Beneficial effects of Urtica dioica on scopolamine-induced memory impairment in rats: protection against acetylcholinesterase activity and neuronal oxidative damage

Neuroprotective Effects of Dehydroepiandrosterone and Hericium erinaceus in Scopolamine-induced Alzheimer's Diseases-like Symptoms in Male Rats

BACKGROUND

The neuroprotective effects of Dehydroepiandrosterone (DHEA) and Hericium erinaceus (H. erinaceus) mushroom extract against scopolamine-induced Alzheimer's disease-like symptoms in male Wistar rats were investigated.

METHODS

Sixty-four male Wistar rats were divided into eight groups (n = 8). Scopolamine (SCO) was intraperitoneally injected at a dose of 1 mg/kg/day for 10 days. The treatment groups orally received DHEA (250 mg/kg/day) and/or H. erinaceus (300 mg/kg/day) for 14 days. Afterward, the Morris water maze (MWM) and novel object recognition tests were implemented. Then, animals were anesthetized and the brain tissue samples were separated. Levels of lipid peroxidation (LPO), total antioxidant capacity (TAC), catalase activity (CAT), and brain-derived neurotrophic factor (BDNF) were determined. Also, histopathological studies were evaluated in the brain tissue samples.

RESULTS

Administration of SCO significantly decreased spatial and cognitive memory (p < 0.001). Not only did SCO injection significantly increase the levels of the LPO but also the SCO markedly reduced the levels of the TAC, CAT activity, and the BDNF in the brain tissue. On the other hand, a combination of the DHEA and H. erinaceus showed higher efficacy than the DHEA or H. erinaceus in attenuating behavioral anomalies and improving the antioxidant defense system and BDNF levels. Histological examination was well correlated with biochemical findings regarding SCO neurodegeneration and DHEA and/or H. erinaceus neuroprotection.

CONCLUSION

Interestingly, ADHE and/or H. erinaceus may due to their potential neurotrophic properties be used as a new and beneficial concurrent therapy in the treatment of Alzheimer's disease-like symptoms caused by SCO.

The role of stinging nettle (Urtica dioica L.) in the management of rotenone-induced Parkinson's disease in rats

Parkinson's disease (PD) is one of the most common neurodegenerative conditions. Alpha-synuclein deposition, Lewy bodies (LBs) formation, disruption of the autophagic machinery, apoptosis of substantia nigra dopaminergic neurons, oxidative stress, and neuroinflammation are all pathologic hallmarks of PD. The leaves of the stinging Nettle (Urtica dioica L.) have a long history as an herbal cure with antioxidant, anti-inflammatory, anti-cancer, immunomodulatory, and neuroprotective properties. The current study aims for the first time to investigate the role of Nettle supplementation on Rotenone-induced PD. Rats were divided into five groups; a Saline control, Nettle control (100 mg/kg/day), Rotenone control (2 mg/kg/day), Rotenone + Nettle (50 mg /kg/day), and Rotenone + Nettle (100 mg/kg). After four weeks, the rats were examined for behavioral tests. The midbrains were investigated for histopathological alteration and immunohistochemical reaction for Tyrosine hydroxylase in the dopaminergic neurons, α-synuclein for Lewy bodies, caspase 3 for apoptotic neurons, LC3 and P62 for autophagic activity. Midbrain homogenates were examined for oxidative stress markers. mRNA expression of TNFα and Il6; inflammatory markers, Bcl-2, BAX and Caspase 3; apoptosis markers, were detected in midbrains. The results showed that Nettle caused recovery of midbrain dopaminergic neurons, by inhibiting apoptosis, inflammation, and oxidative stress and by restoring the autophagic machinery with clearance of α-synuclein deposits. We can conclude that Nettle is a potentially effective adjuvant in the treatment of Parkinson's disease.

Protective effects of Urtica dioica on the cerebral cortex damage induced by Potassium bromate in adult male albino rats

Potassium bromate is used in cheese production, beer making and is also used in pharmaceutical and cosmetic. It is a proven carcinogen as it is a strong oxidizing agent that generates free radicals during xenobiotic metabolism. Urtica dioica (Ud) (from the plants' family of Urticaceae) is a plant that has long been used as a medicinal plant in many parts of the world. It has been shown to have anti-inflammatory, antioxidant and immunosuppressive properties. So, this study aimed to clarify the effect of Potassium bromate on the histological structure of cerebral cortex of adult male albino rats, evaluate the possible protective role of Urtica dioica. Thirty adult healthy male albino rats were divided into three groups; group I (Control group), group II (KBrO3 treated group). Group III (KBrO3 and Urtica dioica treated group).At the end of the experiment, rats in all groups were anesthetized and specimens were processed for light and electron microscope. Morphometric and statistical analyses were also performed. Nerve cells of the treated group showed irregular contours, dark nuclei, irregular nuclear envelopes, dilated RER cisternae, and mitochondria with ruptured cristae. Vacuolated neuropil was also observed. Immunohistochemically, stained sections for GFAP showed strong positive reaction in the processes of astrocytes. Recovery group showed revealed nearly the same as the histological picture as the control group. In conclusion, potassium bromate induces degenerative effects on neurons of cerebral cortex and urtica dioica provide an important neuroprotective effects against these damaging impacts through their antioxidant properties.

Omega-3 fatty acids prevent nicotine withdrawal-induced impairment of learning and memory via affecting oxidative status, inflammatory response, cholinergic activity, BDNF and amyloid-B in rat hippocampal tissues

In the present study, the main objective was to reveal whether treatment by Omega-3 fatty acids could prevent the adverse effects of adolescent nicotine withdrawal on spatial and avoidance memory in male rats. For this purpose, Morris water maze and passive avoidance tests were performed on male Wistar rats and the hippocampal levels of oxidative stress markers, inflammatory indices, brain-derived neurotrophic factor, nitrite, amyloid-B and acetylcholinesterase (AChE) were measured. Moreover, density of dark neurons were assessed in CA1 and CA3 regions. Results showed that adolescent nicotine exposure followed by a period of drug cessation exacerbates the behavioral indices of learning and memory through affecting a variety of biochemical markers within the hippocampal tissues. These changes lead to elevation of oxidative and inflammatory markers, reduction of neurotrophic capacity and increased AChE activity in hippocampal tissues. In addition, it was observed that co-administration of nicotine with Omega-3 fatty acids significantly prevents nicotine withdrawal-induced adverse effects through restoration of the mentioned biochemical disturbances. Therefore, we suggest administration of Omega-3 fatty acids as a safe, inexpensive and effective therapeutic strategy for prevention of memory dysfunctions associated with nicotine abstinence during adolescence.

Protective effects of cinnamon on acetylcholinesterase activity and memory dysfunction in diabetic rats

OBJECTIVES

Regarding neurocognitive and immunomodulatory properties of cinnamon (Cinn) we aimed to investigate whether cinnamon regulates acetylcholinesterase (AChE) activity, and oxidative abnormalities with concomitant memory dysfunction in streptozotocin (STZ)-induced diabetes.

METHODS

Forty-seven male adult rats were divided into seven groups (n=8 animals): Control group: in these non-diabetic rats only saline 0.9% NaCl was gavaged, Diabetic (Dia) group: diabetic rats in them saline 0.9% NaCl was gavaged for six weeks. Dia-Cinn 100, Dia-Cinn 200, and Dia-Cinn 400, Dia-Met groups: in these diabetic rats the extract (100, 200, 400 mg/kg respectively) or metformin (300 mg/kg) was gavaged for six weeks. Passive avoidance performance, AChE enzyme activity, and oxidative indicators were examined among the groups.

RESULTS

Vs. the control group, blood glucose level and stay time in the dark were remarkably increased in Dia group whereas the latency time was decreased. Meanwhile, antioxidant levels (superoxide dismutase, catalase, and thiols) noticeably decreased in the Dia group compared to the Control group. On the other hand, Cinn extract espicailly at the highest dose recovered the changes similar to those found in the metformin-treated group.

CONCLUSIONS

These findings proposed that the cinnamon hydro-ethanolic extract promotes memory recovery in diabetic conditions through the atteuation of the AChE activity and oxidative injury.

The modulator role of Urtica dioica on deleterious effects of retinoic acid high doses on histological parameters and fertilization of rats

Aim

This study purposed to evaluate the modulator and protective role of Urtica dioica (UD) extract against deleterious effects of retinoic acid (RA) high doses on histological parameters and fertilization of rats.

Materials and methods

For the in-vivo phase, 60 female Wistar rats were divided into 6 identical groups as 1) control, 2) 25 mg/kg RA, 3) 25 mg/kg UD extract, 4) 50 mg/kg UD extract, 5) UD extract (25 mg/kg) + RA (25 mg/kg), and 6) UD extract (50 mg/kg) + RA (25 mg/kg). Biochemical parameters, including luteinizing hormone (LH), folliclestimulating hormone (FSH), malondialdehyde (MDA) levels, superoxide dismutase (SOD), and catalase (CAT) activities, were measured. In the in-vitro phase, oocytes were obtained from 10 female rats without injection. In addition to the mentioned parameters, histological parameters (oocytes in various stages) and the results of IVM, IVF, and embryo developments were assessed and compared among the groups with the use of one-way ANOVA and Tukey's post hoc tests.

Results

The high dosage of RA significantly reduced the LH and FSH levels; however, UD alone and with RA increased the hormone levels in rats. Regarding the reactive oxygen species (ROS) activity levels in rats' blood samples, RA increased the MDA and decreased the SOD and CAT levels. Treatment with UD extract (UD + RA groups) significantly improved the parameters mentioned, showing UD's antioxidant effect. The rate of oocyte maturation, 2-cell-4-cell and 4-cell-8-cell embryos, and blastocyst formation increased significantly in the groups in which UD extracts were administered compared to the control and RA groups. Furthermore, the increases were significant in the UD + RA groups compared to the RA group.

Conclusion

UD extract can significantly reduce RA high doses side effects on histological parameters and fertilization of rats and has the protective potential against RA deleterious effects.

The medicinal chemistry of Urtica dioica L.: from preliminary evidence to clinical studies supporting its neuroprotective activity

Urtica dioica is a perennial herb from the family of Urticaceae that is commonly known as stinging nettle. This plant is widespread in Europe, Africa, America, and a part of Asia, as it adapts to different environments and climatic conditions. The leaves, stalk, and bark of U. dioica found applications in the field of nutrition, cosmetics, textile, pest control and pharmacology. In this connection, bioactive chemical constituents such as flavonoids, phenolic acids, amino acids, carotenoids, and fatty acids have been isolated from the plant. With this review, we aim at providing an updated and comprehensive overview of the contributions in literature reporting computational, in vitro, pre-clinical and clinical data supporting the therapeutic applications of U. dioica. Experimental evidence shows that U. dioica constituents and extracts can provide neuroprotective effects by acting through a combination of different molecular mechanisms, that are discussed in the review. These findings could lay the basis for the identification and design of more effective tools against neurodegenerative diseases.

Therapeutic effects of Rosa canina, Urtica dioica and Tanacetum vulgare herbal combination in treatment of tinnitus symptoms: A double-blind randomised clinical trial

OBJECTIVE

To evaluate the effect of Neurotec® herbal capsule (100 mg twice a day for 3 months) on the tinnitus symptoms in comparison with the placebo.

DESIGN

A double-blind randomised clinical trial.

SETTING

Otolaryngology clinic of Baqiyatallah Hospital.

PARTICIPANTS

Patients suffering from subjective tinnitus.

MAIN OUTCOME MEASURES

Pure tone audiometry was measured at .5, 1, 2, 4 and 6 kHz frequencies before and after the third month of intervention. In addition, Tinnitus Handicap Inventory (THI) questionnaire as well as visual analogue scale (VAS) for tinnitus loudness, daily annoyance, daily life or sleep disturbance, daily perception and mood alteration were evaluated.

RESULTS

Finally, 103 (69 males and 34 females) patients with a mean age of 51.33 ± 13.91 years were analysed. In contrast with control group, patients in intervention group showed a remarkable decrease in THI score after 3 months of treatment (p < .05). Although both groups had improvements in VAS scores, mood disturbance, daily tinnitus perception and daily life alteration scores were only improved in the intervention group. The mean pure tone air and bone conduction were not significantly different between the control and the intervention group at baseline and 3 months after the intervention at .5, 1, 2 and 4 kHz (p > .05).

CONCLUSION

A 3-month treatment with Neurotec capsules in addition to patient education is of benefit for managing symptoms in patients with chronic tinnitus.

Vitamin B12 administration prevents ethanol-induced learning and memory impairment through re-establishment of the brain oxidant/antioxidant balance, enhancement of BDNF and suppression of GFAP

There are growing evidence indicating that the adolescent brain is persistently affected by the use of psychostimulant agents. In this regard, alcohol drinking has become rather common among the adolescents in many societies during the last decade. It is currently well known that long-term ethanol exposure deteriorates various cognitive functions such as learning and memory. Mechanistically, these adverse effects have been shown to be mediated by oxidative damage to central nervous system. On the other hand, Vit-B12 is known to improve cognitive performance by suppression of oxidative parameters. Thus, in the present study we aimed to test whether treatment by Vit-B12 could prevent ethanol-induced complications in mice using behavioral and biochemical methods. Different groups of male Syrian mice received ethanol, ethanol+Vit-B12, Vit-B12 alone, or saline during adolescence and then learning and memory functions were assessed by Morris water maze (MWM) and Passive Avoidance (PA) tests. Finally, mice were sacrificed for measurement of biochemical factors. Results indicated that, adolescent ethanol intake impairs learning and memory function through exacerbation of oxidative stress and Vit-B12 treatment improves these complications by re-establishment of oxidant/anti-oxidant balance in CNS. Moreover, we found that Vit-B12 prevents ethanol-induced reduction of BDNF and enhancement of GFAP and acetylcholinesterase (AChE) activity. In conclusion, it seems that Vit-B12 supplementation could be used as an effective therapeutic strategy to prevent learning and memory defects induced by chronic alcohol intake during adolescence.

Minocycline alleviated scopolamine-induced amnesia by regulating antioxidant and cholinergic function

Background and aim

Minocycline, a tetracycline derivative, has been found to exert neuroprotective properties. The current project aimed to assess the antioxidant status and cholinergic function in the amnesia induced by scopolamine.

Methods

We evaluated the passive avoidance performance, acetylcholine esterase (AChE) enzyme activity, and the oxidative stress indicators in the following groups: Normal control, scopolamine, and the treatment groups (the animals were given minocycline (10-30 mg/kg)).

Results

Scopolamine (intraperitoneal) injection was associated with impairment of passive avoidance performance and neurotoxicity. Minocycline pronouncedly ameliorated scopolamine injury as presented by the increased latency time to darkness and stay time in lightness along with the decreased darkness entry. Moreover, minocycline decreased lipid peroxidation, while it elevated the levels of superoxide dismutase, AChE enzymes, and thiol groups in both the cortex and hippocampus.

Conclusion

Our data suggested that minocycline modulated the antioxidant status and AChE in the brains, which may contribute to its protective effects against scopolamine-induced amnesia.

Antioxidant Activity of Urtica dioica: An Important Property Contributing to Multiple Biological Activities

Urtica dioica (UD) is a multi-functional plant known to be used as both food and medicine from ancient times. The plant has the potential to be used as a fertilizer and for biological pest control. It is also used in textile and related industries for its quality fibers. In the recent past, the plant has received great attention for its numerous important biological activities and food applications. The antioxidant activity of UD is the crucial factor supporting its important biological activities, such as anticancer, antidiabetic and anti-inflammatory properties. The antioxidant activity of UD is also found to be protective in different organs, including the brain, liver, lungs, kidney, ovary, and uterus, and may also be protective against diseases associated with these organs. Few clinical studies have endorsed the antioxidant potential of UD in patients. The current work is an attempt to comprehensively compile and discuss the antioxidant activity of UD from in vitro, in vivo and human studies. The insights of the current study would be helpful in getting a panoramic view of the antioxidant potential of UD, and provide direction for optimizing and developing it for therapeutic applications against important diseases and conditions in the near future.

PPARγ activation improved learning and memory and attenuated oxidative stress in the hippocampus and cortex of aged rats

Oxidative stress has an important role in brain aging and its consequences include cognitive decline and physiological disorders. Peroxisome proliferator-activated receptor-γ (PPARγ) activation has been suggested to decrease oxidative stress. In the current research, the effect of PPARγ activation by pioglitazone(Pio) on learning, memory and oxidative stress was evaluated in aged rats. The rats were divided into five groups. In the Control group, vehicle (saline-diluted dimethyl sulfoxide (DMSO)) and saline were injected instead of Pio and scopolamine (Sco), respectively. In the Sco group, the vehicle was injected instead of Pio and the rats were injected by Sco 30 min before the behavioral tests. In the Sco-Pio 10, Sco-Pio 20, and Sco-Pio 30 groups, 10, 20, and 30 mg/kg Pio was injected and finally, the rats were injected with Sco 30 min before the behavioral tests. Morris water mater maze(MWM) and passive avoidance(PA) tests were carried out, and finally, the hippocampus and cortex were removed for biochemical assessments. The results showed that the highest dose of Pio decreased the traveling time and distance during 5 days of learning and increased the time and distance in the target area on the probe day of MWM. The highest dose of Pio also prolonged the delay time for entering the dark and total time spent in the light while decreasing the total time spent in and the number of entries into the dark in PA test. Pio especially, in the medium and highest doses, decreased MDA while increasing thiol, superoxide dismutase, and catalase in the hippocampus and cortex. It is concluded that PPARγ activation by Pio as an agonist improved learning and memory in aged rats probably by attenuating oxidative stress in the hippocampus and cortex.

Stinging Nettle (Urtica dioica L.): Nutritional Composition, Bioactive Compounds, and Food Functional Properties

Stinging nettle (Urtica dioica L., Urticaceae) is commonly found in Asia, Africa, and Europe and has a long history of being used as food and traditional medicine. Recently, this plant is gaining attention as a highly nutritious food, where fresh leaves are dried and used as powder or in other forms. Leaves are rich in many bioactive compounds. This review aims to cover the traditional uses in food and medicine, as well as its nutritional composition, including its bioactive chemical constituents and reported food functional activities. Various bioactive chemical constituents have been isolated from stinging nettle to date, such as flavonoids, phenolic acids, amino acid, carotenoids, and fatty acids. Stinging nettle extracts and its compounds, such as rutin, kaempferol, and vitamin A, are also used for their nutritional properties and as anti-inflammatory and antioxidant agents. Future studies should focus on the proper formulation and stability testing of the functional foods containing stinging nettle and their detailed activities in clinical studies.

A multi-parameter evaluation of the neuroprotective and cognitive-enhancing effects of Origanum onites L. (Turkish Oregano) essential oil on scopolamine-induced amnestic rats

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by progressive deterioration of cognitive functions (dementia) and represents a growing public health concern since the population in the age groups at risk is increasing. The latter raises an urgent need to translate research findings in the basic brain and behavioral sciences into anti-AD drugs and disease-modifying therapies. Origanum onites (L.), also called Turkish oregano, is a perennial and herbaceous plant species grown for centuries for medicinal, cosmetic and culinary purposes. This is the first study to investigate the putative neuroprotective and pro-cognitive activities of O. onites essential oil (OOEO) against scopolamine-induced amnesia of AD-type in Wistar albino rats. The results of behavioral tests revealed that OOEO administration was able to significantly alleviate learning and memory impairments induced by scopolamine in vivo. The observed effects could be attributed to inhibition of acetylcholinesterase activity, attenuation of oxidative stress and prevention of neuronal apoptosis in the hippocampus and frontal cortex of AD rats. Modulation of pro-inflammatory enzymes, including cyclooxygenase-2, inducible nitric oxide synthase and myeloperoxidase, might further contribute to the neuroprotective properties of OEOO, as predicted by our in silico models. These findings offer novel insights into the therapeutic potential of OEOO in patients with AD.

Effect of Sanguisorba minor on scopolamine-induced memory loss in rat: involvement of oxidative stress and acetylcholinesterase

Sanguisorba minor (S. minor) has neuroprotective and antioxidant activities. However, its potential benefits in ameliorating learning and memory functions have been explored in no studies up to now. So, in the current study, rats were treated with S. minor hydro-ethanolic extract (50, 100, and 200 mg/kg, intraperitoneal (i.p.)) as well as rivastigmine (0.5 mg/kg, i.p.) for 21 consecutive days. Thereafter, their behavioral performance was assessed using Morris water maze (MWM) and passive avoidance (PA) tasks. Notably, 30 min before conducting the tasks, scopolamine was injected. Finally, the biochemical assessments were done using the brain tissue. The extract characterization was performed by liquid chromatography-mass spectrometry, which confirmed the presence of quercetin, myricetin, kaempferol, catechin, ellagic acid, and gallic acid derivatives. In the MWM test, the extract reduced both escape latency and the travelled distance, compared to the scopolamine group. Moreover, in the PA test, the latency to enter the dark chamber significantly increased by the extract, compared to the scopolamine group (p < 0.05-p < 0.001). Notably, the beneficial effects of S. minor on cognitive performance of the scopolamine-treated rats appeared to be similar or even better than rivastigmine in behavior performance. Similar to rivastigmine, it was observed that the extract attenuated both AChE activity and oxidative injury in the brain as evidenced by the increased antioxidant enzymes and total thiol content; however, it decreased malondialdehyde level (p < 0.05-p < 0.001). In conclusion, the results suggested the effectiveness of S. minor in preventing cognitive dysfunction induced by scopolamine. Accordingly, these protective effects might be produced by the regulation of cholinergic activity and oxidative stress. S. minor could be considered as a potential alternative therapy in cognition disorders.

Antiamnesic and Neuroprotective Effects of an Aqueous Extract of Ziziphus jujuba Mill. (Rhamnaceae) on Scopolamine-Induced Cognitive Impairments in Rats

Background

Alzheimer's disease is a neurological condition that affects about 44 million people worldwide. The available treatments target symptoms rather than the underlying causes. Ziziphus jujuba (Rhamnaceae) is widely used in traditional Cameroonian medicine to treat diabetes, pain, infections, and dementia. Previous studies reported that Z. jujuba aqueous macerate improves working memory impairment, but no study on the antiamnesic effect of a concoction of Z. jujuba in rats has been performed. Therefore, this study aimed to assess the antiamnesic and neuroprotective effects of an aqueous extract of Z. jujuba on scopolamine-induced cognitive impairments in rats.

Methods

Learning and memory impairments were induced in rats by administering scopolamine (1 mg/kg, i.p.) to 58 rats for 15 days. Rats that developed learning and memory impairments in Morris water maze and Y-maze paradigms were divided into 7 groups (8 rats each) and treated daily for 15 days as follows: the normal control group received distilled water (10 ml/kg, p.o.), the negative control group received distilled water (10 ml/kg, p.o.), positive control groups either received donepezil (1.2 mg/kg, p.o.) or tacrine (10 mg/kg, p.o.), and the three test groups were given the extract (29, 57, and 114 mg/kg, p.o.). At the end of treatments, learning and memory impairments were determined using the same paradigms. Animals were then euthanized, and biochemical parameters of oxidative stress, inflammation, and apoptosis were analyzed in the hippocampus and prefrontal cortex.

Results

On the 4th day of the acquisition phase in the Morris water maze, Z. jujuba (29 and 114 mg/kg) reduced (p < 0.001) the latency to reach the platform, while in the retention phase, Z. jujuba (57 and 114 mg/kg) decreased (p < 0.001) the time to reach the platform and increased the time in the target quadrant (p < 0.05) compared to control. Surprisingly, the extract failed to affect spontaneous alternations in the Y-maze. Furthermore, the extract (29, 57, and 114 mg/kg) reversed (p < 0.001) scopolamine-induced oxidative stress, inflammation, and apoptosis. This was supported by the reduction of neuronal alterations in the hippocampus and prefrontal cortex.

Conclusions

Compared to donepezil, a standard drug against Alzheimer's disease, these findings suggest that Z. jujuba extract possesses antiamnesic and neuroprotective effects, and these effects are mediated in part through antioxidant, anti-inflammatory, and antiapoptotic activities. These findings help to explain its use in treating psychiatric disorders in Cameroon's folk medicine.

Exercise and Urtica dioica extract ameliorate hippocampal insulin signaling, oxidative stress, neuroinflammation, and cognitive function in STZ-induced diabetic rats

INTRODUCTION

Diabetes mellitus is related to cognitive impairments and molecular abnormalities of the hippocampus. A growing body of evidence suggests that Urtica dioica (Ud) and exercise training (ET) have potential therapeutic effects on diabetes and its related complications. Therefore, we hypothesized that the combined effect of exercise training (ET) and Ud might play an important role in insulin signaling pathway, oxidative stress, neuroinflammation, and cognitive impairment in diabetic rats.

METHODS

Forty animals were divided into five groups (N = 8): healthy-sedentary (H-sed), diabetes-sedentary (D-sed), diabetes-exercise training (D-ET), diabetes-Urtica dioica (D-Ud), diabetes-exercise training-Urtica dioica (D-ET-Ud). Streptozotocin (STZ) (Single dosage; 45 mg/kg, i.p.) was used to induce diabetes. Then, ET (moderate intensity/5day/week) and Ud extract (50 mg/kg, oral/daily) were administered for six weeks. We also investigated the effects of ET and Ud on cognitive performance (assessed through Morris Water Maze tests), antioxidant capacity, and lipid peroxidation markers in hippocampus. Furthermore, we measured levels of insulin sensitivity and signaling factors (insulin-Ins, insulin receptor-IR and insulin-like growth factor-1 receptor-IGF-1R), and neuroinflammatory markers (IL-1 β, TNF-α). This was followed by TUNEL assessment of the apoptosis rate in all regions of the hippocampus.

RESULTS

D-sed rats compared to H-sed animals showed significant impairments (P < 0.001) in hippocampal insulin sensitivity and signaling, oxidative stress, neuroinflammation, and apoptosis, which resulted in cognitive dysfunction. Ud extract and ET treatment effectively improved these impairments in D-ET (P < 0.001), D-Ud (P < 0.05), and D-ET-Ud (P < 0.001) groups compared to D-sed rats. Moreover, diabetes mediated hippocampal oxidative stress, neuroinflammation, insulin signaling deficits, apoptosis, and cognitive dysfunction was further reversed by chronic Ud+ET administration in D-ET-Ud rats (P < 0.001) compared to D-sed animals.

CONCLUSIONS

Ud extract and ET ameliorate cognitive dysfunction via improvement in hippocampal oxidative stress, neuroinflammation, insulin signaling pathway, and apoptosis in STZ-induced diabetic rats. The results of this study provide new experimental evidence for using Ud+ET in the treatment of hippocampal complications and cognitive dysfunction caused by diabetes.

Beneficial effects of angiotensin converting enzyme inhibition on scopolamine-induced learning and memory impairment in rats, the roles of brain-derived neurotrophic factor, nitric oxide and neuroinflammation

The effect of the brain-derived neurotrophic factor (BDNF), cytokines, and renin angiotensin system (RAS) on memory function have been demonstrated. In this study, the effects of RAS inhibitor captopril (Capto) on hippocampal BDNF, interleukin -6 (IL-6), oxidative stress indicators, and nitric oxide (NO) in scopolamine (Sco)-induced memory impairment in rats were examined. The groups were (1) control, (2) Sco in which Sco was applied 30 min prior to the behavioral tests, and (3-5) Sco-Capto 10, 50, and 100 groups, where Capto (10, 50, or 100 mg/kg), were applied 2 weeks prior to the experiment, as well as 30 min prior to each Sco injection. The Morris Water Maze (MWM) test was conducted, and BDNF, IL-6, NO metabolites, malondialdehyde (MDA), thiol, superoxide dismutase (SOD), and catalase (CAT) were measured. Sco increased the delay and distance to the platform in the MWM test (P < .01 to P < .001), while shortening the time and distance in the target area (P < .01 to P < .001). Additionally, Sco increased IL-6, NO metabolites, and MDA, while decreasing BDNF, thiol, SOD, and CAT (P < .01 to P < .001). Although the Capto reduced the latency and distance traveled to the platform (P < .05 to P < .001), it elevated the time and distance traveled in the target area (P < .05 to P < .01). Furthermore, Capto improved BDNF, thiol, SOD, and CAT levels, and decreased IL-6, NO metabolites, and MDA (P < .05 to P < .001). RAS has a role in learning and memory impairment due to cholinergic system dysfunction. The possible mechanism(s) are including its effects on BDNF, neuro-inflammation and oxidative stress.

Conjugated Linoleic Acid-Curcumin Attenuates Cognitive Deficits and Oxidative Stress Parameters in the Ethidium Bromide-Induced Model of Demyelination

Oxidative stress has been shown to play an important role in the pathogenesis of multiple sclerosis (MS). Curcumin (CUR), an antioxidant compound, can be a potent treatment for neurodegenerative diseases, such as MS. CUR has poor bioavailability; therefore, it is used in nanoforms to increase its bioavailability. In the present study, the effects of CUR and conjugated linoleic acid-CUR (Lino-CUR) on spatial memory and oxidative stress in a putative animal model of MS were investigated. Forty-nine adult male Wistar rats (250 ± 50 g) were randomly divided into seven groups (n = 7): control, sham, ethidium bromide (EB), CUR (20 and 40 μg/kg) + EB, and Lino-CUR (20 and 40 μg/kg) + EB groups. Following MS induction, the groups were treated for 5 consecutive days. Finally, spatial memory and levels of oxidative stress parameters were assessed. Treatment with CUR and Lino-CUR at two doses significantly improved spatial memory and reduced oxidative stress parameters in the experimental models of MS. Furthermore, the effects of high dose (40 μg/kg) of Lino-CUR were more remarkable. These findings suggest that the microinjection of CUR in its synthetic form Lino-CUR significantly ameliorated spatial memory, through the reduction of oxidative stress markers in the brain of studied animals as a rat model of MS.

Chemical Profiling and Dose-Dependent Assessment of Fear Reducing and Memory-Enhancing Effects of Solanum virginianum in Rats

The current study was planned to investigate the pharmacological basis of Solanum virginianum extract (SV.CR) pertaining to anxiolytic, antidepressant and memory-enhancing effects in rats. The SV.CR was analyzed in-vitro for phytoconstituents, antioxidant potential and anticholinesterase activity. The rats treated in a dose-dependent manner (25, 50 and 100 mg/kg of SV.CR) were subjected to behavioral tests for anxiety, depression and memory judgment followed by biochemical studies. A notable dose-dependent anxiolytic potential of SV.CR was observed in elevated plus maze and open field tests (P < 0.05). The decreased immobility time of the treated rats in the forced swim test (P < 0.01) unveiled the plant’s potential to reduce depression. Moreover, SV.CR treatment also reversed scopolamine-impaired cognition (P < 0.05) in various deployed memory and learning tasks. Biochemical studies of brain homogenates of SV.CR treated animals demonstrated decreased anticholinesterase activity and lipid peroxidation levels whereas increased levels of superoxide dismutase and glutathione peroxidase (P < 0.05 vs scopolamine group) were noted. The scientific validation of the study supported the use of Solanum virginianum in reducing anxiety, depression and amnesia in experimental models. Phytoconstituents in SV.CR such as oleanolic acid and caffeic acid might have played a significant neuroprotective role via modulation of oxidative stress and neurochemical aspects.

Grewia asiatica Berry Juice Diminishes Anxiety, Depression, and Scopolamine-Induced Learning and Memory Impairment in Behavioral Experimental Animal Models

Grewia asiatica L. fruit natively called phalsa is a popular berry of Pakistan and widely consumed in the form of fresh juices and carbonated drinks in the summer season. The berry is enriched with antioxidants such as phenols, flavonoids, anthocyanins, and vitamin C. Scientifically, it is the least explored berry in terms of neuromodulatory activities, and therefore, in the designed study, chronically fed rats with the different dilutions (5%-30%) of fruit juice were subjected to behavioral assessment for anxiety, depression, and cognition (spatial memory) followed by biochemical analysis of isolated brains. Results revealed a prominent impact of 20 and 30% dilutions of fruit exudate as treated animals showed anxiolytic behavior to central zone (P < 0.05) of open field test (OFT) and open arms of elevated plus maze (EPM) (P < 0.05) in anxiety models. Overall, immobility of rats treated with a higher concentration of exudate in forced swim test (FST) was reduced (P < 0.05) presenting antidepressant-like activity. Moreover, in learning and memory experimental models, the treated animals reversed scopolamine-induced amnesic effects as evident from improved step-through latencies (P < 0.05 vs. scopolamine; passive avoidance test), spontaneous alternation behavior (P < 0.05 vs. scopolamine; Y-maze test), discrimination index (P < 0.05 vs. scopolamine; novel object recognition test), and escape latencies (P < 0.05 vs. scopolamine; Morris water maze). Biochemical studies of isolated brains from treated rats demonstrated significantly elevated levels of superoxide dismutase and glutathione peroxidase (P < 0.05), whereas levels of acetylcholinesterase and malondialdehyde level (P < 0.05) were reduced, indicating its potential to reduce oxidative damage in the brain and modulation with the cholinergic system. The outcomes of studies support the benefits of phytoconstituents possessed by G. asiatica fruit in the amelioration of neurological disorders that could be due to their antioxidative capacity or due to interaction with GABAergic, serotonergic, and cholinergic systems in the brain.

Synergistic effects of quercetin and regular exercise on the recovery of spatial memory and reduction of parameters of oxidative stress in animal model of Alzheimer's disease

It has widely been reported that the brain in Alzheimer's disease (AD) is affected by increased oxidative stress, and this may have a role in the pathogenesis of this disorder. Quercetin, a polyphenol extensively found in nature, has recently been considered. Also, physical activities have a paradoxical effect on brain function in older adults. Therefore, this study aimed at investigating the synergic effects of quercetin (as chemical treatment) and exercise (as physical treatment) on AD-induced learning and memory impairment. Fifty-six adult male Wistar rats were randomly assigned into one of the following eight groups (n=7): The Control, Sham (saline), AD (intracerebroventricular administration of streptozotocin (STZ)), AD+80 mg/kg Quercetin (STZ+Q80), Quercetin vehicle (1 % Ethanol)+STZ, Exercise pretreatment (EX)+STZ, Off the treadmill+STZ, and EX+Q80+STZ. Quercetin administration was done intraperitoneally for 21 days after STZ injection. The rats ran on the treadmill for one hour a day for 60 days at a speed of 20-22 m/min. After the treatment, the spatial memory and levels of oxidative stress parameters were evaluated. The results showed that STZ caused spatial memory impairment and increased oxidative stress in the hippocampus. Exercise pretreatment or Quercetin injection improved the spatial memory impairment and oxidative stress caused by STZ injection. However, the combination of quercetin and exercise pretreatment was more effective. It can be concluded that the combined exercise pretreatment and Quercetin injection affected the antioxidant defense system and improved STZ-induced memory impairment.

Amelioration of Scopolamine-Induced Amnesic, Anxiolytic and Antidepressant Effects of Ficus Benghalensis in Behavioral Experimental Models

Background and Objectives: Ficus benghalensis (FB) is a commonly found tree in Pakistan and its various parts have folkloric importance in managing neurological ailments. In the present study, methanolic extract of its bark has been tested on an experimental animal model to evaluate memory-enhancing, anxiolytic and antidepressant activities to validate the claimed therapeutic potential. Materials and Methods: Methanolic extract of freshly isolated bark was prepared and subjected to preliminary phytochemical studies and gas chromatography-mass spectrometry (GC-MS) analysis for the presence of phytocomponents. To evaluate its effect on spatial learning, passive-avoidance test-step through (PAT-ST), Y-maze and Morris water maze (MWM) tests were carried out. Open-field (OFT) and elevated plus maze (EPM) tests were employed to explore the anti-anxiety potential of FB while a forced swimming test (FST) was utilized to assess its anti-depressant prospective. FB doses of 100, 200 and 300 mg/kg with positive and negative controls given to Sprague Dawley (SD) rats. Results: phytochemical studies showed the presence of various phytoconstituents including alkaloids, flavonoids, terpenes, phenolics and anthraquinones. The presence of synephrine, aspargine, glucose, fructose and fatty acids was revealed by GC-MS analysis. FB administration led to significant improved memory retention when evaluated through passive avoidance (p < 0.05), Y-maze (p < 0.05) and Morris water maze (p < 0.05) tests in a scopolamine model of amnesic rats. When tested by open field and elevated plus maze tests, FB demonstrated anxiety-resolving characteristics (p < 0.05) as animals dared to stay in open areas more than a control group. Mobility time was increased and immobility time was reduced (p < 0.05-0.01) in rats treated with FB, unveiling the anti-depressant importance of F. benghalensis. Conclusion: methanolic extract of F. benghalensis bark furnished scientific proof behind folkloric claims of the memory improving, anxiety-reducing and depression-resolving characteristics of the plant. These activities might be possible due to interaction of its phytoconstituents with serotonergic, glutamatergic, cholinergic and GABAergic systems in the brain.