Lepidium meyenii Walp. improves sexual behaviour in male rats independently from its action on spontaneous locomotor activity

Lepidium meyenii Walpers (Maca) is traditionally employed in the Andean region for its supposed properties to improve energy and fertility. The aim of this study was to evaluate the effect of acute and chronic Maca pulverised root oral administration on rat sexual behaviour. Sixty male sexually experienced rats (20 group) were daily treated for 15 days with Maca 15 mg kg(-1), Maca 75 mg kg(-1) or saline 0.5 ml kg(-1). The following sexual performance parameters were evaluated at first and last day of treatment: 1st mount (ML), 1st intromission (IL), ejaculation (EL) and postejaculatory (PEL) latencies, intercopulatory interval (ICI) and copulatory efficacy (CE). An activity cage test was carried out to evaluate if Maca-induced locomotion changes could indirectly improve rat sexual performances. It was observed that both lower and higher Maca doses acutely decreased ML, IL and ICI in a significant way (P < 0.05), while only the 75 mg kg(-1) dose decreased the PEL (T = 29, P < 0.05). This effect seems to be the only one dose-dependent. After 15 days of treatment, both doses are able to significantly decrease ML, IL, EL and PEL, while the 75 mg kg(-1) dose decreased the ICI (T = 40, P < 0.05) too. IL, EL and PEL variations seem to be dose-related after chronic treatment. Moreover, chronic Maca treatment induced an apparently not dose-related increase in rat locomotion, during the second 10-min period of observation in the activity cage. The late in Maca-induced locomotion modification excludes that improvement of tested sexual performance parameters is related to an increase in rat aspecific activity. Thus, it was concluded that both acute and chronic Maca oral administration significantly improve sexual performance parameters in male rats. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.