Effects of mRg2, a mixture of ginsenosides containing 60% Rg2, on the ultraviolet B-induced DNA repair synthesis and apoptosis in NIH3T3 cells

Ginsenoside Rg2 protects cardiomyocytes against trastuzumab-induced toxicity by inducing autophagy

Trastuzumab (TZM) significantly improves the outcomes of patients with breast cancer; however, it is associated with severe cardiotoxicity. Ginsenoside Rg2 was reported to exert protective effects against myocardial injury and apoptosis in human cardiomyocytes (HCMs). However, whether ginsenoside Rg2 protects HCMs against TZM-induced toxicity remains unclear. The present study investigated the proliferation of HCMs using a Cell Counting Kit-8 assay and Ki67 immunofluorescence staining. Apoptotic cells were detected by Annexin V/propidium iodide staining and flow cytometry. Furthermore, monodansylcadaverine staining was performed to detect cell autophagy. In addition, western blotting was used to detect the expression levels of phosphorylated (p)-Akt, p-mTOR, beclin 1, microtubule associated protein 1 light chain 3α (LC3) and autophagy protein 5 (ATG5) in HCMs. Pretreatment with ginsenoside Rg2 significantly protected HCMs against TZM-induced cytotoxicity by inhibiting apoptosis. Furthermore, pretreatment with ginsenoside Rg2 induced autophagy in HCMs by upregulating the expression levels of p-Akt, p-mTOR, beclin 1, LC3 and ATG5. The results obtained in the present study suggested that ginsenoside Rg2 could protect HCMs against TZM-induced cardiotoxicity by activating autophagy. Therefore, ginsenoside Rg2 may serve as a potential therapeutic agent to prevent TZM-related cardiotoxicity in patients with breast cancer.

Genome-Protecting Compounds as Potential Geroprotectors

Throughout life, organisms are exposed to various exogenous and endogenous factors that cause DNA damages and somatic mutations provoking genomic instability. At a young age, compensatory mechanisms of genome protection are activated to prevent phenotypic and functional changes. However, the increasing stress and age-related deterioration in the functioning of these mechanisms result in damage accumulation, overcoming the functional threshold. This leads to aging and the development of age-related diseases. There are several ways to counteract these changes: 1) prevention of DNA damage through stimulation of antioxidant and detoxification systems, as well as transition metal chelation; 2) regulation of DNA methylation, chromatin structure, non-coding RNA activity and prevention of nuclear architecture alterations; 3) improving DNA damage response and repair; 4) selective removal of damaged non-functional and senescent cells. In the article, we have reviewed data about the effects of various trace elements, vitamins, polyphenols, terpenes, and other phytochemicals, as well as a number of synthetic pharmacological substances in these ways. Most of the compounds demonstrate the geroprotective potential and increase the lifespan in model organisms. However, their genome-protecting effects are non-selective and often are conditioned by hormesis. Consequently, the development of selective drugs targeting genome protection is an advanced direction.

Upregulation of autophagy by Ginsenoside Rg2 in MCF-7 cells

Autophagy is a major intracellular degradation process that plays an important role in cell survival, stress responses, nutrient sensing and development. Our previous studies have shown that Rg2, a triterpenoid saponin contained in ginseng, protects cells against UVB-induced genotoxicity by increasing DNA repair, in possible association with modulation of protein levels involved in p53 pathway. In this study, we determined an upregulation of autophagy by Rg2. Rg2 treatment for 24 h in MCF-7, a breast cancer cell, did not show cytotoxicity up to 200 μM. Rg2 also upregulated the level of p-p53, p-AMPK, p-ACC, Atg-7 and LC3-II and decreased the level of p62 in concentration-dependent manners. We also determined the level of p53, AMPK, p62, Atg-7 and LC3 after UVB exposure and subsequent incubation in growth medium for 24 h. UVB increased the level of p-p53, p-AMPK, p-ACC and decreased the levels of p62, Atg-7 and LC3-II. Interestingly, Rg2 treatment for 24 h after UVB exposure increased the levels of p-p53, p-AMPK, p-ACC, Atg-7 and LC3-II and decreased the level of cyclobutane pyrimidine dimer, a UVB-induced DNA damage in concentration-dependent manners. All these results suggest that Rg2 increased autophagy and decreased UVB-induced DNA damage, in possible association with the modulation of protein levels in p53- and autophagic pathways.

Protective effects of ginsenoside Rg2 and astaxanthin mixture against UVB-induced DNA damage

Ultraviolet B (UVB) radiation induces skin damage, skin matrix degradation, and wrinkle formation through photochemical reaction and oxidative stress. Therefore, protecting the skin from UVB can prevent skin aging. In this study, we investigated the effects of a mixture (RA) of Rg2, a ginsenoside, and astaxanthin, an antioxidant, on the responses of HaCaT cells exposed to UVB (700 J/m²). The cells were incubated for 24 h after UVB exposure and cell viability was determined by MTT assay. UVB decreased cell viability by 60% compared to that of untreated control cells, whereas RA increased cell viability in a concentration-dependent manner, and this increase was significantly higher than that in the single treatment groups. Further, UVB increased the levels of DNA lesions such as cyclobutane pyrimidine dimer (CPD) and 8-hydroxyguanine (8-OHdG). Conversely, RA decreased both CPD and 8-OHdG levels in a concentration-dependent manner. UVB exposure also increased phosphorylation of ataxia-telangiectasia mutated (ATM) protein kinase and p53 and subsequently increased the levels of GADD45α, p21, and matrix metalloproteinases (MMPs)-3, -9, and -13. Additionally, UVB exposure decreased the level of COL1A1. However, RA treatment decreased the levels of p-ATM, p-p53, GADD45α, p21, MMP-3, -9, and -13 and increased the level of COL1A1 in a concentration-dependent manner. These results suggest that RA reduces UVB-induced cytotoxicity and genotoxicity through up-regulation of DNA repair via the combined effects of Rg2 and astaxanthin.

Identification and characterization of a ginsenoside-transforming β-glucosidase from Pseudonocardia sp. Gsoil 1536 and its application for enhanced production of minor ginsenoside Rg2(S)

The ginsenoside Rg₂(S), which is one of the pharmaceutical components of ginseng, is known to have neuroprotective, anti-inflammation, and anti-diabetic effects. However, the usage of ginsenoside Rg₂(S) is restricted owing to the small amounts found in white and red ginseng. To enhance the production of ginsenoside Rg₂(S) as a 100 gram unit with high specificity, yield, and purity, an enzymatic bioconversion method was developed to adopt the recombinant glycoside hydrolase (BglPC28), which is a ginsenoside-transforming recombinant β-glucosidase from Pseudonocardia sp. strain Gsoil 1536. The gene, termed bglPC28, encoding β-glucosidase (BglPC28) belonging to the glycoside hydrolase family 3 was cloned. bglPC28 consists of 2,232 bp (743 amino acid residues) with a predicted molecular mass of 78,975 Da. This enzyme was overexpressed in Escherichia coli BL21(DE3) using a GST-fused pGEX 4T-1 vector system. The optimum conditions of the recombinant BglPC28 were pH 7.0 and 37°C. BglPC28 can effectively transform the ginsenoside Re to Rg₂(S); the K_m values of PNPG and Re were 6.36±1.10 and 1.42±0.13 mM, respectively, and the V_max values were 40.0±2.55 and 5.62±0.21 µmol min⁻¹ mg⁻¹ of protein, respectively. A scaled-up biotransformation reaction was performed in a 10 L jar fermenter at pH 7.0 and 30°C for 12 hours with a concentration of 20 mg/ml of ginsenoside Re from American ginseng roots. Finally, 113 g of Rg₂(S) was produced from 150 g of Re with 84.0±1.1% chromatographic purity. These results suggest that this enzymatic method could be usefully exploited in the preparation of ginsenoside Rg₂(S) in the cosmetics, functional food, and pharmaceutical industries.

Changes in ginsenoside composition of ginseng berry extracts after a microwave and vinegar process

MGB-20 findings show that the ginseng berry extracts that had been processed with microwave and vinegar for 20 min peaked in the level of ginsenoside Rg2 (2.28%) and Rh1 (1.28%). MGB-1 peaked in the level of ginsenoside Rg3 (1.13%) in the ginseng berry extract processed with microwave and vinegar for 1 min.

Protective Effect of Processed Panax ginseng, Sun Ginseng on UVB-irradiated Human Skin Keratinocyte and Human Dermal Fibroblast

In this study, we investigated the protective effects of processed Panax ginseng, sun ginseng (SG) against the UVB-irradiation on epidermal keratinocytes and dermal fibroblasts. Pretreatment of SG in HaCaT keratinocytes and human dermal fibroblasts reduced UVB-induced cell damage as seen by reduced lactate dehydrogenase release. We also found that SG restored the UVB-induced decrease in anti-apoptotic gene expression (bcl-2 and bcl-xL) in these cells, indicating that SG has an anti-apoptotic effect and thus can protect cells from cell death caused by strong UVB radiation. In addition, SG inhibited the excessive expression of c-jun and c-fos gene by the UVB in HeCaT cells and human dermal fibroblasts. We also demonstrated that SG may exert an anti-inflammatory activity by reducing the nitric oxide production and inducible nitric oxide synthase mRNA synthesis in HaCaT keratinocytes and human dermal fibroblasts. This was further supported by its inhibitory effects on the elevated cyclooxygenase-2 and tumor necrosis factor-α transcription which was induced by UVB-irradiation in HaCaT cells. In addition, SG may have anti-aging property in terms of induction of procollagen gene expression and inhibition of the matrix metalloprotease-1 gene expression caused by UVBexposure. These findings suggest that SG can be a potential agent that may protect against the dermal cell damage caused by UVB.

Ginsenoside Rb1, Rg1 and three extracts of traditional Chinese medicine attenuate ultraviolet B-induced G1 growth arrest in HaCaT cells and dermal fibroblasts involve down-regulating the expression of p16, p21 and p53

OBJECTIVE

The aims of this study were to confirm whether traditional Chinese medicine ginsenoside Rb1 (Rb1), ginsenoside Rg1 (Rg1), polygonum multiflorum (PM), ginkgo extract (GE) and lycium barbarum polysaccharide (LBP) can attenuate G1 growth arrest of HaCaT cells and dermal fibroblasts induced by 10 subcytotoxic ultraviolet B (UVB) exposures, and to explore the possible mechanism in terms of the expression of cell-cycle regulatory proteins p16, p21 and p53.

METHODS

Ten subcytotoxic exposures to UVB induced G1 growth arrest of HaCaT cells and dermal fibroblasts. Cell-cycle analysis was performed using flow cytometry, and mRNA levels of p16, p21 and p53 were detected by a reverse transcription-polymerase chain reaction (RT-PCR), and protein levels were detected using Western blot analysis.

RESULTS

Five types of traditional Chinese medicine attenuated UVB-induced G1 growth arrest. The mRNA and protein levels of p16, p21 and p53 in HaCaT cells and dermal fibroblasts increased after UVB irradiation, but pretreatment with five types of traditional Chinese medicine decreased the expression of p16, p21 and p53.

CONCLUSIONS

These results indicated that five types of traditional Chinese medicine can attenuate G1 growth arrest of HaCaT cells and dermal fibroblasts induced by UVB exposures, which was caused by down-regulating the expression of cell-cycle regulatory proteins p16, p21 and p53.

Effects of ginsenoside Rg2 on the ultraviolet B-induced DNA damage responses in HaCaT cells

Our previous study demonstrated the increase in the repair of UVB damage by mRg2, a mixture of ginsenosides containing 60% Rg2 in NIH3T3 cells. In the present study, the effects of purified Rg2 on the repair and apoptosis in ultraviolet B (UVB)-exposed HaCaT cells were investigated on gene expression levels. When cells were exposed to UVB and post-incubated in normal medium for 24 h, the cell viability decreased to about 50% of that in nontreated control. When Rg2 was post-incubated, however, the UVB-induced cytotoxicity was significantly prevented in an Rg2 concentration- and time-dependent manner. The apoptotic nuclear fragmentation resulting from UVB exposure was also significantly protected by the Rg2 post-incubation. Microarray analysis showed that the genes stimulated by the Rg2-alone treatment include those involved in p53 signaling pathway such as GADD45alpha, GADD45beta, and cell communication genes. RT-PCR analysis showed that the Rg2-alone treatment slightly upregulated the p53 and GADD45 transcript and protein levels by about 1.5-fold as compared with the nontreated control. The mRNA levels of p53 and GADD45 in cells exposed to UVB and post-incubated with Rg2 for 24 h decreased in an Rg2 concentration-dependent manner as compared with that post-incubated in normal medium. However, the mRNA level of the UVB-exposed cells post-incubated with 5 microM retinol was essentially the same as that post-incubated in normal medium. Time course experiment showed that the mRNA levels of p53 and GADD45 in UVB-exposed cells were upregulated by post-incubation with 50 microM Rg2 until 6 and 9 h, respectively, and then gradually decreased until 24 h. By Western blot analysis, it was also revealed that the Rg2 post-incubation decreases the expression of p53, phospho-p53, GADD45, and ATM in UVB-exposed cells. Time course analysis also indicated that these decreased expressions were due to the earlier upregulation of p53 and GADD45 proteins. When UVB-exposed cells were post-incubated with Rg2 for 24 h after UVB exposure, the level of remaining cyclobutane pyrimidine dimers decreased in both Rg2 concentration- and time-dependent manner. All these results suggest that Rg2 protects cells against UVB-induced genotoxicity by increasing DNA repair, in possible association with modulation of protein levels involved in p53 signaling pathway.

American ginseng suppresses colitis through p53-mediated apoptosis of inflammatory cells

Ulcerative colitis is a dynamic, chronic inflammatory condition associated with an increased colon cancer risk. Inflammatory cell apoptosis is a key mechanism regulating ulcerative colitis. American ginseng (AG) is a putative antioxidant that can suppress hyperactive immune cells. We have recently shown that AG can prevent and treat mouse colitis. Because p53 levels are elevated in inflammatory cells in both mouse and human colitis, we tested the hypothesis that AG protects from colitis by driving inflammatory cell apoptosis through a p53 mechanism. We used isogenic p53(+/+) and p53(-/-) inflammatory cell lines as well as primary CD4(+)/CD25(-) effector T cells from p53(+/+) and p53(-/-) mice to show that AG drives apoptosis in a p53-dependent manner. Moreover, we used a dextran sulfate sodium (DSS) model of colitis in C57BL/6 p53(+/+) and p53(-/-) mice to test whether the protective effect of AG against colitis is p53 dependent. Data indicate that AG induces apoptosis in p53(+/+) but not in isogenic p53(-/-) cells in vitro. In vivo, C57BL/6 p53(+/+) mice are responsive to the protective effects of AG against DSS-induced colitis, whereas AG fails to protect from colitis in p53(-/-) mice. Furthermore, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling of inflammatory cells within the colonic mesenteric lymph nodes is elevated in p53(+/+) mice consuming DSS + AG but not in p53(-/-) mice consuming DSS + AG. Results are consistent with our in vitro data and with the hypothesis that AG drives inflammatory cell apoptosis in vivo, providing a mechanism by which AG protects from colitis in this DSS mouse model.

Panax ginseng ginsenoside-Rg2 protects memory impairment via anti-apoptosis in a rat model with vascular dementia

ETHNOPHARMACOLOGICAL RELEVANCE

Ginsenosides, the major active ingredients of Panax ginseng, produce a variety of pharmacological or physiological responses with effects on the central and peripheral nervous systems.

AIM OF THE STUDY

In this report, we investigated the effects of ginsenoside Rg2 on cerebral ischemia-reperfusion induced impairment of neurological responses, memory and caudate-putamen neuronal apoptosis in a vascular dementia (VD) rat model.

MATERIALS AND METHODS

Neurological evaluation was performed 24h after reperfusion and Y-maze memory performance was assessed at 48 h after reperfusion. Immunocytochemical techniques were employed to check the protein expression of BCL-2, BAX, heat shock protein 70 and P53, which are related with cell apoptosis.

RESULTS

Neurological responses and memory ability of the ginsenoside Rg2 or nimodipine groups improved significantly compared with the VD group. The expression of BCL-2 and HSP70 were decreased, while BAX and P53 were increased in the VD model. The expression of BCL-2 and HSP70 proteins were increased, while BAX and P53 decreased after ginsenoside Rg2 (2.5, 5 and 10mg/kg) and nimodipine (50 microg/kg) treatment compared with the VD group. The study suggests that ginsenoside Rg2 improved neurological performance and memory ability of VD rats through mechanisms related to anti-apoptosis.

CONCLUSIONS

The capacity for ginsenoside Rg2 to modulate the expression of apoptotic related proteins suggests that ginsenoside Rg2 may represent a potential treatment strategy for vascular dementia or other ischemic insults.