Assessing valproate-induced changes in NADH levels in patients with type 2 diabetes using a silver nanoparticle-based...

Type 2 diabetes is a common metabolic disease that is associated with increased oxidative stress and impaired nicotinamide-adenine dinucleotide (NAD⁺/NADH) ratio. NADH, as a key metabolic biomarker, plays a crucial role in assessing oxidative status. Herein, a spectrophotometric method based on in-situ synthesis of silver nanoparticles (Ag NPs) was validated for the quantification of NADH. In this method, NADH, acting as a reductant, reduced Ag⁺ to Ag⁰, resulting in Ag NPs formation that exhibited a specific optical absorption at 425 nm. The plasma from patients with type 2 diabetes was collected and analyzed by the aforementioned method for NADH level. Then, each plasma sample was treated in-vitro with an appropriate concentration of sodium valproate in the therapeutic range, and finally, their NADH concentrations were measured by the developed method. The method detected NADH in plasma with LOD of 0.05 µmol/L^-1 and good linearity (R² = 0.9965) within a range of 0.22-3.8 µmol/L^-1. The assay demonstrated acceptable precision, with intra-day and inter-day repeatability of 4.6% and 7.4% RSD, respectively. The results of in-vitro studies indicated that the level of NADH decreased following sodium valproate addition. It is noteworthy that this decrease was proportional to the increasing concentration of sodium valproate, suggesting the influence of this antiepileptic drug on the oxidative status in the plasma of patients with type 2 diabetes.