Echinacoside exhibits antidepressant-like effects through AMPAR-Akt/ERK-mTOR pathway stimulation and BDNF expression in mice

Beneficial Effects of Echinacoside on Cognitive Impairment and Diabetes in Type 2 Diabetic db/db Mice

INTRODUCTION

Cognitive dysfunction is an important comorbidity of diabetes. Insulin resistance may play a critical role in diabetes-related cognitive impairment. Echinacoside (ECH), a natural phenylethanoid glycoside, is the active component of anti-diabetes prescriptions in traditional Chinese medicine. Its effect on modulating insulin resistance has been confirmed but modulating neurodegenerative disease remains unclear.

METHODS

Db/db mice, a spontaneous type 2 diabetes mode, were intragastrically administered ECH by 300 mg/kg or an equivalent volume of saline. Weight, blood glucose, and insulin resistance index were measured. Morris water maze test was performed to observe the compound effects on cognition. Hippocampal lesions were observed by histochemical analysis.

RESULTS

In db/db mice, ECH alleviated diabetes symptoms, memory loss, and hippocampal neuronal damage. Next, the expression of CD44 and phosphorylated tau was upregulated in diabetic mice. In addition, the insulin receptor substrate-1/phosphatidylinositol 3-kinase /protein kinase B signaling pathway was dysregulated in diabetic mice. All these dysregulations could be reversed by ECH.

DISCUSSION

This study provides theoretical support and experimental evidence for the future application of ECH in diabetic cognition dysfunction treatment, promoting the development of traditional medicines.

Echinacea: Bioactive Compounds and Agronomy

For centuries, medicinal plants have been used as sources of remedies and treatments for various disorders and diseases. Recently, there has been renewed interest in these plants due to their potential pharmaceutical properties, offering natural alternatives to synthetic drugs. Echinacea, among the world's most important medicinal plants, possesses immunological, antibacterial, antifungal, and antiviral properties. Nevertheless, there is a notable lack of thorough information regarding the echinacea species, underscoring the vital need for a comprehensive review paper to consolidate existing knowledge. The current review provides a thorough analysis of the existing knowledge on recent advances in understanding the physiology, secondary metabolites, agronomy, and ecology of echinacea plants, focusing on E. purpurea, E. angustifolia, and E. pallida. Pharmacologically advantageous effects of echinacea species on human health, particularly distinguished for its ability to safeguard the nervous system and combat cancer, are discussed. We also highlight challenges in echinacea research and provide insights into diverse approaches to boost the biosynthesis of secondary metabolites of interest in echinacea plants and optimize their large-scale farming. Various academic databases were employed to carry out an extensive literature review of publications from 2001 to 2024. The medicinal properties of echinacea plants are attributed to diverse classes of compounds, including caffeic acid derivatives (CADs), chicoric acid, echinacoside, chlorogenic acid, cynarine, phenolic and flavonoid compounds, polysaccharides, and alkylamides. Numerous critical issues have emerged, including the identification of active metabolites with limited bioavailability, the elucidation of specific molecular signaling pathways or targets linked to echinacoside effects, and the scarcity of robust clinical trials. This raises the overarching question of whether scientific inquiry can effectively contribute to harnessing the potential of natural compounds. A systematic review and analysis are essential to furnish insights and lay the groundwork for future research endeavors focused on the echinacea natural products.

Echinacoside stimulates myogenesis and ATP-dependent thermogenesis in the skeletal muscle via the activation of D1-like dopaminergic receptors

Recent studies have shown that some natural compounds from plants prevent obesity and related disorders, including the loss of skeletal muscle mass and strength. In this study, we investigated the effect of echinacoside (ECH), a caffeic acid glycoside from the phenylpropanoid class, on myogenesis and ATP-dependent thermogenesis in the skeletal muscle and its interaction with the dopaminergic receptors 1 and 5 (DRD1 and DRD5). We applied RT-PCR, immunoblot analysis, a staining method, and an assay kit to determine the effects of ECH on diverse target genes and proteins involved in skeletal muscle myogenesis and ATP-consuming futile processes. Our study demonstrated that ECH enhanced myogenic differentiation, glucose, and fatty acid uptake, as well as lipid catabolism, and induced ATP-dependent thermogenesis in vitro and in vivo. Moreover, ECH upregulated mitochondrial biogenesis proteins, mitochondrial oxidative phosphorylation (OXPHOS) complexes, and intracellular Ca2+ signaling as well as thermogenic proteins. These findings were further elucidated by mechanistic studies which showed that ECH mediates myogenesis via the DRD1/5 in C2C12 muscle cells. In addition, ECH stimulates α1-AR-mediated ATP-dependent thermogenesis via the DRD1/5/cAMP/SLN/SERCA1a pathway in C2C12 muscle cells. To the best of our knowledge, this is the first report that demonstrates the myogenic and thermogenic potential of ECH activity through the dopaminergic receptors. Understanding the novel functions of ECH in terms of its ability to prevent skeletal muscle loss and energy expenditure via ATP-consuming futile processes could help to develop potential alternative strategies to address muscle-related diseases, including combating obesity.

Echinacoside: A promising active natural products and pharmacological agents

Echinacoside, a natural phenylethanoid glycoside, was discovered and isolated from the garden plant Echinacea angustifolia DC., belonging to the Compositae family, approximately sixty years ago. Extensive investigations have revealed that it possesses a wide array of pharmacologically beneficial activities for human health, particularly notable for its neuroprotective and anticancer activity. Several crucial concerns surfaced, encompassing the recognition of active metabolites that exhibited inadequate bioavailability in their prototype form, the establishment of precise molecular signal pathways or targets associated with the aforementioned effects of echinacoside, and the scarcity of dependable clinical trials. Hence, the question remains unanswered as to whether scientific research can effectively utilize this natural compound. To support future studies on this natural product, it is imperative to provide a systematic overview and insights into potential future prospects. The current review provides a comprehensive analysis of the existing knowledge on echinacoside, encompassing its wide distribution, structural diversity and metabolism, diverse therapeutic applications, and improvement of echinacoside bioavailability for its potential utilization.

Echinacoside Induces UCP1- and ATP-Dependent Thermogenesis in Beige Adipocytes via the Activation of Dopaminergic Receptors

Echinacoside (ECH) is a naturally occurring phenylethanoid glycoside, isolated from Echinacea angustifolia, and this study aimed to analyze its effect on thermogenesis and its interaction with dopaminergic receptors 1 and 5 (DRD1 and DRD5) in 3T3-L1 white adipocytes and mice models. We employed RT-PCR, immunoblot, immunofluorescence, a staining method, and an assay kit to determine its impact. ECH showed a substantial increase in browning signals in vitro and a decrease in adipogenic signals in vivo. Additionally, analysis of the iWAT showed that the key genes involved in beiging, mitochondrial biogenesis, and ATP-dependent thermogenesis were upregulated while adipogenesis and lipogenesis genes were downregulated. OXPHOS complexes, Ca2+ signaling proteins as well as intracellular Ca2+ levels were also upregulated in 3T3-L1 adipocytes following ECH treatment. This was collectively explained by mechanistic studies which showed that ECH mediated the beiging process via the DRD1/5-cAMP-PKA and subsequent downstream molecules, whereas it co-mediated the α1-AR-signaling thermogenesis via the DRD1/5/SERCA2b/RyR2/CKmt pathway in 3T3-L1 adipocytes. Animal experiments revealed that there was a 12.28% reduction in body weight gain after the ECH treatment for six weeks. The effects of ECH treatment on adipose tissue can offer more insights into the treatment of obesity and metabolic syndrome.

Effects of Echinacoside on Ehrlich Carcinoma in Rats by Targeting Proliferation, Hypoxia and Inflammation

Background and objectives Ehrlich solid carcinoma (ESC) is a type of tumor originating from a spontaneous mammary adenocarcinoma in mice. It is highly aggressive and fast-growing and can create a solid undifferentiated mass when inserted under the skin. This makes it an ideal model for assessing cancer biology and tumor immunology. Echinacoside is a natural phenylethanoid glycoside with anti-inflammatory, anti-endoplasmic reticulum stress, anti-oxidative stress, and other beneficial properties. This study explored the potential anti-cancer benefits of echinacoside in rats with ESC. The study also analyzed its effects on tumor cell proliferation, differentiation, motility, and inflammation. Methods The study involved injecting rats with tumors in their left hind limb using an intramuscular injection of 2×106 cells. After 14 days, some rats were given a daily intraperitoneal dose of 30 mg/kg echinacoside for three weeks. Muscle samples were then analyzed under an electron microscope. In addition, gene expression and protein levels of various factors such as phosphoinositide 3-kinases (PI3K), mammalian target of rapamycin (mTOR), hypoxia-inducible factor (HIF)-1α, cyclin D1, cyclin-dependent kinase 2 (CDK2), tumor necrosis factor (TNF)-α, and nuclear factor (NF)κB were evaluated in another part of the muscle samples. Results After being treated with echinacoside, the ESC rats experienced a significant increase in their mean survival time from 27 days to 48 days. This treatment also resulted in a decrease in the volume and weight of the tumor. Upon examining the tumor tissue under an electron microscope, signs of damage such as pleomorphic cells, necrosis, nuclear fragmentation, membrane damage with cytoplasmic content spilling, and loss of cellular junction were observed. However, the treatment with echinacoside was effective in improving these effects. Furthermore, the expression of PI3K, mTOR, HIF-1α, cyclin D1, CDK2, TNF-α, and NFκB was significantly reduced due to the echinacoside treatment. Conclusions Our research found that echinacoside has antitumor properties that resulted in a substantial decrease in tumor size and weight, leading to an increase in the average survival time of rats and an improvement in muscle structure. Additionally, echinacoside was shown to ameliorate hypoxia by suppressing HIF-1α, reduce inflammation by decreasing NFκB and TNF-α, decrease proliferation by reducing PI3K, and block cyclin D1 and CDK2 to inhibit differentiation.

The inhibitory mechanism of echinacoside against Staphylococcus aureus Ser/Thr phosphatase Stp1 by virtual screening and molecular modeling

CONTEXT

Stp1 is a new potential target closely related to the pathogenicity of Staphylococcus aureus (S. aureus). In this study, effective Stp1 inhibitors were screened via virtual screening and enzyme activity experiments, and the inhibition mechanism was analyzed using molecular dynamics simulation.

METHODS

AutoDock Vina 4.0 software was used for virtual screening. The molecular structures of Stp1 and ligands were obtained from the RCSB Protein Data Bank and Zinc database, respectively. The molecular dynamics simulation used the Gromacs 4.5.5 software package with the Amberff99sb force field and TIP3P water model. AutoDock Tools was used to add polar hydrogen atoms to Stp1 and distribute part of the charge generated by Kollman's combined atoms. The binding free energies were calculated using the Amber 10 package.

RESULTS

The theoretical calculation results are consistent with the experimental results. We found that echinacoside (ECH) substantially inhibits the hydrolytic activity of Stp1. ECH competes with the substrate by binding to the active center of Stp1, resulting in a decrease in Stp1 activity. In addition, Met39, Gly41, Asp120, Asn162, and Ile163 were identified to play key roles in the binding of Stp1 to ECH. The benzene ring of ECH also plays an important role in complex binding. These findings provide a robust foundation for the development of innovative anti-infection drugs.

Saffron essential oil ameliorates CUMS-induced depression-like behavior in mice via the MAPK-CREB1-BDNF signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Saffron, the dried stigma of Crocus sativus L., has a long history of use in the treatment of depression in traditional Chinese medicine and Islamic medicine. The unique aroma of saffron, primarily derived from its volatile oil, has been widely used by folk to mitigate anxiety and depression via sniffing because the aroma of saffron has a pleasant and invigorating effect.

AIM OF THE STUDY

This study aimed to investigate the antidepressant effect and the underlying mechanism of saffron essential oil (SEO) in mice exposed to chronic unpredictable mild stress (CUMS).

MATERIALS AND METHODS

In this study, compounds of SEO were identified using gas chromatography-mass spectrometry analysis, while network pharmacology was used to predict potential active compounds, antidepressant targets, and related signaling pathways of SEO. The CUMS depression model was further used to explore the therapeutic effect and possible mechanism of SEO. During the modeling period, mice were regularly administered fluoxetine (3.6 mg/kg, i.g.) or diluted SEO (2%, 4%, and 6% SEO, inhalation). The antidepressant and neuroprotective effects of SEO were evaluated by behavior tests (the open field test, the sucrose preference test, the tail suspension test, and the forced swimming test), hematoxylin-eosin staining, and Nissl staining. The enzyme-linked immunosorbent assay kits were used to measure dopamine (DA), 5-serotonin (5-HT), brain-derived neurotrophic factor (BDNF), and γ-aminobutyric acid (GABA) levels in serum. The relative abundance of Raf1, MEK1, P-ERK1/2/ERK1/2, P-CREB1/CREB1, BDNF, and P-Trk B/Trk B in the hippocampus was determined using western blot (WB).

RESULTS

According to the network pharmacology analysis, seven active SEO compounds mediated 113 targets related to depression treatment, most of which were enriched in the 5-HT synapse, calcium signaling pathway, and cAMP signaling pathway. In vivo experiments indicated that fluoxetine and SEO improved depression-like behaviors in depressed mice. The levels of 5-HT, DA, BDNF, and GABA in serum increased significantly. Histopathological examinations revealed that fluoxetine and SEO ameliorated neuronal damage in the hippocampus. WB analysis showed that the relative expressions of Raf1, MEK1, P-ERK1/2/ERK1/2, P-CREB1/CREB1, BDNF, and P-Trk B/Trk B were significantly higher in the fluoxetine and SEO groups than in the CUMS group.

CONCLUSION

Overall, these findings suggest that SEO significantly alleviates the depressive symptoms in CUMS exposed mice and partially restores hippocampal neuronal damage. Meanwhile, the best efficacy was observed in 4% SEO. Furthermore, the antidepressant mechanism of SEO is primarily dependent on the regulation of the MAPK-CREB1-BDNF signaling pathway.

ERK1/2-dependent BDNF synthesis and signaling is required for the antidepressant effect of microglia stimulation

Depressed mice have lower numbers of microglia in the dentate gyrus (DG). Reversal of this decline by a single low dose of lipopolysaccharide (LPS) may have antidepressant effects, but there is little information on the molecular mechanisms underlying this effect. It is known that impairment of brain-derived neurotrophic factor (BDNF) signaling is involved in the development of depression. Here, we used a combination of neutralizing antibodies, mutant mice, and pharmacological approaches to test the role of BDNF-tyrosine kinase receptor B (TrkB) signaling in the DG in the effect of microglial stimulation. Our results suggest that inhibition of BDNF signaling by infusion of an anti-BDNF antibody, the BDNF receptor antagonist K252a, or knock-in of the mutant BDNF Val68Met allele abolished the antidepressant effect of LPS in chronically stressed mice. Increased BDNF synthesis in DG, mediated by extracellular signal-regulated kinase1/2 (ERK1/2) signaling but not protein kinase B (Akt)-mammalian target of rapamycin (mTOR) signaling, was essential for the antidepressant effect of microglial stimulation. These results suggest that increased BDNF synthesis through activation of ERK1/2 caused by a single LPS injection and subsequent TrkB signaling are required for the antidepressant effect of hippocampal microglial stimulation.

Echinacoside inhibited cardiomyocyte pyroptosis and improved heart function of HF rats induced by isoproterenol via suppressing NADPH/ROS/ER stress

Prevalence of heart failure (HF) continues to rise over time and is a global difficult problem; new drug targets are urgently needed. In recent years, pyroptosis is confirmed to promote cardiac remodelling and HF. Echinacoside (ECH) is a natural phenylethanoid glycoside and is the major active component of traditional Chinese medicine Cistanches Herba, which is reported to possess powerful anti‐oxidation and anti‐inflammatory effects. In addition, we previously reported that ECH reversed cardiac remodelling and improved heart function, but the effect of ECH on pyroptosis has not been studied. So, we investigated the effects of ECH on cardiomyocyte pyroptosis and the underlying mechanisms. In vivo, we established HF rat models induced by isoproterenol (ISO) and pre‐treated with ECH. Indexes of heart function, pyroptotic marker proteins, ROS levels, and the expressions of NOX2, NOX4 and ER stress were measured. In vitro, primary cardiomyocytes of neonatal rats were treated with ISO and ECH; ASC speckles and caspase‐1 mediated pyroptosis in cardiomyocytes were detected. Hoechst/PI staining was also used to evaluate pyroptosis. ROS levels, pyroptotic marker proteins, NOX2, NOX4 and ER stress levels were all tested. In vivo, we found that ECH effectively inhibited pyroptosis, down‐regulated NOX2 and NOX4, decreased ROS levels, suppressed ER stress and improved heart function. In vitro, ECH reduced cardiomyocyte pyroptosis and suppressed NADPH/ROS/ER stress. We concluded that ECH inhibited cardiomyocyte pyroptosis and improved heart function via suppressing NADPH/ROS/ER stress.

Integrated analysis of phytochemical composition, pharmacokinetics, and network pharmacology to probe distinctions between the stems of Cistanche deserticola and C. tubulosa based on antidepressant activity

Cistanches Herba (CH), as a nutritional and functional supplement used in food and health care products for centuries, consists of the stems of Cistanche deserticola and C. tubulosa. Our previous studies confirmed that the stems of C. tubulosa exerted advantageous antidepressant effect. However, whether the difference in the phytochemical compositions between the stems of C. deserticola and C. tubulosa would lead to diverse bioavailability and accompanying antidepressant effects remain unclear, as well as their specific bioactive compounds and underlying mechanism. In this study, a series of comparative studies showed that the antidepressant activity of C. tubulosa extract (CTE) was stronger than that of the C. deserticola extract (CDE), which was accompanied with the discovery of 10 differential markers from 52 identified compounds between CTE and CDE, and different pharmacokinetic behaviors of 9 prototype and 4 metabolites belonging to the glycosides between the CTE-treated and CDE-treated group in normal and depressive rats were simultaneously found by a validated UPLC-QTRAP-MS/MS method. Subsequently, network pharmacology prediction, in vitro and in vivo experiment verification from these differential markers further revealed that 7 compounds were confirmed to contribute to the antidepressant action of CH by inhibiting neuronal apoptosis mediated by mitochondrial function and activation of the AKT/GSK3β signaling pathway, synchronously indicating most of those, with higher bioavailability in vivo after CTE administration, that were responsible for the stronger antidepressant effect of CTE over CDE. Hence, the integrated analysis of phytochemical composition, pharmacokinetics, and network pharmacology provide new insights into the applications of CH from different botanical origins against depression.

Echinacoside Inhibits Osteoclast Function by Down-Regulating PI3K/Akt/C-Fos to Alleviate Osteolysis Caused by Periprosthetic Joint Infection

Infected osteolysis as a common secondary osteoporosis is associated with excessive osteoclastogenesis and bone resorption. The inhibition of osteoclastogenesis and bone resorption have been demonstrated an effective approach in the treatment of osteolytic diseases. Echinacoside (ECH) is a natural phenylethanoid glycoside with multiple biological functions, including anti-inflammatory, antioxidant, and osteoblast differentiation promotion. However, the effects of ECH on osteoclast differentiation and bone resorption function remain unknown. In vitro, we investigated the effects of ECH on osteoclast differentiation and bone resorption induced by RANKL and its potential mechanisms. In vivo, we established a periprosthetic joint infection (PJI) rat model and demonstrated the changes of infected osteolysis and osteoclasts activities in surgical sites. ECH (20 mg/kg) was injected intraperitoneally after debridement for 4 weeks. Radiological evaluation and bone histomorphometric analysis was performed to assess the efficacy of ECH. The results showed that ECH inhibited osteoclast differentiation, F-actin belts formation, bone resorption function and osteoclast-specific gene expression by preventing NFATc1 translocation, down-regulating its expression and affecting the PI3K/Akt/c-Fos pathway in vitro. ECH also alleviated in vivo PJI-induced osteolysis and maintained bone mass by inhibiting osteoclast activity. Our study indicated that ECH attenuated RANKL-induced osteoclastogenesis and PJI-induced bone loss and was shown as a potentially effective therapeutic agent for osteoclast-related bone diseases.

Persimmon leaf extract alleviates chronic social defeat stress-induced depressive-like behaviors by preventing dendritic spine loss via inhibition of serotonin reuptake in mice

Background

Fresh or dried Persimmon leaves (Diospyros kaki Thunb.) exhibit preventive effects on cardiovascular and cerebrovascular diseases. However, their antidepressant effects and underlying mechanisms are unclear. Thus, we investigated mechanisms responsible for Persimmon leaf extract (PLE) activity on chronic social defeat stress (CSDS)-induced depressive-like behaviors in mice.

Methods

CSDS was used as a mouse model of depression. We performed the sucrose preference test (SPT), forced swim test (FST), and tail suspension test (TST) to identify depressive-like behavior. Spine density and dendritic morphology were assessed using Golgi staining. Neurochemicals were quantified by microdialysis, doublecortin by immunofluorescence, and cAMP using an ELISA kit. Finally, the levels of cortical proteins of phosphorylated cAMP-response element binding protein (CREB), brain-derived neurotrophic factor (BDNF), postsynaptic density synapsin-1 and protein 95 (PSD95) were quantified by western blot. 16S rRNA gene sequencing was used to detect fecal microbiota.

Results

Treatment of CSDS-subjected mice with PLE (30.0–60.0 mg/kg, i.g.) enhanced sucrose preference, decreased immobility times in the TST and FST but did not affect locomotor activity. Furthermore, persistent social defeat stress decreased dendritic spine density and dendritic length in the brain, as well as decreased PSD95 and synapsin-1 expression. PLE, interestingly, inhibited dendritic spine loss and increased synaptic protein levels. PLE also increased brain levels of 5-HT, cAMP, phosphorylated (p)-CREB, BDNF, PSD95, and synapsin-1 in mice subjected to CSDS. Furthermore, PLE increased their doublecortin-positive cell count in the hippocampal dentate gyrus. CSDS mice represented a distinct fecal microbiota cluster which differed compared with normal C57BL/6J mice, and the phenotype was rescued by PLE.

Conclusions

PLE alleviated CSDS-induced depressive behaviors and spinal damage by suppressing serotonin reuptake and activating the cAMP/CREB/BDNF signaling pathway. Simultaneously, PLE influenced the composition of the fecal microbiota in CSDS-subjected mice.

Supplementary information

The online version contains supplementary material available at 10.1186/s13020-022-00609-4.