against all the bacterial strains VNTE shows less activity than VNTE-WNPs, but when it interacted with tungsten nanoparticles, its activity was increased. VNTE-WNPs show higher activity than streptomycin against other bacterial strains. Results of antifungal studies confirm that our isolated VNTE have good antifungal activity against selected fungal strains and also it was further increased maximum two times when it capped or stabilized with tungsten nanoparticles. Maximum zone of inhibition 22 and 29 mm was found against M. indicus for fungi and E. coli for bacteria. Anticancer activity of the plant extract and the nanoparticles was examined for human glioblastoma cell line T98G using MTT assay and the result shows VNTE-WNPs have good anticancer activity even at very lower concentrations. [Display omitted]