Cognition Enhancing and Neuromodulatory Propensity of Bacopa monniera Extract Against Scopolamine Induced Cognitive Impairments in Rat Hippocampus

Two new triterpenoid glycosides from Bacopa monnieri and their cytotoxic activity

Using combined chromatographic methods, two new triterpenoid glycosides, bacopasaponin K (1) and bacopasaponin L (2), along with eight known compounds, bacopaside IV (3), bacopaside VII (4), bacopasaponin E (5), bacoside A3 (6), bacopasaponin F (7), bacopasaponin C (8), bacopaside I (9), and bacopaside II (10) were isolated from the methanol extract of the Bacopa monnieri. Their structures were elucidated by 1D-, 2D-NMR spectroscopic analysis, HR-ESI-MS and comparing with the NMR data reported in the literature. All these compounds were evaluated for their cytotoxic activity using the cell counting kit-8 (CCK-8) assay. Compounds 4, 6, 8, and 10 exhibited potential cytotoxic effects against human lung cancer cells (PC9) and human colon cancer cells (SW620).

Memantine versus Ginkgo biloba Extract: A Comparative Study on Cognitive Dysfunction Treatment in a Novel Rat Model

Extracellular senile plaques and intraneuronal neurofibrillary tangles are two devastating brain proteinopathies that are indicative of Alzheimer's disease, the most prevalent type of dementia. Currently, no effective medications are available to stop or reverse Alzheimer's disease. Ginkgo biloba extract, commonly referred to as EGb 761, is a natural product made from the leaves of the G. biloba tree. It has long been demonstrated to have therapeutic benefits in Alzheimer's disease. The current study assessed the beneficial effects of EGb 761 against Alzheimer's disease in comparison with memantine, a standard treatment for Alzheimer's disease. The scopolamine-heavy metals mixture rat Alzheimer's disease model is a newly created model to study the effects of EGb 761 oral therapy on cognitive performance and other Alzheimer's disease-like changes over a 28-day experimental period. This new Alzheimer's disease model provides better criteria for Alzheimer's disease hallmarks than the conventional scopolamine model. The EGb 761 reversed memory and learning deficits induced by the scopolamine-heavy metals mixture. These outcomes were linked to a more pronounced inhibitory effect on acetylcholinesterase, caspase-3, hippocampal amyloid-beta protein (Aβ1 - 42), phosphorylated tau protein counts, and proinflammatory cytokines (tumor necrosis factor-α and interleukin-1β) compared to the memantine-treated group. Furthermore, EGb 761 treatment considerably reduced lipid peroxidation (malondialdehyde) and improved reduced glutathione levels compared to memantine. Our results suggest EGb 761's potential in treating central nervous system disorders. It's a promising candidate for future Alzheimer's disease therapeutic exploration. This study also highlights the need for future research to focus on the positive benefits of herbal medicines.

Vanillin derivatives as antiamnesic agents in scopolamine-induced memory impairment in mice

Amnesia is a major health problem prevalent in almost every part of the world specifically in old age peoples. Vanillin analogues have played an important role in the field medicines. Some of them have been documented to be promising inhibitors of cholinesterases and could therefore, be used as antidepressant, anti-Alzheimer and as neuroprotective drugs. In this connection, the present study was designed to synthesize new vanillin analogues (SB-1 to SB-6) of varied biological potentials. The synthesized compounds were investigated as inhibitors against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes and as scavengers of DPPH and ABTS free radicals followed by behavioural antiamnesic evaluation in mice. The compounds; SB-1, SB-3, SB-4 and SB-6 more potently inhibited AChE with IC50 values of 0.078, 0.157, 0.108, and 0.014 μM respectively. The BChE was more potently inhibited by SB-3 with IC50 of 0.057 μM. Moreover, all of the tested compounds exhibited strong antioxidant potentials with promising results of SB-3 against DPPH with IC50 of 0.305 μM, while SB-5 was most active against ABTS with IC50 of 0.190 μM. The in-vivo studies revealed the improvement in memory deficit caused by scopolamine. Y-Maze and new object recognition test showed a considerable decline in cognitive dysfunctions. In Y-Maze test the spontaneous alteration of 69.44 ± 1% and 84.88 ± 1.35% for SB-1 and 68.92 ± 1% and 80.89 ± 1% for SB-3 at both test doses were recorded while during the novel object recognition test the Discrimination Index percentage of SB-1 was more pronounced as compared to standard drug. All compounds were found to be potent inhibitors of AChE, BChE, DPPH, and ABTS in vitro however, SB-1 and SB-3 were comparatively more potent. SB-1 was also more active in reclamation of memory deficit caused by scopolamine. SB-1 and SB-3 may be considered as excellent drug candidates for treating amnesia subjected to toxicological evaluations in other animal models.

Anti-Alzheimer activity of new coumarin-based derivatives targeting acetylcholinesterase inhibition

New 2-oxo-chromene-7-oxymethylene acetohydrazide derivatives 4a-d were designed and synthesized with a variety of bioactive chemical fragments. The newly synthesized compounds were evaluated as acetylcholinesterase (AChE) inhibitors and antioxidant agents in comparison to donepezil and ascorbic acid, respectively. Compound 4c exhibited a promising inhibitory impact with an IC₅₀ value of 0.802 μM and DPPH scavenging activity of 57.14 ± 2.77%. Furthermore, biochemical and haematological studies revealed that compound 4c had no effect on the blood profile, hepatic enzyme levels (AST, ALT, and ALP), or total urea in 4c-treated rats compared to the controls. Moreover, the histopathological studies of 4c-treated rats revealed the normal architecture of the hepatic lobules and renal parenchyma, as well as no histopathological damage in the examined hepatic, kidney, heart, and brain tissues. In addition, an in vivo study investigated the amelioration in the cognitive function of AD-rats treated with 4c through the T-maze and beam balance behavioural tests. Also, 4c detectably ameliorated MDA and GSH, reaching 90.64 and 27.17%, respectively, in comparison to the standard drug (90.64% and 35.03% for MDA and GSH, respectively). The molecular docking study exhibited a good fitting of compound 4c in the active site of the AChE enzyme and a promising safety profile. Compound 4c exhibited a promising anti-Alzheimer's disease efficiency compared to the standard drug donepezil.

Rosmarinus officinalis and Mentha piperita Oils Supplementation Enhances Memory in a Rat Model of Scopolamine-Induced Alzheimer's Disease-like Condition

Alzheimer's disease is regarded as a common neurodegenerative disease that may lead to dementia and the loss of memory. We report here the nootropic and anti-amnesic effects of both peppermint and rosemary oils using a rat model of scopolamine-induced amnesia-like AD. Rats were administered orally with two doses (50 and 100 mg/kg) of each single oil and combined oils. The positive group used donepezil (1 mg/kg). In the therapeutic phase, rats were administered scopolamine (1 mg/kg) through the oral administration of oils. During the nootropic phase, both oils showed a significant (p < 0.05) decrease in radial arm maze latency times, working memory, and reference memory errors compared with the normal group, along with significant (p < 0.05) enhancements of long-term memory during the passive avoidance test. Therapeutic phase results revealed significant enhancements of memory processing compared with the positive groups. In the hippocampus, oils exhibited an elevation of BDNF levels in a dose-dependent manner. Immunohistochemistry findings showed increased hippocampal neurogenesis suppressed by scopolamine in the sub-granular zone, and the anti-amnesic activity of single oil was enhanced when the two oils combined. Gas chromatography-mass spectrometry (GCMS) of the two oils revealed sufficient compounds (1,8-Cineole, α-Pinene, menthol and menthone) with potential efficacy in the memory process and cognitive defects. Our work suggests that both oils could enhance the performance of working and spatial memory, and when combined, more anti-amnesic activity was produced. A potential enhancement of hippocampal growth and neural plasticity was apparent with possible therapeutic activity to boost memory in AD patients.

Effects of thymoquinone on scopolamine-induced spatial and echoic memory changes through regulation of lipid peroxidation and cholinergic impairment

Thymoquinone (TMQ), one of the main components active of Nigella sativa, shows very useful biomedical properties. Evidence suggests that cholinergic dysfunction and oxidative stress play role in the pathogenesis of neurodegenerative disorders such as Alzheimer's disease (AD). In the present study, we investigated the anti-amnestic effect of TMQ in scopolamine-induced animal model of AD. Wistar rats were randomly divided into four groups; Sham(SH), TMQ-treated(TMQ), scopolamine-treated(SCO) and scopolamine+TMQ-treated(SCO_TMQ) groups. TMQ (20 mg/kg) prepared in corn oil was administered intraperitoneally (i.p.) 1-h before experiments. Scopolamine (1 mg/kg) dissolved in 0.9% physiological saline was administered intraperitoneally (i.p.). We recorded mismatch negativity (MMN) response as an electrophysiological correlate of echoic memory. Object location memory (OLM) and Y-maze alternation tests were carried out to assess spatial memory. Then, the brain homogenates content of thiobarbituric-acid-reactive-substances (TBARS), 4-Hydroxy-2-nonenal (4-HNE) and acetylcholine (ACh)/acetylcholine (AChE) activity were biochemically determined. In the scopolamine-treated rats, TMQ was found to significantly improve the discrimination and spontaneous alteration levels in the OLM and Y-maze tests, respectively. Furthermore, TMQ significantly mitigated the scopolamine-induced attenuation of MMN and related theta responses. Moreover, scopolamine treatment increased TBARS/4-HNE level and decreased ACh level in the brain, and TMQ was able to significantly prevent these effects. AChE activity was increased in the SCO group; this effect was significantly attenuated by TMQ. TMQ diminished the lipid peroxidation and cholinergic dysfunction in the scopolamine-induced AD rat model which all reflected in improving the MMN/theta response and spatial memory. This may implement TMQ as an adjuvant therapeutic strategy in ameliorating AD.

Adaptogenic potential of ginsenosides against domoic acid-induced toxicity by regulating neuronal stress and kinate receptors: Ex vivo and in silico studies

This study is focused on potential effects of ginsenosides from Panax ginseng (PG) against amnesic shell fish poison, that is, domoic acid-induced excitotoxicity. Mice received PG at two different dosages by oral feeding for a period of 28 days (50 and 100 mg kg^-1 bwt.^-1 ). Domoic acid was injected to the mice to induce excitotoxicity (DA; 3 mg kg^-1  bwt.^-1 ) and piracetam-injected animals (PIR; 100 mg kg^-1  bwt.^-1 ) were treated as positive control. DA-induced cognitive impairment was reverted by PG supplementation, which was observed in Morris water maze and novel object task. Moreover, PG supplementation restored levels of GABA and antioxidant enzymes. Our results further elucidated ameliorative effects of PG supplementation on DA-induced changes in the expression of synaptic plasticity (BDNF), inflammation (NFkB), and apoptotic (Bcl2, Bax, and Caspase 3) markers. Hence, this study elucidates potential nootropic effects of ginsenosides from P. ginseng extract against DA-induced neuronal impairments via, modulation of behavioral and biochemical mechanisms involved in excitotoxicity, oxidative stress, neuro-inflammation, and apoptosis. PRACTICAL APPLICATIONS: This study highlights potential effects of ginsenosides from Panax ginseng against amnesic shell fish poison, that is, domoic acid-induced excitotoxicity for the first time. This study confirms that ginsenosides have the beneficial effects against amelioration of DA-induced toxicity. This study elucidates the potential nootropic effects of P. ginseng extract against DA-induced neuronal impairments via, modulation of synaptic plasticity markers and oxido-inflammatory responses leading to apoptosis. This study will be helpful in offering various mechanisms involved in pharmacological applications of P. ginseng in the management of DA-induced excitotoxicity.

An Insight in Pathophysiological Mechanism of Alzheimer's Disease and its Management Using Plant Natural Products

Alzheimer's disease (AD) is an age-associated nervous system disorder and a leading cause of dementia worldwide. Clinically, it is described by cognitive impairment and pathophysiologically by deposition of amyloid plaques and neurofibrillary tangles in the brain and neurodegeneration. This article reviews the pathophysiology, course of neuronal degeneration, and the various possible hypothesis of AD progression. These hypotheses include amyloid cascade, tau hyperphosphorylation, cholinergic disruption, metal dysregulation, vascular dysfunction, oxidative stress, and neuroinflammation. There is an exponential increase in the occurrence of AD in the recent few years that indicate an urgent need to develop some effective treatment. Currently, only 2 classes of drugs are available for AD treatment, namely acetylcholinesterase inhibitor and NMDA receptor antagonist. Since AD is a complex neurological disorder and these drugs use a single target approach, alternatives are needed due to limited effectiveness and unpleasant side-effects of these drugs. Currently, plants have been used for drug development research especially because of their multiple sites of action and fewer side effects. Uses of some herbs and phytoconstituents for the management of neuronal disorders like AD have been documented in this article. Phytochemical screening of these plants shows the presence of many beneficial constituents like flavonoids, triterpenes, alkaloids, sterols, polyphenols, and tannins. These compounds show a wide array of pharmacological activities, such as anti-amyloidogenic, anticholinesterase, and antioxidants. This article summarizes the present understanding of AD progression and gathers biochemical evidence from various works on natural products that can be useful in the management of this disease.

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

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

Dimethyl fumarate abridged tauo-/amyloidopathy in a D-Galactose/ovariectomy-induced Alzheimer's-like disease: Modulation of AMPK/SIRT-1, AKT/CREB/BDNF, AKT/GSK-3β, adiponectin/Adipo1R, and NF-κB/IL-1β/ROS trajectories

Since the role of estrogen in postmenauposal-associated dementia is still debatable, this issue urges the search for other medications. Dimethyl fumarate (DMF) is a drug used for the treatment of multiple sclerosis and has shown a neuroprotective effect against other neurodegenerative diseases. Accordingly, the present study aimed to evaluate the effect of DMF on an experimental model of Alzheimer disease (AD) using D-galactose (D-Gal) administered to ovariectomized (OVX) rats, resembling a postmenopausal dementia paradigm. Adult 18-month old female Wistar rats were allocated into sham-operated and OVX/D-Gal groups that were either left untreated or treated with DMF for 56 days starting three weeks after sham-operation or ovariectomy. DMF succeeded to ameliorate cognitive (learning/short- and long-term memory) deficits and to enhance the dampened overall activity (NOR, Barnes-/Y-maze tests). These behavioral upturns were associated with increased intact neurons (Nissl stain) and a reduction in OVX/D-Gal-mediated hippocampal CA1 neurodegeneration and astrocyte activation assessed as GFAP immunoreactivity. Mechanistically, DMF suppressed the hippocampal contents of AD-surrogate markers; viz., apolipoprotein (APO)-E1, BACE1, Aβ42, and hyperphosphorylated Tau. Additionally, DMF has augmented the neuroprotective parameters p-AKT, its downstream target CREB and BDNF. Besides, it activated AMPK, and enhanced SIRT-1, as well as antioxidant defenses (SOD, GSH). On the other hand, DMF inhibited the transcription factor NF-κB, IL-1β, adiponectin/adiponectin receptor type (AdipoR)1, GSK-3β, and MDA. Accordingly, in this postmenopausal AD model, DMF treatment by pursuing the adiponectin/AdipoR1, AMPK/SIRT-1, AKT/CREB/BDNF, AKT/GSK-3β, and APO-E1 quartet hampered the associated tauo-/amyloidopathy and NF-κB-mediated oxidative/inflammatory responses to advance insights into its anti-amnesic effect.

Galantamine nanoparticles outperform oral galantamine in an Alzheimer's rat model: pharmacokinetics and pharmacodynamics

Aim: Galantamine is an acetylcholinesterase inhibitor frequently used in Alzheimer's disease management. Its cholinergic adverse effects and rapid elimination limit its therapeutic outcomes. We investigated the pharmacodynamics and pharmacokinetics of 2-week intranasal galantamine-bound chitosan nanoparticles (G-NP) treatment in scopolamine-induced Alzheimer's disease rat model. Materials & methods: Behavioral, neurobiochemical and histopathological changes were assessed and compared with oral and nasal solutions. Brain uptake and pharmacokinetics were determined using a novel validated LC/MS assay. Results: G-NP enhanced spatial memory, exploring behavior and cholinergic transmission in rats. Beta-amyloid deposition and Notch signaling were suppressed and the histopathological degeneration was restored. G-NP potentiated galantamine brain delivery and delayed its elimination. Conclusion: G-NP hold promising therapeutic potentials and brain targeting, outperforming conventional galantamine therapy.

Standardized Extract (HemoHIM) Protects against Scopolamine-Induced Amnesia in a Murine Model

HemoHIM is a medicinal herbal preparation of Angelica gigas Nakai (Apiaceae), Cnidium officinale Makino (Umbelliferae), and Paeonia lactiflora Pallas (Paeoniaceae) designed for immune regulation. In the present study, the memory-enhancing effects of a standardized extract (HemoHIM) on scopolamine-induced memory impairment in a murine model was investigated. To induce amnesia, scopolamine (1 mg/kg) was intraperitoneally (i.p.) injected into mice 30 min before the start of behavioral tests. The Y-maze, novel object recognition test (NORT), and passive avoidance task (PAT) were used to evoke memory functions. HemoHIM significantly improved scopolamine-induced memory impairment in ICR mice, which was evidenced by an improvement of spontaneous alternation in the Y-maze, recognition index in NORT, and latency time in PAT. To elucidate the possible mechanism, the cholinergic activity and mRNA levels of choline acetyltransferase (ChAT), muscarinic acetylcholine receptor (mAchR), brain-derived neurotrophic factor (BDNF), and cAMP response element-binding protein (CREB) were measured using reverse transcription (RT-PCR) and western blot analyses, respectively. HemoHIM treatment attenuated the scopolamine-induced hyperactivation of acetylcholinesterase (AchE) activity. In addition, ChAT, mAchR, and CREB mRNA levels were increased in the hippocampus compared with the scopolamine group. Furthermore, HemoHIM treatment resulted in elevated BDNF protein expression. These results indicate that HemoHIM may exert antiamnesic activity by increasing Ach and inhibiting AchE in the hippocampus. In addition, HemoHIM has therapeutic potential by upregulating ChAT, mAchR, and BDNF, which is apparently mediated by activation of the CREB and ERK signaling pathways.

Defensive proclivity of bacoside A and bromelain against oxidative stress and AChE gene expression induced by dichlorvos in the brain of Mus musculus

The objective of current study was to evaluate the neuroprotective effects of bacoside A and bromelain against dichlorvos induced toxicity. The healthy, 6-8 weeks old male Swiss mice were administered in separate groups subacute doses of dichlorvos (40 mg/kg bw), bacoside A (5 mg/kg bw) and bromelain (70 mg/kg bw). In order to determination of oxidative stress in different groups, thiobarbituric acid reactive substances (TBARS) and protein carbonyl content (PCC) were studied in the present investigation. Moreover, for toxic manifestation at molecular level the site-specific gene amplification of acetylcholinesterase (AChE) gene was studied in the brain. Nonetheless, the protective effects of bacoside A and bromelain were also evaluated on the TBARS, PCC and AChE gene. The exposure of dichlorvos leads to significant increase in TBARS level (p < 0.01, p < 0.001) and PCC. Besides, the decline in DNA yield, expression of amplified products of AChE gene was observed in the brain of dichlorvos treated group. The bacoside A and bromelain treatments significantly decreased the level of TBARS (p < 0.05, (p < 0.01) and PCC whereas, increase in the DNA yield and expression of amplified AChE gene products were observed in the brain compared to only dichlorvos treated mice. The overall picture which emerged after critical evaluation of results indicated that the dichlorvos induced oxidative stress and alteration in AChE gene expression showed significant improvement owing to the treatments of bacoside A and bromelain. Thus, bacoside A and bromelain are very effective in alleviating neurotoxicity induced by dichlorvos.

Differential effect of Ayurvedic nootropics on C. elegans models of Parkinson's disease

BACKGROUND

Globally, there is increased incidence of Parkinson's Disease (PD), which is the second most common age-related neurodegenerative disease. The currently available PD-therapeutics provide only symptomatic relief. Thus, there is an urgent need to devise an effective and safe treatment strategy for PD. The holistic approach of Ayurveda can be a potential effective strategy for treating PD. The integration of different medicine systems, such as modern bio-medicine and Ayurveda can be an effective strategy for treatment of complex diseases, including PD.

OBJECTIVE

This study aimed to evaluate the neuroprotective mechanism of six Ayurvedic nootropics that are commonly used to treat PD.

MATERIAL AND METHODS

Six Ayurvedic herbs, namely Mucuna pruriens (MP), Bacopa monnieri (BM), Withania somnifera (WS), Centella asiatica (CA), Sida cordifolia (SC), and Celastrus paniculatus (CP), were selected after consultation with Ayurvedic scholars and physicians. The mode of action of methanolic herbal extracts was evaluated using the Caenorhabditis elegans BZ555 and NL5901 strains, which can be used to model the two main hallmarks of PD, namely degeneration of dopaminergic neurons and aggregation of α-synuclein protein.

RESULTS

All six herbal extracts exhibited neuroprotective effect. The extracts of BM and MP exhibited maximum protection against 1-methyl-4-phenylpyridinium iodide (MPP+ iodide)-induced dopaminergic neurodegeneration in the BZ555 strain. Furthermore, the herbal extracts, except CA extract, inhibited the aggregation of heterologously expressed human α-synuclein in the NL5901 strain.

CONCLUSION

Ayurvedic herbs used in the treatment of PD exhibited differential neuroprotective and protein aggregation mitigating effects in C. elegans.

Effect of Colloidal Aqueous Solution of Fullerene (C60) in the Presence of a P-Glycoprotein Inhibitor (Verapamil) on Spatial Memory and Hippocampal Expression of Sirtuin6, SELADIN1, and AQP1 Genes in a Rat Model of Alzheimer's Disease

Alzheimer's disease (AD) is one of the most common types of neurodegenerative diseases which is accompanied by irreversible neuronal damage, learning difficulties, memory impairments, and cognitive disorders. The cholinergic system is destroyed during AD pathogenesis, leading to the major symptoms of the disease. Although in severe stages AD is life threatening, to date no absolute treatment has been found for this illness and some palliative options are available. The aim of this study was to investigate the effect of fullerene (C60) aqueous suspension (FAS) on improving spatial memory in amnesic male Wistar rats (weighing 200 ± 20 g) and to further compare the results with that of donepezil (DNPZL) as a standard drug. FAS was prepared via a solvent exchange method. The particle size was in the 119.14 ± 3.38 nm range with polydispersity index of 0.15 ± 0.02 and zeta potential of -12.22 ± 5.98 mV. A simple and high sensitive reversed phase high performance liquid chromatography (HPLC) method was developed to identify the C60 concentration in FAS (21 μg/mL). Efficiencies of drugs were examined in both pretreatment and post-treatment groups of animals to better understand how they participate in affecting AD symptoms. Seeing that previous studies have presented antithetical declarations about whether C60 is a P-glycoprotein (P-gp) substrate, we studied FAS effects in both conditions of the presence and absence of a P-gp inhibitor (verapamil HCl, 25 mg/kg). In order to clarify the molecular mechanisms of action of two drugs, their effects on the expression of three principal genes involved in AD, including Sirtuin6, SELADIN1, and AQP1, and as well as their total antioxidant capacities (TACs) were studied. In order to induce memory impairment, scopolamine HBr (SCOP) was administered for 10 days (2 mg/kg/i.p.). FAS and DNPZL administration regimens were 21 μg/mL, BID (i.p.) and 10 mg/kg (p.o.) for 10 days, respectively. Our results introduce FAS as a promising nanoformulation for improving AD symptoms, especially memory impairment, and further assert that more studies are needed to elucidate C60 and P-gp interaction type.

Dammarane triterpenoid glycosides in Bacopa monnieri: A review on chemical diversity and bioactivity

Bacopa monnieri (L.) is a reputed medicinal herb in traditional system of medicine of India, where it is used as nervine tonic to sharpen intellect and memory. This review discusses chemical characterization of dammarane triterpenoid glycosides which are well accepted for improvement in memory and for potential pharmacological activities. In addition, this review provides information on the chemical composition of specialized metabolites of B. monnieri and in the formulations by different analytical techniques. This comprehensive review covers literature up to 2019 with an emphasis on structural characterization of dammarane triterpenoid glycosides by spectroscopic techniques, chemical composition by analytical methods and pharmacological activities.

Ability of Indian pennywort Bacopa monnieri (L.) Pennell in the phytoremediation of sewage (greywater)

The freely and abundantly available amphibious plant Indian pennywort Bacopa monnieri (L.) Pennell was able to phytoremediate sewage (greywater) quickly and substantially in SHEFROL® ("sheet flow root level") bioreactors, achieving reductions in the levels of several indicator parameters: suspended solids, chemical oxygen demand, biological oxygen demand, nitrogen, phosphorus, zinc, copper, nickel, and manganese to the extents of about 90%, 76-77%, 80%, 65%, 55%, 56%, 42%, and 41%, respectively at hydraulic retention times of just 6 h. As these indicators of primary, secondary, and tertiary treatments were achieved simultaneously in a single reactor compartment, the system presented in this paper promises to be simple, rapid, and economical, in achieving significant treatment of greywater.

Embelin Improves the Spatial Memory and Hippocampal Long-Term Potentiation in a Rat Model of Chronic Cerebral Hypoperfusion

Alzheimer's disease (AD) is the second most occurring neurological disorder after stroke and is associated with cerebral hypoperfusion, possibly contributing to cognitive impairment. In the present study, neuroprotective and anti-AD effects of embelin were evaluated in chronic cerebral hypoperfusion (CCH) rat model using permanent bilateral common carotid artery occlusion (BCCAO) method. Rats were administered with embelin at doses of 0.3, 0.6 or 1.2 mg/kg (i.p) on day 14 post-surgery and tested in Morris water maze (MWM) followed by electrophysiological recordings to access cognitive abilities and synaptic plasticity. The hippocampal brain regions were extracted for gene expression and neurotransmitters analysis. Treatment with embelin at the doses of 0.3 and 0.6 mg/kg significantly reversed the spatial memory impairment induced by CCH in rats. Embelin treatment has significantly protected synaptic plasticity impairment as assessed by hippocampal long-term potentiation (LTP) test. The mechanism of this study demonstrated that embelin treatment alleviated the decreased expression of BDNF, CREB1, APP, Mapt, SOD1 and NFκB mRNA levels caused by CCH rats. Furthermore, treatment with embelin demonstrated neuromodulatory activity by its ability to restore hippocampal neurotransmitters. Overall these data suggest that embelin improve memory and synaptic plasticity impairment in CCH rats and can be a potential drug candidate for neurodegenerative disease-related cognitive disorders.

Neuroprotective effects of novel nanosystems simultaneously loaded with vinpocetine and piracetam after intranasal administration

AIMS

The study aim was to test the efficacy of a novel created hybrid nanosystem compared to other nanosystems in treatment of scopolamine induced memory impairment.

MAIN METHODS

The fabrication and characterization of nanoformulations (microemulsion, liposomes, ethosomes, transfersomes and transethosomes) coencapsulating two cognitive enhancers; piracetam and vinpocetine delivered intranasally, in addition to a novel nanocomposite microemulsion/vesicular nanoformulation was described.

KEY FINDINGS

Formulations delivered the drugs across sheep nasal mucosa, with cumulative percentage reaching 29.99% for vinpocetine and 57.78% for piracetam. While the solution form of the drugs was totally ineffective, the selected transethosomal, microemulsion and nanocomposite formulations reversed the scopolamine induced effect on the step through latency of passive avoidance test and the spontaneous alternation behavior in Y maze test, further confirmed by histopathlogical examination. All three nanoformulations significantly decreased the acetylcholinesterase activity and the extent of lipid peroxidation by 32-42%. The nanocomposite formulation was superior to the microemulsion and transethosomal formulations in its anti-inflammatory and antiapoptotic effects, delineated by higher extent of inhibition of COX-2 and caspase 3 expression respectively.

SIGNIFICANCE

Results support the hypothesis that the novel microemulsion/vesicular nanocomposite system is a promising neuroprotective modality for intranasal brain targeting which is worthy of exploitation in other brain diseases.

Lactoferrin-conjugated pH and redox-sensitive polymersomes based on PEG-S-S-PLA-PCL-OH boost delivery of bacosides to the brain

In the present study, engineered lactoferrin (Lf)-conjugated pH and redox-sensitive polymersomes derived from the triblock copolymer polyethylene glycol-S-S-polylactic acid-polycaprolactone (PEG-S-S-PLA-PCL-OH) have been used to deliver bacosides to the brain. Bacosides are classified as triterpenoid saponins and are used in Indian Ayurveda for reversal of amnesia; however, no study has extensively demonstrated their efficacy as a nano-formulation in an animal model. The polymer was synthesized by ring opening polymerization of lactide and ε-caprolactone. The nanoparticles obtained by nanoprecipitation showed a core-shell morphology, with an average size of 110 nm, by transmission electron microscopy (TEM). The colloidal stability, hemocompatibility and cytocompatibility of the polymersomes proved their biocompatibility. pH and disulfide linkages in the polymeric chain accelerated the disintegration of the polymersomes at pH 6.6 and at pH 6.6 with glutathione (GSH) in comparison to pH 7.4, supporting their degradation behavior. Supermagnetic iron oxide nanoparticles (SPIONs, 74.99 μg mg-1 polymer) encapsulated into the polymersomes demonstrated their uptake in a mouse model by MRI. Furthermore, bacosides encapsulated in the polymersomes (10% loading) showed significant memory loss reversal in chemically induced amnesic mice, supported by the gene expression profiles of Arc, BDNF and CREB as well as by histopathology.

Melatonin Improves Cognitive Deficits via Restoration of Cholinergic Dysfunction in a Mouse Model of Scopolamine-Induced Amnesia

Melatonin is known to improve cognitive deficits, and its functions have been studied in various disease models, including Alzheimer's disease. In this study, we investigated effects of melatonin on cognition and the cholinergic system of the septum and hippocampus in a mouse model of scopolamine-induced amnesia. Scopolamine (1 mg/kg) and melatonin (10 mg/kg) were administered intraperitoneally to mice for 2 and 4 weeks. The Morris water maze and passive avoidance tests revealed that both treatments of scopolamine significantly impaired spatial learning and memory; however, 2- and 4-week melatonin treatments significantly improved spatial learning and memory. In addition, scopolamine treatments significantly decreased protein levels and immunoreactivities of choline acetyltransferase (ChAT), high-affinity choline transporter (CHT), vesicular acetylcholine transporter (VAChT), and muscarinic acetylcholine receptor M1 (M1R) in the septum and hippocampus. However, the treatments with melatonin resulted in increased ChAT-, CHT-, VAChT-, and M1R-immunoreactivities and their protein levels in the septum and hippocampus. Our results demonstrate that melatonin treatment is effective in improving the cognitive deficits via restoration of the cholinergic system in the septum and hippocampus of a mouse model of scopolamine-induced amnesia.

Amelioration of Cognitive Deficit by Embelin in a Scopolamine-Induced Alzheimer's Disease-Like Condition in a Rat Model

Embelin (2,5-dihydroxy-3-undecyl-1,4-benzoquinone) is one of the active components (2.3%) found in Embelia ribes Burm fruits. As determined via in vitro AChE inhibition assay, embelin can inhibit the acetylcholinesterase enzyme. Therefore, embelin can be utilized as a therapeutic compound, after further screening has been conducted for its use in the treatment of Alzheimer's disease (AD). In this study, the nootropic and anti-amnesic effects of embelin on scopolamine-induced amnesia in rats were evaluated. Rats were treated once daily with embelin (0.3 mg/kg, 0.6 mg/kg, 1.2 mg/kg) and donepezil (1 mg/kg) intraperitoneally (i.p.) for 17 days. During the final 9 days of treatment, a daily injection of scopolamine (1 mg/kg) was administered to induce cognitive deficits. Besides that, behavioral analysis was carried out to assess the rats' learning and memory functions. Meanwhile, hippocampal tissues were extracted for gene expression, neurotransmitter, and immunocytochemistry studies. Embelin was found to significantly improve the recognition index and memory retention in the novel object recognition (NOR) and elevated plus maze (EPM) tests, respectively. Furthermore, embelin at certain doses (0.3 mg/kg, 0.6 mg/kg, and 1.2 mg/kg) significantly exhibited a memory-enhancing effect in the absence of scopolamine, besides improving the recognition index when challenged with chronic scopolamine treatment. Moreover, in the EPM test, embelin treated rats (0.6 mg/kg) showed an increase in inflection ratio in nootropic activity. However, the increase was not significant in chronic scopolamine model. In addition, embelin contributed toward the elevated expression of BDNF, CREB1, and scavengers enzymes (SOD1 and CAT) mRNA levels. Next, pretreatment of rats with embelin mitigated scopolamine-induced neurochemical and histological changes in a manner comparable to donepezil. These research findings suggest that embelin is a nootropic compound, which also possesses an anti-amnesic ability that is displayed against scopolamine-induced memory impairment in rats. Hence, embelin could be a promising compound to treat AD.

Botanicals as Modulators of Neuroplasticity: Focus on BDNF

The involvement of brain-derived neurotrophic factor (BDNF) in different central nervous system (CNS) diseases suggests that this neurotrophin may represent an interesting and reliable therapeutic target. Accordingly, the search for new compounds, also from natural sources, able to modulate BDNF has been increasingly explored. The present review considers the literature on the effects of botanicals on BDNF. Botanicals considered were Bacopa monnieri (L.) Pennell, Coffea arabica L., Crocus sativus L., Eleutherococcus senticosus Maxim., Camellia sinensis (L.) Kuntze (green tea), Ginkgo biloba L., Hypericum perforatum L., Olea europaea L. (olive oil), Panax ginseng C.A. Meyer, Rhodiola rosea L., Salvia miltiorrhiza Bunge, Vitis vinifera L., Withania somnifera (L.) Dunal, and Perilla frutescens (L.) Britton. The effect of the active principles responsible for the efficacy of the extracts is reviewed and discussed as well. The high number of articles published (more than one hundred manuscripts for 14 botanicals) supports the growing interest in the use of natural products as BDNF modulators. The studies reported strengthen the hypothesis that botanicals may be considered useful modulators of BDNF in CNS diseases, without high side effects. Further clinical studies are mandatory to confirm botanicals as preventive agents or as useful adjuvant to the pharmacological treatment.

Anti-amnesic effects of Ganoderma species: A possible cholinergic and antioxidant mechanism

Mushrooms are valued for their nutritional as well as medicinal properties. Ganoderma species are used traditionally to treat neurological disorders but scientific evidence for this is insufficient. The present study was designed to systematically evaluate the anti-amnesic effect of selected Ganoderma species i.e. G. mediosinense and G. ramosissimum. Extracts of selected mushroom species were evaluated for their antioxidant activity and acetylcholinesterase (AChE) inhibition using in-vitro assays (DPPH and Ellman tests respectively). The anti-amnesic potential of the most active extract (i.e. 70% methanol extract of G. mediosinense) was confirmed using mouse model of scopolamine-induced amnesia. Mice were treated with bioactive extract and donepezil once orally before the induction of amnesia. Cognitive functions were evaluated using passive shock avoidance (PSA) and novel object recognition (NOR) tests. The effect on brain AChE activity, brain oxidative stress (TBARS level) and neuronal damage (H & E staining) were also assessed. In-vitro results showed strong antioxidant and AChE inhibitory activities by G. mediosinense extract (GME). Therefore, it was selected for in-vivo studies. GME pre-treatment (800mg/kg, p.o.) reversed the effect of scopolamine in mice, evident by significant decrease (p <0.05) in the transfer latency time and increase in object recognition index in PSA and NOR, respectively. GME significantly reduced the brain AChE activity and oxidative stress. Histopathological examination of brain tissues showed decrease in vacuolated cytoplasm and increase in pyramidal cells in brain hippocampal and cortical regions. GME exerts anti-amnesic effect through AChE inhibition and antioxidant mechanisms.

Effects of intra-hippocampal microinjection of vitamin B12 on the orofacial pain and memory impairments induced by scopolamine and orofacial pain in rats

In the present study, we investigated the effects of microinjection of vitamin B₁₂ into the hippocampus on the orofacial pain and memory impairments induced by scopolamine and orofacial pain. In ketamine-xylazine anesthetized rats, the right and left sides of the dorsal hippocampus (CA1) were implanted with two guide cannulas. Orofacial pain was induced by subcutaneous injection of formalin (1.5%, 50μl) into the right vibrissa pad, and the durations of face rubbing were recorded at 3-min blocks for 45min. Morris water maze (MWM) was used for evaluation of learning and memory. Finally, locomotor activity was assessed using an open-field test. Vitamin B₁₂ attenuated both phases of formalin-induced orofacial pain. Prior administration of naloxone and naloxonazine, but not naltrindole and nor-binaltorphimine, prevented this effect. Vitamin B₁₂ and physostigmine decreased latency time as well as traveled distance in Morris water maze. In addition, these chemicals improved scopolamine-induced memory impairment. The memory impairment induced by orofacial pain was improved by vitamin B₁₂ and physostigmine used alone. Naloxone prevented, whereas physostigmine enhanced the memory improving effect of vitamin B₁₂ in the pain-induced memory impairment. All the above-mentioned chemicals did not alter locomotor activity. The results of the present study showed that at the level of the dorsal hippocampus, vitamin B₁₂ modulated orofacial pain through a mu-opioid receptor mechanism. In addition, vitamin B₁₂ contributed to hippocampal cholinergic system in processing of memory. Moreover, cholinergic and opioid systems may be involved in improving effect of vitamin B₁₂ on pain-induced memory impairment.

Evaluation of anti-amnesic effect of extracts of selected Ocimum species using in-vitro and in-vivo models

ETHNOPHARMACOLOGICAL RELEVANCE

Ocimum species are traditionally used for the treatment of anxiety, nerve pain, convulsions and a variety of neurodegenerative disorders. The present study was undertaken to evaluate the anti-amnesic effect of O. basilicum L., O. sanctum L. and O. gratissimum L. extracts using in-vitro and in-vivo models.

MATERIALS AND METHODS

In-vitro acetylcholinesterase (AChE) inhibitory and antioxidant activities of hydro-methanol extracts of plants were evaluated using Ellman and DPPH and FRAP assays, respectively. The most active extract i.e. O. basilicum extract (OBE) was further explored for the possible anti-amnesic activity in mouse model of scopolamine induced amnesia using behavioral models (elevated plus maze and passive shock avoidance task). Brain AChE activity, oxidative profile and histopathological studies were assessed to outline the anti-amnesic mechanism of the extract.

RESULTS

Significant antioxidant and AChE inhibition activity was observed with all prepared extracts and however, OBE showed most marked free radical scavenging, reducing power and AChE inhibition (IC₅₀ 0.65±0.15mg/ml) activity. Basil leaves were standardized with respect to content of 7 phenolic acids using a HPLC-PDA method. A TLC densitometric method was employed to determine the quercetin content in the leaves. The in-vivo studies showed that OBE pre-treatment (200 and 400mg/kg, p.o.) reversed the memory deficit induced by scopolamine in mice, evident by significant (p<0.05) decrease in the transfer latency time and increase in step down latency in elevated plus maze and passive shock avoidance task, respectively. Moreover, OBE significantly reduced the brain AChE activity and oxidative stress. Further, histopathological examination of brain tissues displayed decrease in vacuolated cytoplasm and increase in pyramidal cells in hippocampal and cortical regions with OBE pre-treatment.

CONCLUSION

OBE possesses antioxidant and AChE inhibitory activity. These biochemical changes are responsible for the anti-amnesic and neuroprotective activities of O. basilicum which may be attributed to the presence of phenolic and flavonoid compounds. This can be developed as an effective anti-amnesic drug.