Neuroprotective effects of the ethanol stem bark extracts of Terminalia ivorensis in ketamine-induced schizophrenia-like behaviors and oxidative damage in mice

NMDA receptor modulation by Esculetin: Investigating behavioral, biochemical and neurochemical effects in schizophrenic mice model

Schizophrenia, a global mental health disorder affecting approximately 1 % of the population, is characterized by neurotransmitter dysregulation, particularly dopamine, serotonin, and glutamate. Current antipsychotic therapies, despite their efficacy, are accompanied by adverse effects, which has motivated researchers to investigate more secure substitutes. This study examines the potential antipsychotic effects of esculetin, a natural coumarin derivative recognized for its wide-ranging pharmacological activities (anti-inflammatory, antioxidant, anti-pathogenic, anticancer, and neuroprotective), in animal model of schizophrenia induced by ketamine. In order to induce disease, acute and chronic ketamine administration was performed on Swiss albino mice, supplemented with esculetin (as the test substance) and clozapine (as the reference standard). Behavioral studies and biochemical assays were performed to evaluate positive, negative, and cognitive symptoms of schizophrenia, as well as antioxidant and oxidant levels in various brain regions. Esculetin demonstrated significant improvements in behavioral symptoms, attenuated oxidative stress and neuroinflammation, and modulated neurotransmitter levels. Afterwards, ELISA was performed to evaluate levels of schizophrenia biomarkers AChE, BDNF. Moreover, proinflammatory cytokines (IL-6 and TNF-α) and NF-κB were also determined. Histopathological parameters of under study brain parts i.e., hippocampus, cortex and striata were also assessed. Esculetin and clozapine significantly (***p < 0.0001) altered ketamine induced behavioral symptoms and attenuated ketamine induced oxidative stress and neuroinflammation. Additionally, esculetin significantly (***p < 0.0001) altered neurotransmitter (dopamine, serotonin, glutamate) levels. ELISA analysis depicts ketamine reduced BDNF levels in hippocampus, cortex and striata while esculetin significantly (***p < 0.0001) increased BDNF levels in under study three parts of brain. Histopathological changes were seen in test groups. The findings of this study indicate that esculetin may have therapeutic potential in the treatment of schizophrenia induced by ketamine. As a result, esculetin may have the potential to be utilized as a treatment for schizophrenia.

Diosgenin alleviates alcohol-mediated escalation of social defeat stress and the neurobiological sequalae

RATIONALE

Emerging evidence indicates that persistent alcohol consumption escalates psychosocial trauma achieved by social defeat stress (SDS)-induced neurobiological changes and behavioral outcomes. Treatment with compounds with neuroprotective functions is believed to reverse ethanol (EtOH)-aggravated SDS-induced behavioral impairments.

OBJECTIVES

We investigated the outcomes of diosgenin treatment, a phytosteroidal sapogenin in mice co-exposed to repeated SDS and EtOH administration.

METHODS

During a period of 14 days, SDS male mice were repeatedly administered EtOH (20%, 10 mL/kg) orally from days 8-14 (n = 9). Within days 1-14, SDS mice fed with EtOH were simultaneously treated with diosgenin (25 and 50 mg/kg) or fluoxetine (10 mg/kg) by oral gavage. Locomotor, cognitive-, depressive-, and anxiety-like behaviors were assessed. Adrenal weight, serum glucose, and corticosterone levels were assayed. Brain markers of oxido-inflammatory, neurochemical levels, monoamine oxidase-B, and acetylcholinesterase activities were measured in the striatum, prefrontal cortex, and hippocampus.

RESULTS

The anxiety-like behavior, depression, low stress resilience, social, and spatial/non-spatial memory decline exhibited by SDS mice exposed to repeated EtOH administration were alleviated by diosgenin (25 and 50 mg/kg) and fluoxetine, illustrated by increased dopamine and serotonin concentrations and reduced monoamine oxidase-B and acetylcholinesterase activities in the prefrontal cortex, hippocampus, and striatum. Diosgenin attenuated SDS + EtOH interaction induced corticosterone release and adrenal hypertrophy, accompanied by reduced TNF-α, IL-6, malondialdehyde, and nitrite levels in the striatum, prefrontal cortex, and hippocampus. Diosgenin increased glutathione, superoxide dismutase, and catalase levels in SDS + EtOH-exposed mice.

CONCLUSIONS

Our data suggest that diosgenin reverses SDS + EtOH interaction-induced behavioral changes via normalization of hypothalamic-pituitary-adrenal axis, neurochemical neurotransmissions, and inhibition of oxidative and inflammatory mediators in mice brains.

Natural compounds for oxidative stress and neuroprotection in schizophrenia: composition, mechanisms, and therapeutic potential

OBJECTIVE

An imbalance between the generation of reactive oxygen species (ROS) and the body's antioxidant defense mechanisms is believed to be a critical factor in the development of schizophrenia (SCZ) like neurological illnesses. Understanding the roles of ROS in the development of SCZ and the potential activity of natural antioxidants against SCZ could lead to more effective therapeutic options for the prevention and treatment of the illness.

METHODS

SCZ is a mental disorder characterised by progressive impairments in working memory, attention, and executive functioning. In present investigation, we summarized the experimental findings for understanding the role of oxidative stress (OS) in the development of SCZ and the potential neuroprotective effects of natural antioxidants in the treatment of SCZ.

RESULTS

Current study supports the use of the mentioned antioxidant natural compounds as a potential therapeutic candidates for the treatment of OS mediated neurodegeneration in SCZ.

DISCUSSION

Elevated levels of harmful ROS and reduced antioxidant defense mechanisms are indicative of increased oxidative stress (OS), which is associated with SCZ. Previous research has shown that individuals with SCZ, including non-medicated, medicated, first-episode, and chronic patients, exhibit decreased levels of total antioxidants and GSH. Additionally, they have reduced antioxidant enzyme levels such as catalase (CAT), glutathione (GPx), and, superoxide dismutase (SOD) and lower serum levels of brain-derived neurotrophic factor (BDNF) in their brain tissue. The mentioned natural antioxidants may assist in reducing oxidative damage in individuals with SCZ and increasing BDNF expression in the brain, potentially improving cognitive function and learning ability.

Resveratrol plays neuroprotective role on ketamine-induced schizophrenia-like behaviors and oxidative damage in mice

This study aimed to determine effects of the resveratrol on ketamine-induced schizophrenia-like behaviors and oxidative damage in mice. Twenty-four male mice were allocated into four experimental groups as control, ketamine (20 mg/kg), resveratrol (80 mg/kg) and co-administration of the ketamine (20 mg/kg) + resveratrol (80 mg/kg). Mice were received resveratrol for 30 days and ketamine was used for an animal model of schizophrenia and was injected from days 16 to 30 of the study. After the drug administration was finished, schizophrenia-like behaviors were evaluated using object recognition test, tail suspension test, forced swimming test and open field test and brain malondialdehyde, glutathione peroxidase, superoxide dismutase and catalase levels were determined. According to the results, ketamine treatment significantly decreased body weight and pretreatment with resveratrol elevated body weight compared to ketamine group (P < 0.05). Ketamine treatment significantly decreased number of the cross in open field test and pretreatment with resveratrol improved i (P < 0.05). Immobility time in tail suspension and forced swimming tests increased in mice treated with ketamine (P < 0.05). Pretreatment with resveratrol diminished immobility time compared to ketamine group (P < 0.05). Ketamine significantly decreased memory deficits while pretreatment with resveratrol significantly reduced the memory deficits induced by ketamine (P < 0.05). Brain MDA increased in both cortical and sub-cortical area in ketamine treated mice while pretreatment with resveratrol decreased ketamine-induced elevation in MDA (P < 0.05). Ketamine significantly decreased brain SOD, GPx and CAT levels while pretreatment with resveratrol improved SOD, GPx and CAT levels (P < 0.05). Findings suggested resveratrol has neuroprotective effects against ketamine-induced behavioral deficits and oxidative damages.

Berberine improves inhibitory avoidance memory impairment of Toxoplasma gondii-infected rat model of ketamine-induced schizophrenia

BACKGROUND

Memory impairment caused by Toxoplasma gondii infection has been documented. Berberine (BRB) is well known for its enhancing effects on memory and has shown promising results. However, the impact of BRB on T. gondii infection and schizophrenia-induced consolidation and reconsolidation memory impairment is still unclear. Here; we examined the effect of BRB on the inhibitory avoidance (IA) memory consolidation and reconsolidation impairment induced by T. gondii infection, and ketamine (Ket) as a pharmacological model of schizophrenia. Also; the brain-derived neurotrophic factor (BDNF) levels in the medial prefrontal cortex (mPFC) and hippocampus were analyzed.

METHODS

Rats were infected with T. gondii RH strain or received Ket (30 mg/kg/day) intraperitoneally (i.p) for at least five consecutive days (as the model of schizophrenia). Then followed by oral administration with BRB (25 mg/kg/day) for five days. Finally, the IA memory retention test was examined 48 post-conditioning, and BDNF was measured.

RESULTS

Results indicated IA memory impairment in T. gondii-infected animals since lower step-through latency (STL) was observed than in control animals. We found significant (P = 0.01, P = 0.001) elevations in STL and a significant decrease (P = 0.001) in total time spent in the dark area following BRB administration in infected and Ket-treated rats, indicating improvement (increased STL) in consolidation and reconsolidation memory. Moreover, BDNF levels were reduced (P = 0.01) in the hippocampus and mPFC regions of both T. gondii- infected and Ket-induced groups, which remarkably enhanced after BRB treatment. Furthermore; we found that BRB administration notably increased the mPFC BDNF levels in mPFC (P < 0.01) and hippocampus (P = 0.001) in the Ket-treated and rats infected with T. gondii.

CONCLUSION

Taken together; BRB may be a valuable preclinical treatment for improving memory impairment through BDNF expression in PFC and hippocampus, therefore; BRB is suggested for memory disturbances induced by T. gondii infection.

Evaluation of Brain Targeting and Antipsychotic Activity of Nasally Administrated Ziprasidone Lipid-Polymer Hybrid Nanocarriers

The feasibility of using lipid-polymer hybrid (LPH) nanocarriers as a potential platform for the intranasal delivery of ziprasidone (ZP), a second-generation antipsychotic, was explored. Different ZP-loaded LPH composed of a PLGA core and cholesterol-lecithin lipid coat were prepared using a single step nano-precipitation self-assembly technique. Modulation of polymer, lipid and drug amounts, as well as stirring-speed-optimized LPH with a particle size of 97.56 ± 4.55 nm and a ZP entrapment efficiency (EE%) of 97.98 ± 1.22%. The brain deposition and pharmacokinetics studies proved the efficiency of LPH to traverse the blood-brain barrier (BBB) following intranasal delivery with a 3.9-fold increase in targeting efficiency compared to the intravenous (IV) ZP solution with a direct nose-to-brain transport percentage (DTP) of 74.68%. The ZP-LPH showed enhanced antipsychotic activity in terms of animals' hypermobility over an IV drug solution in schizophrenic rats. The obtained results showed that the fabricated LPH was able to improve ZP brain uptake and proved its antipsychotic efficiency.

Season, storage and extraction method impact on the phytochemical profile of Terminalia ivorensis

BACKGROUND

Terminalia ivorensis (TI) is used in West African ethnomedicine for the treatment of conditions including ulcers, malaria and wounds. Despite its widespread use, the phytochemical profile of TI remains largely undetermined. This research investigated the effects of extraction method, season, and storage conditions on the phytochemical composition of TI to contribute towards understanding the potential benefits.

METHODS

TI bark was collected in September 2014, September 2018 and February 2018 during the rainy or dry seasons in Eastern Region, Ghana. Samples were extracted sequentially with organic solvents (petroleum ether, chloroform, ethyl acetate and ethanol) or using water (traditional). Metabolites were identified by liquid chromatography-mass spectrometry/mass spectrometry and compared statistically by ANOVA.

RESULTS

A total of 82 different phytochemicals were identified across all samples. A greater yield of the major phytochemicals (44%, p < 0.05) was obtained by water as compared with organic extraction. There was also a higher concentration of metabolites present in cold (63%, p < 0.05) compared with hot water extraction. A significantly (p < 0.05) higher number of phytochemicals were identified from TI collected in the dry (85%) compared to the rainy season (69%). TI bark stored for four years retained 84% of the major phytochemicals.

CONCLUSION

This work provides important information on composition and how this is modified by growing conditions, storage and method of extraction informing progress on the development of TI as a prophylactic formulation or medicine.

Nano-hesperetin attenuates ketamine-induced schizophrenia-like symptoms in mice: participation of antioxidant parameters

RATIONALE

Antioxidant natural herb hesperetin (Hst) offers powerful medicinal properties. Despite having noticeable antioxidant properties, it has limited absorption, which is a major pharmacological obstacle.

OBJECTIVES

The goal of the current investigation was to determine if Hst and nano-Hst might protect mice against oxidative stress and schizophrenia (SCZ)-like behaviors brought on by ketamine (KET).

METHODS

Seven treatment groups (n=7) were created for the animals. For 10 days, they received distilled water or KET (10 mg/kg) intraperitoneally (i.p). From the 11th to the 40th day, they received daily oral administration of Hst and nano-Hst (10, 20 mg/kg) or vehicle. With the use of the forced swimming test (FST), open field test (OFT), and novel object recognition test (NORT), SCZ-like behaviors were evaluated. Malondialdehyde (MDA) and glutathione levels and antioxidant enzyme activities were assessed in the cerebral cortex.

RESULTS

Our findings displayed that behavioral disorders induced by KET would be improved by nano-Hst treated. MDA levels were much lower after treatment with nano-Hst, and brain antioxidant levels and activities were noticeably higher. The mice treated with nano-Hst had improved outcomes in the behavioral and biochemical tests when compared to the Hst group.

CONCLUSIONS

Our study's findings showed that nano-Hst had a stronger neuroprotective impact than Hst. In cerebral cortex tissues, nano-Hst treatment dramatically reduced KET-induced (SCZ)-like behavior and oxidative stress indicators. As a result, nano-Hst may have more therapeutic potential and may be effective in treating behavioral impairments and oxidative damage brought on by KET.

Pharmacological screening of silibinin for antischizophrenic activity along with its acute toxicity evaluation in experimental animals

Silibinin (SIL), a flavolignan extracted from the medicinal plant "silybum marianum (milk thistle)", has traditionally been used to treat liver disease. This phytochemical has displayed neuroprotective properties, its activity against schizophrenia is not elucidated. The present study was designed to evaluate the antipsychotic potential of silibinin and probe its toxic potential. The acute oral toxicity study was assessed as per OECD 425 guidelines. Animals were divided into two groups of female rats (n = 6): one group served as the normal control and the other group received a 2,000 mg/kg dose of SIL. We also evaluated the antipsychotic potential of SIL. To this end, animals were divided into six groups (n = 10) of mice for both the preventive and curative protocols. Group I (CMC 1 mL/kg) served as the normal control and received CMC 1 mL/kg; group II was the diseased group treated with ketamine (10 mg/kg) i.p; group III was the standard group treated with clozapine 1 mg/kg; groups IV, V, and VI served as the treatment groups, receiving SIL 50, 100, and 200 mg/kg, respectively, orally for both protocols. Improvement in positive symptoms of the disease was evaluated by stereotypy and hyperlocomotion, while negative symptoms (behavioral despair) were determined by a forced swim test and a tail suspension test in the mice models. The results suggested that the LD₅₀ of SIL was greater than 2,000 mg/kg. Moreover, SIL prevented and reversed ketamine-induced increase in stereotypy (p < 0.001) and behavioral despair in the forced swim and tail suspension tests (p < 0.001). Taken together, the findings suggest that silibinin is a safe drug with low toxicity which demonstrates significant antipsychotic activity against the positive and negative symptoms of schizophrenia.

Sarcosine (glycine transporter inhibitor) attenuates behavioural and biochemical changes induced by ketamine, in the rat model of schizophrenia

Schizophrenia is a neurological disorder that alters the behavior and affects the quality of life of a patient. It is characterized by hallucinations, disorganized behavior, cognitive dysfunction, hyperlocomotion, and loss of the reward system. Schizophrenia constitutes three symptoms' domains, viz. positive, negative and cognitive. Typical and atypical antipsychotics do not fully resolve all the symptoms' domains thus paving the way to the genesis of the glutamatergic hypothesis, i.e. N-methyl-D-aspartate (NMDA) receptor hypofunction in the pathophysiology of schizophrenia. Positive modulation of NMDA receptors by enhancing co-agonist, glycine effect is proposed to produce a therapeutic effect in schizophrenia. Hence, sarcosine (N-methyl glycine), natural amino acid, and a glycine transporter inhibitor (GlyT-1) which also acts on NMDA receptors were used in the present study. The present study unravels the role of sarcosine in the attenuation of ketamine-induced three symptom domains in a rat model through modulation of oxidative stress, mitochondrial dysfunction, and neuroinflammatory pathways. The animal model of schizophrenia was established by injecting ketamine intraperitoneal (ip) at a 30 mg/kg dose for 10 consecutive days, after which sarcosine (300, 600 mg/kg, ip) as a treatment was given for 7 days followed by behavioral, biochemical, molecular, and histopathological analysis. It was revealed that sarcosine reversed ketamine-induced behavioral impairments. Moreover, sarcosine ameliorated oxidative and nitrosative stress, mitochondrial dysfunction, and neuroinflammation and showed protective effects in histopathological examination by hematoxylin and eosin staining. Hence, conclusively, sarcosine was regarded to attenuate the behavioural symptoms of schizophrenia by alleviating oxidative stress, neuroinflammation, and mitochondrial dysfunction established by the ketamine.

Mechanisms underpinning Carpolobia lutea G. Don ethanol extract's neurorestorative and antipsychotic-like activities in an NMDA receptor antagonist model of schizophrenia

ETHNOPHARMACOLOGICAL RELEVANCE

Persistent ketamine insults to the central nervous system block NMDA receptors and disrupt putative neurotransmission, oxido-nitrosative, and inflammatory pathways, resulting in schizophrenia-like symptoms in animals. Previously, the ethnomedicinal benefits of Carpolobia lutea against insomnia, migraine headache, and insanity has been documented, but the mechanisms of action remain incomplete.

AIM OF THE STUDY

Presently, we explored the neuro-therapeutic role of Carpolobia lutea ethanol extract (C. lutea) in ketamine-induced schizophrenia-like symptoms in mice.

MATERIALS AND METHODS

Sixty-four male Swiss (22 ± 2 g) mice were randomly assigned into eight groups (n = 8/group) and exposed to a reversal ketamine model of schizophrenia. For 14 days, either distilled water (10 mL/kg; p.o.) or ketamine (20 mg/kg; i.p.) was administered, following possible reversal treatments with C. lutea (100, 200, 400, and 800 mg/kg; p.o.), haloperidol (1 mg/kg, p.o.), or clozapine (5 mg/kg; p.o.) beginning on days 8-14. During the experiment, a battery of behavioral characterizations defining schizophrenia-like symptoms were obtained using ANY-maze software, followed by neurochemical, oxido-inflammatory and histological assessments in the mice brains.

RESULTS

A 7-day reversal treatment with C. lutea reversed predictors of positive, negative and cognitive symptoms of schizophrenia. C. lutea also mitigated ketamine-induced neurochemical derangements as evidenced by modulations of dopamine, glutamate, norepinephrine and serotonin neurotransmission. Also, the increased acetylcholinesterase activity, malondialdehyde nitrite, interleukin-6 and tumor necrosis-factor-α concentrations were reversed by C. lutea accompanied with elevated levels of catalase, superoxide dismutase and reduced glutathione. Furthermore, C. lutea reversed ketamine-induced neuronal alterations in the prefrontal cortex, hippocampus and cerebellum sections of the brain.

CONCLUSION

These findings suggest that C. lutea reverses the cardinal symptoms of ketamine-induced schizophrenia in a dose-dependent fashion by modulating the oxido-inflammatory and neurotransmitter-related mechanisms.

Lipopolysaccharide Exacerbates Ketamine-Induced Psychotic-Like Behavior, Oxidative Stress, and Neuroinflammation in Mice: Ameliorative Effect of Diosmin

Schizophrenia, a neuropsychiatric disorder has been associated with aberrant neurotransmission affecting behaviors, social preference, and cognition. Limitations in understanding its pathogenesis via the dopamine hypothesis have engendered other hypotheses such as the glutamate hypothesis. That antagonism of the N-methyl-D-aspartate receptor (NMDAR) elicits schizophrenia-like behaviors indistinguishable from the disorder in animal and human models. There are growing concerns that redox imbalance and neuro-immuno dysfunction may play role in aggravating the symptomologies of this disorder. This 14-day treatment study was designed to investigate the effect of diosmin on lipopolysaccharide (LPS) plus ketamine (NMDAR antagonist). Mice were divided into 4 groups (n = 6). Group 1 was administered 5% DMSO (10 mL/kg, i.p) while group 2-4 received LPS (0.1 mg/kg, i.p) daily for 14 days. Diosmin (50 mg/kg, i.p) and risperidone (0.5 mg/kg, i.p) were given to groups 3 and 4 respectively. Groups 2-4 were given KET (20 mg/kg, i.p.) daily from days 8-14. Behavioral tests were done 30 min after the last dose, and oxidative stress and neuroinflammatory maker were assayed. LPS plus ketamine-induced hyperlocomotion, stereotypy, decreased social preference, and memory impairment. Furthermore, LPS plus-ketamine-induced oxidative stress (reduced GSH, CAT, SOD, and increased MDA and nitrite levels) and marked pro-inflammatory cytokines TNF-α and IL-6 suggesting neuroinflammation. However, diosmin attenuated behavioral deficits and improved memory. Additionally, diosmin potentiated antioxidant level via increased GSH, CAT, and SOD while reducing MDA and nitrite levels. Finally, diosmin reduced TNF-α and IL-6 suggesting anti-neuro-immuno activity. Conclusively, diosmin attenuated LPS plus ketamine-induced behavioral deficits, oxidative stress, neuroinflammation, and improved memory.

Cognition Enhancing Potential of Aqueous Leaf Extract of Amaranthus dubius in Mice

Amaranthus dubius is a vegetable consumed for its nutritional content in Kenya. In herbal medicine, A. dubius is utilized to relief fever, anemia and hemorrhage. Additionally, it is utilized to manage cognitive dysfunction and is considered to augment brain function, but there is no empirical evidence to support this claim. The contemporary study investigated cognitive enhancing potential of A. dubius in mice model of Alzheimer's disease (AD)-like dementia induced with ketamine. Cognitively damaged mice were treated with aqueous extract of A. dubius leaf upon which passive avoidance task (PAT) was used to assess the cognitive performance. At the end of passive avoidance test, brains of the mice were dissected to evaluate the possibility of the extract to inhibit hallmarks that propagate AD namely oxidative stress and acetylcholinesterase activity. Additionally, characterization of secondary metabolites was done using liquid chromatograph- mass spectrometry analysis. During PAT test, extract-treated mice showed significantly increased step-through latencies than AD mice, depicting ability of A. dubius to reverse ketamine-induced cognitive decline. Further, the extract remarkably lowered malondialdehyde levels to normal levels and effectively inhibited acetylcholinesterase enzyme. The study showed that A. dubius extract is endowed with phytoconstituents that possess anti-oxidant and anticholinesterase activities. Thus, this study confirmed promising therapeutic effects of 200, 300 and 400 mg/kg bw of A. dubius extract with potential to alleviate cognitive disarray observed in AD.

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.

Taurine, an essential β-amino acid insulates against ketamine-induced experimental psychosis by enhancement of cholinergic neurotransmission, inhibition of oxidative/nitrergic imbalances, and suppression of COX-2/iNOS immunoreactions in mice

Cholinergic, oxidative, nitrergic alterations, and neuroinflammation are some key neuropathological features common in schizophrenia disease. They involve complex biological processes that alter normal behavior. The present treatments used in the management of the disorder remain ineffective together with some serious side effects as one of their setbacks. Taurine is a naturally occurring essential β-amino acid reported to elicit antipsychotic property in first episode psychosis in clinical setting, thus require preclinical investigation. Hence, we set out to investigate the effects of taurine in the prevention and reversal of ketamine-induced psychotic-like behaviors and the associated putative neurobiological mechanisms underlying its effects. Adult male Swiss mice were sheared into three separate cohorts of experiments (n = 7): drug alone, preventive and reversal studies. Treatments consisted of saline (10 mL/kg/p.o./day), taurine (50 and 100 mg/kg/p.o./day) and risperidone (0.5 mg/kg/p.o./day) with concomitant ketamine (20 mg/kg/i.p./day) injections between days 8-14, or 14 days entirely. Behavioral hyperactivity, despair, cognitive impairment, and catalepsy were measured. Brain oxidative/nitrergic imbalance, immunoreactivity (COX-2 and iNOS), and cholinergic markers were determined in the striatum, prefrontal-cortex, and hippocampus. Taurine abates ketamine-mediated psychotic-like episodes without cataleptogenic potential. Taurine attenuated ketamine-induced decrease in glutathione, superoxide-dismutase and catalase levels in the striatum, prefrontal-cortex and hippocampus. Also, taurine prevented and reversed ketamine-mediated elevation of malondialdehyde, nitrite contents, acetylcholinesterase activity, and suppressed COX-2 and iNOS expressions in a brain-region dependent manner. Conclusively, taurine insulates against ketamine-mediated psychotic phenotype by normalizing brain central cholinergic neurotransmissions, oxidative, nitrergic and suppression of immunoreactive proteins in mice brains.

Pretreatment with Carpolobia lutea ethanol extract prevents schizophrenia-like behavior in mice models of psychosis

ETHNOPHARMACOLOGICAL RELEVANCE

Carpolobia lutea decoction is widely used as a phytotherapeutic against central nervous system-related disorders including insomnia, migraine headache, and mental illness in West and Central Tropical Africa.

AIM

This study was designed to investigate the antipsychotic activity of Carpolobia lutea (EECL) in mice models of psychosis.

METHODS

Male Swiss mice (n = 5/group) were given EECL (100, 200, 400, and 800 mg/kg), haloperidol (1 mg/kg), clozapine (5 mg/kg) and vehicle (10 mL/kg) orally before amphetamine (5 mg/kg)-induced hyperlocomotion and stereotypy, apomorphine (2 mg/kg)-induced stereotypy, or ketamine (10, 30, and 100 mg/kg)-induced hyperlocomotion, enhancement of immobility and cognitive impairment.

RESULTS

EECL (200, 400, and 800 mg/kg) prevented amphetamine- and apomorphine-induced stereotypies, as well as reduced hyperlocomotion induced by amphetamine and ketamine, all of which are predictors of positive symptoms. Regardless of the dose administered, EECL prevented the index of negative symptoms induced by ketamine. Furthermore, higher doses of EECL (400 and 800 mg/kg) also prevented ketamine-induced cognitive impairment, a behavioral phenotype of cognitive symptoms.

CONCLUSION

Pretreatment with EECL demonstrated antipsychotic activity in mice, preventing amphetamine-, apomorphine-, and ketamine-induced schizophrenia-like symptoms, with 800 mg/kg being the most effective dose.

Utilization of Polymeric Micelles as a Lucrative Platform for Efficient Brain Deposition of Olanzapine as an Antischizophrenic Drug via Intranasal Delivery

Schizophrenia is a mental disorder characterized by alterations in cognition, behavior and emotions. Oral olanzapine (OZ) administration is extensively metabolized (~up to 40% of the administrated dose). In addition, OZ is a P-glycoproteins substrate that impairs the blood–brain barrier (BBB) permeability. To direct OZ to the brain and to minimize its systemic side effects, the nasal pathway is recommended. OZ-loaded polymeric micelles nano-carriers were developed using suitable biodegradable excipients. The developed micelles were physicochemically investigated to assess their appropriateness for intranasal delivery and the potential of these carriers for OZ brain targeting. The selected formula will be examined in vivo for improving the anti-schizophrenic effects on a schizophrenia rat model. The binary mixture of P123/P407 has a low CMC (0.001326% w/v), which helps in maintaining the formed micelles’ stability upon dilution. The combination effect of P123, P407 and TPGS led to a decrease in micelle size, ranging between 37.5–47.55 nm and an increase in the EE% (ranging between 68.22–86.84%). The selected OZ–PM shows great stability expressed by a suitable negative charge zeta potential value (−15.11 ± 1.35 mV) and scattered non-aggregated spherical particles with a particle size range of 30–40 nm. OZ–PM maintains sustained drug release at the application site with no nasal cytotoxicity. In vivo administration of the selected OZ–PM formula reveals improved CNS targeting and anti-schizophrenia-related deficits after OZ nasal administration. Therefore, OZ–PM provided safe direct nose-to-brain transport of OZ after nasal administration with an efficient anti-schizophrenic effect.

Neuroprotective effects of curcumin-loaded nanophytosome on ketamine-induced schizophrenia-like behaviors and oxidative damage in male mice

Curcumin as an antioxidant natural herb has shown numerous pharmacological effects. However, the poor bioavailability of curcumin is a significant pharmacological barrier for its antioxidant activities. The present study was conducted to develop curcumin-loaded nanophytosome (CNP) and explore their therapeutic potential in a ketamine (KET)-induced schizophrenia (SCZ) model. The mice in our experiment were treated orally with curcumin and CNP (20 mg/kg) for 30 consecutive days. In addition, the animals received intraperitoneal injection of KET (30 mg/kg/day) from the 16th to the 30th day. SCZ-like behaviors were evaluated employing forced swimming test (FST), open field test (OFT), and novel object recognition test (NORT), and oxidative stress markers in the brain were estimated. Our results revealed that CNP has a greater neuroprotective effect compared to free curcumin. CNP pretreatment significantly ameliorated KET-induced brain injury evidenced by a marked reduction in the depressive and anxiety-like behaviors, memory deficits, and oxidative stress markers in cortical and subcortical tissues. Therefore, CNP, as a suitable drug delivery system, may improve curcumin bioavailability and confer stronger neuroprotective effects against KET-induced behavioral deficits and oxidative damages.

Long Acting Polycaprolactone Based Parenteral Formulation of Aripiprazole Targeting Behavioural and Biochemical Deficit in Schizophrenia

Schizophrenia is a neurodevelopmental disorder which is expressed in the form of disturbed behaviour and abnormal mental functions. Patient's non-adherence to the medicine is the main cause of failure of drug therapy and increases incidence of relapses. Thus, for successful management of disease long acting parenteral formulations were developed. Aripiprazole was encapsulated in biocompatible polycaprolactone microsphere by o/w emulsion solvent-evaporation method in order to achieve sustained release of the drug for several weeks after single subcutaneous administration. They were optimised on the basis of various parameters such as physical appearance, particle size (49.4 μm-387.1 μm), encapsulation efficiency (70%-95%), percentage yield (33%-75%) and drug loading (25.9%-47.5%). The surface topography and sphericity of the microspheres was determined by scanning electron microscopy which revealed that the microspheres formed were spherical and non-porous in nature. The in vitro releases from the selected formulations were found to be 87% and 95% respectively after 45 days of dissolution. In vivo efficacy of optimised formulation showed significantly (p < 0.05) amelioration of various positive, negative and cognitive symptoms associated with schizophrenia and oxidative stress markers in ketamine-induced schizophrenia model in rats for 30 days.

Regulation of Reactive Oxygen Species-Mediated Damage in the Pathogenesis of Schizophrenia

The biochemical integrity of the brain is paramount to the function of the central nervous system, and oxidative stress is a key contributor to cerebral biochemical impairment. Oxidative stress, which occurs when an imbalance arises between the production of reactive oxygen species (ROS) and the efficacy of the antioxidant defense mechanism, is believed to play a role in the pathophysiology of various brain disorders. One such disorder, schizophrenia, not only causes lifelong disability but also induces severe emotional distress; however, because of its onset in early adolescence or adulthood and its progressive development, consuming natural antioxidant products may help regulate the pathogenesis of schizophrenia. Therefore, elucidating the functions of ROS and dietary antioxidants in the pathogenesis of schizophrenia could help formulate improved therapeutic strategies for its prevention and treatment. This review focuses specifically on the roles of ROS and oxidative damage in the pathophysiology of schizophrenia, as well as the effects of nutrition, antipsychotic use, cognitive therapies, and quality of life on patients with schizophrenia. By improving our understanding of the effects of various nutrients on schizophrenia, it may become possible to develop nutritional strategies and supplements to treat the disorder, alleviate its symptoms, and facilitate long-term recovery.

The Terminalia laxiflora modulates the neurotoxicity induced by fipronil in male albino rats

The extensive use of fipronil (FPN) may trigger hazards to more than insects. The present investigation was carried out to evaluate the abrogating role of Terminalia laxiflora (TL) methanol extract (TLE) against the neurotoxic effects provoked by FPN. Fourty male albino rats were assigned into four equal groups. The first group served as control, the second one was orally administered FPN (10.5 mg/kg BW), the third group was given combination of FPN and TLE) (100 mg/kg BW), and the fourth one was orally given TLE. Our findings highlighted the efficacy of TLE as a neuroprotectant through a significant reduction in malondialdehyde (MDA) content by 25.8%, elevations of the reduced glutathione (GSH) level, catalase (CAT,) and superoxide dismutase (SOD) activities by 30.9, 41.2, and 48.2% respectively. Consequently, the relative mRNA levels of both Bax and caspase-3 were down-regulated by 40.54% and caspase-3 by 30.35% compared with the control group. Moreover, restoration of the pathological tissue injuries were detected. In conclusion, TLE proved to be a potent neuroprotective agent against the FPN-induced toxicity.

Probable mechanisms involved in the antipsychotic-like activity of morin in mice

Evidence derived from preliminary studies suggests that morin, a neuroactive flavonoid with proven antioxidant and antiinflammatory properties possess antipsychotic-like activity. The present study was designed to evaluate the probable mechanisms involve in the antipsychotic-like activity of morin in ketamine model of schizophrenia. The effects of morin, haloperidol and risperidone on neurobehavioral and anti-schizophrenia-like effects were evaluated in mice (n = 7) following intraperitoneal (i.p.) administration of morin (25-100 mg/kg), haloperidol (1 mg/kg) and risperidone (0.5 mg/kg) alone or in combination with ketamine (20 mg/kg, i.p.) for 10 days. Neurobehavioral and schizophrenia-like activities consisting of open-field (positive symptoms), Y-maze, novel-object recognition (cognitive symptoms), social interaction (negative symptoms) tests were assessed. Also, wood-block catalepsy and rota-rod tests were employed to evaluate extrapyramidal side effects of morin. Thereafter, brain levels of biomarkers of oxidative, nitrergic and acetylcholinesterase alterations as well as histomorphological changes in the striatum and prefrontal-cortex were determined. Administration of morin and risperidone alone but not haloperidol significantly (p > 0.05) prevented ketamine-induced hyperlocomotion, social withdrawal and cognitive impairments relative to controls, and were devoid of extrapyramidal side effects. Morin alone or in combination with ketamine significantly increased glutathione concentration, superoxide dismutase and catalase activities compared with saline- or ketamine-treated mice. Moreover, morin alone or in combination with ketamine also significantly decreased malondialdehyde, nitrite and acetylcholinesterase alterations in mice brains. Furthermore, morin prevented ketamine-induced brain neuronal alterations in the striatum and prefrontal-cortex. Together, our findings suggest that morin may demonstrate antipsychotic-like therapeutic effect via modulation of oxidative/nitrergic, cholinergic actions and neuroprotection.

Involvement of GABAergic, BDNF and Nox-2 mechanisms in the prevention and reversal of ketamine-induced schizophrenia-like behavior by morin in mice

GABAergic (Gamma-aminobutyric acid) and neurotrophic derangements have important implication in schizophrenia, a neuropsychiatric disease. Previous studies have shown that nicotinamide adenine dinucleotide phosphate oxidase (NADPH-oxidase) alters GABAergic and neurotrophic activities via inflammatory and oxidative pathways. Thus, it has been proposed that agents with anti-oxidant and anti-inflammatory properties might be beneficial for the treatment of the disease. Morin is neuroactive bioflavonoid compound, which has been reported to demonstrate antipsychotic and anti-oxidant/anti-inflammatory activities. In this study, we further evaluated its effects on the brain markers of GABAergic, neurotrophic and oxidative alterations in the preventive and reversal of schizophrenia-like behavior induced by ketamine (KET). In the prevention protocol, adult mice were treated intraperitoneally with morin (100 mg/kg/day), haloperidol (1 mg/kg/day), risperidone (0.5 mg/kg/day), or saline (10 mL/kg/day) for 14 consecutive days. In addition, the animals were administered KET (20 mg/kg/day) from the 8th to the 14th day. In the reversal protocol, the animals received KET or saline for 14 days. From 8th to 14th days mice were additionally treated with morin, haloperidol, risperidone or saline. Schizophrenic-like behaviors consisting of positive (stereotypy test), negative (behavioral despair in forced swim test) and cognitive (novel-object recognition test) symptoms were evaluated. Afterwards, brain levels of biomarkers of GABAergic (Glutamic acid decarboxylase-67, GAD₆₇), neurotrophic (Brain-derived neurotrophic factor, BDNF) and oxidative [NADPH-oxidase, superoxide dismutase, (SOD) and catalase (CAT)] alterations were determined in the striatum, prefrontal cortex (PFC) and hippocampus, respectively. Morin significantly (p < 0.05) prevented and reversed KET-induced increased stereotypy, behavioral despair and deficit in cognitive functions when compared with KET-treated mice respectively. Also, morin and risperidone but not haloperidol, significantly (p < 0.05) prevented and reversed the decreases in expressions of GAD₆₇ and BDNF immunoreactivity in the striatum, PFC and hippocampus caused by KET. Moreover, morin and risperidone significantly (p < 0.05) decreased regional brain expressions of NADPH-oxidase immunopositive cells and increased endogenous anti-oxidant enzymes (SOD and CAT) in the striatum, PFC and hippocampus relative to KET controls respectively. Taken together, these findings further suggest that the antipsychotic-like activity of morin may be mediated via mechanisms related to enhancement of GABAergic neurotransmission and neurotrophic factor, and suppression of NADPH-oxidase induced oxidative damage in mice.

Protective effects of tetrahydropalmatine against ketamine-induced learning and memory injury via antioxidative, anti-inflammatory and anti-apoptotic mechanisms in mice

Tetrahydropalmatine exerts numerous pharmacological activities, including analgesic and narcotic effects; anti-arrhythmic, blood pressure lowering and cardioprotective effects; protective effects against cerebral ischemia-reperfusion injury; inhibition of platelet aggregation; prevention of ulcerative diseases and inhibition of gastric acid secretion; antitumor effects; and beneficial effects on the withdrawal symptoms associated with drug addiction. The present study aimed to investigate the protective effects of tetrahydropalmatine against ketamine‑induced learning and memory impairment in mice. The Morris water maze test and open field test were used to analyzed learning and memory impairment in mice. ELISA kits and western blotting were used to analyze oxidative stress, inflammation factors, caspease‑3 and caspase‑9, iNOS, glial fibrillary acidic protein (GFAP), glial cell‑derived neurotrophic factor (GDNF), cytochrome c and phospholipase C (PLC)‑γ1 protein expression. The results demonstrated that tetrahydropalmatine treatment significantly decreased escape latency in the learning phase and increased the number of platform site crossings in ketamine‑induced mice. In addition, tetrahydropalmatine significantly inhibited oxidative stress, inflammation and acetylcholinesterase activity, and decreased acetylcholine levels in ketamine‑induced mice. Tetrahydropalmatine also suppressed iNOS protein expression, weakened caspase‑3 and caspase‑9 activation, inhibited nuclear factor‑κB, glial fibrillary acidic protein, cytochrome c and phospholipase C‑γ1 protein expression, and induced glial cell‑derived neurotrophic factor protein expression in ketamine‑induced mice. Taken together, these results indicated that tetrahydropalmatine may protect against ketamine‑induced learning and memory impairment in mice via antioxidative, anti‑inflammatory and anti‑apoptotic mechanisms. The present study provided an experimental basis for the clinical application of tetrahydropalmatine to reduce the severe side effects associated with ketamine therapy in future studies.