Acetyl- and butyrylcholinesterase inhibitory activities of sterols and phlorotannins from Ecklonia stolonifera     

Na Y Yoon  Hae Y Chung  Hyeung R Kim  Jae E Choi 《Fisheries Science》2008,74(1):200-207

ABSTRACT:   As part of this study on the isolation of cholinesterase inhibitors from natural marine products, the bioactivity of the ethanolic extracts from 27 Korean seaweeds were screened using acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory assays. Ecklonia stolonifera exhibited promising inhibitory properties against both AChE and BChE. Bioassay-guided fractionation of the active n -hexane and ethyl acetate (EtOAc) soluble fractions, obtained from the ethanolic extract of E. stolonifera , resulted in the isolation of the sterols; fucosterol ( 1 ) and 24-hydroperoxy 24-vinylcholesterol ( 2 ), from the n -hexane fraction and the phlorotannins; phloroglucinol ( 3 ), eckstolonol ( 4 ), eckol ( 5 ), phlorofucofuroeckol-A ( 6 ), dieckol ( 7 ), triphlorethol-A ( 8 ), 2-phloroeckol ( 9 ) and 7-phloroeckol ( 10 ), from the EtOAc fraction. Of these, compounds 2 , 9 and 10 were isolated from E. stolonifera for the first time. Compounds 4 – 7 , 9 and 10 exhibited inhibitory potential against AChE, with 50% inhibition concentration (IC₅₀) values of 42.66 ± 8.48, 20.56 ± 5.61, 4.89 ± 2.28, 17.11 ± 3.24, 38.13 ± 4.95 and 21.11 ± 4.16 μM, respectively; whereas, compounds 1 , 2 , 4 and 6 were found to be active against BChE, with IC₅₀ values of 421.72 ± 1.43, 176.46 ± 2.51, 230.27 ± 3.52 and 136.71 ± 3.33 μM, respectively. It has been suggested that the inhibition of these enzymes by the sterols and phlorotannins derived from marine brown algae could be a useful approach for the treatment of Alzheimer's disease.  相似文献   

Effects of green tea polyphenol (-)-epigallocatechin-3-gallate on newly developed high-fat/Western-style diet-induced obesity and metabolic syndrome in mice     

Chen YK  Cheung C  Reuhl KR  Liu AB  Lee MJ  Lu YP  Yang CS 《Journal of agricultural and food chemistry》2011,59(21):11862-11871

The aim of this study was to investigate the effects of (-)-epigallocatechin-3-gallate (EGCG) on newly developed high-fat/Western-style diet-induced obesity and symptoms of metabolic syndrome. Male C57BL/6J mice were fed a high fat/Western-style (HFW; 60% energy as fat and lower levels of calcium, vitamin D(3), folic acid, choline bitartrate, and fiber) or HFW with EGCG (HFWE; HFW with 0.32% EGCG) diet for 17 wks. As a comparison, two other groups of mice fed a low-fat diet (LF; 10% energy as fat) and high-fat diet (HF; 60% energy as fat) were also included. The HFW group developed more body weight gain and severe symptoms of metabolic syndrome than the HF group. The EGCG treatment significantly reduced body weight gain associated with increased fecal lipids and decreased blood glucose and alanine aminotransferase (ALT) levels compared to those of the HFW group. Fatty liver incidence, liver damage, and liver triglyceride levels were also decreased by the EGCG treatment. Moreover, the EGCG treatment attenuated insulin resistance and levels of plasma cholesterol, monocyte chemoattractant protein-1 (MCP-1), C-reactive protein (CRP), interlukin-6 (IL-6), and granulocyte colony-stimulating factor (G-CSF). Our results demonstrate that the HFW diet produces more severe symptoms of metabolic syndrome than the HF diet and that the EGCG treatment can alleviate these symptoms and body fat accumulation. The beneficial effects of EGCG are associated with decreased lipid absorption and reduced levels of inflammatory cytokines.  相似文献   

A Laboratory Column Study on the Biodegradation of Toluene and Methyl tert–Butyl Ether: The Effect of Substrate Interactions   总被引：1，自引：0，他引：1  

Chung  Seung-Gun  Kim  Dong-Ju  Lee  Sang-Hyup  Choi  Jae-Woo 《Water, air, and soil pollution》2013,224(4):1-8

Soil vapor extraction (SVE) is one of the most effective remediation technologies for soil and groundwater contamination. Soil particles can be mobilized by air perturbation during SVE, resulting in the differentiation of porous media, which has not been well addressed. This paper developed a numerical method to study the flow pattern and quantify the change of porous media for the first time. Based on the mass equilibrium and Darcy’s law, a two-phase water–air flow model was constructed with integration of saturation, relative permeability, and capillary pressure during SVE. Relationship between porosity and saturation was deduced and coupled with the two-phase flow model for quantifying change of porous media in real time. Results reveal that both porosity and permeability increase sharply in the early stage of SVE then gradually to a quasi-steady state. These increases in vadose zone tapered off with distance from the SVE screen and the steady period occurred later as well. The influence radius of a single SVE well and the change degree in porosity and permeability of media were proportional to the extraction vacuum and the driving coefficient C, which is more sensitive than extraction vacuum according to the simulation results. Knowledge from this modeling exercise provides a useful tool to estimate the change of remediated zone and assess the environmental risk of remedial activities at real-world contamination sites.  相似文献   

Flavonoid constituents of Chorizanthe diffusa with potential cancer chemopreventive activity   总被引：11，自引：0，他引：11  

Chung HS  Chang LC  Lee SK  Shamon LA  van Breemen RB  Mehta RG  Farnsworth NR  Pezzuto JM  Kinghorn AD 《Journal of agricultural and food chemistry》1999,47(1):36-41

An ethyl acetate-soluble extract of Chorizanthe diffusa was found to exhibit significant antioxidant activity, as judged by scavenging stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals and inhibition of 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced free radical formation with cultured HL-60 cells. Bioassay-directed fractionation of this extract using the DPPH antioxidant assay as a monitor led to the isolation of five structurally related flavonoids (1-5), including the novel compound 5,8,3',4',5'-pentahydroxy-3, 7-dimethoxyflavone (1). Isolates 1-5 demonstrated varying degrees of antioxidant or antimutagenic activity. Two of the compounds, 5,7,3', 4'-tetrahydroxy-3-methoxyflavone (2) and quercetin (4), were subsequently found to inhibit carcinogen-induced preneoplastic lesions in a mouse mammary organ culture model. Inhibitory activity of this type is known to correlate with cancer chemopreventive effects in full-term models of tumorigenesis.  相似文献   

Loss of pendimethalin in runoff and leaching from turfgrass land under simulated rainfall   总被引：2，自引：0，他引：2  

Lee YD  Kim HJ  Chung JB  Jeong BR 《Journal of agricultural and food chemistry》2000,48(11):5376-5382

A field study was undertaken to investigate runoff and leaching loss of the herbicide pendimethalin in turfgrass land of loamy sand soil. A series of plots constructed in a golf course fairway were surface-applied with pendimethalin SC formulation at the rate of 2. 25 or 4.50 kg a.i./ha and subjected to simulated rainfall at 2.0 cm/day for 10 consecutive days. Runoff losses of pendimethalin were the highest at the first rainfall and then gradually decreased with time. The first runoff event contained pendimethalin in its highest concentration, and in subsequent runoff samples the concentration decreased exponentially. The ranges of pendimethalin concentration were 80.9-18.2 and 177.4-48.6 microgram/L in the standard and double doses, respectively. Total losses by 20 cm of rainfall for 10 days reached 0.81 and 1.22% of the initial deposits at 2.25 and 4.50 kg a. i./ha, respectively. Pendimethalin concentration in the leachate collected at 30-cm soil depth was quite lower than that in the runoff, and the concentration rapidly decreased from 4.3-4.7 to 0. 2-0.4 microgram/L during the 10 days of rainfall treatment. Soil residue analysis at 45 and 90 days after pendimethalin treatment showed that more than 90% of the residue remained at the top 10 cm of soil depth. Low runoff and leaching confirmed that lateral and downward movement of the herbicide should be limited in turf soil. The half-life of pendimethalin under field conditions was 23-30 days and was not affected by application dose and rainfall treatment, but longer persistence was observed under laboratory conditions. Considering low runoff and leaching, as well as relatively short persistence in soil, it is concluded that little environmental carryover of pendimethalin would be expected in turfgrass land.  相似文献   

A high-resolution radiation hybrid map of the human genome draft sequence     

Olivier M  Aggarwal A  Allen J  Almendras AA  Bajorek ES  Beasley EM  Brady SD  Bushard JM  Bustos VI  Chu A  Chung TR  De Witte A  Denys ME  Dominguez R  Fang NY  Foster BD  Freudenberg RW  Hadley D  Hamilton LR  Jeffrey TJ  Kelly L  Lazzeroni L  Levy MR  Lewis SC  Liu X  Lopez FJ  Louie B  Marquis JP  Martinez RA  Matsuura MK  Misherghi NS  Norton JA  Olshen A  Perkins SM  Perou AJ  Piercy C  Piercy M  Qin F  Reif T  Sheppard K  Shokoohi V  Smick GA  Sun WL  Stewart EA  Fernando J  Tejeda  Tran NM  Trejo T  Vo NT  Yan SC  Zierten DL  Zhao S 《Science (New York, N.Y.)》2001,291(5507):1298-1302

We have constructed a physical map of the human genome by using a panel of 90 whole-genome radiation hybrids (the TNG panel) in conjunction with 40,322 sequence-tagged sites (STSs) derived from random genomic sequences as well as expressed sequences. Of 36,678 STSs on the TNG radiation hybrid map, only 3604 (9.8%) were absent from the unassembled draft sequence of the human genome. Of 20,030 STSs ordered on the TNG map as well as the assembled human genome draft sequence and the Celera assembled human genome sequence, 36% of the STSs had a discrepant order between the working draft sequence and the Celera sequence. The TNG map order was identical to one of the two sequence orders in 60% of these discrepant cases.  相似文献   

Radiation-Induced Breeding in Camelina Sativa     

Chung  Yong Suk  Silva  Renato Rodrigues  Park  Minwoo  Lee  Sanghyeob 《Journal of Crop Science and Biotechnology》2019,22(1):17-20

Journal of Crop Science and Biotechnology - The ionizing radiation methods, including X-rays, gamma rays, and neutrons to create variation is well established and used in major crops. Many...  相似文献   

The grafting of recycled polyol from waste polyurethane foam onto new polyurethane and its impact on shape recovery and water vapor permeation     

Ha Youn Kim  Jae Won Choi  Yong-Chan Chung  Byoung Chul Chun 《Fibers and Polymers》2017,18(5):842-851

Recycled polyols from waste polyurethane (PU) foams were grafted onto PU to improve the properties such as tensile strength, shape recovery, low-temperature flexibility, and water compatibility. The recycled polyol was either purified by column chromatography before grafting or was used directly for grafting. The soft segment melting temperature of PU did not notably increase with the addition of polyol, whereas the glass transition temperature increased with increased polyol content. The tensile strength sharply increased at low polyol content and decreased at high polyol content, while the strain at break did not significantly change with an increase in polyol content. The shape recovery at 10 oC notably improved compared with unmodified PU and remained high after four cyclic tests. Polyol-grafted PU demonstrated better lowtemperature flexibility and reduced the water vapor permeability of PU membranes. Overall, grafting recycled polyol onto PU significantly improved the tensile stress, shape recovery, and low-temperature flexibility of PU.  相似文献   

Development and functional characterization of monoclonal antibodies recognizing chicken lymphocytes with natural killer cell activity.     

K S Chung  H S Lillehoj 《Veterinary immunology and immunopathology》1991,28(3-4):351-363

We have developed two monoclonal antibodies which detect cell surface antigens present on chicken lymphocytes mediating natural killer (NK) cell activity against the avian tumor cell target. The monoclonal antibodies, K-14 and K-108, stained 17 and 6% of splenic lymphocytes, and 11 and 14% of peripheral blood lymphocytes (PBL), respectively, and fewer than 5% of thymic and bursal lymphocytes. Neither of these monoclonal antibodies stained adherent macrophages or the MC29-virus transformed monocytic cell line. Both monoclonal antibodies significantly inhibited NK cell activity in a standard 4 h 51Cr-release cytotoxicity assay using the LSCC-RP9 tumor cell line as target cells at an effector to target ratio of 50:1. Pretreatment of splenocytes with either monoclonal antibody in the presence of rabbit complement (C) resulted in a significant reduction in NK cell activity. However, the monoclonal antibody K-1 which detects normal chicken macrophages did not interfere with NK cell activity. The monoclonal antibody K-108 significantly blocked Fc receptor-mediated rosette formation of sheep red blood cells coated with IgG antibodies (EA) by 56% while the monoclonal antibody K-14 did not show a significant blocking. These results indicate that the monoclonal antibodies K-108 and K-14 identify different epitopes present on the surface of chicken splenic lymphocytes which mediate spontaneous NK cytotoxicity.  相似文献   

杨树水泡型溃疡病菌生理特性的研究   总被引：1，自引：0，他引：1  

钟兆康 《植物病理学报》1982,12(1):45-48

 经试验杨树水泡型溃疡病菌分生孢子的萌芽不超过2小时。以2%葡萄糖溶液处理的孢子萌芽率最高为92.8%。冰箱保存14个月的分生孢子,经24小时的发芽率为73.5。  相似文献