A Cocktail of Natural Compounds Holds Promise for New Immunotherapeutic Potential in Head and Neck Cancer

OBJECTIVE

To obtain detailed understanding on the gene regulation of natural compounds in altering prognosis of head and neck squamous cell carcinomas (HNSC).

METHODS

Gene expression data of HNSC samples and peripheral blood mononuclear cells (PBMCs) of HNSC patients were collected from Gene Expression Omnibus (GEO). Differential gene expression analysis of GEO datasets were achieved by the GEO2R tool. Common differentially expressed gerres (DEGs) were screened by comparing DEGs of HNSC with those of PBMCs. The combination was further analyzed for regulating pathways and biological processes that were affected.

RESULTS

Totally 110 DEGs were retrieved and identified to be involved in biological processes related to tumor regulation. Then 102 natural compounds were screened for a combination such that the expression of all 110 commonly DEGs was altered. A combination of salidroside, ginsenoside Rd, oridonin, britanin, and scutellarein was chosen. A multifaceted, multi-dimensional tumor regression was showed by altering autophagy, apoptosis, inhibiting cell proliferation, angiogenesis, metastasis and inflammatory cytokines production.

CONCLUSIONS

This study has helped develop a unique combination of natural compounds that will markedly reduce the propensity of development of drug resistance in tumors and immune evasion by tumors. The result is crucial to developing a combinatorial natural therapeutic cocktail with accentuated immunotherapeutic potential.

Effect of fermented red ginseng on gut microbiota dysbiosis- or immobilization stress-induced anxiety, depression, and colitis in mice

Background

Red ginseng (RG) alleviates psychiatric disorders. Fermented red ginseng (fRG) alleviates stress-induced gut inflammation. Gut dysbiosis causes psychiatric disorders with gut inflammation. To understand the gut microbiota-mediated action mechanism of RG and fRG against anxiety/depression (AD), we investigated the effects of RG, fRG, ginsenoside Rd, and 20(S)-β-D-glucopyranosyl protopanaxadiol (CK) on gut microbiota dysbiosis-induced AD and colitis in mice.

Methods

Mice with AD and colitis were prepared by exposing to immobilization stress (IS) or transplanting the feces of patients with ulcerative colitis and depression (UCDF). AD-like behaviors were measured in the elevated plus maze, light/dark transition, forced swimming, and tail suspension tests.

Results

Oral gavage of UCDF increased AD-like behaviors and induced neuroinflammation, gastrointestinal inflammation, and gut microbiota fluctuation in mice. Oral administration of fRG or RG treatment reduced UCDF-induced AD-like behaviors, hippocampal and hypothalamic IL-6 expression, and blood corticosterone level, whereas UCDF-suppressed hippocampal BDNF+NeuN+ cell population and dopamine and hypothalamic serotonin levels increased. Furthermore, their treatments suppressed UCDF-induced colonic inflammation and partially restored UCDF-induced gut microbiota fluctuation. Oral administration of fRG, RG, Rd, or CK also decreased IS-induced AD-like behaviors, blood IL-6 and corticosterone and colonic IL-6 and TNF-α levels, and gut dysbiosis, while IS-suppressed hypothalamic dopamine and serotonin levels increased.

Conclusion

Oral gavage of UCDF caused AD, neuroinflammation, and gastrointestinal inflammation in mice. fRG mitigated AD and colitis in UCDF-exposed mice by the regulation of the microbiota-gut-brain axis and IS-exposed mice by the regulation of the hypothalamic-pituitary-adrenal axis.

Ginseng Sprouts Attenuate Mortality and Systemic Inflammation by Modulating TLR4/NF-κB Signaling in an LPS-Induced Mouse Model of Sepsis

Sepsis leads to multi-organ failure due to aggressive systemic inflammation, which is one of the main causes of death clinically. This study aimed to evaluate whether ginseng sprout extracts (GSE) can rescue sepsis and explore its underlying mechanisms. C57BL/6J male mice (n = 15/group) were pre-administered with GSE (25, 50, and 100 mg/kg, p.o) for 5 days, and a single injection of lipopolysaccharide (LPS, 30 mg/kg, i.p) was administered to construct a sepsis model. Additionally, RAW264.7 cells were treated with LPS with/without GSE/its main components (Rd and Re) to explain the mechanisms corresponding to the animal-derived effects. LPS injection led to the death of all mice within 38 h, while GSE pretreatment delayed the time to death. GSE pretreatment also notably ameliorated LPS-induced systemic inflammation such as histological destruction in both the lung and liver, along with reductions in inflammatory cytokines, such as TNF-α, IL-6, and IL-1β, in both tissues and serum. Additionally, GSE markedly diminished the drastic secretion of nitric oxide (NO) by suppressing the expression levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX2) in both tissues. Similar changes in TNF-α, IL-1β, NO, iNOS, and COX2 were observed in LPS-stimulated RAW264.7 cells, and protein expression data and nuclear translocation assays suggested GSE could modulate LPS-binding protein (LBP), Toll-like receptor 4 (TLR4), and NF-κB. Ginsenoside Rd could be a major active component in GSE that produces the anti-sepsis effects. Our data support that ginseng sprouts could be used as an herbal resource to reduce the risk of sepsis. The corresponding mechanisms may involve TLR4/NF-κB signaling and a potentially active component.

Ginsenoside Rd ameliorates muscle wasting by suppressing the signal transducer and activator of transcription 3 pathway

BACKGROUND

The effects of some drugs, aging, cancers, and other diseases can cause muscle wasting. Currently, there are no effective drugs for treating muscle wasting. In this study, the effects of ginsenoside Rd (GRd) on muscle wasting were studied.

METHODS

Tumour necrosis factor-alpha (TNF-α)/interferon-gamma (IFN-γ)-induced myotube atrophy in mouse C2C12 and human skeletal myoblasts (HSkM) was evaluated based on cell thickness. Atrophy-related signalling, reactive oxygen species (ROS) level, mitochondrial membrane potential, and mitochondrial number were assessed. GRd (10 mg/kg body weight) was orally administered to aged mice (23-24 months old) and tumour-bearing (Lewis lung carcinoma [LLC1] or CT26) mice for 5 weeks and 16 days, respectively. Body weight, grip strength, inverted hanging time, and muscle weight were assessed. Histological analysis was also performed to assess the effects of GRd. The evolutionary chemical binding similarity (ECBS) approach, molecular docking, Biacore assay, and signal transducer and activator of transcription (STAT) 3 reporter assay were used to identify targets of GRd.

RESULTS

GRd significantly induced hypertrophy in the C2C12 and HSkM myotubes (average diameter 50.8 ± 2.6% and 49.9% ± 3.7% higher at 100 nM, vs. control, P ≤ 0.001). GRd treatment ameliorated aging- and cancer-induced (LLC1 or CT26) muscle atrophy in mice, which was evidenced by significant increases in grip strength, hanging time, muscle mass, and muscle tissue cross-sectional area (1.3-fold to 4.6-fold, vs. vehicle, P ≤ 0.05; P ≤ 0.01; P ≤ 0.001). STAT3 was found to be a possible target of GRd by the ECBS approach and molecular docking assay. Validation of direct interaction between GRd and STAT3 was confirmed through Biacore analysis. GRd also inhibited STAT3 phosphorylation and STAT3 reporter activity, which led to the inhibition of STAT3 nuclear translocation and the suppression of downstream targets of STAT3, such as atrogin-1, muscle-specific RING finger protein (MuRF-1), and myostatin (MSTN) (29.0 ± 11.2% to 84.3 ± 30.5%, vs. vehicle, P ≤ 0.05; P ≤ 0.01; P ≤ 0.001). Additionally, GRd scavenged ROS (91.7 ± 1.4% reduction at 1 nM, vs. vehicle, P ≤ 0.001), inhibited TNF-α-induced dysregulation of ROS level, and improved mitochondrial integrity (P ≤ 0.05; P ≤ 0.01; P ≤ 0.001).

CONCLUSIONS

GRd ameliorates aging- and cancer-induced muscle wasting. Our findings suggest that GRd may be a novel therapeutic agent or adjuvant for reversing muscle wasting.

Effect of steam-processing of the Panax ginseng root on its inducible activity on granulocyte-colony stimulating factor secretion in intestinal epithelial cells in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Panax ginseng root has been used as tonic in traditional Chinese medicine (TCM) and traditional Japanese Kampo medicine. Steam processing of Panax ginseng root is carried out to enhance its nourishing effects on qi.

AIM OF THE STUDY

In order to explore the mechanism of these beneficial effects behind the steam processing of the P. ginseng root, we evaluated effectiveness of processing on the granulocyte-colony stimulating factor (G-CSF) secretion in intestinal epithelial cell-like MCE301 cells.

MATERIALS AND METHODS

We collected P. ginseng root samples in the markets of China and Japan. Fresh or dried samples were steamed for different time lengths and subsequently dried and extracted. MCE301 cells were incubated with the medium containing various P. ginseng root extracts, while the concentration of G-CSF in the medium was measured. We also investigated the active ingredients by size exclusion HPLC.

RESULTS

The extracts of fresh P. ginseng hairy root samples steamed for more than 6 h significantly induced G-CSF secretion, and the maximum activity was recorded at a 9-h steaming. The same activity was noted when already dried P. ginseng hairy root samples were steamed. The extracts of fresh P. ginseng hairy root without steam processing and those of fresh P. ginseng root body samples with steam processing exhibited no activities. The active ingredients of steamed P. ginseng hairy root samples were high-molecular-weight compounds with an average molecular weight of 758 kDa, and the activity was mediated by the toll-like receptor (TLR) 9.

CONCLUSIONS

Our results shed on more light on the mechanism underlying the appearance of immunostimulatory activity of the P. ginseng hairy root induced by steam processing.

Antidepressant-Like Effect and Mechanism of Ginsenoside Rd on Rodent Models of Depression

Background

There is growing evidence to suggest that ginsenoside Rd (GRd) has a therapeutic effect on depression, but the specific mechanisms behind its activity require further study.

Objective

This study is designed to investigate the antidepressant-like effect and underlying mechanisms of GRd.

Methods

In this study, the behavioral despair mouse model of depression and chronic unpredictable mild stress (CUMS) rat model of depression were established to explore the effects of GRd on depression-like behavior and its underlying mechanisms. Behavioral tests were used to evaluate the replication of animal models and depression-like behaviors. The hypoxia-inducible factor-1α (HIF-1α) blocker 2-methoxyestradiol (2-ME) was injected to determine the role of HIF-1α in the antidepressant-like effect of GRd. In addition, molecular biology techniques were used to determine the mRNA and protein expression of HIF-1ɑ signaling pathway and synaptic plasticity-related regulators, that is synapsin 1 (SYN 1) and postsynaptic density protein 95 (PSD 95). In silico binding interaction studies of GRd with focused target proteins were performed using molecular docking to predict the affinity and optimal binding mode between ligands and receptors.

Results

Our data show that GRd significantly reversed depression-like behavior and promoted mRNA and protein expression of HIF-1ɑ signaling pathway and synaptic plasticity-related regulators. However, the antidepressant-like effect of GRd disappeared upon inhibition of HIF-1α expression following administration of 2-ME. Furthermore, molecular docking results showed that GRd possessed significant binding affinity for HIF-1α, VEGF, and VEGFR-2.

Conclusion

Our results show that GRd exhibits significant antidepressant-like effect and that HIF-1α signaling pathway is a promising target for the treatment of depression.

[Quality evaluation of ginsenoside reference substances based on qNMR spectroscopy]

The present study established a quality evaluation method for ginsenoside reference substances based on quantitative nuclear magnetic resonance(qNMR) spectroscopy. ~1H-NMR spectra were collected on Bruker Avance Ⅲ 500 MHz NMR spectrometer equipped with a 5 mm BBO probe. The acquire parameters were set up as follows: pulse sequence of 30°, D_1=20 s, probe temperature= 303 K, and the scan number = 32. Dimethyl terephthalate, a high-quality ~1H-qNMR standard, was used as the internal standard and measured by the absolute quantitative method. Methyl peaks of comparatively good sensitivity were selected for quantification, and linear fitting deconvolution was adopted to improve the accuracy of integration results. The qNMR spectroscopy-based method was established and validated, which was then used for the quality evaluation of ginsenoside Rg_1, ginsenoside Re, ginsenoside Rb_1, ginsenoside Rd, and notoginsenoside R_1. The results suggested that the content of these ginsenoside reference standards obtained from the qNMR spectroscopy-based method was lower than that detected by the normalization method in HPLC provided by the manufacturers. In conclusion, the qNMR spectroscopy-based method can ensure the quality of ginsenoside reference substances and provide powerful support for the accurate quality evaluation of Chinese medicine and its preparations. The qNMR spectroscopy-based method is simple, rapid, and accurate, which can be developed for the quantitative assay of Chinese medicine standard references.

Ginsenoside Rd Inhibits Glioblastoma Cell Proliferation by Up-Regulating the Expression of miR-144-5p

miR-144-5p exhibits anti-tumor activities in various cancers. Although treatment for glioblastoma has progressed rapidly, novel targets for glioblastoma are insufficient, particularly those used in precision medicine. In the current study, we found that ginsenoside Rd reduced the proliferation and migration of glioblastoma cells. Ginsenoside Rd up-regulated the tumor-suppressive miR-144-5p in glioblastoma cells. Moreover, Toll-like receptor 2, which is a target of miR-144-5p, was down-regulated. After inhibition of miR-144-5p, the effect of Ginsenoside Rd on proliferation inhibition and down-regulation of Toll-like receptor 2 was reduced. These data demonstrated the ginsenoside Rd/miR-144-5p/Toll-like receptor 2 regulatory nexus that controls the glioblastoma pathogenesis of glioblastoma. Our work provided novel targets for glioblastoma diagnosis and treatment.

Two Key Amino Acids Variant of α-l-arabinofuranosidase from Bacillus subtilis Str. 168 with Altered Activity for Selective Conversion Ginsenoside Rc to Rd

α-l-arabinofuranosidase is a subfamily of glycosidases involved in the hydrolysis of l-arabinofuranosidic bonds, especially in those of the terminal non-reducing arabinofuranosyl residues of glycosides, from which efficient glycoside hydrolases can be screened for the transformation of ginsenosides. In this study, the ginsenoside Rc-hydrolyzing α-l-arabinofuranosidase gene, BsAbfA, was cloned from Bacilus subtilis, and its codons were optimized for efficient expression in E. coli BL21 (DE3). The recombinant protein BsAbfA fused with an N-terminal His-tag was overexpressed and purified, and then subjected to enzymatic characterization. Site-directed mutagenesis of BsAbfA was performed to verify the catalytic site, and the molecular mechanism of BsAbfA catalyzing ginsenoside Rc was analyzed by molecular docking, using the homology model of sequence alignment with other β-glycosidases. The results show that the purified BsAbfA had a specific activity of 32.6 U/mg. Under optimal conditions (pH 5, 40 °C), the kinetic parameters K_m of BsAbfA for pNP-α-Araf and ginsenoside Rc were 0.6 mM and 0.4 mM, while the K_cat/K_m were 181.5 s^-1 mM^-1 and 197.8 s^-1 mM^-1, respectively. More than 90% of ginsenoside Rc could be transformed by 12 U/mL purified BsAbfA at 40 °C and pH 5 in 24 h. The results of molecular docking and site-directed mutagenesis suggested that the E173 and E292 variants for BsAbfA are important in recognizing ginsenoside Rc effectively, and to make it enter the active pocket to hydrolyze the outer arabinofuranosyl moieties at C₂₀ position. These remarkable properties and the catalytic mechanism of BsAbfA provide a good alternative for the effective biotransformation of the major ginsenoside Rc into Rd.

One-Pot Process for the Production of Ginsenoside Rd by Coupling Enzyme-Assisted Extraction with Selective Enzymolysis

One-pot process for the production of ginsenoside Rd by coupling enzyme-assisted extraction with selective enzymolysis was explored in this paper. Several detection methods including HPLC-MS were used to identify and quantify the products in the enzymolysis solution of pectinase. Results showed that ginsenoside Rd was the main component in enzymolysis solution, pectinase specifically hydrolyzes protopanaxadiol (PPD)-type ginsenoside and was a selective enzyme to convert ginsenoside Rb1 to Rd in a way. In addition the influencing factors on the yield of ginsenoside Rb1 and Rd were optimized using L₉(3⁴) orthogonal design data. The enzymolysis conditions for the higher yield of Rd were 52.5 °C, pH 6 and 1 h with a yield of 0.8314 from 50 mg drug material. The controllable transformation hypothesis of the PPD-type ginsenoside was also explored from the perspective of the molecular steric hindrance. Pectinase could be used as an efficient enzyme for one-pot producing ginsenoside Rd.

Ginsenoside Rd Ameliorates Auditory Cortex Injury Associated With Military Aviation Noise-Induced Hearing Loss by Activating SIRT1/PGC-1α Signaling Pathway

Free radicals and oxidative stress play an important role in the pathogenesis of noise-induced hearing loss (NIHL). Some ginseng monomers showed certain therapeutic effects in NIHL by scavenging free radicals. Therefore, we hypothesized that ginsenoside Rd (GSRd) may exert neuroprotective effects after noise-induced auditory system damage through a mechanism involving the SIRT1/PGC-1α signaling pathway. Forty-eight guinea pigs were randomly divided into four equal groups (normal control group, noise group, experimental group that received GSRd dissolved in glycerin through an intraperitoneal injection at a dose of 30 mg/kg body weight from 5 days before noise exposure until the end of the noise exposure period, and experimental control group). Hearing levels were examined by auditory brainstem response (ABR) and distortion product otoacoustic emission (DPOAE). Hematoxylin-eosin and Nissl staining were used to examine neuron morphology. RT-qPCR and western blotting analysis were used to examine SIRT1/PGC-1α signaling and apoptosis-related genes, including Bax and Bcl-2, in the auditory cortex. Bax and Bcl-2 expression was assessed via immunohistochemistry analysis. Superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione peroxidase (GSH-Px) levels were determined using a commercial testing kit. Noise exposure was found to up-regulate ABR threshold and down-regulate DPOAE amplitudes, with prominent morphologic changes and apoptosis of the auditory cortex neurons (p < 0.01). GSRd treatment restored hearing loss and remarkably alleviated morphological changes or apoptosis (p < 0.01), concomitantly increasing Bcl-2 expression and decreasing Bax expression (p < 0.05). Moreover, GSRd increased SOD and GSH-Px levels and decreased MDA levels, which alleviated oxidative stress damage and activated SIRT1/PGC-1α signaling pathway. Taken together, our findings suggest that GSRd ameliorates auditory cortex injury associated with military aviation NIHL by activating the SIRT1/PGC-1α signaling pathway, which can be an attractive pharmacological target for the development of novel drugs for NIHL treatment.

Ginsenoside Rd therapy improves histological and functional recovery in a rat model of inflammatory bowel disease

Ginsenoside Rd (GRd) is a biologically active component of ginseng that stimulates the proliferation of endogenous stem cells. The objective of our research was to evaluate the utility of GRd in gastrointestinal mucosal regeneration in a rat model of inflammatory bowel disease (IBD) and to clarify whether GRd exerts its pharmacological effects by modulating endogenous intestinal stem cells. The IBD rat model was established via subcutaneous injection of indomethacin, and 10, 20, or 40 mg/kg GRd or an equal volume of physiological saline was then administered orally to rats in different groups every day for seven consecutive days. We observed that GRd treatment, especially 20 mg/kg GRd, significantly reduced indomethacin-induced damage compared with that in the control group. By measuring the mRNA and protein levels of the intestinal stem cell markers Bmi and Msi-1 and the intestinal epithelial cell marker CDX-2 as well as by double-labelling these markers with 5-bromo-2-deoxyuridine (BrdU), we inferred that GRd could stimulate the proliferation and differentiation of endogenous intestinal stem cells in IBD model rats, leading to improved recovery of intestinal function.

Enzymatic Biotransformation of Ginsenoside Rb2 into Rd by Recombinant α-L-Arabinopyranosidase from Blastococcus saxobsidens

In this study, we used a novel α-L-arabinopyranosidase (AbpBs) obtained from ginsenoside-converting Blastococcus saxobsidens that was cloned and expressed in Escherichia coli BL21 (DE3), and then applied it in the biotransformation of ginsenoside Rb₂ into Rd. The gene, termed AbpBs, consisting of 2,406 nucleotides (801 amino acid residues), and with a predicted translated protein molecular mass of 86.4 kDa, was cloned into a pGEX4T-1 vector. A BLAST search using the AbpBs amino acid sequence revealed significant homology with a family 2 glycoside hydrolase (GH2). The over-expressed recombinant AbpBs in Escherichia coli BL21 (DE3) catalyzed the hydrolysis of the arabinopyranose moiety attached to the C-20 position of ginsenoside Rb2 under optimal conditions (pH 7.0 and 40°;C). Kinetic parameters for α-Larabinopyranosidase showed apparent K_m and V_max values of 0.078 ± 0.0002 micrometer and 1.4 ± 0.1 μmol/min/mg of protein against p-nitrophenyl-α-L-arabinopyranoside. Using a purified AbpBs (1 μg/ml), 0.1% of ginsenoside Rb₂ was completely converted to ginsenoside Rd within 1 h. The recombinant AbpBs could be useful for high-yield, rapid, and low-cost preparation of ginsenoside Rd from Rb₂.

Bifidobacteria-Fermented Red Ginseng and Its Constituents Ginsenoside Rd and Protopanaxatriol Alleviate Anxiety/Depression in Mice by the Amelioration of Gut Dysbiosis

Gut dysbiosis is closely connected with the outbreak of psychiatric disorders with colitis. Bifidobacteria-fermented red ginseng (fRG) increases the absorption of ginsenoside Rd and protopanxatriol into the blood in volunteers and mice. fRG and Rd alleviates 2,4,6-trinitrobenzenesulfonic acid-induced colitis in mice. Therefore, to understand the gut microbiota-mediated mechanism of fRG against anxiety/depression, we examined the effects of red ginseng (RG), fRG, ginsenoside Rd, and protopanaxatriol on the occurrence of anxiety/depression, colitis, and gut dysbiosis in mice. Mice with anxiety/depression were prepared by being exposed to two stressors, immobilization stress (IS) or Escherichia coli (EC). Treatment with RG and fRG significantly mitigated the stress-induced anxiety/depression-like behaviors in elevated plus maze, light-dark transition, forced swimming (FST), and tail suspension tasks (TST) and reduced corticosterone levels in the blood. Their treatments also suppressed the stress-induced NF-κB activation and NF-κB+/Iba1+ cell population in the hippocampus, while the brain-derived neurotrophic factor (BDNF) expression and BDNF+/NeuN+ cell population were increased. Furthermore, treatment with RG or fRG suppressed the stress-induced colitis: they suppressed myeloperoxidase activity, NF-κB activation, and NF-κB+/CD11c+ cell population in the colon. In particular, fRG suppressed the EC-induced depression-like behaviors in FST and TST and colitis more strongly than RG. fRG treatment also significantly alleviated the EC-induced NF-κB+/Iba1+ cell population and EC-suppressed BDNF+/NeuN+ cell population in the hippocampus more strongly than RG. RG and fRG alleviated EC-induced gut dysbiosis: they increased Bacteroidetes population and decreased Proteobacteria population. Rd and protopanaxatriol also alleviated EC-induced anxiety/depression and colitis. In conclusion, fRG and its constituents Rd and protopanaxatriol mitigated anxiety/depression and colitis by regulating NF-κB-mediated BDNF expression and gut dysbiosis.

Ginsenoside Rd Inhibits the Metastasis of Colorectal Cancer via Epidermal Growth Factor Receptor Signaling Axis

Ginsenoside Rd is a saponin from ginseng and has been reported to have various biological activities. However, the effect of ginsenoside Rd on the metastasis of colorectal cancer (CRC) remains unknown. Here, we found that ginsenoside Rd decreased the colony-forming ability, migration, invasion, and wound-healing abilities of CRC cells, although it did not affect cell proliferation. In addition, using an inverse-docking assay, we found that ginsenoside Rd bound to epidermal growth factor receptor (EGFR) with a high binding affinity, inducing the downregulation of stemness- and epithelial-mesenchymal transition-related genes; these were partially rescued by either exogenous EGF treatment or ectopic expression of SOX2. Furthermore, ginsenoside Rd significantly decreased the number and size of tumor metastasis nodules in the livers, lungs, and kidneys of mouse model of metastasis. © 2018 IUBMB Life, 71(5):601-610, 2019.

The inhibitory effects of ginsenoside Rd on the human glioma U251 cells and its underlying mechanisms

OBJECTIVE

The current study was designed to investigate the inhibitory effects of ginsenoside Rd (Gs-Rd) on human glioma U251 cells in vitro and its possible underlying mechanisms.

METHODS

The groups included blank control group, low concentration Gs-Rd treatment group (20 μM), mid concentration Gs-Rd treatment group (40 μM), and high concentration Gs-Rd treatment group (80 μM). The proliferative activity of human glioma U251 cells was detected by the MTT assay. Flow cytometry was performed to measure cell apoptosis of human glioma U251 cells. In addition, the ELISA assay was used to measure the telomerase activities in different groups on 24 hours, 48 hours, and 72 hours. Furthermore, real-time quantitative polymerase chain reaction (RT-PCR) and Western blot analysis were performed to measure the expression of Bcl-2, human telomerase catalytic subunit (hTERT), and caspase-3 in different groups on 48 hours at both messenger RNA (mRNA) and protein levels.

RESULTS

The proliferation of U251 cells was inhibited by Gs-Rd with different concentrations in the dose- and time-dependent manners. In addition, Gs-Rd promoted U251 cell apoptosis rate in a dose-dependent manner. Gs-Rd with different concentrations (20 μM, 40 μM, and 80 μM) significantly enhanced the expression of teleomerase on 24 hours and 48 hours. In addition, Gs-Rd with different concentrations significantly increased caspase-3 and decreased Bcl-2 and hTERT expressions at both mRNA and protein levels.

CONCLUSION

The Gs-Rd can remarkably inhibit the proliferation and promote cell apoptosis of human glioma U251 cells. The possible underlying mechanisms could be related to inhibiting telomerase activity, downregulating expression of Bcl-2 and hTERT, and upregulating expression of caspase-3 of human glioma U251 cells.

Ginsenoside Rd as a potential neuroprotective agent prevents trimethyltin injury

Trimethyltin (TMT) is a potent neurotoxicant that affects various regions within the central nervous system, including the neocortex, cerebellum, and hippocampus. In the present study, ginsenoside Rd was investigated as a candidate neuroprotective agent in a primary hippocampal neuron culture and mouse models. TMT induced neurotoxicity in a seven-day primary hippocampal neuron culture in a dose-dependent manner (2.5-10 µM). However, pre-treatment with 20 µg/ml ginsenoside Rd for 24 h reversed the toxic action. ICR mice were administered a single injection of 2 mg/kg body weight TMT. Apparent tremor seizure and impaired passive avoidance tests demonstrated significant differences when compared with a saline treated control group. Nissl staining was performed to evaluate the neuronal loss in the hippocampus. In addition, immunostaining of glial fibrillary acidic protein characterized the features of astroglial activation. These results demonstrated that TMT markedly induced Cornu Ammonis 1 subregion neuronal loss and reactive astrocytes in the hippocampus, indicating disrupted hippocampal function. Notably, ginsenoside Rd attenuated the tremor seizures and cognitive decline in behavioral tests. Additionally, significantly reduced neuronal loss (P=0.018) and active astroglials (P=0.003) were observed in the ginsenoside Rd treated group. Ginsenoside Rd prevented TMT-induced cell apoptosis via regulation of B-cell lymphoma 2 (Bcl-2), bcl-2-like protein 4 and caspase-3. These results demonstrate that ginsenoside may be developed as a neuroprotective agent to prevent TMT-induced neurotoxicity.

Endothelium-dependent vasodilation effects of Panax notoginseng and its main components are mediated by nitric oxide and cyclooxygenase pathways

Panax notoginseng, a traditional Chinese herbal medicine, has been used for the treatment of cardiovascular diseases. The main bioactive components of this species are Panax notoginseng saponins (PNS). The present study aimed to investigate the effects of PNS and five of its main components (ginsenosides Rg1, Re, Rb1 and Rd, and notoginsenoside R1) on rat aorta rings pre-contracted with norepinephrine (NE) and to determine the underlying mechanism of action. Isolated aorta rings (with or without intact endothelium) from adult male Wistar rats were stimulated with NE to induce vasoconstriction, and subsequently treated with different concentrations of PNS and its five main components (Rg1, Re, Rb1, R1 and Rd) separately. This procedure was repeated after pre-incubation with the nitric oxide (NO) synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME), the guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) and the cyclooxygenase (COX) inhibitor indomethacin (INDO), in order to elucidate the mechanism of action of PNS and its components. The results demonstrated that PNS and the components Rg1, Re, Rb1 and R1, but not Rd, induced vessel relaxation in a concentration-dependent manner when the endothelium lining was intact. NO synthase inhibitor L-NAME and guanylate cyclase inhibitor ODQ attenuated the diastolic effects of PNS, Rg1, Re, Rb1 and R1 in aortic rings with intact endothelium. By contrast, INDO, a known COX inhibitor weakened the vasodilation effects of PNS, Re and Rb1 but demonstrated no effect on Rg1 and R1. In conclusion, PNS and two of its main components (Re and Rb1) exert vasodilating effects through the NO and COX pathways.

Ginsenoside-Rd Promotes Neurite Outgrowth of PC12 Cells through MAPK/ERK- and PI3K/AKT-Dependent Pathways

Panax ginseng is a famous herbal medicine widely used in Asia. Ginsenosides have been identified as the principle active ingredients for Panax ginseng’s biological activity, among which ginsenoside Rd (Rd) attracts extensive attention for its obvious neuroprotective activities. Here we investigated the effect of Rd on neurite outgrowth, a crucial process associated with neuronal repair. PC12 cells, which respond to nerve growth factor (NGF) and serve as a model for neuronal cells, were treated with different concentrations of Rd, and then their neurite outgrowth was evaluated. Our results showed that 10 μM Rd significantly increased the percentages of long neurite- and branching neurite-bearing cells, compared with respective controls. The length of the longest neurites and the total length of neurites in Rd-treated PC12 cells were much longer than that of respective controls. We also showed that Rd activated ERK1/2 and AKT but not PKC signalings, and inhibition of ERK1/2 by PD98059 or/and AKT by LY294002 effectively attenuated Rd-induced neurite outgrowth. Moreover, Rd upregulated the expression of GAP-43, a neuron-specific protein involved in neurite outgrowth, while PD98059 or/and LY294002 decreased Rd-induced increased GAP-43 expression. Taken together, our results provided the first evidence that Rd may promote the neurite outgrowth of PC12 cells by upregulating GAP-43 expression via ERK- and ARK-dependent signaling pathways.

Ginsenoside Rd alleviates mouse acute renal ischemia/reperfusion injury by modulating macrophage phenotype

Background

Ginsenoside Rd (GSRd), a main component of the root of Panax ginseng, exhibits anti-inflammation functions and decreases infarct size in many injuries and ischemia diseases such as focal cerebral ischemia. M1 Macrophages are regarded as one of the key inflammatory cells having functions for disease progression.

Methods

To investigate the effect of GSRd on renal ischemia/reperfusion injury (IRI) and macrophage functional status, and their regulatory role on mouse polarized macrophages in vitro, GSRd (10–100 mg/kg) and vehicle were applied to mice 30 min before renal IRI modeling. Renal functions were reflected by blood serum creatinine and blood urea nitrogen level and histopathological examination. M1 polarized macrophages infiltration was identified by flow cytometry analysis and immunofluorescence staining with CD11b⁺, iNOS⁺/interleukin-12/tumor necrosis factor-α labeling. For the in vitro study, GSRd (10–100 μg/mL) and vehicle were added in the culture medium of M1 macrophages to assess their regulatory function on polarization phenotype.

Results

In vivo data showed a protective role of GSRd at 50 mg/kg on Day 3. Serum level of serum creatinine and blood urea nitrogen significantly dropped compared with other groups. Reduced renal tissue damage and M1 macrophage infiltration showed on hematoxylin–eosin staining and flow cytometry and immunofluorescence staining confirmed this improvement. With GSRd administration, in vitro cultured M1 macrophages secreted less inflammatory cytokines such as interleukin-12 and tumor necrosis factor-α. Furthermore, macrophage polarization-related pancake-like morphology gradually changed along with increasing concentration of GSRd in the medium.

Conclusion

These findings demonstrate that GSRd possess a protective function against renal ischemia/reperfusion injury via downregulating M1 macrophage polarization.

Ginsenoside Rd and ischemic stroke; a short review of literatures

Panax ginseng is a well-known economic medical plant that is widely used in Chinese traditional medicine. This species contains a unique class of natural products-ginsenosides. Recent clinical and experimental studies have presented numerous lines of evidence on the promising role of ginsenosides on different diseases including neurodegenerative diseases, cardiovascular diseases, and certain types of cancer. Nowadays, most of the attention has focused on ginsenoside Rd as a neuroprotective agent to attenuate ischemic stroke damages. Some of the evidence showed that ginsenoside Rd ameliorates ischemic stroke-induced damages through the suppression of oxidative stress and inflammation. Ginsenoside Rd can prolong neural cells' survival through the upregulation of the endogenous antioxidant system, phosphoinositide-3-kinase/AKT and extracellular signal-regulated protein kinase 1/2 pathways, preservation of mitochondrial membrane potential, suppression of the nuclear factor-kappa B, transient receptor potential melastatin, acid sensing ion channels 1a, poly(ADP-ribose) polymerase-1, protein tyrosine kinase activation, as well as reduction of cytochrome c-releasing and apoptosis-inducing factor. In the current work, we review the available reports on the promising role of ginsenoside Rd on ischemic stroke. We also discuss its chemistry, source, and the molecular mechanism underlying this effect.

Ginsenoside Rd Protects SH-SY5Y Cells against 1-Methyl-4-phenylpyridinium Induced Injury

Ginsenoside Rd (GSRd), one of the main active monomer compounds from the medical plant Panaxginseng, has been shown to promote neuronal survival in models of ischemic cerebral damage. As an extending study, here we examined whether GSRd could exert a beneficial effect in an experimental Parkinson disease (PD) model in vitro, in which SH-SY5Y cells were injured by 1-methyl-4-phenylpyridinium (MPP⁺), an active metabolic product of the classical Parkinsonian toxin1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Our results, from the addition of different concentrations of GSRd (1, 10 and 50 μM), showed that GSRd at 1 and 10 μM could significantly attenuate MPP⁺-induced cell death. This protective effect may be ascribed to its ability to reduce intracellular reactive oxygen species levels, enhance antioxidant enzymatic activities, preserve the activity of respiratory complex I, stabilize the mitochondrial membrane potential and increase intracellular ATP levels. Additionally, the PI3K/Akt survival-signaling pathway was also involved in the protective effect of GSRd. Finally, using a mouse PD model in vivo, we also found that GSRd obviously reversed the loss of tyrosine hydroxylase-positive cells in substanitia nigra induced by MPTP. Thus, our findings demonstrated that GSRd showed a significant neuro-protective effect against experimental PD models, which may involve its antioxidant effects and mitochondrial function preservation.

Inhibition of L-type Ca(2+) current by ginsenoside Rd in rat ventricular myocytes

Background

Ginsenoside Rd (GSRd), one of the most abundant ingredients of Panax ginseng, protects the heart via multiple mechanisms including the inhibition of Ca²⁺ influx. We intended to explore the effects of GSRd on L-type Ca²⁺ current (I_Ca,L) and define the mechanism of the suppression of I_Ca,L by GSRd.

Methods

Perforated-patch recording and whole-cell voltage clamp techniques were applied in isolated rat ventricular myocytes.

Results

(1) GSRd reduced I_Ca,L peak amplitude in a concentration-dependent manner [half-maximal inhibitory concentration (IC₅₀) = 32.4 ± 7.1 μmol/L] and up-shifted the current–voltage (I–V) curve. (2) GSRd (30 μmol/L) significantly changed the steady-state activation curve of I_Ca,L (V_0.5: −19.12 ± 0.68 vs. −16.26 ± 0.38 mV; n = 5, p < 0.05) and slowed down the recovery of I_Ca,L from inactivation [the time content (ζ) from 91 ms to 136 ms, n = 5, p < 0.01]. (3) A more significant inhibitive effect of GSRd (100 μmol/L) was identified in perforated-patch recording when compared with whole-cell recording [65.7 ± 3.2% (n = 10) vs. 31.4 ± 5.2% (n = 5), p < 0.01]. (4) Pertussis toxin (G_iprotein inhibitor) completely abolished the I_Ca,L inhibition induced by GSRd. There was a significant difference in inhibition potency between the two cyclic adenosine monophosphate elevating agents (isoprenaline and forskolin) prestimulation [55 ± 7.8% (n = 5) vs. 17.2 ± 3.5% (n = 5), p < 0.01]. (5) 1H-[1,2,4]Oxadiazolo[4,3-a]-quinoxalin-1-one (a guanylate cyclase inhibitor) and N-acetyl-l-cysteine (a nitric oxide scavenger) partly recovered the I_Ca,L inhibition induced by GSRd. (6) Phorbol-12-myristate-13-acetate (a protein kinase C activator) and GF109203X (a protein kinase C inhibitor) did not contribute to the inhibition of GSRd.

Conclusion

These findings suggest that GSRd could inhibit I_Ca,L through pertussis toxin-sensitive G protein (G_i) and a nitric oxide–cyclic guanosine monophosphate-dependent mechanism.

Ginsenoside Rd inhibits apoptosis following spinal cord ischemia/reperfusion injury

Ginsenoside Rd has a clear neuroprotective effect against ischemic stroke. We aimed to verify the neuroprotective effect of ginsenoside Rd in spinal cord ischemia/reperfusion injury and explore its anti-apoptotic mechanisms. We established a spinal cord ischemia/reperfusion injury model in rats through the occlusion of the abdominal aorta below the level of the renal artery for 1 hour. Successfully established models were injected intraperitoneally with 6.25, 12.5, 25 or 50 mg/kg per day ginsenoside Rd. Spinal cord morphology was observed at 1, 3, 5 and 7 days after spinal cord ischemia/reperfusion injury. Intraperitoneal injection of ginsenoside Rd in ischemia/reperfusion injury rats not only improved hindlimb motor function and the morphology of motor neurons in the anterior horn of the spinal cord, but it also reduced neuronal apoptosis. The optimal dose of ginsenoside Rd was 25 mg/kg per day and the optimal time point was 5 days after ischemia/reperfusion. Immunohistochemistry and western blot analysis showed ginsenoside Rd dose-dependently inhibited expression of pro-apoptotic Caspase 3 and down-regulated the expression of the apoptotic proteins ASK1 and JNK in the spinal cord of rats with spinal cord ischemia/reperfusion injury. These findings indicate that ginsenoside Rd exerts neuroprotective effects against spinal cord ischemia/reperfusion injury and the underlying mechanisms are achieved through the inhibition of ASK1-JNK pathway and the down-regulation of Caspase 3 expression.

Effect of a soluble prebiotic fiber, NUTRIOSE, on the absorption of ginsenoside Rd in rats orally administered ginseng

Background

There is limited understanding of the effect of dietary components on the absorption of ginsenosides and their metabolites into the blood.

Methods

This study investigated the pharmacokinetics of the ginseng extract and its main constituent ginsenoside Rb1 in rats with or without pretreatment with a prebiotic fiber, NUTRIOSE, by liquid chromatography tandem mass spectrometry. When ginsenoside Rb1 was incubated with rat feces, its main metabolite was ginsenoside Rd.

Results

When the intestinal microbiota of rat feces were cultured in vitro, their ginsenoside Rd-forming activities were significantly induced by NUTRIOSE. When ginsenoside Rb1 was orally administered to rats, the maximum plasma concentration (Cmax) and area under the plasma drug concentration–time curve (AUC) for the main metabolite, ginsenoside Rd, were 72.4 ± 31.6 ng/mL and 663.9 ± 285.3 μg·h/mL, respectively. When the ginseng extract (2,000 mg/kg) was orally administered, Cmax and AUC for ginsenoside Rd were 906.5 ± 330.2 ng/mL and 11,377.3 ± 4,470.2 μg·h/mL, respectively. When ginseng extract was orally administered to rats fed NUTRIOSE containing diets (2.5%, 5%, or 10%), Cmax and AUC were increased in the NUTRIOSE receiving groups in a dose-dependent manner.

Conclusion

These findings reveal that intestinal microflora promote metabolic conversion of ginsenoside Rb1 and ginseng extract to ginsenoside Rd and promote its absorption into the blood in rats. Its conversion may be induced by prebiotic diets such as NUTRIOSE.

Ginsenoside Rd promotes glutamate clearance by up-regulating glial glutamate transporter GLT-1 via PI3K/AKT and ERK1/2 pathways

Ginsenoside Rd (Rd), one of the main active ingredients in Panax ginseng, has been showed to protect against ischemic cerebral damage both in vitro and in vivo. However, the underlying mechanism of Rd is largely unknown. Excessive extracellular glutamate causes excitatory toxicity, leading to cell death, and neurodegenerative processes after brain ischemia. The clearance of extracellular glutamate by astrocytic glutamate transporter GLT-1 is essential for neuronal survival after stroke. Here we investigated the effects of Rd on the levels of extracellular glutamate and the expression of GLT-1 in vivo and in vitro. After rat middle cerebral artery occlusion, Rd significantly increased the mRNA and protein expression levels of GLT-1, and reduced the burst of glutamate as revealed by microdialysis. Consistently, specific glutamate uptake by cultured astrocytes was elevated after Rd exposure. Furthermore, we showed that Rd increased the levels of phosphorylated protein kinase B (PKB/Akt) and phospho-ERK1/2 (p-ERK1/2) in astrocyte culture after oxygen-glucose deprivation. Moreover, the effect of Rd on GLT-1 expression and glutamate uptake can be abolished by PI3K/AKT agonist LY294002 or ERK1/2 inhibitor PD98059. Taken together, our findings provide the first evidence that Rd can promote glutamate clearance by up-regulating GLT-1 expression through PI3K/AKT and ERK1/2 pathways.

Purification and characterization of a ginsenoside Rb(1)-hydrolyzing β-glucosidase from Aspergillus niger KCCM 11239

Rb(1)-hydrolyzing β-glucosidase from Aspergillus niger KCCM 11239 was studied to develop a bioconversion process for minor ginsenosides. The specific activity of the purified enzyme was 46.5 times greater than that of the crude enzyme. The molecular weight of the native enzyme was estimated to be approximately 123 kDa. The optimal pH of the purified enzyme was pH 4.0, and the enzyme proved highly stable over a pH range of 5.0-10.0. The optimal temperature was 70 °C, and the enzyme became unstable at temperatures above 60 °C. The enzyme was inhibited by Cu(2+), Mg(2+), Co(2+), and acetic acid (10 mM). In the specificity tests, the enzyme was found to be active against ginsenoside Rb(1), but showed very low levels of activity against Rb(2), Rc, Rd, Re, and Rg(1). The enzyme hydrolyzed the 20-C,β-(1→6)-glucoside of ginsenoside Rb(1) to generate ginsenoside Rd and Rg(3), and hydrolyzed 3-C,β-(1→2)-glucoside to generate F(2). The properties of the enzyme indicate that it could be a useful tool in biotransformation applications in the ginseng industry, as well as in the development of novel drug compounds.