• Radiation Oncology Journal
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• v.13 no.2
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• pp.113-120
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• 1995

Purpose : To investigate the effect of alkaloid fraction from Korean ginseng on radiation-induced DNA double strand breaks (dsb) formation and repair in murine lymphocytes Materials and Methods : We used the neutral filter elution technique to assay $^{60}Co\;{\gamma}$ ray-induced DNA double strand breaks formation and repair in C57BL/6 mouse spleen lymphocytes for evaluating the dose-response relationship in the presence of alkaloid fraction as a radioprotective agent. The lymphocytes were stimulated with Phytohemagglutinin (PHA, 2 u g/ml) to label $^3[H]-thymidine.$ Isotope-labelled lymphocytes in suspension were exposed to 100 Gy at $0^{\cdot}C$ in the alkaloid fraction-treated group and elution procedure was performed at PH 9.6. The extents of formation of radiation-induced DNA double strand breaks and repair were compared respectively via strand scission factor (SSF) and relative strand scission factor (RSSF). Results: Alkaloid fraction reduced the formation of double strand breaks with dose modification factor of 2 15, compared to control group Rejoining of DNA dsb appeared to take place via two components. The first fast component was completed within 20.4 minutes, but the second slow component was not completed until 220.2 minutes after irradiation. About $30\%$ of dsb formed by irradiation was ultimately unrejoined despite the administration of alkaloid fraction. The administration of alkaloid fraction had a great effect on the second slow component of repair; the half-time of fast component repair was not changed, but that of slow component was 621.8 minutes. Conclusion: Neutral filter elution assay Proved to be a very effective method to quantitate the extents of DNA dsb formation and its repair. By using this technique, we were able to evaluate the efficiency of alkaloid fraction from Korean ginseng as a valuable radioprotector. Alkaloid fraction can be used prophylactically to prevent or ameliorate the severe radiation damages in workers and neighbors around the atomic power plants. For more refined study, however, more advanced purification of alkaloid fraction wil be needed in the near future.

• Archives of Pharmacal Research
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• v.26 no.2
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• pp.124-127
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• 2003

Four known prenylated flavonoids, artonins E (1) and O (2), artobiloxanthone (3), and cycloartobiloxanthone (4), were isolated from the stem bark of Artocarpus kemando by bioassayguided fractionation using the DNA strand-scission and the KB cytotoxicity assays as monitors. Compounds 1 and 3 exhibited strong DNA strand-scission activity, and all four compounds were found to be cytotoxic.

• Applied Biological Chemistry
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• v.48 no.3
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• pp.222-227
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• 2005

To evaluate the antimutagenic activity of the specialty rices, a giant embryonic rice and a pigmented rice, we measured the inhibitory effect on the chemically induced mutagenesis in E. coli and V79 cultured cell system, as well as on DNA strand scission induced by oxidative damages in vitro. When the inhibitory activity to mitomycin C-induced mutagenesis using SOS chromotest in E. coli cell was measured, the activities decreased in the following order: germinated pigmented rice (40.4%) > germinated giant embryonic rice (37.1%) > pigmented rice (35.5%) > germinated brown rice (15.7%) > giant embryonic rice (14.0%) > brown rice (0.8%). The activities for inhibiting mitomycin C-induced DNA strand scission decreased in the order of pigmented rice > giant embryonic rice > germinated pigmented rice > germinated brown rice > brown rice > germinated giant embryonic rice. We also determined antimutagenic activities of the specialty rices using the suppressing effect on 6-TG resistant colony formation by 4-NQO in V79 cells as a mutagenicity index. The order of antimutagenicity was germinated giant embryonic rice (53.2%) > pigmented rice (40.0%) > brown rice (21.2%) > germinated brown rice (14.4%) > giant embryonic rice (0.23%); in contrast, germinated pigmented rice showed promoting effect on 4-NQO-induced mutagenesis.

• Korean Journal of Veterinary Research
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• v.31 no.3
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• pp.329-335
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• 1991

The filter elution technique was used to assay $^{60}Co$ $\gamma$ ray-induced DNA strand breaks(SB) in EL4 mouse leukemia cell and mouse spleen lymphocyte. The lymphocytes were stimulated with lipopolysaccharide (LPS, $20{\mu}g/ml$) to label $[^3H]$ thymidine. EL4 cells and lymphocytes in suspension were exposed at $0^{\circ}C$ to 0Gy, 1Gy, 5Gy, 10Gy or l5Gy for DNA single strand breaks(SSB) assay and 0Gy, 25Gy, 50Gy, 75Gy or 100Gy for DNA double strand breaks(DSB) assay of $^{60}Co$ radiation and elution procedure was performed at pH12.1 and 9.6. The number of DNA strand breaks increased with increasing doses of r rays. The strand scission factor(SSF) was estimated in each experiment (eluted volume 21ml). The slope of SSB EL4 cells was $0.01301{\pm}0.00096Gy^{-1}$ (n=5), the slope of SSB for lymphocytes was $0.01097{\pm}0.00091Gy^{-1}$ (n=5) and the slope of DSB for lymphocytes was $0.001707{\pm}0.0000573Gy^{-1}$ (n=5). Thus EL4 cells were more sensitive to induction of DNA SSB by ionizing radiation than lymphocytes (p<0.005). The ratio of slope of dose-response relationship (SSF versus dose) of lymphocytes DNA SSB as compared with the slope of DNA DSB was 6.4.

• Biomedical Science Letters
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• v.15 no.1
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• pp.1-8
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• 2009

Human genomic DNA is continuously attacked by oxygen radicals originated from cellular metabolic processes and numerous environmental carcinogens. 2-deoxyribonolactone (dL) is a major type of oxidized abasic (AP) lesion implicated in DNA strand scission, mutagenesis, and formation of covalent DNA-protein crosslink (DPC) with DNA polymerase (Pol) ${\beta}$. We show here that human DNA polymerase (Pol)${\iota}$ and mitochondrial $Pol{\gamma}$ give rise to stable DNA-protein crosslink (DPC) formation that is specifically mediated by dL lesion. $Pol{\gamma}$ mediates DPC formation at the incised dL residue by its 5'-deoxyribose-5-phosphate (dRP) lyase activity, while $Pol{\gamma}$ cross links with dL thorough its intrinsic dRP lyase and AP lyase activities. Reactivity in forming dL-mediated DPC was significantly higher with $Pol{\gamma}$ than with $Pol{\iota}$. DPC formation by $Pol{\gamma}$, however, can be reduced by an accessory factor of $Pol{\gamma}$ holoenzyme that may attenuate deleterious effects of crosslink adducts on mitochondrial DNA. Comparative kinetic analysis of DPC formation showed that the rate of DPC formation with either $Pol{\iota}$ or $Pol{\gamma}$ was lower than that with $Pol{\beta}$. These results revealed that the activity of catalytic lyase in DNA polymerases determine the efficiency of DPC formation with dL damages. Irreversible crosslink formation of such DNA polymerases by dL lesions may result in a prolonged strand scission and a suicide of DNA repair proteins, both of which could pose a threat to the genetic and structural integrity of DNA.

• Applied Biological Chemistry
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• v.41 no.1
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• pp.78-83
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• 1998

Anticarcinogenicity of 12 kinds of colored rice cultivars was investigated in vitro with Ilpumbyeo as a control. Pigment and hexane fractions were prepared from the rice brans through extraction with 80% ethanol containing 0.5% TFA or n-hexane to use subsequent evaluation of their anticarcinogenic effect by determining inhibitory activity against DNA strand scission and tumor promotion, as well as antimutagenic activity using SOS chromotest system. Antimutagenic activity of the pigment fractions was revealed to decrease in order of LK1B4-12-1-1 > Sanghaehanghyulla > HP833-1-3-1-1 > Chokoto14 > Jagwangdo > Jajin > Kilmheugmi > Tiwan-Tsi-C > Heugjinmi > Linsia-Shoea-Dau > Suweon425 > Suweon415. The activity of the hexane fractions decreased in order of LK1B4-12-1-1 > Sanghaehyanghyulla>Ilpunibyeo > HP833-1-3-1-1 > Chokoto14 > Jagwangdo > Jajin > Linsia-Shoea-Dau >Tiwan-Tsi-C > Heugjinmi > Suweon425, Kilimheugmi > Suweon415. Results showed that inhibitory activity against DNA strand scission in the pigment fractions decreased in order of HP833-1-3-1-1 > Tiwan-Tsi-C > Jajin > Chokoto14 > Suweon425 > Heugjinmi > LK1B4-12-1-1 > Suweon415 > Jagwangdo > Kilimheugmi > Linsia-Shoea-Dau > Sanghaehyanghyulla. On the other hand, the activity of the hexane fractions decreased in order of LK1B4-12-1-1 > Suweon 415 > Kilimheugmi > Chokoto14 > Heugjinmi > Jajin > Suweon425 > Tiwan-Tsi-C > Sanghaehyanghyulla a Linsia-Shoea-Dau > Jagwangdo > HP833-1-3-1-1 > Ilpumbyeo. Experiment using the short-term assay for promotor substance showed that inhibitory activity contained in the pigment fractions against rumor promotor TPA decreased in order of Linsia-Shoea-Dau > Kilimheugmi > HP833-1-3-1-1, Suweon425 > Heugjinmi > Jajin > Chokoto14 > Sanghaehyanghylla > Suweon 415 > LK1B4-12-1-1 > Tiwan-Tsi-C > Jagwangdo.

• Animal cells and systems
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• v.9 no.2
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• pp.79-85
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• 2005

Oxidized abasic residues arise as a major class of DNA damage by a variety of agents involving free radical attack and oxidation of deoxyribose sugar components. 2-deoxyribonolactone (dL) is a C1'-oxidized abasic lesion implicated in DNA strand scission, mutagenesis, and covalent DNA-protein cross-link (DPC). We show here that mammalian cell-free extract give rise to stable DPC formation that is specifically mediated by dL residue. When a duplex DNA containing dL at the site-specific position was incubated with cell-free extracts of Po ${\beta}-proficient$ and -deficient mouse embryonic fibroblast cells, the formation of major dL-mediated DPC was dependent on the presence of DNA polymerase (Pol) ${\beta}$. Formation of dL-specific DPC was also observed with histones and FEN1 nuclease, although the reactivity in forming dL-mediated DPC was significantly higher with Pol ${\beta}$ than with histones or FEN1. DNA repair assay with a defined DPC revealed that the dL lesion once cross-linked with Pol ${\beta}$ was resistant to nucleotide excision repair activity of cell-free extract. Analysis of nucleotide excision repair utilizing a model DNA substrate containing a (6-4) photoproduct suggested that excision process for DPC was inhibited because of DNA single-strand incision at 5' of the lesion. Consequently DPC mediated by dL lesion may not be readily repaired by DNA excision repair pathway but instead function as unusual DNA damage causing a prolonged DNA strand break and trapping of the major base excision repair enzyme.

• Korean Journal of Pharmacognosy
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• v.44 no.3
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• pp.224-229
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• 2013

Bromotopsentin (BSM) is a bisindole alkaloid compound, which is recognized as a metabolite of the marine sponge Spongosorites sp. In this study, the antioxidant activity of BSM was investigated. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay, the trolox equivalent antioxidant capacity (TEAC) assay, the superoxide radical scavenging (NBT) assay, the lipid peroxidation and hydroxyl radical-induced DNA damage assays were carried out to evaluate the antioxidant activity of BSM. It was found that BSM had stronger scavenging activity on the stable free radical DPPH and superoxide radical than L-ascorbic acid with an $IC_{50}$ value of 62 and 64 ${\mu}M$, respectively. The TEAC value which indicated the total antioxidant capacity of BSM was about 0.8, which was also stronger than L-ascorbic acid. About 1.3 ${\mu}M$ of BSM induced 50% inhibition of lipid peroxidation. 60 nM of BSM exhibited a significant protective activity against DNA strand scission by hydroxyl radical on pBR322 DNA. Taken together, we suggest that BSM possesses strong antioxidant activity, and could be a valuable new addition to the list of anti-aging chemotherapeutic agents.

• Applied Biological Chemistry
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• v.46 no.1
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• pp.32-38
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• 2003

Seventy percent ethanolic extracts from commercially available 13 legumes were made to investigated their antioxidative activities by determining the reducing power, inhibitory effect on lipid peroxidation, scavenging activity against both superoxide radical and hydroxyl radical, together with inhibitory activity toward mitomycin C-induced oxidative damage of DNA. High level of reducing powers were detected in Yepat, Sokpiri, Yuweol-bean and Jeokdu. Inhibitory effects on lipid peroxidation were found ubiquitously in all extracts examined when employing the linoleic acid autoxidation system, whereas, only 3 legumes, Yepat, Namul-bean and Jeenuni-bean, were revealed marked inhibition in rabbit erythrocyte-ghost membrane lipid peroxidation system. Yepat, Namul-bean, Jeokdu and Jeenuni-bean showed great scavenging activities on superoxide radical, on the other hand, high level of hydroxyl radical scavenging activities were demonstrated in Sokpiri, Chungtae, Yepat and Jebi-bean. Ubiquitous inhibitory effects on mitomycin C-induced oxidative damage on DNA were found in all extracts tested, Among them, however, Yepat, Jeenuni-bean, Namul-bean, Nokdu and Jeokdu showed the higher level of inhibition. Taken together, we could assign Yepat, Jeokdu, Jeenuni-bean and Sokpiri, for the legume species highly functional on overall antioxidative activity.

• Natural Product Sciences
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• v.10 no.6
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• pp.277-283
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• 2004

Psammaplin A (PSA), a naturally occurring biophenolic compound has been demonstrated to deliver significant cytotoxicity to many cancer cell lines. In this article, we investigated the effect of PSA on cell cycle progression of lung cancer cells (A549). It was found that PSA could slightly perturb the cell cycle progression of A549 cells and lead to the cell cycle arrest at G2/M phase, indicating PSA might disturb the mitosis process of A549 cells. In addition, inspired by the two phenolic groups in the structure of PSA, the antioxidant activity of it has been evaluated. Although PSA was weak in scavenging the stable free radical 1,1-diphenyl-2-picrylhyrazyl (DPPH), it showed stronger ABTS radical scavenging activity than ascorbic acid in TEAC assay. Furthermore, it was found that PSA could effectively prevent DNA strand scission induced by oxidative stress. These results suggest that PSA have both cell cycle regulation and antioxidant activities. Herein, we suggest that PSA would be a very interesting and promising candidate to be developed as a multi-function drug.