• Proceedings of the PSK Conference
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• 2002.10a
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• pp.297.2-297.2
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• 2002

Previous report showed that histamine release by HCI was mediated via reactive oxygen species (ROS) generation in RBL 2H3 cells. To investigate action of protein kinase on histamine release and ROS generation. we observed effects of protein kinase inhibitors on histamine release and ROS generation in RBL 2H3 cells stimulated by HCI HCI dose-dependently increased both histamine release and ROS generation. HCI-induced histamine release was significantly inhibited by bisindolmaleimide (10 ${\mu}$M). DHC (10 ${\mu}$M). , and wortmannin (10 ${\mu}$M), but not by PD098059 (10 ${\mu}$M). ON the other hand. HCI-induced ROS generation was significantly inhibited by DHC (10 ${\mu}$M). but not by bisindolmaleimide(10 ${\mu}$M). wortmannin (10 ${\mu}$M). and PD098059 (10 ${\mu}$M). However KN-62 did not inhibited both. These results showed that involvement of protein kinase in regulation of histamine release and ROS generation may be different and only tyrosine kinase may be associated with regulation of both histamine release and ROS generation in RBL 2H3 cells.

• Archives of Pharmacal Research
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• v.25 no.5
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• pp.675-680
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• 2002

In order to investigate the underlying mechanism of HCI in oesophagitis, the inflammatory response to HCI was observed in RBL-2H3 mast cells. Rat basophilic leukemia (RBL-2H3) cells were used to measure histamine release, arachidonic acid (AA) release, reactive oxygen species (ROS) and peroxynitrite generation induced by HCI. Exogenous HCl increased the level of histamine release and ROS generation in a dose dependent manner, whereas it decreased the spontaneous release of [$^3$H] M and the spontaneous production of peroxynitrite. Mepacrine (10 $\mu$M), oleyloxyethyl phosphorylcholine (10 $\mu$M) and bromoenol lactone (10 $\mu$M) did not affect both the level of histamine release and ROS generation induced by HCI. U73122 (1 $\mu$M), a specific phospholipase C (PLC) inhibitor did not have any influence on level of histamine release and ROS generation. Propranolol (200 $\mu$M), a phospholipase D (PLD) inhibitor, and neomycin (1 mM), a nonspecific PLC and PLD inhibitor, significantly inhibited both histamine release and ROS generation. Diphenyleneiodonium (10 $\mu$M), a NADPH oxidase inhibitor, and tiron (5 mM), an intracellular ROS scavenger significantly inhibited the HCI-induced histamine release and ROS generation. These findings suggest that the inflammatory responses to HCI is related to histamine release and ROS generation, and that the ROS generation by HCI may be involved in histamine release via the PLD pathway in RBL-2H3 cells.

• Toxicological Research
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• v.23 no.3
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• pp.215-221
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• 2007

Although sanguinarine, a benzophenanthridine alkaloid, possesses anti-cancer properties against several cancer cell lines, the molecular mechanisms by which it inhibits cell growth and induces apoptosis have not been clearly understood. In order to further explore the critical events leading to apoptosis in sanguinarine-treated MCF-7 human breast carcinoma cells, the following effects of sanguinarine on components of the mitochondrial apoptotic pathway were examined: generation of reactive oxygen species (ROS), alteration of the mitochondrial membrane potential (MMP), and the expression changes of Bcl-2 family proteins. We show that sanguinarine-induced apoptosis is accompanied by the generation of intracellular ROS and disruption of MMP as well as an increase in pro-apoptotic Bax expression and a decrease of anti-apoptotic Bcl-2 and Bcl-xL expression. The quenching of ROS generation with N-acetyl-L-cysteine, the ROS scavenger, protected the sanguinarine-elicited ROS generation, mitochondrial dysfunction, modulation of Bcl-2 family proteins, and apoptosis. Based on these results, we propose that the cellular ROS generation plays a pivotal role in the initiation of sanguinarine-triggered apoptotic death.

• Archives of Pharmacal Research
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• v.26 no.10
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• pp.809-815
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• 2003

Since reactive oxygen species (ROS) and hydroxyl radicals ($^-OH$) play an important role in the pathogenesis of many human degenerative diseases, much attention has focused on the development of safe and effective antioxidants. Preliminary experiments have revealed that the methanol (MeOH) extract of the stem of Prunus davidiana exerts inhibitory/scavenging activities on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radicals, total ROS and peroxynitrites ($ONOO^-$). In the present study, the antioxidant activities of this MeOH extract and the organic solvent-soluble fractions, dichloromethane (CH$_2$Cl$_2$), ethyl acetate (EtOAc), and n-butanol (n-BuOH), and the water layer of P. davidiana stem were evaluated for the potential to inhibit $^-OH$ and total ROS generation in kidney homogenates using 2',7'-dichlorodihydrofluorescein diacetate (DCHF-DA), and for the potential to scavenge authentic $ONOO^-$. We also evaluated the inhibitory activity of seven flavonoids isolated from P. davidiana stem, kaempferol, kaempferol 7-Ο-$\beta$-D-glucoside, (+)-catechin, dihydrokaempferol, hesperetin 5-Ο-$\beta$-D-glucoside, naringenin and its 7-Ο-$\beta$-D-glucoside, on the total ROS, $^-OH$ and $ONOO^-$ systems. For the further elucidation of the structure-inhibitory activity relationship of flavonoids on total ROS and 'OH generation, we measured the antioxidant activity of sixteen flavonoids available, including three active flavonoids isolated from P. davidiana, on the total ROS and 'OH systems. We found that the inhibitory activity on total ROS generation increases in strength with more numerous hydroxyl groups on their structures. Also, the presence of an ortho-hydroxyl group, whether on the Aring or S-ring, and a 3-hydroxyl group on the C-ring increased the inhibitory activity on both total ROS and $^-OH$ generation.

• Archives of Pharmacal Research
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• v.27 no.2
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• pp.194-198
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• 2004

Reactive oxygen species (ROS) play an important role in the pathogenesis of many human degenerative diseases such as cancer, aging, arteriosclerosis, and rheumatism. Much attention has been focused on the development of safe and effective antioxidants. To discover sources of antioxidative activity in marine algae, extracts from 17 kinds of seaweed were screened for their inhibitory effect on total ROS generation in kidney homogenate using 2',7'-dichlorofluorescein diacetate (DCFH-DA). ROS inhibition was seen in three species: UIva pertusa, Symphyocladia latiuscula, and Ecklonia stolonifera. At a final concentration of 25 $\mu\textrm{g}$/mL, U. pertusa inhibited 85.65$\pm$20.28％ of total ROS generation, S. latiscula caused 50.63$\pm$0.09％ inhibitory, and the Ecklonia species was 44.30$\pm$7.33％ inhibition. E. stolonifera OKAMURA (Lam-inariaceae), which belongs to the brown algae, has been further investigated because it is commonly used as a foodstuff in Korea. Five compounds, phloroglucinol (1), eckstolonol (2), eckol (3), phlorofucofuroeckol A (4), and dieckol (5), isolated from the ethyl acetate soluble fraction of the methanolic extrclct of E. stolonifera inhibited total ROS generation.

• Toxicological Research
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• v.32 no.4
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• pp.345-351
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• 2016

Propolis is a resinous material collected by honeybees from several plant sources. This research aimed at showing its protective effect against UVA-induced apoptosis of human keratinocyte HaCaT cells. Using Hoechst staining, it was demonstrated that propolis (5 and $10{\mu}g/mL$) significantly inhibited the apoptosis of HaCaT cells induced by UVA-irradiation. Propolis also showed the protective effect against loss of mitochondrial membrane potential induced by UVA-irradiaiton in HaCaT cells. Propolis also inhibited the expression of activated caspase-3 induced by UVA-irradiation. To investigate the role of ROS in UVA-induced apoptosis and protection by propolis, the generation of ROS was determined in cells. The results showed that the generation of ROS was markedly reduced in cells pretreated with propolis. Consequently, propolis protected human keratinocyte HaCaT cells against UVA-induced apoptosis, which might be related to the reduction of ROS generation by UVA-irradiation.

• Biomolecules & Therapeutics
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• v.27 no.1
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• pp.48-53
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• 2019

Reactive oxygen species (ROS) are widely generated in biological processes such as normal metabolism and response to xenobiotic exposure. While ROS can be beneficial or harmful to cells and tissues, generation of ROS by diverse anti-cancer drugs or phytochemicals plays an important role in the induction of apoptosis. We recently identified a derivative of naphthalene, MS-5, that induces apoptosis of an ovarian cell, CAOV-3. Interestingly, MS-5 induced apoptosis by down-regulating the ROS. Cell viability was evaluated by water-soluble tetrazolium salt (WST-1) assay. Apoptosis was evaluated by flow cytometry analysis. Intracellular ROS ($H_2O_2$), mitochondrial superoxide, mitochondrial membrane potential (MMP) and effect on cycle were determined by flow cytometry. Protein expression was assessed by western blotting. The level of ATP was measured using ATP Colorimetric/Fluorometric Assay kit. MS-5 inhibited growth of ovarian cancer cell lines, CAOV-3, in a concentration- and time-dependent manner. MS-5 also induced G1 cell cycle arrest in CAOV-3 cells, while MS-5 decreased intracellular ROS generation. In addition, cells treated with MS-5 showed the decrease in MMP and ATP production. In this study, we found that treatment with MS-5 in CAOV-3 cells induced apoptosis but decreased ROS level. We suspect that MS-5 might interfere with the minimum requirements of ROS for survival. These perturbations appear to be concentration-dependent, suggesting that MS-5 may induce apoptosis by interfering with ROS generation. We propose that MS-5 may be a potent therapeutic agent for inducing apoptosis in ovarian cancer cell through regulation of ROS.

• BMB Reports
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• v.41 no.8
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• pp.555-559
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• 2008

Reactive oxygen species (ROS) are generated in mammalian cells via both enzymatic and non-enzymatic mechanisms. Although certain ROS production pathways are required for the performance of specific physiological functions, excessive ROS generation is harmful, and has been implicated in the pathogenesis of a number of diseases. Among the ROS-producing enzymes, NADPH oxidase is widely distributed among mammalian cells, and is a crucial source of ROS for physiological and pathological processes. Reactive oxygen species are also generated by arachidonic acid (AA) metabolites, which are released from membrane phospholipids via the activity of cytosolic phospholipase $A_2$ ($cPLA_2$). In this study, we describe recent studies concerning the generation of ROS by AA metabolites. In particular, we have focused on the manner in which AA metabolism via lipoxygenase (LOX) and LOX metabolites contributes to ROS generation. By elucidating the signaling mechanisms that link LOX and LOX metabolites to ROS, we hope to shed light on the variety of physiological and pathological mechanisms associated with LOX metabolism.

• Journal of Physiology & Pathology in Korean Medicine
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• v.32 no.3
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• pp.157-164
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• 2018

This study was designed to investigate the mechanism of the synergistic anticancer effect of Astragalus membranaceus (AM) and Adenophora triphylla var. japonica (AT) in H1299 human lung carcinoma cells. A combined treatment of ethanol extract of AM (EAM) and AT (EAT) explosively increased the reactive oxygen species (ROS) generation in H1299 cells compared to the single treatment of each of them. Co-treatment of N-acetyl-L-cysteine (NAC) with EAM and EAT markedly enhanced the cell viability and suppressed apoptosis in H1299 cells, suggesting that ROS generation contributed to the anticancer effect of EAM and EAT. Interestingly, the combined treatment of EAM and EAT down-regulated p-AKT in H1299 cells, which was abrogated by NAC treatment. These results clearly indicated that ROS generation mediated the inactivation of AKT. Co-treatment of LY294002 with EAM and EAT significantly reduced the cell viability at a concentration which EAM and EAT didn't show any cytotoxicity. In addition, the recovery of cell viability by co-treatment of NAC with EAM and EAT was quite reversed by LY294002 treatment, which confirmed that the inactivation of AKT played a pivotal role in ROS-mediated apoptosis. Taken together, our results demonstrated that the synergistic anticancer effect of EAM and EAT was mediated by ROS generation and inactivation of AKT. We provide a valuable preclinical data for the development of more effective combination of AM and AT to treat lung cancer.

• Biomolecules & Therapeutics
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• v.28 no.1
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• pp.104-109
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• 2020

Probenecid is a representative drug used in the treatment of gout. A recent study showed that probenecid effectively inhibits oxidative stress in neural cells. In the present study, we investigated whether probenecid can affect osteoclast formation through the inhibition of reactive oxygen species (ROS) formation in RAW264.7 cells. Lipopolysaccharide (LPS)-induced ROS levels were dose-dependently reduced by probenecid. Fluorescence microscopy analysis clearly showed that probenecid inhibits the generation of ROS. Western blot analysis indicated that probenecid affects two downstream signaling molecules of ROS, cyclooxygenase 2 (COX-2) and c-Jun N-terminal kinase (JNK). These results indicate that probenecid inhibits ROS generation and exerts antiosteoclastogenic activity by inhibiting the COX-2 and JNK pathways. These results suggest that probenecid could potentially be used as a therapeutic agent to prevent bone resorption.