Effect of a lipidic extract from Lepidium meyenii on sexual behavior in mice and rats

Objectives. To determine the effect of oral administration of a purified li pidic extract from Lepidium meyenii (MacaPure M-01 and M-02) on the number of complete intromissions and mating in normal mice, and on the latent peri od of erection (LPE) in rats with erectile dysfunction. Methods. Mice and rats were randomly divided into several experimental and control groups. A 10% ethanol suspension of M-01 and M-02 was orally admini stered for 22 days to the experimental groups according to the dosage speci fied by the experimental design. On day 22, 30 minutes after the dose was a dministered to the male mice, 2 virgin female mice were placed with 1 male mouse. The number of complete intromissions of each male mouse in 3 hours w as recorded. In an assessment of 1 day of mating, each male mouse was cohab ited with 5 estrous female mice overnight. The number of sperm-positive fem ales was recorded. The LPE was measured to assess the sexual function in ra ts with erectile dysfunction. By using a YSD-4G multifunction instrument, a n electric pulse at 20 V was applied to stimulate the rat's penis, and the duration from the start of the stimulus to full erection was measured in se conds as the LPE. Results, In the normal male mice, the number of complete intromissions duri ng the 3-hour period was 16.33 +/- 1.78, 46.67 +/- 2.39, and 67.01 +/- 2.55 for the control group, M-01 group, and M-02 group, respectively. In the as sessment of mating, the number of sperm-positive females increased from 0.6 +/- 0.7 in the control group to 1.5 +/- 0.5 in the M-01 experimental group . The LPE of male rats with erectile dysfunction was 112 +/- 13 seconds wit h a regular diet (control group). The oral administration of M-01 at a dose of 180 or 1800 mg/kg body weight and M-02 at a dose of 45, 180, or 1800 mg /kg body weight reduced the LPE to 54 +/- 12 seconds, 54 +/- 13 seconds, 71 +/- 12 seconds, 73 +/- 12 seconds, and 41 +/- 13 seconds, respectively. Th e LPE of the surgical rats treated with M-01 at the lowest dose (45 mg/kg) was 121 +/- 12 seconds; thus, the change was not significant. Conclusions. Oral administration of M-01 and M-02 enhanced the sexual funct ion of the mice and rats, as evidenced by an increase in the number of comp lete intromissions and the number of sperm-positive females in normal mice, and a decrease in the LPE in male rats with erectile dysfunction. The pres ent study reveals for the first time an aphrodisiac activity of L. meyenii, an Andean Mountain herb. UROLOGY 55: 598-602, 2000. (C) 2000, Elsevier Sci ence Inc.