Terminalia catappa Fallen Leaves Stabilized Zirconia Nanoparticles for Enhanced Anticancer and Antibacterial Activities

Zirconia nanoparticles (ZrO₂ NPs) are eco-friendly and biocompatible materials used for various biological applications. Herein, we reported Terminalia catappa (T. catappa) fallen leaves extract encapsulated ZrO₂ NPs without using a chemical reducing agent. The bandgap, absorption, functional groups, and crystalline structure were identified using a UV-Visible spectrophotometer (UV-Vis), a Fourier transform infrared spectrometer (FT-IR), and an X-ray diffractometer. The transmission electron microscope (TEM) images confirmed the formation of spherical particles with an average size of 6 nm. The absorption in the range of 299-307 nm confirmed the formation of ZrO₂ NPs. The stretching vibration bands at 467 and 621 cm⁻¹ confirmed the presence of the Zr-O-Zr bond in ZrO₂ NPs. According to the X-ray diffraction pattern (XRD), the average crystallite size of the ZrO₂ NPs was 4 nm with a cubic structure. The nanoparticles Zr0.01, Zr0.02, and Zr0.03 exhibited 26, 28, and 32 mm zones of inhibition against Lactobacillus acidophilus, Staphylococcus albus, and Streptococcus mutans at a maximum concentration of 25µg/ml. The ZrO₂ exhibited an IC₅₀ value of ZrO₂ to be 32.63 μg/mL against A549 cell lines. Therefore, biogenic T. catappa extract-encapsulated zirconia nanoparticles can be used for the development of potential antibacterial and anticancer agents.