Developmental exposure to manganese or quercetin differentially programs adult oxidative stress, DNA fragmentation and behaviour in Drosophila

Developmental exposure to environmental neurotoxicants can program persistent vulnerability to oxidative and genomic injury. We compared the long-term effects of developmental manganese (Mn) and the dietary flavonoid quercetin in Drosophila melanogaster. Larvae were exposed to ordered doses of Mn or quercetin; adult outcomes (n = 4 vials/group unless stated) included survival, negative geotaxis (RING), hydrogen peroxide (H2O2), glutathione redox state (GSH/GSSG), malondialdehyde (MDA), antioxidant enzymes (SOD, CAT), acetylcholinesterase, dopamine, DNA fragmentation index (DFI) and advanced glycation end-products (AGEs). Conventional omnibus and pairwise post-hoc tests (ANOVA/Tukey or Kruskal–Wallis/Dunn) identified significant, dose-dependent increases in H2O2 and DFI with Mn exposure. Quercetin developmental exposure produced protective trends in redox markers and reduced genomic fragmentation signals. These findings implicate oxidative burden and DNA damage as measurable biomarkers of developmental Mn programming and identify candidate endpoints for targeted mechanistic and translational studies.