Targeted drug delivery of oxazolidine derivative AP9 using chitosan nanoparticles for neuroprotection in a BPA-induced zebrafish model

This study evaluated neuroprotective potential of an oxazolidine derivative, (4-(4-methoxyphenyl)-3-(4-nitrophenyl)-1,2-oxazolidine) (named AP9), and its chitosan (Ch) nanoparticle formulation (AP9-Ch), utilizing an integrated in silico, in vitro, and in vivo zebrafish model. Network pharmacology and molecular docking identified AP9 as a lead chemical with high affinity for hub proteins: as AKT1, EGFR, ESR1, HIF1A, MTOR, and PARP1, implying an involvement in neurodegenerative disease pathways. In vitro tests showed that AP9 inhibited acetylcholinesterase by 85.85% at 100 μM, a level similar to that of galantamine. Nanoparticle analysis revealed a spherical morphology, reduced crystallinity, and effective conjugation, suggesting improved drug stability and release potential. Toxicity tests on zebrafish embryos revealed that AP9 was well tolerated up to 150 μM, with few developmental abnormalities. Behavioral assays showed that AP9-Ch reduced BPA-induced anxiety-like behavior, aggression, and cognitive impairment, as demonstrated by improved performance in open field, novel tank diving, mirror biting, and T-maze testing. Biochemical tests showed that antioxidant defenses were restored and lipid peroxidation was reduced, while histology revealed protection of brain cytoarchitecture. Gene expression investigations revealed downregulation of NF-κB, COX-2, and TNF-α, and overexpression of BDNF. Overall, these findings indicate that AP9-Ch is a promising multimodal neuroprotective drug with cholinesterase-inhibitory, antioxidant, and anti-inflammatory properties.