The coumarin scopoletin potentiates acetylcholine release from synaptosomes, amplifies hippocampal long-term potentiation and ameliorates anticholinergic- and age-impaired memory

Regulation of adipocyte differentiation and lipid metabolism by novel synthetic chromenes exploring anti-obesity and broader therapeutic potential

Obesity poses a significant global health challenge, necessitating the search for novel therapeutic agents to address this epidemic. Chromenes, known for their diverse bioactivities, hold promise as potential anti-obesity compounds, yet research in this area remains limited. This pioneering study represents the first exploration of synthetic chromenes as potential anti-obesity agents, unveiling the underlying molecular pathways governing adipogenesis and lipolysis. Twenty-nine chromenes were synthesized using green chemistry approaches, resulting in five novel compounds: 1, 2, 3, 4, and 5. Among them, 14 chromenes demonstrated a lack of toxicity to pre-adipocytes (PAs) and mature adipocytes (MAs) of 3T3-L1 cells. The anti-adipogenesis and lipolysis enhancement potential of these non-toxic 14 chromenes were comprehensively evaluated using Oil Red O staining technique, LDH activity measurement, and glycerol release assays. Notably, 4, 5, 21 and 25 exhibited remarkable efficacy in reducing intracellular lipid accumulation without inducing cellular stress or cell death. Molecular analysis revealed significant alterations in the expression of key transcription factors involved in adipogenesis and lipid metabolism, including PPARγ, C/EBPα, ADD-1, Pref-1, IRS-1, GLUT-4, adiponectin, FAS, aP2, ATGL, and HSL. This suggests their potential role in anti-adipogenesis. Additionally, the treatments with 4 and 25 showed potential for enhancing lipolysis, providing further evidence of their anti-obesity properties. This study presents several promising prospects for the development of synthetic chromenes as potential anti-obesity agents, opening new avenues for drug discovery and benefitting individuals worldwide in addressing obesity-related challenges to human health. In addition, predictive in silico modeling was performed on the identified candidate chromenes. This modeling provides prospective anti-HIV activity, pharmacokinetic, metabolism, and permeability data, setting the groundwork for further investigation into these potential new chemical entities.

Scopoletin: a review of its pharmacology, pharmacokinetics, and toxicity

Scopoletin is a coumarin synthesized by diverse medicinal and edible plants, which plays a vital role as a therapeutic and chemopreventive agent in the treatment of a variety of diseases. In this review, an overview of the pharmacology, pharmacokinetics, and toxicity of scopoletin is provided. In addition, the prospects and outlook for future studies are appraised. Scopoletin is indicated to have antimicrobial, anticancer, anti-inflammation, anti-angiogenesis, anti-oxidation, antidiabetic, antihypertensive, hepatoprotective, and neuroprotective properties and immunomodulatory effects in both in vitro and in vivo experimental trials. In addition, it is an inhibitor of various enzymes, including choline acetyltransferase, acetylcholinesterase, and monoamine oxidase. Pharmacokinetic studies have demonstrated the low bioavailability, rapid absorption, and extensive metabolism of scopoletin. These properties may be associated with its poor solubility in aqueous media. In addition, toxicity research indicates the non-toxicity of scopoletin to most cell types tested to date, suggesting that scopoletin will neither induce treatment-associated mortality nor abnormal performance with the test dose. Considering its favorable pharmacological activities, scopoletin has the potential to act as a drug candidate in the treatment of cancer, liver disease, diabetes, neurodegenerative disease, and mental disorders. In view of its merits and limitations, scopoletin is a suitable lead compound for the development of new, efficient, and low-toxicity derivatives. Additional studies are needed to explore its molecular mechanisms and targets, verify its toxicity, and promote its oral bioavailability.

Modulators of nicotine reward and reinforcement

Nicotine has been well-characterized for its ability to alter neurophysiology to promote rewarding and reinforcing properties. However, several exogenous chemicals possess properties that modulate or enhance nicotine's ability to alter neurophysiology. This chapter focuses on nicotine's impact on behavior through changes in neurophysiology and several chemical entities that in-turn modulate nicotine's ability to act as a neuromodulator.

Conocarpus lancifolius (Combretaceae): Pharmacological Effects, LC-ESI-MS/MS Profiling and In Silico Attributes

In folklore medicine, Conocarpus lancifolius is used to treat various illnesses. The main objective of this study was a comprehensive investigation of Conocarpus lancifolius leaf aqueous extract (CLAE) for its antioxidant, cardioprotective, anxiolytic, antidepressant and memory-enhancing capabilities by using different in vitro, in vivo and in silico models. The in vitro experimentation revealed that CLAE consumed an ample amount of total phenolics (67.70 ± 0.15 µg GAE/mg) and flavonoids (47.54 ± 0.45 µg QE/mg) with stronger antiradical effects through DPPH (IC₅₀ = 16.66 ± 0.42 µg/mL), TAC (77.33 ± 0.41 µg AAE/mg) and TRP (79.11 ± 0.67 µg GAE/mg) assays. The extract also displayed suitable acetylcholinesterase (AChE) inhibitory (IC₅₀ = 110.13 ± 1.71 µg/mL) activity through a modified Ellman's method. The toxicology examination presented no mortality or any signs of clinical toxicity in both single-dose and repeated-dose tests. In line with the cardioprotective study, the pretreatment of CLAE was found to be effective in relieving the isoproterenol (ISO)-induced myocardial injury in rats by normalizing the heart weight index, serum cardiac biomarkers, lipid profile and various histopathological variations. In the noise-stress-induced model for behavior attributes, the results demonstrated that CLAE has the tendency to increase the time spent in the central zone and elevated open arms in the open field and elevated plus maze tests (examined for anxiety assessment), reduced periods of immobility in the forced swimming test (for depression) and improved recognition and working memory in the novel object recognition and Morris water maze tests, respectively. Moreover, the LC-ESI-MS/MS profiling predicted 53 phytocompounds in CLAE. The drug-likeness and ADMET analysis exhibited that the majority of the identified compounds have reasonable physicochemical and pharmacokinetic profiles. The co-expression of molecular docking and network analysis indicated that top-ranked CLAE phytoconstituents act efficiently against the key proteins and target multiple signaling pathways to exert its cardiovascular-protectant, anxiolytic, antidepressant and memory-enhancing activity. Hence, this artifact illustrates that the observed biological properties of CLAE elucidate its significance as a sustainable source of bioactive phytochemicals, which appears to be advantageous for pursuing further studies for the development of new therapeutic agents of desired interest.

Recent Advances in Biologically Active Coumarins from Marine Sources: Synthesis and Evaluation

Coumarin and its derivatives have significantly attracted the attention of medicinal chemists and chemical biologists due to their huge range of biological, and in particular, pharmacological properties. Interesting families of coumarins have been found from marine sources, which has accelerated the drug discovery process by inspiring innovation or even by the identification of analogues with remarkable biological properties. The purpose of this review is to showcase the most interesting marine-derived coumarins from a medicinal chemistry point of view, as well as the novel and useful synthetic routes described to date to achieve these chemical structures. The references that compose this overview were collected from PubMed, Mendeley and SciFinder.

Coumarins as Fungal Metabolites with Potential Medicinal Properties

Coumarins are a structurally varied set of 2H-chromen-2-one compounds categorized also as members of the benzopyrone group of secondary metabolites. Coumarin derivatives attract interest owing to their wide practical application and the unique reactivity of fused benzene and pyrone ring systems in molecular structure. Coumarins have their own specific fingerprints as antiviral, antimicrobial, antioxidant, anti-inflammatory, antiadipogenic, cytotoxic, apoptosis, antitumor, antitubercular, and cytotoxicity agents. Natural products have played an essential role in filling the pharmaceutical pipeline for thousands of years. Biological effects of natural coumarins have laid the basis of low-toxic and highly effective drugs. Presently, more than 1300 coumarins have been identified in plants, bacteria, and fungi. Fungi as cultivated microbes have provided many of the nature-inspired syntheses of chemically diverse drugs. Endophytic fungi bioactivities attract interest, with applications in fields as diverse as cancer and neuronal injury or degeneration, microbial and parasitic infections, and others. Fungal mycelia produce several classes of bioactive molecules, including a wide group of coumarins. Of promise are further studies of conditions and products of the natural and synthetic coumarins' biotransformation by the fungal cultures, aimed at solving the urgent problem of searching for materials for biomedical engineering. The present review evaluates the fungal coumarins, their structure-related peculiarities, and their future therapeutic potential. Special emphasis has been placed on the coumarins successfully bioprospected from fungi, whereas an industry demand for the same coumarins earlier found in plants has faced hurdles. Considerable attention has also been paid to some aspects of the molecular mechanisms underlying the coumarins' biological activity. The compounds are selected and grouped according to their cytotoxic, anticancer, antibacterial, antifungal, and miscellaneous effects.

Resistance training and Urtica dioica increase neurotrophin levels and improve cognitive function by increasing age in the hippocampus of rats

INTRODUCTION

Inflammation and oxidative stress are two major factors in accelerating brain aging. Consumption of some traditional herbs with antioxidant and anti-inflammatory properties such as Urtica dioica extract (Ud) and resistance training (RT) may be effective in controlling premature aging and memory impairment. Therefore, we hypothesized that the combined effect of RT and Ud might play an essential role in preventing memory disorders and hippocampal tissue changes caused by increasing age in rats.

METHODS

28 male Wistar rats (24-week) were divided into 4-groups (n = 7): control (C), Ud, RT, and Ud+RT. RT groups were trained for five weeks, and Ud extract in the 0.0166 w/v concentration (50 mg/kg, oral/daily) was administered. We also examined the effects of RT and Ud on the behavioral (memory and learning), histological (the morphological changes in the dentate gyrus), and transcript aspects of hippocampal tissue.

RESULTS

Aging led to karyopyknosis in the hippocampal tissue, which was alleviated by RT and Ud supplementation. RT and Ud were accompanied by increased GPx, GSH, GAP-43, and decreased CAP-1 levels in the hippocampus. Moreover, RT and Ud led to increased NGF, BDNF, and GAP-43 levels, decreased MDA, and protection of hippocampal tissue from karyopyknosis, which was associated with cognitive improvement. However, these interventions had no significant effect on the hippocampal levels of IL-1β, SOD, and CAT.

CONCLUSIONS

These findings suggest that increasing age decreases hippocampal NGF, BDNF, and GAP-43 levels and impairs cognition, which may be reversed by regular RT and Ud extract.

Novel insights on acetylcholinesterase inhibition by Convolvulus pluricaulis, scopolamine and their combination in zebrafish

Acetylcholinesterase (AChE) inhibitors increase the retention of acetylcholine (ACh) in synapses. Although they alleviate cognitive deficits in Alzheimer's disease, their limited benefits warrant investigations of plant extracts with similar properties. We studied the anti-AChE activity of Convolvulus pluricaulis (CP) in a zebrafish model of cognitive impairment induced by scopolamine (SCOP). CP is a perennial herb with anti-amnesiac and anxiolytic properties. It contains alkaloid, anthocyanin, coumarin, flavonoid, phytosterol and triterpenoid components. Isoxazole (ISOX) was used as a positive control for AChE inhibition. CP-treated 168 hpf larvae showed a similar pattern of AChE inhibition (in the myelencephalon and somites) as that of ISOX-treated larvae. CP was superior to ISOX as evidenced by the retention of avoidance response behavior in adult zebrafish. Molecular docking studies indicated that ISOX binds Ser203 of the catalytic triad on the human AChE. The active components of CP-scopoletin and kaempferol-were bound by His447 of the catalytic triad, the anionic subsite of the catalytic center, and the peripheral anionic site. This suggested the ability of CP to mediate both competitive and non-competitive modes of inhibition. Surprisingly, SCOP showed AChE inhibition in larvae, possibly mediated via the choline-binding sites. CP + SCOP induced a concentration-dependent increase in AChE inhibition and ACh depletion. Abnormal motor responses were observed with ISOX, CP, ISOX + SCOP, and CP + SCOP, indicative of undesirable effects on the peripheral cholinergic system. Our study proposes the examination of CP, SCOP, and CP + SCOP as potential AChE inhibitors for their ability to modulate cognitive deficits.

Evaluation of Scopoletin from Penicillium janthinellum Snef1650 for the Control of Heterodera glycines in Soybean

Soybean cyst nematode (SCN) (Heterodera glycines Ichinohe) is responsible for causing a major soybean disease globally. The fungal strain Penicillium janthinellum Snef1650 was evaluated against H. glycines. However, the effective determinants of the P. janthinellum strain are unknown. By performing pot experiments, a functioning compound was isolated from P. janthinellum Snef1650 through organic solvent extraction, semi-preparative HPLC, Sephadex LH-20 column chromatography, and silica gel column chromatography, and the isolated compound was identified to be scopoletin through 1H NMR, 13C NMR, and HPLC–MS. The pot experiments indicated that the treatment of soybean seeds with scopoletin drastically reduced the SCN population. The field experiments performed in 2017 and 2018 revealed that scopoletin decreased over 43.7% juveniles in the roots and over 61.55% cysts in the soil. Scopoletin treatment also promoted soybean growth and improved its yield, with an increase in plot yield by >5.33%. Scopoletin obtained from P. janthinellum Snef1650 could be used as an anti-H. glycines biocontrol agent.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Artemisia scoparia: Traditional uses, active constituents and pharmacological effects

ETHNOPHARMACOLOGICAL RELEVANCE

Artemisia scoparia Waldst.et Kit (A. scoparia), is an important medicinal plant mainly distributed in China, Korea, Japan, Pakistan, India, Central Europe, Saudi Arabia and Iran. It has been used for a long history to treat fever, inflammation, jaundice, and infection, but systematic reviews about the medicinal uses of A. scoparia are still lacking.

AIM OF THE STUDY

This review is to provide up-to-date information on A. scoparia, including its botanical characteristics, medicinal resources, traditional uses, phytochemistry and pharmacological effects, in exploring therapeutic and scientific potentials.

MATERIALS AND METHODS

The information related to this article was systematically collected from the scientific literature databases including PubMed, Google Scholar, Web of Science, Science Direct, Springer, China National Knowledge Infrastructure, local books, PhD and MS dissertations, and other web sources.

RESULTS

Herein a total of 102 compounds, such as flavonoids, coumarins, chromones, steroids, volatile oil and phenolic acid isolated from A. scoparia are summarized. Among these compounds, the effects of flavonoids, coumarins and phenolic acids were extensively studied. We have comprehensively summarized modern pharmacological studies on A. scoparia and demonstrated A. scoparia and its active components have a wide range of pharmaceutical activities, such as anticancer, anti-inflammatory, antibacterial, liver protection, antiatherogenic, antiviral as well as neuroprotective functions.

CONCLUSIONS

As an important Chinese medicinal plant, modern pharmacological studies have demonstrated that A. scoparia has diverse bioactivities, especially on liver protection and anti-inflammatory activities. These prominent bioactivities highlight prospects on new drug development. Nevertheless, the comprehensive evaluation, long-term in vivo toxicity, and clinical efficacy of A. scoparia require further in-depth research.

Potential benefits of phytochemicals from Azadirachta indica against neurological disorders

Azadirachta indica or Neem has been extensively used in the Indian traditional medical system because of its broad range of medicinal properties. Neem contains many chemically diverse and structurally complex phytochemicals such as limonoids, flavonoids, phenols, catechins, gallic acid, polyphenols, nimbins. These phytochemicals possess vast array of therapeutic activities that include anti-feedant, anti-viral, anti-malarial, anti-bacterial, anti-cancer properties. In recent years, many phytochemicals from Neem have been shown to be beneficial against various neurological disorders like Alzheimer's and Parkinson's disease, mood disorders, ischemic-reperfusion injury. The neuroprotective effects of the phytochemicals from Neem are primarily mediated by their anti-oxidant, anti-inflammatory and anti-apoptotic activities along with their ability to modulate signaling pathways. However, extensive studies are still required to fully understand the molecular mechanisms involved in neuropotective effects of phytochemicals from Neem. This review is an attempt to cover the neuroprotective properties of various phytochemicals from Neem along with their mechanism of action so that the potential of the compounds could be realized to reduce the burden of neurodegenerative diseases.

Fungal Endophytes as Efficient Sources of Plant-Derived Bioactive Compounds and Their Prospective Applications in Natural Product Drug Discovery: Insights, Avenues, and Challenges

Fungal endophytes are well-established sources of biologically active natural compounds with many producing pharmacologically valuable specific plant-derived products. This review details typical plant-derived medicinal compounds of several classes, including alkaloids, coumarins, flavonoids, glycosides, lignans, phenylpropanoids, quinones, saponins, terpenoids, and xanthones that are produced by endophytic fungi. This review covers the studies carried out since the first report of taxol biosynthesis by endophytic Taxomyces andreanae in 1993 up to mid-2020. The article also highlights the prospects of endophyte-dependent biosynthesis of such plant-derived pharmacologically active compounds and the bottlenecks in the commercialization of this novel approach in the area of drug discovery. After recent updates in the field of 'omics' and 'one strain many compounds' (OSMAC) approach, fungal endophytes have emerged as strong unconventional source of such prized products.

Artemisia scoparia and Metabolic Health: Untapped Potential of an Ancient Remedy for Modern Use

Botanicals have a long history of medicinal use for a multitude of ailments, and many modern pharmaceuticals were originally isolated from plants or derived from phytochemicals. Among these, artemisinin, first isolated from Artemisia annua, is the foundation for standard anti-malarial therapies. Plants of the genus Artemisia are among the most common herbal remedies across Asia and Central Europe. The species Artemisia scoparia (SCOPA) is widely used in traditional folk medicine for various liver diseases and inflammatory conditions, as well as for infections, fever, pain, cancer, and diabetes. Modern in vivo and in vitro studies have now investigated SCOPA's effects on these pathologies and its ability to mitigate hepatotoxicity, oxidative stress, obesity, diabetes, and other disease states. This review focuses on the effects of SCOPA that are particularly relevant to metabolic health. Indeed, in recent years, an ethanolic extract of SCOPA has been shown to enhance differentiation of cultured adipocytes and to share some properties of thiazolidinediones (TZDs), a class of insulin-sensitizing agonists of the adipogenic transcription factor PPARγ. In a mouse model of diet-induced obesity, SCOPA diet supplementation lowered fasting insulin and glucose levels, while inducing metabolically favorable changes in adipose tissue and liver. These observations are consistent with many lines of evidence from various tissues and cell types known to contribute to metabolic homeostasis, including immune cells, hepatocytes, and pancreatic beta-cells. Compounds belonging to several classes of phytochemicals have been implicated in these effects, and we provide an overview of these bioactives. The ongoing global epidemics of obesity and metabolic disease clearly require novel therapeutic approaches. While the mechanisms involved in SCOPA's effects on metabolic, anti-inflammatory, and oxidative stress pathways are not fully characterized, current data support further investigation of this plant and its bioactives as potential therapeutic agents in obesity-related metabolic dysfunction and many other conditions.

Bajitianwan attenuates D-galactose-induced memory impairment and bone loss through suppression of oxidative stress in aging rat model

ETHNOPHARMACOLOGICAL RELEVANCE

Osteoporosis and Alzheimer's disease (AD) are both senile diseases, which are closely related to oxidative stress. Bajitianwan (BJTW) is a classic Chinese formulation consisting of seven herbal drugs: the root of Morinda officinalis F.C.How., root and rhizome of Acorus tatarinowii Schott, the root bark of Lycium chinense Mill., the sclerotium of Poria cocos (Schw.) Wolf, the root of Polygala tenuifolia Willd., sclerotium with host wood of Poria cocos (Schw.) Wolf and root and rhizome of Panax ginseng C. A. Mey. BJTW has been used for the treatment of osteoporosis and AD for hundreds of years.

AIM OF THE STUDY

This study aimed to investigate the protective effects of BJTW in the amelioration of memory impairment and bone loss induced by D-galactose and to explore the underlying mechanism.

MATERIALS AND METHODS

The aging model was established in male Wistar rats by subcutaneous injection of D-galactose (100 mg/kg), and the rats were treated with huperzine-A, alendronate sodium, or the aqueous extract of BJTW for 4 months. Cognitive performance was evaluated with the Morris water maze. Rat femurs were scanned using microcomputed tomography to obtain three-dimensional imagery of bone microstructure. The impact of D-galactose on the expression of Forkhead box O1 and superoxide dismutase 2 in femur tissue was also evaluated.

RESULTS

For the model group, BJTW treatment significantly reduced the latency time for finding the target platform in the directional swimming test and increased time spent swimming in the target quadrant with the probe test. Additionally, BJTW treatment alleviated D-galactose-induced bone loss through regulation of levels of alkaline phosphatase, osteocalcin, osteoprotegerin, and receptor activator of nuclear factor kappa B ligand. Furthermore, BJTW treatment increased catalase and glutathione peroxidase levels in serum, reduced malondialdehyde content in hippocampus, and upregulated expression of Forkhead O1, which upregulated superoxide dismutase 2 in the femur.

CONCLUSIONS

BJTW had positive effects on age-related memory impairments and bone loss. It may be a promising antioxidant candidate for treatment of Alzheimer's disease and osteoporosis.

Convolvulus pluricaulis extract can modulate synaptic plasticity in rat brain hippocampus

The memory-boosting property of Indian traditional herb, Convolvulus pluricaulis, has been documented in literature; however, its effect on synaptic plasticity has not yet been reported. Two important forms of synaptic plasticity known to be involved in the processes of memory formation are long-term potentiation (LTP) and long-term depression (LTD). In the present study, the effect of C. pluricaulis plant extract on LTP and LTD were evaluated. The adult male Wistar rats were fed orally with 250, 500 and 1000 mg/kg of this extract for 4 weeks and the effect was determined on LTP and LTD in the Schaffer collaterals of the hippocampal cornu ammonis region CA1. We found that the 500 mg/kg dose of the extract could significantly enhance LTP compared to the vehicle treated ones. Moreover, the same dose could also reduce LTD while used in a separate set of animals. Also, a fresh group of animals treated with the effective dose (500 mg/kg) of plant extract were examined for memory retention in two behavioral platforms namely, contextual fear conditioning (CFC) and novel object recognition test (NORT). Increased fear response to the conditioned stimulus and enhanced recognition of objects were observed in CFC and NORT, respectively, both indicating strengthening of memory. Following up, ex-vivo electrophysiology experiments were performed with the active single molecule scopoletin, present in C. pluricaulis extract and similar patterns in synaptic plasticity changes were obtained. These findings suggest that prolonged treatment of C. pluricaulis extract, at a specific dose in healthy animals, can augment memory functions by modulating hippocampal plasticity.

Osthole alleviates neuropathic pain in mice by inhibiting the P2Y1-receptor-dependent JNK signaling pathway

There are many reports about natural products relieving neuralgia. Osthole is the main component of Angelica biserrata Yuan et Shan, a natural product that treats rheumatism through the elimination of inflammation and the alleviation of pain that has a long history in the clinic. The analgesic mechanism of osthole is complicated and confusing. Astrocytes have attracted increasing attention from pain researchers. Inhibitors targeting astrocytes are thought to be promising treatments for neuropathic pain. Whether osthole can alleviate neuropathic pain through astrocytes has not been elucidated in detail. In this study, CCI surgery was used to establish the neuropathic pain model in mice. The CCI mice were treated with osthole (5, 10, or 20 mg/kg/day) for 14 days in vivo. Mechanical allodynia and heat hyperalgesia were measured to evaluate the therapeutic effect of osthole. In mechanism research, the activation of astrocytes; the protein expression of P2Y₁R and p-JNK in astrocytes; the release of inflammatory factors; the variations in mEPSPs and eEPSPs; and the levels of GluA1, GluN2B, p-ERK, p-CREB and c-Fos in neurons were observed. The P2Y₁R inhibitor MRS2179 and the p-JNK inhibitor SP600125 were used to demonstrate how osthole works in neuropathic pain. In addition, astrocytes and neurons were used to estimate the direct effect of osthole on astrocyte-neuron interactions and signal transmission in vitro. Our findings suggest that osthole treatment obviously relieved mechanical allodynia and heat hyperalgesia in CCI mice. P2Y₁R is involved in CCI-induced pain hypersensitivity, and P2Y₁R is required for osthole-induced p-JNK downregulation in the spinal cord. Osthole inhibited astrocyte activation and reduced inflammatory factor expression. After osthole treatment, mEPSP frequency and eEPSP amplitude were decreased in spinal lamina I-II neurons. Downstream signaling molecules such as pGluA1, pGluN2B, p-ERK, p-CREB and c-Fos were also reduced very quickly in osthole-treated neuralgic mice. Our conclusion is that osthole alleviates neuropathic pain in mice via the P2Y₁-receptor-dependent JNK signaling pathway in spinal astrocytes, and osthole could be considered a potential pharmacotherapy to alleviate neuropathic pain.

Characterization of coumarins from Ipomoea mauritiana Jacq by LC-APCI-MS/MS analysis and evaluation of its anti-amnesic activity

Background

Ipomoea mauritiana is one of the source plants of Vidari, an Ayurvedic drug used as Medhyarasayana (rejuvenating drug). In this current study, coumarins were separated from tuberous root of I. mauritiana and characterization of the coumarin fraction was done by LC-MS/MS analysis by atmospheric pressure chemical ionization method. Anti-amnesic activity was evaluated against scopolamine induced amnesia in Wistar rats.

Results

Mass spectroscopic characterization of coumarin fraction directed to the tentative identification of coumarins such as 7-hydroxy-6-methoxy coumarin, 7-hydroxycoumarin, 5-methoxy-6,7-furanocoumarin, 5,7-dimethoxycoumarin, and 6-hydroxy-7-methoxy-4-phenylcoumarin. Aqueous extract of I. mauritiana at a dose of 100 and 200 mg/kg showed significant anti-amnesic activity against scopolamine-induced changes in step through latency and working memory errors.

Conclusion

The findings of the study showed that I. mauritiana is a rich source of coumarins and possessed significant anti-amnesic activity. The study concluded the scientific basis of using I. mauritiana as rejuvenating drug in Ayurveda.

Graphical abstract

Malva parviflora extract ameliorates the deleterious effects of a high fat diet on the cognitive deficit in a mouse model of Alzheimer's disease by restoring microglial function via a PPAR-γ-dependent mechanism

Background

Alzheimer’s disease (AD) is a neuropathology strongly associated with the activation of inflammatory pathways. Accordingly, inflammation resulting from obesity exacerbates learning and memory deficits in humans and in animal models of AD. Consequently, the long-term use of non-steroidal anti-inflammatory agents diminishes the risk for developing AD, but the side effects produced by these drugs limit their prophylactic use. Thus, plants natural products have become an excellent option for modern therapeutics. Malva parviflora is a plant well known for its anti-inflammatory properties.

Methods

The present study was aimed to determine the anti-inflammatory potential of M. parviflora leaf hydroalcoholic extract (MpHE) on AD pathology in lean and obese transgenic 5XFAD mice, a model of familial AD. The inflammatory response and Amyloid β (Aβ) plaque load in lean and obese 5XFAD mice untreated or treated with MpHE was evaluated by immunolocalization (Iba-1 and GFAP) and RT-qPCR (TNF) assays and thioflavin-S staining, respectively. Spatial learning memory was assessed by the Morris Water Maze behavioral test. Microglia phagocytosis capacity was analyzed in vivo and by ex vivo and in vitro assays, and its activation by morphological changes (phalloidin staining) and expression of CD86, Mgl1, and TREM-2 by RT-qPCR. The mechanism triggered by the MpHE was characterized in microglia primary cultures and ex vivo assays by immunoblot (PPAR-γ) and RT-qPCR (CD36) and in vivo by flow cytometry, using GW9662 (PPAR-γ inhibitor) and pioglitazone (PPAR-γ agonist). The presence of bioactive compounds in the MpHE was determined by HPLC.

Results

MpHE efficiently reduced astrogliosis, the presence of insoluble Aβ peptides in the hippocampus and spatial learning impairments, of both, lean, and obese 5XFAD mice. This was accompanied by microglial cells accumulation around Aβ plaques in the cortex and the hippocampus and decreased expression of M1 inflammatory markers. Consistent with the fact that the MpHE rescued microglia phagocytic capacity via a PPAR-γ/CD36-dependent mechanism, the MpHE possess oleanolic acid and scopoletin as active phytochemicals.

Conclusions

M. parviflora suppresses neuroinflammation by inhibiting microglia pro-inflammatory M1 phenotype and promoting microglia phagocytosis. Therefore, M. parviflora phytochemicals represent an alternative to prevent cognitive impairment associated with a metabolic disorder as well as an effective prophylactic candidate for AD progression.

Electronic supplementary material

The online version of this article (10.1186/s12974-019-1515-3) contains supplementary material, which is available to authorized users.

Halophytic Grasses, a New Source of Nutraceuticals? A Review on Their Secondary Metabolites and Biological Activities

The Poaceae family, known as grasses, is distributed worldwide and is considered the most important group of monocotyledonous crops. Salt stress is multifactorial, therefore to survive, halophytes evolved a variety of adaptations, which include the biosynthesis of different primary and secondary metabolites. This trait enhances the accumulation of important families of compounds crucial to the prevention of a variety of chronic diseases. Besides, if proven edible, these species could cope with the increased soil salinity responsible for the decline of arable land due to their high nutritional/nutraceutical value. Herein, the phytochemical investigations performed in halophytes from the Poaceae family as well as their biological properties were explored. Among the 65 genera and 148 species of known halophytic grasses, only 14% of the taxa were studied phytochemically and 10% were subjected to biological evaluation. Notably, in the studied species, a variety of compound families, as well as bioactivities, were demonstrated, highlighting the potential of halophytic grasses.

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

This study was conducted to investigate protective effects of Urtica dioica extract on acetylcholinesterase (AChE) activity and the oxidative damage of brain tissues in scopolamine-induced memory impairment model. The rats were treated with (1) saline (control), (2) scopolamine, and (3-5) the plant extract (20, 50, or 100 mg/kg) before scopolamine. The traveled distance and the latency to find the platform in Morris water maze (MWM) by scopolamine-treated group were longer while the time spent in target quadrant was shorter than those of the control. Scopolamine decreased the latency to enter the dark in passive avoidance test. Besides, it also increased AChE activity and malondialdehyde (MDA) concentration in the hippocampal and cortical tissues while decreased thiols content and superoxide dismutase (SOD) and catalase (CAT) activities in the brain (p < 0.01-p <0.001). Treatment by the extract reversed all the effects of scopolamine (p < 0.05-p <0.001). According to the results of present study, the beneficial effects of U. dioica on memory can be attributed to its protective effects on oxidative damage of brain tissue and AChE activity.

Galantamine improves cognition, hippocampal inflammation, and synaptic plasticity impairments induced by lipopolysaccharide in mice

BACKGROUND

Neuroinflammation plays an important role in the onset and progression of neurodegenerative diseases such as Alzheimer's disease. Lipopolysaccharide (LPS, endotoxin) levels are higher in the brains of Alzheimer's disease patients and are associated with neuroinflammation and cognitive decline, while neural cholinergic signaling controls inflammation. This study aimed to examine the efficacy of galantamine, a clinically approved cholinergic agent, in alleviating LPS-induced neuroinflammation and cognitive decline as well as the associated mechanism.

METHODS

Mice were treated with galantamine (4 mg/kg, intraperitoneal injection) for 14 days prior to LPS exposure (intracerebroventricular injection). Cognitive tests were performed, including the Morris water maze and step-through tests. mRNA expression of the microglial marker (CD11b), astrocytic marker (GFAP), and pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) were examined in the hippocampus by quantitative RT-PCR. The inflammatory signaling molecule, nuclear factor-kappa B (NF-κB p65), and synapse-associated proteins (synaptophysin, SYN, and postsynaptic density protein 95, PSD-95) were examined in the hippocampus by western blotting. Furthermore, NF-κB p65 levels in microglial cells and hippocampal neurons were examined in response to LPS and galantamine.

RESULTS

Galantamine treatment prevented LPS-induced deficits in spatial learning and memory as well as memory acquisition of the passive avoidance response. Galantamine decreased the expression of microglia and astrocyte markers (CD11b and GFAP), pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α), and NF-κB p65 in the hippocampus of LPS-exposed mice. Furthermore, galantamine ameliorated LPS-induced loss of synapse-associated proteins (SYN and PSD-95) in the hippocampus. In the in vitro study, LPS increased NF-κB p65 levels in microglia (BV-2 cells); the supernatant of LPS-stimulated microglia (Mi-sup), but not LPS, decreased the viability of hippocampal neuronal cells (HT-22 cells) and increased NF-κB p65 levels as well as expression of pro-inflammatory cytokines (IL-1β, IL-6) in HT-22 cells. Importantly, galantamine reduced the inflammatory response not only in the BV-2 microglia cell line, but also in the HT-22 hippocampal neuronal cell line.

CONCLUSIONS

These findings indicate that galantamine could be a promising treatment to improve endotoxin-induced cognitive decline and neuroinflammation in neurodegenerative diseases.

Multi-targeted directed ligands for Alzheimer's disease: design of novel lead coumarin conjugates

Alzheimer's Disease (AD) is a neurodegenerative disease characterized by central nervous system insults with progressive cognitive (memory, attention) and non-cognitive (anxiety, depression) impairments. Pathophysiological events affect predominantly cholinergic neuronal loss and dysfunctions of the dopaminergic system. The aim of the current study was to design multi-targeted directed lead structures based on the coumarin scaffold with inhibitory properties at two key enzymes in disease relevant systems, i.e. acetylcholinesterase (AChE) and monoamine oxidase B (MAO-B). Conventional and microwave synthetic methods were utilized to synthesize coumarin scaffold-based novel morpholino, piperidino, thiophene and erucic acid conjugates. Biological assays indicated that the coumarin-morpholine ether conjugate BPR 10 was the most potent hMAO-B inhibitor. The coumarin-piperidine conjugates BPR 13 and BPR 12 were the most potent inhibitors of eeAChE at 100 μM and 1 μM, respectively. Molecular modelling studies were conducted with Accelrys^® Discovery Studio^® V3.1.1 utilising the published hMAO-B (2V61) and hAChE (4EY7) crystal structures. Compound BPR 10 occupies both the entrance and substrate cavities of the active site of MAO-B. BPR 13 resides in both the peripheral anionic site (PAS) and the catalytic anionic site (CAS) of hAChE. This study demonstrated that the coumarin scaffold serves as a promising pharmacophore for MTDLs design.

Distribution Assessments of Coumarins from Angelicae Pubescentis Radix in Rat Cerebrospinal Fluid and Brain by Liquid Chromatography Tandem Mass Spectrometry Analysis

Angelicae Pubescentis Radix (APR) is a widely-used traditional Chinese medicine. Pharmacological studies have begun to probe its biological activities on neurological disorders recently. To assess the brain penetration and distribution of APR, a validated ultra-performance liquid chromatography tandem mass spectrometry method was applied to the simultaneous determinations of the main coumarins from APR in the rat cerebrospinal fluid (CSF) and brain after oral administration of APR extract, including psoralen, xanthotoxin, bergapten, isoimperatorin, columbianetin, columbianetin acetate, columbianadin, oxypeucedanin hydrate, angelol B, osthole, meranzin hydrate and nodakenetin. Most of the tested coumarins entered the rat CSF and brain quickly, and double-peak phenomena in concentration-time curves were similar to those of their plasma pharmacokinetics. Columbianetin had the highest concentration in the CSF and brain, while psoralen and columbianetin acetate had the largest percent of CSF/plasma and brain/plasma, indicating that these three coumarins may be worthy of further research on the possible nervous effects. Correlations between the in vivo brain distributions and plasma pharmacokinetics of these coumarins were well verified. These results provided valuable information for the overall in vivo brain distribution characteristics of APR and also for its further studies on the active substances for the central nervous system.

Lycium Barbarum: A Traditional Chinese Herb and A Promising Anti-Aging Agent

Lycium barbarum has been used in China for more than 2,000 years as a traditional medicinal herb and food supplement. Lycium barbarum contains abundant Lycium barbarum polysaccharides (LBPs), betaine, phenolics, carotenoids (zeaxanthin and β-carotene), cerebroside, 2-O-β-d-glucopyranosyl-l-ascorbic acid (AA-2βG), β-sitosterol, flavonoids and vitamins (in particular, riboflavin, thiamine, and ascorbic acid). LBPs are the primary active components of Lycium barbarum. In this review, we discuss the pharmacological activities of LBPs and other major components. They have been reported to mediate significant anti-aging effects, through antioxidant, immunoregulative, anti-apoptotic activities and reducing DNA damage. Thus, the basic scientific evidence for anti-aging effects of LBPs is already available. However, additional studies are needed to understand mechanisms by which LBPs mediate anti-aging properties. Novel findings from such studies would likely pave the way for the clinical application of traditional chinese medicine Lycium barbarum in modern evidence-based medicine.

Neurotoxicity of fragrance compounds: A review

Fragrance compounds are chemicals belonging to one of several families, which are used frequently and globally in cosmetics, household products, foods and beverages. A complete list of such compounds is rarely found on the ingredients-list of such products, as "fragrance mixtures" are defined as "trade secrets" and thus protected by law. While some information regarding the general toxicity of some of these compounds is available, their neurotoxicity is known to a lesser extent. Here, we discuss the prevalence and neurotoxicity of fragrance compounds belonging to the three most common groups: phthalates, synthetic musks and chemical sensitizers.

Novel multitarget-directed tacrine derivatives as potential candidates for the treatment of Alzheimer's disease

Alzheimer’s disease (AD) is a neurodegenerative disorder, which is complex and progressive; it has not only threatened the health of elderly people, but also burdened the whole social medical and health system. The available therapy for AD is limited and the efficacy remains unsatisfactory. In view of the prevalence and expected increase in the incidence of AD, the design and development of efficacious and safe anti-AD agents has become a hotspot in the field of pharmaceutical research. Due to the multifactorial etiology of AD, the multitarget-directed ligands (MTDLs) approach is promising in search for new drugs for AD. Tacrine, which is the first acetylcholinesterase (AChE) inhibitor, has been selected as the ideal active fragment because of its simple structure, clear activity, and its superiority in the structural modification, thus it could be introduced into the overall molecular skeletons of the multi-target-directed anti-AD agents. In this review, we have summarized the recent advances (2012 to the present) in the chemical modification of tacrine, which could provide the reference for the further study of novel multi-target-directed tacrine derivatives to treat AD.

Urtica dioica leaves modulates hippocampal smoothened-glioma associated oncogene-1 pathway and cognitive dysfunction in chronically stressed mice

The present study was aimed to evaluate the effect of Urtica dioica (UD) extract against chronic unpredictable stress (CUS)-induced associative memory dysfunction and attempted to explore the possible mechanism. Male Swiss albino mice (25-30g) were divided into six groups, viz. group-I received 0.3% carboxymethyl cellulose and served as control (CTRL), group II was exposed to CUS (21days) and received vehicle (CUS), group III was subjected to CUS and received Hypericum perforatum extract (350mg/kg, p.o.) (CUS+HYP), group IV received Hypericum perforatum extract (350mg/kg, p.o.) (CTRL+HYP); group V was subjected to CUS and received UD extract (50mg/kg, p.o.) (CUS+UD), group VI received UD extract (50mg/kg, p.o.) (CTRL+UD). CUS significantly induced body weight loss (p<0.05) and associative memory impairment in step down task (p<0.05) as compared to control mice. CUS significantly downregulated Smo (p<0.05), Gli1 (p<0.01), cyclin D1 (p<0.05), BDNF (p<0.01), TrKB (p<0.01) and MAPK1 (p<0.01) mRNA expression in hippocampus as compared to control mice. CUS significantly increased the levels of TBARS (p<0.01) and nitric oxide (p<0.001), and decreased catalase (p<0.001) and total thiol (p<0.01) in plasma resulting in oxidative stress and inflammation. Chronic UD administration significantly reverted CUS mediated body weight loss (p<0.05) and cognitive impairment (p<0.05). UD administration significantly decreased the levels of TBARS (p<0.01) and nitric oxide (p<0.05), and increased the levels of catalase (p<0.01) and total thiol (p<0.05) in plasma. Chronic UD administration significantly upregulated hippocampal Smo (p<0.05), Gli1 (p<0.001), cyclin D1 (p<0.05), BDNF (p<0.05), TrKB (p<0.05) and MAPK1 (p<0.05) in stressed mice. Further, UD extract did not reverse cyclopamine induced downregulation of Gli1 and Ptch1 mRNA in hippocampal slices. UD modulated Smo-Gli1 pathway in the hippocampus as well as exerted anti-inflammatory and antioxidant effects. UD extract might prove to be effective for stress mediated neurological disorders.

Biological importance of structurally diversified chromenes

Compounds incorporating the chromene scaffold are largely present in natural products and display a wide variety of biological activities. Their low toxicity combined to the broad pharmacological properties have inspired medicinal chemists in the search for new therapeutic agents. This review covers the literature between 1993 and on the biological activity of 2H- and 4H-chromenes, both from natural and synthetic origin. Includes a section that identifies a selection of chromene-based natural products, followed by recent literature on bioactive natural chromenes and the corresponding source, covering plants and fruits. Synthetic chromenes are equally important and a separate section addresses the use of these derivatives as new leads for drug discovery. Different biological targets were identified, namely those associated with anticancer, antimicrobial, anti-inflammatory, antithrombotic and antipsychotic activities.

Urtica dioica modulates hippocampal insulin signaling and recognition memory deficit in streptozotocin induced diabetic mice

Diabetes mellitus has been associated with functional abnormalities in the hippocampus and performance of cognitive function. Urtica dioica (UD) has been used in the treatment of diabetes. In our previous report we observed that UD extract attenuate diabetes mediated associative and spatial memory dysfunction. The present study aimed to evaluate the effect of UD extract on mouse model of diabetes-induced recognition memory deficit and explore the possible mechanism behind it. Streptozotocin (STZ) (50 mg/kg, i.p. consecutively for 5 days) was used to induce diabetes followed by UD extract (50 mg/kg, oral) or rosiglitazone (ROSI) (5 mg/kg, oral) administration for 8 weeks. STZ induced diabetic mice showed significant decrease in hippocampal insulin signaling and translocation of glucose transporter type 4 (GLUT4) to neuronal membrane resulting in cognitive dysfunction and hypolocomotion. UD treatment effectively improved hippocampal insulin signaling, glucose tolerance and recognition memory performance in diabetic mice, which was comparable to ROSI. Further, diabetes mediated oxidative stress and inflammation was reversed by chronic UD or ROSI administration. UD leaves extract acts via insulin signaling pathway and might prove to be effective for the diabetes mediated central nervous system complications.

The genus Sida L. - A traditional medicine: Its ethnopharmacological, phytochemical and pharmacological data for commercial exploitation in herbal drugs industry

ETHNOPHARMACOLOGICAL RELEVANCE

Sida L. (Malvaceae) has been used for centuries in traditional medicines in different countries for the prevention and treatment of different diseases such as diarrhea, dysentery, gastrointestinal and urinary infections, malarial and other fevers, childbirth and miscarriage problems, skin ailments, cardiac and neural problems, asthma, bronchitis and other respiratory problems, weight loss aid, rheumatic and other inflammations, tuberculosis, etc.

AIMS OF THIS REVIEW

To assess the scientific evidence for therapeutic potential of Sida L. and to identify the gaps of future research needs.

METHODS

The available information on the ethnomedicinal uses, phytochemistry, pharmacology and toxicology of Sida species was collected via a library and electronic searches in SciFinder, PubMed, ScienceDirect, Google Scholar for the period, 1933-2015.

RESULTS

A variety of ethnomedicinal uses of Sida species have been found in India, China, Afrian and American countries. Phytochemical investigation of this genus has resulted in identification of about 142 chemical constituents, among which alkaloids, flavonoids and ecdysteroids are the predominant groups. The crude extracts and isolates have exhibited a wide spectrum of in vitro and in vivo pharmacological effects involving antimicrobial, analgesic, anti-inflammatory, abortifacient, neuroprotective, cardiovascular and cardioprotective, antimalarial, antitubercular, antidiabetic and antiobesity, antioxidant and nephroprotective activities among others. Ethnopharmacological preparations containing Sida species as an ingredient in India, African and American countries possess good efficacy in health disorders. From the toxicity perspective, only three Sida species have been assessed and found safe for oral use in rats.

CONCLUSIONS

Pharmacological results supported some of the uses of Sida species in the traditional medicine. Alkaloids, flavonoids, other phenolics and ecdysteroids were perhaps responsible for the activities of extracts of the plants of this genus. No clinical study was reported. The detailed study on mechanism of action of isolates and extracts and their clinical study are needed for their use in modern medicine. More attention should be paid to Sida acuta, Sida cordifolia, Sida spinosa, Sida rhombifolia and Sida veronicaefolia in the domain of diarrhea, dysentery, gastrointestinal and urinary infections, skin ailments, asthma, bronchitis and other respiratory problems, malaria, childbirth and miscarriage problems, cardiac and neural problems, weight loss aid, and rheumatic and other inflammations, etc. Furthermore, detailed study on quality and safety assurance data on available ethnopharmacological preparations is needed for their commercial exploitation in local and global markets.

Implication of coumarins towards central nervous system disorders

Coumarins are widely distributed, plant-derived, 2H-1-benzopyran-2-one derivatives which have attracted intense interest in recent years as a result of their diverse and potent pharmacological properties. Particularly, their effects on the central nervous system (CNS) have been established. The present review discusses the most important pharmacological effects of natural and synthetic coumarins on the CNS, including their interactions with benzodiazepine receptors, their dopaminergic and serotonergic affinity, and their ability to inhibit cholinesterases and monoamine oxidases. The structure-activity relationships pertaining to these effects are also discussed. This review posits that natural or synthetic coumarins have the potential for development in the therapy of psychiatric and neurodegenerative disorders, including Alzheimer's and Parkinson's diseases, schizophrenia, anxiety, epilepsy, and depression.

Coumarin: A Privileged Scaffold for the Design and Development of Antineurodegenerative Agents

Drug development for neurodegenerative diseases (NDs) is foremost task for the medicinal chemists in the 21st century. Coumarins are exemplary of an assorted and aptitudinally useful set of drugs. Coumarins play a momentous role in several pharmacological and medicinal aspects. Its analogues are anticipated to play a significant role in the development of new therapeutic leads for NDs. Their promising applications in the field of ND medication are exemplified by clinical candidates such as nodakenin that have been potent for demoting memory impairment. Apart from ND, clinically used anticoagulant warfarin, anticoagulant dicoumarol, and antibiotic coumermycin, novobiocin and chartesium grab the interest of researchers in coumarins. It would be worthwhile to look at the different biological processes that could cause neurodegeneration, thereby establishing a link with distinct coumarin derivatives to serve the purpose of medication. This review undertakes estimation of the wide spectrum of studies focusing coumarin to the domain of drug research for ND. Herein, we search for multitarget coumarin-based inhibitors and their scope for NDs. Future challenges in coumarin-based drug development have been discussed, and emphases have been laid on the future perspectives of coumarins as possible drugs in the future for the treatment of NDs.

Transport of Twelve Coumarins from Angelicae Pubescentis Radix across a MDCK-pHaMDR Cell Monolayer-An in Vitro Model for Blood-Brain Barrier Permeability

Angelicae Pubescentis Radix (APR), a widely used traditional Chinese medicine, is reported to have central nervous system activities. The purpose of this study was to characterize the blood-brain barrier permeability of twelve coumarins from APR including umbelliferone (1), osthol (2), scopoletin (3), peucedanol (4), ulopterol (5), angepubebisin (6), psoralen (7), xanthotoxin (8), bergapten (9), isoimperatorin (10), columbianadin (11), and columbianetin acetate (12) with an in vitro model using a MDCK-pHaMDR cell monolayer. The cell monolayer was validated to be suitable for the permeation experiments. The samples’ transports were analyzed by high performance liquid chromatography and their apparent permeability coefficients (P_app) were calculated. According to the P_app value, most coumarins could be characterized as well-absorbed compounds except for 4, 10 and 11 which were moderately absorbed ones, in concentration-dependent and time-dependent manners. The results of P-glycoprotein (P-gp) inhibitor (verapamil) experiments showed that the transport of coumarin 4 was affected by the transport protein P-gp. Sigmoid functions between permeability log(P_{app AP-BL}*MW^0.5) and log D (at pH 7.4) were established to analyze the structure-activity relationship of coumarins. The results provide useful information for discovering the substance basis for the central nervous system activities of APR, and predicting the permeability of other coumarins through BBB.

Striatal dopamine release regulation by the cholinergic properties of the smokeless tobacco, gutkha

Tobacco products influence striatal dopamine (DA) release primarily through the actions of nicotine, an agonist of nicotinic acetylcholine receptors (nAChR). Gutkha is a smokeless tobacco product that contains not only nicotine, but also includes the habit-forming areca nut and other plant-based constituents that contribute muscarinic acetylcholine receptor (mAChR) agonists and other cholinergic agents. Thus, the net influence of the cholinergic agents in gutkha on striatal DA release is difficult to predict. This study investigated the influence of gutkha extract on evoked DA release in mouse striatal slices using fast-scan cyclic voltammetry. The potency of a given concentration of nicotine in the gutkha extract was found to be significantly lower than that of a comparable concentration of nicotine alone. Atropine, a mAChR antagonist, increased the potency of gutkha-associated nicotine; however, other experiments suggested that this was mediated in part by direct effects of atropine at nAChRs. Overall, these results suggest that the unique constituents of gutkha work together to oppose the influence of gutkha-associated nicotine on evoked striatal DA release.

Urtica dioica leaves modulates muscarinic cholinergic system in the hippocampus of streptozotocin-induced diabetic mice

Diabetes mellitus is a chronic metabolic disorder and has been associated with cognitive dysfunction. In our earlier study, chronic Urtica dioica (UD) treatment significantly ameliorated diabetes induced associative and spatial memory deficit in mice. The present study was designed to explore the effect of UD leaves extract on muscarinic cholinergic system, which has long been known to be involved in cognition. Streptozotocin (STZ) (50 mg/kg, i.p., consecutively for 5 days) was used to induce diabetes followed by treatment with UD extract (50 mg/kg, oral) or rosiglitazone (5 mg/kg, oral) for 8 weeks. STZ-induced diabetic mice showed significant reduction in hippocampal muscarinic acetylcholine receptor-1 and choline acetyltransferase expressions. Chronic diabetes significantly up-regulated the protein expression of acetylcholinesterase associated with oxidative stress in hippocampus. Besides, STZ-induced diabetic mice showed hypolocomotion with up-regulation of muscarinic acetylcholine receptor-4 expression in striatum. Chronic UD treatment significantly attenuated the cholinergic dysfunction and oxidative stress in the hippocampus of diabetic mice. UD had no effect on locomotor activity and muscarinic acetylcholine receptor-4 expression in striatum. In conclusion, UD leaves extract has potential to reverse diabetes mediated alteration in muscarinic cholinergic system in hippocampus and thereby improve memory functions.

Urtica dioica extract attenuates depressive like behavior and associative memory dysfunction in dexamethasone induced diabetic mice

Evidences suggest that glucocorticoids results in depression and is a risk factor for type 2 diabetes. Further diabetes induces oxidative stress and hippocampal dysfunction resulting in cognitive decline. Traditionally Urtica dioica has been used for diabetes mellitus and cognitive dysfunction. The present study investigated the effect of the hydroalcoholic extract of Urtica dioica leaves (50 and 100 mg/kg, p.o.) in dexamethasone (1 mg/kg, i.m.) induced diabetes and its associated complications such as depressive like behavior and cognitive dysfunction. We observed that mice administered with chronic dexamethasone resulted in hypercortisolemia, oxidative stress, depressive like behavior, cognitive impairment, hyperglycemia with reduced body weight, increased water intake and decreased hippocampal glucose transporter-4 (GLUT4) mRNA expression. Urtica dioica significantly reduced hyperglycemia, plasma corticosterone, oxidative stress and depressive like behavior as well as improved associative memory and hippocampal GLUT4 mRNA expression comparable to rosiglitazone (5 mg/kg, p.o.). Further, Urtica dioica insignificantly improved spatial memory and serum insulin. In conclusion, Urtica dioica reversed dexamethasone induced hyperglycemia and its associated complications such as depressive like behavior and cognitive dysfunction.

Ameliorative effect of Noni fruit extract on streptozotocin-induced memory impairment in mice

This study evaluated the effects of a standardized ethyl acetate extract of Morinda citrifolia L. (Noni) fruit on impairment of memory, brain energy metabolism, and cholinergic function in intracerebral streptozotocin (STZ)-treated mice. STZ (0.5 mg/kg) was administered twice at an interval of 48 h. Noni (50 and 100 mg/kg, postoperatively) was administered for 21 days following STZ administration. Memory function was evaluated using Morris Water Maze and passive avoidance tests, and brain levels of cholinergic function, oxidative stress, energy metabolism, and brain-derived neurotrophic factor (BDNF) were estimated. STZ caused memory impairment in Morris Water Maze and passive avoidance tests along with reduced brain levels of ATP, BDNF, and acetylcholine and increased acetylcholinesterase activity and oxidative stress. Treatment with Noni extract (100 mg/kg) prevented the STZ-induced memory impairment in both behavioral tests along with reduced oxidative stress and acetylcholinesterase activity, and increased brain levels of BDNF, acetylcholine, and ATP level. The study shows the beneficial effects of Noni fruit against STZ-induced memory impairment, which may be attributed to improved brain energy metabolism, cholinergic neurotransmission, BDNF, and antioxidative action.

Role of Acorus calamus and alpha-asarone on hippocampal dependent memory in noise stress exposed rats

Stress is a condition or stimulus that threatens an organism's survival. Noise is an environmental stressor. It is well known that long term as well as acute exposure to noise led to oxidative stress. In the present study, it was investigated that the persistence of noise stress (100 dBA/4 h/d for 30 days) could cause memory impairment in rats and whether ethylacetate extract of AC EAAC (50 mg kg(-1) b.wt.) and alpha-Asarone (9 mg kg(-1) b.wt.). treatment can prevent or not. In order to understand the possible mechanism behind it, antioxidant status and acetylcholinesterase (AChE) activity in hippocampus was evaluated after rats were tested in Radial Eight-arm Maze (RAM). Heat shock protein 70 (hsp 70) expression in hippocampus was also evaluated to understand the intensity of stress level. Results showed that after noise stress exposure, time taken to visit all the baited arms, working and reference memory errors were increased in RAM. The superoxide dismutase, lipid peroxidation, AChE activity, hsp 70 were significantly increased with concomitant decrease in catalase, glutathione peroxidase activity and G6PD activity of non-enzymatic levels was observed in the 30 days noise stress exposed group. When rats were co-administrated with EAAC and alpha-Asarone prevents the noise stress induced alterations significantly. In Conclusion, noise stress induced oxidative stress, increased AChE activity, and over expression of hsp 70 in hippocampus region might have led to the impairment of spatial memory. EAAC and alpha-Asarone prevents this noise stress induced memory impairment.

Impairment of novel object recognition in adulthood after neonatal exposure to diazinon

Diazinon is an organophosphate pesticide that is still heavily used in agriculture, home gardening, and indoor pest control in Japan. The present study investigated the effect of neonatal exposure to diazinon on hippocampus-dependent novel object recognition test performance and the expression of the N-methyl-D-aspartate (NMDA) receptor and its signal transduction pathway-related genes in the hippocampi of young adult and adult mice. Male offspring of C3H/HeN mice were subcutaneously treated with 0, 0.5, or 5 mg/kg of diazinon for 4 consecutive days beginning on postnatal day (PND) 8. Beginning on PND 46 or PND 81, a novel object recognition test was performed on 4 consecutive days. The hippocampi were collected on PND 50 or PND 85 after the completion of the novel object recognition test, and the expression levels of neurotrophins and the NMDA receptor and its signal transduction pathway-related genes were examined using real-time RT-PCR. Diazinon-injected mice exhibited a poor ability to discriminate between novel and familiar objects during both the PND 49 and the PND 84 tests. The NMDA receptor subunits NR1 and NR2B and the related protein kinase calcium/calmodulin-dependent protein kinase (CaMK)-IV and the transcription factor cyclic AMP responsive element binding protein (CREB)-1 mRNA levels were reduced in the PND 50 mice. However, no significant changes in the expressions of the NMDA subunits and their signal transduction molecules were observed in the hippocampi of the PND 85 mice. The expression level of nerve growth factor mRNA was significantly reduced in the PND 50 or 85 mice. These results indicate that neonatal diazinon exposure impaired the hippocampus-dependent novel object recognition ability, accompanied by a modulation in the expressions of the NMDA receptor and neurotrophin in young adult and adult mice.