• Advances in Traditional Medicine
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• v.3 no.3
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• pp.141-146
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• 2003

The methanol extracts of the aerial parts, leaves and stem of Hypericum hookerianum were tested for in vitro cytotoxicity on selected normal and cancer cell lines and anti tumor activity using DLA cells. Cell viability and morphological changes were assessed. Among the three extracts tested, the stem extract of Hypericum hookerianum showed potent cytotoxicity against HEp-2 and RD cell lines. The $CTC_{50}$(concentration required to reduce viability by 50%) of this extract was found to be $2.02\;{\mu}g/ml$ for RD cell line, $10.25\;{\mu}g/ml$ for HEp-2 cell line and $100.06\;{\mu}g/ml$ for Vero cell line. In the clonogenic assay, no colony formation was observed up to a concentration of $100\;{\mu}g/ml$. In the short term cytotoxicity studies using DLA cells, 50% viability was observed in the concentration range of $50-100\;{\mu}g/ml$ for aerial parts, $100-200\;{\mu}g/ml$ for stem and more than $200\;{\mu}g/ml$ for leaf extracts of Hypericum hookerianum. In the long-term activity using HEp-2 cell line, no colony formation was observed over a concentration of 200 mg/ml for the stem extract. Hypericum hookerianum stem extract was fractionated into petroleum ether, chloroform, ethyl acetate and methanol soluble fractions. The petroleum ether and chloroform soluble fractions showed higher cytotoxic activity against HEp-2 cell line when compared to the other two fractions. The methanol stem extract of Hypericum hookerianum has the potential for further investigation in animal models to determine its anti-tumor activity and to identify its active principles.

• The Korean Journal of Pharmacology
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• v.28 no.2
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• pp.213-222
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• 1992

We investigated effects of several chemical carcinogens, i.e., $benzo({\alpha})pyrene$ (BP),7,12-dimethylbenz(a)anthracene (DMBA), nitrosomethyl urea (NMU), and nicotine on the replication, cytolyticity, DNA synthesis, and protein synthesis of type 1 herpes simplex virus (HSV-1) in viral infected Vero cell monolayers. We observed that the BP and DMBA did not show such activity. All chemical carcinogens did not inhibit the synthesis of viral DNA, but the expression of gamma viral proteins that are expressed from the newly synthesized progeny viral DNA was somewhat notably inhibited by BP and DMBA. However, the synthesis of alpha and beta viral proteins was not altered by the chemical carcinogens. These data indicate that the gamma viral proteins expressed from the newly synthesized DNA in the presence of chemical carcinogens in the culture medium may be defective. This is further supported by the fact that the virus fail to replicate in the presence of these chemical carcinogens, in spite of viral DNA and proteins are somewhat normally synthesized.

• Korean Journal of Veterinary Research
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• v.33 no.2
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• pp.249-254
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• 1993

The etiological survey on porcine epidemic diarrhea virus(PEDV) by immunofluorescence antibody test(IFA) showed the positive rusult from the intestines of piglet died from acute diarrhea. The viral agent of PED was also isolated from intestine, which showed positive reaction by immunofluorescence test. After passage in Vero cell, the viral agent was further cloned by plaque purification and designated as KPEDV-9. The immunoblotting analysis using hyperimmune sera and porcine sera revealed the presence of several polypetide bands with molecular weight(M.W.) of 88K, 74K, 70K, 58~54, 54~46K, 44~40K and 33~32K, respectively.

• Korean Journal of Veterinary Research
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• v.41 no.2
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• pp.189-195
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• 2001

Single base substitution and deletion mutation have been introducted into the verotoxin 2 (VT2)A subunit gene from O157:H7 isolates to reduce cytotoxicity of VT2 and the cytotoxicity between wild type toxin and mutant toxoid were compared. A M13-derived recombinant plasmid pEP19RF containing a 940bp EcoRI-PstI fragment of VT2A gene was constructed for oligonucleotide-directed mutagenesis. The duoble mutant pDOEX was constructed by point and deletion mutation of two different highly conserved regions of VT2A encoding active site cleft of enzymatic domain. The key residue, Glu 167(GAA) and the pentamer(WGRIS) consisting of the enzymatic domain were replaced by ASP(GAC) and completely deleted in nucleotide sequence analysis of mutant, respectively. In the comparision of vero cell cytotoxicity between wide type toxin and toxoid from mutant, the wild type toxin expressed cytotoxicity in dilution of $10^{-6}$, but the toxid from mutant did not show cytotoxicity to vero cells.

• BMB Reports
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• v.52 no.6
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• pp.397-402
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• 2019

Middle East respiratory syndrome coronavirus (MERS-CoV) uses the spike (S) glycoprotein to recognize and enter target cells. In this study, we selected two epitope peptide sequences within the receptor binding domain (RBD) of the MERS-CoV S protein. We used a complex consisting of the epitope peptide of the MERS-CoV S protein and CpG-DNA encapsulated in liposome complex to immunize mice, and produced the monoclonal antibodies 506-2G10G5 and 492-1G10E4E2. The western blotting data showed that both monoclonal antibodies detected the S protein and immunoprecipitated the native form of the S protein. Indirect immunofluorescence and confocal analysis suggested strong reactivity of the antibodies towards the S protein of MERS-CoV virus infected Vero cells. Furthermore, the 506-2G10G5 monoclonal antibody significantly reduced plaque formation in MERS-CoV infected Vero cells compared to normal mouse IgG and 492-1G10E4E2. Thus, we successfully produced a monoclonal antibody directed against the RBD domain of the S protein which could be used in the development of diagnostics and therapeutic applications in the future.

• Biomolecules & Therapeutics
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• v.30 no.5
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• pp.427-434
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• 2022

The drug repurposing strategy has been applied to the development of emergency COVID-19 therapeutic medicines. Current drug repurposing approaches have been directed against RNA polymerases and viral proteases. Recently, we found that the inhibition of the interaction between the SARS-CoV-2 structural nucleocapsid (N) and spike (S) proteins decreased viral replication. In this study, drug repurposing candidates were screened by in silico molecular docking simulation with the SARS-CoV-2 structural N protein. In the ChEMBL database, 1994 FDA-approved drugs were selected for the in silico virtual screening against the N terminal domain (NTD) of the SARS-CoV-2 N protein. The tyrosine 109 residue in the NTD of the N protein was used as the center of the ligand binding grid for the docking simulation. In plaque forming assays performed with SARS-CoV-2 infected Vero E6 cells, atovaquone, abiraterone acetate, and digoxin exhibited a tendency to reduce the size of the viral plagues without affecting the plaque numbers. Abiraterone acetate significantly decreased the accumulation of viral particles in the cell culture supernatants in a concentration-dependent manner. In addition, abiraterone acetate significantly decreased the production of N protein and S protein in the SARS-CoV-2-infected Vero E6 cells. In conclusion, abiraterone acetate has therapeutic potential to inhibit the viral replication of SARS-CoV-2.

• Journal of Plant Biotechnology
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• v.49 no.4
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• pp.347-355
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• 2022

Jeju lava seawater's abundant minerals are known to exert antioxidant effects that remove the free radicals responsible for aging. Therefore, lava seawater reportedly possesses high commercial value as a functional food material. This study compared and analyzed the antioxidant activities of extracts from crops produced in Jeju (carrots, blueberries, and mandarins) using distilled water and lava seawater as solvents. Lava seawater extracts exhibited higher total polyphenol and flavonoid contents of blueberries and mandarins than distilled water extracts. Furthermore, the antioxidant enzymatic and 2, 2-diphenyl-1-picrylhydrazyl radical-scavenging activities of these crops were higher in lava seawater extracts than in distilled water extracts. In particular, using Vero cells, the ROS-scavenging efficacies of blueberries and mandarins were found to be higher in lava seawater extracts. Meanwhile, the antioxidant activities of carrots were higher in lava seawater extracts, despite no difference in total polyphenol and flavonoid contents. These results suggest that lava seawater exhibits favorable potential as a solvent in the functional food industry, and lava seawater-based Jeju crop extracts are potentially useful as functional food ingredients.

• Clinical and Experimental Pediatrics
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• v.46 no.2
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• pp.143-153
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• 2003

Purpose : Infection with Shiga-like toxin (SLT)-producing Escherichia coli, an emerging human pathogen found particularly in young children under 5 years of age, causes a spectrum of illnesses with high morbidity and mortality, ranging from diarrhea to hemorrhagic colitis and hemolytic uremic syndrome. Host mediators play an important role in the pathogenesis of SLT-I toxicity. The experiments described here were designed to investigate the effect of SLT-I on TNF-${\alpha}$ production and to understand the effect of TNF-${\alpha}$ on GB3 expression. We also further examine the relationship between the Gb3 level and the differential susceptibility of cells to the cytotoxic action of SLT-I. Methods : The effect of purified SLT-1 from E. coli O157 : H7 (ATCC 43890) on tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) production in Raw264.7 cells was investigated. Many mediators regulate endothelial cell membrane expression of the glycolipid globotriaosyleramide (Gb3), which serves as the toxin receptor, suggesting that the host response to the toxin or other bacterial products may contribute to pathogenesis by regulating target cell sensitivity to the toxins. Therefore, the relationships between Gb3 expression and cytotoxicity against SLT-I on three types of cells were evaluated. Results : Detectable levels of TNF-${\alpha}$ were produced as early as six hours after induction and continued to increase during 48 hours by SLT-I. It was also found that Vero cells and dendritic cells (DC2.4 cells) expressed high levels of Gb3, 83% and 68%, respectively, and that Raw264.7 cells had a low level of Gb3 (29%) and appeared refractory to cytotoxicity against SLT-I. Vero cells and DC2.4 cells expressing high levels of Gb3 were highly susceptible to SLT-I. Furthermore, macrophages showed a resistance to SLT-I cytotoxicity, despite the fact that Gb3 expression was enhanced. Conclusion : These results strongly suggest that the expression of Gb3 is necessary but not sufficient to confer sensitivity of macrophages to SLT-I and further underpin the important role of SLT-I and its Gb3 receptors in the pathogenesis of E. coli O157 infection.

• Journal of Food Hygiene and Safety
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• v.15 no.3
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• pp.241-247
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• 2000

The incidence of verotoxin-producing Escherichia coli(VTEC) was surveyed in domestic foods including hamburger, raw meats and vegetables from 1997 to 1999. The molecular biological characteristics of the isolates were analyzed. Three VTEC strain were isolated from 1,700 samples. Serotypes of those isolates were 0157 : H7, 026 H4, and 056 : Hl2, respectively. Serotype O26 : H4 produced VT I and VT II, and 055 Hl2 isolate produced VT I, however the 60 MDa plasmid DNA and eae gene were not found from both strains. One 0157 : H7 isolate produced VT II and harbour 60 MDa plasmid DNA, however eae gene was not found in the strain. Although they produced VT, it seemed that the virulence of two strains were relatively weak because of the lack of the eae gene. In addition, the serotype O157 : H7 isolate resistant to ampicillin and streptomycin, while isolates of serotype O26 : H4 and O55 : Hl2 were multi-resistant to antibiotics including ampicillin, carbenicillin , cephalothin, trimethoprim/sulfamethoxazole and tetracycline. Supernatants of cultures of all three isolates were showed cytotoxic effect to vero and HeLa cell

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.1
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• pp.449-454
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• 2014

Background: Extracts of Caesalpinia mimosoides Lamk has been reported to possess anticancer effects, but the active ingredients and the anti-cancer mechanisms are still unknown. Materials and Methods: The effects of a C mimosoides Lamk extract on cell proliferation and apoptosis induction in human cervical carcinoma cell lines, namely HeLa, SiHa, and C33A, as well as in normal Vero cells, were investigated. Results: Treatment with 5 active fractions (F17-F21) of C mimosoides Lamk methanol extracts inhibited cell viability in a dose- and time-dependent manner. Neutral red assays indicated that treatment with F21 significantly decreased the viability of all cervical cancer cell lines compared to F21-treated normal cells. In addition, HPLC analysis revealed that F21 contained multiple phenolic compounds, namely gallic acid, caffeine, vanillic acid, ferulic acid and resveratrol. F21 had the lowest IC50 and, therefore, a much higher cytotoxicity than F20, F17, F19, and F18 by 20-, 25-, 46- and 47- fold, respectively. Analysis of activation of the apoptosis pathway using a caspase 3/7 activity assay revealed that F21 treatment resulted in a considerable increase in caspase activation in all cancer cell lines tested. At the same concentration of F21, HeLa cells had the highest caspase activity (6.5-fold) compared to the control. Conclusion: C mimosoides Lamk may be of value as an alternative therapeutic agent, especially in combination with other compounds offering possible of synergy of action. Moreover, HPV- and non-HPV-related cervical cancer cells may differ in their responses to treatment regimens.