여정실의 항산화 활성

서영완,김호준 한국해양과학기술원 2017 Ocean and Polar Research Vol.39 No.2

The objective of this study is to evaluate the antioxidant activity of the fruits of Ligustrum japonicum. The crude extract was successively fractionated into n-hexane, 85% aqueous methanol (85% aq.MeOH), n-butanol (n-BuOH), and water fractions by means of solvent polarity. The crude extract and its solvent fractions were evaluated for their antioxidant effect by four different assay systems: scavenging power on peroxynitrite and intralcellular ROS produced in HT-1080 cells; DNA oxidation inhibition; ferric reducing antioxidant power (FRAP). The n-BuOH fraction exhibiting potent antioxidant activity was further purified by C18 silica gel column chromatography and RP-HPLC to give tyrosol (1) and salidroside (2). The structure of isolated compounds was determined by extensive 2 D NMR experiments such as 1H COSY, NOESY, HSQC and HMBC as well as by comparison with the published spectral data.

주주총회 소집통지제도의 형평성 등에 대한 고찰

서영완 한국증권법학회 2023 증권법연구 Vol.24 No.1

The notification for the convocation of shareholders’ general meeting is to provide shareholders with information and reference materials about on the agenda of general meeting so that they can vote well. In the case of listed companies, as stocks are distributed among many shareholders, public notice or electronic disclosure can be substituted for individual notification. However, the current Korean commercial law stipulates dual methods of providing information for the shareholders’ general meeting depending on the shareholding ratio, which may violate the principle of equality of shareholders rights. On the other hand, if there is a high possibility of achieving a special policy purpose, such as increasing the attendance rate at the shareholders' meeting, there might be a need to maintain such an exceptional policy. However, it is unlikely that the special objectives of such a policy will be concretely realized. Therefore, it is appropriate to minimize the notification costs by allowing the electronic disclosure system for all shareholders of listed companies, regardless of ownership ratio.

Antioxidant Properties of Erigeron annuus Extract and Its Three Phenolic Constituents

서영완,이희정 한국생물공학회 2006 Biotechnology and Bioprocess Engineering Vol.11 No.1

The antioxidant activity of the extract of Erigeron annuus was assessed by means of two different in vitro tests: bleaching of the stable 1,1-diphenyl-2-picrylhydrazyl radical (DPPH test) and the scavenging of authentic peroxynitrite in company with peroxynitrite generation from 3-morpholinosydnonimine (SIN-1). In both tests, the 85% aq. MeOH and n-BuOH soluble fractions of the crude extract showed a significant scavenging effect on peroxynitrite and DPPH radical in comparison to L-ascorbic acid. And bioassay-guided fractionation of the n-BuOH soluble fraction led to the isolation of three compounds: Apigenin (1), quercetin-3-O-glucoside (2), and caffeic acid (3). The structures of the isolated compounds were elucidated on the basis of their spectroscopic data and their antioxidant activities were measured by determining their capacity to scavenge peroxynitrite and the DPPH radical.

In vitro Peroxynitrite Scavenging Activity of Arctic Seaweed Extracts

서영완,Hee-Jung Lee,You Ah Kim,Jung-Im Lee,Ji Hee Kim,Hosung Chung,Sung-Ho Kang 한국해양과학기술원 2007 Ocean and Polar Research Vol.29 No.2

In this study, antioxidant activities of acetone/dichloromethane and methanol extracts of Arctic seaweeds were investigated. The antioxidant properties of both extracts of arctic seaweed were evaluated using two different peroxynitrite tests, including scavenging power on authentic peroxynitrite and inhibitory activities on peroxynitrite generation from 3-morpholinosydnonimine (SIN-1) producing superoxide anion and nitric oxide simultaneously in vitro. At concentration of 10 mg/ml, the acetone/dichloromethane and methanol extracts of Odonthalia dentata exhibited 54.6 and 64.2% inhibition against peroxynitrite generation from SIN-1 while they exhibited 24.3 and 23.0% scavenging activities on authentic peroxynitrite, respectively. On the other hand, the acetone/dichloromethane extract of Polysiphonia stricta exhibited 61.8% inhibition only against the induced peroxynitrite from SIN-1. Furthermore, the crude extracts of Odonthalia dentata and Polysiphonia stricta were fractionated into n-hexane, 85% aq. MeOH, n-BuOH, and H2O fractions, successively, and only 85% aq. MeOH fraction exhibited the best inhibition.

Growth pattern analysis by stem analysis of Korean white pine (Pinus koraiensis) in the central northern region of Korea

서영완,Safa Balekoglu,최정기 한국산림과학회 2014 Forest Science And Technology Vol.10 No.4

The study was performed to find the growth pattern by stem analysis of Korean white pine (Pinus koraiensis) in the CentralNorthern Region of Korea. One standard tree from each of 16 sites was stemmed and analyzed for the study. For sampledtrees, the age range was 1677 years, diameter at breast height (DBH) was 15.844.4 cm, height was 9.324.0 m, andstem volume was 0.10021.8518m3. The stem volumes by our study had higher values over 40DBH compared to KoreaForest Research Institute measurements. The bark volume had no particular trend with DBH and height, while bark ratiotended to decrease with DBH and height. The DBH and height curves by age had a concave shape whereas volume curvehad a convex shape. The average periodic annual increment (PAI) of DBH was the highest at age 15 (1.0 cm/yr), and thehighest value of the mean annual increment (MAI) of DBH was 0.7 cm/yr at age 30. The highest values of PAI and MAI ofheight were 0.6 m/yr (age 15) and 0.5 m/year (age 25) respectively. The average PAI and MAI of volume continued toincrease even after age 75. Growth percentages of DBH, height and volume tended to decrease with age, particularlyrapidly at age 2030. Volume growth percentage was much higher than diameter and height.

Growth Analysis of Red Pine (Pinus densiflora) by Stem Analysis in the Eastern Region of Korea

서영완,이대성,최정기 강원대학교 산림과학연구소 2015 Journal of Forest Science Vol.31 No.1

The study was performed to analyze the growth of the red pine (Pinus densiflora) in the Eastern Region of Korea. Stem profile data from a total of 8 dominant trees of which each tree represents its site were collected and used for the analysis. The stem volumes were calculated using Smalian’s formula and much higher than the ones by Korea Forest Research Institute in larger than dbh 40 cm. The total bark volumes were more proportionally related to dbh and stem volume than to height and age. The bark thickness and volume decreased as relative height increases but increased as relative dbh increased. The average PAI of dbh and height reached the highest at 0.8 cm/yr (age 15) and at 0.45 m/yr (age 30) respectively, while the average PAI of volume steadily tended to increase up to age 80. The growth percentages of dbh, height and volume tended to decrease with age and volume growth percentage was higher than dbh and height.

소규모 전환권 행사에 대한 효율적인 자기주식 결제방법

서영완 한국증권법학회 2022 증권법연구 Vol.23 No.3

사채권자가 전환권을 행사하면 회사는 매번 신주를 발행해야 하므로 비용이 발생하며, 상법은 부담완화를 위해 일정 기간 이후에 발행할 수 있도록 허용하므로 사채권자 환금성이 제약을 받는다. 한편, 해외에서는 권리행사가 수반되는 다양한 형태의 증권에 대하여 자기주식이나 현금으로도 결제할 수 있도록 발행하고 있다. 만일, 국내에서도 이러한 결제방법을 활용할 수 있다면 회사의 발행비용도 절감하면서 동시에 투자자의 환금성을 높일 수 있다. 자기사채 취득방법과 같은 대안적 방법을 활용할 수 있는지에 대하여 검토한 결과, 긍정적인 해석이 가능하더라도 법적 분쟁이 발생할 가능성에 대한 우려로 인하여 활용도가 부진할 수 있다. 따라서 전환권 행사에 대하여 발행회사가 자기주식으로 결제할 수 있도록 입법적인 개선방안을 마련할 필요가 있는데, 자기주식 결제조건부 자기사채 취득방법을 제도화하면 빈번한 절차적 부담을 대폭 해소할 수 있다. 특히, 현금유동성이 많지 않은 회사는 증권대차거래를 활용하여 자기주식을 차입하면 전환권 행사에 대하여 신속하고 효율적으로 결제하는 등 자본시장의 운영효율성이 크게 개선될 것으로 보인다.

2,5-Diarylisoxazolidin-3-ones의 합성에 관한 연구

서영완,문광율,이윤영,김경태,Youngwan Seo,Kwang Ryul Mun,Youn Young Lee,Kyongtae Kim 대한화학회 1992 대한화학회지 Vol.36 No.3

염화 삼메틸규소를 첨가하지 않고 에테르나 사염화탄소 중의 3-Aryl-3-bromopropanoyl chloride를 상온에서 2당량의 히드록실아민과 반응시켜 2,5-diarylisoxazolidin-3-ones 을 좋은 수율로 얻을 수 있었다. 그러나 $0^{\circ}C$에서 3-bromohydrocinnamoyl chloride 는 2당량의 벤질히드록실아민과 반응하여 N-benzyl-3-bromo-3-phenylpropanohydroxamic acid (72%) 와 N-benzyl-C-phenylnitrone (12%)을 생성하며 같은 조건하에서 3당량의 벤질히드록실아민을 사용하면 3-phenylisoxazolidin-5-one (41%) 과 2-benzyl-S-phenyl-isoxzolidin-3-one (38%)이 생성된다. 3-Aryl-3-bromopropanoyl chloride in either ether or carbon tetrachloride reacted with 2 equiv. of hydroxylamine in the absence of trimethylsilyl chloride at ambient temperature to give directly 2,5-diarylisoxazolidin-3-ones in good yields. However, when 3-benzylhydroxylamine at $0^{\circ}C$, N-benzyl-3-bromo-3-phenylpropanohydroxamic acid (72%) and N-benzyl-C-phenylnitrone (12%) were obtained. On the contrary, 3-phenylisoxazolidin-5-one (41%) and 2-benzyl-S-phenyl-isoxzolidin-3-one (38%) were obtained when 3 equiv. of benzylhydroxylamine was used under the same conditions.

In Effects of Several Salt Marsh Plants on Mouse Spleen and Thymus Cell Proliferation Using MTT Assay

서영완,윤현주,이범종,이희정,You Ah Kim 한국해양과학기술원 2005 Ocean science journal Vol.40 No.4

In the present study, we have tested the effects of 21 salt marsh plants on cell proliferation of mouse immune cells (spleen and thymus) using MTT assay in culture. The methanolic extracts of six salt marsh plants (Rosa rugosa, Ixeris tamagawaensis, Artemisia capillaris, Tetragonia tetragonoides, Erigeron annus, and Glehnia littoralis) showedvery powerful suppressive effects of mouse immune cell death and significant activities of cell proliferation in vitro. Especially, the methanolic extract of Rosa rugosa was found to have fifteen times compared to the control treatment, demonstrating that Rosa rugosa may have a potent stimulation effect on immune cell proliferation. These results suggest that several salt marsh plants including Rosa rugosa could be useful for further study as an immunomodulating agent.

DBH growth for three years after thinning on even-aged Pinus koraiensis and Larix kaempferi plantations in South Korea

서영완,Somsanouk Pathammavongsa,Vireak Chhorn,이대성,최정기,차두송 한국산림과학회 2019 Forest Science And Technology Vol.15 No.1

This study was conducted to determine the effects of different thinning intensities on the DBH growth of Pinus koraiensis and Larix kaempferi trees. Permanent monitoring plots were installed in 26 P. koraiensis plantations and 36 L. kaempferi plantations in 2012 and 2014, respectively. To evaluate the effect of thinning intensity, each plot consisted of three square or rectangular plots; control or non-thinned, light thinning, in which 20% of the total basal area was removed, and heavy thinning, in which 40% of the total basal area was removed. The mean DBH increments for 3 years were computed and compared across thinning intensities. Other factors, such as slope, altitude, or stand density, were compared across thinning treatments to understand why DBH increment did not follow thinning intensity. Overall mean DBH increment for 3 years after thinning was affected by different thinning intensities: heavy thinning>light thinning>control. ANOVA showed that there was a significant difference in DBH increment among thinning intensities in both species. Also, Duncan’s multiple range test showed that all thinning treatments were significantly different from each other. Other factors that affect DBH besides thinning intensity were identified, such as residual basal area, slope gradient, and aspect.