Differentiation of Lepidium meyenii (Maca) from Different Origins by Electrospray Ionization Mass Spectrometry with Principal Component Analysis

Non-invasive prediction of maca powder adulteration using a pocket-sized spectrophotometer and machine learning techniques

Discriminating different cultivars of maca powder (MP) and detecting their authenticity after adulteration with potent adulterants such as maize and soy flour is a challenge that has not been studied with non-invasive techniques such as near infrared spectroscopy (NIRS). This study developed models to rapidly classify and predict 0, 10, 20, 30, 40, and 50% w/w of soybean and maize flour in red, black and yellow maca cultivars using a handheld spectrophotometer and chemometrics. Soy and maize adulteration of yellow MP was classified with better accuracy than in red MP, suggesting that red MP may be a more susceptible target for adulteration. Soy flour was discovered to be a more potent adulterant compared to maize flour. Using 18 different pretreatments, MP could be authenticated with R2CV in the range 0.91-0.95, RMSECV 6.81-9.16 g/,100 g and RPD 3.45-4.60. The results show the potential of NIRS for monitoring Maca quality.

Lepidium meyenii (Maca) Roots: UPLC-HRMS, Molecular Docking, and Molecular Dynamics

Lepidium meyenii or Maca is widely cultivated as a health care food supplement due to its nutritional and medicinal properties. Although there are a few in-depth studies evaluating Maca antihypertensive effects, the correlations between the chemical constituents and bioactivity of the plant have not been studied before. Thus, the roots were extracted using different solvents (aqueous, methanol, 50% methanol, and methylene chloride) and investigated for their antihypertensive and antioxidant activities through several in vitro assays. The methanolic extract exhibited the best renin and angiotensin converting enzyme (ACE) inhibitory activities with IC₅₀ values of 24.79 ± 1.3 ng/mL and 22.02 ± 1.1 ng/mL, respectively, along with the highest antioxidant activity. In total, 120 metabolites from different classes, e.g., alkylamides, alkaloids, glucosinolates, organic acids, and hydantoin derivatives, were identified in the methanolic extract using ultrahigh-performance liquid chromatography/high-resolution mass spectrometry (UPLC/HRMS). Molecular docking simulations were used to investigate the potential binding modes and the intermolecular interactions of the identified compounds with ACE and renin active sites. Glucotropaeolin, β-carboline alkaloids, succinic acid, and 2,4-dihydroxy-3,5-cyclopentyl dienoic acid showed the highest affinity to target the ACE with high docking scores (S ranging from -35.32 to -22.51 kcal mol^-1) compared to lisinopril (S = -36.64 kcal mol^-1). Interestingly, macamides displayed the greatest binding affinity to the active site of renin with docking scores (S ranging from -22.47 to -28.25 kcal mol^-1). Further, β-carbolines achieved docking scores comparable to that of the native ligand (S ranging from -13.50 to -20.06 kcal mol^-1). Molecular dynamics simulations and MMPBSA were also carried out and confirmed the docking results. Additionally, the computational ADMET study predicted that the compounds attaining promising docking results had proper pharmacokinetics, drug-likeness characteristics, and safe toxicological profiles. Ultimately, our findings revealed that Maca roots could be considered a promising candidate as an antihypertensive drug.

Comprehensive Profiling of Macamides and Fatty Acid Derivatives in Maca with Different Postharvest Drying Processes Using UPLC-QTOF-MS

Macamides are characteristically found in maca (Lepidium meyenii Walper). Fatty acid derivatives are also an important type of constituent in maca, since they not only relate to the biosynthesis of macamides in the postharvest process but also possess some bioactivities. To study their comprehensive profiles in maca tubers processed via the air-drying method, ultraperformance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) analyses were performed to identify macamide and fatty acid molecules. Their contents in maca tubers that were processed via air drying and freeze drying, respectively, were further quantified using high-performance liquid chromatography (HPLC) analyses comparing with eight macamide and three fatty acid reference standards. A total of 19 macamides (including four novel ones) and 16 fatty acid derivatives (two found in maca for the first time) were identified. Quantification analyses results showed the eight macamides with contents ranging from 31.39 to 1163.19 μg/g (on dry tuber), and fatty acids from 18.71 to 181.99 μg/g in the air-dried maca, but there were only three macamides and one fatty acid detected with very low contents (3.97-34.36 μg/g) in the freeze-dried maca. The results demonstrated that the air-drying method can increase the accumulations of macamides and fatty acids in the metabolism of maca in the postharvest process. The biosynthesis of two types of macamides, i.e., N-benzyl-oxo-octadecadienamides and N-benzyl-oxo-octadecatrienamides, was further elucidated in detail. These results provide more valuable insights into the phytochemicals of maca, which is helpful to explain its health benefits.

A review of the study of active components and their pharmacology value in Lepidium meyenii (Maca)

Lepidium meyenii (Maca) contains several active components, including alkaloids, glucosinolates, isothiocyanates, polysaccharides, polyphenols, and sterols, which make it have the traditional therapeutic uses. In this paper, we summarized the analytical progress of the active components associated with alkaloids, polysaccharides, glucosinolates, sterols, free fatty acids, flavonoids, and natural phenols in Maca by mass spectrometry (MS). Due to the effect of color and type on active components in Maca, we summarized the study of quality evaluation about Maca according to the type and the content of active components such as glucosinolates, essential oils, macamides, and macaenes by MS. Additionally, the research on the change of active components in Maca at different growth stages by MS will be beneficial to full utilization of active components in Maca and other natural resources. We reviewed the study in the visible distribution of amino acids, amide alkaloids, imidazolium alkaloids, and saccharides in Maca by imaging mass spectrometry (IMS). We also reviewed the pharmacology value associated with improvement of reproductive function, anti-stress response, anti-osteoporosis, antitumor activity, clinical research and toxicity of Maca, and so forth. Nevertheless, due to individual differences and limitations of the subjects, further high-quality studies are needed to confirm the clinical efficacy of the plant.