Iron is significant, earth abundant and inexpensive materials in everyday use. Non toxicity and clean manufacturing process is still a challenging role in scientific world. The chain like Fe3O4 nanostructures were synthesized using the mixtures such as iron nitrate and Rambutan. Magnetite Fe3O4 was verified using X-ray powder diffraction (XRD). Metal oxide (Fe-O) and A(1g) and E-g phonon modes are substantiated employing Fourier transform infrared spectroscopy (FTIR) and Raman spectra. A product chemical state was investigated by high resolution X-ray photoelectron spectroscopy (XPS) spectra. Chain like morphology and polycrystalline nature is attributed by transmission electron microscopy (TEM) analysis. Weight loss activity was revealed through thermogravimetric analysis (TGA) analysis. In application studies, higher concentration of Fe3O4 nanostructures was more effective than the low concentration. Moreover, cytotoxicity effects and cell viability on human cancer cell lines were observed and tested for cancer treatment.