Research progress on modern pharmacological action of Radix bupleuri

LI Yue-yang, LEI Gen-ping, DONG Sheng, FENG Guan-qiang

1. Shaanxi University of Traditional Chinese Medicine, Xianyang 712046, China

2. Affiliated Hospital of Shaanxi University of Traditional Chinese Medicine, Xianyang 712000, China

Keywords:Bupleurum Saikosaponin Bupleurum polysaccharide Modern pharmacological action

ABSTRACT Radix bupleuri is the dried root of Umbelliferae plants Bupleurem chinense DC. or Bupleurem scorzonerifolium Willd., which are widely distributed in Northeast China, North China,Northwest China, East China, Hubei, Sichuan and other places. The plant roots are excavated in spring and autumn and dried with removing stems and leaves and sediment. Radix bupleuri,one of the oldest and most commonly used Chinese herbal medicine, has a long history of application, with high medicinal value. Modern pharmacological studies have shown that Radix bupleuri has pharmacological effects such as anti-cancer, anti-depression, anti-inflammation,heart protection, liver protection, and kidney protection, and mainly plays an role in regulating apoptosis signaling pathway, inflammation signaling pathway, neuroendocrine system,oxidative stress signaling pathway, and fibrosis signaling pathway. This paper reviews the modern pharmacological effects of Radix bupleuri in recent years, in order to provide reference for better research, development and rational utilization of Bupleurum resources.

1. Introduction

Bupleurum is the dry root of Bupleurem chinense DC. or Bupleurem scorzonerifolium Willd., Because of the differences in their traits, it is customary to call the former "North Bupleurum" and the latter"Southern Bupleurum".Bupleurum has been used in China for centuries and is one of the oldest and most commonly used Chinese herbal medicines.

Bupleurum was first published in the "Shennong herbal Scripture",and "Bupleurum has a bitter taste and has a mild nature. It is mainly used for gastrointestinal diseases, stagnated diet, and promotes metabolism. Long-term use can strengthen the body, improve eyesight, and replenish vital energy. Bupleurum is also known as ground smoke and grows in Chuangu." "Rihuazi Materia Medica"says: "Replenishing five fatigues and seven injuries, eliminating troubles and relieving convulsions, replenishing vital energy,eliminating phlegm, stopping cough, nourishing the heart and lungs,adding essence and nourishing marrow." "Medicinal Properties"also said: "The treatment of Kashin pain, shoulder and back pain,promote the circulation of Qi and blood." The 2020 Chinese Pharmacopoeia describes Bupleurum as "plenty, bitter, slightly cold.It returns to the liver, gallbladder, and lung meridians. It has the effects of relieving fever, soothing the liver and relieving depression,and lifting yang." Modern pharmacology shows that Bupleurum mainly contains saponins, polysaccharides, flavonoids and other chemical components. It has anti-cancer, anti-depression, antiinflammatory, heart protection, liver protection, kidney protection and other pharmacological effects[1-3].This article systematically collates research reports on Bupleurum at home and abroad in recent years, from the perspective of modern pharmacological effects, It is expected to provide a reference for the in-depth development and reasonable application of Bupleurum.

2. Pharmacological activities

Bupleurum has a variety of pharmacological activities, including anti-cancer, anti-depression, anti-inflammatory, heart protection,liver protection, kidney protection and other pharmacological effects.

2.1 Anti-cancer

Bupleurum can inhibit cell proliferation and induce cell apoptosis by regulating apoptosis signal pathway, activating inflammation signal pathway, influencing gene expression, regulating immunity and other dimensions, thereby exerting anti-cancer effect.

Saikosaponin A (SSA) reduces the proliferation and colony formation of triple negative breast cancer (TNBC) cells, inhibits the growth of tumors in situ, and blocks the migration and migration of TNBC cells to SDF-1α. Invasion and metastasis to the lungs also inhibited the expression of phosphorylated AKT, mTOR,MMP-2 and MMP-9 in TNBC. It shows that SSA can inhibit the proliferation, invasion and metastasis of TNBC cells by downregulating the expression of CXCR4 involved in PI3K/AKT/mTOR and MMP signaling pathways in TNBC cells, and can be used as a future therapeutic drug for TNBC[4].

Saikosaponin D (SSD) can significantly reduce the cell viability of pancreatic cancer cells, induce apoptosis, activate Caspase protein lysis, increase the expression of FoxO3a transcription factor in pancreatic cancer cells, and induce MKK4-in BxPC3 cells. Activation of the JNK signaling pathway. The results of this experiment prove that SSD inhibits the proliferation of pancreatic cancer cells and induces apoptosis by up-regulating the MKK4-JNK signaling pathway. It also shows that the MKK4-JNK pathway can be a potential target for the treatment of pancreatic cancer and can become a main candidate for the treatment of pancreatic cancer.Drugs [5].

Zhao X et al. [6] induced a rat model of breast cancer by gavage using dimethyl-benz anthracene (DMBA, 100 mg/kg). The experimental results showed that it was comparable to the control group, SSA significantly inhibits the growth and proliferation of tumor cells, regulates the immune cell infiltration of tumors, and promotes Th1/Th2 to increase the level of serum IFN-γ and IL-12 and decrease the level of serum IL-4 and IL-10. The transfer of Th1 increases the expression of IL-12, IL-12 receptor and phosphorylated STAT4. It is concluded that SSA can inhibit the growth of breast cancer cells by shifting the balance of Th1/Th2 to Th1. The underlying mechanism may be related to the activation of the IL-12/STAT4 pathway that induces Th1 differentiation.

SSD has an inhibitory effect on human non-small cell lung cancer(NSCLC) cell lines A549 and H1299. The higher the concentration of SSD, the stronger its inhibitory effect. The minimum inhibitory concentrations (IC50) for A549 and H1299 were 3.57 μM and 8.46 μM, respectively, and induced apoptosis of A549 and H1299 cells in a dose-dependent manner, reducing the number of cells, and also increasing G0/G1 in the two cell lines The cell ratio of the phase,the cell ratio is directly proportional to the concentration of SSD.It indicates that SSD may inhibit the proliferation of lung cancer cells by inhibiting the phosphorylation of STAT3 and activating Caspase-3, and induce cell cycle arrest and apoptosis [7].

Ren M et al. [8] found through experiments that SSD inhibited the proliferation of liver cancer cells in a dose-dependent manner.Among them, in the SSD (2.5-15 μg/mL) treatment group, cell apoptosis was significantly increased, pro-apoptotic proteins and anti-apoptotic proteins It increases and decreases simultaneously,and significantly reduces the translation and transcription levels of Cyclooxygenase-2 (COX-2), C/EBP β and p-STAT3. It can be concluded that SSD inhibits the expression of COX-2 by inhibiting the p-STAT3/C/EBP β signaling pathway to inhibit the proliferation of liver cancer cells and exert anti-cancer effects.

2.2 Anti-depression

《Medicine Huayi》says: "Taste is mild and bitter, which can dredge the liver Qi". The traditional Chinese medicine Bupleurum has the effects of soothing the liver and relieving depression and unblocking the liver qi. Modern pharmacology shows that Bupleurum can play an antidepressant effect by regulating the neuroendocrine system and improving inflammation signal pathways.

Su J et al. [9] used lipopolysaccharide (LPS, 0.83 mg/kg) to induce depression in male ICR mice, and conducted a behavioral test similar to depression. The results showed that SSD can inhibit LPS-induced hippocampal microglia activation and the release of inflammatory cytokines, inhibit LPS-induced HMGB1 expression and downstream TLR4/NF-κB signaling pathway, and block LPS-induced ectopic and release of HMGB1. It affects the TLR4/NF-κB signaling pathway in primary microglia, thereby effectively reversing the behaviors caused by LPS-induced mice in the tail suspension test (TST) and forced swimming test (FST) Desperate and improved the reduction of sucrose consumption in the sucrose preference test (SPT). It shows that SSD can effectively alleviate the inflammation-related depression behavior induced by LPS by improving the inflammatory signal pathway.

Chao B et al. [10] used unpredicted chronic mild stress (UCMS)to induce depression in male Sprague-Dawley rats, and performed SPT, FST, TST and open field test (OFT). The results showed that SSD increased the sucrose preference (SP) of rats in the SPT test,improved the spontaneous exploration ability of the rats in the OFT test, such as crossover ability, raising ability and grooming ability,and shortened the rats in the FST test. The immobility time and the rest time in the TST test significantly down-regulate the NF-κB signaling pathway. NF-κB negatively regulates the expression of Fibroblast growth factor 2 (FGF2) through transcriptional regulation of miR-155.The above results indicate that SSD can improve UCMS-induced depression behavior in rats through the NF-κB/miR-155/FGF2 axis.

Chen XQ et al. [11] selected female Wistar rats and also made UCMS rat depression models, and performed SPT test, FST test and novelty-suppressed feeding test (NSFT).The results showed that SSA increased the SP levels of rats in the SPT test, decreased the incubation period of rats in the NSFT test, reduced immobility 3 times in the FST test, and restored HPA axis imbalance and neuroinflammation in rats exposed to CUMS , Promote the BDNFTrkB signal transduction in the hippocampus, and reduce the levels of IL-1β, IL-6 and TNF-α in the hippocampus of rats. Through the above test results, it can be found that SSA exerts an antidepressant effect by improving neuroendocrine, neuroinflammation and neurotrophic system.

2.3 Anti-inflammatory

Bupleurum can effectively reduce the expression of proinflammatory cytokines and exert anti-inflammatory effects by inhibiting the NF-κB signaling pathway.

SSA significantly reversed the symptoms of interstitial edema,neutrophil infiltration and alveolar wall thickness in the LPSinduced acute lung injury (ALI) mouse model, and reduced myeloperoxidase(MPO) in a dose-dependent manner activity,reduce the wet weight/dry weight (W/D) ratio of the lungs,reduce the performance of pulmonary edema, reduce the levels of inflammatory cytokines TNF-α and IL-1β, and reduce NF-κB-Phosphorylation of P65 and IkBα, and reduces the expression of NLRP3, ASC and Caspase-1.The above results indicate that SSA inhibits the occurrence of inflammation by inhibiting the NF-κB and NLRP3 signaling pathways [12].

SSA dose-dependently attenuates the histopathological changes of dextran sulfate sodium (DSS)-induced male C57BL/6 mouse model of colitis, such as large-scale epithelial destruction, severe crypt destruction and inflammatory cell infiltration, Reduced body weight, colon length and disease activity index (DAI), also significantly reduced the level of MPO activity, reduced the levels of inflammatory cytokines TNF-α and IL-1β, and significantly reduced NF-κB activation and IkBα Phosphorylation and expression of LXRα in colon tissue. The above results indicate that SSA inhibits the inflammatory response by activating LXRα, thereby inhibiting the occurrence of DSS-induced colitis [13].

Piao CH et al. [14] selected male Balb/c male mice and used ovalbumin (OVA) to induce allergic rhinitis (AR) mouse models.The results showed that SSA decreased in a dose-dependent manner.The number of sneezing and nasal friction in mice improved the nasal symptoms, and significantly reduced the total number of cells,eosinophils, other inflammatory cells and exfoliated epithelial cells in nasal lavage fluid (NALF). Epithelial rupture and interstitial edema, and inhibit the infiltration of eosinophils and the proliferation of goblet cells and mast cells, significantly inhibit the production of OVA-specific IgE and IgG1, and reduce the levels of TNF-α,IL-5 and IL-13 , Reduce the levels of NF-κB, p-NF-κB, STAT3 and p-YSTAT3 in mouse NALF. The above test results show that SSA inhibits the IL-6/STAT3/RoR-γt and NF-κB pathways by regulating Th2 and Th17 cytokines, and has a significant inhibitory effect on the allergic inflammation of the nasal mucosa of the folliclestimulating AR mice.

Osteoarthritis is a degenerative joint disease. There are no clinically effective drugs. Inflammation and autophagy are the key factors for the occurrence and prognosis of osteoarthritis, PI3K/AKT/MTOR signaling pathway is an important autophagy modulator , SSD induces autophagy by inhibiting the PI3K/AKT/MTOR signaling pathway, which can alleviate the autophagy, inflammatory response and apoptosis of chondrocytes [15].

2.4 Heart protection

Bupleurum can protect the heart by inhibiting the activation of multiple signal pathways such as apoptosis signal pathway, oxidative stress response, and anti-inflammatory.

Rutin can significantly reduce the ratio of heart weight to body weight in the doxorubicin (Dox)-induced male C57BL/6J mouse cardiotoxicity model, improve left ventricular ejection fraction and left ventricular shortening fraction, and significantly reduce DOXinduced Cardiac fibrosis and the production of apoptotic cells in mouse heart tissue, reduce the expression of P62 and autophagy markers LC3II, ATG5, increase the expression of Bcl-2, reduce the level of Caspase-3 protein, and inhibit excessive in an AKTdependent manner Of autophagy and apoptosis to alleviate DOXinduced cardiac dysfunction, apoptosis and cardiomyocyte fibrosis[16].

Yang H et al. [17] established a hypoxia/reoxygenation injury H9c2 rat cardiomyocyte model, and found that rutin can increase the survival rate of H9c2 cardiomyocytes in the hypoxia/reoxygenation injury model H9c2 cardiomyocytes, and increase the SIRT1 in H9c2 cardiomyocytes. Expression, enhance cell viability and reduce myocardial damage. It shows that rutin can protect cardiomyocytes by regulating apoptosis signal pathway and oxidative stress response.In addition, isorhamnetin can significantly inhibit the increase in the size of myocardial cells in the presence of angiotensin II (Ang II) in cardiac remodeling model mice after mechanical overload. Decrease the levels of atrial natriuretic peptide(ANP), B-type brain natriuretic peptide(BNP) and β-myosin heavy chain(β-MHcmRNA) induced by Ang II. The above results indicate that isorhamnetin can reduce cardiac hypertrophy and cardiac fibrosis caused by pressure overload by inhibiting the PI3K-AKT signaling pathway, reduce the incidence of cardiac hypertrophy and heart failure, and can be a potential therapeutic drug [18].

Studies have found [19] that quercetin has significant related benefits to the heart. It mainly inhibits low-density lipoprotein (LDL)oxidation and non-endothelial-dependent vasodilation, and reduces adhesion molecules and other inflammatory markers. It has a protective effect on nitric oxide and endothelial function under stress conditions, prevents neuronal oxidation and inflammatory damage,as well as platelet anti-aggregation, and can be used as a potential therapeutic drug for cardiovascular diseases.

2.5 Liver protection

Bupleurum can protect the liver by inhibiting the production of proinflammatory molecules, resisting oxidative stress, and regulating protein expression.

Liu N et al. [20] prepared a mouse model of liver fibrosis by intraperitoneal injection of carbon tetrachloride (CCl4, 1 mL/kg)or bile duct ligation (BDL). The results showed that isorhamnetin decreased the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and hydroxyproline in a dose-dependent manner, and improved liver tissue inflammation infiltration and hepatocytes in mice. Swelling and necrosis, liver lobule damage,significantly reduce the expression of F4/80 mRNA in liver tissue,reduce the expression of liver tissue α-SMA, increase the expression of PPAR-γ, decrease the expression of TIMP1, and up-regulate the level of MMP-2 in mRNA and protein. Express, inhibit the activation of hepatic stellate cells (HSC), maintain the balance of extracellular matrix (ECM) production and degradation, and reduce the mRNA and protein levels of BECLIN-1 and LC3.From the above results, it can be seen that isorhamnetin inhibits the Smad3 and p38MAPK signaling pathways mediated by TGF-β1, thereby reducing autophagy and the formation of extracellular matrix. Plays the role of anti-liver fibrosis in mice, and also has a protective effect on chronic liver damage.

In addition, Zhu Y et al. [21] induced a mouse liver injury model by intraperitoneal injection of LPS (60 mg/kg) and d-galactosamine(D-GalN, 800 mg/kg),The experimental results showed that the liver tissue of the LPS/D-GalN group was severely damaged,with hepatocyte necrosis and a large number of inflammatory cell infiltration, while the above changes in the LPS/D-GalN+SSA group were lighter than those in the LPS/D-GalN group, the control group and the SSA group alone No pathological damage was seen in the liver tissue. SSA can significantly inhibit the levels of MPO and malondialdehyde (MDA) induced by LPS/D-GalN, and reduce the levels of AST and ALT in a dose-dependent manner, and inhibit LPS/D-GalN-induced TNF-α and IL The production of -1β inhibits the expression of NF-κB p65 and IkBα phosphorylation induced by LPS/D-GalN. From the above results, it can be found that SSA inhibits LPS/D-GalN-induced liver injury by activating LXRα, inhibiting the NF-κB signaling pathway and inflammatory response, indicating that SSA has a certain effect on the treatment of liver injury.

Chen Y et al. [22] selected male ICR mice and used CCl4to induce a mouse model of acute liver injury in mice, it was found through experiments that SSD reversed the increase in serum ALT, AST,and lactate dehydrogenase (LDH) levels in CCl4-induced acute liver injury in a dose-dependent manner, and significantly reduced MDA and mitochondrial superoxide production (MSP) levels. Increase the activity of superoxide dismutase (SOD), glutathione peroxidase(GPx) and catalase (CAT), reduce the expression of NLRP3, ASC and Caspase-1 induced by CCl4, and reduce the promotion of liver tissue The levels of inflammatory cytokines IL-1β and IL-18, also reduce the production of mitochondrial ROS. It is concluded that SSD can alleviate CCl4-induced hepatitis acute liver injury by inhibiting oxidative stress and NLRP3 inflammasome activation.

2.6 Kidney protection

Bupleurum can protect the kidneys by inhibiting inflammatory signal pathways, oxidative stress and fibrosis, and may become a potential therapeutic drug for kidney diseases.

Al-Harbi NO et al. [23] induced Wistar albino rat nephrotoxicity model by intraperitoneal injection of carfilzomib (CFZ, 4 mg/kg),The results showed that rutin significantly reversed the decrease of red blood cell (RBC), white blood cell (WBC), hemoglobin (HB),hematocrit percentage (Hct%), and mean red blood cell volume(MCV) caused by CFZ in a dose-dependent manner (P＜0.05), and significantly prevented iNOS and IL-17 protein expression, inhibited CFZ-induced NF-κB p65 activation and increased phosphorylated IkB-α protein expression, and reduced direct bilirubin (DBIL), serum creatinine (SCr) and blood urea nitrogen (BUN) level, improves total protein (TP) and serum uric acid (SUA) levels. Rutin significantly reduced MDA levels and CAT activity, increased reduced glutathione(GSH) levels and glutathione reductase (GR) activity, reduced Caspase-3 enzyme activity, and improved the CFZ-induced rat Dilation, flatness, necrosis, and degeneration of the renal tubular structure. This experiment shows that rutin protects the kidneys from CFZ-induced nephrotoxicity through anti-oxidative stress and antiinflammatory effects, and at the same time reduces cell apoptosis in the kidneys.

Furthermore, Liu ZZ et al. [24] selected male C57BL/6 mice and used streptozotozin (STZ, 100 mg/kg) to induce a diabetic mouse model.Compared with the model group, Bupleurum polysaccharides significantly reduced blood sugar in STZ-induced diabetic mice,reduced kidney swelling, reduced SCr, urinary albumin excretion rate (UAER) and β-2-MG levels, and improved glomerular hypertrophy and atrophy. Mesangial matrix thickening, partial renal tubular vacuolation, partial glomerulus and renal tubular interstitial mild fibrosis and other renal pathological changes,reduce renal tissue extracellular matrix protein type IV collagen(Col IV), fibrosis Protein (Fn) and α-smooth muscle actin (α-SMA)expression, Significantly reduce the levels of TNF-α and IL-6 in kidney tissue homogenate, reduce the expression of TLR4 in kidney tissue, inhibit the overexpression and release of HMGB1, and significantly reduce the levels of HMGB1 and p-NF-κB p65.The above experimental results prove that Bupleurum polysaccharide can improve the inhibition of HMGB1-TLR4 signaling pathway, reduce the inflammatory response and fibrosis process in the kidney tissue of diabetic mice, and play a role in protecting the kidney.

2.7 Other pharmacological effects

Bupleurum also has anti-Alzheimer's disease, anti-aging and anti-obesity effects. The main active ingredient of Bupleurum against Alzheimer’s disease is saikosaponin, Saikosaponins play an anti-Alzheimer's effect mainly by regulating the production of neurotransmitters, regulating cell apoptosis pathways, and inhibiting protein deposition [25,26].The anti-aging effects of Bupleurum polysaccharides are mainly related to regulating the cell cycle, reducing oxidative stress, and inhibiting the expression of inflammatory cytokines [27, 28].The anti-obesity effect of saikosaponin is related to the activation of 5-HT2C receptors, which can inhibit appetite and weight gain [29].

3. Clinical application

Bupleurum is mostly in the form of compound prescriptions in clinical practice, it mainly includes Xiaochaihu Decoction, Dachaihu Decoction, Xiaoyao Powder, Chaihu Shugan Powder, etc. with Bupleurum as the "prince medicine". Clinical studies have shown that Chaihu compound, modified and combined Western medicines are widely used in depression, pneumonia, gastritis, thyroiditis,diabetes, hypertension, fatty liver, pancreatic cancer and other diseases (Table 1).

Tab 1 Clinical application of Bupleurum compound

4. Conclusion and prospect

Bupleurum has a long history of medicinal use and is one of the commonly used Chinese medicines in my country. It has the functions of relieving fever, soothing liver and relieving depression,and lifting yang qi. In recent years, scientific research on Bupleurum has gradually increased. Studies have shown that Bupleurum contains a variety of chemical components, including but not limited to: saponins, flavonoids, polysaccharides, volatile oil, etc.In summary, we can find that Bupleurum has anti-cancer, antidepression, anti-inflammation, heart protection. Its pharmacological effects are mainly realized by regulating apoptosis signal pathway,inflammation signal pathway, neuroendocrine system, oxidative stress signal pathway, fibrosis signal pathway and so on. Liver protection, kidney protection, etc. At present, although the research on the pharmacological effects of Bupleurum has achieved considerable results, the specific mechanism of the pharmacological effects of the chemical components of Bupleurum is still unclear, and the research on which pharmacological effects of the various main active ingredients correspond is not deep enough. It is necessary to combine molecular biology, metabolomics and other related knowledge to deeply explore the pharmacological mechanism of action and metabolic laws to provide a theoretical basis for its product development.

Author's contribution:

Li Yue-yang: Author of the article; Lei Gen-ping: Provide ideas and direction; Dong Sheng: Check the full text and modify it; Feng Guan-qiang: modify.

All authors declare no conflict of interest.