The Influence of Soy Isoflavones and Soy Isoflavones with Inulin on Kidney Morphology, Fatty Acids, and Associated Parameters in Rats with and without Induced Diabetes Type 2

Diabetes mellitus resulting from hyperglycemia stands as the primary cause of diabetic kidney disease. Emerging evidence suggests that plasma concentrations of soy isoflavones, substances with well-established antidiabetic properties, rise following supplemental inulin administration. The investigation encompassed 36 male Sprague-Dawley (SD) rats segregated into two cohorts: non-diabetic and diabetic, induced with type 2 diabetes (high-fat diet + two intraperitoneal streptozotocin injections). Each cohort was further divided into three subgroups (n = 6): control, isoflavone-treated, and isoflavone plus inulin-treated rats. Tail blood glucose and ketone levels were gauged. Upon termination, blood samples were drawn directly from the heart for urea, creatinine, and HbA1c/HbF analyses. One kidney per rat underwent histological (H-E) and immunohistochemical assessments (anti-AQP1, anti-AQP2, anti-AVPR2, anti-SLC22A2, anti-ACC-alpha, anti-SREBP-1). The remaining kidney underwent fatty acid methyl ester analysis. Results unveiled notable alterations in water intake, body and kidney mass, kidney morphology, fatty acids, AQP2, AVPR2, AcetylCoA, SREBP-1, blood urea, creatinine, and glucose levels in control rats with induced type 2 diabetes. Isoflavone supplementation exhibited favorable effects on plasma urea, plasma urea/creatinine ratio, glycemia, water intake, and kidney mass, morphology, and function in type 2 diabetic rats. Additional inulin supplementation frequently modulated the action of soy isoflavones.

A Gnotobiotic Mouse Model with Divergent Equol-Producing Phenotypes: Potential for Determining Microbial-Driven Health Impacts of Soy Isoflavone Daidzein

The implications of soy consumption on human health have been a subject of debate, largely due to the mixed evidence regarding its benefits and potential risks. The variability in responses to soy has been partly attributed to differences in the metabolism of soy isoflavones, compounds with structural similarities to estrogen. Approximately one-third of humans possess gut bacteria capable of converting soy isoflavone daidzein into equol, a metabolite produced exclusively by gut microbiota with significant estrogenic potency. In contrast, lab-raised rodents are efficient equol producers, except for those raised germ-free. This discrepancy raises concerns about the applicability of traditional rodent models to humans. Herein, we designed a gnotobiotic mouse model to differentiate between equol producers and non-producers by introducing synthetic bacterial communities with and without the equol-producing capacity into female and male germ-free mice. These gnotobiotic mice display equol-producing phenotypes consistent with the capacity of the gut microbiota received. Our findings confirm the model's efficacy in mimicking human equol production capacity, offering a promising tool for future studies to explore the relationship between endogenous equol production and health outcomes like cardiometabolic health and fertility. This approach aims to refine dietary guidelines by considering individual microbiome differences.

Dietary Supplementation of Myo-Inositol, Cocoa Polyphenols, and Soy Isoflavones Improves Vasomotor Symptoms and Metabolic Profile in Menopausal Women with Metabolic Syndrome: A Retrospective Clinical Study

Background and Objectives: Hormonal changes physiologically occurring in menopausal women may increase the risk of developing metabolic and vasomotor disturbances, which contribute to increase the risk of developing other concomitant pathologies, such as metabolic syndrome (MetS). Materials and Methods: Retrospective data from 200 menopausal women with MetS and vasomotor symptoms taking one sachet per day of the dietary supplement INOFOLIC® NRT (Farmares srl, Rome, Italy) were collected. Each sachet consisted of myo-Inositol (2000 mg), cocoa polyphenols (30 mg), and soy isoflavones (80 mg, of which 50 mg is genistin). Patients recorded their symptoms through a medical questionnaire at the beginning of the administration (T0) and after 6 months (T1). Results: We observed an improvement in both the frequency and the severity of hot flushes: increased percentage of 2-3 hot flushes (28 at T0 vs. 65% at T1, p value < 0.001) and decreased percentage of 4-9 hot flushes (54% at T0 vs. 18% at T1, p value < 0.001). Moreover, symptoms of depression improved after supplementation (87% at T0 vs. 56% at T1 of patients reported moderate depression symptoms, p value < 0.001). Regarding metabolic profile, women improved body mass index and waist circumference with a reduction in the percentage of overweight and obesity women (88% at T0 vs. 51% at T1, p value = 0.01; 14% at T0 vs. 9% at T1, p value = 0.04). In addition, the number of women suffering from non-insulin dependent diabetes reduced (26% at T0 vs. 16% at T1, p value = 0.04). Conclusions: These data corroborate previously observed beneficial effects of the oral administration of myo-Inositol, cocoa polyphenols, and soy isoflavones against menopausal symptoms in the study population. Considering the promising results of the present study, further prospective controlled clinical trials are needed to deeply understand and support the efficacy of these natural compounds for the management of menopausal symptoms.

In ovo injection of soy isoflavones on hatching performance and intestinal development of newly hatched chicks

This study aimed to evaluate the effects of in ovo injection of soy isoflavones (ISF) on hatchability, body weight, antioxidant status and intestinal development of newly hatched broiler chicks. One hundred and eighty fertile eggs were divided as follows: the control group, 3 mg/egg ISF (low dose) and 6 mg/egg ISF (high dose) on the 18th day of incubation. The results demonstrated that in ovo inclusion of 6 mg of ISF significantly increased hatchability and hatch weight. Both doses of ISF inclusion elevated the serum glutathione peroxidase and slightly decreased malondialdehyde compared to the control group. The high dose of ISF brings higher villus height and a higher villus/crypt ratio in chicks. Moreover, the mRNA levels of tumour necrosis factor- α and interferon-gamma in the spleen were significantly decreased. The ISF treatments showed an improvement in intestinal enzyme expression levels of sucrose isomaltase and mucin 2  as well as tight junction protein (TJ) mRNA expression of claudin-1 at high doses of ISF (p < 0.05) when compared with the other groups. Furthermore, the mRNA level of IGF-1 was increased in the high doses of ISF compared to the control. Overall, these findings indicate that in ovo administration of ISF on the 18th day of incubation enhances hatchability, antioxidant status and intestinal morphometrics in hatched chicks and modulates the expression of proinflammatory cytokines, TJs and insulin-like growth factor. In addition, the sustainability of antioxidants and other positive effects of ISF may increase chick viability and growth performance.

The improving effect of soybean isoflavones on ovarian function in older laying hens

Emerging evidence suggests an association between estrogen levels and reduced egg-laying performance as the layer became old. Since soy isoflavones (SF) have estrogen-mimic effects, whether it can enhance production performance and ovarian function of older layers is still not known. A total of 160 Lohmann pink layers (66-wk-old) were used in a 2 × 2 factorial design, which included 2 egg-laying levels [low (76.89 ± 1.65%; LOW) and normal (84.96 ± 1.01%; NOR)] and 2 different dietary groups [0 mg/kg SF, 20 mg/kg SF] were used. The results showed the NOR group had higher egg-laying rate, egg mass, and feed efficiency during the all phases (P(laying) < 0.05). The unqualified egg rate was lower in NOR group (9-12 wk, 1-12 wk) (P(laying) < 0.05). Dietary supplementation with SF increased the egg-laying rate and feed efficiency (5-8 wk, 9-12 wk, 1-12 wk), increased egg mass (9-12 wk, 1-12 wk) (P(SF) < 0.05). The NOR layers presented higher eggshell quality (redness, yellowness, brightness, eggshell ratio) at 12 wk (P(laying) < 0.05). Eggshell quality was found to be improved by SF (eggshell strength and eggshell thickness), egg albumen quality (higher albumen height and Haugh unit) at 12 wk (P(SF) < 0.05). Supplementing with SF led to an increase in eggshell strength in LOW group (P(laying*SF) < 0.05). The higher serum lever of glucose (GLU) and lower serum lever of follicle stimulating hormone (FSH) were in NOR group (P(laying) < 0.05). Supplementing SF in diets increased serum of estradiol (E2) and insulin-like growth factors-1 (IGF-1), decreased serum of FSH (P(SF) < 0.05). The NOR layers presented lower estrogen receptor α (ERα), estrogen receptor β (ERβ), B lymphoma 2 associated X protein (Bax), cytochrome c (Cytc), interleukin 6 (IL-6), caspase3, caspase9, IKKα, P50, and P65 expression in the ovary (P(laying) < 0.05). Dietary SF supplementation decreased the anti-Müllerian hormone receptor (AMHR), Bax, caspase3, caspase9, Cytc, IL-6, IKKα, P50, P65 expression in the ovary (P(SF) < 0.05). These findings indicated that layers with NOR group had higher production performance, egg quality, and ovarian function, while dietary supplementation with SF improved production performance and ovarian function by reducing inflammation and apoptosis-related genes expression in ovary.

Safety Assessment and Hepatic-Renal Protection of Cajanus cajan (L.) Millsp. Root and Its Soy Isoflavone Contents

Cajanus cajan (L.) Millsp., also known as pigeon pea, has roots that have exhibited much pharmacological potential. The present study was conducted to assess the safe dose of the ethanolic extract of C. cajan roots (EECR95) and to analyze the main soy isoflavones contents. In vitro, we investigated the mutagenicity and cytotoxic effect of EECR95 on Salmonella typhimurium-TA98 and TA100 (by Ames tests) and RAW 264.7, L-929, and HGF-1 cell lines (by MTT tests) for 24 h of incubation. We found no mutagenic or cytotoxic effects of EECR95. After administration of 0.2 or 1.0 g/kg bw of EECR95 to both male and female Wistar rats for 90 days, there were no significant adverse effects on the behaviors (body weight, water intake, and food intake), organ/tissue weights, or immunohistochemical staining, and the urine and hematological examinations of the rats were within normal ranges. EECR95 potentially decreases renal function markers in serum (serum uric acid, BUN, CRE, and GLU) or liver function markers (cholesterol, triglyceride, and glutamic-pyruvate-transaminase (GPT)). We also found that EECR95 contained five soy isoflavones (genistein, biochanin A, daidzein, genistin, and cajanol), which may be related to its hepatorenal protection. Based on the high dose (1.0 g/kg bw) of EECR95, a safe daily intake of EECR95 for human adults is estimated to be 972 mg/60 kg person/day.

The Role of Choline, Soy Isoflavones, and Probiotics as Adjuvant Treatments in the Prevention and Management of NAFLD in Postmenopausal Women

Nonalcoholic fatty liver disease (NAFLD) is a prevalent condition among postmenopausal women that can lead to severe liver dysfunction and increased mortality. In recent years, research has focused on identifying potential lifestyle dietary interventions that may prevent or treat NAFLD in this population. Due to the complex and multifactorial nature of NAFLD in postmenopausal women, the disease can present as different subtypes, with varying levels of clinical presentation and variable treatment responses. By recognizing the significant heterogeneity of NAFLD in postmenopausal women, it may be possible to identify specific subsets of individuals who may benefit from targeted nutritional interventions. The purpose of this review was to examine the current evidence supporting the role of three specific nutritional factors-choline, soy isoflavones, and probiotics-as potential nutritional adjuvants in the prevention and treatment of NAFLD in postmenopausal women. There is promising evidence supporting the potential benefits of these nutritional factors for NAFLD prevention and treatment, particularly in postmenopausal women, and further research is warranted to confirm their effectiveness in alleviating hepatic steatosis in this population.

Effects of Phytochemicals from Fermented Food Sources in Alzheimer's Disease In Vivo Experimental Models: A Systematic Review

The socioeconomic burden of Alzheimer's Disease (AD) stems from its characteristic multifactorial etiology and, implicitly, the difficulties associated with its treatment. With the increase in life expectancy and health awareness, nutraceuticals and functional foods are filling in the gaps left by the limitation of classical medical treatment in chronic conditions associated with lifestyle factors, such as neurological disorders. Processes, such as fermentation that enhance food phytochemical content are garnering increased attention due to their functional and health-related properties. This systematic review aims to provide an overview of the evidence of phytochemicals from fermented food sources inducing therapeutic outcomes and cognitive benefits from in vivo experimental models of Alzheimer's Disease. The present systematic review was conducted in accordance with PRISMA guidelines. Searches were performed in the following databases: MEDLINE, Embase, Cochrane, Scopus, Google Scholar, and Science Citation Index Expanded (Web of Science) by two independent reviewers. Titles and abstracts yielded by the search were screened for eligibility against the inclusion criteria. The search strategy yielded 1899 titles, encompassing studies from 1948 to 2022. After the removal of duplicates, and screening of titles, abstracts, and full texts, thirty three studies obtained from the original search strategy and seven studies from references satisfied the inclusion criteria and were included in the present systematic review. Several studies have emphasized the potential of fermentation to yield small-molecule phytochemicals that are not present in raw products. When these phytochemicals are combined, their collective strength has demonstrated the ability to exceed the antioxidant, anti-inflammatory, and neuroprotective benefits of individual phytochemicals when given in their pure form. Among the various fermented foods that have been studied, soy isoflavones obtained through fermentation have shown the most substantial evidence of altering phytochemical content and improving outcomes in animal models of AD. While promising in initial results, other fermented foods and traditional medicines require more detailed research in order to establish their effectiveness and proper utilization. As is, many of the experimental designs lacked phytochemical analysis of the used fermented product or comparison with the non-fermented counterpart. This, coupled with proper reporting in animal studies, will significantly raise the quality of performed studies as well as the weight of obtained results.

Validation of ELISAs for Isoflavones and Enterolactone for Phytoestrogen Intake Assessment in the French Population

Phytoestrogens are dietary compounds with low estrogenic activity. The two main categories in the French diet are isoflavones from pulses and enterolignans metabolized by the gut flora from various lignans found in fruits, vegetables, grains, and beverages. Isoflavones and lignans have different effects on human physiology and can antagonize each other. Comprehensive lists of phytoestrogen sources were constructed based on measurements and literature data. The 24 h and 48 h dietary recalls were proposed to the volunteers of the ISOLED cohort (NCT03421184). Urine and plasma samples from these volunteers were assayed for genistein, daidzein, equol, and enterolactone. A dietary score was constructed considering the pharmacokinetic characteristics of these compounds. Correlation analyses were applied to fluid concentrations associated with dietary scores. Pearson correlations reached 0.921 (p < 0.001) for urine_IF, 0.900 (p < 0.001) for plasma_IF, 0.764 (p < 0.001) for urine_ENL, and 0.723 (p < 0.001) for plasma_ENL. ELISAs associated with careful intake assessments proved to be good tools for phytoestrogens' exposure estimation.

Health Effects of Soy Isoflavones and Green Tea Catechins on Cancer and Cardiovascular Diseases Based on Urinary Biomarker Levels

Plant polyphenols have various health effects. Genistein, which is abundant in soybeans, and epigallocatechin-3-gallate, which is abundant in green tea, are major flavonoids, a subclass group of polyphenols. Several epidemiological studies have shown that these flavonoids have beneficial effects against cancer and cardiovascular diseases. However, other studies did not show such effects. Several confounding factors, including recall bias, are related to these inconsistent findings, and the determination of metabolites in the urine may be useful in reducing the number of confounding factors. Equipment, which can be used by research participants to collect samples from a portion of voided urine within 24 h without the help of medical workers, has been developed for epidemiological investigations. Previous studies, in which flavonoid metabolites in these urine samples were measured, revealed that soy intake was correlated with a reduced risk of certain types of cancer and cardiovascular diseases worldwide. Although soybeans and green tea consumption may have protective effects against cancer and cardiovascular diseases, further clinical studies that consider different confounding factors are required to provide evidence for the actual impact of dietary flavonoids on human diseases, including cancer and cardiovascular diseases. One possible mechanism involved is discussed in relation to the downregulation of reactive oxygen species and the upregulation of 5'-adenosine monophosphate-activated protein kinase elicited by these flavonoids.

Can soy isoflavones in combination with soy protein change serum concentration of adiponectin and resistin? A systematic review and meta-analysis on randomized clinical trials

Some studies proposed the anti-inflammatory effect of soy protein and soy isoflavones by changing the serum adiponectin and resistin levels. The purpose of this research was to determine the impact of soy isoflavones and soy protein on blood adiponectin and resistin levels in adults. Scopus, PubMed, Cochrane Library, ISI Web of Science, and ClinicalTrials.gov databases were searched until April 2022. The effect size was computed by the mean changes from the beginning for intervention and comparison groups and their standard deviation. In the case of significant heterogeneity, DerSimonian and Laird random-effects model was used. Six and five clinical trials were selected for the systematic review and meta-analysis, respectively. The overall estimate indicated that soy isoflavones in combination with soy protein did not significantly change serum adiponectin level (weighted mean differences (WMD) = 0.36 μg/ml; 95% confidence interval (CI): -0.26, 0.99; p = .25), but significantly increased serum resistin level (WMD = 0.64 ng/ml, 95% CI: 0.25, 1.04; p = .001). In combination with soy protein, soy isoflavones nonsignificantly increased serum adiponectin levels, but significantly increased resistin levels. New intervention studies with a high dose of soy isoflavones and soy protein in different parts of the world and an updated meta-analysis are needed to confirm the results of our study.

Development of an Assay for Soy Isoflavones in Women's Hair

Soy isoflavones, at adequate dosages, have estrogenic and anti-thyroidal effects in animals and humans, which can either be beneficial or adverse, depending on the consumer’s physiological status. Hence, this study presents an assay of soy isoflavones in hair, aiming to give new information about a person’s exposure to isoflavones, when health issues related to estrogenic or thyroidal effects are observed. Aqueous or organic extraction procedures following acidic, basic, or enzymatic digestions were tested on 60 hair samples (from volunteers) from a hairdresser, and a clinical trial 2017T2-29. The acidic digestion method was the most efficient regarding isoflavones. A specific inquiry was developed to assess the dietary habits of French consumers based on the analysis of 12,707 food labels from France. It was used to check for the reliability of the new assay method. A score for the consumer exposures to isoflavones was built considering, among other parameters, soy-based diets and foodstuff containing soy as an ingredient, i.e., “hidden-soy”. The correlation between this score and isoflavone measurements in hair reached 0.947; p < 0.001. Therefore, providing that relevant data are considered to assess isoflavone exposure, hair that smoothens daily isoflavone intake variations, is a relevant tissue to assess human isoflavone exposure for subsequent health analyses.

Influences of Dietary Vitamin E, Selenium-Enriched Yeast, and Soy Isoflavone Supplementation on Growth Performance, Antioxidant Capacity, Carcass Traits, Meat Quality and Gut Microbiota in Finishing Pigs

This study investigated the effects of dietary compound antioxidants on growth performance, antioxidant capacity, carcass traits, meat quality, and gut microbiota in finishing pigs. A total of 36 barrows were randomly assigned to 2 treatments with 6 replicates. The pigs were fed with a basal diet (control) or the basal diet supplemented with 200 mg/kg vitamin E, 0.3 mg/kg selenium-enriched yeast, and 20 mg/kg soy isoflavone. Dietary compound antioxidants decreased the average daily feed intake (ADFI) and feed to gain ratio (F/G) at d 14−28 in finishing pigs (p < 0.05). The plasma total protein, urea nitrogen, triglyceride, and malondialdehyde (MDA) concentrations were decreased while the plasma glutathione (GSH) to glutathione oxidized (GSSG) ratio (GSH/GSSG) was increased by compound antioxidants (p < 0.05). Dietary compound antioxidants increased loin area and b* value at 45 min, decreased backfat thickness at last rib, and drip loss at 48 h (p < 0.05). The relative abundance of colonic Peptococcus at the genus level was increased and ileal Turicibacter_sp_H121 abundance at the species level was decreased by dietary compound antioxidants. Spearman analysis showed a significant negative correlation between the relative abundance of colonic Peptococcus and plasma MDA concentration and meat drip loss at 48 h. Collectively, dietary supplementation with compound antioxidants of vitamin E, selenium-enrich yeast, and soy isoflavone could improve feed efficiency and antioxidant capacity, and modify the backfat thickness and meat quality through modulation of the gut microbiota community.

Effects of Soy Isoflavones and Green Tea Extract on Simvastatin Pharmacokinetics and Influence of the SLCO1B1 521T > C Polymorphism

Objectives

Green tea and soy products are extensively consumed by many people and they may influence the activity of drug metabolizing enzymes and drug transporters to result in drug interactions. This study was performed to evaluate the effect of green tea and soy isoflavone extracts on the pharmacokinetics of simvastatin in healthy subjects and to clarify the role of polymorphisms in the SLCO1B1 drug transporter in this effect.

Methods

This was an open-label, three-phase randomized crossover pharmacokinetic study. A single dose of simvastatin 20 mg was taken on three occasions (without herbs, with green tea, and with soy isoflavones) by healthy male Chinese subjects. The green tea and soy isoflavone extracts were given at a dose containing EGCG 800 mg once daily or soy isoflavones about 80 mg once daily for 14 days before simvastatin dosing with at least 4-weeks washout period between phases.

Results

All the 18 subjects completed the study. Intake of soy isoflavones was associated with reduced systemic exposure to simvastatin acid [geometric mean (% coefficient of variation) AUC_0-24h from 16.1 (44.2) h⋅μg/L to 12.1 (54.6) h⋅μg/L, P < 0.05) but not the lactone. Further analysis showed that the interaction between simvastatin and the soy isoflavones only resulted in a significant reduction of AUC in subjects with the SLCO1B1 521TT genotype and not in those with the 521C variant allele. There was no overall effect of the green tea extract on simvastatin pharmacokinetics but the group with the SLCO1B1 521TT genotype showed reduced AUC values for simvastatin acid.

Conclusion

This study showed repeated administration of soy isoflavones reduced the systemic bioavailability of simvastatin in healthy volunteers that was dependent on the SLCO1B1 genotype which suggested that soy isoflavones-simvastatin interaction is impacted by genotype-related function of this liver uptake transporter.

Functional Brain Asymmetry and Menopausal Treatments: Is There a Link?

Background and Objectives: The human brain presents a functional asymmetry for every cognitive function, and it is possible that sexual hormones could have an impact on it. Visual−spatial attention, one of the most lateralized functions and one that is mainly dependent on the right hemisphere, represents a sentinel for functional cerebral asymmetry (FCA). The aim of this study was to evaluate whether menopausal hormone therapy (MHT) or phytoestrogens could modulate FCA in postmenopausal women. Materials and Methods: We enrolled postmenopausal women who were taking MHT or soy isoflavones or receiving no therapy and asked them to perform the line bisection test at study enrollment and after 18 and 36 months. Results: Ninety women completed the follow-up. At zero time, women who had not been subjected to therapy showed a leftward deviation (F = −3.0), whereas, after 36 months, the test results showed a rightward deviation (F = 4.5; p < 0.01). Women taking MHT showed a leftward deviation at the start (F = −3.0) and a persistent leftward deviation after 36 months (F = −4.0; p = 0.08). Conversely, women taking soy isoflavones started with a leftward deviation (F = −3.0) that became rightward (F = 3.0), with a significant difference shown after 36 months (p < 0.01). Conclusions: Our data suggest that hormonal modulation improves the interplay between the two hemispheres and reduces FCA. We propose, therefore, that the functions of the right hemisphere are mainly affected by aging and that this could be one of the reasons why the right hemisphere is more susceptible to the effects of MHT.

A Meta-Analysis of Randomized Controlled Trials of the Effects of Soy Intake on Inflammatory Markers in Postmenopausal Women

BACKGROUND

Elevated concentrations of serum inflammatory cytokines, specifically TNF-α and IL-6, as well as C-reactive protein (CRP), are commonly observed after menopause.

OBJECTIVES

Because soy isoflavones may have some anti-inflammatory potential, the aim of the present systematic review and meta-analysis of randomized controlled trials (RCTs) was to explore whether soy intake affects serum markers of inflammation in postmenopausal women.

METHODS

PubMed, Web of Science, and the Cochrane Library were systematically searched up to August 2020. All RCTs that met the following criteria were included: 1) studies of the effects of soy intake on inflammatory markers; 2) any date of publication; 3) conducted on postmenopausal women; 4) with sufficient quantitative data for meta-analysis. Effect sizes were expressed as weighted mean differences (WMDs) and 95% CIs. A total of 24 RCTs assessing the effects of soy intake on serum concentrations of CRP, TNF-α, and IL-6 were included in the analysis. A random-effects model was used to determine the overall effect.

RESULTS

Soy supplementation significantly reduced CRP by 0.11 mg/L in postmenopausal women (95% CI: -0.22, -0.004 mg/L; P = 0.0414), but did not affect IL-6 or TNF-α. Significant reductions in CRP concentration occurred when natural soy products were given (WMD: -0.23 mg/L; 95% CI: -0.29, -0.17 mg/L; P < 0.001). This is equivalent to a ∼9% reduction in CRP concentration from baseline.

CONCLUSIONS

Although our meta-analysis found evidence that soy products significantly reduce CRP concentrations in postmenopausal women, the mechanisms by which soy foods and their constituents affect inflammatory biomarkers still need to be clarified.This systematic review was registered at www.crd.york.ac.uk/prospero/ as CRD42020179232.

The Impact of Soy Isoflavone Supplementation on the Menopausal Symptoms in Perimenopausal and Postmenopausal Women

Introduction

Approximately one-third of a woman's life is spent in the menopausal phase. The unpleasant menopausal symptoms are unacceptable as a part of routine life. Indications of menopausal hormone therapy (MHT) are for alleviation of vasomotor symptoms, prevention of osteoporosis, and genitourinary symptoms associated with menopause. MHT is associated with an increased risk of breast cancer, cerebrovascular accidents, and coronary heart disease. Soy isoflavones have been extensively used as an alternative treatment in patients who cannot take MHT. The evidence of the efficacy of isoflavones in the literature is equivocal.

Aim

The aim of the study was to evaluate the efficacy of soy isoflavone supplementation on menopausal symptoms in perimenopausal and postmenopausal women and to evaluate the effect on blood pressure (BP) and body mass index (BMI).

Materials and Methods

A questionnaire-based prospective observational study was undertaken involving 39 perimenopausal and 61 postmenopausal women, who were prescribed 40 mg soy isoflavone supplements twice daily for 12 weeks. Menopause Rating Scale questionnaire was given to the patients before starting soy isoflavone therapy and at the end of the treatment; BP and BMI were also noted.

Results

The total score of both the groups was comparable at baseline. Among perimenopausal and postmenopausal women, the highest score was noted in symptoms of somatic domain. At the completion of our study, the total scores improved significantly by 38.6% and 33.3% in perimenopausal and postmenopausal women, respectively. The greatest improvement was seen in somatic subscale (42.5%) and psychological subscale (42.5%) and the least in urogenital subscale (16.1%) for perimenopausal women. For postmenopausal women, the greatest improvement was seen in psychological subscale (40.0%) and the least in urogenital subscale (14.2%).

Conclusion

Soy isoflavone supplementation is beneficial in both perimenopausal and postmenopausal women, more so in perimenopausal women. There is no beneficial effect of soy isoflavone supplementation on lowering systolic BP and BMI.

Well-Balanced Lunch Reduces Risk of Lifestyle-Related Diseases in Middle-Aged Japanese Working Men

Based on the results of a previous WHO-CARDIAC study, this study was designed to test the effect of the daily consumption of a diet rich in potassium with optimal salt content, rich in fish meat and soy isoflavones, corresponding to the ingredients of a traditional Japanese diet. The test meals were a Balanced Lunch (BL) with chicken as the main dish and a Fortified Lunch (FL) with fish and soy as the main dish, which appeared the same. A double-blind, randomized controlled trial was conducted in 64 relatively obese men (47.2 ± 5.5 years old) who consumed the lunch at their work site for 4 weeks. All participants underwent fasting blood sampling, 24-h urine collection, as well as measurements of height, weight, and blood pressure before and after the intervention. Body mass index, blood pressure, and HbA1c were significantly improved and a 3-g reduction of salt intake was proven by 24-h urine collection in both groups. Moreover, HDL cholesterol and the Atherogenic Index (AI) were significantly improved in the FL group. In conclusion, the risks of lifestyle-related diseases in working men were reduced by one meal per day intervention of optimally-salted traditional Japanese diets containing soy and fish nutrients with high vegetable ingredients.

Effects of Soy Isoflavones, Resistant Starch and Antibiotics on Polycystic Ovary Syndrome (PCOS)-Like Features in Letrozole-Treated Rats

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in reproductive-aged women. Recently, various dietary interventions have been used extensively as a novel therapy against PCOS. In the present study, we show that soy isoflavone metabolites and resistant starch, together with gut microbiota modulations, were successful in decreasing the severity of PCOS-like reproductive features while increasing the expression of gut barrier markers and butyric acid in the gut. In the letrozole-induced PCOS model rats, the intake of both 0.05% soy isoflavones and 11% resistant starch, even with letrozole treatment, reduced the severity of menstrual irregularity and polycystic ovaries with a high concentration of soy isoflavones and equol in plasma. Antibiotic cocktail treatment suppressed soy isoflavone metabolism in the gut and showed no considerable effects on reducing the PCOS-like symptoms. The mRNA expression level of occludin significantly increased with soy isoflavone and resistant starch combined treatment. Bacterial genera such as Blautia, Dorea and Clostridium were positively correlated with menstrual irregularity under resistant starch intake. Moreover, the concentration of butyric acid was elevated by resistant starch intake. In conclusion, we propose that both dietary interventions and gut microbiota modulations could be effectively used in reducing the severity of PCOS reproductive features.

Antioxidant Effect of Lactobacillus fermentum CQPC04-Fermented Soy Milk on D-Galactose-Induced Oxidative Aging Mice

The aim of this study is to evaluate the changes in soy isoflavones and peptides in soy milk after lactic acid bacterial fermentation, and explore the positive effects of fermented soy milk on an oxidative aging mouse model induced with D-galactose. We found that free soybean isoflavones and peptides increased after soy milk was fermented by Lactobacillus fermentum CQPC04. The in vivo results indicated that L. fermentum CQPC04-fermented soy milk enhanced the organ index of the liver and spleen, and improved the pathological morphology of the liver, spleen, and skin. L. fermentum CQPC04-fermented soy milk increased the enzymatic activity of glutathione peroxidase (GSH-Px), total superoxide dismutase (T-SOD), and catalase (CAT), increased glutathione (GSH), but decreased the levels of nitric oxide (NO) and malondialdehyde (MDA) in serum, liver, and brain tissues of oxidative aging mice. The above mentioned fermented soy milk also increased the levels of collagen I (Col I), hyaluronic acid (HA), and collagen III (Col III), and decreased the levels of advanced glycation End products (AGEs) and hydrogen peroxide (H₂O₂). The RT-qPCR results showed that L. fermentum CQPC04-fermented soy milk upregulated the mRNA expression of nuclear factor erythroid 2?related factor (Nrf2), heme oxygenase-1 (HMOX1), quinone oxido-reductase 1 (Nqo1), neuronal nitric oxide synthase (NOS1), endothelial nitric oxide synthase (NOS3), Cu/Zn–superoxide dismutase (Cu/Zn-SOD), Mn–superoxide dismutase (Mn-SOD), and CAT, but downregulated the expression of inducible nitric oxide synthase (NOS2) and glutamate cysteine ligase modifier subunit (Gclm) in liver and spleen tissues. Lastly, the fermented soy milk also increased the gene expression of Cu/Zn-SOD, Mn-SOD, CAT, GSH-Px, matrix metalloproteinases 1 (TIMP1), and matrix metalloproteinases 2 (TIMP2), and decreased the expression of matrix metalloproteinase 2 (MMP2) and matrix metalloproteinase 9 (MMP9) in skin tissue. In conclusion, L. fermentum CQPC04-fermented soy milk was able to satisfactorily delay oxidative aging effects, and its mechanism may be related to the increase in free soy isoflavones and peptides.

Exploring the prophylactic role of soy isoflavones against polycystic ovarian syndrome

Soy isoflavones (SI) have strong estrogenic effect in tissues by binding to estrogen receptors and might be beneficial for women with polycystic ovarian syndrome (PCOS) by reduction in testosterone, cholesterol, insulin, weight gain, inflammatory markers, and oxidative stress. The study was planned to examine the effect of various levels of SI on nutrient intake, digestibility, lipid profile, insulin, and reproductive hormones of estradiol valerate (4 mg/rat/IM) PCOS induced rat models. Thirty-six Wistar 45 days old rats weighing 95 ± 5 g were divided into 4 groups, each having 9 rats: C (control: without SF), SF10 (SF 0.10 g/kg BW), SF15 (SF 0.15 g/kg BW), and SF20 (SF 0.20 g/kg BW). SF was given through the oral gavage. Food and water were offered ad libitum, and intake was recorded daily. During last week of trial, collected feces by total collection method and blood samples were used to calculate nutrient digestibility and biochemical analysis, respectively. Estrogen, progesterone, and prolactin were (p < .05) high in rats fed SF diet that was 4% and 30% increase from C, respectively. Insulin, testosterone, FSH, and LH were lowest in rats fed diet SF20. Significant (p < .05) reduction in cholesterol was observed in rats fed SF15 and SF20 as compared to C. Serum HDL was improved (p < .05) in all SIF0.10, SIF0.15, and SIF0.20 in comparison with PC. Serum LDL was significantly reduced to 68.89 ± 4.36 (mg/dl) in SIF0.20 and to 108.20 ± 4.14 (mg/dl) in SIF0.15, whereas insignificant reduction was observed in SIF0.10 as compared to PC. Highly significant reduction was noted in triglycerides level in SIF0.20; however, significant reduction was observed in both SIF0.10 and SIF0.15 as compared to PC after 3 months of treatment with soy isoflavones.

Soy Isoflavones Intake and Obesity in Chinese Adults: A Cross-Sectional Study in Shanghai, China

This study was designed to examine the association of soy isoflavones (SI) intake with different body measurements indicative of obesity in Chinese adults of Shanghai, a population consuming foods rich in SI. This study used baseline data from the Shanghai Gaofeng cohort study. SI intake was measured by using a self-reported food frequency questionnaire (FFQ). A restricted cubic spline (RCS) was performed to examine the possible nonlinear relationship of SI intake with obesity. A logistic regression model was applied to estimate the odds ratios (OR) and 95% confidence interval (CI). Compared with the lowest tertile group of SI intake, the highest tertile group had a lower prevalence of obesity and central obesity. The OR for overall obesity was 0.91 (95% CI: 0.85, 0.98) in the highest versus the lowest SI tertile group; the associations differed by sex and menopausal status. A negative association was also observed between SI intake and central obesity, and a significant modifying effect of sex was found on the association. No significant interactions were observed between SI intake and physical activity (PA) levels. Our results suggest that Chinese adults with higher dietary intake of SI may be less likely to be obese, particularly for postmenopausal women.

Heterologous expression of equol biosynthesis genes from Adlercreutzia equolifaciens

Equol is the isoflavone-derived metabolite with the greatest estrogenic and antioxidant activity. It is produced from daidzein by fastidious and oxygen-susceptible intestinal bacteria, which hinders their use at an industrial scale. Therefore, expressing the equol production machinery into easily-cultivable hosts would expedite the heterologous production of this compound. In this work, four genes (racemase, tdr, ddr and dzr) coding for key enzymes involved in equol production in Adlercreutzia equolifaciens DSM19450^T were synthesized and cloned in a pUC-derived vector (pUC57-equol) that was introduced in Escherichia coli. Recombinant clones of E. coli produced equol in cultures supplemented with daidzein (equol precursor) and dihydrodaidzein (intermediate compound). To check whether equol genes were expressed in Gram-positive bacteria, the pUC57-equol construct was cloned into the low-copy-number vector pIL252, and the new construct (pIL252-pUC57-equol) introduced into model strains of Lacticaseibacillus casei and Lactococcus lactis. L. casei clones carrying pIL252-pUC57-equol produced a small amount of equol from dihydrodaidzein but not from daidzein, while L. lactis recombinant clones produced no equol from either of the substrates. This is the first time that A. equolifaciens equol genes have been cloned and expressed in heterologous hosts. E. coli clones harboring pUC57-equol could be used for biotechnological production of equol.

Effects of Soy Isoflavones on Glycemic Control and Lipid Profile in Patients with Type 2 Diabetes: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

The aim of the report was to investigate the impact of soy protein and isoflavones on glucose homeostasis and lipid profile in type 2 diabetes. The studies used in this report were identified by searching through the MEDLINE and EMBASE databases (up to 2020). Meta-regression and subgroup analyses were performed to explore the influence of covariates on net glycemic control and lipid changes. Weighted mean differences and 95% confidence intervals (CI) were calculated by using random-effect models. Changes in the lipid profile showed statistically significant decreases in total cholesterol and LDL-C concentrations: ‒0.21 mmol/L; 95% CI, ‒0.33 to ‒0.09; p = 0.0008 and ‒0.20 mmol/L; 95% CI, ‒0.28 to ‒0.12; p < 0.0001, respectively, as well as in HDL-C (−0.02 mmol/L; 95% CI, −0.05 to 0.01; p = 0.2008 and triacylglycerols (−0.19 mmol/L; 95% CI, −0.48 to 0.09; p = 0.1884). At the same time, a meta-analysis of the included studies revealed statistically insignificant reduction in fasting glucose, insulin, HbA1c, and HOMA-IR (changes in glucose metabolism) after consumption of soy isoflavones. The observed ability of both extracted isoflavone and soy protein with isoflavones to modulate the lipid profile suggests benefits in preventing cardiovascular events in diabetic subjects. Further multicenter studies based on larger and longer duration studies are necessary to determine their beneficial effect on glucose and lipid metabolism.

Effects of Soy Isoflavones on Biochemical Markers of Bone Metabolism in Postmenopausal Women: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

This systematic review and meta-analysis of randomized controlled trials was performed to more completely assess potential changes in bone turnover marker levels in postmenopausal women during the intake of soy isoflavones. PubMed (Medline) and EMBASE were searched for relevant studies, and their quality was evaluated according to Cochrane criteria. The levels of markers were evaluated in a total of 1114 women who ingested mean daily doses of 98.2 mg (30.9 to 300) of soy isoflavones for 3 to 24 months, in comparison to those of 1081 subjects who used a placebo. Ten, eighteen, eight, and fourteen comparison studies were finally selected for an estimation of the effects on osteocalcin (OC), bone alkaline phosphatase (BAP), pyridinoline (PYD), and deoxypyridinoline (DPD), respectively. A summary of the results of intervention was as follows: 4.16%, 95% CI: -7.72-16.04, p = 0.49 for OC; 5.50%, 95% CI: -3.81-14.82, p = 0.25 for BAP; -12.09%, 95% CI: -25.37-1.20, p = 0.07 for PYD; and -7.48%, 95% CI: -15.37-0.41, p = 0.06 for DPD. The meta-analysis of the included studies revealed some statistically insignificant observations that soy isoflavones intake is associated with a trend in increased levels of OC and BAP, as well as a trend in reduced levels of PYD and DPD. Soy isoflavones may have a beneficial effect on bone formation markers, but this requires extensive multi-center research.

The effect of soy isoflavones and soy isoflavones plus soy protein on serum concentration of tumor necrosis factor-α? A systematic review and meta-analysis of randomized controlled trials

In this study, we summarized the effect of soy isoflavones and soy isoflavones plus soy protein on serum concentration of tumor necrosis factor-alpha (TNF-α) among adult participants. We systematically searched Scopus, ISI Web of Science, Cochrane Library, PubMed, and clinicaltrials.gov for articles published up to May 2020. Effect size was calculated by mean change from baseline of TNF-α concentrations and its standard deviation (SD) for intervention and comparison groups. If the heterogeneity test was statistically significant, DerSimonian and Laird random effects model was used to estimate the summary of the overall effects and its heterogeneity. Nineteen and fourteen randomized clinical trials were included in our systematic review and meta-analysis, respectively. The result of overall effect size indicated a non-significant effect in serum concentration of TNF-α following soy isoflavones intake (WMD = 0.2 pg/ml, 95% CI: -0.13, 0.53; p = .226) and the combination of soy isoflavones and soy protein intake (WMD = 0.02 pg/ml, 95% CI: -0.02, 0.06; p = .286). Subgroup analyses revealed no significant change in circulatory levels of TNF-α following soy isoflavones plus soy protein intake. In conclusion, the present systematic review and meta-analysis found insufficient evidence that soy isoflavones or the combination of soy isoflavones and soy protein significantly reduce serum concentration of TNF-α.

[Effects of resveratrol combined with soy isoflavones on apoptosis induced by oxidative stress in hippocampus of aging model rats]

OBJECTIVE

To investigate the effect of resveratrol(Res) combined with soy isoflavones(SIF) on apoptosisinduced by oxidative stress in hippocampus in aging model rats.

METHODS

Sixty female SD rats were randomly divided into the Sham control group, aging model group, Res treatment group, SIF treatment group, Res combined with SIF treatment group and estrogen replacement therapy group(ERT group). Rats with aging were induced by bilateral ovariectomy combined with intraperitoneal injection of D-galactose. TUNEL and transmission electron microscopy were used to observe apoptosis and ultrastructural changes of mitochondrion in hippocampus, respectively. The activities of superoxide dismutase(SOD), catalase(CAT), glutathione peroxidase(GSH-Px) and content of Malonaldehyde(MDA) were detected in the hippocampal homogenate. The protein expressions of cytochrome C oxidase(COX) Ⅰ, Bcl-2 associated X protein(Bax)、B-cell leukemia/lymphoma 2(Bcl-2) and cytochrome C were detected by Western blot.

RESULTS

Compared with the Sham control group, the number of TUNEL-positive cells and the apoptotic index(AI) in the model group increased. Marked increase of mitochondrial swelling and vacuolation, decrease of mitochondrial integrity were also observed in the model group. Additionally, the levels of SOD, CAT and GSH-Px were decreased and the level of MDA was increased in the model group in the hippocampus, Bax and cytochrome C protein expression increased, and the COX Ⅰ protein expression and the ratio of Bcl-2/Bax decreased(P&lt;0. 05). In compared with the model group, the number of TUNEL-positive cells and AI significantly decreased, mitochondrial integrity improved in all of the treatment groups, the COX Ⅰ protein expression significantly up-regulated, Bax and cytochrome C protein expression down-regulated, and the protein expression ratio of Bcl-2/Bax increased(P&lt;0. 05 or P&lt;0. 01). Compared with the Res alone and SIF alone treatment group, Res combined SIF treatment decreased the AI and Bax, cytochrome C protein expression, moreover, increased the mitochondrial integrity rate, COX Ⅰ and Bcl-2/Bax protein expression ratio(P&lt;0. 05). There was no statistically significant difference in Bcl-2 protein expression among all the groups(P&gt;0. 05).

CONCLUSION

Res and SIF alone and in combination decreased apoptosisinduced by oxidative stress in hippocampus of aging model rats, and beneficial effect in the Res combined SIF treatment group is more significant than that in the alone administration. Improving the antioxidant capacity, increasing the protein expressions of COX Ⅰ andthe ratio of Bcl-2 and Bax, and inhibiting the release of cytochrome C may be the mechanisms by which Res and SIF improve apoptosis in aging rats.

From Proteomics to Personalized Medicine: The Importance of Isoflavone Dose and Estrogen Receptor Status in Breast Cancer Cells

Continuing efforts are directed towards finding alternative breast cancer chemotherapeutics, with improved safety and efficacy profiles. Soy isoflavones represent promising agents but, despite extensive research, limited information exists regarding their impact on the breast cancer cell proteome. The purpose of this study was to compare the proteomic profiles of MCF-7 (estrogen responsive) and MDA-MB-231 (estrogen non-responsive) breast cancer cells exposed to different concentrations of genistein, daidzein, and a soy seed extract, using a high throughput LC–UDMS^E protein profiling approach. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay confirmed the dual activity of soy isoflavones on MCF-7 cells and the inhibitory effect on MDA-MB-231 cells. Proteome profiling of paramagnetic beads prepared peptides by nano-LC UDMS^E and pathway enrichment analysis revealed that isoflavones affected distinct molecular pathways in MCF-7 and MDA-MB-231 cells, such as tyrosine kinases signaling pathway, cytoskeleton organization, lipid and phospholipid catabolism, extracellular matrix degradation and mRNA splicing. Also, in MCF-7 cells, low and high isoflavone doses induced different changes of the proteome, including cell cycle alterations. Therefore, the expression of estrogen receptors and the isoflavone dose are determinant factors for the molecular impact of isoflavones and must be taken into account when considering adjuvant breast cancer therapy towards personalized medicine.

Soy isoflavones ameliorate the cognitive dysfunction of Goto-Kakizaki rats by activating the Nrf2-HO-1 signalling pathway

Soy isoflavones (SIF) are soybean phytochemicals that are considered to be biologically active components that protect from neurodegenerative diseases. In this study, the therapeutic effect of SIF was evaluated in a diabetic Goto-Kakizaki (GK) rat model. Twenty male GK rats were randomly divided into diabetes mellitus (DM) model group and SIF+DM group (n=10 in each group). Twenty age-matched male Wistar rats were randomly divided into control group (CON group) and CON+SIF group, with 10 rats in each group. The learning and memory functions of the animals were determined by the Morris water maze (MWM) test. Hematoxylin-eosin staining (HE) was performed to examine pyramidal neuron loss in the CA1 area of the hippocampus. Markers of oxidative stress (OS) were measured to evaluate oxidative stress-mediated injury. RT-PCR and western blotting were used to analyze the expression of nuclear factorerythroid2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1) and NAD(P)H dehydrogenase quinone1 (NQO1). Treatment with SIF for 4 weeks alleviated the cognitive dysfunction of the GK rats as determined by the MWM test. Moreover, SIF treatment also reduced diabetes-related oxidative reactions. In addition, SIF enhanced the expression of Nrf2, HO-1 and NQO1, suggesting a potential antioxidation mechanism for the effect of SIF. These findings suggest that SIF can be considered candidates for inhibiting the progression of diabetes-induced cognitive dysfunction, provide novel insights into the antioxidant effect of SIF and further strengthen the link between oxidative stress and diabetes.

Associations of equol-producing status with white matter lesion and amyloid-β deposition in cognitively normal elderly Japanese

INTRODUCTION

Equol, a metabolite of a soy isoflavone transformed by the gut microbiome, is anti-oxidant and anti-amyloidogenic. We assessed the associations of equol with white matter lesion normalized to total brain volume (WML%) and amyloid beta (Aβ) deposition.

METHODS

From 2016 to 2018, 91 cognitively normal elderly Japanese aged 75 to 89 underwent brain magnetic resonance imaging and positron emission tomography using 11C-Pittsburgh compound-B. Serum equol was measured using stored samples from 2008 to 2012. Equol producers were defined as individuals with serum levels >0. Producers were further divided into high (> the median) and low (≤ the median) producers.

RESULTS

The median (interquartile range) WML% was 1.10 (0.59 to 1.61); 24.2% were Aβ positive, and 51% were equol producers. Equol-producing status (non-producers, low and high) was significantly inversely associated with WML%: 1.19, 0.89, and 0.58, respectively (trend P < .01). Equol-producing status was not associated with Aβ status.

DISCUSSION

A randomized-controlled trial of equol targeting WML volume is warranted.

Preparation and Characterization of Soy Isoflavones Nanoparticles Using Polymerized Goat Milk Whey Protein as Wall Material

Soy isoflavones (SIF) are a group of polyphenolic compounds with health benefits. However, application of SIF in functional foods is limited due to its poor aqueous solubility. SIF nanoparticles with different concentrations were prepared using polymerized goat milk whey protein (PGWP) as wall material. The goat milk whey protein was prepared from raw milk by membrane processing technology. The encapsulation efficiencies of all the nanoparticles were found to be greater than 70%. The nanoparticles showed larger particle size and lower zeta potential compared with the PGWP. Fourier Transform Infrared Spectroscopy indicated that the secondary structure of goat milk whey protein was changed after interacting with SIF, with transformation of α-helix and β-sheet to disordered structures. Fluorescence data indicated that interactions between SIF and PGWP decreased the fluorescence intensity. All nanoparticles had spherical microstructure revealed by Transmission Electron Microscope. Data indicated that PGWP may be a good carrier material for the delivery of SIF to improve its applications in functional foods.

The Combination of Soy Isoflavones and Resveratrol Preserve Bone Mineral Density in Hindlimb-Unloaded Mice

It is well known that physical inactivity during space flight or prolonged bed rest causes rapid bone loss. Soy isoflavones (ISOs) and resveratrol (RES) have been reported to be useful to maintain a positive balance for bone turnover. Therefore, we examined the combined effects of ISO and RES on bone loss that was induced by hindlimb-unloading in mice. Female eight-week-old ddY mice were divided into the following six groups (n = 6-8 each): normally housed mice, loading mice, hindlimb-unloading (UL) mice fed a control diet, UL mice fed a 0.16% ISO conjugates, UL mice fed a 0.15% RES diet, and UL mice fed a 0.16% ISO and 0.15% RES diet. After three weeks, femoral bone mineral density was markedly decreased in unloading mice. The combination of ISO and RES prevented bone loss and especially maintained the trabecular bone mineral density more effectively compared with cortical bones. ISO and/or RES inhibited the increase in the RANKL/OPG expression ratio in bone marrow cells in UL mice. These results suggest that the combination of ISO and RES had a preventive effect against bone loss induced by hindlimb-unloading in mice. These osteoprotective effects of ISO and RES may result from the inhibition of bone resorption.

Metabolism of Soy Isoflavones by Intestinal Bacteria: Genome Analysis of an Adlercreutzia Equolifaciens Strain That Does Not Produce Equol

Isoflavones are transformed in the gut into more estrogen-like compounds or into inactive molecules. However, neither the intestinal microbes nor the pathways leading to the synthesis of isoflavone-derived metabolites are fully known. In the present work, 73 fecal isolates from three women with an equol-producing phenotype were considered to harbor equol-related genes by qPCR. After typing, 57 different strains of different taxa were tested for their ability to act on the isoflavones daidzein and genistein. Strains producing small to moderate amounts of dihydrodaidzein and/or O-desmethylangolensin (O-DMA) from daidzein and dihydrogenistein from genistein were recorded. However, either alone or in several strain combinations, equol producers were not found, even though one of the strains, W18.34a (also known as IPLA37004), was identified as Adlercreutzia equolifaciens, a well-described equol-producing species. Analysis and comparison of A. equolifaciens W18.34a and A. equolifaciens DSM19450^T (an equol producer bacterium) genome sequences suggested a deletion in the former involving a large part of the equol operon. Furthermore, genome comparison of A. equolifaciens and Asaccharobacter celatus (other equol-producing species) strains from databases indicated many of these also showed deletions within the equol operon. The present results contribute to our knowledge to the activity of gut bacteria on soy isoflavones.

The effects of soy isoflavones on total testosterone and follicle-stimulating hormone levels in women with polycystic ovary syndrome: a systematic review and meta-analysis

OBJECTIVES

The aims of this systematic review and meta-analysis were to evaluate the effectiveness of soy isoflavones on serum levels of total testosterone (TT) and follicle-stimulating hormone (FSH) in women with polycystic ovary syndrome (PCOS).

METHODS

A meta-analysis was performed by searching for relevant randomised controlled trials (RCTs) in several databases. Of the four trials found, the eligibility criteria to evaluate the efficacy of soy isoflavones on serum levels of FSH were met by three trials and of TT by four trials. The Cochrane scale was used to evaluate the risk of bias. Fixed-effects and random-effects models were used to evaluate overall effect. The χ ² test (Cochran's Q test) and the I ² index were used to assess the heterogeneity of RCTs.

RESULTS

Our results showed that soy isoflavones significantly decreased TT (weighted mean difference [WMD] - 0.14; 95% confidence interval [CI] - 0.2, -0.02; p = 0.016; I ² = 89%, p < 0.001) but had no significant effect on FSH levels (WMD -0.25; 95% CI -0.54, 0.02; p = 0.06; I ² = 0%, p = 0.85).

CONCLUSION

Although the results of this meta-analysis showed that soy isoflavones in women with PCOS decreased TT and had no significant effect on FSH, better and more valid studies are needed to confirm these results.

Effects of soy isoflavones on serum systemic and vascular inflammation markers and oxidative stress in peritoneal dialysis patients: A randomized controlled trial

Cardiovascular disease (CVD) is common in peritoneal dialysis (PD) patients. This study was designed to investigate the effects of isoflavones on systemic and vascular inflammation markers and oxidative stress in PD patients. In this randomized clinical trial, 40 PD patients were randomly assigned to either the isoflavone or the placebo group. The isoflavone group received 100 mg soy isoflavones daily for 8 weeks, whereas the placebo group received corresponding placebos. At baseline and the end of eighth week, serum high sensitive C-reactive protein (hs-CRP), intercellular adhesion molecule type 1 (ICAM-1), vascular cell adhesion molecule type 1 (VCAM-1), E-selectin, and malondialdehyde were measured. Serum VCAM-1 decreased significantly in the isoflavone group at the end of Week 8 compared to baseline (p = .01), whereas no significant change was observed in the placebo group. Serum ICAM-1 decreased significantly in the isoflavone (p = .01) and placebo (p = .01) group compared to baseline. However, the reduction of ICAM-1 was significantly higher in the isoflavone group than in the placebo group (p = .02). There were no significant differences between the two groups in mean changes of serum E-selectin, malondialdehyde, and hs-CRP. This study indicates that isoflavones reduce serum VCAM-1 and ICAM-1, which are two CVD risk factors, in PD patients.

Soy isoflavones improve the oxidative stress induced hypothalamic inflammation and apoptosis in high fat diet-induced obese male mice through PGC1-alpha pathway

Obesity is a common metabolic disorder that increases the risk of many diseases, such as type II diabetes, hypertension, cardiovascular disease. Hypothalamus plays a very important role in the progression of obesity, and many studies reveal that hypothalamic injures are implicated in obesity processes. Here, we describe that the consumption of soy isoflavones, with a structural similarity to that of estradiol, could mitigate obesity through improving the hypothalamic inflammation and apoptosis, which are induced by oxidative stress. Also, our in vitro studies demonstrate that daidzein and genistein, common ingredients of soy isoflavones, could protect hypothalamic N42 cells against palmitic acid induced oxidative stress and apoptosis. Moreover, the transcriptional coactivator peroxisome proliferator-activated receptor γ coactivator 1 alpha (PGC1-alpha), which plays a role in oxidative defense, is increased after soy isoflavone treatment in vivo and in vitro, suggesting an improved effect of soy isoflavones on hypothalamic antioxidant defense is mediated by PGC-1α. Our study reveals a potential mechanism of soy isoflavones regulating oxidative stress induced hypothalamic inflammation and cellular apoptosis, which will be important for obesity treatment.

Genistin: A Novel Potent Anti-Adipogenic and Anti-Lipogenic Agent

Soy isoflavones are popular ingredients with anti-adipogenic and anti-lipogenic properties. The anti-adipogenic and anti-lipogenic properties of genistein are well-known, but those of genistin and glycitein remain unknown, and those of daidzein are characterized by contrasting data. Therefore, the purpose of our study was to investigate the effects of daidzein, glycitein, genistein, and genistin on adipogenesis and lipogenesis in 3T3-L1 cells. Proliferation of 3T3-L1 preadipocytes was unaffected by genistin and glycitein, but it was affected by 50 and 100 µM genistein and 100 µM daidzein for 48 h. Among the four isoflavones, only 50 and 100 µM genistin and genistein markedly suppressed lipid accumulation during adipogenesis in 3T3-L1 cells through a similar signaling pathway in a dose-dependent manner. Genistin and genistein suppress adipocyte-specific proteins and genes, such as peroxisome proliferator-activated receptor γ (PPARγ), CCAAT-enhancer-binding protein α (C/EBPα), and adipocyte binding protein 2 (aP2)/fatty acid-binding protein 4 (FABP4), and lipogenic enzymes such as ATP citrate lyase (ACL), acetyl-CoA carboxylase 1 (ACC1), and fatty acid synthase (FAS). Both isoflavones also activate AMP-activated protein kinase α (AMPKα), an essential factor in adipocyte differentiation, and inhibited sterol regulatory element-binding transcription factor 1c (SREBP-1c). These results indicate that genistin is a potent anti-adipogenic and anti-lipogenic agent.

[Effects of resveratrol and soy isoflavones on learning and memory ability and expression of glucose transporter in aging model rats]

OBJECTIVE

To investigate the effects of resveratrol combined with soy isoflavones on avoidance memory, number of neuron-specific nuclear protein(NeuN) positive cells and expressions of glucose transporter(GLUT)1 and GLUT3 in hippocampus of aging model rats.

METHODS

A total of 60 female SD rats were randomly divided into 6 groups including sham control group, aging model group, 80 mg/kg resveratrol group, 160 mg/kg soy isoflavones group, 80 mg/kg resveratrol +160 mg/kg soy isoflavones group, 0. 8 mg/kg estradiol valerate group. The aging model rats was induced by ovariectomy combined with intraperitoneal injection of 100 mg/kg D-galactose. Intragastric administration was performed once a day for 12 weeks. The avoidance task was measured by the shuttle box test. The NeuN expression were measured by the immunofluorescence. The genes and proteins expression of GLUT1 and GLUT3 in rat hippocampus were detected by real-time PCR and Western blot, respectively.

RESULTS

Compared with the sham control group, the avoidance latency in the aging model group was prolonged, and the active avoidance response rate and the total avoidance response rate were decreased. The number of NeuN positive cells decreased and the expression levels of GLUT1 and GLUT3 genes and proteins were decreased(P&lt;0. 05). Compared with the aging model group, the escape latency significantly declined(P&lt;0. 01), but the rates of active avoidance response and total avoidance response increased, the number of NeuN positive cells increased significantly, the expression levels of GLUT1 and GLUT3 genes and proteins up-regulated in the rats of the three intervention groups(P&lt;0. 05 or P&lt;0. 01). Compared with the soy isoflavones group, the active avoidance response rate was increased in the combined group(P&lt;0. 05). In comparison with those for the resveratrol group, the avoidance latency was shortened and the active avoidance response rate was increased, the number of NeuN positive cells and the expression levels of GLUT3 gene and protein were significantly increased in the combined group(P&lt;0. 05). There was no significant difference between the combined intervention group and the estradiol valerate group(P&gt;0. 05).

CONCLUSION

Resveratrol and soy isoflavones alone and in combination can improve the learning and memory ability of aging rat models. The mechanism may be related to up-regulating the expression of GLUT1 and GLUT3 genes and proteins in the hippocampus, promoting the transmembrane transport of glucose and reducing neuronal loss.

Isoflavone-mediated radioprotection involves regulation of early endothelial cell death and inflammatory signaling in Radiation-Induced lung injury

Purpose: Vascular damage and inflammation are limiting toxic effects of lung cancer radiotherapy, which lead to pneumonitis and pulmonary fibrosis. We have demonstrated that soy isoflavones (SIF) mitigate these toxic effects at late time points after radiation. However, the process by which SIF impacts the onset of radiation-induced inflammation remains to be elucidated. We have now investigated early events of radiation-induced inflammation and identified cellular and molecular signaling patterns by endothelial cells that could be modified by SIF to control vascular damage and the initiation of lung inflammation.Materials and methods: Histopathological, cellular and molecular studies were performed on mouse lungs from C57Bl/6 mice treated with 10 Gy of thoracic radiation (XRT) in conjunction with daily oral SIF treatment given prior and after radiation. Parallel studies were performed in-vitro using EA.hy926 endothelial cell line with SIF and radiation. Immunohistochemistry, western blots analysis, and flow cytometry were performed on lung tissue or EA.hy926 cells to analyze endothelial cells, their patterns of cell death or survival, and signaling molecules involved in inflammatory events.Results: Histopathological differences in inflammatory infiltrates and vascular injury in lungs, including vascular endothelial cells, were observed with SIF treatment at early time points post-XRT. XRT-induced expression of proinflammatory adhesion molecule ICAM-1 cells was reduced by SIF in-vitro and in-vivo in endothelial cells. Molecular changes in endothelial cells with SIF treatment in conjunction with XRT included increased DNA damage, reduced cell viability and cyclin B1, and inhibition of nuclear translocation of NF-κB. Analysis of cell death showed that SIF treatment promoted apoptotic endothelial cell death and decreased XRT-induced type III cell death. In-vitro molecular studies indicated that SIF + XRT increased apoptotic caspase-9 activation and production of IFNβ while reducing the release of inflammatory HMGB-1 and IL-1α, the cleavage of pyroptotic gasdermin D, and the release of active IL-1β, which are all events associated with type III cell death.Conclusions: SIF + XRT caused changes in patterns of endothelial cell death and survival, proinflammatory molecule release, and adhesion molecule expression at early time points post-XRT associated with early reduction of immune cell recruitment. These findings suggest that SIF could mediate its radioprotective effects in irradiated lungs by limiting excessive immune cell homing via vascular endothelium into damaged lung tissue and curtailing the overall inflammatory response to radiation.

Soy Isoflavones Improve the Spermatogenic Defects in Diet-Induced Obesity Rats through Nrf2/HO-1 Pathway

Soy isoflavones (SIF) are biologically active compounds of non-steroidal and phenolic properties that are richly present in soybeans, which can reduce the body weight and blood lipids of obese animals. Recently, SIF have been reported to affect reproductive ability in obese male rats. However, the specific mechanism has not been well defined. The aim of the current study was to study the possible mechanisms for the effect of SIF administration on obesity induced spermatogenic defects. Obese rats model induced by high-fat diets were established and gavage treated with 0, 50,150 or 450 mg of SIF/kg body weight/day for 4 weeks. Here, our research shows that obesity resulted in spermatogenic degeneration, imbalance of reproductive hormone, testicular oxidative stress and germ cell apoptosis, whereas evidently recovery effects were observed at 150 and 450 mg/kg SIF. We also have discovered that 150 and 450 mg/kg SIF can activate Nrf2/HO-1 pathway in control of Bcl-2, BAX and cleaved caspase-3 expression with implications in antioxidant protection. Our study indicates the potential mechanism of SIF regulating spermatogenic function in obese rats, and provides a scientific experimental basis for the regulation of biological function of obese male reproductive system by SIF.

Soy Isoflavones Ameliorate Fatty Acid Metabolism of Visceral Adipose Tissue by Increasing the AMPK Activity in Male Rats with Diet-Induced Obesity (DIO)

Soy isoflavones are natural active ingredients of soy plants that are beneficial to many metabolic diseases, especially obesity. Many studies have reported that obesity is closely related to visceral fatty acid metabolism, but the effect has not been well defined. In this study, we show that soy isoflavones improve visceral fatty acid metabolism in diet-induced obese male rats, which was indicated by reduced body weight and visceral fat cell area, as well as suppressed visceral fat synthesis and accelerated fat hydrolysis. We also found that common components of soy isoflavones, daidzein and genistein, were able to inhibit the lipid accumulation process in 3T3-L1 cells. Moreover, we showed that soy isoflavones can promote on AMP-activated protein kinase (AMPK) activity both in vivo and in vitro, which may be implicated in lipid metabolism regulation of soy isoflavones. Our study demonstrates the potential of soy isoflavones as a mechanism for regulating lipid homeostasis in visceral adipose tissue, proven to be beneficial for obesity treatment.

Soy isoflavones protect against oxidative stress and diminish apoptosis in ovary of middle-aged female rats

Ovarian aging is characterized by declines in follicular reserve and oocyte quality due, in part, to increased oxidative stress and apoptosis. Soy isoflavones (ISOs) have been shown to improve ovarian lifespan by acting as antioxidant and antiapoptotic agents. We aimed at evaluating whether ISOs could modulate oxidative stress and reduce apoptosis and improve ovarian follicle survival in middle-aged female rats. Twelve ovary-intact female Wistar rats (12-month-old) were divided into groups: control (CTRL) and ISO, daily treated by gavage with vehicle or soy-ISO extract (150 mg/kg b.w), respectively. After 8 weeks, rats were euthanized and their ovaries removed for histomorphometric (% follicles) and apoptosis (cleaved-caspase-3/BCL2 immunostaining) evaluations, or subjected to biochemical assays to survey reactive oxygen species (ROS) and lipid peroxidation levels and total antioxidant capacity (TAC). The frequency of atretic follicles and number of cleaved-caspase-3-positive cells, as well as the ROS and lipid peroxidation levels, were significantly lower in ISO group compared to CTRL. A significantly higher number of BCL2-positive cells and TAC levels were also observed in ISO group. In conclusion, soy ISOs could decrease follicular atresia, apoptosis and oxidative stress, as well as increase the TAC in ovaries of female rats.

Exploring in vitro effects of biotransformed isoflavones extracts: Antioxidant, antiinflammatory, and antilipogenic

The present study aimed to investigate, in in vitro assays, the antilipogenic and antiinflammatory potential as well as the antioxidant capacity of biotransformed soymilk by tannase and β-glycosidase enzymes. The results showed a significant enhancement of the antioxidant capacity, especially by biotransformed soymilk with free tannase (SFT), corresponding to an increase of 2.3 and 1.25 times by oxygen radical absorbance capacity (ORAC) and ferric reducing antioxidant power (FRAP) assays, respectively. The lipid accumulation reduction by 3T3-L1 adipocytes assay was not significant. However, the antiinflammatory responses were expressive. In lipopolysaccharide-stimulated RAW 264.7 macrophages, SFT reduced around 37 times TNF-α expression at the highest tested concentration of the sample. Other inflammatory parameters, as IL-6 and nitric oxide, were no longer detected when the cells were treated with SFT and soymilk with immobilized enzymes, respectively. The biotransformed soy extracts with tannase have great potential to act as a nutraceutical, protecting the cells against oxidative damage and helping maintain health under inflammatory stress. PRACTICAL APPLICATIONS: Soy isoflavones have been associated with several beneficial effects on human health, including inhibition capacity of lipid accumulation in adipocytes, antiinflammatory properties, and antioxidant potential. However, the isoflavones bioavailability differs among their chemical forms, and studies have shown that the higher health benefits are conferred by aglycones and their metabolites, such as equol, compared to the other forms. For this reason, the enrichment of isoflavone aglycones and metabolites in soy-based products has attracted growing attention. The present study was focused on developing a bioprocess able to produce a rich extract with soy isoflavones metabolites, with increased bioactive potential for application as a functional ingredient or a nutraceutical.

Improvement of Colonic Immune Function with Soy Isoflavones in High-Fat Diet-Induced Obese Rats

Background: The damage to intestinal barrier function plays an important role in the development of obesity and associated diseases. Soy isoflavones are effective natural active components for controlling obesity and reducing the level of blood lipid. Here, we explored whether these effects of soy isoflavones were associated with the intestinal barrier function. Methods and Results: The obese rat models were established by high fat diet feeding. Then, those obese rats were supplemented with soy isoflavones at different doses for 4 weeks. Our results showed that obesity induced the expressions of pro-inflammatory cytokines, decreased the anti-inflammatory cytokine (IL-10) expression, elevated intestinal permeability, altered gut microbiota and exacerbated oxidative damages in colon. The administration of soy isoflavones reversed these changes in obese rats, presenting as the improvement of intestinal immune function and permeability, attenuation of oxidative damage, increase in the fraction of beneficial bacteria producing short-chain fatty acids and short-chain fatty acid production, and reduction in harmful bacteria. Furthermore, soy isoflavones blocked the expressions of TLR4 and NF-κB in the colons of the obese rats. Conclusions: Soy isoflavones could improve obesity through the attenuation of intestinal oxidative stress, recovery of immune and mucosal barrier, as well as re-balance of intestinal gut microbiota.

Prostate cancer metastasis and soy isoflavones: a dogfight over a bone

Prostate cancer is a complex, progressive, bone-tropic disease, which is usually associated with skeletal issues, poor mobility and a fatal outcome when it reaches the metastatic phase. Soy isoflavones, steroid-like compounds from soy-based food/dietary supplements, have been found to decrease the risk of prostate cancer in frequent consumers. Herein, we present a systematization of the data on soy isoflavone effects at different stages of metastatic prostate cancer progression, with a particular interest in the context of bone-related molecular events. Specifically, soy isoflavones have been determined to downregulate the prostate cancer cell androgen receptors, reverse the epithelial to mesenchymal transition of these cells, decrease the expressions of prostate-specific antigen, matrix metalloproteinase and serine proteinase, and reduce the superficial membrane fluidity in prostate cancer cells. In addition, soy isoflavones suppress the angiogenesis that follows prostate cancer growth, obstruct prostate cancer cells adhesion to the vascular endothelium and their extravasation in the area of future bone lesions, improve the general bone morphofunctional status, have a beneficial effect on prostate cancer metastasis-caused osteolytic/osteoblastic lesions and possibly affect the pre-metastatic niche formation. The observed, multilevel antimetastatic properties of soy isoflavones imply that they should be considered as promising components of combined therapeutic approaches to advanced prostate cancer.

Lack of combination effects of soy isoflavones and taxane chemotherapy of castration-resistant prostate cancer

BACKGROUND

Patients with cancer, including prostate cancer, often use dietary supplements, such as soy or isoflavones, before, during, or after therapy. There is little information about possible interactions between supplements and cancer chemotherapy. There are some reports suggesting enhancement by genistein of taxane chemotherapy for castrate-resistant prostate cancer (CRPC).

METHODS

We investigated whether physiologically attainable concentrations of soy isoflavones (≤10 μM) interact with taxanes on growth inhibition of CRPC cells in vitro and in vivo in nude mice exposed via the diet, on microtubule disassembly in vitro, and on P-glycoprotein-mediated drug efflux in 22Rv1 cells and CYP3A4 activity in microsomes.

RESULTS

Genistein, daidzein, and equol did not affect growth of VCaP, 22Rv1, C4-2, and PC-3 CRPC cells or growth inhibition of these cells by docetaxel and cabazitaxel. These isoflavones did not inhibit microtubule disassembly in vitro or inhibit the microtubule effects of taxanes and genistein did not bind substantially to microtubules. Genistein considerably inhibited P-glycoprotein-mediated drug efflux in 22Rv1 cells and CYP3A4 activity in microsomes. However, dietary supplementation with genistein at 250 and 500 ppm did not affect the tumor growth inhibiting effect of docetaxel on 22Rv1 cells xenografted in nude mice.

CONCLUSIONS

Our results with relevant cell models and clinically achievable concentrations of soy isoflavones do not support the notion that genistein or other soy isoflavones can enhance the effects of taxane chemotherapy in CRPC cell and xenograft models. Yet, the inhibitory effects of genistein on drug efflux in 22Rv1 cells and on microsomal CYP3A4 activity raise the possibility that genistein can affect taxane effects on CRPC cells in other circumstances than those we studied, which merits further research.

Soy Isoflavones and their Effects on Xenobiotic Metabolism

BACKGROUND

Soy isoflavones, such as genistein and daidzein, are bioflavonoids found in soy products that are able to interact with various hormones such as estrogen. Epidemiological studies reveal a proper level of isoflavones in diet can prevent many diseases like cancers or diabetes. Therefore, it is important to study the biotransformation and xenobiotic metabolism of soy isoflavones.

METHODS

A systematic review of published studies was carried out to investigate the characterization of isoflavones and their metabolites, sample pretreatment and quantitative analysis of isoflavones, and the influence of soy isoflavones on drug and xenobiotic metabolism.

RESULTS

Aglycones with weak estrogen-like activities are the biologically active forms of the soy isoflavones in mammals. The most recent advances including extraction, purification and detection of isoflavones in soybean and soy products are discussed. The effects of soy isoflavones on drug and xenobiotic metabolism involve in regulation of phase I cytochrome P450 (CYPs) enzyme and phase I detoxifying enzymes expression and activity. At the molecular level, soy isoflavones have proved capable of estrogenic/antiestrogenic with tissue-selective, anti-cancer, antiobesity, anti-oxidation, and tyrosine kinase inhibition activities.

CONCLUSION

This review summarized different aspects of soy isoflavones and their molecular mechanisms of pharmacological action on xenobiotic, which demonstrated that soy isoflavones can decrease the incidence of many diseases and benefit for human health. However, since the lack of clinical research for evaluation of the proper dosage of intake of soy isoflavones in diet or adjunctive therapy, there is a need for further studies on the selection of doses, biomedical applications and adverse effects of isoflavones for human health.

Androgen receptor and soy isoflavones in prostate cancer

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.

Neuroprotective Effects of Soy Isoflavones on Scopolamine-Induced Amnesia in Mice

In the recent years, interest in soybean as a neuroprotective nutrient in the management of Alzheimer’s disease (AD) has increased and soy isoflavones (SI), as kinds of soybean phytochemicals, are thought to be biologically active components that confer this beneficial effect against neurodegenerative diseases. However, the neuroprotective effect of SI is not well understood. Therefore, the present study (30 days) was conducted to investigate the neuroprotective effects of soy isoflavones (SI) on scopolamine (SCOP)-induced memory impairments in Institute of Cancer Research (ICR) mice (aged 4 weeks) and to elucidate its underlying mechanisms of action. SI (40 mg/kg) administration improved the cognitive performance of SCOP-treated mice in an object location recognition task and the Morris water maze test. SI (40 mg/kg) administration significantly enhanced cholinergic system function and suppressed oxidative stress levels in the hippocampus of SCOP-treated mice. Furthermore, SI (40 mg/kg) treatment markedly upregulated the phosphorylation levels of extracellular signal-regulated kinase (ERK), cAMP response element-binding protein (CREB) and brain-derived neurotrophic factor (BDNF) expression levels in the hippocampus. Taken together, these results demonstrated that soy isoflavones exerted a significant neuroprotective effect on cognitive dysfunctions induced by scopolamine, suggesting that soy isoflavones could be a good candidate for possible treatment of neurodegenerative diseases, such as Alzheimer’s disease (AD).

Somatopause, weaknesses of the therapeutic approaches and the cautious optimism based on experimental ageing studies with soy isoflavones

The pathological phenomenon of somatopause, noticeable in hypogonadal ageing subjects, is based on the growth hormone (GH) production and secretion decrease along with the fall in GH binding protein and insulin-like growth factor 1 (IGF-1) levels, causing different musculoskeletal, metabolic and mental issues. From the perspective of safety and efficacy, GH treatment is considered to be highly controversial, while some other therapeutic approaches (application of IGF-1, GH secretagogues, gonadal steroids, cholinesterase-inhibitors or various combinations) exhibit more or less pronounced weaknesses in this respect. Soy isoflavones, phytochemicals that have already demonstrated the health benefits in treated elderly, at least experimentally reveal their potential for the somatopausal symptoms remediation. Namely, genistein enhanced GHRH-stimulated cAMP accumulation and GH release in rat anterior pituitary cells; refreshed and stimulated the somatotropic system (hypothalamic nuclei and pituitary GH cells) function in a rat model of the mild andropause, and stimulated the GH output in ovariectomized ewes as well as the amplitude of GH pulses in the rams. Daidzein, on the other hand, increased body mass, trabecular bone mass and decreased bone turnover in the animal model of severe andropause, while both isoflavones demonstrated blood cholesterol-lowering effect in the same model. These data, which necessarily need to be preclinically and clinically filtered, hint some cautious optimism and call for further innovative designing of balanced soy isoflavone-based therapeutics.