Neuroplasticity: A Key Player in the Antidepressant Action of Chinese Herbal Medicine.

Traditional Chinese medicine (TCM) is a systematic medicine. It provides alternative strategies for the treatment of depression with its clinical experience, comprehensive diagnosis, and treatment theory. Chinese herbal medicine (CHM) is the major form of TCM prescription, and numerous CHMs have been demonstrated to possess remarkable antidepressant-like properties. A diversity of mechanisms have been implicated in CHM-associated antidepressant property. This paper reviewed the neuroplastic mechanisms underlying the antidepressant actions of CHM, finding that CHM repairs neuroplasticity by improving neurogenesis, neurotrophic factors, synaptic spine morphology, cell signaling, glutamatergic system, monoamine neurotransmitters, and neural apoptosis. CHM thereby exerts an antidepressant effect, attempting to offer a better understanding of the mechanisms implicated in TCM-related antidepressant-like efficacy and laying a foundation for the scientific evaluation and development of TCM in treating depression.

Iridoids from Gardeniae fructus ameliorates depression by enhancing synaptic plasticity via AMPA receptor-mTOR signaling.

ETHNOPHARMACOLOGICAL RELEVANCE: Gardeniae fructus is a traditional Chinese herb which exerts antidepressant effect. However, its effective constituent and potential mechanism are still unknown. AIM OF THE STUDY: To examine whether iridoids, a type of monoterpenoids from Gardeniae fructus (IGF), exerts antidepressant effect by enhancing synaptic plasticity via AMPA receptor-mTOR signaling. MATERIALS AND METHODS: The antidepressant effect of IGF (15 mg/kg; 30 mg/kg; 45 mg/kg) was investigated in spatial restraint stress (SRS)-induced mice. The expression levels of AMPA receptor-mTOR signaling and synaptic proteins were measured by Western blot, dendritic spine density was observed in Golgi staining. AMPA receptor (AMPAR) inhibitor NBQX and mTOR inhibitor Rapamycin were employed to determine the roles of AMPAR and mTOR signaling in IGF-induced antidepressant effects. RESULTS: After IGF administration, the expression of the AMPA glutamate receptor Glutamate Receptor 1 (GluA1) was inhibited in SRS mice. We also observed a trend toward the up-regulation of the mammalian target of Rapamycin (mTOR) protein kinase, p70 ribosomal protein S6K (P70S6K) and eukaryotic translation initiation factor 4E-binding protein 1 (4EBP1). The protein levels of Synapsin-1 and PSD-95 were decreased after SRS challenge, along with declined dendritic spine density, which were all reversed with IGF treatment. Furthermore, the treatment efficacy of IGF were blocked with AMPA receptor inhibitor NBQX or mTOR inhibitor Rapamycin. CONCLUSION: IGF exerted antidepressive-like effects by stimulating AMPAR-mTOR signaling regulated synaptic plasticity enhancement. This work provided an important basis for developing IGF and Gardeniae fructus as potential anti-depressants.

Effect of Wenshen-Yanggan Decoction on Movement Disorder and Substantia Nigra Dopaminergic Neurons in Mice with Chronic Parkinson's Disease.

This study aimed to explore the protective effects of Wenshen-Yanggan decoction on dopaminergic (DA) neuron injury in a rotenone-induced mouse model with chronic Parkinson's disease (PD) and explore its mechanism of action. Ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used to measure the content of six main components in the Wenshen-Yanggan decoction. The chronic PD mouse model was established by treating 10-month-old healthy wild C57BL/6 male mice with rotenone 30 mg/kg/day for 28 days in succession. The pole test and rotarod test were applied to detect the rescue effect of Wenshen-Yanggan decoction in high, medium, and low dosages, respectively, on PD-like behaviors in mice with chronic PD. The protective effect of Wenshen-Yanggan decoction on the mesencephalic nigrostriatal DA neuron injury was determined employing tyrosine hydroxylase (TH) immunofluorescence staining. Enzyme-linked immunosorbent assay (ELISA) was adopted to measure the inflammatory cytokines in serum, including TNF-α (tumor necrosis factor-alpha), IFN-γ (interferon gamma), NF-κB (nuclear factor kappa-B), and IL-1ß (interleukin-1 beta). Western blotting was performed to quantify the expression of phosphorylated c-Jun N-terminal kinase (p-JNK), cleaved caspase-3, B-cell lymphoma-2 (Bcl-2), and NF-κB in the brain. Our results showed that the Wenshen-Yanggan decoction in high, medium, and low dosages reduced the turning time of mice (P < 0.01, P < 0.01, and P < 0.05). The high and medium dosages shortened the total climbing time of PD mice in the pole test (P < 0.01 and P < 0.05). Meanwhile, the high, medium, and low dosages increased the rod-standing time of PD mice in the rotarod test (P < 0.01, P < 0.05, and P < 0.05). Besides, the decoction reversed the decrease in TH-positive neurons induced by rotenone, upregulated TH protein expression, and downregulated the α-syn expression in the PD model. Moreover, the decoction in high dosage significantly inhibited the expression of p-JNK, cleaved caspase-3, and NF-κB in the midbrain of PD mice (P < 0.05, P < 0.05, and P < 0.01), upregulated the expression of Bcl-2 (P < 0.05), and decreased the content of TNF-α, IFN-γ, NF-κB, and IL-1ß in the serum (P < 0.001, P < 0.001, P < 0.001, and P < 0.001). Taken together, the Wenshen-Yanggan decoction could protect mice from rotenone-induced chronic PD, which might be related to the reduction of the DA neuron apoptosis via suppressing the inflammatory reaction and the neuronal apoptosis pathway.

Involvement of mTOR-related signaling in antidepressant effects of Sophoraflavanone G on chronically stressed mice.

SophoraflavanoneG (SG), an important prenylated flavonoid isolated from Sophoraalopecuroides.L, is effective for many illnesses. The present study was designed to investigate whether the compound could reverse depressive-like symptoms and investigate its possible mechanisms. Chronic Unpredictable Mild Stress (CUMS) mice were treated with fluoxetine and SG. The immobility time in forced swimming test (FST) and tail suspension test (TST) were recorded. The levels of pro-inflammatory cytokines and neurotransmitters in the hippocampus were evaluated. Furthermore, the protein expressions of PI3K, AKT, mTOR, p70S6K, BDNF, and Trkb in hippocampus were detected. Rapamycin, the selective mTOR inhibitor, was used to estimate the potential mechanism. As a result, after 7 days of SG treatment, the immobility time in FST and TST was declined obviously. The levels of IL-6, IL-1ß, and TNF-α in the hippocampus were significantly reduced, and the quantity of 5-HT and NE was raised considerably in SG-treated group compared with the CUMS-exposed group. Additionally, SG could up-regulate the expressions of PI3K, AKT, mTOR, 70S6K, BDNF, and Trkb. The blockade of mammalian target of rapamycin signaling blunted the antidepressant effect and reversed the up-regulation of BDNF expression caused by SG. These findings suggested that SG treatment alleviated depressive-like symptoms via mTOR-mediated BDNF/Trkb signaling.

Anti-depressant effects of oil from fructus gardeniae via PKA-CREB-BDNF signaling.

The dried ripe fruit of Gardenia jasminoides Ellis was usually applied as an herb medicine in Traditional Chinese Medicine. It was suggested that the Gardenia jasminoides oil extract (oil from Fructus Gardeniae [OFG]) might serve as a potential treatment for depression, whereas its pathogenesis still remained not fully understood. The present research was conducted to evaluate the anti-depressive effect of OFG in mice and explore its potential mechanism. The OFG and ketamine (KET) were intragastrically and intraperitoneally treated, respectively. Thereafter, the animals were subjected to the behavior tests. The expressions of protein kinase A (PKA), brain derived neurotrophic factor (BDNF), cAMP response element-binding protein (CREB) in hippocampus were detected by Western blot. The selective PKA inhibitor H-89 was also applied to confirm the mechanism. As a result, OFG and KET treatment improved the behavior performance. Furthermore, the administrations of OFG effectively enhanced the expressions of PKA, p-CREB, and BDNF. With the application of selective PKA inhibitor H-89, the ameliorated effects caused by OFG were blocked, but not by KET. In conclusion, the presented work indicated that OFG-exerted protective effect on depression through PKA-CREB-BDNF signaling.

Two standardized fractions of Gardenia jasminoides Ellis with rapid antidepressant effects are differentially associated with BDNF up-regulation in the hippocampus.

ETHNOPHARMACOLOGICAL RELEVANCE: Gardenia jasminoides Ellis (GJ) is one of the five constituents of Yueju pill, a Traditional Chinese Medicine for treatment of syndromes associated with mood disorders. Recently, preclinical and clinical studies suggest that Yueju pill confers rapid antidepressant effects. GJ is identified as the constituent primary for Yueju pill's rapid antidepressant effects. GJ's antidepressant action is temporally associated with up-regulated expression of brain-derived neurotrophic factor (BDNF) in the hippocampus. The present study aimed to identify chemical fractions responsible for the rapid antidepressant efficacy of GJ and its association with BDNF signaling. MATERIALS AND METHODS: Four fractions of GJ were extracted using standardized procedure. The four fractions were screened for rapid antidepressant potential, using the behavioral paradigm of forced swimming test (FST) and tail suspension test (TST) assessed at 24h post a single administration. A single dose of the putatively effective fractions was further tested in mice exposed to chronic mild stress (CMS), followed with a comprehensive behavioral testing including TST, FST, sucrose preference test (SPT), and novelty suppressed-feeding (NSF). To test the association of BDNF signaling with rapid antidepressant effects of effective factions, the expressions of BDNF and its receptor tropomyosin receptor kinase B (TrkB) in the hippocampus were assessed at different times post a single administration of effective fractions. RESULTS: Both petroleum ether (GJ-PE) and n-butyl alcohol fraction (GJ-BO) fractions of GJ displayed rapid antidepressant potential in the FST. In the TST, the antidepressant effects of GJ-PE lasted for a longer time than GJ-BO. Acute administration of either GJ-PE or GJ-BO significantly reversed the behavioral deficits in the tests of TST, FST, SPT and NSF in chronically stressed mice, confirming both fractions conferred rapid antidepressant efficacy. Interestingly, GJ-PE, but not GJ-BO, increased the expression of BDNF and TrkB in the hippocampus post a single administration. CONCLUSION: Two standardized fractions GJ-PE and GJ-BO exhibited comparable rapid antidepressant-like effects on the CMS mice. However, only the effects of GJ-PE was associated with BDNF signaling.

A role of Yueju in fast-onset antidepressant action on major depressive disorder and serum BDNF expression: a randomly double-blind, fluoxetine-adjunct, placebo-controlled, pilot clinical study.

INTRODUCTION: Conventional antidepressants, including fluoxetine, have a major disadvantage in delayed onset of efficacy. Yueju, an herbal medicine used to treat mood disorders was recently found to exhibit rapid antidepressant effects. The present study was conducted to evaluate the role of Yueju in rapidly acting on major depressive disorder (MDD). METHODS: Participants were MDD patients with scores of 24-item Hamilton Depression Rating Scale (HDRS-24) ≥20 and without history of antidepressant use. They randomly received daily oral doses of Yueju (23 g/day) plus fluoxetine (20 mg/day) (experimental group) or placebo plus fluoxetine (control group) for 7 days. HDRS-24 was used as the primary outcome measurement at baseline, and on days 1, 3, 5, and 7. Concentrations of serum brain-derived neurotrophic factor (BDNF) were assessed at baseline and on days 1 and 7. RESULTS: In all, 18 participants met the criteria for data analysis. Compared to baseline level, only experimental group showed significant decrease of HDRS-24 score from day 3 to day 7 (P<0.05). Experimental group also showed significant improvement compared with control group from day 3 to day 7 (P<0.05). No correlation between treatment outcomes with serum BDNF levels was observed. However, experimental group showed significant correlation for serum BDNF level on day 1 with day 7 (r=0.721, P=0.028), whereas the control group did not. CONCLUSION: Yueju likely contributes to fast-onset antidepressant effects on MDD. Further investigation is necessary to firmly establish the ancient formula as a safe, efficacious, and rapidly acting alternative medicine for MDD treatment.

Involvement of normalized NMDA receptor and mTOR-related signaling in rapid antidepressant effects of Yueju and ketamine on chronically stressed mice.

Yueju, a Traditional Chinese Medicine formula, exhibited fast-onset antidepressant responses similar to ketamine. This study focused on assessing the rapid and persistent antidepressant efficacy of Yueju and ketamine in chronically stressed mice and its association with alternations in prefrontal N-methyl-D-aspartate (NMDA) receptor and mammalian target of rapamycin (mTOR)-related activity. Chronic mild stress (CMS) led to deficits in sucrose preference test (SPT), forced swim test, tail suspension test, and novelty-suppressed feeding test, which were improved differently by acute Yueju or ketamine administration. The improvement in SPT started as soon as 2 hours post Yueju and ketamine but lasted for 6 days only by Yueju. Body weight was regained by Yueju more than ketamine at post-drug administration day (PAD) 6. CMS decreased phosphorylation of the mTOR effectors 4E-BP1 and p70S6K, their upstream regulators ERK and Akt, and downstream targets including synaptic protein GluR1. Yueju or ketamine reversed these changes at PAD 2, but only Yueju reversed phosphor-Akt at PAD 6. CMS selectively and lastingly increased NMDA receptor subunit NR1 expression, which was reversed by ketamine or Yueju at PAD 2 but only by Yueju at PAD 6. These findings suggest that NR1 and Akt/mTOR signaling are important therapeutic targets for depression.

Optimization of supercritical fluid extraction of oil from the fruit of Gardenia jasminoides and its antidepressant activity.

A response surface methodology was applied to optimize the variables affecting the supercritical fluid carbon dioxide extraction of oil from the fruit of Gardenia jasminoides using the Box-Behnken design. The optimum extraction parameters were an extraction temperature of 49.94 °C, an extraction pressure of 29.89 MPa and an extraction time of 93.82 min. Through a GC/MS analysis, we revealed 16 major components of the oil extract, which showed potent antidepressant effects in both of two behavior despair models in mice: tail suspension test and forced swimming test. Our results suggest that the oil extract of Gardenia jasminoides prepared using the supercritical fluid carbon dioxide extraction may contain effective constituents to be used for depression therapy.