양지꽃(Potentilla fragarioides) 지상부의 항산화물질

최용화,김명조,이행순,윤봉식,호창서,곽상수,Choi, Yong-Hwa,Kim, Myong-Jo,Lee, Haeng-Soon,Yun, Bong-Sik,Hu, Changxu,Kwak, Sang-Soo 한국생약학회 1998 생약학회지 Vol.29 No.2

Six antioxidative compounds in the aerial parts of Potentilla fragarioides were isolated by a bioassay guided purification using a DPPH free radical. They were identified as (+)-catechin, isoquercitrin, quercitrin, $quercetin-3-O-{\beta}-D-glucopyranosyl-{\beta}-D-xylopyranoside$, caffeic acid, and 4-O-caffeoyl-L-threonic acid on the basis of $^{1}H$ and $^{13}C-NMR$ and MS data. The DPPH radical scavenging activity of five compounds $(RC_{50}:\;7.5{\sim}10.5\;{\mu}g)$ except for quercitrin $(16\;{\mu}g)$ was more effective than those of ${\alpha}-tocopherol$ $(12\;{\mu}g)$ and BHA $(14\;{\mu}g)$.

해당화(Rosa rugosa) 잎의 항산화물질

최용화,김명조,이행순,호창서,곽상수,Choi, Yong-Hwa,Kim, Myong-Jo,Lee, Heang-Soon,Hu, Chang-Xu,Kwak, Sang-Soo 한국생약학회 1997 생약학회지 Vol.28 No.4

To search for useful antioxidants from plant materials, we investigated the antioxidative activity in the methanol extracts of 30 Chinese medicinal plants using DPPH method. The highest activity $(RC_{50}:\;12\;{\mu}g)$ was showed in the methanol extract of Rosa rugosa, followed by Potentilla fruticosa $(14\;{\mu}g)$, P. fragarioides $(16\;{\mu}g)$. And Geum aleppicum $(18\;{\mu}g)$. From the leaves of R. rugosa, two antioxidative compounds were isolated by a bioassay guided purification and identified as isoquercitrin and ${\beta}-glucogallin$ on the basis of $^1H-,\;^{13}C-\;NMR$, and FAB-MS data. ${\beta}-Glucogallin$ is the first report in this plant. The DPPH radical scavenging activity of ${\beta}-glucogallin\;(RC_{50}:\;8.5\;{\mu}g)$ was more effective than those of ${\alpha}-tocopherol\;(12\;{\mu}g)$ and BHA $(14\;{\mu}g)$.

특별강연 요지 : 벼 초기 발생과정에 있어서 내생 Gibberellin 의 생합성기능과 역할의 해석

최용화 한국잡초학회 1995 한국잡초학회 별책(학술대회 초록집) Vol.15 No.2

제4주제 : 수원 순교 성지의 성역화 조성 과정과 순교 신심의 고취(논평)

최용화 수원교회사연구소 2005 교회사학 Vol.0 No.2

Brassinosteroids 의 생합성

최용화 한국응용생명화학회 1996 농업생명과학 Vol.3 No.1

Imidazole계 살균제 Prochloraz의 토양 중 잔류량과 반감기분석

최용화,한성수,김일광 한국분석과학회 2002 분석과학 Vol.15 No.1

residual analysis and half-life time of imidazole fungicide prochloraz in soils (silty clay) were investigated by gas chromatography equipped electron capture detector (GC-ECD). The soil samples were extracted acetone/hexane(1:1) solvent and analyzed after separated by LC-NH2 Sep-Pak solid column. Linear sensitivity of standard calibration curve was Y = 268.8600X + 0.0664, R2 = 0.9998 between 0.05∼1.00 ng. The detection limit was 0.02 ㎎/L and the average recoveries were 94.5∼97.3% from the standard additional experiments with 0.10 and 0.40 ㎎/L. The half-life time was 24.4 days in room laboratory and 7.6 days in the field test soil.

밤나무 잎으로부터 항산화 활성물질의 분리

최용화,김진호,김명조,한성수,임요섭 한국약용작물학회 2000 한국약용작물학회지 Vol.8 No.4

밤나무(Castanea crenat)의 지상부를 대상으로 DPPH free radical 소거법을 이용하여 2종의 항산화 활성물질을 분리하였다. 분리된 활성물질은 NMR과 mass 분석에 의하여 quercitrin, isoquercitrin으로 밝혀졌다. 두 화합물의 DPPH free radical 소거법에 의한 항산화 활성 (RC50 : 12μg)은 BHA (14 μg)와 α-tocopherol (12μg)과 비슷하였다. Two antioxidative compounds in leaves of Castanea crenata were isolated by a bioassay using a DPPH free radical. They were identified as quercitrin, isoquercitrin on the basis of 1H and 13C-NMR and MS data. The DPPH radical scavenging activity (RC50 : 12 μg) of two compounds was similar to that of α-tocopherol (12μg) and BHA (14μg).

굴피나무(Platycarya strobilacea) 지상부로부터 항진균성 활성물질 분리

최용화,채상기,김진호,강상재,백남인,한재택 한국응용생명화학회 2003 Journal of Applied Biological Chemistry (J. Appl. Vol.46 No.3

Methanol extract obtained from aerial parts of Platycarya strobilacea was successively fractionated with n-hexane, ethylacetate, n-butanol, and water. From ethylacetate fraction, an active compound was isolated through repeated silica gel column chromatography and was identified as 5-hydroxy-2-methoxy-1,4-naphthoquinone by MS and NMR analyses. The compound showed in vivo 76% antifungal activity at $100\;{\mu}g/ml$ against tomato late blight disease. 굴피나무 지상부의 메탄을 추출물을 n-hexane, ethylacetate, n-butanol, H₂O으로 순차적으로 용매분획하였다. Ethylacetate 분획으로부터 silica gel chromatography를 반복하여 활성물질을 분리 정제하였다. 화합물은 NMR과 MS의 기기분석 결과 5-hydroxy-2-methoxy-1,4-naphthoquinone로 구조결정 되었다. 이 화합물은 in vivo 실험결과 토마토역병에 대하여 $100\;{\mu}g/ml$에서 76%의 방제효과를 나타내었다.

주파수-파수 스펙트럼과 라돈변환을 이용한 희소 배열 기반 방위추정 기법 연구

최용화,김동현,김재수,Choi, Yong Hwa,Kim, Dong Hyeon,Kim, J.S. 한국음향학회 2019 韓國音響學會誌 Vol.38 No.2

배열의 설계주파수보다 높은 주파수의 표적신호가 수신되는 경우 공간 에일리어싱에 의해 빔형성에 모호성이 발생한다. 이를 극복하기 위해 Abadi가 차주파수 빔형성 기법을 제안하였다. 하지만 차주파수 빔형성 기법은 차주파수의 값에 따라 최소한의 대역폭이 필요한 제약조건이 있다. 본 논문에서는 주파수-파수 스펙트럼의 특성과 라돈변환을 이용하여 공간 에일리어싱이 발생하는 표적신호의 방위를 추정하는 기법을 제안한다. 제안된 기법은 대역을 가지는 신호의 주파수 대역 내에서 방위추정의 모호성은 발생하지 않고, 표적의 방위를 추정할 수 있다. 하지만 대역을 가지는 신호에만 적용이 가능한 제약조건이 있다. 광대역 신호에 대해 시뮬레이션을 수행하여 알고리즘을 구현하고, 이를 SAVEX15 (Shallow Water Acoustic Variability EXperiment 2015)의 딱총새우 소음신호를 이용하여 차주파수 빔형성 기법의 결과와 비교 검증하였다. When an array receives a signal with a frequency higher than the design frequency, there is an ambiguity in beamforming due to spatial aliasing. In order to overcome this problem, Abadi proposed frequency-difference beamforming. However, there is a constraint that the minimum frequency bandwidth is required according to the value of the difference frequency. In this paper, we propose a method to find the direction of the target signal with spatial aliasing based on the frequency-wavenumber spectrum combined with Radon transform. The proposed method can estimate the direction of the target without ambiguities when the signal has nonnegligible bandwidth. We tested the algorithm by simulating a broadband signal and verified the results with the frequency-difference beamforming method using SAVEX15 (Shallow Water Acoustic Variability EXperiment 2015)'s shrimp noise data.

Biological Activity of Bioactive Components from Acer ginnala Max.

최용화,Sung Soo Han,이현옥,백승화 대한화학회 2005 Bulletin of the Korean Chemical Society Vol.26 No.9

The sap of A. ginnala Max. has been used for treatment of stomachic and diarrhea.1 The plant, A. ginnala Max. (family Aceraceae) grows as a perennial herb and is widely distributed in Korea. Among the plants examined, Acer ginnala, lllicium and Cornus macrophylla exerted the most strong inhibitory activity on aldose reductase.2 Phyto- chemical studies of this plant have so far yielded poligalitol,3 acertannin,4,5 and polygagallin.6 A methanol solution of DPPH free radical was found to be stable for more than 60 min by spectrophotometry at 517 nm of an 80 g/mL solution. The radical scavenging effects of 45 medicinal plant extracts and fractions of A. ginnala were then measured spectrophotometrically for DPPH free radical. The control intensity (absorbance of extracts, fractions and pure compounds) was taken as 100%, and the percentage inten- sity was calculated. The concentration for 50% inhibition is shown in Tables 1 and 2. As shown in Table 1, twelve plant extracts examined in this study exhibited scavenging effects on DPPH free radical.1 The radical scavenging effects of twelve species was higher than all others in plants. A. ginnala Max. showed the strongest effects. The IC50 of this crude methanol extract was almost equivalent to BHA. The methanol extract of A. ginnala Max. was further partitioned with n-hexane, chloroform, ethyl acetate, n-butanol and water, successively and the ethyl acetate fraction had the strongest radical scavenging effect against DPPH free radical. This fraction was further purified to obtain two main bioactive compounds, acertannin (1) and methyl gallate (2) (Fig. 1). Acertannin (1) and methyl gallate (2) thus obtained were identified by comparison of their spectral data (TLC, MS, 1H and 13C-NMR, IR) with those published or by direct comparison with an authentic sample.2-5,7 Figure 1 showed the chemical structure of acertannin (1) and methyl gallate (2). Table 2 shows these two bioactive compounds, acertan- nin (1) and methyl gallate (2) are more effective than -tocopherol or BHA. Bioactive compounds (1 and 2) were found to have effective in vitro cytotoxic activity with IC50 values in the range 6.7-69.8 M when evaluated against tumor cell lines. Methyl gallate (2) was the main cytotoxic component in the extract with an IC50 of 6.70 M against skin melanoma cell lines (SK-MEL-2). Acertannin (1) was also cytotoxic with an IC50 of 22.12 M (Table 3). These compounds were found to have effective in vitro anti- microbial activity with MIC values in the range 50-1,600 g/mL when evaluated against microorganisms. The aim of our present work is to screen forty-five medicinal plants for antioxidant activity, and further identify two active compounds from A. ginnala Max. that show the biological activity.