Swertisin, a C-glucosylflavone, ameliorates scopolamine-induced memory impairment in mice with its adenosine A1 receptor antagonistic property

Effects of aerobic exercise and dietary flavonoids on cognition: a systematic review and meta-analysis

Introduction: Studies have shown that exercise increases angiogenesis and perfusion in the hippocampus, activates neurogenesis in the dentate gyrus and increases synaptic plasticity, as well as increases the complexity and number of dendritic spines, all of which promote memory function and protect against cognitive decline. Flavonoids are gaining attention as antioxidants in health promotion due to their rich phenolic content, particularly for their modulating role in the treatment of neurodegenerative diseases. Despite this, there has been no comprehensive review of cognitive improvement supplemented with flavonoid and prescribed with exercise or a combination of the two interventions has been conducted. The purpose of this review is to determine whether a combined intervention produces better results when given together than when given separately. Methods: Relevant articles assessing the effect of physical exercise, flavonoid or in combination on cognitive related biomarkers and neurobehavioral assessments within the timeline of January 2011 until June 2023 were searched using three databases; PubMed, PROQUEST and SCOPUS. Results: A total of 705 articles were retrieved and screened, resulting in 108 studies which are in line with the objective of the current study were included in the analysis. Discussion: The selected studies have shown significant desired effect on the chosen biomarkers and neurobehavioral assessments. Systematic Review Registration: identifier: [CRD42021271001].

Potential Anti-Amnesic Activity of a Novel Multimodal Derivative of Salicylamide, JJGW08, in Mice

Memory impairments constitute a significant problem worldwide, and the COVID-19 pandemic dramatically increased the prevalence of cognitive deficits. Patients with cognitive deficits, specifically memory disturbances, have underlying comorbid conditions such as schizophrenia, anxiety, or depression. Moreover, the available treatment options have unsatisfactory effectiveness. Therefore, there is a need to search for novel procognitive and anti-amnesic drugs with additional pharmacological activity. One of the important therapeutic targets involved in the modulation of learning and memory processes are serotonin receptors, including 5-HT1A, 5-HT6, and 5-HT7, which also play a role in the pathophysiology of depression. Therefore, this study aimed to assess the anti-amnesic and antidepressant-like potential of JJGW08, a novel arylpiperazine alkyl derivative of salicylamide with strong antagonistic properties at 5-HT1A and D2 receptors and weak at 5-HT2A and 5-HT7 receptors in rodents. First, we investigated the compound’s affinity for 5-HT6 receptors using the radioligand assays. Next, we assessed the influence of the compound on long-term emotional and recognition memory. Further, we evaluated whether the compound could protect against MK-801-induced cognitive impairments. Finally, we determined the potential antidepressant-like activity of the tested compound. We found that JJGW08 possessed no affinity for 5-HT6 receptors. Furthermore, JJGW08 protected mice against MK-801-induced recognition and emotional memory deficits but showed no antidepressant-like effects in rodents. Therefore, our preliminary study may suggest that blocking serotonin receptors, especially 5-HT1A and 5-HT7, might be beneficial in treating cognitive impairments, but it requires further investigation.

Novel Multimodal Salicylamide Derivative with Antidepressant-like, Anxiolytic-like, Antipsychotic-like, and Anti-Amnesic Activity in Mice

Depression, anxiety, and schizophrenia may coexist in psychiatric patients. Moreover, these disorders are very often associated with cognitive impairments. However, pharmacotherapy of these conditions remains challenging due to limited drug effectiveness or numerous side effects. Therefore, there is an urgent need to develop novel multimodal compounds that can be used to treat depression, anxiety, and schizophrenia, as well as memory deficits. Thus, this study aimed to evaluate the potential antidepressant-like, anxiolytic-like, antipsychotic-like effects, and anti-amnesic properties, of the novel arylpiperazine derivative of salicylamide, JJGW07, with an affinity towards serotonin 5-HT1A, 5-HT2A, and 5-HT7 and dopamine D2 receptors. Firstly, we investigated the compound's affinity for 5-HT6 receptors and its functional activity by using in vitro assays. JJGW07 did not bind to 5-HT6 receptors and showed antagonistic properties for 5-HT1A, 5-HT2A, 5-HT7, and D2 receptors. Based on the receptor profile, we performed behavioral studies in mice to evaluate the antidepressant-like, anxiolytic-like, and antipsychotic-like activity of the tested compound using forced swim and tail suspension tests; four-plate, marble-burying, and elevated plus maze tests; and MK-801- and amphetamine-induced hyperlocomotion tests, respectively. JJGW07 revealed antidepressant-like properties in the tail suspension test, anxiolytic-like effects in the four-plate and marble-burying tests, and antipsychotic-like activity in the MK-801-induced hyperlocomotion test. Importantly, the tested compound did not induce catalepsy and motor impairments or influence locomotor activity in rodents. Finally, to assess the potential procognitive and anti-amnesic properties of JJGW07, we used passive avoidance and object recognition tests in mice. JJGW07 demonstrated positive effects on long-term emotional memory and also ameliorated MK-801-induced emotional memory impairments in mice, but showed no procognitive properties in the case of recognition memory. Our results encourage the search for new compounds among salicylamide derivatives, which could be model structures with multitarget mechanisms of action that could be used in psychiatric disorder therapy.

Zizyphi Spinosae Semen: a natural herb resource for treating neurological disorders

Neurological disorders generally have the characteristics of occult onset and progressive development, which can do some serious damage to human body in the aging process. It is worth noting that traditional medicine can potentially prevent and treat such diseases. Zizyphi Spinosae Semen (ZSS), the seeds of Ziziphus jujuba var. spinosa it has a long clinical history for sleep regulation. In recent years, ZSS has been proved to exhibit various types of neuroprotective activity, such as sleep improvement, antidepressant, anti-anxiety, memory improvement and etc. It has become a popular natural product due to its many inherently available compounds that demonstrate medicinal and pharmacological importance. This paper reviews the main components and their metabolic transformation processes, highlights the various neurofunctional regulation activities and their mechanisms of ZSS, providing a theoretical basis for further research and clinical application of this natural medicine.

Study on the Antianxiety Mechanism of Suanzaoren Decoction Based on Network Pharmacology and Molecular Docking

Objective. Suanzaoren Decoction (SZRT) is a classic decoction to calm the nerves in traditional Chinese medicine (TCM). It has been extensively treated as an antianxiety drug in modern times, but the material basis and pharmacological mechanisms are still unclear. To explore the material basis and corresponding potential targets, as well as to elucidate the mechanism of SZRT, network pharmacology and molecular docking methods were utilized. Methods. The main chemical compounds and potential targets of SZRT were collected from the pharmacological database analysis platform (TCMSP). Anxiety targets were obtained from the GeneCards database. Then, a target compound network was established using overlapping genes and the corresponding potential compounds. Protein interaction analysis, GO enrichment, and KEGG pathway enrichment were performed using the STRING database, DAVID database, and KOBAS database. Finally, molecular docking was conducted between MAOB and its corresponding active compound in SZRT to further verify the results. Results. A total of 137 active components in SZRT were screened from the TCMSP database, and 210 corresponding targets were predicted. A total of 5434 anxiety-related targets were obtained from the disease target database, and finally 22 potential targets of SZRT on antianxiety were obtained. The constructed C-T network showed that the average degree of active components was 5.4, and four of them interacted with six or more targets. PPI analysis shows that key genes such as MAOA, MAOB, IL1B, TNF, NR3CI, and HTR3A were identified as potential therapeutic targets. A pathway analysis showed that SZRT may participate in neurotransmitter regulation and immunoregulation in a synergistic way to treat anxiety. The binding energy between the active compounds and MAOB was low, indicating good binding. The results of molecular docking showed that all the 10 active ingredients were able to successfully dock with MAOB, and the binding energy of coumaroyltyramine with MAOB was the lowest, that is, −9.6 kcal/mol, and the binding method was hydrogen bonding. Conclusions. SZRT produces antianxiety effects mainly by affecting the neurotransmitter release, transmission, and immunoregulation. This study provides a new approach to elucidating the molecular mechanism and material basis of SZRT in the treatment of anxiety, and it will also benefit the application of TCM in modern medicine.

Swertisin, a novel SGLT2 inhibitor, with improved glucose homeostasis for effective diabetes therapy

Failing pancreas and subsequent loss of pancreatic β cells worsen diabetic conditions which are further alleviated by the mounting up of glucose levels. Inhibition of sodium glucose cotransporter 2 (SGLT2) in the kidney responsible for glucose reabsorption strikingly reduces blood glucose levels. Bioactive swertisin showed a promising glucose-lowering effect. Hence, we aimed to mechanistically dissect the glucose lowering property of swertisin. A systematic in silico, in vitro, and in vivo approach was directed for target analysis of swertisin. Molecular docking was performed with Swertisn-hSGLT2 complex. Glucose uptake assay and protein expression for SGLT2 and regulatory proteins were performed under swertisin effect. Various physiological and metabolic parameters were evaluated in STZ induced BALB/c mice using swertisin treatment. SGLT2 expression was evaluated in the kidney tissue of mice. Swertisn-hSGLT2 molecularly docked complex showed similar binding energy compared to the Canagliflozin-hSGLT2 complex. Swertisin inhibited glucose uptake and decreased expression of SGLT2 in HEK293 cells. Swertisin does not affect GLUT mediated glucose transport. Swertisin treated diabetic mice demonstrated remarkable improvement in overall glucose homeostasis. Reduced expression of SGLT2 was found in kidney tissue along with reduced PKC expression which is one of the key regulators of SGLT2. Our study explored SGLT2 as a selective target of swertisin for its swift glucose-lowering action which not only inhibits SGLT2 but also reduces its expression in diabetic condition. Thus, the potential property of swertisin as a glucose-lowering agent is remarkable which points towards the likelihood of a wider avenue of diabetes therapy.

Exploration of chalcones and related heterocycle compounds as ligands of adenosine receptors: therapeutics development

Adenosine receptors (ARs) are ubiquitously distributed throughout the mammalian body where they are involved in an extensive list of physiological and pathological processes that scientists have only begun to decipher. Resultantly, AR agonists and antagonists have been the focus of multiple drug design and development programmes within the past few decades. Considered to be a privileged scaffold in medicinal chemistry, the chalcone framework has attracted a substantial amount of interest in this regard. Due to the potential liabilities associated with its structure, however, it has become necessary to explore other potentially promising compounds, such as heterocycles, which have successfully been obtained from chalcone precursors in the past. This review aims to summarise the emerging therapeutic importance of adenosine receptors and their ligands, especially in the central nervous system (CNS), while highlighting chalcone and heterocyclic derivatives as promising AR ligand lead compounds.

Potential of Caffeine in Alzheimer's Disease-A Review of Experimental Studies

Alzheimer's disease (AD) is the most common type of dementia leading to progressive memory loss and cognitive impairment. Considering that pharmacological treatment options for AD are few and not satisfactory, increasing attention is being paid to dietary components that may affect the development of the disease. Such a dietary component may be caffeine contained in coffee, tea or energy drinks. Although epidemiological data suggest that caffeine intake may counteract the development of cognitive impairment, results of those studies are not conclusive. The aim of the present study is to review the existing experimental studies on the efficacy of caffeine against AD and AD-related cognitive impairment, focusing on the proposed protective mechanisms of action. In conclusion, the reports of studies on experimental AD models generally supported the notion that caffeine may exert some beneficial effects in AD. However, further studies are necessary to elucidate the role of caffeine in the effects of its sources on cognition and possibly AD risk.

Phytochemistry and Biological Activities of Iris Species Growing in Iraqi Kurdistan and Phenolic Constituents of the Traditional Plant Iris postii

A dozen Iris species (Iridaceae) are considered traditional remedies in Kurdistan, especially for treating inflammations. Phytochemical studies are still scarce. The information reported in the literature about Iris species growing in Kurdistan has been summarized in the first part of this paper, although, except for Iris persica, investigations have been performed on vegetal samples collected in countries different from Kurdistan. In the second part of the work, we have investigated, for the first time, the contents of the methanolic extracts of Iris postii aerial parts and rhizomes that were collected in Kurdistan. Both extracts exhibited a significant dose-dependent free radical scavenging and total antioxidant activities, comparable to those of ascorbic acid. Medium-pressure liquid chromatographic separations of the two extracts afforded l-tryptophan, androsin, isovitexin, swertisin, and 2″-O-α-l-rhamnopyranosyl swertisin from the aerial parts, whereas ε-viniferin, trans-resveratrol 3,4′-O-di-β-d-glucopyranoside, and isotectorigenin were isolated from the rhizomes. This is the first finding of the last three metabolites from an Iris species. The various remarkable biological activities of isolated compounds scientifically sustain the traditional use of I. postii as a medicinal plant.

Anti-hepatitis B virus activity of swertisin isolated from Iris tectorum Maxim

ETHNOPHARMACOLOGICAL RELEVANCE

Iris tectorum Maxim (I. tectorum, Yuan Wei in Chinese) is a common and traditional Chinese medicinal herb that be used to treat liver-related diseases. However, the anti-HBV activity of I. tectorum and its isolates has not been systemically studied.

AIM OF THE STUDY

To screen the active part of I. tectorum and systemically evaluate their anti-HBV activity.

MATERIALS AND METHODS

In this study, a series of compounds from I. tectorum were evaluated for their ability to inhibit HBV replication. Swertisin showed a significant inhibitory function on HBV replication. Then, the suppression effect of different concentrations of swertisin in HBsAg, HBeAg and HBV DNA level in HepG2.2.15 cells and HBV-infected HepG2-NTCP cells were comprehensive evaluated, respectively. Moreover, the anti-HBV effects of swertisin were confirmed in HBV transgenic mice model.

RESULTS

Among these compounds, swertisin strongly inhibited the HBsAg, HBeAg and HBV DNA level in a dose-dependent manner in HepG2.2.15 cells and HBV-infected HepG2-NTCP cells. Furthermore, swertisin showed a significant inhibition role on HBV replication in HBV transgenic mice model, the inhibition effect of which was enhanced when combined with ETV.

CONCLUSIONS

We have identified that swertisin can inhibit HBeAg and HBsAg production, as well as HBV DNA in vitro and in vivo. This study show that we may found a novel compound isolated from traditional Chinese medicines with potent anti-HBV function.

Ameliorative effect of deoxyvasicine on scopolamine-induced cognitive dysfunction by restoration of cholinergic function in mice

BACKGROUND

Aerial parts of Peganum harmala Linn is used as a traditional medical herb for treatment of amnesia in Uighur medicine in China. Deoxyvasicine (DVAS) is one of the chief active ingredients in P. harmala, it possesses strong acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities in vitro, but the therapeutic effect and mechanisms on amnesia in vivo are unclear.

PURPOSE

The objective of this study was to investigate the improvement effect of DVAS from P. harmala in learning and memory deficits of scopolamine-induced mice and elucidate the underlying mechanisms involved.

METHODS

Mice were pretreated with DVAS (5, 15 and 45 mg/kg) and huperzine-A (0.2 mg/kg) by gavage for 7 days, and subsequently were daily intraperitoneally injected with scopolamine (1 mg/kg) to induce learning and memory deficits and behavioral performance was assessed by Morris water maze. To further evaluate the potential mechanisms of DVAS in improving learning and memory capabilities, pathological change, levels of various biochemical markers and protein expressions related to cholinergic system, oxidative stress, and neuroinflammation were examined.

RESULTS

The results showed that DVAS could alleviate learning and memory deficits in scopolamine-treated mice. DVAS could regulate cholinergic function by inhibiting AChE and activating choline acetyltransferase (ChAT) activities and protein expressions. DVAS could induce brain-derived neurotrophic factor and protect hippocampal pyramidal cells against neuronal damage. DVAS also enhanced antioxidant defense via increasing the antioxidant enzyme level and activity of glutathione peroxidase, and anti-inflammatory function through suppressing tumor necrosis factor-α. Additionally, DVAS could regulate the neurotransmitters by elevating acetylcholine, 5-hydroxytryptamine, γ-aminobutyric acid and reducing 5-hydroxyindole-3-acetic acid and glutamic acid.

CONCLUSION

Results illustrated that DVAS may be a promising candidate compound against amnesia via restoration of cholinergic function, regulating neurotransmitters, attenuating neuroinflammation and oxidative stress.

Comparison of the Quenching Effects of Two Main Components of Ziziphi Spinosae Semen on Serum Albumin Fluorescence

Swertisin (6-glucosyl flavonoid) and spinosin (2″-β-O-glucopyranosyl swertisin) are two main components from Ziziphi Spinosae Semen, with anti-anxiety and hypnosis effects. The paper aims to compare the differences between the two compounds binding with serum albumins (BSA and HSA). Swertisin and spinosin statically quench intrinsic fluorescence of serum proteins by binding to proteins to form complexes. The fluorescence quenching rates of BSA induced by swertisin or spinosin are faster than those of HSA resulted by swertisin or spinosin, respectively. Each serum protein has only one binding site respectively accessible to the two compounds. Hydrophobic force and hydrogen bond play the important roles during the biding process of swertisin with proteins, but van der Waals force and hydrogen bond are major driving forces for spinosin binding to proteins. Synchronous fluorescence data show that spinosin binds to BSA and HSA and thus changes Tyr and Trp residue microenvironments, and has a greater effect on the latter. Compared with swertisin, spinosin has a stronger effect on the α-helix of proteins. But the distance between swertisin and proteins is slightly closer than spinosin. These findings will contribute to further understand the reaction of Ziziphi Spinosae Semen in the liver phase I oxidation, intestinal hydrolysis and deparaffin metabolism.

Isoorientin improves scopolamine-induced cognitive impairments by restoring the cholinergic system, antioxidant defense, and p-CREB/BDNF signaling in the hippocampus and frontal cortex

Isoorientin (ISO) is considered one of the most important flavonoids with various pharmacological effects such as antioxidant, anti-inflammatory, and anti-cancer activities. Despite these beneficial activities, the effects of ISO on learning and memory have not been investigated so far. The current study evaluated the memory-enhancing effects of ISO in a scopolamine-treated mouse model by using the Y-maze and passive avoidance tests. The results showed that ISO (5 and 10 mg/kg, p.o.) treatment significantly improved the cognitive impairments caused by scopolamine. Additionally, ISO significantly decreased scopolamine-induced acetylcholinesterase and thiobarbituric acid reactive substance activities in both the hippocampus and frontal cortex of mice. In addition, ISO significantly increased the levels of total superoxide dismutase induced by scopolamine in the hippocampus and frontal cortex. Moreover, Western blot results indicated that ISO reversed the decreases in expression of phosphorylated cAMP response element binding (CREB) and brain-derived neurotrophic factor (BDNF) in the hippocampus and frontal cortex of scopolamine-treated mice. Thus, our results provide initial evidence that ISO ameliorates scopolamine-induced memory and cognitive impairments partly by restoring the cholinergic system, antioxidant defense, and p-CREB/BDNF signaling pathway, thereby exhibiting memory-enhancing activities.

Acetylcholinesterase inhibitor from Anthocleista vogelii leaf extracts

BACKGROUND

Anthocleista vogelii (Planch) is used in folk medicine in conditions related to inflammation and oxidative stress. This suggests that some of its constituents could possess ability to reduce oxidative damage to cells and ameliorate inflammatory conditions which are two prominent features in the brain of a person suffering from Alzheimer's disease.

AIM OF STUDY

The leaf extracts were investigated for their bioactive constituents in our quest for novel compounds for the management of Alzheimer's disease.

MATERIALS AND METHODS

Anthocleista vogelii crude leaf extract obtained from 80% methanol was successively partitioned with n-hexane, dichloromethane (DCM), ethyl acetate (EtOAc) and n-butanol. This gave four solvent fractions of the crude extract. These fractions and isolated compound were subjected to acetylcholinesterase (AChE) inhibitory activity test using the microplate assay method. The structure of the isolated compound was determined using spectroscopic methods (1D and 2D NMR, and MS).

RESULTS

The results of the acetylcholinesterase inhibitory assay revealed that n-BuOH and ethyl acetate fractions had the best activity with IC₅₀ of 564.58 and 727.63 µg/mL respectively. Activity directed fractionation of each of these fractions led to the isolation of the same compound identified as a C-glucosylflavone; isovitexin-7-O-methyl ether (swertisin). This rare C-glucosylflavone co-exist as two rotamers and exhibited duplication of NMR signals. It is reported from this plant for the first time. Swertisin displayed better acetylcholinesterase inhibitory activity with IC₅₀ of 32.09 µg/mL than physostigmine (eserine) with IC₅₀ of 56.09 µg/mL used as a standard.

CONCLUSIONS

This study reports isolation and characterization of a rare C-glycosylflavone; isovitexin-7-O-methyl ether (swertisin). Isolated compound exhibited duplication of NMR signals and better acetylcholinesterase inhibitory activity than eserine used as a standard. The activity exhibited by this compound suggests that it could be useful in the management of Alzheimer's disease.

Analogous β-Carboline Alkaloids Harmaline and Harmine Ameliorate Scopolamine-Induced Cognition Dysfunction by Attenuating Acetylcholinesterase Activity, Oxidative Stress, and Inflammation in Mice

The analogous β-carboline alkaloids, harmaline (HAL) and harmine (HAR), possess a variety of biological properties, including acetylcholinesterase (AChE) inhibitory activity, antioxidant, anti-inflammatory, and many others, and have great potential for treating Alzheimer’s disease (AD). However, studies have showed that the two compounds have similar structures and in vitro AChE inhibitory activities but with significant difference in bioavailability. The objective of this study was to comparatively investigate the effects of HAL and HAR in memory deficits of scopolamine-induced mice. In the present study, mice were pretreated with HAL (2, 5, and 10 mg/kg), HAR (10, 20, and 30 mg/kg) and donepezil (5 mg/kg) by intragastrically for 7 days, and were daily intraperitoneal injected with scopolamine (1 mg/kg) to induce memory deficits and then subjected to behavioral evaluation by Morris water maze. To further elucidate the underlying mechanisms of HAL and HAR in improving learning and memory, the levels of various biochemical factors and protein expressions related to cholinergic function, oxidative stress, and inflammation were examined. The results showed that HAL and HAR could effectively ameliorate memory deficits in scopolamine-induced mice. Both of them exhibited an enhancement in cholinergic function by inhibiting AChE and inducing choline acetyltransferase (ChAT) activities, and antioxidant defense via increasing the antioxidant enzymes activities of superoxide dismutase and glutathione peroxidase, and reducing maleic diadehyde production, and anti-inflammatory effects through suppressing myeloperoxidase, tumor necrosis factor α, and nitric oxide as well as modulation of critical neurotransmitters such as acetylcholine (ACh), choline (Ch), L-tryptophan (L-Trp), 5-hydroxytryptamine (5-HT), γ-aminobutyric acid (γ-GABA), and L-glutamic acid (L-Glu). Furthermore, the regulations of HAL on cholinergic function, inflammation, and neurotransmitters were more striking than those of HAR, and HAL manifested a comparable antioxidant capacity to HAR. Remarkably, the effective dosage of HAL (2 mg/kg) was far lower than that of HAR (20 mg/kg), which probably due to the evidently differences in the bioavailability and metabolic stability of the two analogs. Taken together, all these results revealed that HAL may be a promising candidate compound with better anti-amnesic effects and pharmacokinetic characteristics for the treatments of AD and related diseases.

The memory ameliorating effects of DHP1402, an herbal mixture, on cholinergic blockade-induced cognitive dysfunction in mice

ETHNOPHARMACOLOGICAL RELEVANCE

The seeds of Ziziphus jujuba var. spinosa (Bunge) Hu ex H.F Chow (Rhamnaceae) and the roots of Codonopsis lanceolata (Siedbold & Zucc.) Benth. & Hook. f ex Trautv. (Campanulaceae), contained in the DHP1402, have long been used for treating dementia or hypomnesia as folk medicine.

AIM OF THE STUDY

It has been reported that Z. jujuba var. spinosa and C. lanceolata are effective in improving cognitive function, but via different mechanisms. Therefore, in the present study, we evaluated the synergistic effects of Z. jujuba var. spinosa and C. lanceolata on scopolamine-induced memory impairment.

MATERIALS AND METHODS

Scopolamine, a cholinergic muscarinic receptor antagonist, was used to induce cognitive dysfunction. We employed several behavioral tasks to estimate the synergistic effect of the seeds of Z. jujuba var. spinosa and the roots of C. lanceolata. In addition, we introduced the Western blotting, the antagonism passive avoidance task to investigate a synergistic effect of an herbal formulation.

RESULTS

Synergistic effects of a combination of Z. jujuba var. spinosa and C. lanceolata at a 5:1 ratio [(w/w), DHP1402] were observed against cognitive dysfunction in the passive avoidance and Y-maze tasks. DHP1402 also ameliorated memory deficits in a dose-dependent manner in these behavioral tasks, as well as in the Morris water maze task. According to the Western blot results, the phosphorylation levels of protein kinase A (PKA), extracellular signal-regulated kinase (ERK) and cAMP response element-binding protein (CREB) in the hippocampus were also increased in a synergistic manner after the administration of DHP1402. In addition, we found that the effects of DHP1402 on cognitive function were mediated by N-methyl-D-aspartate (NMDA) receptor signalling, based on the antagonism studies. Furthermore, we found that DHP1402 has inhibitory activity against acetylcholinesterase (AChE).

CONCLUSION

DHP1402 attenuates cholinergic blockade-induced cognitive dysfunction through NMDA receptor modulation, PKA-ERK-CREB pathway activation, and AChE inhibition. Therefore, DHP1402 could be a candidate for alleviating cognitive dysfunction.

Phytochemistry and Pharmacological Activities of the Genus Swertia (Gentianaceae): A Review

Swertia plants have been considered to be medicinal plants useful for the treatment of various ailments for thousands of years, especially in Asian countries. This is due to the broad variety of chemical compounds that provide multiple ligands for bonding to different endogenous biomacromolecules for patients. Chemical constituents and pharmacological activities of Swertia plants are summarized in this paper. Approximately 419 metabolites and 40 bioactive compounds have been reported from 30 Swertia species, including xanthones, flavonoids, seco-iridiods, iridiods, triterpenoids, alkaloids, volatiles, and other secondary metabolites. The bioactivities of Swertia plants include anticarcinogenic, hepatoprotective, anti-oxidant, hypoglycemic, anthelmintic, antibacterial, antifungal, anti-diabetic, gut, and airways modulatory, metabolizing isozymes inhibitory, neuroprotective, HIV-I reverse transcriptases inhibitory, anticholinergic, and CNS-depressant activities, etc. In addition, biosynthetic pathways of xanthones, and seco-iridiods, two most important secondary metabolites for Swertia, are elucidated. The xanthones biosynthetic pathway is a mixed biosynthetic pathway involved the shikimate and the malonate routes, and the seco-iridoid pathway starts with geraniol derived from IPP which is produced either via the MEP or the MVA pathway. This review will offer a reference for future researches on the protection of natural resources, the investigation of therapeutic basis, new drug development, and so forth. Metabolic pathways of some crucial active compounds were also discussed in this review.

HBK-14 and HBK-15 with antidepressant-like and/or memory-enhancing properties increase serotonin levels in the hippocampus after chronic treatment in mice

5-HT_1A and 5-HT₇ receptor ligands might have antidepressant-like properties and improve cognitive function. We previously reported significant antidepressant- and anxiolytic-like effects of two dual 5-HT_1A and 5-HT₇ receptor antagonists in various behavioral tests in rodents. As a continuation of our previous experiments, in this study we aimed to investigate whether chronic administration of 1-[(2,6-dimethylphenoxy)ethoxyethyl]-4-(2-methoxyphenyl)piperazine hydrochloride (HBK-14) and 1-[(2-chloro-6-methylphenoxy)ethoxyethyl]-4-(2-methoxyphenyl)piperazine hydrochloride (HBK-15) caused antidepressant-like effects and elevated serotonin levels in the murine hippocampus. We also evaluated cholinolytic properties and the influence of acute administration of both compounds on cognitive function in mice. To assess antidepressant-like properties and the influence on learning and memory we used forced swim test and step-through passive avoidance task in mice, respectively. Both compounds showed antidepressant-like properties and significantly elevated serotonin levels in the hippocampus after chronic treatment (HBK-14 - 2.5 mg/kg; HBK-15 - 0.625 and 1.25 mg/kg). HBK-15 administered chronically antidepressant-like activity at lower dose (0.625 mg/kg) than the dose active after acute treatment (1.25 mg/kg). None of the compounds affected locomotor activity of mice. HBK-15 possessed very weak cholinolytic properties, whereas HBK-14 did not show any effect on muscarinic receptors. Only HBK-15 (0.625 mg/kg) presented memory-enhancing properties and ameliorated cognitive impairments caused by scopolamine (1 mg/kg). Our results indicate that 5-HT_1A and 5-HT₇ antagonists might have potential in the treatment of depression and possess positive influence on cognitive function.

Ethanol extract of the seed of Zizyphus jujuba var. spinosa potentiates hippocampal synaptic transmission through mitogen-activated protein kinase, adenylyl cyclase, and protein kinase A pathways

ETHNOPHARMACOLOGICAL RELEVANCE

As the seed of Zizyphus jujuba var. spinosa (Bunge) Hu ex H.F. Chow (Rhamnaceae) has been used to sleep disturbances in traditional Chinese and Korean medicine, many previous studies have focused on its sedative effect.

AIM OF THE STUDY

Recently, we reported the neuroprotective effect of the effect of Z. jujuba var. spinosa. However, its effects on synaptic function have not yet been studied. In this project, we examined the action of ethanol extract of the seed of Z. jujuba var. spinosa (DHP1401) on synaptic transmission in the hippocampus.

MATERIALS AND METHODS

To investigate the effects of DHP1401, field recordings were conducted using hippocampal slices (400µm). Object recognition test was introduced to examine whether DHP1401 affect normal recognition memory.

RESULTS

DHP1401 (50μg/ml) induced a significant increase in synaptic activity in Shaffer collateral pathway in a concentration-dependent manner. This increase of synaptic responses was blocked by NBQX, a broad spectrum α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor antagonist, but not IEM-1460, a Ca²⁺-permeable AMPAR blocker. Moreover, U0126, a mitogen-activated protein kinase inhibitor, SQ22536, an adenylyl cyclase inhibitor, and PKI, a protein kinase A inhibitor, blocked DHP1401-induced increase in synaptic transmission. Finally, DHP1401 facilitated object recognition memory.

CONCLUSIONS

These results suggest that DHP1401 increase synaptic transmission through increase of synaptic AMPAR transmission via MAPK, AC and PAK.

Echinodorus grandiflorus: Ethnobotanical, phytochemical and pharmacological overview of a medicinal plant used in Brazil

Echinodorus grandiflorus (Cham. & Schltdl.) Micheli is a native Brazilian species used in traditional practices for the treatment of several conditions such as inflammatory diseases, arthritis and hypertension. Through a systematic review of the accumulated knowledge about the species E. grandiflorus, the botanical, phytochemistry, ethnobotanical and pharmacological properties of this medicinal plant demonstrates its potential to naturally provide anti-inflammatory and anti-oxidant with a special emphasis on anti-hypertensive and cardioprotective effects. The body of literature reports that the chemical composition of crude E. grandiflorus extracts are notably composed of diterpenoids and flavonoids metabolites. Pharmacological studies have shown that oral treatments using the hydroalcoholic extracts of leaves from this plant has a significant anti-inflammatory, anti-hypertensive, diuretic and cardioprotective effects in rats with no toxicity. The holistic activities of complex extracts are corroborated by the individuals mechanisms of action, as well as, synergistic benefits attributed to the isolated chemical major constituents in this species. In light of the serious health concerns ascribed, it is important to investigate medicinal plant species with histories of traditional use for circulatory problems to meet the growing demands by scientifically validating their use and safety.

Swertisin ameliorates pre-pulse inhibition deficits and cognitive impairment induced by MK-801 in mice

Swertisin, a plant-derived C-glucosylflavone, is known to have antidiabetic, anti-inflammatory and antioxidant effects. In the present study, we investigated in mice the effects of swertisin on glutamatergic dysfunction induced by dizocilpine (MK-801), a non-competitive N-methyl-D-aspartate receptor antagonist. In the Acoustic Startle Response test, their MK-801-induced (given 0.2 mg/kg i.p.) pre-pulse inhibition deficit was significantly attenuated by the administration of swertisin (30 mg/kg p.o.). In the Novel Object Recognition Test, the recognition memory impairments that were induced by MK-801 (0.2 mg/kg, given i.p.) were also reversed by administration of swertisin (30 mg/kg p.o.). In addition, swertisin normalized the MK-801-induced elevation of phosphorylation levels of Akt and GSK-3β signaling molecules in the prefrontal cortex. These results indicated that swertisin may be useful in managing the symptoms of schizophrenia, including sensorimotor gating disruption and cognitive impairment, and that these behavioral outcomes may be related to Akt-GSK-3β signaling in the prefrontal cortex.