Beyond Amyloids: Neuroprotective Potential of Betanin and its Derivatives Against Alpha-Synuclein Aggregates and ROS...

The aggregation of alpha-synuclein (αSN) is a key pathological feature of Parkinson's disease (PD), leading to neural cell death via reactive oxygen species (ROS) overload and activation of downstream neurotoxic pathways. Betanin, a beetroot-derived small molecule, has exhibited antioxidant and neuroprotective properties. In this study, three betaxanthins-Bxn-A, Bxn-B, and Bxn-C-were chemically synthesized from betanin to enhance its therapeutic properties. Betaxanthin Bxn-A effectively reduced intracellular ROS levels without cytotoxicity, even at 500 µM. Additionally, betanin and its derivatives revealed neuroprotective effects, including significant reductions in apoptosis, preservation of mitochondrial membrane potential, modulated autophagy, and enhanced cell viability in PD-model cells. In terms of aggregation inhibition, betaxanthins Bxn-A and Bxn-B significantly reduced αSN aggregation compared to the control after 48 h of incubation. Betaxanthin Bxn-A also triggered disaggregation of existing aggregates and inhibited formation of large, insoluble species. Moreover, αSN aggregation and disaggregation products formed in the presence of betanin or its derivatives exhibited significantly lower cytotoxicity than those formed in their absence. Specifically, cells treated with aggregates formed in the presence of 50 µM betaxanthin Bxn-B showed 100% viability, while those treated with disaggregation products formed in the presence of 100 µM betaxanthin Bxn-A showed 20% greater viability than those treated with untreated disaggregates. Molecular docking revealed interactions between betaxanthins and key αSN residues, suggesting destabilization mechanisms. Docking analyses with five ROS-PPI network key proteins-C5, CDC42, BCL2, CDKN1A, and CDKN1B-indicated potential roles in inhibiting oxidative stress-related pathways. Drug-likeness predictions indicated that the derivatives enhanced pharmacological potential, making them promising candidates for PD treatment.