https://rbej.biomedc.../1477-7827-3-16 Maca contains sterols, such as campesterols (27.3%), ergosterol (13.6%), brassicasterol (9.1%) Δ7,22-ergostadienol (4.5%) and sitosterol (45.5 %) [23], the latter having phytoestrogen activity. It has been suggested that β-sitosterol could cross the placenta [24]. In humans, it has been demonstrated that sitosterol can be excreted in milk and therefore, enter the neonate [25]. Maca chemical composition includes sitosterol, this compound would exert its effect on pups.
Treatment with Maca also increases male sexual behavior [12, 13, 14] and sperm production in mice and rats [7]. It is probable that main effects of Maca increasing uterine weight and litter size were not due to an estrogenic effect but to a progestin-like one, since Maca chemical composition include other sterols besides phytoestrogen sitosterol. Progesterone would certainly affect both, uterine weight via progesterone receptors, as well as prevent abortion. In mice and rats, progesterone is much more important in maintaining pregnancy than estrogen [16, 17]. Moreover, physiological level of progesterone acts in conjunction with androgens to facilitate copulatory behavior in male rats and mice [26, 27]. In addition, one of the most potent phytoestrogenic substance -6-(1,1-dimethylallyl) naringenin (6-DMAN)- did not have any effect on uterine wet weight in ovariectomized rats [28]. Our study demonstrates that Maca increases uterine weight. It is suggested that this activity may be produced by a progestin-like effect. However, more studies need to be performed to clarify this proposed mechanism.