Green synthesis, antioxidant and anticancer activities of TiO2 nanoparticles using aqueous extract of Tulbhagia violacea

Abstract

In this study, titanium oxide nanoparticles represented as TiO2(1), TiO2(2), and TiO2(3) were prepared using different volumes (10, 20, and 40 mL, respectively) of aqueous leaf extract of Tulbhagia violacea. The physicochemical characteristics of these materials were established using X-ray diffraction (XRD), ultraviolet–visible (UV–vis) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy. The obtained XRD pattern confirmed the formation of the anatase TiO2 phase in all the prepared materials irrespective of the volume of extracts used. Nevertheless, TiO2(2) nanoparticles obtained using 20 mL of plant extract showed the highest crystallinity. The maximum absorption wavelength found in the region between 260 and 267 nm in the UV–vis spectroscopy study suggested a quantum size effect. All synthesized TiO2 nanoparticles appeared to possess varying shapes and sizes, mostly dominated by rectangular shapes that were irregularly distributed across the materials. The material was found to be highly agglomerated due to the high calcination temperature. The antioxidant assay showed weak to moderate activity relative to the standard ascorbic acid. Also, compared to 5-Fluorouracil, all the nanoparticles exhibited moderate cytotoxicity against HEK 293 and HeLa cell lines. The TiO2 (1) showed the best specificity towards the cancer cell line with IC50 values of 29.73 and 34.27 µg/mL for both HeLa and HEK 293 cell lines, respectively. This suggests its potential as a promising candidate in applications where it is important to protect healthy cells.

Keywords

• Titanium oxide
• Green synthesis
• Tulbhagia violacea
• Cytotoxicity
• Antioxidant