• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.9
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• pp.1385-1390
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• 2016

Gallic acid is a representative hydroxybenzoic acid and is found in free form in several plants and in various esterified forms as a part of hydolyzable tannins. Convenient enzymatic transformation of trihydroxylated gallic acid with polyphenol oxidase originating from pear was evaluated to investigate whether polyphenol oxidase can be used as a valuable compound to improve the biological activity of gallic acid. Enzymatic oxidation processing of gallic acid using polyphenol oxidase was carried out for five different reaction times. The antioxidant effects of transformed gallic acid for different reaction times were evaluated via radical scavenging assays using 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radicals. In addition, the anti-diabetic property of the transformed gallic acid was measured based on ${\alpha}$-glucosidase. Gallic acid reacted for 5 h showed significantly higher antioxidant and ${\alpha}$-glucosidase inhibitory activities compared to the tested positive control substances. Biotransformation of simple gallic acid induced by polyphenol oxidase might be responsible for enhancing the biological activity of gallic acid.

• Korean Journal of Organic Agriculture
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• v.21 no.4
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• pp.737-752
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• 2013

This study was conducted to evaluate the allelopathic effect of aqueous extract of Ganghwa domestic mugwort (Artemisia spp.) on vegetables and its related allelo-chemicals. When the receptor vegetables, such as Chinese cabbage, lettuce, and red radish, were treated with aqueous extract obtained from Sajabalssuk (A. $sp^*I$), Ssajuarissuk (A. $sp^*II$) or Ssajarissuk (A. $sp^*III$), their germination rate, leaf number, plant height, and root length were restricted with increasing concentration of aqueous extract. Allelopathic effect was the highest in radish, than lettuce and Chinese cabbage in order. The growth of topplant were more inhibited then root growth observing in restriction of plant height, root length, and chlorophyll contents. The plant height, the root length of red radish were 53.3 and 61.2% and their fresh weights were 19.8 and 26.4% compared to those of controls, respectively. A. $sp^*III$ showed the highest allelopathic effect among the donor plants. In HPLC analysis, 7 phenol compounds were identified in A. $sp^*I$ and A. $sp^*II$, and, in A. $sp^*III$, and hydroxybenzoic acid and phenylacetic acid were further identified as allelochemicals. It is considered that their plant growths were variously inhibited by the amounts and types of allelochemicals in aqueous extracts. To increase the productivity of farm land after cultivation of mugwort, these results can be useful to select the following field crops.

• Korean Journal of Food Science and Technology
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• v.43 no.5
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• pp.558-563
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• 2011

In the course of our investigation for chemical constituents in the ethyl acetate layer of Korean black raspberry wine, five compounds were isolated and purified by silica gel column chromatography and high-performance liquid chromatography. The isolated compounds were identified as ethyl succinate (1), vanillic acid (2), ethyl 3,4-dihydroxybenzoate (3), furan-2-ol (4), and 4-(4-hydroxyphenyl)butan-2(S)-ol (5) based on the spectroscopic data of electrospray ionization tandem mass spectrometry and nuclear magnetic resonance. The presence of 2 in Korean black raspberry has previously reported. However, 1 and 3-5 in Korean black raspberry and its wine were isolated for the first time.

• The Korean Journal of Food And Nutrition
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• v.24 no.3
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• pp.291-294
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• 2011

A lipase inhibitor from Desmodium oxyphyllum DC. was purified by methanol extraction, systematic solvent extraction, silica gel column chromatography, $C_{18}$ solid phase extraction chromatography and RP-HPLC. We obtained the purified lipase inhibitor with 182 ng($IC_{50}$) of lipase inhibitory activity for a 0.06% yield. Its molecular weight was estimated to be 655.37 Da from an instrumental analysis of MALDI-TOF-MS and it was identified copper-3,5-dibromo-2-hydroxybenzoic acid ($C_{14}H_8Br_4CuO_6$) by $^1H$, $^{13}C$ NMR analysis.

• Korean Journal of Pharmacognosy
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• v.38 no.3 s.150
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• pp.263-269
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• 2007

Nelumbo nucifera (Nymphaeaceae) has been widely used in a traditional oriental medicine to treat bleeding, fever, diarrhea, hemorrhoid, sunstroke, dysentery and dizziness. The leaves of this plant were refluxed with methanol, and then fractionated with organic solvents to screen the antioxidant activity using DPPH radical. Ethyl acetate and n-butanol fractions showed good DPPH radical scavenging effects and were carried out column chromatographies to isolate nine compounds. Their chemical structures were characterized as p-hydroxybenzoic acid (1), uracil (2), luteolin (3), quercetin $3-O-{\beta}-D-glucopyranoside$ (4), $rhamnetin 3-O-{\beta}-D-glucopyranoside$ (5), $isorhamnetin 3-O-{\beta}-D-glucopyranoside$ (6), $quercetin 3-O-{\beta}-D-glucuropyranoside$ (7), $quercetin 3-O-{\beta}β-D-xylofuranosyl(1{\rightarrow}2)-{\beta}-D-galactopyranoside$ (8), and adenine (9) by comparison NMR spectral data and with those in references. Compounds 1, 2, 5 and 9 were firstly isolated from this plant. Compounds 1, 3 and 4 showed potent DPPH radical scavenging activity. Especially, compound 3, luteolin showed the higher effect than ascorbic acid used as a positive control.

• Korean Journal of Pharmacognosy
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• v.39 no.3
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• pp.233-236
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• 2008

In order to find the antioxidative components, fractionation of Cyperus amuricus (Cyperaceae) methanol extract was performed by measuring the DPPH (1,1-diphenyl-2-picrylhydrazyl) scavenging effect. Three compounds, 3,4-dimethoxy benzoic acid (1), 4-hydroxybenzoic acid (2), and piceatannol (3) were isolated from the active ethylacetate soluble fraction of C. amuricus through repeated silica gel and Sephadex LH-20 column chromatography. Among them, compound 3 showed the significant antioxidative effect on DPPH free radical scavenging test. These compounds are reported for the first time from this plant.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.3
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• pp.263-269
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• 1992

These studies was conducted to investigate the influence of ALLELOPATHIC effects of upland weeds on crops and soil microorganisms. The aqueous extract of weed residues were used to identify physiological controll of plant and microorganisms. The results obtained are as follows : 1. The aqueous extract of weeds controlled germination and growth of plant, especially the 5%-extract of Potulaca oleracea suppressed the growth of soybean about 8~12%. 2. The 5%-extract of Potulaca oleracea inhibited effect of phytosynthesis of soybean about 60%. 3. The move the concetration of phenolic compounds in soil, the less a number of actinomycetes and bacteria. 4. The number of soil microorganism(fusarium oxysporum spp.) were decresed as to the concentration of vanillic acid was increased.

• Food Science and Preservation
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• v.18 no.6
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• pp.817-823
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• 2011

Angelicae gigas Nakai has been used as a traditional medicine as well as an edible vegetable in South Korea. In this study, the total phenolic and flavonoid content and antioxidants of A. gigas Nakai leaves were examined in vitro via hydroxyl-radical-scavenging activity, reducing power activity, metal chelating assay, and DPPH-free -radical-scavenging assay. Among all the extracts from A. gigas Nakai leaves, the ethanol extract showed the strongest effects in all of the assays. The $EC_{50}$ values for the DPPH-radical-scavenging activities of ethanol, methanol, and water extracts were 31.47, 42.14, and $58.47{\mu}g/mL$, respectively. Among the extracts from A. gigas Kakai leaves, the ethanol extract had the highest levels of total phenolics ($7.84{\pm}1.46$ mg TAN/g) and total flavonoids ($4.23{\pm}0.03$ mg QE/g), which correlated strongly with the individual phenolic-compound (p-hydroxybenzoic acid, vanillin, and trans-ferulic acid) contents. The ethanol extract also showed stronger antioxidant activity than tocopherol in hydroxyl- radical-scavenging activity assay. These results indicate that the ethanol extract of A. gigas Kakai leaves possesses significant antioxidant properties, which suggests its great potential as a functional-food ingredient in the food industry.

• Bulletin of the Korean Chemical Society
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• v.34 no.4
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• pp.1131-1136
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• 2013

Parabens, the esters of p-hydroxybenzoic acid, have been widely used as antimicrobial preservatives in cosmetic products, drugs, and processed foods and beverages. However, some parabens have been shown to have weak estrogenic effects through in vivo and in vitro studies. Because such widespread use has raised concerns about the potential human health risks associated with exposure to parabens, we developed a simultaneous analytical method to quantify 4 parabens (methyl, ethyl, propyl, and butyl) in human urine, by using solid-phase extraction and high-performance liquid chromatography coupled with triple quadrupole mass spectrometry. This method showed good specificity, linearity ($R^2$ > 0.999), accuracy (92.2-112.4%), precision (0.9-9.6%, CV), and recovery (95.7-102.0%). The LOQs for the 4 parabens were 1.0, 0.5, 0.2, and 0.5 ng/mL, respectively. This method could be used for quick and accurate analysis of a large number of human samples in epidemiological studies to assess the prevalence of human exposure to parabens.

• Korean Journal of Food Science and Technology
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• v.51 no.1
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• pp.90-96
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• 2019

Unripe astringent persimmon (Diospyros kaki Thunb. cv. Cheongdo-Bansi) is a by-product produced when thinning out the superfluous fruit of persimmon. We investigated whether unripe astringent persimmon has antioxidative and anti-inflammatory effects. Unripe astringent persimmon extract was fractionated sequentially in n-hexane, chloroform, ethyl acetate, n-butanol, and water. The ethyl acetate fraction had the highest total phenolic content, total flavonoid content, and antioxidant capacity compared to those of the other fractions. Pretreatment of lipopolysaccharide-stimulated RAW 264.7 macrophages with the ethyl acetate fraction reduced nitric oxide, interleukin-6, and intracellular oxidative stress in a dose-dependent manner. Ultra-high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry analysis revealed gallic acid, protocatechuic acid, 4-hydroxybenzoic acid, quercetin-3-O-glucoside, quercetin, and p-coumaric acid as the phenolic compounds of the ethyl acetate fraction. Collectively, these findings suggest that unripe astringent persimmon is a source of functional materials that can promote antioxidative and anti-inflammatory effects.