Lepidium meyenii

Lepidium meyenii, known asmacaorPeruvian ginseng, is an edibleherbaceousbiennial plantof the familyBrassicaceaethat is native to South America in the highAndesmountains ofPeruandBolivia. It was rediscovered for commercial purposes at the Meseta de Bombónplateauclose toLake Juninin the late 1980s.It is grown for its fleshyhypocotylthat is fused with ataproot, which is typically dried but may also be freshly cooked as aroot vegetable. As a cash crop, it is primarily exported as a powder that may be raw or processed further as agelatinized starchor as anextract. If dried, it may be processed into aflourfor baking or as adietary supplement.
ItsSpanishandQuechuanames includemaca-maca,maino,ayak chichira, andayak willku.
Antonio Vázquez de Espinosadescribed the plant following his visit to Perucirca1598, andBernabé Cobodescribed this plant in the early 17th century.Gerhard Walpersnamed the speciesLepidium meyeniiin 1843. In the 1990s, Gloria Chacon further distinguished a different species. She considered the widely cultivated natural maca of today to be a newer domesticated species,L. peruvianum.
However, mostbotanistsdoubt this distinction and continue to call the cultivated macaL. meyenii. TheLatin namerecognized by theUSDAsimilarly continues to beLepidium meyenii.It has been debated whether it is botanically correct to considermeyeniiandperuvianumto be distinct from one another.A 2015 multi-center study found differences in taxonomy, visual appearance, phytochemical profiles and DNA sequences when comparingL. meyeniiandL. peruvianum, suggesting that they are different and that their names should not be considered synonyms.
The growth habit, size, and proportions of maca are roughly similar to those ofradishesandturnips, to which it is related, but it also resembles aparsnip. The green, fragrant tops are short and lie along the ground.The thin, frilly leaves sprout in a rosette at the soil surface, not growing more than 12–20 cm (4.7–7.9 in) in height. The leaves show adimorphismaccording to the reproductive stage. They are more prominent in the vegetative phase and continuously renew from the center as the outer leaves die. The off-white,self-fertileflowers are borne on a centralraceme, and are followed by 4–5 mm (0.16–0.20 in) siliculate fruits, each containing two small 2.0–2.5 mm (0.079–0.098 in) reddish-gray ovoidseeds. Seeds are the maca's only means of reproduction. Maca reproduces mainly through self-pollination and is an autogamous species. The genome consists of 64 chromosomes. Maca is ashort-day plantfrom experiments with different day lengths.Some sources consider the maca an annual plant, as in favorable years, it can complete a lifecycle within a year.
Maca is the only member of the genusLepidiumwith a fleshyhypocotyl, which is fused with the taproot to form a rough inverted pear-shaped body. Traditionally, native growers have acknowledged four varieties of maca based on their root color: cream-yellow, half-purple, purple, and black; varying levels ofanthocyaninare primarily responsible for the color differences.Maca hypocotyls may be gold or cream, red, purple, blue, black, or green. Each is considered a "genetically unique variety," as the seeds of the parent plants grow to have roots of the same color. Specificphenotypes(in maca, 'phenotype' pertains mainly to root color) have been propagated exclusively to increase commercial interest.Cream-colored roots are the most widely grown and are favored in Peru for their enhanced sweetness and size. Black maca is both sweet and slightly bitter.
The natural environment of the maca is at 11–12ºS latitude and at an elevation of 3,800–4,400 m (12,500–14,400 ft) above sea level.At this elevation, temperatures of the growing season vary from −2 to 13 °C (28 to 55 °F) in monthly mean minimum or maximum, respectively. Temperatures can decline, however, as low as −10 °C (14 °F) andfrostsare common. Of the cultivated plants, maca is one of the most frost tolerant.Strong winds and sunlight are also characteristics of the native habitat of the maca.  Maca today is still mainly cultivated inPeru, in the highAndesof Bolivia, and to a small extent also inBrazil.Maca can be cultivated beyond its natural elevation range, over 4,400 m (14,400 ft) above sea level.
Maca (Peruvian ginseng) seedlings usually emerge about one month after sowing, with the onset of the rainy season in October. In the vegetative phase, from May to June, the lower part of the hypocotyl, as well as the upper part of the tap root, grows in size. After 260 to 280 days, it is formed into the harvestable hypocotyl. If the root is left in the soil, it is dormant for two to three months in the time of the cold, dry season until August. Then, it will form a generative shoot on which the seeds ripen five months later. One plant can form up to 1000 tiny seeds, 1600 of which weigh about one gram. Thus, only relatively few plants are needed for propagation. The cultivated plants are selected for preferred size and color, then placed 50–100 mm deep in pits with alternate layers of grass and soil to protect them from drying out. They are fertilized heavily, as maca is an exhaustive crop of soil.The cultivation cycle is strictly linked to seasonality.
Traditionally, land preparation was done by hand. Nowadays, tractor plowing is also used. As maca grows on sites where no other crops can be cultivated, it is often found after long fallows of sheep grazing pastures.Maca croplands, thus, traditionally are only fertilized with sheep and alpaca manure; however, fertilizer application could prevent soils from depleting in nutrients.
Weeding or pesticide application usually is not necessary.  The climate is not suitable for most weeds or pests. Nearly all maca cultivation in Peru is carried out organically; maca is seldom attacked. Maca is sometimes interplanted with potatoes, as it is known to maca farmers that the plant naturally repels most root crop pests.
The harvest is done manually, with the leaves left in the field aslivestock feedororganic fertilizer.
The yield for a cultivated hectare may reach an estimated 15 tons in fresh hypocotyls, resulting in around 5 tons of dried material.According to theMinistry of Agriculture of Peru, however, average maca yields for 2005 were only 7 t/ha, with a great variation between different sites.Although maca has been cultivated outside the Andes, it is unclear whether it develops the same active constituents or potency outside of its natural habitat. Hypocotyls grown from Peruvian seeds form with difficulty at low elevations, in greenhouses, or warm climates.
The average composition, on a dry matter basis, is 60–75%carbohydrates(primarily aspolysaccharides),10–14%protein, 8.5%dietary fiber, and 2.2%fats.
Maca containsglucotropaeolin,m-methoxyglucotropaeolin,benzylglucosinolates,polyphenols, (1R,3S)-1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (MTCA), andp-methoxybenzylisothiocyanate.Alkamidesare also present in maca.Maca contains several N-benzylamides referred to asmacamidesthat are structurally related toanandamide.
Nopharmacokineticdata have been published for maca.The presence of (1R,3S)-1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (MTCA) in the extracts of maca indicate a potential safety issue as amonoamine oxidase inhibitor(re. which seeβ-carboline) and possibility as amutagen.Due to these potential mutagenic properties of MTCA, the Agency for Sanitary Security in France warned consumers about the possible health risks of powdered maca root, a declaration disputed on the assumption that MTCA would be deactivated by boiling to process maca roots.MTCA-like compounds are associated withcravingbehaviour.
Due to its purported effect onfertility, maca grew in agricultural, commercial, and research interest from the 1990s to 2014.Market studies showed low acceptance of the particular maca taste by consumers when first exposed to it, creating a barrier for popularity of this food as a culinary vegetable. The economic interest existed more in the perceived but unproven health effects of the root's constituents supplied as an extract in a dietary supplement.
By 2014, agricultural and market interest in maca grew in China, but with challenges from Peruvian institutions who accused Chinese companies of illegally exporting maca and ofbiopiracy, as several Chinese patents had been filed to improve maca's propagation and genetic diversity.
Maca is mainly grown for the consumption of its roots. The majority of harvested maca is dried. In this form, the hypocotyls can be stored for several years.In Peru, maca is prepared and consumed in various ways, although traditionally, it is always cooked. The freshly harvested hypocotyl may be roasted in a pit (calledhuatia) and is considered a delicacy. Fresh roots usually are available only in the vicinity of the growers. The root can also be mashed and boiled to produce a sweet, thick liquid, then dried and mixed with milk to form a porridge,mazamorra.The cooked roots are also used with other vegetables inempanadas, jams, or soups. The root may be ground to produce flour for bread, cakes, or pancakes. If fermented, a weakbeercalledchichade macamay be produced. In 2010, a U.S.-based brewery called Andean Brewing Company became the first company to produce and commercialize beer made from maca under the brand KUKA Beer.From the black morphotype, a liquor is produced. Also, the leaves are edible or may serve as animal fodder. They can be prepared raw in salads or cooked much likeL. sativumandL. campestre, which are closely related genetically.
The prominent product for export is macaflour, a baking flour ground from the hard, dried roots. It is calledharina de maca. Maca flour (powder) is a relatively inexpensive bulk commodity, like wheat flour or potato flour. The supplement industry uses both dry roots and maca flour for different types of processing and concentrated extracts.  Another common form is maca, processed bygelatinization. This extrusion process separates and removes the tough fiber from the roots using gentle heat and pressure, as raw maca is difficult to digest due to its thick fibers.
Archaeological evidence exists for varying degrees of cultivation of maca in theLake Juninregion from around 1700 BC to 1200 AD.Maca has been harvested and used by humans in thepuna grasslandsof the Andean Mountains for centuries. Contrary to frequent claims that maca cultivation was common in what is today Peru, until the late 1980s, maca has been cultivated only in a limited area aroundLake Juninin central Peru. Historically, maca was often traded for lowland tropical food staples, such asmaize,rice,manioc(tapioca roots),quinoa, andpapaya. It also was used as a form of payment for Spanish imperial taxes.
Maca is said to have medicinal properties, but scientific research remains inconclusive.A 2016 systematic review found evidence suggesting that it improvessemenquality in healthy and infertile men.A 2011 systematic review found the evidence for the effectiveness of maca as a treatment formenopausal symptomsin women inconclusive.