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        검색결과 11

        1.
        2018.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study examined the changes in antioxidant activity and contents of phenolic compounds inblanched, steamed, and autoclaved burdock root (BR). The total polyphenolic and flavonoids contents of raw and cooked BR were determined spectrophotometrically. The antioxidant activity of BR was measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2- azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and oxygen radical absorbance capacity (ORAC) assays. The main phenolic compounds in BR were quantified by HPLC (high performance liquid chromatography). Both blanching and steaming treatments significantly increased the antioxidant activities of BR in all groups (5 min, 15 min, and 30 min), whereas in autoclaving treatment, the 30 min treatment only showed an increase in the antioxidant activities of BR. The 30 min blanched BR exhibited the strongest DPPH and ABTS radical scavenging activities and possessed the highest total polyphenol and flavonoid phenolic contents. The 15 min-steamed BR showed the highest ORAC value. The main phenolic compound of the 15 min-steamed BR was CGA (chlorogenic acid). These results suggest that heat cooking methods, such as blanching and steaming, improve the antioxidant activity of BR by increasing the concentration of phenolic compounds.
        4,000원
        2.
        2007.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 내분비계 장애물질으로 알려져 있고, 플라스틱 제품의 가소제로 사용되고 있는 di-(2-ethylhexyl) phthalate (DEHP)가 흰쥐의 간세포 미세구조와 간조직내 metallothionein (MT)의 발현 양상에 미치는 영향을 조사하였다. DEHP는 흰쥐 간세포의 미세구조와 MT 발현에 영향을 주었다. 실험군의 경우 조면소포체가 발달하고, 미토콘드리아가 증가하며 리소솜 혹은 퍼옥시좀들이 증가하는 경향을 나타냈다. 한편, MT
        4,000원
        3.
        2002.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        시중에 유통되고 있는 녹차중의 catechin류에 대하여 열수추출 및 HPLC 분석을 통하여 함량을 조사하고 이를 효율적으로 이용하기 위하여 pH조건이 녹차 catechin류의 안정성에 미치는 영향에 대하여 분석하였다. 시판 중인 전남 보성산 녹차의 catechin류 함량은 (+)-catechin > (-)-EGCg > (-)-EGC > (-)-EC > (-)-ECg 순으로 추출되었고 Total catechin류의 함량은 103.72 ㎎/g이었다. 녹차에서 분리·정제되어진 catechin류인 (+)-catechin, (-)-EC, (-)-ECg, (-)-EGCg를 pH 3∼11에 대한 안정성을 흡광도측정장치를 이용하여 측정하였다. 그 결과 catechin류의 pH에 대한 영향을 최대흡수파장 및 흡광도 변화로 보면 pH가 높을수록 (+)-catechin과 (-)-EC은 흡광도가 증가되었고, (-)-ECg와 (-)-EGCg는 최대흡수파장이 증가되었다. 또한 7일간 실온에서 저장하면서 기간에 따른 변화를 살펴본 결과에서 산성조건에서는 큰 변화가 없지만 알칼리조건에서는 흡광도가 증가되었다. (+)-catechin과 (-)-EC은 알칼리조건에서 흡수파장 400∼430 ㎚에서 저장기간이 길수록 흡광도가 증가되었다. 이는 녹차의 갈변과 관계가 있을 것으로 생각되었다. 이상의 결과로, 녹차 Catechin 유도체의 pH 및 저장기간에 대한 영향은 ECg, EGCg에 gallic acid의 결합에 의한 것으로 생각되고, C, EC의 불안정은 중합반응으로 생각된다. 녹차 catechin 류는 대부분 산성에서 저장기간이 길고 안정한 것으로 나타났으나 생리활성이 강한 (-)-EGCg는 산성에서도 불안정한 것으로 나타났다. 결론적으로 녹차의 기능성 성분을 효율적으로 이용하기 위해서는 pH를 낮게 유지하여야 할 것으로 사료되어진다.
        4,000원
        4.
        2000.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Lithospermum erythrorhyzon has been used as a red fooddye and traditional Chinese medicine to treat wounds, skin diseases and burns. Platelet activation plays an important role in thrombosis and haemostasis. Here, we studied the inhibition of platelet activation and its active compound from the root of Lithospermum erythrorhyzon. Its ethyl acetate extract inhibited the aggregation of washed rabbit platelets induced by collagen or thrombin. Five naphthoquinone pigments, shikonin, acetylshikonin, isobutylshikonin, α-methyl-n-butylshikonin and (β,β-dimethylacrylshikonin were isolated by means of high pressure liquid chromatography. The structures were determined by comparison of their proton nuclear magnetic resonance spectra. The potency of their inhibition was in the following order : β,β-dimethylacrylshikonin≥α-methyl-n-butylshikonin$gt;isobutylshikonin$gt;acetylshikonin$gt;shikonin. It is suggested that the size of the aliphatic hydroxy group of shikonin is important for the enhancement of potency.
        4,000원
        5.
        1998.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Platelet activation is originated by the intracellular or/and extracellular Ca^(2+). Agonist-induced Ca^(2+) entry through a plasma-membrane pathway has been reported repeatedly, but the mechanisms has proven harder to elucidate. Recently, a number of natural products have been isolated from medicinal plants and marine organisms and have proved to be useful chemical tools for resolving the mechanism of cellular functions. In an attempt to understand the mechanism of platelet activation in Bupleuri Radix, we have studied some aspects of the isolation of active components and their dependence of external Ca^(2+) on platelet activation. Acetone extract of Bupleuri Radix has the most activity on platelet activation and it's active components were identified as saikosaponin a and d. Their optimal concentration was respectively 20 ug/ml and 5 ug/ml and their platelet activation was not dependent on external Ca^(2+), whereas optimal concentration of each agonist was arachidonic acid (10 uM), collagen (10 ug/ml), thrombin (0.1 unit/ml), PAF (5 uM), PMA (5 uM), ionophore A23187 (2 uM) and their dependence of external Ca^(2+) on platelet activation appeared to thrombin$gt;collagen≥PAF$gt;PMA$gt;arachdonic acid$gt;ionophore A23187. These results suggest that saikosaponin is different from each agonists in the dependence of external Ca^(2+) on platelet activation.
        4,000원
        6.
        1997.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        For the purpose of isolation and screening of tyrosinase inhibitory activity from edible mushrooms, Pleurotus ostreatus, Auricularia auricula judge, Umbilicaria esculenta, Agaricus bisporus, Flammuline velutipes, Lentinus edodes, Ganoderma lucidum, and Coriolus uersicolor were examined by tracing inhibitory activities against tyrosinase, utilizing L-3,4-dihydroxyphenylalanine (L-DOPA) as a substrate. Among the eight edible mushrooms tested, Umbilicaria esculenta showed potent enzyme inhibitory activities above 78.4% against tyrosinase in ethylacetate (EtOAc) extracts. Ganoderma lucidum and Agaricus bisporus showed inhibitory activities of 67.3% and 51.5% in water extracts. EtOAc extracts of Umbilicaria esculenta was fractionated from silicagel column chromatography and one fraction showed the most inhibitory activity of 60.9%. The three bands (Rf=0.38, 0.27, 0.19) were isolated from preparative TLC of the fraction for purification and identified as mixtures of orsellinate, methyl orsellinate, methyl lecanorate, and methyl gyrophorate by high pressure liquid chromatography (HPLC), ultravisible spectrophotometer (UV), mass spectrophotometer (Mass), nuclear magnetic resonance spectrometer (NMR).
        4,000원
        7.
        1996.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The isolation and chemical characterization of yellow food pigments from Monascus purpureus were studied according to the compositions of media. Monascus yellow pigments were isolated and purified by solvent fractionation, silicagel column chromatography, TLC and HPLC. The retention time of Monascus yellow pigments isolated by HPLC was respectively 5 min(I) and 9 min(II) at the yeast malt extract agar(YMA) media and was respectively 4.6 min(III), 5 min(I) 5.7 min(IV), 8.3 min(V), 9 min(II) and 10.7 min(VI) at the malt extract agar (MEA) media. The structure of monascin(I), ankaflavin(II), 6,11-dihydrorubropunctatin(III), 6,11-dihydromonascorubrin(V) and unknown compounds(IV, VI) was elucidated by EI-Mass, H' and C'9 NMR, UV-visible spectrnmeter. Therefore, it was suggested that 6,11-dihydrorubropunctatin (III) and 6,11-dihydromonascorubrin(V) are new intermediates of Monascus yellow pigments.
        4,000원
        8.
        1995.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Incidents of seafood poisoning and massive fish kills have been rapidly increasing in both frequency and geographical distribution and the socioeconomic impacts brought by those incidents. However, the biological origins of those marine toxins have not been well clarified. Most of the marine organisms investigated are filter-feeders, which accumulate toxins from their food and/or their symbiotic microalgae. We have examined the action on rabbit platelets of marine toxins isolated from cultured dinoflagellates and sponge collected at Okinawa. Maitotoxin (MTX) is a water-soluble toxin isolated from the cultured dinoflagellate Gambierdiscus toxicus which causes a seafood poisoning in tropical regions. Zooxanthellatoxin A (ZT-A) was isolated from extracts of cultured symbiotic dinoflagellate Symbiodinium sp. (socalled zooxanthella) from flatworms of the genus Amphiscolops collected at Okinawa. Theonezolide A (TZ-A) was isolated from the Okinawan marine sponge Theonella sp. MTX caused a disaggregation and a dissolution of large aggregates. ZT-A caused a dissolution of small aggregates followed by a increment of light trasmission. TZ-A caused an initial and transient shape change followed by a sustained aggregation and a increment of large aggregates. In conclusion, marine toxins exert unique patterns on the light trasmission and the size of aggregates in rabbit platelets by their concentrations and kinds
        4,000원
        9.
        2016.10 KCI 등재 서비스 종료(열람 제한)
        Background: We investigated the optimal aqueous extraction conditions for recovery of high yields of total phenolic compounds from roots of Arctium lappa L. (burdock, Asteraceae), and we compared their antioxidant capacity.Methods and Results: The antioxidant activity of the extracts was tested using 2,2-diphenyl-1-picrylhydrazyl, 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)-diammonium salt, and oxygen radical absorbance capacity assays. In addition, the major phenolic compounds present in the extracts were determined by high performance liquid chromatography analysis. Our results suggest that the roasted burdock 100°C, 15 min extract exhibited the strongest radical scavenging activity and possessed the highest concentration of phenolic compounds. The polyphenol content of both dried burdock and roasted burdock significantly increased with increase in the extraction temperature and time.Conclusions: These results indicated a relationship between phenolic compound levels in burdock and their free radical scavenging activities. This suggests that phenolic compounds significantly increase the antioxidant potential of burdock extracts.
        10.
        2012.12 KCI 등재후보 서비스 종료(열람 제한)
        본 연구는 정서적 내용이 포함된 이야기의 반복적 경험이 유아의 정서지능에 미치는 효과가 어떠한지 알아보는데 그 목적이 있었다. 이를 위해 충청북도 청주시에 소재한 S어린이집 만 5세반 2개 학급의 유아 40명(실험집단 20명, 통제집단 20명)을 대상으로 연구를 실시하였다. 실험집단 유아들은 이야기의 반복적 경험을 하였으며, 실험처치는 9주동안 1주에 8회씩 총 72회 실시하였다. 이야기의 반복적 경험이 유아의 정서지능에 미치는 효과가 어떠한지 알아보기 위해 교사용 유아 정서지능 평정도구로 검사한 집단 간 사전 점수와 사후 검사의 증가분을 t검증하여 분석하였다. 그 결과 실험집단 유아들의 모든 정서지능 하위요소인 자기인식능력, 자기조절능력, 타인인식능력, 타인조절능력이 유의미하게 증진되었다. 본 연구 결과를 통해 이야기의 반복적 경험은 유아의 정서지능을 증진시키는데 효과가 있는 것을 알 수 있었다.
        11.
        2012.08 KCI 등재 서비스 종료(열람 제한)
        Nitrate contamination of water environments can create serious problems such as eutrophication of rivers. Conventional biological processes for nitrate removal by heterotrophic denitrification often need additional organic substrates as carbon sources and electron donors. We tried to accelerate biological denitrification by using bioelectrochemical reactor (BER) in which electrode works as an electron donor. Denitrification activity of 8 environmental samples from various sediments, soils, groundwaters, and sludges were tested to establish an efficient enrichment culture for BER. The established enrichment culture from a soil sample showed stable denitrification activity without any nitrite accumulation. Microbial community analysis by using PCR-DGGE method revealed that dominant denitrifiers in the enrichment culture were Pantoea sp., Cronobacter sakazakii, and Castellaniella defragrans. Denitrification rate (0.08 kg/m3·day) of the enrichment culture in BER with electrode poised at -0.5 V (vs Ag/AgCl) was higher than that (2.1×10-2kg/m3·day) of BER without any poised potential. This results suggested that biological denitrification would be improved by supplying potential throughout electrode in BER. Further research using BER without any organic substrate addition is needed to apply this system for bioremediation of water and wastewater contaminated by nitrate.