Nigella sativa Oil Enhances the Spatial Working Memory Performance of Rats on a Radial Arm Maze

Concept of dementia (Nisy ā n) in Unani system of medicine and scientific validation of an important Unani pharmacopoeial preparation 'Majoon Vaj' for its management: a review

OBJECTIVES

This review focused on the concept of dementia in the Unani system of medicine and comprehensive, updated information on Majoon Vaj about the phytochemistry, nootropic, CNS activities and provide insights into potential opportunities for future research.

METHODS

The classical literature on Majoon Vaj for its anti-dementic properties, and therapeutic uses were gathered from nearly thirteen classical Unani books including Unani Pharmacopoeia. The information of pharmacognosy, phytochemical and pharmacological activities of Majoon Vaj and its ingredient was collected by browsing the Internet (PubMed, ScienceDirect, Wiley online library, Google Scholar, ResearchGate). The relevant primary sources were probed, analysed, and included in this review. The keywords used to browse were Majoon Vaj, Dementia, Nootropic, Acorus calamus, Piper nigram, Zingiber officinalis, Nigella sativa, Carum carvi, Plumbago zeylanica, and β-asarone. Relevant Sources were gathered up to July 2021, and the chemical structures were drawn using ACD/ChemSketch software. The species name and synonyms were checked with WFO (2021): World Flora online (http://www.worldfloraonline.org) an updated version of 'The Plant List.'

RESULTS

Majoon Vaj contains an excess of bioactive compounds e.g., alkaloids, phenols, flavonoids, tannins, diterpenes, coumarins, carbohydrates, and fixed oils and its ingredients possess broad pharmacological properties, including cognitive-enhancing, neuroprotective, anti-inflammatory, antioxidant and antimicrobial properties.

CONCLUSIONS

The literature of Unani medicine is quite rich in discussing the pathophysiological basis of memory disorders. It argues that memory, retention, and retrieval are regulated by a complex process involving various faculties. Majoon Vaj seems to have great potential for therapeutic applications in the treatment of dementia and thus encourage more preclinical and clinical trials in this field.

Effect of hydro-alcoholic extract of Nigella sativa on cisplatin-induced memory impairment and brain oxidative stress status in male rats

Objective

Studies have shown the complications of chemotherapy on learning and memory. Empirical evidence suggests that Nigella sativa (NS) has neuroprotective activities. Therefore, the aim of our study was to investigate the effects of NS on cisplatin-induced memory impairment.

Materials and Methods

This study was conducted on 40 male rats grouped as: control (saline: 2 ml/kg, intraperitoneally (IP), once weekly/2 weeks), cisplatin (Cis, 2 mg/kg, IP, once weekly/2 weeks), NS (200 mg/kg, IP, once weekly/2 weeks), Cis +NS 200 (2 mg/kg Cis + 200 mg/kg NS, IP, once weekly/2 weeks), and Cis +NS 400 (2 mg/kg Cis + 400 mg/kg NS, IP, once weekly/2 weeks). Morris water maze (MWM) test was used to assess spatial learning and memory. In addition, superoxide dismutase (SOD) activity, and thiol and malondialdehyde (MDA) levels were evaluated in the brain.

Results

Cis significantly enhanced the traveled distance and time spent in the target quadrant in the MWM test. Additionally, MDA levels increased in the Cis group, while thiol and SOD decreased in this group. As a result of treatment with NS, behavioral results were reversed in the groups receiving NS compared to the Cis group. Also, NS reduced MDA level but improved SOD and thiol levels in brain tissue samples.

Conclusion

NS could improve memory impairment and oxidative stress in animals receiving Cis. Therefore, NS could be used as a potential food supplement to prevent neurotoxicity in patients undergoing chemotherapy.

Survival, growth, behavior, hematology and serum biochemistry of mice under different concentrations of orally administered amorphous silica nanoparticle

Silica nanoparticles (SiNPs) are used extensively in consumer products and biomedical research basically due to ease of production and low cost. However, insufficient literature is reported regarding the toxicity and biocompatibility of SiNPs. The present study aimed to investigate the potential role of amorphous SiNPs on survival, growth, behavioral alterations, hematology and serum biochemistry of mice at four concentrations (control, 50, 100 and 150 mg/kg/day) of an oral supplementation for a period of 3 months. Signs of toxicity (lethargy, nausea, coma, tremors, vomiting and diarrhea, etc.) were noted at 9:00 am and 9:00 pm (twice a day) and the body weight of each of these mice was measured every week. The data were subjected to mean, standard deviation (S.D). Moreover, One-Way Analysis of Variance (ANOVA) and Dunnett's test were applied for analysis of statistical significance between groups by using SPSS software, version 20. All the mice survived with minor alterations in behavior and no significant weight changes were observed during the stipulated time period. Complete blood count (CBC) analysis indicated non-significant (P ≥ 0.05) systemic dysfunctions of organ systems. However, there was elevation in the level of AST and ALT in the analysis of serum biochemistry, while the values of all other examined parameters were not-significant (P ≥ 0.05). The study concluded that orally administered large silica nanoparticles up to the dose level of 150 mg/kg/day are nontoxic for the in vivo use in mice.

From kitchen to clinic: Pharmacotherapeutic potential of common spices in Indian cooking in age-related neurological disorders

Aging is described as an advanced time-related collection of changes that may negatively affect with the risk of several diseases or death. Aging is a main factor of several age-related neurological disorders, including neurodegenerative diseases (Alzheimer’s disease, Parkinson’s disease, and dementia), stroke, neuroinflammation, neurotoxicity, brain tumors, oxidative stress, and reactive oxygen species (ROS). Currently available medications for age-related neurological disorders may lead to several side effects, such as headache, diarrhea, nausea, gastrointestinal (GI) diseases, dyskinesia, and hallucinosis. These days, studies on plant efficacy in traditional medicine are being conducted because herbal medicine is affordable, safe, and culturally acceptable and easily accessible. The Indian traditional medicine system called Ayurveda uses several herbs and medicinal plants to treat various disorders including neurological disorders. This review aims to summarize the data on the neuroprotective potential of the following common Indian spices widely used in Ayurveda: cumin (Cuminum cyminum (L.), Apiaceae), black cumin (Nigella sativa (L.), Ranunculaceae), black pepper (Piper nigrum (L.), Piperaceae), curry leaf tree (Murraya koenigii (L.), Spreng Rutaceae), fenugreek (Trigonella foenum-graecum (L.), Fabaceae), fennel (Foeniculum vulgare Mill, Apiaceae), cardamom (Elettaria cardamomum (L.) Maton, Zingiberaceae), cloves (Syzygium aromaticum (L.) Merr. & L.M.Perry, Myrtaceae), and coriander (Coriandrum sativum (L.), Apiaceae) in age-related neurological disorders.

Effects of Moringa oleifera on working memory: an experimental study with memory-impaired Wistar rats tested in radial arm maze

OBJECTIVE

Memory impairment is a serious problem that has a significant negative impact on survival and quality of life. When used for a long time, drugs used to treat memory loss become less effective and have more side effects, making therapy more difficult. Different medicinal plants are now being highlighted because of their valuable applications and low risk of adverse effects. Moringa oleifera is one of these plants that has gained much attention due to its diverse biological functions. The study aimed to determine the effects of Moringa oleifera on working memory in memory-impaired Wistar rats.

RESULTS

For this experimental study, 30 male Wistar rats having 150-250 g bodyweight were divided equally into three groups: Group-I/normal memory group (treated with oral normal saline 5 ml/kg body weight), Group-II/memory-impaired group (induced by intraperitoneal ketamine 15 mg/kg body weight), and Group-III/experimental group (treated with oral Moringa oleifera 200 mg/kg bodyweight and intraperitoneal ketamine 15 mg/kg body weight). The experimental group showed significantly fewer working memory errors than the memory-impaired group. The experimental group also provides the lowest variability of WMEs among groups. Thus, the study concludes that M. oleifera can prevent ketamine-induced memory impairment in Wistar rats.

Investigating binding mechanism of thymoquinone to human transferrin, targeting Alzheimer's disease therapy

Iron deposition in the central nervous system (CNS) is one of the causes of neurodegenerative diseases. Human transferrin (hTf) acts as an iron carrier present in the blood plasma, preventing it from contributing to redox reactions. Plant compounds and their derivatives are frequently being used in preventing or delaying Alzheimer's disease (AD). Thymoquinone (TQ), a natural product has gained popularity because of its broad therapeutic applications. TQ is one of the significant phytoconstituent of Nigella sativa. The binding of TQ to hTf was determined by spectroscopic methods and isothermal titration calorimetry. We have observed that TQ strongly binds to hTf with a binding constant (K) of 0.22 × 10⁶ M^-1 and forming a stable complex. In addition, isothermal titration calorimetry revealed the spontaneous binding of TQ with hTf. Molecular docking analysis showed key residues of the hTf that were involved in the binding to TQ. We further performed a 250 ns molecular dynamics simulation which deciphered the dynamics and stability of the hTf-TQ complex. Structure analysis suggested that the binding of TQ doesn't cause any significant alterations in the hTf structure during the course of simulation and a stable complex is formed. Altogether, we have elucidated the mechanism of binding of TQ with hTf, which can be further implicated in the development of a novel strategy for AD therapy.

Thymoquinone: Review of Its Potential in the Treatment of Neurological Diseases

Thymoquinone (TQ) possesses anticonvulsant, antianxiety, antidepressant, and antipsychotic properties. It could be utilized to treat drug misuse or dependence, and those with memory and cognitive impairment. TQ protects brain cells from oxidative stress, which is especially pronounced in memory-related regions. TQ exhibits antineurotoxin characteristics, implying its role in preventing neurodegenerative disorders such as Alzheimer’s disease and Parkinson’s disease. TQ’s antioxidant and anti-inflammatory properties protect brain cells from damage and inflammation. Glutamate can trigger cell death by causing mitochondrial malfunction and the formation of reactive oxygen species (ROS). Reduction in ROS production can explain TQ effects in neuroinflammation. TQ can help prevent glutamate-induced apoptosis by suppressing mitochondrial malfunction. Several studies have demonstrated TQ’s role in inhibiting Toll-like receptors (TLRs) and some inflammatory mediators, leading to reduced inflammation and neurotoxicity. Several studies did not show any signs of dopaminergic neuron loss after TQ treatment in various animals. TQ has been shown in clinical studies to block acetylcholinesterase (AChE) activity, which increases acetylcholine (ACh). As a result, fresh memories are programmed to preserve the effects. Treatment with TQ has been linked to better outcomes and decreased side effects than other drugs.

Chronic Administration of Thymoquinone Enhances Adult Hippocampal Neurogenesis and Improves Memory in Rats Via Regulating the BDNF Signaling Pathway

Thymoquinone is a pharmacologically active component of Nigella sativa Linn. seeds. Despite the diverse neuropharmacological attributes of TQ, limited reports related to adult neurogenesis and memory research are available. In this study, we investigated the effects of TQ on the proliferation and neural differentiation of cultured neural stem/progenitor cells (NSCs/NPCs). We also investigated the effect of TQ chronic administration on neurogenesis and memory in adult rats. Under proliferation conditions, TQ (0.05-0.3 μM) significantly increased NSCs/NPCs viability, neurosphere diameter, and cell count. TQ treatment under differentiation conditions increased the proportion of cells positive for Tuj1 (a neuronal marker). Furthermore, chronic oral administration of TQ (25 mg/kg/day for 12 weeks) to adult rats increased the number of bromodeoxyuridine (BrdU)-immunopositive cells double-stained with a mature neuronal marker, neuronal nuclei (NeuN), and a proliferation marker, doublecortin (Dcx), in the dentate gyrus of the hippocampus. TQ-administered rats showed a profound beneficial effect on avoidance-related learning ability, associated with an increase in the hippocampal mRNA and protein levels of brain-derived neurotrophic factor (BDNF), as measured by both real-time PCR and ELISA. Western blot analysis revealed that TQ stimulates the phosphorylation of cAMP-response element-binding protein (CREB), the upstream signaling molecule in the BDNF pathway. Furthermore, chronic administration of TQ decreased lipid peroxide and reactive oxygen species levels in the hippocampus. Taken together, our results suggest that TQ plays a role in memory improvement in adult rats and that the CREB/BDNF signaling pathways are involved in mediating the actions of TQ in hippocampal neurogenesis.

The effect of crocin on memory, hippocampal acetylcholine level, and apoptosis in a rat model of cerebral ischemia

Although the memory- improving effect of crocin has been suggested by previous evidences, the association between this effect and hippocampal acetylcholine (Ach) level and apoptosis is not well investigated. This study aimed to determine the protective effects of crocin on memory, hippocampal Ach level, and apoptosis in a rat model of cerebral ischemia. Male Wistar rats were divided into sham group received saline, and other 3 groups underwent 4-vessel occlusion brain ischemia (4VOI), received oral administration of either saline or crocin in doses of 30 mg/day and 60 mg/day for 7 days. Outcomes were memory, determined by radial eight-arm maze (RAM) task and Morris water maze (MWM) test, Ach release in the dorsal hippocampus (evaluated by microdialysis-HPLC) and apoptosis (investigated by TUNEL assay). 4VOI impaired memory reduced dorsal hippocampus Ach level, and induced apoptosis. Crocin, significantly improved the memory (F = 343.20; P < 0.001 for RAM error choices and F = 182.5; P < 0.0001 for MWM), increased Ach level (F = 115.1; P < 0.001) and prevented hippocampal neuronal apoptosis (W = 183.50; P < 0.001) as compared statistically by ANOVA test. Crocin can be suggested as a promising therapy for ischemic cerebrovascular accidents by its memory preserving, Ach-increasing, and neuroprotective effects.

Structural Characterization, Antimicrobial Activity, and In Vitro Cytotoxicity Effect of Black Seed Oil

This study was aimed to investigate the structure of bioactive components of black seed oil (BSO) and their antimicrobial and cytotoxic effects. Initially, the structural examination was conducted using various spectroscopic techniques, such as FTIR, TLC, and UV-visible spectroscopy, which are important in determining substituents, functional groups, and the presence of conjugated double bonds in BSO. From the FTIR spectra, a variety of sharp, strong, and weak peaks were specified relating to the main components of thymoquinone (TQ), dithymoquinone, thymohydroquinone, and thymol in BSO. The results of UV-visible spectroscopy confirmed the presence of thymoquinone as a major compound, and conjugated double bonds were also found. In addition, qualitative TLC analysis was used to identify thymoquinone from the methanol-extracted layer in BSO, by calculating the retention factor (R f) value. Furthermore, antimicrobial activity of BSO was studied against various types of bacteria. Strong bacterial inhibitory effects were observed, especially against Bacillus subtilis, with an average inhibition zone of 15.74 mm. Moreover, through the use of the MTT assay in vitro, it was shown that BSO does not exhibit any cytotoxicity towards human peripheral blood mononuclear cells (PBMCs). It was also found from the structural characterization of BSO that the existence of TQ is responsible for potential antibacterial activity without any cytotoxic effects. The main observation of this work is that BSO has antimicrobial activity even against methicillin-resistant Staphylococcus aureus (MRSA).

An evaluation of the efficacy of ethanolic extract of Nigella sativa L. (Kalonji) on the clinical parameters of moderate‑to‑severe gingivitis: A split‑mouth clinical study

Introduction

Gingivitis is a relatively innocuous and reversible inflammation of gingiva. If left untreated, it might progress involving the deeper supporting periodontal tissues of the tooth with consequent mobility and tooth loss. Compelling literature has suggested the role of local antibacterial and anti‑inflammatory agents as an adjunct to scaling and root planing (gold standard) for treating periodontal diseases. Various herbs such as Nimba (Azadirachta indica A. Juss), Babbula (Vachellia nilotica (L.) P.J.H. Hurter & Mabb.) and turmeric (Curcuma longa L.) have been used for gingivitis since ancient times. Nigella sativa L. (Kalonji) is one such herb known for its remarkable anti‑inflammatory, antioxidant and antimicrobial properties and thus has been utilized in the present study.

Aim

The aim of the study was to explore the clinical efficacy of different ethanolic solutions of N. sativa in moderate‑to‑severe gingivitis patients.

Materials and Methods

It is a split‑mouth clinical study with 24 patients of moderate‑to‑severe gingivitis from the age group of 25-45 years. Recruited individuals were divided in to group I₁, group II₁ and group III₁ (scaling and root planning i.e., control) and group I₂, group II₂ and group III₂ (experimental). Three doses of solution 1 (1:3), solution 2 (1:1) and solution 3 (3:1) were administered to the experimental groups for 3 consecutive days. The clinical parameters, i.e., gingival index (GI) and plaque index (PI) were recorded at baseline, 14 days and 28 days in all the individuals. ANOVA test was used in the study for statistical analysis.

Results

Intergroup comparison in terms of GI showed statistically significant difference at 14^th and 28^th day from baseline between I_{1 &}I_2, at only 28^th day between II₁ & II₂ and insignificant difference between III₁ & III₂ at all time intervals from baseline. On intragroup comparison, statistically significant reduction in GI in all groups from baseline till 28 days was found, but among experimental groups best result was seen in group III₂ (P < 0.001; F value 153.75). As far as PI is concerned, intergroup comparison between different groups displayed statistically significant difference from baseline to 14^th and 28^th day between all groups i.e I₁& I₂, II₁& II₂ and III₁& III₂. On intragroup comparison, statistically significant reduction in PI in all control groups i.e I_1, II₁ & III₁ was found, but among experimental groups only group III₂ provided statistically significant reduction (P < 0.001, F value 30.40).

Conclusion

The results of this study indicate that, the ethanolic extract of N. sativa is effective in the treatment of moderate to severe gingivitis.

Neuroprotective efficacy of thymoquinone against amyloid beta-induced neurotoxicity in human induced pluripotent stem cell-derived cholinergic neurons

The natural antioxidant Thymoquinone (TQ) is the most abundant ingredient in the curative plant Nigella sativa seed's oil. An extensive number of studies have revealed that TQ is the most active and most responsible component for the plant's pharmacological properties. It has been documented in several studies that TQ has a wide range of protective activities and many neuropharmacological attributes. Amyloid beta (Aβ) is the major role player peptide in the progression of Alzheimer's disease (AD). Our current study has been implemented to explore the protective possibilities of TQ on Aβ_1–42 -induced neurotoxicity. To test TQ's effect we used cultured human induced pluripotent stem cell (hiPSC)-derived cholinergic neurons. The obtained results showed that Aβ_1–42 caused cell death and apoptosis, which was efficiently attenuated by the co-treatment of TQ. Moreover, TQ restored the decrease in the intracellular antioxidant enzyme glutathione levels and inhibited the generation of reactive oxygen species induced by Aβ_1–42. Furthermore, using the fluorescent dye FM1–43 we demonstrated that TQ was able to reduce synaptic toxicity caused by Aβ_1–42. Thus, the findings of our study suggest that TQ holds a neuroprotective potential and could be a promising therapeutic agent to reduce the risk of developing AD and other disorders of the central nervous system.

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TQ protected hiPSC-derived cholinergic neurons against Aβ_1–42 induced apoptosis.

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TQ restored reduced Glutathione level in hiPSC-derived cholinergic neurons.

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TQ protected hiPSC-derived cholinergic neurons against ROS generation induced by Aβ_1–42.

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TQ attenuated Aβ_1–42 – induced synaptic toxicity.

Neuromodulatory Effect of Thymoquinone in Attenuating Glutamate-Mediated Neurotoxicity Targeting the Amyloidogenic and Apoptotic Pathways

Overexposure of the glutamatergic N-methyl-d-aspartate (NMDA) receptor to the excitatory neurotransmitter l-glutamic acid leads to neuronal cell death by excitotoxicity as a result of increased intracellular Ca²⁺, mitochondrial dysfunction, and apoptosis. Moreover, it was previously reported that prolonged activation of the NMDA receptor increased beta-amyloid (Aβ) levels in the brain. Thymoquinone (TQ), the active constituent of Nigella sativa seeds, has been shown to have potent antioxidant and antiapoptotic effects. The aim of the present study was to explore the neuromodulatory effects of different doses of TQ (2.5 and 10 mg/kg) against apoptotic cell death and Aβ formation resulting from glutamate administration in rats using vitamin E as a positive control. Behavioral changes were assessed using Y-maze and Morris water maze tests for evaluating spatial memory and cognitive functions. Caspase-3, Lactate dehydrogenase, Aβ-42, and cytochrome c gene expression were determined. TQ-treated groups showed significant decreases in the levels of all tested biochemical and behavioral parameters compared with the glutamate-treated group. These findings demonstrated that TQ has a promising neuroprotective activity against glutamate-induced neurotoxicity and this effect is mediated through its anti-amyloidogenic, antioxidant, and antiapoptotic activities.

Dissecting the Potential Roles of Nigella sativa and Its Constituent Thymoquinone on the Prevention and on the Progression of Alzheimer's Disease

Several nutraceuticals have been investigated for preventing or retarding the progression of different neurodegenerative diseases, including Alzheimer's disease (AD). Because Nigella sativa (NS) and its isolated compound thymoquinone (TQ) have significant anti-oxidant and anti-inflammatory proprieties, they could represent effective neuroprotective agents. The purpose of this manuscript is to analyze and to recapitulate the results of in vitro and in vivo studies on the potential role of NS/TQ in AD's prevention and treatment. The level of evidence for each included animal study has been assessed by using a modified CAMARADES (Collaborative Approach to Meta-Analysis and Review of Animal Data from Experimental Studies) 10-item checklist. We used MEDLINE and EMBASE databases to screen relevant articles published up to July 2017. A manual search was also performed. The database search yielded 38 studies, of which 18 were included in this manuscript. Results from these approaches suggest that NS or TQ could represent an effective strategy against AD due to the balancing of oxidative processes and the binding to specific intracellular targets. The overall effects mainly regard the prevention of hippocampal pyramidal cell loss and the increased cognitive functions.

Senile Dementia from Neuroscientific and Islamic Perspectives

Diseases involving the nervous system drastically change lives of victims and commonly increase dependency on others. This paper focuses on senile dementia from both the neuroscientific and Islamic perspectives, with special emphasis on the integration of ideas between the two different disciplines. This would enable effective implementation of strategies to address issues involving this disease across different cultures, especially among the world-wide Muslim communities. In addition, certain incongruence ideas on similar issues can be understood better. The former perspective is molded according to conventional modern science, while the latter on the analysis of various texts including the holy Qur'an, sunnah [sayings and actions of the Islamic prophet, Muhammad (pbuh)] and writings of Islamic scholars. Emphasis is particularly given on causes, symptoms, treatments and prevention of dementia.

Neuroprotective effects of Nigella sativa extract upon the hippocampus in PTU-induced hypothyroidism juvenile rats: A stereological study

This study aimed to examine the neuroprotective effects of Nigella sativa (N. sativa) in the hippocampus of propylthiouracil (PTU)-induced hypothyroid rats during neonatal and juvenile growth. Twenty- five pregnant rats from early gestation (GD 0) were divided into five groups: (1) control (received drinking water), (2) PTU (received 0.005% PTU in drinking water), (3-5) PTU + NS 0.05%, PTU + NS 0.1%, PTU + NS 0.2% (along with PTU, received 0.05%, 0.1% and 0.2% W/V of N. sativa respectively) and treatment continued until postnatal day 60 (PN 60). The brains of male pups were removed for histological and stereological assessments. N. sativa extract significantly reduced the production of dark neurons and apoptotic cells in different areas of the hippocampus compared to the PTU group. Moreover, it significantly attenuated the effect of hypothyroidism on the volume reduction of the hippocampus. The results of the present study suggested that N. sativa extract has a potential ability to prevent the hippocampal neural damage after inducing hypothyroidism during neonatal and juvenile growth in rats.

Neurochemical and behavioral effects of Nigella sativa and Olea europaea oil in rats

OBJECTIVES

In the last few decades, therapeutic uses of medicinal compounds present in food as a normal constituent has risen substantially, largely because of their fewer side effects and adequate efficacy. This study is designed to investigate a role of brain serotonin (5-HT) and dopamine (DA) in the potential nootropic, anxiolytic, and other beneficial effects of Nigella sativa (NS) and Olea europaea (OE) oil in rat models.

METHODS

Animals were treated with NS and OE oil orally at doses of 0.1 ml/kg and 0.25 ml/kg for 5 weeks. Food intake and body weight change, anxiety-like effects in elevated plus maze and activity in a novel and familiar environment were monitored weekly. Effects on learning and memory after 5 weeks treatment were monitored using Morris water maze test. Neurochemical analysis was carried using HPLC-ECD method.

RESULTS

NS and OE oil administration enhanced learning and memory in Morris water maze test and the effects were greater in NS than OE oil-treated animals. Low dose of OE oil increased exploration in an open field, higher dose of OE oil and both doses of NS oil produced no consistent effect on open field exploration. Effects of both oils on anxiety-like behavior, food and water intake, and activity in activity box were either not consistent or did not occur. The treatment increased homovanillic acid (HVA). 5-HT levels increased in high dose of NS oil and low dose of OE oil-treated groups. Low dose NS oil decreased 5-HT.

DISCUSSION

The present study suggests that active components in NS and OE oil may prove useful in treating impaired cognition. OE oil may produce psychostimulant-like effect. Modulation of DA and serotonin neurotransmission seems important in the pharmacological effect of these oils.

The effects of Nigella sativa extract on hypothyroidism-associated learning and memory impairment during neonatal and juvenile growth in rats

OBJECTIVES

It has been shown that hypothyroidism-induced oxidative damage in brain tissue is involved in its adverse effects on learning and memory. Nigella sativa (N. sativa) has been suggested to have antioxidant and neuroprotective effects. The objective of this study was to investigate the effects of hydroalcoholic extract of N. sativa on hypothyroidism-associated learning and memory impairment during neonatal and juvenile growth in rats.

METHODS

Thirty pregnant rats were kept in separate cages. After delivery, the mothers and their offspring were randomly divided into six groups including: (1) control, (2) PTU (propylthiouracil), (3) PTU-NS 100, (4) PTU-NS 200, (5) PTU-NS 400, and (6) PTU-Vit C (vitamin C). All dams except the control group received 0.005% PTU in their drinking water during lactation. Besides PTU, dams in groups 3, 4, 5, and 6 received 100, 200, and 400 mg/kg N. sativa extract, or 100 mg/kg Vit C, respectively. After lactation period, pups continued to receive same experimental treatment for the first 8 weeks of their life. Then, 10 male offspring of each group were randomly selected and assessed for the learning and memory abilities by using Morris water maze (MWM) and passive avoidance (PA) tests. Blood samples were collected for thyroxine assessment, animals were euthanized, and the brain tissues were removed and analyzed for total thiol groups and malondialdehyde (MDA) concentrations.

RESULTS

PTU exposure significantly increased the time latency in MWM test, while reduced the time spent in target quadrant, and decreased the latency for entering the dark compartment in PA test. These effects were associated with significant reduction in serum thyroxine levels and brain levels of thiol groups, and significant elevation in hippocampal MDA. Administration of 400 mg/kg N. sativa extract and 100 mg/kg Vit C reduced the time latency, while increased the time spent in target quadrant compared to the PTU group in MWM test. Treatment by 100-400 mg/kg of N. sativa extract and also Vit C significantly increased the time latency for entering the dark compartment in PA test. The serum thyroxine concentrations of the animals treated by all doses of the N. sativa extract as well as by Vit C were higher than that of the PTU group. Two hundred and four hundred milligrams/kilogram of NS extract and 100 mg/kg Vit C decreased the MDA concentration in hippocampal tissues, while increased thiol contents compared to the PTU group.

DISCUSSION

The results of this study demonstrate that the hydroalcoholic extract of N. sativa have protective effects on hypothyroidism-associated learning and memory impairment during neonatal and juvenile growth in rats. The effects were comparable to Vit C and might be due to the protective effects of N. sativa extract against brain tissues' oxidative damage.

The Role of Nigella sativa and Its Active Constituents in Learning and Memory

The loss of the ability for learning and memory is a prominent feature of dementia, which affects millions of individuals all over the world, due to either neurodegenerative diseases or brain injury. Although a lot of information is known about the pathology involved, treatment remains elusive at best. The Black Seed of Nigella sativa has been historically and religiously used for thousands of years for preventing and treating many different kinds of diseases. This review article looks at Nigella sativa and its potential role in facilitating learning and memory. The possible use of this seed's extract or compounds isolated from it, such as thymoquinone, for treating damaged brain neural tissue is discussed. The evidence presented in this paper appears to be supporting the hypothesis that this plant and/or its bioactive constituents can enhance learning and memory in health and disease in animals and humans.

The Effects of Inhaled Pimpinella peregrina Essential Oil on Scopolamine-Induced Memory Impairment, Anxiety, and Depression in Laboratory Rats

In the present study, we identified the effects of inhaled Pimpinella peregrina essential oil (1 and 3 %, for 21 continuous days) on scopolamine-induced memory impairment, anxiety, and depression in laboratory rats. Y-maze and radial arm-maze tests were used for assessing memory processes. Also, the anxiety and depressive responses were studied by means of the elevated plus-maze and forced swimming tests. The scopolamine alone-treated rats exhibited the following: decrease of the spontaneous alternation percentage in Y-maze test, increase of the number of working and reference memory errors in radial arm-maze test, along with decrease of the exploratory activity, the percentage of the time spent and the number of entries in the open arm within elevated plus-maze test and decrease of swimming time and increase of immobility time within forced swimming test. Inhalation of the P. peregrina essential oil significantly improved memory formation and exhibited anxiolytic- and antidepressant-like effects in scopolamine-treated rats. Our results suggest that the P. peregrina essential oil inhalation ameliorates scopolamine-induced memory impairment, anxiety, and depression. Moreover, studies on the P. peregrina essential oil may open a new therapeutic window for the prevention of neurological abnormalities closely related to Alzheimer's disease.

Neuropharmacological effects of Nigella sativa

Nigella sativa (NS) (Ranunculaceae family) is generally utilized as a therapeutic plant all over the world. The seeds of the plant have a long history of use in different frameworks of medicines and food. In Islamic literature, it is considered as one of the greatest forms of therapeutics. It has been widely used to treat nervous system diseases such as memory impairment, epilepsy, neurotoxicity, pain, etc. Additionally, this is uncovered that the majority of therapeutic properties of this plant are due to the presence of thymoquinone (TQ) which is a major bioactive component of the essential oil. Pharmacological studies have been done to evaluate the effects of NS on the central nervous system (CNS). The present review is an effort to provide a detailed scientific literature survey about pharmacological activities of the plant on nervous system. Our literature review showed that NS and its components can be considered as promising agents in the treatment of nervous system disorders.

The Effects of Nigella Sativa Hydro-alcoholic Extract on Memory and Brain Tissues Oxidative Damage after Repeated Seizures in Rats

Regarding the therapeutic properties of Nigella sativa (NS), the effects of the plant hydro - alcoholic extract on learning, memory and brain tissues oxidative damage were investigated in penthylenetetrazole (PTZ) - induced repeated seizures. There were 4 experimental groups including: 1- control group; received saline, 2- PTZ group ; received saline and PTZ (50 mg/Kg, i.p) , 3-PTZ- NS 200 and 4- PTZ- NS 400 ; received 200 and 400 mg/Kg of NS extract respectively, before PTZ injection in 5 consecutive days. Seizure scores were lower in PTZ - NS 200 and 400, furthermore the seizure onset latencies were higher in these groups than PTZ group (P<0.05 and P<0.01 ). In Morris water maze, the time spent in target quadrant by PTZ group was lower than control group (P<0.05); while, 400 mg/Kg of the extract increased it (P<0.01). In the passive avoidance test, delay time to enter the dark by PTZ group was lower than control at 1 and 24 hours after training (P<0.01- P<0.001); while, 400 mg/Kg of the extract increased it (P<0.05). The total thiol concentration in hippocampal and cortical tissues of PTZ group was reduced while, MDA concentration was higher than control (p<0.05 - p<0.001). Administration of the extract increased the total thiol and decreased the MDA concentrations (p<0.01- p<0.001). It is concluded that the hydro-alcoholic extract of NS possess beneficial effects on learning and memory impairments in repeated seizures model which is accompanied by antioxidant effects in the brain.