Pohang Center for Evaluation of Biomaterials

Pohang, South Korea

Pohang Center for Evaluation of Biomaterials

Pohang, South Korea
Time filter
Source Type

Bajpai V.K.,Yeungnam University | Majumder R.,Yeungnam University | Park J.G.,Pohang Center for Evaluation of Biomaterials
Bangladesh Journal of Pharmacology | Year: 2016

Chromatographic techniques have significant role in natural products chemistry as well as contribute dramatically in the discovery of novel and innovative compounds of pharmaceutical and biomedical importance. This study focused on step-by-step visual demonstration of fractionation and isolation of biologically active plant secondary metabolites using column-chromatographic techniques. Isolation of bioactive compounds using column-chromatographic involves: a) Preparation of sample; b) Packing of column; c) Pouring of sample into the column; d) Elution of fractions; and e) Analysis of each fractions using thin layer chromatography. However, depending on nature of research, compounds can be further purified using high performance liquid chromatography (HPLC), and nuclear magnetic resonance (NMR) spectral analyses. © 2016, Bangladesh Pharmacological Society. All rights reserved.

Patra J.K.,Dongguk University | Lee S.-W.,Cooperation Technology | Park J.G.,Pohang Center for Evaluation of Biomaterials | Baek K.-H.,Yeungnam University
Journal of Food Biochemistry | Year: 2017

This study was conducted to extract essential oil from an edible seaweed, Undaria pinnatifida, and determine its chemical constituents, antibacterial and antioxidant potential. Gas chromatography and mass spectroscopy analysis of the U. pinnatifida essential oil (UPEO) revealed 26 volatile compounds comprising a total of 97.03%. Fatty acids such as tetradecanoic acid (31.32%) and hexadecanoic acid (22.39%) were present in the highest amount, followed by 3-hexen-1-ol (5.67%), erythritol (4.73%), 4-imidazolidinone (4.40%) and (9Z)-hexadec-9-enoic acid (4.37%). UPEO displayed potent antibacterial activity (9.5–11.0 mm inhibition zone), an MIC of 12.5–25.0 mg/mL and an MBC of 25.0 mg/mL. UPEO also exhibited strong hydroxyl radical scavenging (IC50 85.54 µg/mL), reducing power (IC0.5 178.82 µg/mL) and superoxide radical scavenging (IC50 260.89 µg/mL) potential. Taken together, these results indicate that UPEO could be an economical and safe resource for natural antioxidant and antibacterial compounds that can be utilized in food processing, cosmetics and pharmaceutical sectors. Practical Applications: Seaweeds are a rich source of natural bioactive compounds with various medicinal properties. The essential oils extracted from an edible seaweed, U. pinnatifida, could serve as an alternative source of natural antioxidant compounds with the potential for use as food additives and in food preservation and cosmetics. Use of this compound could minimize the use of synthetic antioxidant compounds that trigger health hazards. Furthermore, the bioactive compounds present in the UPEO could serve as a source of natural antibiotics against both Gram positive and Gram negative pathogenic bacteria. © 2016 Wiley Periodicals, Inc.

Shin J.-C.,Pohang Center for Evaluation of Biomaterials | Shin J.-C.,Kyungpook National University | Jung H.-Y.,Pohang Center for Evaluation of Biomaterials | Jung H.-Y.,Pohang University of Science and Technology | And 5 more authors.
Biochemical and Biophysical Research Communications | Year: 2013

Melatonin is secreted during the hours of darkness and is thought to influence the circadian and seasonal timing of a variety of physiological processes. AANAT, which is expressed in the pineal gland, retina, and various other tissues, catalyzes the conversion of serotonin to N-acetylserotonin and is the rate-limiting enzyme in the biosynthetic pathway of melatonin. The compounds that modulate the activity of AANAT can be used to treat patients with circadian rhythm disorders that are associated with specific circadian rhythm alterations, such as shift work disorder. In the present study, we screened modulators of AANAT activity from the water extracts of medicinal plants. Among the 267 tested medicinal plant extracts, Myricae Cortex (Myrica rubra), Perillae Herba (Perilla sikokiana), and Eriobotryae Folium (Eriobotrya japonica) showed potent inhibition of AANAT activity. Myricetin (5,7,3',4',5'-pentahydroxyflavonol), a main component of the Myricae Cortex, strongly inhibited the activity of AANAT and probably block the access to the substrate by docking to the catalytic residues that are important for AANAT activity. Myricetin significantly decreased the nocturnal serum melatonin levels in rats. In addition, the locomotor activity of rats treated with myricetin decreased during the nighttime and slightly increased throughout the day. These results suggest that myricetin could be used as a therapy to increase nighttime alertness by changing the circadian rhythm of serum melatonin and locomotor activity. © 2013 Elsevier Inc.

Lee K.-H.,Pohang University of Science and Technology | Woo K.-C.,Pohang University of Science and Technology | Kim D.-Y.,Pohang University of Science and Technology | Kim T.-D.,Korea Research Institute of Bioscience and Biotechnology | And 5 more authors.
Molecular and Cellular Biology | Year: 2012

The mouse PERIOD1 (mPER1) protein, along with other clock proteins, plays a crucial role in the maintenance of circadian rhythms. mPER1 also provides an important link between the circadian system and the cell cycle system. Here we show that the circadian expression of mPER1 is regulated by rhythmic translational control ofmPer1 mRNA together with transcriptional modulation. This time-dependent translation was controlled by an internal ribosomal entry site (IRES) element in the 5' untranslated region (5'-UTR) ofmPer1 mRNA along with the trans-acting factor mouse heterogeneous nuclear ribonucleoprotein Q (mhnRNP Q). Knockdown of mhnRNP Q caused a decrease in mPER1 levels and a slight delay in mPER1 expression without changing mRNA levels. The rate of IRES-mediated translation exhibits phase-dependent characteristics through rhythmic interactions betweenmPer1 mRNA and mhnRNP Q. Here, we demonstrate 5'-UTR-mediated rhythmicmPer1 translation and provide evidence for posttranscriptional regulation of the circadian rhythmicity of core clock genes. © 2012, American Society for Microbiology.

Lee H.,Inha University | Oh E.-T.,Inha University | Choi B.-H.,Inha University | Choi B.-H.,Pohang Center for Evaluation of Biomaterials | And 5 more authors.
Scientific Reports | Year: 2015

Oxygen and glucose deprivation (OGD) due to insufficient blood circulation can decrease cancer cell survival and proliferation in solid tumors. OGD increases the intracellular [AMP]/[ATP] ratio, thereby activating the AMPK. In this study, we have investigated the involvement of NQO1 in OGD-mediated AMPK activation and cancer cell death. We found that OGD activates AMPK in an NQO1-dependent manner, suppressing the mTOR/S6K/4E-BP1 pathway, which is known to control cell survival. Thus, the depletion of NQO1 prevents AMPK-induced cancer cell death in OGD. When we blocked OGD-induced Ca 2+ /CaMKII signaling, the NQO1-induced activation of AMPK was attenuated. In addition, when we blocked the RyR signaling, the accumulation of intracellular Ca 2+ and subsequent activation of CaMKII/AMPK signaling was decreased in NQO1-expressing cells under OGD. Finally, siRNA-mediated knockdown of CD38 abrogated the OGD-induced activation of Ca 2+ /CaMKII/AMPK signaling. Taken together, we conclude that NQO1 plays a key role in the AMPK-induced cancer cell death in OGD through the CD38/cADPR/RyR/Ca 2+ /CaMKII signaling pathway.

Choi U.K.,Pohang Center for Evaluation of Biomaterials | Bajpai V.K.,Daegu University
Food and Chemical Toxicology | Year: 2010

This study was conducted to evaluate the effect of dark and light conditions on the quality characteristics of whole soybean meju, a Koran soybean fermentation starter, made by germinated soybeans. The sprouting rates of soybeans under dark and light conditions after 24 h were 25.6 ± 1.2% and 20.5 ± 1.5%, respectively and reaching to a level of 99.4 ± 0.4% and 98.9 ± 0.5%, respectively at 60 h. The pH, moisture contents and amino-type nitrogen contents had no significant differences under dark and light conditions, however, the contents were significantly different as compared to control. Also there was a significant difference in the color change values of whole soybean meju under dark and light conditions. The compositions of total organic acids in MNG, MGD and MGL were noted to be 942.2 ± 111.0, 1075 ± 120.2 and 1019 ± 108.1 mg%, respectively. However, no significant differences were observed in free amino acid contents of MNG, MGD and MGL. It was observed that isoflavone contents were significantly differed in MGD and MGL as compared to MNG. © 2009 Elsevier Ltd. All rights reserved.

Lim S.-I.,Korea Food Research Institute | Cho C.-W.,Korea Food Research Institute | Choi U.-K.,Pohang Center for Evaluation of Biomaterials | Kim Y.-C.,Korea Food Research Institute
Journal of Ginseng Research | Year: 2010

Ethanol and water extracts of white and fermented ginseng were prepared and their ginsenoside composition and antioxidant effects were assessed. The main ginsenosides in white ginseng were Rb1 > Re > Rg1, and those in fermented ginseng were Rb2 + Rb3 > Rd > Rg1. Ginsenosides Rd and Rg3 in fermented ginseng were enriched 11 and 58 times, respectively, over that in white ginseng through fermentation with five Bacillus spp. The greatest levels of 2-deoxyribose and superoxide anion dismutase-like activities were found in 50% ethanol extracts of fermented ginseng. Thus, these data suggest that white ginseng has the greatest free radical scavenging activity and that fermented ginseng has the highest antioxidant activity. © The Korean Society of Ginseng.

Choi U.K.,Pohang Center for Evaluation of Biomaterials
International journal of molecular sciences | Year: 2010

This study was undertaken to optimize the conditions for the extraction of antibacterial activity of Perilla frutescens var. acuta leaf against Pseudomonas aeruginosa KCTC 2004 using the evolutionary operation-factorial (EVOP) design technique. Increased antibacterial activity was achieved at higher extraction temperatures and with a longer extraction time. Antibacterial activity was not affected by differing ethanol concentration in the extraction solvent. The maximum antibacterial activity of ethanolic extract of P. frutescens var. acuta leaf against P. aeruginosa, determined by the EVOP factorial technique, was obtained at an extraction temperature of 80 °C (R = -0.800(**)), 26 h (R = -0.731(**)) extraction time, and 50% (R = -0.075) ethanol concentration. The population of P. aeruginosa also decreased from 6.660 log CFU/mL in the initial set to 4.060 log CFU/mL in the third set. Also, scanning electron microscopy study of the ethanolic extract of P. frutescens var. acuta revealed potential detrimental effects on the morphology of P. aeruginosa.

Choi U.-K.,Pohang Center for Evaluation of Biomaterials | Lee O.-H.,Kyonggi University | Yim J.H.,Korea Food Research Institute | Cho C.-W.,Korea Food Research Institute | And 3 more authors.
International Journal of Molecular Sciences | Year: 2010

Dandelion (Taraxacum officinale), an oriental herbal medicine, has been shown to favorably affect choleretic, antirheumatic and diuretin properties. Recent reports have indicated that excessive oxidative stress contributes to the development of atherosclerosis-linked metabolic syndrome. The objective of this current study was to investigate the possible hypolipidemic and antioxidative effects of dandelion root and leaf in rabbits fed with a high-cholesterol diet. A group of twenty eight male rabbits was divided into four subgroups; a normal diet group, a high-cholesterol diet group, a high-cholesterol diet with 1% (w/w) dandelion leaf group, and a high-cholesterol diet with 1% (w/w) dandelion root group. After the treatment period, the plasma antioxidant enzymes and lipid profiles were determined. Our results show that treatment with dandelion root and leaf positively changed plasma antioxidant enzyme activities and lipid profiles in cholesterol-fed rabbits, and thus may have potential hypolipidemic and antioxidant effects. Dandelion root and leaf could protect against oxidative stress linked atherosclerosis and decrease the atherogenic index. © 2010 by the authors; licensee Molecular Diversity Preservation International.

Choi B.-H.,Nanyang Technological University | Choi B.-H.,Pohang Center for Evaluation of Biomaterials | Chakraborty G.,Nanyang Technological University | Baek K.,Kyung Hee University | And 2 more authors.
Experimental and Molecular Medicine | Year: 2013

Here, we report that B-cell lymphoma 2 (Bcl-2) is a novel target molecule of aspirin in breast cancer cells. Aspirin influenced the formation of a complex by Bcl-2 and FKBP38 and induced the nuclear translocation of Bcl-2 and its phosphorylation. These events inhibited cancer cell proliferation and subsequently enhanced MCF-7 breast cancer cell apoptosis. Bcl-2 knockdown using small interfering RNA (siRNA) delayed apoptotic cell death, which correlated with increased proliferation following aspirin exposure. In contrast, Bcl-2 overexpression enhanced the onset of aspirin-induced apoptosis, which was also associated with a significant increase in Bcl-2 phosphorylation in the nucleus. Therefore, this study may provide novel insight into the molecular mechanism of aspirin, particularly its anticancer effects in Bcl-2-and estrogen receptor-positive breast cancer cells. © 2013 KSBMB.

Loading Pohang Center for Evaluation of Biomaterials collaborators
Loading Pohang Center for Evaluation of Biomaterials collaborators