Green ZnO nanoparticle synthesis using Tamarindus indica and application as a potent antibacterial and anticancer agent

This article provides an effectual, naturally amiable and jejune approach to synthesize green ZnO nanoparticles from zinc powder. The Tamarindus indica (tamarind) pulp extract was used as natural reductant in synthesis of ZnO NPs from zinc powder. UV–Visible spectroscopy and X-ray diffraction were utilized to measure absorption maxima and to calculate crystallite size respectively of synthesized NPs. XRD of green synthesized ZnO NPs heated at 500 °C, 600 °C and 700 °C revealed crystallite sizes of 4.89 nm, 23.3 nm, and 27.32 nm respectively. X-ray photoelectron spectroscopy (XPS) was applied to confirm the chemical composition. FE-SEM studies revealed that ZnO nanoparticles annealed at 700 °C displayed homogeneous nanoflakes morphology. Elemental composition for synthesized ZnO nanoparticles was confirmed using EDX. The synthesized nanoparticles were scrutinized for their antibacterial activity against Klebsiella pneumoniae MTCC 3384 strain using agar-well diffusion method with inhibition zone to be 20.5 ± 0.46 mm at a concentration of 15 mg/mL. SW480 cancer cell line was used to analyse the anticancer activity of synthesised ZnO NPs and the IC 50 value was found to be 62.559 µg/mL. ZnO nanoparticles possess good antibacterial and anti-cancer activity due to ROS mechanism. DPBF (1,3- diphenylisobenzofuran) assay confirmed that ZnO NPs generates singlet oxygen was the agent behind destroying cancer cells.