Flax Lignans Flaxseed Hull extract Lignans SDG Oil
Secoisolariciresinol Diglycoside (SDG) Flax Lignans Flaxseed Oil EXtract Flaxseed hull EXtract Lignans SDG Linum usitatissimum Secoisolariciresinol Diglycoside
Secoisolariciresinol diglycoside, or SDG, is a plant lignan most notably found in flaxseed (linseed) . SDG is classified as a phytoestrogen since it is a plant-derived, nonsteroid compound that possesses estrogen-like activity. SDG has weak estrogenic activity. The level of SDG in flaxseed typically varies between 0.6% and 1.8%.
Lignans are one of the two major classes of phytoestrogens; the other class is the isoflavones. Plant lignans are polyphenolic substances derived from phenylalanine via dimerization of substituted cinnamic alcohols. Mammalian lignans are lignans derived from plant lignans. For example, following ingestion, SDG is converted to the aglycone secoisolariciresinol, which is then metabolized to the mammalian lignans enterolactone and enterodiol. Most of the effects of oral SDG are mediated by enterolactone and enterodiol.
The molecular formula of SDG is C32H46O16, and its molecular weight is 686.71 daltons. The aglycone of SDG is also known as 2, 3-bis (3-methoxy-4-hydroxybenzyl) butane-1, 4-diol. Enterolactone is also known as trans-2, 3-bis [(3-hydroxylphenyl) methyl]-butyrolactone. It is represented by the following structural formula:
Secoisolariciresinol diglycoside ACTIONS AND PHARMACOLOGY
SDG has estrogenic and antioxidant activities. It may also have antiestrogenic, anticarcinogenic, antiatherogenic and antidiabetic activities.
MECHANISM OF ACTION
SDG, as well as its mammalian lignan metabolites, enterolactone (EL) and enterodiol (ED) , have weak estrogenic activity as measured in in vivo and in vitro assays.
SDG, EL and ED have a number of antioxidant activities, including inhibition of lipid peroxidation and scavenging of hydroxy radicals. SDG also has anti-platelet-activation factor (PAF) activity. PAF can induce the release of reactive oxygen species from neutrophils. SDG, via its metabolite EL, has been found to inhibit estrogen synthase (aromatase) and to stimulate the synthesis of sex hormone binding globulin (SHBG) . Both of these actions could account for the possible anti-estrogen activity of SDG.
The possible anticarcinogenic, antiatherogenic and antidiabetic activities of SDG are thought to be due, in large part, to the antioxidant activities of its metabolites EL and ED.
SDG, following ingestion, is transported to the large intestine, where it is hydrolyzed by bacteria to the aglycone secoisolariciresinol. Secoisolariciresinol, in turn, is metabolized by bacteria in the large intestine to the mammalian lignans EL and ED. EL and ED are absorbed from the large intestine. Little is known about the distribution of EL and ED to the various tissues of the body. It is known that ED and EL undergo conjugation in the liver with glucuronate and sulfate. The glucuronate and sulfate conjugates of ED and EL are excreted in the urine and in the bile.
There appears to be considerable individual variation in the absorption and metabolism of the SDG metabolites ED and EL.