• Food Science and Biotechnology
• /
• v.18 no.5
• /
• pp.1204-1211
• /
• 2009

Hericium erinaceus is an edible mushroom used as a medicinal food in Asian countries. In this study, the chemopreventive effects of H. erinaceus mycelia hot water extract (HEW) were evaluated. HEW remarkably induced the luciferase activity of the antioxidant response element (ARE), located in the promoter region of phase 2 and antioxidant genes and regulated by nuclear factor E2-related factor 2 (Nrf2). The up-regulation of ARE activity by HEW corresponded with the induction of Nrf2 and the antioxidant enzyme, hemeoxygenase-1. The inhibition of cyclooxygenase-2 (COX-2) activity is a promising effective approach in cancer chemoprevention, and HEW prominently suppressed COX-2 protein expression in HepG2 cells. Furthermore, HEW showed anti-inflammatory activity by modulating inflammatory mediators such as nitric oxide (NO), inducible NO synthase, tumor necrosis factor-${\alpha}$, interleukin-$1{\beta}$, and the transcription factor, nuclear factor-${\kappa}B$, in lipopolysaccharide-stimulated RAW 264.7 cells. These results suggest that H. erinaceus possessed anti-tumor and anti-inflammatory effects via the modulation of Nrf2/ARE and inflammatory signaling pathways, and may therefore have potential use as a natural chemopreventive agent.

• The Korea Journal of Herbology
• /
• v.30 no.4
• /
• pp.57-64
• /
• 2015

Objectives : Oxidative stress is one of the most causes of hepatocyte injury. Gleditsia spina, the thorns ofGleditsia sinensisLam., has been known for its anti-cancer and anti-inflammatory effects in Korean medicine. The present study investigated hepatoprotective effect of Gleditsia spina water extract (GSE) against oxidative stress induced by arachidonic acid (AA) + iron in HepG2 cells.Methods : To investigate cytoprotective effect of GSE, cells were pretreated with GSE and then subsequently exposed to 10 μM AA for 12 h, followed by 5 μM iron. Cell viability was monitored by MTT assay, and expression of apoptosis-related proteins was examined by immunoblot analysis. To identify responsible molecular mechanisms, reactive oxygen species (ROS) production, GSH contents, and mitochondrial membrane potential were measured. In addition, effect of GSE on nuclear factor erythroid 2-related factor 2 (Nrf2) activation was determined by immunoblot and antioxidant response element (ARE)-driven reporter gene assays.Results : GSE pretreatment prevented AA + iron-mediated cytotoxicity in concentration dependent manner. In addition, ROS production, glutathione depletion, and mitochondrial impairment by AA + iron were significantly inhibited by GSE. Furthermore, GSE promoted translocation of Nrf2 to nucleus, which acts as essential transcription factor for induction of antioxidant genes. Increased nuclear Nrf2 that caused by GSE treatment promoted transcriptional activity of ARE. Finally, GSE up-regulated sestrin-2 which was widely recognized as target gene of Nrf2.Conclusions : This study demonstrates that GSE protects hepatocytes from oxidative stress via activation of Nrf2 signaling pathway.

• Journal of Ginseng Research
• /
• v.40 no.4
• /
• pp.423-430
• /
• 2016

Background: The induction of cellular defensive genes such as phase II detoxifying and antioxidant enzymes is a highly effective strategy for protection against carcinogenesis as well as slowing cancer development. Transcription factor Nrf2 (nuclear factor E2-related factor 2) is responsible for activation of phase II enzymes induced by natural chemopreventive compounds. Methods: Red ginseng oil (RGO) was extracted using a supercritical $CO_2$ extraction system and chemical profile of RGO was investigated by GC/MS. Effects of RGO on regulation of the Nrf2/antioxidant response element (ARE) pathway were determined by ARE-luciferase assay, western blotting, and confocal microscopy. Results: The predominant components of RGO were 9,12-octadecadienoic acid (31.48%), bicyclo[10.1.0] tridec-1-ene (22.54%), and 22,23-dihydrostigmasterol (16.90%). RGO treatment significantly increased nuclear translocation of Nrf2 as well as ARE reporter gene activity, leading to upregulation of heme oxygenase-1 and NAD(P)H:quinone oxidoreductase 1. Phosphorylation of the upstream kinases such as apoptosis signal-regulating kinase (ASK)1, mitogen-activated protein kinase (MAPK) kinase (MKK)4/7, c-Jun N-terminal kinase (JNK), and p38 MAPK were enhanced by treatment with RGO. In addition, RGO-mediated Nrf2 expression and nuclear translocation was attenuated by JNK inhibitor SP600125 and p38 MAPK inhibitor SB202190. Conclusion: RGO could be used as a potential chemopreventive agent, possibly by induction of Nrf2/ARE-mediated phase II enzymes via ASK1-MKK4/7-JNK and p38 MAPK signaling pathways.

• The Korea Journal of Herbology
• /
• v.30 no.6
• /
• pp.7-15
• /
• 2015

Objectives : Rosa laevigata Michx. has been used for the treatment of renal disease in traditional Korean medicine. In this study, we investigated cytoprotective effect of R. laevigata water extract (RLE) against oxidative stress induced by arachidonic acid (AA) + iron.Methods : To evaluate the protective effects of RLE against AA + iron-induced oxidative stress in HepG2 cell, cell viability and changes on apoptosis-related proteins were assessed by MTT and immunoblot analyses. The effects of RLE on reduced glutathione level, production of reactive oxygen species and mitochondrial membrane potential were also monitored. Furthermore, to verify underlying molecular mechanism, NF-E2-related factor 2 (Nrf2) was examined by immunoblot analysis. Additionally, Nrf2 transactivation and its downstream target genes expression were also determined by reporter gene and realtime RT-PCR analyses.Results : RLE pretreatment (30-300 μg/ml) prevented cells from AA + iron-mediated cell death in a concentration dependent manner. In addition, 100 μg/ml RLE inhibited AA + iron-induced glutathione depletion, reactive oxygen species production and mitochondrial dysfunction. RLE accumulated nuclear Nrf2 and also transactivated Nrf2, which was evidenced by antioxidant response element- and glutathione S-transferase A2-driven luciferase activities and mRNA level of glutamate-cysteine ligase catalytic subunit, NAD(P)H:quinone oxidoreductase 1 and sestrin 2. Moreover, protective effect of RLE against AA + iron was abolished in Nrf2 knockout cells.Conclusions : These results indicate that RLE has the ability to protect hepatocyte against oxidative stress through Nrf2 activation.

• Korean Journal of Food Science and Technology
• /
• v.49 no.6
• /
• pp.617-624
• /
• 2017

Chocolate, one of the most popular confectioneries in the world, is known for its aromatic flavor and high antioxidant activities. In this study, we investigated the effects of fermentation with commercially available lactic acid bacteria, ABT-5, on the flavor and antioxidant activities of dark chocolate. During 24 h fermentation, pH decreased from 5.52 to 3.97 and total acidity increased from 0.51 to 1.85%, whereas total polyphenol and flavonoid contents as well as DPPH and ABTS radical scavenging activities remained unchanged. Furthermore, compared with control HepG2 cells treated with unfermented dark chocolate, those treated with the fermented dark chocolate showed significantly lower levels of reactive oxygen species and higher viability under $H_2O_2-induced$ oxidative stress. Finally, GC-MS and headspace GC-MS analysis detected 4-hydroxy-2,5-dimethyl-3(2H)-furanone and 2-furanmethanol, known to enhance flavor, in the fermented dark chocolate. Collectively, these results suggest that ABT-5-fermented dark chocolate could be utilized for developing value-added dark chocolate products.

• Journal of Ginseng Research
• /
• v.23 no.1 s.53
• /
• pp.44-49
• /
• 1999

Cu/Zn superoxide dismutase (SOD1) is a protective enzyme responsible for the dismutat ion of superoxide radicals within the cell by converting superoxide radicals to oxygen and hydrogen peroxide, which is in turn changed to oxygen and water by catalase. Previously, we reported that the panaxadiol (PD) and its ginsenoside $Rb_2$ induced the expression of SOD1 gene through AP2 binding site and its induction. Here, we examined the effect of subfractions of panaxadiol ginsenosides, which were extracted from different parts of ginseng root that possess various ratios of panaxadiol to panaxatriol, on the induction of SOD1 gene expression. To explore this possibility, the upstream regulatory region of SOD1 was linked to the chloramphenicol acetyl transferase (CAT) structural gene and introduced into human hepatoma HepG2 cells. We observed that the transcriptional activation of SOD1 was proportional to the contents ratio of panaxadiol ginsensides. Consistent with this results, the total extract portion prepared from the finely-hairy root, which contains the higher ratio of panaxadiol to panaxatriol about 2.6, increased the SODl transcription about 3 fold. This results suggest that the panaxadiol fraction could induce the SOD1 and total extract of the ginseng finely-hairy root would be a useful material as a functional food for the SOD1 inducer.

• Nutrition Research and Practice
• /
• v.4 no.2
• /
• pp.93-98
• /
• 2010

Our previous study demonstrated that methanolic extract of Chrysanthemum zawadskii Herbich var. latilobum Kitamura (Compositae) has the potential to induce detoxifying enzymes such as NAD(P)H:(quinone acceptor) oxidoreductase 1 (EC 1.6.99.2) (NQO1, QR) and glutathione S-transferase (GST). In this study we further fractionated methanolic extract of Chrysanthemum zawadskii and investigated the detoxifying enzyme-inducing potential of each fraction. The fraction (CZ-6) shown the highest QR-inducing activity was found to contain (+)-(3S,4S,5R,8S)-(E)-8-acetoxy-4-hydroxy-3-isovaleroyloxy-2-(hexa-2,4-diynyliden)-1,6-dioxaspiro [4,5] decane and increased QR enzyme activity in a dose-dependent manner. Furthermore, CZ-6 fraction caused a dose-dependent enhancement of luciferase activity in HepG2-C8 cells generated by stably transfecting antioxidant response element-luciferase gene construct, suggesting that it induces antioxidant/detoxifying enzymes through antioxidant response element (ARE)-mediated transcriptional activation of the relevant genes. Although CZ-6 fraction failed to induce hepatic QR in mice over the control, it restored QR activity suppressed by $CCl_4$ treatment to the control level. Hepatic injury induced by $CCl_4$ was also slightly protected by pretreatment with CZ-6. In conclusion, although CZ-6 fractionated from methanolic extract of Chrysanthemum zawadskii did not cause a significant QR induction in mice organs such as liver, kidney, and stomach, it showed protective effect from liver damage caused by $CCl_4$.

• Molecules and Cells
• /
• v.45 no.7
• /
• pp.465-478
• /
• 2022

MicroRNAs (miRNAs) are a class of small non-coding RNAs that regulate the expression of target messenger RNA (mRNA) complementary to the 3' untranslated region (UTR) at the post-transcriptional level. Hsa-miR-422a, which is commonly known as miRNA derived from transposable element (MDTE), was derived from short interspersed nuclear element (SINE). Through expression analysis, hsa-miR-422a was found to be highly expressed in both the small intestine and liver of crab-eating monkey. AT-Rich Interaction Domain 5 B (ARID5B) was selected as the target gene of hsa-miR-422a, which has two binding sites in both the exon and 3'UTR of ARID5B. To identify the interaction between hsa-miR-422a and ARID5B, a dual luciferase assay was conducted in HepG2 cell line. The luciferase activity of cells treated with the hsa-miR-422a mimic was upregulated and inversely downregulated when both the hsa-miR-422a mimic and inhibitor were administered. Nuclear factor erythroid-2 (NF-E2) was selected as the core transcription factor (TF) via feed forward loop analysis. The luciferase expression was downregulated when both the hsa-miR-422a mimic and siRNA of NF-E2 were treated, compared to the treatment of the hsa-miR-422a mimic alone. The present study suggests that hsa-miR-422a derived from SINE could bind to the exon region as well as the 3'UTR of ARID5B. Additionally, hsa-miR-422a was found to share binding sites in ARID5B with several TFs, including NF-E2. The hsa-miR-422a might thus interact with TF to regulate the expression of ARID5B, as demonstrated experimentally. Altogether, hsa-miR-422a acts as a super enhancer miRNA of ARID5B by collaborating with TF and NF-E2.

• Journal of Microbiology and Biotechnology
• /
• v.28 no.8
• /
• pp.1376-1383
• /
• 2018

The hepatitis B virus (HBV) envelope contains small (S), middle (M), and large (L) proteins. PreS1 of the L protein contains a receptor-binding motif crucial for HBV infection. This motif is highly conserved among 10 HBV genotypes (A-J), making it a potential target for the prevention of HBV infection. In this study, we successfully generated a neutralizing human monoclonal antibody (mAb), 1A8 (IgG1), that recognizes the receptor-binding motif of preS1 using a phage-displayed human synthetic Fab library. Analysis of the antigen-binding activity of 1A8 for different genotypes indicated that it can specifically bind to the preS1 of major HBV genotypes (A-D). Based on Bio-Layer interferometry, the affinity ($K_D$) of 1A8 for the preS1 of genotype C was 3.55 nM. 1A8 immunoprecipitated the hepatitis B virions of genotypes C and D. In an in vitro neutralization assay using HepG2 cells overexpressing the cellular receptor sodium taurocholate cotransporting polypeptide, 1A8 effectively neutralized HBV infection with genotype D. Taken together, the results suggest that 1A8 may neutralize the four HBV genotypes. Considering that genotypes A-D are most prevalent, 1A8 may be a neutralizing human mAb with promising potential in the prevention and treatment of HBV infection.

• Preventive Nutrition and Food Science
• /
• v.8 no.4
• /
• pp.356-364
• /
• 2003

A methanol extract from seeds of Paeonia lactiflora (Paeoniaceae, peony) was found to possess different antiproliferative activities against four different human cancer cell lines: Hela, MCF-7, HepG2 and HT-29. Furthermore, five different methanol (20, 40, 60, 80 and 100 % MeOH) fractions obtained by fractionation of the methanol extract of the seeds on a Diaion HP-20 column exhibited differential antiproliferative effects against the above four cancer cell lines. Among five fractions, the 60 % MeOH fraction showed relatively lower antiproliferative activity on MCF-7 estrogen-sensitive breast cancer cell than the other cancer cell lines. Systematic separation of 60% the MeOH fraction by silica gel and Sephadex LH-20 columns led to the isolation of four known stilbenes, trans-resveratrol (1), trans-(+)- $\varepsilon$ -viniferin (2), gnetin H (3) and suffruticosol B (4). The four stilbenes (1∼4) exerted differential biphasic effects on cell proliferation of MCF-7 cells in a similar manner as genistein, a soybean isoflavone used as a positive reference, in the concentration range from 1.0 to 200 $\mu$M. Three stilbenes (1 ∼ 3) weakly stimulated the proliferation of MCF -7 cells at doses below 10 JIM. However, strong antiproliferative effects on MCF-7 cell were exerted by extract 1 at a dose of 200 JIM, and by 2 and 3 at doses above 25 $\mu$M. In contrast, 4 inhibited the proliferation of MCF-7 cell at a dose below 25 $\mu$M, but stimulated cell proliferation at concentrations of 50 and 100 $\mu$M. All four stilbenes (1∼4) stimulated the proliferation of ROS 17/2.8 osteoblast-like cells in the range of 10$^{-10}$ ∼10$^{-1}$ $\mu$M. Compound 1 exhibited especially potent proliferative activity, although its activity was weaker than that of genistein. Additionally, three resveratrol oligomers (2∼4) also exhibited concentration-dependently moderate proliferative activity, but less than that of 1. These results suggest that resveratrol, and its dimer and trimers from the seeds of Paeonia lactiflora may act as a phytoestrogen, but in a somewhat different manner from that of genistein.