• Journal of Microbiology and Biotechnology
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• v.8 no.6
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• pp.710-713
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• 1998

A material with the same high performance liquid chromatography (HPLC) retention profile as authentic ascorbic acid 2-Ο-$\alpha$-glucoside (AA-2G) was detected in kimchi. This material was identified as AA-2G by testing its susceptibility to $\alpha$-glucosidase hydrolysis, the HPLC profile, and through the elementary analysis. Among several strains of bacteria isolated from fermented kimchi, four strains could produce cydodextrin glucanotransferase (CGTase) which catalyzes the transglucosylation reaction of ascorbic acid. By using starch as the glycosyl donor, AA-2G was produced as the major product through this reaction.

• Applied Biological Chemistry
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• v.47 no.2
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• pp.187-191
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• 2004

For the production of $2-O-{\alpha}-D-glucopyranosyl-L-ascorbic$ acid (ascorbic acid-2-g1ucoside, AA-2G) from ascorbic acid, the usability of spinach seed as the source of ${\alpha}-glucosidase$ having transglucosylation activity was studied. The optimum conditions for the production of AA-2G from ascorbic acid and glucose donor were investigated by using crude extract of Spinachia oleracea L. Woosung, the selected source of enzyme. The production of AA-2G was the highest with 1.053 mM when spinach seeds were grown for 2 days after germination. Maltose was the most effective glucose donor, and the optimum concentration of ascorbic acid and maltose were 175 mM and 225 mM, respectively. The optimum concentration of ${\alpha}-glucosidase$ was 60 units. The most effective buffer was sodium acetate and its optimum concentration was 175 mM. The optimum pH and temperature were 5.0 and $65^{\circ}C$, respectively. Under the optimum condition, 2.14 mM of AA-2G was produced from ascorbic acid after 50 minutes of reaction.

• Applied Biological Chemistry
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• v.43 no.1
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• pp.12-17
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• 2000

For the enzymatic production of $2-O-{\alpha}-D-glucopyranosyl-L-ascorbic$ acid (AA-2G) from ascorbic acid, rice seed was used as the source of ${\alpha}-glucosidase$ having transglucosylation activity. Among six rice varieties, cultivated in Korea, ${\alpha}-glucosidase$ activity of Oryza savita L. cv. Ilpumbyeo was the highest with 125.03 unit/ml and it had maximum specific activity with 8.52 unit/mg protein when rice seeds were grown for 3 days after germination. For the production of AA-2G using crude extract of O. savita L. cv. Ilpumbyeo, maltose was most effective glucose donor. The optimum concentration of maltose and ascorbic acid were 125 mM and 175 mM, respectively. The optimum concentration of ${\alpha}-glucosidase$ was 100 unit. The most effective buffer was 100 mM sodium citrate. The optimum pH and temperature were 5.0 and $60^{\circ}C$, respectively. Under the optimum condition, $108.43\;{\mu}M/unit$ of AA-2G was produced from ascorbic acid after 35 minutes of reaction, which corresponds to 6.2% of conversion ratio based on the amount of ascorbic acid used.

• Preventive Nutrition and Food Science
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• v.3 no.3
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• pp.225-229
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• 1998

Formation of a L-Ascorbic Acid 2-O-$\alpha$-glucoside(AA-2G) is a chemically stable dervative of asocrbate that shows a vitamin C acitivity in vitro as well as in vivo. We studied whether ascorbic acid(AA) and AA-2G are formed in baechu kimchi during fermentation at 4 $^{\circ}C$ or 18$^{\circ}C$. To determine the formation of AA and AA-2G during fermentation of kimchi, wheat flour (as a carbhydrate source) added baechu kimchi (WBK) and control baechu kimchi(CBK) were prepared and fermented at 4 $^{\circ}C$ or 18 $^{\circ}C$. A substance like AA-2G was detected by HPLC from WBK fermented at 18 $^{\circ}C$ for 26 days in fall season and confirmed later to be the AA-2G showing distinctive characteristics of heat stability and resistance to ascrobate oxidase catalase. However, none of the kimchi formed AA-2G when the kimchi were fermented under a different temperature condition such as 4 $^{\circ}C$ instead of 18 $^{\circ}C$ or a different season such as summer instead of fall even if they were fermented at 18 $^{\circ}C$. The pH of kimchi was decreased rapidly during the first 3 days. and then decreased slowly after 4 days when the kimchi were fermented at 18 $^{\circ}C$. However, there were slight changes of pH in both CBK and WBK feremented at 4$^{\circ}C$ for 30 $^{\circ}C$ days. Therefore, the AA-2G -forming activity in kimchi seems to be correlated with the formentation temperature, the microorganisms involved in kimchi fermentation and a suitable glycosyl donor for AA as provided by wheat flour in this study.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.262-262
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• 2006

Biodegradable and amphiphilic di-block and tri-block copolymers, prepared with monomethoxy poly ethylene glycol (MPEG) and ${\varepsilon}-caprolactone\;({\varepsilon}-CL)$, were used for the application of W1/O/W2 multi- emulsion capsules. The effects of topology and the ratio of hydrophilic moiety of PCL-based polymers on the encapsulation efficiency of the $W_{1}/O/W_{2}$ multi-emulsion capsules containing Ascorbic Acid-2-Glucoside (AA-2-G) were investigated. The ratio of PEG and PCL was 1:0.5, 1:0.75, 1:1, and 1:1.25. PEG-PCL block copolymers were added to the first step of the preparation of $W_{1}/O$ emulsions. The dispersion stability, the particle size, the morphology of the $W_{1}/O/W_{2}$ multi-emulsion capsules were observed using an on-line turbidity meter, dynamic light scattering (DLS), a confocal microscopy (with FITC) and an optical microscopy. Biodegradable behavior of the PEG-PCL block copolymers and release behavior of AA-2-G were also observed by Gel Permeation Chromatography (GPC) and High Performance Liquid Chromatography (HPLC).

• Archives of Pharmacal Research
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• v.25 no.5
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• pp.625-627
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• 2002

From the leaves of Brassica juncea, an radical scavenging isorhamnetin 7-Ο-glucoside on peroxynitrite and 1,1-diphenyl-2-picrylhydrazyl (DPPH) was isolated and characterized based on the spectroscopic evidence. The compound showed the peroxynitrite and DPPH scavenging activities with $IC_{50}$ values of 2.07$\pm$0.17 and 13.3 $\mu$M, respectively. Penicillamine and L-ascorbic acid as positive control exhibited radical scavenging activities with $IC_{50}$ values of 3.17$\pm$0.39 and 12.78 $\mu$M, respectively.

• Archives of Pharmacal Research
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• v.26 no.1
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• pp.24-27
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• 2003

A furanofuranoid lignan glycoside, with radical scavenging on peroxynitrite, total reactive oxygen species (ROS) and 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical, was isolated from the rhizome of Salvia miltiorrhiza and characterized as (+)-1-hydroxypinoresinol-1-Ο-$\beta$-D-glucoside based on spectroscopic evidence. The compound exhibited peroxynitrite, total ROS and DPPH radical scavenging activities with $IC_{50}$ values of 3.23$\pm$0.04, 2.26$\pm$0.07 and 32.3$\pm$0.13 $\mu$M, respectively. Penicillamine, Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid) and L-ascorbic acid, acting as positive controls, showed radical scavenging activities with $IC_{50}$ values of 6.72$\pm$0.25, 1.43$\pm$0.04 and 11.4$\pm$0.07 $\mu$M, respectively.

• Archives of Pharmacal Research
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• v.25 no.3
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• pp.300-305
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• 2002

The EtOAc and n-BuOH soluble fractions from the aerial part of Setaria viridis showed a strong free radical scavenging activity. Six major compounds were isolated from these fractions. They were identified by spectral data as tricin (1), p-hydroxycinnamic acid (2), vitexin 2"-Ο-xyloside (3), orientin 2"-Ο-xyloside (4), $tricin-7-Ο-{\beta}-D-glucoside$ (5) and vitexin 2"-Ο-glucoside (6). Among these compounds, 4 and 5 exhibited strong free radical scavenging activities on 1, 1-diphenyl-2-picrylhydrazyl (DPPH). We further studied the effects of these isolated compounds on the lipid peroxidation in rat liver microsomes induced by non-enzymatic method. As expected, 4 and 5 exhibited significant inhibition on $ascorbic/Fe^{2-}$ induced lipid peroxidation in rat liver microsomes.ver microsomes.

• Korean Journal of Food Science and Technology
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• v.27 no.1
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• pp.124-128
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• 1995

The present study was conducted to elucidate nitrite scavenger derived from seeds of Cassia tora L. Methanolic extract of Cassia tora L was refractionated into ethyl ether, chloroform, ethyl acetate and water farction, and nitrite scavenging abilities of these fractions were investigated. Among these fractions, ethyl acetate fraction had the strongest nitrite scavenging ability(97%/2 mg). Therefore, to further investigate nitrite scavenger, ethyl acetate fraction was fractionated by silica gel column chromatography with a chloroform-methanol($10:0{\sim}0:10$) and then compound A and B were isolated. Compound A had a stronger nitrite-scavenging effect than compound B. Therefore the further separation of compound A was carried out by HPLC(32% acetonitrile. 1 ml/min) using ${\mu}Bondapak$C18 column$(3.9{\times}300 mm)$ and finally compound A-1 was obtained from compound A. Compound A-1 had by far nitrite-scavenging ability as compared with that of ascorbic acid. Compound A-1 was identified as $nor-rubrofusarin-6-{\beta}-mono-D-glucoside$ from the profiles of UV, IR and $^1H-NMR$.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.1
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• pp.13-18
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• 2006

The antioxidant activity of the extract of Erigeron annuus was assessed by means of two different in vitro tests: bleaching of the stable 1,1-diphenyl-2-picrylhydrazyl radical (DPPH test) and the scavenging of authentic peroxynitrite in company with peroxynitrite generation from 3-morpholinosydnonimine (SIN-1). In both tests, the 85% aq. MeOH and n-BuOH soluble fractions of the crude extract showed a significant scavenging effect on peroxynitrite and DPPH radical in comparison to L-ascorbic acid. And bioassay-guided fractionation of the n-BuOH soluble fraction led to the isolation of three compounds: Apigenin (1), quercetin-3-O-glucoside (2), and caffeic acid (3). The structures of the isolated compounds were elucidated on the basis of their spectroscopic data and their antioxidant activities were measured by determining their capacity to scavenge peroxynitrite and the DPPH radical.