• 대한의생명과학회지
• /
• 제15권1호
• /
• pp.1-8
• /
• 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.

• BMB Reports
• /
• 제31권2호
• /
• pp.161-169
• /
• 1998

TThe reactive oxygen species oxidatively modify the biological macromolecules, including proteins, lipids, and nucleic acids. Iron- and heme-mediated Fenton-like reactions produce different pro-oxidants. However, these reactive products have not been clearly characterized. We examined the nature of the oxidizing species from the different iron sources by measuring oxidative protein modification and spectroscopic study. Hemoglobin (Hb) and methemoglobin (metHb) were oxidatively modified in $O{\array-\\\dot{2}}$ and $H_{2}O_{2}$ generating systems. Globin and bovine serum albumin (BSA) were also modified by iron, iron-EDTA, hematin, and Hb in an $O{\array-\\\dot{2}}$ generating system. In a $H_{2}O_{2}$ generating system, the iron- and iron-EDTA-mediated protein modifications were markedly reduced while the Hb-and hematin-mediated modifications were slightly increased. In the $O{\array-\\\dot{2}}$ generating system, the iron- and iron-EDTA-mediated protein modifications were strongly inhibited by superoxide dismutase (SOD) or catalase, but heme- and Hb-mediated protein modifications were inhibited only by catalase and slightly increased by SOD. Mannitol, 5,5-dimethyl-l-pyrroline-N-oxide (DMPO), deoxyribose, and thiourea inhibited the iron-EDTA-mediated protein modification. Mannitol and DMPO, however, did not exhibit significant inhibition in the hematin-mediated modification. Desferrioxamine (DFO) inhibited protein modification mediated by iron, but cyanide and azide did not, while the hematin-mediated protein modification was inhibited by cyanide and azide, but not significantly by DFO. The protein-modified products by iron and heme were different. ESR and UV-visible spectroscopy detected the DMPO spin adduct of the hydroxyl radical and ferryl ion generated from iron-EDTA and metHb, respectively. These results led us to conclude that the main oxidizing species are hydroxyl radical in the iron-EDTA type and the ferry I ion in the hematin type, the latter being more effective for protein modification.

• 한국미생물·생명공학회지
• /
• 제35권2호
• /
• pp.142-149
• /
• 2007

본 연구에서는 Bacillus subtilis를 첨가하여 발효시킨 감귤 가공부산물의 열수 추출액과 80% 메탄올 추출액을 가지고 항균활성과 항산화활성을 측정하였는데, 그 결과(Table 3)를 살펴보면 우선 열수추출법으로 추출한 시료에서는 추출온도를 $40^{\circ}C$하여 추출한 실험구(Bacillus subtilis 첨가구)와 비교 실험구(Bacillus subtilis 미 첨가구) 20 mg/ml 농도에서 항균활성이 높게 나타났다. 그리고 80% 메탄올을 사용하여 추출한 시료에 결과(Table 4)를 보면 열수추출법에 의해 추출한 실험 결과보다 전반적으로 높은 항균활성을 나타내는 것을 볼 수가 있다. 특히 $25^{\circ}C$에서 추출한 실험구에서 항균실험에 이용된 12종의 미생물 모두에서 높은 항균 활성을 나타내고 있다. DPPH method에 의한 radical 소거활성을 보면 열수추출법(Fig. 2)에서는 Bacillus subtilis 이용하여 발효시킨 시료를 $40^{\circ}C$에서 추출하였을 경우 10 mg/ml 농도에서 합성 항산화 제인 BHT보다 높고 BHA와 유사한 항산화 활성을 나타내었으며, 20 mg/ml 농도에서는 BHA보다 높은 활성을 나타내었다. 반면 80% methanol(Fig. 3)을 이용하여 Bacillus subtilis를 첨가하여 발효시킨 시료를 $25^{\circ}C$에서 추출 할 경우 5 mg/ml 농도에서는 BHT와 유사한 활성을 나타내며, 10 mg/ml에서는 BHA보다 높은 radical 소거활성을 나타내었으며, 20 mg/ml에서는 천연 항산화제인 ${\alpha}-tocopherol$보다 훨씬 높은 radical 소거활성을 나타내는 것을 알 수가 있다. 2-deoxyribose oxidation method에 의한 hydroxyl radical 소거활성을 보면 열수추출법으로 추출한 시료(Fig. 5)에서는 모든 시료에서 천연 항산화제와 합성 항산화제보다 높은 hydroxyl radical 소거활성을 보이는 시료는 나타나지 않았으나 Bacillus subtilis를 이용하여 발효시킨 시료를 $40^{\circ}C$에서 추출하여 20 mg/ml 농도로 실험하였을 때 합성 항산화제인 BHT와 유사한 활성을 나타내었고, Bacillus subtilis로 발효시키지 않은 시료 보다는 hydroxyl radical 소거활성을 나타내었다. 반면 80% methanol을 이용하여 추출한 시료(Fig. 6)에서는 Bacillus subtilis를 첨가하여 발효시킨 시료를 $25^{\circ}C$에서 추출 할 경우 5 mg/ml 농도에서 BHT 보다 높은 hydroxyl radical 소거활성을 나타내었으며, 10 mg/ml의 농도에서는 BHA 보다 높고 천연항산화제인 ${\alpha}-tocopherol$과 유사한 hydroxyl radical 소거활성을 나타내었다. 특히 20 mg/ml에서는 천연 항산화제인 ${\alpha}-tocopherol$ 보다 훨씬 높은 hydroxyl radical 소거활성을 나타내는 것을 볼 수가 있었다.

• 한국식품저장유통학회:학술대회논문집
• /
• 한국식품저장유통학회 2003년도 춘계총회 및 제22차 학술발표회
• /
• pp.22-39
• /
• 2003

Biological activity of phenolic compounds in seeds and leaves of safflower (Carthamu tinctorius L.) were evaluated using several in vitro and in vivo assays. Six phenolic constituents were isolated from the seeds and identified as N-feruloylserotonia, N- (p-coumaroyl)serotonin, matairesinol, 8′-hydroxyarctigenin, acacetin 7-O-$\beta$-D-glucoside (tilianine) and acacetin. Six phenolic compounds exhibited considerable antioxidative activity, and especially two serotonins showed potent DPPH radical scavenging activity and antiperoxidative activity against rat liver microsomal lipid peroxidation induced by the hydroxyl radical generated via a Fenton-type reaction. Additionally, six phenolic compounds possessed comparable cytotoxicity against three cancer cells, Hela cell, MCF-7 and HepG2 cell, and particularly acacetin and its glycosides had the most potent cytotoxicity. Moreover, we found that feeding safflower seeds attenuated bone loss, and lowered levels of plasma and liver lipids in ovariectomized rats. Serotonins, lignans and flavones stimulated proliferation of the osteoblast-like cells in a dose-dependent manner (10$^{-15}$ ~10$^{-6}$ M), as potently as E$_2$ (17$\beta$-estradiol). Particularly, serotonins were mainly responsible for bone-protecting and lipid lowering effects in ovariectomized rats. Meanwhile, eight flavonoids, including a novel quercetin-7-O-(6"-O-acetyl)-$\beta$-D-glucopyranoside and seven kown flavonoids, luteolin quercetin, luteolin 7-O-$\beta$-D-glucopyranoside, luteolin-7-O-(6"-O-acetyl)-$\beta$-D-gluco-pyranoside, quercetin 7-O- -glucopyranoside, acacetin 7-O-$\beta$-D-glucuronide and apigenin-6-C-$\beta$-D-glucopyranosyl-8-C-$\beta$-D-glucopyranoside were first isolated and identified from safflower leaf. Among these flavonoids, luteolin-acetyl-glucoside and $\beta$quercetin- acetyl-glucoside showed potent antioxidative activities against 2-deoxyribose degradation and lipid peroxidation in rat liver microsomes. Luteolin, quercetin and their corresponding glycosides also exhibited strong antioxidative activity, while acacetin glucuronide and apigenin-6, 8-di-C-glucoside were relatively less active. Finally, changes in phenolic compositions were also determined by HPLC in the safflower seed and leaf during growth stages and roasting process to produce standardized supplement powerds. These results suggest that phenolic compounds in the roasted safflower seed and leaf may be useful as potential sources of therapeutic agents against several pathological disorders such as carcinogenesis, atherosclerosis and osteoporosis.

• 한국식품과학회지
• /
• 제33권5호
• /
• pp.626-632
• /
• 2001

식물체(팽이버섯, 마늘, 녹차, allspice, 하수오, 오미자, 행인, 솔잎)가 free radical 반응 및 지방산화 억제에 미치는 영향과 nitrosamine 생성의 직접적인 영향인자인 아질산염에 대한 천연물의 분해효과를 검토한 결과 각 추출물의 pH는 열수추출물보다 ethanol추출물이 높은 pH를 나타내었으며, 그중에서 오미자 열수추출물이 3.0으로 가장 낮았다. 지방산화의 촉진인자인 $Fe^{2+}$ 이온과 활성산소 중 지방산화를 일으키는데 주요한 역할을 하는 hydroxyl radical에 대한 각 추출물들의 영향은 추출물 모두 $Fe^{2+}$ 이온 binding 능력은 탁월하였으며, deoxyribose상에서 OH 포집능 측정에서도 팽이버섯, 솔잎ethanol추출물이 다른 추출물에 비하여 낮은 TBARS값을 나타내었다. Iron의 함량은 열수추출물에서는 2.0 mg/100 g 미만이었으나, 오미자 추출물의 total iron 함량이 6.8 mg/100 g으로 가장 높게 나타났다. 용매별 iron함량 측정에서는 ethanol 추출물의 iron함량이 전반적으로 열수추출물보다 낮은 iron함량을 나타내었다. Ascorbic acid 함량은 녹차추출물이 열수 및 ethanol 추출에서 각각 14.3 mg/100 g, 16.7 mg/100 g을 나타내어 가장 높은 함량을 나타내었다. 전자공여능은 팽이버섯, 마늘 추출물을 제외하고 50% 이상의 전자공여능을 나타내었으며, 열수추출보다는 ethanol 추출물의 전자공여능이 우수하였다. SOD 유사활성은 전반적으로 8%이상의 활성능을 보였으나, 솔잎 ethanol추출물은 활성능이 미미하였으며. 녹차 열수와 ethanol추출물이 각각 85.3%, 63.5%로 가장 높은 활성능을 나타내었다. 아질산염 소거작용은 열수추출물이 전반적으로 ethanol추출물에 비하여 높은 소거능을 나타내었다. 녹차추출물의 열수와 ethanol 추출물은 아질산염 소거능이 매우 우수하였다.