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

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.

The activation of PPARγ by 2,4,6-Octatrienoic acid protects human keratinocytes from UVR-induced damages

Increasing attention is addressed to identify products able to enhance skin photoprotection and to prevent skin carcinogenesis. Several studies have demonstrated that the α-melanocyte stimulating hormone (αMSH), acting on a functional MC1R, provides a photoprotective effect by inducing pigmentation, antioxidants and DNA repair. We discovered a link between αMSH and the nuclear receptor Peroxisome Proliferator-Activated Receptor-γ (PPARγ), suggesting that some of the αMSH protective effects may be dependent on PPARγ transcriptional activity. Moreover, we demonstrated that the activation of PPARγ by the parrodiene 2,4,6-octatrienoic acid (Octa) induces melanogenesis and antioxidant defence in human melanocytes and counteracts senescence-like phenotype in human fibroblasts. In this study, we demonstrate that the activation of PPARγ by Octa exerts a protective effect against UVA- and UVB-induced damage on normal human keratinocytes (NHKs), the major target cells of UV radiation. Octa promotes the antioxidant defence, augments DNA repair and reduces the induction of proteins involved in UV-induced DNA damage response. Our results contribute to deepen the analysis of the αMSH/PPARγ connection and suggest perspectives for the development of new molecules and formulations able to prevent cutaneous UV damage by acting on the different skin cell populations through PPARγ activation.

Effect of Korean Red Ginseng in chronic liver disease

Chronic liver disease, one of the most common diseases, typically arises from nonalcoholic fatty liver disease, alcoholic liver disease, chronic viral hepatitis, or hepatocellular carcinoma. Therefore, there is a pressing need for improved treatment strategies. Korean Red Ginseng has been known to have positive effects on liver disease and liver function. In this paper, we summarize the current knowledge on the beneficial effects of Korean Red Ginseng on chronic liver disease, a condition encompassing nonalcoholic fatty liver disease, alcoholic liver disease, chronic viral hepatitis, and hepatocellular carcinoma, as supported by experimental evaluation and clinical investigation.

Saponins from Chinese Medicines as Anticancer Agents

Saponins are glycosides with triterpenoid or spirostane aglycones that demonstrate various pharmacological effects against mammalian diseases. To promote the research and development of anticancer agents from saponins, this review focuses on the anticancer properties of several typical naturally derived triterpenoid saponins (ginsenosides and saikosaponins) and steroid saponins (dioscin, polyphyllin, and timosaponin) isolated from Chinese medicines. These saponins exhibit in vitro and in vivo anticancer effects, such as anti-proliferation, anti-metastasis, anti-angiogenesis, anti-multidrug resistance, and autophagy regulation actions. In addition, related signaling pathways and target proteins involved in the anticancer effects of saponins are also summarized in this work.

Cytotoxicity and gene expression in sarcoma 180 cells in response to spiky magnetoplasmonic supraparticles

Multifunctional nanoparticles (NPs) have been designed for a variety of cell imaging and therapeutic applications, and the study of their cellular interactions is crucial to the development of more efficient biomedical applications. Among current nanomaterials, concave core-shell NPs with complex angled geometries are attractive owing to their unique shape-dependent optical and physical properties as well as different tendency for cell interaction. In this study, we investigated the morphology effect of spiky gold-coated iron oxide supraparticles (Fe3O4@Au SPs) on cytotoxicity and global gene expression in sarcoma 180 cells. Cells treated for 7 days with spiky supraparticles (SPs) at concentrations up to 50 μg/mL showed >90% viability, indicating that these NPs were nontoxic. To shed light on the differences in cytotoxicity, we monitored the expression of 33,315 genes using microarray analysis of SP-treated cells. The 171 up-regulated genes and 181 down-regulated genes in spiky SP-treated cells included Il1b, Spp1, Il18, Rbp4, and Il11ra1, where these genes are mainly involved in cell proliferation, differentiation, and apoptosis. These results suggested that the spiky Fe3O4@Au SPs can induce noncytotoxicity and gene expression in tumor cells, which may be a promising cornerstone on which to base related research such as cyto-/genotoxicology of nanomaterials or the design of nanoscale drug carriers.

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.

Trends in ginseng research in 2010

A total of 470 papers directly related to research on the Panax species were retrieved by performing internet searches with the keywords Panax and ginseng as the search terms. The publications were categorized as follows: 399 research articles, 30 reviews, 30 meeting abstracts, 7 proceedings, and 4 letters. The majority of these publications were published by scientists from Korea (35.7%), China (32.3%), and the USA (11.3%). Scientists from a total of 29 nations were actively involved in conducting ginseng research. A total of 43.6% of the publications were categorized as pharmacodynamic studies. The effects of ginseng on cerebrovascular function and cancer were the two most common topics considered in the pharmacodynamic studies. More than half of the ginseng studies assessed the use of P. ginseng. A total of 23 countries participated in studies specifically related to P. ginseng, and more than 80% of these studies originated from Korea and China. A total of 50 topics within the pharmacodynamics category were examined in association with the use of P. ginseng.

Comparative studies of saponins in 1-3-year-old main roots, fibrous roots, and rhizomes of Panax notoginseng, and identification of different parts and growth-year samples

Notoginsenosides R1, R4, Fa, and K (N-R1, N-R4, N-Fa, and N-K), as well as ginsenosides Rg1, Rb1, Rd, Re, Rf, Rg2 and Rh1 (G-Rg1, G-Rb1, G-Rd, G-Re, G-Rf, G-Rg2 and G-Rh1) in 47 Notoginseng samples including 1-, 2- and 3-year-old main roots, rhizomes and fibrous roots of Panax notoginseng were determined by high-performance liquid chromatography-diode array detection method. Total contents (%) of the 11 saponins were 9.82-14.57 for 2-year old and 14.20-16.00 for 3-year-old rhizomes; 2.72-4.50 for 2-year-old and 1.98-4.92 for 3-year-old fibrous roots; 1.75-3.05 for 1-year-old whole roots; and 3.71-8.98 for 2-year-old and 7.03-11.23 for 3-year-old main roots. Contents of most saponins and total content of 11 saponins were in the order 3- >2- >1-year-old main root samples. G-Rf content, sum of G-Rf and G-Rh1 were, respectively, 0.08-0.18 and 0.14-0.32 for 2- or 3-year-old rhizomes, and 0.01-0.07 and 0.03-0.10 for 2- or 3-year-old main roots. Combined contents of N-R1, G-Rg1 and G-Rb1 were 5.78-9.37 in 3-year-old main roots, and 2.99-7.13 in 2-year-old main roots, of which nearly one-third of samples were lower than the limit (5 %) in the Chinese Pharmacopoeia. Those of 2- or 3-year-old fibrous roots (1.47-3.83) and 1-year-old whole roots (1.41-2.44) were much lower than the limit, and were considered not suitable for use as Notoginseng. Two-year-old main roots are not appropriate for collection as Notoginseng. Different parts and growth years of P. notoginseng can be identified from each another according to differences in saponin content.

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.

Ginsenoside Rg2 induces orphan nuclear receptor SHP gene expression and inactivates GSK3β via AMP-activated protein kinase to inhibit hepatic glucose production in HepG2 cells

Panax ginseng is known to have anti-diabetic activity, but the active ingredients have not been fully explored yet. Here, we test whether ginsenoside Rg2 has an inhibitory effect on hepatic glucose production and determine its mechanism of action. Rg2 significantly inhibits hepatic glucose production and induces phosphorylations of liver kinase B1 (LKB1), AMP-activated protein kinase (AMPK) and glycogen synthase kinase 3β (GSK3β) in time- and concentration-dependent manners in human HepG2 hepatoma cells, and these effects were abolished in the presence of compound C, a selective AMPK inhibitor. In addition, phosphorylated form of cAMP-response element-binding protein (CREB), a key transcription factor for hepatic gluconeogenesis, was decreased in time- and concentration-dependent manners. Next, gene expression of orphan nuclear receptor small heterodimer partner (SHP) was also examined. Rg2 markedly enhanced the gene expression of SHP and its direct interaction with CREB, which results in disruption of CREB·CRTC2 complex. Consequently, expressions of relevant genes such as peroxisome proliferation-activated receptor γ coactivator-1α (PGC-1α), phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) were all significantly suppressed and these effects were also reversed in the presence of compound C. In conclusion, our results propose that ginsenoside Rg2 suppresses the hepatic glucose production via AMPK-induced phosphorylation of GSK3β and induction of SHP gene expression. Further studies are warranted to elucidate a therapeutic potential of Rg2 for type 2 diabetic patients.

Protective effects of selenocystine against γ-radiation-induced genotoxicity in Swiss albino mice

Selenocystine (CysSeSeCys), a diselenide aminoacid exhibiting glutathione peroxidase-like activity and selective antitumor effects, was examined for in vivo antigenotoxic and antioxidant activity in Swiss albino mice after exposure to a sublethal dose (5 Gy) of γ-radiation. For this, CysSeSeCys was administered intraperitoneally (i.p.) to mice at a dosage of 0.5 mg/kg body weight for 5 consecutive days prior to whole-body γ-irradiation. When examined in the hepatic tissue, CysSeSeCys administration reduced the DNA damage at 30 min after radiation exposure by increasing the rate of DNA repair. Since antigenotoxic agents could alter the expression of genes involved in cell cycle arrest and DNA repair, the transcriptional changes in p53, p21 and GADD45α were monitored in the hepatic tissue by real-time PCR. The results show that CysSeSeCys alone causes moderate induction of these three genes. However, CysSeSeCys pretreatment resulted in a suppression of radiation-induced enhancement of p21 and GADD45α expression, but did not affect p53 expression. Further analysis of radiation-induced oxidative stress markers in the same tissue indicated that CysSeSeCys significantly inhibits lipid peroxidation and prevents the depletion of antioxidant enzymes and glutathione (GSH) levels. Additionally, it also prevents radiation-induced DNA damage in other radiation sensitive cellular systems like peripheral leukocytes and bone marrow, which was evident by a decrease in comet parameters and micronucleated polychromatic erythrocytes (mn-PCEs) frequency, respectively. Based on these observations, it is concluded that CysSeSeCys exhibits antigenotoxic effects, reduces radiation-induced oxidative stress, and is a promising candidate for future exploration as a radioprotector.