Synthesis, structure analyses, and characterization of novel epigallocatechin gallate (EGCG) glycosides using the glucansucrase from Leuconostoc mesenteroides B-1299CB     

Moon YH  Lee JH  Ahn JS  Nam SH  Oh DK  Park DH  Chung HJ  Kang S  Day DF  Kim D 《Journal of agricultural and food chemistry》2006,54(4):1230-1237

In this study, three epigallocatechin gallate glycosides were synthesized by the acceptor reaction of a glucansucrase produced by Leuconostoc mesenteroides B-1299CB with epigallocatechin gallate (EGCG) and sucrose. Each of these glycosides was then purified, and the structures were assigned as follows: epigallocatechin gallate 7-O-alpha-D-glucopyranoside (EGCG-G1); epigallocatechin gallate 4'-O-alpha-D-glucopyranoside (EGCG-G1'); and epigallocatechin gallate 7,4'-O-alpha-D-glucopyranoside (EGCG-G2). One of these compounds (EGCG-G1) was a novel compound. The EGCG glycosides exhibited similar or slower antioxidant effects, depending on their structures (EGCG > or = EGCG-G1 > EGCG-G1' > EGCG-G2), and also manifested a higher degree of browning resistance than was previously noted in EGCG. Also, EGCG-G1, EGCG-G1', and EGCG-G2 were 49, 55, and 114 times as water soluble, respectively, as EGCG.  相似文献   

Prolyl endopeptidase inhibitory activity of unsaturated fatty acids     

Park YS  Jang HJ  Lee KH  Hahn TR  Paik YS 《Journal of agricultural and food chemistry》2006,54(4):1238-1242

Prolyl endopeptidase (PEP, EC 3.4.21.26) is widely distributed in various organs, particularly in the brains of amnestic patients. Evaluation of PEP levels in postmortem brains of Alzheimer's disease patients revealed significant increases in PEP activity, suggesting that a specific PEP inhibitor can be a good candidate for an antiamnestic drug. In this study, mono- and polyunsaturated fatty acids were investigated to determine their role as PEP inhibitors. Oleic, linoleic, and arachidonic acids, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) showed PEP inhibitory activities (IC50 values of 23.6 +/- 0.4, 43.8 +/- 1.8, 53.4 +/- 1.2, 99.4 +/- 1.2, and 46.2 +/- 1.0 microM, respectively), indicating that they were effective PEP inhibitors, with inhibition constant (Ki) values of 26.7 +/- 0.3, 51.0 +/- 0.7, 91.3 +/- 3.1, 247.5 +/- 2.6, and 89.0 +/- 2.3 microM, respectively. Oleic acid showed the highest PEP inhibitory activity. Dixon plots of PEP inhibition showed oleic, linoleic, and arachidonic acids, EPA, and DHA are noncompetitive inhibitors; despite higher IC50 values of these unsaturated fatty acids than strong natural inhibitors, they may have potential use in preventing memory loss.  相似文献   

Study on the nitric oxide scavenging effects of ginseng and its compounds     

Kang KS  Yokozawa T  Kim HY  Park JH 《Journal of agricultural and food chemistry》2006,54(7):2558-2562

In this study, an in vitro nitric oxide (*NO)-generating system was used to investigate the *NO-scavenging effects of methanolic extracts of white ginseng (Panax ginseng C.A. Meyer), red ginseng, and sun ginseng and several ginsenosides and phenolic compounds. Sun ginseng extract showed the strongest activity among the three ginseng extracts. None of the ginsenosides used in this experiment showed *NO-scavenging activity, but the phenolic compounds, such as p-coumaric and vanillic acids, and maltol inhibited *NO production in a concentration-dependent manner. Moreover, maltol levels markedly increased by heat processing. Therefore, the enhanced *NO-scavenging activity of ginseng by heat processing was closely related to phenolic acids and the increased content of maltol.  相似文献   

A strategy for annotating the human milk glycome     

Ninonuevo MR  Park Y  Yin H  Zhang J  Ward RE  Clowers BH  German JB  Freeman SL  Killeen K  Grimm R  Lebrilla CB 《Journal of agricultural and food chemistry》2006,54(20):7471-7480

Oligosaccharides in human milk represent a group of bioactive molecules that have evolved to be an abundant and diverse component of human milk, even though they have no direct nutritive value to the infant. A recent hypothesis proposes that they could be substrates for the development of the intestinal microflora and the mucosal immune system. The inability to determine the exact composition of these oligosaccharides limits research and the ability to understand their biological functions. Oligosaccharides isolated from the lipids and proteins of individual human milk samples were analyzed by a combination of techniques including microchip liquid chromatography mass spectrometry (HPLC-Chip/MS) and matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FT ICR MS). Accurate mass measurements obtained using an orthogonal time-of-flight (o-TOF) mass spectrometry provided oligosaccharide composition for approximately 200 individual molecular species. Comparison of HPLC-Chip/MS profiles from five different women revealed variations in milk oligosaccharide compositions. HPLC-Chip/MS profiling provides a method for routinely identifying milk oligosaccharides. Tandem MS in combination with exoglycosidase digestion provides unambiguous differentiation of structural isomers.  相似文献   

Flavonoids as mushroom tyrosinase inhibitors: a fluorescence quenching study     

Kim D  Park J  Kim J  Han C  Yoon J  Kim N  Seo J  Lee C 《Journal of agricultural and food chemistry》2006,54(3):935-941

Flavonoids, a group of naturally occurring antioxidants and metal chelators, can be used as tyrosinase inhibitors due to their formation of copper-flavonoid complexes. Thus, to investigate the underlying inhibition mechanism, a large group of flavonoids from several major flavones and flavonols were tested using fluorescence quenching spectroscopy. In addition, large differences in the tyrosinase inhibitory activities and chelating capacities according to the location of the hydroxyl group(s) in combination with the A and B rings in the flavonoids were confirmed. Accordingly, the major conclusions from this work are as follows: (i) The tyrosinase inhibitory activity is not only dependent on the number of hydroxyl groups in the flavonoids, (ii) the enzyme is primarily quenched by the hydroxyl group(s) of A and B rings on the ether side of the flavonoids, and (iii) the tyrosinase inhibitory activity of 7,8,3',4'-tetrahydroxyflavone is supported by a virtual model of docking with the mushroom tyrosinase, which depicts the quenching of the enzyme. The results also demonstrated that the dihydroxy substitutions in the A and B rings are crucial for Cu2+-chelate formation, thereby influencing the tyrosinase inhibitory activity.  相似文献   

Effect of far-infrared irradiation on catechins and nitrite scavenging activity of green tea     

Lee SC  Kim SY  Jeong SM  Park JH 《Journal of agricultural and food chemistry》2006,54(2):399-403

The processed green tea leaves were irradiated by far-infrared (FIR) at eight temperatures (80, 90, 100, 110, 120, 130, 140, and 150 degrees C) for 10 min. After FIR irradiation, green teas were prepared by soaking the leaves in boiling water, and the physicochemical characteristics of the green tea were determined. FIR irradiation at 90 degrees C increased total phenol contents of green tea from 244.7 to 368.5 mg/g and total flavanol contents from 122.0 to 178.7 mg/g, compared with non-irradiated control. FIR irradiation also significantly affected the amounts of epigallocatechin and epigallocatechin gallate. Nitrite scavenging activity also increased with increasing FIR irradiation until the temperature reached 110 degrees C. However, the overall color changes of green tea irradiated with FIR at 90 and 100 degrees C were negligible. These results indicate that the chemical quality of green tea is significantly affected by FIR irradiation temperature of the green tea leaves.  相似文献   

Cloning and characterization of a catechol-degrading gene cluster from 3,4-dichloroaniline degrading bacterium Pseudomonas sp. KB35B     

Kim YM  Park K  Kim WC  Shin JH  Kim JE  Park HD  Rhee IK 《Journal of agricultural and food chemistry》2007,55(12):4722-4727

  相似文献   

Cytotoxic and antitumor activities of thiosulfinates from Allium tuberosum L     

Park KW  Kim SY  Jeong IY  Byun MW  Park KH  Yamada K  Seo KI 《Journal of agricultural and food chemistry》2007,55(19):7957-7961

In this study we isolated crude thiosulfinates from Allium tuberosum L. using CH 2Cl 2 and then with silica gel column chromatography purified S-methyl methanthiosulfinate and S-methyl 2-propene-1-thiosulfinate from the crude thiosulfinates. Subsequently, in vitro cytotoxicities against human cancer cells and in vivo antitumor activities of the thiosulfinates were investigated. Their cytotoxicities were strong in human cancer cells, in the order of S-methyl 2-propene-1-thiosulfinate, crude thiosulfinates, and S-methyl methanthiosulfinate. When thiosulfinates were administered consecutively for 7 days at 10, 30, and 50 mg/kg ip, in mice, we found significant increases in the life spans of mice that had been inoculated with Sacorma-180 tumor cells. The crude thiosulfinates also induced apoptosis in MCF-7 cancer cells. These results suggest that thiosulfinates from Allium tuberosum L. inhibit the proliferation of cancer cells via apoptosis and have antitumor activities.  相似文献   

Detection of cerebral metabolites in a canine model of ischemic stroke using H magnetic resonance spectroscopy     

Byeong-Teck Kang  Dong-Pyo Jang  Jong-Hwan Lee  Dong-In Jung  Su-Hyun Gu  Chae-Young Lim  Young-Bo Kim  Fu-Shi Quan  Hyung-Joong Kim  Eung-Je Woo  Zang-Hee Cho  Hee-Myung Park   《Research in veterinary science》2009,87(2):300-306

Proton magnetic resonance spectroscopy (¹H MRS) provides in vivo biochemical information on tissue metabolites. The purpose of this study was to investigate the serial metabolic changes of ¹H MRS in the cerebrum of ischemic dogs. An ischemic stroke was induced in five health laboratory beagle dogs by permanent middle cerebral artery occlusion using a silicone plug. ¹H MRS was serially performed three times with a 1.5-T MR system: before, three days after and 10 days after the stroke. Immunohistochemical staining was performed to determine the expression of neuronal nuclei (NeuN) and glial fibrillary acidic protein (GFAP) at both the ipsilateral and contralateral cerebral cortex. Reduced levels of N-acetyl-asparate (p < 0.05), choline (Cho), creatine (Cr) and myo-inositol (mI), and a marked increase in the lactate (Lac) level (p < 0.01) were found at three days after the stroke. At 10 days after the stroke, the levels of Lac significantly increased (p < 0.01); however, the other metabolites were partially elevated. The changes of Cr, Cho and mI were not statistically significant (p > 0.05) when the before and after stroke values were compared. There was a significant loss of NeuN and GFAP immunoreactivity at the ischemic core. ¹H MRS may be to a useful diagnostic tool for the evaluation of ischemic stroke in dogs.  相似文献   

A DNA miniarray system for simultaneous visual detection of porcine circovirus type 1 (PCV1) and 2 (PCV2) in pigs     

An DJ  Song DS  Park JY  Park BK 《Veterinary research communications》2009,33(2):139-147

A miniarray system was developed for the simultaneous detection of porcine circovirus type 1 (PCV1) and type 2 (PCV2) in pigs. The system consists of a polymerase chain reaction (PCR) step to amplify target viral DNA, followed by detection of the amplified DNA using a membrane-anchored probe array and an avidin-alkaline phosphatase (Av-AP) indicator system. The lower limit of detection of PCV using the miniarray was 10^1.9 tissue culture infectious dose 50 (TCID₅₀)/ml and 10^2.08TCID₅₀/ml for PCV1 and PCV2, respectively, and 100 viral copies/μl for both PCV1 and PCV2. We validated the miniarray system using 141 lymph node specimens from pigs with suspected postweaning multisystemic wasting syndrome or porcine dermatitis and nephropathy syndrome. Of the 141 samples evaluated, 55 were identified as positive for PCV by the miniarray. Relative to in situ hybridization, the sensitivity and specificity of the miniarray was 100% and 98.9%, respectively. In contrast to other microarray systems, the miniarray does not require a DNA chip reader, since the results can be determined by visual inspection of colorized spots on a nylon membrane. This system represents an effective alternative method for the differential detection of PCV1 and PCV2 in pigs, as well as the maintenance of PCV-free cell lines and pre-screening of commercial vaccines for possible contamination.  相似文献