ACHE and Alzheimer disease: In view of these considerations, the purpose of the present study has been to investigate the effect of limonene, one of the main constituents of several plants from the genus Citrus on acetylcholinesterase (AChE) activity and its putative neuroprotective effect against Aβ1-42 neurotoxicity in an in vitro model of AD, namely rat primary cortical neurons exposed to oligomeric species of the neurotoxic Aβ1-42 peptide.