Daidzein impairs Leydig cell testosterone production and Sertoli cell function in neonatal mouse testes: An in vitro study

Caceres S., Peña L., Moyano G., Martinez-Fernandez L., Monsalve B., Illera M.J., Millan P., Illera J.C., Silvan G.

This study was performed to determine how two of the most important isoflavones, genistein and daidzein, affect the gonadal axis in male prepuberal rats. One hundred and seventy-five prepuberal male Wistar rats were allocated into seven groups: one control group and six experimental groups that were orally administered a high or low dose of genistein, daidzein or a mixture of both. Testosterone determination was assayed by EIA. The testes and body weights were measured, and the histology of the epididymis with the sperm content and epididymal sperm count were evaluated. In the control group, we observed an increase in the serum testosterone levels (>2.5 ng ml(-1) ) at the third week (52 days), which corresponded to the onset of puberty in these rats. The same increase in serum testosterone levels was observed at the fourth week in rats that received low doses of isoflavones; therefore, we concluded that the onset of puberty was delayed. At high doses, there was no significant increase in testosterone levels, which could be related to the fact that these male rats did not reach puberty. These findings were supported by the results obtained from the analysis of the epididymal content as well as the testes/body weight ratio.

Auger J., Eustache F., Rouiller-Fabre V., Canivenc-Lavier M., Livera G.

Jungbauer A., Medjakovic S.

Phytoestrogens are a diverse class of non-steroidal compounds that have an affinity for estrogen receptors α and β, for the peroxisome proliferator-activated receptor (PPAR) family and for the aryl hydrocarbon receptor. Examples of phytoestrogens include prenylated flavonoids, isoflavones, coumestans and lignans. Many phytoestrogens counteract the cellular derailments that are responsible for the development of metabolic syndrome. Here we propose a mechanism of action which is based on five pillars/principles. First, phytoestrogens are involved in the downregulation of pro-inflammatory cytokines, such as COX-2 and iNOS, by activating PPAR and by inhibiting IκB activation. Second, they increase reverse cholesterol transport, which is mediated by PPARγ. Third, phytoestrogens increase insulin sensitivity, which is mediated via PPARα. Fourth, they exert antioxidant effects by activating antioxidant genes through KEAP. Fifth, phytoestrogens increase energy expenditure by affecting AMP-activated kinase signaling cascades, which are responsible for the inhibition of adipogenesis. In addition to these effects, which have been demonstrated in vivo and in clinical trials, other effects, such as eNOS activation, may also be important. Some plant extracts from soy, red clover or licorice can be described as panPPAR activators. Fetal programming for metabolic syndrome has been hypothesized; thus, the consumption of dietary phytoestrogens during pregnancy may be relevant. Extracts from soy, red clover or licorice oil have potential as plant-derived medicines that could be used to treat polycystic ovary syndrome, a disease linked to hyperandrogenism and obesity, although clinical trials have not yet been conducted. Phytoestrogens may help prevent metabolic syndrome, although intervention studies will be always be ambiguous, because physical activity and reduced calorie consumption also have a significant impact. Nevertheless, extracts rich in phytoestrogens may be an alternative treatment or may complement conventional treatment for diseases linked with metabolic syndrome. This article is part of a Special Issue entitled 'Phytoestrogens'.

Lagari V.S., Levis S.

Women have always looked for non-hormonal options to alleviate menopausal vasomotor symptoms and prevent menopausal bone loss. The use of complementary and alternative medicine for these purposes has particularly increased after the publication of the Women's Health Initiative's results suggesting that there might be more risks than benefits with hormone replacement. Phytoestrogens are plant-derived estrogens that, although less potent than estradiol, bind to the estrogen receptor and can function as estrogen agonists or antagonists. Soy isoflavones extracted from soy are the phytoestrogens most commonly used by menopausal women. Because typical Western diets are low in phytoestrogens and taking into account the general difficulty in changing dietary habits, most clinical trials in Western women have used isoflavone-fortified foods or isoflavone tablets. Although some women might experience a reduction in the frequency or severity of hot flashes, most studies point towards the lack of effectiveness of isoflavones derived from soy or red clover, even in large doses, in the prevention of hot flashes and menopausal bone loss. This article is part of a Special Issue entitled 'Phytoestrogens'.

Sato T., Katagiri K., Kubota Y., Ogawa T.

The in vitro propagation of mouse spermatogonial stem cells (SSCs) became possible in 2003; these cultured SSCs were named germ-line stem (GS) cells. To date, however, it has not been possible to induce spermatogenesis from GS cells in vitro. Recently, we succeeded in producing functional sperm from primitive spermatogonia in explanted neonatal mouse testis tissues. Here we describe a protocol that can support spermatogenesis from GS cells up to sperm formation in vitro using an organ culture method. GS cells transplanted in the extracted testis form colonies in the tissue fragments and differentiate into sperm under the described in vitro organ culture conditions. It takes about 6 weeks to obtain sperm from GS cells. The sperm are viable, resulting in healthy offspring through micro-insemination. Thus, this protocol should be a valuable tool for the study of mammalian spermatogenesis.

Boberg J., Mandrup K.R., Jacobsen P.R., Isling L.K., Hadrup N., Berthelsen L., Elleby A., Kiersgaard M., Vinggaard A.M., Hass U., Nellemann C.

• High doses of a dietary relevant mixture of phytoestrogens induced endocrine disruption in rats. • Mammary gland histology was altered in adult males after perinatal exposure . • Anti-androgenic effects on anogenital distance were present in newborn males. • An excessive human intake of phytoestrogens from dietary supplements or special dietary habits may contribute to endocrine disruption following exposure during fetal life. Dietary phytoestrogens may prevent certain human diseases, but endocrine activity has been reported in animal studies. Sprague-Dawley rats were exposed perinatally to a 1-, 10- or 100-fold “high human dietary intake” mixture of 12 phytoestrogens consisting of mainly the lignan secoisolarici resinol and the isoflavones genistein and daidzein. This mixture induced persistent adverse effects, as adult male mammary glands showed hypertrophic growth. A reduced anogenital distance in newborn males indicated an anti-androgenic mode of action. Testosterone levels, testis and prostate weights, and expression of selected genes in testis and prostate were unaffected. Decreased serum estradiol was seen in genistein-exposed dams. This study indicated adverse effects at high intake levels in rats, but does not provide evidence for risk of phytoestrogen-mediated endocrine disruption at normal human dietary consumption levels. Further studies are warranted to increase the knowledge upon which risk assessment on dietary phytoestrogen exposure during pregnancy and infancy is based.

N’Tumba-Byn T., Moison D., Lacroix M., Lecureuil C., Lesage L., Prud’homme S.M., Pozzi-Gaudin S., Frydman R., Benachi A., Livera G., Rouiller-Fabre V., Habert R.

Endocrine disruptors (ED) have been incriminated in the current increase of male reproductive alterations. Bisphenol A (BPA) is a widely used weak estrogenic environmental ED and it is debated whether BPA concentrations within the average internal exposure are toxic. In the present study we investigated the effects of 10−12 to 10−5 M BPA concentrations on fetal Leydig cell function, as fetal life is a critical period of sensitivity to ED effects on male reproductive function. To this aim, fetal testes from human at 6.5–10.5 gestational weeks (GW) or from rat and mouse at a comparable critical period of development (14.5 days post-coitum (dpc) for rat and 12.5 dpc for mouse) were explanted and cultured using our validated organotypic culture system in the presence or absence of BPA for 1–3 days. BPA concentrations as low as 10−8 M reduced testosterone secretion by human testes from day 1 of culture onwards, but not by mouse and rat testes where concentrations equal to 10−5 M BPA were required. Similarly, 10−8 M BPA reduced INSL3 mRNA levels only in human cultured testes. On the contrary, 10−5 and 10−6 M diethylstilbestrol (DES), a classical estrogenic compound, affected testosterone secretion only in rat and mouse testis cultures, but not in human testis cultures. Lastly, contrarily to the DES effect, the negative effect of BPA on testosterone produced by the mouse fetal testis was maintained after invalidation of estrogen receptor α (ERα). In conclusion, these results evidenced i) a deleterious effect of BPA on fetal Leydig cells function in human for concentrations from 10−8 M upwards, ii) species-specific differences raising concerns about extrapolation of data from rodent studies to human risk assessment, iii) a specific signaling pathway for BPA which differs from the DES one and which does not involve ERα.

Yuan X., Zhang B., Li L., Xiao C., Fan J., Geng M., Yin Y.

Soybean isoflavones are structurally similar to mammalian estrogens and therefore may act as estrogen agonists or antagonists. However, it has not been determined if they have any negative effects on reproductive parameters in male livestock. Therefore, the objective of this study was to evaluate the effects of soybean isoflavones on male reproduction using Chinese mini-pig boars as a model. Fifty Xiang boars were randomly divided into five groups and fed diets containing 0, 125, 250, or 500 ppm soybean isoflavones or 0.5 ppm diethylstilbestrol for 60 days. Dietary supplementation with 250 ppm of soy isoflavones markedly increased the testis index (P < 0.05), fructose content (P < 0.05), and α-glycosidase content in testicular tissue (P < 0.01), as well as increased the number of viable germ cells (P < 0.01) and the level of Bcl-2 protein (P < 0.01). However, 500 ppm of soybean isoflavones significantly reduced both testis and epididymis indexes (P < 0.05) and lactate dehydrogenase levels (P < 0.01), as well as reduced serum LH and testosterone levels (P < 0.05). High levels of soybean isoflavones also increased malondialdehyde levels (P < 0.05), as well as increased the numbers of early and late apoptotic germ cells (P < 0.01) and the level of Bax proteins (P < 0.05) in the testis. The results of this study indicate that consumption of soy isoflavones at dietary levels up to 250 ppm did not adversely affect reproductive parameters in Chinese mini-pig boars whereas higher levels of soy isoflavones may adversely affect male reproduction.

Magee P.J., Rowland I.

Meta-analyses of epidemiological studies of soy consumption and breast cancer risk have demonstrated modest protective effects, usually attributed to isoflavones. Concern has been expressed, however, that the estrogenic activity of isoflavones may have adverse effects on breast cancer recurrence.The review covers epidemiological studies that have investigated the impact of soy consumption in breast cancer patients on recurrence and mortality. There are preliminary data to suggest that soy has differential effects on recurrence in human epidermal growth factor receptor-2 positive and human epidermal growth factor receptor-2 negative tumours. Recent studies on mechanisms of action of soy in breast cancer provide insights into epigenetic effects and the interaction of isoflavones with IGF-1 and with a number of polymorphisms of genes associated with breast cancer risk such as MDM2 and CYP1B1.Overall, these studies indicate that soy foods consumed at levels comparable to those in Asian populations have no detrimental effects on risk of breast cancer recurrence and in some cases significantly reduce the risk. Importantly, soy does not appear to interfere with tamoxifen or anastrozole therapy. Recent research suggests that women who are at increased risk of breast cancer due to polymorphisms in genes associated with the disease may especially benefit from high soy isoflavone intake.

Liu Z.-., Ho S.C., Chen Y.-., Ho Y.P.

AbstractBackground & Aims Observational studies note that regular dietary soy protein intake (6–11 g day−1) has a significant association with lower blood lipids; however, these observations have not been confirmed by clinical trials. This study aimed to ascertain the effects of moderate intake of soy protein (15 g) with isoflavones or isoflavones alone on serum lipid profiles, inflammatory markers (C-reactive protein and uric acid) and composite cardiovascular risk in Chinese postmenopausal, prediabetic women. Methods and Results A double-blind randomised, placebo-controlled trial was conducted among 180 postmenopausal Chinese women with prediabetes or early untreated diabetes, aged 46–70 years and, on average, 6.0 years since menopause. Participants were randomly assigned to one of the three arms to receive 15-g soy protein and 100-mg isoflavone (Soy group), or 15-g milk protein and 100 mg isoflavone (Iso group) or 15-g milk protein (placebo group) on a daily basis for 6 months. The results showed that no significant difference was observed in serum high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), total cholesterol (TC), triaclyglycerol (TG), high sensitive C-reactive protein and a composite 10-year cardiovascular risk between the three groups at both 3 and 6 months. Serum uric acid marginally increased by 1.22% in the Soy group and decreased by 4.28% and 4.82% in the Iso and placebo groups at 3 months (P = 0.087), but no difference was observed at 6 months (P = 0.264). Conclusion Soy protein with isoflavones or isoflavones alone at the provided dosage showed no significantly beneficial effects on measured cardiovascular risk factors in postmenopausal Chinese women with early hyperglycaemia.

Liu S., Wang D., Zhang J., Zhang D., Gong M., Wang C., Wei N., Liu W., Wang Y., Zhao C., Cui Y., Hu D.

A previous study has shown that CTN (Citrinin) inhibits mouse testosterone production. In this study, the mechanism by which testosterone production is inhibited by CTN in rat Leydig cells was investigated, and the morphological evidence of apoptosis, including nuclei fragmentation and phosphatidylserine (PS) exposure on cell surfaces, was clearly observed 36h after CTN exposure. The results showed that citrinin at 50 and 100μM significantly suppressed testosterone secretion by human chorionic gonadotropin (hCG) at 10IU/ml. Western blotting results showed that CTN induced formation of processed p53, caspase-9, and caspase-3 proteins in a dose-dependent manner; CTN also induced a dose-dependent increase in caspase-3 catalytic activity. Western blot assays also showed that CTN decreased expression of three key enzymes (P450scc, 3β-HSD-1, and StAR) of testosterone production. Taken together, these results suggested that CTN reduced testosterone secretion by inducing apoptosis in rat Leydig cells, a mechanism that might account for CTN stimulation of p53 expression followed by activation of multiple caspases.

Yokonishi T., Sato T., Katagiri K., Ogawa T.

Research on in vitro spermatogenesis has a long history and remained to be an unaccomplished task until very recently. In 2010, we succeeded in producing murine sperm from primitive spermatogonia using an organ culture method. The fertility of the sperm or haploid spermatids was demonstrated by microinsemination. This organ culture technique uses the classical air–liquid interphase method and is based on conditions extensively examined by Steinbergers in 1960s. Among adaptations in the new culture system, application of serum-free media was the most important. The system is very simple and easy to follow.

Opalka M., Kaminska B., Leska A., Dusza L.

Phytoestrogens (PE) are plant-derived compounds that have an estrogen-like activity and they can influence male and female reproduction. The possible mechanisms of PE action may be including: the binding to estrogen receptors (ER) and the interaction with the key steroidogenic enzymes. The aim of this study was to investigate if PE has effect on steroidogenesis of gander testicular cells by above-described pathways. The Leydig cells were isolated from testes of White Kołuda ganders at the peak of their reproductive activity (March). These Leydig cells (1 × 10(5)per mL) were pre-incubated with the ER inhibitor - ICI 182, 780 (100 nM) for 3 h and then these cells were incubated with PE (5 and 50 μM): genistein, daidzein, equol and coumestrol during next 20 h or untreated control and the Leydig cells that were previously treated (20 h) with genistein (5 and 50 μM) were incubated for next 6 h with steroid intermediates (20 μM) as testosterone (T) precursors: hydroxycholesterol, pregnenolone, progesterone and androstenedione. Concentrations of T in the samples of incubation medium were measured using radioimmunoassay. Genistein, daidzein, and equol (5 and 50 μM) decreased (P < 0.05) T secretion by incubated gander Leydig cells and ICI 182, 780 did not eliminate the inhibitory effect of these PE. After genistein (50 μM) treatment, basal and stimulated with 22R-hydroxycholesterol, pregnenolone, progesterone and androstenedione, T production by testicular cells was decreased (P < 0.05). In contrast, genistein at lower dose (5 μM) did not affect the stimulatory effects of testosterone precursors. In conclusion, the inhibition of testosterone secretion by the phytoestrogens in gander Leydig cells did not depend on estrogen receptors. The suppression of steroidogenesis in these cells may be in part conducted by interaction of phytoestrogens with key steroidogenic enzymes. However, further studies are required to elucidate the phytoestrogen mechanism of action in gander testicular cells.

Pfaehler A., Nanjappa M.K., Coleman E.S., Mansour M., Wanders D., Plaisance E.P., Judd R.L., Akingbemi B.T.

Testicular Leydig cells are the predominant source of the male sex steroid hormone testosterone (T), which is required to maintain male fertility. There is now growing evidence that environmental stressors, including chemicals present in food, air and water, may affect energy balance. A relationship between energy balance and reproductive capacity has been proposed for a long time. In the present study, developmental exposures of male rats to soy isoflavones in the maternal diet from gestational day 12 to day 21 post-partum enhanced adiponectin expression in adipose tissue and increased serum adiponectin concentrations in adulthood. However, exposure to soy isoflavones caused a decrease in T production and expression of adiponectin and its receptor (adipoR2) in Leydig cells. In separate experiments, incubation of Leydig cells with recombinant adiponectin in the absence of isoflavones caused a decrease in T biosynthesis associated with diminished expression of the cholesterol transporter steroidogenic acute regulatory protein (StAR). Thus, chemical-induced alterations in serum adiponectin concentrations have implication for steroid hormone secretion. The results also imply that changes in adipose tissue metabolism occasioned by exposure to dietary estrogens, and perhaps other estrogenic agents, possibly contribute to deficiencies in reproductive capacity attributed to these compounds.

Ye L., Su Z., Ge R.

Martin L.J., Touaibia M.

Androgen production primarily occurs in Leydig cells located in the interstitial compartment of the testis. In aging males, testosterone is crucial for maintaining muscle mass and strength, bone density, sexual function, metabolic health, energy levels, cognitive function, as well as overall well-being. As men age, testosterone production by Leydig cells of the testes begins to decline at a rate of approximately 1% per year starting from their 30s. This review highlights recent findings concerning the use of natural polyphenolics compounds, such as flavonoids, resveratrol, and phenolic acids, to enhance testosterone production, thereby preventing age-related degenerative conditions associated with testosterone insufficiency. Interestingly, most of the natural polyphenolic antioxidants having beneficial effects on testosterone production tend to enhance the expression of the steroidogenic acute regulatory protein (Star) gene in Leydig cells. The STAR protein facilitates the entry of the steroid precursor cholesterol inside mitochondria, a rate-limiting step for androgen biosynthesis. Natural polyphenolic compounds can also improve the activities of steroidogenic enzymes, hypothalamus-pituitary gland axis signaling, and testosterone bioavailability. Thus, many polyphenolic compounds such as luteolin, quercetin, resveratrol, ferulic acid phenethyl ester or gigantol may be promising in delaying the initiation of late-onset hypogonadism accompanying aging in males.

Caceres S., Crespo B., Alonso-Diez A., de Andrés P.J., Millan P., Silván G., Illera M.J., Illera J.C.

The consumption of isoflavones is gaining popularity worldwide due to their beneficial effects on health. However, isoflavones are considered to be endocrine disruptors and cause deleterious effects on hormone-sensitive organs, especially in males. Therefore, this study aimed to determine if a continuous and prolonged exposure to isoflavones in adult males altered the endocrine axis effect of testicular function. For this purpose, seventy-five adult male rats were administered with low and high mixtures of isoflavones (genistein and daidzein) for 5 months. The determination of steroid hormones (progesterone, androstenedione, dehydroepiandrosterone, testosterone, dihydrotestosterone, 17β-estradiol, and estrone sulphate) was carried out in serum and testicular homogenate samples. Sperm quality parameters and testicular histology were also determined. The results revealed that low and high doses of isoflavones promote a hormonal imbalance in androgen and estrogen production, resulting in a decrease in circulating and testicular androgen levels and an increase in estrogen levels. These results are associated with a reduction in the sperm quality parameters and a reduction in the testicular weight, both in the diameter of the seminiferous tubules and the height of the germinal epithelium. Altogether, these results suggest that a continuous exposure to isoflavones in adult male rats causes a hormonal imbalance in the testes that disrupts the endocrine axis, causing defects in testicular function.

Hu X., Li X., Deng P., Zhang Y., Liu R., Cai D., Xu Q., Jiang X., Sun J., Bai W.

Androgen is a kind of steroid hormone that plays a vital role in reproductive system and homeostasis of the body. Disrupted androgen balance serves as the causal contributor to a series of physiological disorders and even diseases. Flavonoids, as an extremely frequent family of natural polyphenols, exist widely in plants and foods and have received great attention when considering their inevitable consumption and estrogen-like effects. Mounting evidence illustrates that flavonoids have a propensity to interfere with androgen synthesis and metabolism, and also have a designated improvement effect on androgen disorders. Therefore, flavonoids were divided into six subclasses based on the structural feature in this paper, and the literature about their effects on androgens published in the past ten years was summarized. It could be concluded that flavonoids have the potential to regulate androgen levels and biological effects, mainly by interfering with the hypothalamic-pituitary-gonadal axis, androgen synthesis and metabolism, androgen binding with its receptors and membrane receptors, and antioxidant effects. The faced challenges about androgen regulation by flavonoids masterly include target mechanism exploration, individual heterogeneity, food matrixes interaction, and lack of clinical study. This review also provides a scientific basis for nutritional intervention using flavonoids to improve androgen disorder symptoms.

He H., Li J., Xie Y., Li Z., Shi H., Lu C.D.

Efficacy of soy isoflavones to promote semen quality by improving antioxidant parameters in Xinong Saanen goats was explored. Soy isoflavones (SI), regulator of steroid hormone synthesis and antiox...

Miyasaka K., Takeda S., Nakamura S., Matsuda H., Shimoda H.

Moriche palm is consumed as both a fresh fruit and processed food in Peru and Brazil. Although its fruit contains phytoestrogens, the active compounds have not yet been identified. Therefore, we purified moriche palm extract (MPE) and identified compounds exhibiting estrogenic and antiandrogenic activities. Estrogenic activity was assessed by the estrogen-dependent growth of MCF-7 cells and increases in uterine weights in mice. Antiandrogenic activity was evaluated by 5α-reductase inhibitory activity and prostate-specific antigen (PSA) expression in LNCaP cells. In vivo antiestrogenic activity was also assessed based on testosterone-induced prostate growth in castrated mice. Four methoxyflavans were isolated from MPE and all, except for 7,4'-dihydroxy-5-methoxyflavan, promoted MCF-7 cell growth, indicating estrogenic activity. Uterine and ovary weights increased in mice orally administered MPE (400 mg/kg) for 2 weeks. Regarding antiandrogenic activity, among the four methoxyflavans isolated, 6,7,4'-trihydroxy-5-methoxyflavan (1 µg/ml) suppressed the mRNA and protein expression of PSA in LNCaP cells. Furthermore, prostate growth was suppressed in mice orally administered MPE (200 mg/kg) for 2 weeks. All methoxyflavans inhibited 5α-reductase activity with IC50 less than 10 µg/ml. Collectively, the present results demonstrated that orally administered MPE exhibited estrogenic and antiandrogenic activities. Methoxyflavans, particularly 6,7,4'-trihydroxy-5-methoxyflavan, appear to be the active compounds for these activities. PRACTICAL APPLICATIONS: The fruit of Mauritia flexuosa (moriche palm) has been used for beverages and processed foods. Although it is said to contain phytoestrogens, the active compounds have not yet been identified. In this study, we isolated and identified methoxyflavans exhibiting estrogenic and antiandrogenic activities. Among them, 6,7,4'-trihydroxy-5-methoxyflavan appeared to be the most effective compounds for these activities.

Martin L.J., Touaibia M.

Androgen production, being important for male fertility, is mainly accomplished by the Leydig cells from the interstitial compartment of the testis. Testosterone plays a critical role in testis development, normal masculinization, and the maintenance of spermatogenesis. Within seminiferous tubules, appropriate Sertoli cell function is highly dependent on testicular androgen levels and is essential to initiate and maintain spermatogenesis. During aging, testosterone production by the testicular Leydig cells declines from the 30s in humans at a rate of 1% per year. This review outlines the recent findings regarding the use of flavonoids and isoflavonoids to improve testosterone production, contributing to normal spermatogenesis and preventing age-related degenerative diseases associated with testosterone deficiency. With the cumulation of information on the actions of different flavonoids and isoflavonoids on steroidogenesis in Leydig cells, we can now draw conclusions regarding the structure-activity relationship on androgen production. Indeed, flavonoids having a 5,7-dihydroxychromen-4-one backbone tend to increase the expression of the steroidogenic acute regulatory protein (StAR), being critical for the entry of cholesterol into the mitochondria, leading to increased testosterone production from testis Leydig cells. Therefore, flavonoids and isoflavonoids such as chrysin, apigenin, luteolin, quercetin, and daidzein may be effective in delaying the initiation of late-onset hypogonadism associated with aging in males.

Hu C., Wong W., Wu R., Lai W.

Soybeans and their food products exist in the market in various forms, ranging from crude oils and bean meals to nutritious products (e.g. soy milk powers). With the availability of technologies for mass production of soy products and for enrichment of soy components (e.g. phospholipids, saponins, isoflavones, oligosaccharides and edible fiber), the nutritional values of soy products have been enhanced remarkably, offering the potential for functional food development. Among different bioactive components in soybeans, one important component is isoflavones, which have been widely exploited for health implications. While there are studies supporting the health benefits of isoflavones, concerns on adverse effects have been raised in the literature. The objective of this article is to review the recent understanding of the biological activities, adverse effects, and use of isoflavones in functional food development.

Ham J., Lim W., Park S., Bae H., You S., Song G.

Propyl gallate (propyl 3,4,5-trihydroxybenzoate, PG) is a phenolic antioxidant that has been used for oil-containing foods to prevent acidification. Owing to its antioxidant properties, PG has been applied to various fields and active research is currently underway to prove PG as an anticancer agent. However, there are still concerns about PG as a possible reproductive toxicant. Therefore, we determined whether PG induced male infertility. Our results indicated that PG induced testicular dysfunction in both Leydig and Sertoli cells via suppression of cell viability and steroidogenesis. These normal testis functions were destroyed by PG-induced mitochondrial dysfunction and calcium homeostasis dysregulation. In addition, PG disrupted the expression of several genes associated with the testis function and induced endoplasmic reticulum stress. Furthermore, we verified PG-induced mRNA expression changes in steroidogenesis enzymes and hormone receptors in vitro and in vivo. From the results of the qPCR analysis, we further confirmed the PG-mediated reduction in the mRNA expression of genes related to testis functions by in situ hybridization. Finally, we demonstrated that PG induced testicular toxicity via the disruption of mitochondrial or ER function and the inhibition of testicular development-related genes in mice.

Sivoňov� M., Kapl�n P., Tatarkov� Z., Lichardusov� L., Dušenka R., Jurečekov� J.

Androgens and androgen receptor (AR) play a critical role not only in normal prostate development, but also in prostate cancer. For that reason, androgen deprivation therapy (ADT) is the primary treatment for prostate cancer. However, the majority of patients develop castration-resistant prostate cancer, which eventually leads to mortality. Novel therapeutic approaches, including dietary changes, have been explored. Soy isoflavones have become a focus of interest because of their positive health benefits on numerous diseases, particularly hormone-related cancers, including prostate and breast cancers. An important strategy for the prevention and/or treatment of prostate cancer might thus be the action of soy isoflavones on the AR signaling pathway. The current review article provides a detailed overview of the anticancer potential of soy isoflavones (genistein, daidzein and glycitein), as mediated by their effect on AR.

Zheng W., Liu T., Sun R., Yang L., An R., Xue Y.

Choriocarcinoma is a malignant gestational trophoblastic disease and relapse or drug resistance occurs in ~25% of gestational trophoblastic tumors. Cell apoptosis serves a role in the progression from hydatidiform mole to persistent gestational trophoblastic disease. It has been demonstrated that daidzein [7‑hydroxy‑3‑(4‑hydroxyphenyl)‑4H‑chromen‑4‑one] may induce apoptosis in a number of cancer types via the mitochondrial apoptotic pathway by altering the B‑cell lymphoma (Bcl)‑2/Bcl‑2 associated X, apoptosis regulator (Bax) ratio, and activating the caspase cascade. Daidzein also serves a role in regulation of production of human chorionic gonadotropin in trophoblast cells and inhibition of cell proliferation. However, few reports have been published regarding the effect of daidzein on apoptosis in choriocarcinoma. Therefore, in the present study, JAR and JEG‑3 human gestational choriocarcinoma cells were used to investigate the effect of daidzein on apoptosis of choriocarcinoma cells. Treatment with daidzein for 48 h reduced cell viability in a dose‑dependent manner. The percentages of early and late apoptotic cells also increased following treatment with daidzein in a dose‑dependent manner, with the number of late apoptotic cells increasing more prominently. Furthermore, treatment with daidzein led to apoptosis‑associated alterations in nuclear morphology of JAR and JEG-3 cells. Expression levels of cleaved poly(ADP‑ribose) polymerase, cleaved caspase‑3 and cleaved caspase‑9 increased following treatment with daidzein, whereas the Bcl‑2/Bax ratio decreased in a dose‑dependent manner. In conclusion, the results of the present study demonstrate that daidzein may induce apoptosis of choriocarcinoma cells in a dose‑dependent manner via the mitochondrial apoptotic pathway.