• Natural Product Sciences
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• 제3권1호
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• pp.29-37
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• 1997

Protein Kinase C (PKC) is generally believed to play a central role in signal transduction, cellular growth control, gene expression, and tumor promotion. And it has been suggested that inhibitors of PKC might play important roles for the prevention and treatment of cancer. In order to investigate the possible inhibitors of PKC from natural products, PKC receptor binding assay was performed using bovine brain particulate as a source of PKC and the amount of $[^3H]Phorbol$ 12,13-dibutyrate (PDBu) bound to PKC was measured in the presence of test materials. Total methanol extracts from 100 kinds of natural products were partitioned into 3 fractions (n-hexane, ethyl acetate and aqueous layer) and their binding ability to the regulatory domain of PKC was evaluated. The ethyl acetate fractions of Morus alba $(roots,\;IC_{50}:\;156.6\;{\mu}g/ml)$, Rehmannia glutinosa $(roots,\;IC_{50}:\;134.3\;{\mu}g/ml)$, Lysimachia foenum-graecum $(roots,\;IC_{50}:\;167.8\;{\mu}g/ml)$, Polygonum cuspidata $(roots,\;IC_{50}:\;157.3\;{\mu}g/ml)$, Cnidium officinale $(aerial\;parts,\;IC_{50}:\;145.2\;{\mu}g/ml)$, and the hexane $(IC_{50}:\;179.3\;{\mu}g/ml)$ and the EtOAc fraction of Symplocarpus nipponicus $(roots,\;IC_{50}:\;155.9\;{\mu}g/ml)$ showed inhibitory activity of $[^3H]PDBu$ binding to PKC.

• Fisheries and Aquatic Sciences
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• 제16권1호
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• pp.1-5
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• 2013

To assess the feasibility of phlorotannins from Eisenia bicyclis as cancer chemopreventative agents, we tested whether they induced quinone reductase (QR) in Hepa1c1c7 cells. The ethyl acetate (EtOAc) soluble fraction obtained from E. bicyclis exhibited a QR induction activity in Hepa1c1c7 cells. Successive column chromatography of the active EtOAc fraction resulted in the isolation of four phlorotannins. Their structures were elucidated using one- and two-dimensional nuclear magnetic resonance spectroscopic techniques and characterized as phloroglucinol (1), dioxinodehydroeckol (2), dieckol (3), and fucofuroeckol-A (4). Among these compounds, fucofuroeckol-A (4) showed moderate QR induction activity, and dioxinodehydroeckol (2) exhibited potent QR induction potency with $2.05{\pm}0.04$ fold induction at a concentration of $50{\mu}M$ compared to the dimethyl sulfoxide solvent-treated control cells. However, phloroglucinol (1) and dieckol (3) exerted no detectable QR induction activity in Hepa1c1c7 cells. These results suggest that dioxinodehydroeckol could serve as a useful cancer chemopreventive chemical.

• Nutritional Sciences
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• 제9권3호
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• pp.145-151
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• 2006

Matrix metalloproteinases (MMP) play an important role in the extracellular matrix (ECM) degradation undetphysiological and pathological conditions. The present study examined the influence of (-)epigallocatechin gallate and quercetin on phorbol-12-myristate 13-acetate (PMA)-induced secretion of MMP-2 and MMP-9, when human umbilical vein endothelial cells (HUVEC) were treated with (-)epigallocatechin gallate and quercetin at supraphysiological concentrations of $25{\mu}mol/L$. No cytotoxicity was observed by MIT assay in response to a treatment with PMA in the presence of (-)epigallocatechin gallate and quercetin. Western blot analysis and gelatin zymography revealed that exposure of HUVEC to PMA enhanced the levels and gelatinolytic activities of pro and active forms of MMP-2 and active form of MMP-9. (-)Epigallocatechin gallate attenuated PMA-stimulated secretion of active forms of MMP-2 and MMP-9 concomitantly with a loss of activities of these enzymes, which was related to the decreased mRNA levels of MMP. Quercetin was more potent than (-)epigallocatechin gallate in alleviating MMP-9 protein secretion and activity with a decrease in MMP-9 mRNA accumulation. Taken together, the results indicated that (-)epigallocatechin gallte and quercetin exhibited inhibitory effects on MMP activity and may qualify as chemopreventive and cardiovascular protective agents.

• Archives of Pharmacal Research
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• 제26권10호
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• pp.832-839
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• 2003

Activated macrophages express inducible isoforms of nitric oxide synthase (iNOS) and cyclooxygenase (COX-2), and produce excessive amounts of nitric oxide (NO) and prostaglandin E$_2$ (PGE$_2$), which play key roles in the processes of inflammation and carcinogenesis. The root of Paeonia lactiflora Pall., and the root cortex of Paeonia suffruticosa Andr., are important Chinese crude drugs used in many traditional prescriptions. 1,2,3,4,6-penta-O-galloyl-$\beta$-D-glucose (PGG) is a major bioactive constituent of both crude drugs. PGG has been shown to possess potent anti-oxidant, anti-mutagenic, anti-proliferative and anti-invasive effects. In this study, we examined the inhibitory effects of 1,2,3,4,6-penta-O-galloyl-$\beta$-D-glucose (PGG) isolated from the root of Paeonia lactiflora Pall. on the COX-2 and iNOS activity in LPS-activated Raw 264.7 cells, COX-1 in HEL cells. To investigate the structure-activity relationships of gallate and gallic acid for the inhibition of iNOS and COX-2 activity, we also examined (-)-epigallocatechin gallate (EGCG), gallic acid, and gallacetophenone. The results of the present study indicated that PGG, EGCG, and gallacetophenone treatment except gallic acid significantly inhibited LPS-induced NO production in LPS-activated macrophages. All of the four compounds significantly inhibited COX-2 activity in LPS-activated macrophages. Among the four compounds examined, PGG revealed the most potent in both iNOS ($IC_{50}$ = 18 $\mu\textrm{g}/mL$) and COX-2 inhibitory activity (PGE$_2$: $IC_{50}$ = 8 $\mu\textrm{g}/mL$ and PGD$_2$: $IC_{50}$ = 12 $\mu\textrm{g}/mL$), respectively. Although further studies are needed to elucidate the molecular mechanisms and structure-activity relationship by which PGG exerts its inhibitory actions, our results suggest that PGG might be a candidate for developing anti-inflammatory and cancer chemopreventive agents.

• Archives of Pharmacal Research
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• 제29권5호
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• pp.354-362
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• 2006

Dietary flavonoids have attracted a great deal of attention as agents for preventing estrogen-related diseases, such as postmenopausal symptoms, and for reducing the risk of estrogen-dependent cancer. Kaempferol is one of the most commonly found dietary phytoestrogen. The aim of this study was to investigate the estrogenic and/or antiestrogenic effect of kaempferol, which can confirm its potency as a preventive agent against estrogen-related diseases. Kaempferol has both estrogenic and antiestrogenic activity, which are biphasic response on estrogen receptor. The estrogenic activity of kaempferol induced via ER-mediated pathway depending on $E_2$ concentration $(\leq\;10^{-12}M)$. Kaempferol $(10^{-5}\;M)$ also caused antiproliferative effect on MCF-7 cell in the presence of $E_2\;(10^{-11}\;M)$ and restored to the addition of excess $E_2\;(10^{-7}\;M)$, which confirms that antiproliferation of kaempferol was induced via ER-dependent pathway. However, at $10^{-4}\;M$, concentration higher than the concentrations at which the estrogenic effects of kaempferol are detected $(10^{-5}\;M)$, kaempferol induced strong antiproliferative effect, but were unaffected by the addition of excess $E_2\;(10^{-7}\;M)$ indicating that kaempferol exerts antiproliferation via ER-independent pathway. In particular, kaempferol blocked the focus formation induced by $E_2$, which confirms that kaempferol might inhibit the malignant transformation caused by estrogens. Therefore, we suggested that kaempferol might regulate a suitable level of estrogenic activity in the body and is expected to have potential beneficial effects in preventing estrogen imbalance diseases (breast cancer, osteoporosis, cardiovascular disease and etc.).

• Archives of Pharmacal Research
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• 제27권10호
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• pp.1043-1047
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• 2004

Thirteen compounds were isolated from the $CH_2Cl_2$ fraction of Machilus thunbergii as phospholipase $C{\Upsilon}1\;(PLC{\Upsilon}1)$ inhibitors. These compounds were identified as nine lignans, two neolignans, and two flavans by spectroscopic analysis. Of these, 5,7-di-O-methyl-3',4'-methylenated (-)-epicatechin (12) and 5,7,3'-tri-O-methyl (-)-epicatechin (13) have not been reported previously in this plant. In addition, seven compounds, machilin A (1), (-)-sesamin (3), machilin G (5), (+)-galbacin (9), licarin A (10), (-)-acuminatin (11) and compound 12 showed dose-dependent potent inhibitory activities against $PLC{\Upsilon}1$ in vitro with $IC_{50}$ values ranging from 8.8 to 26.0 ${\mu}M$. These lignans, neolignans, and flavans are presented as a new class of $PLC{\Upsilon}1$ inhibitors. The brief study of the structure activity relationship of these compounds suggested that the benzene ring with the methylene dioxy group is responsible for the expression of inhibitory activities against $PLC{\Upsilon}1$. Moreover, it is suggested that inhibition of $PLC{\Upsilon}1$ may be an important mechanism for an antiproliferative effect on the human cancer cells. Therefore, these inhibitors may be utilized as cancer chemotherapeutic and chemopreventive agents.

• Preventive Nutrition and Food Science
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• 제19권4호
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• pp.268-273
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• 2014

The induction of detoxification enzymes by benzyl isothiocyanate (BITC) and its synthetic N-acetyl-L-cysteine (NAC) conjugate (NAC-BITC) was examined in Hepa1c1c7 murine hepatoma cells. BITC and NAC-BITC inhibited Hepa1c1c7 cell growth in a dose-dependent manner. Cell growth was 4.5~57.2% lower in Hepa1c1c7 cells treated with $0.1{\sim}1.0{\mu}M$ BITC than in control-treated Hepa1c1c7 cells. The NAC-BITC treatment had a similar inhibitory pattern on Hepa1c1c7 cell growth; $0.5{\mu}M$ and $10{\mu}M$ NAC-BITC decreased cell growth by 13.6% and 47.4%, respectively. Treatment of Hepa1c1c7 cells with $0.1{\sim}2.0{\mu}M$ BITC also elicited a dose-response effect on the induction of quinone reductase quinone reductase (QR) activity and QR mRNA expression. Treatment with $1{\mu}M$ and $2{\mu}M$ BITC caused 1.8- and 2.8-fold inductions of QR mRNA, respectively. By comparison, treatment with $1{\mu}M$ and $2{\mu}M$ NAC-BITC caused 1.6-and 1.9-fold inductions of QR mRNA, respectively. Cytochrome P450 (CYP) 1A1 and CYP2E1 induction were lower in $0.1{\sim}2{\mu}M$ BITC-treated cells than in control-treated cells. CYP2E1 activity was 1.2-fold greater in $0.1{\mu}M$ NAC-BITC-treated cells than in control-treated cells. However, the CYP2E1 activity of cells treated with higher concentrations (i.e., $1{\sim}2{\mu}M$) of NAC-BITC was similar to the activity of control-treated cells. Considering the potential of isothiocyanatesto prevent cancer, these results provide support for the use of BITC and NAC-BITC conjugates as chemopreventive agents.

• Current Research on Agriculture and Life Sciences
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• 제32권3호
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• pp.119-124
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• 2014

Physalis alkekengi var. francheti Hort. is known as an insecticide and traditional remedy for liver related diseases. Therefore, this study investigated the chemopreventive effects of extracts and several solvent fractions (n-hexane, dichloromethane, n-butanol, water) of Physalis alkekengi var. francheti Hort. First, their cytotoxicity and NQO1 activity were measured using an MTT assay, plus a quinone reductase [NAD(P)H dehydrogenase (quinone); NAD(P)H: (quinone acceptor) oxidoreductase, EC 1.6.99.2]-inducing activity assay was performed using cultured murine hepatoma cells (Hepa1c1c7) and its mutant cells(BpRc1). The reduction of electrophilic quinones by NQO1 is an important detoxification pathway and major mechanism of chemoprevention. When compared with the other solvent soluble fractions with different polarities, the dichloromethane fraction of Physalis alkekengi var. francheti Hort. showed a higher NQO1-inducing activity that was also dose-dependent. Moreover, the dichloromethane fraction of Physalis alkekengi var. francheti Hort. induced ARE-luciferase activities in HepG2-C8 cells that were generated by transfecting the ARE-luciferase gene construct, suggesting the Nrf2-ARE-mediated induction of anti-oxidative enzymes. In conclusion, the dichloromethane-soluble fraction of Physalis alkekengi var. francheti Hort. showed a relatively strong induction of detoxifying enzymes, thereby meriting further study to identify the active components and evaluate their potential as cancer preventive agents.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2019년도 추계학술대회
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• pp.67-67
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• 2019

Vaccinium oldhamii (V. oldhamii) has been reported to exert a variety of the pharmacological properties such as anti-oxidant activity, anti-cancer activity, and inhibitory activity of ${\alpha}$-amylase and acetylcholinesterase. However, the anti-inflammatory activity of V. oldhamii has not been studied. In this study, we aimed to investigate anti-inflammatory activity of the stem extracts from V. oldhamii, and to elucidate the potential mechanisms in LPS-stimulated RAW264.7 cells. Among VOS, VOL and VOF, the inhibitory effect of NO and PGE2 production induced by LPS was highest in VOS treatment. Thus, VOS was selected for the further study. VOS dose-dependently blocked LPS-induced NO and PGE2 production by inhibiting iNOS and COX-2 expression, respectively. VOS inhibited the expression of pro-inflammatory cytokines such as $IL-1{\beta}$, IL-6 and $TNF-{\alpha}$. In addition, VOS suppressed TRAP activity and attenuated the expression of the osteoclast-specific genes such as NFATc1, c-FOS, TRAP, MMP-9, cathepsin K, CA2, OSCAR and ATPv06d2. VOS inhibited LPS-induced $NF-{\kappa}B$ signaling activation through blocking $I{\kappa}B-{\alpha}$ degradation and p65 nuclear accumulation. VOS inhibited MAPK signaling activation by attenuating the phosphorylation of ERK1/2, p38 and JNK. Furthermore, VOS inhibited ATF2 phosphorylation and blocked ATF2 nuclear accumulation. From these findings, VOS has potential to be a candidate for the development of chemopreventive or therapeutic agents for the inflammatory diseases.

• 한국식품과학회지
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• 제37권2호
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• pp.261-267
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• 2005

Phase II 효소계는 자연계에 존재하는 다양한 화학물질과 천연소재들에 의해 유도되며, 이들의 유도는 화학적 발암물질과 그 밖의 여러 가지 독성물질들로부터 생체를 보호하는데 중요한 역할을 한다. 특히, phase II 효소 중 QR은 quinone류 자체에 대한 보호효과가 있고 다른 암예방 효소계와 공통으로 유도되며, 항암 작용이 있는 많은 화합물에 의해 유도되어지기 때문에 암예방 물질 탐색의 지표가 되는 대표적인 효소로 많이 이용된다. 본 연구에서는 제주도에서 자생하는 귤류 중 지각을 이용하여 메탄올추출물을 제조한 후 대표적인 암예방계 효소로 알려진 quinone reductase 및 glutathion S-transferase의 유도 활성을 조사하였다. 우선 QR 및 GST 유도활성 측정에 앞서 각 시료의 Hepa 1c1c7 세포에 대한 독성을 조사하여 시료자체의 세포독성을 관찰하였으며, 이 결과를 바탕으로 QR, GST 유도 활성을 측정할 시 세포독성을 거의 나타내지 않는 각각 시료의 최대 처리 농도를 결정하였다. 총 6개의 지각 분획물 중 mouse 유래 Hepa 1c1c7 세포주에서는 hexane 충과 chloroform 충에서 QR, GST의 활성이 $200{\mu}g/mL$에서 각각 1.8배, 1.5배 이상으로 증가되어 높은 QR 및 GST의 유도활성을 보였다. 따라서 지각의 hexane 층이나 chloroform층에 존재하는 높은 QR및 GST의 유도활성이 나타나는 물질을 분리 정제하여 앞으로 계속적인 연구가 진행되어야 할 것이다.