In the present work, NiO nanoparticles based on Andrographis paniculata (leaf extract) were prepared through the microwave-assisted method. The obtained nanoparticles were analyzed using XRD, FTIR, SEM with EDS, HRTEM, UV-Vis and luminescence studies. XRD exhibits cubic structure with an average crystallite size of 24nm. The vibrational stretching mode of nickel oxygen bond is observed at 470cm(-1). The optical energy bandgap value of NiO nanoparticles is found to be 3.51eV. The luminescence emission peaks observed at 350, 439, 485, and 530nm. Further, the photodegradation (Evans blue) of prepared nanoparticles was assessed. Anti-breast cancer activity of the prepared nanoparticles was tested against the MCF-7 cell line.