• Asian Pacific Journal of Cancer Prevention
• /
• 제13권9호
• /
• pp.4393-4402
• /
• 2012

Colon cancer is the third most common malignant neoplasm in the world and it remains an important cause of death, especially in western countries. The toxic environmental pollutant, 1, 2-dimethylhydrazine (DMH), is also a colon-specific carcinogen. Tannic acid (TA) is reported to be effective against various types of chemically induced toxicity and also carcinogenesis. In the present study, we evaluated the chemopreventive efficacy of TA against DMH induced colon toxicity in a rat model. Efficacy of TA against the colon toxicity was evaluated in terms of biochemical estimation of antioxidant enzyme activities, lipid peroxidation, histopathological changes and expression of early molecular markers of inflammation and tumor promotion. DMH treatment induced oxidative stress enzymes (p<0.001) and an early inflammatory and tumor promotion response in the colons of Wistar rats. TA treatment prevented deteriorative effects induced by DMH through a protective mechanism that involved reduction of oxidative stress as well as COX-2, i-NOS, PCNA protein expression levels and TNF-${\alpha}$ (p<0.001) release. It could be concluded from our results that TA markedly protects against chemically induced colon toxicity and acts plausibly by virtue of its antioxidant, anti-inflammatory and antiproliferative activities.

• 한국환경성돌연변이발암원학회지
• /
• 제18권1호
• /
• pp.1-8
• /
• 1998

Chemoprevention refers to the use of non-toxic chemical agents to prevent the neoplastic development by inhibiting, delaying, or reversing a multi-stage carcinogenesis. The primary goal of chemoprevention research is to identify or produce effective agents and strategies for clinical trials for applications to normal or high risk human populations. A large number of compounds have been tested for their possible chemopreventive activities, and it is of interest to note that many of them are naturally occurring substances. Thus, a variety of plant and vegetable constituents, particularly those included in our daily diet, have been found to possess substantial protective properties against experimental carcinogenesis. These substances, collectively known as dietary phytochemicals, exert their chemopreventive effects by influencing specific step(s) of multi-stage carcinogenesis: some inhibit metabolic activation or enhance detoxification of carcinogens, others interfere with covalent interactions between ultimate eloctrophilic carcinogens and the target cell DNA and still others may exert anti-promoting or anti-progressing effects. Mechanism-based interventions by use of safe dietary phytochemicals may provide one of the most practical and promising cancer chemopreventive strategies.

• 한국환경성돌연변이발암원학회:학술대회논문집
• /
• 한국환경성돌연변이발암원학회 2001년도 Korean Environmental Mutagen Society
• /
• pp.41-42
• /
• 2001

• 생약학회지
• /
• 제32권2호통권125호
• /
• pp.168-174
• /
• 2001

Induction of phase II enzymes is a major mechanism of chemoprevention. The induction levels of quinone reductase (QR) activity in cultured murine hepatoma (Hepa 1c1c7) cells by 80%-methanol extracts of traditional medicinal plants were measured. Among the tested 81 plants, the extracts of Aralia continentalis, Magnolia obovata, and Viscum album were found to induce QR activities over 250%. The maximum induction levels obtained were 401.9%, 270.5%, and 301.8% by treatments of the extracts of A. continentalis $(318\;{\mu}g/ml)$, M. obovata $(53.8\;{\mu}g/ml)$ and V. album $(80.6\;{\mu}g/ml)$, respectively. These QR induction activities were more potent than those of the known QR inducers, t-butylhydroquinone (170.1%) and ${\beta}-naphthoflavone$ (320.0%).

• 한국독성학회:학술대회논문집
• /
• 한국독성학회 2001년도 International Symposium on Dietary and Medicinal Antimutgens and Anticarcinogens
• /
• pp.11-12
• /
• 2001

Selenium is known to have both chemopreventive and therapeutic benefits of cancer. Recent studies have implicated that apoptosis is one of the most plausible mechanism of chemopreventive effects of selenium compounds and tumor invasion is a new factor involved in chemotherapy. In the present study, we demonstrate that Se-methylselenocysteine(MSC), one of the most effective selenium compound sat chemoprevention, induces apoptosis in HL-60 cells and that ROS plays a crucial role in MSC-induced apoptosis.(omitted)

• 한국독성학회:학술대회논문집
• /
• 한국독성학회 2003년도 추계학술대회
• /
• pp.113-113
• /
• 2003

Recently, selenium has been reported to have cancer-preventive properties, although the mechanism is little known. To elucidate the mechanism, we examined the effect of selenomethionine (SeMet) on the functional status of p53. Here we show the activation of p53 tumor suppressor in the presence of SeMet without DNA damage. (omitted)

• 한국환경성돌연변이발암원학회:학술대회논문집
• /
• 한국환경성돌연변이발암원학회 2003년도 추계학술대회
• /
• pp.113-113
• /
• 2003

• Food Science and Biotechnology
• /
• 제17권3호
• /
• pp.613-622
• /
• 2008

Cancer chemopreventive effects can be exerted through the induction of phase II detoxification enzymes and the inhibition of inflammatory responses. In this study, the cancer chemopreventive effects and anti-inflammatory responses of 30 seaweed extracts were examined. The extracts of Dictyota coriacea and Cutleria cylindrica exhibited the high chemoprevention index, having 4.36 and 4.66, respectively. They also activated antioxidant response element at $100\;{\mu}g/mL$ by about 3-fold while did not activate xenobiotic response element. Seven seaweed extracts, Ishige okamurae, Desmarestia ligulata, Desmarestia viridis, Dictyopteris divaricata, D. coriacea, Sargassum horneri, and Sargassum yezoense, showed significant inhibition on nitric oxide (NO) and prostaglandin $E_2$ ($PGE_2$) production in a dose-dependant manner in $5-20\;{\mu}g/mL$. These seaweed extracts could be used as food materials for cancer chemoprevention. D. coriacea could contain potential chemopreventive agents not only that regulate genes via an ARE-dependent mechanism but also prevent the inflammation through inhibition of NO and $PGE_2$ production.

• BMB Reports
• /
• 제41권4호
• /
• pp.328-333
• /
• 2008

A variety of anti-inflammatory agents have been shown to exert chemopreventive activity via targeting of transcription factors such as NF-${\kappa}B$ and AP-1. Lithospermum erythrorhizon (LE) has long been used in traditional oriental medicine. In this study, we demonstrated the inhibitory effects of LE extracts on lipopolysaccharide (LPS)-stimulated production of inflammatory cytokines. As an underlying mechanism of inhibition, LE extracts reduced LPS-induced transactivation of AP-1 as well as NF-${\kappa}B$ in mouse macrophage cells. Electrophoretic mobility shift assays indicated that LE extracts inhibited the DNA binding activities of AP-1 and NF-${\kappa}B$. In addition, phosphorylation of $I{\kappa}B-{\alpha}$ protein was suppressed by LE extracts. Moreover, LE extracts inhibited c-Jun N-terminal kinase and extracellular signal-regulated signaling pathways. Our results suggest that the anti-inflammatory activity of LE extracts may be mediated by the inhibition of signal transduction pathways that normally lead to the activation of AP-1and NF-${\kappa}B$. These inhibitory effects may be useful for chemoprevention of cancer or other chronic inflammatory diseases.

• 한국독성학회:학술대회논문집
• /
• 한국독성학회 2001년도 International Symposium on Dietary and Medicinal Antimutgens and Anticarcinogens
• /
• pp.41-42
• /
• 2001

The chemopreventive effect of tea against 2-amino-l-methyl-6-phenylimidazo［4, 5-b ］pyridine (PhIP)-DNA adduct formation and its mechanism were studied. Rats were exposed to freshly prepared aqueous extracts of green tea (3% w/v) as the sole source of drinking water for 10 days prior to administration with a single dose of PhIP (10 mg/kg body wt) by oral gavage. PhIP-DNA adducts in the liver, colon, heart, and lung were measured using the $^{32}$ P-postlabelling technique.(omitted)