Reduced Consolidation, Reinstatement, and Renewal of Conditioned Fear Memory by Repetitive Treatment of Radix Polygalae in Mice

Phytotherapy of abnormality of fear memory: A narrative review of mechanisms

It is generally believed that in post-traumatic stress disorder (PTSD), the high expression of fear memory is mainly determined by amygdala hyperactivity and hippocampus hypoactivity. In this review, we firstly updated the mechanisms of fear memory, and then searched the experimental evidence of phytotherapy for fear memory in the past five years. Based on the summary of those experimental studies, we further discussed the future research strategies of plant medicines, including the study of the mechanism of specific brain regions, the optimal time for the prevention and treatment of fear memory-related diseases such as PTSD, and the development of new drugs with active components of plant medicines. Accordingly, plant medicines play a clear role in improving fear memory abnormalities and have the drug development potential in the treatment of fear-related disorders.

Therapeutic Candidates for Alzheimer's Disease: Saponins

Drug development for Alzheimer's disease, the leading cause of dementia, has been a long-standing challenge. Saponins, which are steroid or triterpenoid glycosides with various pharmacological activities, have displayed therapeutic potential in treating Alzheimer's disease. In a comprehensive review of the literature from May 2007 to May 2023, we identified 63 references involving 40 different types of saponins that have been studied for their effects on Alzheimer's disease. These studies suggest that saponins have the potential to ameliorate Alzheimer's disease by reducing amyloid beta peptide deposition, inhibiting tau phosphorylation, modulating oxidative stress, reducing inflammation, and antiapoptosis. Most intriguingly, ginsenoside Rg1 and pseudoginsenoside-F11 possess these important pharmacological properties and show the best promise for the treatment of Alzheimer's disease. This review provides a summary and classification of common saponins that have been studied for their therapeutic potential in Alzheimer's disease, showcasing their underlying mechanisms. This highlights the promising potential of saponins for the treatment of Alzheimer's disease.

Integrated Lipidomics and Network Pharmacology Reveal Mechanism of Memory Impairment Improvement by Yuanzhi San

Memory impairment (MI) is caused by a variety of causes, endangering human health. Yuanzhi San (YZS) is a common prescription used for the treatment of MI, but its mechanism of action needs further exploration. The purpose of this study was to investigate this mechanism through lipidomics and network pharmacology. Sprague Dawley (SD) rats were divided randomly into the normal, model, and YZS groups. The rats were gavaged with aluminum chloride (200 mg/kg) and intraperitoneally injected with D-galactose (400 mg/kg) every day for 60 days, except for the normal group. From the 30th day, YZS (13.34 g/kg) was gavaged once a day to the rats in the YZS group. Post-YZS treatment, ultra-high-performance liquid chromatography-mass spectrometry (UHPLC/MS) analysis was implemented to conduct a lipidomics study in the hippocampus of rats with memory impairment induced by aluminum chloride and D-galactose. Eight differential metabolites were identified between the normal group and the model group, whereas between the model group and the YZS group, 20 differential metabolites were established. Metabolic pathway analysis was performed on the aforementioned lipid metabolites, all of which were involved in sphingolipid and glycerophospholipid metabolism. Furthermore, serum pharmacochemistry analysis of YZS was carried out at the early stage of our research, which discovered 62 YZS prototype components. The results of the network pharmacology analysis showed that they were related to 1030 genes, and 451 disease genes were related to MI. There were 73 intersections between the YZS and MI targets. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that these targets were closely related to the sphingolipid metabolic, calcium signaling, and other pathways. The integrated approach of lipidomics and network pharmacology was then focused on four major targets, including PHK2, GBA, SPTLC1, and AChE, as well as their essential metabolites (glucosylceramide, N-acylsphingosine, phosphatidylserine, phosphatidylcholine, and phosphatidylcholine) and pathways (sphingolipid, glycerophospholipid, and arachidonic acid metabolism). The significant affinity of the primary target for YZS was confirmed by molecular docking. The obtained results revealed that the combination of lipidomics and network pharmacology could be used to determine the effect of YZS on the MI biological network and metabolic state, and evaluate the drug efficacy of YZS and its related mechanisms of action.

Therapeutic potential of Polygala saponins in neurological diseases

BACKGROUND

There are many types of neurological diseases with complex etiologies. At present, most clinical drugs can only relieve symptoms but cannot cure these diseases. Radix Polygalae, a famous traditional Chinese medicine from the root of plants of the genus Polygala, has the traditional effect of treating insomnia, forgetfulness, and palpitation and improving intelligence and other symptoms of neurological diseases. Saponins are important bioactive components of plants of the genus Polygala and exhibit neuroprotective effects.

PURPOSE

This review aimed to summarize the traditional use of Polygala species and discuss the latest phytochemical, pharmacological, and toxicological findings, mainly with regard to Polygala saponins in the treatment of neurological disorders.

METHODS

Literature was searched and collected using databases, including PubMed, Science Direct, CNKI, and Google Scholar. The search terms used included "Polygala", "saponins", "neurological diseases", "Alzheimer's disease", "toxicity", etc., and combinations of these keywords. A total of 1202 papers were retrieved until August 2022, and we included 135 of these papers on traditional uses, phytochemistry, pharmacology, toxicology and other fields.

RESULTS

This literature review mainly reports on the traditional use of the Polygala genus and prescriptions containing Radix Polygalae in neurological diseases. Phytochemical studies have shown that plants of the genus Polygala mainly include saponins, flavonoids, oligosaccharide esters, alkaloids, coumarins, lignans, flavonoids, etc. Among them, saponins are the majority. Modern pharmacological studies have shown that Polygala saponins have neuroprotective effects on a variety of neurological diseases. Its mechanism of action involves autophagic degradation of misfolded proteins, anti-inflammatory, anti-apoptotic, antioxidative stress and so on. Toxicological studies have shown that Polygala saponins trigger gastrointestinal toxicity, and honey processing and glycosyl disruption of Polygala saponins can effectively ameliorate its gastrointestinal side effect.

CONCLUSION

Polygala saponins are the major bioactive components in plants of the genus Polygala that exhibit therapeutic potential in various neurological diseases. This review provides directions for the future study of Polygala saponins and references for the clinical use of prescriptions containing Radix Polygalae for the treatment of neurological diseases.

Clinicians' views on neuromodulation as a treatment for eating disorders: A qualitative study

BACKGROUND

Neuromodulation techniques, such as repetitive transcranial magnetic stimulation (rTMS), transcranial direct current stimulation (tDCS) and deep brain stimulation (DBS), are emerging as promising treatment options in eating disorders (EDs). To date, the views of ED clinicians regarding these interventions have not been explored.

METHODS

Eighteen clinicians were recruited from a specialist ED Service in London, UK. Following a short educational presentation on rTMS, tDCS and DBS, they completed a semi-structured interview to explore their views on the use of these treatment options in EDs.

RESULTS

Clinician knowledge of neuromodulation techniques was low. They raised safety and ethical (particularly capacity to consent) concerns mainly with regard to DBS. Neuromodulation treatments were considered most appropriate as an adjunct to psychotherapy and for patients with severe, enduring illness (who had completed previous psychological treatments).

CONCLUSIONS

Improving clinicians' knowledge and understanding of neuromodulation is fundamental for bridging the gap between research and clinical work. This is especially so given the predominance of psychological theory and practice in the treatment of EDs.

A microemulsion high-performance liquid chromatography (MELC) method for the separation and determination of hydrolyzed tenuifolin in Radix Polygalae

Tenuifolin was used as a reliable chemical marker for the quality control of Radix Polygalae. The determination of tenuifolin is challenging because the analyte molecule lacks a suitable chromophore. The aim of this study was to establish a microemulsion high-performance liquid chromatography (MELC) method which is robust and sensitive, and can separate and determine tenuifolin in Radix Polygalae using an oil-in-water (O/W) microemulsion mobile phase. The separations were performed on a C18 (4.6 × 250 mm, 5 μm) column at 25 °C using a flow rate of 1.0 mL/min, and an ultraviolet detection wavelength of 210 nm. The microemulsion mobile phase comprised 2.8% (w/v) sodium dodecyl sulfate (SDS), 7.0% (v/v) n-butanol, 0.8% (v/v) n-octane and 0.1% (v/v) aqueous orthophosphate buffer (H3PO4). The linearity analysis of tenuifolin showed a correlation coefficient of 0.9923 in the concentration range of 48.00-960.00 µg/mL. The accuracy of the method based on three concentration levels ranged from 96.23% to 99.28%; the limit of detection (LOD) was 2.34 µg/mL, and the limit of quantification (LOQ) was 6.76 µg/mL. The results of our study indicated that the optimized MELC method was sensitive and robust, and can be widely applied for the separation and determination of tenuifolin in Radix Polygalae.