Antidepressant effects of total iridoids of Valeriana jatamansi via the intestinal flora-blood-brain barrier pathway

Health benefits of medicinal plant natural products via microbiota-mediated different gut axes

This review examines the multifaceted roles of medicinal plant natural products in influencing gut microbiota and their subsequent impact on various organ systems through established gut axes, including the gut-brain, gut-liver, gut-heart, gut-lung, and gut-kidney axes. Medicinal plant natural products have exhibited diverse pharmacological activities, including modulation of microbiota composition, enhancement of metabolic processes, and alleviation of inflammation and oxidative stress. Evidence suggests that these components can ameliorate conditions such as neurological disorders, metabolic syndrome, and chronic kidney disease by restoring microbial balance and improving gut barrier integrity. Furthermore, the review highlights the potential of medicinal plant natural products to foster beneficial microbial communities and improve gut health, which may lead to reduced disease severity and inflammation. By comprehensively analyzing current literature, this review provides a foundation for future research aim at exploring the therapeutic applications of medicinal plant natural products in disease prevention and treatment. The findings underscore the need for further studies to elucidate the underlying mechanisms of action and validate the clinical efficacy of medicinal plant natural products in managing chronic conditions through gut microbiota modulation.

Microbiota-gut-brain axis: Natural antidepressants molecular mechanism

BACKGROUND

Major depressive disorder (MDD) is a severe mental health condition characterized by persistent depression, impaired cognition, and reduced activity. Increasing evidence suggests that gut microbiota (GM) imbalance is closely linked to the emergence and advancement of MDD, highlighting the potential significance of regulating the "Microbiota-Gut-Brain" (MGB) axis to impact the development of MDD. Natural products (NPs), characterized by broad biological activities, low toxicity, and multi-target characteristics, offer unique advantages in antidepressant treatment by regulating MGB axis.

PURPOSE

This review was aimed to explore the intricate relationship between the GM and the brain, as well as host responses, and investigated the mechanisms underlying the MGB axis in MDD development. It also explored the pharmacological mechanisms by which NPs modulate MGB axis to exert antidepressant effects and addressed current research limitations. Additionally, it proposed new strategies for future preclinical and clinical applications in the MDD domain.

METHODS

To study the effects and mechanism by which NPs exert antidepressant effects through mediating the MGB axis, data were collected from Web of Science, PubMed, ScienceDirect from initial establishment to March 2024. NPs were classified and summarized by their mechanisms of action.

RESULTS

NPs, such as flavonoids,alkaloids,polysaccharides,saponins, terpenoids, can treat MDD by regulating the MGB axis. Its mechanism includes balancing GM, regulating metabolites and neurotransmitters such as SCAFs, 5-HT, BDNF, inhibiting neuroinflammation, improving neural plasticity, and increasing neurogenesis.

CONCLUSIONS

NPs display good antidepressant effects, and have potential value for clinical application in the prevention and treatment of MDD by regulating the MGB axis. However, in-depth study of the mechanisms by which antidepressant medications affect MGB axis will also require considerable effort in clinical and preclinical research, which is essential for the development of effective antidepressant treatments.

Research progress in the ethnopharmacology, phytochemistry, pharmacology, toxicology, and quality control of Valeriana jatamansi Jones

ETHNOPHARMACOLOGIC RELEVANCE

Valeriana jatamansi Jones, belongs to the Valerianaceae family, is widely used in traditional Chinese medicine (TCM) and Ayurveda, traditional Indian medicine (TIM). This traditional herb has been officially listed in the pharmacopoeia of sixteen countries. Its usage was first described in Diannan Bencao, also known as "Zhizhuxiang", is a famous folk medicine herb with a long history of medicinal usage in China, and it was used to treat indigestion, flu, and mental disorders in the Han, Achang, Bai, Blang, Dai, Jingpo, Naxi, and Wa ethnic groups. In recent years, V. jatamansi has attracted worldwide attention as an important medicinal due to its pharmacological activity especially in nervous and digestive systems, and multiple uses.

AIM OF THE STUDY

The current review aims to provide a comprehensive analysis of the botany, traditional uses, phytochemistry, pharmacology, toxicity, and quality control of V. jatamansi.

MATERIALS AND METHODS

The relevant information of V. jatamansi was obtained from several databases including Web of Science, PubMed, ACS Publications, Google Scholar, Baidu Scholar, CNKI, Ph.D. and MSc dissertations, using "Valeriana jatamansi Jones", "Valeriana jatamansi", and "" as keywords. After eliminating repetitive and low-quality reports, the remaining reports were analyzed and summarized to prepare this review. Plant information was retrieved by www.worldfloraonline.org and www.gbif.org using "Valeriana jatamansi Jones" as keyword.

RESULTS

V. jatamansi has been historically utilized as a traditional medicine to treat various diseases, including infectious, inflammatory, neurological, and gastrointestinal disorders. More than 400 compounds have been identified in V. jatamansi including iridoids, volatile oils, lignans, flavonoids, phenolic acids, phenylpropanoids, sesquiterpenes, sesquiterpene hydrocarbons, triterpenes as well as other compounds. The plant extracts and compounds showed various pharmacological activities such as antitumor, cytotoxic, antivirus, etc. In addition, V. jatamansi has found various applications in the agricultural, food, and cosmetics industry.

CONCLUSION

A review of literature shows V. jatamansi has pharmacological properties valuable in treating diseases, particularly for antianxiety and gastrointestinal disorders. Despite a wide spectrum of effects from specific compounds, research mainly focuses on in vitro and in vivo, with a lack of pharmacokinetics, clinical trials and underlying mechanisms. Consequently, it becomes important to embark on additional researchs to elucidate the pharmacokinetics, material basis and mechanisms of V. jatamansi, thereby realizing the aspiration of its comprehensive utilization and sustainable development.

Iridoids rich fraction from Valeriana jatamansi Jones promotes axonal regeneration and motor functional recovery after spinal cord injury through activation of the PI3K/Akt signaling pathway

Valeriana jatamansi Jones (VJJ), renowned for its extensive history in traditional Chinese medicine and ethnomedicine within China, is prevalently utilized to alleviate ailments such as epigastric distension and pain, gastrointestinal disturbances including food accumulation, diarrhea, and dysentery, as well as insomnia and other diseases. Moreover, the Iridoid-rich fraction derived from Valeriana jatamansi Jones (IRFV) has demonstrated efficacy in facilitating the recuperation of motor functions after spinal cord injury (SCI). This study is aimed to investigate the therapeutic effect of IRFV on SCI and its underlying mechanism. Initially, a rat model of SCI was developed to assess the impact of IRFV on axonal regeneration. Subsequently, employing the PC12 cell model of oxidative damage, the role and mechanism of IRFV in enhancing axonal regeneration were explored using the phosphoinositide-3-kinase (PI3K)/protein kinase B (Akt) signaling pathway inhibitor LY294002. Ultimately, the same inhibitor was administered to SCI rats to confirm the molecular mechanism through which IRFV promotes axonal regeneration by activating the PI3K/Akt signaling pathway. The results showed that IRFV significantly enhanced motor function recovery, reduced pathological injury, and facilitated axonal regeneration in SCI rats. In vitro experiments revealed that IRFV improved PC12 cell viability, augmented axonal regeneration, and activated the PI3K/Akt signaling pathway. Notably, the inhibition of this pathway negated the therapeutic benefits of IRFV in SCI rats. In conclusion, IRFV promote promotes axonal regeneration and recovery of motor function after SCI through activation of the PI3K/Akt signaling pathway.

Mechanism of Valeriana Jatamansi Jones for the treatment of spinal cord injury based on network pharmacology and molecular docking

Spinal cord injury (SCI) is characterized by high rates of disability and death. Valeriana jatamansi Jones (VJJ), a Chinese herbal medicine, has been identified to improve motor function recovery in rats with SCI. The study aimed to analyze the potential molecular mechanisms of action of VJJ in the treatment of SCI. The main ingredients of VJJ were obtained from the literature and the SwissADME platform was used to screen the active ingredients. The Swiss TargetPrediction platform was used to predict the targets of VJJ, and the targets of SCI were obtained from the GeneCards and OMIM databases. The intersecting genes were considered potential targets of VJJ in SCI. The protein-protein interaction network was constructed using the STRING database and the hub genes of VJJ for SCI treatment were screened according to their degree values. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed using the Metascape database. Cytoscape software was used to construct the "herb-ingredient-target-pathway" network. Preliminary validation was performed using molecular docking via Auto Dock Vina software. A total of 56 active ingredients of VJJ, mainly iridoids, were identified. There were 1493 GO items (P < .01) and 173 signaling pathways (P < .01) obtained from GO and Kyoto Encyclopedia of Genes and Genomes enrichment, including the phosphoinositide-3-kinase (PI3K)-protein kinase B (Akt) signaling pathway, hypoxia-inducible factor 1 signaling pathway, and tumor necrosis factor signaling pathway. Molecular docking revealed that 12 hub genes enriched in the PI3K/Akt signaling pathway had a high binding affinity for the active ingredient of VJJ. VJJ may exert its therapeutic effects on SCI through the iridoid fraction, acting on signal transducer and activator of transcription 3, CASP3, AKT1, tumor necrosis factor, mammalian target of rapamycin, interleukin 6, and other hub genes, which may be related to the PI3K/Akt signaling pathway.

The synergistic mechanism of action of Dajianzhong decoction in conjunction with ketamine in the treatment of depression

Depression is a multifactorial syndrome with a variety of underlying pathological mechanisms. While ketamine, an N-methyl-D-aspartate receptor (NMDAR) antagonist, exhibits a rapid antidepressant action in the central never system (CNS), the potential addiction and psychotomimetic adverse effects of ketamine limit its chronic use in clinical practice. Therefore, it is necessary to discover an additional agent that shows a synergistic antidepressant activity with ketamine to sustain its therapeutic action so as to reduce its use frequency in depression treatment. The present study indicated that Dajianzhong decoction (DJZT), an empirical herbal formula used for the clinical treatment of several inflammation-related intestinal disorders, sustains behavioral and synaptic action of ketamine in depressive mouse models. Additionally, ketamine was also demonstrated to exert a synergistic action with DJZT to alleviate the chronic unpredictable mild stress (CUMS)-induced abnormalities in gut barrier proteins and colonic histology, and subsequently to normalize the diversity and composition of gut microbiota. Furthermore, DJZT was shown to possess an anti-inflammatory activity to prevent activation of NF-κB from releasing proinflammatory cytokines, specifically through inhibiting Th17 cells/IL-17A pathway. Our results uncovered the mechanism of action of DJZT in conjunction with ketamine in depression treatment by which these agents target different pathological factors across biological systems and exert a synergistic activity through a bidirectional communication in the gut-brain axis, and also provided new insights into the systematic treatment of depression.

Gentiopicroside improves high-fat diet-induced NAFLD in association with modulation of host serum metabolome and gut microbiome in mice

Objective

The incidence of non-alcoholic fatty liver disease is increasing every year, and there is growing evidence that metabolites and intestinal bacteria play a causal role in NAFLD. Gentiopicroside, a major iridoids compound in gentian, has been reported to reduce hepatic lipid accumulation. However to date, no studies have confirmed whether the predominance of Gentiopicroside is related to metabolites and intestinal bacteria. Therefore, we sought to study whether the hypolipidemic effect of Gentiopicroside is related to metabolic function and intestinal flora regulation.

Methods

In the present study, C57BL/6J mice were fed a high-fat diet for 12 weeks, followed by a high-fat diet with or without Gentiopicroside for 8 weeks, respectively. The Gentiopicroside intervention reduced body weight gain, liver index, and decreased serum biochemical parameters such as alanine aminotransferase, aspartate aminotransferase, and triglycerides in high-fat fed mice. The effect of Gentiopicroside on non-alcoholic fatty liver disease was studied using serum untargeted metabolomics and 16S rDNA assay.

Results

Metabolomic analysis showed that the addition of Gentiopicroside significantly altered the levels of amino acids, unmetabolized Gentiopicroside after administration, and metabolites such as Cinnoline, Galabiosylceramide, and Tryptophyl-Tyrosine, which are involved in the pathways regulating bile secretion, tryptophan metabolism, and lipid metabolism. Analysis of intestinal bacteria showed that Gentiopicrosides altered the community composition structure of intestinal bacteria, characterized by an increase and a decrease in beneficial and harmful bacteria, respectively. In addition, correlation analysis showed that the effect of Gentiopicroside on metabolites was positively correlated with intestinal flora Bacteroides, Lactobacillus, Muribaculum, and Prevotellaceae_UCG_001. Finally, the combined analysis revealed that metabolites were associated with the regulation of Firmicutes and Actinobacteria and positively correlated with lipid levels.

Conclusion

These results suggest that Gentiopicroside may be a potential agent for the prevention of intestinal disorders and the alleviation of non-alcoholic fatty liver disease.

Interactions Between Antidepressants and Intestinal Microbiota

The microbiota-gut-brain axis has been shown to influence human health and diseases, including depression. The interactions between drugs and intestinal microbiota are complex and highly relevant to treat diseases. Studies have shown an interaction between antidepressants and intestinal microbiota. Antidepressants may alter the abundance and composition of intestinal microbiota, which are closely related to the treatment outcomes of depression. Intestinal microbiota can influence the metabolism of antidepressants to change their availability (e.g., tryptophan can be metabolized to kynurenine by intestinal microbiota) and regulate their absorption by affecting intestinal permeability. In addition, the permeability of the blood-brain barrier can be altered by intestinal microbiota, influencing antidepressants to reach the central nervous system. Bioaccumulation is also a type of drug-microbiota interaction, which means bacteria accumulate drugs without biotransformation. These findings imply that it is important to consider intestinal microbiota when evaluating antidepressant therapy regimens and that intestinal microbiota can be a potential target for depression treatment.

Therapeutic potential of plant iridoids in depression: a review

CONTEXT

Depression is a mental disorder characterized by low mood, reduced interest, impaired cognitive function, and vegetative symptoms such as sleep disturbances or poor appetite. Iridoids are the active constituents in several Chinese classical antidepressant formulae such as Yueju Pill, Zhi-Zi-Hou-Po Decoction, Zhi-Zi-Chi Decoction, and Baihe Dihuang Decoction. Parallel to their wide usages, iridoids are considered potential lead compounds for the treatment of neurological diseases.

OBJECTIVE

The review summarizes the therapeutic potential and molecular mechanisms of iridoids in the prevention or treatment of depression and contributes to identifying research gaps in iridoids as potential antidepressant medication.

METHODS

The following key phrases were sought in PubMed, Google Scholar, Web of Science, and China National Knowledge Internet (CNKI) without time limitation to search all relevant articles with in vivo or in vitro experimental studies as comprehensively as possible: ('iridoid' or 'seciridoid' or 'depression'). This review extracted the experimental data on the therapeutic potential and molecular mechanism of plant-derived iridoids for depression.

RESULTS

Plant iridoids (i.e., catalpol, geniposide, loganin), and secoiridoids (i.e., morroniside, gentiopicroside, oleuropein, swertiamarin), all showed significant improvement effects on depression.

DISCUSSION AND CONCLUSIONS

Iridoids exert antidepressant effects by elevating monoamine neurotransmitters, reducing pro-inflammatory factors, inhibiting hypothalamic-pituitary-adrenal (HPA) axis hyperactivity, increasing brain-derived neurotrophic factor (BDNF) and its receptors, and elevating intestinal microbial abundance. Further detailed studies on the pharmacokinetics, bioavailability, and key molecular targets of iridoids are also required in future research, ultimately to provide improvements to current antidepressant medications.