Chrysin restores memory deficit in hypothyroidism mice: Behavioral, neurochemical and computational approaches involving the neurotrophinergic system

Chrysin modulates the BDNF/TrkB/AKT/Creb neuroplasticity signaling pathway: Acting in the improvement of cognitive flexibility and declarative, working and aversive memory deficits caused by hypothyroidism in C57BL/6 female mice

Hypothyroidism is known to affect memory consolidation, and our prior research highlighted the potential of chrysin as a therapeutic agent to restore cognitive function. The present study aimed to investigate the action mechanism of chrysin on memory deficits in hypothyroid in C57BL/6 female mice. We assessed cognitive flexibility, declarative, working, and aversive memories while analyzing the BDNF/TrkB/AKT/Creb neuroplasticity signaling pathway and synaptic function in the hippocampus and prefrontal cortex. To induce hypothyroidism, mice were exposed to 0.1 % methimazole (MTZ) in the drinking water for 31 days. After confirming low thyroid hormones levels, the mice received either vehicle or chrysin (20 mg/kg) intragastrically once a day for 28 consecutive days. Memory tests were conducted in two separate experiments (experiment 1: Y-maze and reverse Morris water maze; experiment 2: object recognition task and step-down latency), ensuring no memories overlap. Following the tests, the brain samples were collected to analyses ex vivo. Hypothyroid mice exhibited deficits in cognitive flexibility and various memory types, along with altered protein expression related to the BDNF/TrkB/Creb signaling pathway and increased AKT levels in hippocampus and prefrontal cortex. Chrysin treatment effectively reversed these memory deficits, restored cognitive flexibility, and improved protein levels. Our findings suggest that hypothyroidism impairs cognitive flexibility and memory through the BDNF/TrkB/AKT/Creb pathway, which chrysin modulates, operating as a neuroprotector in hypothyroidism. This research sheds light on the potential therapeutic benefits of chrysin for memory-related issues in hypothyroidism.

Hypothyroidism Promotes Microglia M1 Polarization by Inhibiting BDNF-Promoted PI3K-Akt Signaling Pathway

INTRODUCTION

Hypothyroidism and its induced neurological-associated disorders greatly affect the health-related quality of patients' life. Meanwhile, microglia in brain have essential regulatory functions on neurodegeneration, but the underlying link between hypothyroidism and microglia function is largely ambiguous.

METHODS

We deciphered how hypothyroidism modulates the polarization of microglia by constructing methimazole-induced mice model and checking the expression pattern of biomarkers of microglia M1 polarization. Then, we used lipopolysaccharide (LPS)-treated BV2 cells to explore the effecting factors on microglia M1 polarization. Finally, global transcriptome sequencing (RNA-seq) was utilized to identify the underlying regulatory mechanisms.

RESULTS

We detected that biomarkers of microglia M1 polarization and pro-inflammatory cytokines were significantly increased in hypothyroidism mice brain; hypothyroidism could also repress the expression of BDNF and TrkB, and the anti-inflammatory cytokine such as IL-10. In BV2 cells, LPS treatment decreased expression of BDNF, IL-10, and Arg1, while BDNF overexpression (BDNF-OE) significantly reversed the inflammation induced by LPS. BDNF-OE significantly repressed expression of iNOS and TNF-α, but increased expression of IL-10 and Arg1. For mechanism, RNA-seq analysis demonstrated that BDNF-OE could globally regulate transcriptome profile by affecting gene expression. In LPS-treated BV2 cells, BDNF-OE significantly altered expression pattern of genes involved in PI3K-Akt signaling pathway, including Thbs3, Myc, Gdnf, Thbs1, and Ccnd1 as upregulated genes, and Gnb4, Fgf22, Pik3r3, Pgf, Cdkn1a, and Pdgfra as downregulated genes. Myc, Gdnf, Thbs1, and Ccnd1 showed much higher expression levels than other genes in PI3K-Akt signaling pathway and could be promising targets of BDNF in reversing microglia M1 polarization.

CONCLUSION

Our study demonstrated a sound conclusion that hypothyroidism promotes microglia M1 polarization by inhibiting BDNF expression in brain; BDNF could inhibit the M1 polarization of microglia by activating PI3K-Akt signaling pathway, which could serve as a promising therapeutic target for microglia-induced neurodegenerative or emotional disorders in future.

INTRODUCTION

Hypothyroidism and its induced neurological-associated disorders greatly affect the health-related quality of patients' life. Meanwhile, microglia in brain have essential regulatory functions on neurodegeneration, but the underlying link between hypothyroidism and microglia function is largely ambiguous.

METHODS

We deciphered how hypothyroidism modulates the polarization of microglia by constructing methimazole-induced mice model and checking the expression pattern of biomarkers of microglia M1 polarization. Then, we used lipopolysaccharide (LPS)-treated BV2 cells to explore the effecting factors on microglia M1 polarization. Finally, global transcriptome sequencing (RNA-seq) was utilized to identify the underlying regulatory mechanisms.

RESULTS

We detected that biomarkers of microglia M1 polarization and pro-inflammatory cytokines were significantly increased in hypothyroidism mice brain; hypothyroidism could also repress the expression of BDNF and TrkB, and the anti-inflammatory cytokine such as IL-10. In BV2 cells, LPS treatment decreased expression of BDNF, IL-10, and Arg1, while BDNF overexpression (BDNF-OE) significantly reversed the inflammation induced by LPS. BDNF-OE significantly repressed expression of iNOS and TNF-α, but increased expression of IL-10 and Arg1. For mechanism, RNA-seq analysis demonstrated that BDNF-OE could globally regulate transcriptome profile by affecting gene expression. In LPS-treated BV2 cells, BDNF-OE significantly altered expression pattern of genes involved in PI3K-Akt signaling pathway, including Thbs3, Myc, Gdnf, Thbs1, and Ccnd1 as upregulated genes, and Gnb4, Fgf22, Pik3r3, Pgf, Cdkn1a, and Pdgfra as downregulated genes. Myc, Gdnf, Thbs1, and Ccnd1 showed much higher expression levels than other genes in PI3K-Akt signaling pathway and could be promising targets of BDNF in reversing microglia M1 polarization.

CONCLUSION

Our study demonstrated a sound conclusion that hypothyroidism promotes microglia M1 polarization by inhibiting BDNF expression in brain; BDNF could inhibit the M1 polarization of microglia by activating PI3K-Akt signaling pathway, which could serve as a promising therapeutic target for microglia-induced neurodegenerative or emotional disorders in future.

Vitamin D3 Exerts a Neuroprotective Effect in Metabolic Syndrome Rats: Role of BDNF/TRKB/Akt/GS3Kβ Pathway

Metabolic syndrome (MetS) is usually associated with cognitive impairment, neuropathic pain, and reduced brain-derived neurotrophic factor (BDNF) levels. BDNF via tropomyosin receptor kinase B (TrkB) exerts neuroprotection by activating protein kinase B (Akt) to inhibit glycogen synthase kinase-3β (GSK3β). Although Vitamin D3 (VitD3) has demonstrated favorable metabolic and neuronal outcomes in MetS, the precise molecular mechanisms underlying its neuroprotective effects remain poorly elucidated. We aimed to test the hypothesis that VitD3 mitigates MetS-induced cognition deficits and neuropathic pain via modulating the BDNF/TRKB/Akt/GS3Kβ signaling pathway. MetS was induced in male rats by 10% fructose-supplemented water and 3% salt-enriched diet. After 6 weeks, normal and MetS rats received either vehicle or VitD3 (10 µg/kg/day) for an additional 6 weeks. Glycemic status, lipid profile, and behavioral changes were assessed. The advanced glycation end products (AGEs), and markers of inflammation (TNF-α and NF-κB), oxidative stress (malondialdehyde), and apoptosis (caspase3), as well as BDNF, TrkB, PI3K, Akt, GSK3β, phosphorylated tau, and amyloid beta (Aβ) were assessed in the cerebral cortex. MetS rats had deteriorated glycemic and lipid profiles, higher AGEs, reduced levels of BDNF, TrkB, PI3K, and active Akt, along with increased GSK3β levels, inflammation, oxidative stress, and apoptosis. These changes were associated with higher levels of cognitive impairment markers phosphorylated tau and Aβ, as well as behavioral changes indicative of cognitive impairment and neuropathic pain. VitD3 improved the cognitive and behavioral alterations, while mitigating the associated molecular derangements. Our results indicate that VitD3 may exert neuroprotective effects by modulating the BDNF/TrkB/PI3K/Akt/GSK3β signaling pathway.

Empagliflozin ameliorates olfactory bulbectomy-induced depression by mitigating oxidative stress and possible involvement of brain derived neurotrophic factor in diabetic rats

Empagliflozin, a sodium-glucose co-transporter 2 (SGLT2) inhibitor, has recently reported to prevent the depression in chronic animal model. The present study aimed to explore the antidepressant potential of empagliflozin using a neuroinflammation-mediated depression involving the olfactory bulbectomy (OBX) model in diabetic rats. A low dose of streptozotocin was injected to induce diabetes in all group of animals. Following the confirmation of hyperglycemia, OBX surgery was performed. Post-surgery, the drug treatments were administered orally for 14 consecutive days. The study evaluated the effects of daily oral administration of empagliflozin at doses of 5 and 10 mg/kg, alongside metformin (200 mg/kg) and clomipramine (50 mg/kg), on OBX-induced behavioral depression in rats. Separate sham and vehicle control groups were also maintained. Behavioral parameters in open field, forced swim test, elevated plus maze and splash test were recorded on 28th day. Results showed that empagliflozin, at the higher dose, significantly enhanced behavioral outcomes, evidenced by increased distance travelled, greater open arm entries, and reduced immobility, alongside a notable reduction in grooming time. Moreover, empagliflozin significantly restored the antioxidants level specifically Glutathione (GSH) and Catalase (CAT) in OBX insulted rat brain and decreased Lipid peroxidase (LPO). Notably, molecular docking study demonstrated a good binding affinity of empagliflozin for Brain-Derived Neurotrophic Factor (BDNF), suggesting that its antidepressant effects may be mediated through the modulation of the BDNF pathway. These findings support the potential therapeutic application of empagliflozin for depression, particularly in cases associated with neuroinflammation and oxidative stress.

Understanding the molecular pathway of triclosan-induced ADHD-like behaviour: Involvement of the hnRNPA1-PKM2-STAT3 feedback loop

Triclosan (TCS) is an environmental pollutant. In recent years, there has been increasing level of concern regarding the potential toxicity of TCS in animals and humans, especially its effects on the nervous system. However, whether TCS induces ADHD-like behaviour and the mechanism by which it affects neural function are unclear. The impact of 60 days of continuous exposure to TCS on the behaviour of offspring rats was assessed in this research. According to the results of this study, TCS exposure led to ADHD-like behaviour in offspring rats and activated microglia in the prefrontal cortex (PFC), inducing inflammatory factor release. In vitro studies showed that TCS increased the levels of inflammatory cytokines, including interleukin (IL)-1β, IL-6 and tumour necrosis factor (TNF)-α, in HMC3 cells. More importantly, we found that TCS regulated the STAT3 pathway by upregulating PKM2 via hnRNPA1. In summary, this study suggested that TCS can induce ADHD-like behaviour in offspring rats and continuously activate HMC3 microglia through the hnRNPA1-PKM2-STAT3 feedback loop, promoting inflammatory cytokine secretion.

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.

Update on new trends and progress of natural active ingredients in the intervention of Alzheimer's disease, based on understanding of traditional Chinese and Western relevant theories: A review

Alzheimer's disease (AD) is one of the major neurological disorders causing death in the elderly worldwide. As a neurodegenerative disease that is difficult to prevent and cure, the pathogenesis of AD is complex and there is no effective cure. A variety of natural products derived from plants have been reported to have promising anti-AD activities, including flavonoids, terpenes, phenolic acids and alkaloids, which can effectively relieve the symptoms of AD in a variety of ways. This paper mainly reviews the pharmacological activity and mechanisms of natural products against AD. Although the clinical efficacy of these plants still needs to be determined by further high-quality studies, it may also provide a basis for future researchers to study anti-AD in depth.

The memory impairment by hypothyroidism in mice is dependent on time-of-day and sex

Hypothyroidism is an endocrine-metabolic disorder, and as such it compromises a wide range of physiological functions. Memory deficits and, the most recently described, circadian rhythm disruption are among the impairments caused by thyroid dysfunctions. However, although highly likely, there is no evidence connecting these two effects of hypothyroidism. Here, we hypothesized the time-of-day interferes with the memory deficit caused by hypothyroidism. C57BL/6 J mice from both sexes were subjected to novel object recognition (NOR) task during the rest and active phases, corresponding to ZT 2-4 and 14-16, respectively (ZT: Zeitgeber time; ZT 0: lights on at 07:00 am). First, we showed that neither sex nor ZT altered object recognition memory (ORM) in euthyroid mice. Next, animals were divided into control (euthyroid) and hypothyroid [induced with methimazole (0.01%) and perchlorate (0.1%) treatment in the drinking water for 21 days] groups. Under euthyroid conditions, male and female mice recognized the novel object regardless of the time-of-day. However, hypothyroidism impaired ORM at rest phase (ZT 2-4) in both sexes. Surprisingly, in the active phase (ZT 14-16), the hypothyroid males performed the NOR, though a longer time to execute the task was required. In contrast, female hypothyroid mice showed a greater impairment in ORM. Our results suggest that hypothyroidism may disrupt the circadian rhythm in brain areas related to mnemonic processes since in euthyroid condition ORM is not affected by the time-of-day. Furthermore, our findings in an animal model indicate a pronounced deleterious effect of hypothyroidism in women.

Chrysin loaded nanovesicles ameliorated diabetic peripheral neuropathy. Role of NGF/AKT/GSK-3β pathway

Diabetic peripheral neuropathy (DPN) is a common diabetic complication. Chrysin (CHY) has many biological properties but poor oral bioavailability. This study investigates the effect of CHY and CHY-loaded nanovesicles (CHY-NVs) on streptozotocin (STZ)-induced DPN in rats. CHY-NVs were prepared by using film hydration method. The formula with the best entrapment efficiency%, lowest particle size, highest zeta potential, and highest in vitro CHY released profile was selected, characterized by Differential scanning calorimetry, Fourier transformation infrared spectroscopy analysis, and examined by Transmission electron microscope. Acute toxicity test, pharmacokinetic study and experimental model of diabetes mellitus were performed on the selected formulation. Wistar rats were considered diabetic by administration of a single intraperitoneal dose of STZ (50 mg/kg). 48 h after STZ administration, hyperglycemic rats were randomly assigned into four groups, one group of untreated hyperglycemic rats and the other three groups received daily oral doses of unloaded NVs, CHY-NVs (25 mg/kg), and CHY-NVs (50 mg/kg), respectively for 21 days. Moreover, five additional groups of healthy rats received: distilled water (control), free CHY, unloaded NVs, and CHY-NVs respectively for 21 days. CHY and CHY-NVs maintained body weight and reduced STZ-induced behavioral changes in rotarod, hind paw cold allodynia, tail cold allodynia, tail flick, and hot plate tests. CHY and CHY-NVs lowered blood glucose, glycated hemoglobin, elevated serum reduced glutathione (GSH), and reduced plasma malondialdehyde (MDA) levels. CHY-NVs elevated phosphatidylinositol 3-kinase (Pi3k), phosphorylated protein kinase B (p-AKT), and reduced nuclear factor kappa B (NF-κB), interleukin-6 (IL-6) in sciatic nerve homogenate. CHY and CHY-NVs increased nerve growth factor (NGF) and decreased glycogen synthase kinase-3β (GSK-3β) gene expressions in the sciatic nerve. In conclusion, CHY and CHY-NVs ameliorated STZ-induced DPN behavioral and histopathological changes via attenuating hyperglycemia, exerting anti-oxidant, anti-inflammatory effects, activating NGF/p-AKT/GSK-3β pathway, and its anti-apoptotic effect. The best pharmacokinetic profile and therapeutic effect was observed in rats treated with CHY-loaded NVs.

Memory impairments in rodent depression models: A link with depression theories

More than 80% of depressed patients struggle with learning new tasks, remembering positive events, or concentrating on a single topic. These neurocognitive deficits accompanying depression may be linked to functional and structural changes in the prefrontal cortex and hippocampus. However, their mechanisms are not yet completely understood. We conducted a narrative review of articles regarding animal studies to assess the state of knowledge. First, we argue the contribution of changes in neurotransmitters and hormone levels in the pathomechanism of cognitive dysfunction in animal depression models. Then, we used numerous neuroinflammation studies to explore its possible implication in cognitive decline. Encouragingly, we also observed a positive correlation between increased oxidative stress and a depressive-like state with concomitant memory deficits. Finally, we discuss the undeniable role of neurotrophin deficits in developing cognitive decline in animal models of depression. This review reveals the complexity of depression-related memory impairments and highlights the potential clinical importance of gathered findings for developing more reliable animal models and designing novel antidepressants with procognitive properties.

Neurotrophins and Other Growth Factors in the Pathogenesis of Alzheimer’s Disease

The involvement of the changed expression/function of neurotrophic factors in the pathogenesis of neurodegenerative diseases, including Alzheimer’s disease (AD), has been suggested. AD is one of the age-related dementias, and is characterized by cognitive impairment with decreased memory function. Developing evidence demonstrates that decreased cell survival, synaptic dysfunction, and reduced neurogenesis are involved in the pathogenesis of AD. On the other hand, it is well known that neurotrophic factors, especially brain-derived neurotrophic factor (BDNF) and its high-affinity receptor TrkB, have multiple roles in the central nervous system (CNS), including neuronal maintenance, synaptic plasticity, and neurogenesis, which are closely linked to learning and memory function. Thus, many investigations regarding therapeutic approaches to AD, and/or the screening of novel drug candidates for its treatment, focus on upregulation of the BDNF/TrkB system. Furthermore, current studies also demonstrate that GDNF, IGF1, and bFGF, which play roles in neuroprotection, are associated with AD. In this review, we introduce data demonstrating close relationships between the pathogenesis of AD, neurotrophic factors, and drug candidates, including natural compounds that upregulate the BDNF-mediated neurotrophic system.

Interaction of fluoride exposure and CREB1 gene polymorphisms on thyroid function in school-age children

OBJECTIVES

To evaluate the effects of CREB1 gene polymorphisms and long-term exposure to fluoride on thyroid function of children.

STUDY DESIGN

A total of 424 children (including 226 boys and 198 girls) aged 7-12 years old were enrolled in Kaifeng, China by cross-sectional study in 2017. The concentrations of urinary fluoride (UF) and creatinine (UCr) were measured using fluoride ion-selective electrode assay and creatinine assay kit (picric acid method), respectively. The concentration of UCr-adjusted UF (CUF) was calculated. Children were divided into high fluoride exposure group (HFG, CUF >1.41 mg/L) and low fluoride exposure group (LFG, CUF ≤1.41 mg/L) according to the median concentration of CUF (1.41 mg/L). The serum thyroid-stimulating hormone (TSH), total triiodothyronine (TT3) and total thyronine (TT4) levels were detected by the radiation immunoassay. The B-mode ultrasound was performed to test the thyroid volume (Tvol). Genotyping of CREB1 gene was conducted by a custom-by-design 48-plex SNPscan™ Kit. Associations between CUF concentration, CREB1 single nucleotide polymorphisms (SNPs) and thyroid function were assessed by multiple linear regression models.

RESULTS

Negative and positive associations between serum TT4 level (β = -0.721, 95%CI: -1.209, -0.234) and Tvol (β = 0.031, 95%CI: 0.011, 0.050) and CUF concentration were observed respectively. Children carrying CREB1 rs11904814 TG and rs2254137 AC genotypes had lower TT3 levels (P < 0.05). Children in HFG carrying rs11904814 TT, rs2253206 GG genotypes and rs6740584 C allele easily manifested lower serum TT4 levels (P < 0.05). Moreover, interactions between excessive fluoride exposure and CREB1 SNPs on Tvol were observed, and the interaction among different loci of CREB1 gene could modify serum TT3 level (P < 0.05, respectively).

CONCLUSIONS

Fluoride could alter children's serum TT4 levels and Tvol. Interactions between fluoride exposure and CREB1 polymorphisms may modify thyroid volume of children.

Chronic Cerebral Hypoperfusion Aggravates Parkinson’s Disease Dementia-Like Symptoms and Pathology in 6-OHDA-Lesioned Rat through Interfering with Sphingolipid Metabolism

Chronic cerebral hypoperfusion (CCH) is a cardinal risk factor for Parkinson's disease dementia (PDD), but this potential causality lacks mechanistic evidence. We selected bilateral common carotid artery occlusion (BCCAO) to simulate chronic cerebral hypoperfusion in the rat model of PD induced by typical neurotoxin 6-hydroxy dopamine (6-OHDA). Four weeks after unilateral injection of 6-OHDA into the medial forebrain bundle, rats underwent BCCAO. Male Sprague-Dawley rats were divided into five groups of ten, including sham, PD+BCCAO 2 weeks, PD+BCCAO 1 week, PD, and BCCAO 2 weeks. Then, open field test (OFT) and Morris water maze test (MWM) were used to assess the PDD-like symptoms in rats. Also, the pathological manifestations and mechanisms of BCCAO impairing cognitive functions have been explored via hematoxylin-eosin staining, Nissl staining, immunohistochemistry, immunofluorescence, RNA sequencing analysis, lipidomics, and quantitative real-time polymerase chain reaction. In this study, we found that CCH could aggravate PDD-like cognitive symptoms (i.e., learning memory and spatial cognition) and PDD-like pathology (higher expression of α-Syn and Aβ in prefrontal cortex and striatum). Moreover, a potential relationship between differentially expressed mRNAs and lipid metabolism was revealed by RNA sequencing analysis. Lipidomics showed that CCH could affect the intensity of 5 lipids, including sphingomyelin (SM 9:0;2O/26:2; SM 8:1;2O/25:0; and SM 8:0;2O/28:4), cardiolipin, lysophosphatidylcholine, cholesteryl ester, and triacylglycerol. Interestingly, the KEGG pathway analysis of both RNA sequencing analysis and lipidomics suggested that CCH leaded to learning impairment by affecting sphingolipid metabolism. Finally, we found that CCH disrupts the sphingolipid metabolism by affecting the mRNA expression of SMPD1 and SMS2, leading to the accumulation of sphingomyelin in the prefrontal cortex. In summary, CCH, an independent exacerbating reason for impairment in learning and memory within the pathopoiesis of PD, aggravates Parkinson's disease dementia-like symptoms and pathology in 6-OHDA-lesioned rat through interfering with sphingolipid metabolism.

Pharmacological, Neurochemical, and Behavioral Mechanisms Underlying the Anxiolytic- and Antidepressant-like Effects of Flavonoid Chrysin

Chrysin (5,7-dihydroxyflavone) is a flavonoid isolated from plants, such as Passiflora coerulea, Passiflora incarnata, and Matricaria chamomilla. This natural molecule exerts diverse pharmacological effects, which includes antioxidant, anti-inflammatory, anti-cancer, neuroprotective, and anti-apoptotic effects. Additionally, in brain structures, such as the hippocampus, prefrontal cortex, raphe nucleus, and striatum, involved in the physiopathology of anxiety and depression disorders, several neuropharmacological activities, including the activation of neurotransmitter systems (GABAergic, serotonergic, dopaminergic, and noradrenergic), neurotrophic factors, such as brain-derived neurotrophic factor and the nerve growth factor, and some signaling pathways are affected. The results showed that the anxiolytic and antidepressant-like effects of chrysin occurs through its interaction with specific neurotransmitter systems, principally the GABAergic and the serotonergic, and activation of other neurotrophic factors. However, it is not possible to discard the antioxidant and anti-inflammatory activities of chrysin while producing its anxiolytic- and antidepressant-like effects. Although these results have been obtained principally from pre-clinical research, they consistently demonstrate the potential therapeutic use of flavonoid chrysin as an anxiolytic and antidepressant agent. Therefore, this flavonoid could be considered as a promising novel therapy for anxiety and depression disorders.