This work aims to assess the recently established anti-inflammatory and antioxidant potential of melatonin of plant origin extracted from the plant matrix as a phytomelatonin complex (PHT-MLT), and compare its activity with synthetic melatonin (SNT-MLT) when used on its own or with vitamin C. For this purpose, a COX-2 enzyme inhibitory activity test, an antiradical activity in vitro and on cell lines assays, was performed on both PHT-MLT and SNT-MLT products. COX-2 inhibitory activity of PHT-MLT was found to be ca. 6.5 times stronger than that of SNT-MLT (43.3% and 6.7% enzyme inhibition, equivalent to the activity of acetylsalicylic acid in conc. 30.3 ± 0.2 and 12.0 ± 0.3 mg/mL, respectively). Higher antiradical potential and COX-2 inhibitory properties of PHT-MLT could be explained by the presence of additional naturally occurring constituents in alfalfa, chlorella, and rice, which were clearly visible on the HPLC-ESI-QTOF-MS fingerprint. The antiradical properties of PHT-MLT determined in the DPPH test (IC₅₀ of 21.6 ± 1 mg of powder/mL) were found to originate from the presence of other metabolites in the 50% EtOH extract while SNT-MLT was found to be inactive under the applied testing conditions. However, the antioxidant studies on HaCaT keratinocytes stimulated with H₂O₂ revealed a noticeable activity in all samples. The presence of PHT-MLT (12.5, 25 and 50 µg/mL) and vitamin C (12.5, 25 and 50 µg/mL) in the H₂O₂-pretreated HaCaT keratinocytes protected the cells from generating reactive oxygen species. This observation confirms that MLT-containing samples affect the intracellular production of enzymes and neutralize the free radicals. Presented results indicated that MLT-containing products in combination with Vitamin C dosage are worth to be considered as a preventive alternative in the therapy of various diseases in the etiopathogenesis, of which radical and inflammatory mechanisms play an important role.

Maca (Lepidium meyenii, Lepidium peruvianum) is part of the Brassicaceae family and grows at high altitudes in the Peruvian Andes mountain range (3500–5000 m). Historically, it has been used as a nutrient-dense food and for its medicinal properties, primarily in enhancing energy and fertility. Scientific research has validated these traditional uses and other clinical applications by elucidating maca’s mechanisms of action, nutrition, and phytochemical content. However, research over the last twenty years has identified up to seventeen different colors (phenotypes) of maca. The color, hypocotyl size, growing location, cultivation, and post-harvest processing methods can have a significant effect on the nutrition content, phytochemical profile, and clinical application. Yet, research differentiating the colors of maca and clinical applications remains limited. In this review, research on the nutrition, phytochemicals, and various colors of maca, including black, red, yellow (predominant colors), purple, gray (lesser-known colors), and any combination of colors, including proprietary formulations, will be discussed based on available preclinical and clinical trials. The gaps, deficiencies, and conflicts in the studies will be detailed, along with quality, safety, and efficacy criteria, highlighting the need for future research to specify all these factors of the maca used in publications.

The aim of the study was to present the fingerprint of different Lepidium peruvianum tuber extracts showing glucosinolates-containing substances possibly playing an important role in preventinting dementia and other memory disorders. Different phenotypes of Lepidium peruvianum (Brassicaceae) tubers were analysed for their glucosinolate profile using a liquid chromatograph coupled with mass spectrometer (HPLC-ESI-QTOF-MS/MS platform). Qualitative analysis in 50% ethanolic extracts confirmed the presence of ten compounds: aliphatic, indolyl, and aromatic glucosinolates, with glucotropaeolin being the leading one, detected at levels between 0–1.57% depending on phenotype, size, processing, and collection site. The PCA analysis showed important variations in glucosinolate content between the samples and different ratios of the detected compounds. Applied in vitro activity tests confirmed inhibitory properties of extracts and single glucosinolates against acetylcholinesterase (AChE) (15.3–28.9% for the extracts and 55.95–57.60% for individual compounds) and butyrylcholinesterase (BuChE) (71.3–77.2% for the extracts and 36.2–39.9% for individual compounds). The molecular basis for the activity of glucosinolates was explained through molecular docking studies showing that the tested metabolites interacted with tryptophan and histidine residues of the enzymes, most likely blocking their active catalytic side. Based on the obtained results and described mechanism of action, it could be concluded that glucosinolates exhibit inhibitory properties against two cholinesterases present in the synaptic cleft, which indicates that selected phenotypes of L. peruvianum tubers cultivated under well-defined environmental and ecological conditions may present a valuable plant material to be considered for the development of therapeutic products with memory-stimulating properties.

Using Liquid Chromatography-Mass Spectrometry (LCMS) , profiles of the two isotypes labelled under the same common name Maca deposited in the Medicinal Plant Herbarium, in Australia and Poland, but identified under two different scientific names Lepidium meyenii Walpers (L. meyenii) and Lepidium peruvianum Chacon (L. peruvianum) are presented. The two isotypes correspond to two holotypes of Peruvian medicinal herb known under the same common name "Maca", as originally deposited in the Herbarium of San Marcos University in Lima, Peru dated back to 1843 and 1990 respectively. The results demonstrate distinct differences in taxonomy, visual appearance, phytochemical profiles and DNA sequences of the two researched Maca isotypes, suggesting that the two Maca specimens are dissimilar and formal use of the term “synonymous” to L. meyenii and L. peruvianum may be misleading. On the basis of presented results the scientific name L. meyenii, used since 1843 up-today for cultivated Peruvian Maca by numerous reference sources worldwide, including Regulatory Bodies in the USA, EU, Australia and most lately in China, appears to be used in error and should be formally revised. It is concluded, that the isotype of cultivated Peruvian Maca labelled under its scientific name Lepidium peruvianum Chacon, provides all the characteristics peculiar to this historically-documented herb grown in Andean highlands, which may be linked to its traditional use and accepted functionality, confirmed in recent clinical study to be relevant to its present day use for expected dietary, therapeutic and health benefits.

In two trials, dietary and Glucosinolates’ characteristics in four Maca phenotypes have been examined with an extension into the determination of DNA sequences. Hypocotyls of the four prime phenotypes of Peruvian Maca - Lepidium peruvianum Chacon, labelled as “Yellow”, “Black”, “Red” and “Purple” were separated from mixed Maca crops cultivated in four geographically-distant locations in the Peruvian Andes at altitudes between 2,800m and 4,300 m a.s.l. It was found that at higher altitudes where Red and Purple Maca phenotypes were grown, the significantly higher (P<0.05) Glucosinolates’ concentrations, adopted as the marker of Maca physiological activity, were observed with the Purple phenotype showing the highest Glucosinolates’ content at 4,300m a.s.l., followed by the Red-coloured hypocotyls. Black Maca showed a reversal, but also a significant (P0.05) and has consistently the lowest Glucosinolates content. Thus, it is reasonable to assume that the altitude at which Red, Purple and Black phenotypes of L. peruvianum are grown, may be responsible for the variation in physiologic functionalities, leading to different than expected specific therapeutic and health benefits induced by Maca phenotypes grown at diverse altitudes. Although promising, insufficiently precise differences in DNA sequences failed to distinguish, without any reasonable doubt, four Maca phenotypes cultivated either in the same or geographically-distant locations, and harvested at different altitudes a.s.l. Further research on DNA sequences is needed, with more primers and larger number of Maca phenotypes, considering biosynthesis of secondary metabolites and adaptation pathways induced by harsh environment at altitudes where Maca is cultivated.