• Korean Journal of Medicinal Crop Science
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• v.14 no.6
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• pp.322-328
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• 2006

Green tea is of particular source as it has been found to have strong antioxidant activities. The extracts of green tea during the commercial harvest seasons from April, 2003 to August, 2003 were compared. The purpose of this study was to determine the correlation between the polyphenol content of green teas and its antioxidant activities. The con-tent of total polyphenols was analyzed and several antioxidant testings were performed. The levels of total polyphenols were higher in the green teas (e.g. Woojeon, Sejak) harvested during very early spring and lower in the green teas harvested late(eg. Ipha, Yepcha). In particular, the free radical scavenging, the inhibition of LDL oxidation, the cytoprotective effect and the inhibition of DNA damage were correlated with the total polyphenol contents of green tea extracts harvested early spring such as Woojeon, Sejak and Jungjak. The results obtained here show that all extracts of green teas including purified green tea catechin, GTC, have strong antioxidant activities on oxidative stress in vifrθ. The variation in polyphenol content and antioxidant activities among various types of green tea by the harvesting time may provide critical information for investigators and consumers using tea in purposes of nutrition and chemoprevention.

• Archives of Pharmacal Research
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• v.25 no.5
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• pp.561-571
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• 2002

The action mechanisms of several chemopreventive agents derived from herbal medicine and edible plants have become attractive issues in cancer research. Tea is the most widely consumed beverage worldwide. Recently, the cancer chemopreventive actions of tea have been intensively investigated. It have been demonstrated that the active principles of tea were attributed to their tea polyphenols. Recently, tremendous progress has been made in elucidating the molecular mechanisms of cancer chemoprevention by tea and tea polyphenols. The suppression of various tumor biomarkers including growth factor receptor tyrosine kinases, cytokine receptor kinases, P13K, phosphatases, ras, raf, MAPK cascades, NㆍFB, IㆍB kinase, PKA, PKB, PKC, c-jun, c-fos, c-myc, cdks, cyclins, and related transducing proteins by tea polyphenols has been studied in our laboratory and others. The IㆍB kinase (IKK) activity in LPS-activated murine macrophages (RAW 264.7 cells) was found to be inhibited by various tea polyphenols including (-) epigallocatechin-3-gallate (EGCG), theaflavin (TF-1), theaflavin-3-gal-late (TF-2) and theaflavin-3,3'-digallate (TF-3). TF-3 inhibited IKK activity in activated macrophages more strongly than did the other tea polyphenols. TF-3 inhibited both IKK1 and IKK2 activity and prevented the degradation of IㆍBㆍand IㆍBㆍin activated macrophage cells. The results suggested that the inhibition of IKK activity by TF-3 and other tea polyphenols could occur by a direct effect on IKKs or on upstream events in the signal transduction pathway. TF-3 and other tea polyphenols blocked phosphorylation of IB from the cytosolic fraction, inhibited NFB activity and inhibited increases in inducible nitric oxide synthase levels in activated macrophage. TF-3 and other tea polyphenols also inhibited strongly the activities of xanthine oxidase, cyclooxygenase, EGF-receptor tyrosine kinase and protein kinase C. These results suggest that TF-3 and other tea polyphenols may exert their cancer chemoprevention through suppressing tumor promotion and inflammation by blocking signal transduction. The mechanisms of this inhibition may be due to the blockade of the mitogenic and differentiating signals through modulating EGFR function, MAPK cascades, NFkB activation as wll as c-myc, c-jun and c-fos expression.

• Journal of Preventive Medicine and Public Health
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• v.33 no.4
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• pp.383-392
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• 2000

Objective : We have reviewed the potential cancer preventive and other relevant properties of Panax ginseng C. A. Meyer, which has been traditionally used as a natural tonic in oriental countries. Data identification and study selection: Publications on Panax ginseng and its relation to cancer were obtained from the Medline database (1983-2000) and by checking reference lists to find earlier reports. The reports cover experimental models and human studies on cancer-preventive activity, carcinogenicity and other beneficial or adverse effects. In addition, possible mechanisms of chemoprevention by ginseng were also considered. Results : Published results from a cohort and two case-control studies in Korea suggest that the intake of ginseng may reduce the risk of several types of cancer. When ginseng was tested in animal models, a reduction in cancer incidence and multiplicity at various sites was noted. Panax ginseng and its chemical constituents have been tested for their inhibiting effect on putative carcinogenesis mechanisms (e.g., cell proliferation and apoptosis, immunosurveillance, angiogenesis); in most experiments inhibitory effects were found. Conclusion : While Panax ginseng C. A. Meyer has shown cancer preventive effects both in experimental models and in epidemiological studies, the evidence is currently not conclusive as to its cancer-preventive activity in humans. The available evidence warrants further research into the possible role of ginseng in the prevention of human cancer and carcinogenesis.

• Journal of Ginseng Research
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• v.39 no.1
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• pp.14-21
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• 2015

Background: Colorectal cancer is a leading cause of cancer-related death, and inflammatory bowel disease is a risk factor for this malignancy. We previously reported colon cancer chemoprevention potential using American ginseng (AG) in a xenograft mice model. However, the nude mouse model is not a gut-specific colon carcinogenesis animal model. Methods: In this study, an experimental colitis and colitis-associated colorectal carcinogenesis mouse model, chemically induced by azoxymethane/dextran sodium sulfate (DSS) was established and the effects of oral AG were evaluated. The contents of representative ginseng saponins in the extract were determined. Results: AG significantly reduced experimental colitis measured by the disease activity index scores. This suppression of the experimental colitis was not only evident during DSS treatment, but also very obvious after the cessation of DSS, suggesting that the ginseng significantly promoted recovery from the colitis. Consistent with the anti-inflammation data, we showed that ginseng very significantly attenuated azoxymethane/DSS-induced colon carcinogenesis by reducing the colon tumor number and tumor load. The ginseng also effectively suppressed DSS-induced proinflammatory cytokines activation using an enzyme-linked immunosorbent assay array, in which 12 proinflammatory cytokine levels were assessed, and this effect was supported subsequently by real-time polymerase chain reaction data. Conclusion: AG, as a candidate of botanical-based colon cancer chemoprevention, should be further investigated for its potential clinical utility.

• Korean Journal of Pharmacognosy
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• v.38 no.1
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• pp.95-99
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• 2007

In order to find novel cancer chemopreventive agents, quinone reductase (QR) inductive activity of methanol extract of herbal medicines was examined using murine hepatoma, hepa1c1c7 cells. QR has been used as an anticarcinogenic marker enzyme in cancer chemoprevention study. The methanol extract of Alpinia officinarum (Zingiberace) showed showed significantly strong quinone reductase inductive activity compared to the control group. The methanol extract of Alpinia officinarum was successively fractionated with various solvents according to polarity. Hexane, ethyl acetate, buthanol and water fractions were obtained and theirs activities were assessed. The QR inductive effect was moved to the ethyl acetate fraction and was highly increased. The CD (concentration required to double the specific activity of QR) value of ethyl acetate fraction was 8.6 ${\mu}g/mL$. Alpinia officinarum also showed strong antioxidant activity. These results suggest that Alpinia officinarum can be developed as cancer chemopreventive agent.

• Korean Journal of Plant Resources
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• v.30 no.6
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• pp.640-646
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• 2017

In this study, we elucidated anti-cancer activity and potential molecular mechanism of 70% ethanol extracts from Taxilli Ramulus (Taxillus chinensis (DC.) Danser) (TR-E70) against human colorectal cancer cells. Anti-cell proliferative effect of TR-E70 was evaluated by MTT assay. The effect of TR-E70 on the expression of cyclin D1 in the protein and mRNA level was evaluated by Western blot and RT-PCR, respectively. TR-E70 suppressed the proliferation of human colorectal cancer cell lines, HCT116 and SW480. Although TR-E70 decreased cyclin D1 expression in protein and mRNA level, decreased level of cyclin D1 protein by TR-E70 more dramatically occurred than that of cyclin D1 mRNA. Cyclin D1 downregulation by TR-E70 was attenuated in presence of MG132. In addition, TR-E70 phosphorylated threonine-286 (T286) of cyclin D1. TR-E70-mediated cyclin D1 degradation was blocked in presence of LiCl as an inhibitor $GSK3{\beta}$ but not PD98059 as an ERK1/2 inhibitor and SB203580 as a p38 inhibitor. Our results suggest that TR-E70 may downregulate cyclin D1 as one of the potential anti-cancer targets through $GSK3{\beta}$-dependent cyclin D1 degradation. From these findings, TR-E70 has potential to be a candidate for the development of chemoprevention or therapeutic agents for human colorectal cancer.

• Natural Product Sciences
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• v.21 no.3
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• pp.210-218
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• 2015

The antioxidant activity of white ginseng was not recorded in Korea Functional Food Code, while its activity of red ginsengs was recorded. The aim of this study was to evaluate the antioxidant and hepato protective effect of different ginsengs in H₂O₂-treated HepG2 cells. White and red ginseng were prepared from longitudinal section of the same fresh ginseng (4-year old). The whole parts of white and red ginsengs were separately extracted with 70% ethanol and distilled water respectively, at 70 ℃ to obtain therapeutic ginseng extracts namely, WDH (distilled water extract of white ginseng), WEH (70% ethanol extract of white ginseng), RDH (distilled water extract of red ginseng) and REH (70% ethanol extract of red ginseng). In this work, we have investigated the DPPH, hydroxyl radical, Fe²⁺-chelating activity, intracellular ROS scavenging capacity and lipid peroxidation of different ginsengs. All these extracts showed a dose dependent free-radical scavenging capacity and a ROS generation as well as lipid peroxidation was significantly reduced by treatment with bioactive extracts of white ginsengs (WDH) than red ginsengs. Additionally, white ginseng extracts (WDH) has dramatically increased intracellular antioxidant enzyme activities like superoxide dismutase and catalase in H₂O₂-treated HepG2 cells. All these results explain that administration of white ginseng is useful as herbal medicine than red ginseng for chemoprevention of liver damage.

• Journal of Marine Bioscience and Biotechnology
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• v.1 no.2
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• pp.71-75
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• 2006

The effect of protein extract from Asterina pectinifera on proliferation of human breast cancer cells and activities of cytochrome P450 1A1 and ornithine decarboxylase was tested. Protein extract from Asterina pectinifera inhibited the growth of both estrogen-dependent MCF-7 and estrogen-independent MDA-MB-231 human breast cancer cells. Cytochrome P450 1A1 activity was significantly inhibited by the protein extract from Asterina pectinifera at concentrations of 80 (p<0.05), 120 (p<0.01) and $160{\mu}g/m{\ell}$ (p<0.01). The extract inhibited induction of ornithine decarboxylase by 12-O-tetradecanoylphorbol-13-acetate, a key enzyme of polyamine biosynthesis, which is enhanced in breast tumor promotion. Therefore, Asterina pectinifera is worth further investigation with respect to breast cancer chemoprevention or therapy.

• YAKHAK HOEJI
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• v.45 no.1
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• pp.101-107
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• 2001

Green tea catechins (GTC) and its major component, (-)-epigallocatechin gallate (EGCG) were studied for their protective effects against reactive oxygen species (ROS)-induced oxidative stress. GTC and EGCG skewed the strong antioxidative effects on the lipid peroxidation of ethyl linolate with Fenton's reagent and free radical scavenging effect to DPPH radical generation. They also protected $H_2O$$_2$- or KO$_2$-induced cytotoxicity in CHL cells or mouse splenocytes. These results indicate that GTC and EGCG are capable of protecting the lipid peroxidation, flee radical generation and cytotoxicity induced by ROS. The mechanism of inhibition in ROS-induced cytotoxicity may be due to their antiofidative and free radical scavenging properties. Therefore, GTC and EGCG may be useful chemopreventive agents by protecting the free radical generation which are involved in cancer and aging.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.7
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• pp.2679-2683
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• 2015

Background: Phenethyl isothiocyanate (PEITC), the most comprehensively studied aromatic isothiocyanate, has been shown to act as an anti-cancer agent mainly through modulation of biotransformation enzymes responsible for metabolizing carcinogens in the human body. Humans are often exposed to carcinogenic factors, some of which through the diet, such as polycyclic aromatic hydrocarbon benzo[a]pyrene via the consumption of over-cooked meats. Inhibition of the enzymes responsible for the bioactivation of this carcinogen, for example CYP1A1, the major enzyme required for polycyclic aromatic hydrocarbons (PAHs) bioactivation, is recognized as a chemoprevention strategy. Objective: To evaluate the inhibitory effects of PEITC against benzo[a]pyrene-induced rise in rat liver CYP1A1 mRNA and apoprotein levels. Materials and Methods: Precision cut rat liver slices were treated with benzo[a]pyrene at 1 and $5{\mu}M$ in the presence of PEITC ($1-25{\mu}M$) for 24 hours, followed by determination of CYP1A1 mRNA and apoprotein levels using quantitative polymerase chain reaction and immunoblotting. Results: Findings revealed that PEITC inhibited benzo[a]pyrene-induced rise in rat liver CYP1A1 mRNA in a dose-dependent manner as well as the apoprotein levels of CYP1A. Conclusions: It was demonstrated that PEITC can directly inhibit the bioactivation of benzo[a]pyrene, indicating chemopreventive potential.