Chang-Yeon Yu

Kangwon National University, Shunsen, Gangwon, South Korea

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Publications (52)14.43 Total impact

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    ABSTRACT: The objective of this study was to determine the biological activities of Sorglum bicolor extracts. Organic fractions, including n-Hexane, EtOAc, and n-BuOH fractions were obtained from the methanol extract of Sorglum bicolor M.. In DPPH radical scavenging activity, values of methanol extract and EtOAc fraction were exhibited and , respectively. Contents of total polyphenol and flavonoids in EtOAc fraction, which were much higher than those of other fractions, were 58.12 mg/g and 4.79 mg/g respectively. Also, effects of reducing power was strongly showed in EtOAc fraction. -Glucosidase and -amlyase inhibition activities were showed the higher effect in D.W. fraction (, ). In MTT assay in the AGS, HT29 and HCT116 cell lines were significantly higher in the n-BuOH fraction than in the other fractions at concentration of extracts.
    Preview · Article · Feb 2013
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    ABSTRACT: This study was investigated seed germination of Rheum undulatum L. depends on storage temperature (-20, and room temperature), germination temperature (5, 15, 25 and ) and a soaking treatment (no soaking, 2 days and 4 days). There was not much difference from the germination rate of R. undulatum L. in storage temperature conditions for 8 weeks. The highest of germination rate occurred over 80 percentage at . When R. undulatum L. was soaked with tap water for four days, the average values of germination velocity and germination day were represented of 1.7 ea/day and 1.68 days. These results may help our understanding of variations in germination characteristics for R. undulatum L. seeds treated under various germination conditions.
    Full-text · Article · Oct 2012

  • No preview · Article · Apr 2012
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    ABSTRACT: This study is part of research to develop the technology for managing major medicinal crops after harvest. We studied the optimal germination conditions of (Maxim.) Hemsl. The mean germination time (MGT) of seeds was higher after soaking for 4 days after storage at for 8 weeks, than with germination at (3 days). However, the germinative energy (GE) decreased as the number of days soaking increased. The greatest germination rate () was at with no soaking of seeds stored at for 8 weeks. Based on these results, we characterized the germination conditions of a major medicinal crop.
    Full-text · Article · Apr 2012

  • No preview · Article · Apr 2012
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    ABSTRACT: Morus alba (Mulberry) leaves were exposed to fermentation for varying amounts of time: no fermentation (0 min, MANF), medial fermentation (10 h, MAMF), and full fermentation (24 h, MAFF). The chemical compositions of the teas were determined and compared with those of commercial Camellia sinensis teas. The results showed that mulberry leaf teas contained significantly higher amounts of ash and fat than Camellia sinensis tea. Compared with Camellia sinensis teas, all mulberry leaf teas contained significantly more total free amino acids (24.26~54.25mg L-glutamic acid equivalent ), but the concentration of caffeine was relatively low for mulberry leaf teas. High thiamine, riboflavin, and niacin contents were found in all mulberry leaf teas, but ascorbic acid and pyridoxine were found at higher levels in Camellia sinensis teas than in mulberry leaf teas. Color measurements demonstrated that mulberry leaf tea infusions generally had lower (greenness) and (yellowness) values than Camellia sinensis tea infusions. All infusions exhibited low turbidity levels (less than 10%). The contents of total phenols were measured as 71.8 and 74.9mg 100 infusion in MANF and MAFF, respectively, but the MAMF tea infusion showed significantly lower total phenols (64.6mg 100 infusion). The total flavonoid contents of mulberry leaf tea infusions were lower (8.9~20.6mg 100 infusion) than those of Camellia sinensis teas and thus had lower antioxidant capacities (DPPH: 326.8~526.9 trolox equivalent and FRAP: 364.6~387.6 trolox equivalent ) than Camellia sinensis teas. The amounts of -aminobutyric acid (GABA) and rutin were higher in fermented mulberry leaf teas; the level of GABA increased with increasing fermentation time and the content was highest in MAFF, but rutin content was highest in MAMF.
    Full-text · Article · Aug 2011
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    ABSTRACT: Forty nine accessions of the Sorghum bicolor (L) Moench collected from different agronomical zone of Gangwondo province, Korea were characterized morphologically on field trial. Plant length, stem diameter, tiller number, ear type, ear length, ear width, leaves length, leaves width and leaf color differed significantly in the cultivated accessions. Out of forty nine test accessions, six accessions (12.2%) showed comparatively taller height, measuring more than 300 cm, while, other ten test accessions (20.4%) were measured from 200~300 cm. There were no significant differences in the diameter of stem in the collected test accessions (2~3 cm). Of the total test accession, seven accessions showed leaf length of over 70 cm, and twenty two test accession revealed leaf length between 60-70 cm. Forty nine of the collected test accessions showed narrow and short leaves with white mid vain. These results provided additional information for the breeding programs and conservation of Sorghum bicolor as a bio-energy crop.
    Full-text · Article · Jun 2011
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    ABSTRACT: This study was carried out to optimize the embryogenic callus induction and plant regeneration from mature seeds of Sorghum bicolor. The effect of growth regulators was investigated on formation of embryogenic callus. The highest frequency of embryogenic callus was observed when the mature seeds were cultured on B5 medium supplemented with 2 mg/L 2,4-Dichlorophenoxyacetic acid (2,4-D). The highest frequency of plant regeneration from embryogenic callus was observed on MS medium with 0.5 6-benzyl amino purine (BAP) and 0.25 indole-3-butyric acid (IBA) to optimize the shoot regeneration. High concentration of BAP (1 ) supplemented with IBA (0.25 ) was effective combination for shoot multiplication. MS medium supplemented with 1 IBA was found to be the most effective for inducing roots. Normal rooted plantlets were transferred to the greenhouse for hardening with over 90% survival rate. Hence, this reproducible protocol could be useful for mass propagation and genetic transformation of S. bicolor.
    Full-text · Article · Apr 2011
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    ABSTRACT: We isolated four compounds, fustin, gallic acid, 3′,4′,7-trihydroxyflavone, and fisetin from Rhus verniciflua. These compounds showed electron donation ability (87–94%) that was stronger than butylated hydroxyanisole (52%). Gallic acid (OD700 = 1.98) showed the highest reducing power, and the other isolated compounds (OD700 = 0.66–1.31) showed stronger activity than α-tocopherol (OD700 = 0.21). The ethyl-acetate fraction had the highest phenolic content (723 mg GAE/g), followed by the 80% ethanolic extract (597 mg GAE/g). For Gram-negative bacteria, fisetin had the most potent anti-bacterial activity (MIC = 8 μg/ml) against Escherichia coli. 3′,4′,7-Trihydroxyflavone (106%), the 80% ethanolic extract (101%), and ethyl-acetate (98%) had the most powerful α-glucosidase inhibitory effect at 50 μg/ml. R. verniciflua extracts have potential as functional food additives.
    No preview · Article · May 2010 · Food Chemistry
  • Ju-Sung Kim · Chang-Yeon Yu · Myong-Jo Kim

    No preview · Article · Mar 2010
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    In-Soo Bang · Chang-Yeon Yu · Jung-Dae Lim
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    ABSTRACT: Anthocyanin and polyphenolic compounds present in fruits of mulberry (Morus alba L.) were determined and the influence of temperature and UV irradiation on stability of the anthocyanin-copigment complex were investigated. The copigmentation substance selected in non-anthocyanin fraction from mulberry for the study included: phenolic acid (hydroxybenzoic acid) and flavonoid (quercetin-3-O--D-glucopyranoside). The copigmentation effect increased with the copigment content. UV irradiation had a stronger degradation effect on the copigmentation complex than heating at . The non-anthocyanin fraction of mulberry and isolated flavonoid (quercetin-3-O--D-glucopyranoside) from mulberry fruit predominated over other copigment substances.
    Full-text · Article · Jan 2010
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    ABSTRACT: The aim of this investigation was to examine the influence of extrusion on dietary fiber profile and the content of bioactive compounds, rutin and quercetin in young sprout, whole seed, and matured stem of Tartary buckwheat. WSI(water soluble index) is increased by a function of both screw profile and process temperature, compared to control in different parts of Buckwheat. Also, WSI of ME is increased more than 5.2 times in grain, compared to that of control. The effect of precooking by extrusion on the dietary fiber profile of buckwheat flour was evaluated. Precooking by extrusion significantly increased SDF in flour, although in most cases extrusion decrease in TDF a little. The thermo-mechanical treatment undergone by the buckwheat flour during extrusion led to redistribute part IDF fraction to SDF, leading to an increase in the latter. The content of rutin was increased about two fold in extruded flour of sprout, compared to in control. This increase maybe why these compounds are released from cell wall by high shear processing under high temperature.
    Full-text · Article · Jan 2009
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    ABSTRACT: Astragalus membranaceus has a long history of medicinal use in Chinese herbal medicine. It has been shown to have immunostimulant, tonic, antioxidant, antiperspirant, diuretic, anti-diabetic, expectorant properties, and a supplementary medicine during cancer therapy. In this study, we investigated the effect of anti-oxidation of Astragalus membranaceus root extract. The anti-oxidative activities of water, 80% methanol, and 100% methanol extracts from Astragalus membranaceus were analyzed by DPPH free radical scavenging activity, Superoxide dismutase-like activity, reducing power, and crude ash. The water extract demonstrated to be more effective than methanol extract for a DPPH radicals scavenging activities and reducing power. Superoxide dismutase-like activity showed higher efficiency in 80% methanol extract. Our results indicate that Astragalus membranaceus extracts could be used as a source of antioxidant ingredients in the food industry.
    Full-text · Article · Jan 2009
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    ABSTRACT: Fish protein hydrolysates (FPHs) with different degrees of hydrolysis by treatment with alcalase, pronase, flavourzyme and trypsin and isolated peptide were prepared from Hwangtae (yellow dried pollack, Theragra chalcogramma). Hwangtae protein hydrolysate was fractionated according to the molecular weight into six major types of APO1 (1.3 kDa), APO2 (1 kDa), APO3 (<1 kDa), APACE (<1 kDa), APG1 (70 kDa) and APG2 (70 kDa) isolated from the hydrolysate using consecutive chromatographic methods. Soluble peptide were produced from Hwangtae and evaluated for their nutritional and functional properties. Some functional properties of FPHs were assessed and compared with those of egg albumin or the soybean protein. APO2 had the highest nitrogen solubility value (94.2%), emulsion capacity and emulsion stability of the Alaska Pollack peptide ranged from 12.4 to 39.5 (mL of oil per 200 mg of protein) and 44.0% to 77.5%, respectively. Highest and lowest fat adsorption values were observed for APG1 (9.9 mL of oil per gram of protein) and APO3 (3.8 mL of oil per gram of protein), respectively.
    No preview · Article · Sep 2008 · Journal of Food Science and Nutrition
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    ABSTRACT: Hwangtae, dried Alaska pollack, is a major storage product in the fish processing industry. Hwangtae is prepared by removing the internal organs and drying outdoors during the cold witner months by allowing it to thaw during the daytime and re-freeze at night under sub-zero (-10oC) conditions and gradually dry from December until the next April for around 5 months from Myungtae. In this study, ground Hwangtae was hydrolyzed using two proteolytic enzymes (pepsin and alcalase) which produced five soluble active peptides from Hwangtae (yellowish dried Pollack, Theragra chalcogramma) protein. Two different peptides with strong antioxidative activity were isolated from the hydrolysate using consecutive chromatographic methods of Sephadex G-25 gel, ion-exchange chromatography on a Sepharose-Sephadex C-25 gel, and high-performance liquid chromatography. The isolated peptides, APO1 and APO2, were composed of 16 and 13 amino acid residues, respectively. Both peptides contained a Gly residue at the C-terminus and the repeating motif Gly-Pro-Hyp. The peptide with a molecular weight less than 1,000 Daltons (APACE) obtained from enzymatic hydrolysates of Hwangtae exhibited the highest ACE inhibitory activity. The APACE peptides was composed of 4 amino acid residues (Gly-Leu-Leu-Pro). These results suggest that Hwangtae hydrolysates could be a good source of peptides with ACE inhibitory activity. Biochemical analysis indicated that two 70 kDa peptides (APG1 and APG2) isolated from the hydrolysate had gelatinoytic activity, which was shown to be a calcium dependent protease type as showed by gelatin SDS PAGE.
    No preview · Article · Sep 2008 · Journal of Food Science and Nutrition
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    ABSTRACT: The chemical composition and content of essential oils extracted by ASTM standard D 889-93 method from the leaves of thirty introduced varieties in Perilla frutescens Britton var. japonica was investigated and compared. The oil was analysed by gas chromatography. More than forty compounds were found and thirteen compounds were identified. The major three constituents representing about of total oil were shown caryophyllene and 2 unknown oils in 25 varieties. The chemical composition and content had much differences in each of varieties. This result seemed to be corresponding to introduce that varieties had diverse essential oils.
    Preview · Article · Jan 2008
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    ABSTRACT: In order to study the content and composition of isoflavones retained in soybean seed component, obtained each component part the embryo, cotyledon and seed coat tissues of nine different soybean varieties were analyzed for 12 isoflavones using high performance liquid chromatography with photo diode array detector (HPLC-PDA) and were compared to each other. A total average concentration of isoflavone was 2887 μg g−1 in embryo, 575 μg g−1 in whole seed, 325 μg g−1 in cotyledon, and 33 μg g−1 in seed coat. With respect to each tissue of soybean varieties, isoflavone content was highest in Geomjeongkong 2 embryo (5701 μg g−1), Geomjeongolkong whole seed (1321 μg g−1), Heugcheongkong cotyledon (951 μg g−1), and Keunolkong seed coat (56 μg g−1). Isoflavone was least present in Keunolkong embryo (341 μg g−1), Hwaeomputkong whole seed (175 μg g−1), Seonheukkong cotyledon (81 μg g−1), and Seoklyangputkong seed coat (5 μg g−1). Overall, embryo and seed coat of all nine varieties contained isoflavones at the highest and lowest level, respectively. Isoflavones accumulated in the order of malonylglycoside, glycoside, acetylglycoside, and aglycon, among which malonylglycoside was the most abundant form ranging from 66% to 79% of the total isoflavone content in all three tissues. The embryo of cooked-with-rice soybean with black seed coat appears to be the best source of isoflavone.
    No preview · Article · Dec 2007 · Food Chemistry
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    ABSTRACT: An efficient regeneration system was developed using leaf, petiole, and internode explants. Highly embryogenic callus was obtained following cultivation on MS basal nutrient supplemented with 2 2,4-D. Globular, heart, torpedo and cotyledon shaped somatic embryo were produced from the surface of embryogenic callus. Direct shoot regeneration without intermediate callus formation has been achieved on MS medium supplemented NAA and BAP. The percentage of response varies with different concentration of auxin and cytokinin treated individually or in combination. The best shoot regeneration response (54.28%) and number of shoot per explant (12.67) were achieved on the medium supplemented with 0.1 NAA and 1 BAP. The regenerated shoot transformed into young plant when cultured into elongation and root induction medium. More than 90% of in vitro propagated plants could survive when transferred to the greenhouse for acclimation. This optimized regeneration system can be used for rapid shoot proliferation and genetic transformation.
    Full-text · Article · Jan 2007
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    ABSTRACT: Acer tegmentosum (Acereaceae) has been used a source of traditional medicines for the treatment of hepatic disorders in Korea. This research was conducted to determine biofunctional activities of A. tegmentosum stem extract and to identify its bioactive components. Methanolic extract from A. tegmentosum stem was partitioned by using organic solvents, including n-hexane, ethyl acetate, n-butanol, and water. Two compounds were isolated by using an ODS column chromatography from ethyl acetate soluble fraction shown to the strongest antioxidant activity () among the fractions. The isolated compounds were analyzed by and NMR, IR, UV/VIS, MS spectrum data and identified as catechin, alcohol was shown strong anti-lipid peroxidative activity. However, the compounds were not shown antimicrobial activities. In antimicrobial activity assays, ethyl acetate soluble fraction was effective to bacterial inhibition, such as Escherichia coli and Klebsiella pneumonia, with minimum inhibitory concentrations in . Otherwise, antifungal activity against Candida albicans was shown in n-hexane soluble fraction exhibiting of minimum inhibitory concentration. In anticomplementary activity assays, water soluble fraction was the most effective exhibiting 24% inhibitory activity.
    Preview · Article · Jan 2007
  • Maurice S.B. Ku · Cheng-wu Jin · Chang-yeon Yu · Dong-ha Cho
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    ABSTRACT: Transgenic rice plants expressing the maize phosphoenolpyruvate caboxylase (PEPC) and pyruvate, orthophosphate dikinase (PPDK) exhibit a higher photosynthetic capacity (up to 35%) than untransformed plants. Results obtained with transgenic rice plants grown in both controlled environment and field showed that they tend to have a superior photosynthetic capacity, especially under high light condition, and exhibit up to 35% increases in grain yield. Under photoinhibitory and photooxidative conditions, PEPC transgenic rice plants are capable of maintaining a higher photosynthetic rate, a higher photosynthetic quantum yield by PSII and a higher capacity to dissipate excess energy photochemically and non-photochemically than untransformed plants.
    No preview · Article · Jul 2006 · Journal of Biomedical Nanotechnology