Alkaloids
In the 1960s, Dr. Gloria Chacón identified four alkaloids responsible for the fertility-enhancing effects of L. peruvianum (1). The bitter-tasting, nitrogen-containing, and potentially toxic alkaloids are part of the plant defense system. Several types of alkaloids have been identified in L. meyenii extracts, including, but not limited to, alkaloid amides (macamides), hydantoin derivatives (macahydantoins, meyeniihydantoins, and macathiohydantoins), hexahydroimidazothiazole derivatives (meyeniins), imidazole alkaloids known as lepidiline A, B, C, and D (2–4), and pyrrole alkaloids referred to as macapyrrolins (3,5). Preliminary cytotoxicity activity has been determined in some of these compounds in specific cell lines (6) and potential anti-inflammatory, anti-allergic, and anti-thrombotic effects, depending on the extract used (3).
Geng et al. (7) and Zhou et al. (8) reported that Peruvian maca (L. peruvianum) had higher alkaloid concentrations than maca cultivated in China.
Macamides and Macaenes
Macamides and macaenes are benzylated alkamides, which are natural compounds often used to identify maca accurately (9,10). However, macamides are considered unique to maca (11), whereas macaenes can be found in other plants such as tomatoes and eggplants (10). A review of analytical research using liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) for L. meyenii extracts reported three macaenes (C-18 fatty acid derivatives) and twenty-three macamides (fatty acid amides) (5). A slightly older study using different analytical methods (UHPLC-ESI-Orbitrap MS and UHPLC-ESI-QqQ MS) on a methanolic extract of maca cited only eleven macaenes (8).
Macamides are a unique class of maca phytochemicals, with more than thirty compounds identified and explored for their anti-fatigue effects (11,12). There is a suggestion in the scientific literature that macaene and macamide compounds could be (partly) responsible for the bioactive effects of maca on sexual performance in male animals (13,14). Macamides are also important anti-inflammatory, antioxidant, and anti-cancer compounds (10), contributing to maca’s anti-fatigue, neuroprotection, and fertility-enhancing effects (8). In mice, macamide administration helped reduce pro-inflammatory factors and reactive oxygen species after a swim test, improving markers of grip strength and extending time spent in activity (15). A recent study notes that the macamides in maca exhibit nuclear factor erythroid 2-related factor (Nrf2) activation (16). Macaenes may play a role in lipid metabolism (10).
Newer research on the science of maca phytochemicals continues, with some recent publications looking at the immunomodulatory (17) and neuroprotective (18) aspects of polysaccharides from maca, along with testing isolated compounds like a natural fatty amide known as N-benzylhexadecanamide for its ability to enhance testosterone production (19). Using proteomics and lipomics methods, the neuroprotective effects imparted by N-benzylhexadecanamide may be attributed to its effects on sphingolipid metabolism and mitochondrial function, suggesting that it could continue to be investigated for neurodegenerative diseases (20). Comparatively, this fatty acid amide is found in higher amounts in Peruvian maca than Chinese maca (21), suggesting that elevation or other factors could be responsible for its synthesis. Macamides are thought to influence mood states by modulating the endocannabinoid system and reducing the degradation of anandamide, which acts on the cannabinoid 1 (CB1) receptor (22,23).
Credit: Minich DM, Ross K, Frame J, Fahoum M, Warner W, Meissner HO. Not All Maca Is Created Equal: A Review of Colors, Nutrition, Phytochemicals, and Clinical Uses. Nutrients. 2024 Feb 14;16(4):530. doi: 10.3390/nu16040530. PMID: 38398854; PMCID: PMC10892513. https://creativecommons.org/licenses/by/4.0/.
References
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