Everything about The Lignan totally explained
The
lignans are a group of
chemical compounds found in
plants, particularly in flax seed. Lignans are one of the major classes of
phytoestrogens, which are
estrogen-like chemicals and also act as
antioxidants. The other classes of
phytoestrogens are the
isoflavones, and
coumestans. Plant lignans are poly
phenolic substances derived from
phenylalanine via
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.
Many natural products, known as
phenylpropanoids, are built up of C6C3 units (a propylbenzene skeleton
1) derived from cinnamyl units just as
terpene chemistry builds on
isoprene units. Structure
3 is a neolignan.
Some examples of lignans are
pinoresinol,
podophyllotoxin, and
steganacin.
When part of the human diet, some lignans are metabolized to form mammalian lignans known as
enterodiol (
1) and
enterolactone (
2) by intestinal
bacteria. Lignans that can be metabolized to form mammalian lignans are
pinoresinol,
lariciresinol,
secoisolariciresinol,
matairesinol,
hydroxymatairesinol,
syringaresinol and
sesamin.
Food sources
Flax seed and
sesame seed are among the highest known sources of lignans. The principal lignan precursor found in flaxseed is
secoisolariciresinol diglucoside. Other sources of lignans include cereals (
rye,
wheat,
oat,
barley),
pumpkin seeds,
soybeans,
broccoli, beans, and some berries.
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%. This distribution may change as the contributions of syringaresinol and hydroxymatairesinol have not properly been quantified in foods.
Sources of lignans:
| Source |
mount per 100 g |
| Flaxseed |
0.3 g |
| Sesame seed |
29 mg |
| Brassica vegetables |
185 - 2321 µg |
| Grains |
7-764 µg |
| Red wine |
91 µg |
| Cola |
0 |
A recent study 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 |
inoresinol |
yringaresinol |
esamin |
ariciresinol |
ecoisolariciresinol |
atairesinol |
ydroxymatairesinol |
| 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 |
Further Information
Get more info on 'Lignan'.
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