Nanoparticle and nanomaterial-based treatments have improved a lot recently in terms of bioavailability, effectiveness, and reduced toxic and side effects. Many studies found a protective effect of fullerene C60 derivatives as potent free radical scavengers in biological systems and also showed neuroprotective properties when tested on in vivo models of ischemic stroke. This study assessed the antioxidant effects of Nanosof® powder suspension, an oxygenated fullerene compound, on various cell types exposed to exogenous free oxygen radicals. Cor.4U® cardiomyocytes and bEnd.3, BV-2, HEK293/hERG1 cell lines were treated with Nanosof® powder suspension alone or during exposure to 100 µM H2O2 for 24 h, in order to check the nanoparticle capacity to neutralize reactive oxygen species, using MTS or MTT to assess viability. We found no significant change in the viability of cells treated with Nanosof® compared to control. In the presence of H2O2, Nanosof® increased cell viability compared to H2O2 exposure alone. Nanosof® treatment showed no side effect; moreover, it exerted a protective effect on all three tested cell lines and Cor.4U® cardiomyocytes, indicating that treatment with this oxygenated fullerene may benefit various conditions.