Antidepressant Effect of Extracts from Ginkgo biloba Leaves in Behavioral Models

Deciphering Neuroprotective Effect of Rosmarinus officinalis L. (syn. Salvia rosmarinus Spenn.) through Preclinical and Clinical Studies

Rosmarinus officinalis L. (RO, rosemary) is a well-known medicinal, aromatic, and culinary herb with traditional use in European folk medicine against memory deficits and neurodegenerative disorders. This review highlights the different neuroprotective activities of RO investigated in both preclinical and clinical studies, as well as in silico molecular docking of bioactive compounds found in RO. The neuroprotective effect of RO was searched through databases including PubMed, Web of Science (WoS), Scopus, and Clinical Trials using the keywords "Rosmarinus officinalis, rosemary, neuroprotective effect, memory, cognitive dysfunction, Alzheimer's disease." RO, which is rich in secondary metabolites that have memory-enhancing potential, has displayed neuroprotection through different molecular mechanisms such as inhibition of cholinesterase, modulation of dopaminergic and oxytocinergic systems, mediation of oxidative and inflammatory proteins, involved in neuropathic pain, among others. RO extracts exhibited antidepressant and anxiolytic activities. Also, the plant has shown efficacy in scopolamine-, lipopolysaccharide-, AlCl3-, and H2O2-induced amnesia as well as amyloid-beta- and ibotenic acid-induced neurotoxicity and chronic constriction injury-related oxidative stress memory and cognitive impairments in animal models. A few clinical studies available supported the neuroprotective effects of RO and its constituents. However, more clinical studies are needed to confirm results from preclinical studies further and should include not only placebo-controlled studies but also studies including positive controls using approved drugs. Many studies underlined that constituents of RO may have the potential for developing drug candidates against Alzheimer's disease that possess high bioavailability, low toxicity, and enhanced penetration to CNS, as revealed from the experimental and molecular docking analysis.

Novel substituted 4-(Arylethynyl)-Pyrrolo[2,3-d]pyrimidines negative allosteric modulators (NAMs) of the metabotropic glutamate receptor subtype 5 (mGlu5) Treat depressive disorder in mice

In view of the fact that the G-protein-coupled receptors (GPCRs) sit at the top of the signaling pathways triggering a diverse range of signaling cascades towards a cellular event, GPCRs are regarded as central drug targets. mGlu5, a type of classical GPCRs, is highly expressed in the central nervous system (CNS) and responds to the neurotransmitter glutamate. Researches show that mGlu5 is a potential drug target for the treatment of depression. Up to now, multiple mGlu5 negative allosteric modulators (NAMs) have entered clinical trials, but no small molecule mGlu5 NAM has yet to reach market. Herein, we report the structural optimization and structure-activity relationship studies of a series of novel mGlu5 NAMs. Among them, the novel compound 10b is a high-affinity mGluR5 antagonist, with an IC50 value of 11.5 nM. Besides, we evaluated the anti-depressant effect of compound 10b using the chronic unpredictable mild stress (CUMS)-induced depression model. The data showed that the mice in CUMS group were featured by decreased level of serum 5-HT and increased level of serum CORT, and the expression of synaptic proteins were reduced, including GluA1, GluA2, p-PKA, BDNF and TrkB. However, those factors for identifying sensitivity to depression-like behaviors could be improved by compound 10b treatment. The preliminary toxicology evaluations indicated that compound 10b had a good safety profile in vivo. Collectively, the compound 10b represents a promising lead compound for the treatment of depressive disorder.

Flavonols in Action: Targeting Oxidative Stress and Neuroinflammation in Major Depressive Disorder

Major depressive disorder is one of the most common mental illnesses that highly impairs quality of life. Pharmacological interventions are mainly focused on altered monoamine neurotransmission, which is considered the primary event underlying the disease's etiology. However, many other neuropathological mechanisms that contribute to the disease's progression and clinical symptoms have been identified. These include oxidative stress, neuroinflammation, hippocampal atrophy, reduced synaptic plasticity and neurogenesis, the depletion of neurotrophic factors, and the dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis. Current therapeutic options are often unsatisfactory and associated with adverse effects. This review highlights the most relevant findings concerning the role of flavonols, a ubiquitous class of flavonoids in the human diet, as potential antidepressant agents. In general, flavonols are considered to be both an effective and safe therapeutic option in the management of depression, which is largely based on their prominent antioxidative and anti-inflammatory effects. Moreover, preclinical studies have provided evidence that they are capable of restoring the neuroendocrine control of the HPA axis, promoting neurogenesis, and alleviating depressive-like behavior. Although these findings are promising, they are still far from being implemented in clinical practice. Hence, further studies are needed to more comprehensively evaluate the potential of flavonols with respect to the improvement of clinical signs of depression.

Herbal Approaches in the Management of Mental Depression

BACKGROUND

Human's existence has become more stressful these days, most likely for the sake of improving one's lifestyle and fulfilling one's aspirations and needs. Depression is the most frequent neurological disorder, which affects millions of individuals worldwide. In clinical research, depression is the second most frequent chronic disease. A variety of herbal medications thought to have antidepressant-like effects have been reported in ancient pharmacopoeias from around the world. These provide several prospective chemicals that could be developed into modern mental medications while also causing no noticeable negative effects.

OBJECTIVE

The review is written to provide herbal treatment and comprehensive information about depression.

METHODS

Plants and plant formulations that were found effective in the treatment of depression are thoroughly reviewed. The antidepressant efficacies of medicinal plants, as well as their dosages, are investigated using experimental models. The review article contains 140 plants possessing antidepressant properties, 11 commercial formulations, and 25 active/isolated ingredients, as well as their chemical structure, which have been thoroughly reviewed with antidepressant activity after studying 283 references.

RESULTS

Literature revealed that a variety of medicinal plants are effective for the treatment of depression such as Hypericum perforatum, Catha edulis, Tinospora cordifolia, Curcuma longa, Ferula foetida, Rhodio larosea, Glycyrrhiza glabra, Crocus sativus, Ocimumba silicum and Embelica officinalis.

CONCLUSION

Potential compounds isolated from medicinal plants for the treatment of depressive disorders need to be established and herbal plant research could aid in this endeavour.

Design, Synthesis, and Evaluation of Isoindoline Derivatives as New Antidepressant Agents

Background:

Isoindoline derivatives exhibit a wide range of biological activities and have attracted considerable attention. However, few studies have been conducted on their antidepressant activity.

Objective:

Here, we designed and synthesized a series of isoindoline derivatives and studied their antidepressant activities.

Method:

Forced swimming test (FST) and tail suspension test (TST) were used to evaluate the antidepressant activity of the target compounds. The most active compound was used to evaluate the exploratory activity of the animals by the open-field test. 5-HT concentration was estimated to evaluate if the compound has an effect on the mice brain by using ELISA. The biological activities of the compounds were verified by molecular docking studies. The pharmacokinetic properties of the target compounds were predicted by Discovery Studio (DS) 2020.

Results:

The results of the pharmacological experiments showed that most isoindoline derivatives exhibited significant antidepressant activity. Among these compounds, compound 4j showed the highest antidepressant activity. The results of the measurement of 5-HT levels in the brains of mice indicate that the antidepressant activity of isoindoline derivatives may be mediated by elevated 5-HT levels. Compound 4j was used in molecular docking experiments to simulate the possible interaction of these compounds with the 5-HT1A receptor. The results demonstrated that compound 4j had a significant interaction with amino acids around the active site of the 5-HT1A receptor in the homology model.

Conclusion:

Isoindoline derivatives synthesized in this study have a significant antidepressant activity. These findings can be useful in the design and synthesis of novel antidepressants.

Design, Synthesis, and In Vivo and In Silico Evaluation of Coumarin Derivatives with Potential Antidepressant Effects

In this study, a series of coumarin derivatives were designed and synthesized, their structures were characterized using nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS) testing methods. In the pharmacological experiment, two behavior-monitoring methods, the forced swim test (FST) and the tail suspension test (TST), were used to determine the antidepressant activity of coumarin derivatives. Compounds that showed potential activity were analyzed for their effects on 5-hydroxytryptamine (5-HT) levels in the brains of mice. Molecular docking experiments to simulate the possible interaction of these compounds with the 5-HT1A receptor was also be predicted. The results of the pharmacological experiments showed that most coumarin derivatives exhibited significant antidepressant activity. Among these compounds, 7-(2-(4-(4-fluorobenzyl)piperazin-1-yl)-2-oxoethoxy)-2H-chromen-2-one (6i) showed the highest antidepressant activity. The results of the measurement of 5-HT levels in the brains of mice indicate that the antidepressant activity of coumarin derivatives may be mediated by elevated 5-HT levels. The results of molecular docking demonstrated that compound 6i had a significant interaction with amino acids around the active site of the 5-HT1A receptor in the homology model. The physicochemical and pharmacokinetic properties of the target compounds were also predicted using Discovery Studio (DS) 2020 and Chemdraw 14.0.

Medicinal Plants in the Treatment of Depression: Evidence from Preclinical Studies

Medicinal plants and their extracts are natural remedies with enormous potential for treating various diseases, including depression and anxiety. In the case of depression, hundreds of plants have traditionally been used in folk medicine for generations. Different plant extracts and natural products have been analyzed as potential antidepressant agents with validated models to test for antidepressant-like effects in animals, although other complementary studies have also been employed. Most of these studies focus on the possible mediators implicated in these potential effects, with dopamine, serotonin, and noradrenaline being the principal neurotransmitters implicated, both through interference with receptors and with their metabolism by monoamino oxidases, as well as through neuro-endocrine and neuroprotective effects. There are approximately 650 reports of antidepressant-like medicinal plants in PubMed; 155 of them have been compiled in this review, with a relevant group yielding positive results. Saffron and turmeric are the most relevant species studied in both preclinical and clinical studies; St. John's wort or kava have also been tested extensively. To the best of our knowledge, no review to date has provided a comprehensive understanding of the biomolecular mechanisms of action of these herbs or of whether their potential effects could have real benefits. The purpose of this narrative review is to provide an update regarding medicinal plants from the year 2000 to the present to examine the therapeutic potential of these antidepressant-like plants in order to contribute to the development of new therapeutic methods to alleviate the tremendous burden that depression causes worldwide.

Salvia officinalis and Lippia triphylla: Chemical characterization and evaluation of antidepressant-like activity

Salvia officinalis (Lamiaceae) and Lippia triphylla (Verbenaceae) are two plants known for their therapeutic effects in conventional medicine for the treatment of a wide extent of diseases, including the ones on the central nervous system. In the present study, the impact of aqueous extract from the leaves of these two herbs for the treatment of depression was examined. The phytochemical profile highlighted the presence of eighteen and ten polyphenolic compounds in Salvia officinalis and Lippia triphylla, respectively. The antidepressant effects of such extracts were assessed using two tests: the forced swimming test (FST) and tail suspension test (TST) in swiss albino mice. Five mice were partitioned into each group: control (distilled water), standard (Imipramine hydrochloride, 25 mg/kg) and three test ones treated with increased doses of aqueous extracts (250-500-1000 mg/kg), orally administered for two weeks. The acute treatment of the mice with aqueous extracts of Salvia officinalis and Lippia triphylla reduced significantly the time of immobility in the forced swimming test (p < 0.001) as compared to control group, and also decreased significantly the time of immobility of mice in the tail suspension test (p < 0.001). The findings attained in this work show how both plants possess potential anti-depressant-like effects; however, the translation from the results presented in this work to a potential use as therapeutic agents would require the acquisition of a stronger scientific evidence.

Anti-stress effects of polyphenols: animal models and human trials

Polyphenols, a category of plant compounds that contain multiple phenol structural units, are widely distributed throughout the plant kingdom and have multiple benefits for human health including anti-obesity, anti-hyperglycemic, and anti-hyperlipidemic effects. Additionally, polyphenols have recently gained attention for their anti-stress effects. In this review article, we summarize physiological responses against exposure to stressors and discuss biomarkers for exposure to stressors that are widely used in animal studies and human trials. We also review commonly used animal models for evaluating anti-stress effects. Finally, we discuss recent findings related to the anti-stress effects of polyphenols evaluated in animal models and human trials, and their putative mechanisms. These emerging data require further investigation in scientific studies and human trials to evaluate the anti-stress effects of polyphenols and their potential use for the prevention of stress-related health problems.

Synthesis of 1,3,4-oxadiazoles derivatives with antidepressant activity and their binding to the 5-HT1A receptor

In this study, two series of 1,3,4-oxadiazole derivatives were designed and synthesized using the forced swimming test (FST) model to test the antidepressant activity of the target compound in vivo. Five compounds with potential activity were selected from the FST model to test affinity with 5-HT_1A receptor in vitro. The results of the FST experiment showed that compound N-(3-((5-((4-chlorobenzyl)thio)-1,3,4-oxadiazol-2-yl)methoxy)phenyl)acetamide (10g) showed the best antidepressant activity (DID = 58.93, percentage decrease in immobility duration in FST), similar to the activity of positive drug fluoxetine. Compound 10g also exhibited the most potent binding affinity to 5-HT_1A receptors (K_i = 1.52 nM). The results of the in vivo 5-HT concentration estimation in mice showed that compound 10g may have an effect on the brain. The experimental results of exploratory activity in mice showed that compound 10g did not affect spontaneous activity in the open-field test model. Molecular docking was used to study the binding mode of compound 10g and the 5-HT_1A receptor. Compound 10g showed significant interactions with residues at the active site on the 5-HT_1A receptor. The physicochemical and pharmacokinetic properties of the target compounds were predicted using Discovery Studio 2019 and ChemBioDraw Ultra 14.

Compound 10g (R = –CH₂Ph (p-Cl)) showed the best antidepressant activity in vivo and in vitro.

Persistent postural-perceptual dizziness: current approaches to diagnosis and treatment

The cause of persistent postural-perceptual dizziness (PPPD) is considered to be chronic dysfunction of the regulatory system for maintaining equilibrium in general and that of the vestibular system in particular, which causes a persistent sensation of dizziness and/or unsteadiness. The pathogenetic mechanisms of PPPD are associated with impaired adaptation to an acute vertigo or unsteadiness episode due to various causes (vestibular, lipothymic, or emotional). Patients severely experience PPPD, which often leads to avoidant behavior and even disability. The timely diagnosis of this disorder and the use of right treatment, including vestibular rehabilitation, antidepressants, and cognitive behavioral therapy, are of great importance. Currently developed new treatments for PPPD are highly therapeutically effective. Among the medicines, Ginkgo biloba extract has been shown to be effective in improving vestibular compensation.

Coumarin and 3,4-dihydroquinolinone derivatives: Synthesis, antidepressant activity, and molecular docking studies

BACKGROUND

Coumarin and 3,4-dihydroquinolinone nuclei are two heterocyclic rings that are important and widely exploited for the development of bioactive molecules. Here, we designed and synthesized a series of 3,4-dihydroquinolinone and coumarin derivatives (Compounds 8, 9, 11, 14, 15, 18-20, 23, 24 and 28 are new compounds) and studied their antidepressant activities.

METHODS

Forced swimming test (FST) and tail suspension test (TST) were used to evaluate the antidepressant activity of the target compounds. The most active compound was used to evaluate the exploratory activity of the animals by the open-field test. 5-HT concentration was estimated to evaluate if the compound has an effect on the mouse brain, by using ELISA. A 5-HT1A binding assay was also performed. The biological activities of the compounds were verified by molecular docking studies. The physicochemical and pharmacokinetic properties of the target compounds were predicted by Discovery Studio and ChemBioDraw Ultra.

RESULTS

Of all the compounds tested, compound 7 showed the best antidepressant activity, which decreased the immobility time by 65.52 s in FST. However, in the open-field test, compound 7 did not affect spontaneous activity. The results of 5-HT concentration estimation in vivo showed that compound 7 may have an effect on the mouse brain. Molecular docking results indicated that compound 7 showed significant interactions with residues at the 5-HT1A receptor using homology modeling. The results show that compound 7 exhibits good affinity for the 5-HT1A receptor.

CONCLUSION

Coumarin and 3,4-dihydroquinolinone derivatives synthesized in this study have a significant antidepressant activity. These findings can be useful in the design and synthesis of novel antidepressants.

Synthesis and Evaluation of Antidepressant Activities of 5-Aryl-4,5-dihydrotetrazolo [1,5-a]thieno[2,3-e]pyridine Derivatives

In this study, we synthetized a series of 5-aryl-4,5-dihydrotetrazolo[1,5-a]thieno[2,3-e]pyridine derivatives containing tetrazole and other heterocycle substituents, i.e., triazole, methyltriazole, and triazolone. The forced swim test (FST) and tail suspension test (TST) were used to evaluate the antidepressant activity of the target compounds. The compound 5-[4-(trifluoromethyl)phenyl]-4,5-dihydrotetrazolo[1,5-a]thieno[2,3-e]pyridine (4i) showed the highest antidepressant activity, with a reduced immobility time of 55.33% when compared with the control group. Using an open-field test, compound 4i was shown to not affect spontaneous activity of mice. The determination of in vivo 5-hydroxytryptamine (5-HT) concentration showed that compound 4i may have an effect in the mouse brain. The biological activities of all synthetized compounds were verified by molecular docking studies. Compound 4i showed significant interactions with residues of the 5-HT1A receptor homology model.

Food-derived hydrophilic antioxidant ergothioneine is distributed to the brain and exerts antidepressant effect in mice

BACKGROUND

Clinically used antidepressants suffer from various side effects. Therefore, we searched for a safe antidepressant with minimal side effects among food ingredients that are distributed to the brain. Here, we focused on ERGO (ergothioneine), which is a hydrophilic antioxidant and contained at high levels in edible golden oyster mushrooms. ERGO is a typical substrate of carnitine/organic cation transporter OCTN1/SLC22A4, which is expressed in the brain and neuronal stem cells, although little is known about its permeation through the BBB (blood-brain barrier) or its neurological activity.

METHODS

To clarify the exposure of ERGO to brain and the possible antidepressant-like effect after oral ingestion, ERGO or GOME (golden oyster mushroom extract) which contains 1.2% (w/w) ERGO was mixed with feed and provided to mice for 2 weeks, and then ERGO concentration and antidepressant-like effect were evaluated by LC-MS/MS and FST (forced swimming test) or TST (tail suspension test), respectively.

RESULTS

Diet containing ERGO or GOME greatly increased the ERGO concentrations in plasma and brain, and significantly decreased the immobility time in both FST and TST. The required amount of GOME (~37 mg/day) to show the antidepressant-like effect corresponds to at most 8 g/day in humans. In mice receiving GOME-containing diet, doublecortin-positive cells showed a significant increase from the basal level, suggesting promotion of neuronal differentiation.

CONCLUSION

Thus, orally ingested ERGO is transported across the BBB into the brain, where it may promote neuronal differentiation and alleviate symptoms of depression at plausibly achieved level of daily ingestion.

Potential Antidepressant Constituents of Nigella sativa Seeds

BACKGROUND

Nigella sativa Linn. is well known seed in the Middle East, Asia, and the Far East as a natural remedy for many ailments and as a flavoring agent proclaimed medicinal usage dating back to the ancient Egyptians, Greeks, and Romans. An authentic saying of the Prophet Muhammad (Peace Be Upon Him) about black seed is also quoted in Al-Bukhari.

OBJECTIVE

This study was carried out to evaluate the antidepressant effect and isolate the potential antidepressant constituents of the polar extract of N. sativa seeds.

MATERIALS AND METHODS

The antidepressant effect was evaluated through the immobility duration in tail suspension and forced swim tests (FSTs). Albino mice were orally treated with N. sativa polar extract and its RP-18 column chromatography fractions (50 and 100 mg/kg,).

RESULTS

The polar extract and two of its sub-fractions were significantly able to decrease the immobility time of mice when subjected to both tail suspension and FSTs, the effects are comparable to standard drug (Sertraline, 5 mg/kg). However, these treatments did not affect the number of crossings and rearing in the open field test. Phytochemical investigation of the two active fractions led to the isolation of quercetin-3-O-α-L-rhamnopyranoside 1, quercetin-7-O-β-D-gluco- pyranoside 2, tauroside E 3, and sapindoside B as the potential antidepressant constituents.

SUMMARY

Phytochemical and biological evaluation the antidepressant constituents in Nigella sativa using the tail suspension and forced swim methods afforded the isolation and identification of quercetin-3-O-α-L rhamnopyranoside, quercetin-7-O-β-D gluco pyranoside, tauroside E, and sapindoside B as the potential antidepressant constituents in the polar extract of N. sativa. The isolated compounds were identified through extensive NMR analysis (1D, 2D, ESI MS). Abbreviations used: TST: Tail suspension test, FST: Forced swim test, OFT: An Open field test.

Antidepressant-like effects of methanolic extract of Bacopa monniera in mice

BACKGROUND

Bacopa monniera has been used as a cure for various ailments that include anxiety, epileptic disorders, dementia, blood purifier, cough and rheumatism, and some important local uses of the plant are in dermatitis, anemia, diabetes, promote fertility and prevent miscarriage for many years in Bangladesh. According to this background, the aim of the study was to evaluate the antidepressant-like effect of the methanolic extract of B. monniera (MEBM) in different behavioral models such as forced swimming test (FST), measurement of locomotor activity test (MLAT) and tail suspension test (TST) on mice after two weeks treatment.

METHODS

Mice were divided into five groups (n = 5/group): control group (deionized water), standard group where Imipramine hydrochloride (30 mg/kg) was used as standard drug and three test groups where three doses of the methanolic extract of B. monniera (MEBM) (50, 100, and 200 mg/kg) was used for two weeks treatment. All the drug and test samples were administered via gavage through oral route. To assess the antidepressant-like effect of MEBM forced swimming test (FST), tail suspension test (TST) and measurement of locomotor activity test (MLAT) have been done in mice.

RESULTS

The results showed that a strong and dose-dependent antidepressant effects in different mice models. The main findings of the MEBM significantly reduced the duration of immobility times in the forced swimming test (p < 0.001). Likewise, the extract significantly decreased the immobility time in the tail suspension test (p < 0.001). Moreover, we employed an additional measurement of locomotor activity test to check the motor stimulating activity of the MEBM. The extract also significantly increased the locomotion, rearing and defecation effects in comparison to the control group (p < 0.001).

CONCLUSION

The present results clearly demonstrate that the methanolic extract of B. monniera possesses antidepressant-like activity in the animal behavioral models. The current study warrants further investigation into identification of the active compounds in herbal medicines, in particular extract of B. monniera with antidepressant-like effects.

Synthesis, potential anticonvulsant and antidepressant effects of 2-(5-methyl-2,3-dioxoindolin-1-yl)acetamide derivatives

A new series of 2-(5-methyl-2,3-dioxoindolin-1-yl)acetamide derivatives were synthesized and evaluated for their anticonvulsive activity in a pentylenetetrazole (PTZ)-evoked convulsion model and antidepressant activity in the forced swimming test (FST) model. Eleven synthesized compounds were found to be protective against PTZ-induced seizure and showed the anticonvulsant activity. In addition, four of the synthesized compounds (4l, 4m, 4p and 4q) showed potent antidepressant-like activity. Among these compounds, compound 4l was found to have the most potent antidepressant-like activity, and significantly reduced the duration of immobility time at 100 mg/kg dose level when compared to the vehicle control, which is similar to the reference drug fluoxetine.

Screening of antidepressant activity and estimation of quercetin from Coccinia indica using TLC densitometry

CONTEXT

Coccinia indica Naud (Cucurbitaceae) has been traditionally used for the treatment of depression but these claims have not been validated.

OBJECTIVES

The objective of this study is to investigate antidepressant activity of various extracts and fractions of C. indica aerial parts, and to estimate content of quercetin in the plant using TLC densitometry.

MATERIALS AND METHODS

Coccinia indica aerial parts were successively extracted using solvents in increasing order of polarity, namely n-hexane, chloroform, methanol, and water. Various extracts were evaluated for antidepressant activity at doses of 200 or 400 mg/kg, p.o., upon acute administration in mice using the forced swim test (FST). The bioactive extract was partitioned successively using solvents in increasing order of polarity, namely n-hexane, ethyl acetate, and n-butanol. All fractions were also screened for antidepressant activity at doses of 25 or 50 mg/kg, p.o., upon acute administration in mice.

RESULTS

The methanol extract significantly reduced the duration of immobility in FST at dose of 400 mg/kg without affecting locomotor activity in open field test, thus, confirmed its antidepressant activity, which was statistically equivalent to the standard drug (imipramine, 15 mg/kg, i.p.). Ethyl acetate fraction (EAF) exhibited antidepressant activity at 50 mg/kg. Comparative TLC fingerprint studies confirmed the presence of quercetin in methanol extract and EAF. Quercetin was used as a chemical marker to standardize C. indica aerial parts using the validated TLC densitometric method, and the content of quercetin was found to be 0.00172% w/w.

CONCLUSIONS

The present studies scientifically validated traditional claims of C. indica for antidepressant activity.

Quercetin and related polyphenols: new insights and implications for their bioactivity and bioavailability

The physiological functions and mechanisms of action of quercetin and its related polyphenols are highlighted, including their effects on brain, blood vessels, muscle, and intestinal microflora.

The effects of Ginkgo biloba extract on cognitive functions in aged female rats: the role of oxidative stress and brain-derived neurotrophic factor

The aim of this study was to investigate the effects of Ginkgo biloba extract (GBE) on cognitive functions as well as oxidative stress and brain-derived neurotrophic factor (BDNF) levels in aged female rats. Rats were divided into 4 groups according to age (young vs. aged) and treatment (GBE vs. vehicle). GBE or vehicle was given for 30 d, and a series of behavioral tests were performed. Following behavioral testing, blood samples and brain tissues were obtained for analysis of BDNF, malondialdehyde (MDA), 8-hydroxy-2'-deoxyguanosine (8-OHdG), and glutathione levels, and superoxide dismutase activity. Locomotor activity and anxiety levels were lower in the aged rats. Based on Morris water maze probe trial findings, GBE supplementation increased the number of platform crossings in the aged rats. MDA and 8-OHdG levels were lower in the brain tissue, and BDNF levels were higher in plasma in the rates treated with GBE. Based on these findings, we concluded that GBE supplementation improved cognitive functions by decreasing oxidative damage and increasing the BDNF level in aged female rats.

Effect of Ginkgo biloba extract on lipopolysaccharide-induced anhedonic depressive-like behavior in male rats

The peripheral administration of lipopolysaccharide (LPS) induces depressive-like behavior. Anhedonia is a core symptom of depression, defined as a loss of the capacity to experience pleasure. The present study used the sucrose preference test to investigate the influence of Ginkgo biloba extract (EGb 761) on LPS-induced anhedonia in male rats. The animals were randomly divided into four groups: (I) vehicle + saline, (II) vehicle + LPS, (III) EGb 761 + saline, and (IV) EGb 761 + LPS. Saline or LPS (100 µg/kg) was administered intraperitoneally 2 h before the sucrose preference test. Sucrose consumption was recorded 2, 4, 6, 13, and 24 h after 100 µg/kg of LPS or saline injection in the dark phase of the light/dark cycle. Dopamine and serotonin levels in the nucleus accumbens were measured. Our results indicated that the vehicle + LPS group exhibited a significant decrease in sucrose intake compared with the vehicle + saline group. The EGb 761 + LPS group showed more sucrose and food consumption than the vehicle + LPS group. Additionally, compared with the EGb 761 + LPS group, the vehicle + LPS group had less dopamine levels in the nucleus accumbens. Treatment with EGb 761 had no effect on water intake. Our results suggest that EGb 761 may be useful for reducing anhedonic depressive-like behavior.

Natural polyphenols in the management of major depression

INTRODUCTION

Natural polyphenols, the non-essential micronutrients, found in array of plant products, are known to affect various physiological and biochemical functions in the body. Studies have shown the protective effect of these polyphenols in different neurological and mental disorders. These polyphenols modulate monoaminergic neurotransmission in the brain and thus possess antidepressant-like activity at least in animal models of depression.

AREAS COVERED

The present review discusses the use of these natural polyphenols in the treatment of major depression. The review article discusses the antidepressant potential of some important polyphenols such as amentoflavone, apigenin, chlorogenic acid, curcumin, ferulic acid, hesperidin, rutin, quercetin, naringenin, resveratrol, ellagic acid, nobiletin and proanthocyanidins. The mechanism of action of these polyphenols in the treatment of major depression is also discussed in detail.

EXPERT OPINION

There is an exciting prospect in the discovery of natural polyphenols as therapeutic agents in the treatment of major depression.

Evaluation of the inhibitory effects of quercetin-related flavonoids and tea catechins on the monoamine oxidase-A reaction in mouse brain mitochondria

Quercetin, a typical dietary flavonoid, is thought to exert antidepressant effects by inhibiting the monoamine oxidase-A (MAO-A) reaction, which is responsible for regulation of the metabolism of the neurotransmitter 5-hydroxytryptamine (5-HT) in the brain. This study compared the MAO-A inhibitory activity of quercetin with those of O-methylated quercetin (isorhamnetin, tamarixetin), luteolin, and green tea catechins ((-)-epicatechin, (-)-epicatechin gallate, (-)-epigallocatechin, and (-)-epigallocatechin gallate) by measuring the formation of the oxidative deamination product of 5-HT, 5-hydroxyindole aldehyde (5-HIAL), in mouse brain mitochondria. Quercetin was inferior to luteolin in the inhibition of MAO-A activity, whereas isorhamnetin, tamarixetin, and tea catechins scarcely exerted inhibitory activity. Quercetin did not affect MAO-A activity in mouse intestinal mitochondria, indicating that it does not evoke side effects on the metabolism of dietary monoamines in the gut. These data suggest that quercetin is a weak (but safe) MAO-A inhibitor in the modulation of 5-HT levels in the brain.

Effects of ethanolic extract of pine needles (Pinus eldarica Medw.) on reserpine-induced depression-like behavior in male Wistar rats

Background:

In this study, the antidepressant activity of ethanolic extract of Pinus eldarica Medw needles was assessed using forced swimming test (FST) in rats.

Materials and Methods:

Male Wistar rats were randomly divided into six Groups and treated as follows: first group was received only reserpine (6 mg/kg, i.p.), second group was received reserpine (6 mg/kg, i.p.) and imipramine (10 mg/kg, i.p.), three experimental groups received reserpine (6 mg/kg, i.p.) and three doses of pine needle extract (100, 300, and 500 mg/kg, p.o.) respectively and the final group (control group) received only vehicle (5% DMSO, i.p.).

Results:

Acute oral administration of ethanolic extract of P. eldarica Medw needles at a dosage of 300 mg/kg reduced reserpine-induced increase in immobility time in the FST, demonstrating an antidepressant effect in the FST. Additionally, extract treatment did not modify the ambulation and rearing evaluated in open field test, indicating that antidepressant effect found in the forced swimming test was not based on the stimulation of locomotor activity.

Conclusion:

These results indicate that ethanolic extract of Pinus eldarica needles possesses an antidepressant activity.

Antidepressant-Like Effect of Tagetes lucida Cav. Extract in Rats: Involvement of the Serotonergic System

It has been demonstrated that the decoction of the aerial parts of Tagetes lucida Cav. produces an antidepressant effect during the forced swimming test (FST) in rats. The aim of this study was to evaluate the effect of different organic extracts and one aqueous extract of the aerial parts of T. lucida on the FST. In addition, the possible involvement of the serotonergic system in the antidepressant-like effect of T. lucida in the FST was evaluated, as was its potential toxicological effect. The different extracts of T. lucida (methanol, hexane, dichloromethane and aqueous, 10 and 50 mg/kg), as well as fluoxetine (FLX, 5 mg/kg), were administered per os (p.o.) to rats for 14 days. All animals were subjected to the FST. Only the aqueous extract of T. lucida at a dose of 50 mg/kg significantly reduced immobility behavior and increased swimming in the FST, similar to FLX. Later, the aqueous extract of T. lucida (50mg/kg) was administered for 1, 7 and 14 days. An antidepressant effect was observed after 7 days of treatment. To evaluate the participation of the serotoninergic system, the animals were pretreated with PCPA, an inhibitor of serotonin synthesis (100 mg/kg/day for 4 consecutive days). The animals were treated with the aqueous extract of T. lucida (50 mg/kg) and FLX (5 mg/kg) 24 h after the final injection and were then subjected to the FST. Pretreatment with PCPA inhibited the antidepressant effect of both T. lucida and FLX. Finally, T. lucida was administered p.o. and intraperitoneal route to evaluate its acute toxicological effect. The aqueous extract of T. lucida, administered p.o., did not produce lethality or any significant changes in behavior. In conclusion, the aqueous extract of T. lucida manifested an antidepressant-like effect in the FST mediated by the serotonergic system, with no adverse effects when administered p.o.

N-palmitoylethanolamide, an endocannabinoid, exhibits antidepressant effects in the forced swim test and the tail suspension test in mice

The antidepressant-like effects of N-palmitoylethanolamide (PEA), a putative endocannabinoid, was investigated in mice using the tail suspension test (TST) and the forced swimming test (FST). In TST, PEA (10, 20, and 40 mg/kg) produced a statistically significant reduction in immobility (50, 32, and 34%, respectively, vs. the control group), whereas fluoxetine (20 mg/kg) reduced immobility by 38%. In FST, PEA (5, 10, and 20 mg/kg) produced a statistically significant reduction in immobility (15, 21, and 36%, respectively), whereas fluoxetine (20 mg/kg) reduced immobility by 18%. Moreover, PEA (20 mg/kg) did not significantly change motor activity in a spontaneous behavioral test. In conclusion, PEA (dose range of 5-40 mg/kg) administered orally reduced immobility in TST and FST, comparable to the antidepressant effect of fluoxetine, and had no effect on spontaneous activity in mice.

Accumulation of orally administered quercetin in brain tissue and its antioxidative effects in rats

Quercetin is widely distributed in vegetables and herbs and has been suggested to act as a neuroprotective agent. Here, we demonstrate that quercetin can accumulate enough to exert biological activity in rat brain tissues. Homogenates of perfused rat brain without detectable hemoglobin contaminants were treated with β-glucuronidase/sulfatase and the released quercetin and its methylated form were analyzed using high-performance liquid chromatography (HPLC) with three different detection methods. Both quercetin and the methylated form were detected in the brain of quercetin-administered rats using HPLC-UV and HPLC with electrochemical detection and were further identified using HPLC-tandem mass spectrometry. Oral administration of quercetin (50mg/kg body wt) attenuated the increased oxidative stress in the hippocampus and striatum of rats exposed to chronic forced swimming. The possible transport of quercetin derivatives into the brain tissue was reproduced in vitro by using a rat brain capillary endothelial cell line, a model of the blood-brain barrier. These results show that quercetin could be a potent nutrient that can access the brain and protect it from disorders associated with oxidative stress.

Antidepressant-like and neuroprotective effects of Aloysia gratissima: investigation of involvement of L-arginine-nitric oxide-cyclic guanosine monophosphate pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Aloysia gratissima (Gill. et Hook) Tronc. (Verbenaceae) is used traditionally for the treatment of headache, bronchitis, and nervous systems disorders including depression.

AIM OF THE STUDY

To investigate the antidepressant-like and neuroprotective effects of Aloysia gratissima aqueous extract (AE) and the involvement of l-arginine-nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) pathway.

MATERIALS AND METHODS

The antidepressant-like effect of AE was evaluated through behavioral despair in forced swimming test (FST) and tail suspension test (TST). Swiss albino mice were treated by oral route and after 1h were analyzed the time of immobility in the FST and TST. In addition, the neuroprotective effect of AE against glutamate excitotoxicity was evaluate through cell viability of hippocampal slices, phosphorylation of Akt, and the immunocontent of inducible oxide nitric synthase (iNOS) were investigated by western blotting.

RESULTS

The immobility time in the FST and TST were reduced by AE (100-1000 and 10-300 mg/kg, respectively). The antidepressant-like effect of AE in the TST was prevented by the pretreatment with N-methyl-d-aspartate (NMDA), l-arginine or sildenafil. The subeffective dose of AE produced a synergistic antidepressant-like effect with MK-801 (an antagonist of NMDA receptor), methylene blue, l-NNA (an inhibitor of NO synthase) or ODQ (an inhibitor of soluble guanylate cyclase). In ex vivo experiments, pretreatment with AE prevented the loss of cell viability induced by glutamate, thus affording neuroprotection. Glutamate toxicity caused a decreased Akt phosphorylation and an increased iNOS expression.

CONCLUSIONS

The present study provides convincing evidence of neuroprotection and the involvement of the l-arginine-NO-cGMP pathway in the antidepressant-like effect of AE. Therefore, AE could be of potential interest for the treatment of depressive disorders and neurological conditions associated with glutamate excitotoxicity.

Antidepressants are a rational complementary therapy for the treatment of Alzheimer's disease

There is a high prevalence rate (30-50%) of Alzheimer's disease (AD) and depression comorbidity. Depression can be a risk factor for the development of AD or it can be developed secondary to the neurodegenerative process. There are numerous documented diagnosis and treatment challenges for the patients who suffer comorbidity between these two diseases. Meta analysis studies have provided evidence for the safety and efficacy of antidepressants in treatment of depression in AD patients. Preclinical and clinical studies show the positive role of chronic administration of selective serotonin reuptake inhibitor (SSRI) antidepressants in hindering the progression of the AD and improving patient performance. A number of clinical studies suggest a beneficial role of combinatorial therapies that pair antidepressants with FDA approved AD drugs. Preclinical studies also demonstrate a favorable effect of natural antidepressants for AD patients. Based on the preclinical studies there are a number of plausible antidepressants effects that may modulate the progression of AD. These effects include an increase in neurogenesis, improvement in learning and memory, elevation in the levels of neurotrophic factors and pCREB and a reduction of amyloid peptide burden. Based on this preclinical and clinical evidence, antidepressants represent a rational complimentary strategy for the treatment of AD patients with depression comorbidity.

Anti-depressant natural flavonols modulate BDNF and beta amyloid in neurons and hippocampus of double TgAD mice

Increasing evidence suggests that depression may be both a cause and consequence of neurological disorders such as Alzheimer's disease (AD), and that anti-depressants could provide an alternative strategy to current AD therapies. Association of side effect and herbal-drug interaction with conventional anti-depressant and St. John's wort warrant investigating new anti-depressant drugs. Anti-depressant effects of ginkgo biloba extract (EGb 761) have been demonstrated in animal models of depression and in human volunteers. We report here that ginkgo flavonols quercetin and kaempferol stimulates depression-related signaling pathways involving brain-derived neurotrophic factor BDNF/phosphorylation of cyclic AMP response element binding protein CREB/postsynaptic density proteins PSD95, and reduces amyloid-beta peptide (Abeta) in neurons isolated from double transgenic AD mouse (TgAPPswe/PS1e9). In addition, enhanced BDNF expression and reduction of Abeta oligomers was confirmed in hippocampus of the double transgenic mice administered with flavonol, which correlates with cognitive improvement behaviors in these mice. The present results suggest that stimulating BDNF and reducing Abeta toxicity by natural flavonols provide a therapeutic implication for treatment of AD.

Antidepressant-like effect of the extract of Rosmarinus officinalis in mice: involvement of the monoaminergic system

Rosemary, Rosmarinus officinalis L. (Labiatae) has several therapeutic applications in folk medicine in curing or managing a wide range of diseases, including depression. In this study, the effect of the hydroalcoholic extract of the stems and leaves of this plant was investigated in two behavioral models, the forced swimming test (FST) and tail suspension test (TST) in mice. The extract of R. officinalis produced an antidepressant-like effect, since the acute treatment of mice with the extract by p.o. route significantly reduced the immobility time in the FST (100 mg/kg) and TST (10-100 mg/kg), as compared to a control group, without accompanying changes in ambulation in the open-field test. Moreover, the repeated administration (14 days) of the hydroalcoholic extract of R. officinalis by p.o. route also produced an antidepressant-like effect in the TST (100-300 mg/kg). The pretreatment of mice with p-chlorophenylalanine (PCPA, 100 mg/kg, i.p., an inhibitor of serotonin synthesis, for 4 consecutive days), NAN-190 (0.5 mg/kg, i.p., a 5-HT(1A) receptor antagonist), ketanserin (5 mg/kg, i.p., a 5-HT(2A) receptor antagonist), 1-(m-chlorophenyl) biguanide (mCPBG, 10 mg/kg, i.p., a 5-HT(3) receptor agonist), prazosin (1 mg/kg, i.p., an alpha(1-)adrenoceptor antagonist), SCH23390 (0.05 mg/kg, s.c., a dopamine D(1) receptor antagonist) or sulpiride (50 mg/kg, i.p., a dopamine D(2) receptor antagonist), but not yohimbine (1 mg/kg, i.p., an alpha(2-)adrenoceptor antagonist) was able to reverse the anti-immobility effect of the extract (10 mg/kg, p.o.) in the TST. The combination of MDL72222, (0.1 mg/kg, i.p., a 5-HT(3) receptor antagonist) with a sub-effective dose of the extract of R. officinalis (1 mg/kg, p.o.) produced an anti-immobility effect in the TST. The results suggest that the antidepressant action of the extract of R. officinalis is mediated by an interaction with the monoaminergic system and that this plant should be further investigated as an alternative therapeutic approach for the treatment of depression.

Suppressive effect of quercetin on acute stress-induced hypothalamic-pituitary-adrenal axis response in Wistar rats

The flavonoid quercetin is considered to have beneficial effects on human health. We recently have shown that quercetin-enriched foods reduced the duration of immobility time in a rat forced swimming test, indicating that dietary quercetin is promising as an antidepressant-like factor, whereas its mechanism of action is poorly understood. The aim of this study is to investigate the effects of quercetin on water immersion-restraint (WIR), stress-induced hypothalamic-pituitary-adrenal (HPA) axis activation, which is a major component of stress response and plays an important role in the pathology of depression. Quercetin administration to rats significantly suppressed WIR stress-induced increase of plasma corticosterone and adrenocorticotropic hormone levels as well as the mRNA expression of corticotropin-releasing factor (CRF) in the hypothalamic region. In addition, quercetin modulated the DNA binding activities of glucocorticoid receptor and phosphorylated cyclic adenosine 3',5'-monophosphate (cAMP) response element binding protein as well as the phosphorylation of extracellular signal-regulated kinase 1/2 in the hypothalamic region, all of which are known to regulate the expression of CRF mRNA. Taken together, these results suggest that dietary quercetin attenuates the HPA axis activation by the suppression of the CRF mRNA expression.

Different profiles of quercetin metabolites in rat plasma: comparison of two administration methods

The bioavailability of polyphenols in human and rodents has been discussed regarding their biological activity. We found different metabolite profiles of quercetin in rat plasma between two administration procedures. A single intragastric administration (50 mg/kg) resulted in the appearance of a variety of metabolites in the plasma, whereas only a major fraction was detected by free access (1% quercetin). The methylated/non-methylated metabolites ratio was much higher in the free access group. Mass spectrometric analyses showed that the fraction from free access contained highly conjugated quercetin metabolites such as sulfo-glucuronides of quercetin and methylquercetin. The metabolite profile of human plasma after an intake of onion was similar to that with intragastric administration in rats. In vitro oxidation of human low-density lipoprotein showed that methylation of the catechol moiety of quercetin significantly attenuated the antioxidative activity. These results might provide information about the bioavailability of quercetin when conducting animal experiments.

Antidepressant-like effect of liquiritin from Glycyrrhiza uralensis in chronic variable stress induced depression model rats

Many flavonoids extracted from nature plants have been reported to exert antidepressant-like effect in animal studies. The present study was designed to observe the effects of liquiritin, a flavone compound derived from Glycyrrhiza uralensis, on the behaviors of chronic variable stress induced depression model rats and to explore the possible association between its antidepressant-like effect and antioxidative activity by measuring erythrocyte superoxide dismutase (SOD) activity and plasma malondialdehyde (MDA) level of the experimental animals. With the exposure to stressor once daily for consecutive 5 weeks, liquiritin and a positive control drug fluoxetine were administered via gastric intubation to rats once daily for consecutive 3 weeks from the 3rd week. The results showed that CVS reduced open-field activity and sucrose consumption significantly, but increased immobility time in forced swimming test. Treatment of liquiritin could effectively reverse alteration in immobility time and sucrose consumption but did not show significant effect on open-field activity. Moreover, liquiritin could increase SOD activity, inhibit lipid peroxidation, and lessen production of MDA, while fluoxetine did not. In conclusion, the present study demonstrated a potential antidepressant-like effect of liquiritin treatment on chronic variable stress induced depression model rats, which might be related to defense of liquiritin against oxidative stress.

Complementary medicine for psychiatric disorders in children and adolescents

PURPOSE OF REVIEW

To examine recent empirical studies of herbal and dietary treatments for psychiatric disorders in children and adolescents.

RECENT FINDINGS

Very few quality studies into the use of omega-3 fatty acids, St John's wort, dietary manipulations, kava, gingko and lemon balm in managing psychiatric disorders have been conducted in children and adolescents.

SUMMARY

A number of herbal treatments show promise, but much more empirical research is required to establish their efficacy in the paediatric population.

Constituents from leaves of Apocynum venetum L

An analysis using HPLC-MS revealed that an extract from dried leaves of Apocynum venetum L. contained more than 15 kinds of phenolic constituents. Two malonated flavonol glycosides were further isolated, and their structures were determined to be quercetin 3-O-(6''-O-malonyl)-beta-D-glucoside (1) and quercetin 3-O-(6''-O-malonyl)-beta-D-galactoside (2) by NMR spectroscopic analysis. This is the first report describing the isolation of these malonated flavonol glycosides from A. venetum L. Both glycosides showed strong scavenging activity against 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical.