Curcumin-Conjugated Gold Nanoparticles Modulate Oxidative Stress and Antioxidant Activity and Maintain Intestinal Histoarchitecture in Drosophila melanogaster Larvae

Embryonic development is highly sensitive to oxidative stress, which can disrupt homeostasis. A strategy for mitigating oxidative stress induced by gold nanoparticles (AuNPs) involves the development of nanoparticles functionalized with phytoantioxidants through green chemistry methods, which also enhances the bioavailability of these antioxidants. In this study, environmentally friendly AuNPs were synthesized using curcumin (AuNPs-C), characterized by a spherical shape, uniform size, and a diameter of 7.2 ± 1.2 nm. The effects of AuNPs-C on oxidative stress in Drosophila melanogaster (Canton-S strain) during embryonic development were investigated, focusing on antioxidant defenses, oxidative damage, and morphological changes in the gastrointestinal tract. Exposure of Drosophila eggs to 50–200 μg/mL of AuNPs-C had no effect on hatching rates or pupal/adult development, with eclosion rates remaining above 50%. AuNPs-C did not elevate reactive oxygen species levels or induce lipid and protein oxidation in larvae exposed to 200 μg/mL. Oxidized protein products and malondialdehyde (MDA) levels remained comparable to those of the control group (70 ± 3 μM chloramine-T eq and 0.8 ± 0.1 nM MDA eq, respectively). Although AuNPs-C did not affect catalase activity or glutathione content, it reduced superoxide dismutase activity by 67% ± 6%. Additionally, AuNPs-C did not cause any damage to the gastrointestinal tract or alter the gut permeability of third-instar larvae. This study offers a deeper understanding of how AuNPs-C influence oxidative stress and antioxidant defense mechanisms in animal development and provides a basis for assessing the safety of phytoantioxidant-functionalized nanoparticles in vivo.