Bacopa monniera ameliorates amnesic effects of diazepam qualifying behavioral-molecular partitioning

Bacosides from Bacopa monnieri extract: An overview of the effects on neurological disorders

From ancient history, complementary and alternative medicines have played a significant role as holistic therapeutic treatments of various human diseases including cancer, diabetes, neurological diseases, and skin problems. One Indian medicinal plant (herb), Bacopa monnieri has been used in many parts of the world as such medicine, particularly for the treatment of various neurological disorders. It is well known as a potent "tonic for the human brain," which serves as a memory enhancer. Multiple studies proved that this herb contains a plethora of potential bioactive, phytochemical compounds with synergistic properties. The main purpose of the present review is to shed light on the use of Bacopa monnieri and its active principles (bacosides) in the management of neurological disorders. Furthermore, the signaling pathways modulated by bacosides have been critically discussed in this review. Moreover, we have critically summarized the present knowledge of this perennial creeping herb based upon the literature mining from different scientific engines.

Efficacy of Bacopa Monnieri (Brahmi) and Donepezil in Alzheimer's Disease and Mild Cognitive Impairment: A Randomized Double-Blind Parallel Phase 2b Study

Objectives:

Alzheimer's disease (AD) is the most common cause of dementia worldwide in the older population. There is no disease-modifying therapy available for AD. The current standard of care drug therapy for AD is cholinesterase inhibitors, including donepezil. Bacopa monnieri or brahmi is used in traditional Indian medicine for memory loss. We conducted a phase 2b randomized controlled trial (RCT) to find out the efficacy of brahmi and donepezil in AD and mild cognitive impairment (MCI).

Patients and Methods:

The study was planned as a 52 week, randomized, double-blind, parallel-group, phase-2 single-center clinical trial comparing the efficacy and safety of Bacopa monnieri (brahmi) 300 mg OD and donepezil 10 mg OD for 12 months in 48 patients with AD and MCI-AD including cognitive and quality of life outcomes. The primary outcome was differences in the change from baseline of the neuropsychological tests [Alzheimer's disease assessment scale-cognitive subscale (ADAS-Cog) and postgraduate institute (PGI) memory scale] at 12 months between the intervention group (brahmi) and active comparison group (donepezil).

Results:

The study was terminated after 3 years and 9 months, after recruiting 34 patients, because of slow recruitment and a high dropout rate. Intention to treat analysis after adjusting for baseline confounders showed no difference in the rate of change in ADAS-Cog score from baseline at any time point, including the last follow-up. There was no difference in the rate of change in PGI Memory scale (PGIMS) at 3, 6, and 9 months. In the last follow-up, there was a significant difference in the change in total PGIMS score between brahmi and donepezil, while there was no difference in individual scores of the PGI memory scale.

Conclusion:

This phase-2 RCT on the efficacy of brahmi vs. donepezil showed no significant difference between them after 1 year of treatment. Larger phase-3 trials, preferably multicentric, are required to find the superiority of brahmi over donepezil.

Neuroprotection with Bacopa monnieri-A review of experimental evidence

Brahmi or aindri is a popular herb in the vast and rich compendium of herbs of Ayurveda and is botanically identified as Bacopa monnieri Linn. (BM). It is extensively used in Ayurveda and other traditional systems of medicine in the management of neurological psychiatric disorders. BM possess active principles belonging to alkaloids, glycosides, flavonoids, saponins categories. Numerous research have been undertaken across the globe to evaluate the neuroprotective potential of this herb. This review collates and summarises current (as on May 2020) published literature on Brahmi as a neuroprotective in neurological and psychiatric disorders. English language articles from databases PubMed, Scopus and Google scholar were searched using appropriate free keywords and MeSH terms related to the topic. The review demonstrates the neuroprotective potential of the Ayurveda herb Brahmi in several disorders including Alzheimer's disease, epilepsy, Parkinson's disease, Huntington's disease, cerebral ischemia and infarct and neoplasms.

Neurocognitive Effect of Nootropic Drug Brahmi (Bacopa monnieri) in Alzheimer's Disease

Alzheimer's disease (AD) is a progressive neurodegenerative disease of the elderly. The rapid increase in its incidence has necessitated development of newer drugs. Ayurvedic herbal medications are increasingly researched due to their biosafety profile and usefulness in cognitive impairment. In this article, we critically reviewed one such Medhya Rasayana (nootropic drug) Brahmi-derived from extract of Bacopa monnieri (EBm). Studies have shown that EBm promotes free radical scavenger mechanisms and protects cells in prefrontal cortex, hippocampus, and striatum against cytotoxicity and DNA damage implicated in AD. It also reduces lipoxygenase activity reducing lipid peroxidation, increases glutathione peroxidase and chelates iron. Administration of EBm was seen to protect the cholinergic neurons and reduce anticholinesterase activity comparable to donepezil, rivastigmine, and galantamine. It also reduces hippocampal β-amyloid deposition and stress-induced hippocampal damage. The neuroprotective effect of EBm is also due to nitric oxide-mediated cerebral vasodilation. EBm improved the total memory score and maximum improvement was seen in logical memory and paired associate learning in humans and reversed phenytoin-induced memory impairment in experimental model. EBm has not shown any serious clinical, neurological, hematological complications, or vital organs damage in experimental studies. Rats showed marked reduction in fertility; however, libido was unaffected. There is no experimental evidence of genotoxicity or teratogenesis by use of EBm. Mild nausea and gastrointestinal upset are seen in humans. Brahmi promises to be a novel agent in AD; however, further human trials are recommended to verify the efficacy and rule out any side effects as evidenced by the experimental models.

Translation of Pre-Clinical Studies into Successful Clinical Trials for Alzheimer's Disease: What are the Roadblocks and How Can They Be Overcome?

Preclinical studies are essential for translation to disease treatments and effective use in clinical practice. An undue emphasis on single approaches to Alzheimer's disease (AD) appears to have retarded the pace of translation in the field, and there is much frustration in the public about the lack of an effective treatment. We critically reviewed past literature (1990-2014), analyzed numerous data, and discussed key issues at a consensus conference on Brain Ageing and Dementia to identify and overcome roadblocks in studies intended for translation. We highlight various factors that influence the translation of preclinical research and highlight specific preclinical strategies that have failed to demonstrate efficacy in clinical trials. The field has been hindered by the domination of the amyloid hypothesis in AD pathogenesis while the causative pathways in disease pathology are widely considered to be multifactorial. Understanding the causative events and mechanisms in the pathogenesis are equally important for translation. Greater efforts are necessary to fill in the gaps and overcome a variety of confounds in the generation, study design, testing, and evaluation of animal models and the application to future novel anti-dementia drug trials. A greater variety of potential disease mechanisms must be entertained to enhance progress.

The Molecular Links of Re-Emerging Therapy: A Review of Evidence of Brahmi (Bacopa monniera)

The convolution associated with memory is being resolved with advancement in neuroscience. According to the concurrent assumptions, synaptic plasticity forms one of the basis of memory formation, stabilization and strengthening. In Alzheimer's disease (AD), which is generally characterized by memory dysfunction, connections amongst the cells in the brain are attenuated or lost leading to degeneration of neural networks. Numerous attempts have been made to find new therapies for memory dysfunction with increasing attention and investments being laid on herbal drugs. Many herbal plants and extracts have already documented beneficial results when tested for antiamnesic effects. Brahmi (Bacopa monniera) is one such common herbal drug, which is employed for a long time in the Indian and Chinese medical system in order to treat several disorders. Previous research has shown that Brahmi exerts many pharmacological effects including memory boosting capacity in the treatment of Alzheimer's disease and Schizophrenia, exhibiting antiparkinsonian, antistroke, and anticonvulsant potentials. The present review discusses the chemical constituents of Brahmi along with in vitro and in vivo studies based on the pharmacological effects exerted by it. The efficacy of Brahmi in treating various disorders has evoked sufficient research in recent years and now it is a time to launch multiple clinical trials.

Molecular and Functional Characterization of Bacopa monniera: A Retrospective Review

Over the last 50 years, laboratories around the world analyzed the pharmacological effect of Bacopa monniera extract in different dimensions, especially as a nerve tonic and memory enhancer. Studies in animal model evidenced that Bacopa treatment can attenuate dementia and enhances memory. Further, they demonstrate that Bacopa primarily either acts via antioxidant mechanism (i.e., neuroprotection) or alters different neurotransmitters (serotonin (5-hydroxytryptamine, 5-HT), dopamine (DA), acetylcholine (ACh), γ-aminobutyric acid (GABA)) to execute the pharmacological effect. Among them, 5-HT has been shown to fine tune the neural plasticity, which is a substrate for memory formation. This review focuses on the studies which trace the effect of Bacopa treatment on serotonergic system and 5-HT mediated key molecular changes that are associated with memory formation.

Bacopa monniera selectively attenuates suppressed Superoxide dismutase activity in Diazepam induced amnesic mice

BACKGROUND

Amnesia is characterized by loss of memory that could result from abnormal neuro-chemical homeostasis, genetic predisposition or drug abuse. We earlier reported that B. monniera attenuates diazepam, scopolamine and L-NNA induced amnesia and wanted to test if SOD levels were affected by its administration.

PURPOSE

B. monniera is earlier reported to augment the defense system for oxidative stress by increasing the activities of superoxide dismutase, therefore, we investigated its levels after B. monniera administration in combination with different amnesic agents.

METHODS

We treated mice with amnesic agents such as scopolamine, diazepam, L-NNA and MK 801 either with or without B. monniera.

RESULTS

Diazepam (1.75 mg/kg ip) significantly reduced SOD activity while it was unaltered when Scopolamine (0.1 mg/kg ip), MK 801 (0.17 mg/kg ip) and L-NNA (30 mg/kg ip) were administered. B. monniera significantly attenuated diazepam induced suppression of SOD activity.

CONCLUSION

It is suggested that the mechanism of B. monniera's antiamnesic effect may vary depending on the type of amnesic agent used. However, antioxidant mechanism may be central to evoking the memory enhancing effects of B. monniera against diazepam induced amnesia.

Alterations in brain-derived neurotrophic factor in the mouse hippocampus following acute but not repeated benzodiazepine treatment

Benzodiazepines (BZs) are safe drugs for treating anxiety, sleep, and seizure disorders, but their use also results in unwanted effects including memory impairment, abuse, and dependence. The present study aimed to reveal the molecular mechanisms that may contribute to the effects of BZs in the hippocampus (HIP), an area involved in drug-related plasticity, by investigating the regulation of immediate early genes following BZ administration. Previous studies have demonstrated that both brain derived neurotrophic factor (BDNF) and c-Fos contribute to memory- and abuse-related processes that occur within the HIP, and their expression is altered in response to BZ exposure. In the current study, mice received acute or repeated administration of BZs and HIP tissue was analyzed for alterations in BDNF and c-Fos expression. Although no significant changes in BDNF or c-Fos were observed in response to twice-daily intraperitoneal (i.p.) injections of diazepam (10 mg/kg + 5 mg/kg) or zolpidem (ZP; 2.5 mg/kg + 2.5 mg/kg), acute i.p. administration of both triazolam (0.03 mg/kg) and ZP (1.0 mg/kg) decreased BDNF protein levels within the HIP relative to vehicle, without any effect on c-Fos. ZP specifically reduced exon IV-containing BDNF transcripts with a concomitant increase in the association of methyl-CpG binding protein 2 (MeCP2) with BDNF promoter IV, suggesting that MeCP2 activity at this promoter may represent a ZP-specific mechanism for reducing BDNF expression. ZP also increased the association of phosphorylated cAMP response element binding protein (pCREB) with BDNF promoter I. Future work should examine the interaction between ZP and DNA as the cause for altered gene expression in the HIP, given that BZs can enter the nucleus and intercalate into DNA directly.

Effect of Bacopa monniera extract on methylmercury-induced behavioral and histopathological changes in rats

Methylmercury (MeHg) is a well-recognized environmental contaminant with established health risk to human beings by fish and marine mammal consumption. Bacopa monniera (BM) is a perennial herb and is used as a nerve tonic in Ayurveda, a traditional medicine system in India. This study was aimed to evaluate the effect of B. monniera extract (BME) on MeHg-induced toxicity in rat cerebellum. Male Wistar rats were administered with MeHg orally at a dose of 5 mg/kg b.w. for 21 days. Experimental rats were given MeHg and also administered with BME (40 mg/kg, orally) 1 h prior to the administration of MeHg for 21 days. After treatment period, MeHg exposure significantly decreases the body weight and also caused the following behavioral changes. Decrease tail flick response, longer immobility time, significant decrease in motor activity, and spatial short-term memory. BME pretreatment reverted the behavioral changes to normal. MeHg exposure decreases the DNA and RNA content in cerebellum and also caused some pathological changes in cerebellum. Pretreatment with BME restored all the changes to near normal. These findings suggest that BME has a potent efficacy to alleviate MeHg-induced toxicity in rat cerebellum.

Neuropharmacological review of the nootropic herb Bacopa monnieri

This review synthesizes behavioral research with neuromolecular mechanisms putatively involved with the low-toxicity cognitive enhancing action of Bacopa monnieri (BM), a medicinal Ayurvedic herb. BM is traditionally used for various ailments, but is best known as a neural tonic and memory enhancer. Numerous animal and in vitro studies have been conducted, with many evidencing potential medicinal properties. Several randomized, double-blind, placebo-controlled trials have substantiated BM's nootropic utility in humans. There is also evidence for potential attenuation of dementia, Parkinson's disease, and epilepsy. Current evidence suggests BM acts via the following mechanisms-anti-oxidant neuroprotection (via redox and enzyme induction), acetylcholinesterase inhibition and/or choline acetyltransferase activation, β-amyloid reduction, increased cerebral blood flow, and neurotransmitter modulation (acetylcholine [ACh], 5-hydroxytryptamine [5-HT], dopamine [DA]). BM appears to exhibit low toxicity in model organisms and humans; however, long-term studies of toxicity in humans have yet to be conducted. This review will integrate molecular neuroscience with behavioral research.

An acute, double-blind, placebo-controlled cross-over study of 320 mg and 640 mg doses of Bacopa monnieri (CDRI 08) on multitasking stress reactivity and mood

Little research exists in humans concerning the anxiolytic, antidepressant, sedative, and adaptogenic actions the traditional Ayurvedic medicine Bacopa monnieri (BM) possesses in addition to its documented cognitive-enhancing effects. Preclinical work has identified a number of acute anxiolytic, nootropic, and adaptogenic effects of BM that may also co-occur in humans. The current double-blind, placebo-controlled cross-over study assessed the acute effects of a specific extract of BM (KeenMind® - CDRI 08) in normal healthy participants during completion of a multitasking framework (MTF). Seventeen healthy volunteers completed the MTF, at baseline, then 1 h and 2 h after consuming a placebo, 320 mg BM and 640 mg of BM. Treatments were separated by a 7-day washout with order determined by Latin Square. Outcome measures included cognitive outcomes from the MTF, with mood and salivary cortisol measured before and after each completion of the MTF. Change from baseline scores indicated positive cognitive effects, notably at both 1 h post and 2 h post BM consumption on the Letter Search and Stroop tasks, suggesting an earlier nootropic effect of BM than previously investigated. There were also some positive mood effects and reduction in cortisol levels, pointing to a physiological mechanism for stress reduction associated with BM consumption. It was concluded that acute BM supplementation produced some adaptogenic and nootropic effects that need to be replicated in a larger sample and in isolation from stressful cognitive tests in order to quantify the magnitude of these effects. The study was registered with the Australian and New Zealand Clinical Trials Registry (ACTRN12612000834853).

Effects of NOS inhibitors on the benzodiazepines-induced memory impairment of mice in the modified elevated plus-maze task

The aim of the present study was to examine the effects of nitric oxide synthase (NOS) inhibitors on responses, elicited by benzodiazepines (BZs) in a modified elevated plus-maze task in mice. It was shown that acute doses of diazepam (DZ; 1 and 2 mg/kg) and flunitrazepam (FNZ; 0.05, 0.1 and 0.2 mg/kg) significantly increased the time of transfer latency (TL2) in a retention trial, thus confirming memory impairing effects of BZs. l-NAME (N(G)-nitro-l-arginine methyl ester; 200 mg/kg), a non-selective inhibitor of NOS, and 7-NI (7-nitroindazole; 40 mg/kg), a selective inhibitor of NOS, further intensified DZ-induced memory impairment. On the other hand, L-NAME (50, 100 and 200 mg/kg) and 7-NI (10, 20 and 40 mg/kg) prevented FNZ-induced memory compromising process. The results of this study indicated that suppressed NO synthesis enhanced DZ-induced but prevented FNZ-induced memory impairment. Taken together, these findings could suggest NO involvement in BZs-induced impairment of memory processes. The precise mechanism of these controversial effects, however, remains elusive.

Protective effects of total alkaloidal extract from Murraya koenigii leaves on experimentally induced dementia

Dementia is a syndrome of gradual onset and continuous decline of higher cognitive functioning. It is a common disorder in older persons and has become more prevalent today. The fresh leaves of Murraya koenigii are often added to various dishes in Asian countries due to the delicious taste and flavor that they impart. These leaves have also been proven to have health benefits. In the present study, the effect of total alkaloidal extract from M. koenigii leaves (MKA) on cognitive functions and brain cholinesterase activity in mice were determined. In vitro β-secretase 1 (BACE1) inhibitory activity was also evaluated. The total alkaloidal extract was administered orally in three doses (10, 20 and 30 mg/kg) for 15 days to different groups of young and aged mice. Elevated plus maze and passive avoidance apparatus served as the exteroceptive behavioral models for testing memory. Diazepam-, scopolamine-, and ageing-induced amnesia served as the interoceptive behavioral models. MKA (20 and 30 mg/kg, p.o.) showed significant improvement in memory scores of young and aged mice. Furthermore, the same doses of MKA reversed the amnesia induced by scopolamine (0.4 mg/kg, i.p.) and diazepam (1 mg/kg, i.p.). Interestingly, the brain cholinesterase activity was also reduced significantly by total alkaloidal extract of M. koenigii leaves. The IC50 value of MKA against BACE1 was 1.7 μg/mL. In conclusion, this study indicates MKA to be a useful remedy in the management of Alzheimer's disease and dementia.

Protective role of Ashwagandha leaf extract and its component withanone on scopolamine-induced changes in the brain and brain-derived cells

Background

Scopolamine is a well-known cholinergic antagonist that causes amnesia in human and animal models. Scopolamine-induced amnesia in rodent models has been widely used to understand the molecular, biochemical, behavioral changes, and to delineate therapeutic targets of memory impairment. Although this has been linked to the decrease in central cholinergic neuronal activity following the blockade of muscarinic receptors, the underlying molecular and cellular mechanism(s) particularly the effect on neuroplasticity remains elusive. In the present study, we have investigated (i) the effects of scopolamine on the molecules involved in neuronal and glial plasticity both in vivo and in vitro and (ii) their recovery by alcoholic extract of Ashwagandha leaves (i-Extract).

Methodology/Principal Findings

As a drug model, scopolamine hydrobromide was administered intraperitoneally to mice and its effect on the brain function was determined by molecular analyses. The results showed that the scopolamine caused downregulation of the expression of BDNF and GFAP in dose and time dependent manner, and these effects were markedly attenuated in response to i-Extract treatment. Similar to our observations in animal model system, we found that the scopolamine induced cytotoxicity in IMR32 neuronal and C6 glioma cells. It was associated with downregulation of neuronal cell markers NF-H, MAP2, PSD-95, GAP-43 and glial cell marker GFAP and with upregulation of DNA damage- γH2AX and oxidative stress- ROS markers. Furthermore, these molecules showed recovery when cells were treated with i-Extract or its purified component, withanone.

Conclusion

Our study suggested that besides cholinergic blockade, scopolamine-induced memory loss may be associated with oxidative stress and Ashwagandha i-Extract, and withanone may serve as potential preventive and therapeutic agents for neurodegenerative disorders and hence warrant further molecular analyses.

Effect of soybean supplementation on the memory of alprazolam-induced amnesic mice

Soybean, Glycine max (L.) Merr. (Leguminoseae), is known as golden bean. It contains vegetable protein, oligosaccharide, dietary fiber, vitamins, isoflavones and minerals. Earlier studies have demonstrated a cholesterol lowering, skin protective, antitumour, antidiabetic and antioxidative potential of soybean. Soy isoflavones are also utilized as estrogen replacement therapy in postmenopausal women. The present study was undertaken to investigate the effect of soybean on memory of mice when consumed along with diet. Soybean was administered chronically for 60 consecutive days as three soybean diets viz. Soy2, Soy5, Soy10. These diet contains soybean in normal diet at concentration of 2%, 5%, 10% w/w respectively. Passive avoidance paradigm and elevated plus maze served as exteroceptive behavioral models for testing memory. Alprazolam (0.5 mg/kg; i.p.) induced amnesia served as interoceptive behavioral model. The administration of soybean significantly reversed alprazolam-induced amnesia in a dose-dependent manner as indicated by the increased step down latency of mice using passive avoidance paradigm and increased transfer latency using elevated plus maze. Theses results suggest that consumption of soybean in diet may not only improve memory but also reverse the memory deficits, owing to its multifarious activities. It would be worthwhile to explore the potential of this nutrient in the management of Alzheimer's disease.

Bacopa monniera leaf extract up-regulates tryptophan hydroxylase (TPH2) and serotonin transporter (SERT) expression: implications in memory formation

AIM OF THE STUDY

To examine the effect of Bacopa monniera leaf ethanolic extract (BMEE) on the serotonergic system of postnatal rats with reference to learning and memory.

MATERIALS AND METHODS

From postnatal day (PND)-15-29, rats were treated with BMEE (40 mg/kg BW+0.5% gum acacia) by oral gavage. Behavioural tests (Y-maze, hole-board and passive avoidance) were used to evaluate their learning (PND-32-37) and retention of memory (PND-47-53). Effect of BMEE on neurotransmitter system was analyzed by ELISA and semi-quantitative polymerase chain reaction (PCR).

RESULTS

Oral administration of BMEE improved learning and retention of memory significantly in all behavioural tasks. Following BMEE treatment, the level of serotonin (5-HT) increased while dopamine (DA) decreased significantly. We also found variation in the level of acetylcholine (ACh). However, no significant changes were observed in the level of ACh and glutamate (Glu). The level of 5-HT was significantly elevated up to PND-37 and was then restored to normal level on PND-53. Interestingly, concomitant up-regulation was recorded in the mRNA expression of serotonin synthesizing enzyme tryptophan hydroxylase-2 (TPH2) and serotonin transporter (SERT) on PND-29 and PND-37, which was restored on PND-53.

CONCLUSIONS

The results suggest that BMEE treatment significantly enhances the learning and retention of memory in postnatal rats possibly through regulating the expression of TPH2, 5-HT metabolism and transport.

Bacopa monnieri modulates endogenous cytoplasmic and mitochondrial oxidative markers in prepubertal mice brain

Bacopa monnieri (BM) an herb, found throughout the Indian subcontinent in wet, damp and marshy areas is used in Ayurvedic system of medicine for improving intellect/memory, treatment of anxiety and neuropharmacological disorders. Although extensively given to children as a memory enhancer, no data exists on its ability to modulate neuronal oxidative stress in prepubertal animal models. Hence in this study, we examined if dietary intake of BM leaf powder has the propensity to modulate endogenous markers of oxidative stress, redox status (reduced GSH, thiol status), response of antioxidant defenses (enzymic), protein oxidation and cholinergic function in various brain regions of prepubertal (PP) mice. PP mice maintained on a BM-enriched diet (0.5 and 1%) for 4 weeks showed a significant diminution of basal oxidative markers (malondialdehyde levels, reactive species generation, hydroperoxide levels and protein carbonyls) in both cytoplasm and mitochondria of all brain regions. This was accompanied with enhanced reduced glutathione, thiol levels and elevated activities of antioxidant enzymes (catalase, glutathione peroxidase, superoxide dismutase). Significant reduction in the activity of acetyl cholinesterase enzyme in all brain regions suggested the potential of BM leaf powder to modulate cholinergic function. Further evidence that dietary intake of BM leaf powder confers the prepubertal brain with additional capacity to cope up with neurotoxic prooxidants was obtained by exposing cortical/cerebellar synaptosomes of normal and BM fed mice to 3-nitropropionic acid (3-NPA). While synaptosomes from control mice exhibited a concentration related lipid peroxidation and ROS generation, synaptosomes obtained from BM fed mice showed only a marginal induction at the highest concentration clearly suggesting their increased resistance to 3-NPA-induced oxidative stress. Collectively these data clearly indicate the potential of Bacopa monnieri to modulate endogenous markers of oxidative stress in brain tissue of PP mice. Based on these results, it is hypothesized that dietary intake of BM leaf powder confers neuroprotective advantage and is likely to be effective as a prophylactic/therapeutic agent for neurodegenerative disorders involving oxidative stress.

Loss of learning in mice when exposed to rat odor: a water maze study

The study was designed to test the hypothesis if predator stress can affect learning in mice when exposed to rat odor. We investigated the spatial memory performance of Swiss albino mice in a 7 d Morris water maze (MWM) paradigm by exposing them to the odor of predator (Wistar rats). The results revealed that rat odor produced amnesia in the mice while mice odor did not affect learning in rats, analyzed by the escape latency time (ELT) in acquition trials and search error in retrieval trials. Moreover, the memory loss in mice was comparable to the degree of amnesia produced by scopolamine, a control amnesic agent.

Hyperforin is a modulator of inducible nitric oxide synthase and phagocytosis in microglia and macrophages

Upon activation, microglia, the immunocompetent cells in the brain, get highly phagocytic and release pro-inflammatory mediators like nitric oxide (NO). Excessive NO production is pivotal in neurodegenerative disorders, and there is evidence that abnormalities in NO production and inflammatory responses may at least support a range of neuropsychiatric disorders, including depression. Although extracts of St. John's wort (Hypericum perforatum L.) have been used for centuries in traditional medicine, notably for the treatment of depression, there is still considerable lack in scientific knowledge about the impact on microglia. We used N11 and BV2 mouse microglia, as well as RAW 264.7 macrophages to investigate the effects of St. John's wort extract and constituents thereof on NO production Moreover, flow cytometry and fluorescence microscopy were employed to analyze the influence on phagocytosis, transcription factor activation states, and cell motility. We found that extracts of St. John's wort efficiently suppress lipopolysaccharide-induced NO release and identified hyperforin as the responsible compound, being effective at concentrations between 0.25 and 0.75 microM. The reduced NO production was mediated by diminished inducible nitric oxide synthase expression on the mRNA and protein level. In addition, at similar concentrations, hyperforin reduced zymosan phygocytosis to 20-40% and putatively acted by downregulating the CD206 macrophage mannose receptor and modulation of cell motility. We found that the observed effects correlate with a suppression of the activated state of Nf-kappaB and phospho-CREB, while c-JUN, STAT1, and HIF-1alpha activity and cyclooxygenase-2 expression remained unaffected by hyperforin. These results reveal that hyperforin influences pro-inflammatory and immunological responses of microglia that are involved in the progression of neuropathologic disorders.

Behavioral deficit and decreased GABA receptor functional regulation in the cerebellum of epileptic rats: effect of Bacopa monnieri and bacoside A

In the present study, the effects of Bacopa monnieri and its active component, bacoside A, on motor deficit and alterations of GABA receptor functional regulation in the cerebellum of epileptic rats were investigated. Scatchard analysis of [(3)H]GABA and [(3)H]bicuculline in the cerebellum of epileptic rats revealed a significant decrease in B(max) compared with control. Real-time polymerase chain reaction amplification of GABA(A) receptor subunits-GABA(Aalpha1), GABA(Aalpha5,) and GABA(Adelta)-was downregulated (P<0.001) in the cerebellum of epileptic rats compared with control rats. Epileptic rats exhibit deficits in radial arm and Y-maze performance. Treatment with B. monnieri and bacoside A reversed these changes to near-control levels. Our results suggest that changes in GABAergic activity, motor learning, and memory deficit are induced by the occurrence of repetitive seizures. Treatment with B. monnieri and bacoside A prevents the occurrence of seizures thereby reducing the impairment of GABAergic activity, motor learning, and memory deficit.

Nootropic activity of lipid-based extract of Bacopa monniera Linn. compared with traditional preparation and extracts

Objectives

The aim was to design an alternative solvent-free extraction method using the hydrophilic lipid Gelucire (polyethylene glycol glycerides) for herbal extraction and to confirm the efficacy of extraction using biological screening.

Methods

Bacopa monniera Linn. (BM) was selected for the study. Conventional methanolic extract (MEBM), Ayurvedic ghrita (AGBM) and lipid extracts (LEBM) were prepared and standardised by high-performance thin-layer chromatography (HPTLC). Nootropic activity in rats was evaluated using the two-trial Y-maze test and the anterograde amnesia induced by scopolamine (1 mg/kg i.p.) determined by the conditioned avoidance response. The extracts were administered daily at doses of 100, 200 and 400 mg/kg orally. At the end of the conditioned avoidance response test, brain monoamine levels were estimated by HPLC.

Key findings

The LEBM, MEBM and AGBM contained 3.56%, 4.10% and 0.005% bacoside A, respectively. Significantly greater spatial recognition was observed with LEBM (P &lt; 0.001 at 400 and 200 mg/kg) and MEBM (P &lt; 0.001 at 400 mg/kg, P &lt; 0.01 at 200 mg/kg) than AGBM. The conditioned avoidance response was significantly higher in the groups treated with high doses of LEBM and MEBM than AGBM. There were significant decreases in brain noradrenaline (P &lt; 0.001) and 5-hydroxytryptamine (P &lt; 0.01) levels and an increase in dopamine levels (P &lt; 0.05) in the LEBM-treated groups compared with the stress control group.

Conclusions

The proposed LEBM is solvent free, does not have the shortcomings associated with conventional extraction, and had comparable nootropic activity to the MEBM.