Aqueous and hydroalcoholic extracts of Black Maca (Lepidium meyenii) improve scopolamine-induced memory impairment in mice

Lepidium meyenii Walp. (Brassicaceae), known as Maca, is a Peruvian hypocotyl growing exclusively between 4000 and 4500 m altitude in the central Peruvian Andes, particularly in Junin plateau. Previously, Black variety of Maca showed to be more beneficial than other varieties of Maca on learning and memory in ovariectomized mice on the water finding test. The present study aimed to test two different doses of aqueous (0.50 and 2.00 g/kg) and hydroalcoholic (0.25 and 1.00 g/kg) extracts of Black Maca administered for 35 days on memory impairment induced by scopolamine (1 mg/kg body weight i.p.) in male mice. Memory and learning were evaluated using the water Morris maze and the step-down avoidance test. Brain acetylcholinesterase (AChE) and monoamine oxidase (MAO) activities in brain were also determined. Both extracts of Black Maca significantly ameliorated the scopolamine-induced memory impairment as measured in both the water Morris maze and the step-down avoidance tests. Black Maca extracts inhibited AChE activity, whereas MAO activity was not affected. These results indicate that Black Maca improves scopolamine-induced memory deficits. (c) 2007 Elsevier Ltd. All rights reserved.