Antidepressant-like effects of Cortex Mori Radicis extract via bidirectional phosphorylation of glucocorticoid receptors in the hippocampus

pH-Sensitive In Situ Gel of Mirtazapine Invasomes for Rectal Drug Delivery: Protruded Bioavailability and Anti-Depressant Efficacy

The present research emphasizes fabrication alongside the assessment of an innovative nano-vesicular membranous system known as invasomes (NVMs) laden with Mirtazapine for rectal administration. This system could circumvent the confines of orally administered counterparts regarding dose schedules and bioavailability. Mirtazapine invasomes were tailored by amalgamating phospholipid, cineole, and ethanol through a thin-film hydration approach rooted in the Box-Behnken layout. Optimization of composition parameters used to fabricate desired NVMs' physicochemical attributes was undertaken using the Design-Expert® program. The optimal MRZ-NVMs were subsequently transformed to a pH-triggered in situ rectal gel followed by animal pharmacodynamic and pharmacokinetic investigations relative to rectal plain gel and oral suspension. The optimized NVMs revealed a diameter size of 201.3 nm, a z potential of -28.8 mV, an entrapment efficiency of 81.45%, a cumulative release within 12 h of 67.29%, and a cumulative daily permeated quantity of 468.68 µg/cm2. Compared to the oral suspension, pharmacokinetic studies revealed a 2.85- and 4.45-fold increase in calculated rectal bioavailability in circulation and brain, respectively. Pharmacodynamic and immunohistopathology evaluations exposed superior MRZ-NVMs attributed to the orally administered drug. Consequently, rectal MRZ-NVMs can potentially be regarded as a prospective nanoplatform with valuable pharmacokinetics and tolerability assets.

Intranasal Nanotransferosomal Gel for Quercetin Brain Targeting: II. Antidepressant Effect in an Experimental Animal Model

Depression is a serious mental disorder and the most prevalent cause of disability and suicide worldwide. Quercetin (QER) demonstrated antidepressant effects in rats exhibiting anxiety and depressive-like behaviors. In an attempt to improve QER's antidepressant activity, a QER-loaded transferosome (QER-TFS) thermosensitive gel for intranasal administration was formulated and optimized. The therapeutic effectiveness of the optimized formulation was assessed in a depressed rat model by conducting a behavioral analysis. Behavioral study criteria such as immobility, swimming, climbing, sucrose intake, number of crossed lines, rearing, active interaction, and latency to feed were all considerably enhanced by intranasal treatment with the QER-TFS in situ gel in contrast to other formulations. A nasal histopathological study indicated that the QER-TFS thermosensitive gel was safe for the nasal mucosa. An immunohistochemical analysis showed that the animals treated with the QER-TFS thermosensitive gel had the lowest levels of c-fos protein expression, and brain histopathological changes in the depressed rats were alleviated. According to pharmacodynamic, immunohistochemical, and histopathological experiments, the intranasal administration of the QER-TFS thermosensitive gel substantially alleviated depressive symptoms in rats. However, extensive preclinical investigations in higher animal models are needed to anticipate its effectiveness in humans.

Mifepristone's effects on depression- and anxiety-like behavior in rodents

Mifepristone is a non-selective progesterone (PR), glucocorticoid (GR), and androgen receptor (AR) antagonist with antidepressant and anxiolytic effects. The dose and duration of mifepristone administration vary in rodent preclinical studies to evaluate depression-like and anxiety-like behavior. This review summarizes the findings so far and attempts to reconcile some of the differences in the results. While a few studies assessed basal depression- and anxiety-like behavior, several studies have used mifepristone in conjunction with stress, corticosterone/dexamethasone (after adrenalectomy), or progesterone administration. The effect of mifepristone on depression-like behavior appears to depend not only on the dose and duration of administration but also on the intensity or type of stress. In addition, the anxiolytic effects may depend on the species and strain of the experimental animals. More reports assess antidepressant-like or anxiolytic-like effects following acute than chronic administration. These effects are dependent on the paradigms and the nature of stressors. Most mifepristone studies implicate the role of GRs, yet only two reports have confirmed its role using a genetic approach, whereas none implicate the role of PRs/ARs. There are several novel selective GR antagonists whose effects on depression- and anxiety-like behavior are yet to be studied. Future studies could aim to confirm the role of GRs and evaluate the contribution of PRs/ARs to the effects of mifepristone. Such studies will contribute to a better understanding of depression, anxiety, and other mood disorders and develop novel strategies, particularly for treatment-resistant conditions.

Regulatory effects and potential therapeutic implications of alarin in depression, and arguments on its receptor

Alarin is a pleiotropic peptide involved in a multitude of putative biological activities, notably, it has a regulatory effect on depression-like behaviors. Although further elucidating research is needed, animal-based cumulative evidence has shown the antidepressant-like effects of alarin. In light of its regulatory role in depression, alarin could be used as a promising antidepressant in future treatment for depression. Nevertheless, the available information is still insufficient and the therapeutic relevance of alarin in depression is still of concern. Moreover, a plethora of studies have reported that the actions of alarin, including antidepressant activities, are mediated by a separate yet unidentified receptor, highlighting the need for more extensive research. This review focuses on the current understanding of the regulatory effects and future therapeutic relevance of alarin on depression, and the arguments on its receptors.

Therapeutic effects of herbal formula Huangqisan on metabolic disorders via SREBF1, SCD1 and AMPK signaling pathway

OBJECTIVE

Metabolic syndrome is a complex medical condition that has become an alarming epidemic, but an effective therapy for this disease is still lacking. The use of the herbal formula Huangqisan (HQS) to treat diabetes is documented in the Chinese medical literature as early as 1117 A.D.; however, its therapeutic effects and underlying mechanisms remain elusive.

METHODS

To investigate the beneficial effects of HQS on metabolic disorders, high-fat diet-induced obesity (DIO), leptin receptor dysfunction (db/db) and low-density lipoprotein receptor-knockout (LDLR^-/-) mice were used. Obese mice were treated with either HQS or vehicle. Blood, liver tissue, white fat tissue and brown adipose tissue were harvested at the end of the treatment. Metabolic disease-related parameters were evaluated to test effects of HQS against diabetes, obesity and hyperlipidemia. Aortic arches from LDLR^-/- mice were analyzed to investigate the effects of HQS on atherosclerosis. RNA-sequence, quantitative real-time polymerase chain reaction and Western blot were performed to investigate the mechanisms of HQS against metabolic disorder.

RESULTS

HQS lowered body weight, fasting blood glucose and serum lipid levels and improved glucose tolerance and insulin sensitivity in DIO mice and db/db mice (P < 0.05). HQS also blocked atherosclerotic plaque formation in LDLR^-/- mice. HQS suppressed de novo lipid synthesis by reducing the expression of messenger RNA for sterol regulatory element-binding factor 1, stearyl coenzyme A desaturase 1 and fatty acid synthase, and enhancing adenosine 5'-monophosphate-activated protein kinase signaling in both in vivo and in vitro experiments, indicating potential mechanisms for HQS's activity against diabetes.

CONCLUSION

HQS is effective for reversing metabolic disorder and has the potential to be used as therapy for metabolic syndrome.

Kuwanon G protects HT22 cells from advanced glycation end product-induced damage

The incidence of diabetic encephalopathy is increasing as the population ages. Evidence suggests that formation and accumulation of advanced glycation end products (AGEs) plays a pivotal role in disease progression, but limited research has been carried out in this area. A previous study demonstrated that Kuwanon G (KWG) had significant anti-oxidative stress and anti-inflammatory properties. As AGEs are oxidative products and inflammation is involved in their generation it is hypothesized that KWG may have effects against AGE-induced neuronal damage. In the present study, mouse hippocampal neuronal cell line HT22 was used. KWG was shown to significantly inhibit AGE-induced cell apoptosis in comparison with a control treatment, as determined by both MTT and flow cytometry. Compared with the AGEs group, expression of pro-apoptotic protein Bax was reduced and expression of anti-apoptotic protein Bcl-2 was increased in the AGEs + KWG group. Both intracellular and extracellular levels of acetylcholine and choline acetyltransferase were significantly elevated after KWG administration in comparison with controls whilethe level of acetylcholinesterase decreased. These changes in protein expression were accompanied by increased levels of superoxide dismutase and glutathione peroxidase synthesis and reduced production of malondialdehyde and reactive oxygen species. Intracellular signaling pathway protein levels were determined by western blot and immunocytochemistry. KWG administration was found to prevent AGE-induced changes to the phosphorylation levels of Akt, IκB-α, glycogen synthase kinase 3 (GSK3)-α and β, p38 MAPK and NF-κB p65 suggesting a potential neuroprotective effect of KWG against AGE-induced damage was via the PI3K/Akt/GSK3αβ signaling pathway. The findings of the present study suggest that KWG may be a potential treatment for diabetic encephalopathy.

Effects of Mulberry on The Central Nervous System: A Literature Review

Background

Mulberry, including several species belonging to genus Morus, has been widely used as a traditional medicine for a long time. Extracts and active components of mulberry have many positive neurological and biological effects and can become potential candidates in the search for new drugs for neurological disorders.

Objectives

We aimed to systematically review the medical literature for evidence of mulberry effects on the central nervous system.

Methods

We conducted a systematic search in nine databases. We included all in vivo studies investigating the effect of mulberry on the central nervous system with no restrictions.

Results

We finally included 47 articles for quality synthesis. Our findings showed that mulberry and its components possessed an antioxidant effect, showed a reduction in the cerebral infarct volume after stroke. They also improved the cognitive function, learning process, and reduced memory impairment in many animal models. M. alba and its extracts ameliorated Parkinson's disease-like behaviors, limited the complications of diabetes mellitus on the central nervous system, possessed anti-convulsant, anti-depressive, and anxiolytic effects.

Conclusion

Mulberry species proved beneficial to many neurological functions in animal models. The active ingredients of each species, especially M. alba, should be deeper studied for screening potential candidates for future treatments.

Mori Cortex Radicis Attenuates High Fat Diet-Induced Cognitive Impairment via an IRS/Akt Signaling Pathway

Present study was conducted to investigate ameliorating effects of Mori Cortex radicis on cognitive impair and neuronal defects in HFD-induced (High Fat Diet-Induced) obese mice. To induce obesity, C57BL/6 mice were fed an HFD for 8 weeks, and then mice were fed the HFD plus Mori Cortex radicis extract (MCR) (100 or 200 mg/kg/day) for 6 weeks. Prior to sacrifice, body weights were measured, and Y-maze test and oral glucose tolerance test were performed. Serum lipid metabolic biomarkers (TG, LDL, and HDL/total cholesterol ratio) and antioxidant enzymes (glutathione, superoxide dismutase, and catalase), malondialdehyde (MDA), and acetylcholinesterase (AChE) levels were measured in brain tissues. The expressions of proteins related to insulin signaling (p-IRS, PI3K, p-Akt, and GLUT4) and neuronal protection (p-Tau, Bcl-2, and Bax) were examined. MCR suppressed weight gain, improved serum lipid metabolic biomarker and glucose tolerance, inhibited AChE levels and MDA production, and restored antioxidant enzyme levels in brain tissue. In addition, MCR induced neuronal protective effects by inhibiting p-Tau expression and increasing Bcl-2/Bax ratio, which was attributed to insulin-induced increases in the expressions p-IRS, PI3K, p-Akt, and GLUT4. These indicate MCR may reduce HFD-induced insulin dysfunction and neuronal damage and suggest MCR be considered a functional material for the prevention of T2DM-associated neuronal disease.

Antioxidant, Anti-inflammatory, and Antiproliferative Activity of Mori Cortex Radicis Extracts

Mori Cortex Radicis (MCR) is a well-known Korean and Chinese folk medicine with anti-obesity, anti-inflammatory, anti-asthmatic, and hypoglycemic activities. This study was aimed to evaluate the total phenolic and flavonoid contents, as well as intracellular antioxidant and anti-inflammatory effects of water and 70% (v/v) ethanol extracts of MCR. The antioxidant activities of MCR extracts were determined with diphenyl-2-picrylhydrazyl and 2,2′-azinobis[3-ethylbenzothiazoline-6-sulfonic] scavenging activity assays. The suppressive activities of MCR extracts on the production of nitric oxide (NO*) and the expression of cytokines, c-Fos, activated p38-Mitogen-activated protein kinase (MAPK), and Nuclear factor Kappa B (NF-κB) and splenocytes proliferation in lipopolysaccharide-treated macrophages were determined. Furthermore, this study demonstrated the effects of MCR on reactive oxygen species production in murine macrophages. Mori Cortex Radicis restored deoxyribonucleic acid damages at higher concentrations of the extracts and significantly suppressed free radicals and NO* production. In this study, MCR significantly restored inflammatory responses and intracellular antioxidant activities in murine macrophages (RAW 264.7), which anticipated that MCR could be used as a natural anti-inflammatory agent.

Proteomic profiling of the neurons in mice with depressive-like behavior induced by corticosterone and the regulation of berberine: pivotal sites of oxidative phosphorylation

Chronic corticosterone (CORT) stress is an anxiety and depression inducing factor that involves the dysfunction of glucocorticoid receptor (GR), brain-derived neurotrophic factor (BDNF), and neuronal plasticity. However, the regulation of proteomic profiles in neurons suffering CORT stress is remaining elusive. Thus, the proteomic profiles of mouse neuronal C17.2 stem cells were comprehensively investigated by TMT (tandem mass tag)-labeling quantitative proteomics. The quantitative proteomics conjugated gene ontology analysis revealed the inhibitory effect of CORT on the expression of mitochondrial oxidative phosphorylation-related proteins, which can be antagonized by berberine (BBR) treatment. In addition, animal studies showed that changes in mitochondria by CORT can affect neuropsychiatric activities and disturb the physiological functions of neurons via disordering mitochondrial oxidative phosphorylation. Thus, the mitochondrial energy metabolism can be considered as one of the major mechanism underlying CORT-mediated depression. Since CORT is important for depression after traumatic stress disorder, our study will shed light on the prevention and treatment of depression as well as posttraumatic stress disorder (PTSD).

Cortex Mori Radicis extract promotes neurite outgrowth in diabetic rats by activating PI3K/AKT signaling and inhibiting Ca2+ influx associated with the upregulation of transient receptor potential canonical channel 1

Cortex Mori Radicis extract (CMR) has various pharmacological properties, such as anti‑inflammatory, anti‑allergic and anti‑hyperglycemic effects. However, the effects and mechanisms of CMR in the neuroregeneration of diabetic peripheral neuropathy (DPN) are unclear. In the present study, the effects of CMR on neurite outgrowth of dorsal root ganglia (DRG) neurons in diabetic rats were investigated and its underlying mechanisms were explored. SD rats were subjected to a high‑fat diet with low‑dose streptozotocin to induce a Type II diabetes model with peripheral neuropathy. CMR was then applied for four weeks continuously with or without injection of small interfere (si)RNA targeting the transient receptor potential canonical channel 1 (TRPC1) via the tail vein. Blood glucose levels, the number of Nissl bodies, neurite outgrowth and growth cone turning in DRG neurons were evaluated. The expression of TRPC1 protein, Ca2+ influx and activation of the PI3K/AKT signaling pathway were also investigated. The results of the present study showed that CMR significantly lowered blood glucose levels, reversed the loss of Nissl bodies, induced neurite outgrowth and restored the response of the growth cone of DRG neurons in diabetic rats. CMR exerted neurite outgrowth‑promoting effects by increasing TRPC1 expression, reducing Ca2+ influx and enhancing AKT phosphorylation. siRNA targeting TRPC1 in the CMR group abrogated its anti‑diabetic and neuroregenerative effects, suggesting the involvement of TRPC1 in the biological effects of CMR on DPN.

Effects of Spray-Drying Temperatures and Ratios of Gum Arabic to Microcrystalline Cellulose on Antioxidant and Physical Properties of Mulberry Juice Powder

This study aimed to investigate the influences of inlet air temperatures (120 °C, 130 °C, 140 °C and 150 °C, 160 °C) and the ratios of gum Arabic to microcrystalline cellulose on the quality of mulberry juice powder produced by the spray drying process. Determination of moisture content, bulk density, solubility, total phenolic content (TPC), total anthocyanin content (TAC) and antioxidant capacity (AC) of the obtained powders was performed. The study on temperatures showed that all parameters studied were significantly affected by the shift in temperatures. The powder dried at 160 °C had the highest TPC (38.32 ± 0.36 mg GAE/g DW) and water solubility index (78.70 ± 0.75%); however, it had the lowest moisture content (3.90 ± 0.14%) when compared with the samples dried at other temperatures. Meanwhile, at 140 °C, powder samples with the highest TAC (4.690 ± 0.18 mg cyd-3-glu/g DW) and highest AC (648.09 ± 22.98 µmol TE/g DW), respectively, were obtained. Increasing microcrystalline cellulose and decreasing gum Arabic contents in the carrier mixtures showed significant decreases in moisture content, bulk density, solubility, TPC, TAC and AC.

Simultaneous Quantification of Two Flavonoids in Morus alba by High Performance Liquid Chromatography Coupled with Photodiode Array Detector

The root bark of Morus alba L. (Family: Moraceae) is an important medicinal herb in many countries and has long been used as a traditional medicine for the treatment of cough, fever, blood pressure reduction, and respiratory diseases. In the present study, the simultaneous determination of two flavonoids, kuwanon G and morusin, for quality control of M alba was conducted using high-performance liquid chromatography (HPLC) equipped with photodiode array (PDA) detector. The column used for separation of kuwanon G and morusin was a Gemini C18 analytical column maintained at 45°C. The mobile phase for efficient separation of two analytes was flowed 0.1% (v/v) aqueous formic acid-acetonitrile with gradient elution. The detection wavelength for quantification was set at 266 nm. The optimized method showed good linearity with coefficients of determination of 0.9998 within the tested concentration ranges. The limits of detection for the two flavonoids, kuwanon G and morusin, were 0.69 μg/mL and 0.35 μg/mL and the limits of quantification of kuwanon G and morusin, were 2.10 μ/mL and 1.07 μg/mL. The recoveries were 98.40–111.55% and the relative standard deviation (RSD) value was within 3.50%. The RSD values of intra- a g d interday precisions were 0.08–0.70% and 0.06-0.48%, respectively. The amounts of kuwanon G and morusin were 1.94-2.26 mg/g and 1.05–1.12 mg/g. The established HPLC-PDA method will help to improve the quality control of M. alba and related products.

Biochemical, hematological, and hormonal profile of rats orally administered methanol stem bark extract of Napoleona vogelii Hook and Planch (Lecythidaceae)

Napoleona vogelii is used in traditional medicine for the management of stomach aches, ulcer, and cancers. This study was conducted to investigate the subchronic toxicological effect of methanol stem bark extract of N. vogelii on biochemical, hematological, and hormonal profile of male and female rats. Forty rats of both sexes were randomly divided into four groups of 10 rats each and were administered 100, 200, and 400 mg/kg of the extract p.o. for 90 d. Ten milliliter per kilogram of distilled water p.o. was administered to control rats. On hematological assessment, mean corpuscular hemoglobin concentration was significantly (p < 0.01) increased at 400 mg/kg compared to control. Biochemical assessment showed a significant increase (p < 0.05) in levels of alanine aminotransferase and aspartate aminotransferase at 200 and 400 mg/kg, respectively, compared to control. Hormonal assessment of male rats revealed a significantly (p < 0.0001) reduced level of testosterone at all treatment doses compared to control while estradiol was significantly (p < 0.05) reduced at 100 mg/kg, but significantly (p < 0.0001) increased at 200 and 400 mg/kg respectively compared to control in female rats. Findings from this study demonstrate that N. vogelli is relatively safe on oral acute exposure but may possess the potential to cause hepatic dysfunction and infertility in male rats by perturbations of the hypothalamic-pituitary axis while conversely enhancing fertility in female rats on subchronic administration.

Role of ethanolic extract of Morus alba leaves on some biochemical and hematological alterations in irradiated male rats

PURPOSE

The present study aimed to evaluate the protective role of "Morus alba Linn (Family: Moraceae) commonly known as mulberry" leaves extract against hazardous effects of gamma rays in male rats.

MATERIALS AND METHODS

Thirty six male albino rats were divided into six groups (six rats/group); (1) control group received 1 ml distilled water, (2) low dose of extract (100 mg/kg) group treated daily with low oral dose of ethanolic extract of mulberry leaves (100 mg/kg body weight (b.wt.)) for 21 consecutive days, (3) high dose of extract (200 mg/kg) group treated daily with high oral dose of ethanolic extract of mulberry leaves (200 mg/kg b.wt.) for the same period, (4) irradiated group rats were subjected to whole body gamma irradiation at a shot dose of 7 Gy, (5) low dose of extract + irradiated group treated daily with low oral dose of ethanolic extract of mulberry leaves (100 mg/kg b.wt.) for 21 consecutive days then rats were exposed to gamma irradiation at a single dose of 7 Gy, (6) high dose of extract + irradiation group treated daily with high oral dose of ethanolic extract of mulberry leaves (200 mg/kg b.wt.) for 21 consecutive days then rats were exposed to gamma irradiation at a single dose of 7 Gy. Rats were sacrificed 1, 7, 15 days post gamma irradiation in all groups. Blood samples were taken at three intervals time in the six groups.

RESULTS

The results showed that whole body irradiation of rats induced significant decrease (p < 0.05) in red blood cells (RBCs), hemoglobin (Hb), hematocrit percentage (HCT%), platelet, white blood cells (WBCs), lymphocytes, neutrophils, serum glucose-6-phosphate dehydrogenase (G-6-PD) and insulin. The data also showed significant increase (p < 0.05) in serum total lipids, phospholipids, cholesterol, triglycerides, lactate dehydrogenase (LDH), creatine kinase (CK), and plasma glucose. Administration of mulberry leaves extract, either low or high concentrations to rats prior to irradiation caused significant improvement in the studied parameters.

CONCLUSIONS

Mulberry leaves extract prior to exposure to gamma irradiation has radio protector against hazardous effect of irradiation in male rats.

Mechanisms of Brain Glucocorticoid Resistance in Stress-Induced Psychopathologies

Exposure to stress activates the hypothalamic-pituitary-adrenal axis and leads to increased levels of glucocorticoid (GC) hormones. Prolonged elevation of GC levels causes neuronal dysfunction, decreases the density of synapses, and impairs neuronal plasticity. Decreased sensitivity to glucocorticoids (glucocorticoid resistance) that develops as a result of chronic stress is one of the characteristic features of stress-induced psychopathologies. In this article, we reviewed the published data on proposed molecular mechanisms that contribute to the development of glucocorticoid resistance in brain, including changes in the expression of the glucocorticoid receptor (GR) gene, biosynthesis of GR isoforms, and GR posttranslational modifications. We also present data on alterations in the expression of the FKBP5 gene encoding the main component of cell ultra-short negative feedback loop of GC signaling regulation. Recent discoveries on stress- and GR-induced changes in epigenetic modification patterns as well as normalizing action of antidepressants are discussed. GR and FKBP5 gene polymorphisms associated with stress-induced psychopathologies are described, and their role in glucocorticoid resistance is discussed.

Enhanced anti-immobility effects of Sanggenon G isolated from the root bark of Morus alba combined with the α2-antagonist yohimbine in the rat forced swim test

In this study, we aimed to determine whether Sanggenon G, an active compound isolated from the root bark of Morus alba, exhibited enhanced anti-immobility activity with the addition of the α2-antagonist yohimbine in rats subjected to forced swim test (FST)-induced depression. Fluoxetine (a selective serotonin reuptake inhibitor) treatment in rats reduced the immobility time, and pretreatment with yohimbine significantly enhanced the antidepressant-like behavior of fluoxetine at 5, 10 and 20 mg/kg. Similarly, Sanggenon G significantly decreased the immobility time, reducing immobility by a maximum of 43.9 % when treated at a dose of 20 mg/kg. Furthermore, pretreatment with yohimbine significantly enhanced the antidepressant-like behavior of Sanggenon G at 5 and 10 mg/kg. Our findings suggest that the antidepressant-like effect of Sanggenon G could be facilitated by concomitant use of the α2-antagonist. Further studies are needed to evaluate the potential of Sanggenon G as an alternative therapeutic approach for the treatment of depression.

Temporal variability of glucocorticoid receptor activity is functionally important for the therapeutic action of fluoxetine in the hippocampus

Previous studies have shown inconsistent results regarding the actions of antidepressants on glucocorticoid receptor (GR) signalling. To resolve these inconsistencies, we used a lentiviral-based reporter system to directly monitor rat hippocampal GR activity during stress adaptation. Temporal GR activation was induced significantly by acute stress, as demonstrated by an increase in the intra-individual variability of the acute stress group compared with the variability of the non-stress group. However, the increased intra-individual variability was dampened by exposure to chronic stress, which was partly restored by fluoxetine treatment without affecting glucocorticoid secretion. Immobility in the forced-swim test was negatively correlated with the intra-individual variability, but was not correlated with the quantitative GR activity during fluoxetine therapy; this highlights the temporal variability in the neurobiological links between GR signalling and the therapeutic action of fluoxetine. Furthermore, we demonstrated sequential phosphorylation between GR (S224) and (S232) following fluoxetine treatment, showing a molecular basis for hormone-independent nuclear translocation and transcriptional enhancement. Collectively, these results suggest a neurobiological mechanism by which fluoxetine treatment confers resilience to the chronic stress-mediated attenuation of hypothalamic-pituitary-adrenal axis activity.

Antidepressant-Like Effects of Sanggenon G, Isolated from the Root Bark of Morus alba, in Rats: Involvement of the Serotonergic System

The root bark of Morus alba is commonly used as an alternative medicine due to its numerous health benefits in humans. However, the antidepressant effects of various active components from M. alba have not been fully elucidated. In this study, we aimed to determine whether sanggenon G, an active compound isolated from the root bark of M. alba, exhibited antidepressant-like activity in rats subjected to forced swim test (FST)-induced depression. Acute treatment of rats with sanggenon G (30 mg/kg, intraperitoneally (i.p.)) significantly reduced immobility time and increased swimming time without any significant change in climbing. Rats treated with sanggenon G also exhibited a decrease in the limbic hypothalamic-pituitary-adrenal (HPA) axis response to the FST, as indicated by attenuation of the corticosterone response and decreased c-Fos immunoreactivity in the hypothalamic paraventricular nucleus (PVN). In addition, the antidepressant-like effects of sanggenon G were significantly inhibited by WAY100635 (1 mg/kg, i.p.; a selective 5-hydroxytryptamine1A (5-HT1A) receptor antagonist), but not SCH23390 (0.05 mg/kg, i.p.; a dopamine D1 receptor antagonist). Our findings suggested that the antidepressant-like effects of sanggenon G were mediated by an interaction with the serotonergic system. Further studies are needed to evaluate the potential of sanggenon G as an alternative therapeutic approach for the treatment of depression.

Novel antidepressant-like activity of caffeic Acid phenethyl ester is mediated by enhanced glucocorticoid receptor function in the hippocampus

Caffeic acid phenethyl ester (CAPE) is an active component of propolis that has a variety of potential pharmacological effects. Although we previously demonstrated that propolis has antidepressant-like activity, the effect of CAPE on this activity remains unknown. The present study assessed whether treatment with CAPE (5, 10, and 20 µmol/kg for 21 days) has an antidepressant-like effect in mice subjected to chronic unpredictable stress via tail suspension (TST) and forced swim (FST) tests. CAPE administration induced behaviors consistent with an antidepressant effect, evidenced by decreased immobility in the TST and FST independent of any effect on serum corticosterone secretion. Western blots, conducted subsequent to behavioral assessment, revealed that CAPE significantly decreased glucocorticoid receptor phosphorylation at S234 (pGR(S234)), resulting in an increased pGR(S220/S234) ratio. We also observed negative correlations between pGR(S220)/(S234) and p38 mitogen-activated protein kinase (p38MAPK) phosphorylation, which was decreased by CAPE treatment. These findings suggest that CAPE treatment exerts an antidepressant-like effect via downregulation of p38MAPK phosphorylation, thereby contributing to enhanced GR function.

Effect of Kuwanon G isolated from the root bark of Morus alba on ovalbumin-induced allergic response in a mouse model of asthma

The root bark of Morus alba L. (Mori Cortex Radicis; MCR) is traditionally used in Korean medicine for upper respiratory diseases. In this study, we investigated the antiasthmatic effect of kuwanon G isolated from MCR on ovalbumin (OVA)-induced allergic asthma in mice. Kuwanon G (1 and 10 mg/kg) was administered orally in mice once a day for 7 days during OVA airway challenge. We measured the levels of OVA-specific IgE and Th2 cytokines (IL-4, IL-5, and IL-13) in the sera or bronchoalveolar lavage (BAL) fluids and also counted the immune cells in BAL fluids. Histopathological changes in the lung tissues were analyzed. Kuwanon G significantly decreased the levels of OVA-specific IgE and IL-4, IL-5, and IL-13 in the sera and BAL fluids of asthma mice. Kuwanon G reduced the numbers of inflammatory cells in the BAL fluids of asthma mice. Furthermore, the pathological feature of lungs including infiltration of inflammatory cells, thickened epithelium of bronchioles, mucus, and collagen accumulation was inhibited by kuwanon G. These results indicate that kuwanon G prevents the pathological progression of allergic asthma through the inhibition of lung destruction by inflammation and immune stimulation.

Antidepressant-like effects of the ethyl acetate soluble fraction of the root bark of Morus alba on the immobility behavior of rats in the forced swim test

In this study, the antidepressant-like effects of Morus alba fractions in rats were investigated in the forced swim test (FST). Male Wistar rats (9-week-old) were administered orally the M. alba ethyl acetate (EtOAc 30 and 100 mg/kg) and M. alba n-butanol fractions (n-BuOH 30 and 100 mg/kg) every day for 7 consecutive days. On day 7, 1 h after the final administration of the fractions, the rats were exposed to the FST. M. alba EtOAc fraction at the dose of 100 mg/kg induced a decrease in immobility behavior (p < 0.01) with a concomitant increase in both climbing (p < 0.05) and swimming (p < 0.05) behaviors when compared with the control group, and M. alba EtOAc fraction at the dose of 100 mg/kg decreased the hypothalamic-pituitary-adrenal (HPA) axis response to the stress, as indicated by an attenuated corticosterone response and decreased c-fos immunoreactivity in the hippocampal and hypothalamic paraventricular nucleus (PVN) region. These findings demonstrated that M. alba EtOAc fraction have beneficial effects on depressive behaviors and restore both altered c-fos expression and HPA activity.

Alarin-induced antidepressant-like effects and their relationship with hypothalamus-pituitary-adrenal axis activity and brain derived neurotrophic factor levels in mice

Alarin is a newly identified member of the galanin family of peptides. Galanin has been shown to exert regulatory effects on depression. Similar to galanin in distribution, alarin is also expressed in the medial amygdala and hypothalamus, i.e., regions interrelated with depression. However, it remains a puzzle whether alarin is involved in depression. Accordingly, we established the depression-like mouse model using behavioral tests to ascertain the possible involvement of alarin, with fluoxetine as a positive control. With the positive antidepressant-like effects of alarin, we further examined its relationship to HPA axis activity and brain-derived neurotrophic factor (BDNF) levels in different brain areas in a chronic unpredictable mild stress (CUMS) paradigm. In the acute studies, alarin produced a dose-related reduction in the immobility duration in tail suspension test (TST) in mice. In the open-field test, intracerebroventricular (i.c.v.) injection of alarin (1.0 nmol) did not impair locomotion or motor coordination in the treated mice. In the CUMS paradigm, alarin administration (1.0 nmol, i.c.v.) significantly improved murine behaviors (FST and locomotor activity), which was associated with a decrease in corticotropin-releasing hormone (CRH) mRNA levels in the hypothalamus, as well as a decline in serum levels of CRH, adrenocorticotropic hormone (ACTH) and corticosterone (CORT), all of which are key hormones of the HPA axis. Furthermore, alarin upregulated BDNF mRNA levels in the prefrontal cortex and hippocampus. These findings suggest that alarin may potentiate the development of new antidepressants, which would be further secured with the identification of its receptor(s).

Novel antidepressant-like activity of propolis extract mediated by enhanced glucocorticoid receptor function in the hippocampus

Propolis is a natural product made by honeybees that has been widely used in folk medicine with a broad spectrum of biological activities. To investigate the antidepressant-like activity of propolis extract, CD-1 mice were administered an ethanol extract of propolis (50, 100, or 200 mg/kg, p.o.) prior to the behavioral test. The propolis extract-treated group showed a dose-dependent decrease in immobility time in the FST and tail suspension test without altering locomotor activity. Propolis extract decreased the limbic hypothalamic-pituitary-adrenal axis response to the FST as indicated by an attenuated corticosterone response and decreased in c-fos immunoreactive neurons in the hippocampal dentate gyrus. Western blot analysis revealed a reduction in hippocampal glucocorticoid receptor (GR) expression following the FST, which was reversed by propolis extract. Propolis extract also increased pGR(S220)/(S234) ratio by a differential phosphorylation in S220 and S234. FST-induced downregulation of cAMP-responsive element binding protein phosphorylation at S133 (pCREB) was restored by propolis extract, showing a strong and positive relationship between pCREB and pGR(S220)/(S234) ratio. These findings suggest that the propolis extract potentiates antidepressant-like activity by enhancing GR function which is one of the therapeutic mechanisms of antidepressant; thus, propolis extract may provide a novel therapy for depression.