The lignans are a large group of low molecular weight found in , particularly seed, , and vegetables.[From lign- (Latin, "wood") + -an (chemical suffix).] Lignans are precursors to .
Biosynthesis and metabolism
Lignans and lignin differ in their molecular weight, the former being small and soluble in water, the latter being high polymers that are undigestable. Both are substances derived by oxidative coupling of . Thus, most lignans feature a C18 cores, resulting from the dimerization of C9 precursors. The coupling of the lignols occurs at C8. Eight classes of lignans are: "furofuran, furan, dibenzylbutane, dibenzylbutyrolactone,
aryltetralin, arylnaphthalene, dibenzocyclooctadiene, and dibenzylbutyrolactol."
Many lignans are metabolized by mammalian gut microflora, producing so-called .
Food sources
and contain high levels of lignans.[ Lignans are not present in seed oil, and their contents in whole or ground seeds may vary according to geographic location, climate, and maturity of the seed crop, and the duration of seed storage.][
]
Secoisolariciresinol and matairesinol were the first plant lignans identified in foods.[ Typically, lariciresinol and pinoresinol contribute about 75% to the total lignan intake, whereas secoisolariciresinol and matairesinol contribute only about 25%.]
Foods containing lignans:
|
|
| 85.5 mg per oz (28.35 g) |
| 11.2 mg per oz |
| 0.3-0.8 mg per half cup (125 ml) |
| 0.2 mg per half cup |
Prevalence and health effects
Lignans are the principal source of dietary in typical , even though most research on phytoestrogen-rich diets has focused on soy isoflavones. Lignan's enterolignan products enterodiol and enterolactone have weak estrogenic activity, but they may also exert biological effects through non-estrogenic means.
A 2021 review found that lignans have a positive effect on lipid profiles of patients with dyslipidemia related diseases.
See also
External links
