Antidepressant effects of Yuanzhi (Polygalae Radix) extract on chronic unpredictable mild stress-induced depression in rats: modulation of the NLRP3 inflammasome and NF-κB pathway

Objective To investigate the antidepressant effects of Yuanzhi(Polygalae Radix;PR)aqueous extract on chronic unpredictable mild stress(CUMS)-induced depression rat models and the underlying mechanisms.Methods A total of 40 male Sprague Dawley(SD)rats were randomly divided into control;model;low dose of PR(PR-L;0.5 g/kg);high dose of PR(PR-H;1 g/kg);and fluoxetine(10 mg/kg)groups;with 8 rats in each group.Except for the rats in control group;those in the other four groups underwent CUMS-induced depression modeling.PR and fluoxetine were administered intragastrically once daily;30 min prior to the CUMS procedure;for 14 consecu-tive days until the behavioral tests were performed.After CUMS modeling;the sucrose prefer-ence test(SPT);open field test(OFT);novelty-suppressed feeding test(NSFT);forced swim test(FST);and tail suspension test(TST)were employed to assess the pharmacological ef-fects of PR on the mitigation of depressive-like behaviors in rat models.Additionally;the en-zyme-linked immunosorbent assay(ELISA)was utilized to quantify the serum levels of tumor necrosis factor(TNF)-α;interleukin(IL)-6;and IL-1βin the rats.Western blot analysis was al-so conducted to evaluate the protein expression levels of nuclear factor kappa-B(NF-κB);in-ducible nitric oxide synthase(iNOS);cyclooxygenase-2(COX-2);nucleotide-binding oligomerization domain(NOD)-like receptor family pyrin domain containing 3(NLRP3);apoptosis-associated speck-like protein containing caspase recruitment domain(ASC);and caspase-1 in the hippocampal tissues of the rats.Immunofluorescence staining was per-formed to observe the morphological changes in ionized calcium-binding adapter molecule 1 positive(Iba-1+)cells in the dentate gyrus(DG)of rats with CUMS-induced depression.Results(i)Treatment with PR-H and fluoxetine resulted in significant enhancements in both the total distance and time the rats moved during tests(P<0.01 and P<0.05;respectively).Post-administration of PR-H and fluoxetine also led to statistically significant increase in su-crose preference among rats(P<0.05).Besides;PR-L;PR-H;and fluoxetine treatment markedly decreased the latency of ingestion(P<0.05;P<0.05;and P<0.01;respectively).As observed from the FST;PR-L;PR-H;and fluoxetine presented antidepressant effects on rats with CUMS-induced depression;leading to the reduction in time of their immobility(P<0.05;P<0.01;and P<0.01;respectively).The results of TST indicated reduced immobility time in rats receiving PR-H and fluoxetine treatment as well(P<0.01).(ii)Rats in model group showed an increase in the levels of Iba-1+microglia in their left and right brains in compari-son with control group(P<0.01).However;such increase was negated post PR treatment(P<0.01).Treatment with PR-L;PR-H;and fluoxetine considerably reduced the levels of inflam-matory factors(TNF-α;IL-1β;and IL-6;P<0.01).In addition;treatment of PR-L and PR-H ef-fectively counteracted the elevated levels of NLRP3;ASC;and caspase-1;and markedly down-regulated the expression levels of phosphorylated p65(p-p65);COX-2;and iNOS in rats’hip-pocampus(P<0.01).Conclusion Collectively;these findings indicate that PR exerts an antidepressant effect on rats with CUMS-induced depression partially through the modulation of the NLRP3 and NF-κB signaling pathways.

A systematic review on the neuropharmacological activities of Oligosaccharide ester in Polygalae Radix

Polygalae Radix,which has a long history of medical use in traditional Chinese medicine,is multifunctional such as tranquilize mind,relieve swelling and remove phlegm.It has been demonstrated that Polygalae Radix oligosaccharide ester is the main active component which excutes the neuropharmacological activities like antidepression,anti-dementia and neuroprotection.In this review,the chemical structure,pharmacology,pharmacokinetics and processing mechanism of Polygalae Radix oligosaccharide ester are summarized so as to provide reference for its further development and utilization.

Determination of tenuifolin in Polygalae Radix from different regions by RF-HPCE

A simple,low-cost and effective reverse flow-high performance capillary electrophoresis（RF-HPCE）method was developed for the separation and determination of tenuifolin in Polygalae Radix.Through optimization of separation conditions, a buffer of 50 mmol/L borax containing methanol（65：35,v/v）was selected for the separation of analytes.Regression equation revealed good linear relationship between peak area and concentration of the analyte in the range of 0.0563-0.9000 mg/mL （r=0.9988）.The recoveries ranged from 99.50%-104.7%.The results indicated that this method is simple,rapid and accurate. It can be used for the quality control of Polygalae Radix.

Onjisaponin B derived from Radix Polygalae enhances autophagy and accelerates the degradation of mutant α-Synuclein and Huntingtin in PC-12 cells

OBJECTIVE To investigate the autophagic effect of the compounds from the Chinese medicinal herbs,Radix polygalae as a potential neuroprotective agent that enhances the clearance of mutant Huntingtin andα-synuclein in PC-12 cells.METHODS Radix polygalae was extracted with 75%ethanol using refluxing method,and its quality was assayed by UHPLC-TOF-MS.The autophagic effect of Radix polygalae extract,and its major components including polygalacic acid,senegenin and onjisaponin B were investigated using the green fluorescent protein-light chain 3(GFP-LC3)autophagy detection and Western blot platforms for detecting the autophagic markers,GFP-LC3 puncta formation and LC3Ⅱ expression.The degradation of A53Tα-synuclein and the inhibition of α-synuclein oligo merization related to the Parkinson disease were assayed using Western blot and flow cytometer analysis,respectively.While the cytotoxicity and the degradation of the mutant Huntingtin associated with the Huntingtin disease were investigated using MTT method and flow cytometer analysis.RESULTS Radix polygalae ethanol extract and onjisaponin B improved the GFP-LC3 puncta formation and expression of LC3Ⅱ with time and dose manner,and this induction was activated via AMPK-m TOR and Atg 7 gene pathway.Furthermore,the clearance ofα-synuclein and mutant Huntingtin was enhanced via autophagy induction with the treatment of Radix polygalae ethanol extract and onjisaponin B.CONCLUSION Findings in the current study provide detailed insights into the protective mechanism of a novel autophagy inducer,onjisaponin B,which is valuable for further investigation as a new candidate agent for modulating neurodegenerative disorders through the reduction of toxicity and clearance of mutant proteins in the cellular level.

Research Progress of the Liver–Brain Cotreatment of Depression with Supplemented Danzhi Xiaoyao Powder

Traditional Chinese medicine(TCM)has unique advantages in preventing and treating depression based on holistic concepts and syndrome differentiation and treatment.Liver depression and spleen deficiency are the main syndrome of depression.Danzhi Xiaoyao powder has the efficacy of soothing the liver and relieving depression,nourishing blood,and strengthening spleen.Present studies have proven that it has antidepressant efficacy for the syndrome of liver depression and spleen deficiency.The basic research on pharmacodynamic substances has found that the main active ingredients of Danzhi Xiaoyao powder in the treatment of depression include bupleurum saponin,paeonol,gardenoside,angelica polysaccharide,sulfate polysaccharide,paeoniflorin,albiflorin,atractylone,etc.In clinical practice,Danzhi Xiaoyao powder is often modified to make it more suitable according to the characteristics of pathogenesis and changes in the disease condition.Our research group has found that“brain and spirit failure and liver failing to disperse”are the main pathogenesis of depression.Based on the theory of“liver–brain cotreatment,”the treatment principle of“dispersing the liver and relieving depression,strengthening brain and benefiting intelligence”was put forward.On the basis of Danzhi Xiaoyao powder,Shichangpu(Acori Tatarinowii Rhizoma)was added to enlighten the mind and Yuanzhi(Polygalae Radix)to calm the mind and benefit intelligence.The modified Danzhi Xiaoyao powder was formulated,and its clinical effects on depression were remarkable.Animal experiments also confirmed that modified Danzhi Xiaoyao powder can significantly improve the depression-like behavior of depression model rats and the mechanism may be related to the regulation of the hypothalamic–pituitary–adrenal axis,the increase of the content of 5-hydroxytryptamine,and norepinephrine,which provides a reference for the further promotion of the clinical application of modified Danzhi Xiaoyao powder in the treatment of depression.

Neuroprotective mechanism of Kai Xin San: upregulation of hippocampal insulin-degrading enzyme protein expression and acceleration of amyloid-beta degradation

Kai Xin San is a Chinese herbal formula composed of Radix Ginseng, Poria, Radix Polygalae and Acorus Tatarinowii Rhizome. It has been used in China for many years for treating amnesia. Kai Xin San ameliorates amyloid-β （Aβ） induced cognitive dysfunction and is neuroprotective in vivo, but its precise mechanism remains unclear. Expression of insulin-degrading enzyme （IDE）, which degrades Aβ, is strongly correlated with cognitive function. Here, we injected rats with exogenous Aβ42 （200 μM, 5 μL） into the hippocampus and subsequently administered Kai Xin San （0.54 or 1.08 g/kg/d） intragastrically for 21 consecutive days. Hematoxylin eosin and Nissl staining revealed that Kai Xin San protected neurons against Aβ-induced damage. Furthermore, enzyme linked immunosorbent assay, western blot and polymerase chain reaction results showed that Kai Xin San decreased Aβ42 protein levels and increased expression of IDE protein, but not mRNA, in the hippocampus. Our findings reveal that Kai Xin San facilitates hippocampal Aβ degradation and increases IDE expression, which leads, at least in part, to the alleviation of hippocampal neuron injury in rats.

Gas chromatography-mass spectrometry analysis on compounds in volatile oils extracted from Yuan Zhi(Radix Polygalae) and Shi Chang Pu(Acorus Tatarinowii) by supercritical CO_2

OBJECTIVE:To analyze the constituents of volatile oils extracted from Yuan Zhi(Radix Polygalae),Shi Chang Pu(Acorus Tatarinowii),and a mixture of the two herbs.METHODS:The volatile oils were extracted using supercritical fluid extraction(SFE) with CO 2,and the constituents of the volatile oil extracts were analyzed by gas chromatography-mass spectrometry(GC-MS).The relative content of each component was calculated using peak area normalization.RESULTS:The optimized SFE conditions were 45 MPa at 35℃ for 2 h.Twenty-four compounds were identified in the extract from the Yuan Zhi(Radix Polygalae) and Shi Chang Pu(Acorus Tatarinowii) mixture,and six of these had relative contents >1.These compounds were 1,2-dimethoxy-4-(2-propenyl)-benzene;1,2,3-trimethoxy-5-(2-propenyl)-benzene;β-asarone;(Z,Z) 9,12-octadecadienoic acid;(Z) 6-octadecenoic acid;and ethyl oleate.Combination of the herbs increased the number of pharmacologically active substances in the extract and decreased the number of compounds with one benzene ring compared with the extracts from the individual herbs.CONCLUSION:These results indicate there is a synergistic relationship among the compounds in these herbs.