NMR Characterization of Lignans

Abstract

Lignans are particularly interesting secondary metabolites belonging to the phenyl-propanoid biosynthetic pathway. From the structural point of view, these molecules could belong to the aryltetralin, arylnaphtalene, or dibenzylbutyrolactone molecular skeleton. Lignans are present in different tissues of plants but are mainly accumulated in seeds. Extracts from plant tissues could be characterized by using the NMR-based approach, which provides a profile of aromatic molecules and detailed structural information for their elucidation. In order to improve the production of these secondary metabolites, elicitors could effectively stimulate lignan production. Several plant species are considered in this review with a particular focus on Linum species, well recognized as the main producer of lignans.

The Involvement of microRNAs in Plant Lignan Biosynthesis—Current View

“…The lignan—podophyllotoxin (PTOX) shows phytotoxicity; therefore, it must be stored in the vacuoles as glucosides of the PTOX-producing plant cells [ 37 ]. Lignans have been identified except seeds in flowering aerial parts [ 38 ], leaves, roots [ 39 ], fruits and vegetables [ 40 ], and wooden parts [ 41 ]. The immunohistochemical labeling allowed to localize the lignans mainly in the secondary wall of the sclerite cells of the outer integument of the seed, and very light labeling was also observed in cytoplasmic inclusions of the endosperm [ 42 ].…”

In vitro gastrointestinal bioaccessibility and colonic fermentation of lignans from fresh, fermented, and germinated flaxseed

“…27 Another possible explanation for the higher conversion of lignans in tea is that MATA can be directly converted to EL, whereas SECO needs to be converted to MATA or END prior to EL production. 53…”

“…27 Another possible explanation for the higher conversion of lignans in tea is that MATA can be directly converted to EL, whereas SECO needs to be converted to MATA or END prior to EL production. 53 The influence of inter-individual differences on the conversion of lignans to EL was further examined (Fig. 4B).…”

Dietary Phenolic Compounds—Wellbeing and Perspective Applications

“…Lignans are described in eight subtypes and are also diversified based on the presence of oxygen [44]. Lignans accumulate in all plant organs, but most are contained in the seeds, fruits, roots, and barks [45]. Flaxseed is the richest lignan source in the human diet [46].…”