Genistein, a dietary soy isoflavone, exerts antidepressant-like effects in mice: Involvement of serotonergic system

Flavonoids, gut microbiota, and host lipid metabolism

Flavonoids are widely distributed in nature and have a variety of beneficial biological effects, including antioxidant, anti-inflammatory, and anti-obesity effects. All of these are related to gut microbiota, and flavonoids also serve as a bridge between the host and gut microbiota. Flavonoids are commonly used to modify the composition of the gut microbiota by promoting or inhibiting specific microbial species within the gut, as well as modifying their metabolites. In turn, the gut microbiota extensively metabolizes flavonoids. Hence, this reciprocal relationship between flavonoids and the gut microbiota may play a crucial role in maintaining the balance and functionality of the metabolism system. In this review, we mainly highlighted the biological effects of antioxidant, anti-inflammatory and antiobesity, and discussed the interaction between flavonoids, gut microbiota and lipid metabolism, and elaborated the potential mechanisms on host lipid metabolism.

Glycitein prevents reserpine-induced depression and associated comorbidities in mice: modulation of lipid peroxidation and TNF-α levels

Depression is a debilitating mood disorder affecting millions worldwide and continues to pose a significant global health burden. Due to the multifaceted nature of depression, the current treatment regimens are not up to mark in terms of their multitargeting potential and least side effect profile. Molecules within the isoflavone class demonstrate promising potential in alleviating depression and associated conditions, offering a multifaceted approach to manage mental health concerns. Therefore, the current study was designed to explore the potential of glycitein, an isoflavone in managing reserpine-induced depression and associated comorbidities in mice. Reserpine (0.5 mg/kg; i.p.) administration for the first 3 days induced depression and associated comorbidities as evidenced by increased immobility time in forced swim test (FST) and tail suspension test (TST), along with reduced locomotor activity in the open field test (OFT) and increased latency to reach the platform in the Morris water maze (MWM) test. Reserpine treatment also upregulated and downregulated the brain thiobarbituric acid reactive substance (TBARS) and glutathione (GSH) levels, respectively. Furthermore, reserpine administration also uplifted the level of TNF-α in the serum samples. Glycitein (3 mg/kg and 6 mg/kg; p.o.) treatment for 5 days prevented the depressive effect of reserpine. It also improved the spatial memory at both dose levels. Moreover, in biochemical analysis, glycitein also reduced the brain TBARS and serum tumor necrosis factor-alpha (TNF-α) levels. Whereas, no significant effect was seen on the brain GSH level. Glycitein (6 mg/kg) was found to be more effective than the 3 mg/kg dose of glycitein. Overall results delineate that glycitein has the potential to manage depression and impaired memory by inhibiting lipid peroxidation and inflammatory stress.

Investigating the Role of 17β-Estradiol on the Serotonergic System, Targeting Soy Isoflavones as a Strategy to Reduce Menopausal Depression: A Mechanistic Review

Low serotonin is one factor implicated in the development of depression. 17β-estradiol (E2) has been shown to modulate gene expression regulating the neurotransmission of serotonin. Sex hormone levels fluctuate dramatically during the menopausal transition, coinciding with a 14-fold increased risk of depression. This review aimed to examine the effect of soy isoflavones to support decreased and variable E2 levels before and after menopause, linked to an investigation of the pathophysiological mechanisms underlying the protective influence of E2 on the serotonin pathway. The overall aim of this review is to assess the potential of soy isoflavones to reduce depression in middle-aged women. A systematic literature search was performed in three stages. 1,421 papers were screened for relevance to the research aims and objectives. 63 papers were selected based on pre-defined inclusion/exclusion criteria (13 reviews, 24 mechanistic and 26 intervention studies) and critically appraised. Available research supported the hypotheses that E2 increases serotonin synthesis and availability through stimulation of tryptophan hydroxylase-2 (TPH-2) and decreased degradation by monoamine oxidase-A (MAO-A). There was less scientific agreement on the effects of E2 on serotonin transporter (SERT) and serotonin receptors 1 A and 2 A. Studies varied widely on the effectiveness of soy isoflavones in reducing depressive symptoms in (peri)menopausal women. Animal and human studies acknowledge women's increased risk of depression linked to fluctuating E2 rather than absolute levels. However, mechanisms linking E2 variability with depression remain an underrepresented area of research. Study limitations and heterogeneity may contribute to varying results for soy isoflavones and some effects of E2 on the serotonin pathway.

Mechanistic interplay of different mediators involved in mediating the anti-depressant effect of isoflavones

Depression is one of the most prevalent severe CNS disorders, which negatively affects social lives, the ability to work, and the health of people. As per the World Health Organisation (WHO), it is a psychological disorder that is estimated to be a leading disease by 2030. Clinically, various medicines have been formulated to treat depression but they are having a setback due to their side effects, slow action, or poor bioavailability. Nowadays, flavonoids are regarded as an essential component in a variety of nutraceutical, pharmaceutical and medicinal. Isoflavones are a distinctive and important subclass of flavonoids that are generally obtained from soybean, chickpeas, and red clover. The molecules of this class have been extensively explored in various CNS disorders including depression and anxiety. Isoflavones such as genistein, daidzein, biochanin-A, formononetin, and glycitein have been reported to exert an anti-depressant effect through the modulation of different mediators. Fatty acid amide hydrolase (FAAH) mediated depletion of anandamide and hypothalamic-pituitary-adrenal (HPA) axis-mediated modulation of brain-derived neurotrophic factor (BDNF), monoamine oxidase (MAO) mediated depletion of biogenic amines and inflammatory signaling are the important underlying pathways leading to depression. Upregulation in the levels of BDNF, anandamide, antioxidants and monoamines, along with inhibition of MAO, FAAH, HPA axis, and inflammatory stress are the major modulations produced by different isoflavones in the observed anti-depressant effect. Therefore, the present review has been designed to explore the mechanistic interplay of various mediators involved in mediating the anti-depressant action of different isoflavones.

Zuojin pill improves chronic unpredictable stress-induced depression-like behavior and gastrointestinal dysfunction in mice via the theTPH2/5-HT pathway

BACKGROUND

The complex bidirectional communication between the gastrointestinal tract and the brain is associated with mental disorders such as depression; serotonin, as a crucial neurotransmitter in the communication system between the central nervous system and the gastrointestinal tract, has effects on regulating gastrointestinal motility and sensation and improving psychosomatic status. Zuojin pill is used as a traditional Chinese medicine formula for the treatment of gastrointestinal disorders. This study explored the effects of Zuojin pill on the improvement of depression and gastrointestinal function in CUMS mice via TPH2 and its mechanism.

PURPOSE

The aim of this study was to investigate whether Zuojin pill could improve depression and concomitant gastrointestinal dysfunction, and to reveal whether Zuojin pill could work through the regulation of the tryptophan hydroxylase 2 (TPH2) pathway.

METHODS

The CUMS model was established to observe the effects of Zuojin pill on depression-like behavior and gastrointestinal function in mice. Nissler staining and HE staining were used to observe the structure of hippocampal neurons and intestinal mucosa respectively. 5-HT levels in serum, hippocampus, and intestinal tissues were measured by ELISA, and TPH2 expression in hippocampus and intestinal nerves was observed by WB and immunofluorescence. In order to investigate the protective effect and mechanism of Zuojin pill on PC12 cells, CORT used an in vitro model to produce PC12 cell damage.

RESULTS

Our study showed that Zuojin pill ameliorated depression-like behavior and gastrointestinal dysfunction in CUMS mice, elevated BDNF, 5-HT, and TPH2 expression in the hippocampus, and restored the ratio of dopaminergic and GABAergic neurons between intestinal muscles. In vitro experiments showed that Zuojin pill exerted a protective effect on neurons by regulating TPH2 ubiquitination and thus inhibiting CORT-induced apoptosis of PC12 cells.

CONCLUSION

Zuojin pill improves chronic unpredictable stress-induced depression-like behavior and gastrointestinal dysfunction in mice via the TPH2/5-HT pathway. Therefore, TPH2 may be a potential therapeutic target for depression with gastrointestinal dysfunction.

In Vitro Human Monoamine Oxidase Inhibition and Human Dopamine D4 Receptor Antagonist Effect of Natural Flavonoids for Neuroprotection

Natural flavone and isoflavone analogs such as 3',4',7-trihydroxyflavone (1), 3',4',7-trihydroxyisoflavone (2), and calycosin (3) possess significant neuroprotective activity in Alzheimer's and Parkinson's disease. This study highlights the in vitro human monoamine oxidase (hMAO) inhibitory potential and functional effect of those natural flavonoids at dopamine and serotonin receptors for their possible role in neuroprotection. In vitro hMAO inhibition and enzyme kinetics studies were performed using a chemiluminescent assay. The functional effect of three natural flavonoids on dopamine and serotonin receptors was tested via cell-based functional assays followed by a molecular docking simulation to predict interactions between a compound and the binding site of the target protein. A forced swimming test was performed in the male C57BL/6 mouse model. Results of in vitro chemiluminescent assays and enzyme kinetics depicted 1 as a competitive inhibitor of hMAO-A with promising potency (IC50 value: 7.57 ± 0.14 μM) and 3 as a competitive inhibitor of hMAO-B with an IC50 value of 7.19 ± 0.32 μM. Likewise, GPCR functional assays in transfected cells showed 1 as a good hD4R antagonist. In docking analysis, these active flavonoids interacted with a determinant-interacting residue via hydrophilic and hydrophobic interactions, with low docking scores comparable to reference ligands. The post-oral administration of 1 to male C57BL/6 mice did not reduce the immobility time in the forced swimming test. The results of this study suggest that 1 and 3 may serve as effective regulators of the aminergic system via hMAO inhibition and the hD4R antagonist effect, respectively, for neuroprotection. The route of administration should be considered.

Antidepressant-like effects of the Punica granatum and citalopram combination are associated with structural changes in dendritic spines of granule cells in the dentate gyrus of rats

Introduction: Natural products such as phytoestrogens-enriched foods or supplements have been considered as an alternative therapy to reduce depressive symptoms associated with menopause. It is known that the aqueous extract of Punica granatum (AE-PG) exerts antidepressant-like effects by activating β-estrogen receptors and facilitates the antidepressant response of the clinical drug citalopram (CIT). However, the effects on neuroplasticity are unknown. Objectvie investigated the antidepressant-like response of combining AE-PG and CIT at sub-optimal doses, analyzing their effects on the formation and maturation of dendrite spines in granule cells as well as on the dendrite complexity. Methods: Ovariectomized Wistar rats (3-month-old) were randomly assigned to one of the following groups: A) control (saline solution as vehicle of CIT and AE-PG, B) AE-PG at a sub-threshold dose (vehicle of CIT plus AE-PG at 0.125 mg/kg), C) CIT at a sub-threshold dose (0.77 mg/kg plus vehicle of AE-PG), and D) a combination of CIT plus AE-PG (0.125 mg/kg and 0.77 mg/kg, respectively). All rats were treated intraperitoneally for 14 days. Antidepressant-like effects were evaluated using the force swimming test test (FST). The complexity of dendrites and the number and morphology of dendrite spines of neurons were assessed in the dentate gyrus after Golgi-Cox impregnation. The expressions of the mature brain-derived neurotrophic factor (mBDNF) in plasma and of mBDNF and synaptophysin in the hippocampus, as markers of synaptogenesis, were also determined. Results: Administration of CIT combined with AE-PG, but not alone, induced a significant antidepressant-like effect in the FST with an increase in the dendritic complexity and the number of dendritic spines in the dentate gyrus (DG) of the hippocampus, revealed by the thin and stubby categories of neurons at the granular cell layer. At the same time, an increase of mBDNF and synaptophysin expression was observed in the hippocampus of rats that received the combination of AE-PG and CIT.

Antidepressant-like Effects of Representative Types of Food and Their Possible Mechanisms

Depression is a mental disorder characterized by low mood, lack of motivation, negative cognitive outlook, and sleep problems. Suicide may occur in severe cases, although suicidal thoughts are not seen in all cases. Globally, an estimated 350 million individuals grapple with depression, as reported by the World Health Organization. At present, drug and psychological treatments are the main treatments, but they produce insufficient responses in many patients and fail to work at all in many others. Consequently, treating depression has long been an important topic in society. Given the escalating prevalence of depression, a comprehensive strategy for managing its symptoms and impacts has garnered significant attention. In this context, nutritional psychiatry emerges as a promising avenue. Extensive research has underscored the potential benefits of a well-rounded diet rich in fruits, vegetables, fish, and meat in alleviating depressive symptoms. However, the intricate mechanisms linking dietary interventions to brain function alterations remain largely unexplored. This review delves into the intricate relationship between dietary patterns and depression, while exploring the plausible mechanisms underlying the impact of dietary interventions on depression management. As we endeavor to unveil the pathways through which nutrition influences mental well-being, a holistic perspective that encompasses multidisciplinary strategies gains prominence, potentially reshaping how we approach and address depression.

Investigating the antidepressant effect of Ziyan green tea on chronic unpredictable mild stress mice through fecal metabolomics

Introduction

Some studies have shown the effectiveness of tea in reducing depression. Gut flora dysfunction is strongly associated with depression. The mechanism by which Ziyan green tea ameliorates depression is not clear.

Methods

In this study, we examined the impact of Ziyan green tea on mice exhibiting symptoms similar to depression. We specifically focused on the role of intestinal flora and its metabolites. We first established a chronic unpredictable mild stress (CUMS) mouse model to induce depressive symptoms and conducted behavioural tests, biochemical tests, and pathological tissue analysis. We also investigated gut microbiota changes by 16S rRNA sequencing and measured faecal metabolites in mice using UHPLC-MS/MS.

Results

The results showed that Ziyan green tea intervention improved depression-like behaviour, neurobiochemical factors, and reduced levels of pro-inflammatory factors in CUMS mice. Spearman's correlation analysis showed that different microbial communities (Corynebacterium, Faecalibaculum, Enterorhabdus, Desulfovibrio) correlation with differential metabolites (Cholic acid, Deoxycholic acid, etc.) and depression-related biochemical indicators (5-HT, DA, BDNF, IL-6, and TNF-α).

Discussion

In conclusion, our findings suggest that both low and high-dose interventions of Ziyan green tea have positive preventive effects on CUMS mice without dose dependence, partly because they mainly affect intestinal Purine Metabolism, Bile Acid Biosynthesis and Cysteine Metabolism in CUMS mice, thus stimulating brain 5-HT, DA and BDNF, and decreasing the inflammatory factors IL-6, TNF-α, activate the composition of intestinal flora, improve the intestinal flora environment and thus promote the production of intestinal metabolites, which can be used for depression treatment. It is suggested that Ziyan green tea may achieve an antidepressant effect through the gut-microbiota-brain axis.

Polyphenols as novel interventions for depression: exploring the efficacy, mechanisms of action, and implications for future research

Numerous animal and human studies have assessed the relationship between polyphenols and outcomes related to depression. However, no comprehensive synthesis of the main findings has been conducted. The aim of this manuscript was to systematically review the available evidence from animal and human studies on the association and the effects of dietary polyphenols on depression and provide recommendations for future research. We based our review on 163 preclinical animal, 16 observational and 44 intervention articles assessing the relationship between polyphenols and outcomes related to depression. Most animal studies demonstrated that exposure to polyphenols alleviated behaviours reported to be associated with depression. However, human studies are less clear, with some studies reporting and inverse relationship between the intake of some polyphenols, and polyphenol rich foods and depression risk and symptoms, while others reporting no association or effect. Hence, while there has been extensive research conducted in animals and there is some supporting evidence in humans, further human studies are required, particularly in younger and clinical populations.

Natural Phytochemicals for the Treatment of Major Depressive Disorder: A Mini-Review of Pre- and Clinical Studies

Major Depressive Disorder (MDD) is a common mental illness that causes significant disability and declining quality of life. An overlap of multiple factors can be involved in the pathophysiology of this mood disorder, including increased inflammation and oxidative stress, change in neurotransmitters, decreased brain-derived neurotrophic factor (BDNF), activation of the hypothalamicpituitary- adrenal (HPA) axis, and changes in the microbiota-gut-brain axis. Although the classic treatment for MDD is safe, it is far from ideal, with delay to start the best clinic, side effects, and a large number of non-responses or partial-responses. Therefore, other alternatives are being studied to improve depressive symptoms, and, among them, the role of phytochemicals in food stands out. This mini-review will discuss the main phytochemicals present in foods with clinical and preclinical studies showing benefits for MDD treatment. In addition, the main mechanisms of action that are being proposed for each of these compounds will be addressed.

Mechanistic insights into the role of plant polyphenols and their nano-formulations in the management of depression

Depression is a condition characterized by low mood and an aversion to activity, that causes behavioral problems, poor quality of life and limits daily life activities. It is considered as the fourth leading cause of disability worldwide. Selective Serotonin Reuptake Inhibitors (SSRIs) Monoamine Oxidase (MAO) inhibitors, Tricyclic Antidepressants (TCAs), and atypical antidepressants are some of the conventional medications used to treat depression. However, only about half of patients with major depressive disorder (MDD) respond effectively to first-line antidepressant therapy. Additionally, there are a number of drawbacks to standard antidepressants, such as anti-cholinergic side effects, drug-drug interactions, and food-drug interactions, which prompts researchers to look at alternative approaches to the treatment of depression. Medicinal plants and their metabolites are extensively tested for their efficacy against depression. Electronic databases such as Google scholar, Science Direct, SciFinder and PubMed were used to search relevant literature on the role of polyphenols in depression. Plants-derived Polyphenols represent a major class of compounds extensively distributed in plants. Number of polyphenols have demonstrated antidepressant activity, among which berberine, piperine, curcumin, naringenin, ascorbic acid and ginsenosides are extensively evaluated. The medicinal plants and their derived compounds mediated synthesized green nanoparticles have also exhibited considerable efficacy in the management of depression. The therapeutic effects of these phytochemicals is mediated via differentiation and inhibition of neuronal cell apoptosis, promotion of neuronal cell survival and modulation of key neurotransmitters. The aim of this study is to review compressively the chemical, pharmacological and neurological evidence showing the potential of polyphenols in depression.

Fatty acid amide hydrolase inhibition and N-arachidonoylethanolamine modulation by isoflavonoids: A novel target for upcoming antidepressants

Modulation of the endocannabinoid system (ECS) is a novel putative target for therapeutic intervention in depressive disorders. Altering concentrations of one of the principal endocannabinoids, N‐arachidonoylethanolamine, also known as anandamide (AEA) can affect depressive‐like behaviors through several mechanisms including anti‐inflammatory, hormonal, and neural circuit alterations. Recently, isoflavonoids, a class of plant‐derived compounds, have been of therapeutic interest given their ability to modulate the metabolism of the endogenous ligands of the ECS. To determine the therapeutic potential of isoflavonoids, we screened several candidate compounds (Genistein, Biochanin‐A, and 7‐hydroxyflavone) in silico to determine their binding properties with fatty acid amide hydrolase (FAAH), the primary degrative enzyme for AEA. We further validated the ability of these compounds to inhibit FAAH and determined their effects on depressive‐like and locomotor behaviors in the forced swim test (FST) and open field test in male and female mice. We found that while genistein was the most potent FAAH inhibitor, 7‐hydroxyflavone was most effective at reducing immobility time in the forced swim test. Finally, we measured blood corticosterone and prefrontal cortex AEA concentrations following the forced swim test and found that all tested compounds decreased corticosterone and increased AEA, demonstrating that isoflavonoids are promising therapeutic targets as FAAH inhibitors.

Multi-strain Probiotic Formulation Reverses Maternal Separation and Chronic Unpredictable Mild Stress-Generated Anxiety- and Depression-like Phenotypes by Modulating Gut Microbiome-Brain Activity in Rats

Depression is a debilitating mental disorder that affects >322 million people worldwide. Despite the availability of several antidepressant agents, many patients remain treatment refractory. A growing literature study has indicated the role of gut microbiota in neuropsychiatric disorders. Herein, we examined the psychobiotic-like activity of multi-strain probiotic formulation in maternal separation (MS) and chronic unpredictable mild stress (CUMS) models of anxiety- and depression-like phenotypes in Sprague-Dawley rats. Early- and late-life stress was employed in both male and female rats by exposing them to MS and CUMS. The multi-strain probiotic formulation (Cognisol) containing Bacillus coagulans Unique IS-2, Lactobacillus plantarum UBLP-40, Lactobacillus rhamnosus UBLR-58, Bifidobacterium lactis UBBLa-70, Bifidobacterium breve UBBr-01, and Bifidobacterium infantis UBBI-01 at a total strength of 10 billion cfu along with l-glutamine was administered for 6 weeks via drinking water. Neurobehavioral assessment was done using the forced swim test (FST), sucrose preference test (SPT), elevated plus maze (EPM), and open field test (OFT). Animals were sacrificed after behavioral assessment, and blood, brain, and intestine samples were collected to analyze the levels of cytokines, metabolites, and neurotransmitters and histology. Animals exposed to stress showed increased passivity, consumed less sucrose solution, and minimally explored the open arms in the FST, SPT, and EPM, respectively. Administration of multi-strain probiotics along with l-glutamine for 6 weeks ameliorated the behavioral abnormalities. The locomotor activity of animals in the OFT and their body weight remained unchanged across the groups. Cognisol treatment reversed the decreased BDNF and serotonin levels and increased CRP, TNF-α, and dopamine levels in the hippocampus and/or frontal cortex. Administration of Cognisol also restored the plasma levels of l-tryptophan, l-kynurenine, kynurenic-acid, and 3-hydroxyanthranilic acid; the Firmicutes-to-Bacteroides ratio; the levels of acetate, propionate, and butyrate in fecal samples; the villi/crypt ratio; and the goblet cell count, which manifested in the restoration of intestinal functions. We suggest that the multi-strain probiotic and glutamine formulation (Cognisol) ameliorated the MS + UCMS-generated anxiety- and depression-like phenotypes by reshaping the gut microbiome-brain activity in both sexes.

The Role of Natural Products in Treatment of Depressive Disorder

Depressive disorder is one of the most common psychiatric syndromes that, if left untreated, can cause many disturbances in a person's life. Numerous factors are involved in depression, including inflammation, brain-derived neurotrophic factor (BDNF), GABAergic system, hypothalamic- pituitary-adrenal (HPA) Axis, monoamine neurotransmitters (serotonin (5-HT), noradrenaline, and dopamine). Common treatments for depression are selective serotonin reuptake inhibitors, tricyclic antidepressants, and monoamine oxidase inhibitors, but these drugs have several side effects such as anxiety, diarrhea, constipation, weight loss, and sexual dysfunctions. These agents only reduce the symptoms and temporarily reduce the rate of cognitive impairment associated with depression. As a result, extensive research has recently been conducted on the potential use of antidepressant and sedative herbs. According to the available data, herbs used in traditional medicine can be significantly effective in reducing depression, depressive symptoms and improving patients' performance. The present study provides a summary of biomarkers and therapeutic goals of depression and shows that natural products such as saffron or genipin have antidepressant effects. Some of the useful natural products and their mechanisms were evaluated. Data on various herbs and natural isolated compounds reported to prevent and reduce depressive symptoms is also discussed.

The therapeutic potential of traditional Chinese medicine in depression: Targeting adult hippocampal neurogenesis

BACKGROUND

Depression is a common mental disorder characterized by persistent sadness and lack of interest or pleasure in previously rewarding or enjoyable activities. Understandably, the causes of depression are complex. Nevertheless, the understanding of depression pathophysiology has progressed considerably and numerous studies indicate that hippocampal neurogenesis plays a pivotal role. However, no drugs specifically targeting hippocampal neurogenesis yet exist. Meanwhile, the effects of traditional Chinese medicine (TCM) on hippocampal neurogenesis have received increasing attention in the field of antidepressant treatment because of its multi-ingredient, multi-target, and holistic view. However, the effects and mechanisms of TCM on hippocampal neurogenesis in clinical trials and pharmaceutical studies remain to be comprehensively delineated.

PURPOSE

To summarize the importance of hippocampal neurogenesis in depression and illustrate the targets and mechanisms of hippocampal neurogenesis regulation that underlie the antidepressant effects of TCM.

METHOD

A systematic review of clinical trials and studies ending by January 2022 was performed across eight electronic databases (Web of Science, PubMed, SciFinder, Research Gate, ScienceDirect, Google Scholar, Scopus and China Knowledge Infrastructure) according to the PRISMA criteria, using the search terms 'traditional Chinese medicine' "AND" 'depression' "OR" 'hippocampal neurogenesis' "OR" 'multi-ingredient' "OR" 'multi-target'.

RESULTS

Numerous studies show that hippocampal neurogenesis is attenuated in depression, and that antidepressants act by enhancing hippocampal neurogenesis. Moreover, compound Chinese medicine (CCM), Chinese meteria medica (CMM), and major bioactive components (MBCs) can promote hippocampal neurogenesis exerting antidepressant effects through modulation of neurotransmitters and receptors, neurotrophins, the hypothalamic-pituitary-adrenal axis, inflammatory factors, autophagy, and gut microbiota.

CONCLUSION

We have comprehensively summarized the effect and mechanism of TCM on hippocampal neurogenesis in depression providing a unique perspective on the use of TCM in the antidepressant field. TCM has the characteristics and advantages of multiple targets and high efficacy, showing great potential in the field of depression treatment.

Jasmine Tea Attenuates Chronic Unpredictable Mild Stress-Induced Depressive-like Behavior in Rats via the Gut-Brain Axis

The number of depressed people has increased worldwide. Dysfunction of the gut microbiota has been closely related to depression. The mechanism by which jasmine tea ameliorates depression via the brain-gut-microbiome (BGM) axis remains unclear. Here, the effects of jasmine tea on rats with depressive-like symptoms via the gut microbiome were investigated. We first established a chronic unpredictable mild stress (CUMS) rat model to induce depressive symptoms and measured the changes in depression-related indicators. Simultaneously, the changes in gut microbiota were investigated by 16S rRNA sequencing. Jasmine tea treatment improved depressive-like behaviors and neurotransmitters in CUMS rats. Jasmine tea increased the gut microbiota diversity and richness of depressed rats induced by CUMS. Spearman’s analysis showed correlations between the differential microbiota (Patescibacteria, Firmicutes, Bacteroidetes, Spirochaetes, Elusimicrobia, and Proteobacteria) and depressive-related indicators (BDNF, GLP-1, and 5-HT in the hippocampus and cerebral cortex). Combined with the correlation analysis of gut microbiota, the result indicated that jasmine tea could attenuate depression in rats via the brain- gut-microbiome axis.

Dietary Intake of Flavonoids and Carotenoids Is Associated with Anti-Depressive Symptoms: Epidemiological Study and In Silico-Mechanism Analysis

Flavonoids and carotenoids are bioactive compounds that have protective effects against depressive symptoms. Flavonoids and carotenoids are the two main types of antioxidant phytochemicals. This study investigated the association between flavonoid and carotenoid intake and depressive symptoms in middle-aged Korean females. We analyzed the mechanism of these associations using an in silico method. Depressive symptoms were screened using the Beck Depression Inventory-II (BDI-II), and flavonoid and carotenoid intake were assessed using a semi-quantitative food frequency questionnaire. Using a multivariate logistic regression model, we found that flavones, anthocyanins, individual phenolic compounds, lycopene, and zeaxanthin were negatively associated with depressive symptoms. In silico analysis showed that most flavonoids have high docking scores for monoamine oxidase A (MAOA) and monoamine oxidase B (MAOB), which are two important drug targets in depression. The results of the docking of brain-derived neurotrophic factor (BDNF) and carotenoids suggested the possibility of allosteric activation of BDNF by carotenoids. These results suggest that dietary flavonoids and carotenoids can be utilized in the treatment of depressive symptoms.

Genistein, a Natural Isoflavone, Alleviates Seizure-Induced Respiratory Arrest in DBA/1 Mice

Objective: Sudden unexpected death in epilepsy (SUDEP) is a fatal event that ranks second in years of potential life lost among neurological disorders. Seizure-induced respiratory arrest (S-IRA) is the primary instigator leading to death in many SUDEP cases. However, there are currently no effective preventive strategies against S-IRA other than the seizure control. Therefore, it is critical to develop new avenues to prevent SUDEP by investigating the pharmacological interventions of S-IRA. In the present study, we examined the effect of genistein, an isoflavone found in various dietary vegetables, on the incidence of S-IRA in DBA/1 mice.

Methods: DBA/1 mice exhibited generalized seizures and S-IRA when subjected to acoustic stimulation. Genistein was intraperitoneally administered alone or in combination with an adrenoceptor antagonist and a serotonin (5-HT) receptor antagonist, respectively. The effects of drug treatments on S-IRA incidence and seizure behaviors were examined.

Results: The incidence of S-IRA in DBA/1 mice was significantly reduced 2 h after injection of genistein at 1–90 mg/kg as compared with that in the vehicle control. Genistein could block S-IRA without interfering with any component of seizures, especially at relatively lower dosages. The S-IRA-suppressing effect of genistein was reversed by an α2 adrenoceptor antagonist but was not altered by an α1 antagonist. The inhibitory effect of genistein on S-IRA was not affected by a 5-HT₃ or 5-HT_2A receptor antagonist.

Significance: Our data show that genistein reduces S-IRA incidence and can specifically block S-IRA in DBA/1 mice. Its suppressing effect on S-IRA is dependent on activating α2 adrenoceptors. Our study suggests that genistein, a dietary supplement, is potentially useful to prevent SUDEP in at-risk patients.

Genistein acts as antidepressant agent against chronic mild stress-induced depression model of rats through augmentation of brain-derived neurotrophic factor

In this study, the antidepression effects of genistein were investigated in rats induced with chronic mild stress. Animals were designated into the following groups: normal control, control, 10 mg, and 100 mg. The dose was given for 45 consecutive days via the oral route. Sucrose preference analysis, forced swim, and open field tests were performed, and serum cortisol and monoamine levels in brain tissue were determined. The mRNA and protein expression of brain-derived neurotrophic factor (BDNF) was also examined. Supplementation with genistein significantly increased the sucrose preference ratio, locomotor activity, and monoamines and decreased serum cortisol levels. The mRNA expression of BDNF in the brain tissue was substantially reduced by 0.73% in control rats. However, supplementation with genistein significantly increased BDNF mRNA expression (by 107% and 229.6% in groups 10 mg and 100 mg, respectively). Similarly, the protein expression of BDNF increased by 82.3% and 141.2% in groups 10 mg and 100 mg, respectively. Taken together, these results suggest that supplementation with genistein may be effective against depression.

Current Perspectives on the Beneficial Effects of Soybean Isoflavones and Their Metabolites for Humans

Soybeans are rich in proteins and lipids and have become a staple part of the human diet. Besides their nutritional excellence, they have also been shown to contain various functional components, including isoflavones, and have consequently received increasing attention as a functional food item. Isoflavones are structurally similar to 17-β-estradiol and bind to estrogen receptors (ERα and ERβ). The estrogenic activity of isoflavones ranges from a hundredth to a thousandth of that of estrogen itself. Isoflavones play a role in regulating the effects of estrogen in the human body, depending on the situation. Thus, when estrogen is insufficient, isoflavones perform the functions of estrogen, and when estrogen is excessive, isoflavones block the estrogen receptors to which estrogen binds, thus acting as an estrogen antagonist. In particular, estrogen antagonistic activity is important in the breast, endometrium, and prostate, and such antagonistic activity suppresses cancer occurrence. Genistein, an isoflavone, has cancer-suppressing effects on estrogen receptor-positive (ER+) cancers, including breast cancer. It suppresses the function of enzymes such as tyrosine protein kinase, mitogen-activated kinase, and DNA polymerase II, thus inhibiting cell proliferation and inducing apoptosis. Genistein is the most biologically active and potent isoflavone candidate for cancer prevention. Furthermore, among the various physiological functions of isoflavones, they are best known for their antioxidant activities. S-Equol, a metabolite of genistein and daidzein, has strong antioxidative effects; however, the ability to metabolize daidzein into S-equol varies based on racial and individual differences. The antioxidant activity of isoflavones may be effective in preventing dementia by inhibiting the phosphorylation of Alzheimer's-related tau proteins. Genistein also reduces allergic responses by limiting the expression of mast cell IgE receptors, which are involved in allergic responses. In addition, they have been known to prevent and treat various diseases, including cardiovascular diseases, metabolic syndromes, osteoporosis, diabetes, brain-related diseases, high blood pressure, hyperlipidemia, obesity, and inflammation. Further, it also has positive effects on menstrual irregularity in non-menopausal women and relieving menopausal symptoms in middle-aged women. Recently, soybean consumption has shown steep increasing trend in Western countries where the intake was previously only 1/20-1/50 of that in Asian countries. In this review, I have dealt with the latest research trends that have shown substantial interest in the biological efficacy of isoflavones in humans and plants, and their related mechanisms.

Evidence for 5-HT1A receptor-mediated antiallodynic and antihyperalgesic effects of apigenin in mice suffering from mononeuropathy

BACKGROUND AND PURPOSE

Neuropathic pain places a devastating health burden, with very few effective therapies. We investigated the potential antiallodynic and antihyperalgesic effects of apigenin, a natural flavonoid with momoamine oxidase (MAO) inhibitory activity, against neuropathic pain and investigated the mechanism(s).

EXPERIMENTAL APPROACH

The neuropathic pain model was produced by chronic constriction injury of sciatic nerves in male C57BL/6J mice, with pain-related behaviours being assayed by von Frey test and Hargreaves test. In this model the role of 5-HT and 5-HT_1A receptor-related mechanisms were investigated in vivo/in vitro.

KEY RESULTS

Apigenin repeated treatment (p.o., once per day for 2 weeks), in a dose-related manner (3, 10 and 30 mg·kg^-1 ), ameliorated the allodynia and hyperalgesia in chronic nerve constriction injury in mice. These effects seem dependent on neuronal 5-hydroxytryptamine, because (i) the antihyperalgesia and antiallodynia were attenuated by depletion of 5-HT with p-chlorophenylalanine and potentiated by 5-hydroxytryptophan and (ii), apigenin-treated chronic constriction injury mice caused an increased level of spinal 5-HT, associated with diminished MAO activity. In vivo administration, spinally or systematically, of the 5-HT_1A antagonist WAY-100635 inhibited the apigenin-induced antiallodynia and antihyperalgesia. In vitro, apigenin acted as a positive allosteric modulator to increase the efficacy (stimulation of [³⁵ S]GTPγS binding) of the 5-HT_1A agonist 8-OH-DPAT. Apigenin attenuated neuronal changes caused by chronic constriction of the sciatic nerve in mice, without causing a hypertensive crisis.

CONCLUSION AND IMPLICATIONS

Apigenin antiallodynic and antihyperalgesic actions against neuropathic pain crucially involve spinal 5-HT_1A receptors and indicate it could be used to treat neuropathic pain.

Serotonergically dependent antihyperalgesic and antiallodynic effects of isoliquiritin in a mouse model of neuropathic pain

Chronic neuropathic pain poses a significant health problem worldwide, for which effective treatment is lacking. The current work aimed to investigate the potential analgesic effect of isoliquiritin, a flavonoid from Glycyrrhiza uralensis, against neuropathic pain and elucidate mechanisms. Male C57BL/6J mice were subjected to chronic constriction injury (CCI) by loose ligation of their sciatic nerves. Following CCI surgery, the neuropathic mice developed pain-like behaviors, as shown by thermal (heat) hyperalgesia in the Hargreaves test and tactile allodynia in the von Frey test. Repetitive treatment of CCI mice with isoliquiritin (p.o., twice per day for two weeks) ameliorated behavioral hyperalgesia to thermal (heat) stimuli and allodynia to tactile stimuli in a dose-dependent fashion (5, 15 and 45 mg/kg). The isoliquiritin-triggered analgesia seems serotonergically dependent, since its antihyperalgesic and antiallodynic actions were totally abolished by chemical depletion of spinal serotonin by p-chlorophenylalanine, whereas potentiated by 5-HTP (a precursor of 5-HT). Consistently, isoliquiritin-treated neuropathic mice showed escalated levels of spinal monoamines especially 5-HT, with depressed monoamine oxidase activity. Moreover, isoliquiritin-evoked antihyperalgesia and antiallodynia were preferentially counteracted by the 5-HT_1A receptor antagonist WAY-100635 delivered systematically or spinally. Of notable benefit, isoliquiritin was able to correct co-morbid behavioral symptoms of depression and anxiety evoked by neuropathic pain. Collectively, these findings demonstrate, for the first time, the therapeutic efficacy of isoliquiritin on neuropathic hypersensitivity, and this effect is dependent on the spinal serotonergic system and 5-HT_1A receptors.

Traditional Chinese Medicine in Depression Treatment: From Molecules to Systems

Depression is a multigenetic or multifactorial syndrome. The central neuron system (CNS)-orientated, single target, and conventional antidepressants are insufficient and far from ideal. Traditional Chinese Medicine (TCM) has historically been used to treat depression up till today, particularly in Asia. Its holistic, multidrug, multitarget nature fits well with the therapeutic idea of systems medicine in depression treatment. Over the past two decades, although efforts have been made to understand TCM herbal antidepressants at the molecular level, many fundamental questions regarding their mechanisms of action remain to be addressed at the systems level in order to better understand the complicated herbal formulations in depression treatment. In this Mini Review, we review and discuss the mechanisms of action of herbal antidepressants and their acting targets in the pathological systems in the brain, such as monoamine neurotransmissions, hypothalamic–pituitary–adrenal (HPA) axis, neurotropic factor brain-derived neurotrophic factor (BDNF) cascade, and glutamate transmission. Some herbal molecules, constituents, and formulas are highlighted as examples to discuss their mechanisms of action and future directions for comprehensive researches at the systems level. Furthermore, we discuss pharmacological approaches to integrate the mechanism of action from the molecular level into the systems level for understanding of systems pharmacology of TCM formulations. Integration of the studies at the molecular level into the systems level not only represents a trend in TCM study but also promotes our understanding of the system-wide mechanism of action of herbal antidepressant formulations.

Genistein Prevents Single Prolonged Stress-Induced Cognitive Impairment in a Post-Traumatic Stress Disorder Rat Model via Activation of the Serotonergic System

Post-traumatic stress disorder (PTSD) is a stress-associated mental disorder characterized by an imbalance of neurotransmitters in response to traumatic events or fear. Genistein (GEN), a natural isoflavone, has been shown to exhibit neuroprotective effects. Here, we used the Morris water maze (MWM) and object recognition task (ORT) tests to examine the effects of GEN on cognitive impairment in rats after exposure to single prolonged stress (SPS), and its interaction with the serotonergic system. After exposure to SPS, male rats received GEN (2, 4, and 10 mg/kg, i.p.) for 14 days. Daily GEN administration significantly improved cognitive function in the ORT and MWM tests. GEN treatment also inhibited SPS-induced decreases in serotonin (5-HT) levels in the medial prefrontal cortex and hippocampus. These increased 5-HT concentrations in response to GEN treatment could be partially attributed to the ratio of 5-hydroxyindoleacetic acid/5-HT in the hippocampus. Our findings suggest that GEN significantly attenuates SPS-induced memory deficits in rats and may represent an effective therapeutic option for the treatment of PTSD.

Isorhynchophylline Exerts Antinociceptive Effects on Behavioral Hyperalgesia and Allodynia in a Mouse Model of Neuropathic Pain: Evidence of a 5-HT1A Receptor-Mediated Mechanism

Chronic neuropathic pain poses a significant health problem, for which effective therapy is lacking. The current work aimed to investigate the potential antinociceptive efficacy of isorhynchophylline, an oxindole alkaloid, against neuropathic pain and elucidate mechanisms. Male C57BL/6J mice were subjected to chronic constriction injury (CCI) by loose ligation of their sciatic nerves. Following CCI surgery, the neuropathic mice developed pain-like behaviors, as shown by thermal hyperalgesia in the Hargreaves test and tactile allodynia in the von Frey test. Repetitive treatment of CCI mice with isorhynchophylline (p.o., twice per day for two weeks) ameliorated behavioral hyperalgesia and allodynia in a dose-dependent fashion (5, 15, and 45 mg/kg). The isorhynchophylline-triggered antinociception seems serotonergically dependent, since its antinociceptive actions on neuropathic hyperalgesia and allodynia were totally abolished by chemical depletion of spinal serotonin by PCPA, whereas potentiated by 5-HTP (a precursor of 5-HT). Consistently, isorhynchophylline-treated neuropathic mice showed escalated levels of spinal monoamines especially 5-HT, with depressed monoamine oxidase activity. Moreover, the isorhynchophylline-evoked antinociception was preferentially counteracted by co-administration of 5-HT_1A receptor antagonist WAY-100635. In vitro, isorhynchophylline (0.1-10 nM) increased the Emax (stimulation of [³⁵S] GTPγS binding) of 8-OH-DPAT, a 5-HT_1A agonist. Of notable benefit, isorhynchophylline was able to correct co-morbidly behavioral symptoms of depression and anxiety evoked by neuropathic pain. Collectively, these findings confirm, for the first time, the disease-modifying efficacy of isorhynchophylline on neuropathic hypersensitivity, and this effect is dependent on spinal serotonergic system and 5-HT_1A receptors.

Genistein inhibits high fat diet-induced obesity through miR-222 by targeting BTG2 and adipor1

Obesity and diabetes mellitus have become major health problems worldwide. In recent years, genistein has been found to be capable of inhibiting obesity and alleviating insulin resistance. However, the molecular mechanism of genistein against obesity is still not fully understood. In this study, we used 3T3-L1 preadipocytes and obese mice as models to explore the molecular mechanism of genistein against obesity. We found that genistein can inhibit obesity and downregulate the expression of miR-222 in mouse adipose tissue. In 3T3-L1 preadipocytes, treatment with miR-222 inhibitor or genistein reduced the expression of miR-222 and promoted lipid decomposition, while miR-222 treatment increased the expression of miR-222 and inhibited lipolysis. Moreover, the dual-luciferase reporter assay system confirmed that BTG2 and adipor1 are the target genes of miR-222. Experiments conducted in vitro and in vivo suggest that genistein may regulate lipid metabolism in the adipose tissue of obese mice by regulating the expression of miR-222 and its target genes, BTG2 and adipor1. Our findings provide a new epigenetic mechanism underpinning the ability of genistein to resist obesity. These results may provide a reference point for the dietary treatment of obesity and type 2 diabetes mellitus.

Purpurin exerted antidepressant-like effects on behavior and stress axis reactivity: evidence of serotonergic engagement

RATIONALE AND OBJECTIVES

Major depression represents a significant public health problem worldwide, and effective regimen is lacking. The present study investigated the antidepressant-like effects of purpurin, a natural anthraquinone compound from Rubia tinctorum L., and explored the underlying mechanism(s).

METHODS

Forced swim test (FST) and tail suspension test (TST) were used to assess antidepressant-like effects of purpurin in mice. Effects of purpurin on neuroendocrine responsivity were evaluated at the level of corticosterone and ACTH following acute restraint stress and intracerebroventricular injection of corticotrophin-releasing-factor (CRF). Serotonergic mechanisms underlying purpurin antidepressant effect were explored using biochemical, neurochemical, and pharmacological paradigms.

RESULTS

Chronic purpurin treatment exerted in mice dose-dependently antidepressant-like effects on behavior and stress axis reactivity (n = 9-11 per group). The purpurin-triggered antidepressant-like effects are serotonergically dependent, since purpurin-treated mice showed escalated levels of brain serotonin and suppressed monoamine oxidase (MAO) activity (n = 8-11 per group). Consistently, chemical depletion of brain serotonin by p-chlorophenylalanine (PCPA) abolished the antidepressant-like effects of purpurin on behavior and stress axis responsivity (n = 9-10 per group). Moreover, the antidepressant effect by purpurin was preferentially counteracted by 1A-selective 5-HT receptor antagonist WAY-100635, but potentiated by 1A-selective agonist 8-OH-DPAT and sub-effective dose of serotonergic antidepressant fluoxetine (n = 9-11 per group), suggesting a crucial role for 5-HT1A related serotonergic system in mediating such purpurin antidepressant effect.

CONCLUSION

We have revealed the antidepressant-like effects of purpurin on both behavior and stress axis reactivity in mice, with serotonergic system that preferentially couples with 5-HT1A receptors being critically engaged.

Recovery of High Value-Added Nutrients from Fruit and Vegetable Industrial Wastewater

The industrial processing water of fruit and vegetables has raised serious environmental concerns due to the presence of many important bioactive compounds being disposed in the wastewater. Bioactive compounds have great potential for the food industry to optimize their process and to recover these compounds in order to develop value-added products and to reduce environmental impacts. However, to achieve this goal, some challenges need to be addressed such as safety assurance, technology request, product regulations, cost effectiveness, and customer factors. Therefore, this review aims to summarize the recent advances of bioactive compounds recovery and the current challenges in wastewater from fruit and vegetable processing industry, including fruit and beverage, soybean by-products, starch and edible oil industry. Moreover, future direction for novel and green technology of bioactive compounds recovery are discussed, and a prospect of bioactive compounds reuse and sustainable development is proposed.

DNA Methylation Status in Cancer Disease: Modulations by Plant-Derived Natural Compounds and Dietary Interventions

The modulation of the activity of DNA methyltransferases (DNMTs) represents a crucial epigenetic mechanism affecting gene expressions or DNA repair mechanisms in the cells. Aberrant modifications in the function of DNMTs are a fundamental event and part of the pathogenesis of human cancer. Phytochemicals, which are biosynthesized in plants in the form of secondary metabolites, represent an important source of biomolecules with pleiotropic effects and thus provide a wide range of possible clinical applications. It is well documented that phytochemicals demonstrate significant anticancer properties, and in this regard, rapid development within preclinical research is encouraging. Phytochemicals affect several epigenetic molecular mechanisms, including DNA methylation patterns such as the hypermethylation of tumor-suppressor genes and the global hypomethylation of oncogenes, that are specific cellular signs of cancer development and progression. This review will focus on the latest achievements in using plant-derived compounds and plant-based diets targeting epigenetic regulators and modulators of gene transcription in preclinical and clinical research in order to generate novel anticancer drugs as sensitizers for conventional therapy or compounds suitable for the chemoprevention clinical setting in at-risk individuals. In conclusion, indisputable anticancer activities of dietary phytochemicals linked with proper regulation of DNA methylation status have been described. However, precisely designed and well-controlled clinical studies are needed to confirm their beneficial epigenetic effects after long-term consumption in humans.

Aqueous Extract of Pomegranate Alone or in Combination with Citalopram Produces Antidepressant-Like Effects in an Animal Model of Menopause: Participation of Estrogen Receptors

It has been reported that the aqueous extract of pomegranate (AE-PG) has polyphenols with estrogenic-like activities. The present work determines if AE-PG alone or in combination with the selective serotonin reuptake inhibitor, citalopram, has antidepressant-like effects. It was also analyzed the participation of estrogen receptors (ER). AE-PG (0.1, 1.0, 10, or 100 mg/kg) was evaluated in ovariectomized female Wistar rats subjected to the forced swimming test. The effects induced by AE-PG were compared with those of citalopram (2.5, 5.0, 10, and 20.0 mg/kg) and 17β-estradiol (E2; 2.5 5.0, and 10 μg/rat). Likewise, the combination of suboptimal doses of AE-PG (0.1 mg/kg) plus citalopram (2.5 mg/kg) was evaluated. To determine if ER participates in the antidepressant-like action of pomegranate, the estrogen antagonist tamoxifen (15 mg/kg) was administered with AE-PG (1 mg/kg). AE-PG produced antidepressant-like actions with a similar behavioral profile induced by citalopram and E2. Suboptimal doses of citalopram plus AE-PG produced antidepressant-like effects. Tamoxifen was able to block AE-PG's antidepressant-like actions. These results confirm the participation of ER in AE-PG's antidepressant-like effects. Furthermore, the additive effects observed with the combined treatment of AE-PG plus citalopram could be advantageous in the treatment of depressive disorders, such as menopause.