**3. Antioxidants in maca**

Like many other plants, maca plant contains various antioxidant compounds. The quantities of these substances vary according to the soil composition, maca ecotype, the time of harvest, the drying process and the extraction method [4]. In spite of the quantity differences, maca contains several and substantial amount of antioxidant compounds. These are especially phenols, glucosinolates, alkamides and polysaccharides. They have various functions on metabolism and antioxidant effects in scientific researches. In vitro studies, their antioxidant effects are mostly established by several methods such as the measurements of ferric reducing antioxidant potential (FRAP), hydroxyl radical scavenging ability (HRSA), lipid peroxidation inhibition ability (LPIA), 11,1-difenil-2-pikrilhidrazil (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) radical scavenging abilities of bioactive compounds.

#### **3.1. Phenols**

effects. These compounds act alone or synergistically and are consumed in plants or extractions in various forms. The antioxidant effect produced by plants in metabolism is measured by various methods. The most common methods are to determine the levels of antioxidant enzymes and free radicals. In addition, measurement methods such as physical performance and health score give information about antioxidant status. Like many plants known to have antioxidant activity, Maca contains antioxidant compounds. Due to its chemical composition, pharmacological effects and positive effects on various metabolisms, The South American maca plant has attracted both the consumers and the researchers in great demand all over the world recently. The aim of this chapter is to establish an analysis of the properties related to antioxidant activity of different kinds of maca plant and its contents from active compounds

Maca is a plant which has tuber roots underground and belongs to Brassicaceae family including also plants such as broccoli, radish, turnip, cabbage. It is supplemented in pudding, jam, beverage and yogurt based on its aromatic flavor and odor. It is traditionally consumed in daily meals by local people because of its high nutritional value, aphrodisiac, energizer and increasing fertility of them and their farm animals. The root colors are varies such red, yellow, brown, purple, black etc. (**Figure 1**). Maca is endemic in the South America. It is cultivated at high altitudes of Andes Mountains and dried in the sun and freezing cold in the natural environment to store for a long time. The dried maca is boiled in water and softened, and the water is consumed with its roots. Maca powder are added to drinks as energy source and aromatic sweetener [1]. Besides increasing interest in maca [2], and the International Plant Genetic Resources Institute announced that this local plant is neglected, under the danger of disappearing and must be protected [3]. It has positive effects on various metabolisms in laboratory animals and clinical studies. In addition, these effects and the mechanism of action have been confirmed by in vitro studies. Studies suggest that its impacts originate from antioxidant compounds such as phenols, glucosinolates, alkamides and polysaccharides. These compounds are determined by different extraction and analysis methods. Their antioxidant effects is established with factors such as free radical scavenging and cell viability invitro. In

such as: phenols, glucosinolates, alkamides and polysaccharides.

**2. Maca (***Lepidium meyenii***)**

138 Antioxidants in Foods and Its Applications

**Figure 1.** Some ecotypes of maca [2].

Depending on the structure elements and phenol rings they contain, phenols are termed. Phenolic compounds are divided into groups such as phenolic acids, flavonoids, tannins, resveratrol and lignans. They are found in the structure of many plants as nature antioxidant. They represent an antioxidant activity by, breaking chains, chelating metal ion, decomposing products of oxidation and scavenging free radicals [5]. Maca contains phenols in different quantities based on ecotype and extraction method. Total phenolic compounds in maca were mostly analyzed according to the Folin–Ciocalteu method by using gallic acid standard. The results of measurement are expressed as mg gallic acid equivalent (GAE) per gram of dried maca.

The ecotypes (hypocotyl colors) of maca influence the phenol contents and composition. Black maca has more total phenols than red and yellow maca. Despite black maca shows more antioxidant activity than red maca, the methanol extract of yellow maca presents more DPPH scavenging activity than that of black maca [6, 7]. When compared to yellow, pink, violent and lead hypocotyls, total phenols are highest in yellow maca (**Table 1**) [8]. Besides the effect of ecotype, phenol contents are influenced by the extraction methods. Hydroalcoholic extract and its fractions (petroleum ether, chloroform, ethyl acetate, n-butanol, and aqueous) of yellow maca have various levels of total phenols. But there is a positive correlation between FRAP, HRSA, LPIA and total phenol contents [9]. Campos et al. [4] analyzed the total phenols of maca with several extraction methods and identified a standard and optimal extraction method. It has been shown that ethanol concentration is more effective on total phenol extraction than temperature, liquid/solid ratio and extraction time. In addition, cooking process affects the total phenols content and also antioxidant activity. It was reported that boiled yellow maca contains 13.6 mg GAE/g while raw yellow maca has 7.8 mg GAE/g of total phenols (**Table 1**) [10]. Some studies argue that maca has the lowest amount of total phenols (5.5–7.6 mg GAE/g) in used herbs, plants and spices in South American culinary. Because of low phenol content, its FRAP, DPPH and ABTS scavenging abilities and antioxidant activity might be seem limited when compared to the others [11, 12].


**Table 1.** Phenol content of maca and its antioxidant effects.

## **3.2. Glucosinolates**

Glucosinolates (Gls) are the secondary metabolites with nitrogen and sulfur chains which many plants in Brassicaceae family contains. In the chemical structure of Gls, there are R and sulphate groups derived from amino asides. During the consumption, plant texture is damaged and myrosinase enzyme hydrolyses Gls to β-D-glucose and aglycone. By releasing sulphate, these metabolites reorganize to thiocyanate, isothiocyanate and nitrile which give the typical taste and smell of Brassicaceae plants. The main source of Gls is seeds, roots, stems and leaves of cruciferous vegetables in human diet [13–15]. The most of Gls in maca is aromatic type and glucotropaeolin. The Gls content varies by ecotype, part of maca plant, harvest time, cultivation region, drying and extraction process (**Table 2**) [8, 16–18]. Also, researchers have focused on antioxidant and anticarcinogenic effects of Gls in maca [4, 19].

or grinding influence adversely [16]. Boiling the dried maca hypocotyl before consumption increases total Gls content. Fresh hypocotyls have the highest level of Gls. The vast majority of Gls in maca is benzyl glucosinolate (>76%), also called glucotropaeolin. The other derivatives of Gls such as glucoalyssin, glucosinalbin, glucolimnanthin, 4-hydroxyglucobrassicin,

**Gls Ecotype Form Value Unit Effect Reference**

37.23

34.30

56.00

Mix Fresh Hypocotyl 475 μg/g DW Effects of drying [17]

DW

DW

DW

Effects of harvest time and drying

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Antioxidants in Maca (*Lepidium meyenii*) as a Supplement in Nutrition

Effects of extraction method, ABTS scavenging

Protect the skin against UV

μmol/g DW Effects of ecotype [8]

manufacturing process

[20]

141

[4]

[10]

[16]

Total glucosinolate Yellow Methanol extract 36.2 mmol/kg

Benzyl glucosinolate Yellow Pulverized 126 mg/100 g

Total glucosinolate Yellow Fresh Hypocotyl 28.42–

Benzyl isothiocyanate Aqueous 302 Dried Hypocotyl 83

Dried Hypocotyl 21.5

Dried Hypocotyl 17.8 Total glucosinolate Mix Fresh Hypocotyl 25.66 μmol/g DW Effects of

> Dried Hypocotyl 4.45 Seed 69.45 Powder 4.06 Mayonnaise 2.69 Liquor Tonic —

Violent 33.22–

Pink 44.1 Lead 54.78–

Benzyl glucosinolate Mix Fresh Hypocotyl 46.3 mg/g DW

**Table 2.** Glucosinolate and their derivates contents of maca (DW, dry weight).

Red 34.9 Black 31.43 Total glucosinolate NA Ethanol extract 4.06–17.81 mmol/kg

It is questionable whether or not there is a relation of Gls with ecotype of maca. Clement et al. [8] reported that there are differences in Gls between ecotypes and the lead color ecotype of maca has higher total Gls than that of yellow, pink and violent. Supporting to this, black maca has more benzyl glucosinolate than yellow and purple macas [18]. But, other researchers

4-methoxyglucobrassicin and glucoraphanin are in trace amounts [4, 8, 20].

The Gls content of maca is affected by harvest time, processes of drying and manufacturing. Total Gls content increases up to 90 days before harvest and 15 days after harvest. During traditional drying process in the open air, instable temperature and dehydration cause the tissue damage and decreasing myrosinase enzyme activity to generate Gls in hypocotyl [10, 20]. This process of freeze drying also decreases benzylglucosinolate and benzylisothiocyanate contents of maca (**Table 2**) [17]. Likewise, supplementing to food as a flavorant, encapsulating


**Table 2.** Glucosinolate and their derivates contents of maca (DW, dry weight).

**3.2. Glucosinolates**

**Ecotype Form Value (mg** 

140 Antioxidants in Foods and Its Applications

Pink 5.72 Violent 4.61–5.21 Lead 4.89–4.91

**GAE/g maca)**

Black 2.51 18.2%

Yellow Methanol extract 2.27–2.29 FRAP, HRSA, LPIA

NA Ethanol extract 3.56–9,51 Effects of extraction,

NA Fresh Hypocotyl 5.5–7.6 Dose-dependent DPPH

NA Aqueous 4.6 DPPH, ABTS, FRAP

Non-boiled 7.8

**Table 1.** Phenol content of maca and its antioxidant effects.

Red 11.6–13.6 14.11–16.23%

Black Spray-dried 13.5–17.9 DPPH scavenging 15.06–18.52% [6]

Yellow Methanol extract 1.85 DPPH scavenging 21.7% [7]

activities

Antioxidant activity

scavenging

scavenging

Yellow Boiled 13.6 Effects of cooking process Nonmeasured [10]

Yellow Fresh Hypocotyl 5.65–5.85 Effects of ecotype Nonmeasured [8]

**Effect Antioxidant activity Reference**

Various [9]

Various [4]

>10% [11]

0.434 mmol/100 ml [12]

Glucosinolates (Gls) are the secondary metabolites with nitrogen and sulfur chains which many plants in Brassicaceae family contains. In the chemical structure of Gls, there are R and sulphate groups derived from amino asides. During the consumption, plant texture is damaged and myrosinase enzyme hydrolyses Gls to β-D-glucose and aglycone. By releasing sulphate, these metabolites reorganize to thiocyanate, isothiocyanate and nitrile which give the typical taste and smell of Brassicaceae plants. The main source of Gls is seeds, roots, stems and leaves of cruciferous vegetables in human diet [13–15]. The most of Gls in maca is aromatic type and glucotropaeolin. The Gls content varies by ecotype, part of maca plant, harvest time, cultivation region, drying and extraction process (**Table 2**) [8, 16–18]. Also, researchers have

The Gls content of maca is affected by harvest time, processes of drying and manufacturing. Total Gls content increases up to 90 days before harvest and 15 days after harvest. During traditional drying process in the open air, instable temperature and dehydration cause the tissue damage and decreasing myrosinase enzyme activity to generate Gls in hypocotyl [10, 20]. This process of freeze drying also decreases benzylglucosinolate and benzylisothiocyanate contents of maca (**Table 2**) [17]. Likewise, supplementing to food as a flavorant, encapsulating

focused on antioxidant and anticarcinogenic effects of Gls in maca [4, 19].

or grinding influence adversely [16]. Boiling the dried maca hypocotyl before consumption increases total Gls content. Fresh hypocotyls have the highest level of Gls. The vast majority of Gls in maca is benzyl glucosinolate (>76%), also called glucotropaeolin. The other derivatives of Gls such as glucoalyssin, glucosinalbin, glucolimnanthin, 4-hydroxyglucobrassicin, 4-methoxyglucobrassicin and glucoraphanin are in trace amounts [4, 8, 20].

It is questionable whether or not there is a relation of Gls with ecotype of maca. Clement et al. [8] reported that there are differences in Gls between ecotypes and the lead color ecotype of maca has higher total Gls than that of yellow, pink and violent. Supporting to this, black maca has more benzyl glucosinolate than yellow and purple macas [18]. But, other researchers found out that various ecotypes have Gls in similar quantities and there is not an influence of ecotype on Gls content in maca [20].

**Macamides Ecotype From Effect Reference**

N-benzyl-9-oxo-12Z-octadecenamide NA Ethanol extract First report [22]

N-benzylhexadecanamide NA Pentane extract FAAH inhibition [21]

maca

Hexan extract First report in

wild maca

[25]

extract

extract

extract

First report [13]

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Antioxidants in Maca (*Lepidium meyenii*) as a Supplement in Nutrition

First report [24]

Antifatigue and antioxidant activities

[32, 34]

N-benzyl-5-oxo-6E,8E-octadecadienamide NA Petroleum ether

N-benzylhexadecanamide NA Petroleum ether

N-benzylhexadecanamide Yellow Petroleum ether

N-benzylhexadecanamide 5-oxo-6E,8E-octadecadienoic acid

N-benzyl-15Z-tetracosenamide

N-benzyl-9Z-octadecenamide

N-benzyloctadecanamide

N-benzyloctadecanamide N-benzyl-9Z-octadecenamide

octadecatrienamide

N-benzyl-9-oxo-12Z,15Z-octadecadienamide N-benzyl-13-oxo-9E,11E-octadecadienamide

N-(m-methoxybenzyl)-hexadecanamide

N-benzyl-(9Z,12Z)-octadecadienamide N-benzyl-(9Z,12Z,15Z)-octadecatrienamide

N-benzyl-5-oxo-6E,8E-octadecadienamide

N-benzyl-5-oxo-6E,8Eoctadecadienamide N-(3-methoxybenzyl) -9Zoctadecanamide N-benzy-(9Z,12Z)-octadecadienamide

N-benzy-(9Z,12Z,15Z)-octadecatrienamide N-(3-methozybenzyl)-(9Z,12Z,15Z)-

N-(3-methoxybenzyl)-hexadecanamide N-benzyl-15Z-tetraisocenamide N-(4-florobenzyl)-hexadecanamide N-(4-chlorobenzyl)-hexadecanamide N-benzyl-5-oxoctadecanamide

N-(4-chlorobenzyl)-5-oxoctadecanamide

N-(3-methoxybenzyl)-6-phenylhexanamide N-(3-methoxybenzyl)-6-phenylheptanamide N-(3-methoxybenzyl)-7-oxo-7-phenylheptanamide

N-(3,4-dimethoxybenzyl)-hexadecanamide Wild

N-pyridine-9Z-octadecenamide

N-benzyltetracosanamide

N-(3-methozybenzyl)-(9Z,12Z)-octadecadienamide

## **3.3. Alkamides**

Alkamides are formed by the different amine groups and the fatty acids and are natural components of many plants. Since their chemical structures are different from other alkamides, the alkamides of maca are called as the macamide. They which are maca-specific alkamides, are thought to have antioxidant effects. Chemical structures of macamides are formed by binding the phenylamine to fatty acid with an amide bond. These fatty acids range from 12 to 24 carbon atoms. In some macamides there is a methoxy group on the benzyl ring. The R group derives the macamides according to the number of carbons and chains they contain (**Figure 2**) [21, 22]. Day by day, a new macamide, its chemical structure and pharmacological effects are introduced in scientific publications. Despite their low levels, they are important markers to measure and standardize the maca's quality [22–25].

First, Muhammed et al. [23] identified N-benzyl-5-oxo-6E, 8E-octadecadienamide and N-benzylhexadecanamide which maca-specific alkamides and named them 'macamide'. The major amount of macamides in maca forms in N-benzylhexadecanamide. In addition to these two macamides, Zhao et al. [22] isolated five new macamides not reported in other Lepidium species before (**Table 3**). N-(3,4-dimethoxybenzyl)-hexadecanamide and N-benziltetracosanamide, commonly found in cultivated maca, were also detected in wild maca [25]. The cultivation region and the drying process affect the amount of macamides but the effect of ecotype is not clear [17, 26, 27]. Compared to maca grown in Peru, China and Czechia, the most of the N-benzylhexadecanamide is in that of China, then Peru and Czehia respectively. Further, macamide was not detected in maca grown in greenhouse [18, 27, 28]. However the above-mentioned studies argue that ecotype has no effect on macamide, they were reported that violent color of hypocotyl has higher total macamide than yellow, pink and lead colors of them [8]. Among black, purple and yellow hypocotyls of maca, black one contains the highest total macamide content [29].

Macamides are believed to be FAAH (fatty acid amide hydrolase) inhibitors, and also play a role like endocannabinoids in the cannabinergic synapses. Some derivatives of macamide have shown the inhibition activity of FAAH and to be a natural alternative to FAAH inhibitors to treat the neurological diseases, such as pain, epilepsy, anxiety, depression [30, 33, 53]. But some

**Figure 2.** The main structure of macamide [21].


found out that various ecotypes have Gls in similar quantities and there is not an influence of

Alkamides are formed by the different amine groups and the fatty acids and are natural components of many plants. Since their chemical structures are different from other alkamides, the alkamides of maca are called as the macamide. They which are maca-specific alkamides, are thought to have antioxidant effects. Chemical structures of macamides are formed by binding the phenylamine to fatty acid with an amide bond. These fatty acids range from 12 to 24 carbon atoms. In some macamides there is a methoxy group on the benzyl ring. The R group derives the macamides according to the number of carbons and chains they contain (**Figure 2**) [21, 22]. Day by day, a new macamide, its chemical structure and pharmacological effects are introduced in scientific publications. Despite their low levels, they are important

First, Muhammed et al. [23] identified N-benzyl-5-oxo-6E, 8E-octadecadienamide and N-benzylhexadecanamide which maca-specific alkamides and named them 'macamide'. The major amount of macamides in maca forms in N-benzylhexadecanamide. In addition to these two macamides, Zhao et al. [22] isolated five new macamides not reported in other Lepidium species before (**Table 3**). N-(3,4-dimethoxybenzyl)-hexadecanamide and N-benziltetracosanamide, commonly found in cultivated maca, were also detected in wild maca [25]. The cultivation region and the drying process affect the amount of macamides but the effect of ecotype is not clear [17, 26, 27]. Compared to maca grown in Peru, China and Czechia, the most of the N-benzylhexadecanamide is in that of China, then Peru and Czehia respectively. Further, macamide was not detected in maca grown in greenhouse [18, 27, 28]. However the above-mentioned studies argue that ecotype has no effect on macamide, they were reported that violent color of hypocotyl has higher total macamide than yellow, pink and lead colors of them [8]. Among black, purple and yellow hypocotyls of maca, black one

Macamides are believed to be FAAH (fatty acid amide hydrolase) inhibitors, and also play a role like endocannabinoids in the cannabinergic synapses. Some derivatives of macamide have shown the inhibition activity of FAAH and to be a natural alternative to FAAH inhibitors to treat the neurological diseases, such as pain, epilepsy, anxiety, depression [30, 33, 53]. But some

markers to measure and standardize the maca's quality [22–25].

contains the highest total macamide content [29].

**Figure 2.** The main structure of macamide [21].

ecotype on Gls content in maca [20].

142 Antioxidants in Foods and Its Applications

**3.3. Alkamides**


**3.4. Polysaccharides**

**Species Yields**

**(% DM)**

Polysaccharides are found in the structure of many plants and their major components. They are high molecular weight carbohydrates and formed by linking monosaccharides together with glycoside bonds. They have nutritive value and some pharmacological activities such as antifatigue, antioxidant, immunomodulator and antimicrobial etc [34–36]. Thus, polysaccharides may take a main part of components in some drugs and some food supplement [37, 38]. As a food supplement, maca also has large amount of polysaccharides which influence significant metabolism (**Table 4**). Maca polysaccharides (MP) are mostly composed of rhamnose, arabinose, glucose and galactose. Dominant components are D-GalA (D-Galacturonic Acid, 35.07%) and D-Glc (D-Glucose, 29.98%) [35]. Although the composition, the yield and the purity of MP vary according to the extraction method, the water extraction method, simple and eco-friendly, is preferred in studies to isolate them. But there are disadvantages such as the need for additional applications (ultrasonic extraction, enzymes, centrifuge, deproteinization) to increase the yield or purity of polysaccharides in maca extract [39, 26]. For example, when increasing the concentration of solvent, MP yield increases but the purity of MP decreases from 69.4 to 39.5%. Amylase and glucoamylase enzyme applications decrease both amount and purity of MP. Contrary to filtration, centrifuge enhances the yield and decrease the purity of MP [39].

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The antioxidant and antifatigue activities of MP are established by measuring some biochemical parameters in blood and tissues. When fed several doses of MP (79% of glucose), hypoxia tolerance, and exercise ability of mice and muscle glycogen were enhanced. But blood lactic acid (LA) lactic dehydrogenase (LDH) and urea nitrogen (BUN) were not affected [40]. Otherwise, it was reported that increasing in swimming time and antifatigue effects of MP are based on increasing liver glycogen and decreasing urea nitrogen, BUN, LDH, and LA of mice and rats with exercise-induced stress [35, 41, 42]. In addition to these results, MP has effects on the precursor enzymes of antioxidant status such as SOD, GPx (glutathione peroxidase) and CAT (catalase). While Tang et al. [35] have introduced that a daily dose of 100 mg MP/ kg body weight of mice significantly increased GPx and decreased MDA (malondialdehyde),

Mice 0.2 20–100 mg/kg/d Antifatigue activity [34] Mice 0.01 25–50–100 mg/kg/d Antifatigue and Antioxidant activities [35] Alcoholic Mice NA 200–800 mg/kg/d Antioxidant activity [43] Cell culture NA 0.125–2 mg/ml Increasing viability, hepatoprotectant [43] Cell culture 6 62.5–1000 μg/mL Immunomodulator activity [44] Rat 2.37 50–100–200 mg/kg/d Antioxidant activity [42] In vitro 0.052–0.15 2 mg/ml Antioxidant activity, Effect of extraction [39] Mice NA 0.1–0.5–1 g/kg/d Antifatigue activity [40] Mice 2.37 500–2000 mg/kg/d Antifatigue and Antioxidant activities [41]

**Table 4.** Polysaccharides content of maca and their antioxidant effects (DM, dry maca).

**Dose Unit Effect Reference**

**Table 3.** Macamides and macene content of maca and their effects.

macamide derivatives which has the carbonyl group do not produce the inhibition effect of the FAAH because of their interaction with the FAAH [21]. Wu et al. [30] have reported that the FAAH inhibition activity of macamides can be reversible or irreversible due to their chemical structures. When mice in exercise-induced stress was daily fed with the low (12 mg/kg) and high (40 mg/kg) doses of N-benzyloleamide, N-benzyllinoleamide and N-benzylpalmitamide, antioxidant and antifatigue effects were recorded by increasing GPx and SOD (superoxide dismutase), decreasing MDA (malondialdehyde) lactic acid, blood ammonia, LDH (lactate dehydrogenase), liver glycogen and increasing non-esterified fatty acid (NEFA) specially in N-benzyloleamide high dose group (40 mg/kg).Thus, N-benzyloleamide influences the energy metabolism and reveals antioxidant and antifatigue activities (**Table 3**) [31].

#### **3.4. Polysaccharides**

macamide derivatives which has the carbonyl group do not produce the inhibition effect of the FAAH because of their interaction with the FAAH [21]. Wu et al. [30] have reported that the FAAH inhibition activity of macamides can be reversible or irreversible due to their chemical structures. When mice in exercise-induced stress was daily fed with the low (12 mg/kg) and high (40 mg/kg) doses of N-benzyloleamide, N-benzyllinoleamide and N-benzylpalmitamide, antioxidant and antifatigue effects were recorded by increasing GPx and SOD (superoxide dismutase), decreasing MDA (malondialdehyde) lactic acid, blood ammonia, LDH (lactate dehydrogenase), liver glycogen and increasing non-esterified fatty acid (NEFA) specially in N-benzyloleamide high dose group (40 mg/kg).Thus, N-benzyloleamide influences the energy

N-benzylhexadecanamide NA NA Neuroprotective

**Macamides Ecotype From Effect Reference**

Yellow, Purple

extract

Extract

Petroleum ether extract

process

antioxidant activities

Effects of ecotype, Antioxidant activity

activity

Effects of region and greenhouse

No effect [31]

[7]

[29]

[33]

[18, 27, 28]

N-benzyl hexadecanamide Mix Methanol extract Effects of drying

N-benzyloleamide Antifatigue and

N-benzylpalmitamide No effect

N-benzyllinoleamide NA Petroleum ether

N-benzyl-9-oxo-(12Z,15Z)- octadecadienamide Mix Petroleum Ether

N-benzylhexadecanamide Black,

N-benzyl-(9Z,12Z)-octadecadienamide N-benzyl-(9Z,12Z,15Z)-octadecatrienamide

144 Antioxidants in Foods and Its Applications

N-benzyl-5-oxo-6E,8E-octadecadienamide

N-benzyl-13-oxo-(9E,11E)-octadecadienamide

N-benzyl-(9Z,12Z,15Z)-octadecatrienamide

N-benzyl-(9Z,12Z)-octadecadienamide N-(3-methoxybenzyl)-hexadecanamide

N-(3-methoxybenzyl)-(9Z,12Z,15Z)-

**Table 3.** Macamides and macene content of maca and their effects.

octadecatrienamide

N-benzyl-hexadecanamide N-Benzyl-9Z-octadecanamide N-Benzyl-octadecanamide N-Benzyl-heptadecanamide

N-(3-methoxybenzyl)-(9Z,12Z)-octadecadienamide

N-benzyl-9-oxo-12Z-octadecanamide N-(3-methoxybenzyl)-(9Z,12Z,15Z)-

octadecatrienamide

metabolism and reveals antioxidant and antifatigue activities (**Table 3**) [31].

Polysaccharides are found in the structure of many plants and their major components. They are high molecular weight carbohydrates and formed by linking monosaccharides together with glycoside bonds. They have nutritive value and some pharmacological activities such as antifatigue, antioxidant, immunomodulator and antimicrobial etc [34–36]. Thus, polysaccharides may take a main part of components in some drugs and some food supplement [37, 38]. As a food supplement, maca also has large amount of polysaccharides which influence significant metabolism (**Table 4**). Maca polysaccharides (MP) are mostly composed of rhamnose, arabinose, glucose and galactose. Dominant components are D-GalA (D-Galacturonic Acid, 35.07%) and D-Glc (D-Glucose, 29.98%) [35]. Although the composition, the yield and the purity of MP vary according to the extraction method, the water extraction method, simple and eco-friendly, is preferred in studies to isolate them. But there are disadvantages such as the need for additional applications (ultrasonic extraction, enzymes, centrifuge, deproteinization) to increase the yield or purity of polysaccharides in maca extract [39, 26]. For example, when increasing the concentration of solvent, MP yield increases but the purity of MP decreases from 69.4 to 39.5%. Amylase and glucoamylase enzyme applications decrease both amount and purity of MP. Contrary to filtration, centrifuge enhances the yield and decrease the purity of MP [39].

The antioxidant and antifatigue activities of MP are established by measuring some biochemical parameters in blood and tissues. When fed several doses of MP (79% of glucose), hypoxia tolerance, and exercise ability of mice and muscle glycogen were enhanced. But blood lactic acid (LA) lactic dehydrogenase (LDH) and urea nitrogen (BUN) were not affected [40]. Otherwise, it was reported that increasing in swimming time and antifatigue effects of MP are based on increasing liver glycogen and decreasing urea nitrogen, BUN, LDH, and LA of mice and rats with exercise-induced stress [35, 41, 42]. In addition to these results, MP has effects on the precursor enzymes of antioxidant status such as SOD, GPx (glutathione peroxidase) and CAT (catalase). While Tang et al. [35] have introduced that a daily dose of 100 mg MP/ kg body weight of mice significantly increased GPx and decreased MDA (malondialdehyde),


**Table 4.** Polysaccharides content of maca and their antioxidant effects (DM, dry maca).

Li et al. [41] have reported that MP has occurred a dose depend antioxidant activity by increasing SOD, GPx and CAT enzymes and decreasing MDA in liver of mice. Also, He et al. [42] have reported that antioxidant activity with a correlation between the doses and enzymes levels in muscle against the exercise-induced oxidative stress. Similar to animal experiments, MP plays the crucial roles of antioxidant and free radical scavenger in cell cultures (**Table 4**) [39, 43].

In brief, the mechanism of antifatigue and antioxidant effects of especially aqueous polysaccharides in maca originates from improving hypoxia tolerance, eliminating metabolic wastes, serving energy source with high glucose contents and reducing oxidative damage by enhancing antioxidant enzyme [38, 41].
