Glucosinolates
Key: Glucosinolate Analysis
1. Maca-GO
2. 10:1 maca extract
3. 10:1 maca extract (capsules)
4. 4:1 maca extract
5. Sinigrin – standard
6. Maca-GO
While no single constituent has been identified for the health benefits of maca, of the compounds present in maca, glucosinolates are reported to be the highest compared to others and may be a key identifier in differentiating the individual maca phenotypes (1–5).
It is well known that glucosinolates play a role in the metabolic detoxification of hormones and environmental toxicants (6,7); however, they also serve as anti-fungal, antimicrobial and have chemoprotective actions (8,9). One cell study has also suggested that glucosinolates in maca provide acetylcholinesterase inhibition activity and therefore may play a role in memory enhancement (1).
The literature varies in its report of glucosinolates, with 130-200 types identified (10–12), of which nine are proposed to be some of the most active compounds in maca phenotypes (1,13,14). Notably benzyl glucosinolate (glucotropaeolin), an aromatic glucosinolate, accounts for up to 80% of all glucosinolates found in maca (14,15).
The glucosinolate content of maca has been recognized as a marker of quality control processes in the dietary supplement industry (16,17). The amount of glucosinolates varies based on color, the post-harvesting drying methods, and the location where the maca is grown (3,4,17,18).
For example:
-
Fresh hypocotyls from Peru display higher concentrations of glucosinolates compared to the traditionally dried maca (4,17).
-
Fresh red and black maca grown in the Junín region of Peru contained ten times higher amounts of glucosinolates than fresh yellow maca (4).
-
Dry red maca from Junín displayed higher glucosinolates than dry black or yellow maca from the same region (4).
-
Dry hypocotyls grown in the Junín region of Peru contained higher levels compared to maca grown in the Ancash region of Peru (4).
-
The purple phenotype of dry hypocotyls from Ancash was higher in glucosinolates than the red, yellow, and black phenotypes from the same area (18).
-
Traditional drying methods activate the enzyme myrosinase, resulting in the breakdown of glucosinolates into isothiocyanate, nitrile, and thiocyanate, other important compounds of maca (19,20).
There is conflicting data in the literature as it relates to the glucosinolates found in maca based on the geographic location of Peru or China. One study (2) reported that maca from China had higher glucosinolate concentrations than Peruvian maca, while another study found Peruvian maca to contain higher levels than Chinese maca (5).
One analysis reported that the absolute content of glucosinolates was about 100 times higher in fresh maca hypocotyls than in other cruciferous vegetables (20). Further, the amount of glucosinolate content can vary based on the part of the plant used. For example, one study using L. peruvianum samples found the highest amount in seeds and the lowest amount in the leaf (20).
​
An independent analysis was conducted comparing the glucosinolate levels of a proprietary formulation of L. peruvianum known as Maca-GO to a control and three maca extracts [Image 1].
​
​
​
Image 2: Glucosinolate concentrations of different Lepidium peruvianum samples, including Maca-GO® a 10:1 concentrated product, and a 4:1 concentrated product (21).
Image provided by Symphony Natural Health
In this analysis, sinigrin (number 5), used as a control, is a glucosinolate found in various amounts in all plants of the Brassicaceae family (21). While nine glucosinolates have been identified in Lepidium peruvianum (1), testing often measures the total levels based on grouping the glucosinolates into two primary groups, as shown in Image 2.
The Maca-GO samples contained the two primary groups of glucosinolates, as indicated by the two dark green markers in sample numbers 1 and 6. In comparison, the 10:1 maca extract primarily concentrates one group of glucosinolates, as shown in sample numbers 2 and 3 (darker green is mostly on the top line), while the 4:1 maca extract primarily concentrates the other group of glucosinolates, as shown in sample number 4 (darker green is mostly on the bottom line).
CLINICAL PEARL
​
It is worth mentioning that glucosinolate metabolites like indole-3-carbinol (commonly referred to as I3C), diindolylmethane (known as DIM), and sulforaphane are mainly found in cruciferous vegetables (22) but are not found in appreciable levels in maca tubers. Therefore, it may be clinically beneficial to consider the therapeutic administration of both cruciferous vegetables and maca root for the different detoxification compounds they contain.
​
Author: Kim Ross, DCN
Reviewer: Deanna Minich, PhD
Last updated: February 22, 2024
References
1. Tarabasz D, Szczeblewski P, Laskowski T, PÅ‚aziÅ„ski W, Baranowska-Wójcik E, Szwajgier D, et al. The Distribution of Glucosinolates in Different Phenotypes of Lepidium peruvianum and Their Role as Acetyl- and Butyrylcholinesterase Inhibitors—In Silico and In Vitro Studies. Int J Mol Sci. 2022 Apr 27;23(9):4858.
2. Geng P, Sun J, Chen P, Brand E, Frame J, Meissner H, et al. Characterization of Maca (Lepidium meyenii/Lepidium peruvianum) Using a Mass Spectral Fingerprinting, Metabolomic Analysis, and Genetic Sequencing Approach. Planta Med. 2020 Jul 20;86(10):674–85.
3. Meissner HO, Mscisz A, Baraniak M, Piatkowska E, Pisulewski P, Mrozikiewicz M, et al. Peruvian Maca (Lepidium peruvianum) - III: The Effects of Cultivation Altitude on Phytochemical and Genetic Differences in the Four Prime Maca Phenotypes. Int J Biomed Sci. 2017 Jun;13(2):58–73.
4. Meissner HO, Mscisz A, Mrozikiewicz M, Baraniak M, Mielcarek S, Kedzia B, et al. Peruvian Maca (Lepidium peruvianum): (I) Phytochemical and Genetic Differences in Three Maca Phenotypes. Int J Biomed Sci. 2015 Sep;11(3):131–45.
5. Zhou Y, Li P, Brantner A, Wang H, Shu X, Yang J, et al. Chemical profiling analysis of Maca using UHPLC-ESI-Orbitrap MS coupled with UHPLC-ESI-QqQ MS and the neuroprotective study on its active ingredients. Sci Rep. 2017;7.
6. Minich DM, Bland JS. A review of the clinical efficacy and safety of cruciferous vegetable phytochemicals. Vol. 65, Nutrition Reviews. 2007.
7. Higdon J V., Delage B, Williams DE, Dashwood RH. Cruciferous vegetables and human cancer risk: epidemiologic evidence and mechanistic basis. Vol. 55, Pharmacological Research. 2007.
8. Yan S, Wei J, Chen R. Evaluation of the Biological Activity of Glucosinolates and Their Enzymolysis Products Obtained from Lepidium meyenii Walp. (Maca). Int J Mol Sci. 2022;23(23).
9. Fahey JW, Zalcmann AT, Talalay P. The chemical diversity and distribution of glucosinolates and isothiocyanates among plants. Phytochemistry. 2001 Jan;56(1):5–51.
10. Connolly EL, Sim M, Travica N, Marx W, Beasy G, Lynch GS, et al. Glucosinolates From Cruciferous Vegetables and Their Potential Role in Chronic Disease: Investigating the Preclinical and Clinical Evidence. Vol. 12, Frontiers in Pharmacology. 2021.
11. Ishida M, Hara M, Fukino N, Kakizaki T, Morimitsu Y. Glucosinolate metabolism, functionality and breeding for the improvement of brassicaceae vegetables. Vol. 64, Breeding Science. 2014.
12. Bhat R. Glucosinolates. In: Kour J, Nayik GA, editors. Nutraceuticals and Health Care. 1st ed. Cambridge, MA: Academic Press; 2022. p. 233–43.
13. Perez CJ, Conceição RS, Ifa DR. Chemical profiling and separation of bioactive secondary metabolites in Maca (Lepidium peruvianum) by normal and reverse phase thin layer chromatography coupled to desorption electrospray ionization-mass spectrometry. Journal of Mass Spectrometry. 2021;56(2).
14. Carvalho F V., Ribeiro PR. Structural diversity, biosynthetic aspects, and LC-HRMS data compilation for the identification of bioactive compounds of Lepidium meyenii. Vol. 125, Food Research International. 2019.
15. Piacente S, Carbone V, Plaza A, Zampelli A, Pizza C. Investigation of the tuber constituents of maca (Lepidium meyenii Walp.). J Agric Food Chem. 2002;50(20).
16. Xu Q, Monagas MJ, Kassymbek ZK, Belsky JL. Controlling the quality of maca (Lepidium meyenii) dietary supplements: Development of compendial procedures for the determination of intact glucosinolates in maca root powder products. J Pharm Biomed Anal. 2021;199.
17. Esparza E, Hadzich A, Kofer W, Mithöfer A, Cosio EG. Bioactive Maca (Lepidium meyenii) alkamides are a result of traditional Andean postharvest drying practices. Phytochemistry. 2015;116(1).
18. Meissner HO, Mscisz A, Piatkowska E, Baraniak M, Mielcarek S, Kedzia B, et al. Peruvian maca (Lepidium peruvianum): (II) phytochemical profiles of four prime maca phenotypes grown in two geographically-distant locations. International Journal of Biomedical Science. 2016;
19. Wang Y, Wang Y, McNeil B, Harvey LM. Maca: An Andean crop with multi-pharmacological functions. Vol. 40, Food Research International. 2007.
20. Li G, Ammermann U, Quirós CF. Glucosinolate contents in maca (Lepidium peruvianum Chacón) seeds, sprouts, mature plants and several derived commercial products. Econ Bot. 2001;55(2).
21. Meissner HO. The unique powers of the Maca tuber: Scientific facts behind traditional wisdom. (in German “Die Einzigartigen Krafte der Maca-Wurzel. Wissentshaftliche Facten Hinter Traditionallem Wissen”). Earth Oasis Verlag; 2014. 1–432 p.
22. Williams DE. Indoles Derived From Glucobrassicin: Cancer Chemoprevention by Indole-3-Carbinol and 3,3’-Diindolylmethane. Vol. 8, Frontiers in Nutrition. 2021.