Potential medicinal plants for CNS disorders: an overview

Chinese herbal medicines for the treatment of depression: a systematic review and network meta-analysis

Objectives: Amidst rising global burden of depression and the associated challenges with conventional antidepressant therapies, there is a growing interest in exploring the efficacy and safety of alternative treatments. This study uses a Bayesian network meta-analysis to rigorously evaluate the therapeutic potential of Chinese herbal medicines in the treatment of depression, focusing on their comparative efficacy and safety against standard pharmacological interventions. Methods: Five databases (PubMed, Wanfang Data, EMBASE, CNKI, and the Cochrane Library) and grey literature were searched from inception to end of July 2023 to identify studies that assessed the efficacy and safety of Chinese herbal medicines in treating depression. The response rate, Hamilton Depression Scale (HAMD) scores, and rates of adverse events were assessed through both direct and indirect comparisons. Data extraction and risk of bias assessment were meticulously performed. Statistical analysis used Markov chain Monte Carlo methods, with effect size estimates provided as odd ratios and their 95% confidence intervals. Results: A total of 198 RCTs involving 8,923 patients were analyzed, assessing 17 Chinese herbal medicines. Surface Under the Cumulative Ranking results indicated that the top three treatments with the best response rate were possibly Guipiwan, Ease Pill, and Chaihu Jia Longgu Muli Decoction; the top three treatments on the reduction of HAMD scores were Chai Hu Shu Gan San, Xingnao Jieyu Decoction, and Xiaoyao Powder; and the top three treatments with the lowest adverse effects rates were Xiaoyao Powder, Alprazolam, and Xingnao Jieyu Decoction. Interestingly, commonly used synthetic drugs such as Fluoxetine, Escitalopram, Amitriptyline, Sertraline, Flupentixol and Melitracen, and Venlafaxine, not only appeared to be less effective than specific Chinese herbal medicines (Gan Mai Da Zao Decoction, Chaihu Jia Longgu Muli Decoction, Chai Hu Shu Gan San, Danzhi-Xiaoyao-San, and Xingnao Jieyu Decoction), but they were also related to substantially higher risk of adverse events. Conclusion: Our findings elucidate the promising therapeutic potential of Chinese herbal medicines as viable alternatives in the treatment of depression, with certain herbs demonstrating enhanced efficacy and safety profiles. The outcomes of this study advocate for the integration of these alternative modalities into contemporary depression management paradigms. However, it underscores the necessity for larger, methodologically robust trials to further validate and refine these preliminary findings. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42023452109.

Anti-insomnia Effect of a Polyherbal Formulation on P-chlorophenyalanine Induced Experimental Animal Model

Sleep is a dynamic and controlled set of physiological and behavioural practices during which the stabilisation and restoration processes of the body take place properly. Therefore, sleep disorders, especially chronic insomnia, can harm an individual's physical and mental health. However, the therapeutic alternatives are limited and possess severe side effects. Thus, in this study, we aimed to investigate the anti-insomnia effect of a polyherbal formulation (Sleep) (SLP) on p-chlorophenyalanine (PCPA) induced insomnia in rats. Intraperitoneal injection of PCPA induced the experimental condition, and the therapeutic effect of SLP was evaluated by studying the sleep pattern and expression of various neurotransmitters and receptors, along with neurotrophins. Moreover, insomnia-associated oxidative stress and inflammation were also studied. From the findings, we found that the SLP-supplemented animals improved their sleeping behaviour and that the major neurotransmitters, hormones, and receptors were maintained at an equilibrium level. Furthermore, the neurotrophin level was increased and pro-inflammatory cytokines were reduced. The evaluation of oxidative stress markers shows that the antioxidants were significantly boosted, and as a result, lipid peroxidation was prevented. The overall findings suggest that SLP can be used as an effective medication for the treatment of sleep disorders like insomnia as it triggers the major neurotransmitter system.

Lobeline: A multifunctional alkaloid modulates cholinergic and glutamatergic activities

Developing drugs for Alzheimer's disease (AD) is an extremely challenging task due to its devastating pathology. Previous studies have indicated that natural compounds play a crucial role as lead molecules in the development of drugs. Even though, there are remarkable technological advancements in the isolation and synthesis of natural compounds, the targets for many of them are still unknown. In the present study, lobeline, a piperidine alkaloid has been identified as a cholinesterase inhibitor through chemical similarity assisted target fishing method. The structural similarities between lobeline and donepezil, a known acetylcholinesterase (AChE) inhibitor encouraged us to hypothesize that lobeline may also exhibit AChE inhibitory properties. It was further confirmed by in silico, in vitro and biophysical studies that lobeline could inhibit cholinesterase. The binding profiles indicated that lobeline has a higher affinity for AChE than BChE. Since excitotoxicity is one of the major pathological events associated with AD progression, we also investigated the neuroprotective potential of lobeline against glutamate mediated excitotoxicity in rat primary cortical neurons. The cell based NMDA receptor (NMDAR) assay with lobeline suggested that neuroprotective potential of lobeline is mediated through the blockade of NMDAR activity.

Untangle the mystery behind DS-associated AD - Is APP the main protagonist?

Amyloid precursor protein profusion in Trisomy 21, also called Down Syndrome (DS), is rooted in the genetic determination of Alzheimer's disease (AD). With the recent development in patient care, the life expectancy of DS patients has gradually increased, leading to the high prospect of AD development, consequently leading to the development of plaques of amyloid proteins and neurofibrillary tangles made of tau by the fourth decade of the patient leading to dementia. The altered gene expression resulted in cellular dysfunction due to impairment of autophagy, mitochondrial and lysosomal dysfunction, and copy number variation controlled by the additional genes in Trisomy 21. The cognitive impairment and mechanistic insights underlying DS-AD conditions have been reviewed in this article. Some recent findings regarding biomarkers and therapeutics of DS-AD conditions were highlighted in this review.

Antioxidants: an approach for restricting oxidative stress induced neurodegeneration in Alzheimer's disease

Alzheimer's disease (AD) is the leading cause of dementia, affecting millions of people worldwide. Oxidative stress contributes towards induction of neurodegeneration. It is one of the reasons behind initiation and progression of Alzheimer's disease. Understanding of oxidative balance and restoration of oxidative stress has demonstrated its effectiveness in the management of AD. Various natural and synthetic molecules have been found to be effective in different models of AD. Some clinical studies also support the use of antioxidants for prevention of neurodegeneration in AD. In this review we are summarizing the development of antioxidants to restrict oxidative stress induced neurodegeneration in AD.

Depression and Its Phytopharmacotherapy-A Narrative Review

Depression is a mental health disorder that develops as a result of complex psycho-neuro-immuno-endocrinological disturbances. This disease presents with mood disturbances, persistent sadness, loss of interest and impaired cognition, which causes distress to the patient and significantly affects the ability to function and have a satisfying family, social and professional life. Depression requires comprehensive management, including pharmacological treatment. Because pharmacotherapy of depression is a long-term process associated with the risk of numerous adverse drug effects, much attention is paid to alternative therapy methods, including phytopharmacotherapy, especially in treating mild or moderate depression. Preclinical studies and previous clinical studies confirm the antidepressant activity of active compounds in plants, such as St. John's wort, saffron crocus, lemon balm and lavender, or less known in European ethnopharmacology, roseroot, ginkgo, Korean ginseng, borage, brahmi, mimosa tree and magnolia bark. The active compounds in these plants exert antidepressive effects in similar mechanisms to those found in synthetic antidepressants. The description of phytopharmacodynamics includes inhibiting monoamine reuptake and monoamine oxidase activity and complex, agonistic or antagonistic effects on multiple central nervous system (CNS) receptors. Moreover, it is noteworthy that the anti-inflammatory effect is also important to the antidepressant activity of the plants mentioned above in light of the hypothesis that immunological disorders of the CNS are a significant pathogenetic factor of depression. This narrative review results from a traditional, non-systematic literature review. It briefly discusses the pathophysiology, symptomatology and treatment of depression, with a particular focus on the role of phytopharmacology in its treatment. It provides the mechanisms of action revealed in experimental studies of active ingredients isolated from herbal antidepressants and presents the results of selected clinical studies confirming their antidepressant effectiveness.

Neuroprotective Effects of a Multi-Herbal Extract on Axonal and Synaptic Disruption in Vitro and Cognitive Impairment in Vivo

Background

Alzheimer's disease (AD) is a multifactorial disorder characterized by cognitive decline. Current available therapeutics for AD have limited clinical benefit. Therefore, preventive therapies for interrupting the development of AD are critically needed. Molecules targeting multifunction to interact with various pathlogical components have been considered to improve the therapeutic efficiency of AD. In particular, herbal medicines with multiplicity of actions produce cognitive benefits on AD. Bugu-M is a multi-herbal extract composed of Ganoderma lucidum (Antler form), Nelumbo nucifera Gaertn., Ziziphus jujuba Mill., and Dimocarpus longan, with the ability of its various components to confer resilience to cognitive deficits.

Objective

To evaluate the potential of Bugu-M on amyloid-β (Aβ) toxicity and its in vitro mechanisms and on in vivo cognitive function.

Methods

We illustrated the effect of Bugu-M on Aβ_25-35-evoked toxicity as well as its possible mechanisms to diminish the pathogenesis of AD in rat cortical neurons. For cognitive function studies, 2-month-old female 3×Tg-AD mice were administered 400 mg/kg Bugu-M for 30 days. Behavioral tests were performed to assess the efficacy of Bugu-M on cognitive impairment.

Results

In primary cortical neuronal cultures, Bugu-M mitigated Aβ-evoked toxicity by reducing cytoskeletal aberrations and axonal disruption, restoring presynaptic and postsynaptic protein expression, suppressing mitochondrial damage and apoptotic signaling, and reserving neurogenic and neurotrophic factors. Importantly, 30-day administration of Bugu-M effectively prevented development of cognitive impairment in 3-month-old female 3×Tg-AD mice.

Conclusion

Bugu-M might be beneficial in delaying the progression of AD, and thus warrants consideration for its preventive potential for AD.

Phytochemical screening and effect of Viscum album L. on monoamine oxidase A and B activity and serotonin, dopamine and serotonin receptor 5-HTR1A levels in Galleria mellonealla (Lepidoptera)

ETHNOPHARMACOLOGICAL RELEVANCE

Viscum album L. (European mistletoe), a member of the Santalaceae, is a hemiparasitic, evergreen shrub growing on deciduous and coniferous trees. In traditional and folk medicine, mistletoe was used for the treatment of central nervous system disorders such as epilepsy, hysteria, insomnia, nervous excitability, neuralgia, headache, dizziness and fatigue. However, relatively little is known of its neuropharmacological activity.

AIM OF THE STUDY

The aim of the present study was to evaluate the effect of treatment with aqueous and hydroethanolic extracts from Viscum album L. parasitizing birch, linden and pine, on MAO-A and MAO-B activity as well as serotonin, dopamine and serotonin receptor 5-HTR1A levels in Galleria mellonella (Lepidoptera) larvae.

MATERIALS AND METHODS

The phytochemical composition of the extracts was characterised using UPLC-DAD-ESI-MS/MS. To investigate the neuropharmacological activity of Viscum album L. extracts, Galleria mellonella (Lepidoptera) larvae were used as a model organism. The inhibitory potential of the extracts against MAO-A and MAO-B was determined by fluorometry. The serotonin, dopamine and serotonin receptor 5-HTR1A levels in larvae hemolymph after treatment were quantified by ELISA.

RESULTS

UPLC-DAD-ESI-MS/MS analysis allowed the identification of 88 compounds, either full or in part. Most of the characterised phytochemicals were flavonoids, hydroxycinnamic acids and lignans. Screening found that aqueous and hydroethanolic mistletoe extracts inhibited the enzymatic activity of either MAO-A or MAO-B or both. Additionally, mistletoe extract administration increased the levels of serotonin and serotonin receptor 5-HTR1A. None of the tested extracts had any significant effect on dopamine level.

CONCLUSIONS

A key novel finding was that the aqueous and hydroethanolic extracts from Viscum album L. inhibited monoamine oxidase activity and increased the levels of serotonin and serotonin receptor 5-HTR1A in Galleria mellonella (Lepidoptera) larvae. These properties may be due to the presence of phenolic constituents, particularly flavonoids. Further research based on bioassay-guided fractionation of mistletoe is needed to identify CNS-active molecules.

Protective Mechanisms of Nootropic Herb Shankhpushpi (Convolvulus pluricaulis) against Dementia: Network Pharmacology and Computational Approach

Convolvulus pluricaulis (CP), a Medhya Rasayana (nootropic) herb, is a major ingredient in Ayurvedic and Traditional Chinese formulae indicated for neurological conditions, namely, dementia, anxiety, depression, insanity, and epilepsy. Experimental evidence suggests various neuroactive potentials of CP such as memory-enhancing, neuroprotective, and antiepileptic. However, precise mechanisms underlying the neuropharmacological effects of CP remain unclear. The study, therefore, aimed at deciphering the molecular basis of neuroprotective effects of CP phytochemicals against the pathology of dementia disorders such as Alzheimer's (AD) and Parkinson's (PD) disease. The study exploited bioinformatics tools and resources, such as Cytoscape, DAVID (Database for annotation, visualization, and integrated discovery), NetworkAnalyst, and KEGG (Kyoto Encyclopedia of Genes and Genomes) database to investigate the interaction between CP compounds and molecular targets. An in silico analysis was also employed to screen druglike compounds and validate some selective interactions. ADME (absorption, distribution, metabolism, and excretion) analysis predicted a total of five druglike phytochemicals from CP constituents, namely, scopoletin, 4-hydroxycinnamic acid, kaempferol, quercetin, and ayapanin. In network analysis, these compounds were found to interact with some molecular targets such as prostaglandin G/H synthase 1 and 2 (PTGS1 and PTGS2), endothelial nitric oxide synthase (NOS3), insulin receptor (INSR), heme oxygenase 1 (HMOX1), acetylcholinesterase (ACHE), peroxisome proliferator-activated receptor-gamma (PPARG), and monoamine oxidase A and B (MAOA and MAOB) that are associated with neuronal growth, survival, and activity. Docking simulation further confirmed interaction patterns and binding affinity of selected CP compounds with those molecular targets. Notably, scopoletin showed the highest binding affinity with PTGS1, NOS3, PPARG, ACHE, MAOA, MAOB, and TRKB, quercetin with PTGS2, 4-hydroxycinnamic acid with INSR, and ayapanin with HMOX1. The findings indicate that scopoletin, kaempferol, quercetin, 4-hydroxycinnamic acid, and ayapanin are the main active constituents of CP which might account for its memory enhancement and neuroprotective effects and that target proteins such as PTGS1, PTGS2, NOS3, PPARG, ACHE, MAOA, MAOB, INSR, HMOX1, and TRKB could be druggable targets against dementia.

Emerging Promise of Phytochemicals in Ameliorating Neurological Disorders

BACKGROUND

The field of medicine and synthetic drug development have advanced rapidly over the past few decades. However, research on alternative medicine such as phytochemicals cannot be ignored. The main reason for prominent curiosity about phytochemicals stems from the belief that usage of natural compounds is safer and has lesser detrimental side effects.

OBJECTIVE

The aim of the present review was to discuss in detail with several phytochemicals that have been studied or are being studied in the context of various neurological disorders including depression, Alzheimer's disease, Huntington's disease and even neuroinflammatory disorders such as encephalitis.

METHODS

The potential role of phytochemicals in the treatment or management of symptoms associated with neurological disorders have been included in this article. All data included in this paper has been pooled from various databases including Google Scholar, PubMed, Science Direct, Springer and Wiley Online Library.

RESULTS

Phytochemicals have been widely studied for their therapeutic properties associated with neurological disorders. Using various experimental techniques for both in vivo and in vitro experiments, studies have shown that phytochemicals do have antioxidant, anti-inflammatory and neuroprotective activities which play major roles in the treatment of neurological diseases.

CONCLUSION

Even though there has been compelling evidence of the therapeutic role of phytochemicals, further research is still required to evaluate the safety and efficacy of these medicines. Using previously published papers as foundation for additional research such as preclinical studies and clinical trials, phytochemicals can become a safer alternative to synthetic drugs for treating a spectrum of neurological diseases.

Achyranthes aspera ameliorates stress induced depression in mice by regulating neuroinflammatory cytokines

Background and aim

Achyranthes aspera Linn. (A. aspera) (family: Amaranthaceae) is highly recognized in ethnomedicine and traditional systems of Indian medicine as a nervine restorative for several psychiatric disorders. Study presented here was designed to appraise the antidepressant-like effects of A. aspera in murine model of chronic unpredictable mild stress (CUMS) induced depression.

Experimental procedures-

Rodents were exposed to different stressor in unpredictive manner during CUMS protocol once a day for 4 weeks. Mice were intraperitoneally injected with A. aspera extract (2.5, 5 and 10 mg/kg) or fluoxetine (10 mg/kg) or betaine (20 mg/kg) once daily during day 15–28 of the CUMS protocol. Sucrose preference, motivation and self-care, immobility latency and plasma corticosterone were evaluated after 24 h of last stressor. After behavioral assessments TNF-α, Il-6 and BDNF immunocontent was determined in hippocampus and prefrontal cortex.

Results and conclusion

A. aspera extract as well as betaine improved sucrose preference, increased grooming frequency and latency in splash test and ameliorated depression-like condition in CUMS mice in Porsolt test. A. aspera treatment decreased the elevated plasma corticosterone and reversed the effect of CUMS on TNF-α, Il-6 and BDNF immunocontent in mice. The results of the present study suggest A. aspera as a promising indigenous medicine for stress associated neurobehavioral and comorbid complications.

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Achyranthes aspera is a recognized medicine for psychiatric disorders.

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A. aspera improved sucrose preference, increased grooming frequency and latency in splash test in CUMS mice.

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A. aspera ameliorated depression-like condition in CUMS mice.

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A. aspera treatment decreased the elevated plasma corticosterone and reversed the effect of CUMS on TNF-α, Il-6 and BDNF immunocontent in mice.

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Results suggest A. aspera as a medicine for stress associated neurobehavioral and comorbid complications.

Lipid peroxidation reduction and hippocampal and cortical neurons protection against ischemic damage in animal model using Stellaria media

This study was aimed to determine the neuroprotective influence of Stellaria media in terms of restoring normal state of the rat’s hippocampus and cortex after oxidative insult caused by in vitro ischemia and reperfusion. Cell viability and membrane integrity were assessed using MTT and lactate dehydrogenase (LDH) assay, respectively. Ischemic insult was introduced in the rat brain’s hippocampal and cortical slivers by exposing oxygen and glucose deficiency (OGD) for 2 h, followed by 1 h of re-perfusion. Cellular oxidative stress levels were quantified by incorporating 2ʹ,7ʹ-dichlorofluorescein diacetate fluorescent probes. Additionally, the lipid peroxidation was assessed using TBARS assay. Findings revealed significant neuroprotection against OGD-induced mitochondrial impairment at 40 µg/mL of S. media in rat’s hippocampal and cortical slices. The LDH levels were decreased significantly (P < 0.001) during pre-incubation and reoxygenation periods using varied concentrations of S. media extract. Cellular oxidative stress levels results showed significant (P < 0.001) reduction in dichlorofluorescein fluorescence in slices homogenate of hippocampus and cortex using S. media extract. The lipid peroxidation assay results showed decreased (P < 0.01) levels of malondialdehyde in liver tissues of treated rats treated (200 mg/kg body weight) when compared to the ischemic animal. In summary, findings clearly indicated the neuroprotective effects of extract against in vitro ischemia in brain hippocampal and cortex slivers. S. media could undoubtedly be utilized as a healing agent in preventing neuronal cells’ loss during is chemic-reperfusion process.

Medicinal plants used in traditional Mayan medicine for the treatment of central nervous system disorders: An overview

ETHNOPHARMACOLOGICAL RELEVANCE

For thousands of years, different cultural groups have used and transformed natural resources for medicinal purposes focused on psychological or neurological conditions. Some of these are recognized as central nervous system (CNS) disorders and diseases, whereas other ethnopsychiatric interpretations are explained in culture-specific terms. In traditional Mayan medicine, several herbs have been part of treatments and rituals focused on cultural and ethnomedical concepts.

AIM OF REVIEW

This study aims to provide a comprehensive overview of the medicinal plants used in Mesoamerica by traditional healers and Mayan groups to CNS disorders and associate the traditional use with demonstrated pharmacological evidence to establish a solid foundation for directing future research.

METHODS

A systematic search for primary sources of plant use reports for traditional CNS-related remedies of Mesoamerica were obtained from library catalogs, thesis and scientific databases (PubMed, Scopus, Google Scholar; and Science Direct), and entered in a database with data analyzed in terms of the usage frequency, use by ethnic groups, plant endemism, and pharmacological investigation.

RESULTS

A total of 155 plants used for ethnopsychiatric conditions in Mesoamerica by Mayan groups were found, encompassing 127 native species. Of these, only 49 native species have reported in vitro or in vivo pharmacological analyses. The most commonly reported ethnopsychiatric conditions are related to anxiety, depression, memory loss, epilepsy, and insomnia. The extent of the scientific evidence available to understand the pharmacological application for their use against CNS disorders varied between different plant species, with the most prominent evidence shown by Annona cherimola, Justicia pectoralis, J. spicigera, Mimosa pudica, Persea americana, Petiveria alliacea, Piper amalago, Psidium guajava, Tagetes erecta and T. lucida.

CONCLUSION

Available pharmacological data suggest that different plant species used in traditional Mayan medicine may target the CNS, mainly related to GABA, serotonin, acetylcholine, or neuroprotective pathways. However, more research is required, given the limited data regarding mechanism of action at the preclinical in vivo level, identification of active compounds, scarce number of clinical studies, and the dearth of peer-reviewed studies.

Identification of Potential Human Ryanodine Receptor 1 Agonists and Molecular Mechanisms of Natural Small-Molecule Phenols as Anxiolytics

Natural small-molecule phenols (NSMPs) possess certain ubiquitous bioactivities including the anxiolytic effect. Ryanodine receptor 1 (RyR1) may be one of the potentially critical pharmacological targets for studying the anxiolytic activity of NSMPs. However, detailed molecular mechanisms of NSMPs have not been fully clarified. This research was intended to identify potent hRyR1 agonists from NSMPs and investigate whether RyR1 plays a role in their anxiolytic effect. Homology modeling and molecular docking analysis were performed using Accelrys Discovery Studio 2.5. The most appropriate concentrations of NSMPs to activate RyR1 were measured using the MTT assay. Fluorescence analyses of the intracellular calcium levels and western blotting analysis were carried out to validate whether NSMPs could regulate the calcium flux to some extent by activating RyR1. The results demonstrated that xanthotoxol and 5-hydroxy-1,4-naphthalenedione can be screened as hit compounds for potential agonists of hRyR1 to exert the anxiolytic effect. In conclusion, NSMPs might be a kind of pharmacological signal carrier, acting on RyR1 as an agonist and resulting in calcium ion mobilization from intracellular calcium ion store.

Neuroregenerative Potential of Prenyl- and Pyranochalcones: A Structure-Activity Study

Loss of neuronal tissue is a hallmark of age-related neurodegenerative diseases. Since adult neurogenesis has been confirmed in the human brain, great interest has arisen in substances stimulating the endogenous neuronal regeneration mechanism based on adult neural stem cells. Medicinal plants are a valuable source of neuroactive small molecules. In the structure-activity study presented here, the activities of prenyl- and pyranochalcones were compared to each other, using a differentiation assay based on the doublecortin promoter sequences. The latter revealed that the pyrano ring is a crucial structural element for the induction of neuronal differentiation of adult neural stem cells, while compounds with a prenyl group show significantly lower activities. Furthermore, a decrease of pro-differentiation activity was observed following structural modifications, such as substitutions on the pyrano ring and on the B-ring of the chalcone. We also initiated the elucidation of the structural characteristics of the newly discovered lead substance xanthohumol C, which correlated with the activation of the doublecortin promoter during neuronal differentiation.

Ethnomedicine and neuropsychopharmacology in Mesoamerica

ETHNOPHARMACOLOGICAL RELEVANCE

The burden of disease caused by mental and neurological disorders is increasing globally, to a disproportionate degree in Latin America. In contrast to the many psychoactive plants with a use history in Mesoamerican cultures, the translation to the wider population of knowledge around numerous botanicals used contemporarily by indigenous Mesoamerican societies to treat psychological and neurological disorders did not receive the same attention.

MATERIAL AND METHODS

We used the previously published Mesoamerican Medicinal Plant Database to extract species and associated botanical drugs used as treatments for illnesses associated with the nervous system by Mesoamerican cultures in Belize, Guatemala, and Mexico. With the critical use of published pharmacological literature, the cross-culturally most salient genera are systematically reviewed.

RESULTS

From 2188 plant taxa contained in the database 1324 are used as treatments for illnesses associated with the nervous system. The ethnomedical data was critically confronted with the available biomedical literature for the 58 cross-culturally most salient genera. For a considerable proportion of the frequently used taxa, preclinical data are available, mostly validating ethnomedicinal uses.

CONCLUSION

This quantitative approach facilitates the prioritization of taxa for future pre-clinical, clinical and treatment outcome studies and gives patients, practitioners, and legislators a fundamental framework of evidence, on which to base decisions regarding phytomedicines.

The clinical use of curcumin on neurological disorders: An updated systematic review of clinical trials

Neuroprotective effects of curcumin have been shown in previous studies. This updated systematic review of clinical trials aimed to investigate the effect of curcumin on neurological disorders. Databases including PubMed, Scopus, Web of Science, and Google Scholar were systematically searched to identify clinical trials investigating the effects of curcumin/turmeric supplements alone, or in combination with other ingredients, on neurological diseases. Nineteen studies comprising 1,130 patients met the inclusion criteria. Generally, intervention and study outcomes were heterogeneous. In most of the studies, curcumin had a favorable effect on oxidative stress and inflammation. However, with the exception of AD, curcumin supplementation either alone, or in combination with other ingredients, had beneficial effects on clinical outcomes for the other aforementioned neurodegenerative diseases. For example, the frequency, severity, and duration of migraine attacks, scores on the revised ALS functional rating scale, and the occurrence of motor complications in PD were all significantly improved with curcumin supplementation either alone or in combination with other ingredients. However, in three studies, several adverse side effects (mostly gastrointestinal in nature) were reported. Curcumin supplementation may have favorable effects on inflammatory status and clinical outcomes of patients with neurological disease, although the results were not consistent.

Mechanism of action involved in the anxiolytic-like effects of Hibalactone isolated from Hydrocotyle umbellata L

Background and aim

Hibalactone (HB) is a lignan related to the anxiolytic-like effects of Hydrocotyle umbellata L. However, there is a need to understand better the mechanism of action of this lignan to support the ethnopharmacological uses of the species. This work aimed to evaluate by in vivo and in silico analysis the mechanism of action of HB involved in its anxiolytic-like effects.

Experimental procedure

The effects of HB in mice were evaluated on light-dark box (LDB) and elevated plus maze (EPM) tests. The participation of 5-HT_1A receptor and the benzodiazepine site of GABA_A receptor was evaluated to investigate the possible mechanism of action. In silico tools were used to better elucidate the anxiolytic-like effects of HB.

Results

Oral treatment with HB at a dose of 33 mg/kg showed an anxiolytic-like effect in the LDB and EPM tests. Besides that, the treatment altered the ethological parameters, frequency of head dips, and stretched-attend postures (SAP), important to better describe the anxiolytic profile of HB. Pretreatment with flumazenil (2 mg/kg) reverted the anxiolytic-like effect of HB on LDB and EPM tests. On the other hand, pretreatment with NAN-190 (0.5 mg/kg) not reverted the activity observed. In silico predictions revealed the potential of HB to increase GABAergic neurotransmission. Pharmacophore modelling and docking simulations showed that HB might interact with the α1β2γ2 GABA_A receptor.

Conclusion

Together, the results presented herein suggest that activation of the benzodiazepine site of the GABA_A receptor contributes to the anxiolytic-like effect of HB.

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Pretreatment with flumazenil reverted the anxiolytic-like effect of hibalactone.

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Pretreatment with NAN-190 not reverted the activity observed.

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In silico findings showed that hibalactone may interact with α1β2γ2 GABA_A receptor.

A Novel Cardenolide Glycoside Isolated from Xysmalobium undulatum Reduces Levels of the Alzheimer's Disease-Associated β-Amyloid Peptides Aβ42 In Vitro

Elevated levels of the amylo β-proteins (Aβ), particularly Aβ42, are associated with a high risk of Alzheimer’s disease (AD). The Aβ proteins are produced from cellular processing of the amyloid precursor proteins (APPs). To identify natural products that block the formation of Aβ-proteins from APPs, we previously screened a library of plant extracts and identified Xysmalobium undulaum (Apocynaceae) as a potential plant for further research. Here, we provide a report on the isolation and identification of the active principles from the plant species using a bioassay-guided fractionation. Fractions and resulting pure compounds from the purification process of the extract of X. undulatum were screened in vitro against APPs transfected HeLa cell lines. Three compounds, acetylated glycosydated crotoxogenin (1), xysmalogenin-3, β-d-glucopyranoside (2), and crotoxigenin 3-O-glucopyranoside (3), were subsequently isolated and their structures elucidated using NMR and mass spectrometry. Compound 1, a novel cardenolide, and 2 significantly decreased the Aβ42 levels in a dose-dependent manner while compound 3 was inactive. In silico investigations identified the AD’s β-secretase enzyme, BACE1, as a potential target for these compounds with the glycoside moiety being of significance in binding to the enzyme active site. Our study provides the first report of a novel cardenolide and the potential of cardenolides as chemical scaffolds for developing AD treatment drugs.

The Anticonvulsant Effect of Hydroethanolic Leaf Extract of Calotropis procera (Ait) R. Br. (Apocynaceae)

A number of currently used drugs have been obtained from medicinal plants which are a major source of drugs. These drugs are either used in their pure form or modified to a semisynthetic drug. Drug discovery through natural product research has been fruitful over the years. Traditionally, Calotropis procera is used extensively in the management of epilepsy. This study is conducted to explore the anticonvulsant effect of a hydroethanolic leaf extract of Calotropis procera (CPE) in murine models. This effect was evaluated using picrotoxin-induced convulsions, strychnine-induced convulsions, and isoniazid- and pilocarpine-induced status epilepticus in mice of both sexes. The results showed that CPE (100-300 mg/kg) exhibited an anticonvulsant effect against strychnine-induced clonic seizures by significantly reducing the duration (p = 0.0068) and frequency (p = 0.0016) of convulsions. The extract (100-300 mg/kg) caused a profound dose-dependent delay in the onset of clonic convulsions induced by picrotoxin (p < 0.0001) and tonic convulsions (p < 0.0001) in mice. The duration of convulsions was reduced significantly also for both clonic and tonic (p < 0.0001) seizures as well. CPE (100-300 mg/kg), showed a profound anticonvulsant effect and reduced mortality in the pilocarpine-induced convulsions. ED₅₀ (~0.1007) determined demonstrated that the extract was less potent than diazepam in reducing the duration and onset of convulsions but had comparable efficacies. Flumazenil—a GABA_A receptor antagonist—did not reverse the onset or duration of convulsions produced by the extract in the picrotoxin-induced seizure model. In isoniazid-induced seizure, CPE (300 mg kg¹, p.o.) significantly (p < 0.001) delayed the onset of seizure in mice and prolonged latency to death in animals. Overall, the hydroethanolic leaf extract of Calotropis procera possesses anticonvulsant properties.

Movement of prion-like α-synuclein along the gut-brain axis in Parkinson's disease: A potential target of curcumin treatment

A pathological hallmark of the neurodegenerative disorder, Parkinson's disease (PD), is aggregation of toxic forms of the presynaptic protein, α-synuclein in structures known as Lewy bodies. α-Synuclein pathology is found in both the brain and gastrointestinal tracts of affected individuals, possibly due to the movement of this protein along the vagus nerve that connects the brain to the gut. In this review, we discuss current insights into the spread of α-synuclein pathology along the gut-brain axis, which could be targeted for therapeutic interventions. The prion-like propagation of α-synuclein, and the clinical manifestations of gastrointestinal dysfunction in individuals living with PD, are discussed. There is currently insufficient evidence that surgical alteration of the vagus nerve, or removal of gut-associated lymphoid tissues, such as the appendix and tonsils, are protective against PD. Furthermore, we propose curcumin as a potential candidate to prevent the spread of α-synuclein pathology in the body by curcumin binding to α-synuclein's non-amyloid β-component (NAC) domain. Curcumin is an active component of the food spice turmeric and is known for its antioxidant, anti-inflammatory, and potentially neuroprotective properties. We hypothesize that once α-synuclein is bound to curcumin, both molecules are subsequently excreted from the body. Therefore, dietary supplementation with curcumin over one's lifetime has potential as a novel approach to complement existing PD treatment and/or prevention strategies. Future studies are required to validate this hypothesis, but if successful, this could represent a significant step towards improved nutrient-based therapeutic interventions and preventative strategies for this debilitating and currently incurable disorder.

Therapeutic Potential of Phytoconstituents in Management of Alzheimer's Disease

Since primitive times, herbs have been extensively used in conventional remedies for boosting cognitive impairment and age-associated memory loss. It is mentioned that medicinal plants have a variety of dynamic components, and they have become a prominent choice for synthetic medications for the care of cognitive and associated disorders. Herbal remedies have played a major role in the progression of medicine, and many advanced drugs have already been developed. Many studies have endorsed practicing herbal remedies with phytoconstituents, for healing Alzheimer's disease (AD). All the information in this article was collated from selected research papers from online scientific databases, such as PubMed, Web of Science, and Scopus. The aim of this article is to convey the potential of herbal remedies for the prospect management of Alzheimer's and related diseases. Herbal remedies may be useful in the discovery and advancement of drugs, thus extending new leads for neurodegenerative diseases such as AD. Nanocarriers play a significant role in delivering herbal medicaments to a specific target. Therefore, many drugs have been described for the management of age-linked complaints such as dementia, AD, and the like. Several phytochemicals are capable of managing AD, but their therapeutic claims are restricted due to their lower solubility and metabolism. These limitations of natural therapeutics can be overcome by using a targeted nanocarrier system. This article will provide the primitive remedies as well as the development of herbal remedies for AD management.

Neuroprotective Natural Products for Alzheimer's Disease

Alzheimer's disease (AD) is the number one neurovegetative disease, but its treatment options are relatively few and ineffective. In efforts to discover new strategies for AD therapy, natural products have aroused interest in the research community and in the pharmaceutical industry for their neuroprotective activity, targeting different pathological mechanisms associated with AD. A wide variety of natural products from different origins have been evaluated preclinically and clinically for their neuroprotective mechanisms in preventing and attenuating the multifactorial pathologies of AD. This review mainly focuses on the possible neuroprotective mechanisms from natural products that may be beneficial in AD treatment and the natural product mixtures or extracts from different sources that have demonstrated neuroprotective activity in preclinical and/or clinical studies. It is believed that natural product mixtures or extracts containing multiple bioactive compounds that can work additively or synergistically to exhibit multiple neuroprotective mechanisms might be an effective approach in AD drug discovery.

Tanshinone IIA: A phytochemical as a promising drug candidate for neurodegenerative diseases

Tanshinones, lipophilic diterpenes isolated from the rhizome of Salvia miltiorrhiza, have diverse pharmacological activities against human ailments including neurological diseases. In fact, tanshinones have been used to treat heart diseases, stroke, and vascular diseases in traditional Chinese medicine. During the last decade, tanshinones have been the most widely studied phytochemicals for their neuroprotective effects against experimental models of cerebral ischemia and Alzheimer's diseases. Importantly, tanshinone IIA, mostly studied tanshinone for biological activities, is recently reported to attenuate blood-brain barrier permeability among stroke patients, suggesting tanshinone IIA as an appealing therapeutic candidate for neurological diseases. Tanshinone I and IIA are also effective in experimental models of Parkinson's disease, Multiple sclerosis, and other neuroinflammatory diseases. In addition, several experimental studies suggested the pleiotropic neuroprotective effects of tanshinones such as anti-inflammatory, antioxidant, anti-apoptotic, and BBB protectant further value aiding to tanshinone as an appealing therapeutic strategy in neurological diseases. Therefore, in this review, we aimed to compile the recent updates and cellular and molecular mechanisms of neuroprotection of tanshinone IIA in diverse neurological diseases.

Neuroprotective Herbs for the Management of Alzheimer's Disease

Background—Alzheimer’s disease (AD) is a multifactorial, progressive, neurodegenerative disease that is characterized by memory loss, personality changes, and a decline in cognitive function. While the exact cause of AD is still unclear, recent studies point to lifestyle, diet, environmental, and genetic factors as contributors to disease progression. The pharmaceutical approaches developed to date do not alter disease progression. More than two hundred promising drug candidates have failed clinical trials in the past decade, suggesting that the disease and its causes may be highly complex. Medicinal plants and herbal remedies are now gaining more interest as complementary and alternative interventions and are a valuable source for developing drug candidates for AD. Indeed, several scientific studies have described the use of various medicinal plants and their principal phytochemicals for the treatment of AD. This article reviews a subset of herbs for their anti-inflammatory, antioxidant, and cognitive-enhancing effects. Methods—This article systematically reviews recent studies that have investigated the role of neuroprotective herbs and their bioactive compounds for dementia associated with Alzheimer’s disease and pre-Alzheimer’s disease. PubMed Central, Scopus, and Google Scholar databases of articles were collected, and abstracts were reviewed for relevance to the subject matter. Conclusions—Medicinal plants have great potential as part of an overall program in the prevention and treatment of cognitive decline associated with AD. It is hoped that these medicinal plants can be used in drug discovery programs for identifying safe and efficacious small molecules for AD.

Potential roles of natural products in the targeting of proteinopathic neurodegenerative diseases

Defective proteostasis is associated with the gradual accumulations of misfolded proteins and is a hallmark of many age-associated neurodegenerative diseases. In the aged brain, maintenance of the proteostasis network presents a substantial challenge, and its loss contributes to the onset and progression of neurological diseases associated with cognitive decline due to the generation of toxic protein aggregates, a process termed 'proteinopathy'. Emerging evidence suggests that reversing proteinopathies by boosting proteostasis might provide an effective means of preventing neurodegeneration. From this perspective, phytochemicals may play significant roles as potent modulators of the proteostasis network, as previous reports have suggested they can interact with various network components to modify pathologies and confer neuroprotection. This review focuses on some potent phytochemicals that directly or indirectly modulate the proteostasis network and on their possible molecular targets. In addition, we propose strategies for the natural product-based modulation of proteostasis machinery that target proteinopathies.

Neuro-nutraceutical potential of Asparagus racemosus: A review

Debilitating neuropsychiatric and neurodegenerative conditions are associated with complex multifactorial pathophysiology. Their treatment strategies often only provide symptomatic relief, delaying disease progression without giving a complete cure. Potent and safer treatment alternatives beyond symptomatic relief are sought. Herbal supplements have surely been explored due to their multiple component nature to enhance the effect of western medications. One such well-documented nutraceutical in the ancient Greek, Chinese, and Ayurvedic medicine system known for its various medicinal benefits is Asparagus racemosus. Widely used for its lactogenic properties, A. racemosus is also cited in Ayurveda as a nervine tonic. A. racemosus based nutraceuticals have shown to possess adaptogenic, neuroprotective, antioxidant, anti-inflammatory, and nootropic activity under preclinical and clinical settings without posing significant adverse effects. A. racemosus extracts restore the perturbed neurotransmitters and prevent oxidative neuronal damage. From the available neuropharmacological researches, the physiological actions of A. racemosus can ultimately be directed for either augmentation of cognitive ability or in the management of neurological conditions such as stress, anxiety, depression, epilepsy, Parkinson's, and Alzheimer's disease. The studies focus on the multi-component extract, and the lack of standardization has been a major hurdle in preventing the allotment of reported neuropharmacological activity to one of the phytoconstituent. Herbal standardization of the plant extract based on a specific biomarker can help elucidate the intricate biomolecular pathway and neurocircuitries being involved. This, followed by rigorous standardized clinical trials, fixing dosages, and determining contraindications would facilitate the translation of A. racemosus to a FDA-approved neuromedicine for neurological disorders.

Anti-anxiety properties of selected medicinal plants

Exploration of new drugs targeting anxiety treatment is a major concern worldwide. Medicinal plants are being used as a potential source of novel drugs for anxiety disorders. The objective of this review is to provide information about the healing outcomes of anxiety treatment with natural products. Valeriana officinalis, Citrus aurantium, Commelina benghalensis, Achyranthes aspera, Mimosa pudica, Achillea millefolium, Nymphaea alba, Leonurus cardiac, Camellia sinensis, Turnera aphrodisiaca, Crataegus oxyacantha and Piper methysticum showed promising effects on anxiety in animal models. In clinical studies, passion flower, kava, valerian, St John's wort, and ashwagandha showed the most positive results. More studies are needed for the exploration of the anti-anxiety of medicinal plants. In drugs derived from natural sources have explored many components that are playing an essential role in curing anxiety disorders and associated complications.

Pyridine alkaloids with activity in the central nervous system

This review discusses all pyridine alkaloids with CNS activity, their therapeutic potential, and the interesting array of sources whence they originate.

Traditional Herbal Medicines Against CNS Disorders from Bangladesh

The majority of the population in Bangladesh uses traditional plant-based medicines to manage various ailments, including central nervous system (CNS) disorders. This review presents ethnobotanical information and relevant scientific studies on plants used in traditional healthcare for the management of various CNS disorders in Bangladesh. The information on the medicinal plants of Bangladesh effective against CNS disorders published in scientific journals, books, and reports was compiled from different electronic databases using specific key words. The present article provides comprehensive information on a total of 224 medicinal plant species belonging to 81 families used for the treatment of CNS disorders by the various peoples of Bangladesh. In total, we reviewed more than 290 relevant papers. In this study, leaves were found as the most often used plant organ, followed by roots, fruits, whole plants, barks, seeds, stems, rhizomes, and flowers. The Fabaceae family contributes the highest number of used species, followed by Rubiaceae, Lamiaceae, Cucurbitaceae, Vitaceae, Euphorbiaceae, Malvaceae, and Zingiberaceae. The most frequently used species (in decreasing order) are Asparagus racemosus, Centella asiatica, Stephania japonica, Aegle marmelos, Coccinia grandis, Tabernaemontana divaricata, Bacopa monnieri, Abroma augusta, and Scoparia dulcis. This review may serve as a starting point for a rational search for neuroactive natural products against CNS disorders within the Flora of Bangladesh.

Pathophysiology of Depression and Novel Sources of Phytochemicals for its Treatment – A Systematic Review

The rising burden of depression, which will soon be the second most common cause of disability in the world, is requesting new ways to treat and prevent it. Due to high number of significant adverse drug reactions of the conventional treatment, the modern pharmaceutical industry is more often turning their focus to novel plant-based solutions. We performed literature research based on standard literature search engines – PubMed, Google Scholar, Science Direct. A standard set of keywords related to our topic e.g. “Depression”, “Mesembrine type alkaloids”, “Narcissus” was used. The review describes the classical monoamine theory of depression and connects it with the newly found biochemical, genetic and morphological alterations associated with the major depressive disorder. The purpose of this review is to highlight the most important aspects of the pathophysiology of depression and to explore the possibilities to use mesembrine-like alkaloids isolated from Narcissus cv. Hawera in its treatment. We describe their effect on brain biochemistry and possible future investigations.

Identification of Molecular Network Associated with Neuroprotective Effects of Yashtimadhu (Glycyrrhiza glabra L.) by Quantitative Proteomics of Rotenone-Induced Parkinson's Disease Model

Parkinson's disease (PD) is a progressive neurodegenerative disorder, whose treatment with modern therapeutics leads to a plethora of side effects with prolonged usage. Therefore, the management of PD with complementary and alternative medicine is often pursued. In the Ayurveda system of alternative medicine, Yashtimadhu choorna, a Medhya Rasayana (nootropic), prepared from the dried roots of Glycyrrhiza glabra L. (licorice), is prescribed for the management of PD with a favorable outcome. We pursued to understand the neuroprotective effects of Yashtimadhu choorna against a rotenone-induced cellular model of PD using differentiated IMR-32 cells. Cotreatment with Yashtimadhu choorna extract rescued rotenone-induced apoptosis and hyperphosphorylation of ERK-1/2. Quantitative proteomic analysis of six peptide fractions from independent biological replicates acquired 1,561,169 mass spectra, which when searched resulted in 565,008 peptide-spectrum matches mapping to 30,554 unique peptides that belonged to 4864 human proteins. Proteins commonly identified in biological replicates and >4 PSMs were considered for further analysis, leading to a refined set of 3720 proteins. Rotenone treatment differentially altered 144 proteins (fold ≥1.25 or ≤0.8), involved in mitochondrial, endoplasmic reticulum, and autophagy functions. Cotreatment with Yashtimadhu choorna extract rescued 84 proteins from the effect of rotenone and an additional regulation of 4 proteins. Network analysis highlighted the interaction of proteins and pathways regulated by them, which can be targeted for neuroprotection. Validation of proteomics data highlighted that Yashtimadhu confers neuroprotection by preventing mitochondrial oxidative stress and apoptosis. This discovery will pave the way for understanding the molecular action of Ayurveda drugs and developing novel therapeutics for PD.

Targeting Ubiquitin-Proteasome Pathway by Natural Products: Novel Therapeutic Strategy for Treatment of Neurodegenerative Diseases

Misfolded proteins are the main common feature of neurodegenerative diseases, thereby, normal proteostasis is an important mechanism to regulate the neural survival and the central nervous system functionality. The ubiquitin-proteasome system (UPS) is a non-lysosomal proteolytic pathway involved in numerous normal functions of the nervous system, modulation of neurotransmitter release, synaptic plasticity, and recycling of membrane receptors or degradation of damaged and regulatory intracellular proteins. Aberrant accumulation of intracellular ubiquitin-positive inclusions has been implicated to a variety of neurodegenerative disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington disease (HD), Amyotrophic Lateral Sclerosis (ALS), and Multiple Myeloma (MM). Genetic mutation in deubiquitinating enzyme could disrupt UPS and results in destructive effects on neuron survival. To date, various agents were characterized with proteasome-inhibitory potential. Proteins of the ubiquitin-proteasome system, and in particular, E3 ubiquitin ligases, may be promising molecular targets for neurodegenerative drug discovery. Phytochemicals, specifically polyphenols (PPs), were reported to act as proteasome-inhibitors or may modulate the proteasome activity. PPs modify the UPS by means of accumulation of ubiquitinated proteins, suppression of neuronal apoptosis, reduction of neurotoxicity, and improvement of synaptic plasticity and transmission. This is the first comprehensive review on the effect of PPs on UPS. Here, we review the recent findings describing various aspects of UPS dysregulation in neurodegenerative disorders. This review attempts to summarize the latest reports on the neuroprotective properties involved in the proper functioning of natural polyphenolic compounds with implication for targeting ubiquitin-proteasome pathway in the neurodegenerative diseases. We highlight the evidence suggesting that polyphenolic compounds have a dose and disorder dependent effects in improving neurological dysfunctions, and so their mechanism of action could stimulate the UPS, induce the protein degradation or inhibit UPS and reduce protein degradation. Future studies should focus on molecular mechanisms by which PPs can interfere this complex regulatory system at specific stages of the disease development and progression.

Acetylcholinesterase: The "Hub" for Neurodegenerative Diseases and Chemical Weapons Convention

This article describes acetylcholinesterase (AChE), an enzyme involved in parasympathetic neurotransmission, its activity, and how its inhibition can be pharmacologically useful for treating dementia, caused by Alzheimer's disease, or as a warfare method due to the action of nerve agents. The chemical concepts related to the irreversible inhibition of AChE, its reactivation, and aging are discussed, along with a relationship to the current international legislation on chemical weapons.

Kavalactones from Kava (Piper methysticum) root extract as modulators of recombinant human glycine receptors

Roots of kava (Piper methysticum) plant are used in almost all Pacific Ocean cultures to prepare a drink with sedative, anesthetic and euphoric properties. One of the main active ingredients of the extract are kava lactones. Here, kava root CO2 extract and three kavalactones, DL-kavain, dihydrokavain and yangonin (isolated from whole extract by column chromatography) were tested for their inhibitory action on recombinant homomeric human α1 glycine receptors expressed in HEK293 cells. Kava CO2 root extract, as well as the individual components DL-kavain, dihydrokavain and yangonin inhibited glycine receptor activity in a dose-dependent manner. DL-kavain was the most potent inhibitor (IC50 = 0.077 ± 0.002 mm), followed by yangonin (IC50 = 0.31 ± 0.04 mm) and dihydrokavain (IC50 = 3.23 ± 0.10 mm) which were 4- and 40-fold less active than DL-kavain, respectively. Application of kava root extract did not reduce maximum currents, but increased EC50 of glycine. Simultaneous application of kava extract and strychnine showed additive inhibition, suggesting that binding of kavalactones and strychnine on the receptor is mutually exclusive. Overall, kavalactones exert a moderate inhibitory effect on the human α1 glycine receptor with DL-kavain being the most potent constituent.

Progress and perspectives of brain-targeting lipid-based nanosystems via the nasal route in Alzheimer's disease

Since health care systems dedicate substantial resources to Alzheimer's disease (AD), it poses an increasing challenge to scientists and health care providers worldwide, especially that many decades of research in the medical field revealed no optimal effective treatment for this disease. The intranasal administration route seems to be a preferable route of anti-AD drug delivery over the oral one as it demonstrates an ability to overcome the related obstacles reflected in low bioavailability, limited brain exposure and undesired pharmacokinetics or side effects. This delivery route can bypass the systemic circulation through the intraneuronal and extraneuronal pathways, providing truly needleless and direct brain drug delivery of the therapeutics due to its large surface area, porous endothelial membrane, the avoidance of the first-pass metabolism, and ready accessibility. Among the different nano-carrier systems developed, lipid-based nanosystems have become increasingly popular and have proven to be effective in managing the common symptoms of AD when administered via the nose-to-brain delivery route, which provides an answer to circumventing the BBB. The design of such lipid-based nanocarriers could be challenging since many factors can contribute to the quality of the final product. Hence, according to the authors, it is recommended to follow the quality by design methodology from the early stage of development to ensure high product quality while saving efforts and costs. This review article aims to draw attention to the up-to-date findings in the field of lipid-based nanosystems and the potential role of developing such forms in the management of AD by means of the nose-to-brain delivery route, in addition to highlighting the significant role of applying QbD methodology in this development.

Gastroprotective herbs for headache management in Persian medicine: A comprehensive review

The gut-brain axis is a bidirectional communication system that exists between the brain and gut. Several studies claimed that some types of headaches are associated with various gastrointestinal (GI) disorders. In Persian medicine (PM), physicians believed that gastric disturbances could stimulate headache and introduced some herbs for boosting gastric function as a therapeutic remedy for headache. Here we review the current evidence for the gastroprotective and antiheadache effects of herbs used in PM. Herbs used for their gastrotonic effects in PM were identified from selected Persian medical and pharmaceutical textbooks. PubMed, Scopus and Google Scholar were used to search for contemporary scientific evidence relating to the gastric and neurologic effects of these plants. A total of 24 plants were recorded from the selected sources included in this review, most of which belonged to the Rosaceae family. Phyllanthus emblica, Zingiber officinale, Boswellias errata, Punica granatum and Hypericum perforatum had the most recent studies related to GI disorder and headache, while current research about quince, rose, apple, hawthorn and pear was limited. Reducing Helicobacter pylori growth, gastritis, erosion of the stomach lining, hemorrhage and perforation, improving gastric mucosal resistance, antisecretary, antiulcer, antipyretic, analgesic, sedative, anxiolytic, anti-inflammatory, anticonvulsant, neuroprotective and antioxidant effects as well as improvement in memory scores were some of the gastrotonic and neuroprotective mechanisms described in the current research. These results confirmed that medicinal plants prescribed in PM may improve headache in patients through the management of GI abnormalities. However, further studies are recommended to investigate the efficacy and safety of the mentioned medicinal plants.

Vasodilatory Effects and Mechanisms of Action of Bacopa monnieri Active Compounds on Rat Mesenteric Arteries

B. monnieri extract (BME) is an abundant source of bioactive compounds, including saponins and flavonoids known to produce vasodilation. However, it is unclear which components are the more effective vasodilators. The aim of this research was to investigate the vasorelaxant effects and mechanisms of action of saponins and flavonoids on rat isolated mesenteric arteries using the organ bath technique. The vasorelaxant mechanisms, including endothelial nitric oxide synthase (eNOS) pathway and calcium flux were examined. Saponins (bacoside A and bacopaside I), and flavonoids (luteolin and apigenin) at 0.1-100 µM caused vasorelaxation in a concentration-dependent manner. Luteolin and apigenin produced vasorelaxation in endothelial intact vessels with more efficacy (Emax 99.4 ± 0.7 and 95.3 ± 2.6%) and potency (EC50 4.35 ± 1.31 and 8.93 ± 3.33 µM) than bacoside A and bacopaside I (Emax 83.6 ± 2.9 and 79.9 ± 8.2%; EC50 10.8 ± 5.9 and 14.6 ± 5.4 µM). Pretreatment of endothelial intact rings, with L-NAME (100 µM); an eNOS inhibitor, or removal of the endothelium reduced the relaxant effects of all compounds. In K+-depolarised vessels suspended in Ca2+-free solution, these active compounds inhibited CaCl2-induced contraction in endothelial denuded arterial rings. Moreover, the active compounds attenuated transient contractions induced by 10 µM phenylephrine in Ca2+-free medium containing EGTA (1 mM). Thus, relaxant effects occurred in both endothelial intact and denuded vessels which signify actions through both endothelium and vascular smooth muscle cells. In conclusion, the flavonoids have about twice the potency of saponins as vasodilators. However, in the BME, there is ~20 × the amount of vaso-reactive saponins and thus are more effective.

Natural Diterpenoid Oridonin Ameliorates Experimental Autoimmune Neuritis by Promoting Anti-inflammatory Macrophages Through Blocking Notch Pathway

The diterpenoid compound, Oridonin, extracted from the Chinese herb, Rabdosia rubescens, possesses multiple biological activities and properties. Oridonin exhibited efficient anti-inflammatory activity by inducing a switch in macrophage polarization to the anti-inflammatory phenotype through inhibition of the Notch pathway in our in vitro study; therefore, its potential therapeutic effects were further investigated in the animal model of human Guillain-Barré syndrome (GBS) and other polyneuropathies - experimental autoimmune neuritis (EAN). Either preventive or therapeutic treatments with Oridonin greatly attenuated disease peak severity, suppressed paraparesis, shortened disease duration, and even delayed EAN onset. Progression of neuropathic pain, demyelination, inflammatory cellular accumulations, and inflammatory cytokines in peripheral nerves were significantly attenuated. Meanwhile, accumulation of immune cells in the spinal roots and microglial activation in the lumbar spinal cord were also reduced. Interestingly, Oridonin treatment significantly increased the proportion of anti-inflammatory macrophages and made them locally dominant among all infiltrated macrophages in the peripheral nerves. The down-regulation of local Notch pathway proteins, together with our in vitro results indicated their possible involvement. Taken together, our results demonstrated that Oridonin effectively suppressed EAN by attenuating local inflammatory reaction and increasing the proportion of immune regulating macrophages in the peripheral nerves, possibly through blockage of the Notch pathway, which suggests Oridonin as a potential therapeutic candidate for human GBS and neuropathies.

Bacopa monnieri prevents colchicine-induced dementia by anti-inflammatory action

Inflammation is considered as an early event in the development of Alzheimer's disease (AD) that precedes the formation of Aβ plaques and neurofibrillary tangles. Therefore, strategies aimed at attenuating inflammation by phytochemicals may be a potential therapeutic intervention against AD. The present study was designed to evaluate if colchicine-induced inflammation and Aβ production could be prevented by Bacopa monnieri (BM) supplementation. Dementia was induced by a single intracerebroventicular injection of colchicine (15 μg/5 μl), whereas, BM extract was administered orally (50 mg/kg body weight, daily) for 15 days. Assessment of cognitive functions using Morris water maze revealed deficits in colchicine administered animals. This was accompanied by significant increase in oxidative stress in terms of accentuated ROS and NO production. Expression of pro-inflammatory cytokines (IL-6, TNF-α) and chemokine (MCP-1) increased in the brain regions. Furthermore, COX-2 and iNOS expression also increased significantly in the brain regions of colchicine-administered animals. In addition, BACE-1 activity increased in the colchicine treated animals, which was accompanied by enhanced Aβ production. On the other hand, BM supplementation was able to improve cognitive functions, suppress Aβ formation by reducing BACE-1 activity. Inflammatory and oxidative stress markers were attenuated in the brain regions of BM supplemented animals. Taken together, the findings reveal that BM reverses colchicine-induced dementia by its anti-inflammatory and anti-oxidant action suggesting that it may be an effective therapeutic intervention to ameliorate progression of AD.

Hyperglycemia-induced oxidative brain injury: Therapeutic effects of Cola nitida infusion against redox imbalance, cerebellar neuronal insults, and upregulated Nrf2 expression in type 2 diabetic rats

The therapeutic effect of the hot water infusion of Cola nitida against hyperglycemia-induced neurotoxicity, cerebellar neurodegeneration and elemental deregulations was investigated in fructose-streptozotocin induced rat model of type 2 diabetes (T2D). A diabetic group was administered drinking water, two other diabetic groups were treated with C. nitida at 150 and 300 mg/kg bodyweight respectively, while another group was administered metformin (200 mg/kg bodyweight). Two other groups consisting of normal rats, were administered drinking water and C. nitida (300 mg/kg bodyweight). After 6 weeks of treatment, their brains were collected. Treatment with C. nitida led to suppression of oxidative stress, significantly elevating reduced glutathione (GSH) levels, superoxide dismutase and catalase activities, concomitant with depletion of malondialdehyde (MDA) levels. Acetylcholinesterase and ATPase activities were significantly inhibited in C. nitida-treated diabetic rats. Histological and microscopic analysis also revealed a restorative effect of C. nitida on T2D-altered distribution of elements, neurons and axonal nodes. Treatment with C. nitida also led to significant inhibition of Nrf2 expression in the cerebellar cortex. These results suggest the therapeutic effects of C. nitida in maintenance of the neuronal integrity and antioxidant status of the brain in T2D. These neuroprotective activities can be attributed to the identified alkaloid, caffeine in the infusion.

Antidepressant Effect of Tetragonia tetragonoides (Pall.) Kuntze Extract on Serotonin Turnover

Tetragonia tetragonoides (Pall.) Kuntze (TTK) is a groundcover found along coastal areas of the Korean peninsula. TTK is traditionally used to improve women's health and treat gastrointestinal diseases. Use of herbal medicines in the treatment of mood disorders has recently been suggested as an alternative therapeutic strategy. In the present study, we determined that consumption of TTK extract ameliorated progression of depressive-like symptoms in ovariectomized (OVX) rats and further examined the mechanisms involved, i.e., synthesis, release, and reuptake(s) of serotonin (also known as 5-HT). We assessed the mRNA expression levels of tryptophan hydroxylases (TPH-1 and TPH-2) and serotonin transporter (SERT) as well as the reuptake activity of serotonin in RBL-2H3 cells. We also determined whether or not TTK extract regulates the serum level of serotonin and improves depressive-like symptoms in 0.5, 1, and 2% TTK-fed OVX female rats in a forced swimming test. Our results show that the mRNA levels of TPH-1 and SERT were significantly reduced, whereas the mRNA level of TPH-2 was dose-dependently elevated by TTK (50 and 100 μg/mL) in RBL-2H3 cells. TTK significantly inhibited LPS- (lipopolysaccharide-) induced serotonin uptake in RBL-2H3 cells in a dose-dependent manner. The serum level(s) of serotonin was elevated by 1% and 2% TTK treatment in OVX female rats. Moreover, immobility time in the forced swimming test was reduced by 1% and 2% TTK treatment but not altered by 0.5% TTK treatment in OVX female rats. Taken together, these results indicate that TTK may significantly inhibit depressive-like symptoms due to upregulation of serotonin level(s) and regulation of serotonin reuptake activity. Thus, TTK may exert beneficial effects on depression during pre- or/and postmenopausal periods via modulation of serotonin synthesis and metabolism.

Drug–DNA interaction, a joint DFT-D3/MD study on safranal as an anticancer and DNA nanostructure model

In this research, using a combination of quantum mechanics and molecular dynamic (MD) simulations, the interaction of safranal (2,6,6-trimethylcyclohexa-1,3-dien-1-carboxaldehyde) as an anti-cancer drug and Dickerson B-DNA was studied. MD simulations were executed for 35 ns in water. Binding energy analysis in three definite parts of the B-DNA and comparison between different contributions of the binding energy shows that the van der Waals energy part of the interaction is impressive among the standard molecular mechanic energy terms. On the basis of Gibbs energies, it is confirmed that the most important interactions in the safranal complex are related to the A–T and C–G rich regions, which is in agreement with the experimental data. Quantum theory of atoms in molecules and natural bond orbital analyses were applied. A diminution in the electronic chemical potential of the safranal–DNA complex in comparison with the isolated DNA, 0.026 and 0.022 au for the S1 region and 0.012 and 0.017 au for the S2 region, was obtained in the gas phase and water, respectively, which increases the complex stability. An enhancement in the electrophilicity character, during the complexation process, shows the electron charge flux between the safranal and DNA, especially in water. The strengths of the CH⋯O bonds at the center of safranal–DNA interaction were also evaluated. A mean value of 0.06 au for the electron density of the bond critical point of the H⋯O in the complex confirms the H-bond formation during the complexation.

Bacopa monnieri extract improves novel object recognition, cell proliferation, neuroblast differentiation, brain-derived neurotrophic factor, and phosphorylation of cAMP response element-binding protein in the dentate gyrus

Bacopa monnieri is a medicinal plant with a long history of use in Ayurveda, especially in the treatment of poor memory and cognitive deficits. In the present study, we hypothesized that Bacopa monnieri extract (BME) can improve memory via increased cell proliferation and neuroblast differentiation in the dentate gyrus. BME was administered to 7-week-old mice once a day for 4 weeks and a novel object recognition memory test was performed. Thereafter, the mice were euthanized followed by immunohistochemistry analysis for Ki67, doublecortin (DCX), and phosphorylated cAMP response element-binding protein (CREB), and western blot analysis of brain-derived neurotrophic factor (BDNF). BME-treated mice showed moderate increases in the exploration of new objects when compared with that of familiar objects, leading to a significant higher discrimination index compared with vehicle-treated mice. Ki67 and DCX immunohistochemistry showed a facilitation of cell proliferation and neuroblast differentiation following the administration of BME in the dentate gyrus. In addition, administration of BME significantly elevated the BDNF protein expression in the hippocampal dentate gyrus, and increased CREB phosphorylation in the dentate gyrus. These data suggest that BME improves novel object recognition by increasing the cell proliferation and neuroblast differentiation in the dentate gyrus, and this may be closely related to elevated levels of BDNF and CREB phosphorylation in the dentate gyrus.