The purpose of the study was to evaluate the potential effects of Citrus reticulate (mandarin) peel methanolic
extract (MPME) on memory dysfunction in rats. Memory impairment was produced by scopolamine (1.4 mg/kg,
intraperitoneally injected). Brain acetylcholinesterase enzyme (AChE) activity was measured to assess the central
cholinergic activity. This study also investigated the effect of scopolamine on norepinephrine, dopamine and serotonin
content in rat hippocampus, striatum and cerebral cortex. In addition, the levels of brain lipid peroxidation (LPO), nitric
oxide (NO) and glutathione (GSH) were estimated to assess the degree of oxidative stress. Scopolamine administration
induced a significant impairment of central cholinergic activity in rats, as indicated by a marked increase in AChE
activity. The impairment of the cholinergic system was associated with a significant alternation in brain monoamines.
Scopolamine administration also caused oxidant damage (elevation in LPO and NO and reduction in GSH levels). Pretreatment
of MPME (250 mg/kg, orally administered) significantly reduced scopolamine-induced alternation in brain
monoamines with an attenuation of scopolamine-induced rise in brain AChE activity and brain oxidative stress. It is
concluded that administration of mandarin peel extract, demonstrating antioxidant activity, may be of value for dementia
exhibiting elevated brain oxidative status.