The present study centered around the prospect of bio fabricating nanoparticles using Moringa oleifera leaf and investigating their therapeutic potential with an assessment of the antioxidant status. Synthesis of stable ‘green’ nanoparticles of Moringa leaf extract is successfully reported with an extensive characterization. The average particle size and polydispersity index (PDI) of the nanoparticles obtained by Dynamic light scattering (DLS) analysis were 141.6 nm and a polydispersity index (PDI) of 0.32 respectively. The UV–visible spectroscopy (UV–vis) revealed a strong red absorbance peak at 664 nm,characteristic of chlorophyll. Electron micrographs confirmed that particles were in the nano range and were spherical with minimal agglomeration. The constituent functional groups were assessed by Fourier transformed infrared spectroscopy (FTIR). The X-ray diffractograms of reflected both the amorphous and crystalline domains.Furthermore, the phytochemical screening showed a higher phenolic/ flavonoid content of the Moringa nanoparticles (NMo) in comparison to the bulk Moringa leaf extract(Mo). These results corresponded to a potent antioxidant status of the NMo which was assessed by three complementary antioxidant assays. The therapeutic potential of the nanoparticles was evaluated based on in vitro anti-diabetic assays and cytotoxicity assay on human cancer cell lines (MCF-7 and HepG-2). The key findings suggest a more profound therapeutic efficacy of NMo than the Moringa leaf extract.