Multi-layered effects of Panax notoginseng on immune system.

Recent research has demonstrated the immunomodulatory potential of Panax notoginseng in the treatment of chronic inflammatory diseases and cerebral hemorrhage, suggesting its significance in clinical practice. Nevertheless, the complex immune activity of various components has hindered a comprehensive understanding of the immune-regulating properties of Panax notoginseng, impeding its broader utilization. This review evaluates the effect of Panax notoginseng to various types of white blood cells, elucidates the underlying mechanisms, and compares the immunomodulatory effects of different Panax notoginseng active fractions, aiming to provide the theory basis for future immunomodulatory investigation.

Ginsenoside RD prevents acute liver injury in mice by inhibiting STAT3-mediated NLRP3/GSDMD activation.

We investigated the role and mechanism of ginsenoside RD (GRD) in acute liver injury. Network pharmacology was used to analyze the correlations among GRD-liver injury-pyroptosis targets. A mouse model of acute liver injury was established by lipopolysaccharide + d-galactose（LPS + d/Gal). After pretreatment with GRD, the changes in mouse liver function were detected. The histopathological changes were assayed by hematoxylin and eosin and Masson staining, the tissue expressions of inflammatory cytokines were detected by enzyme-linked immunosorbent assay, and the protein expressions were assayed by immunohistochemical staining and Western blotting. Meanwhile, mechanism research was conducted using STAT3-knockout transgenic mice and STAT3-IN13, a STAT3 inhibitor. GRD inhibited liver injury, mitigated tissue inflammation, and suppressed STAT3-mediated pyroptosis in mice. After applying STAT3-knockout mouse model or STAT3-IN13, GRD did not further inhibit the liver injury. GRD can resist liver injury by inhibiting the STAT3-mediated pyroptosis, which is one of the hepatoprotective mechanisms of GRD.

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-1ß, 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-1ß, 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 high glucose-induced retinal endothelial injury through AMPK-STRT1 interdependence.

Diabetic retinopathy (DR) manifests as a complicated and blinding complication in diabetes mellitus. First-line treatments for advanced DR have shown ocular side-effects in some patients. Ginsenoside Rd (Rd), an active ingredient isolated from Panax notoginseng and P. ginseng, has demonstrated diverse and powerful activities on neuroprotection, anticancer and anti-inflammation, but its vascular protective effects have rarely been reported. Herein, this study aims to investigate the protective effects of Rd on retinal endothelial injury with emphasis on AMPK/SIRT1 interaction. The results indicated that Rd promoted AMPK activation and SIRT1 expression. Besides, Rd strengthened the interaction between AMPK and SIRT1 by increasing NAD+/NADH levels and LKB1 deacetylation in endothelial cells. Moreover, Rd reversed high glucose-induced activation of NOX2, oxidative stress, mitochondrial dysfunction, and endothelial apoptosis in an AMPK/SIRT1-interdependent manner. Hyperglycemia induced loss of endothelial cells and other retinal damage, which was restored by Rd via activating AMPK and SIRT1 in vivo. The enhancement of AMPK/SIRT1 interaction by Rd beneficially modulated oxidative stress and apoptosis, and ameliorated diabetes-driven vascular damage. These data also supported the evidence for Rd clinical development of pharmacological interventions and provided a novel potential vascular protective drug for early DR.

Targeting Akt/CREB/BDNF signaling pathway by ginsenosides in neurodegenerative diseases: A mechanistic approach.

Neurodegenerative diseases (NDDs) are leading causes of death and morbidity in the elderly worldwide. From the mechanistic/pathological view, oxidative stress, inflammation, and apoptosis are responsible for the etiology of neuronal diseases, and play detrimental roles in neuronal cell death and neurodegenerative processes. The diverse pathophysiological pathways influencing NDDs necessitate the discovery of pivotal dysregulated signaling mediators. The current review describes essential functions of protein kinase B (Akt)/cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB)/brain-derived neurotrophic factor (BDNF) pathway as possible therapeutic targets in the pathogenesis of NDDs. Consequently, finding new multi-target agents in regulating Akt/CREB/BDNF and thus associated downstream pathways is a critical factor in combating NDDs. Because of their neuroprotective properties, dietary phytochemicals have shown to be popular nutritional therapy methods. Ginsenosides, the most active ingredient of ginseng, and a secondary metabolite of steroid glycosides and triterpene saponins have been found to have a number of protective effects on the central nervous system (CNS). The protective roles of ginsenosides in CNS are potentially passing through Akt/CREB/BDNF pathway towards neuroprotective responses. In the present study, Akt/CREB/BDNF pathway is targeted by ginsenosides and associated nanoformulations towards potential neuroprotective effects.

Enzymatic biotransformation of Rb3 from the leaves of Panax notoginseng to ginsenoside rd by a recombinant ß-xylosidase from Thermoascus aurantiacus.

Given the important pharmacological activity of ginsenoside Rd but its low content in plants, the production of Rd by enzymatic transformation is of interest. In this study, a ß-xylosidase gene Ta-XylQS from Thermoascus aurantiacus was cloned and overexpressed in Komagataella phaffii. Purified recombinant Ta-XylQS specifically hydrolyzes substrates with xylosyl residues at the optimal pH of 3.5 and temperature of 60 °C. This study established a process for producing Rd by transforming ginsenoside Rb3 in the saponins of Panax notoginseng leaves via recombinant Ta-XylQS. After 60 h, 3 g L- 1 of Rb3 was transformed into 1.46 g L- 1 of Rd, and the maximum yield of Rd reached 4.31 g kg- 1 of Panax notoginseng leaves. This study is the first report of the biotransformation of ginsenoside Rb3 to Rd via a ß-xylosidase, and the established process could potentially be adopted for the commercial production of Rd from Rb3.

[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.

Paenibacillus roseus sp. nov., a ginsenoside-transforming bacterium isolated from forest soil.

A novel, pink-pigmented, Gram-stain-positive, aerobic, motile, rod-shaped and ginsenoside-converting bacterium, designated strain MAHUQ-46T, was isolated from soil of a forest. Strain MAHUQ-46T grew in the pH range 6.0-9.0 (optimum, 7.5), at temperatures between 10 and 37 °C (optimum, 30 °C) and at 0-3% (w/v) NaCl (optimum, 0.5%). 16S rRNA gene sequence analysis showed that strain MAHUQ-46T was closely related to Paenibacillus pinihumi S23T (97.3% similarity), followed by Paenibacillus elymi KUDC6143T (96.7%). The draft genome of strain MAHUQ-46T had a total length of 5,367,904 base pairs. A total of 4,857 genes were identified, in which 4,629 were protein-coding genes and 137 were RNA genes. The genome annotation of MAHUQ-46T showed 172 carbohydrate genes, some of them may be responsible for the biosynthesis of ginsenoside Rd from major ginsenoside Rb1. The DNA G + C content was 48.4 mol% and the major quinone was MK-7. Main fatty acids of strain MAHUQ-46T were C15: 0 anteiso, C16: 0 and C17: 0 anteiso. The polar lipids comprised phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidyl-N-methylethanolamine, two unidentified aminophospholipids and five unidentified phospholipids. Diagnostic diamino acid of peptidoglycan was meso-diaminopimelic acid. The novel strain MAHUQ-46T was able to rapidly synthesize ginsenoside Rd from major ginsenoside Rb1. The synthesized ginsenoside was confirmed by TLC and HPLC analysis. According to the phenotypic, genetic and chemotaxonomic evidence, strain MAHUQ-46T was clearly distinguishable from validly published species of genus Paenibacillus and should, therefore, be categorized as a novel species for which the name Paenibacillus roseus sp. nov. is proposed. The type strain is MAHUQ-46T (= KACC 21242T = CGMCC 1.17353T).

Ginsenosides in vascular remodeling: Cellular and molecular mechanisms of their therapeutic action.

Evidence is mounting that abnormal vascular remodeling (VR) is a vital pathological event that precedes many cardiovascular diseases (CVD). This provides us with a new research perspective that VR can be a pivotal target for CVD treatment and prevention. However, the current drugs for treating CVD do not fundamentally reverse VR and repair vascular function. The reason may be that a complicated regulatory network is formed between the various signaling pathways involved in VR. Recently, ginsenoside, the main active substance of ginseng, has become increasingly the focus of many researchers for its multiple targets, multiple pathways, and few side effects. Several data have revealed that ginsenosides can improve VR caused by vasodilation dysfunction, abnormal vascular structure and blood pressure. This review is intended to discuss the therapeutic effects and mechanisms of ginsenosides in some diseases involved in VR. Besides, we herein also give a new and contradictory insight into intracellular and molecular signaling of ginsenosides in all kinds of vascular cells. Most importantly, we also discuss the feasibility of ginsenosides Rb1/Rg1/Rg3 in drug development by combining the pharmacodynamics and pharmacokinetics of ginsenosides, and provide a pharmacological basis for the development of ginsenosides in clinical applications.

Biotransformation of ginsenoside Rc to Rd by endophytic bacterium Bacillus sp. G9y isolated from Panax quinquefolius.

To isolate endophytic bacterium with the ability to specifically convert ginsenoside Rc from Panax quinquefolius. An endophytic bacterium G9y was isolated from Panax quinquefolius and indentified as Bacillus sp. based on 16s rDNA gene sequence. Ginsenoside Rc was effectively converted to Rd by G9y, which was confirmed by thin-layer chromatography and high performance liquid chromatography (HPLC) analysis. The biotransformation conditions were further optimized as follows: inoculum amount 5%, converting temperature 45 °C, medium beef extract peptone broth at pH of 7, and the time of Rc addition was 4 h after bacterium G9y growth, under which ginsenoside Rc was completely converted to Rd by bacterium G9y within 25 h after inoculation. A strain of G9y with the ability to convert ginsenoside Rc into Rd was screened from endophytic bacteria isolated from P. quinquefolius. The results provide a new microbial resource for preparing ginsenoside Rd via biotransformation, and explore a pathway for Rc utilization, which has great potential application value.

Preparative separation of gypenoside XVII, ginsenoside Rd2, and notoginsenosides Fe and Fd from Panax notoginseng leaves by countercurrent chromatography and orthogonality evaluation for their separation.

The minor ginsenosides with less polarity may have more potent biological activities. Four minor saponins, i.e., gypenoside XVII, ginsenoside Rd2, notoginsenoside Fe, and notoginsenoside Fd, were successfully separated from Panax notoginseng leaves (PNL) after biotransformation by one-step countercurrent chromatography using the biphasic solvent system consisting of n-butanol-ethyl acetate-water (1:4:5, v/v/v). 30 mg of the refined extract of PNL produced 1 mg of gypenoside XVII, 4 mg of notoginsenoside Fe, 2.5 mg of ginsenoside Rd2, and 8.4 mg of notoginsenoside Fd, with purity of 74.9, 95.2, 87.3, and 97.6%, respectively. Besides, orthogonality evaluation for the separation of the four saponins using countercurrent chromatography and liquid chromatography was discussed. Four minor saponins were successfully separated from each other on a preparative scale by countercurrent chromatography from PNL, which will facilitate to provide ample of these minor saponins for further pharmacological studies.

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 ß-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 Km of BsAbfA for pNP-α-Araf and ginsenoside Rc were 0.6 mM and 0.4 mM, while the Kcat/Km 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.

Chemical constituents of Panax ginseng and Panax notoginseng explain why they differ in therapeutic efficacy.

Panax ginseng (Meyer) and Panax notoginseng (Burkill), belonging to the family Araliaceae, are used worldwide as medicinal and functional herbs. Numerous publications over the past decades have revealed that both P. notoginseng and P. ginseng contain important bioactive ingredients such as ginsenosides and exert multiple pharmacological effects on nervous system and immune diseases. However, based on traditional Chinese medicine (TCM) theory, their applications clearly differ as ginseng reinforces vital energy and notoginseng promotes blood circulation. In this article, we review the similarities and differences between ginseng and notoginseng in terms of their chemical composition and pharmacological effects. Their chemical comparisons indicate that ginseng contains more polysaccharides and amino acids, while notoginseng has more saponins, volatile oil, and polyacetylenes. Regarding pharmacological effects, ginseng exhibits better protective effects on cardiovascular disease, nerve disease, cancer, and diabetes mellitus, whereas notoginseng displays a superior protective effect on cerebrovascular disease. The evidence presented in this review facilitates further research and clinical applications of these two herbs, and exploration of the relationship between the chemical components and disease efficacy may be the critical next step.

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.

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 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.

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 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.

Characterization of a novel arabinose-tolerant α-L-arabinofuranosidase with high ginsenoside Rc to ginsenoside Rd bioconversion productivity.

AIMS: (i) To investigate the enzymatic characterization of α-L-arabinofuranosidase from Thermotoga thermarum DSM5069. (ii) To evaluate the performance of its excellent properties on converting ginsenoside Rc to ginsenoside Rd. METHODS AND RESULTS: The thermostable α-L-arabinofuranosidase (Tt-Afs) gene from T. thermarum DSM5069 was cloned and overexpressed. Recombinant Tt-Afs was purified, and its molecular weight was approx. 55 kDa. Its optimal activity was at pH 5·0 and 95°C. It has high selectivity for cleaving the outer arabinofuranosyl moieties at the C-20 carbon of ginsenoside Rc and its sugar-tolerance makes Tt-Afs a promising candidate for the production of ginsenoside Rd. In a reaction at 85°C and pH 5·0, 25 g l(-1) of ginsenoside Rc was transformed into 21·8 g l(-1) of Rd within 60 min, with a corresponding molar conversion of 99·4% and a high ginsenoside Rd productivity of 21800 mg l(-1) h(-1). CONCLUSIONS: We have successfully cloned and overexpressed the novel α-l-arabinofuranosidase from T. thermarum DSM5069. The high ginsenoside Rd productivity and detailed characterization of recombinant Tt-Afs was provided. SIGNIFICANCE AND IMPACT OF THE STUDY: The result shows a high productivity on the bioconversion from high concentration ginsenoside Rc to ginsenoside Rd, which also give rise to a potential commercial enzyme application.

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.