A potential therapeutic effect of saikosaponin C as a novel dual-target anti-Alzheimer agent

Tau Accumulation in the Spinal Cord Contributes to Chronic Inflammatory Pain by Upregulation of IL-1β and BDNF

Microtubule-associated protein Tau is responsible for the stabilization of neuronal microtubules under normal physiological conditions. Much attention has been focused on Tau's contribution to cognition, but little research has explored its role in emotions such as pain, anxiety, and depression. In the current study, we found a significant increase in the levels of p-Tau (Thr231), total Tau, IL-1β, and brain-derived neurotrophic factor (BDNF) on day 7 after complete Freund's adjuvant (CFA) injection; they were present in the vast majority of neurons in the spinal dorsal horn. Microinjection of Mapt-shRNA recombinant adeno-associated virus into the spinal dorsal cord alleviated CFA-induced inflammatory pain and inhibited CFA-induced IL-1β and BDNF upregulation. Importantly, Tau overexpression was sufficient to induce hyperalgesia by increasing the expression of IL-1β and BDNF. Furthermore, the activation of glycogen synthase kinase 3 beta partly contributed to Tau accumulation. These findings suggest that Tau in the dorsal horn could be a promising target for chronic inflammatory pain therapy.

The therapeutic effects of saikosaponins on depression through the modulation of neuroplasticity: From molecular mechanisms to potential clinical applications

Depression is a major global health issue that urgently requires innovative and precise treatment options. In this context, saikosaponin has emerged as a promising candidate, offering a variety of therapeutic benefits that may be effective in combating depression. This review delves into the multifaceted potential of saikosaponins in alleviating depressive symptoms. We summarized the effects of saikosaponins on structural and functional neuroplasticity, elaborated the regulatory mechanism of saikosaponins in modulating key factors that affect neuroplasticity, such as inflammation, the hypothalamic-pituitary-adrenal (HPA) axis, oxidative stress, and the brain-gut axis. Moreover, this paper highlights existing gaps in current researches and outlines directions for future studies. A detailed plan is provided for the future clinical application of saikosaponins, advocating for more targeted researches to speed up its transition from preclinical trials to clinical practice.

Highly sensitive indirect competitive enzyme-linked immunosorbent assay based on a monoclonal antibody against saikosaponin b2 for quality control of Kampo medicines containing Bupleuri radix

Saikosaponins are naturally occurring oleanane-type triterpenoids that are found in Bupleuri radix (root of Bupleurum falcatum) and exhibit a broad biological activity spectrum. Saikosaponin b2 (SSb2) is the main saikosaponin in Kampo medicine extracts and is a designated quality control marker for the same in the Japanese Pharmacopeia. Although some monoclonal antibodies (mAbs) against saikosaponins have been produced to evaluate the quality of Bupleuri radix and related products, anti-SSb2 mAbs have not been used to quantify SSb2 in Kampo medicines. To address this knowledge gap, we herein established a new hybridoma cell line secreting a highly specific anti-SSb2 mAb and developed an indirect competitive enzyme-linked immunosorbent assay (icELISA) based on this mAb for the detection of SSb2 in Bupleuri radix-containing Kampo medicines. The generated SSb2-recognized mAb exhibited high specificity to SSb2 in icELISA. The developed assay featured high sensitivity (linearity range = 1.95-125 ng/ml), accuracy, precision and reproducibility (coefficient of variation < 5%), and the thus determined SSb2 contents were strongly correlated with those obtained using liquid chromatograph-mass spectrometer. These results suggest that the anti-SSb2 mAb-based icELISA method can be used for the quality control and standardization of Kampo medicines containing Bupleuri radix.

Reduced risk of dementia in patients with type 2 diabetes mellitus using Chinese herbal medicine: A nested case-control study

BACKGROUND

Dementia is a prevalent condition in type 2 diabetes mellitus (T2DM) patients. While Chinese herbal medicine (CHM) is often employed as complementary therapy for glycemic control, its effect in controlling likelihood of dementia has not yet been fully elucidated.

AIM

To compare the risk of dementia between T2DM patients with and without CHM treatment.

METHODS

We undertook a nested case-control study and obtained data on patients 20-70 years of age who received medical care for T2DM between 2001 and 2010 from the National Health Insurance Research database in Taiwan. Cases, defined as those with dementia that occurred at least one year after the diagnosis of T2DM, were randomly matched to controls without dementia from the study cohort at a 1:1 ratio. We applied conditional logistic regression to explore the associations between CHM treatment and dementia.

RESULTS

A total of 11699 dementia cases were matched to 11699 non-dementia controls. We found that adding CHM to conventional care was related to a lower risk of dementia [adjusted odds ratio (OR) = 0.51], and high-intensity CHM treatment was associated with an adjusted OR of 0.22.

CONCLUSION

This study shows that the cumulative CHM exposure was inversely associated with dementia risk in an exposure-response manner, implying that CHM treatment may be embraced as a disease management approach for diabetic patients to prevent dementia.

Chaihu Shugan San ameliorated cognitive deficits through regulating gut microbiota in senescence-accelerated mouse prone 8

Background: Traditional Chinese medicines exhibit promising preventive effects on Alzheimer's disease. Chaihu Shugan San (CSS) is a well-known traditional herbal formula whose several kinds of ingredients have the potential of ameliorating Alzheimer's disease. The present study aimed to evaluate the effects of CSS on the microbiota-gut-brain axis and cognitive deficits of senescence-accelerated mouse prone 8 (SAMP8) mice as well as investigate the underlying mechanisms. Methods: Thirty 5-month-old SAMP8 mice were randomly divided into the model group (SAMP8), CSS low-dose treatment group (CSSL), and CSS high-dose treatment group (CSSH). Ten SAMR1 mice were used as the normal control, and ten SAMP8 mice treated with donepezil were used as the positive control of cognitive function. CSS was orally administrated to SAMP8 mice for 8 weeks. The Morris water maze test was used to evaluate cognitive function. Histological staining was used to observe neuronal injury and Aβ deposition. Transmission electron microscopy was used to observe the synaptic ultrastructure. 16S rRNA gene analysis was performed to measure the changes in intestinal microbiota. Results: The results showed that CSS significantly improved the learning function and memory deficits of aged SAMP8 mice in the Morris water maze examination. CSS ameliorated neuronal injury, synaptic injuries, and Aβ deposition in the brain of SAMP8 mice. In addition, CSS also significantly improved microbiota composition in terms of elevating Lactobacillus reuteri and decreasing Staphylococcus xylosus in the feces of aged SAMP8 mice. Conclusion: These findings suggested that CSS might have a preventive potential for cognitive deficits in aging through regulating gut microbiota, which paved the way for the application of CSS for prevention and therapeutic purposes for mild cognitive impairment as well as Alzheimer's disease.

Inhibition of IL-6 methylation by Saikosaponin C regulates neuroinflammation to alleviate depression

PURPOSE

Saikosaponin C (SSc) increases the expression of synaptic proteins and has a unexplored role in the prevention of AD and other neurodegeneration in humans. Therefore, we hypothesized that SSc has the potential to relief of depressive symptoms. Here, our study assessed the role of SSc on depression-like behaviors caused by a chronic social defeat stress (CSDS) in mice and explored the underlying mechanisms.

METHODS

Behavioral tests were conducted to verify the efficacy of SSC in treating depression-like behavior in mice. The levels of IL-6, TNF-α and IL-1β in brain tissue and BV2 cells were determined by ELISA. The effect of SSc on dendritic spine density was determined by Golgi staining. The percentage of monocytes in peripheral blood was measured using flow cytometry. The levels of STAT3 and DNMT1 under the influence of SSc were assessed by immunofluorescence. Protein expression of DNMT1, DNMT3a, DNMT3b, p-STAT3 and STAT3 in brain and BV2 cells was studied by Western blot. OE-DNMT1 was induced in the experiment to verify the inhibitory effect of DNMT1 on IL-6 methylation in SSC. Luciferase was used to detect SSC specific fragments affecting IL-6 methylation.

RESULT

SSC treatment significantly alleviated depressive-like behavior, inhibited the levels of inflammatory cytokines including IL-6, IL-1β and TNF-α, increased dendritic spine density and promoted synaptic plasticity in mice. SSC downregulated IL-6, STAT3 and DNMT1 expression in vivo and in vitro. SSC also decreased the percentage of monocytes in peripheral blood and suppressed neuroinflammation in mice. Overexpression of DNMT1 by shRNA abolished the inhibitory effect of SSc on IL-6 methylation.

CONCLUSION

This study showed that SSc reduced IL6 methylation by inhibiting DNMT1 protein, induced a decrease in IL6 expression, promoted synaptic plasticity, and attenuated CSDS-induced depression-like behavior.

Sinisan alleviates depression-like behaviors by regulating mitochondrial function and synaptic plasticity in maternal separation rats

BACKGROUND

Sinisan (SNS) consists of four kinds of herbs, which is the core of antidepressant prescription widely used in traditional Chinese medicine clinic treatment for depression induced by early life stress. However, the role and precise mechanism of SNS antidepressant have not yet been elucidated.

PURPOSE

This study aimed to investigate the mechanism SNS on antidepressant of regulating mitochondrial function to improve hippocampal synaptic plasticity.

METHODS

90 Sprague-Dawley (SD) rats male pups on Post-Natal Day (PND) 0 were randomly divided into Control group (ddH₂0), Model group (ddH₂0), Fluoxetine group (5.0 mg/kg fluoxetine), and SNS-L group (2.5 g/kg SNS), SNS-M group (5.0 g/kg SNS) and SNS-H group (10.0 g/kg SNS), 15 animals per group. Maternal separation (MS) from PND1 to PND21, drug intervention from PND60 to PND90, and behavior tests including sucrose preference test, open field test and forced swimming test from PND83 to PND90 were performed. Synaptic structure and mitochondrial structure were observed by TEM. The expression levels of PSD-95 and SYN were detected by immunohistochemistry and western blot test, the adenosine triphosphate (ATP) content in the hippocampus was detected by assay kits, and the expression levels of Mfn2, Drp1 and Fis1 protein were detected by western bolt test.

RESULTS

SNS can alleviate depression-like and anxiety-like behaviors in MS rats, improve the damage of synapses and mitochondria, reduce the decrease of ATP in hippocampus, and reverse the expression levels of PSD-95, SYN, Mfn2, Drp1, and Fis1 proteins.

CONCLUSION

SNS reduced the risk of early life stress induced depression disorder via regulating mitochondrial function and synaptic plasticity. Targeting mitochondrial may be a novel prospective therapeutic avenue for antidepressant.

Therapeutic effects of total saikosaponins from Radix bupleuri against Alzheimer’s disease

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by memory loss and cognitive dysfunction in the elderly, with amyloid-beta (Aβ) deposition and hyperphosphorylation of tau protein as the main pathological feature. Nuclear factor 2 (Nrf2) is a transcription factor that primarily exists in the cytosol of hippocampal neurons, and it is considered as an important regulator of autophagy, oxidative stress, and inflammation. Total saikosaponins (TS) is the main bioactive component of Radix bupleuri (Chaihu). In this study, it was found that TS could ameliorate cognitive dysfunction in APP/PS1 transgenic mice and reduce Aβ generation and senile plaque deposition via activating Nrf2 and downregulating the expression of β-secretase 1 (BACE1). In addition, TS can enhance autophagy by promoting the expression of Beclin-1 and LC3-II, increasing the degradation of p62 and NDP52 and the clearance of phosphorylated tau (p-tau), and reducing the expression of p-tau. It can also downregulate the expression of nuclear factor-κB (NF-κB) to inhibit the activation of glial cells and reduce the release of inflammatory factors. In vitro experiments using PC12 cells induced by Aβ, TS could significantly inhibit the aggregation of Aβ and reduce cytotoxicity. It was found that Nrf2 knock-out weakened the inhibitory effect of TS on BACE1 and NF-κB transcription in PC12 cells. Moreover, the inhibitory effect of TS on BACE1 transcription was achieved by promoting the binding of Nrf2 and the promoter of BACE1 ARE1. Results showed that TS downregulated the expression of BACE1 and NF-κB through Nrf2, thereby reducing the generation of Aβ and inhibiting neuroinflammation. Furthermore, TS can ameliorate synaptic loss and alleviate oxidative stress. In gut microbiota analysis, dysbiosis was demonstrated in APP/PS1 transgenic mice, indicating a potential link between gut microbiota and AD. Furthermore, TS treatment reverses the gut microbiota disorder in APP/PS1 mice, suggesting a therapeutic strategy by remodeling the gut microbe. Collectively, these data shows that TS may serve as a potential approach for AD treatment. Further investigation is needed to clarify the detailed mechanisms underlying TS regulating gut microbiota and oxidative stress.

Saikogenin F From Bupleurum smithii Ameliorates Learning and Memory Impairment via Antiinflammation Effect in an Alzheimer’s Disease Mouse Model

Alzheimer's disease (AD) is the most common neurodegenerative disease associated with aging. Bupleurum smithii Wolff. is a Chinese folk medicine used to reduce fever and inflammation. Regarding the key role of neuroinflammation in AD pathogenesis, it was speculated that B. smithii may be the source of compounds that treat AD through anti-inflammatory effects. This study aimed to investigate the effects of saikogenin F, a natural active ingredient from B. smithii, on cognition impairment and neuroinflammation in AD mice induced by amyloid β (Aβ). The AD mice model was established by intracerebroventricular (i.c.v.) injection of Aβ, and different doses of saikogenin F (10, 20, and 40 mg/kg) were intragastrically administrated once daily. Results of behavioral experiments, including the novel object recognition (NOR) test, Y-maze test, and Morris water maze (MWZ) test, showed that saikogenin F could ameliorate Aβ-induced cognition impairment in AD mice. Enzyme linked immunosorbent assay (ELISA) results showed that tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and reactive oxygen species (ROS) levels in hippocampal tissue increased after Aβ injection, while saikogenin F could significantly reduce the concentrations of these inflammatory factors. Western blotting results revealed that the Aβ-induced reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits protein expression in mice hippocampus was remarkably downregulated by saikogenin F. Results of Iba-1 immunohistochemical staining showed that saikogenin F could effectively inhibit Aβ-induced activation of microglia in vivo. These results suggested that saikogenin F could relieve Aβ-induced cognitive impairment via inhibiting neuroinflammation and microglial activation. These effects may be achieved by inhibiting the expression of the NADPH oxidase subunits gp91phox and p47phox.

Saikosaponins: A Review of Structures and Pharmacological Activities

Radix Bupleuri is a traditional medicine widely used in China and other Asian countries. Phytochemistry and pharmacology study reveal that saikosaponins(SSs) are the main bioactive compounds in Radix Bupleuri. SSs are complex compounds composed of triterpene aglycone and carbohydrate part containing 1-13 monosaccharides, which can be divided into seven types based on their structural characteristics. Many different kinds of SSs have been isolated from plants of Bupleurum L. SSs show a variety of biological activities, such as central nervous system protection, liver protection, antivirus, anti-tumor, anti-inflammation, hormone-like effects, and immune regulation functions. Due to their broad activity and favorable safety profile, SSs attract an increasing amount of attention in recent years. In this review, the structures of 86 SSs are summarized based on the different aglycones due to the diverse structures of saikosaponin(SS). The pharmacological effects and related mechanism of SSs are thoroughly reviewed, and perspectives for future research are further discussed.

BACE1 Overexpression Reduces SH-SY5Y Cell Viability Through a Mechanism Distinct from Amyloid-β Peptide Accumulation: Beta Prime-Mediated Competitive Depletion of sAβPPα

BACKGROUND

The Alzheimer's disease (AD)-associated amyloid-beta protein precursor (AβPP) can be cleaved by β-site AβPP cleaving enzyme 1 (BACE1) and the γ-secretase complex to yield neurotoxic amyloid-β (Aβ) peptides. However, AβPP can also be cleaved in a 'non-amyloidogenic' manner either by α-secretase to produce soluble AβPP alpha (sAβPPα) (a fragment with neuroprotective/neurogenic functions) or through alternative BACE1-mediated 'beta prime' activity yielding soluble AβPP beta prime (sAβPPβ').

OBJECTIVE

To determine whether sAβPPα depletion, as opposed to Aβ peptide accumulation, contributes to cytotoxicity in AD-relevant SH-SY5Y neuroblastoma cell models.

METHODS

AβPP proteolysis was characterized by immunoblotting in mock-, wild-type AβPP (wtAβPP)-, BACE1-, and Swedish mutant AβPP (SweAβPP)-transfected cells. AβPP beta prime cleavage was confirmed through secretase inhibitor studies and C-terminal fragment analysis. The roles of sAβPPα and sAβPPβ' in cell viability were confirmed by overexpression studies.

RESULTS

Despite producing enhanced Aβ peptide levels, wtAβPP- and SweAβPP-transfected cells did not exhibit reduced viability whereas BACE1-transfected cells did. sAβPPα generation in SH-SY5Y-BACE1 cells was virtually ablated in lieu of BACE1-mediated sAβPPβ' production. sAβPPα overexpression in SH-SY5Y-BACE1 cells restored viability whereas sAβPPβ' overexpression decreased viability further. The anti-AβPP 6E10 antibody was shown to cross-react with sAβPPβ'.

CONCLUSION

sAβPPα depletion and/or sAβPPβ' accumulation, but not elevated Aβ peptide levels, represent the cytotoxic mechanism following BACE1 overexpression in SH-SY5Y cells. These data support the novel concept that competitive sAβPPα depletion by BACE1 beta prime activity might contribute to AD. The cross-reactivity of 6E10 with AβPPβ'also questions whether previous studies assessing sAβPPα as a biomarker using this antibody should be revisited.

Quantitative 1H NMR for the Direct Quantification of Saikosaponins in Bupleurum chinense DC

Saikosaponin a and saikosaponin d are used as chemical standards for the quality evaluation of Bupleurum chinense DC. by the high-performance liquid chromatography method in current Chinese Pharmacopoeia. However, other saikosaponins, such as saikosaponin c and saikosaponin b₂, also possess pharmaceutical activity, but are not used as chemical standards. In this study, a quantitative proton nuclear magnetic resonance (¹H NMR) method was developed to determine the total mass percentage (mg/g) of SSa, SSb₁, SSb₂ and SSd in B. chinense DC., using the H-24 (δ_H 0.71) signal. Furthermore, the molality (mol/kg) of type I saikosaponins (epoxy-ether structure) was also determined by quantitative ¹H NMR in the area of H-11 (δ_H 5.95) for a more accurate quality evaluation. Validation of the method confirmed that it has acceptable selectivity, precision, stability, and repeatability. The results indicated that this method has the potential to be a reliable method for the quantification of saikosaponins in Bupleurum scorzonerifolium Willd., vinegar baked B. chinense DC. and B. scorzonerifolium Willd., Chaihu Koufuye (oral liquid of Chaihu).

Cognitive improvements and reduction in amyloid plaque deposition by saikosaponin D treatment in a murine model of Alzheimer's disease

Alzheimer's disease (AD), is a severe neurodegenerative disease that currently lacks an optimally effective therapeutic agent for its management. Saikosaponin D (SSD) is a component extracted from the herb Bupleurum falcatum that is commonly used in Chinese medicine. Although SSD has been reported to exert neuroprotective effects, its pharmacological role in AD has not been previously elucidated. Therefore, the aim of the present study was to investigate whether SSD treatment improves the cognitive function and pathological features of 3xTg mice, a triple-transgenic mouse model of AD that displays classical pathological features of AD. The effects of SSD treatment on the behavioral, histological and physiological features of the animal were quantified. Results from the behavioral experiments on the SSD-treated 3xTg mice identified a significant reduction in memory impairment. In addition, histological staining results indicated that SSD application could preserve the morphology of neurons, reduce apoptosis and significantly inhibit amyloid-β deposition in the hippocampus of 3xTg mice. SSD treatment also decelerated the activation of microglia and astrocytes in the hippocampus of 3xTg mice, possibly via the inhibition of the NF-κB signal transduction pathway. Therefore, the present study demonstrated the protective effects of SSD against progressive neurodegeneration and identified the potential underlying pharmacological mechanism. It was speculated that SSD may serve as a possible therapeutic agent in AD treatment in the future.

Research Progress on Classical Traditional Chinese Medicine Jieyu Pills in the Treatment of Depression

Depression is a common clinical psychological disease, which is called "yu zheng" in traditional Chinese medicine (TCM). TCM has a long history in the treatment of depression (yu zheng), which has unique advantages. Jieyu pill (JYP), a classical TCM formula, has been widely used for treating depression because of its clear clinical efficacy, low side effects, and high compliance. In this review, we systematically introduce recent clinical and animal experimental studies on JYP and depression, and review the pharmacological mechanism and active ingredients of JYP, as well as its clinical application in depression therapy. This systematic review provides a deep understanding of TCM prescriptions, pharmacological mechanisms, and disease-medicine interactions, and lays the foundation for developing new treatments for depression.

A combined molecular biology and network pharmacology approach to investigate the multi-target mechanisms of Chaihu Shugan San on Alzheimer's disease

Chaihu Shugan San (CSS) is a well-known herbal formula used to nourish liver and blood, promote blood circulation and Qi flow in Traditional Chinese Medicine. Modern pharmacological studies and clinical uses showed that CSS could ameliorate cognitive dysfunction of Alzheimer's disease (AD). The present study aimed to elucidate the multi-target mechanisms of CSS on AD using network pharmacology analysis and verify its effect by biological experiments. Firstly, a total of 152 active compounds in CSS, 520 predicted biological targets and 160 AD-related targets were identified. Subsequently, the networks including herb-compound-target network, AD-target network, and CSS potential target-AD target network were constructed. 60 key targets highly responsible for the beneficial effect of CSS on AD were identified by central network topological analysis. They were significantly characterized as nuclear or cytoplasmic proteins with molecular function of protein binding. They were also enriched in various biological processes through PI3K-Akt signaling pathway, MAPK signaling pathway and HIF signaling pathway by GO function and KEGG pathway enrichment analysis. Pretreatment with CSS ameliorated Aβ-induced neural cell death and reduced the number of apoptotic cells in differentiated PC12 cells. Moreover, increased phosphorylation of Akt accompanied with decreased Bax expression was found after CSS pretreatment, suggesting that Akt signaling pathway was involved in the protective effect of CSS against neural cells death. The present study systematically revealed the multi-target mechanisms of CSS on AD using network pharmacology approach, as well as validated the protective effect of CSS against Aβ-induced neural cells death through Akt signaling pathway. It provided indications for further mechanistic studies and also for the development of CSS as a potential treatment for AD patients.

A reliable LC-MS/MS method for the quantification of five bioactive saponins of crude and processed Bupleurum scorzonerifolium in rat plasma and its application to a pharmacokinetic study

A simple and reliable liquid chromatography-mass spectrometry (LC-MS) method was developed for simultaneous determination of saikosaponin A, saikosaponin B₁ , saikosaponin C, saikosaponin D and saikosaponin F in rat plasma using glycyrrhetinic acid as an internal standard (IS). The separation was operated on a Waters BEH C₁₈ column. The mobile phases of gradient elution consisted of acetonitrile (A) and 0.1% aqueous acetic acid (B). The mass spectrometric detection was accomplished in multiple reaction monitoring mode. The five saponins displayed good linearity (r²  > 0.9996). The lower limits of quantitation of saikosaponin A, saikosaponin B₁ , saikosaponin C, saikosaponin D and saikosaponin F were determined to be 2.9, 2.3, 3.5, 2.9 and 3.1 ng/mL, respectively. Moreover, the intra- and inter-day precisions of the five saponins showed an RSD within 2.96%, whereas the accuracy (RE) ranged from -2.28 to 2.78%. Finally, the developed method was fully validated and applied to a comparative pharmacokinetic study of the five bioactive saponins in rats following oral administration of crude and vinegar-processed Bupleurum scorzonerifolium.

Localization of malonyl and acetyl on substituted saikosaponins according to the full-scan mass spectra and the fragmentation of sodium-adduct ions in the positive mode

RATIONALE

Discriminating between aglycone-substituted and saccharide-substituted saikosaponins by liquid chromatography/tandem mass spectrometry (LC/MSⁿ ) is a long-standing issue that is still to be resolved. It is necessary to characterize the two types of substituted saikosaponins taking into consideration the potential significant difference in their bioactivity.

METHODS

Taking the substituents malonyl and acetyl as examples, we developed a MS strategy to discriminate between the aglycone-substituted and saccharide-substituted saikosaponins through comparing their Y₀  - nH₂ O (n = 1-2) ions from the protonated molecules in the full-scan mass spectra and their B ions in the MS² spectra of sodium-adduct molecules in the positive mode.

RESULTS

The deprotonated molecules of the aglycone-substituted saikosaponins presented similar fragmentation patterns to those of saccharide-substituted ones in the negative mode, which could not discriminate whether the substitutes were located on the aglycone or the saccharide. In contrast, the Y₀  - nH₂ O (n = 1-2) ions containing or no substituent were observed respectively in the mass fragmentation of the protonated molecules of aglycone-substituted or saccharide-substituted saikosaponins in the positive mode. In addition, the B ions containing or no substituent were observed respectively in the mass fragmentation of the sodium-adduct molecules of the saccharide-substituted or aglycone-substituted saikosaponins in the positive mode. Two aglycone-malonylated saikosaponins were reported for the first time.

CONCLUSIONS

Whether the substituents were located on the aglycone or the saccharide could be determined according to the Y₀  - nH₂ O (n = 1-2) ions from the protonated molecules in the full-scan mass spectra and the B ions in the MS² spectra of sodium-adduct molecules in the positive mode. Our results have updated the mass fragmentation patterns of substituted saikosaponins, which is helpful for the quality control of pharmaceutical preparations containing saikosaponins. More importantly, this MS strategy should be able to be extended to characterize other substituted saponins of bioactive significance in future studies.

Traditional Oriental Medicines and Alzheimer's Disease

Alzheimer’s disease (AD), which is the most major cause of dementia, is a progressive neurodegenerative disease that affects cognitive functions. Even though the prevalence of AD is continuously increasing, few drugs including cholinesterase inhibitors and N-methyl D-aspartate-receptor antagonists were approved to treat AD. Because the clinical trials of AD drugs with single targets, such as β-amyloid and tau, have failed, the development of multi-target drugs that ameliorate many of the symptoms of AD is needed. Thus, recent studies have investigated the effects and underlying mechanisms of herbal formulae consisting of various herb combinations used to treat AD. This review discusses the results of clinical and nonclinical studies of the therapeutic efficacy in AD and underlying mechanisms of the herbal formulae of traditional Oriental medicines and bioactive compounds of medicinal plants.

Recent Expansions on Cellular Models to Uncover the Scientific Barriers Towards Drug Development for Alzheimer's Disease

Globally, the central nervous system (CNS) disorders appear as the most critical pathological threat with no proper cure. Alzheimer's disease (AD) is one such condition frequently observed with the aged population and sometimes in youth too. Most of the research utilizes different animal models for in vivo study of AD pathophysiology and to investigate the potency of the newly developed therapy. These in vivo models undoubtably provide a powerful investigation tool to study human brain. Although, it sometime fails to mimic the exact environment and responses as the human brain owing to the distinctive genetic and anatomical features of human and rodent brain. In such condition, the in vitro cell model derived from patient specific cell or human cell lines can recapitulate the human brain environment. In addition, the frequent use of animals in research increases the cost of study and creates various ethical issues. Instead, the use of in vitro cellular models along with animal models can enhance the translational values of in vivo models and represent a better and effective mean to investigate the potency of therapeutics. This strategy also limits the excessive use of laboratory animal during the drug development process. Generally, the in vitro cell lines are cultured from AD rat brain endothelial cells, the rodent models, human astrocytes, human brain capillary endothelial cells, patient derived iPSCs (induced pluripotent stem cells) and also from the non-neuronal cells. During the literature review process, we observed that there are very few reviews available which describe the significance and characteristics of in vitro cell lines, for AD investigation. Thus, in the present review article, we have compiled the various in vitro cell lines used in AD investigation including HBMEC, BCECs, SHSY-5Y, hCMEC/D3, PC-2 cell line, bEND3 cells, HEK293, hNPCs, RBE4 cells, SK-N-MC, BMVECs, CALU-3, 7W CHO, iPSCs and cerebral organoids cell lines and different types of culture media such as SCM, EMEM, DMEM/F12, RPMI, EBM and 3D-cell culture.

A comprehensive review and perspectives on pharmacology and toxicology of saikosaponins

BACKGROUND

Radix Bupleuri (RB) has been widely used in Chinese Traditional Medicine for over 2000 years and is currently marketed in China as Chai-Hu-Shu-Gan tablets and Xiao-Yao-Wan tablets. Saikosaponins (SSs, especially SSa, SSc and SSd), as the major bioactive compounds in RB, represent anti-inflammatory, anti-tumor, anti-oxidant, anti-viral and hepatoprotective effects.

PURPOSE

To summarize recent findings regarding to the extraction, detection, biosynthesis, metabolism, pharmacological/toxicological effects of SSs.

METHODS

Online academic databases (including PubMed, Google Scholar, Web of Science and CNKI) were searched using search terms of "Saikosaponin", "Radix Bupleuri", "Bupleurum" and combinations to include published studies of SSs primarily from 2003 to 2018. Several critical previous studies beyond this period were also included.

RESULTS

354 papers were found and 165 papers were reviewed. SSs have drawn great attention for their anti-inflammation, anti-viral and anti-cancer effects and contradictory roles in the regulation of cell apoptosis, oxidative stress and liver fibrosis. Meanwhile, increased risks of overdose-induced acute or accumulation-related chronic hepatotoxicity of SSs and RB have also been reported. However, underlying mechanisms of SSs bioactivities, the metabolism of SSs and bioactivities of SSs metabolites are largely unknown.

CONCLUSION

This comprehensive review of SSs provides novel insights and perspectives on the limitations of current studies and the importance of metabolism study and the dose-pharmacological/toxic relationship of SSs for the future discovery of SSs-based therapeutic strategies and clinical safe practice.

A comprehensive review and perspectives on pharmacology and toxicology of saikosaponins

BACKGROUND

Radix Bupleuri (RB) has been widely used in Chinese Traditional Medicine for over 2000 years and is currently marketed in China as Chai-Hu-Shu-Gan tablets and Xiao-Yao-Wan tablets. Saikosaponins (SSs, especially SSa, SSc and SSd), as the major bioactive compounds in RB, represent anti-inflammatory, anti-tumor, anti-oxidant, anti-viral and hepatoprotective effects.

PURPOSE

To summarize recent findings regarding to the extraction, detection, biosynthesis, metabolism, pharmacological/toxicological effects of SSs.

METHODS

Online academic databases (including PubMed, Google Scholar, Web of Science and CNKI) were searched using search terms of "Saikosaponin", "Radix Bupleuri", "Bupleurum" and combinations to include published studies of SSs primarily from 2003 to 2018. Several critical previous studies beyond this period were also included.

RESULTS

354 papers were found and 165 papers were reviewed. SSs have drawn great attention for their anti-inflammation, anti-viral and anti-cancer effects and contradictory roles in the regulation of cell apoptosis, oxidative stress and liver fibrosis. Meanwhile, increased risks of overdose-induced acute or accumulation-related chronic hepatotoxicity of SSs and RB have also been reported. However, underlying mechanisms of SSs bioactivities, the metabolism of SSs and bioactivities of SSs metabolites are largely unknown.

CONCLUSION

This comprehensive review of SSs provides novel insights and perspectives on the limitations of current studies and the importance of metabolism study and the dose-pharmacological/toxic relationship of SSs for the future discovery of SSs-based therapeutic strategies and clinical safe practice.

A comprehensive review and perspectives on pharmacology and toxicology of saikosaponins

BACKGROUND

Radix Bupleuri (RB) has been widely used in Chinese Traditional Medicine for over 2000 years and is currently marketed in China as Chai-Hu-Shu-Gan tablets and Xiao-Yao-Wan tablets. Saikosaponins (SSs, especially SSa, SSc and SSd), as the major bioactive compounds in RB, represent anti-inflammatory, anti-tumor, anti-oxidant, anti-viral and hepatoprotective effects.

PURPOSE

To summarize recent findings regarding to the extraction, detection, biosynthesis, metabolism, pharmacological/toxicological effects of SSs.

METHODS

Online academic databases (including PubMed, Google Scholar, Web of Science and CNKI) were searched using search terms of "Saikosaponin", "Radix Bupleuri", "Bupleurum" and combinations to include published studies of SSs primarily from 2003 to 2018. Several critical previous studies beyond this period were also included.

RESULTS

354 papers were found and 165 papers were reviewed. SSs have drawn great attention for their anti-inflammation, anti-viral and anti-cancer effects and contradictory roles in the regulation of cell apoptosis, oxidative stress and liver fibrosis. Meanwhile, increased risks of overdose-induced acute or accumulation-related chronic hepatotoxicity of SSs and RB have also been reported. However, underlying mechanisms of SSs bioactivities, the metabolism of SSs and bioactivities of SSs metabolites are largely unknown.

CONCLUSION

This comprehensive review of SSs provides novel insights and perspectives on the limitations of current studies and the importance of metabolism study and the dose-pharmacological/toxic relationship of SSs for the future discovery of SSs-based therapeutic strategies and clinical safe practice.

UPLC-MS/MS Method for the Determination of 14 Compounds in Rat Plasma and Its Application in a Pharmacokinetic Study of Orally Administered Xiaoyao Powder

Xiaoyao Powder (XYP), a common Chinese medicine, comprises eight traditional Chinese herbs and has been widely used clinically to treat liver damage and mental disorders. An ultra-performance liquid chromatography–tandem mass spectrometry method was developed to investigate the pharmacokinetics of 14 compounds (albiflorin, paeoniflorin, ferulic acid, senkyunolide I, quercetin, isoliquiritigenin, atractylenolide III, ligustilide, atractylenolide II, liquiritin, liquiritigenin, saikosaponin c, glycyrrhizic acid, and saikosaponin a) in XYP. Naringenin was used as the internal standard. The compounds were separated using an ACQUITY UPLC^TM BEH C18 column (1.7 μm, 50 × 2.1 mm) with a mobile phase consisting of acetonitrile and 0.1% formic acid in water at a flow rate of 0.3 mL/min. Detection was performed on a triple-quadrupole tandem mass spectrometer using multiple reaction monitoring and an electrospray ionization source in both positive and negative ionization modes. All calibration curves exhibited good linearity (r² > 0.9974) over the measured ranges. The intra- and inter-day precisions were within 12%, and the accuracy ranged from 89.93% to 106.64%. Extraction recovery and matrix effect results were satisfactory. The method was successfully applied in a pharmacokinetic study of the 14 compounds in rat plasma after the oral administration of XYP.

Molecular Mechanisms Involved in Oxidative Stress-Associated Liver Injury Induced by Chinese Herbal Medicine: An Experimental Evidence-Based Literature Review and Network Pharmacology Study

Oxidative stress, defined as a disequilibrium between pro-oxidants and antioxidants, can result in histopathological lesions with a broad spectrum, ranging from asymptomatic hepatitis to hepatocellular carcinoma in an orchestrated manner. Although cells are equipped with sophisticated strategies to maintain the redox biology under normal conditions, the abundance of redox-sensitive xenobiotics, such as medicinal ingredients originated from herbs or animals, can dramatically invoke oxidative stress. Growing evidence has documented that the hepatotoxicity can be triggered by traditional Chinese medicine (TCM) during treating various diseases. Meanwhile, TCM-dependent hepatic disorder represents a strong correlation with oxidative stress, especially the persistent accumulation of intracellular reactive oxygen species. Of note, since TCM-derived compounds with their modulated targets are greatly diversified among themselves, it is complicated to elaborate the potential pathological mechanism. In this regard, data mining approaches, including network pharmacology and bioinformatics enrichment analysis have been utilized to scientifically disclose the underlying pathogenesis. Herein, top 10 principal TCM-modulated targets for oxidative hepatotoxicity including superoxide dismutases (SOD), malondialdehyde (MDA), glutathione (GSH), reactive oxygen species (ROS), glutathione peroxidase (GPx), Bax, caspase-3, Bcl-2, nuclear factor (erythroid-derived 2)-like 2 (Nrf2), and nitric oxide (NO) have been identified. Furthermore, hepatic metabolic dysregulation may be the predominant pathological mechanism involved in TCM-induced hepatotoxic impairment.

The Role of Saikosaponins in Therapeutic Strategies for Age-Related Diseases

As life expectancy increases, elderly populations tend to spend an increasing number of years in poor health, with chronic age-related diseases and disability. Therefore, the development of therapeutic strategies to treat or prevent multiple pathophysiological conditions in the elderly may improve health-adjusted life expectancy and alleviate the potential economic and social burdens arising from age-related diseases. Bioactive natural products might represent promising new drug candidates for the treatment of many chronic age-related diseases, including cancer, Alzheimer's disease, cardiovascular disease, obesity, and liver disease. Here, we discuss a therapeutic option using saikosaponins, which are triterpene saponins isolated from Bupleurum, against a variety of age-related diseases. Understanding the underlying mechanisms of natural products like saikosaponins in the treatment of age-related diseases may help in the development of diverse natural product-derived compounds that may be effective against a number of chronic health problems.

Radix Bupleuri: A Review of Traditional Uses, Botany, Phytochemistry, Pharmacology, and Toxicology

Radix Bupleuri (Chaihu) has been used as a traditional medicine for more than 2000 years in China, Japan, Korea, and other Asian countries. Phytochemical studies demonstrated that this plant contains essential oils, triterpenoid saponins, polyacetylenes, flavonoids, lignans, fatty acids, and sterols. Crude extracts and pure compounds isolated from Radix Bupleuri exhibited various biological activities, such as anti-inflammatory, anticancer, antipyretic, antimicrobial, antiviral, hepatoprotective, neuroprotective, and immunomodulatory effects. However, Radix Bupleuri could also lead to hepatotoxicity, particularly in high doses and with long-term use. Pharmacokinetic studies have demonstrated that the major bioactive compounds (saikosaponins a, b₂, c, and d) were absorbed rapidly in rats after oral administration of the extract of Radix Bupleuri. This review aims to comprehensively summarize the traditional uses, botany, phytochemistry, pharmacology, toxicology, and pharmacokinetics of Radix Bupleuri reported to date with an emphasis on its biological properties and mechanisms of action.

Association of traditional Chinese medicine therapy and the risk of dementia in patients with hypertension: a nationwide population-based cohort study

BACKGROUND

Patients with hypertension (HTN) reportedly have a higher risk of developing dementia. However, it remains unclear if use of Traditional Chinese Medicine (TCM), the most common form of complementary and alternative medicine, can help lower the risk of dementia for these patients. So the aim of the study was to investigate the effects of TCM on dementia risk among patients with hypertension.

METHODS

This longitudinal cohort study used the Taiwanese National Health Insurance Research Database (NHIRD) to identify 143,382 newly diagnosed hypertension patients aged 20-90 years who received treatment between 1998 and 2007. Among them, 52,365 (36.52%) had received TCM after the onset of hypertension (TCM users), and the remaining 91,017 patients (63.48%) were designated as a control group (non-TCM users). All enrollees were followed until the end of 2012 to record the incidence of dementia. A Cox proportional hazards regression model was used to compute the hazard ratio (HR) of dementia in patients who received TCM.

RESULTS

During the 15-year follow-up, 3933 TCM users and 10,316 non-TCM users developed dementia, representing an incidence rate of 8.41 and 11.55%, respectively, per 1000 person-years. TCM users had a significantly reduced risk of dementia compared to non-TCM users (adjusted HR = 0.76; 95% confidence interval [CI] = 0.74-0.81). The predominant effect was observed among those treated with TCM longer than 180 days (adjusted HR = 0.65; 95% CI = 0.62-0.69). Among the commonly used TCM products, Tian-Ma-Gou-Teng-Yin, Dan-Shen (Radix Salviae Miltiorrhizae), Chuan-Niu-Xi (Radix Cyathulae), Ge-Gen (Radix Puerariae), Jia-Wei-Xiao-Yao-San, and Jue-Ming-Zi (Semen Cassiae) were significantly associated with a lower risk of dementia.

CONCLUSIONS

Results from this population-based study support the effects of TCM on reducing dementia risk, which may provide a reference for dementia prevention strategies.

Anti-Inflammation Effects and Potential Mechanism of Saikosaponins by Regulating Nicotinate and Nicotinamide Metabolism and Arachidonic Acid Metabolism

Inflammation is an important immune response; however, excessive inflammation causes severe tissue damages and secondary inflammatory injuries. The long-term and ongoing uses of routinely used drugs such as non-steroidal anti-inflammatory drugs (NSAIDS) are associated with serious adverse reactions, and not all patients have a well response to them. Consequently, therapeutic products with more safer and less adverse reaction are constantly being sought. Radix Bupleuri, a well-known traditional Chinese medicine (TCM), has been reported to have anti-inflammatory effects. However, saikosaponins (SS) as the main pharmacodynamic active ingredient, their pharmacological effects and action mechanism in anti-inflammation have not been reported frequently. This study aimed to explore the anti-inflammatory activity of SS and clarify the potential mechanism in acute inflammatory mice induced by subcutaneous injection of formalin in hind paws. Paw edema was detected as an index to evaluate the anti-inflammatory efficacy of SS. Then, a metabolomic method was used to investigate the changed metabolites and potential mechanism of SS. Metabolite profiling was performed by high-performance liquid chromatography combined with quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF-MS). The detection and identification of the changed metabolites were systematically analyzed by multivariate data and pathway analysis. As a result, 12 different potential biomarkers associated with SS in anti-inflammation were identified, including nicotinate, niacinamide, arachidonic acid (AA), and 20-carboxy-leukotriene B4, which are associated with nicotinate and nicotinamide metabolism and arachidonic acid metabolism. The expression levels of biomarkers were effectively modulated towards the normal range by SS. It indicated that SS show their effective anti-inflammatory effects through regulating nicotinate and nicotinamide metabolism and arachidonic acid metabolism.

Saikosaponin A Alleviates Symptoms of Attention Deficit Hyperactivity Disorder through Downregulation of DAT and Enhancing BDNF Expression in Spontaneous Hypertensive Rats

The disturbed dopamine availability and brain-derived neurotrophic factor (BDNF) expression are due in part to be associated with attention deficit hyperactivity disorder (ADHD). In this study, we investigated the therapeutical effect of saikosaponin a (SSa) isolated from Bupleurum Chinese DC, against spontaneously hypertensive rat (SHR) model of ADHD. Methylphenidate and SSa were orally administered for 3 weeks. Activity was assessed by open-field test and Morris water maze test. Dopamine (DA) and BDNF were determined in specific brain regions. The mRNA or protein expression of tyrosine hydroxylase (TH), dopamine transporter (DAT), and vesicles monoamine transporter (VMAT) was also studied. Both MPH and SSa reduced hyperactivity and improved the spatial learning memory deficit in SHRs. An increased DA concentration in the prefrontal cortex (PFC) and striatum was also observed after treating with the SSa. The increased DA concentration may partially be attributed to the decreased mRNA and protein expression of DAT in PFC while SSa exhibited no significant effects on the mRNA expression of TH and VMAT in PFC of SHRs. In addition, BDNF expression in SHRs was also increased after treating with SSa or MPH. The obtained result suggested that SSa may be a potential drug for treating ADHD.

Elucidation of the Anti-Inflammatory Mechanisms of Bupleuri and Scutellariae Radix Using System Pharmacological Analyses

Objective. This study was aimed at elucidating the molecular mechanisms underlying the anti-inflammatory effect of the combined application of Bupleuri Radix and Scutellariae Radix and explored the potential therapeutic efficacy of these two drugs on inflammation-related diseases. Methods. After searching the databases, we collected the active ingredients of Bupleuri Radix and Scutellariae Radix and calculated their oral bioavailability (OB) and drug-likeness (DL) based on the absorption-distribution-metabolism-elimination (ADME) model. In addition, we predicted the drug targets of the selected active components based on weighted ensemble similarity (WES) and used them to construct a drug-target network. Gene ontology (GO) analysis and KEGG mapper tools were performed on these predicted target genes. Results. We obtained 30 compounds from Bupleuri Radix and Scutellariae Radix of good quality as indicated by ADME assays, which possess potential pharmacological activity. These 30 ingredients have a total of 121 potential target genes, which are involved in 24 biological processes related to inflammation. Conclusions. Combined application of Bupleuri Radix and Scutellariae Radix was found not only to directly inhibit the synthesis and release of inflammatory cytokines, but also to have potential therapeutic effects against inflammation-induced pain. In addition, a combination therapy of these two drugs exhibited systemic treatment efficacy and provided a theoretical basis for the development of drugs against inflammatory diseases.