Lignans are phytonutrients, beneficial chemical compounds found in plants – such as isoflavones – which exhibit a degree of hormone-like activity. They are found in flax seed, whole grain cereals, fruits and vegetables, and inquisitively enough, in the bark of Norwegian Spruce (Picea abies). Indeed, the latter has provided the source of much of the research behind lignans and is also the source of most commercially available lignan supplements.
Most of the research behind lignans has centered around their ability to act as precursors for enterolactone in the body, and the association between low serum levels of enterolactone and cardiovascular disease has been established in landmark studies conducted on two continents in 2002 and 2003. Also established is the fact that lignans are phytoestrogens – meaning that they are structurally similar to estrogens but in fact exhibit mild anti-estrogenic activity. It is this fact that has led to the study of lignans pertaining to breast cancer for women and prostate cancer for men, and a recent study has bolstered the research behind the latter.
British and Irish scientists at the University of Ulster, Belfast City Hospital, Cork Institute of Technology, and the University of Reading, in collaboration with AgResearch Grasslands (New Zealand’s largest Crown research institute devoted to the advancement of agricultural science) have completed a revealing in-vitro study concerning lignans. In examining the effects of lignans on a genetic level, the researchers tested the effects of enterolactone (the metabolite of lignans) on the LNCaP human prostate cancer cell line. The LNCaP line is widely used as an in-vitro model of the early stage of prostate cancer. Scientists found that a non-toxic enterolactone concentration reduced prostate tumor size by 57.5%, tumor cell metabolic activity by 55%, and prostate specific antigen (PSA) levels by 48.5%. PSA is a standard marker used to detect prostate cancer. Furthermore, enterolactone increased the rate of apoptosis (programmed cell death) of cancer cells by 833%. The scientists identified enterolactone’s anti-proliferative activity as a consequence of altering the expression of cell cycle associated genes, including MCM and CDK.
Source: McCann MJ, et al. Enterolactone restricts the proliferation of the LNCaP human prostate cancer cell line in vitro. Mol Nutr Food Res. 2008 May;52(5):567-80.
For more information see HMRLignan.
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