Effects of 2,3,4',5-tetrahydroxystilbene 2-O-beta-D-glucoside on vascular endothelial dysfunction in atherogenic-diet rats

A comprehensive review of traditional uses, phytochemistry and pharmacology of Reynoutria genus

Objectives

The genus Reynoutria belonging to the family Polygonaceae is widely distributed in the north temperate zone and used in folk medicine. It is administered as a sedative, tonic and digestive, also as a treatment for canities and alopecia. Herein, we reported a review on traditional uses, phytochemistry and pharmacology reported from 1985 up to early 2022. All the information and studies concerning Reynoutria plants were summarized from the library and digital databases (e.g. ScienceDirect, SciFinder, Medline PubMed, Google Scholar, and CNKI).

Key findings

A total of 185 articles on the genus Reynoutria have been collected. The phytochemical investigations of Reynoutria species revealed the presence of more than 277 chemical components, including stilbenoids, quinones, flavonoids, phenylpropanoids, phospholipids, lactones, phenolics and phenolic acids. Moreover, the compounds isolated from the genus Reynoutria possess a wide spectrum of pharmacology such as anti-atherosclerosis, anti-inflammatory, antioxidative, anticancer, neuroprotective, anti-virus and heart protection.

Summary

In this paper, the traditional uses, phytochemistry and pharmacology of genus Reynoutria were reviewed. As a source of traditional folk medicine, the Reynoutria genus have high medicinal value and they are widely used in medicine. Therefore, we hope our review can help genus Reynoutria get better development and utilization.

A Review of Pharmacology, Toxicity and Pharmacokinetics of 2,3,5,4'-Tetrahydroxystilbene-2-O-β-D-Glucoside

Polygonum multiflorum Thunb. (He-shou-wu in Chinese), a Chinese botanical drug with a long history, is widely used to treat a variety of chronic diseases in clinic, and has been given the reputation of “rejuvenating and prolonging life” in many places. 2,3,4′,5-tetrahydroxystilbene-2-O-β-D-glucoside (TSG, C₂₀H₂₂O₉) is the main and unique active ingredient isolated from Polygonum multiflorum Thunb., which has extensive pharmacological activities. Modern pharmacological studies have confirmed that TSG exhibits significant activities in treating various diseases, including inflammatory diseases, neurodegenerative diseases, cardiovascular diseases, hepatic steatosis, osteoporosis, depression and diabetic nephropathy. Therefore, this review comprehensively summarizes the pharmacological and pharmacokinetic properties of TSG up to 2021 by searching the databases of Web of Science, PubMed, ScienceDirect and CNKI. According to the data, TSG shows remarkable anti-inflammation, antioxidation, neuroprotection, cardiovascular protection, hepatoprotection, anti-osteoporosis, enhancement of memory and anti-aging activities through regulating multiple molecular mechanisms, such as NF-κB, AMPK, PI3K-AKT, JNK, ROS-NO, Bcl-2/Bax/Caspase-3, ERK1/2, TGF-β/Smad, Nrf2, eNOS/NO and SIRT1. In addition, the toxicity and pharmacokinetics of TSG are also discussed in this review, which provided direction and basis for the further development and clinical application of TSG.

The Protective Effect of Tetrahydroxystilbene Glucoside on High Glucose-Induced Injury in Human Umbilical Vein Endothelial Cells through the PI3K/Akt/eNOS Pathway and Regulation of Bcl-2/Bax

Endothelial dysfunction plays a central role in the patho-genesis of diabetic vascular complications. 2,3,5,4'-tetra-hydroxystilbene-2-O-β-D-glucoside (TSG), an active component extracted from the roots of Polygonum multiflorum Thunb, has been shown to have strong antioxidant and antiapoptotic activities. In the present study, we investigated the protective effect of TSG on apoptosis induced by high glucose in human umbilical vein endothelial cells (HUVECs) and the possible mechanisms. Our data demonstrated that TSG significantly reversed the high glucose-induced decrease in cell viability, suppressed high glucose-induced generation of intracellular reactive oxygen species (ROS), the activity of caspase-3, and decreased the percentage of apoptotic cells in a dose-dependent manner. In addition, we found that TSG not only increased the expression of Bcl-2, while decreasing Bax expression, but also activated phosphorylation of Akt and endothelial nitric oxide synthase (eNOS) with subsequent nitric oxide production and ultimately reduced high glucose-induced apoptosis. However, the antiapoptotic effects of TSG were abrogated by pretreatment of the cells with PI3K inhibitor (LY294002) or eNOS inhibitor NG-L-nitro-arginine methyl ester, respectively. These results suggest that TSG inhibits high glucose-induced apoptosis in HUVECs through inhibition of ROS production, activation of the PI3K/Akt/eNOS pathway, and upregulation of the Bcl-2/Bax ratio, and thus may demonstrate significant potential for preventing diabetic cardiovascular complications.

SIRT1 Is the Target Gene for 2,3,5,4'-Tetrahydroxystilbene-2-O-β-D-Glucoside Alleviating the HUVEC Senescence

This study aimed to explore the effects of 2,3,5,4'-tetrahydroxy-stilbene-2-O-β-d-glucoside (TSG) on the senescence of human umbilical vein cells (HUVEC) induced by hydrogen peroxide (H₂O₂) and to identify the potential targets mediating its protective action. HUVEC cells pre-treated with TSG for 24 h were exposed to H₂O₂ treatment. TSG significantly decreased H₂O₂-induced cellular senescence, as indicated by reduced senescence-associated β-galactosidase (SA-β-gal) positive staining, the proportion of cells in the G1 phase, cell apoptosis, p21, and plasminogen activator inhibitor-1 (PAI-1) expression. Moreover, TSG promoted Sirtuin 1 (SIRT1) expression. When SIRT1 was inhibited by EX527 or SIRT1 siRNA, the effect of TSG is diminished according to the increased proportion of cells in the G1 phase, cell apoptosis, p21, and PAI-1 expression. Overall, our study established TSG as an anti-senescence compound that exerts its protective action by regulating SIRT1 expression.

Biological Effects of Tetrahydroxystilbene Glucoside: An Active Component of a Rhizome Extracted from Polygonum multiflorum

Polygonum multiflorum Thunb. (PM), a traditional Chinese medicinal herb, has been widely used in the Orient as a tonic and antiaging agent. 2,3,5,4'-Tetrahydroxystilbene-2-O-β-D-glucoside (TSG, C20H22O9, FW = 406.38928) is one of the active components extracted from PM. TSG is an antioxidant agent, which exhibits remarkable antioxidative activities in vivo and in vitro. The antioxidant effect of TSG is achieved by its radical-scavenging effects. TSG can inhibit apoptosis and protect neuronal cells against injury through multifunctional cytoprotective pathways. TSG performs prophylactic and therapeutic activities against Alzheimer's disease, Parkinson's disease, and cerebral ischemia/reperfusion injury. It is also antiatherosclerotic and anti-inflammatory. However, the mechanisms underlying these pharmacological activities are unclear. This study aimed at reviewing experimental studies and describing the effectiveness and possible mechanisms of TSG.

Protective Effects of 2,3,5,4'-Tetrahydroxystilbene-2-O-β-d-glucoside on Ovariectomy Induced Osteoporosis Mouse Model

2,3,5,4'-Tetrahydroxystilbene-2-O-β-d-glucoside (TSG), an active polyphenolic component of Polygonum multiflorum, exhibits many pharmacological activities including antioxidant, anti-inflammation, and anti-aging effects. A previous study demonstrated that TSG protected MC3T3-E1 cells from hydrogen peroxide (H₂O₂) induced cell damage and the inhibition of osteoblastic differentiation. However, no studies have investigated the prevention of ovariectomy-induced bone loss in mice. Therefore, we investigated the effects of TSG on bone loss in ovariectomized mice (OVX). Treatment with TSG (1 and 3 μg/g; i.p.) for six weeks positively affected body weight, uterine weight, organ weight, bone length, and weight change because of estrogen deficiency. The levels of the serum biochemical markers of calcium (Ca), inorganic phosphorus (IP), alkaline phosphatase (ALP), and total cholesterol (TCHO) decreased in the TSG-treated mice when compared with the OVX mice. Additionally, the serum bone alkaline phosphatase (BALP) levels in the TSG-treated OVX mice were significantly increased compared with the OVX mice, while the tartrate-resistant acid phosphatase (TRAP) activity was significantly reduced. Furthermore, the OVX mice treated with TSG showed a significantly reduced bone loss compared to the untreated OVX mice upon micro-computed tomography (CT) analysis. Consequently, bone destruction in osteoporotic mice as a result of ovariectomy was inhibited by the administration of TSG. These findings indicate that TSG effectively prevents bone loss in OVX mice; therefore, it can be considered as a potential therapeutic for the treatment of postmenopausal osteoporosis.

2,3,4′,5-tetrahydroxystilbene-2-O-β-d-glycoside attenuates atherosclerosis in apolipoprotein E-deficient mice: role of reverse cholesterol transport

The aim of this study was to evaluate the potential effects of 2,3,4′,5-tetrahydroxystilbene-2-O-β-d-glucoside (TSG) on the development of atherosclerotic plaque in ApoE−/− mice, and explore the mechanisms involved. Our data showed that after 8 weeks of treatment, TSG ameliorated serum levels of total cholesterol, triglyceride, and low density lipoprotein cholesterol, and increased serum levels of high density lipoprotein cholesterol in ApoE−/− mice. TSG suppressed hepatic steatosis, the formation of atherosclerotic lesions, and the formation of macrophage foam cells in ApoE−/− mice. Moreover, TSG improved the expressions of hepatic SR-BI, ABCG5, and CYP7A1, and up-regulated the protein expressions of aortic ABCA1 and ABCG1. An in-vitro study showed that TSG promoted macrophage cholesterol efflux and increased the protein expressions of ABCA1 and ABCG1. Our findings provide evidence for a positive role of TSG in preventing atherosclerosis by promoting reverse cholesterol transport. These effects may be achieved by stimulating cholesterol efflux through ABCA1 and ABCG1, promoting SR-BI-mediated cholesterol uptake in the liver, increasing secretion of cholesterol into bile by ABCG5, and improving cholesterol metabolism by the CYP7A1 pathway. In addition, antioxidative and anti-inflammatory effects of TSG may also contribute to its inhibitory effects on atherosclerosis. Further study is needed to investigate whether other potential mechanisms are involved in TSG-mediated atheroprotection.

Tetrahydroxystilbene glucoside isolated from Polygonum multiflorum Thunb. demonstrates osteoblast differentiation promoting activity

Polygonum multiflorum Thunb. is a traditional Chinese medicinal herb that has been widely used to treat age-associated diseases. Tetrahydroxystilbene glucoside (TSG), also known as 2,3,5,4-tetrahydroxystilbene-2-O-β-D-glucoside, is a major component of this herb. The present study was designed to investigate the osteogenic differentiation promoting activity of TSG in rat mesenchymal stem cells (MSCs) and in zebrafish. Preliminary experiments using MTT assay and ALP methods indicate that the high potential activity for promoting osteogenic differentiation was observed when 50% ethanol eluate was used. Further isolation and purification of TSG from the 50% ethanol eluate was performed by bioassay-guided fractionation, and its structure was confirmed using nuclear magnetic resonance and mass spectrometry analyses. In addition, the relative content of TSG with the highest potential activity in the promotion of osteogenic differentiation was identified as 14.34% by reversed-phase high performance liquid chromatography. Subsequently, the osteogenic differentiation promoting abilities of TSG in MSCs were examined. The results demonstrated that TSG promoted the alkaline phosphatase activity at concentrations of 1.56–25 µg/ml, while it increased the content of osteocalcin 7 days after treatment with 6.25–25 µg/ml in MSCs. Furthermore, experiments in zebrafish indicated that different concentrations of TSG (3.12–12.5 µg/ml) protected against further bone loss induced by 10 µmol/l dexamethasone (Dex), simulating an osteoporosis (OP) model. TSG treatment (12.5 µg/ml) in Dex-induced zebrafish significantly increased the area of nodules by 50.14% compared with the untreated model group. In conclusion, TSG, as a major component of P. multiflorum Thunb. exhibited an osteogenic promoting activity in MSCs and in zebrafish. The results provided scientific evidence to support the potential use of TSG for protecting the bone in degenerative diseases, such as OP.

Current pharmacological developments in 2,3,4',5-tetrahydroxystilbene 2-O-β-D-glucoside (TSG)

2,3,4',5-tetrahydroxystilbene 2-O-β-D-glucoside (TSG), a resveratrol analog with glucoside, is purified from a traditional Chinese herbal medicine polygonum multiflorum. It has been extensively studied in last decade and known to exert strong anti-inflammatory, anti-oxidative, anti-apoptotic, and free radical scavenging activities, and therefore has been listed as a potential agent for disease therapies. Recent studies extend well-beyond effects of TSG on the injury of neurons, cardiomyocytes and endothelial cells, and report important functions of TSG in a lot of pathophysiological conditions. For example, TSG has been shown to prevent the production of pro-inflammatory cytokines in microglia and macrophages in vitro, and ameliorate pro-inflammatory responses in animal models with neurodegeneration, atherosclerosis, and rat paw or ear oedema. TSG can prevent the proliferation of vascular smooth cells, gastrointestinal dysfunctions, platelet aggregation, osteoblastic injury, diabetic nephropathy and melanogenesis. TSG is also indicated to facilitate long-term potentiation and learning and memory in both normal and pathological conditions. These effects to some extent enrich the understanding about the role of TSG in disease prevention and therapy. However, to date, we still have no outlined knowledges about the pharmacological effects of TSG, though the role of TSG in aging and Alzheimer's disease has been reviewed in recent years. Here, we summarize the current pharmacological developments of TSG as well as its possible mechanisms in disease prevention and therapy, aiming to push the understanding about the protective role of TSG as well as its preclinical assessment of novel applications.

Tetrahydroxystilbene Glucoside Inhibits Excessive Autophagy and Improves Microvascular Endothelial Dysfunction in Prehypertensive Spontaneously Hypertensive Rats

Autophagy exists in vascular endothelial cells, but the relationship between autophagy and blood vessel dysfunction in hypertension remains elusive. This study aimed to investigate role of autophagy in vascular endothelial dysfunction in prehypertension and hypertension and the underlying mechanisms involved. Furthermore, we sought to determine if and how tetrahydroxystilbene glucoside (TSG), a resveratrol analogue and active ingredient of Polygonum multiflorum Thunb used for its cardiovascular protective properties in traditional Chinese medicine, influences vascular endothelial function. Male spontaneously hypertensive rats (SHRs) aged 4 weeks (young) and 12 weeks (adult) were studied and the vascular function of isolated aorta and mesenteric artery was assessed in vitro. Compared with Wistar Kyoto rats (WKY), young and adult SHRs showed endothelial dysfunction of the aorta and mesenteric artery, along with decreased pAkt, pmTOR, and autophagic marker protein p62 and increased LC3 II/I in microvascular but not aortic tissues. TSG administration for 14 days significantly improved mesenteric vascular endothelial function, increased levels of pAkt and pmTOR, and decreased autophagy. Pretreatment of young SHRs with the mTOR inhibitor rapamycin blocked the antiautophagic and vasodilative effects of TSG. Moreover, TSG significantly activated Akt-mTOR signaling in HUVECs and reduced the autophagic levels in vitro, which were almost completely blocked by rapamycin. In summary, mesenteric endothelial dysfunction in prehypertensive SHRs was at least partly attributable to excessive autophagy in vascular tissues. TSG partly restored microvascular endothelial dysfunction through activating the Akt/mTOR pathway, which consequently suppressed autophagy, indicating that TSG could be potentially applied to protect vascular function against subclinical changes in prehypertension.

Biological Activities of 2,3,5,4'-Tetrahydroxystilbene-2-O-β-D-Glucoside in Antiaging and Antiaging-Related Disease Treatments

2,3,5,4′-Tetrahydroxystilbene-2-O-β-D-glucoside (THSG) is active component of the Chinese medicinal plant Polygonum multiflorum Thunb. (THSG). Pharmacological studies have demonstrated that THSG exhibits numerous biological functions in treating atherosclerosis, lipid metabolism, vascular and cardiac remodeling, vascular fibrosis, cardiac-cerebral ischemia, learning and memory disorders, neuroinflammation, Alzheimer and Parkinson diseases, diabetic complications, hair growth problems, and numerous other conditions. This review focuses on the biological effects of THSG in antiaging and antiaging-related disease treatments and discusses its molecular mechanisms.

Aortic Remodelling Is Improved by 2,3,5,4'-Tetrahydroxystilbene-2-O-β-D-glucoside Involving the Smad3 Pathway in Spontaneously Hypertensive Rats

Hypertension is a common health problem that substantially increases the risk of cardiovascular disease. The condition increases blood pressure, which causes alterations in vascular structure and leads to the development of vascular pathologies. 2,3,5,4′-Tetrahydroxystilbene-2-O-β-D-glucoside (THSG), a resveratrol analogue extracted from a Chinese medicinal plant, has been proven to have numerous vascular protection functions. This study investigated whether THSG can improve vascular remodeling, which has thus far remained unclear. Orally administering THSG to spontaneously hypertensive rats (SHRs) aged 12 weeks for 14 weeks significantly inhibited intima-media thickness in the lower parts of the aortic arch, increased the vascular diastolic rate in response to acetylcholine, and reduced remodelling-related mRNA expression, such as that of ACTA2, CCL3, COL1A2, COL3A1, TIMP1 WISP2, IGFBP1, ECE1, KLF5, MYL1 BMP4, FN1, and PAI-1. Immunofluorescence staining also showed an inhibitory effect similar to that of THSG on PAI-1 protein expression in rat aortas. Results from immunoprecipitation and a Western blot assay showed that THSG inhibited the acetylation of Smad3. A chromatin immunoprecipitation assay showed that THSG prevented Smad3 binding to the PAI-1 proximal promoter in SHR aortas. In conclusion, our results demonstrated that the inhibitory effect of THSG on aortic remodelling involved the deacetylating role of Smad3 with increasing blood flow and with constant blood pressure.

Tetrahydroxystilbene glucoside inhibits TNF-α-induced migration of vascular smooth muscle cells via suppression of vimentin

Vascular smooth muscle cell (VSMC) migration triggered by TNF-α is an important event that occurs during the development of atherosclerosis. 2,3,5,4'-Tetrahydroxystilbene-2-O-β-d-glucoside (TSG) has been proven to exhibit significant anti-atherosclerotic activity. Herein we investigate the inhibitory effect of TSG on TNF-α-induced VSMC migration and explore the underlying mechanisms. TSG pretreatment markedly inhibited TNF-α-induced cell migration. The inhibition of vimentin redistribution and expression was involved in the inhibitory effect of TSG on VSMC migration. The suppression of vimentin expression by shRNA in VSMCs significantly inhibited TNF-α-induced cell migration. Furthermore, TSG inhibited the TNF-α-induced expression of TGFβ1 and TGFβR1, and phosphorylation of TGFβR1 and Smad2/3. TSG also suppressed the nuclear translocation of Smad4 induced by TNF-α. These results suggest that TSG inhibits VSMC migration induced by TNF-α through inhibiting vimentin rearrangement and expression. The interruption of TGFβ/Smad pathway appears to be responsible for the suppression of TSG on vimentin expression.

Tetrahydroxystilbene Glucoside Improves TNF-α-Induced Endothelial Dysfunction: Involvement of TGFβ/Smad Pathway and Inhibition of Vimentin Expression

Endothelial dysfunction plays an important role in the pathogenesis of atherogenesis. 2,3,5,4′-tetrahydroxystilbene-2-O-β-D-glucoside (TSG), an active component of the rhizome extract from Polygonum multiflorum (PM), exhibits significant anti-atherosclerotic activity. Here, we used human umbilical vein endothelial cells (HUVECs) induced by tumor necrosis factor-α (TNF-α) in vitro to investigate the cytoprotective effects of TSG on TNF-α-induced endothelial injury and the related mechanisms. Pretreatment with 50 and 100 μM TSG markedly attenuated TNF-α-induced loss of cell viability and release of lactate dehydrogenase (LDH) and inhibited TNF-α-induced cell apoptosis. The inhibition of vimentin expression was involved in the cytoprotection afforded by TSG. Using inhibitors for PI3K and TGFβ or siRNA for Akt and Smad2, we found that vimentin production in HUVECs is regulated by TGFβ/Smad signaling, but not by PI3K–Akt–mTOR signaling. Meanwhile, TSG inhibited both the expression of TGFβ1 and the phosphorylation of Smad2 and Smad3, and TSG suppressed the nuclear translocation of Smad4 induced by TNF-α. These results suggest that TSG protects HUVECs against TNF-α-induced cell damage by inhibiting vimentin expression via the interruption of the TGFβ/Smad signaling pathway.

Activation of mitochondrial function and Hb expression in non-haematopoietic cells by an EPO inducer ameliorates ischaemic diseases in mice

BACKGROUND AND PURPOSE

Many organs suffer from ischaemic injuries that reduce their ability to generate sufficient energy, which is required for functional maintenance and repair. Erythropoietin (EPO) ameliorates ischaemic injuries by pleiotropic effects. The aim of this study was to investigate the effect and mechanism of a small molecule EH-201, and found it as a potent EPO inducer and its effect in non-haematopoietic cells for therapeutic potential in ischemic disorders.

EXPERIMENTAL APPROACH

Mice kidney slices, primary hepatocytes, primary cardiomyocytes and C2C12 myoblasts were treated with EH-201. The effects of this treatment on EPO, Hb expression and mitochondrial biogenesis were analysed. In vivo, doxorubicin-induced cardiomyopathic mice were treated with EH-201. The mice were subjected to an endurance test, electrocardiography and echocardiography, and a histological examination of the isolated hearts was performed. EH-201 was also administered to cisplatin-induced nephropathic mice.

KEY RESULTS

In non-haematopoietic cells, EH-201 was potent at inducing EPO. EH-201 also stimulated mitochondrial biogenesis and enhanced the expression of Hb by a mechanism dependent on EPO-mediated signalling. In mechanistic studies, using EPO and EPO receptor-neutralizing antibodies, we confirmed that EH-201 enhances EPO-EPOR autocrine activity. EH-201 robustly increased the endurance performance activity of healthy and cardiomyopathic mice during hypoxic stress, enhanced myocardial mitochondrial biogenesis and Hb expression, and also improved cardiac function. EH-201 ameliorated anaemia and renal dysfunction in nephropathic mice.

CONCLUSIONS AND IMPLICATIONS

The enhancement and recovery of cellular functions through the stimulation of mitochondrial activity and Hb production in non-haematopoietic cells by an inducer of endogenous EPO has potential as a therapeutic strategy for ischaemic diseases.

Inhibitory effects of 2,3,4',5-tetrahydroxystilbene-2-O-β-D-glucoside on angiotensin II-induced proliferation of vascular smooth muscle cells

OBJECTIVE

To investigate the effect of 2,3,4',5-tetrahydroxystilbene-2-O-β-D-glucoside (TSG), an active component extracted from the root of Polygonum multiflorum, on angiotensin II (Ang II)-induced proliferation of cultured rat vascular smooth muscle cells (VSMCs) and to identify the potential mechanism.

METHODS

Cell proliferation and cell cycle were determined by cell counting, 5-bromo-2'-deoxyuridine incorporation assay, proliferating cell nuclear antigen protein expression and flow cytometry. Levels of phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2), mitogenic extracellular kinase 1/2 (MEK1/2) and Src in VSMCs were measured by Western blot. The expression of c-fos, c-jun and c-myc mRNA were measured by reverse transcription polymerase chain reaction (RT-PCR). Intracellular reactive oxygen species (ROS) was measured by fluorescence assay.

RESULTS

TSG significantly inhibited Ang II-induced VSMCs proliferation and arrested cells in the G /S checkpoint (P<0.05 or P<0.01). TSG decreased the levels of phosphorylated ERK1/2, MEK1/2 and Src in VSMCs (P<0.05 or P<0.01). TSG also suppressed c-fos, c-jun and c-myc mRNA expression <0.05 or P<0.01). In addition, the intracellular ROS was reduced by TSG (P<0.01).

CONCLUSIONS

TSG inhibited Ang II-induced VSMCs proliferation. Its antiproliferative effect might be associated with down-regulation of intracellular ROS, followed by the suppression of the Src-MEK1/2-ERK1/2 signal pathway, and hence, blocking cell cycle progression.

Hexane extracts of Polygonum multiflorum improve tissue and functional outcome following focal cerebral ischemia in mice

Polygonum multiflorum is a traditional Korean medicine that has been utilized widely in East Asian countries as a longevity agent. Clinical studies have demonstrated that Polygonum multiflorum improves hypercholesterolemia, coronary heart disease, neurosis and other diseases commonly associated with aging. However, scientific evidence defining the protective effects and mechanisms of Polygonum multiflorum against ischemic stroke is incomplete. In the present study, we investigated the cerebrovascular protective effects of Polygonum multiflorum against ischemic brain injury using an in vivo photothrombotic mouse model. To examine the underlying mechanism of action, we utilized an in vitro human brain microvascular endothelial cell (HBMEC) culture system. Hexane extracts (HEPM), ethyl acetate extracts (EAEPM) and methanol extracts (MEPM) of Polygonum multiflorum (100 mg/kg) were administered intraperitoneally 30 min prior to ischemic insult. Focal cerebral ischemia was induced in C57BL/6J mice and endothelial nitric oxide synthase knockout (eNOS KO) mice by photothrombotic cortical occlusion. We evaluated the infarct volume, as well as neurological and motor function, 24 h after ischemic brain injury. Following ischemic insult, HEPM induced a significant reduction in infarct volume and subsequent neurological deficits, compared with EAEPM and MEPM. HEPM significantly decreased infarct size and improved neurological and motor function, which was not observed in eNOS KO mice, suggesting that this cerebroprotective effect is primarily an eNOS-dependent mechanism. In vitro, HEPM effectively promoted NO production, however these effects were inhibited by the NOS inhibitor, L-NAME and the PI3K/Akt inhibitor, LY-294002. Furthermore, HEPM treatment resulted in increased phosphorylation-dependent activation of Akt and eNOS in HBMEC, suggesting that HEPM increased NO production via phosphorylation-dependent activation of Akt and eNOS. In conclusion, HEPM prevents cerebral ischemic damage through an eNOS-dependent mechanism, and thus may have clinical applications as a protective agent against neurological injury in stroke.

TSG (2,3,4' ,5-tetrahydroxystilbene 2-O-β-D-glucoside) suppresses induction of pro-inflammatory factors by attenuating the binding activity of nuclear factor-κB in microglia

BACKGROUND

Induction of pro-inflammatory factors is one of the characteristics of microglia activation and can be regulated by numerous active components of Chinese traditional herbs. Suppression of pro-inflammatory factors is beneficial to alleviate microglia-mediated cell injury. The present study aims to investigate the effect and possible mechanism of 2,3,4',5-tetrahydroxystilbene 2-O-β-D-glucoside (TSG) on LPS-mediated induction of pro-inflammatory factors in microglia.

METHODS

Western blot, ELISA, and Hoechst 33258 were used to measure the protein expression, TNF-α/IL-6 content, and apoptotic nuclei, respectively. The mRNA level was measured by real time-PCR. Nitric oxide (NO) content, lactate dehydrogenase (LDH) content, and NF-κB binding activity were assayed by commercial kits.

RESULTS

TSG reduced iNOS protein expression as well as TNF-α, IL-6, and NO content in LPS-stimulated BV-2 cells. TSG attenuated the increase in apoptotic nuclei, caspase-3 cleavage, and LDH content induced by BV-2 cell-derived conditioned medium in primary hippocampal neurons. Mechanistic studies showed that TSG reduced the mRNA level of iNOS, TNF-α, and IL-6. TSG failed to suppress IκB-α degradation, NF-κB phosphorylation and nuclear translocation, and ERK1/2, JNK, and p38 phosphorylation. TSG, however, markedly reduced the binding of NF-κB to its DNA element. Chromatin immunoprecipitation (ChIP) assays confirmed that TSG reduced NF-κB binding to the iNOS promoter. These findings were ascertained in primary microglia where the LPS-induced increase in iNOS expression, NO content, apoptotic nuclei, and NF-κB binding to its DNA element were diminished by TSG.

CONCLUSIONS

These studies demonstrate that TSG attenuates LPS-mediated induction of pro-inflammatory factors in microglia through reducing the binding activity of NF-κB. This might help us to further understand the pharmacological role of TSG in inflammatory response in the central nervous system.

Simultaneous determination of seven hydrophilic bioactive compounds in water extract of Polygonum multiflorum using pressurized liquid extraction and short-end injection micellar electrokinetic chromatography

Background

Polygoni Multiflori Radix, He-Shou-Wu in Chinese, is a widely used traditional Chinese medicine. Clinically, water decoction is the major application form of He-Shou-Wu. Therefore, simultaneous determination of bioactive compounds in water extract is very important for its quality control.

Results

A pressurized liquid extraction and short-end injection micellar electrokinetic chromatography (MEKC) were first developed for simultaneous determination of seven hydrophilic bioactive compounds in water extract of He-Shou-Wu. The influence of parameters, such as pH, concentration of phosphate, SDS and HP-β-CD, capillary temperature and applied voltage, on the analysis were carefully investigated. Optimum separation was obtained within 14 min by using 50 mM phosphate buffer containing 90 mM SDS and 2% (m/v) HP-β-CD (pH 2.5) at 15 kV and 20°C. All calibration curves showed good linearity (R²>0.9978) within test ranges. The overall LOD and LOQ were lower than 2.0 μg/mL and 5.5 μg/mL, respectively. The RSDs for intra- and inter-day of seven analytes were less than 3.2% and 4.6%, and the recoveries were 97.0%-104.2%.

Conclusion

The validated method was successfully applied to the analysis of He-Shou-Wu samples, which is helpful for its quality control.

The effect of 2,3,4',5-tetrahydroxystilbene-2-0-β-D glucoside on neointima formation in a rat artery balloon injury model and its possible mechanisms

2,3,4',5-tetrahydroxystilbene-2-0-β-D glucoside (TSG) has been recognized to suppress the proliferation of vascular smooth muscle cells (VSMCs). The aim of the present study was to determine whether TSG inhibits neointimal hyperplasia in a rat carotid arterial balloon injury model. Balloon injury was induced in the left common carotid artery of rats. TSG (30, 60, 120 mg/kg/day) was treated from 3 days prior to, until 14 days after the induction of balloon injury. The ratio of intima-to-media was significantly reduced in the TSG-treated rats at 14 days after the induction of injury, which was associated with reduced expressions of proliferating cell nuclear antigen (PCNA), α-smooth muscle actin (α-SMA) and platelet-derived growth factor-BB (PDGF-BB), as markers of VSMCs proliferation and migration. Additionally, TSG significantly inhibited PDGF-BB induced cell migration in cultured VSMCs. Furthermore, we explored the underlying mechanisms for such effects of TSG. The result showed that TSG markedly reduced balloon injury-induced AKT, extracellular signal-regulated kinase (ERK1/2) and nuclear factor kappaB (NF-κB) activation as well as mRNA expressions of c-myc, c-fos and c-jun, which is important signal pathway for VSMCs proliferation. And in both vivo and vitro model, TSG markedly regulated matrix metalloproteinase-2, 9 expressions and collagen I, III expressions, which are key factors in extracellular matrix for VSMCs migration. These results suggest that the anti-proliferative and anti-migrative effects of TSG on VSMCs could help to explain the beneficial effects of TSG on neointima hyperplasia induced by balloon injury.

Proteomic analysis for anti-atherosclerotic effect of tetrahydroxystilbene glucoside in rats

2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside (TSG) extracted from Polygonum multiflorum (a traditional Chinese medicinal herb) has been proved to exhibit significant anti-atherosclerotic activity. In this study, we firstly used proteomic analyses to investigate the molecular events occurring in the atherosclerotic rats after TSG treatment. Aortic samples were collected from the atherosclerotic rat group and the TSG-treated group, and its proteome was analyzed by two-dimensional gel electrophoresis (2-DE). Proteins showing significant changes in expression were identified and analyzed by matrix-assisted desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS). As a result, 21 protein spots were found with significant differential expression after the treatment with TSG. A total of 18 spots were identified by database searching, and 17 spots matched with known proteins. Among these proteins (11 proteins up-regulated and six proteins down-regulated), five proteins were mainly involved in inflammation, cholesterol transport, cell apoptosis and adhesion. TSG treatment enhanced the expression of HSP 70, lipocortin 1 and Apo A-I, and inhibited the expression of calreticulin, vimentin. Furthermore, we randomly selected four proteins and confirmed the results of proteomic analysis by RT-PCR and western blotting. In conclusion, TSG treatment suppresses atherosclerosis by altering the expression of different proteins. Calreticulin, vimentin, HSP 70, lipocortin 1, and Apo A-I, are key proteins that may be novel molecular targets responsible for atherogenesis suppression induced by TSG treatment.

2,3,4',5-tetrahydroxystilbene-2-O-β-D-glucoside inhibits proliferation of vascular smooth muscle cells: involvement of NO/cGMP/PKG pathway

The proliferation of vascular smooth muscle cells (VSMCs) induced by injury to the intima of arteries is an important etiologic factor in vascular proliferative disorders such as atherosclerosis and restenosis. 2,3,4',5-Tetrahydroxystilbene-2-O-β-D-glucoside (TSG), an active component extracted from Polygonum multiflorum, has been found to have an antiatherosclerotic effect. The aim of this study was to investigate the effects of TSG on platelet derived growth factor (PDGF)-BB induced VSMCs proliferation and to explore the possible mechanisms of such effects. Pretreatment of VSMCs with TSG significantly inhibited PDGF-BB-induced cell proliferation in a concentration-dependent but not time-dependent manner. In addition, flow cytometry analysis of the DNA content revealed blocking of the PDGF-BB-inducible cell cycle progression by TSG. On the contrary, an inhibitory effect of TSG on VSMCs proliferation and expression of cell cycle regulators were markedly attenuated by addition of an nitric oxide (NO) synthase inhibitor, a soluble guanylate cyclase inhibitor and a cyclic GMP (cGMP)-dependent protein kinase (PKG) inhibitor: N(G)-nitro-L-arginine methyl ester (L-NAME), 1H-[1,2,4] oxadiazolo [4,3-α] quinoxalin-1-one (ODQ) and KT5823, respectively. It was also demonstrated that TSG enhanced NO and cGMP formation through up-regulating endothelial NO synthase expression in VSMCs. The findings indicate that TSG inhibited VSMCs proliferation induced by PDGF-BB may involve the NO/cGMP/PKG signal pathway.