What are Lignans and where can I find them?

November 09, 2015

What are Lignans and where can I find them?

The lignans are a group of chemical compounds found in plants. Plant lignans are polyphenolic substances derived from phenylalaninevia dimerization of substituted cinnamic alcohols (see cinnamic acid), known as monolignols, to a dibenzylbutane skeleton 2. This reaction is catalysed by oxidative enzymes and is often controlled by dirigent proteins

Plant lignans are co-passengers of dietary fiber, and therefore fiber-rich food items are often good sources of lignans. Flax seed andsesame seed contain higher levels of lignans than most other foods. The principal lignan precursor found in flaxseed issecoisolariciresinol diglucoside. Other sources of lignans include cereals (rye, wheat, oat and barley - rye being the richest source),soybeans, cruciferous vegetables such as broccoli and cabbage, and some fruits, particularly apricots and strawberries.[5]

Secoisolariciresinol and matairesinol were the first plant lignans identified in foods. Pinoresinol and lariciresinol are more recently identified plant lignans that contribute substantially to the total dietary lignan intakes. Typically, lariciresinol and pinoresinol contribute about 75% to the total lignan intake whereas secoisolariciresinol and matairesinol contribute only about 25%.[5] This distribution may change as the contributions of syringaresinol and hydroxymatairesinol have not properly been quantified in foods.

Sources of lignans:[6]

Source Amount per 100 g
Flaxseed 300,000 µg (0.3 g)
Sesame seed 29,000 µg (29 mg)
Brassica vegetables 185 - 2321 µg
Grains 7 - 764 µg
Red wine 91 µg

A recent study[7] shows the complexity of mammalian lignan precursors in the diet. In the table below are a few examples of the 22 analyzed species and the 24 lignans identified in this study.

Mammalian lignan precursors as aglycones (µg / 100 g). Major compound(s) in bold.

Foodstuff Pinoresinol Syringaresinol Sesamin Lariciresinol Secoisolariciresinol Matairesinol Hydroxymatairesinol
Flaxseed 871 48 not detected 1780 165759 529 35
Sesame seed 47136 205 62724 13060 240 1137 7209
Rye bran 1547 3540 not detected 1503 462 729 1017
Wheat bran 138 882 not detected 672 868 410 2787
Oat bran 567 297 not detected 766 90 440 712
Barley bran 71 140 not detected 133 42 42 541