Effects of Homocysteine and Ginsenoside Rb1 on Endothelial Proliferation and Superoxide Anion Production

Increasing Expression of PnGAP and PnEXPA4 Provides Insights Into the Enlargement of Panax notoginseng Root Size From Qing Dynasty to Cultivation Era

Root size is a key trait in plant cultivation and can be influenced by the cultivation environment. However, physical evidence of root size change in a secular context is scarce due to the difficulty in preserving ancient root samples, and how they were modified during the domestication and cultivation stays unclear. About 100 ancient root samples of Panax notoginseng, preserved as tribute in the Palace Museum (A.D. 1636 to 1912, Qing dynasty), provided an opportunity to investigate the root size changes during the last 100 years of cultivation. The dry weight of ancient root samples (~120 tou samples, tou represents number of roots per 500 g dry weight) is 0.22-fold of the modern samples with the biggest size (20 tou samples). Transcriptome analysis revealed that PnGAP and PnEXPA4 were highly expressed in 20 tou samples, compared with the 120 tou samples, which might contribute to the thicker cell wall and a higher content of lignin, cellulose, and callose in 20 tou samples. A relatively lower content of dencichine and higher content of ginsenoside Rb1 in 20 tou samples are also consistent with higher expression of ginsenoside biosynthesis-related genes. PnPHL8 was filtrated through transcriptome analysis, which could specifically bind the promoters of PnGAP, PnCYP716A47, and PnGGPPS3, respectively. The results in this study represent the first physical evidence of root size changes in P. notoginseng in the last 100 years of cultivation and contribute to a comprehensive understanding of how the cultivation environment affected root size, chemical composition, and clinical application.

Ginseng in vascular dysfunction: A review of therapeutic potentials and molecular mechanisms

Vascular dysfunction can lead to a variety of fatal diseases, including cardiovascular and cerebrovascular diseases, metabolic syndrome, and cancer. Although a large number of studies have reported the therapeutic effects of natural compounds on vascular‐related diseases, ginseng is still the focus of research. Ginseng and its active substances have bioactive effects against different diseases with vascular dysfunction. In this review, we summarized the key molecular mechanisms and signaling pathways of ginseng, its different active ingredients or formula in the prevention and treatment of vascular‐related diseases, including cardiac‐cerebral vascular diseases, hypertension, diabetes complications, and cancer. Moreover, the bidirectional roles of ginseng in promoting or inhibiting angiogenesis have been highlighted. We systematically teased out the relationship between ginseng and vascular dysfunction, which could provide a basis for the clinical application of ginseng in the future.

Ginseng in vascular dysfunction: A review of therapeutic potentials and molecular mechanisms

Vascular dysfunction can lead to a variety of fatal diseases, including cardiovascular and cerebrovascular diseases, metabolic syndrome, and cancer. Although a large number of studies have reported the therapeutic effects of natural compounds on vascular-related diseases, ginseng is still the focus of research. Ginseng and its active substances have bioactive effects against different diseases with vascular dysfunction. In this review, we summarized the key molecular mechanisms and signaling pathways of ginseng, its different active ingredients or formula in the prevention and treatment of vascular-related diseases, including cardiac-cerebral vascular diseases, hypertension, diabetes complications, and cancer. Moreover, the bidirectional roles of ginseng in promoting or inhibiting angiogenesis have been highlighted. We systematically teased out the relationship between ginseng and vascular dysfunction, which could provide a basis for the clinical application of ginseng in the future.

Ginsenoside Rb1 inhibits vascular calcification as a selective androgen receptor modulator

Ginsenoside Rb1 (Rb1), a major component of ginseng, has a steroidal chemical structure, implying that it exerts sex hormone-like actions. Recent studies have been suggested cardioprotective actions of Rb1. However, the actions of Rb1 in vascular calcification, one of the significant pathological features associated with aging and atherosclerosis, have not been examined. In the present study, we examined the effects of Rb1 on vascular calcification, focusing on its androgen-like actions. Using inorganic phosphate (Pi)-induced calcification of vascular smooth muscle cells (VSMC), we found that Rb1, like testosterone, significantly inhibited calcium deposition in a concentration-dependent manner. Further, this inhibition of Rb1 was abolished by bicalutamide, an androgen receptor antagonist, but not by MPP or PHTPP, estrogen receptor α or β antagonists. Rb1 significantly inhibited apoptosis, one of the regulatory mechanisms of calcification, and restored growth arrest-specific gene 6 (Gas6) expression that was suppressed by Pi. Moreover, Rb1 transactivated Gas6, and proximal androgen-responsive element (ARE) of the promoter region was found to be crucial for Gas6 transactivation. In contrast, in a human prostate cancer cell line, testosterone-induced ARE activity was abrogated by Rb1. This antagonistic effect was also confirmed by the transrepression and downregulation of prostate-specific antigen in the presence of testosterone and Rb1 together. Thus, these findings provide a novel mechanistic insight into the vasculoprotective actions of Rb1 as a selective androgen receptor modulator, i.e., inhibitory effects on VSMC calcification through androgen receptor-mediated Gas6 transactivation and antagonistic effects in prostate cancer cells.

Ginsenoside Rb1 Blocks Ritonavir-Induced Oxidative Stress and eNOS Downregulation through Activation of Estrogen Receptor-Beta and Upregulation of SOD in Human Endothelial Cells

We have previously shown that ritonavir (RTV), a highly active anti-retroviral therapy (HAART) drug, can cause endothelial dysfunction through oxidative stress. Several antioxidants including ginsenoside Rb1, a compound with antioxidant effect, can effectively block this side effect of RTV in endothelial cells. In the current study, we explored a mechanism by which ginsenoside Rb1 could protect these cells via binding of estrogen receptors (ERs). We found that several human endothelial cell lines differentially expressed ER-β and had very low levels of ER-α. RTV treatment significantly increased the production of reactive oxygen species (ROS) and decreased the expression of endothelial nitric oxidase synthase (eNOS) and superoxide dismutase (SOD) in HUVECs, while Rb1 effectively blocked these effects of RTV. These effects of Rb1 were effectively inhibited by silencing ER-β, indicating that ginsenoside Rb1 requires ER-β for its antioxidant activity in inhibiting the deleterious effect of RTV in human endothelial cells. Furthermore, Rb1 specifically activated ER-β transactivation activity by ER-β luciferase reporter assay. Rb1 competitively bound to ER-β, which was determined by the high sensitive fluorescent polarization assay.

Effects of ginsenoside Rb1 on oxidative stress injury in rat spinal cords by regulating the eNOS/Nrf2/HO-1 signaling pathway

The present study aimed to investigate whether ginsenoside Rb1 (G-Rb1) attenuates spinal cord injury-associated oxidative stress in rats by regulating the endothelial nitric oxide synthase eNOS/nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase (HO)-1 signaling pathway. Sprague Dawley rats were randomly divided into the sham operation group (S group), spinal cord injury group (SCI group), G-Rb1 treatment group (G-Rb1 group) and SCI+G-Rb1+Inhibitor L-name group (L-name group). The posterior limb function was evaluated via the Basso, Beattie and Bresnahan scoring method. The levels of superoxide dismutase (SOD), malondialdehyde (MDA), catalase (CAT) and glutathione (GSH) in serum were measured by ELISA. The pathological changes in the spinal cord were observed by H&E staining. Reverse transcription-quantitative polymerase chain reaction and western blot analyses were used to detect eNOS, phosphorylated (p)-eNOS, heat shock protein (HSP)90, Nrf2 and NAD(P)H quinone dehydrogenase 1 (Nqo1) at the mRNA and protein level. Immunohistochemistry was used to detect the expression of Nrf2 and p-eNOS. Compared with the S group, the scores of spinal cord function in the SCI group were significantly lower, and the levels of MDA were significantly increased, while the levels of SOD, CAT and GSH protein in spinal cord were significantly decreased (P<0.05). The spinal cord tissue exhibited hemorrhage, neuronal degeneration/necrosis, as well as mononuclear cell and lymphocyte infiltration. The eNOS, HSP90, Nrf2, Nqo1 and HO-1 mRNA levels were decreased (P<0.05). Compared with those in the SCI group, the spinal cord function score in the G-Rb1 group were significantly higher and the serum MDA content was significantly decreased, while the activity of SOD, CAT and GSH was significantly increased (P<0.05). The degeneration/necrosis of spinal cord neurons was attenuated, inflammatory cell infiltration was significantly reduced and the levels of eNOS, HSP90, Nrf2, Nqo1 and HO-1 were significantly upregulated (P<0.05). In the group that was administered the eNOS inhibitor L-name, the levels of eNOS, HSP90, Nrf2, Nqo1 and HO-1 were significantly decreased. In conclusion, G-Rb1 attenuates oxidative stress in injured spinal cords. The mechanism may at least in part involve the eNOS/Nrf2/HO-1 pathway.

Ginsenoside Rb1 prevents homocysteine-induced EPC dysfunction via VEGF/p38MAPK and SDF-1/CXCR4 activation

Hyperhomocystinemia (HHcy) is known as an independent risk factor for cardiovascular disease. Our previous study showed that ginsenoside Rb1, the major active constituent of ginseng, prevents homocysteine (Hcy)-induced endothelial damage. However, the role of ginsenoside Rb1 in Hcy-induced dysfunction in endothelial progenitor cells (EPCs) remains unknown. In the study, we found that ginsenoside Rb1 reversed the Hcy-induced impairment of adhesive and migratory ability in EPCs which were significantly abolished by CXCR4 antagonist AMD3100 and VEGFR2 inhibitor SU5416. Ginsenoside Rb1 significantly reversed Hcy-induced SDF-1 reduction in the supernatant and in the serum. Ginsenoside Rb1 reversed downregulation of SDF-1 and VEGFR2 protein expression, inhibition of p38MAPK phosphorylation induced by Hcy. Re-endothelialization in balloon-injured carotid arteries significantly increased with EPCs transplant, and was even better with Rb1 treatment. This effect was significantly abolished by AMD3100. AMD3100 also decreased the number of CM-DiI labeled EPCs in injured arteries. Here we show for the first time that Rb1 prevents Hcy-induced EPC dysfunction via VEGF/p38MAPK and SDF-1/CXCR4 activation. These findings demonstrate a novel mechanism of the action of Rb1 that may have value in prevention of HHcy associated cardiovascular disease.

The Effects of Homocysteine Level in the Critically Ill Patient. A Review

Increased levels of homocysteine (HCYS) represent a risk factor for a series of physiopathological conditions: mental retardation, cardiovascular and neurodegenerative diseases, Parkinson's and Alzheimer's disease, depression, osteoporosis, endothelial dysfunction and inhibition of cell proliferation. This paper aims to present the pathophysiological implications of HCYS and the correlation of hyperhomocysteinemia (H-HCYS) with critical condition in the intensive care unit (ICU). Hypovitaminosis B and folate deficiency is directly involved in the inhibition of HCYS metabolism and the accumulation of HCYS in the plasma and tissues. Critically ill patients are more prone to H-HCYS due to hypermetabolism and accelerated synthesis produced by reactive oxygen species (ROS). In conclusion it can be affirmed that the determination and monitoring of HCYS plasma levels may be of interest in optimizing the therapy for critically ill patients. Moreover, by controlling HCYS levels, and implicitly the essential cofactors that intervene in the specific biochemical pathways, such as vitamin B6, vitamin B12 and folic acid can provide a diversified and personalized treatment for each patient.

A combination of the main constituents of Fufang Xueshuantong Capsules shows protective effects against streptozotocin-induced retinal lesions in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Fufang Xueshuantong Capsule, an herbal formula licensed for clinical use in China, which is composed of Panax notoginseng (Burkill) F.H. Chen, Salvia miltiorrhiza Bunge, Astragalus membranaceus (Fisch.) Bunge, and Scrophularia ningpoensis Hemsl, has proven effective for the treatment of diabetic retinopathy. However, its bioactive constituents are still ambiguous. In this study, the therapeutic effects of a combination of the main constituents of Fufang Xueshuantong Capsule (cFXT) were evaluated in streptozotocin (STZ)-induced retinal lesions to identify the bioactive constituents.

METHODS

Sprague-Dawley rats, except for those in the control group (vehicle+vehicle), were administered a single injection of 60mg/kg STZ. One-week later, STZ-treated rats were randomly divided into three groups-one STZ group (STZ+vehicle) and two cFXT treatment groups (STZ+cFXT). The rats in the latter two groups received cFXT 44.8mg/kg or cFXT 22.4mg/kg by intragastric gavage once per day, for 24 consecutive weeks. The rats in the control and STZ groups received the vehicle in the same way. Body weights and fasting blood glucose levels were recorded every four weeks. After treatment, hemorheological tests were performed to record the erythrocyte aggregation indexes, blood viscosity, and plasma viscosity. The trypsin digestion method was used to observe pericyte and acellular capillary counts in the retina. Ultraviolet spectrophotometry was utilized to measure the activity of aldose reductase (AR) by measuring the nicotinamide adenine dinucleotide phosphate (NADPH) consumption at 340nm. An immunohistochemical assay was used to observe the expressions of vascular endothelial growth factor (VEGF) and pigment epithelium-derived factor (PEDF) in the retina. The expression levels of intercellular adhesion molecule-1 (ICAM-1), endothelin-1 (RT-1),and occludin in the retina were tested by the western blot assay.

RESULTS

cFXT is composed of 991.44mg/g saponins of Panax notoginseng, 1.62mg/g harpagoside, 0.70mg/g cryptotanshinone, 0.74mg/g tanshinone I, and 5.50mg/g astragaloside A. Although it showed no effects on the increased body weight and blood glucose levels induced by STZ in rats. However, it showed a tendency to attenuate the increase in erythrocyte aggregation, plasma viscosity, and acellular vessel and pericyte loss, paralleled with a reversal of the hyper-activation of AR, the hyper-expression of VEGF, ICAM-1, and ET-1, and the hypo-expression of PEDF and occludin in the retinas of STZ-treated rats.

CONCLUSION

The saponins of Panax notoginseng, harpagoside, cryptotanshinone, tanshinone I, and astragaloside A are the main bioactive constituents of Fufang Xueshuantong Capsule and contribute to the attenuation of STZ-induced retinal lesions in rats. These constituents can be used as the base to optimize a new drug for the treatment of diabetic retinopathy, and can be selected for quality control of Fufang Xueshuantong Capsules.

Ginseng: a promising neuroprotective strategy in stroke

Ginseng is one of the most widely used herbal medicines in the world. It has been used in the treatment of various ailments and to boost immunity for centuries; especially in Asian countries. The most common ginseng variant in traditional herbal medicine is ginseng, which is made from the peeled and dried root of Panax Ginseng. Ginseng has been suggested as an effective treatment for a vast array of neurological disorders, including stroke and other acute and chronic neurodegenerative disorders. Ginseng’s neuroprotective effects are focused on the maintenance of homeostasis. This review involves a comprehensive literature search that highlights aspects of ginseng’s putative neuroprotective effectiveness, focusing on stroke. Attenuation of inflammation through inhibition of various proinflammatory mediators, along with suppression of oxidative stress by various mechanisms, including activation of the cytoprotective transcriptional factor Nrf2, which results in decrease in reactive oxygen species, could account for its neuroprotective efficacy. It can also prevent neuronal death as a result of stroke, thus decreasing anatomical and functional stroke damage. Although there are diverse studies that have investigated the mechanisms involved in the efficacy of ginseng in treating disorders, there is still much that needs to be clarified. Both in vitro and in vivo studies including randomized controlled clinical trials are necessary to develop in-depth knowledge of ginseng and its practical applications.

Bidirectional regulation of angiogenesis and miR-18a expression by PNS in the mouse model of tumor complicated by myocardial ischemia

Background

Panax Notoginseng Saponins (PNS) is the major class of active constituents of notoginseng, a natural product extensively used as a therapeutic agent in China. Tumor when accompanied by cardiovascular disorders poses a greater challenge for clinical management given the paradoxical involvement of angiogenesis, therefore gaining increased research attention. This study aim to investigate effects of PNS and its activity components in the mouse model of tumor complicated with myocardial ischemia.

Methods

Tumor complexed with myocardial ischemia mouse model was first established, which was followed by histological and immunohistochemistry examination to assess the effect of indicated treatments on tumor, myocardial ischemia and tissue specific angiogenesis. MicroRNA (miRNA) profiling was further carried out to identify potential miRNA regulators that might mechanistically underline the therapeutic effects of PNS in this complex model.

Results

PNS and its major activity components Rg1, Rb1 and R1 suppressed tumor growth and simultaneously attenuated myocardial ischemia. PNS treatment led to decreased expression of CD34 and vWF in tumor and increased expression of these vascular markers in heart. PNS treatment resulted in reduced expression of miR-18a in tumor and upregulated expression of miR-18a in heart.

Conclusions

Our data demonstrated for the first time that PNS exerts tissue specific regulatory effects on angiogenesis in part through modulating the expression of miR-18a, which could be responsible for its bidirectional effect on complex disease conditions where paradoxical angiogenesis is implicated. Therefore, our study provides experimental evidence warranting evaluation of PNS and related bioactive component as a rational therapy for complex disease conditions including co-manifestation of cancer and ischemic cardiovascular disease.

Fo Shou San, an ancient Chinese herbal decoction, protects endothelial function through increasing endothelial nitric oxide synthase activity

Fo Shou San (FSS) is an ancient herbal decoction comprised of Chuanxiong Rhizoma (CR; Chuanxiong) and Angelicae Sinensis Radix (ASR; Danggui) in a ratio of 2:3. Previous studies indicate that FSS promotes blood circulation and dissipates blood stasis, thus which is being used widely to treat vascular diseases. Here, we aim to determine the cellular mechanism for the vascular benefit of FSS. The treatment of FSS reversed homocysteine-induced impairment of acetylcholine (ACh)-evoked endothelium-dependent relaxation in aortic rings, isolated from rats. Like radical oxygen species (ROS) scavenger tempol, FSS attenuated homocysteine-stimulated ROS generation in cultured human umbilical vein endothelial cells (HUVECs), and it also stimulated the production of nitric oxide (NO) as measured by fluorescence dye and biochemical assay. In addition, the phosphorylation levels of both Akt kinase and endothelial NO synthases (eNOS) were markedly increased by FSS treatment, which was abolished by an Akt inhibitor triciribine. Likewise, triciribine reversed FSS-induced NO production in HUVECs. Finally, FSS elevated intracellular Ca(2+) levels in HUVECs, and the Ca(2+) chelator BAPTA-AM inhibited the FSS-stimulated eNOS phosphorylation. The present results show that this ancient herbal decoction benefits endothelial function through increased activity of Akt kinase and eNOS; this effect is causally via a rise of intracellular Ca(2+) and a reduction of ROS.

Ginsenoside Rb1 reverses H2O2-induced senescence in human umbilical endothelial cells: involvement of eNOS pathway

OBJECTIVE

Senescence of endothelial cells has been implicated in endothelial dysfunction and atherogenesis. This study investigated the effects of Rb1, a major ginsenoside in ginseng, on H2O2-induced senescence in primary human umbilical vein endothelial cells (HUVECs).

METHODS AND RESULTS

Real-time PCR and Western blot were used to detect the mRNA and protein expression, respectively. H2O2 (40∼100 μmol/L) effectively increased SA-β-gal activity and PAI-1 mRNA levels, two important senescence related biomarkers, in HUVECs, which were dramatically inhibited by Rb1 pre-incubation. Furthermore, Rb1 administration reversed the H2O2-decreased protein and mRNA levels of eNOS and its phosphorylation at Ser-1177, and the increased eNOS phosphorylation at Thr-495. As a result, Rb1 pretreatment restored the NO generation, as assayed by nitrate reductase method. However, pretreatment with L-NAME, a NOS inhibitor, abolished all the inhibitory effects of Rb1 on senescence. Importantly, Rb1 modulated the H2O2-altered caveolin-1 and pAkt, two most important regulators of eNOS expression and activity, in HUVECs.

CONCLUSIONS

We showed that Rb1 effectively protects HUVECs from senescence through eNOS modulation.

Rb1 protects endothelial cells from hydrogen peroxide-induced cell senescence by modulating redox status

Senescence of endothelial cells has been proposed to play an important role in endothelial dysfunction and atherogenesis. In the present study we aimed to investigate whether ginsenoside Rb1, a major constituent of ginseng, protects endothelial cells from H(2)O(2)-induced endothelial senescence. While H(2)O(2) induced premature senescent-like phenotype of human umbilical vein endothelial cells (HUVECs), as judged by increased senescence-associated β-galactosidase (SA-β-gal) activity, enlarged, flattened cell morphology and sustained growth arrest, our results demonstrated that Rb1 protected endothelial cells from oxidative stress induced senescence. Mechanistically, we found that Rb1 could markedly increase intracellular superoxide dismutase (Cu/Zn SOD/SOD1) activity and decrease the malondialdehyde (MDA) level in H(2)O(2)-treated HUVECs, and suppress the generation of intracellular reactive oxygen species (ROS). Consistent with these findings, Rb1 could effectively restore the protein expression of Cu/Zn SOD, which was down-regulated in H(2)O(2) treated cells. Taken together, our data demonstrate that Rb1 exhibits antioxidant effects and antagonizes H(2)O(2)-induced cellular senescence.

Ginsenoside Rb1 inhibits cell activation and liver fibrosis in rat hepatic stellate cells

Chronic hepatitis/cirrhosis is the eighth leading cause of death in Taiwan. Excess accumulated extracellular matrix produced by activated hepatic stellate cells (HSCs) is the major cause of liver fibrosis. Ginsenoside Rb1, the most active compound purified from ginseng, has been considered to be hepatoprotective. This study investigated the effects of ginsenoside Rb1 (98.8% purity) on activation, proliferation, and profibrotic factors in rat HSC-T6 cells under H₂O₂ oxidative stress. Rat HSC-T6 cells were activated by 10 nM H₂O₂ and then incubated with different concentrations of ginsenoside Rb1 (5, 10, 20, 40, and 80 μg/mL) for 24 hours. Medium containing 0.08% dimethyl sulfoxide or 5 mM N-acetyl-l-cysteine was used as a negative or positive control, respectively. The results showed that ginsenoside Rb1 at 5-40 μg/mL significantly reduced α-smooth muscle actin levels and at 5-80 μg/mL inhibited cell proliferation in HSC-T6 cells after induction with H₂O₂ (P<.05). Collagen secreted by HSC-T6 cells was decreased by ginsenoside Rb1 at 5-80 μg/mL (P<.05). Protein expression of transforming growth factor-β1 (TGF-β1), matrix metalloproteinase (MMP)-2, and tissue inhibitor of metalloproteinase (TIMP)-1 was suppressed by ginsenoside Rb1 at 10-80 μg/mL (P<.05). In addition, mRNA expression of type I and III collagen, TGF-β1, and TIMP-1 was inhibited by ginsenoside Rb1 (10 and 80 μg/mL) (P<.05). Therefore, ginsenoside Rb1 exerted an antifibrotic effect on HSCs by inhibiting activation, proliferation, and expression of collagen, TGF-β1, MMP-2, and TIMP-1.

Ginsenoside Rb1 inhibits proliferation and inflammatory responses in rat aortic smooth muscle cells

Ginsenoside Rb1, a known phytoestrogen, is a major pharmacologically active component in ginseng. The present study was designed to investigate the effect of ginsenoside Rb1 on fetal bovine serum (FBS)-induced proliferation and tumor necrosis factor-α (TNF-α)-evoked inflammatory responses in cultured rat aortic vascular smooth muscle cells (VSMCs). The data showed that Rb1 potently inhibited VSMC proliferation and cell growth induced by 5% FBS. These inhibitory effects were associated with G(1) cell cycle arrest and down-regulation of cell cycle proteins. Treatment with Rb1 reduced FBS-induced extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation. Furthermore, TNF-α-evoked inflammatory responses were inhibited by Rb1. Reporter gene assay indicated that Rb1 could transactivate ERβ especially. Moreover, Rb1-mediated inhibition of VSMCs proliferation was greatly blocked by transfection of ERβ siRNA. These results suggest that Rb1 inhibits FBS-induced proliferation and TNF-α-evoked inflammatory responses in VSMCs. The findings presented here highlight the possible therapeutic use of Rb1 in cardiovascular disease.

Ginsenoside Rb1 prevents homocysteine-induced endothelial dysfunction via PI3K/Akt activation and PKC inhibition

Hyperhomocysteinemia (HHcy), a risk factor for cardiovascular disease, is associated with endothelial dysfunction. Ginsenoside Rb1, the major active constituent of ginseng, potently attenuates homocysteine (Hcy)-induced endothelial damage. However, the underlying mechanism remains unknown. In this study, we have investigated the effect of Ginsenoside Rb1 on Hcy-induced endothelial dysfunction and its underlying signal pathway in vivo and in vitro. Ginsenosides prevented Hcy-induced impairment of endothelium-dependent relaxation and Rb1 reversed Hcy-induced reduction of NO production in a dose-dependent manner as detected by nitrate reductase method. Rb1 activated serine-1177 phosphorylation of endothelial nitric oxide synthase (eNOS) and serine-473 phosphorylation of Akt, while inhibited threonine-495 phosphorylation of eNOS as detected by western blotting. Rb1-induced phosphorylation of serine-1177 was significantly inhibited by wortmannin, PI3K inhibitor or SH-5, an Akt inhibitor, and partially reversed by Phorbol 12-myristate 13-acetate (PMA), a PKC activator. PMA also stimulated phosphorylation of threonine-495 which was inhibited by Rb1. Here we show for the first time that Rb1 prevents Hcy-induced endothelial dysfunction via PI3K/Akt activation and PKC inhibition. These findings demonstrate a novel mechanism of the action of Rb1 that may have value in prevention of HHcy associated cardiovascular disease.

The effects of ginsenoside Rb1 on endothelial damage and ghrelin expression induced by hyperhomocysteine

OBJECTIVE

Studies have indicated that ginsenoside Rb1 and ghrelin could both prevent homocysteine (Hcy)-induced endothelial dysfunction through the endothelial nitric oxide synthase (eNOS)/nitric oxide (NO) mechanism. This study investigated whether endogenous ghrelin mediates the endothelial protection of ginsenosidee Rb1 through in vitro and in vivo experiments.

METHODS

Rats were randomized into a control group, a hyperhomocysteine (HHcy) model group with a high methionine diet, a ginsenosides (GS) group, and HHcy plus GS group. Plasma ghrelin was detected by enzyme-linked immunosorbent assay. Aortic rings for control and HHcy groups were treated with ghrelin or not. Endothelium-dependent vasodilatation function was evaluated by the aortic ring assay, and the structural changes were visualized by hematoxylin and eosin staining. Human umbilical vein endothelial cells (HUVECs) were cultured, and the experimental conditions were optimized according to NO production. After treatment, the NO, ghrelin, and von Willebrand factor (vWF) levels in the media were detected and analyzed with linear regression. Ghrelin and eNOS expression were observed by cell immunohistochemical staining. Ghrelin receptor antagonist was used to detect the mechanism of ginsenoside Rb1 on NO production, which was reflected by diacetylated 4,5-diaminofluorescein-2 diacetate fluorescence.

RESULTS

In vivo experiments demonstrated that plasma ghrelin levels in the HHcy group were significantly elevated vs controls (P < .05) and were significantly increased in the HHcy plus GS group (P < .01). Compared with control, endothelium-dependent vasodilatation function was greatly reduced in the HHcy group (P < .01), which was significantly increased in HHcy plus ghrelin group compared with HHcy group (P < .01). The arterial walls of HHcy group exhibited characteristic pathologic changes, which were repaired in HHcy plus ghrelin group. In vivo, compared with Hcy (200 μM) group, HUVECs pretreated with ginsenoside Rb1 (10 μM) for 30 minutes showed significant increases in NO and ghrelin levels and evident reduction in vWF levels. Linear regression analysis demonstrated that ghrelin levels were significantly positively correlated with NO levels and significantly negatively correlated with vWF levels. The addition of Rb1 to Hcy also greatly reversed Hcy-induced downregulation of ghrelin and eNOS expression. Ghrelin inhibition significantly abolished the upregulation of NO levels induced by Rb1.

CONCLUSION

Ghrelin can prevent Hcy-induced vascular endothelial dysfunction and structural damage. The compensatory elevation of plasma ghrelin levels in an Hcy-induced endothelial injury model may be a protective response. Ginsenoside Rb1 can significantly stimulate the ghrelin endocrine to inhibit endothelial injury. Ginsenoside also upregulates the NO signaling pathway reduced by Hcy through the ghrelin molecular mechanism.

In vivo assessment of the effects of ginsenoside Rb1 on intimal hyperplasia in ApoE knockout mice

OBJECTIVE

This study investigated the effects of ginsenoside Rb1 (Rb1) on injury-induced intimal hyperplasia in ApoE knock out (ApoE -/-) mice. We also examined the value of an ultrasound micro-image system in dynamic monitoring of lumen diameter and flow velocity.

METHODS

After guide wire injury of the distal left common carotid artery (CCA), ApoE-/- mice were treated with intraperitoneal infusion of normal saline (NS), homocysteine (Hcy), ginsenoside Rb1 (Rb1), or Hcy+Rb1 for 4 wk. Bilateral CCA luminal diameters and flow velocities were measured with an ultrasound micro-image system before surgery and weekly afterwards. Following the final ultrasound, CCAs were harvested and analyzed for intima-medium thickness ratios.

RESULTS

Progressive reduction in luminal diameters and increase in flow velocity of the injured left distal CCA segment were observed using ultrasound micro-imaging system in all groups compared with the relatively stable left proximal CCA and right CCA. The NS and Hcy groups had significantly higher degree of diameter reduction compared with the Rb1 and Rb1+Hcy groups. The ultrasound findings were consistent with histology analyses at 4 wk post-op.

CONCLUSIONS

The study suggested that Rb1 attenuated the effects of Hcy on injured carotid arteries of ApoE -/- mice. The study also showed that ultrasound micro-image system was a reliable tool in monitoring luminal reduction after injury in a murine model. This study establishes a fundamental step of in vivo monitoring of the therapeutic effects of agents in a murine model without sacrificing the animals.

American ginseng supplementation induces an oxidative stress in postmenopausal women

OBJECTIVE

To determine whether American ginseng (Panax Quinquefolium) confers antioxidant protection to postmenopausal women at rest and after a mild aerobic exercise session.

METHODS

In this double-blinded parallel study, 12 female subjects (age range 55-75) consumed two capsules, containing 500 mg of dry American ginseng whole-root powder, everyday for 4 months, whereas 13 female control subjects of the same age range consumed two placebo capsules. Before and after the supplementation regimen each subject performed 30 minutes of treadmill walking on a 5% grade incline at an estimated 60% of VO(2)max.

RESULTS

Ginseng supplementation had no effect on heart rate, blood pressure, plasma blood glucose, or lactate concentration at rest or immediately after exercise tests. The ginseng supplemented group displayed a higher resting plasma glutathione disulfide (GSSG) concentration and lower glutathione (GSH):GSSG ratio, as well as a lower resting total antioxidant content (TAC). Plasma GSSG concentration decreased, whereas the GSH:GSSG ratio and TAC increased after exercise in all subjects. Furthermore, plasma malondialdehyde and urine 8-hydroxydeoxyguanosine concentrations were elevated in the ginseng-supplemented group. Erythrocyte superoxide dismutase and GSH reductase activities were increased after ginseng supplementation. The 30-minute treadmill walking, however, did not alter these changes.

CONCLUSIONS

These data suggest that chronic American ginseng supplementation at the given dose can cause an oxidative stress in postmenopausal women, as reflected by the elevated oxidative damage markers and the increased erythrocyte antioxidant enzyme activity.

Ginseng compounds: an update on their molecular mechanisms and medical applications

Ginseng is one of the most widely used herbal medicines and is reported to have a wide range of therapeutic and pharmacological applications. Ginsenosides, the major pharmacologically active ingredients of ginseng, appear to be responsible for most of the activities of ginseng including vasorelaxation, antioxidation, anti-inflammation and anti-cancer. Approximately 40 ginsenoside compounds have been identified. Researchers now focus on using purified individual ginsenoside to reveal the specific mechanism of functions of ginseng instead of using whole ginseng root extracts. Individual ginsenosides may have different effects in pharmacology and mechanisms due to their different chemical structures. Among them the most commonly studied ginsenosides are Rb1, Rg1, Rg3, Re, Rd and Rh1. The molecular mechanisms and medical applications of ginsenosides have attracted much attention and hundreds of papers have been published in the last few years. The general purpose of this update is to provide information of recently described effects of ginsenosides on antioxidation, vascular system, signal transduction pathways and interaction with receptors. Their therapeutic applications in animal models and humans as well as the pharmacokinetics and toxicity of ginsenosides are also discussed in this review. This review concludes with some thoughts for future directions in the further development of ginseng compounds as effective therapeutic agents.

Ginseng compounds: an update on their molecular mechanisms and medical applications

Ginseng is one of the most widely used herbal medicines and is reported to have a wide range of therapeutic and pharmacological applications. Ginsenosides, the major pharmacologically active ingredients of ginseng, appear to be responsible for most of the activities of ginseng including vasorelaxation, antioxidation, anti-inflammation and anti-cancer. Approximately 40 ginsenoside compounds have been identified. Researchers now focus on using purified individual ginsenoside to reveal the specific mechanism of functions of ginseng instead of using whole ginseng root extracts. Individual ginsenosides may have different effects in pharmacology and mechanisms due to their different chemical structures. Among them the most commonly studied ginsenosides are Rb1, Rg1, Rg3, Re, Rd and Rh1. The molecular mechanisms and medical applications of ginsenosides have attracted much attention and hundreds of papers have been published in the last few years. The general purpose of this update is to provide information of recently described effects of ginsenosides on antioxidation, vascular system, signal transduction pathways and interaction with receptors. Their therapeutic applications in animal models and humans as well as the pharmacokinetics and toxicity of ginsenosides are also discussed in this review. This review concludes with some thoughts for future directions in the further development of ginseng compounds as effective therapeutic agents.

Ginsenoside Rb1, a panoxadiol saponin against oxidative damage and renal interstitial fibrosis in rats with unilateral ureteral obstruction

OBJECTIVE

To investigate the possible protective effect and mechanism of ginsenoside Rb1 against oxidative damage and renal interstitial fibrosis on rats with unilateral ureteral obstruction (UUO).

METHODS

In total, 80 male rats were randomly divided into 4 groups, 20 in each group: the sham operated group (SOR), UUO group, UUO with ginsenoside Rb1 treatment group (treated with intraperitoneal injection of 50 mg/ kg daily) and UUO with Losartan treatment group (as the positive control, treated with 20 mg/kg by gastrogavage per day). The rats were randomly sacrificed on day 3, 7 and 14 after surgery, respectively. The histopathologic changes of renal interstitial tissues were observed with Masson staining. The mRNA of transforming growth factor beta 1 (TGF-beta 1), collagen I and fibronectin were reversed transcribed and quantified by Real-time PCR. Enzyme-linked immunosorbent assay was used to quantitatively detect TGF-beta 1 and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels. P47phox protein expression was assessed by immunohistochemistry and Western blot analysis.

RESULTS

In the UUO model, the obstructed kidney showed typical features of progressive renal tubulointerstitial fibrosis, and the levels of TGF-beta1, collagen I and fibronectin increased (P<0.05). As compared with the UUO group, ginsennoside Rb1 significantly inhibited the interstitial fibrosis including tubular injury and collagen deposition, and decreased the levels of TGF-beta1 (P<0.05). Ginsenoside Rb1 also inhibited the heme oxygenase (HO-1) and 8-OHdG, two markers of oxidative stress (P<0.05). Moreover, ginsenoside Rb1 suppressed the expression of p47phox, a subunit of nicotinamide adeninedinucleotide phosphate (NADPH) oxidase (P<0.05).

CONCLUSION

Ginsenoside Rb1 can obviously inhibit renal interstitial fibrosis in rats with UUO, its mechanism possibly via against the oxidative damage and suppressing TGF-beta1 expression.

Growth hormone-releasing peptide ghrelin inhibits homocysteine-induced endothelial dysfunction in porcine coronary arteries and human endothelial cells

OBJECTIVE

Ghrelin, a novel growth hormone-releasing peptide, is implicated to play a protective role in cardiovascular tissues. However, it is not clear whether ghrelin protects vascular tissues from injury secondary to risk factors such as homocysteine (Hcy). This study investigated the effect and potential mechanisms of ghrelin on Hcy-induced endothelial dysfunction.

METHODS

Porcine coronary artery rings were incubated for 24 hours with ghrelin (100 ng/mL), Hcy (50 microM), or ghrelin plus Hcy. Endothelial vasomotor function was evaluated using the myograph tension model. The response to the thromboxane A(2)analog U46619, bradykinin, and sodium nitroprusside was analyzed. Endothelial nitric oxide synthase (eNOS) expression was determined using real-time polymerase chain reaction and immunohistochemistry staining, and superoxide anion production was documented lucigenin-enhanced chemiluminescence analysis. Human coronary artery endothelial cells (HCAECs) were treated with different concentrations of Hcy, ghrelin, or antighrelin receptor antibody for 24 hours, and eNOS protein levels were determined by Western blot analysis.

RESULTS

Maximal contraction with U46619 and endothelium-independent vasorelaxation with sodium nitroprusside were not different among the four groups. However, endothelium-dependent vasorelaxation with bradykinin (10(-6) M) was significantly reduced by 34% with Hcy compared with controls (P < .05). The addition of ghrelin to Hcy had a protective effect, with 61.6% relaxation, which was similar to controls (64.7%). Homocysteine significantly reduced eNOS expression, whereas ghrelin cotreatment effectively restored eNOS expression to the control levels. Superoxide anion levels, which were increased by 100% with Hcy, returned to control levels with ghrelin cotreatment. Ghrelin also effectively blocked the Hcy-induced decrease of eNOS protein levels in HCAECs in a concentration-dependent manner. Antighrelin receptor antibody effectively inhibited the effect of ghrelin.

CONCLUSION

Ghrelin has a protective effect in the porcine coronary artery by blocking Hcy-induced endothelial dysfunction, improving eNOS expression, and reducing oxidative stress. Ghrelin also shows a protective effect on HCACEs from the Hcy-induced decrease in eNOS protein levels. The effect of ghrelin is receptor-dependent. Thus, ghrelin administration may have beneficial effects in the treatment of vascular disease in patients with hyperhomocysteinemia.

Ginsenoside Rb1 attenuates homocysteine-augmented guidewire injury-induced intimal hyperplasia in mice

BACKGROUND

Intimal hyperplasia (IH) is the primary cause for post-angioplasty restenosis. The purpose of this study is to investigate the effects of homocysteine (Hcy) and ginsenoside Rb1 (Rb1) on IH using a guidewire injury animal model.

METHODS

In 12-wk-old C57BL/6J mice, the left common carotid artery (CCA) was denudated with a guidewire and the right CCA was used as the uninjured control. They were treated with saline (NS), Hcy, Rb1, or Hcy + Rb1 for 4 wk prior to sacrifice. Animals were sacrificed at 4, 6, or 8 wk. Both CCAs were harvested and intimal-medium thickness (IMT) ratios were calculated. Local macrophage distribution was also studied.

RESULTS

Histology analyses demonstrated consistent internal elastic lamina disruption and focal IH in the injured CCA segments. The degree of IH correlated to the lengths of time following injury. Hcy treated group had significant increase in IMT compared with the NS group (P < 0.05), while Rb1 group was similar to the NS group. In addition, Hcy + Rb1 group showed significant improvement in IMT compared with Hcy group (P < 0.01). Furthermore, Hcy significantly increased local macrophage content as compared with either lesion alone or Rb1 treated animals.

CONCLUSIONS

Our study showed that Hcy increased the degree of IH and macrophage content in the injured CCA and that Rb1 attenuated these adverse effects. These changes might be mediated through antioxidative effects of Rb1. Our data suggests a potential clinical application of ginseng in controlling Hcy-related vascular injuries.

The chemical and hydroxyl radical scavenging activity changes of ginsenoside-Rb1 by heat processing

The chemical and hydroxyl radical (*OH) scavenging activity changes of ginsenoside Rb(1) (Rb(1)) by heat processing were investigated in this study. Rb(1) was changed into 20(S)-Rg(3), 20(R)-Rg(3), Rk(1), and Rg(5) by heat processing through glucosyl elimination and epimerization of carbon-20 by SN1 reaction. The glucosyl moiety, separated from Rb(1), made Maillard reaction product (MRPs) with glycine. The generations of 20(S)-Rg(3) and MRPs were related to the increased OH scavenging activity of Rb(1) by heat processing.

Protective effects of ginsenoside Rb1 on human umbilical vein endothelial cells in vitro

Ginseng has beneficial effects on the cardiovascular system, but its underlying mechanism is unclear. This study investigated the effects of ginsenoside Rb1, a major constituent of ginseng, on the changes of lactate dehydrogenase (LDH) activity, nitric oxide (NO), tissue-type plasminogen activator (t-PA), and plasminogen activator inhibitor-1 (PAI-1) in oxidized low-density lipoprotein (oxLDL)-injuring endothelial cells. Human umbilical vein endothelial cells were cultured and divided into 6 groups (n = 6): control group, oxLDL alone group (100 mg/L), ginsenoside Rb1 alone group (10 microg/mL), oxLDL plus ginsenoside Rb1 groups (0.1, 1.0, and 10 microg/mL, respectively.). Twenty-four hours after treatment, LDH activity and concentrations of NO, t-PA, and PAI-1 in culture medium were measured while the expressions of endothelial nitric oxide synthase (eNOS), t-PA, and PAI-1 mRNA in endothelial cells were detected by reverse-transcriptase polymerase chain reaction. Compared with control group, oxLDL (100 mg/L) caused LDH activity, the expressions of eNOS and t-PA mRNA, and concentrations of NO and t-PA to significantly decrease (P < 0.05, respectively), and it also led to dramatic increase of PAI-1 mRNA and concentration (P < 0.05, respectively). Ginsenoside Rb1 alone did not demonstrate this ability. High-dose Rb1 (10 microg/mL) could block the effects of oxLDL on LDH activity, mRNA of eNOS, t-PA, and PAI-1, and concentrations of NO, t-PA, and PAI-1 (P < 0.05, respectively), and neither low-dose Rb1 (0.1 microg/mL) nor medium-dose Rb1 (1.0 microg/mL) demonstrated this ability. We conclude that ginsenoside Rb1 has protective effects on oxLDL-injuring human vascular endothelial cells and can reverse the effects of oxLDL on NO, t-PA, and PAI-1.

The effects of glycine and L-arginine on heat stability of ginsenoside Rb1

To identify the effects of amino acids on the heat stability of ginsenoside Rb(1) (Rb(1)), Rb(1) was heat-processed at 120 degrees C with or without glycine or L-arginine. Rb(1) was changed into 20(S)-Rg(3), 20(R)-Rg(3), Rk(1), and Rg(5) by heat-processing through glycosyl elimination and epimerization of carbon-20 by SN1 reaction. Similarly, Rb(1) was changed into 20(S)-Rg(3), 20(R)-Rg(3), Rk(1), and Rg(5) when it was heat-processed with the same amount of glycine, but the generated amount of 20(S)-Rg(3) was higher than when Rb(1) was heat-processed without amino acids, and a significant increase in Maillard reaction products (MRPs) was noted. On the other hand, there were no structural changes in Rb(1) and the generation of MRPs when Rb(1) was heat-processed with the same amount of L-arginine. The improved heat stability of Rb(1) brought about by the addition of L-arginine was thought to be closely related to its characteristics of interfering with nonenzymatic glycation and forming hydrogen bonds with Rb(1).