Epigallocatechin-3-Gallate-Synthesized Gold Nanoparticles Modulate Reactive Oxygen Species and Antioxidant Parameters in Brain and Heart Tissues Using a Chicken Embryo Model

Chemically synthesized gold nanoparticles (AuNPs) come with drawbacks, such as biological toxicity and ecological imbalances. Nonetheless, a knowledge gap remains regarding their impact on oxidative and antioxidant parameters. Here, environmentally friendly AuNPs were synthesized using epigallocatechin-3-gallate (AuNPs-EGCG). The successful synthesis of AuNPs-EGCG were confirmed using ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, atomic force microscopy, and dynamic light scattering. Antioxidant activity was assessed using free radical 2,2-diphenyl-1-picrylhydrazyl, oxygen radical absorbance capacity, and ferric reducing antioxidant power assays, while cytotoxicity properties were evaluated in the NIH3T3 fibroblast cells. Furthermore, the impact of AuNPs-EGCG on oxidative stress was investigated in the hearts and brains of chicken embryos. AuNPs-EGCG exhibited no cytotoxicity and was not toxic for chicken embryos at higher concentrations. However, exposure to lower concentrations (100 and 30 μg/mL) caused an increase in reactive oxygen species (ROS) levels and a decrease in total antioxidant capacity in the heart and brain, resulting in a disturbance in the redox balance attributed to a reduction in catalase activity and glutathione (GSH) content, and an increase in glutathione peroxidase activity. In contrast, AuNPs-EGCG at 300 μg/mL promoted an increase in GSH levels and modulation of ROS, while also reducing vascular density in the chorioallantoic membrane. Furthermore, AuNPs-EGCG did not cause lipid or protein oxidation. The present study offers evidence that supports the investigation of how AuNPs-EGCG can modulate antioxidant defense mechanisms and assess the safety of phytoantioxidant-functionalized nanoparticles in vivo. This may lead to new and innovative strategies for the utilization of nanomaterials in biological systems.