• Food Science and Biotechnology
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• v.16 no.4
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• pp.501-508
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• 2007

Proanthocyanidins (PACs), also named condensed tannins, are polymers of flavan-3-ols such as (+ )-(gallo)catechin and (-)-epi(gallo)catechin. A proper analysis of the PACs, with difficult challenges due to their complex structures, is crucial in studies of cancer chemoprevention. Cancer is a leading cause of mortality around the world. Many experimental studies have shown that dietary PACs are potential chemopreventive agents that block or suppress against multistage carcinogenesis in both in vitro and in vivo models. Cancer chemoprevention by dietary PACs has been shown effective through different mechanisms of action such as antioxidant, apoptosis-inducing, and enzyme inhibitory activities. Good sources of dietary PACs are nuts, fruits, beans, chocolate, fruit juice, red wine, and green tea. The chemopreventive potential of dietary PACs should be considered together with their bioavailability in humans. The safety issues regarding carcinogenesis and gastrointestinal disorder are also reviewed.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.11
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• pp.5701-5708
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• 2012

The aim of the study was to investigate the chemopreventive potential of andrographolide in 7,12-dimethylbenz(a) anthracene (DMBA)-induced hamster buccal pouch carcinogenesis. Oral tumors developed in the buccal pouch of golden Syrian hamsters at a 100% incidence on painting with 0.5% DMBA in liquid paraffin three times a week for 14 weeks. Marked abnormalities in the status of detoxification enzymes, lipid perxodiation and antioxidants were noticed in hamsters treated with DMBA alone. Oral administration of andrographolide at a dose of 50 mg/kg bw to hamsters treated with DMBA not only completely prevented the tumor formation but also restored the status of the above mentioned biomarkers. The present study thus demonstrates the chemopreventive potential of andrographolide in DMBA-induced hamster buccal pouch carcinogenesis, which is probably due to its antioxidant potential as well as modulating effect on xenobiotic metabolising enzymes during DMBA-induced oral carcinogenesis.

• Proceedings of the PSK Conference
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• 2000.10a
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• pp.182.3-183
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• 2000

• Korean Journal of Pharmacognosy
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• v.34 no.2 s.133
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• pp.161-165
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• 2003

Ethanol extract from Thesium chinense Tunczaninov (TCTE) was tested for breast cancer chemopreventive activity by measuring 7,12-dimethylbenz[a]anthracene (DMBA) - induced cytochrome P450 1A1 activity, induction of quinone reductase and glutathione S-transferase, and glutathione level. TCTE significantly inhibited cytochrome P45O 1A1 activity at the concentration of 90 and 150 mg/ml. TCTE induced quinone reductase activity in a dose-dependent manner in a concentration range of 3-150 mg/ml. In addition glutathione S-transferase activity and glutathione level were increased with TCTE in cultured murine hepatoma Hepa1c1c7 cells. These results suggest that TCTE has breast cancer chemopreventive potential by inhibiting cytochrome P45O 1A1 activity, inducing quinone reductase and glutathione S-transferase activities, and increasing GSH level.

• Archives of Pharmacal Research
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• v.29 no.3
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• pp.209-212
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• 2006

We investigated the effect of protein extract of Asterina pectinifera on the activity of 4 enzymes that may playa role in adenocarcinoma of the colon: quinone reductase (QR), glutathione Stransferase (GST), ornithine decarboxylase (ODC), and cyclooxygenase (COX)-2. QR and GST activity increased in HT-29 human colon adenocarcinoma cells increased that had been exposed to 4 concentrations of the protein extract (80, 160, 200, and $240{\mu}g/mL$). Additionally, 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced ODC activity decreased significantly in cells exposed to the extract in concentrations of $160{\mu}g/mL$ (p<0.05), $200{\mu}g/mL$ (p<0.005), and $240{\mu}g/mL$ (p<0.005). TPA-induced COX-2 activity also decreased in cells exposed to extract concentrations of 10, 20, 40, and $60{\mu}g/mL$. COX-2 expression was also inhibited in cells exposed to this extract. These results suggest that this protein extract of A pectinifera has chemopreventive activity in HT-29 human colon adenocarcinoma cells, and therefore, may have the potential to function as a chemopreventive agent in human colorectal cancer.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.9
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• pp.4507-4510
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• 2016

Isothiocyanates are naturally occurring small molecules that are formed from glucosinolate precursors of cruciferous vegetables. Many isothiocyanates, both natural and synthetic, display anti-carcinogenic activity because they reduce activation of carcinogens and increase their detoxification. This minireview summarizes the current knowledge on isothiocyanates and focuses on their role as potential anti-cancer agents.

• Journal of Acupuncture Research
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• v.17 no.1
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• pp.129-142
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• 2000

Gamdutang aqua-acupuncture solution(GAS), Gamdutang water-extracted solution(GWS) and Degamdutang aqua-acupuncture solution(DGAS) were prepared and tested for potential antitumor activities. It was used three biomarkers (quinone reductase, omithine decarboxylase, glutathione) to test chemopreventive potentials of GAS, GWS, DGAS. GAS was potent inducer of quinone reductase activity in Hepalclc7 murine hepatoma cells in culture, whereas GWS is less potent. GAS, GWS and DGAS were significantly induced quinone reductase activity in cultured rat normal liver cell, Ac2F. Glutathione levels were increased about 1.8-fold with GAS, 1.0-1.1 fold with GWS, DGAS in cultured murine hepatoma hepaiclc7 cells. In addition glutathione s-transferase levels were increased with GAS, GWS and DGAS. The effects of GAS, GWS and DGAS were tested on the growth of Acanthamoeba castellanii. Proliferation of Acanthamoeba castellanii was inhibited by GAS, GWS and DGAS at concentradons of $1{\times}$ and $5{\times}$. These results suggest that GAS has chemopreventive potential by inducing quinone reductase and quinone reductase activities, inhibition of ornithine decarboxylase activity, and increasing glutathione levels.

• Journal of Microbiology and Biotechnology
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• v.15 no.1
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• pp.183-187
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• 2005

Abstract The cancer chemopreventive potential of chitosanoligosaccharides was investigated by measuring the induction of quinone reductase and glutathione S-transferase activities and inhibition of cytochrome P450 1A1, 2B1, and 2E1 activities. Chitosanoligosaccharide I (1-${\kappa}$Da${\kappa}$Da) significantly induced glutathione S-transferase activity with a maximal 1.5-fold increase at 500 ${\mu}$g/ml, while chitosanoligosaccharide II (3-${\kappa}$Da${\kappa}$Da) (500 ${\mu}$g/ml) strongly induced quinone reductase (p<0.01) and glutathione S-transferase (p<0.005) activities. The in vitro incubation of rat liver microsomes with chitosanoligosaccharides I and II (2.5, 5, 50, and 500 ${\mu}$g/ml) showed a dose-dependent inhibiton of cytochrome P450 1A1, 2B1, and 2E1 activities. Chitosanoligosaccharide II was a more potent inhibitor of cytochrome P450 2B1 activity than chitosanoligosaccharide I. Accordingly, these findings suggest that chitosanoligosaccharides are potential chemopreventive agents.

• Biomolecules & Therapeutics
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• v.10 no.4
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• pp.287-292
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• 2002

To find new inhibitory effects from oriental drugs, Albizziae root was extracted in methanol and the extracted was stepwisely fractionated by hexane, chloroform, ethylacetate, butanol and water. In cytotoxic effect of Albizziae root fractions against cancer cell lines including human hepatoma cells(HepG2) were investigated. Expecially the butanol fraction exhibited a inhibition effects on the growth of human hepatoma cells(HepG2). It inhibited of HepG2 cells with the value of IC50. The activities of qutathione after B(a)P treatment were markedly decreased than control, but those levels were increased by the treatment of Albizziae root methanol fraction. The activity of glutathione-S-transferase after B(a)P treatment were markedly decreased than control, but those levels were increased by the treatment of Albizziae root methanol traction. Induction of phase II enzymes is a major mechanism of chemoprevention. The induction levels of quinone reductase(QR) activity in cultured murine hepatoma(Hepa IcIc7)cell by methanol extract of Albizziae root were measured. Among the tested tractions, the extracts of butanol were found to induce QR activities over 2.8 fold than control. These results suggest that Albizziae root has chemopreventive Potential by inducing QR activities and GST levels and increasing GSH

• Food Science and Biotechnology
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• v.17 no.3
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• pp.613-622
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• 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.