A review of flaxseed lignan and the extraction and refinement of secoisolariciresinol diglucoside

Abstract

Lignan is a class of diphenolic compounds that arise from the condensation of two phenylpropanoid moieties. Oilseed and cereal crops (e.g., flaxseed, sesame seed, wheat, barley, oats, rye, etc.) are major sources of plant lignan. Methods for commercial isolation of the lignan secoisolariciresinol diglucoside (SDG) are not well reported, as most publications describing the detection, extraction, and enrichment of SDG use methods that have not been optimized for commercial scale lignan recovery. Simply scaling up laboratory methods would require expensive infrastructure to achieve a marketable yield and reproducible product quality. Therefore, establishing standard protocols to produce SDG and its derivatives on an industrial scale is critical to decrease lignan cost and increase market opportunities. This review summarizes the human health benefits of flaxseed lignan consumption, lignan physicochemical properties, and mammalian lignan metabolism, and describes methods for detecting, extracting, and enriching flaxseed lignan. Refining and optimization of these methods could lead to the development of inexpensive lignan sources for application as an ingredient in medicines, dietary supplements, and other healthy ingredients.

Keywords:

• Flaxseed
• Linum usitatissimum L
• lignan
• secoisolariciresinol diglucoside
• secoisolariciresinol
• extraction
• refinement

Author contributions

VM and MJTR supervised, conceptualized, and designed the manuscript. YH wrote the original draft of the manuscript. TJT, YYS, SKP, and MJTR edited and revised the manuscript critically. TJT, YYS, YJK, and MJTR revised the final written manuscript. TJT and YYS prepared the figures and tables. MJTR and YYS acquired the funding for this project. All authors have read and agreed to the published version of the manuscript.

Disclosure statement

The authors are not aware of any affiliations, memberships, funding, or financial holdings that might be perceived as affecting the objectivity of this review.

Additional information

Funding

This work was supported by the Saskatchewan Agricultural Development Fund (grant numbers 20190155, 20190154, 20180281, 20180248, 20180255, 20170133); National Sciences and Engineering Research Council of Canada Discovery Grant (grant number RGPIN-2018-06631); Mitacs (grant numbers IT19122, IT16156); and Brain Pool Programs (grant numbers NRF-2019H1D3A2A01102248 and NRF-2020H1D3A2A02110965) through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT.