The electron transport chain (ETC) delivers electrons from many substrates to reduce molecular oxygen to water. ETC accomplishes the stepwise transfer of electrons through series of protein complexes conferring oxidation‐reduction reactions with concomitant transport of p roton across membrane, g enerating a proton g radient which leads ATP s ynthesis b y F0F1ATPase. Bacterial ETC initiates with oxidation of NADH by NADH dehydrogenase complex (complex I). Therefore, damage of complex I leads to insufficient function of ETC and accumulation of NADH inside the cell. Contribution of ETC activity and its consequent changes of NADH levels to bacterial damage response against reactive oxygen and nitrogen species (ROS/RNS) has been poorly understood. In this study, by constructing ndh mutant Salmonella lacking complex I NADH dehydrogenase 2, we evaluated the effect of ETC deficiency to bacterial resistance against ROS and RNS. The growth of ndh mutant Salmonella is impaired in the culture media containing hydrogen peroxide, but rather accelerates in the media containing nitric oxide donors. Data suggest that redox potential of NADH accumulated inside the cell by ETC blockage may affect inversely to bacterial resistance against reactive oxygen species and reactive nitrogen species.

Intracellular pathogens must maintain redox homeostasis against the antimicrobial actions of reactive oxygen and nitrogen species produced by host cells. This study proves that glutathione is required to promote survival of an enteric pathogen Salmonella under the conditions producing reactive oxygen or nitrogen species. Glutathione is the non-protein thiol compound distributed in a variety of organisms and possesses strong electron-donating capability to reduce intracellular redox environment. To examine the role of glutathione on Salmonella redox homeostasis under oxidative and nitrosative stress conditions, gshB gene encoding glutathione synthetase was mutated by the one-step PCR inactivation method. The growth of gshB mutant Salmonella producing virtually no glutathione was greatly impaired in the culture media containing either hydrogen peroxide or nitric oxide donors. The results suggest that physiological levels of glutathione can provide a fundamental capability to maintain redox homeostasis for Salmonella in surviving oxidizing conditions of host cells.

양강추출물(Alpinia officinarum, 70% ethanol extract)과 함유 주성분인 galangin은 프리라디칼소거작용과 지질과산화억제활성을 나타내었으며, H_2O_2 또는 KO_2유도 세포독성에 대해서도 억제적으로 작용하여 세포보호효과를 나타내었다. DNA single strand breakage와 같은 산화적 스트레스에 대해서도 보호작용을 하고 있다. 또한, 마우스 소핵시험에 의하여 adriamycin과 같은 superoxide유발물질에 의한 염색체 수준에서의 손상에 대해서도 억제효과를 나타내었다. 양강추출물은 galangin을 유효성분으로하여 산소프리라디칼들에 의한 산화적 손상에 억제적으로 작용하는 기전으로 산화적 스트레스에 대한 항노화, 암예방제로서의 응용가능성이 높은 추출물로서 향후 기능성 식품으로서의 응용가능성이 높을 것으로 판단되었다.

Background : We have previously reported that Oligonol, a low-molecular polyphenol derived from lychee fruit, has protective effect on the liver and kidney of diabetic animal model. In this study, we examined whether Oligonol has any beneficial effects on pancreas of diabetic rats. Methods and Results : Oligonol was orally administered at a dose of 10 and 20 mg/kg body weight for 10 days to STZ-induced diabetic rats, and the effects were compared with those of vehicle-treated diabetic control and non-diabetic control rats. The administration of Oligonol reduced hyperglycemia in diabetic rats through an improvement of serum and pancreatic insulin levels. The increased reactive oxygen species levels in pancreas of diabetic control rats was attenuated by the Oligonol administration through inhibiting the expression of NADPH oxidase-related proteins. The enhanced expression of pro-apoptotic proteins in pancreas of diabetic control rats was significantly reduced by Oligonol administration through down-regulation of phosphor-c-Jun N-terminal kinases protein in pancreas. Furthermore, the expressions of cell proliferation-related protein were also augmented in Oligonol treated-diabetic rats. However, Oligonol treatment led to improved histological changes in the pancreas. Conclusion : These pancreatoprotective effects of Oligonol were achieved through attenuation of oxidative stress and its sensitive protein expression associated with apoptosis and cell proliferation in diabetic rats.

본 연구는 4종의 별의별간(SS) 음료의 간보호 소재로서 의 이용 가능성을 조사하고자 항산화능 평가, t-BHP 와 CCl4로 산화적 손상 및 급성 간독성 유도한in vitro, in vivo 모델을 활용하여 간보호능을 평가하였다. 실험결과, 별의별간 01~04는 50 μM vitamin C 와 유사한 항산화 효과를 나타내었다. HepG2 세포에 t-BHP로 산화 스트레스를 유도한 뒤 나타나는 세포독성에 대해 별의별간 01 및 04에서 농도 의존적인 세포 보호효과를 보였으며, ROS 생성 억제에서 별의별간 01, 03, 04에서 농도의존적인 억제를 나타내었다. 미나리가 혼합된 별의별간 04에 대한 급성 간손상in vivo 모델을 활용하여 간보호능 검증 결과, 별의별간 04는 CCl4로 증가된 혈중 ALT, AST의 유의적 감소, 간 조직중 증가된 MDA 함량 감소 및 감소된 GSH의 유의적 증가를 나타내었다. 또한, 혈청 및 간 조직에서 증가 된 중성지방과 콜레스테롤을 유의적으로 감소시켰다. 이러 한 결과를 종합하며, 별의별간 04는in vitro 및in vivo 모델 에서 산화적 손상에 대해 간보호 효과를 나타내었다

활성산소종(reactive oxygen species, ROS)인 glucose oxidase(GO)의 산화적 손상이 배양 C6glioma 세포에 미치는 영향 및 이에 대한 연꽃(Nelumbo nucifera GAERTN, NNG) 추출물의 항산화 효과를 세포생존율(cell viability)을 비롯한 DPPH-radical scavenging activity, lipid peroxidation에 의하여 분석하였다. 본 연구에서 H2O2는 배양 C6 glioma세포에 처리한 농도에 비례하여 유의한 세포생존율의 감소를 나타냈다. 한편, GO의 산화적 손상에 대한 NNG추출물의 방어효과를 조사하기 위하여 세포생존율을 조사한 결과 NNG 추출물은 GO의 산화적 손상으로 감소된 세포생존율을 유의하게 증가시켰다. 또한, NNG 추출물은 DPPH-radical scavenging activity의 분석에서 유의한 자유라디칼 소거능을 보였으며, 동시에 지질과산화에 대한 억제능을 보였다. 위의 결과로 부터 GO는 배양 C6 glioma세포에 고독성인 것으로 나타났으며 NNG추출물은 GO와 같은 ROS의 산화적 손상을 방어하는데 효과적인 것으로 나타났다.

본 연구는 t-butyl hydroperoxide(t-BHP)의 산화적 손상에 대한 원지(Polygalae Radix, PR)추출물의 항산화 효과를 알아보기 위하여 배양 C6 glioma 세포를 재료로 세포생존율을 비롯하여 superoxide dismutase(SOD) 유사 활성을 비롯하여 lactate dehydrogenase(LDH) 활성을 조사하였다. 본 실험에서 t-BHP는 농도 의존적으로 배양 C6 glioma 세포의 생존율을 유의하게 감소시켰다. 한편, t-BHP의 세포독성에 대한 원지 추출물의 항산화 효과의 정량분석에 있어서 원지 추출물은 t-BHP의 산화적 손상으로 감소된 세포생존율의 유의한 증가를 비롯하여 LDH 활성감소 및 SOD 유사 활성을 보임으로서 항산화 효과를 나타냈다.

This study assessed the characteristics of emission and cell toxicology of Methylethylketone(MEK) in ambient air of industrial area. MEK is produced by the oxidation of sec-butyl alcohol and used as the solvent for making ink, printing, coating of film, bonding material and drug extraction. The MEK concentrations in the ambient-air of industrial area in Gimhae City was detected in the range of 25.4～1,580 ㎍/㎥ with an average 297.4 ㎍/㎥. The concentration of MEK showed a descending tendency from April to August followed by its increased tendency since then. The effects of MEK on the human lung cancer A549 cells was examined by the generation of Reactive Oxygen Species(ROS) and cytotoxicity. The range of MEK concentration detected in the area induced ROS generation affecting the oxidation state with a little effects on the viability of the cells.