Effects of Cyanidin Derivatives for the Aggregation of Cu/Zn Superoxide Dismutase 1

Cu/Zn superoxide dismutase 1 (SOD1), whose aggregation is considered cytotoxic, is implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS). Therefore, inhibiting SOD1 aggregation may represent a promising strategy for the treatment and prevention of this disease. We first screened seven polyphenols using an optimized thioflavin T (Th-T) assay and found that cyanidin exhibited the strongest inhibitory activity among the seven polyphenols. We then compared cyanidin with its derivativesdelphinidin, petunidin, malvidin, and cyanidin-3-glucoside (C3G). In this study, we concluded that delphinidin had the strongest antifibrillation activity among the five cyanidin derivatives. Turbidity, transmission electron microscopy (TEM), atomic force microscopy (AFM), dynamic light scattering (DLS), circular dichroism (CD) spectroscopy, and Fourier transform infrared (FT-IR) spectroscopy indicated that the inhibitory activity was influenced by the number of phenolic hydroxyl groups on the B-ring of the cyanidin derivatives. Based on the LDH assay, delphinidin was the most effective compound in preventing the formation of cytotoxic SOD1 aggregates in the cells. Furthermore, we found that the compounds also interfered with the SOD1 cross-linking. Finally, we transfected GFP-SOD1A4 V into Neuro2a cells and observed that the compounds' inhibitory activity on intracellular aggregation was limited.