• Archives of Pharmacal Research
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• v.22 no.6
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• pp.559-564
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• 1999

In order to discover new cancer chemopreventive agents from natural or synthetic products, a structurally diverse class of chemopreventive agents was evaluated using in vitro biomarker of inhibition of 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced ornithine decarboxylase (ODC) activity in cultured mouse epidermal 308 (ME)308 cells. As a results, apigenin, benzylisothiocyanate, curcumin, diallyl disulfide, N-(4-hydroxyphenyl)retinamide (4-HPR), menadione, miconazole, nordihydroguaiaretic acid (NDGA) and phenethyl isothiocyanate showed potent inhibitory effects in this process. A chemically diverse group of compounds was included in the evaluation, such as flavonoids, retinoids, isothiocyanates, sulfur-containing compounds and phenolic antioxidant compounds. These data are suggestive to understand the cancer chemopreventive potential mediated by these substances.

• Korean Journal of Pharmacognosy
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• v.30 no.3
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• pp.261-268
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• 1999

Lonicerae flos aqua-acupuncture solution (LFAS) and Lonicerae flos water-extracted solution (LFWS) were prepared and tested for chemopreventive potentials. Three biomarkers [quinone reductase (QR), ornithine decarboxylase (ODC), glutathione(GSH)] were used to test chemopreventive potential of LFAS. LFAS was potent inducer of QR activity in Hepa1c1c7 murine hepatoma cells, whereas LFWS is less potent. LFAS and LFWS were also induced QR activities in cultured human hepatoma Hep3B cells. The effect of LFAS and LFWS were tested on the growth of Acanthamoeba castellanii. Proliferation of Acanthamoeba castellanii was inhibited by LFAS and LFWS at concentrations of $0.1{\times},\;0.5{\times}\;1{\times},\;and\;3{\times}.$ In addition, GSH levels were increased about 2-fold with LFAS and 1.5-fold with LFWS in cultured murine hepa1c1c7 cells. LFAS and LFWS were also shown to increase GSH levels in human Hep3B cells. These results suggest that LFAS has chemopreventive potential by inducing QR activity, inhibition of ODC activity and increasing GSH levels.

• Archives of Pharmacal Research
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• v.24 no.1
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• pp.16-20
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• 2001

2-(Allylthio)pyrazine derivatives were designed as a novel cancer chemopreventive agent that functions through selective inhibtion of cytochrome P-450 and induction of phase 11 enzymes involved in the detoxification of carcinogens. A practical preparation method of 2-(allylthio) pyrazine derivatives was established by the reaction of 2-mercaptopyrazine and allylbromides in the presence of a catalytic antioxidant, DABCO (1,4-diazabicyclo[2,2,2] octane), in dimethyl-formamide at below $50^{\circ}C$.

• Journal of Microbiology and Biotechnology
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• v.14 no.1
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• pp.158-161
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• 2004

Scenedesmus spp. were cultured for 51 days in newly developed medium, KEP I (Kim and Ecopeace: initials of corresponding author and environmental company) made with Bacterio-Mineral-Water (3%, v/v) that had been bio-reacted with swine urine medium to 10% (v/v) Bold's Basal medium, and investigated for cancer chemopreventive potential by measuring the induction of quinone reductase (QR), glutathione S-transferase (GST), and reduced glutathione (GSH), and inhibition of cytochrome P450 (CYP) 1A1 activity. The activitives of QR and GST of Scenedesmus spp. cultured in KEP I medium were increased by 3.0-fold and 1.5-fold, respectively. However, Scenedesmus spp. cultured in control medium (CT) increased the activitives of QR and GST by 1.8-fold and 1.3-fold, respectively. Scenedesmus spp. in KEP I medium strongly inhibited CYP 1Al activity. These results show that Scenedesmus spp. in KEP I medium has cancer chemopreventive potential and may be a candidate for further development as a chemopreventive agent.

• YAKHAK HOEJI
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• v.44 no.3
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• pp.283-292
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• 2000

Angelicae gigantis Radix aqua-acupuncture solution (AGRAS) and Angelicae gigantis Radix water-extracted solution (AGRWS) were prepared and tested for their organ toxicities and chemopreventive potentials. The organ-toxicity of AGRAS to male ICR mice was studied by the measurements of glutamic oxaloacetic transaminase (GOT), glutamic pyruvate transaminase (GPT), lactate dehydrogenase (LDH) and alkaline phosphatase (ALP-s) activities after injection of AGRAS for 7 days. The activities of GOT GPT and LDH were decreased, but the activity of ALP-s was not changed with AGRAS. When AGRAS was administered once daily for 10 days before the tumor implantation, AGRAS exerted antitumor activity by inhibiting the growth of Ehrich ascites tumor cells (EATC) in viva. The inductions of quinone reductase (QR), glutathione (GSH) and glutathione S-transferase (GST) and inhibition of polyamine metabolism were tested for the chemopreventive potentials of AGRAS and AGRWS. AGRAS was potent inducer of QR activity in murine hepatoma Hepalclc7 cells. In cultured rat Ac2F cells, AGRAS was also significantly induced QR activity GSH levels were increased about 1.3 fold with AGRAS. In addition the activity of GST was increased about 2.5 fold with AGRAS at the concentration of $0.1{\;}{\times}{\;}$. The effects of AGRAS and AGRWS were tested on the growth of Acanthamoeba castellanii. Proliferation of Acanthamoeba castellanii in a broth medium was inhibited by AGRAS and AGRWS at the concentration of $1{\;}{\times}{\;}and{\;}5{\;}{\times}{\;}$, respectively: These results suggest that AGRAS has chemopreventive potential by inducing QR activity increasing GSH and GST levels and inhibition of polyamine metabolism.

• Journal of Digestive Cancer Research
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• v.4 no.2
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• pp.64-76
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• 2016

The step-wise process of colorectal carcinogenesis from aberrant crypt foci, adenoma to adenocarcinoma, is relatively suitable for chemopreventive intervention. Accumulated evidences have revealed that maintaining an undifferentiated state (stemness), inflammation, and oxidative stress play important roles in this colon carcinogenesis process. However, appropriate molecular targets that are applicable to chemopreventive intervention regarding those three factors are still unclear. In this review, we summarized appropriate molecular targets by identification and validation of the prospective targets from a comprehensive overview of data that showed colon cancer preventive effects in clinical trials, epidemiological studies and basic research. We first selected a study that used aspirin, statins and metformin from FDA approved drugs, and epigallocatechin-gallate and curcumin from natural compounds as potential chemopreventive agents against colon cancer because these agents are considered to be promising chemopreventive agents. Experimental and observational data revealed that there are common target molecules in these potential chemopreventive agents: T-cell factor/lymphoid enhancer factor (TCF/LEF), nuclear factor-&B (NF-κB) and nuclear factor-erythroid 2-related factor 2(NRF2). Moreover, these targets, TCF/LEF, NF-κB and NRF2, have been also indicated to suppress maintenance of the undifferentiated state, inflammation and oxidative stress, respectively. In the near future, novel promising candidate agents for colon cancer chemoprevention could be identified by integral evaluation of their effects on these three transcriptional activities.

• Journal of Microbiology and Biotechnology
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• v.17 no.8
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• pp.1227-1235
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• 2007

Lactic acid bacteria (LAB) provide several potential health and nutritional benefits, including improving the nutritional value of food, controlling serum cholesterol levels, and controlling some types of cancer. Numerous in vitro, in vivo, human, and epidemiological studies have provided evidence of the chemopreventive effects of LAB on colon, bladder, liver, breast, and gastric cancers. These effects act via diverse mechanisms, including alteration of the gastrointestinal micro flora, enhancement of the host's immune response, and antioxidative and antiproliferative activities. This review discusses the recent progresses on the chemopreventive effects of LAB on specific cancer types and the underlying molecular mechanisms.

• Toxicological Research
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• v.17
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• pp.89-96
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• 2001

Recently, considerable attention has been focused on the role of cyclooxygenase-2 (COX-2) in the carcinogenesis as well as in inflammation. Improperly overexpressed COX-2 has been observed in many types of human cancers and transformed cells in culture. Thus, it is conceivable that targeted inhibition of abnormally or improperly up-regulated COX-2 provides one of the most effective and promising strategies for cancer prevention. A ubiquitous eukaryotic transcription factor, NF-kB is considered to be involved in regulation of COX-2 expression. Furthermore, extracellular-regulated protein kinase and p38 mitogen-activated protein (MAP) kinase appear to be key elements of the intracellular signaling cascades involved in NF-kB activation in response to a wide array of external stimuli. Certain chemopreventive phytochemicals suppress activation of NF-kB by blocking one or more of the MAP kinases, which may contribute to their inhibitory effects on COX-2 induction. One of the plausible mechanisms by which chemopreventive phytochemicals inhibit NF-kB activation involves suppression of degradation of the inhibitory unit I kB, which hampers subsequent translocation of p65, the functionally active subunit of NF-kB.

• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.1071-1076
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• 2001

Chemopreventive activities of polysaccharides from soybeans fermented with either Phellinus igniarius or Agrocybe cylindracea were investigated by measuring the induction of quinone reductase (QR), glutathione S-transferase (GST) activities, and glutathione (GSH) levels in the cell culture along with inhibition of polyamine biosynthesis. The polysaccharides from soybeans fermented with P. igniarius strongly (p<0.005) induced QR activity at all concentrations tested. The extract not only induced GST activity in a dose-dependent manner in the concentration range of 0.1-1.0 mg, but significantly induced GSH revels in cultured Hepa 1c1c7 cells with a maximal 1.4-fold increase at 0.1 mg. The polysaccharides from soybeans fermented with A. cylindracea were effective in inhibiting polyamine metabolism. These results suggest that polysaccharides from soybeans fermented with P. igniarius or A. cylindracea have cancer chemopreventive activities in in vitro models and, therefore, could be considered as potential agents for cancer chemoprevention.

• Natural Product Sciences
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• v.7 no.2
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• pp.38-44
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• 2001

NAD(P)H:quinone reductase (QR), known as DT-diaphorase, is a kind of detoxifying phase II metabolic enzyme catalyzing hydroquinone formation by two electron reduction pathway from quinone type compounds, and thus facilitating excretion of quinoids from human body. With the usefulness of QR induction activity assay system for the modulation of toxicants, in the course of searching for cancer chemopreventive agents from natural products, the methanolic extracts of approximately two hundreds of oriental medicines were primarily evaluated using the induction potential of quinone reductase (QR) activity in cultured murine Hepa1c1c7 cells. As a result, several extracts including Hordeum vulgare, Momordica cochinchinensis, Strychnos ignatii, Houttuynia cordata, and Polygala japonica were found to significantly induce QR activity. In addition, the methylene chloride fraction of H. vulgare, one major dietary food source, showed potent induction of QR activity $(CD=6.4{\mu}g/ml)$. Further study for isolation of active principles from these lead extracts is warranted for the discovery of novel cancer chemopreventive agents.