Suppression of iNOS Expression by Phlorotannins in Chronic Exposure of Skin to UVB Radiation

Hyejeong Hwang,Tong Chen,Gary D. Stoner,Kyun-Bok Lee,Yung-Choon Yoo,Hyeon-Cheol Shin 한국실험동물학회 2005 Laboratory Animal Research Vol.21 No.4

Nitric oxide (NO), endogenously produced by NO synthase (NOS), is an important regulatory molecule for immune response and cytotoxicity. Up-regulation of inducible NOS (iNOS) and increased NO production occur in many pathological conditions associated with inflammation. Multiple exposures to solar ultraviolet (UV) radiation cause critical damages that may lead to development of several cutaneous disorders including skin cancer. In this study, we assessed the inhibitory effects of polyphenols extracted from brown algae, phlorotannins, on UVB-induced iNOS gene expression using SKH-1 hairless mouse model. The mice were treated orally with phlorotannins (0.1% and 0.5% with diet, w/w) and topically (3 ㎎ and 6 ㎎/0.2 ㎖ of solvent per mouse) and irradiated with UVB (160 mJ/㎠) three times per week for 26 weeks. Dietary feeding of 0.1% and 0.5% phlorotannins remarkably reduced iNOS gene expression by 73% and 88%, respectively (p < 0.05). Topical treatment of 3 ㎎ and 6 ㎎ phlorotannins also showed a significant decrease in iNOS induction by 79% and 94%, respectively (p < 0.05). These observations demonstrate that dietary feeding and topical application of phlorotannins afford strong protection against UVB-induced iNOS suppression and inflammatory damage in the skin. Furthermore, the results of this study suggest phlorotannins may be useful as a preventive agent against inflammatory responses associated with photocarcinogenesis and other adverse effects of UVB exposure.

Edge와 GHT를 이용한 증거물 검색 시스템

황혜정(HyeJeong Hwang),채옥삼(OkSam Chae) 대한전자공학회 2003 대한전자공학회 학술대회 Vol.2003 No.11

Beneficial Effects of the Mixed Adjuvant of CpG plus Monophosphoryl Lipid A in Immunization with a Recombinant Protein Vaccine for Hepatitis A

Hwang, Inkyu,Choi, Daewoon,See, Hyejeong,Kim, Wonyong,Chung, In Sik,Shon, Dong-Hwa 한국응용생명화학회 2013 Applied Biological Chemistry (Appl Biol Chem) Vol.56 No.1

In an effort to develop a new vaccine for hepatitis A, which is mainly transmitted via contaminated foods and water, recombinant virus protein 1 (VP1) of hepatitis A virus was used as an antigen. Several adjuvants in a single or a mixed form, i.e., alum, CpG oligodeoxynucleotide, monophosphoryl lipid A (MPL), alum plus MPL, and CpG plus MPL, were also tested for their immunological properties. When their effects on the production of VP1-specific IgG relative to that of total IgG and the levels of and balance between Th1- and Th2-type cytokine productions were compared, CpG plus MPL was found to have highly beneficial effects, providing a new insight in selection of adjuvant for development of a new vaccine.

Change of 6BA depending on germination period of soybean sprouts

Hyejeong Yun,Dong-gyu Lee,Hyunji Lim,Sat-Baeul Kim,Seonghun Jeong,Jae-hyung Hong,Eun-hee Chang,Mi-jeong Gwon,Hyangran Hwang,Eun-mo Jeong 한국분석과학회 2022 학술대회논문집 Vol.2022 No.5

Degradation of surface film on LiCoO₂ electrode by hydrogen fluoride attack at moderately elevated temperature

Jeong, Hyejeong,Kim, Jongjung,Soon, Jiyong,Chae, Seulki,Hwang, Seunghae,Ryu, Ji Heon,Oh, Seung M. Elsevier 2018 ELECTROCHIMICA ACTA Vol.277 No.-

<P><B>Abstract</B></P> <P>The failure mechanism of LiCoO<SUB>2</SUB> electrode at moderately elevated temperature (70 °C) is examined. To this end, a Li/LiCoO<SUB>2</SUB> cell is cycled 10 times within 3.0–4.3 V (<I>vs</I>. Li/Li<SUP>+</SUP>) to deposit a surface film on the LiCoO<SUB>2</SUB> electrode, followed by storage at 70 °C for 10 h. The charge/discharge cycling data obtained at 25 °C after the storage reveal that the cell is damaged by the storage. The Coulombic efficiency decreases because the charging capacity is larger than that observed before the storage. The increased charging capacity is due to electrolyte oxidation. The postmortem analyses of the stored electrodes show that the surface film on the LiCoO<SUB>2</SUB> electrode becomes thinner after storage and with a notable compositional change compared to before storage. The increased charging capacity after the storage can be attributed to the extra electrolyte oxidation on the damaged (thinned) LiCoO<SUB>2</SUB> electrode surface. The loss of passivating ability due to surface film damage is responsible for the extra electrolyte oxidation and poorer Coulombic efficiency. Meanwhile, the chemical composition of the damaged film is very similar to that of the surface film stored with added hydrogen fluoride (HF, 400 ppm) in the electrolyte. It is thus suggested that the surface film is damaged by attack of HF generated from LiPF<SUB>6</SUB> during the high-temperature storage. Evidently, a decrease of LiPF<SUB>6</SUB> concentration in the electrolyte mitigates the film damage and the associated electrode degradation.</P>

VisiSens 산소 평면광 센서 시스템을 이용한 식물 잎 표면의 산소분포 가시화

황배근(BaeGeun Hwang),김혜정(HyeJeong Kim),이상준(SangJoon Lee) 한국가시화정보학회 2016 한국가시화정보학회지 Vol.14 No.1

Oxygen is a key factor in aerobic reactions and most biological activities. Visualization of oxygen distribution of a chemical process or biological system has been a very challenging object despite of its significance and potential impact. To monitor and visualize the spatial distribution of oxygen concentration, various techniques such as electro-chemical probe, polarographic electrode, LIF(laser-induced fluorescence) and so on have been introduced. Oxygen planar optode which utilizes the oxygen quenching of fluorescence light is one of the currently available methods for time-resolved visualization of oxygen distribution on a planar surface. In this study, we utilized VisiSens oxygen planar optode system to visualize the spatial distribution of oxygen concentration on leaves of Korean azalea. As a result, temporal variation of oxygen concentration distribution caused by respiratory activity of the leaf could be quantitatively monitored.

Predictors for Non-Use of Contraceptives among Rural Ethiopian Women

Hyeonkyeong Lee,Taewha Lee,Hyejeong Shin,Wonju Hwang,Hyunmi Ahn 한국간호과학회 2011 한국간호과학회 학술대회 Vol.2011 No.10

외래식물 핑크뮬리(Muhlenbergia capillaris)의 메탄올 추출물이 식물 생장에 미치는 영향

홍민지(Minji Hong),보셀라(Sela Bo),장혜정(Hyejeong Jang),조남규(Nam-kyu Cho),황기환(Ki Hwan Hwang),손하라라잔 칸다사미(Kandhasamy Sowndhararajan),홍선희(Sun hee Hong),이용호(Yong Ho Lee),김성문(Songmun Kim) 한국잡초학회 2021 Weed & Turfgrass Science Vol.10 No.3

전국의 많은 지방자치단체에서 외래식물인 핑크뮬리를 무분별하게 도입하여 관상용으로 식재하고 있다. 핑크뮬리는 자생식물과 경쟁하여 국내 생태계에 언제든지 영향을 미칠 수 있지만 이에 대한 연구는 전무한 형편이다. 본 연구에서 저자들은 외래식물인 핑크뮬리가 식물의 생장에 어떠한 영향을 미치는지 조사하였다. 개화기의 핑크뮬리 식물을 채취하여 메탄올 추출물을 얻고 in vitro에서 seed bioassay, 온실 조건에서 토양 처리 및 경엽 처리 실험을 수행하였다. 핑크뮬리 메탄올 추출물의 유채식물에 대한 뿌리 길이 및 생체중에 대한 GR50 값은 각각 4,147 및 4,997 μg mL<SUP>-1</SUP> 이었는데, 이와 같은 결과는 핑크뮬리가 타감작용을 나타낼 가능성이 존재한다는 것을 나타낸다. 10 종의 식물종자가 파종된 토양에 핑크뮬리 추출물(10 kg ha<SUP>-1</SUP>)을 살포한 결과 어떠한 식물생장 저하도 관찰되지 않았다. 그리고 핑크뮬리 추출물(10 kg ha<SUP>-1</SUP>)을 식물의 경엽에 살포한 경우에도, 피에서의 미약한 피해를 제외하고는, 대부분의 식물에서는 생장억제나 약해가 발견되지 않았다. 결론적으로 외래식물인 핑크뮬리는 in vitro에서는 알렐로파시 효과를 나타내었만 in vivo에서는 다른 식물의 생장에 영향을 주지는 않았다. Pink Muhly is planted and managed for ornamental purposes by many local governments in Korea across the country. However, it could affect the domestic ecosystem at any time and compete with native plants due to its exotic nature. The objective of this study was to understand whether pink muhly affects the growth of plants. We obtained the methanol extract from a fully grown pink muhly plant and executed an in vitro seed bioassay followed by soil treatment and foliage treatment experiments under greenhouse conditions. The growth retardation (GR) 50 values, at which plant growth is inhibited by 50%, of methanol extract against root length and weight were 4,147 and 4,997 μg mL<SUP>-1</SUP>, respectively. The results suggest that Pink Muhly may possess allelopathic potential. Application of the Pink Muhly extract (10 kg ha<SUP>-1</SUP>) on the soil in which ten plants were planted, did not show any adverse effect. Further, the application of the Pink Muhly extract (10 kg ha<SUP>-1</SUP>) to the foliage did not show any damage and inhibition of growth. Overall results show that although the exotic plant Pink Muhly showed an allelopathic effect, it might not inhibit the growth of other plants.

Communication—Electrochemical Conversion of CuV₂O₆ into Metallic Cu and LiVO₃ with Highly Reversible Lithium Storage

Lee, Jeong Beom,Chae, Seulki,Jeong, Hyejeong,Hwang, Hong Seo,Jung, Jiwon,Ryu, Ji Heon,Oh, Seung M. The Electrochemical Society 2017 Journal of the Electrochemical Society Vol.164 No.4

<P>Copper metavanadate (CuV2O6) is tested as a negative electrode for lithium-ion batteries. In the first lithiation, CuV2O6 takes 12 Li+ ions/electrons, during which both Cu2+ and V5+ ions are reduced into their elemental states. In the forthcoming de-lithiation period, only the metallic vanadium is oxidized to form LiVO3, while the metallic copper is idling. From the second cycle, the as-generated LiVO3 is lithiated by a conversion reaction, delivering a reversible capacity of ca. 1000 mA h g(-1). It shows an unusually good cycle retention and Coulombic efficiency owing to the beneficial roles offered by the idling metallic copper. (C) 2017 The Electrochemical Society. All rights reserved.</P>

어성초 메탄올 추출물로부터 항산화 효능을 가진 활성물질의 확인

김혜지(Hyeji Kim),황희성(Heesung Hwang),박수민(Sumin Park),강성욱(Sungwook Kang),김혜정(Hyejeong Kim),홍수경(Sugyeong Hong),김문무(Moon-Moo Kim),오영희(Yunghee Oh) 한국생명과학회 2017 생명과학회지 Vol.27 No.7

본 연구는 어성초의 메탄올 추출물을 이용하여 항산화 효능이 가장 좋은 fraction을 찾고, 항산화 효능을 나타내는 성분을 분석하였다. 메탄올 추출에 의한 유기 용매 별 분획에서 항산화 효과가 가장 좋은 ethyl acetate 분획물을 칼럼 크로마토그래피하여 12가지의 fraction 중 가장 높은 항산화 효과를 보인 Fr. 10을 이용하여 DPPH 라디칼의 소거활성, 환원력, 지질과산화, 세포독성, DNA 산화 및 DCFH-DA를 이용한 세포내 과산화수소 제거효과를 조사하였다. DPPH radical scavenging activity, reducing power, TBARS, cell viability, DNA oxidation and DCF fluorescence 12가지의 fraction들 중 항산화 효능이 가장 좋은 Fr. 10의 DPPH radical 소거 활성 결과로 64 μg/ml 농도에서 양성대조군에 근접하는 60%의 억제능을 보였다. Reducing power 결과로 32 μg/ml의 농도에서 140%로 양성대조군과 비슷한 결과 값을 보였다. TBARS 결과로 2 μg/ml에서 양성대조군과 같은 값의 활성산소 억제능이 나타난다. 또한 cell viability 결과로 32 μg/ml 이상의 농도에서 세포 독성에 의해 생존율이 감소하였고, DCF fluorescence 결과로 농도의존적으로 H2O2에 의한 산화적 손상을 억제하는 것으로 나타났다. DNA oxidation 실험결과 1 μg/ml 이상의 농도에서 DNA의 손상을 감소시킴을 확인할 수 있었다. IR 및 LC-MS를 이용하여 Fr. 10의 유효성분을 조사한 결과 rutin (분자량, 610)으로 확인 되었다. 결론적으로 어성초의 메탄올 추출물로부터 분리한 Fr. 10은 농도 의존적으로 항산화 효능이 우수하게 나타났고, 어성초는 화장품 및 기능성 식품의 소재로 활용될 수 있음을 시사한다. This study was carried out to evaluate the antioxidant effect of methanolic extract of Houttuynia cordata (HCME) and to identify a compound having antioxidant effect. The ethyl acetate fraction of HCME showed the highest antioxidant effect in organic solvent fractions. The fraction was then separated into 12 fractions by open column chromatography. Among these fractions, the fraction 10 (Fr. 10) with the highest antioxidant activity was isolated, and its antioxidant effect was evaluated by DPPH radical scavenging activity, reducing power, TBARS, cell viability, DNA oxidation and DCF fluorescence. The Fr. 10 at a 64 μg/ml showed 60% of inhibitory effect similar to that of vitamin C at 10 μg/ml, compared with blank group. The Fr. 10 at 64 μg/ml showed 264% of reducing power, compared with blank group. TBARS assay showed that the Fr. 10 at 64 μg/ml had 35.5% of inhibitory effect similar to that of vitamin E at 1,000 μg/ml, compared with blank group. The Fr. 10 above 32 μg/ml displayed cytotoxicity. However, it was observed that the Fr. 10, above 1 μg/ml reduced DNA damage. DCF fluorescence assay showed that the Fr. 10 inhibited oxidative stress by H₂O₂ in a dose dependent manner. The compound of Fr. 10 was identified to be rutin whose molecular weight is 610 by the IR and LC-MS analyses. Therefore, these results suggest that the rutin of Fr. 10 could use as a natural antioxidant for development of cosmetics and functional foods.