Solution combustion method for synthesis of ZnO NPs from Syzygium hemisphericum bark extract and a comparative analysis of the same with the crude bark extract for biomedical applications

This study is aimed at the bio-fabrication of zinc oxide nanoparticles (SHB@ZnO NPs) from the aqueous bark extract of Syzygium hemisphericum (SHBW) and their comparative analysis for biomedical applications. The FT-IR spectra reveal the Zn–O bond by the appearance of peaks at 411 cm⁻¹ and 398 cm⁻¹. Further, the peak at 370 nm in UV–Vis spectra analysis affirms the same. The X-ray diffraction reveals the ultrafine structure of NPs (10 nm). The morphology of the NPs depends on fuel load as analyzed from FESEM images. A prodigious antioxidant activity of SHBW was observed compared to ZnO NPs with IC₅₀ values of 8.877 ± 0.14 µg/mL and 236.74 ± 2.55 µg/mL, respectively. SHBW showed a markable α-amylase (37.68 ± 2.33 µg/mL) and α-glucosidase (37.68 ± 2.33 µg/mL) inhibitory activity compared to the SHB@ZnO-20. The antibacterial activity of synthesized NPs was observed against a wide range of strains. The HRBC membrane stabilization assay was carried out to substantiate the non-toxic nature toward human RBC’s (71.30% for SHBW and 46.96% for SHB@ZnO-20). The anticancer activity of ZnO NPs utilizing a definite volume of reducing agent was analyzed against A431 cancer cell lines which revealed that the cell viability decreased as NPs concentration (64.80% at 50 µg/mL) increased. Graphical abstract: (Figure presented.)