Phyto-assisted synthesis of ZnO nanoparticles using Ananas comosus peel extract: dual functionality in dye removal and cancer cell inhibition

Pineapple (Ananas comosus) and its peels are known to contain large amounts of antioxidant molecules. The work focuses on the phyto-assisted synthesis of zinc oxide (ZnO) nanoparticles (NPs) using an aqueous extract of pineapple peels (PP-ZnO NPs). The synthesized ZnO NPs were characterized using Ultraviolet-visible diffuse reflectance spectroscopy (UV-DRS) with absorption peaks at 218.5 nm and 352.5 nm, confirming the presence of ZnO NPs. The X-ray diffraction (XRD) analysis confirms the successful phyto-assisted synthesis of ZnO NPs using pineapple peel extract. The diffraction pattern aligns with the hexagonal wurtzite structure of ZnO. The Fourier transform infrared (FTIR) peaks obtained at 1577 and 1409 cm− 1 confirm the involvement of the pineapple peel’s phytochemicals in the synthesis of ZnO NPs. The topographical analysis using Scanning Electron Microscope (SEM) revealed that the PP-ZnO NPs were irregular in shape with an average size of 86 nm. The potential of PP-ZnO NPs to degrade methylene blue (MB), an organic dye, was analysed. MB dye was degraded within 30 min, as confirmed by the absence of absorption spectra after the incubation period. The reaction kinetics for the degradation of MB dye follow a pseudo-first-order reaction. The cytotoxic property of the PP-ZnO NPs was assessed using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The 50% inhibitory concentration (IC50) of PP-ZnO NPs was found to be 3.41 µg/mL against MDA-MB-231 cells. The PP-ZnO NPs were also found to inhibit the migration of MDA-MB-231 cells at a concentration of 3.41 µg/mL, as shown using the scratch assay.