Ginsenoside Rg5

Int Immunopharmacol. 2012 Jan;12(1):110-6.

Ginsenoside Rg5 ameliorates lung inflammation in mice by inhibiting the binding of LPS to toll-like receptor-4 on macrophages.[Pubmed: 22107725]

Heating and steaming processes have been applied to various natural medicines for either enhancing or altering their pharmacological activities, and the chemical compositions of the active components. While ginsenoside Rb1, which is the major constituent of raw ginseng, has been studied extensively for its anti-inflammatory effect, the biological activity of Ginsenoside Rg5, a major constituent of steamed ginseng, remains to be explored.
METHODS AND RESULTS:
Here, we isolated Rg5 and examined anti-inflammatory effect in lipopolysaccharide (LPS)-stimulated macrophages and on LPS-induced lung inflammation. Rg5 inhibited the expression of proinflammatory cytokines, IL-1β and TNF-α, as well as inflammatory enzymes, COX-2 and iNOS in LPS-stimulated alveolar macrophages. Rg5 also reduced LPS-induced phosphorylation of IL-1 receptor-associated kinases (IRAK)-1 and IKK-β, as well as the degradation of IRAK-1 and IRAK-4. Rg5 inhibited the phosphorylation of NF-κB as well as the translocation of p65 into the nucleus. When macrophages were treated with Alexa Fluor 594-conjugated LPS in the presence of Rg5, the fluorescence intensity of LPS observed outside the cell membrane was lower than that in LPS-stimulated alveolar macrophages alone. Rg5, inhibited the levels of protein and neutrophils in bronchoalveolar lavage fluid of LPS-stimulated mice, as well as pro-inflammatory cytokines, TNF-α and IL-1β. Rg5 also inhibited iNOS and COX expressions, and NF-κB activation in LPS-stimulated lung inflammation of mice. The inhibitory effect of Rg5 (10 mg/kg) was comparable to that of dexamethasone (5 mg/kg).
CONCLUSIONS:
Based on these findings, Rg5 can ameliorate lung inflammation possibly by inhibiting the binding of LPS to toll-like receptor (TLR)-4 on macrophages.

J Biol Chem . 2015 Jan 2;290(1):467-77.

Specific activation of insulin-like growth factor-1 receptor by ginsenoside Rg5 promotes angiogenesis and vasorelaxation[Pubmed: 25391655]

Abstract Ginsenoside Rg5 is a compound newly synthesized during the steaming process of ginseng; however, its biological activity has not been elucidated with regard to endothelial function. We found that Rg5 stimulated in vitro angiogenesis of human endothelial cells, consistent with increased neovascularization and blood perfusion in a mouse hind limb ischemia model. Rg5 also evoked vasorelaxation in aortic rings isolated from wild type and high cholesterol-fed ApoE(-/-) mice but not from endothelial nitric-oxide synthase (eNOS) knock-out mice. Angiogenic activity of Rg5 was highly associated with a specific increase in insulin-like growth factor-1 receptor (IGF-1R) phosphorylation and subsequent activation of multiple angiogenic signals, including ERK, FAK, Akt/eNOS/NO, and Gi-mediated phospholipase C/Ca(2+)/eNOS dimerization pathways. The vasodilative activity of Rg5 was mediated by the eNOS/NO/cGMP axis. IGF-1R knockdown suppressed Rg5-induced angiogenesis and vasorelaxation by inhibiting key angiogenic signaling and NO/cGMP pathways. In silico docking analysis showed that Rg5 bound with high affinity to IGF-1R at the same binding site of IGF. Rg5 blocked binding of IGF-1 to its receptor with an IC50 of ～90 nmol/liter. However, Rg5 did not induce vascular inflammation and permeability. These data suggest that Rg5 plays a novel role as an IGF-1R agonist, promoting therapeutic angiogenesis and improving hypertension without adverse effects in the vasculature. Keywords: Angiogenesis; Endothelial Cell; Insulin-like Growth Factor (IGF); Insulin-like Growth Factor-1 Receptor; Nitric Oxide; Vascular Biology; Vascular Function.

J Ginseng Res . 2015 Apr;39(2):125-34.

Anti-breast cancer activity of Fine Black ginseng (Panax ginseng Meyer) and ginsenoside Rg5[Pubmed: 26045685]

Abstract Background: Black ginseng (Ginseng Radix nigra, BG) refers to the ginseng steamed for nine times and fine roots (hairy roots) of that is called fine black ginseng (FBG). It is known that the content of saponin of FBG is higher than that of BG. Therefore, in this study, we examined antitumor effects against MCF-7 breast cancer cells to target the FBG extract and its main component, Ginsenoside Rg5 (Rg5). Methods: Action mechanism was determined by MTT assay, cell cycle assay and western blot analysis. Results: The results from MTT assay showed that MCF-7 cell proliferation was inhibited by Rg5 treatment for 24, 48 and 72 h in a dose-dependent manner. Rg5 at different concentrations (0, 25, 50 and 100 μM), induced cell cycle arrest in G0/G1 phase through regulation of cell cycle-related proteins in MCF-7 cells. As shown in the results from western blot analysis, Rg5 increased expression of p53, p21(WAF1/CIP1) and p15(INK4B) and decreased expression of Cyclin D1, Cyclin E2 and CDK4. Expression of apoptosis-related proteins including Bax, PARP and Cytochrome c was also regulated by Rg5. These results indicate that Rg5 stimulated cell apoptosis and cell cycle arrest at G0/G1 phase via regulation of cell cycle-associated proteins in MCF-7 cells. Conclusion: Rg5 promotes breast cancer cell apoptosis in a multi-path manner with higher potency compared to 20(S)-ginsenoside Rg3 (Rg3) in MCF-7 (HER2-/ER+) and MDA-MB-453 (HER2+/ER-) human breast cancer cell lines, and this suggests that Rg5 might be an effective natural new material in improving breast cancer. Keywords: Fine Black ginseng (Panax ginseng Meyer); anticancer; breast cancer; cell cycle arrest; Ginsenoside Rg5.

Int Immunopharmacol. 2014 Apr;19(2):317-26.

Ginsenoside Rg5 improves cognitive dysfunction and beta-amyloid deposition in STZ-induced memory impaired rats via attenuating neuroinflammatory responses.[Pubmed: 24503167]

Neuroinflammatory responses play a crucial role in the pathogenesis of Alzheimer's disease (AD). Ginsenoside Rg5 (Rg5), an abundant natural compound in Panax ginseng, has been found to be beneficial in treating AD.
METHODS AND RESULTS:
In the present study, we demonstrated that Ginsenoside Rg5 improved cognitive dysfunction and attenuated neuroinflammatory responses in streptozotocin (STZ)-induced memory impaired rats. Cognitive deficits were ameliorated with Ginsenoside Rg5 (5, 10 and 20mg/kg) treatment in a dose-dependent manner together with decreased levels of inflammatory cytokines TNF-α and IL-1β (P<0.05) in brains of STZ rats. Acetylcholinesterase (AChE) activity was also significantly reduced by Ginsenoside Rg5 whereas choline acetyltransferase (ChAT) activity was remarkably increased in the cortex and hippocampus of STZ-induced AD rats (P<0.05). Western blot analysis also demonstrated that Ginsenoside Rg5 increased remarkably BDNF and IGF-1 expressions whereas decreased significantly Aβ deposits (P<0.05). Furthermore, it was observed that the expressions of COX-2 and iNOS were significantly up-regulated in STZ-induced AD rats and down-regulated strongly (P<0.05) by Ginsenoside Rg5 compared with control rats. These data demonstrated that STZ-induced learning and memory impairments in rats could be improved by Ginsenoside Rg5, which was associated with attenuating neuroinflammatory responses.
CONCLUSIONS:
Our findings suggested that Ginsenoside Rg5 could be a beneficial agent for the treatment of AD.

J Biol Chem. 2015 Jan 2;290(1):467-77.

Specific activation of insulin-like growth factor-1 receptor by ginsenoside Rg5 promotes angiogenesis and vasorelaxation.[Pubmed: 25391655 ]

Ginsenoside Rg5 is a compound newly synthesized during the steaming process of ginseng; however, its biological activity has not been elucidated with regard to endothelial function.
METHODS AND RESULTS:
We found that Rg5 stimulated in vitro angiogenesis of human endothelial cells, consistent with increased neovascularization and blood perfusion in a mouse hind limb ischemia model. Rg5 also evoked vasorelaxation in aortic rings isolated from wild type and high cholesterol-fed ApoE(-/-) mice but not from endothelial nitric-oxide synthase (eNOS) knock-out mice. Angiogenic activity of Rg5 was highly associated with a specific increase in insulin-like growth factor-1 receptor (IGF-1R) phosphorylation and subsequent activation of multiple angiogenic signals, including ERK, FAK, Akt/eNOS/NO, and Gi-mediated phospholipase C/Ca(2+)/eNOS dimerization pathways. The vasodilative activity of Rg5 was mediated by the eNOS/NO/cGMP axis. IGF-1R knockdown suppressed Rg5-induced angiogenesis and vasorelaxation by inhibiting key angiogenic signaling and NO/cGMP pathways. In silico docking analysis showed that Rg5 bound with high affinity to IGF-1R at the same binding site of IGF. Rg5 blocked binding of IGF-1 to its receptor with an IC50 of ∼90 nmol/liter. However, Rg5 did not induce vascular inflammation and permeability.
CONCLUSIONS:
These data suggest that Rg5 plays a novel role as an IGF-1R agonist, promoting therapeutic angiogenesis and improving hypertension without adverse effects in the vasculature.

Int J Mol Sci. 2013 May 8;14(5):9820-33.

Anti-Inflammatory Effect of Ginsenoside Rg5 in Lipopolysaccharide-Stimulated BV2 Microglial Cells.[Pubmed: 23698769]

Microglia are resident immune cells in the central nervous system. They play a role in normal brain development and neuronal recovery. However, overactivation of microglia causes neuronal death, which is associated with neurodegenerative diseases, such as Parkinson's disease and Alzheimer's disease. Therefore, controlling microglial activation has been suggested as an important target for treatment of neurodegenerative diseases.
METHODS AND RESULTS:
In the present study, we investigated the anti-inflammatory effect of Ginsenoside Rg5 in lipopolysaccharide (LPS)-stimulated BV2 microglial cells and rat primary microglia. The data showed that Rg5 suppressed LPS-induced nitric oxide (NO) production and proinflammatory TNF-α secretion. In addition, Rg5 inhibited the mRNA expressions of iNOS, TNF-α, IL-1b, COX-2 and MMP-9 induced by LPS. Further mechanistic studies revealed that Rg5 inhibited the phophorylations of PI3K/Akt and MAPKs and the DNA binding activities of NF-kB and AP-1, which are upstream molecules controlling inflammatory reactions. Moreover, Rg5 suppressed ROS production with upregulation of hemeoxygenase-1 (HO-1) expression in LPS-stimulated BV2 cells.
CONCLUSIONS:
Overall, microglial inactivation by Ginsenoside Rg5 may provide a therapeutic potential for various neuroinflammatory disorders.

Anticancer Res. 1997 Mar-Apr;17(2A):1067-72.

Ginsenoside-Rg5 suppresses cyclin E-dependent protein kinase activity via up-regulating p21Cip/WAF1 and down-regulating cyclin E in SK-HEP-1 cells.[Pubmed: 9137450]

In the present study, we report that Ginsenoside Rg5 (G-Rg5), a newly discovered diol-containing ginsenoside, blocks the cell cycle of human hepatoma SK-HEP-1 cells via the down-regulation of cyclin E-dependent kinase activity.
METHODS AND RESULTS:
The results from flow cytometric analyses show that Ginsenoside Rg5 arrests the cell cycle of SK-HEP-1 cells at the Gl/S transition phase. The cyclin E-dependent kinase activity that has been immunoprecipitated with cyclin E-specific antibody is down-regulated in response to Ginsenoside Rg5. The results from immunoblottings show that the down-regulation of cyclin E-dependent kinase activity is related to increased protein levels of p21Cip/WAF1 and to decreased protein levels of cyclin E, CDK2, and CDC25A.
CONCLUSIONS:
Collectively, these data suggest that Ginsenoside Rg5 blocks cell cycle of SK-HEP-1 cells at the Gl/S transition phase by down-regulating cyclin E-dependent kinase activity and that the down-regulation of cyclin E-dependent kinase activity is caused mainly by induced CDK2 inhibitor, p21Cip/WAF1 and decreased levels of cyclin E.