Like other amino acids, they are an important part of cell proteins. It has many similarities with tyrosine, serves as a precursor to numerous secondary metabolites: coumarins, flavonoids, isoflavonoids, stilbenes, aurones, cutin, suberin, sporopolenin, catechin, proanthocyanidins, lignan, lignins, phenylpropene and numerous alkaloids; compounds that provide the plant with mechanical strength, protection against UV radiation, resistance to diseases, pests and drought, viability of pollen grains, etc.