• Environmental Mutagens and Carcinogens
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• v.18 no.1
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• pp.1-8
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• 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.

• Environmental Mutagens and Carcinogens
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• v.19 no.1
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• pp.56-62
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• 1999

Resveratrol (3,5,4'-trihydroxy-trans-stilbene) has been considered to be as one of major antioxidants present in grapes responsible for beneficial effects of red wine consumption on coronary heart disease. This triphenolic stilbene has been suggested as a potential cancer chemopreventive agent based on its striking inhiitory effects on diverse cellular events associated with tumor initiation, promotion, and progression. The compound has strong antioxidative and anti-inflammatory activities which amy contribute to its chemopreventive/chemoprotective properties. In the present work, we have found that resveratrol reduces viability and DNA synthesis capability of cultured human promyelocytic leukemia (HL-60) cells. Likewise, the viability of human breast cancer cell line, MCF-7 was reduced by resveratrol treatment. The growth inhibitory and antiproliferative properties of resveratrol appear to be associated with its induction of apoptotic cell death as determined by morphological and ultrastructural changes, agarose gel electrphoretic analysis of internucleosomal DNA fragmentation, and in situ terminal end-labeling of fragmented DNA (TUNEL). This compound also inhibited the phorbol ester-induced expression of cyclooxygenase-2 (COX-2) protein in immortalized human mammary epithelial MCF-10A cells. These results suggest that resveratrol has the promising cancer therapeutic/chemopreventive potential.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.3
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• pp.521-526
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• 2002

A number of experimental and epidemiological studies have implicated that antiestrogenic effects of estrogen-like compounds in legumes and plant seeds are responsible for lowering breast cancer risk in human. However, few studies have been conducted to illustrate the possible chemopreventive effects of Korean traditional food materials. This study was performed to determine the cytotoxic and apoptotic effects of yellow soybeans, black soybeans and brown rice extracts on hormone-dependent and hormone-independent human breast cancer cells. Methanol-or acetone-soluble fractions of soybeans or brown rice were incubated with hormone-dependent cells (MCF-7) or hormone-independent cells (MDA-MB-231). Cell cytotoxicity was measured by MTT assay at 24, 48 and 72 hrs of incubation. Apoptotic effects of these extracts toward breast cancer cells were also determined at 48 hrs of incubation by measuring DNA fragmentation. Results indicated that the acetone-soluble fraction of brown rice exerted strongest cytotoxic effect on MCF-7 ceIls, although other fractions also reduced the number of viable MCF-7 cells after 48 hrs of incubation. Both acetone and methanol soluble fractions of all samples exerted a significant cytotoxicity towards MDA-MB-231 cells after 24 hrs of incubation, and acetone and methanol soluble fractions of brown rice were especially effective in these cells. At 48 hrs of incubation, methanol fractions of all three samples induced apopotosis of MDA-MB-231 cells. These results indicate methaol or acetone soluble fractions of yellow soybeans, black soybeans and brown rice induce cytotoxicity in both hormone-dependent and hormone-independent breast cancer cells. Therefore, possible mechanisms of cell cytotoxicity do not necessarily include antiestrogenic effects of soybean or brown rice extract. A possible anticarcinogenic effect of brown rice methanol-soluble fraction may mediated through their apoptotic effect. Further studies are requried to elucidate responsible compounds and mechanisms involved in observed anticarcinogenesis.

• Journal of Life Science
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• v.22 no.12
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• pp.1658-1664
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• 2012

Conjugated linoleic acid (CLA) exhibits several beneficial biological activities including anticarcinogenesis and body-fat reduction. Now, we report that CLA ameliorated the oxidative stress in rat cardiomyoblast cells, H9c2, treated with hydrogen peroxide ($H_2O_2$). Cells were cultured in DMEM/F-12 media at $37^{\circ}C$ with humidified atmosphere of 5% $CO_2$. The cells, cultured for 48 hrs, were seeded at a density $3.5{\times}10^3$ cell/well in a 24 well-plate and incubated for 24 hr. Using these cells, two experiments were performed: the cytotoxicity test of CLA (10, 20, 30, 40, and $50{\mu}Ms$), and the oxidative stress amelioration test of CLA (20 and $50{\mu}Ms$) against cells treated with $H_2O_2$ (10 and 50 ${\mu}Ms$) for 1 and 2 hrs. CLA enhanced the growth of H9c2 cells at any concentrations of CLA and at any incubation times (up to 6 days), indicating that CLA acts as a growth stimulant. No protective effect of CLA (20 and $50{\mu}Ms$) was seen in cells treated $50{\mu}M$ $H_2O_2$ for 1 and 2 hr, but these CLA concentrations ameliorated (p<0.05) the adverse effect of $10{\mu}M$ $H_2O_2$ in cells treated for 1 hr. These CLA concentrations significantly (p<0.05) reduced the proportion of apoptotic cells, relative to control cells. These results suggest that CLA protected H9c2 cells from the oxidative stress of $H_2O_2$ through the suppression of cell apoptosis and could be a useful compound for the prevention of cardiac diseases caused by oxidative stress.