Zinc Oxide and Gold Nanoparticles Synthesized via Black Carrot Root Extract: A Dual-Action Strategy Against Bacterial Pathogens and A549 Lung Cancer Cells

Zinc oxide nanoparticles (ZnONPs) and gold nanoparticles (AuNPs) have gained a lot of attention in the pharmaceutical industry and have become a prominent metal oxide in biomedical applications, particularly in the area of anticancer and antibacterial therapy. In the present study, the green synthesis of novel nanomaterial by using root extract of black carrot (DC) (Daucus carota ssp. Sativus var. Atrorubens Alef.), ZnONPs, and AuNPs has been reported. The characterisation of DC-ZnONPs and DC-AuNPs is carried out through the physicochemical analysis following the estimation of its antibacterial and anticancer activity. The physicochemical data supports the successful characterisation of both the nanomaterial separately. Further, the study evaluated the antibacterial effect against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis through well diffusion method and susceptibility assay through minimum inhibitory concentration (MIC) determination. And the anticancer effect has been determined through the detection of nuclear condensation and measurement of intracellular ROS with or without the presence of nanoparticles in lung cancer cell line. DC-ZnONPs induced 50% inhibitory concentration (IC50) in A549 cells at 12.40 μg/mL which is much lower than the other two groups along with the standard. Similarly, DC-AuNPs induced 50% inhibitory concentration (IC50) in A549 cells at 11.62 μg/mL while the DC root extract was 33.77 μg/mL. The effective MIC50 in bacterial culture were observed at 6.15, 6.4, 7.31, and 5.2 μg/mL of DC-ZnONPs and 9.3, 5.4, 5.95 and 7.57 μg/mL of DC-AuNPs. This study concluded that the synthesis of DC-ZnONPs and DC-AuNPs is easily prepared with low cost, non-toxic, and eco-friendly method. Its cytotoxic action on A549 cells and their antibacterial characteristics on pave the way to be an alternative therapy for lung cancer and bacterial infection.