Antidepressant-like effect of scopoletin, a coumarin isolated from Polygala sabulosa (Polygalaceae) in mice: Evidence for the involvement of monoaminergic systems

Scopoletin Supplementation Ameliorates Steatosis and Inflammation in Diabetic Mice

Scopoletin is a bioactive component in many edible plants and fruits. This study investigated the effects of scopoletin on hepatic steatosis and inflammation in a high-fat diet fed type 1 diabetic mice by comparison with metformin. Scopoletin (0.01%, w/w) or metformin (0.5%, w/w) was provided with a high-fat diet to streptozotocin-induced diabetic mice for 11 weeks. Both scopoletin and metformin lowered blood glucose and HbA1c , serum ALT, TNF-α and IL-6 levels, glucose intolerance, and hepatic lipid accumulation compared with the diabetic control group. Scopoletin or metformin down-regulated hepatic gene expression of triglyceride (Pparg, Plpp2, and Dgat2) and cholesterol (Hmgcr) synthesis as well as inflammation (Tlr4, Myd88, Nfkb1, Tnfa, and Il6), while it up-regulated Cyp7a1 gene. Hepatic PPARγ and DGAT2 protein levels were also down-regulated in scopoletin or metformin group compared with the control group. Scopoletin or metformin also inhibited hepatic fatty acid synthase and phosphatidate phosphohydrolase activities. These results suggest that scopoletin protects against diabetes-induced steatosis and inflammation by inhibiting lipid biosynthesis and TLR4-MyD88 pathways. Copyright © 2017 John Wiley & Sons, Ltd.

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.

In Silico Prediction of the Anti-Depression Mechanism of a Herbal Formula (Tiansi Liquid) Containing Morinda officinalis and Cuscuta chinensis

Purpose: Depression is a sickening psychiatric condition that is prevalent worldwide. To manage depression, the underlying modes of antidepressant effect of herbals are important to be explored for the development of natural drugs. Tiansi Liquid is a traditional Chinese medicine (TCM) that is prescribed for the management of depression, however its underlying mechanism of action is still uncertain. The purpose of this study was to systematically investigate the pharmacological mode of action of a herbal formula used in TCM for the treatment of depression. Methods: Based on literature search, an ingredients-targets database was developed for Tiansi Liquid, followed by the identification of targets related to depression. The interaction between these targets was evaluated on the basis of protein-protein interaction network constructed by STITCH and gene ontology (GO) enrichment analysis using ClueGO plugin. Results: As a result of literature search, 57 components in Tiansi Liquid formula and 106 potential targets of these ingredients were retrieved. A careful screening of these targets led to the identification of 42 potential targets associated with depression. Ultimately, 327 GO terms were found by analysis of gene functional annotation clusters and abundance value of these targets. Most of these terms were found to be closely related to depression. A significant number of protein targets such as IL10, MAPK1, PTGS2, AKT1, APOE, PPARA, MAPK1, MIF, NOS3 and TNF-α were found to be involved in the functioning of Tiansi Liquid against depression. Conclusions: The findings elaborate that Tiansi Liquid can be utilized to manage depression, however, multiple molecular mechanisms of action could be proposed for this effect. The observed core mechanisms could be the sensory perception of pain, regulation of lipid transport and lipopolysaccharide-mediated signaling pathway.

Monoaminergic neurotransmission is mediating the antidepressant-like effects of Passiflora edulis Sims fo. edulis

The genus Passiflora is popularly used to treat anxiety. Recent studies showed antidepressant-like effects of two varieties of P. edulis (edulis and flavicarpa) in mice. However, the mechanisms of antidepressant actions are still unknown. Here, the effects of P. edulis fo. edulis aqueous extract (AE, 100-300mg/kg, po), and ethyl acetate (AcOEt, 25-50mg/kg, po), butanol (BuOH, 25-50mg/kg, po) and residual aqueous (25-100mg/kg, po) fractions were investigated in the mouse forced swimming test. In addition, the involvement of monoamines in the P. edulis fractions-induced antidepressant actions was approached. HPLC analyses showed that AcOEt and BuOH, but not residual, fractions shared with AE the main peaks between 25 and 70min (UV 340nm), which are suggestive of flavonoids. Nortriptyline and fluoxetine reduced the immobility time and similar results were observed for AE, AcOEt and BuOH but not residual fractions. PCPA (inhibitor of 5-HT synthesis), AMPT (inhibitor of catecholamine synthesis) and sulpiride (selective D2 receptor antagonist), but not DSP-4 (noradrenergic neurotoxin), blocked the antidepressant actions of AcOEt and BuOH. In conclusion, AcOEt and BuOH fractions shared with AE similar phytochemical composition and antidepressant actions. Preserved 5-HT and dopamine transmissions were required for the antidepressant effects of P. edulis fractions.

Antipsychotic-like activity of scopoletin and rutin against the positive symptoms of schizophrenia in mouse models

In an earlier report, we demonstrated an antipsychotic-like activity of a methanolic extract of Morinda citrifolia Linn fruit in mouse models and postulated the contribution of its bioactive principles, scopoletin and rutin. Moreover, the antidopaminergic activities of scopoletin and rutin were reported in isolated vas deferens preparations. In the present study, scopoletin and rutin were assessed for antipsychotic-like activity using apomorphine-induced climbing behavior and methamphetamine-induced stereotypy in mice. The results of this study revealed that scopoletin and rutin (0.05, 0.1, 0.5, and 1 mg/kg, p.o.) had a “U-shaped” dose-dependent effect on climbing and stereotyped behaviors induced by apomorphine and methamphetamine, respectively, in mice. A significant reduction in climbing and stereotyped behaviors caused by scopoletin and rutin was observed only at a dose 0.1 mg/kg. This study suggests that scopoletin and rutin can alleviate positive symptoms of schizophrenia only at a specific dose. Further studies evaluating the effects of scopoletin and rutin on animal models for negative symptoms of schizophrenia are required for a novel drug discovery in the treatment of neuropsychiatric diseases.

Neurotoxic effects of silver nanoparticles and the protective role of rutin

The toxicological studies on silver nanoparticles (Ag-NPs) have become a hot topic over the past few decades due to their unique properties on the nanoscale and widespread in many commercial products that launched into the market recently. This study was undertaken to shed light on Ag-NPs toxicity on neurotransmitters with special emphasis on the impact of concurrent administration of rutin with Ag-NPs in the experimental rats. The oral administration of Ag-NPs in rats induced brain oxidative stress, significant alterations in neurotransmitters and amino acids. Furthermore, transcriptional levels of glutamatergic N-methyl-d-aspartate (NMDA) receptors, monoamino oxidases (MAO-A, MAO-B) and metallothionein-III (MT-III) showed a significant elevation in Ag-NPs intoxicated rats. Moreover, histological examinations revealed astrogliosis and demyelination of neurons concomitant with neuronal degeneration and vacuolation. Strikingly, oral administration of rutin counterbalanced the toxic effects triggered by Ag-NPs. Taken together, our findings suggested that oral administration of Ag-NPs induced neurotoxicity in rats and rutin mitigates these effects.

Attenuation of acute restraint stress-induced depressive like behavior and hippocampal alterations with protocatechuic acid treatment in mice

Protocatechuic acid ethyl ester (PCA), a phenolic compound, exhibits neuroprotective effects through improving endogenous antioxidant enzymatic and nonezymatic system. Based on the role of oxidative stress in modulating depressive disorders and the relationship between neuroprotective and antioxidant potential of PCA, we studied if its antidepressant like effect is associated by modulation of cerebral cortex and hippocampal antioxidant alterations. Acute restraint stress (ARS) is known to induce depressive like behavior by neuronal oxidative damage in mice. Swiss albino mice subjected to ARS exhibited an increased immobility time in forced swim test, elevated serum corticosterone and produced oxidative stress dependent alterations in cerebral cortex and hippocampus mainly increased thiobarbituric acid reactive substances and reduced catalase (CAT), superoxide dismutase (SOD) activity. Treatment with PCA was able to prevent stress induced immobility time in forced swim test without altering locomotor activity in mice. Further, PCA treatment attenuated the elevation of serum corticosterone, lipid peroxidation and restored enzymatic antioxidants in cerebral cortex and hippocampus in ARS mice. Altogether, the experimental findings demonstrate the notion that PCA exhibit antidepressant like activity might be related, at least in part, to its capability of modulating antioxidant defense system and oxidative damage induced by ARS in cerebral cortex and hippocampus in mice and thus maintain the pro-/anti-oxidative homeostasis.

Poligalen, a new coumarin from Polygala boliviensis, reduces the release of TNF and IL-6 independent of NF-kB downregulation

An unusually substituted coumarin, named poligalen, was isolated from a chloroform extract of the aerial parts of Polygala boliviensis. This coumarin was identified by one- and two-dimensional NMR techniques, and the structure of the compound was confirmed by X-ray diffraction. Poligalen exhibits immunomodulatory effects, reducing the levels of IL-6 and TNF after LPS stimulation in peritoneal macrophages. However, poligalen potentiates NF-kB activation.

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.

Paeonol attenuates lipopolysaccharide-induced depressive-like behavior in mice

The present study was designed to detect the anti-depressant effects of paeonol and the possible mechanisms in the lipopolysaccharide-induced depressive-like behavior. Open-field test(OFT), tail suspension test(TST) and forced swimming test(FST) were used to evaluate the behavioral activity. The contents of 5-hydroxytryptamine (5-HT) and norepinephrine (NE) in mice hippocampus were determined by HPLC-ECD. Serum interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α levels were evaluated by enzyme-linked immunosorbent assay (ELISA). Our results showed that LPS significantly decreased the levels of 5-HT and NE in the hippocampus. LPS also reduced open-field activity, as well as increased immobility duration in FST and TST. Paeonol administration could effectively reverse the alterations in the concentrations of 5-HT, NE and reduce the IL-6 and TNF-α levels. Moreover, paeonol effectively downregulated brain-derived neurotrophic factor (BDNF), tropomyosin-related kinase B (TrkB) and Nuclear factor-κB (NF-κB) in hippocampal. In conclusion, paeonol administration exhibited significant antidepressant-like effects in mice with LPS-induced depression.

Biphasic Effects of α-Asarone on Immobility in the Tail Suspension Test: Evidence for the Involvement of the Noradrenergic and Serotonergic Systems in Its Antidepressant-Like Activity

Alpha (α)-asarone is one of the main psychoactive compounds, present in Acorus species. Evidence suggests that the α-asarone possess an antidepressant-like activity in mice. However, the exact dose-dependent effect of α-asarone and mechanism(s) involved in the antidepressant-like activity are not clear. The present study aimed to investigate the dose-dependent effect of α-asarone and the underlining mechanism(s) involved in the antidepressant-like activity of α-asarone in the mouse model of tail suspension test (TST). In this study, the acute effect of α-asarone per se at different doses (10–100 mg/kg, i.p.) on immobility in the TST was studied. Additionally, the possible mechanism(s) involved in the antidepressant-like effect of α-asarone was studied using its interaction with noradrenergic and serotonergic neuromodulators in the TST. The present results reveal that the acute treatment of α-asarone elicited biphasic responses on immobility such that the duration of the immobility time is significantly reduced at lower doses (15 and 20 mg/kg, i.p.) but increased at higher doses (50 and 100 mg/kg, i.p.) in the TST. Besides, α-asarone at higher doses (50 and 100 mg/kg, i.p.) significantly decreased the spontaneous locomotor activity. Moreover, pretreatment of mice with noradrenergic neuromodulators such as AMPT (100 mg/kg, i.p., a catecholamine synthesis inhibitor), prazosin (1 mg/kg, i.p., an α₁-adrenoceptor antagonist), yohimbine (1 mg/kg, i.p., an α₂-adrenoceptor antagonist) and with serotonergic neuromodulators such as PCPA (100 mg/kg, i.p., once daily for four consecutive days, a serotonin synthesis inhibitor,) and WAY100635 (0.1 mg/kg, s.c., a selective 5-HT_1A receptor antagonist) significantly reversed the anti-immobility effect of α-asarone (20 mg/kg, i.p.). Taken together, our results suggest that the acute treatment with α-asarone elicited biphasic actions in the TST in which antidepressant-like effect was seen at relatively lower doses (15 and 20 mg/kg, i.p.) and depressive-like activity at relatively higher doses (50 and 100 mg/kg, i.p.). Furthermore, it has been revealed that the antidepressant-like effect of α-asarone could be mediated through both noradrenergic (α₁ and α₂ adrenoceptors) and serotonergic (particularly, 5-HT_1A receptors) systems.

Age-dependent effects of esculetin on mood-related behavior and cognition from stressed mice are associated with restoring brain antioxidant status

Dietary antioxidants might exert an important role in the aging process by relieving oxidative damage, a likely cause of age-associated brain dysfunctions. This study aims to investigate the influence of esculetin (6,7-dihydroxycoumarin), a naturally occurring antioxidant in the diet, on mood-related behaviors and cognitive function and its relation with age and brain oxidative damage. Behavioral tests were employed in 11-, 17- and 22-month-old male C57BL/6J mice upon an oral 35day-esculetin treatment (25mg/kg). Activity of antioxidant enzymes, GSH and GSSG levels, GSH/GSSG ratio, and mitochondrial function were analyzed in brain cortex at the end of treatment in order to assess the oxidative status related to mouse behavior. Esculetin treatment attenuated the increased immobility time and enhanced the diminished climbing time in the forced swim task elicited by acute restraint stress (ARS) in the 11- and 17-month-old mice versus their counterpart controls. Furthermore, ARS caused an impairment of contextual memory in the step-through passive avoidance both in mature adult and aged mice which was partially reversed by esculetin only in the 11-month-old mice. Esculetin was effective to prevent the ARS-induced oxidative stress mostly in mature adult mice by restoring antioxidant enzyme activities, augmenting the GSH/GSSG ratio and increasing cytochrome c oxidase (COX) activity in cortex. Modulation of the mood-related behavior and cognitive function upon esculetin treatment in a mouse model of ARS depends on age and is partly due to the enhancement of redox status and levels of COX activity in cortex.

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.

Scopoletin protects against methylglyoxal-induced hyperglycemia and insulin resistance mediated by suppression of advanced glycation endproducts (AGEs) generation and anti-glycation

Recently, several types of foods and drinks, including coffee, cream, and cake, have been found to result in high methylglyoxal (MG) levels in the plasma, thus causing both nutritional and health concerns. MG can be metabolized by phase-II enzymes in liver through the positive regulation of nuclear factor-erythroid 2-related factor 2 (Nrf2). In this study, we investigated the ability of scopoletin (SP) to protect against MG-induced hyperglycemia and insulin resistance. Recently, SP was shown to be a peroxisome proliferator-activated receptor-γ activator to elevate insulin sensitivity. We investigated the effects of oral administration of SP on the metabolic, biochemical, and molecular abnormalities characteristic of type 2 diabetes in MG-treated Wistar rats to understand the potential mechanism of scopoletin for diabetes protection. Our results suggested that SP activated Nrf2 by Ser40 phosphorylation, resulting in the metabolism of MG into d-lactic acid and the inhibition of AGEs generation, which reduced the accumulation of AGEs in the livers of MG-induced rats. In this manner, SP improved the results of the oral glucose tolerance test and dyslipidemia. Moreover, SP also increased the plasma translocation of glucose transporter-2 and promoted Akt phosphorylation caused by insulin treatment in MG-treated FL83B hepatocytes. In contrast, SP effectively suppressed protein tyrosine phosphatase 1B (PTP1B) expression, thereby alleviating insulin resistance. These findings suggest that SP acts as an anti-glycation and anti-diabetic agent, and thus has therapeutic potential for the prevention of diabetes.

Antidepressant-like effects of cordycepin in a mice model of chronic unpredictable mild stress

Cordycepin (3'-deoxyadenosine), a major bioactive component isolated from Cordyceps militaris, has multiple pharmacological activities. This study is attempted to investigate whether cordycepin (COR) possesses beneficial effects on chronic unpredictable mild stress- (CUMS-) induced behavioral deficits (depression-like behaviors) and explore the possible mechanisms. ICR mice were subjected to chronic unpredictable mild stress for 42 consecutive days. Then, COR and fluoxetine (FLU, positive control drug) were administered for 21 consecutive days at the last three weeks of CUMS procedure. The classical behavioral tests, open field test (OFT), sucrose preference test (SPT), tail suspension test (TST), and forced swimming test (FST), were applied to evaluate the antidepressant effects of COR. Then the serotonin (5-HT) and noradrenaline (NE) concentrations in hippocampal were evaluated by HPLC; tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in hippocampal were evaluated, and the proteins of TNF-α, IL-6, NF-κBP65 5-HT2A receptor (5-HT2AR), and brain-derived neurotrophic factor (BDNF) in hippocampal were evaluated by Western blot. Our results indicated that 6 weeks of CUMS exposure induced significant depression-like behavior, with low 5-HT and NE levels, high TNF-α and IL-6 in brain and high hippocampal TNF-α, IL-6, P-NF-κBP65, and 5-HT2AR levels, and low BDNF expression levels. Whereas, chronic COR (20, 40 mg/kg) treatments reversed the behavioral deficiency induced by CUMS exposure, treatment with COR normalized the change of TNF-α, IL-6, 5-HT, and NE levels, which demonstrated that COR could partially restore CUMS-induced 5-HT receptor impairments and inflammation. Besides, hippocampal BDNF expressions were also upregulated after COR treatments. In conclusion, COR remarkably improved depression-like behavior in CUMS mice and its antidepressant activity is mediated, at least in part, by the upregulating BDNF and downregulating 5-HT2AR levels and inflammation in hippocampus.

Anti-depressant-like effect of kaempferitrin isolated from Justicia spicigera Schltdl (Acanthaceae) in two behavior models in mice: evidence for the involvement of the serotonergic system

We evaluated the antidepressant-like effect of kaempferitrin (Km) isolated from the plant Justicia spicigera (Asteraceae), which is used in traditional medicine for relieving emotional disorders, such as "la tristeza" (sadness or dysthymia) and "el humor" (mood changes). The actions of Km were evaluated in a forced swimming test (FST) and a suspension tail test (TST) in mice. We explored the involvement of the serotonergic system and the hypothalamic-hypophysis-adrenal axis (HPA) in the antidepressant-like effect of Km. To evaluate nonspecific effects of Km on general activity, the open field test (OFT) was performed. Km at 5, 10, and 20 mg/kg induced an antidepressant-like effect. Sub-effective dose of Km (1 mg/kg) produced a synergistic effect with imipramine (6.25 mg/kg) and fluoxetine (10 mg/kg) but not with desipramine (3.12 mg/kg). Pretreatment with p-chlorophenylalanine methyl ester (PCPA), a serotonin synthesis inhibitor, N-{2-(4-(2-methoxyphenyl)-1-piperazinyl}-N-(2-pyridinyl)cyclohexecarboxamide (WAY-100635), a selective 5-HT1A receptor antagonist, and 8OH-DPAT, a selective 5-HT1A agonist, but not pindolol (10 mg/kg) blocked the anti- immobility effect induced by Km. Taken together, these results indicate that the antidepressant-like effect of Km is related to the serotonergic system, principally 5-HT1A. This effect was not related to changes in locomotor activity.

Design and synthesis of new series of coumarin-aminopyran derivatives possessing potential anti-depressant-like activity

A new series of coumarin based aminopyran derivatives were designed, synthesized and evaluated for their preclinical antidepressant effect on Swiss albino mice. Among the series, compounds 21, 25, 26, 27, 32 and 33 exhibited significant activity profile in forced swimming test (FST). Compound 27 was most efficacious, which at a very low dose of 0.5mg/kg reduced the time of immobility by 86.5% as compared to the standard drug fluoxetine (FXT) which reduced the immobility time by 69.8% at the dose of 20mg/kg, ip. In addition, all active compounds were screened in dose dependent manner (at doses of 0.25, 0.5, 1mg/kg ip) in FST and tail suspension test (TST). Interestingly, all active compounds did not caused any significant alteration of locomotor activity in mice as compared to control, indicating that the hybrids did not produce any motor impairment effects. The results indicate that coumarin-aminopyran derivatives may have potential therapeutic value for the management of mental depression.

Guanosine prevents behavioral alterations in the forced swimming test and hippocampal oxidative damage induced by acute restraint stress

Guanosine is a guanine-based purine that modulates glutamate uptake and exerts neurotrophic and neuroprotective effects. In a previous study, our group demonstrated that this endogenous nucleoside displays antidepressant-like properties in a predictive animal model. Based on the role of oxidative stress in modulating depressive disorders as well as on the association between the neuroprotective and antioxidant properties of guanosine, here we investigated if its antidepressant-like effect is accompanied by a modulation of hippocampal oxidant/antioxidant parameters. Adult Swiss mice were submitted to an acute restraint stress protocol, which is known to cause behavioral changes that are associated with neuronal oxidative damage. Animals submitted to ARS exhibited an increased immobility time in the forced swimming test (FST) and the administration of guanosine (5mg/kg, p.o.) or fluoxetine (10mg/kg, p.o., positive control) before the exposure to stressor prevented this alteration. Moreover, the significantly increased levels of hippocampal malondialdehyde (MDA; an indicator of lipid peroxidation), induced by ARS were not observed in stressed mice treated with guanosine. Although no changes were found in the hippocampal levels of reduced glutathione (GSH), the group submitted to ARS procedure presented enhanced glutathione peroxidase (GPx), glutathione reductase (GR), superoxide dismutase (SOD) activities and reduced catalase (CAT) activity in the hippocampus. Guanosine was able to prevent the alterations in GPx, GR, CAT activities, and in SOD/CAT activity ratio, but potentiated the increase in SOD activity elicited by ARS. Altogether, the present findings indicate that the observed antidepressant-like effects of guanosine might be related, at least in part, to its capability of modulating antioxidant defenses and mitigating hippocampal oxidative damage induced by ARS.

The antidepressant-like effect of 7-fluoro-1,3-diphenylisoquinoline-1-amine in the mouse forced swimming test is mediated by serotonergic and dopaminergic systems

The aim of the present study was to investigate the role of monoaminergic system in the antidepressant-like action of 7-fluoro-1,3-diphenylisoquinoline-1-amine (FDPI), a derivative of isoquinoline class, in Swiss mice. The antidepressant-like effect of FDPI was characterized in the modified forced swimming test (FST) and the possible mechanism of action was investigated by using serotonergic, dopaminergic and noradrenergic antagonists. Monoamine oxidase (MAO) activity and [(3)H]serotonin (5-HT) uptake were determined in prefrontal cortices of mice. The results showed that FDPI (1, 10 and 20mg/kg, i.g.) reduced the immobility time and increased the swimming time but did not alter climbing time in the modified FST. These effects were similar to those of paroxetine (8mg/kg, i.p.), a positive control. Pretreatments with p-chlorophenylalanine (100mg/kg, i.p., an inhibitor of 5-HT synthesis), WAY100635 (0.1mg/kg, s.c., 5-HT1A antagonist), ondansetron (1mg/kg, i.p., a 5-HT3 receptor antagonist), haloperidol (0.2mg/kg, i.p., a non-selective D2 receptor antagonist) and SCH23390 (0.05mg/kg, s.c., a D1 receptor antagonist) were effective to block the antidepressant-like effect of FDPI at a dose of 1mg/kg in the FST. Ritanserin (1mg/kg, i.p., a 5-HT2A/2C receptor antagonist), sulpiride (50mg/kg, i.p., a D2 and D3 receptor antagonist), prazosin (1mg/kg, i.p., an α1 receptor antagonist), yohimbine (1mg/kg, i.p., an α2 receptor antagonist) and propranolol (2mg/kg, i.p., a β receptor antagonist) did not modify the effect of FDPI in the FST. FDPI did not change synaptosomal [(3)H]5-HT uptake. At doses of 10 and 20mg/kg FDPI inhibited MAO-A and MAO-B activities. These results suggest that antidepressant-like effect of FDPI is mediated mostly by serotonergic and dopaminergic systems.

A new xanthone from Moutabea guianensis Aubl

The ethyl acetate extract of the roots of Moutabea guianensis gave 1,6-dihydroxy-4,7,8-trimethoxy-9H-xanthen-9-one (1), a new xanthone. The isolation was accomplished by column chromatography on silica gel and the structural elucidation of this compound was established by spectroscopic analyses including 1D and 2D NMR and HRESIMS.

Effect of noni (Morinda citrifolia Linn.) fruit and its bioactive principles scopoletin and rutin on rat vas deferens contractility: an ex vivo study

This study examined the effect of methanolic extract of Morinda citrifolia Linn. (MMC) and its bioactive principles, scopoletin and rutin, on dopamine- and noradrenaline-evoked contractility in isolated rat vas deferens preparations. MMC (1-40 mg/mL), scopoletin (1-200 μg/mL), and rutin hydrate (0.6-312.6 μg/mL) dose-dependently inhibited the contractility evoked by submaximal concentrations of both dopamine and noradrenaline, respectively. Haloperidol and prazosin, reference dopamine D2, and α 1-adrenoceptors antagonists significantly reversed the dopamine- and noradrenaline-induced contractions, respectively, in a dose-dependent manner. Interestingly, MMC per se at higher doses (60-100 mg/mL) showed dose-dependent contractile response in rat vas deferens which was partially inhibited by high doses of haloperidol but not by prazosin. These results demonstrated the biphasic effects of MMC on dopaminergic system; that is, antidopaminergic effect at lower concentrations (<40 mg/mL) and dopaminergic agonistic effect at higher concentrations (>60 mg/mL). However, similar contractile response at high doses of scopoletin (0.5-5 mg/mL) and rutin hydrate (0.5-5 mg/mL) per se was not observed. Therefore, it can be concluded that the bioactive principles of MMC, scopoletin, and rutin might be responsible for the antidopaminergic and antiadrenergic activities of MMC.

Emodin opposes chronic unpredictable mild stress induced depressive-like behavior in mice by upregulating the levels of hippocampal glucocorticoid receptor and brain-derived neurotrophic factor

Emodin, the major active component of Rhubarb, has shown neuroprotective activity. This study is attempted to investigate whether emodin possesses beneficial effects on chronic unpredictable mild stress (CUMS)-induced behavioral deficits (depression-like behaviors) and explore the possible mechanisms. ICR mice were subjected to chronic unpredictable mild stress for 42 consecutive days. Then, emodin and fluoxetine (positive control drug) were administered for 21 consecutive days at the last three weeks of CUMS procedure. The classical behavioral tests: open field test (OFT), sucrose preference test (SPT), tail suspension test (TST) and forced swimming test (FST) were applied to evaluate the antidepressant effects of emodin. Then plasma corticosterone concentration, hippocampal glucocorticoid receptor (GR) and brain-derived neurotrophic factor (BDNF) levels were tested to probe the mechanisms. Our results indicated that 6 weeks of CUMS exposure induced significant depression-like behavior, with high, plasma corticosterone concentration and low hippocampal GR and BDNF expression levels. Whereas, chronic emodin (20, 40 and 80 mg/kg) treatments reversed the behavioral deficiency induced by CUMS exposure. Treatment with emodin normalized the change of plasma corticosterone level, which demonstrated that emodin could partially restore CUMS-induced HPA axis impairments. Besides, hippocampal GR (mRNA and protein) and BDNF (mRNA) expressions were also up-regulated after emodin treatments. In conclusion, emodin remarkably improved depression-like behavior in CUMS mice and its antidepressant activity is mediated, at least in part, by the up-regulating GR and BDNF levels in hippocampus.

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.

Anti-inflammatory action of hydroalcoholic extract, dichloromethane fraction and steroid α-spinasterol from Polygala sabulosa in LPS-induced peritonitis in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Polygala sabulosa A. W. Bennett is a small herb popularly known as "timutu-pinheirinho" that is widely distributed in southern Brazil and that is used to treat disorders of the bowel and kidney and as a topical anesthetic and expectorant in folk medicine. This study was designed to investigate the anti-inflammatory properties of the hydroalcoholic extract (HEPs), CH2Cl2 fraction and the steroid α-spinasterol obtained from the aerial parts of Polygala sabulosa in a model of acute inflammation induced by intraperitoneal injection of bacterial lipopolysaccharide in mice.

MATERIALS AND METHODS

The anti-inflammatory effect of HEPs (3-300 mg/kg, i.g.), CH2Cl2 fraction (0.003-30 mg/kg, i.g.) and steroid α-spinasterol (0.001-1mg/kg, i.p. or 1-10mg/kg, i.g.), were evaluated in mice subjected to the acute inflammation caused by intraperitoneal (i.p.) injection of lipopolysaccharide (LPS, 0.02 µg/kg). The anti-inflammatory activity of the HEPs, CH2Cl2 fraction and steroid were assessed by determining the total numbers of leukocytes and differential cell counts (neutrophils and mononuclear cells) and levels of pro-inflammatory (IL-1β, TNF-α, IL-6) or anti-inflammatory (IL-10) cytokines in peritoneal fluid.

RESULTS

The administration of HEPs (3-300 mg/kg, i.g.) completely inhibited inflammatory cell infiltration (300 mg/kg, i.g.) and it reduced TNF-α (100-300 mg/kg) and IL-1β (100mg/kg) levels in LPS-injected mice. Furthermore, the administration of CH2Cl2 fraction (0.003-30 mg/kg, i.g.) or α-spinasterol (0.001-10mg/kg, by i.p. or i.g.) significantly reduces inflammatory cell infiltration in LPS-injected mice. Moreover, dexamethasone (0.5mg/kg, i.p., used as a positive control) inhibited inflammatory cell infiltration and reduced the levels of TNF-α, IL-1β and IL-6 in LPS-injected mice.

CONCLUSIONS

Taken together, these results provide the first experimental evidence demonstrating that HEPs have significant anti-inflammatory effects on LPS-induced inflammation. These effects appear to be, at least in part, due to the presence of α-spinasterol. These findings support the widespread use of Polygala sabulosa in popular medicine and demonstrate that this plant has therapeutic potential for the development of phytomedicines with anti-inflammatory properties.

The activation of α1-adrenoceptors is implicated in the antidepressant-like effect of creatine in the tail suspension test

The antidepressant-like activity of creatine in the tail suspension test (TST) was demonstrated previously by our group. In this study we investigated the involvement of the noradrenergic system in the antidepressant-like effect of creatine in the mouse TST. In the first set of experiments, creatine administered by i.c.v. route (1 μg/site) decreased the immobility time in the TST, suggesting the central effect of this compound. The anti-immobility effect of peripheral administration of creatine (1 mg/kg, p.o.) was prevented by the pretreatment of mice with α-methyl-p-tyrosine (100 mg/kg, i.p., inhibitor of tyrosine hydroxylase), prazosin (1 mg/kg, i.p., α1-adrenoceptor antagonist), but not by yohimbine (1 mg/kg, i.p., α2-adrenoceptor antagonist). Creatine (0.01 mg/kg, subeffective dose) in combination with subeffective doses of amitriptyline (1 mg/kg, p.o., tricyclic antidepressant), imipramine (0.1 mg/kg, p.o., tricyclic antidepressant), reboxetine (2 mg/kg, p.o., selective noradrenaline reuptake inhibitor) or phenylephrine (0.4 μg/site, i.c.v., α1-adrenoceptor agonist) reduced the immobility time in the TST as compared with either drug alone. These results indicate that the antidepressant-like effect of creatine is likely mediated by an activation of α1-adrenoceptor and that creatine produces synergistic effects in the TST with antidepressants that modulate noradrenaline transporter, suggesting that an improvement in the response to the antidepressant therapy may occur when creatine is combined with these antidepressants. Furthermore, the synergistic effect of creatine (0.01 mg/kg, p.o.) and reboxetine (2 mg/kg, p.o.) combination was abolished by the α1-adrenoceptor antagonist prazosin, indicating that the antidepressant-like effect of combined therapy is likely mediated by an activation of α1-adrenoceptor.

[Preparative isolation and purification of scopoletin from Lycium barbarum L. by high-speed countercurrent chromatography]

An effective and rapid method for the separation of scopoletin from Lycium barbarum L. by high-speed counter-current chromatography (HSCCC) was established. The ethyl alcohol extract of the Lycium barbarum L. was initially separated using D-101 macroporous resins and further purified by HSCCC. The thin layer chromatography coupling with fluorometric spectrophotometry (TLC-F) method was used to determine the partitioning coefficient of scopoletin in different solvent systems. The results showed the solvent system of chloroformmethanol-water (10:7:3, v/v/v) was the best one for the HSCCC separation. A total of 10.2 mg of scopoletin with high purity (98. 3%, analyzed by high performance liquid chromatography (HPLC)) was obtained in one step by the following separation procedures: the upper phase as the stationary phase, the lower phase as the mobile phase, with a flow rate of 1.5 mL/min, with the apparatus rotated at 850 r/min, and detected at 365 nm. The structure of the obtained compound was identified by 'H-nuclear magnetic resonance and 13C-nuclear magnetic resonance. The sample could be injected into HSCCC twice successively and the whole separation was achieved with satisfactory peak resolution. These results suggested that the TLC-F method is useful in measuring the partitioning coefficients of the target compound in HSCCC solvent systems and HSCCC is a fast and convenient method for the separation of scopoletin.

Antidepressant-like effect of ursolic acid isolated from Rosmarinus officinalis L. in mice: evidence for the involvement of the dopaminergic system

Ursolic acid, a constituent from Rosmarinus officinalis, is a triterpenoid compound which has been extensively known for its anticancer and antioxidant properties. In the present study, we investigated the antidepressant-like effect of ursolic acid isolated from this plant in two predictive tests of antidepressant property, the tail suspension test (TST) and the forced swimming test (FST) in mice. Furthermore, the involvement of dopaminergic system in its antidepressant-like effect was investigated in the TST. Ursolic acid reduced the immobility time in the TST (0.01 and 0.1mg/kg, p.o.) and in the FST (10mg/kg, p.o.), similar to fluoxetine (10mg/kg, p.o.), imipramine (1mg/kg, p.o.) and bupropion (10mg/kg, p.o.). The effect of ursolic acid (0.1mg/kg, p.o.) in the TST was prevented by the pretreatment of mice with SCH23390 (0.05mg/kg, s.c., a dopamine D(1) receptor antagonist) and sulpiride (50mg/kg, i.p., a dopamine D(2) receptor antagonist). The administration of a sub-effective dose of ursolic acid (0.001mg/kg, p.o.) in combination with sub-effective doses of SKF38393 (0.1mg/kg, s.c., a dopamine D(1) receptor agonist), apomorphine (0.5μg/kg, i.p., a preferential dopamine D(2) receptor agonist) or bupropion (1mg/kg, i.p., a dual dopamine/noradrenaline reuptake inhibitor) reduced the immobility time in the TST as compared with either drug alone. Ursolic acid and dopaminergic agents alone or in combination did not cause significant alterations in the locomotor and exploratory activities. These results indicate that the antidepressant-like effect of ursolic acid in the TST is likely mediated by an interaction with the dopaminergic system, through the activation of dopamine D(1) and D(2) receptors.

Antidepressant-like effect of creatine in mice involves dopaminergic activation

Creatine has been shown to play a significant role in health and disease. However, studies concerning its effect on mood are scarce. This study investigated the effect of creatine (p.o.) in the tail suspension test, a predictive test of antidepressant activity. Creatine reduced the immobility time in the tail suspension test (0.1-1000 mg/kg, male and female mice), without affecting locomotor activity. Furthermore, the involvement of the dopaminergic system in creatine-induced antidepressant-like effect in male mice in the tail suspension test was investigated. The anti-immobility effect of creatine (1 mg/kg) was prevented by the pre-treatment of mice with haloperidol (0.2 mg/kg, intraperitoneal (i.p.) route, non-selective dopamine receptor antagonist), (R)-(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride (SCH23390; 0.05 mg/kg, subcutaneous (s.c.) route, dopamine D₁ receptor antagonist) and sulpiride (50 mg/kg, i.p., dopamine D₂ receptor antagonist). Creatine (0.01 mg/kg, sub-effective dose) in combination with sub-effective doses of (1-phenyl-7,8-dihydroxy-2,3,4,5-tetrahydro-1H-3-benzazepine) hydrochloride (SKF38393; 0.1 mg/kg, s.c., dopamine D₁ receptor agonist), apomorphine (0.5 µg/kg, i.p., preferential dopamine D₂ receptor agonist) or bupropion (1 mg/kg, p.o., dopamine reuptake inhibitor with subtle activity on noradrenergic reuptake) reduced the immobility time in the tail suspension test as compared with either drug alone. These results indicate that the antidepressant-like effect of creatine is likely mediated by an activation of dopamine D₁ and D₂ receptors.

Involvement of monoaminergic systems in the antidepressant-like effect of Eugenia brasiliensis Lam. (Myrtaceae) in the tail suspension test in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Several species of Eugenia L. are used in folk medicine for the treatment of various diseases. Eugenia brasiliensis is used for the treatment of inflammatory diseases, whereas Eugenia. uniflora is used for the treatment of symptoms related to depression and mood disorders, and is used in Brazil by the Guarani Indians as a tonic stimulant.

AIM OF THE STUDY

To investigate the antidepressant-like effect of hydroalcoholic extracts of different plant species of genus Eugenia and to characterize the participation of the monoaminergic systems in the mechanism of action of the specie that afforded the most prominent antidepressant-like efficacy.

MATERIALS AND METHODS

In the first set of experiments, the effects of hydroalcoholic extracts of Eugenia beaurepaireana, Eugenia brasiliensis, Eugenia catharinae, Eugenia umbelliflora and Eugenia uniflora and the antidepressant fluoxetine (positive control) administered acutely by p.o. route were evaluated in the tail suspension test (TST) and locomotor activity was assessed in the open-field test in mice. In the second set of experiments, the involvement of the monoaminergic systems in the antidepressant-like activity of Eugenia brasiliensis was evaluated by treating mice with several pharmacological agonists and antagonists. The effects of the combined administration of sub-effective doses of Eugenia brasiliensis and the antidepressants fluoxetine, imipramine and bupropion were also evaluated.

RESULTS

The administration of the extracts from Eugenia brasiliensis, Eugenia catharinae and Eugenia umbelliflora, but not Eugenia beaurepaireana and Eugenia uniflora, exerted a significant antidepressant-like effect, without altering locomotor activity. The behavioral profile was similar to fluoxetine. Pre-treatment of mice with ketanserin, haloperidol, SCH23390, sulpiride, prazosin and yohimbine prevented the reduction of immobility time induced by Eugenia brasiliensis. Treatment with sub-effective doses of WAY100635, SKF38393, apomorphine, phenylephrine, but not clonidine, combined with a sub-effective dose of Eugenia brasiliensis decreased the immobility time in the TST. Furthermore, the combined administration of sub-effectives doses of Eugenia brasiliensis with fluoxetine, imipramine and bupropion produced an antidepressant-like effect.

CONCLUSIONS

This study show, for the first time, the antidepressant-like effect of species of the genus Eugenia, especially Eugenia brasiliensis, whose effects in the TST seem to be mediated by serotoninergic (5-HT(1A) and 5-HT(2) receptors), noradrenergic (α(1)-adrenoceptor) and dopaminergic (dopamine D(1) and D(2) receptors) systems.

Antidepressant-like effects of fractions, essential oil, carnosol and betulinic acid isolated from Rosmarinus officinalis L

The aim of this study was to investigate the antidepressant-like effect of fractions from Rosmarinus officinalis L.: ethyl acetate 1 and 2 (AcOEt1 and 2), hexane (HEX), ethanolic (ET), and essential oil-free (EOF) fractions, as well as essential oil, the isolated compounds carnosol and betulinic acid in the tail suspension test, a predictive test of antidepressant activity. Swiss mice were acutely administered by oral route (p.o.) with fractions, essential oil or isolated compounds, 60 min before the tail suspension test or open-field test. All of them produced a significant antidepressant-like effect: AcOEt1, ET, EOF fractions and essential oil (0.1-100mg/kg, p.o); HEX (0.1-10mg/kg, p.o) and AcOEt2 fraction (0.1-1mg/kg, p.o), carnosol (0.01-0.1mg/kg, p.o.) isolated from the HEX fraction and betulinic acid (10mg/kg, p.o.), isolated from the AcOEt1 and AcOEt2 fractions. No psychostimulant effect was shown in the open-field test, indicating that the effects in the tail suspension test are specific. This study suggests that carnosol and betulinic acid could be responsible for the anti-immobility effect of extracts from R. officinalis.