Facile biosynthesis of CaO nanoparticles using extract of Tulbaghia violacea and evaluation of their antibacterial and cytotoxicity activity

Abstract

Inexpensive and environmentally friendly calcium oxide nanoparticles (CaO-NPs) were green synthesized using the aqueous extract of Tulbaghia violacea bulb. Their structural and optical properties were studied using X-ray diffractometer, transmission electron microscopy (TEM), scanning electron microscope (SEM), energy-dispersive X-ray (EDX), and UV–visible spectrophotometer. Also, their antibacterial activity against pathogenic strains (Gram-negative: Escherichia coli and Klebsiella oxytoca, and Gram-positive: Staphylococcus aureus and Bacillus cereus), as well as their anticancer activity in HeLa cells, were evaluated. Results showed that pseudo spherical nanoparticles of about 27.75 nm, with band gap energy of 3.6 eV were obtained. Also, at the highest tested concentration, the nanoparticles exhibited higher antibacterial potency on K. oxytoca with an inhibition zone of 13 mm, compared to other tested bacteria [E. coli (9 mm), S. aureus (9 mm), and B. cereus (11 mm)]. Further, the nanoparticles revealed remarkable anticancer activity in HeLa (IC50: 9.25 µg/mL) and HEK 293 (IC50: 21.1 µg/mL) cells compared to the standard drug (5-Fluorouracil; IC50: 17.5 µg/mL and 6.05 µg/mL, respectively). It was therefore concluded that the green synthesized T. violacea bulb extract-mediated CaO-NPs could potentially be used to inhibit the proliferation of pathogenic bacteria and cancer cells. However, further research to evaluate their pharmacological relevance and cytotoxic effects in normal mammalian cells is required.