## 4 Discussion
### Non-Targeted LC-QTOF-MS Based Metabolomics Data Analysis
#### 4.2.1 N-Containing Products  
Approximately 24,000 known metabolites are considered part of the group of N-containing compounds [66; 68]. These include alkaloids (21,000 known metabolites), amines, non-protein amino acids, cyanogenic glycosides, glucosinolates, alkamides, lectins, peptides, and polypeptides.  
Alkaloids can be defined as nitrogen-containing compounds derived from secondary, or specialized, metabolism. Their nitrogen compound is derived from an amino acid, and they are part of a complex ring structure [69]. Although there is an immense diversity of alkaloids, they all share a biosynthetic origin, derived from the formation and reactivity of the iminium cation. Its transition from primary to secondary metabolism is considered the most important as it opens the door to a new chemical space [54]. The first of the four stages found in alkaloid biosynthesis consists of the accumulation of an amino precursor from amino acid metabolism; these amino precursors can be divided into two categories: polyamines derived from lysine, arginine, and ornithine or aromatic amines derived from tryptophan and tyrosine. In the first case, polyamides are produced through the Krebs cycle pathway, which generates aspartate as a precursor of lysine and pyrimidines, as well as glutamate, which functions as a precursor of ornithine, arginine, and non-protein amino acids [66]. In the second case, the aromatic amines come from the shikimate pathway, which produces chorismate as a precursor, on one hand from arogenate to produce tyrosine and phenylalanine and on the other hand from anthranilate to produce tryptophan [66] (Figure 6). Tyrosine is the precursor to multiple alkaloid families, including the benzylisoquinolines, the amaryllidaceae alkaloids, and the betalains.  
LC-QTOF-MS data revealed that neurine and cannabisire are two alkaloids present in the leaves of the plant, in addition to their previously reported presence in the root of samples collected in Mexico [12; 70]. These cannabis alkaloids have demonstrated antiparasitic, antipyretic, antiemetic, antitumor, diuretic, and analgesic properties [11; 71]. Neurine can be biosynthesized from choline [72], which has been classified as an essential nutrient for humans, and additionally, it is a precursor of the osmoprotectant glycine betaine, an enhancer of osmotic resistance in the plant against drought and salinity [73]. Choline biosynthesis is thus a potential nutraceuticalal pathway by which 3 methylation reactions occur, catalyzed in parallel by the cytosolic enzyme phosphoethanolamine N-methyltransferasease (EC 2.1.1.103)and mediating the next 2 methylations to produce phosphocholine [73]. Other N-containing compounds obtained in the LC-QTOF-MS data were glyceryl lactopalmitate, which is used in the food industry as an emulsifier [74] and belongs to the pyrazole-type alkaloids from ornithine. Another compound identified was piperciting, which has proven insecticidal activity [75] and can be obtained from lysine.  
In plants, between 20 and 30% of fixed carbon is invested in the synthesis of phenylalanine and then converted into lignin, which fulfills different roles in structural function as the most abundant compound in the cell wall, ultraviolet protection, signaling, and reproduction thanks to volatile anthocyanins and phenylpropanol/benzenoid [76]. The latter is the second largest group of volatiles in plants, and they are divided into three classes according to their carbon backbone: benzenoids (C6-C1), phenylpropanoids (C6-C3), and phenylpropanol-related compounds (C6-C2) [77]. Their biosynthesis is based on the amino acid-derivative pathways of shikimic acid (E.C. 1.1.1.25), which consists of seven reactions catalyzed by six enzymes and transforms phosphoenolpyruvate (PEP) with erythrose 4-phosphate (E4P) to chorismite (Figure 6).