Effects of quercetin and derivatives on NAMPT/Sirtuin-1 metabolic pathway in neuronal cells: an approach to mitigate chemotherapy-induced cognitive impairment.

 The cognitive alterations observed in individuals undergoing cancer treatments have garnered more attention recently. Chemotherapy can reduce nicotinamide adenine dinucleotide (NAD+) levels by inhibiting nicotinamide phosphoribosyl transferase (NAMPT). This reduction can make cancer cells more susceptible to oxidative damage and death and may also affect non-cancerous cells, particularly the brain cells. During chemotherapy-induced suppression, the downregulation of the NAMPT-mediated NAD+/Sirtuin 1 (SIRT1) pathway may cause dyscognition. Objective: This study aimed to assess the role of quercetin and analogues in chemobrain and the associated mechanisms. Methods: The potential of quercetin and its derivatives interaction with NAMPT and SIRT1 proteins was performed using computational studies followed by their in vitro evaluation in SH-SY5Y cells. Molecular docking and simulation studies of human SIRT1 and NAMPT proteins with quercetin and its derivatives were performed. Differentiated SH-SY5Y cell lines were treated with quercetin and selected derivatives against Methotrexate and 5-Fluorouracil (MF) toxicity, by subjecting to cytotoxicity assay, flow cytometry, and RT-PCR analysis. Results: Quercetin, Rutin, and Isoquercetin showed interactions necessary in the activation process of both proteins. Cytotoxicity and flow cytometric studies demonstrated that the phytochemicals shield the differentiated SH-SY5Y cells from MF toxicity. As determined by RT-PCR investigations, NAMPT and SIRT1 gene mRNA expression was higher in test drug-treated cells at quercetin (0.12, 0.6 µM), rutin, and isoquercetin (16, 80 µM) and lower in MF-treated cells. Conclusion: The treatment of phytochemicals alleviated CICI by targeting NAMPT and SIRT1 proteins, which could lead to the identification of effective treatment strategies for the chemobrain.