• 한국미생물·생명공학회지
• /
• 제38권1호
• /
• pp.24-31
• /
• 2010

본 연구는 제주 연안 해수로부터 분리된 항산화물질을 생산하는 해양 방선균의 천연해양항산화물질에 관한 연구이다. 균주 ACT-18은 16S rDNA 염기서열, 전자현미경을 이용한 형태학적 분석, 생리학적, 생화학적 특성 및 세포 지방산분석을 통하여 동정되었다. 분리균주 ACT-18은 Gram 양성, 호기성, 비운동성 포자, 배지상에서 substrate mycelia의 색이 어두운 초록색, aerial mycelia는 노란색의 회색을 나타내였다. 세포사이즈는 약 $0.5{\sim}1.0\;{\mu}m$였다. 16S rDNA 염기서열 분석결과 Gram 양성박테리아인 Streptomyces 종들과 그룹을 형성하였다. 지방산분석결과 주요 지방산은 $C_{15:0}$ anteiso(39.33%), $C_{16:1}$ cis 9(11.96%), $C_{16:0}$ (13.08%)과 $C_{17:0}$ anteiso(10.99%)로 분석되었다. Streptomyce sp. ACT-18의 배양액 메탄올 추출물의 항산화 활성은 electron spin resonance (ESR) spectrometer에 의한 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl, alkyl 라디컬 소거활성을 측정하여 나타내었다. 그 결과 배양액 메탄올 추출물의 DPPH 라디컬 소거활성은 0.1 mg/mL의 농도에서 46%의 라디컬 소거활성을 보였으며, Hydroxyl 라디컬 소거활성은 0.1 mg/mL에서 63%, alkyl 라디컬 소거활성은 0.1 mg/mL에서 39%의 소거 활성을 보였다.

• Bulletin of the Korean Chemical Society
• /
• 제28권12호
• /
• pp.2477-2480
• /
• 2007

MgAl2O4:Eu3+ red-light emitting powder phosphor was prepared at temperature as low as 500 oC within a few minutes by using the combustion route. The prepared powder was characterized by X-ray diffraction, scanning electron microscopy and Fourier-transform infrared spectrometry. The luminescence of Eu3+-activated MgAl2O4 shows a strong red emission dominant peak around 611 nm, which can be attributed to the 5D0-7F2 transition of Eu3+ ions from the synthesized phosphor particles under excitation (394 nm). Electron paramagnetic resonance (EPR) measurements at the X-band showed that no signal could be attributed to Eu2+ ions in MgAl2O4.

• Fisheries and Aquatic Sciences
• /
• 제14권3호
• /
• pp.179-185
• /
• 2011

The antioxidant activities of a methanolic extract of Eisenia bicyclis and its organic solvent fractions, including dichloromethane ($CH_2Cl_2$), ethyl acetate (EtOAc), n-butanol (n-BuOH), and water ($H_2O$) fractions, were investigated. Scavenging activities against DPPH, hydroxyl, superoxide anion, and peroxynitrite radicals were evaluated using electron spin resonance spectrometry; intracellular reactive oxygen species (ROS) were evaluated by a 2',7'-dichlorofluorescein diacetate assay using RAW264.7 mouse macrophages. The antioxidant activities of the individual fractions were: EtOAc>n-BuOH>$CH_2Cl_2$ >$H_2O$. The EtOAc fraction exhibited strong radical scavenging activity and a significantly reduced ROS level in RAW264.7 cells. Moreover, the phenolic contents of the extract and fractions followed the same order as their radical scavenging activities. Our results indicate that E. bicyclis is a valuable natural source of antioxidants that may be applicable to the functional food industry.

• Food Science and Biotechnology
• /
• 제18권2호
• /
• pp.374-378
• /
• 2009

Three physical methods, photostimulated luminescence (PSL), thermoluminescence (TL), and electron spin resonance (ESR), have been applied to detect the irradiation treatment for the non- and steamed sesame seed samples. PSL successfully screened the irradiated samples from the non-irradiated control by comparing their photon counts (PCs) with the lower (less than 700 count/60 sec) and upper threshold values (higher than 5,000 count/60 sec). TL signals were still detected in all irradiated samples even after steaming, which was reconfirmed with TL ratios [integrated area of $TL_1$ (the first glow)/$TL_2$ (the second glow)] through re-irradiation step. ESR spectrometry showed that radiation-induced cellulose radicals were detected in all the irradiated samples irrespective of steaming treatment. Identification of the irradiated sesame seeds was possible even after steaming by analyzing PSL, TL, and ESR.

• 대한화학회지
• /
• 제25권1호
• /
• pp.13-20
• /
• 1981

Iminoxyl biradical은 biradical spin probe로 액체결정에 주입시켜 그 결정의 director분포에 관한 역학적성질을 조사하는데 유용한 물질이다. 새로운 방법으로 iminoxyl biradical을 합성하는 과정에서 각 단계의 합성중간 생성물들을 녹는점측정과 NMR, IR, UV 및 Mass 등과 같은 분광학적인 방법으로 확인하였다. 최종 생성물인 iminoxyl biradical은 EPR 분광법으로 확인하고 두 spin간의 상호작용도 EPR peaks로 고찰하였다.

• ALGAE
• /
• 제32권1호
• /
• pp.75-86
• /
• 2017

Polysaccharides of marine algae exhibit different structural characteristics and interesting biological functions. In this study, crude polysaccharides (CP) of eleven Sri Lankan marine algae obtained through hot water extraction and ethanol precipitation were investigated for DPPH, alkyl, and hydroxyl radical scavenging activities using electron spin resonance spectrometry and for intracellular reactive oxygen species scavenging activity in the Chang liver cell line. Characterization of CPs was done by Fourier transform infrared (FTIR) spectroscopy and by analysis of the monosaccharide composition. Time-dependent density functional theory quantum-chemical calculations at the RB3LYP/6-31G(d,p) level for constructed dimeric units of the corresponding polysaccharides were used to resolve the FTIR spectra. CPs from Chnoospora minima showed the highest DPPH and alkyl radical scavenging activities and higher intracellular reactive oxygen species scavenging effects for both AAPH and $H_2O_2$ induced ROS production in "Chang" cells. The major polysaccharide constituent in C. minima CP was identified as fucoidan and it displayed a higher sulfate content. The degree of sulfation of these polysaccharides suggests a positive correlation with the observed antioxidant properties.

• Journal of Microbiology and Biotechnology
• /
• 제19권11호
• /
• pp.1319-1327
• /
• 2009

Marine red algae of genus Laurencia are becoming the most important resources to produce unique natural metabolites with wide bioactivities. However, reports related to Laurencia undulata, an edible species used as folk herb, are rarely found to date. In this research, 5-hydroxymethyl-2-furfural (5-HMF) was isolated and characterized by nuclear magnetic resonance (NMR) from Laurencia undulata as well as other marine algae. The following characteristics of 5-HMF were systematically evaluated: its antioxidant activities, such as typical free-radicals scavenging in vitro by electron spin resonance spectrometry (ESR) and intracellular reactive oxygen species (ROS) scavenging; membrane protein oxidation; oxidative enzyme myeloperoxidase (MPO) inhibition; as well as expressions of antioxidative enzymes glutathione (GSH) and superoxide dismutase (SOD) on the gene level using the polymerase chain reaction (PCR) method. The results demonstrated that 5-HMF could be developed as a novel marine natural antioxidant or potential precursor for practical applications in the food, cosmetic, and pharmaceutical fields.

• 한국해양바이오학회지
• /
• 제7권1호
• /
• pp.19-27
• /
• 2015

The objective of the current study was to evaluate the inhibitory and antioxidant activities of powdered katsuobushi (dried bonito) protein hydrolysates and their corresponding fractions. The powdered katsuobushi (dried bonito) hydrolysates were obtained by enzymatic hydrolysis using Alcalase, ${\alpha}$-chymotrypsin, Neutrase, pepsin, papain, and trypsin. The antioxidant efficacy of the respective hydrolysates were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, superoxide, and alkyl radical-scavenging activities. Among the hydrolysates, the peptic-derived hydrolysate exhibited the highest antioxidant activity compared to other enzymatic hydrolysates. Therefore, the peptic-derived hydrolysate was further analyzed, and was found to contain an active peptide with an amino acid sequence identified as Pro-Met-Pro-Leu-Asn-Ser-Cys (756 Da). The purified peptides from powdered katsuobushi (dried bonito) had an $EC_{50}$ value of $105.82{\mu}M$, and exhibited an inhibitory effect against DNA oxidation induced by hydroxyl radicals. Taken together, these results suggests that powdered katsuobushi (dried bonito) could be used as a natural antioxidant in functional foods and prevent oxidation reactions in food processing.

• Nutrition Research and Practice
• /
• 제5권6호
• /
• pp.495-502
• /
• 2011

In this study, antioxidant and free radical scavenging activities of the natural antioxidative compound, pyrogallol-phloroglucinol-6,6'-bieckol (PPB) isolated from brown algae, Ecklonia cava was assessed in vitro by measuring the radical scavenging activities (DPPH, alkyl, hydroxyl, and superoxide) using electron spin resonance (ESR) spectrometry, intracellular reactive oxygen species (ROS) scavenging activity, and DNA damage assay. According to the results of these experiments, the scavenging activity PPB against difference radicals was in the following order: DPPH, alkyl, hydroxyl, and superoxide radicals ($IC_{50}$; 0.90, 2.54, 62.93 and $109.05{\mu}M$). The antioxidant activities of PPB were higher than that of the commercial antioxidant, ascorbic acid. Furthermore, PPB effectively inhibited DNA damage induced by $H_2O_2$. These results suggest that the natural antioxidative compound, PPB, can be used by the natural food industry.

• Biomolecules & Therapeutics
• /
• 제21권4호
• /
• pp.270-276
• /
• 2013

Fucoxanthin is an important carotenoid derived from edible brown seaweeds and is used in indigenous herbal medicines. The aim of the present study was to examine the cytoprotective effects of fucoxanthin against hydrogen peroxide-induced cell damage. Fucoxanthin decreased the level of intracellular reactive oxygen species, as assessed by fluorescence spectrometry performed after staining cultured human HaCaT keratinocytes with 2',7'-dichlorodihydrofluorescein diacetate. In addition, electron spin resonance spectrometry showed that fucoxanthin scavenged hydroxyl radical generated by the Fenton reaction in a cell-free system. Fucoxanthin also inhibited comet tail formation and phospho-histone H2A.X expression, suggesting that it prevents hydrogen peroxide-induced cellular DNA damage. Furthermore, the compound reduced the number of apoptotic bodies stained with Hoechst 33342, indicating that it protected keratinocytes against hydrogen peroxide-induced apoptotic cell death. Finally, fucoxanthin prevented the loss of mitochondrial membrane potential. These protective actions were accompanied by the down-regulation of apoptosis-promoting mediators (i.e., B-cell lymphoma-2-associated ${\times}$ protein, caspase-9, and caspase-3) and the up-regulation of an apoptosis inhibitor (B-cell lymphoma-2). Taken together, the results of this study suggest that fucoxanthin defends keratinocytes against oxidative damage by scavenging ROS and inhibiting apoptosis.