Beneficial Effects Of Phytoestrogens Research Articles

The potentials of Phytoestrogen compounds in aquaculture – a review

Abstract All organisms require the ability to engage in either sexual or asexual reproduction in order to ensure their own survival. In aquaculture, when one sex outgrows the other faster, farmers use hormones to stimulate growth. Furthermore, the production of fish based on sexual dimorphism is predominantly executed through the utilization of estrogens and androgens. Environmentally, these compounds may pollute the ecosystem and cause endocrine system alterations that cause harmful effects; thus, they must be handled carefully to assure environmental, biological, and food safety. Phytoestrogens as natural non-steroidal phenolic plant chemicals that resemble 17-β-estradiol, could be employed as a safe alternative source of natural estrogens. The phytoestrogens have many biological effects due to their ability to compete with estrogen receptors, but they may negatively affect fish production, reproduction, and behaviors under controlled conditions. Thus, the current literature emphasizes on the beneficial effects of phytoestrogens on aquatic animal performance, behaviors, and some reproductive features.

Dietary Phytoestrogens: Neuroprotective Role in Parkinson's Disease.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by progressive damage of mesencephalic dopaminergic neurons of the substantia nigra and the striatal projections. Recent studies suggest that estrogen and estrogen-like chemicals have beneficial effects on neurodegenerative diseases, particularly PD. Animal studies demonstrate that estrogen influences dopamine's synthesis, release, and metabolism. In vivo studies have also shown the significant beneficial effects of estrogen in shielding the brain from neurodegenerative processes like PD. Moreover, the expression and function of dopamine receptors can be modified by estrogen. Phytoestrogens are non-steroidal compounds derived from plants present in a large spectrum of foods, most specifically soy and in numerous dietary supplements. Phytoestrogens share structural and functional similarities with 17β-estradiol and can be used as an alternative treatment for PD because of estrogen's undesirable effects, such as the increased risk of breast and endometrial cancer, ischemic disorders, and irregular bleeding. Despite the beneficial effects of phytoestrogens, their impact on human health may depend on age, health status, and even the presence or absence of specific gut microflora. In addition to their antioxidant properties, soy products or phytoestrogens also exhibit neuroprotective activity in patients with PD via the interaction with estrogen receptors (ER) α and β, with a higher affinity for ERβ. Phytoestrogens offer a valuable model for fully exploring the biological effects of endocrine disruptors in general. However, observational studies and randomized controlled trials in humans have resulted in inconclusive findings within this domain. This review considered the evidence in animal models and human epidemiological data as to whether developmental exposure to various phytoestrogen classes adversely or beneficially impacts the neurobehavioral programming in PD.

Phytoestrogens: Dietary Intake, Bioavailability, and Protective Mechanisms against Colorectal Neoproliferative Lesions.

Phytoestrogens are natural substances that have been extensively studied for their beneficial effect on human health. Herein, we analyzed the data of the literature on the role of phytoestrogens in the prevention of colorectal neoproliferative lesions (CNL). Both in vitro and in vivo studies suggest that the beneficial effects of phytoestrogens on CNL mainly depend on their ability to bind estrogen receptor beta (ERβ) in the intestinal mucosa and counter ER-alpha (ERα) activity. Epidemiological data demonstrate a correlation between the low prevalence of CNL in Eastern populations and the consumption of soy products (phytoestrogen-enriched diet). However, both observational and interventional studies have produced inconclusive results. In our opinion, these discrepancies depend on an inadequate evaluation of phytoestrogen intake (dietary questionnaires were not aimed at establishing phytoestrogen intake) and absorption (depending mainly on the intestinal microbiota of the analyzed subjects). For this reason, in the present review, we performed an overview of phytoestrogen dietary intake and metabolism to offer the reader the opportunity for a better interpretation of the literature. Future prospective trials focusing on the protective effect of phytoestrogens against CNL should take into account both their dietary intake and absorption, considering the effective role of the intestinal microbiota.

Evaluation of the Anxiolytic Effect of Vitex agnus-castus on Female Mice and Possible Role of Estrogen Receptors

Background: Vitex agnus-castus is a source of phytoestrogens and is used traditionally in the treatment of premenstrual syndrome. The beneficial effects of phytoestrogens on anxiety have been shown in some studies. Objectives: In this research, we aimed to evaluate the anxiolytic activity of hydroalcoholic V. agnus-castus extract in animal models. Methods: For analyzing the antianxiety effects of the extracts, the elevated plus-maze test was applied. Thirty minutes before the test, different doses of V. agnus-castus (25, 50, and 100 mg/kg) were administered to mice. Diazepam and saline were used as the positive and negative controls, respectively. Tamoxifen was used as an antagonist of estrogen receptors to clarify the role of estrogen. Results: The time spent in the open arms increased at all doses of V. agnus-castus, while entries to closed arms reduced than the controls. Groups which received tamoxifen or a combination of tamoxifen with a high dose of V. angus-castus did not show any anti-anxiety effects. Conclusions: V. agnus-castus extract exhibited anti-anxiety effects and can be used in the treatment of the anxiety behaviors. Phytoestrogens from V. agnus-castus interact with estrogen receptors, which may be the underlying mechanism of its anxiolytic activity.

Beneficial effects of phytoestrogens and their metabolites produced by intestinal microflora on bone health

Phytoestrogens are a class of bioactive compounds derived from plants and exert various estrogenic and antiestrogenic effects. Estrogen deficiency osteoporosis has become a serious problem in elderly women. The use of ovariectomized (OVX) rat or mice models to simulate the postmenopausal condition is well established. This review aimed to clarify the sources, biochemistry, absorption, metabolism, and mode of action of phytoestrogens on bone health in intervention studies. In vitro, phytoestrogens promote protein synthesis, osteoprotegerin/receptor activation of nuclear factor-kappa B ligand ratio, and mineralization by osteoblast-like cells (MC3T3-E1). In the OVX murine model, administration of phytoestrogens can inhibit differentiation and activation of osteoclasts, expression of tartrate-resistant acid phosphatase, and secretion of pyridinoline compound. Phytoestrogens also enhance bone formation and increase bone mineral density and levels of alkaline phosphatase, osteocalcin, osteopontin, and α1(I) collagen. Results of mechanistic studies have indicated that phytoestrogens suppress the rate of bone resorption and enhance the rate of bone formation.

Les alternatives au traitement hormonal substitutif de la ménopause : le point épidémiologique

Recent results put into question the risks/benefits ratio of hormone replacement therapy and emphasize the importance of precise knowledge of the effects of other treatments that exist for postmenopausal symptoms or diseases. Our aim is to analyze their effect. A review of randomized trials or epidemiological studies was undertaken. Bisphophonates, calcitonin, parathormone, strontium ranelate, calcium and vitamin D have specific effects on bone. The efficacy of bisphophonates for prevention and treatment of osteoporosis has been proven and parathormone and strontium ranelate seem promising. These treatments are useful for women at high risk of osteoporosis who do not suffer from menopausal symptoms. Tibolone, SERMs and phytoestrogens exert effects on various tissues. SERMs are very promising, but they do not improve climacteric symptoms and their long term effects are still unknown. Tibolone has beneficial effects on climacteric symptoms and on bone loss, but recent results concerning its effects on the risk of breast cancer call into question its interest. The beneficial effects of phytoestrogens on bone and on vasomotor symptoms need to be confirmed. At this time, none of the existing treatments for postmenopausal symptoms or diseases is ideal. The existence of several options for treatments of symptoms or diseases of the postmenopause is helpful as it affords several choices for physicians and for women who sometimes need to be treated for many years. However several questions remain unanswered concerning the long term effects of these treatments.

Toxicity vs. beneficial effects of phytoestrogens

Phytoestrogens are nonsteroidal plant-derived compounds possessing estrogenic activity. These include two major classes: isoflavonoids and lignans. Phytoestrogens have received recently great attention because of their beneficial effects, which include the prevention of cancer, atherosclerosis, and bone density loss. However, they have estrogenic activity and may affect as endocrine disruptors. In this review, we pay attention to both the toxic and beneficial effects of phytoestrogens. Epidemiological data support that isoflavonoids help prevent cancer of breast, prostate, stomach, and lung. However, there have been some reports about a positive association between some phytoestrogens (e.g., campesterol and stigmasterol) and prostate cancer risk. Animal experiments and in vitro experiments have shown that the biological effects of phytoestrogens may be organ-specific, inhibiting cancer development in some sites, yet showing no effect or an enhancing effect on tumorigenesis at other sites. Also, their effects may be dependent on the timing and duration of exposure. For example, several studies in rodents have established that the favorable effect of an isoflavone-rich diet on breast cancer risk may be significant only if consumption occurs before puberty or during adolescence. On the other hand, prenatal exposure of genistein was reported to have a carcinogenic effect on the uterus of rodents. Phytoestrogen, especially soy products, has been used as hormone-replacement therapy, reducing such symptoms as hot flashes, vaginal dryness, and mood changes while protecting women from osteoporosis and heart disease. However, the animal data suggest that the timing of exposure to such compounds is crucial, with neonatal exposure having the most pronounced effects. Given the exposure of neonates to phytoestrogens, this should be a cause for concern.

Dietary Estrogen Protects Against NaCl-Sensitive Hypertension in Estrogen-Depleted Female Spontaneously Hypertensive Rats.

P169 In male spontaneously hypertensive rats (SHR) a high NaCl diet produces a rapid and sustained increase in hypertension. In contrast, in female SHR a high NaCl diet causes only a small, transient increase in arterial pressure. Elimination of most endogenous estrogen (via ovariectomy) produces mild NaCl-sensitive hypertension in female SHR, but simultaneous ovariectomy and elimination of exogenous dietary plant estrogens (phytoestrogens) nearly quadruples the hypertensive effect of the high NaCl diet, although phytoestrogen removal has a negligible effect on blood pressure in SHR fed a basal NaCl diet. This suggests that phytoestrogens (particularly genistein, the primary dietary phytoestrogen) protect ovariectomized female SHR from NaCl-sensitive hypertension. However, other reports suggest that the beneficial effects of phytoestrogens may only be present when genistein is combined with a high soy diet. The present study tests the hypothesis that genistein can independently reduce NaCl-sensitive hypertension in estrogen-depleted female SHR. Female SHR were ovariectomized at 3 weeks of age and placed on one of four casein-based, non-soy containing, diets (AIN-76A), i.e., a high (8%) or basal (0.6%) NaCl diet with or without genistein (0.06%; the approximate phytoestrogen concentration in the diet) added to the diet. After 5 weeks, femoral arterial catheters were implanted and 3 days later arterial pressures were recorded from all rats. The high NaCl diet increased arterial pressure by 68 ± 6 mm Hg in the phytoestrogen-free SHR, but produced only a 17 ± 5 mm Hg rise in arterial pressure in the genistein-supplemented group (similar to the rise previously observed in ovariectomized SHR fed a normal high NaCl diet). These results demonstrate that dietary genistein reduces NaCl-sensitive hypertension in ovariectomized female SHR. This work was supported by NHLBI Grant HL-37722.

Dietary Estrogen Protects Against NaCl-Sensitive Hypertension in Estrogen-Depleted Female Spontaneously Hypertensive Rats.

P169 In male spontaneously hypertensive rats (SHR) a high NaCl diet produces a rapid and sustained increase in hypertension. In contrast, in female SHR a high NaCl diet causes only a small, transient increase in arterial pressure. Elimination of most endogenous estrogen (via ovariectomy) produces mild NaCl-sensitive hypertension in female SHR, but simultaneous ovariectomy and elimination of exogenous dietary plant estrogens (phytoestrogens) nearly quadruples the hypertensive effect of the high NaCl diet, although phytoestrogen removal has a negligible effect on blood pressure in SHR fed a basal NaCl diet. This suggests that phytoestrogens (particularly genistein, the primary dietary phytoestrogen) protect ovariectomized female SHR from NaCl-sensitive hypertension. However, other reports suggest that the beneficial effects of phytoestrogens may only be present when genistein is combined with a high soy diet. The present study tests the hypothesis that genistein can independently reduce NaCl-sensitive hypertension in estrogen-depleted female SHR. Female SHR were ovariectomized at 3 weeks of age and placed on one of four casein-based, non-soy containing, diets (AIN-76A), i.e., a high (8%) or basal (0.6%) NaCl diet with or without genistein (0.06%; the approximate phytoestrogen concentration in the diet) added to the diet. After 5 weeks, femoral arterial catheters were implanted and 3 days later arterial pressures were recorded from all rats. The high NaCl diet increased arterial pressure by 68 ± 6 mm Hg in the phytoestrogen-free SHR, but produced only a 17 ± 5 mm Hg rise in arterial pressure in the genistein-supplemented group (similar to the rise previously observed in ovariectomized SHR fed a normal high NaCl diet). These results demonstrate that dietary genistein reduces NaCl-sensitive hypertension in ovariectomized female SHR. This work was supported by NHLBI Grant HL-37722.