The protective activities of water-soluble C₆₀ derivatives against nitric oxide-induced cytotoxicity in rat pheochromocytoma cells

In this study, the protective activities of water-soluble C₆₀ derivatives against nitric oxide (NO) induced cytotoxicity were investigated. To overcome C₆₀ insolubility in water, we modified C₆₀ with β-alanine, valine or folacin. The compounds were characterized by FT-IR, ¹H NMR, ¹³C NMR, LC-MS, elemental analysis, light scattering and TEM. Investigation of the possible NO-scavenging activities of water-soluble C₆₀ derivatives demonstrated that they expressed direct scavenging activity toward NO liberated within solution of sodium nitroprusside (SNP). In parallel, following exposure of cells to SNP (1 mM), a marked decrease in mitochondrial membrane potential, cell viability, activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px), as well as increased levels of intracellular NO accumulation and malondialdehyde (MDA) production were observed. Moreover, SNP caused significant elevation in intracellular caspase-3 activity, and induced apoptotic death as determined by flow cytometric assay. However, pretreatment of the cells with water-soluble C₆₀ derivatives prior to SNP exposure blocked these NO-induced cellular events noticeably. Experiments demonstrated that the aggregation morphology could impact the NO-scavenging abilities and protective effects on apoptosis of water-soluble C₆₀ derivatives. The results suggest that water-soluble C₆₀ derivatives have the potential to prevent NO-mediated cell death without evident toxicity.