Serotonergic and noradrenergic systems are implicated in the antidepressant-like effect of ursolic acid in mice

Biomarker triterpenoids of Centella asiatica as potential antidepressant agents: Combining in vivo and in silico studies

Although there are various treatments available for depression, some patients may experience resistance to treatment or encounter adverse effects. Centella asiatica (C. asiatica) is an ancient medicinal herb used in Ayurvedic medicine for its rejuvenating, neuroprotective and psychoactive properties. This study aims to explore the antidepressant-like effects of the major constituents found in C. asiatica, i.e., asiatic acid, asiaticoside, madecassic acid, and madecassoside at three doses (1.25, 2.5, and 5 mg/kg, i.p), on the behavioural and cortisol level of unpredictable chronic stress (UCS) zebrafish model. Based on the findings from the behavioural study, the cortisol levels in the zebrafish body after treatment with the two most effective compounds were measured using enzyme-linked immunosorbent assay (ELISA). Furthermore, a molecular docking study was conducted to predict the inhibitory impact of the triterpenoid compounds on serotonin reuptake. The in vivo results indicate that madecassoside (1.25, 2.5, and 5 mg/kg), asiaticoside and asiatic acid (5 mg/kg) activated locomotor behaviour. Madecassoside at all tested doses and asiaticoside at 2.5 and 5 mg/kg significantly decreased cortisol levels compared to the stressed group, indicating the potential regulation effect of madecassoside and asiaticoside on the hypothalamic-pituitary-adrenal axis overactivity. This study highlights the potential benefits of madecassoside and asiaticoside in alleviating depressive symptoms through their positive effects on behaviour and the hypothalamic-pituitary-adrenal (HPA)- axis in a chronic unpredictable stress zebrafish model. Furthermore, the in silico study provided additional evidence to support these findings. These promising results suggest that C. asiatica may be a valuable and cost-effective therapeutic option for depression, and further research should be conducted to explore its potential benefits.

Ursolic acid inhibits the synaptic release of glutamate and prevents glutamate excitotoxicity in rats

The present study evaluated the effect of ursolic acid, a natural pentacyclic triterpenoid, on glutamate release in rat cortical nerve terminals (synaptosomes) and its neuroprotection in a kainic acid-induced excitotoxicity rat model. In cortical synaptosomes, ursolic acid produced a concentration-dependent inhibition of evoked glutamate release with a half-maximum inhibition of release value of 9.5 μM, and calcium-free medium and the P/Q -type Ca2+ channel blocker, ω-agatoxin IVA, but not ω-conotoxin GVIA, an N-type Ca2+ channel blocker, prevented the ursoloic acid effect. The molecular docking study indicated that ursolic acid interacted with P/Q-type Ca2+ channels. Ursolic acid also significantly decreased the depolarization-induced activation of Ca2+/calmodulin-dependent protein kinase II (CaMKII) and the subsequent phosphorylation of synapsin I, and the ursolic acid effect on evoked glutamate release was inhibited by the CaMKII inhibitor KN 62 in synaptosomes. In addition, in rats that were intraperitoneally injected with ursolic acid 30 min before kainic acid intraperitoneal injection, cortical neuronal degeneration was attenuated. This effect of ursolic acid in the improvement of kainic acid-induced neuronal damage was associated with the reduction of kainic acid-induced glutamate increase in the cortex of rats; this was characterized by the reduction of glutamate and glutaminase levels and elevation of glutamate dehydrogenase, glutamate transporter 1, glutamate-aspartate transporter, and glutamine synthetase protein levels. These results suggest that ursolic acid inhibits glutamate release from cortical synaptosomes by decreasing P/Q-type Ca2+ channel activity and subsequently suppressing CaMKII and exerts a preventive effect against glutamate neurotoxicity by controlling glutamate levels.

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.

Therapeutic potential and novel formulations of ursolic acid and its derivatives: an updated review

Plants produce biologically active metabolites that have been utilised to cure a variety of severe and persistent illnesses. There is a possibility that understanding how these bioactive molecules work would allow researchers to come up with better treatments for diseases including malignancy, cardiac disease and neurological disorders. A triterpene called ursolic acid (UA) is a pentacyclic prevalent triterpenoid found in fruits, leaves, herbs and blooms. The biological and chemical aspects of UA, as well as their presence, plant sources and biosynthesis, and traditional and newer technologies of extraction, are discussed in this review. Because of its biological function in the creation of new therapeutic techniques, UA is a feasible option for the evolution and medical management of a wide range of medical conditions, including cancer and other life threatening diseases. Despite this, the substance's poor solubility in aquatic environments makes it unsuitable for medicinal purposes. This hurdle was resolved in many different ways. The inclusion of UA into various pharmaceutical delivery approaches was found to be quite effective in this respect. This review also describes the properties of UA and its pharmacokinetics, as well as therapeutic applications of UA for cancer, inflammatory and cardiovascular diseases, in addition to its anti-diabetic, immunomodulatory, hepatoprotective and anti-microbial properties. Some of the recent findings related to novel nano-sized carriers as a delivery system for UA and the patents related to the applications of UA and its various derivatives are covered in this review. The analytical study of UA, oleanolic acid and other phytoconstituents by UV, HPLC, high-performance thin-layer chromatography and gas chromatography is also discussed. In the future, UA could be explored in vivo using various animal models and, in addition, the regulatory status regarding UA needs to be explored. © 2023 Society of Chemical Industry.

Oleanolic acid and ursolic acid: therapeutic potential in neurodegenerative diseases, neuropsychiatric diseases and other brain disorders

Brain disorders such as neurodegenerative diseases and neuropsychiatric diseases have become serious threatens to human health and quality of life. Oleanolic acid (OA) and ursolic acid (UA) are pentacyclic triterpenoid isomers widely distributed in various plant foods and Chinese herbal medicines. Accumulating evidence indicates that OA and UA exhibit neuroprotective effects on multiple brain disorders. Therefore, this paper reviews researches of OA and UA on neurodegenerative diseases, neuropsychiatric diseases and other brain disorders including ischemic stroke, epilepsy, etc, as well as the potential underlying molecular mechanisms.

Natural Phytochemicals for the Treatment of Major Depressive Disorder: A Mini-Review of Pre- and Clinical Studies

Major Depressive Disorder (MDD) is a common mental illness that causes significant disability and declining quality of life. An overlap of multiple factors can be involved in the pathophysiology of this mood disorder, including increased inflammation and oxidative stress, change in neurotransmitters, decreased brain-derived neurotrophic factor (BDNF), activation of the hypothalamicpituitary- adrenal (HPA) axis, and changes in the microbiota-gut-brain axis. Although the classic treatment for MDD is safe, it is far from ideal, with delay to start the best clinic, side effects, and a large number of non-responses or partial-responses. Therefore, other alternatives are being studied to improve depressive symptoms, and, among them, the role of phytochemicals in food stands out. This mini-review will discuss the main phytochemicals present in foods with clinical and preclinical studies showing benefits for MDD treatment. In addition, the main mechanisms of action that are being proposed for each of these compounds will be addressed.

Involvement of serotonergic neurotransmission in the antidepressant-like effect elicited by cholecalciferol in the chronic unpredictable stress model in mice

Cholecalciferol deficiency has been associated with stress-related psychiatric disorders, particularly depression. Therefore, the present study investigated the antidepressant-like effect of cholecalciferol in female mice and the possible role of the serotonergic system in this response. The ability of cholecalciferol to elicit an antidepressant-like effect and to modulate serotonin levels in the hippocampus and prefrontal cortex of mice subjected to chronic unpredictable stress (CUS) was also investigated. The administration of cholecalciferol (2.5, 7.5, and 25 µg/kg, p.o.) for 7 days, similar to fluoxetine (10 mg/kg, p.o., serotonin reuptake inhibitor), reduced the immobility time in the tail suspension test, without altering the locomotor performance in the open-field test. Moreover, the administration of p-chlorophenylalanine methyl ester (PCPA - 100 mg/kg, i.p., for 4 days, a selective inhibitor of tryptophan hydroxylase, involved in the serotonin synthesis) abolished the antidepressant-like effect of cholecalciferol and fluoxetine in the tail suspension test, demonstrating the involvement of serotonergic system. Additionally, CUS protocol (21 days) induced depressive-like behavior in the tail suspension test and decreased serotonin levels in the prefrontal cortex and hippocampus of mice. Conversely, the administration of cholecalciferol and fluoxetine in the last 7 days of CUS protocol completely abolished the stress-induced depressive-like phenotype. Cholecalciferol was also effective to abrogate CUS-induced reduction on serotonin levels in the prefrontal cortex, but not in the hippocampus. Our results indicate that cholecalciferol has an antidepressant-like effect in mice by modulating the serotonergic system and support the assumption that cholecalciferol may have beneficial effects for the management of depression.

Natural Products for the Treatment of Post-stroke Depression

Post-stroke depression (PSD) is the most frequent and important neuropsychiatric consequence of stroke. It is strongly associated with exacerbated deterioration of functional recovery, physical and cognitive recoveries, and quality of life. However, its mechanism is remarkably complicated, including the neurotransmitters hypothesis (which consists of a monoaminergic hypothesis and glutamate-mediated excitotoxicity hypothesis), inflammation hypothesis, dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis, and neurotrophic hypothesis and neuroplasticity. So far, the underlying pathogenesis of PSD has not been clearly defined yet. At present, selective serotonin reuptake inhibitors (SSRIs) have been used as the first-line drugs to treat patients with PSD. Additionally, more than SSRIs, a majority of the current antidepressants complied with multiple side effects, which limits their clinical application. Currently, a wide variety of studies revealed the therapeutic potential of natural products in the management of several diseases, especially PSD, with minor side effects. Accordingly, in our present review, we aim to summarize the therapeutic targets of these compounds and their potential role in-clinic therapy for patients with PSD.

Role of heme oxygenase-1 in the antidepressant-like effect of ursolic acid in the tail suspension test

OBJECTIVES

This study investigated the involvement of heme oxygenase-1 (HO-1) in the antidepressant-like effects of ursolic acid (UA), a plant-derived compound with neuroprotective and antidepressant-like properties.

METHODS

Mice received intracerebroventricular injections of zinc protoporphyrin IX (ZnPP) or cobalt protoporphyrin IX (CoPP) to inhibit or induce HO-1, respectively, together with effective (0.1 mg/kg, p.o.) or sub-effective (0.01 mg/kg, p.o.) doses of UA or fluoxetine (10 mg/kg, p.o.). Immobility time was assessed using the tail suspension test (TST) and the ambulatory behaviour with the open field test. HO-1 immunocontent was evaluated in mice hippocampus and prefrontal cortex.

KEY FINDINGS

ZnPP prevented the anti-immobility effects of UA and fluoxetine. Combined treatment with a sub-effective dose of CoPP and UA synergistically exerted antidepressant-like effects in the TST. Acute administration of UA or CoPP, but not fluoxetine, increased the HO-1 immunocontent in the hippocampus. None of the treatments altered the HO-1 immunocontent in the prefrontal cortex.

CONCLUSIONS

In conclusion, this work shows that increased hippocampal HO-1 content and activity mediate the antidepressant-like effect of UA in the TST.

Therapeutic Potential of Ursolic Acid in Cancer and Diabetic Neuropathy Diseases

Ursolic acid (UA) is a pentacyclic triterpenoid frequently found in medicinal herbs and plants, having numerous pharmacological effects. UA and its analogs treat multiple diseases, including cancer, diabetic neuropathy, and inflammatory diseases. UA inhibits cancer proliferation, metastasis, angiogenesis, and induced cell death, scavenging free radicals and triggering numerous anti- and pro-apoptotic proteins. The biochemistry of UA has been examined broadly based on the literature, with alterations frequently having been prepared on positions C-3 (hydroxyl), C12-C13 (double bonds), and C-28 (carboxylic acid), leading to several UA derivatives with increased potency, bioavailability and water solubility. UA could be used as a protective agent to counter neural dysfunction via anti-oxidant and anti-inflammatory effects. It is a potential therapeutic drug implicated in the treatment of cancer and diabetic complications diseases provide novel machinery to the anti-inflammatory properties of UA. The pharmacological efficiency of UA is exhibited by the therapeutic theory of one-drug → several targets → one/multiple diseases. Hence, UA shows promising therapeutic potential for cancer and diabetic neuropathy diseases. This review aims to discuss mechanistic insights into promising beneficial effects of UA. We further explained the pharmacological aspects, clinical trials, and potential limitations of UA for the management of cancer and diabetic neuropathy diseases.

Influence of Smallanthus sonchifolius (Yacon) on the Activity of Antidepressant Drugs in Mice

Depression is one of the most common mental disorders in the world that negatively affects the daily functioning of patients. Numerous studies are currently being conducted to examine the antidepressant potential of innovative synthetic compounds and herbal substances. Yacon, Smallantchus sonchifolius, belongs to plants with numerous health-beneficial properties. Yacon-based products are regarded as a functional food. In our study, we attempted to check whether administration of Yacon tuber extract would have an antidepressant effect in the forced swim test (FST) in mice and whether its intake could influence the activity of conventional antidepressant drugs with different mechanisms of action, i.e., imipramine hydrochloride, fluoxetine hydrochloride, and reboxetine mesylate. The spontaneous locomotor activity of the tested mice was also investigated to eliminate any false-positive results. We demonstrated that an intragastric administration of the Yacon tuber extract at a dose of 100 mg/kg induced the antidepressant-like behavior in the FST in mice and that a combined administration of the sub-effective doses of the Yacon extract (50 mg/kg) with imipramine hydrochloride (7.5 mg/kg), fluoxetine hydrochloride (20 mg/kg), or reboxetine mesylate (5 mg/kg) significantly reduced the immobility time of animals in this behavioral test. The obtained results were not affected by the increased locomotor activity of the tested subjects. In conclusion, our findings suggest that Yacon tuber extract is promising as an alternative mood-improving product since it possesses an antidepressant potential and it can acts synergistically with conventional antidepressant drugs.

Ursolic acid enhances stress resistance, reduces ROS accumulation and prolongs life span in C. elegans serotonin-deficient mutants

INTRODUCTION

Depression and anxiety disorders contribute to the global disease burden. Ursolic acid (UA), a natural compound present in many vegetables, fruits and medicinal plants, was tested in vivo for its effect on (1) enhancing resistance to stress and (2) its effect on life span.

METHODS

The compound was tested for its antioxidant activity in C. elegans. Stress resistance was tested in the heat and osmotic stress assay. Additionally, the influence on normal life span was examined. RT-PCR was used to assess possible serotonin targets.

RESULTS

UA prolonged the life span of C. elegans. Additionally, UA significantly lowered reactive oxygen species (ROS). Molecular docking studies, PCR analysis and microscale thermophoresis (MST) supported the results that UA acts through serotonin receptors to enhance stress resistance.

DISCUSSION

Considering the urgent need for new and safe medications in the treatment of depression and anxiety disorders, our results indicate that UA may be a promising new drug candidate.

Ursolic acid abrogates depressive-like behavior and hippocampal pro-apoptotic imbalance induced by chronic unpredictable stress

Emerging evidence has shown that ursolic acid exerts antidepressant-like effects, however, its ability to elicit an antidepressant-like response in rodents subjected to stress model that mimics behavioral and neurochemical alterations found in depression remains to be determined. Thus, this study investigated the possible antidepressant-like effect of ursolic acid in mice subjected to chronic unpredictable stress (CUS) for 14 days, and whether this effect could be associated with the modulation of serum corticosterone levels and hippocampal Bcl-2/Bax mRNA expression. Our results indicated that CUS induced a depressive-like behavior, as demonstrated by an increase in the immobility time and latency to first grooming in the tail suspension test and splash test, respectively. Conversely, the repeated administration of ursolic acid (0.1 mg/kg, p.o.) or fluoxetine (10 mg/kg, p.o.) in the last 7 days of CUS completely prevented CUS-induced behavioral alterations, suggesting an antidepressant-like effect. Additionally, CUS significantly increased the mRNA expression of Bax (pro-apoptosis marker), but not Bcl-2 (anti-apoptosis marker) in the hippocampus. Moreover, reduced hippocampal mRNA expression of Bcl-2/Bax ratio was detected in CUS-exposed mice. Ursolic acid, but not fluoxetine, prevented CUS-induced increase in the expression of Bax, but both ursolic acid and fluoxetine prevented CUS-induced reduction on Bcl-2/Bax ratio. Furthermore, neither CUS nor treatments with ursolic acid or fluoxetine altered serum corticosterone levels. Our study unveils the ability of ursolic acid to prevent the depressive-like behavior induced by stress and the modulation of Bcl-2/Bax expression could be associated with this response.

Ursolic acid: A systematic review of its pharmacology, toxicity and rethink on its pharmacokinetics based on PK-PD model

Ursolic acid (UA) is a natural pentacyclic triterpenoid compound existing in various traditional Chinese medicinal herbs, and it possesses diverse pharmacological actions and some undesirable adverse effects, even toxicological activities. Due to UA's low solubility and poor bioavailability, and its interaction with gut microbiota after oral administration, the pharmacokinetics of UA remain elusive, leading to obscurity in the pharmacokinetics-pharmacodynamics (PK-PD) profile and relationship for UA. Based on literatures from PubMed, Google Scholar, ResearchGate, Web of Science and Wiley Online Library, with keywords of "pharmacology", "toxicology", "pharmacokinetics", "PK-PD" and "ursolic acid", herein we systematically review the pharmacology and toxicity of UA, and rethink on its pharmacokinetics on the basis of PK-PD model, and seek to delineate the underlying mechanisms for the characteristics of pharmacology and toxicology of UA, and for the pharmacokinetic features of UA particularly from the organ tropism and the interactions between UA and gut microbiota, and lay a solid foundation for development of UA-derived therapeutic agents in clinical settings.

Protective Effects of Ursolic Acid Against Cytotoxicity Induced by Corticosterone: Role of Protein Kinases

Neuronal hippocampal death can be induced by exacerbated levels of cortisol, a condition usually observed in patients with Major depressive disorder (MDD). Previous in vitro and in vivo studies showed that ursolic acid (UA) elicits antidepressant and neuroprotective properties. However, the protective effects of UA against glucocorticoid-induced cytotoxicity have never been addressed. Using an in vitro model of hippocampal cellular death induced by elevated levels of corticosterone, we investigated if UA prevents corticosterone-induced cytotoxicity in HT22 mouse hippocampal derived cells. Concentrations lower than 25 µM UA did not alter cell viability. Co-incubation with UA for 48 h was able to protect HT22 cells from the reduction on cell viability and from the increase in apoptotic cells induced by corticosterone. Inhibition of protein kinase A (PKA), protein kinase C (PKC) and, Ca2+/calmodulin-dependent protein kinase II (CaMKII), but not phosphoinositide 3-kinase(PI3K), by using the pharmacological the inhibitors: H-89, chelerythrine, KN-62, and LY294002, respectively totally abolished the cytoprotective effects of UA. Finally, UA abrogated the reduction in phospho-extracellular signal-regulated kinases 1 and 2 (ERK1/2) but not in phospho-c-Jun kinases induced by corticosterone. These results indicate that the protective effect of UA against the cytotoxicity induced by corticosterone in HT22 cells may involve PKA, PKC, CaMKII, and ERK1/2 activation. The cytoprotective potential of UA against corticosterone-induced cytotoxicity and its ability to modulate intracellular signaling pathways involved in cell proliferation and survival suggest that UA may be a relevant strategy to manage stress-related disorders such as MDD.

Antioxidant and Anti-inflammatory Mechanisms of Neuroprotection by Ursolic Acid: Addressing Brain Injury, Cerebral Ischemia, Cognition Deficit, Anxiety, and Depression

Ursolic acid (UA) is a pentacyclic triterpene which is found in common herbs and medicinal plants that are reputed for a variety of pharmacological effects. Both as an active principle of these plants and as a nutraceutical ingredient, the pharmacology of UA in the CNS and other organs and systems has been extensively reported in recent years. In this communication, the antioxidant and anti-inflammatory axis of UA's pharmacology is appraised for its therapeutic potential in some common CNS disorders. Classic examples include the traumatic brain injury (TBI), cerebral ischemia, cognition deficit, anxiety, and depression. The pharmacological efficacy for UA is demonstrated through the therapeutic principle of one drug → multitargets → one/many disease(s). Both specific enzymes and receptor targets along with diverse pharmacological effects associated with oxidative stress and inflammatory signalling are scrutinised.

Monoaminergic system is implicated in the antidepressant-like effect of hyperoside and protocatechuic acid isolated from Impatiens glandulifera Royle in mice

We have recently demonstrated that the hydroethanolic extracts of Impatiens glandulifera Royle (Balsaminaceae) have antianxiety effect in mice. The present study was aimed to investigate an antidepressant activity of hyperoside (HYP) and protocatechuic acid (PCA), two polyphenols isolated from the aerial parts of this plant, using the forced swimming test (FST) and tail suspension test (TST) in mice. The implication of the monoaminergic system in this effect was assessed and brain-derived neurotrophic factor (BDNF) expression was measured. At doses 1.875, 3.75 and 7.5 mg/kg, HYP and PCA significantly reduced immobility in the FST and TST, without affecting locomotor activity of mice. Pretreatment with p-chlorophenylalanine (PCPA 100 mg/kg, a serotonin synthesis inhibitor) or α-methyl-DL-tyrosine (AMPT 100 mg/kg, a catecholamine synthesis inhibitor) was able to prevent antidepressant-like effect of HYP and PCA (3.75 mg/kg). Sub-effective doses of fluoxetine (5 mg/kg) or reboxetine (2 mg/kg) were capable of potentiating the effect of a sub-effective dose of HYP (0.94 mg/kg) in the FST. Co-administration of sub-effective dose of PCA (0.94 mg/kg) and reboxetine (2 mg/kg) resulted in reducing immobility in the FST. The antidepressant-like effect of HYP and PCA was also prevented by the administration of sulpiride (50 mg/kg), a D2 antagonist. In addition, HYP (3.75 and 7.5 mg/kg) and PCA (7.5 mg/kg) improved the expression of hippocampal BDNF of mice subjected to TST. Altogether, our findings suggest that HYP and PCA exert antidepressant-like effects in mice, which was possibly mediated by monoaminergic system and the upregulation of BDNF level.

Homeostatic cAMP regulation by the RGS7 complex controls depression-related behaviors

Affective disorders arise from abnormal responses of the brain to prolonged exposure to challenging environmental stimuli. Recent work identified the orphan receptor GPR158 as a molecular link between chronic stress and depression. Here we reveal a non-canonical mechanism by which GPR158 exerts its effects on stress-induced depression by the complex formation with Regulator of G protein Signaling 7 (RGS7). Chronic stress promotes membrane recruitment of RGS7 via GPR158 in the medial prefrontal cortex (mPFC). The resultant complex suppresses homeostatic regulation of cAMP by inhibitory GPCRs in the region. Accordingly, RGS7 loss in mice induces an antidepressant-like phenotype and resiliency to stress, whereas its restoration within the mPFC is sufficient to rescue this phenotype in a GPR158-dependent way. These findings mechanistically link the unusual orphan receptor-RGS complex to a major stress mediator, the cAMP system and suggest new avenues for pharmacological interventions in affective disorders.

Ethanol extract of Rehmannia glutinosa exerts antidepressant-like effects on a rat chronic unpredictable mild stress model by involving monoamines and BDNF

The dried roots of Rehmannia glutinosa Libosch. (Scrophulariaceae) are of both medicinal and nutritional importance. Our previous study has found that the 80% ethanol extract of R. glutinosa (RGEE) produced antidepressant-like activities in mouse behavioral despair depression models. However, its mechanisms are still unclear. The present study aimed to observe the antidepressant-like mechanisms of RGEE on a rat chronic unpredictable mild stress (CUMS) model by involving monoaminergic neurotransmitters and brain-derived neurotrophic factor (BDNF). CUMS-stressed rats were orally given RGEE daily (150, 300, and 600 mg/kg) or fluoxetine hydrochloride (FH) for 3 weeks after starting the CUMS procedure. Sucrose preference test was carried out to observe depression-like behavior, and serum and brain tissues were used for neurochemical and fluorescent quantitative reverse transcription PCR analysis. Results demonstrated that CUMS induced depression-like behavior, whereas RGEE and FH administration inhibited this symptom. Furthermore, CUMS caused excessively elevated levels of serum corticosterone (CORT), an index of hypothalamic-pituitary-adrenal (HPA) axis hyperactivity, in a manner attenuated by RGEE and FH administration. RGEE administration also further elevated monoamine neurotransmitters and BDNF levels, up-regulated the mRNA expression of BDNF and tropomyosin-related kinase B (TrkB) in hippocampus of rats suffering CUMS. Together, our findings suggest that RGEE can improve CUMS-evoked depression-like behavior, and indicate its mechanisms may partially be associated with restoring HPA axis dysfunctions, enhancing monoamineergic nervous systems, and up-regulating BDNF and TrkB expression.

Assessment of the Anticonvulsant Potency of Ursolic Acid in Seizure Threshold Tests in Mice

Ursolic acid (UA) is a plant derived compound which is also a component of the standard human diet. It possesses a wide range of pharmacological properties, i.e., antioxidant, anti-inflammatory, antimicrobial and antitumor, which have been used in folk medicine for centuries. Moreover, influence of UA on central nervous system-related processes, i.e., pain, anxiety and depression, was proved in experimental studies. UA also revealed anticonvulsant properties in animal models of epilepsy and seizures. The aim of the present study was to investigate the influence of UA on seizure thresholds in three acute seizure models in mice, i.e., the 6 Hz-induced psychomotor seizure threshold test, the maximal electroshock threshold (MEST) test and the timed intravenous pentylenetetrazole (iv PTZ) infusion test. We also examined its effect on the muscular strength (assessed in the grip strength test) and motor coordination (estimated in the chimney test) in mice. UA at doses of 50 and 100 mg/kg significantly increased the seizure thresholds in the 6 Hz and MEST tests. The studied compound did not influence the seizure thresholds in the iv PTZ test. Moreover, UA did not affect the motor coordination and muscular strength in mice. UA displays only a weak anticonvulsant potential which is dependent on the used seizure model.

Ursolic acid derivatives as potential antidiabetic agents: In vitro, in vivo, and in silico studies

Hit, Lead & Candidate Discovery Protein tyrosine phosphatase 1B (PTP-1B) has attracted interest as a novel target for the treatment of type 2 diabetes, this because its role in the insulin-signaling pathway as a negative regulator. Thus, the aim of current work was to obtain seven ursolic acid derivatives as potential antidiabetic agents with PTP-1B inhibition as main mechanism of action. Furthermore, derivatives 1-7 were submitted in vitro to enzymatic PTP-1B inhibition being 3, 5, and 7 the most active compounds (IC50  = 5.6, 4.7, and 4.6 μM, respectively). In addition, results were corroborated with in silico docking studies with PTP-1B orthosteric site A and extended binding site B, showed that 3 had polar and Van der Waals interactions in both sites with Lys120, Tyr46, Ser216, Ala217, Ile219, Asp181, Phe182, Gln262, Val49, Met258, and Gly259, showing a docking score value of -7.48 Kcal/mol, being more specific for site A. Moreover, compound 7 showed polar interaction with Gln262 and Van der Waals interactions with Ala217, Phe182, Ile219, Arg45, Tyr46, Arg47, Asp48, and Val49 with a predictive docking score of -6.43 kcal/mol, suggesting that the potential binding site could be localized in the site B adjacent to the catalytic site A. Finally, derivatives 2 and 7 (50 mg/kg) were selected to establish their in vivo antidiabetic effect using a noninsulin-dependent diabetes mice model, showing significant blood glucose lowering compared with control group (p < .05).

Ursolic acid affords antidepressant-like effects in mice through the activation of PKA, PKC, CAMK-II and MEK1/2

BACKGROUND

Ursolic acid has been shown to display antidepressant-like effects in mice through the modulation of monoaminergic systems. In this study, we sought to investigate the involvement of signaling pathways on the antidepressant-like effects of ursolic acid.

METHODS

Mice were treated orally with ursolic acid (0.1mg/kg) and, 45min later they received the followings inhibitors by intracerebroventricular route: H-89 (PKA inhibitor, 1μg/mouse), KN-62 (CAMK-II inhibitor, 1μg/mouse), chelerythrine (PKC inhibitor, 1μg/mouse), U0126 (MEK1/2 inhibitor, 5μg/mouse), PD98059 (MEK1/2 inhibitor, 5μg/mouse), wortmannin (PI3K irreversible inhibitor, 0.1μg/mouse) or LY294002 (PI3K inhibitor, 10 nmol/mouse). Immobility time of mice was registered in the tail suspension test (TST).

RESULTS

The anti-immobility effect of ursolic acid in the TST was abolished by the treatment of mice with H-89, KN-62, chelerythrine, U0126 or PD98059, but not with wortmannin or LY294002.

CONCLUSIONS

These results suggest that activation of PKA, PKC, CAMK-II, MEK1/2 may underlie the antidepressant-like effects of ursolic acid.

Therapeutic Potential of Ursolic Acid to Manage Neurodegenerative and Psychiatric Diseases

Ursolic acid is a pentacyclic triterpenoid found in several plants. Despite its initial use as a pharmacologically inactive emulsifier in pharmaceutical, cosmetic and food industries, several biological activities have been reported for this compound so far, including anti-tumoural, anti-diabetic, cardioprotective and hepatoprotective properties. The biological effects of ursolic acid have been evaluated in vitro, in different cell types and against several toxic insults (i.e. 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, amyloid-β peptides, kainic acid and others); in animal models of brain-related disorders (Alzheimer disease, Parkinson disease, depression, traumatic brain injury) and ageing; and in clinical studies with cancer patients and for muscle atrophy. Most of the protective effects of ursolic acid are related to its ability to prevent oxidative damage and excessive inflammation, common mechanisms associated with multiple brain disorders. Additionally, ursolic acid is capable of modulating the monoaminergic system, an effect that might be involved in its ability to prevent mood and cognitive dysfunctions associated with neurodegenerative and psychiatric conditions. This review presents and discusses the available evidence of the possible beneficial effects of ursolic acid for the management of neurodegenerative and psychiatric disorders. We also discuss the chemical features, major sources and potential limitations of the use of ursolic acid as a pharmacological treatment for brain-related diseases.

Computational and biological evidences on the serotonergic involvement of SeTACN antidepressant-like effect in mice

A series of phenylselanyl-1H-1,2,3-triazole-4-carbonitriles with different substituents were screened for their binding affinity with serotonin transporter (SERT) and dopamine transporter (DAT) by docking molecular. 5-(4methoxyphenyl)-1-(2-(phenylselanyl)phenyl)-1H-1,2,3-triazole-4-carbonitrile (SeTACN) exhibited the best conformation with SERT even higher than fluoxetine and serotonin, suggesting a competitive inhibition. SeTACN demonstrated additional affinity to other serotonergic receptors involved in antidepressant effects: 5HT_1a, 5HT_2a and 5HT₃. In another set of experiments, SeTACN led to significant reductions in the immobility time of mice submitted to forced swimming test (FST) in the dose range of 0.1- 20mg/kg, suggesting an antidepressant-like effect. The possible mechanism of action was investigated using serotonergic and dopaminergic antagonists. The antidepressant-like effect of SeTACN (0.1mg/kg i.g.) was prevented by the pretreatment with WAY100635 (a selective 5HT_1a antagonist), ketanserin (a 5HT2_a/c antagonist) and ondansetron (a selective 5ht₃ antagonist), PCPA (an inhibitor of serotonin synthesis) but not with SCH23390 (dopaminergic D₁ antagonist) and sulpiride (D₂ antagonist). Sub-effective dose of fluoxetine was able to potentiate the effects of a sub-effective dose of SeTACN in FST. None of the treatments affected locomotor activity in open field test (OFT). These results together, suggest that the SeTACN antidepressant-like effect is mediate, at least in parts, by serotonergic system.

Radioprotective effect of ursolic acid in radiation-induced impairment of neurogenesis, learning and memory in adolescent BALB/c mouse

The effect of acute irradiation with 5Gy or fractionated exposure with 0.5Gy continuously for 10days (a total dose of 5Gy) was evaluated in an immature BALB/c mouse model. Radioprotective effect of ursolic acid (at 25mg/kg/daily administered 1h after acute or each of fractionated irradiations, and continuously for 30days) was also investigated. We found that both acute and fractionated irradiation at a total dose of 5Gy did not induce any mortality within 30days after exposure to postnatal day 26 (P26) BALB/c mice, but reduced animal weigh gain in the first few weeks. At 90days after irradiation, the weight of animals with acute irradiation was still significantly lower than the control group; no significant difference though was observed for those fractionatedly exposed mice compared to the control group. Behavioral tests indicated that acute irradiation at 5Gy induced deficits in learning and memory in the contextual fear conditioning test. The memory for novel object recognition was also impaired. Similar changes were not observed in mice with fractionated irradiation. Immunohistochemical study demonstrated clearly that acute and fractionated irradiations induced impairment of neurogenesis in the subgranular zone (SGZ) of the dentate gyrus although fractionated exposure induced much lesser loss of newly generated neurons. Ursolic acid administered at 25mg/kg/daily for 30days after irradiation greatly improved acute irradiation-induced deficits in contextual learning and memory and in novel object recognition memory although it exacerbated radiation-induced reduction of neurogenesis in SGZ.

Antidepressive and antinociceptive effects of ethanolic extract and fruticuline A from Salvia lachnostachys Benth leaves on rodents

Objectives

This study investigated the antidepressant and antinociceptive effects of ethanolic extract (SLEE) and pure fruticuline A obtained from Salvia lachnostachys leaves on rats and mice.

Methods

In this study, SLEE (100 mg/kg, p.o. route) was evaluated for its effects on spared nerve injury (SNI) in rats. The animals were submitted to mechanical sensitivity, forced swim (FST) and cold sensitivity tests 10 and 15 days after surgery. SLEE (100 mg/kg, p.o.) and fruticuline A (3 mg/kg, p.o.) were also evaluated with respect to nociceptive behavior induced by formalin. In addition, clonidine-induced depressive-like behavior was also analyzed.

Results

The oral administration of SLEE for up to 15 days and the subcutaneous injection of 10 mg/kg of ketamine (positive control) significantly inhibited SNI-induced mechanical hyperalgesia and decreased immobility in the FST. On the 15th day of oral treatment, SLEE prevented the SNI-induced increase in cold sensitivity. In the formalin test, SLEE and fruticuline A significantly reduced the frequency of paw licking during the first and second phases and decreased the formation of edema. In locomotor analysis (open field test without clonidine treatment), SLEE and fruticuline A did not alter the response. SLEE and fruticuline A significantly attenuated clonidine-induced suppression of spontaneous locomotor activity (squares invaded and licking) and emotionality (grooming and freezing) compared with controls, similar to the naive group.

Conclusion

SLEE exhibits antihyperalgesic, antidepressant, and antinociceptive effects, and fruticuline A appears to be at least partly responsible for the effects of SLEE. Together, these results demonstrate the antidepressive effects of SLEE and fruticuline A and indicate that both derivatives obtained from S. lachnostachys act against spontaneous neuropathic pain.

Subchronic administration of ascorbic acid elicits antidepressant-like effect and modulates cell survival signaling pathways in mice

In this study, we examined the ability of subchronic ascorbic acid administration to produce an antidepressant-like effect in the mouse tail suspension test (TST). Moreover, we investigated the effect of this vitamin on hippocampal and cerebrocortical brain-derived neurotrophic factor (BDNF) immunocontent, phosphorylation of protein kinase B (AKT), extracellular signal-regulated kinase (ERK), p38^MAPK and c-Jun. N-terminal kinase (JNK). Fluoxetine (10 mg/kg, positive control, po) or ascorbic acid (0.1 and 1 mg/kg, po), administered once daily for 21 days, produced a significant antidepressant-like effect in the TST. The significant effects obtained in protein immunocontents were: administration of ascorbic acid at 1 mg/kg induced an increase in AKT phosphorylation in cerebral cortex of mice. Ascorbic acid treatment (1 mg/kg), similar to fluoxetine, decreased hippocampal p38^MAPK but did not alter ERK or JNK phosphorylation. These results extend the data about the antidepressant-like effect of ascorbic acid by exploring, for the first time, the intracellular pathways involved in its antidepressant properties after subchronic administration.

Ursolic acid (UA): A metabolite with promising therapeutic potential

Plants are known to produce a variety of bioactive metabolites which are being used to cure various life threatening and chronic diseases. The molecular mechanism of action of such bioactive molecules, may open up new avenues for the scientific community to develop or improve novel therapeutic approaches to tackle dreadful diseases such as cancer and cardiovascular and neurodegenerative disorders. Ursolic acid (UA) is one among the categories of such plant-based therapeutic metabolites having multiple intracellular and extracellular targets that play role in apoptosis, metastasis, angiogenesis and inflammatory processes. Moreover, the synthetic derivatives of UA have also been seen to be involved in a range of pharmacological applications, which are associated with prevention of diseases. Evidences suggest that UA could be used as a potential candidate to develop a comprehensive competent strategy towards the treatment and prevention of health disorders. The review article herein describes the possible therapeutic effects of UA along with putative mechanism of action.

Endogenous opiates and behavior: 2014

This paper is the thirty-seventh consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2014 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (endogenous opioids and receptors), and the roles of these opioid peptides and receptors in pain and analgesia (pain and analgesia); stress and social status (human studies); tolerance and dependence (opioid mediation of other analgesic responses); learning and memory (stress and social status); eating and drinking (stress-induced analgesia); alcohol and drugs of abuse (emotional responses in opioid-mediated behaviors); sexual activity and hormones, pregnancy, development and endocrinology (opioid involvement in stress response regulation); mental illness and mood (tolerance and dependence); seizures and neurologic disorders (learning and memory); electrical-related activity and neurophysiology (opiates and conditioned place preferences (CPP)); general activity and locomotion (eating and drinking); gastrointestinal, renal and hepatic functions (alcohol and drugs of abuse); cardiovascular responses (opiates and ethanol); respiration and thermoregulation (opiates and THC); and immunological responses (opiates and stimulants). This paper is the thirty-seventh consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2014 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (endogenous opioids and receptors), and the roles of these opioid peptides and receptors in pain and analgesia (pain and analgesia); stress and social status (human studies); tolerance and dependence (opioid mediation of other analgesic responses); learning and memory (stress and social status); eating and drinking (stress-induced analgesia); alcohol and drugs of abuse (emotional responses in opioid-mediated behaviors); sexual activity and hormones, pregnancy, development and endocrinology (opioid involvement in stress response regulation); mental illness and mood (tolerance and dependence); seizures and neurologic disorders (learning and memory); electrical-related activity and neurophysiology (opiates and conditioned place preferences (CPP)); general activity and locomotion (eating and drinking); gastrointestinal, renal and hepatic functions (alcohol and drugs of abuse); cardiovascular responses (opiates and ethanol); respiration and thermoregulation (opiates and THC); and immunological responses (opiates and stimulants).

The effect of Schisandra chinensis extracts on depression by noradrenergic, dopaminergic, GABAergic and glutamatergic systems in the forced swim test in mice

Schisandra chinensis (Turcz.) Baill., as a Chinese functional food, has been widely used in neurological disorders including insomnia and Alzheimer's disease.

Ursolic Acid--A Pentacyclic Triterpenoid with a Wide Spectrum of Pharmacological Activities

Ursolic acid (UA) is a natural terpene compound exhibiting many pharmaceutical properties. In this review the current state of knowledge about the health-promoting properties of this widespread, biologically active compound, as well as information about its occurrence and biosynthesis are presented. Particular attention has been paid to the application of ursolic acid as an anti-cancer agent; it is worth noticing that clinical tests suggesting the possibility of practical use of UA have already been conducted. Amongst other pharmacological properties of UA one can mention protective effect on lungs, kidneys, liver and brain, anti-inflammatory properties, anabolic effects on skeletal muscles and the ability to suppress bone density loss leading to osteoporosis. Ursolic acid also exhibits anti-microbial features against numerous strains of bacteria, HIV and HCV viruses and Plasmodium protozoa causing malaria.

Anxiolytic-like effects of ursolic acid in mice

Ursolic acid is a pentacyclic triterpenoid that possesses several biological and neuropharmacological effects including antidepressant-like activity. Anxiety disorders represent common and disability psychiatric conditions that are often associated with depressive symptoms. This work investigated the anxiolytic-like effects of ursolic acid administration in different behavioral paradigms that evaluate anxiety in mice: open field test, elevated plus maze test, light/dark box test and marble burying test. To this end, mice were administered with ursolic acid (0.1, 1 and 10mg/kg, p.o.) or diazepam (2mg/kg, p.o.), positive control, and submitted to the behavioral tests. The results show that ursolic acid (10mg/kg) elicited an anxiolytic-like effect observed by the increased total time in the center and decreased number of rearings responses in the open field test and an increased percentage of entries and total time spent in the open arms of elevated plus maze, similarly to diazepam. No significant effects of ursolic acid were shown in the light/dark box and marble burying test. These data indicate that ursolic acid exhibits anxiolytic-like effects in the open field and elevated plus maze test, but not in the light/dark box and marble burying test, showing the relevance of testing several behavioral paradigms in the evaluation of anxiolytic-like actions. Of note, the results extend the understanding on the effects of ursolic acid in the central nervous system and suggest that it may be a novel approach for the management of anxiety-related disorders.