Phyto-oestrogens through the life cycle

Abstract

The growing interest in the role of phyto-oestrogens in human health has prompted scientists to evaluate the risk : benefit which would result from consuming high levels of these compounds at different stages of the life cycle. These compounds have been shown to exert a wide range of hormonal and non-hormonal activities in animals and in vitro, and these activities suggest plausible mechanisms for potential health effects in human subjects consuming phyto-oestrogen-rich diets. In addition, experimental and epidemiological data are available supporting the concept that phyto-oestrogen-rich diets exert physiological effects in vivo; however, their relative importance to human health remains to be elucidated. Our understanding of factors involved in their absorption and metabolism, including the role of intestinal microflora, is limited, and these factors together with dose-related effects may well be important in determining clinical efficacy.

Analytical methods to determine phytoestrogenic compounds

“…Lignan, first named by Harworth in 1941 [55], is a dimeric natural product derived by the combination of two phenylpropanoid C6-C3 units at ␤ carbon atoms. Enterodiol (11) and enterolactone (12) are the two most common mammalian lignans and have been described as the major lignans present in serum, urine, bile and seminal fluids of humans and animals, as well as 7 -hydroxyentrolactone (13) and enterofuran (14) identified more recently in human urine [56][57][58][59][60][61]. In humans and animals, two of the most common lignan precursors known to form enterodiol (11) and enterolactone (12) upon bacterial fermentation are secoisolariciresinol (16) and matairesinol (15), respectively [4,9,25,62,63].…”

“…In humans and animals, two of the most common lignan precursors known to form enterodiol (11) and enterolactone (12) upon bacterial fermentation are secoisolariciresinol (16) and matairesinol (15), respectively [4,9,25,62,63]. Enterolactone (12) can be also converted by enterodiol (11). Glycoside derivatives of matairesinol (15) 328 Q.…”

“…Chemical structures of mammalian lignans (11)(12)(13)(14) and examples of common plant lignan precursors (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25). and secoisolariciresinol (16), such as matairesinoside (18), 9, 9 -O-␤-d-diglucosylsecoisolariciresinol (19) and 4-O-␤-d-glucosylsecoisolariciresinol (20) are the major components of flaxseed and possibly the lignan precursors of enterodiol (11) and enterolactone (12). These glycoside derivatives are easily hydrolyzed and metabolized by colonic microflora to the mammalian lignans [9,62,64,65].…”

“…The dibenzylteterahydrofuran lignans shonanin (21) and burseran (22) found in flax have been also considered as lignan precursors [60,67]. The structures of mammalian lignans (11)(12)(13)(14) and examples of common plant precursors (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25) are illustrated in Fig. 3.…”

“…those of the breast, prostate and colon [1][2][3][4][5][6][7]. The major classes of phytoestrogenic compounds, which in this review will be termed phytoestrogens, are phenolic natural products of isoflavones and lignans, as well as coumestanes, flavonoids and stilbenes [8][9][10][11][12][13][14][15]. As postmenopausal estrogen treatment is associated with a lower cardiovascular disease risk, but may lead to a higher risk of endometrial cancer, breast cancer and venous thrombosis, consumption of phytoestrogens as a replacement hormone therapy has been a major area of research since these compounds were reported to decrease the risk of cardiovascular disease coupled with a lower risk of several types of cancer [16][17][18][19][20].…”