Naringenin attenuates behavioral derangements induced by social defeat stress in mice via inhibition of acetylcholinesterase activity, oxidative stress and release of pro-inflammatory cytokines

Exploration of the mechanism of Traditional Chinese Medicine for anxiety and depression in patients with diarrheal irritable bowel syndrome based on network pharmacology and meta-analysis

Background

The efficacy of Chinese herbal medicine (CHM) in managing irritable bowel syndrome with diarrhea (IBS-D) accompanied by anxiety and depression remains uncertain. Thus, a systematic review was carried out employing meta-analysis and network pharmacology to ascertain the efficacy and underlying mechanisms of CHM therapy.

Methods

By conducting a systematic review, including literature search, screening, and data extraction, we identified 25 randomized controlled trials to assess CHM's effectiveness in treating irritable bowel syndrome alongside anxiety and depression. Network pharmacology was utilized to scrutinize the metabolite utility of CHM in addressing this condition. Potential primary mechanisms were synthesized using information sourced from the PubMed database.

Results

Twenty-five studies, including 2055 patients, were analyzed, revealing significant treatment efficacy for IBS-D in the trial group compared to controls [OR = 4.01, 95% CI (2.99, 5.36), I2 = 0%] Additionally, treatment for depression [SMD = -1.08, 95% CI (-1.30, -0.86), p < 0.00001, I2 = 68%; SDS: SMD = -1.69, 95% CI (-2.48, -0.90), p < 0.0001, I2 = 96%] and anxiety [HAMA: SMD = -1.29, 95% CI (-1.68, -0.91), p < 0.00001, I2 = 89%; SAS: SMD = -1.75, 95% CI (-2.55, -0.95), p < 0.00001, I2 = 96%] significantly improved in the trial group. Furthermore, the trial group exhibited a significantly lower disease relapse rate [OR = 0.30, 95% CI (0.20, 0.44), p < 0.00001, I2 = 0%]. CHM treatment consistently improved IBS severity (IBS-SSS) and symptom scores. Network pharmacology analysis identified key chemical metabolites in traditional Chinese medicine formulations, including Beta-sitosterol, Stigmasterol, Quercetin, Naringenin, Luteolin, Kaempferol, Nobiletin, Wogonin, Formononetin, and Isorhamnetin. Utilizing the STRING database and Cytoscape v3.9.0 software, a protein-protein interaction (PPI) network revealed the top eight key targets: IL-6, TNF, PPARG, PTGS2, ESR1, NOS3, MAPK8, and AKT1, implicated in anti-inflammatory responses, antioxidant stress modulation, and neurotransmitter homeostasis maintenance.

Conclusion

Chinese Herbal Medicine (CHM) offers a promising and safe treatment approach for patients dealing with Diarrheal Irritable Bowel Syndrome (IBS-D) accompanied by anxiety and depression; thus, indicating its potential for practical implementation. The most active metabolites of CHM could simultaneously act on the pathological targets of IBS-D, anxiety, and depression.The diverse scope of CHM's therapeutic role includes various aspects and objectives, underscoring its potential for broad utilization.

Processed Polygonatum cyrtonema Hua attenuates postpartum depression in rat model by regulating monoamines and hormones

Background

Polygonatum cyrtonema Hua is a traditional Chinese medicinal food herb which can regulate the liver and Qi, nourish the heart and blood, moisten the lungs and nourish the kidneys with the potential to treat emotional diseases. However, few studies have explored the effects of Polygonatum cyrtonema Hua on postpartum depression. Therefore, we investigated whether processed Polygonatum cyrtonema Hua could improve postpartum depression in rat models by regulating monoamines and hormones.

Methods

Female Sprague-Dawley rats were randomized into normal control (0.9%Nacl), Sham operation (0.9%Nacl), postpartum depression model (0.9%Nacl), fluoxetine (2.5 mg/kg Fluoxetine), low, medium and high dose of processed Polygonatum cyrtonema Hua (2.5 g/kg, 5 g/kg, 10 g/kg) groups. Rats in these groups received drug intervention, and then subjected to Open-field test and Forced swimming test. Brain tissues and serum samples were collected and used to quantify levels of monoamines, hypothalamic-pituitary-adrenal axis and serum Estradiol. The status of neuronal cells in hippocampus 1 region was examined through hematoxylin-eosin staining, whereas expression of estrogen receptor α and β was detected by immunohistochemistry.

Results

Rats in the model group showed decreased mobility time, the disorder of neuronal cells in hippocampus 1 area, and decreased concentration of 5-hydroxytryptamine and dopamine in brain tissue, norepinephrine and estradiol in serum as well as estrogen receptor α and β expression. They also exhibited increased adrenocorticotropic hormone, corticosterone and corticotropin releasing hormone in serum. However, the treatment with processed Polygonatum cyrtonem Hua or fluoxetine reversed the above abnormalities.

Conclusion

The H group showed significant improvement in postpartum depression in rats, and processed Polygonatum cyrtonema Hua can be used as a developing drug for the prevention or treatment of depression.

D-ribose-L-cysteine exhibits restorative neurobehavioral functions through modulation of neurochemical activities and inhibition oxido-inflammatory perturbations in rats exposed to polychlorinated biphenyl

Polychlorinated biphenyl (PCB) is potentially harmful environmental toxicant causing cognitive decline with depressive features. PCB-induced behavioral deficits are associated with neurochemical dysfunctions, immune changes, and oxidative stress. This study investigated the neuroprotective effects of D-ribose-L-cysteine (DRLC), a neuroprotective precursor element of glutathione on PCB-induced neurobehavioral impairments. Following the initial 15 days of PCB (2 mg/kg) exposure to rats, DRLC (50 mg/kg) was given orally for an additional 15 days, from days 16 to 30. Animals were assessed for behavioral effect such as changes in locomotion, cognition, and depression. Oxidative/nitrergic stress markers; antioxidant regulatory proteins paraoxonase-1 (PON-1), heme oxygenase-1 (HO-1), nuclear factor erythroid 2-related factor 2 (Nfr2), NADPH oxidase-1 (NOX-1), NAD(P)H quinone oxidoreductase 1 (NQO1), and neuroinflammation (NF-kβ, and TNF-α); and neurochemical metabolizing enzymes (acetylcholinesterase (AChE), monoamine oxidase-A and -B (MAO-A, MAO-B)) were carried out. The PCB-induced decline in locomotion, cognitive performance, and depressive-like features were reversed by DRLC. More specifically, PCB-induced oxidative and nitrergic stress, typified by reduced levels GSH, CAT, and SOD, accompanied by elevated MDA and nitrite were attenuated by DRLC. Additionally, DRLC restored the neuroinflammatory milieu indicated by decreased NF-kβ and TNF-α levels toward normal. Hyperactivities of AChE, MAO-A, MAO-B, PON-1, and NOX-1 levels as well as Nfr2, NQO1, and PON-1 due to PCB exposure were mitigated by DLRC. Our results suggest DRLC as a prospective neurotherapeutic agent against PCB-induced neurobehavioral impairments such as cognitive deficit and depressive-like feature through antioxidative and anti-nitrergic stress, anti-neuroinflammation, inhibition of brain metabolizing enzymes, and normalization of neurochemical homeostasis.

Protective potential of naringenin and its nanoformulations in redox mechanisms of injury and disease

Increasing evidence suggests that elevated intracellular levels of reactive oxygen species (ROS) play a significant role in the pathogenesis of many diseases. Increased intracellular levels of ROS can lead to the oxidation of lipids, DNA, and proteins, contributing to cellular damage. Hence, the maintenance of redox hemostasis is essential. Naringenin (NAR) is a flavonoid included in the flavanones subcategory. Various pharmacological actions have been ascribable to this phytochemical composition, including antioxidant, anti-inflammatory, antibacterial, antiviral, antitumor, antiadipogenic, neuro-, and cardio-protective activities. This review focused on the underlying mechanism responsible for the antioxidative stress properties of NAR and its' nanoformulations. Several lines of in vitro and in vivo investigations suggest the effects of NAR and its nanoformulation on their target cells via modulating signaling pathways. These nanoformulations include nanoemulsion, nanocarriers, solid lipid nanoparticles (SLN), and nanomicelle. This review also highlights several beneficial health effects of NAR nanoformulations on human diseases including brain disorders, cancer, rheumatoid arthritis, and small intestine injuries. Employing nanoformulation can improve the pharmacokinetic properties of NAR and consequently efficiency by reducing its limitations, such as low bioavailability. The protective effects of NAR and its' nanoformulations against oxidative stress may be linked to the modulation of Nrf2-heme oxygenase-1, NO/cGMP/potassium channel, COX-2, NF-κB, AMPK/SIRT3, PI3K/Akt/mTOR, BDNF, NOX, and LOX-1 pathways. Understanding the mechanism behind the protective effects of NAR can facilitate drug development for the treatment of oxidative stress-related disorders.

Jobelyn® improves motor dysfunctions induced by haloperidol in mice via neuroprotective mechanisms relating to modulation of cAMP response-element binding protein and mitogen-activated protein kinase

The clinical efficacy of haloperidol in the treatment of psychosis has been limited by its tendency to cause parkinsonian-like motor disturbances such as bradykinesia, muscle rigidity and postural instability. Oxidative stress-evoked neuroinflammation has been implicated as the key neuropathological mechanism by which haloperidol induces loss of dopaminergic neurons and motor dysfunctions. This study was therefore designed to evaluate the effect of Jobelyn® (JB), an antioxidant supplement, on haloperidol-induced motor dysfunctions and underlying molecular mechanisms in male Swiss mice. The animals were distributed into 5 groups (n = 8), and treated orally with distilled water (control), haloperidol (1 mg/kg) alone or in combination with each dose of JB (10, 20 and 40 mg/kg), daily for 14 days. Thereafter, changes in motor functions were evaluated on day 14. Brain biomarkers of oxidative stress, proinflammatory cytokines (tumor necrosis factor-alpha and interleukin-6), cAMP response-element binding protein (CREB), mitogen-activated protein kinase (MAPK) and histomorphological changes were also investigated. Haloperidol induces postural instability, catalepsy and impaired locomotor activity, which were ameliorated by JB. Jobelyn® attenuated haloperidol-induced elevated brain levels of MDA, nitrite, proinflammatory cytokines and also boosted neuronal antioxidant profiles (GSH and catalase) of mice. It also restored the deregulated brain activities of CREB and MAPK, and reduced the histomorphological distortions as well as loss of viable neuronal cells in the striatum and prefrontal cortex of haloperidol-treated mice. These findings suggest possible benefits of JB as adjunctive remedy in mitigating parkinsonian-like adverse effects of haloperidol through modulation of CREB/MAPK activities and oxidative/inflammatory pathways.

Naringenin ameliorates aluminum toxicity-induced testicular dysfunctions in mice by suppressing oxidative stress and histopathological alterations

Environmental aluminum intoxication has shown increasingly alarming negative consequences on reproductive health. This needs mechanistic exploration and preventive management using medicines like herbal supplementation. The ameliorative effects of naringenin (NAR) against AlCl3-induced reproductive toxicity were thus evaluated in this study by assessing testicular dysfunction in albino male mice. A group of mice was treated with AlCl3 (10 mg/kg b.w./day) and then with NAR (10 mg/kg b.w./day) for a total of sixty-two days. Results show that treatment of AlCl3 significantly reduced the body weight and testis weight of mice. AlCl3 caused oxidative damage in mice as evidenced by an increase in the concentration of nitric oxide, advanced oxidation of protein product, protein carbonylation, and lipid peroxidation. Furthermore, diminished activity of antioxidant moieties included superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, reduced glutathione, and oxidized glutathione. Several histological changes, such as spermatogenic cell degeneration, germinal epithelium detachment, and structural abnormalities in seminiferous tubules, were observed in AlCl3-treated mice. Oral administration of NAR was found to restore body weight and testes weight and ameliorated reproductive dysfunctions. NAR decreased oxidative stress, replenished the antioxidant defense system, and improved histopathological alterations in the AlCl3-treated testes. Therefore, the present study suggests that the supplementation of NAR may be a beneficial strategy to mitigate AlCl3-induced reproductive toxicity and testicular dysfunction.

Nutritional, Antioxidant, Antimicrobial, and Anticholinesterase Properties of Phyllanthus emblica: A Study Supported by Spectroscopic and Computational Investigations

Dietary fruits and vegetables play a vital role as food and drugs and are the main sources of antioxidant defences against degenerative diseases, such as brain dysfunctions, cardiovascular diseases, immune system deteriorations, and cancers, brought on by oxidative damage. Phyllanthus emblica is a significant herbal remedy used in conventional medicine to recover lost strength and power. In this research, the potential value of Phyllanthus emblica as a food and drug is researched. The total phenolic, total flavonoid, and total tannin contents as well as the nutritional value, vitamin C, vitamin E, and mineral contents of different organs of P. emblica were evaluated. The antioxidant and antimicrobial activities of extracts and fractions of different organs of P. emblica were determined. A total of eleven flavonoids, simple phenolic, tannin-related phenolic, and tannin molecules were isolated from a hydroalcoholic extract of the leaves and fruits. The structures were identified by spectroscopic data and comparison with the literature values as gallic acid (1), naringenin 7-O-(6″-O-galloyl)-β-D-glucopyranoside (2), 3,3'-di-O-methyl ellagic acid-4'-O-β-d-glucopyranoside (3), 1-O-galloyl glycerol (4), 1,6-di-O-galloyl-β-d-glucopyranoside (5), flavogallonic acid bislactone (6), corilagin (7), ethyl gallate (8), urolithin M5 (9), (E)-p-coumaroyl-1-O-β-d-glucopyranoside (10), and 1,2,4,6-tetra-O-galloyl-β-d-glucopyranoside (11). Among them, compounds 3 and 10 are first isolated from the plant. Molecular docking was performed to investigate the comparative interactions between positive controls (galantamine and donepezil) and selected compounds utilizing acetylcholinesterase (4EY7) as a target receptor. Results exhibited the potency of these compounds against the target receptor. In summary, P. emblica has a wealth of minerals, vitamins C and E, and polyphenolic phytochemicals that may work together to treat infectious disease, prevent and/or treat oxidative-damage-related illnesses including Alzheimer's disease.

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.

Naringenin alleviate reproductive toxicity evoked by lead acetate via attenuation of sperm profile and biochemical alterations in male Wistar rat: Involvement of TGFβ/AKT/mTOR pathway

Exposure to Lead -causes testicular dysfunction through oxidative stress, inflammation, and apoptosis; however, naringenin (NGN) therapeutic impact against lead-evoked testicular dysfunction remains elusive. Herein, the point of the study was to examine the defensive impact of NGN on testicular dysfunction initiated by lead. Seventy-Two male Wistar rats were allotted into nine groups; control group, drug control groups, lead acetate group, as well as NGN treated groups (10, 25, and 50 mg/kg) respectively, given 5 days before lead acetate treatment. The result showed clearly the impact of lead on reduced sperm count, sperm motility as well as serum testosterone and LH levels. Additionally, it caused a significant rise in testicular inflammatory markers TNF-α, IL-1β, and TGFβ, effects that were accompanied by a reduction of AKT and mTOR levels. Lead acetate also caused degenerative changes in the testis, atrophy, and loss of spermatogenic series. Our findings revealed that NGN in a dose-dependent manner improved spermiotoxicity induced by lead acetate via restoration of the testicular function, preservation of spermatogenesis, halting inflammatory cytokines along with the enhancement of germ cell survival using upregulation of AKT/mTOR expressions. The present study discloses that NGN suppresses lead acetate toxicity that is involved in the antioxidant effect in a dose-dependent manner, besides its anti-inflammatory property.

Normalization of HPA Axis, Cholinergic Neurotransmission, and Inhibiting Brain Oxidative and Inflammatory Dynamics Are Associated with The Adaptogenic-like Effect of Rutin Against Psychosocial Defeat Stress

Social defeat stress (SDS) due to changes in biochemical functions has been implicated in the pathogenesis of affective and cognitive disorders. Employing pharmacological approach with adaptogens in the management and treatment of psychosocial stress is increasingly receiving scientific attention. In this study, we investigated the neuroprotective effect of rutin, a bioflavonoid with neuroprotective and anti-inflammatory functions on neurobehavioral and neuro-biochemical changes in mice exposed to SDS. Groups of mice named the intruder mice received normal saline (10 mL/kg), rutin (5, 10, and 20 mg/kg, i.p.), and ginseng (50 mg/kg, i.p.) daily for 14 days, and then followed by 10 min daily SDS (physical/psychological) exposures to aggressor mice from days 7-14. Investigations consisting of neurobehavioral (locomotion, memory, anxiety, and depression) phenotypes, neuro-biochemical (oxidative, nitrergic, cholinergic, and pro-inflammatory cytokines) levels in discrete brain regions, and hypothalamic-pituitary-adrenal (HPA) axis consisting adrenal weight, corticosterone, and glucose concentrations were assessed. Rutin restored the neurobehavioral deficits and reduced the activity of acetylcholinesterase in the brains. Adrenal hypertrophy, increased serum glucose and corticosterone levels were significantly attenuated by rutin. SDS-induced release of tumor necrosis factor-alpha and interleukin-6 in the striatum, prefrontal cortex, and hippocampus were also suppressed by rutin in a brain-region-dependent manner. Moreover, SDS-induced oxidative stress characterized by low antioxidants (glutathione, superoxide-dismutase, catalase) and lipid peroxidation and nitrergic stress were reversed by rutin in discrete brain regions. Collectively, our data suggest that rutin possesses an adoptogenic potential in mice exposed to SDS via normalization of HPA, oxidative/nitrergic, and neuroinflammatory inhibitions. Thus, may be adopted in the management of neuropsychiatric syndrome due to psychosocial stress.

Neurobiological mechanisms of mood disorders: Stress vulnerability and resilience

Stress is an important factor in the development of several human pathologies. The response of rodents and humans to stress depends on many factors; some people and rodents develop stress-related mood disorders, such as depression and anxiety in humans, depression-like and anxiety-like behavior in mice and rats, while others report no new psychological symptoms in response to chronic or acute stress, and are considered susceptible and resilient to stress, respectively. Resilience is defined as the ability to thrive in the face of adversity and is a learned process that can help protect against occupational stressors and mental illnesses. There is growing interest in the underlying mechanisms involved in resilience and vulnerability to depression caused by stress, and some studies have demonstrated that individual variability in the way animals and humans respond to stress depends on several mechanisms, such as oxidative stress, neuronal plasticity, immunology and genetic factors, among others not discussed in this review, this review provides a general overview about this mechanism.

Repeated social defeat stress exacerbates lipopolysaccharide-induced behavioural deficits in mice: ameliorative role of Chrysophyllum albidum fruit extract through anti-neuroinflammation, antioxidant and neurochemical balance

Development of neuropsychiatric disorder is associated with stress-related increase in pro-inflammatory cytokines. Chrysophyllum albidum fruit is an edible tropical fruit containing vitamins and phenolic compounds, well known for their anti-inflammatory and antioxidant activities. This study was designed to investigate the neuroprotective effect of C. albidum fruit extract (CAFE) on stress and lipopolysaccharide (LPS)-induced behavioral and neurochemical impairments in mice. Male Swiss mice were divided into 6 groups (n = 6). Groups 1-3 were orally treated daily for 14 days with normal saline (0.1 mL/10 g), CAFE (100 mg/kg) and Ferulic acid (FA, 10 mg/kg), and left in home cage as controls. Groups 4-6 were treated similarly but subjected to repeated social defeat (RSD) stress using the resident-intruder model from days 1-14. The RSD-animals were injected with LPS (125 µg/kg, i.p) 60 min after each RSD session from days 8-14. Neurobehavioral functions: locomotor, cognitive and anxiety-like behaviors were assessed 24 h after the last treatment. Pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α), dopamine, acetylcholinesterase, glutamic acid decarboxylase (GAD), malondialdehyde, nitrites, and reduced glutathione (GSH) were determined in brain tissue. CAFE significantly attenuated RSD and LPS-induced hypolocomotion, cognitive impairment and anxiety-like behavior when compared to the control. Treatment with CAFE also significantly reversed the negative effects of RSD and LPS on pro-inflammatory cytokines, dopamine, acetylcholinesterase, GAD, and oxidative-nitrosative stress levels. The findings clearly indicated that Chrysophyllum albidum fruit demonstrated neuroprotective effects and can play a key role in mitigating against chronic stress and inflammation linked to neuropsychiatric disorders.

Amelioration of Scopolamine-Induced Cognitive Dysfunction in Experimental Mice Using the Medicinal Plant Salvia moorcroftiana

Salvia moorcroftiana is medicinally used in various parts of the world to treat a number of diseases. In the literature, the antiamnesic activity of this plant has not yet been reported. Therefore, the current study was aimed at evaluating the in vivo antiamnesic (scopolamine-induced) potential of Salvia moorcroftiana. The major phytochemical groups such as total phenolic (TPC), total tannin (TTC), and total flavonoid content (TFC) in methanolic extract (SlMo-Crd) and subsequent fractions of Salvia moorcroftiana were quantified using standard methods. The in vitro anticholinesterase (against butyryl cholinesterase; BChE and acetylcholinesterase; AChE) and antioxidant (against 2,2-diphenyl-1-picrylhydrazyl; DPPH and 2,2′-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid); ABTS free radicals) potentials of crude (SIMO-Crd) extract and fractions (hexane; SlMo-Hex, chloroform; SlMo-Chl, ethyl acetate; SlMo-Et) were also determined. The SlMo-Crd at doses of 100 and 200 mg/kg body weight compared to fractions of 75 and 150 mg/kg body weight (which were 1/10th of the highest dose tested in acute toxicity tests) were evaluated for their memory enhancement and learning behavior in normal and scopolamine-induced mental dysfunction in mice using behavioral memory tests such as the Y-maze test and novel object recognition test (NORT). Moreover, the samples were further evaluated for acetylcholine contents and biochemical markers such as MDA (malondialdehyde), SOD (superoxide dismutase), CAT (catalase), and GSH (glutathione peroxidase) levels. The maximum TPC with a value of 114.81 ± 1.15 mg GAE/g, TTC with a value of 106.79 ± 1.07 mg GAE/g, and TFC with a value of 194.29 ± 0.83 mg RE/g were recorded for the SlMo-Chl fraction. Against the DPPH free radical, the methanolic extract exhibited an IC₅₀ value of 95.29 ± 1.06 µg/mL whereas, among the fractions, the best activity was observed for the SlMo-Chl fraction with an IC₅₀ of 75.02 ± 0.91 µg/mL, followed by SlMoS-Et with an IC₅₀ value of 88.71 ± 0.87 µg/mL. Among the extracts, the SlMo-Chl and SlMo-Et fractions inverted the amnesic effects of scopolamine in mice effectively. Additionally, the SlMo-Chl and SIMO-Et fractions considerably enhanced the percent spontaneous alteration performance in the Y-maze test with values of 65.18 ± 2.61/69.51 ± 2.71 and 54.92 ± 2.49/60.41 ± 2.69, respectively, for the tested doses. The discrimination index (DI) in experimental mice was considerably enhanced by the SlMo-Chl in the NORT with values of 59.81 ± 1.21/61.22 ± 1.31% DI correspondingly for the tested doses, as mentioned above, followed by the SlMo-Et extract. The selected plant in the form of extracts ameliorated the effects of amnesia in mice and could, therefore, be used as a therapy for amnesia; however, this is subject to further exploration in other animal models and the isolation of the responsible compounds.

Potential Therapeutic Benefits of Honey in Neurological Disorders: The Role of Polyphenols

Honey is the principal premier product of beekeeping familiar to Homo for centuries. In every geological era and culture, evidence can be traced to the potential usefulness of honey in several ailments. With the advent of recent scientific approaches, honey has been proclaimed as a potent complementary and alternative medicine for the management and treatment of several maladies including various neurological disorders such as Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, and multiple sclerosis, etc. In the literature archive, oxidative stress and the deprivation of antioxidants are believed to be the paramount cause of many of these neuropathies. Since different types of honey are abundant with certain antioxidants, primarily in the form of diverse polyphenols, honey is undoubtedly a strong pharmaceutic candidate against multiple neurological diseases. In this review, we have indexed and comprehended the involved mechanisms of various constituent polyphenols including different phenolic acids, flavonoids, and other phytochemicals that manifest multiple antioxidant effects in various neurological disorders. All these mechanistic interpretations of the nutritious components of honey explain and justify the potential recommendation of sweet nectar in ameliorating the burden of neurological disorders that have significantly increased across the world in the last few decades.

Medicinal plants used in traditional Mayan medicine for the treatment of central nervous system disorders: An overview

ETHNOPHARMACOLOGICAL RELEVANCE

For thousands of years, different cultural groups have used and transformed natural resources for medicinal purposes focused on psychological or neurological conditions. Some of these are recognized as central nervous system (CNS) disorders and diseases, whereas other ethnopsychiatric interpretations are explained in culture-specific terms. In traditional Mayan medicine, several herbs have been part of treatments and rituals focused on cultural and ethnomedical concepts.

AIM OF REVIEW

This study aims to provide a comprehensive overview of the medicinal plants used in Mesoamerica by traditional healers and Mayan groups to CNS disorders and associate the traditional use with demonstrated pharmacological evidence to establish a solid foundation for directing future research.

METHODS

A systematic search for primary sources of plant use reports for traditional CNS-related remedies of Mesoamerica were obtained from library catalogs, thesis and scientific databases (PubMed, Scopus, Google Scholar; and Science Direct), and entered in a database with data analyzed in terms of the usage frequency, use by ethnic groups, plant endemism, and pharmacological investigation.

RESULTS

A total of 155 plants used for ethnopsychiatric conditions in Mesoamerica by Mayan groups were found, encompassing 127 native species. Of these, only 49 native species have reported in vitro or in vivo pharmacological analyses. The most commonly reported ethnopsychiatric conditions are related to anxiety, depression, memory loss, epilepsy, and insomnia. The extent of the scientific evidence available to understand the pharmacological application for their use against CNS disorders varied between different plant species, with the most prominent evidence shown by Annona cherimola, Justicia pectoralis, J. spicigera, Mimosa pudica, Persea americana, Petiveria alliacea, Piper amalago, Psidium guajava, Tagetes erecta and T. lucida.

CONCLUSION

Available pharmacological data suggest that different plant species used in traditional Mayan medicine may target the CNS, mainly related to GABA, serotonin, acetylcholine, or neuroprotective pathways. However, more research is required, given the limited data regarding mechanism of action at the preclinical in vivo level, identification of active compounds, scarce number of clinical studies, and the dearth of peer-reviewed studies.

In Silico Design of Dual-Binding Site Anti-Cholinesterase Phytochemical Heterodimers as Treatment Options for Alzheimer’s Disease

The number of patients with neurodegenerative diseases, particularly Alzheimer’s disease (AD), continues to grow yearly. Cholinesterase inhibitors (ChEIs) represent the first-line symptomatic drug treatment for mild-to-moderate AD; however, there is an unmet need to produce ChEIs with improved efficacy and reduced side effects. Herein, phytochemicals with reported anti-acetylcholinesterase (AChE) activity were ranked in silico for their anti-AChE potential. Ligands with a similar or higher binding affinity to AChE than galantamine were then selected for the design of novel dual-binding site heterodimeric drugs. In silico molecular docking of heterodimers with the target enzymes, AChE and butyrylcholinesterase (BuChE), were performed, and anti-cholinesterase binding affinities were compared with donepezil. Drug-likeliness properties and toxicity of the heterodimers were assessed using the SwissADME and ProTox-II webservers. Nine phytochemicals displayed similar or higher binding affinities to AChE than galantamine: sanguinarine > huperzine A > chelerythrine > yohimbine > berberine > berberastine > naringenin > akuammicine > carvone. Eleven heterodimeric ligands were designed with phytochemicals separated by four- or five-carbon alkyl-linkers. All heterodimers were theoretically potent AChE and BuChE dual-binding site inhibitors, with the highest affinity achieved with huperzine-4C-naringenin, which displayed 34% and 26% improved affinity to AChE and BuChE, respectively, then the potent ChEI drug, donepezil. Computational pharmacokinetic and pharmacodynamic screening suggested that phytochemical heterodimers would display useful gastrointestinal absorption and with relatively low predicted toxicity. Collectively, the present study suggests that phytochemicals could be garnered for the provision of novel ChEIs with enhanced drug efficacy and low toxicity.

Dietary Naringenin Preserves Insulin Sensitivity and Grip Strength and Attenuates Inflammation but Accelerates Weight Loss in a Mouse Model of Cancer Cachexia

SCOPE

Cancer cachexia is characterized by the loss of skeletal muscle resulting in functional impairment, reduced quality of life and mortality. Naringenin, a flavonoid found in citrus fruits, improves insulin sensitivity and reduces inflammation and tumor growth in preclinical models. Therefore, the study hypothesizes that dietary supplementation of naringenin will improve insulin sensitivity, decrease inflammation, slow body weight loss, and delay tumor growth in a mouse model of cancer cachexia.

METHODS AND RESULTS

Mice are fed 2 wt% dietary naringenin before and during initiation of cancer cachexia using inoculated adenocarcinoma-26 cells (C-26). Food intake, body weight, body composition, muscle function, insulin tolerance, and inflammatory status are assessed. Although naringenin-fed tumor-bearing mice exhibit reductions in body weight and food intake earlier than control diet-fed tumor-bearing mice, dietary naringenin is protective against loss of muscle strength, and attenuates the onset of insulin resistance and markers of inflammation.

CONCLUSIONS

Dietary supplementation of naringenin improves multiple aspects of metabolic disturbance and inflammation during cancer cachexia progression in [C-26 tumor-bearing] mice. However, the acceleration of anorexia and weight loss is also observed. These findings emphasize the link between inflammation and insulin resistance as a basis for understanding their roles in the pathogenesis of cancer cachexia.

Phenolic compounds that cross the blood-brain barrier exert positive health effects as central nervous system antioxidants

The blood-brain barrier (BBB) is a physical structure whose main function is to strictly regulate access to circulating compounds into the central nervous system (CNS). Vegetable-derived phenolic compounds have been widely studied, with numerous epidemiologic and interventional studies confirming their health-related bioactivities across multiple cells, organs and models. Phenolics are non-essential xenobiotics, and should theoretically be unable to cross the BBB. The present work summarizes current experimental evidence that reveals that not only are phenolic compounds able to cross the BBB and bioaccumulate in the brain, but there is some stereoselectivity, which suggests the presence of specific transporters that allow them to reach the brain. Some molecules cross the BBB intact, while others do so only after being biotransformed or metabolized elsewhere. Once inside the CNS, they prevent or counter oxidative stress, which maintains the molecular, cellular, structural and functional integrity of the brain, and subsequently, overall human health.

Mini-review: Brain energy metabolism and its role in animal models of depression, bipolar disorder, schizophrenia and autism

Mitochondria are cellular organelles essential for energy metabolism and antioxidant defense. Mitochondrial impairment is implicated in many psychiatric disorders, including depression, bipolar disorder, schizophrenia, and autism. To characterize and eventually find effective treatments of bioenergetic impairment in psychiatric disease, researchers find animal models indispensable. The present review focuses on brain energetics in several environmental, genetic, drug-induced, and surgery-induced animal models of depression, bipolar disorder, schizophrenia, and autism. Most reported deficits included decreased activity in the electron transport chain, increased oxidative damage, decreased antioxidant defense, decreased ATP levels, and decreased mitochondrial potential. Models of depression, bipolar disorder, schizophrenia, and autism shared many bioenergetic deficits. This is in concordance with the absence of a disease-specific brain energy phenotype in human patients. Unfortunately, due to the absence of null results in examined literature, indicative of reporting bias, we refrain from making generalized conclusions. Present review can be a valuable tool for comparing current findings, generating more targeted hypotheses, and selecting fitting models for further preclinical research.

Improvement of cognitive function in mice by Citrus reticulata var. kinnow via modulation of central cholinergic system and oxidative stress

Memory disorders are a result of a number of factors, of which elevated brain oxidative stress and acetylcholinesterase (AChE) activity are significant hallmarks. A number of Citrus species have cognition-enhancing capacity mediated by their antioxidant and anti-cholinesterase activities. This study was designed to assess the cognitive-enhancing, antioxidant and anticholinesterase potentials of Citrus reticulata var. kinnow (CR) leaf extracts. CR extracts were examined by bioactivity guided fractionation using in-vitro DPPH and Ellman assays to determine antioxidant and AChE inhibitory capacity. The most active component was further evaluated for memory improvement effects using mouse model of scopolamine induced amnesia. Passive shock avoidance test and elevated plus maze test were employed to determine cognitive functions while brain biochemical parameters were measured to establish the neuroprotective mechanism. The methanol extract (ME) showed marked AChE inhibitory and antioxidant activities, therefore, it was fractionated. Comparative analysis of all obtained fractions revealed that ethylacetate fraction (EAF) was most active. Both ME and EAF improved cognitive dysfunction caused by scopolamine in mice by reducing TBARS levels and brain AChE activity. TLC densitometric studies showed appreciable levels of naringenin in ME (0.32 % w/w) and EAF (1.14 % w/w). The observed memory enhancement effects of ME and EAF could be attributed to their ability to inhibit AChE activity and antioxidant effects due to presence of flavonoids.

Naringenin Ameliorates Chronic Sleep Deprivation-Induced Pain via Sirtuin1 Inhibition

Growing experimental evidences have suggested the reciprocal correlation between sleep deprivation and pain. Inflammation and oxidative stress are among the key pathways underlying this correlation. Therefore, the present study was aimed to assess the effect of antioxidant and anti-inflammatory compound naringenin (NGN) against chronic sleep deprivation (CSD)-induced mechanical and thermal hyperalgesia in female Swiss albino mice. In this study, mice were chronically sleep-deprived for 8 h a day for five days a week with the weekend as a free sleep period and continued for nine weeks using a modified multiple platform method. The pain behavioral tests were conducted at the end of the fourth week to assess the development of hyperalgesia followed by the administration of NGN and a combination of NGN with Sirtinol (SIR, a sirtuin1 inhibitor) till the end of the study. After nine weeks, pain behavioral tests, along with oxidative stress and inflammatory parameters in cortex and striatum, were assessed. Results indicated that CSD-induced hyperalgesia in mice accompanied by increased oxidative stress and inflammatory markers in cortex and striatum of the brain. NGN combatted the hyperalgesic response and also decreased levels of oxidative stress and inflammatory markers. Furthermore, the pharmacological effect of NGN was mitigated with SIR. Thus, the findings of the present study reveal that NGN is acting via sirtuin1 to exert its antinociceptive activity against CSD-induced hyperalgesia.

Potential Herb-Drug Interactions in the Management of Age-Related Cognitive Dysfunction

Late-life mild cognitive impairment and dementia represent a significant burden on healthcare systems and a unique challenge to medicine due to the currently limited treatment options. Plant phytochemicals have been considered in alternative, or complementary, prevention and treatment strategies. Herbals are consumed as such, or as food supplements, whose consumption has recently increased. However, these products are not exempt from adverse effects and pharmacological interactions, presenting a special risk in aged, polymedicated individuals. Understanding pharmacokinetic and pharmacodynamic interactions is warranted to avoid undesirable adverse drug reactions, which may result in unwanted side-effects or therapeutic failure. The present study reviews the potential interactions between selected bioactive compounds (170) used by seniors for cognitive enhancement and representative drugs of 10 pharmacotherapeutic classes commonly prescribed to the middle-aged adults, often multimorbid and polymedicated, to anticipate and prevent risks arising from their co-administration. A literature review was conducted to identify mutual targets affected (inhibition/induction/substrate), the frequency of which was taken as a measure of potential interaction. Although a limited number of drugs were studied, from this work, interaction with other drugs affecting the same targets may be anticipated and prevented, constituting a valuable tool for healthcare professionals in clinical practice.

Naringenin improves depressive- and anxiety-like behaviors in mice exposed to repeated hypoxic stress through modulation of oxido-inflammatory mediators and NF-kB/BDNF expressions

Oxidative and inflammatory signaling pathways have been identified as important targets for mitigating hypoxic stress-induced neurological complications. Thus, the effects of naringenin, a potent antioxidant, anti-inflammatory and neuroprotective bioflavonoid on hypoxic stress-induced depressive-like and anxiety-related behaviors in mice, and the underlying molecular mechanisms were evaluated in this study. Thirty-five male Swiss mice were distributed into 5 groups (n = 7). Mice in group I (non-stress control) and group 2 (stress-control) both had vehicle (5 % DMSO), while groups 3-5 received naringenin (10, 25 and 50 mg/kg), intraperitonally. Thirty minutes later, mice in groups 2-5 were subjected to 15 min hypoxic stress, daily for 14 days. Locomotor activity, anxiety and depression were evaluated on day 15. The mice brains were processed for malondialdehyde, glutathione, superoxide-dismutase (SOD), catalase, tumor necrosis factor-alpha (TNF-α) and interleukin-1β assays. The serum corticosterone concentration and expressions of the brain immunopositive cells of inducible nitric oxide synthase (iNOS), nuclear factor kappa-B (NF-kB) and brain derived neurotrophic factor (BDNF) as well as histomorphological changes of the amygdala were also determined. Naringenin (25-50 mg/kg) ameliorated the hypolocomotion, depressive- and anxiety-like behaviors in hypoxic mice. The increased brain contents of malondialdehyde, TNF-α, interleukin-1β, and decreased antioxidant (glutathione and SOD) status were attenuated by naringenin. Naringenin (10 mg/kg) increases BDNF expression but did not significantly (p < 0.05) alter corticosterone and catalase contents. The increased expressions of iNOS and NF-kB as well as loss of amygdala neuronal cells were reduced by naringenin (10 mg/kg). Overall, these findings suggest that naringenin improves depressive- and anxiety-like behaviors in mice exposed to hypoxic stress by modulating oxido-inflammatory insults and NF-kB/BDNF expressions.

Oxidative Stress at the Crossroads of Aging, Stroke and Depression

Epidemiologic studies have shown that in the aging society, a person dies from stroke every 3 minutes and 42 seconds, and vast numbers of people experience depression around the globe. The high prevalence and disability rates of stroke and depression introduce enormous challenges to public health. Accumulating evidence reveals that stroke is tightly associated with depression, and both diseases are linked to oxidative stress (OS). This review summarizes the mechanisms of OS and OS-mediated pathological processes, such as inflammation, apoptosis, and the microbial-gut-brain axis in stroke and depression. Pathological changes can lead to neuronal cell death, neurological deficits, and brain injury through DNA damage and the oxidation of lipids and proteins, which exacerbate the development of these two disorders. Additionally, aging accelerates the progression of stroke and depression by overactive OS and reduced antioxidant defenses. This review also discusses the efficacy and safety of several antioxidants and antidepressants in stroke and depression. Herein, we propose a crosstalk between OS, aging, stroke, and depression, and provide potential therapeutic strategies for the treatment of stroke and depression.

Metabolic Impact of Flavonoids Consumption in Obesity: From Central to Peripheral

The prevention and treatment of obesity is primary based on the follow-up of a healthy lifestyle, which includes a healthy diet with an important presence of bioactive compounds such as polyphenols. For many years, the health benefits of polyphenols have been attributed to their anti-oxidant capacity as free radical scavengers. More recently it has been described that polyphenols activate other cell-signaling pathways that are not related to ROS production but rather involved in metabolic regulation. In this review, we have summarized the current knowledge in this field by focusing on the metabolic effects of flavonoids. Flavonoids are widely distributed in the plant kingdom where they are used for growing and defensing. They are structurally characterized by two benzene rings and a heterocyclic pyrone ring and based on the oxidation and saturation status of the heterocyclic ring flavonoids are grouped in seven different subclasses. The present work is focused on describing the molecular mechanisms underlying the metabolic impact of flavonoids in obesity and obesity-related diseases. We described the effects of each group of flavonoids in liver, white and brown adipose tissue and central nervous system and the metabolic and signaling pathways involved on them.

Naringin Confers Protection against Psychosocial Defeat Stress-Induced Neurobehavioral Deficits in Mice: Involvement of Glutamic Acid Decarboxylase Isoform-67, Oxido-Nitrergic Stress, and Neuroinflammatory Mechanisms

Psychosocial stress has been widely reported to contribute to psychiatric disturbances. Perturbations in the enzymes of GABAergic and cholinergic systems have been implicated as precursors in different stress-related neuropsychiatric diseases. Targeting glutamic acid decarboxylase-67 kDa (GAD67) and acetylcholinesterase (AChE) via oxidative, nitrergic, and neuroinflammatory mechanisms have been recognized as prospective strategies for the prevention of psychosocial stress-induced behavioral impairments. Naringin, a neuro-active flavonoid compound isolated from citrus fruits, has been shown to produce memory-enhancing, antiepileptic, antidepressant, and anti-inflammatory activities similarly to ginseng, a very potent adaptogen. In this communication, we assessed the effect of naringin on social-defeat stress (SDS)-induced behavioral, GABAergic, cholinergic, oxidative, nitrergic, and neuroinflammatory changes in mice using the resident-intruder paradigm. The intruder male mice were culled into six groups. Groups 1 and 2 (normal- and SDS-controls) received sterile saline, groups 3-5 were given naringin (25-100 mg/kg, i.p.) whereas group 6 had ginseng (50 mg/kg, i.p.) daily for 14 days, but followed by 10 min SDS (physical and psychological) exposure to groups 2-6 with aggressor-resident mice. Behavioral effects using Y-maze, elevated-plus maze, sociability, and tail-suspension tests were assessed on day 14. GAD67, AChE enzymes, and biomarkers of oxidative, nitrergic, and neuroinflammatory changes were assayed in the striatum, prefrontal cortex, and hippocampus. Naringin and ginseng reversed all SDS-induced behavioral impairments. Naringin increased the levels of GAD67 and decreased AChE activities in the striatum, prefrontal cortex, and hippocampus. Furthermore, naringin reduced pro-inflammatory cytokines (TNF-α, IL-6), malondialdehyde, nitrite concentrations, and increased glutathione levels in a region-dependent manner. Our study suggests that naringin attenuated SDS-induced behavioral endophenotypes of neuropsychiatric disease through increased GAD67 synthesis, inhibition of AChE activity, oxidative, nitrergic stress, and neuroinflammatory processes in stress-sensitive brain regions.

Cymbopogon citratus aqueous leaf extract attenuates neurobehavioral and biochemical changes induced by social defeat stress in mice

Objective

Psychosocial stress has been implicated in the genesis of psychiatric disorders such as memory deficits, depression, anxiety and addiction. Aqueous leaf extract of Cymbopogon citratus (CYC) otherwise known as lemongrass tea has antidepressant, anxiolytic and anti-amnesic effects in rodents. This study was designed to evaluate if C. citratus could reverse the neurobehavioral and biochemical derangements induced by social defeat stress (SDS) in the resident/intruder paradigm.

Methods

Intruder male mice were divided into five groups (n = 7): group 1 received saline (10 mL/kg, p.o.; non-stress control), group 2 also received saline (10 mL/kg, p.o.; SDS control) while groups 3–5 had C. citratus (50, 100 and 200 mg/kg, p.o.) daily for 14 d. The SDS was carried out 30 min after each treatment from day 7 to day 14 by exposing each intruder mouse in groups 2–5 to a 10 min confrontation in the home cage of an aggressive resident counterpart. The neurobehavioral features (spontaneous motor activity-SMA, anxiety, memory, social avoidance and depression were then evaluated. The concentrations of nitrite, malondialdehyde and glutathione as well as acetylcholinesterase activity in the brain tissues were also determined.

Results

C. citratus (50, 100 and 200 mg/kg) attenuated hypolocomotion, heightened anxiety, depressive-like symptom, memory deficit and social avoidance induced by SDS. The altered levels of oxidative stress and acetyl-cholinesterase in SDS-mice were positively modulated by C. citratus.

Conclusion

The results of this study suggest that C. citratus might mitigate psychosocial stress-induced neurologic diseases in susceptible individuals.

Repeated psychosocial stress causes glutamic acid decarboxylase isoform-67, oxidative-Nox-2 changes and neuroinflammation in mice: Prevention by treatment with a neuroactive flavonoid, morin

Psychosocial stress and biological predispositions are linked to mood and personality disorders related to psychiatric behaviors. Targeting neuroinflammation and oxidative stress has been recognized as a potential strategy for the prevention of psychosocial stress-induced psychiatric disorders. Morin, a bioactive compound isolated from mulberry leaf has been shown to produce antiamnesic, antipsychotic and anti-inflammatory effects relative to ginseng, a well-known adaptogen. Hence, the present study investigated the effect of morin on social-defeat stress (SDS)-induced behavioral, neurochemical, neuroimmune and neurooxidative changes in mice using intruder-resident paradigm. The intruder male mice were distributed into 6 groups (n = 10). Groups 1 (normal-control) and 2 (SDS-control) received normal saline, groups 3-5 had morin (25-100 mg/kg) while group 6 received ginseng (50 mg/kg) intraperitoneally daily for 14 days. Thirty minutes after treatment from days 7-14 onwards, mice in groups 2-6 were exposed to SDS for 10 min physical and psychological confrontations respectively with aggressive-resident mice. Neurobehavioral effects (locomotor activity, cognitive performance, anxiety- and depressive-like behavior) were assessed on day 14. Biomarkers of oxidative/nitrergic stress and neuroinflammation; acetylcholinesterase (AChE) and glutamic-acid decarboxylase-67 (GAD₆₇) were measured in the striatum, prefrontal-cortex and hippocampus. Behavioral deficits induced by SDS were attenuated by morin and ginseng. Both morin and ginseng decreasedmalondialdehyde, nitrite levels and increased glutathione concentrations in the brain regions. They also reduced inflammatory mediators (TNF-α, IL-6, COX-2 and NF-κB), AChE activity and Nox-2 expression in the specific brain regions. However, morin increased the levels of GAD₆₇ in the striatum, prefrontal-cortex and hippocampus in contrast to ginseng. Our results suggest that morin mitigates SDS-induced neurobehavioral deficits through enhancement of GAD₆₇, inhibition of AChE activity, oxidative stress, Nox-2 and neuroinflammatory pathways.

Oxidation-reduction mechanisms in psychiatric disorders: A novel target for pharmacological intervention

While neurotransmitter dysfunction represents a key component in mental illnesses, there is now a wide agreement for a central pathophysiological hub that includes hormones, neuroinflammation, redox mechanisms as well as oxidative stress. With respect to oxidation-reduction (redox) mechanisms, preclinical and clinical evidence suggests that an imbalance in the pro/anti-oxidative homeostasis toward the increased production of substances with oxidizing potential may contribute to the etiology and manifestation of different psychiatric disorders. The substantial and continous demand for energy renders the brain highly susceptible to disturbances in its energy supply, especially following exposure to stressful events, which may lead to overproduction of reactive oxygen and nitrogen species under conditions of perturbed antioxidant defenses. This will eventually induce different molecular alterations, including extensive protein and lipid peroxidation, increased blood-brain barrier permeability and neuroinflammation, which may contribute to the changes in brain function and morphology observed in mental illnesses. This view may also reconcile different key concepts for psychiatric disorders, such as the neurodevelopmental origin of these diseases, as well as the vulnerability of selective cellular populations that are critical for specific functional abnormalities. The possibility to pharmacologically modulate the redox system is receiving increasing interest as a novel therapeutic strategy to counteract the detrimental effects of the unbalance in brain oxidative mechanisms. This review will describe the main mechanisms and mediators of the redox system and will examine the alterations of oxidative stress found in animal models of psychiatric disorders as well as in patients suffering from mental illnesses, such as schizophrenia and major depressive disorder. In addition, it will discuss studies that examined the effects of psychotropic drugs, including antipsychotics and antidepressants, on the oxidative balance as well as studies that investigated the effectiveness of a direct modulation of oxidative mechanisms in counteracting the behavioral and functional alterations associated with psychiatric disorders, which supports the promising role of the redox system as a novel therapeutic target for the improved treatment of brain disorders.

Combined Treatment with Two Water Extracts of Eleutherococcus senticosus Leaf and Rhizome of Drynaria fortunei Enhances Cognitive Function: A Placebo-Controlled, Randomized, Double-Blind Study in Healthy Adults

We previously found that the water extract of Eleutherococcus senticosus leaves (ES extract) enhanced cognitive function in normal mice. Our study also revealed that the water extract of rhizomes of Drynaria fortunei (DR extract) enhanced memory function in Alzheimer’s disease model mice. In addition, our previous experiments suggested that a combined treatment of ES and DR extracts synergistically improved memory and anti-stress response in mice. Although those two botanical extracts are expected to be beneficial for neuropsychological function, no clinical data has ever been reported. Therefore, we performed a placebo-controlled, randomized, double-blind study to evaluate cognitive enhancement and anti-stress effects by the intake of a combined extract in healthy volunteers. The intake period was 12 weeks. The Japanese version of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) test was used for neurocognitive assessment. The combined treatment of ES and DR extracts significantly increased the figure recall subscore of RBANS (p = 0.045) in an intergroup comparison. Potentiation of language domain ((p = 0.040), semantic fluency (p = 0.021) and figure recall (p = 0.052) was shown by the extracts (in intragroup comparison). In anti-stress response, the anxiety/uncertainly score was improved by the extract in an intragroup comparison (p = 0.022). No adverse effects were observed. The combined treatment of ES and DR extracts appear to safely enhance a part of cognitive function in healthy adults.

Naringenin protects AlCl3/D-galactose induced neurotoxicity in rat model of AD via attenuation of acetylcholinesterase levels and inhibition of oxidative stress

Currently prescribed medications for the treatment of Alzheimer's disease (AD) that are based on acetylcholinesterase inhibition only offer symptomatic relief but do not provide protection against neurodegeneration. There appear to be an intense need for the development of therapeutic strategies that not only improve brain functions but also prevent neurodegeneration. The oxidative stress is one of the main causative factors of AD. Various antioxidants are being investigated to prevent neurodegeneration in AD. The objective of this study was to investigate the neuroprotective effects of naringenin (NAR) against AlCl3+D-gal induced AD-like symptoms in an animal model. Rats were orally pre-treated with NAR (50 mg/kg) for two weeks and then exposed to AlCl3+D-gal (150 mg/kg + 300 mg/kg) intraperitoneally for one week to develop AD-like symptoms. The standard drug, donepezil (DPZ) was used as a stimulator of cholinergic activity. Our results showed that NAR pre-treatment significantly protected AD-like behavioral disturbances in rats. In DPZ group, rats showed improved cognitive and cholinergic functions but the neuropsychiatric functions were not completely improved and showed marked histopathological alterations. However, NAR not only prevented AlCl3+D-gal induced AD-like symptoms but also significantly prevented neuropsychiatric dysfunctions in rats. Results of present study suggest that NAR may play a role in enhancing neuroprotective and cognition functions and it can potentially be considered as a neuroprotective compound for therapeutic management of AD in the future.

Immunoregulatory natural compounds in stress-induced depression: An alternative or an adjunct to conventional antidepressant therapy?

The interplay of chronic stress, neuroinflammation and altered immune reactivity has been shown to be important for the pathophysiology of brain disorders such as schizophrenia, depressive disorders and post-traumatic stress disorder. This immuno-inflammatory theory has been extensively studied in the past three decades leading to the formation of the integrative discipline of psychoneuroimmunology. Targeting of the central nervous system by conventional pharmacotherapeutic methods is mainly through modulation of neuroendocrine systems such as the dopaminergic, GABA-ergic, adrenergic and serotoninergic systems. In recent years an increasing number of both experimental and clinical studies have shown that antidepressants can affect the immune system by reducing the production of pro-inflammatory cytokines such as IL-1β, IL-6 and TNF-α. However, due to the serious adverse effects accompanying the chronic administration of psychoactive drugs there is a continuous need to produce novel therapeutics that are both potent and safe. The present review aims to summarize the current knowledge in the field of psychoneuroimmunology and to delineate the main interactions between stress, inflammation, immunity and the brain. Additionally, this paper explores the use of plant-derived molecules that display a strong anti-stress effect and simultaneously modulate the immune response as an alternative or adjuvant to classical antidepressant drugs.

Possible neuroprotective mechanisms of action involved in the neurobehavioral property of naringin in mice

Flavonoids are naturally occurring bioactive phytochemical metabolites widely known to prevent and suppress several human diseases, and are important sources of therapeutic compounds from plants. Evidence derived from previous studies suggests that naringin, a neuroactive flavonoid possess functional beneficial neurobehavioral effects including anxiolytic, antidepressant and memory enhancing properties. However, literature search revealed that no studies have been carried out to evaluate the possible biochemical mechanisms involved in the neurobehavioral property of naringin alone following repeated treatment. Hence, this study was designed to evaluate the possible neuro-biochemical mechanisms involved in the neurobehavioral property of naringin following repeated administration in mice. The effects of naringin (2.5, 5 and 10 mg/kg), diazepam (2 mg/kg), imipramine (15 mg/kg) and donepezil (1 mg/kg) or vehicle on neurobehavioral and biochemical effects were evaluated in mice following repeated intraperitoneal injection for 7 consecutive days. Neurobehavioral activities consisting of open-field (locomotor), elevated-plus maze (anxiolytic), forced swim and social interaction (antidepressant and social preference), and Y-maze (memory enhancing) tests were assessed. Thereafter, brains levels of biomarkers of oxidative, nitrosative and cholinergic parameters were determined. Repeated treatment with naringin produced increased locomotor activity, and demonstrated antidepressant-like effects evidenced by decreased immobility time in forced swim test and increased % social preference in the social interaction test relative to controls. Also, naringin induced anxiolytic-like effect and increased cognitive performance in mice. Mechanistically, naringin significantly increased the activities of superoxide dismutase and catalase, and glutathione concentration relative to vehicle-controls. However, naringin significantly decreased malondialdehyde and nitrite contents, and reduced brain acetylcholinesterase activity in mice brains in a significant manner relative to controls. Taken together, these findings suggest that treatment with naringin might be useful to produce functional behavioral effects via mechanisms related to enhancement of cholinergic transmission, antioxidant defense systems, inhibition of lipid peroxidation and nitrosative processes.