CuNPs were found to stimulate oxidative stress in tumor tissue homogenates as detected by MDA elevation and reduce antioxidant state as represented by a reduction in GSH and CAT activity compared to untreated tumor tissue, which eventually results in tumor cell death as detected in histopathological analysis that showed degenerative changes in the form of vacuolation of neoplastic cells in the tumor tissue of CuNPs/EC treated mice. Here, CAT is linked to neoplasm.