IV. Specialized Applications of Nutraceuticals

Science Behind Maca: A Traditional Crop from the Central Andes

ABTRACT

Lepidium meyenii, better known as maca, is a plant that grows 4000 m above sea level in the Central Andes. It has been used in Peruvian traditional medicine for centuries, with reports of its use to increase the offspring of domestic animals dating back from the 16th century. Traditional knowledge about its handling, preparation methods, and beneficial properties have survived until today, and guided the scientific community to conduct experimental trials to test the veracity behind these claims. The main health effects of maca as an energy booster and fertility enhancer herb has been confirmed in animal models and clinical trials. Other properties unknown to native Peruvians have also been discovered. This chapter aims to cover the tradition behind the medicinal usage of this nutritional plant and the scientific research that demonstrates its properties.

INTRODUCTION

It is estimated that there are as many as 1400 plant species currently used in traditional Peruvian medicine (Lock et al., 2016). Currently, the main interest in the national and international market is the plant known as maca (Lepidium meyenii) (Figure 10.1). In several reports, it is possible to find the description that Peru is the land of superfoods, being characterized by a variety of Peruvian agricultural products that promote a healthy life. Among these, Lepidium meyenii (maca) is included. (Gonzales, 2017).

Export of Peruvian nutraceuticals (Free on Board, FOB, price, 2000-2012 period. (Source

FIGURE 10.1 Export of Peruvian nutraceuticals (Free on Board, FOB, price, 2000-2012 period. (Source: Gonzales et al., 2017: IANAS)

Lepidium meyenii (maca) is a plant belonging to the Brassicaceae family cultivated exclusively between 4000 and 4500 m above the sea level (Gonzales, 2017). Maca is traditionally used because of its nutritional and allegedly medicinal properties and is now a famous food supplement, with growing international interest over the last two decades.

The main bioactive compounds are glucosinolates, macamides, macaenes, alkaloids, and a series of novel thiohydantoins. Interestingly, macamides, tliio- hydantoins, and some alkaloids may originate from glucosinolates (Esparza et al., 2015; Huang et al., 2018).

The functional properties of maca have made it popular in several places and also became a species of panacea since many properties have been attributed to its consumption. Several publications describe the beneficial effects of maca. One of them says “traditionally, maca has been used for medicinal purposes and as a source for energy, stamina, and endurance. It also has been used as an aphrodisiac and tonic for postmenopausal problems” (Balick and Lee, 2002).

Similarly, many papers claim properties attributed to traditional medicine in Peru. However, most of them lack support. For instance, Balick and Lee (2002) suggest that resurgence of interest in maca is due to its impact on postmenopausal women. However, this is difficult to believe since the expectancy of life in pre-Hispanic times was below the age of menopause. Survival beyond age 65 of a large percentage of the female population is a very recent phenomenon in terms of evolutionary tune (Pollycove et al., 2011). Several years ago, internet adverts stated “do not use maca if you have hypertension.” Science has demonstrated that maca reduces blood pressure (Stojanovska et al., 2015). We also found statements as “maca increases testosterone and it is dangerous in man suffering from prostate disease.” Scientific evidence demonstrated that maca does not modify serum testosterone levels (Gonzales et al., 2003) and red maca may reduce prostate hyperplasia (Gonzales et al., 2012) and apoptotic activity induced by Taxol and 2-methoxy estradiol in LNCaP cells (prostate cancer cell lines) was not altered with red maca treatment (Diaz et al., 2016). In the nineties of the last century, maca was popularized in Asian markets as “Andean Viagra” or “Andean Gingseng.” However, according to scientific evidence, maca does not have properties like Viagra (Gonzales and Alarcon-Yaquetto, 2017).

This chapter will be focused on the nutraceutical properties of maca as traditionally described and most of the medicinal properties as the scientific evidence has demonstrated.

BOMBON PLATEAU AND THE ORIGIN OF MACA

TOUGH CONDITIONS OF THE ANDEAN HIGHLANDS

Lepidium meyenii is a plant growing in the highlands of Peru. This plant whose hypocotyl is the edible part was botanically described in the 19th century by Wilhelm Gerhard Walpers, a German botanist. In 1843, Wilhelm Gerhard Walpers deposited the first specimen of Lepidium meyenii in the Herbarium of the Universidad Nacional Mayor de San Marcos in Lima, Pern (Meissner et al., 2015). Walpers described Lepidium meyenii from a plant growing in the southern part of Peru in Pisacoma, Chucuito at the highlands of Puno, in the Peruvian Southern Andes (Figure 10.2).

Pisacoma in the province of Chucuito, near Titicaca Lake in Peruvian Southern Andes. In this place, Gerard Walpers described the specimen denominated Lepidium meyermi Walpers

FIGURE 10.2 Pisacoma in the province of Chucuito, near Titicaca Lake in Peruvian Southern Andes. In this place, Gerard Walpers described the specimen denominated Lepidium meyermi Walpers.

This description, however, generates some doubts about what we know about maca today and what is traditionally known about rnaca. The name of “maca” was presented to the literature by the Spaniard chroniclers in the 16th century. Probably the first description of maca in the Bombon plateau was written by Pedro Cieza de Leon in 1554. In his book Chronicles of Peru, he described the province of Chinchaycocha (currently Carhuamayo and Junin). He describes this place as “this land is flat or level, very cold and mountains are some distance from the lake.” He distinguishes a lake “which is more than ten leagues round.” (Cieza de Leon, 1554). At that time, the lake was called Lake of Chinchaycocha or Lake of Bombon (currently named as Lake of Junin) (Figure 10.3). Natives are considered veiy warlike and they never were conquered by the Incas. Maize, abundant food in Peru, did not grow so much in Chinchaycocha and natives used roots as food. It is considered that these roots are hypocotyls of maca. However, Cieza de Leon never used the name “maca” in his chronicles.

Junin Lake. Around the lake, maca is cultivated in Junin, Peru over 4000 m of altitude

FIGURE 10.3 Junin Lake. Around the lake, maca is cultivated in Junin, Peru over 4000 m of altitude.

The name “maca” referring to the hypocotyls, we now know in Junin and Pasco, was first described in 1549 when Juan Tello Sotomayor was named by Pedro de la Gasca as Spanish Encomendero. Pedro de la Gasca asked Juan Tello Sotomayor to receive potatoes and maca as a kind of tribute by the natives of Chinchaycocha.

From the Spaniard chroniclers, we knew that maca harvest was focalized in the Peruvian Central Andes particularly in Bombon plateau, currently known as districts of Junin and border of Pasco. This place is located at 300 km from Lima, the capital of Peru, and includes the Departments of Junin and Pasco and it is far from the place in which G. Walpers described botanically Lepidium meyenii (Figure 10.3). Morphologically, Lepidium meyenii described by G. Walpers in Pisacoma, Puno represents a plant with a small hypocotyl, whereas the plant in the central highlands has succulent hypocotyl (Figures 10.4 and 10.5).

Hypocotyl of maca, the edible part of the plant

FIGURE 10.4 Hypocotyl of maca, the edible part of the plant.

Traditionally, maca is known to be used as a crop and also to treat infertility and as an energizer (Cobo, 1956; Ruiz, 1952; Vasquez de Espinoza, 1969). The chroniclers Vasquez de Espinoza and Cobo described maca in 1628 and 1653, respectively, whereas Botanist Hipolito Ruiz described maca from Carhuamayo in the 18th century. Other properties are attributed to maca but only fertility and energy-boosting properties were reported by chroniclers.

Nowadays, it is common to distinguish maca properties by the color of the hypocotyl. Several publications state that red maca, yellow maca, and black maca have different biological properties that were not described traditionally. Therefore, the knowledge about the differential properties of the different phenotypes of maca constitutes a contribution of scientific endeavor (Gonzales et al., 2010; Gonzales-Arimborgo et al., 2016).

Two vouchers deposited in the herbarium of the Universidad Nacional Mayor de san Marcos in Lima, Peru

FIGURE 10.5 Two vouchers deposited in the herbarium of the Universidad Nacional Mayor de san Marcos in Lima, Peru. In the right part is the specimen deposited by Gerhard Walpers from Pisacoma, whereas the second at the left part of the figure is a specimen collected in the central Andes. The morphological difference is clear. (Source: Courtesy of Meissner et al., 2015).

The use of gas chromatography-mass spectrometry analysis in the hypocotyls of three maca phenotypes allowed us to identify 79 compounds. Among them, 62 chemical compounds have distinct profiles among three maca phenotypes (Chen et al., 2018). Recently, it has been demonstrated that compounds present in maca may have different and antagonist properties (Fano et al., 2017; Inoue et al., 2016).

HARVESTING ATTEMPTS AROUND THE GLOBE

Maca is original from Peru, but due to its reported properties, there have been different harvesting attempts in other parts of the world. Most have failed (Lebeda et al., 2003; Marthe et al., 2003; Melnikovova et al., 2012). However, in the last decade, several publications refer that maca is also cultivated in China using Peruvian maca seeds. One of the places described in China in which maca grows is Yunnan (Feng et al., 2009; Zhang et al., 2015).

Zhang et al. (2015) published a paper comparing eight minerals in Peruvian and Chinese maca. Since mineral content in the maca hypocotyls will depend on the soil, Peruvian maca has low or nil sodium but a high amount of potassium (Valerio and Gonzales, 2005). Although maca cultivated in China used seeds from Peru, the mineral content of the hypocotyls was different from Peruvian maca. This is probably due to the quality of the soil. Sodium content was high in hypocotyls from China. This cation may become toxic for the plant (Kronzucker et al., 2013). No data on potassium content in maca from China were presented. This is very important since food containing sodium could be inadequate for subjects suffering from hypertension. Peruvian maca after consumption may reduce arterial blood pressure (Stojanovska et al., 2015). This is probably due in part to the low sodium and high potassium contents of Peruvian maca hypocotyls (Valerio and Gonzales, 2005). A healthy diet is based on the intake of low-sodium-containing food (Mendez et al., 2014).

Other concerns were the elevated amounts of copper (Cu) and nickel (Ni) in Chinese maca. Both are excessively high over recommended values. Although these minerals could be functionally important, they become toxic when present in high amounts. This could be dangerous for health and might be related to the reported high metal pollution of Chinese farmland soil (Zhang et al., 2015).

The functional primary role for copper is catalytic, with many copper metalloenzymes acting as oxidases to achieve the reduction of molecular oxygen. The recommended dietary allowance for adults is 900 pg/day (Institute of Medicine (US) Panel on Micronutrients, 2001). High consumption of copper may produce liver damage. In maca from China, copper content amounted up to 31,000 pg/kg dw, whereas it was absent in Peruvian maca.

Elevated contents of nickel (Ni) in soils and foodstuffs can threaten human health. As the content of this metal in soil, water, and food may vary from place to place, the associated risks will also be different (Yeganeh et al., 2013). This is particularly important in China since food safety is regarded as one of its main concerns in public health (Zhang et al., 2015). Comparing among different food commodity groups, nickel concentrations are highest in nuts and legumes (128 and 55 pg/100 g, respectively). A previous study showed a potential health risk from nickel via dietaiy intake of foodstuffs for Chinese consumers (Feng et al., 2009). The content of nickel in Chinese maca as that in Yunnan, ranging from 4500 (Zhang et al., 2015) to 11,300 pg/kg dw (Wang et al., 2014) must be considered as the highest among foodstuffs and must be of concern, particularly in the Chinese population (Feng et ah, 2009).

APPELLATION OF ORIGIN: MACA JUNIN

Since the first description of maca by chroniclers of the Spaniard conquest, maca has been focalized in Carhuamayo, Ondores, Junin, and Ninacaca. These places belong to the current Departments of Junin and Pasco in the Peruvian Central Andes. The description of the biological properties in the Chronicles is referred to maca from Carhuamayo. In the eighties of the 20th century, maca harvest was focalized in the Departments of Junin and Pasco, although some production was from Castrovirreyna, Huancavelica, and other places in the Central and Northern Andes. Currently, the highest maca production is observed in the Junin-Pasco Region. San Bias in Junin (currently, Ondores), is the place where evidence of first maca cultivation was found with a date of 600 years before Christ. Additionally, most of the scientific studies have been performed using maca from Carhuamayo, Junin (Junin), and Ninacaca (Pasco).

For these reasons, the National Institute for the Defense of Competition and Intellectual Property (INDECOPI), a Peruvian institution, conceded to Maca, Junin-Pasco as an appellation of origin (INDECOPI, 2001).

 
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