ZnO nanoparticles with spectroscopically controlled morphology, bioinspired from Holigarna grahamii (Wight) Kurz and delving its antioxidant and anticancer potential on A498 cell line

Zinc oxide nanoparticles (ZnO NPs) have emerged as a rising module operation in cancer detection, possessing multifunctional qualities and therefore being used for a variety of applications in the twenty-first century. The current research focuses on the optimization via the green approach for the synthesis of zinc oxide nanoparticles employing leaves of Holigarna grahamii (HG). The nanopowder was characterized by using various analytical techniques to explore their bonding, morphological and structural features. The UV–visible spectrum showed an absorption peak at 276.8 nm reflecting surface plasmon resonance (SPR) of ZnO NPs. FTIR spectra revealed the presence of various functional groups. PXRD (Powder X-ray diffraction) patterns confirmed the hexagonal phase of ZnO with the wurtzite structure. The scanning and transmission electron microscopic (SEM and TEM) analysis revealed the spherical structures. The size range of nanoparticles obtained upon synthesis at optimum conditions was 9–16 nm as reported by TEM. The zeta potential value of − 26.7 mV revealed the surface charge of green synthesized ZnO NPs. HG extract showed significantly greater DPPH scavenging action at lower concentrations (12.5–50 µg/ml) with IC 50 value of 141.8 µg/ml compared to HG-ZnO NPs (147.5 µg/ml) and ascorbic acid (68.85 µg/ml). However, HG-ZnO NPs showed higher scavenging activity then HG extract as the concentration was increased. Furthermore, FRAP assay and PM assay revealed that HG extract and HG-ZnO NPs are good radical scavengers. The cytotoxic effect of HG extract and ZnO NPs with various concentrations (6.25–200 μg/ml) was investigated against A498 cell line (Human renal carcinoma) along with non-cancerous HEK-293 cell line by MTT and XTT assay which showed dose dependent response. Selectivity index were found to be 5.45 (HG extract), 6.64 (HG-ZnO NPs) and 3.83 (cisplatin) in case of MTT assay and 7.35 (HG extract), 4.10 (HG-ZnO NPs) and 3.37 (cisplatin) in case of XTT assay. SI value more than 2 was considered as high selectivity. Cellular morphology studies after MTT and XTT assay exposure revealed that cancer cell viability decreased with increasing ZnO NP concentration. Annexiv V and DAPI staining revealed that HG extract and HG-ZnO NPs induced a significant apoptosis of the A498 cells in a dose-dependent manner. As a result, this work reports a simple and effective green technique for the production of ZnO NPs with anticancer potential.