Extra-virgin olive oils (EVOOs) obtained from ′Brava′ and ′Mansa′, varieties recently identified from Galicia (northwestern Spain), were selected for in vitro screening to evaluate their capacity to inhibit key enzymes involved in Alzheimer′s disease (AD) (acetylcholinesterase (AChE), butyrylcholinesterase (BuChE) and 5-lipoxygenase (5-LOX)), major depressive disorder (MDD) and Parkinson′s disease (PD) (monoamine oxidases: hMAO-A and hMAO-B respectively). The gene discussed is BCHE; the disease is major depressive disorder.