Alzheimer's disease (AD) has a significant financial impact on society since it is believed to be the most common neurological condition and one of the main causes of death for the elderly. Curcumin's remarkable pharmacological effects were hampered by its low bioavailability. Applying curcumin in its nanoform, which would enable it to traverse the blood-brain barrier, might help get over these restrictions. This current study aimed to investigate the neuroprotective effects of nanocurcumin on the AD induced by aluminum chloride "AlCl3". 24 Swiss albino rats were divided into four groups; (I) negative control , group (II) diseased, group (III) protective, group (IV) therapeutic. At the end of experiment, behavioral test, assessment of biochemical markers, gene expression of neurogranin (RC3) and β-amyloid protein (APP), expression of phosphorylated Tau (p-Tau) and Glial fibrillary acidic protein (GFAP) imunohistochemically, and histopathological changes in the studied groups. Curcumin nanoform particles decreased the he number of errors and the latency to escape box in the preventive and therapeutic rats. Furthermore, they reduced the oxidative stress induced by AlCl3 in brain tissue, down-regulated the relative expression of RC3 and APP in hippocampus and improve the histopathological alterations in brain tissue. Curcumin coated with chitosan nanoparticles boosted drug permeability across the blood-brain barrier, boosted microglia activation, and accelerated the phagocytosis of the Aβ peptide, suggests that curcumin was among the most intriguing and promising compounds for developing therapies for AD. Additionally, neurogranin (Ng) as a post-synaptic membrane protein can be a promising tool for early diagnosis of cognitive decline.