Different varieties of maca root have been described according to the color of the hypocotyls (Tello et al 1992; Yllescas et al 1994). The most frequent studied have been red, black and yellow varieties (Gonzales et al 2005; Gonzales et al 2006a, Gasco et al 2007), the difference between them is their phitochemical constitution and biological activity (Gonzales et al 2005; Gonzales et al 2006a, Gasco et al 2007).
Maca root is also a rich source of essential amino acids, vitamins B1, B2, B12, C, D3, E, complex carbohydrates, carotene and minerals including calcium, zinc, phosphorus, magnesium and iron.
Many studies about hypocotyl composition have demonstrated that contains macaenes, macamides and macaridines, novels polyunsaturated fatty acids. Maca also contains sterols, such as campesterol, stigmasterol and -sitosterol; and benzylisothiocyanates (glucosinolaes secondary metabolite) (Zhenget al 2000).
Lepidium meyenii (Maca root) belongs to Brassicaceae family, being one of 16 families that contain in their phycochemistry composition glucosinolates, those compounds posses biological activities like antifungal, antibacterial and insecticides effects (Fahey et al 2001).
Glucosinolates are the most important secondary metabolites; the enzyme myrosinase present in the microflora of the human digestive tract converts these glucosinolates to a number of compounds including isothiocyanates (Fahey et al 2001).
It is suggested that maca properties over fertility could be associated to the presence of those isothiocyanates, glucosinolates hydrolysis products, specifically benzyl isothiocyanate and p-methoxibenzyl isotiocyanate (Fig.4) (Li et al 2001).
The dried hypocotyl of maca contents between 13 – 16% of proteins, and is rich in essential aminoacids (Li et al 2001).