Molecular basis of the inhibition of human aromatase (estrogen synthetase) by flavone and isoflavone phytoestrogens: A site-directed mutagenesis study

The chronic alcohol consumption influences the gonadal axis in men: Results from a meta-analysis

BACKGROUND

Low testosterone concentrations affect 2-13% of adult males, with a direct association between reduction in testosterone (T) concentrations and cardiovascular events. Lifestyle habits have been linked to visceral fat accumulation and endocrine disorders like secondary hypogonadism. Alcohol intake has also been a topic of debate, with studies showing a detrimental effect on sperm production and underlying mechanisms. This meta-analysis aims to comprehensively evaluate the effect of alcohol consumption on T serum concentrations in adult men.

METHODS

The literature search included only controlled clinical trials comparing men who drink alcohol to men who do not, or who assumed placebo or nonalcoholic beverages. The primary outcome was the comparison of total testosterone serum concentrations between the study and control groups. The publications were examined for publication bias using Egger's test.

RESULTS

Twenty-one studies were included in the analysis for a total of 30 trials that examined the effects of alcohol consumption on testosterone level in 10,199 subjects. The meta-analysis showed that alcohol consumption overall is related to significant reduction in circulating concentrations of total testosterone (mean difference [MD] = -4.02; 95% CI -6.30, -1.73), free T (MD = -0.17; 95% CI -0.23, -0.12), sex hormone binding globulin (SHBG) (MD = -1.94; 95% CI -3.37, -0.48), an increase in estradiol (E2) (MD = 7.65; 95% CI 1.06, 14.23) and neutral effect on luteinizing hormone (LH) (MD = -0.15; 95% CI -0.36, 0.06), independently by age, body mass index (BMI), E2, and LH serum concentrations and alcohol intake. However, these results are evident only in healthy men exposed to chronic alcohol consumption and not in those with a recognized diagnosis of alcohol use disorder or after acute alcohol intake.

CONCLUSION

This study suggests how chronic alcohol consumption may inhibit the gonadal axis in healthy men, although the exact pathophysiological mechanisms connecting alcohol exposure and steroidogenesis are still not completely clarified.

Development of dietary small molecules as multi-targeting treatment strategies for Alzheimer's disease

Cognitive dysfunction can occur both in normal aging and age-related neurological disorders, such as mild cognitive impairment and Alzheimer's disease (AD). These disorders have few treatment options due to side effects and limited efficacy. New approaches to slow cognitive decline are urgently needed. Dietary interventions (nutraceuticals) have received considerable attention because they exhibit strong neuroprotective properties and may help prevent or minimize AD symptoms. Biological aging is driven by a series of interrelated mechanisms, including oxidative stress, neuroinflammation, neuronal apoptosis, and autophagy, which function through various signaling pathways. Recent clinical and preclinical studies have shown that dietary small molecules derived from natural sources, including flavonoids, carotenoids, and polyphenolic acids, can modulate oxidative damage, cognitive impairments, mitochondrial dysfunction, neuroinflammation, neuronal apoptosis, autophagy dysregulation, and gut microbiota dysbiosis. This paper reviews research on different dietary small molecules and their bioactive constituents in the treatment of AD. Additionally, the chemical structure, effective dose, and specific molecular mechanisms of action are comprehensively explored. This paper also discusses the advantages of using nanotechnology-based drug delivery, which significantly enhances oral bioavailability, safety, and therapeutic effect, and lowers the risk of adverse effects. These agents have considerable potential as novel and safe therapeutic agents that can prevent and combat age-related AD.

A Review on the Role of Phytoconstituents Chrysin on the Protective Effect on Liver and Kidney

BACKGROUND

The chance of contracting significant diseases increases due to an unhealthy and contemporary lifestyle. Chrysin is a flavonoid of the flavone class in numerous plants, including Passiflora and Pelargonium. Chrysin has long been used to treat a variety of illnesses. Chrysin, an essential flavonoid, has many pharmacological actions, including anticancer, antiviral, anti-inflammatory, anti-arthritic, depressive, hypolipidemic, hepatoprotective, and nephroprotective activity.

PURPOSE

This explorative review was commenced to provide a holistic review of flavonoids confirming that Chrysin has a therapeutic potential on the liver and kidney and reduces the hepatotoxicity and nephrotoxicity induced by diverse toxicants, which can be helpful for the toxicologists, pharmacologists, and chemists to develop new safer pharmaceutical products with chrysin and other toxicants.

STUDY DESIGN

The most relevant studies that were well-explained and fit the chosen topic best were picked. The achieved information was analyzed to determine the outcome by screening sources by title, abstract, and whole work. Between themselves, the writers decided on the studies to be considered. The necessary details were systematically organized into titles and subtitles and compressively discussed.

METHOD

The information presented in this review is obtained using targeted searches on several online platforms, including Google Scholar, Scifinder, PubMed, Science Direct, ACS publications, and Wiley Online Library. The works were chosen based on the inclusion criteria agreed upon by all authors.

RESULTS

Chrysin is a promising bioactive flavonoid with significant health benefits, and its synthetic replacements are being utilized as pharmaceuticals to treat various diseases. Findings revealed that Chrysin exhibits hepatoprotective actions against several hepatotoxicants like 2,3,7,8 tetrachlorodibenzo- p-dioxin, carbon tetrachloride (CCl4), cisplatin, and others by lowering the levels of liver toxicity biomarkers and enhancing antioxidant levels. Additionally, chrysin has potential nephroprotective properties against various nephrotoxicants, like Cisplatin, Doxorubicin, Paracetamol, Gentamicin, Streptazosin, and others by dropping kidney toxicity marker levels, reducing oxidative stress, and improving the antioxidant level.

CONCLUSION

According to this revised study, chrysin is a promising phytoconstituent that can be utilized as an alternate treatment for various medications that cause hepatotoxicity and nephrotoxicity. With active chrysin, several dosage forms targeting the liver and kidneys can be formulated.

A mechanistic toxicology study to grasp the mechanics of zearalenone estrogenicity: Spotlighting aromatase and the effects of its genetic variability

Zearalenone (ZEN) is a mycoestrogen produced by Fusarium fungi contaminating cereals and in grain-based products threatening human and animal health due to its endocrine disrupting effects. Germane to the mechanisms of action, ZEN may activate the estrogen receptors and inhibit the estrogens-producing enzyme aromatase (CYP19A1). Both show single nucleotide variants (SNVs) among humans associated with a diverse susceptibility of being activated or inhibited. These variations might modify the endocrine disrupting action of ZEN, requiring dedicated studies to improve its toxicological understanding. This work focused on human aromatase investigating via 3D molecular modelling whether some of the SNVs reported so far (n = 434) may affect the inhibitory potential of ZEN. It has been also calculated the inhibition capability of α-zearalenol, the most prominent and estrogenically potent phase I metabolite of ZEN, toward those aromatase variants with an expected diverse sensitivity of being inhibited by ZEN. The study: i) described SNVs likely associated with a different susceptibility to ZEN and α-zearalenol inhibition - like T310S that is likely more susceptible to inhibition, or D309G and S478F that are possibly inactive variants; ii) proofed the possible existence of inter-individual susceptibility to ZEN; iii) prioritized aromatase variants for future investigations toward a better comprehension of ZEN xenoestrogenicity at an individual level.

Breast cancer prevention with liquiritigenin from licorice through the inhibition of aromatase and protein biosynthesis in high-risk women's breast tissue

Breast cancer risk continues to increase post menopause. Anti-estrogen therapies are available to prevent postmenopausal breast cancer in high-risk women. However, their adverse effects have reduced acceptability and overall success in cancer prevention. Natural products such as hops (Humulus lupulus) and three pharmacopeial licorice (Glycyrrhiza) species have demonstrated estrogenic and chemopreventive properties, but little is known regarding their effects on aromatase expression and activity as well as pro-proliferation pathways in human breast tissue. We show that Gycyrrhiza inflata (GI) has the highest aromatase inhibition potency among these plant extracts. Moreover, phytoestrogens such as liquiritigenin which is common in all licorice species have potent aromatase inhibitory activity, which is further supported by computational docking of their structures in the binding pocket of aromatase. In addition, GI extract and liquiritigenin suppress aromatase expression in the breast tissue of high-risk postmenopausal women. Although liquiritigenin has estrogenic effects in vitro, with preferential activity through estrogen receptor (ER)-β, it reduces estradiol-induced uterine growth in vivo. It downregulates RNA translation, protein biosynthesis, and metabolism in high-risk women's breast tissue. Finally, it reduces the rate of MCF-7 cell proliferation, with repeated dosing. Collectively, these data suggest that liquiritigenin has breast cancer prevention potential for high-risk postmenopausal women.

A Review on Polyphenols in Salicornia ramosissima with Special Emphasis on Their Beneficial Effects on Brain Ischemia

There has been an increasing interest in the consumption of halophytes as a healthy food in the last few years. Salicornia ramosissima is a seasonal Mediterranean halophyte with an interesting profile of bioactive compounds, including more than 60 identified polyphenols with a broad range of biological activities. Accumulating evidence supports the role of dietary polyphenols in the prevention of cardiovascular diseases, such as stroke. Stroke is the second cause of death worldwide and it is estimated that a substantial proportion of stroke incidence and recurrence may be prevented by healthier dietary patterns. Here, we have grouped the phenolic acids and flavonoids identified in S. ramosissima and reviewed their potential protective effect on brain ischemia, which are mostly related to the reduction of oxidative stress and inflammation, the inhibition of cell death pathways and their role in the preservation of the vascular function. Despite the fact that most of these compounds have been reported to be neuroprotective through multiple mechanisms, human studies are still scarce. Given the safe profile of polyphenols identified in S. ramosissima, this halophyte plant could be considered as a source of bioactive compounds for the nutraceutical industry.

Molecular and Cellular Mechanisms of Propolis and Its Polyphenolic Compounds against Cancer

In recent years, interest in natural products such as alternative sources of pharmaceuticals for numerous chronic diseases, including tumors, has been renewed. Propolis, a natural product collected by honeybees, and polyphenolic/flavonoid propolis-related components modulate all steps of the cancer progression process. Anticancer activity of propolis and its compounds relies on various mechanisms: cell-cycle arrest and attenuation of cancer cells proliferation, reduction in the number of cancer stem cells, induction of apoptosis, modulation of oncogene signaling pathways, inhibition of matrix metalloproteinases, prevention of metastasis, anti-angiogenesis, anti-inflammatory effects accompanied by the modulation of the tumor microenvironment (by modifying macrophage activation and polarization), epigenetic regulation, antiviral and bactericidal activities, modulation of gut microbiota, and attenuation of chemotherapy-induced deleterious side effects. Ingredients from propolis also "sensitize" cancer cells to chemotherapeutic agents, likely by blocking the activation of the transcription factor nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). In this review, we summarize the current knowledge related to the the effects of flavonoids and other polyphenolic compounds from propolis on tumor growth and metastasizing ability, and discuss possible molecular and cellular mechanisms involved in the modulation of inflammatory pathways and cellular processes that affect survival, proliferation, invasion, angiogenesis, and metastasis of the tumor.

Chrysin-Loaded Microemulsion: Formulation Design, Evaluation and Antihyperalgesic Activity in Mice

Chrysin is a bioactive flavonoid found in pollens, passion flowers, honey, royal jelly, and propolis, which is commonly used as an ingredient in natural food supplements and is primarily responsible for their pharmacological properties. A transparent chrysin-loaded microemulsion (CS-ME) prepared through a ternary phase diagram was evaluated for use as an antihyperalgesic formulation. It was formulated with 40% Labrasol® (surfactant), 5% isopropyl myristate (oil phase) and 55% water (aqueous phase) and classified as an oil-in-water (O/W) microsized system (74.4 ± 15.8 nm). Its negative Zeta potential (−16.1 ± 1.9 mV) was confirmed by polarized light microscopy and dynamic light scattering analysis. In vitro studies in Franz-type static diffusion cells showed that chrysin release from CS-ME followed zero-order kinetics. Oral administration of CS-ME in mice resulted in a statistically significantly reduction (p < 0.05) in carrageenan-induced mechanical hyperalgesia compared to the control group. Treatment with CS-ME also showed anti-inflammatory activity by significantly decreasing the TNF-α level (p < 0.01) and increasing that of IL-10 (p < 0.05) compared to the control group. These results suggest that the proposed microsystem is a promising vector for the release of chrysin, being able to improve its capacity to modulate inflammatory and nociceptive responses.

Identifying Environmental Endocrine Disruptors Associated With the Age at Menarche by Integrating a Transcriptome-Wide Association Study With Chemical-Gene-Interaction Analysis

Menarche is the first occurrence of menstrual bleeding and one of the most important events of female puberty. Alarmingly, over the last several decades, the mean age at menarche (AAM) has decreased. Environmental endocrine disruptors (EEDs) are chemicals that may interfere with the endocrine system, resulting in adverse developmental, immunological, neurological, and reproductive effects in humans. Thus, the effects of EEDs on fertility and reproduction are growing concerns in modern societies. In this study, we aimed to determine the influence of genetic and environmental factors on AAM. We used data from an AAM genome-wide association study of 329,345 women to conduct a transcriptome-wide association study (TWAS) with FUSION software. As references, we determined the gene-expression levels in the hypothalamus, pituitary gland, ovaries, uterus, and whole blood. We performed Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses using the significantly dysregulated genes identified by the TWAS. Using the STRING database, we also generated a protein-protein-interaction network to analyze common AAM-specific genes identified by the TWAS with different tissues. We performed chemical-related gene set enrichment analysis (CGSEA) and identified significant TWAS genes to uncover relationships between different chemicals and AAM. The TWAS identified 9,848 genes; among these, 1580 genes were significant (P < 0.05), and 11 genes were significant among the hypothalamus, pituitary, ovary, uterus, and whole blood. CGSEA identified 1,634 chemicals, including 120 chemicals significantly correlated with AAM. In summary, we performed a TWAS (for genetic factors) and CGSEA (for environmental factors) focusing on AAM and identified several AAM-associated genes and EEDs. The results of this study expand our understanding of genetic and environmental factors related to the onset of female puberty.

Soy isoflavones alleviate polycystic ovary syndrome in rats by regulating NF- κB signaling pathway

Soy isoflavones have been widely used in the treatment of clinical gynecological diseases. The aim of this study was to investigate the therapeutic effect and molecular mechanism of Soy isoflavones on rats with polycystic ovary syndrome (PCOS). Sprague-Dawley rats were orally administered 1 mg/kg letrozole for 21 consecutive days to induce the PCOS rat model. After PCOS induction, Soy isoflavones (100 mg/kg) or metformin (Positive control; 500 mg/kg) was administered continuously for 28 days. Then, H&E staining was used to observe the pathological changes of ovary. The serum hormone levels and the levels of antioxidant and inflammatory cytokines in ovarian tissue were detected. Additionally, the expression of NF-κB signaling pathway protein was detected by Western blot. Our results showed that soy isoflavones treatment significantly reduced the body weight, ovarian volume and weight, and improved estrous cycle in PCOS rats. H&E staining showed that the number of cystic dilated follicles and atretic follicles in ovarian tissue diminished, showing healthy follicles and corpus luteum. In addition, soy isoflavones treatment markedly decreased serum testosterone and luteinizing hormone (LH) levels, as well as oxidative stress levels and inflammation levels, and increased estradiol (E2) and follicle stimulating hormone (FSH) levels. At the same time, Soy isoflavones treatment inhibit the phosphorylation level of NF-κB p65 and increased the IκBα expression in ovarian tissues of PCOS rats. Overall, Soy isoflavones can improve ovarian morphology and hormone disorders in PCOS rats by inhibiting the activity of NF-κB pathway and enhancing anti-inflammatory and antioxidant capacity.

The Role of Aromatase Enzyme in Hormone Related Diseases and Plant-Based Aromatase Inhibitors as Therapeutic Regimens

Medicinal plants have a long history of use as food and remedy in traditional and modern societies, as well as have been used as herbal drugs and sources of novel bioactive compounds. They provide a wide array of chemical compounds, many of which can not be synthesized via current synthesis methods. Natural products may provide aromatase inhibitory activity through various pathways and may act clinically effective for treating pathologies associated with excessive aromatase secretion including breast, ovarian and endometrial cancers, endometriosis, uterine fibroid, benign prostatic hyperplasia (BPH), prostate cancer, infertility, and gynecomastia. Recent studies have shown that natural products with aromatase inhibitory activity, could also be good options against secondary recurrence of breast cancer by exhibiting chemopreventive effects. Therefore, screening for new plant-based aromatase inhibitors may provide novel leads for drug discovery and development, particularly with increased clinical efficacy and decreased side effects.

Manipulation of Dietary Intake on Changes in Circulating Testosterone Concentrations

Elevations in the circulating concentration of androgens are thought to have a positive effect on the anabolic processes leading to improved athletic performance. Anabolic-androgenic steroids have often been used by competitive athletes to augment this effect. Although there has been concerted effort on examining how manipulating training variables (e.g., intensity and volume of training) can influence the androgen response to exercise, there has been much less effort directed at understanding how changes in both macronutrient and micronutrient intake can impact the androgen response. Thus, the focus of this review is to examine the effect that manipulating energy and nutrient intake has on circulating concentrations of testosterone and what the potential mechanism is governing these changes.

In-vitro Cytotoxicity and Aromatase Inhibitory Activity of Flavonoids: Synthesis, Molecular Docking and In-silico ADME Prediction

BACKGROUND

Many natural and synthetic flavonoids have been studied and documented by inhibiting aromatase enzymes for their anti-cancer activity against breast carcinoma. The aromatase enzyme is a possible target for the estrogen's positive breast cancer receptor.

OBJECTIVE

Hence, a series of flavonoids have been synthesized and assessed for their in vitro cytotoxicity and aromatase inhibitory activity.

METHODS

39 flavonoids were synthesized and characterized by spectroscopic techniques, and their computational study was performed using the maestro version of the Schrodinger. In-silico ADME properties were checked by QikPro software. A total of 18 compounds were evaluated based on the docking score using cytotoxicity assay in human breast cancer cell line MCF-7.

RESULTS

Of the 18 compounds tested, 07 compounds, namely 2b, 8b, 14b, 15b, 19b, 24b, and 30b flavonoids were found to be more active with their IC₅₀ values of 20.73 μM, 1.636 μM, 16.08 μM, 22.02 μM, 15.75 μM, 0.345 μM and 16.08 μM, respectively, compared with the reference drug letrozole. The in-vitro aromatase inhibitory activity of six compounds 2b, 8b, 14b, 19b, 24b, and 30b was conducted using a fluorogenic assay kit. The values of IC₅₀ for compounds 2b and 24b were found to be 0.31 μM and 0.36 μM, respectively.

CONCLUSION

Therefore, it was concluded that compounds 2b and 24b had a potent inhibitory effect of aromatase compared with letrozole with an IC₅₀ value of 0.86 μM. At the same time, the other compounds 8b, 14b, 30b, and 19b were considered to have similar aromatase inhibitory activity. Hence, their essential aromatase inhibitory activities make them good lead candidates for developing potent inhibitors of aromatase.

Exploring the Biological Activity and Mechanism of Xenoestrogens and Phytoestrogens in Cancers: Emerging Methods and Concepts

Xenoestrogens and phytoestrogens are referred to as "foreign estrogens" that are produced outside of the human body and have been shown to exert estrogen-like activity. Xenoestrogens are synthetic industrial chemicals, whereas phytoestrogens are chemicals present in the plant. Considering that these environmental estrogen mimics potentially promote hormone-related cancers, an understanding of how they interact with estrogenic pathways in human cells is crucial to resolve their possible impacts in cancer. Here, we conducted an extensive literature evaluation on the origins of these chemicals, emerging research techniques, updated molecular mechanisms, and ongoing clinical studies of estrogen mimics in human cancers. In this review, we describe new applications of patient-derived xenograft (PDX) models and single-cell RNA sequencing (scRNA-seq) techniques in shaping the current knowledge. At the molecular and cellular levels, we provide comprehensive and up-to-date insights into the mechanism of xenoestrogens and phytoestrogens in modulating the hallmarks of cancer. At the systemic level, we bring the emerging concept of window of susceptibility (WOS) into focus. WOS is the critical timing during the female lifespan that includes the prenatal, pubertal, pregnancy, and menopausal transition periods, during which the mammary glands are more sensitive to environmental exposures. Lastly, we reviewed 18 clinical trials on the application of phytoestrogens in the prevention or treatment of different cancers, conducted from 2002 to the present, and provide evidence-based perspectives on the clinical applications of phytoestrogens in cancers. Further research with carefully thought-through concepts and advanced methods on environmental estrogens will help to improve understanding for the identification of environmental influences, as well as provide novel mechanisms to guide the development of prevention and therapeutic approaches for human cancers.

An updated review on the versatile role of chrysin in neurological diseases: Chemistry, pharmacology, and drug delivery approaches

Neurological diseases are responsible for a large number of morbidities and mortalities in the world. Flavonoids are phytochemicals that possess various health-promoting impacts. Chrysin, a natural flavonoid isolated from diverse fruits, vegetables, and even mushrooms, has several pharmacological activities comprising antioxidant, anti-inflammatory, antiapoptotic, anticancer, and neuroprotective effects. The current study was designed to review the relationship between chrysin administration and neurological complications by discussing the feasible mechanism and signaling pathways. Herein, we mentioned the sources, pharmacological properties, chemistry, and drug delivery systems associated with chrysin pharmacotherapy. The role of chrysin was discussed in depression, anxiety, neuroinflammation, Alzheimer's disease, Parkinson's disease, Huntington's disease, epilepsy, cerebral ischemia, spinal cord injury, neuropathy, Multiple Sclerosis, and Guillain-Barré Syndrome. The findings indicate that chrysin has protective effects against neurological conditions by modulating oxidative stress, inflammation, and apoptosis in animal models. However, more studies should be done to clear the neuroprotective effects of chrysin.

Emerging cellular and molecular mechanisms underlying anticancer indications of chrysin

Chrysin has been shown to exert several beneficial pharmacological activities. Chrysin has anti-cancer, anti-viral, anti-diabetic, neuroprotective, cardioprotective, hepatoprotective, and renoprotective as well as gastrointestinal, respiratory, reproductive, ocular, and skin protective effects through modulating signaling pathway involved in apoptosis, oxidative stress, and inflammation. In the current review, we discussed the emerging cellular and molecular mechanisms underlying therapeutic indications of chrysin in various cancers. Online databases comprising Scopus, PubMed, Embase, ProQuest, Science Direct, Web of Science, and the search engine Google Scholar were searched for available and eligible research articles. The search was conducted by using MeSH terms and keywords in title, abstract, and keywords. In conclusion, experimental studies indicated that chrysin could ameliorate cancers of the breast, gastrointestinal tract, liver and hepatocytes, bladder, male and female reproductive systems, choroid, respiratory tract, thyroid, skin, eye, brain, blood cells, leukemia, osteoblast, and lymph. However, more studies are needed to enhance the bioavailability of chrysin and evaluate this agent in clinical trial studies.

Iron Complexes of Flavonoids-Antioxidant Capacity and Beyond

Flavonoids are common plant natural products able to suppress ROS-related damage and alleviate oxidative stress. One of key mechanisms, involved in this phenomenon is chelation of transition metal ions. From a physiological perspective, iron is the most significant transition metal, because of its abundance in living organisms and ubiquitous involvement in redox processes. The chemical, pharmaceutical, and biological properties of flavonoids can be significantly affected by their interaction with transition metal ions, mainly iron. In this review, we explain the interaction of various flavonoid structures with Fe(II) and Fe(III) ions and critically discuss the influence of chelated ions on the flavonoid biochemical properties. In addition, specific biological effects of their iron metallocomplexes, such as the inhibition of iron-containing enzymes, have been included in this review.

Flavonoids in the Treatment of Diabetes: Clinical Outcomes and Mechanism to Ameliorate Blood Glucose Levels

BACKGROUND

For thousands of years, natural food products have been used as a medicine for treating diseases that affect the human body, including diabetes mellitus (DM). Lately, several investigations have been performed on the flavonoid derivatives of plant origin, and their biological activity has been extensively studied.

METHODS

Given our need to know more mechanisms for treating DM, we performed a thorough research review on treating diabetes mellitus based on flavonoids, their therapeutic potential, and biological action.

RESULTS

Flavonoids reduce complications in addition to their vital role as effective supplements for preventing diabetes mellitus by regulating glucose metabolism, lipid profile, liver enzyme activity, a protein kinase inhibitor, PPAR, and AMPK with NF-κB.

CONCLUSION

The articles that we reviewed showed the positive role of flavonoids, which in a certain way reduce diabetes, but their side effects still need to be studied further.This review is focused on describing the different types of dietary flavonoids along with their mechanisms of reducing blood glucose and enhancing insulin sensitivity, as well as their side effects.

Engagement of phytoestrogens in breast cancer suppression: Structural classification and mechanistic approach

Cancer is the world's devastating disease, and breast cancer is the most common reason for the death of women worldwide. Many synthetic drugs and medications are provided with their beneficial actions, but all of these have side effects and resistance problems. Natural remedies are coming forward to overcome the disadvantages of synthetic drugs. Among the natural categories, phytoestrogens having a structural similarity of mammalian oestradiol proves its benefit with various mechanisms not only in the treatment of breast cancer but even to prevent the occurrence of postmenopausal symptoms. Phytoestrogens are plant-derived compounds that were utilized in ancient medications and traditional knowledge for its sex hormone properties. Phytoestrogens exert pleiotropic effects on cellular signalling and show effects on estrogen-dependent diseases. However, because of activation/inhibition of steroid hormonal receptor ER-α or ER-β, these compounds induce or inhibit steroid hormonal (estrogen) action and, therefore, have the potential to disrupt hormone (estrogen) signalling pathway. In this review, we have discussed and summarize the effect of certain phytoestrogens and their possible mechanisms that can substantiate advantageous benefits for the treatment of post-menopausal symptoms as well as for breast cancer.

Chrysoeriol Prevents TNFα-Induced CYP19 Gene Expression via EGR-1 Downregulation in MCF7 Breast Cancer Cells

Estrogen overproduction is closely associated with the development of estrogen receptor-positive breast cancer. Aromatase, encoded by the cytochrome P450 19 (CYP19) gene, regulates estrogen biosynthesis. This study aimed to identify active flavones that inhibit CYP19 expression and to explore the underlying mechanisms. CYP19 expression was evaluated using reverse transcription PCR, quantitative real-time PCR, and immunoblot analysis. The role of transcription factor early growth response gene 1 (EGR-1) in CYP19 expression was assessed using the short-hairpin RNA (shRNA)-mediated knockdown of EGR-1 expression in estrogen receptor-positive MCF-7 breast cancer cells. We screened 39 flavonoids containing 26 flavones and 13 flavanones using the EGR1 promoter reporter activity assay and observed that chrysoeriol exerted the highest inhibitory activity on tumor necrosis factor alpha (TNFα)-induced EGR-1 expression. We further characterized and demonstrated that chrysoeriol inhibits TNFα-induced CYP19 expression through inhibition of extracellular signal-regulated kinase 1/2 (ERK1/2)-mediated EGR-1 expression. Chrysoeriol may be beneficial as a dietary supplement for the prevention of estrogen receptor-positive breast cancer, or as a chemotherapeutic adjuvant in the treatment of this condition.

Sex Differences in the Inflammatory Consequences of Stress: Implications for Pharmacotherapy

Women are at significantly greater risk of developing stress-related disorders such as depression. The increased risk begins during puberty and continues throughout life until menopause, suggesting a role for ovarian hormones in this increased susceptibility. Importantly, inflammation has been gaining momentum in its role in the pathogenesis of depression. Herein, clinical and preclinical studies have been reviewed to better understand how sex differences within the immune system may contribute to exaggerated risk of depression in females. First, studies that investigate the ability of psychologic stress episodes to engage the inflammatory systems both in the brain and periphery are reviewed with a special focus on sex-specific effects. Moreover, studies are discussed that identify whether imbalanced inflammatory milieu contributes to the development of depression in males versus females and whether these effects are regulated by estradiol. Importantly, we propose a locus coeruleus-norepinephrine-cytokine circuit as a conduit through which stress could increase stress susceptibly in females. Finally, the anti-inflammatory capacity of traditional and nontraditional antidepressants is investigated, with the goal of providing a better understanding of pharmacotherapeutics to enhance strategies to personalize antidepressant treatments between the sexes. The studies reviewed herein strongly support the need for further studies to elucidate whether females are especially sensitive to anti-inflammatory compounds as adjuvants to traditional therapies. SIGNIFICANCE STATEMENT: Women have hve an increased risk of developing stress-related disorders such as depression. In this review, literature from clinical and preclinical studies are integrated to define sex differences in stress-induced inflammatory responses as a potential source for the etiology of sex differences in depressive disorders. Moreover, the anti-inflammatory capacity of traditional and nontraditional antidepressants is reviewed to inform on potential pharmacotherapeutic strategies to personalize antidepressant therapy in a sex-dependent manner.

Bioactive Compounds and Metabolites from Grapes and Red Wine in Breast Cancer Chemoprevention and Therapy

Phytochemicals and their metabolites are not considered essential nutrients in humans, although an increasing number of well-conducted studies are linking their higher intake with a lower incidence of non-communicable diseases, including cancer. This review summarizes the current findings concerning the molecular mechanisms of bioactive compounds from grapes and red wine and their metabolites on breast cancer—the most commonly occurring cancer in women—chemoprevention and treatment. Flavonoid compounds like flavonols, monomeric catechins, proanthocyanidins, anthocyanins, anthocyanidins and non-flavonoid phenolic compounds, such as resveratrol, as well as their metabolites, are discussed with respect to structure and metabolism/bioavailability. In addition, a broad discussion regarding in vitro, in vivo and clinical trials about the chemoprevention and therapy using these molecules is presented.

Association between dietary intake and risk of ovarian cancer: a systematic review and meta-analysis

PURPOSE

It is unclear how dietary intake influences the ovarian cancer. The present paper sets out to systematically review and meta-analyze research on dietary intake to identify cases having high- or low-risk ovarian cancer.

METHODS

Scopus, PubMed, and Wiley Online Libraries were searched up to the date November 24, 2019. Two reviewers were requested to independently extract study characteristics and to assess the bias and applicability risks with reference to the study inclusion criteria. Meta-analyses were performed to specify the relationship between dietary intake and the risk of ovarian cancer identifying 97 cohort studies.

RESULTS

No significant association was found between dietary intake and risk of ovarian cancer. The results of subgroup analyses indicated that green leafy vegetables (RR = 0.91, 95%, 0.85-0.98), allium vegetables (RR = 0.79, 95% CI 0.64-0.96), fiber (RR = 0.89, 95% CI 0.81-0.98), flavonoids (RR = 0.83, 95% CI 0.78-0.89) and green tea (RR = 0.61, 95% CI 0.49-0.76) intake could significantly reduce ovarian cancer risk. Total fat (RR = 1.10, 95% CI 1.02-1.18), saturated fat (RR = 1.11, 95% CI 1.01-1.22), saturated fatty acid (RR = 1.19, 95% CI 1.04-1.36), cholesterol (RR = 1.13, 95% CI 1.04-1.22) and retinol (RR = 1.14, 95% CI 1.00-1.30) intake could significantly increase ovarian cancer risk. In addition, acrylamide, nitrate, water disinfectants and polychlorinated biphenyls were significantly associated with an increased risk of ovarian cancer.

CONCLUSION

These results could support recommendations to green leafy vegetables, allium vegetables, fiber, flavonoids and green tea intake for ovarian cancer prevention.

Modulation of glutamate levels and Na+,K+-ATPase activity contributes to the chrysin memory recovery in hypothyroidism mice

Abnormalities in the thyroid hormones, like in hypothyroidism, are closely related to dementia and Alzheimer's disease demonstrating the main symptom of these disorders: memory deficit. In this study we evaluated the effect of chrysin on deficit spatial and aversive memories and the contribution of glutamatergic, cholinergic pathways and Na⁺, K⁺-ATPase activity on hippocampus and prefrontal cortex in hypothyroid adult female mice C57BL/6. Hypothyroidism was induced by the continuous exposure to 0.1% methimazole (MTZ) in drinking water for 31 days. The exposure to MTZ was associated to low plasma levels of thyroid hormones (TH) compared to the control group on the 32nd. Subsequently, euthyroid and MTZ-induced hypothyroid mice received (intragastrically) either vehicle or chrysin (20 mg/kg) once a day for 28 consecutive days. After treatments mice performed the following behavioral assessments: open-field test (OFT), morris water maze (MWM) and passive avoidance test. Additionally, plasma TH levels were measured again, as well as glutamate levels, Na⁺,K⁺-ATPase and acetylcholinesterase (AChE) activities were analyzed in the hippocampus and prefrontal cortex of mice. Mice with hypothyroidism showed a deficit of spatial and aversive memory and chrysin treatment reversed these deficits. It also reduced the levels of glutamate and decreased Na⁺,K⁺-ATPase activity in both cerebral structures in the hypothyroid mice compared with the euthyroid ones, with the exception of glutamate in the hippocampus, which was a partial reversal. AChE activity was not altered by treatments. Together, our results demonstrate that chrysin normalized hippocampal glutamate levels and Na⁺,K⁺-ATPase activity, which could be involved in the reversal of memory deficit.

Nutrigenomics-Associated Impacts of Nutrients on Genes and Enzymes With Special Consideration of Aromatase

Interactions are occurring in the course of liberation, absorption, distribution, metabolism, and excretion of active ingredients, or at the target receptors. They are causing therapy failures and undesirable events. Forty-seven of fifty-seven human hepatic isoenzymes are specific and relevant in hormone and vitamin metabolism and biosynthesis. Aromatase (syn. CYP19A1) is one of the specific CYP450 isoenzymes so far not elucidated in detail. As aromatase-inhibiting phytochemicals are currently recommended for breast cancer prevention and as add-on accompanying aromatase-inhibitor pharmacotherapy, it was the aim of this literature review to assess whether a common interpretation on genetic and -omics basis could be found. Articles retrieved showed that traditional antioxidation diet is one of the most approved explanations of inhibition of aromatase by phytonutrients of flavonoid derivatives. Flavonoids compete for the oxygen provided by the heme moiety of aromatase in the course of aromatase-catalyzed conversion of steroid precursors to estrogens. Flavonoids are therefore promoted for breast cancer prevention. A further explanation of flavonoids' mechanism of action proposed was related to enzymatic histone deacetylation. By keeping DNA-structure wide through a high acetylation degree, acetylated histones favor transcription and replication. This mechanism corresponds to a procedure of switching genes on. Inhibiting acetylation and therefore switching genes off might be an important regulation of repressing cancer genes. Aromatase expression depends on the genotype and phenotype of a person. Aromatase itself depends on the expression of the heme moiety encoded in the genotype. Biosynthesis of porphyrins in turn depends on the substrates succinate and glycine, as well as on a series of further enzymes, with ALA synthetase as the rate-limiting step. The effect of the heme moiety as prosthetic group of aromatase further depends on the absorption of iron as a function of pH and redox state. To assess the function of aromatase precisely, multiple underlying biochemical pathways need to be evaluated. As a conclusion, the genetic regulation of metabolism is a complex procedure affecting multiple pathways. To understand a metabolic step, multiple underlying individually performing reactions need to be considered if personalized (nutritional) medicine should bring an advantage for a patient. Nutrition sciences need to consider the genome of an individual to truly find answers to nutrition-derived non-communicable diseases. With current GWAS (genome-wide association study) approaches, inherited errors of metabolism are identified and ideally treated effectively. It is much more difficult to get a precise genetic profile for non-communicable diseases stemming from multifactorial causes. Polygenic risks evaluation is feasible but diagnostic tools are not yet available in a desired extent. Neither flavonoid researchers nor providers of genetic testing kits are going into the details needed for a truly personalized nutritional medicine. The next step with profiling the exome and then the whole genome is on the threshold of becoming routine diagnosis and of bringing the desired details.

Inhibitory effect of chrysin on estrogen biosynthesis by suppression of enzyme aromatase (CYP19): A systematic review

The cytochrome P450 enzyme functions as the rate-limiting enzyme in changing androgens to estrogens. Inhibition of aromatase is one of the significant objectives of treatment of hormone-dependent diseases such as breast cancer, especially in post-menopausal women. Natural compounds like chrysin, as a flavor that has a high concentration in honey and propolis, are rich sources of them can be useful in inhibiting aromatase for chemoprevention following treatment or in women at risk of acquiring breast cancer. This study intended to summarize the existing evidence on the effect of chrysin on aromatase activity. We systematically searched Science Direct, PubMed and Google Scholar and hand searched the reference lists of identified relevant articles, up to 5 February, 2019. Articles with English abstracts that reported the effect of chrysin on aromatase inhibition and without publication date restriction were investigated. Twenty relevant articles were chosen from a total of 1721 articles. Only one study was performed on humans and two studies were assayed on rats, while other studies were evaluated in vitro. All the studies except one showed that chrysin had the potency of aromatase inhibition; however, only one study performed on endometrial stromal cells showed that chrysin and naringenin did not indicate aromatase inhibitory properties. Various assay methods and experimental conditions were the important aspects leading to different results between the studies. Chrysin has potency in inhibition of the aromatase enzyme and thus can be useful in preventing and treating the hormone-dependent breast cancer and as an adjuvant therapy for estrogen-dependent diseases.

Development of a prioritization method for chemical-mediated effects on steroidogenesis using an integrated statistical analysis of high-throughput H295R data

Synthesis of 11 steroid hormones in human adrenocortical carcinoma cells (H295R) was measured in a high-throughput steroidogenesis assay (HT-H295R) for 656 chemicals in concentration-response as part of the US Environmental Protection Agency's ToxCast program. This work extends previous analysis of the HT-H295R dataset and model by examining the utility of a novel prioritization metric based on the Mahalanobis distance that reduced these 11-dimensional data to 1-dimension via calculation of a mean Mahalanobis distance (mMd) at each chemical concentration screened for all hormone measures available. Herein, we evaluated the robustness of mMd values, and demonstrate that covariance and variance of the hormones measured appear independent of the chemicals screened and are inherent to the assay; the Type I error rate of the mMd method is less than 1%; and, absolute fold changes (up or down) of 1.5 to 2-fold have sufficient power for statistical significance. As a case study, we examined hormone responses for aromatase inhibitors in the HT-H295R assay and found high concordance with other ToxCast assays for known aromatase inhibitors. Finally, we used mMd and other ToxCast cytotoxicity data to demonstrate prioritization of the most selective and active chemicals as candidates for further in vitro or in silico screening.

Short-term exposure to chrysin promotes proliferative responses in the ventral male prostate and female prostate of adult gerbils

Chrysin (5,7-dihydroxyflavone) is a bioactive compound found in different fruits, vegetables, honey and propolis. This flavone has been suggested for the treatment of reproductive dysfunction, mainly because of its antioxidant and hormonal properties. However, the effects of this polyphenol on the prostate are still poorly understood. The purpose of this study was to evaluate the effects of short-term chrysin exposure on the ventral male and female prostates of adult gerbils. To evaluate the androgenic potential of chrysin, gerbils were also exposed to testosterone. Male and female gerbils were exposed to chrysin (50 mg/kg/day, orally) or testosterone cypionate (1 mg/kg/week, subcutaneously) for 3, 7 and 21 days. Prostates were dissected for morphological, stereological and immunohistochemical analyses. Serum levels of testosterone and 17β-estradiol were measured by ELISA. Serum testosterone levels were not increased by chrysin supplementation in males or females. However, only females treated with chrysin for 21 days showed an increase in estradiol levels. Increased androgen receptor immunoreactivity, higher proliferation rates and glandular hyperplasia were observed in male and female prostates for all chrysin treatment times. Additionally, increased oestrogen receptor alpha immunoreactivity was observed in all chrysin-treated females. Although chrysin and testosterone promoted similar morphological changes in the gerbil prostate, chrysin supplementation was less deleterious to prostate health, since it resulted in lower incidence of hyperplasia and an absence of neoplastic foci.

Interaction of Chrysin and Its Main Conjugated Metabolites Chrysin-7-Sulfate and Chrysin-7-Glucuronide with Serum Albumin

Chrysin (5,7-dihydroxyflavone) is a flavonoid aglycone, which is found in nature and in several dietary supplements. During the biotransformation of chrysin, its conjugated metabolites chrysin-7-sulfate (C7S) and chrysin-7-glucuronide (C7G) are formed. Despite the fact that these conjugates appear in the circulation at much higher concentrations than chrysin, their interactions with serum albumin have not been reported. In this study, the complex formation of chrysin, C7S, and C7G with human (HSA) and bovine (BSA) serum albumins was investigated employing fluorescence spectroscopic, ultrafiltration, and modeling studies. Our major observations/conclusions are as follows: (1) Compared to chrysin, C7S binds with a threefold higher affinity to HSA, while C7G binds with a threefold lower affinity; (2) the albumin-binding of chrysin, C7S, and C7G did not show any large species differences regarding HSA and BSA; (3) tested flavonoids likely occupy Sudlow’s Site I in HSA; (4) C7S causes significant displacement of Sudlow’s Site I ligands, exerting an even stronger displacing ability than the parent compound chrysin. Considering the above-listed observations, the high intake of chrysin (e.g., through the consumption of dietary supplements with high chrysin contents) may interfere with the albumin-binding of several drugs, mainly due to the strong interaction of C7S with HSA.

Chemoprevention of LA7-Induced Mammary Tumor Growth by SM6Met, a Well-Characterized Cyclopia Extract

Breast cancer (BC) is the leading cause of cancer-related deaths in women. Chemoprevention of BC by using plant extracts is gaining attention. SM6Met, a well-characterized extract of Cyclopia subternata with reported selective estrogen receptor subtype activity, has shown tumor suppressive effects in a chemically induced BC model in rats, which is known to be estrogen responsive. However, there is no information on the estrogen sensitivity of the relatively new orthotopic model of LA7 cell-induced mammary tumors. In the present study, the potential chemopreventative and side-effect profile of SM6Met on LA7 cell-induced tumor growth was evaluated, as was the effects of 17β-estradiol and standard-of-care (SOC) endocrine therapies, such as tamoxifen (TAM), letrozole (LET), and fulvestrant (FUL). Tumor growth was observed in the tumor-vehicle control group until day 10 post tumor induction, which declined afterward on days 12-14. SM6Met suppressed tumor growth to the same extent as TAM, while LET, but not FUL, also showed substantial anti-tumor effects. Short-term 17β-estradiol treatment reduced tumor volume on days prior to day 10, whereas tumor promoting effects were observed during long-term treatment, which was especially evident at later time points. Marked elevation in serum markers of liver injury, which was further supported by histological evaluation, was observed in the vehicle-treated tumor control, TAM, LET, and long-term 17β-estradiol treatment groups. Alterations in the lipid profiles were also observed in the 17β-estradiol treatment groups. In contrast, SM6Met did not augment the increase in serum levels of liver injury biomarkers caused by tumor induction and no effect was observed on lipid profiles. In summary, the results from the current study demonstrate the chemopreventative effect of SM6Met on mammary tumor growth, which was comparable to that of TAM, without eliciting the negative side-effects observed with this SOC endocrine therapy. Furthermore, the results of this study also showed some responsiveness of LA7-induced tumors to estrogen and SOC endocrine therapies. Thus, this model may be useful in evaluating potential endocrine therapies for hormone responsive BC.

Engineering substrate promiscuity in 2,4-dichlorophenol hydroxylase by in silico design

2,4-Dichlorophenol hydroxylase (2,4-DCP hydroxylase) is a key enzyme in the degradation of 2,4-dichlorophenoxyacetic acid in the hydroxylation step in many bacteria. Our previous study demonstrated that a 2,4-DCP hydroxylase (TfdB-JLU) exhibits broad substrate specificity for chlorophenols (CPs) and their homologues. In this study, TfdB-JLU has been engineered by rational design to further broaden its substrate scope towards CPs. We dissect the architectures of enzymes from oxidoreductase families to discover their underlying structural sources of substrate promiscuity. A homology model of TfdB-JLU has been built and docking experiments of this homology model with its natural substrate 2,4-DCP reveal that the phenyl rings of 2,4-DCP form strong interactions with residues His47, Ile48, Trp222, Pro316, and Phe424. These residues are found to be important for substrate binding in the active site. Then, the site-directed mutagenesis strategy has been applied for redesigning substrate promiscuity in TfdB-JLU. The TfdB-JLU-P316Q variant obtained shows a significant enhancement of activity (up to 3.4-fold) toward 10 CP congeners compared to wild-type TfdB-JLU. Interestingly, the active improvements of TfdB-JLU-P316Q toward CP congeners show significant difference, especially for active improvements of positional congeners such as 3-CP (1.1-fold) compared to 4-CP (3.0-fold), as well as 2,3-DCP (1.2-fold) compared to 2,5-DCP (3.4-fold). Structural analysis results indicate that the improvement in substrate promiscuity of the variant enzyme compared to the wild-type enzyme is possibly due to the increase of non-bonding interaction. The results suggest that exploiting enzyme-substrate promiscuity is promising, which would provide a starting point for designing and engineering novel biological catalysts for pollution removal.

Resveratrol supports and alpha-naphthoflavone disrupts growth of human ovarian follicles in an in vitro tissue culture model

Infertility is a global health problem with an estimated incidence of 15%. Exposure to chemicals is a potential causal factor, and there is a lack of studies examining the effects on female germ cells. Here, we have studied the impact of different aryl hydrocarbon receptor (AHR) modulators on human ovarian follicles using a human ovarian tissue culture model. Expression of AHR was analyzed in tissue samples, and effects of the selected ligands resveratrol (RSVL), 6-formylindolo(3,2-b)carbazole (FICZ), and alpha-naphthoflavone (aNF) on AHR transactivation studied in a granulosa cell tumor line. Cortical human ovarian tissue containing preantral follicles was exposed to the ligands or vehicle (dimethylsulfoxide, DMSO) for seven days in vitro. Follicle growth was assessed by counting and measuring follicles from serial tissue sections, cell death quantified using in situ Terminal deoxynucleotidyl transferase dUTP Nick-End Labeling (TUNEL) assay, and steroid hormone production measured using a newly developed ultra-performance liquid chromatography method. AHR was expressed in all donated ovarian tissue samples. FICZ induced AHR transactivation in the granulosa cell line while aNF antagonised it. Compared to DMSO control, FICZ had no effect on follicles in culture, RSVL increased the proportion of growing follicles, and aNF increased cell death, disrupted growth of secondary follicles, increased testosterone, and reduced estradiol levels. We conclude that RSVL supports and aNF disrupts growth of human ovarian follicles in culture. We further conclude that the human ovarian tissue culture model is suitable for studying effects of chemicals on follicular biology.

Sex differences in brain-derived neurotrophic factor signaling and functions

Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin family that plays a critical role in numerous neuronal activities. Recent studies have indicated that some functions or action mechanisms of BDNF vary in a sex-dependent manner. In particular, BDNF content in some brain parts and the tendency to develop BDNF deficiency-related diseases such as depression are greater in female animals. With the support of relevant studies, it has been suggested that sex hormones or steroids can modulate the activities of BDNF, which may account for its functional discrepancy in different sexes. Indeed, the cross-talk between BDNF and sex steroids has been detected for decades, and some sex steroids, such as estrogen, have a positive regulatory effect on BDNF expression and signaling. Thus, the sex of animal models that are used in studying the functions of BDNF is critical. This Mini-Review summarizes our current findings on the differences in expression, signaling, and functions of BDNF between sexes. We also discuss the potential mechanisms for mediating these differential responses, with a specific emphasis on sex steroids. By presenting and discussing these findings, we seek to encourage researchers to take sex influences into consideration when designing experiments, interpreting results, and drawing conclusions. © 2016 Wiley Periodicals, Inc.

The role of soybean extracts and isoflavones in hormone-dependent breast cancer: aromatase activity and biological effects

Estrogen receptor-positive (ER+) breast cancer is the most common cause of cancer death in women worldwide. Nowadays, the relationship between soya diet and breast cancer is controversial due to the unknown role of its isoflavones, genistein (G) and daidzein (D). In this work, we investigated not only the anti-tumor properties of a soybean extract (NBSE) but also whether the biotransformation of extract (BSE) by the fungus Aspergillus awamori increased its effectiveness. The BSE showed a stronger anti-aromatase activity and anti-proliferative efficacy in ER+ aromatase-overexpressing breast cancer cells. D and G were weak aromatase inhibitors, but inhibited cancer cell growth, being G the isoflavone that contributed to the BSE-induced effects. This work demonstrated that the biotransformation increased the anti-aromatase activity and the anti-tumoral efficacy of soybean extract in breast cancer cells. Moreover, it elucidated the potential use of soya in the prevention and/or treatment of ER+ breast cancer.

Protective Effects of Chrysin Against Drugs and Toxic Agents

Issues:

Polyphenolic compounds, especially flavonoids, are known as the most common chemical class of phytochemicals, which possess a multiple range of health-promoting effects. Flavonoids are ubiquitous in nature. They are also present in food, providing an essential link between diet and prevention of several diseases.

Approach:

Chrysin (CH), a natural flavonoid, was commonly found in propolis and honey and traditionally used in herbal medicine. A growing body of scientific evidence has shown that CH possesses protective effects against toxic agents in various animal tissues, including brain, heart, liver, kidney, and lung.

Key Findings:

This study found that CH may be effective in disease management induced by toxic agents. However, due to the lack of information on human, further studies are needed to determine the efficacy of CH as an antidote agent in human.

Conclusion:

The present article aimed to critically review the available literature data regarding the protective effects of CH against toxic agent–induced toxicities as well as its possible mechanisms.

Synthesis, characterization and biological evaluation of ruthenium flavanol complexes against breast cancer

Four Ru(II) DMSO complexes (M1R-M4R) having substituted flavones viz. 3-Hydroxy-2-(4-methoxyphenyl)-4H-chromen-4-one (HL1), 3-Hydroxy-2-(4-nitrophenyl)-4H-chromen-4-one (HL2), 3-Hydroxy-2-(4-dimethylaminophenyl)-4H-chromen-4-one (HL3) and 3-Hydroxy-2-(4-chlorophenyl)-4H-chromen-4-one (HL4) were synthesized and characterized by elemental analysis, IR, UV-Vis, ¹H NMR spectroscopies and ESI-MS. The molecular structures of the complexes were investigated by integrated spectroscopic and computational techniques (DFT). Both ligands as well as their complexes were screened for anticancer activities against breast cancer cell lines MCF-7. Cytotoxicity was assayed by MTT [3-(4, 5-dimethyl thiazol-2-yl)-2, 5-diphenyl tetrazolium bromide] assay. All ligands and their complexes exhibited significant cytotoxic potential of 5-40μM concentration at incubation period of 24h. The cell cytotoxicity increased significantly in a concentration-dependent manner. In this series of compounds, HL2 (IC₅₀ 17.2μM) and its complex M2R (IC₅₀ 16μM) induced the highest cytotoxicity.

Aromatase inhibitory activity of 1,4-naphthoquinone derivatives and QSAR study

A series of 2-amino(chloro)-3-chloro-1,4-naphthoquinone derivatives (1-11) were investigated for their aromatase inhibitory activities. 1,4-Naphthoquinones 1 and 4 were found to be the most potent compounds affording IC₅₀ values 5.2 times lower than the reference drug, ketoconazole. A quantitative structure-activity relationship (QSAR) model provided good predictive performance (R²_CV = 0.9783 and RMSE_CV = 0.0748) and indicated mass (Mor04m and H8m), electronegativity (Mor08e), van der Waals volume (G1v) and structural information content index (SIC2) descriptors as key descriptors governing the activity. To investigate the effects of structural modifications on aromatase inhibitory activity, the model was employed to predict the activities of an additional set of 39 structurally modified compounds constructed in silico. The prediction suggested that the 2,3-disubstitution of 1,4-naphthoquinone ring with halogen atoms (i.e., Br, I and F) is the most effective modification for potent activity (1a, 1b and 1c). Importantly, compound 1b was predicted to be more potent than its parent compound 1 (11.90-fold) and the reference drug, letrozole (1.03-fold). The study suggests the 1,4-naphthoquinone derivatives as promising compounds to be further developed as a novel class of aromatase inhibitors.

Chemopreventive Agents and Inhibitors of Cancer Hallmarks: May Citrus Offer New Perspectives?

Fruits and vegetables have long been recognized as potentially important in the prevention of cancer risk. Thus, scientific interest in nutrition and cancer has grown over time, as shown by increasing number of experimental studies about the relationship between diet and cancer development. This review attempts to provide an insight into the anti-cancer effects of Citrus fruits, with a focus on their bioactive compounds, elucidating the main cellular and molecular mechanisms through which they may protect against cancer. Scientific literature was selected for this review with the aim of collecting the relevant experimental evidence for the anti-cancer effects of Citrus fruits and their flavonoids. The findings discussed in this review strongly support their potential as anti-cancer agents, and may represent a scientific basis to develop nutraceuticals, food supplements, or complementary and alternative drugs in a context of a multi-target pharmacological strategy in the oncology.

The Anti-Cancer Effect of Polyphenols against Breast Cancer and Cancer Stem Cells: Molecular Mechanisms

The high incidence of breast cancer in developed and developing countries, and its correlation to cancer-related deaths, has prompted concerned scientists to discover novel alternatives to deal with this challenge. In this review, we will provide a brief overview of polyphenol structures and classifications, as well as on the carcinogenic process. The biology of breast cancer cells will also be discussed. The molecular mechanisms involved in the anti-cancer activities of numerous polyphenols, against a wide range of breast cancer cells, in vitro and in vivo, will be explained in detail. The interplay between autophagy and apoptosis in the anti-cancer activity of polyphenols will also be highlighted. In addition, the potential of polyphenols to target cancer stem cells (CSCs) via various mechanisms will be explained. Recently, the use of natural products as chemotherapeutics and chemopreventive drugs to overcome the side effects and resistance that arise from using chemical-based agents has garnered the attention of the scientific community. Polyphenol research is considered a promising field in the treatment and prevention of breast cancer.

Dietary supplementation of yucca (Yucca schidigera) affects ovine ovarian functions

Yucca (Yucca schidigera) is a popular medicinal plant due to its many positive effects on animal and human physiology, including their reproductive systems. To examine the effect of supplemental yucca feeding on sheep reproduction, including ovarian functions and their hormonal regulators, ewes were fed (or not fed, control) yucca powder (1.5 g/head/day, 30 days). Macromorphometric indexes of the oviduct, ovary, and ovarian folliculogenesis were measured. Reproductive hormone levels in the blood were measured using a radioimmunoassay. Granulosa cells were aspirated from the ovary, and their proliferation and apoptosis were detected using immunocytochemistry. To assess secretory activity and its response to gonadotropin, ovarian fragments of treated and control ewes were cultured with and without follicle-stimulating hormone (FSH; 0, 0.1, 1, 10, or 100 IU/mL), and the release of reproductive hormones into the culture medium was evaluated. Finally, to examine the direct action of yucca on the ovary, ovarian fragments from control ewes were cultured with and without yucca extract (1, 10, or 100 μg/mL), and the release of reproductive hormones was measured. Yucca supplementation significantly decreased the size of small antral follicles (2 to <5 mm in diameter), increased accumulation of the apoptosis marker bax, and decreased serum progesterone (P4) and estradiol (E2) levels. It inhibited the release of P4 (but not other hormones), to prevent the stimulatory action of FSH on P4 output and promoted insulin-like growth factor I (IGF-I) release by fragments cultured with FSH. However, yucca supplementation did not affect the size of larger follicles and number of follicles, volume and weight of ovaries, length and weight of oviducts, caspase 3 accumulation, cell proliferation, testosterone (T) or IGF-I serum levels, or T or E2 release by cultured ovarian fragments and their response to FSH. Yucca addition to culture medium inhibited P4 and IGF-I, but not T or E2 release at the lowest (1 μg/mL) dose, and stimulated P4, but not T, E2, or IGF-I release at the highest (100 μg/mL) dose. These data suggest that yucca supplementation can reduce small antral ovarian follicle development possibly via the stimulation of apoptosis of their granulosa cells, suppression of ovarian P4 and E2 release, and alteration of ovarian IGF-I output and ovarian response to gonadotropin. Thus, yucca can directly affect P4 and IGF-I release by ovine ovarian cells.