• Korean Journal of Food Science and Technology
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• v.36 no.2
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• pp.311-316
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• 2004

Antioxidant effects of Rosa davurica Pall extract on copper-mediated LDL oxidative modification were investigated. Oxidation products of LDL were determined based on TBA value, formation of conjugate diene, and apolipoprotein carbonyl value. As revealed through TBA values, ethyl acetate and butanol fractions of R. davurica Pall root showed strong antioxidant effect, with 85.3 and 93.2% inhibitions at $30\;{\mu}g/mL$ each, respectively. Ethyl acetate and butanol fractions at $30\;{\mu}g/mL$ inhibited LDL oxidation up to 8 hr. Conjugate diene formation by lipid oxidation with $Cu^{2+}$ addition in ethyl acetate and butanol fractions decreased 2.2-and 5.6-fold, respectively, compared to control. Carbonyl value decreased in the presence of butanol and ethyl acetate fractions. Methanol and ethyl acetate extracts of R. davurica Pall root showed higher absorbancy at 285 nm. Ethanol extract of R. davurica Pall root and stem contained 10.6 g/100 g total phenolic compounds. Results reveal phenolic compound as major biological component in R. davurica Pall extracts. Ethyl acetate and butanol fraction showed strongest antioxidant effect on LDL oxidation.

• Journal of agriculture & life science
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• v.44 no.3
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• pp.69-78
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• 2010

To get basic data for the utilization of Pinkpop Borisu fruit and leaf as a raw material in functional food, antioxidative activities were investigated. The radical scavenging activity of various solvent fraction from fruit and leaf against the DPPH and ABTS radicals increased with the increasing amount of various solvent fractions and butanol fraction of leaf showed the highest DPPH radical scavenging activities. Among the various solvent fractions from fruit and leaf of Pinkpop Borisu, butanol fraction of leaf showed the strongest scavenging effect on ABTS radicals. Reducing power and ferric reducing/antioxidant power (FRAP) of the various solvent fractions from fruit and leaf increased with the increasing concentration of fractions and butanol fraction of leaf showed the highest reducing power. The butanol fraction of fruit and leaf showed strong antioxidative activity on linoleic acid system. Total phenolics contents of butanol fraction from fruit and leaf were 106.34 and 252.46 mg/g, respectively. The antioxidative activities of the butanol fraction from fruit and leaf are attributed to phenolic compounds. The present results suggest that butanol fraction of Pinkpop Borisu leaf would have the protective potential from oxidative stress induced by free radicals.

• Journal of Practical Agriculture & Fisheries Research
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• v.21 no.1
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• pp.89-98
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• 2019

The aim of this study was to evaluate the change of phenolic compounds after bordeaux mixture treatment on Cheorwon onion. Onion is a perennial plant belonging to the lily family. It is native to Persia of Southwest Asia. It is cultivated much in the temperate regions of the world. Onion is a good name for the 'Okchong' to drop blood cholesterol and cardiovascular blood flow to increase the prevention of adult diseases. Cheorwon area is inland, but it has high continental climate due to its high altitude. After the treatment with bordeaux mixture, the weight, width and plant height of the onion were affected to some extent. In the phenolic compounds, caffeic acid, ferulic acid, rutin, and kaempferol except benzoic acid, p-coumaric acid and quercetin were similar to or less than the control. Therefore, it was concluded that the treatment with bordeaux mixture had some effect on onion growth and phenolic compound contents.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.8
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• pp.1206-1211
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• 2015

Grape juice is consumed worldwide and studied due to the high antioxidant activities and contents. The color of grape juice is due to the presence of phenolic compounds such as anthocyanins. Therefore, color values can be an indicator of antioxidant capacities of grape juice. However, the correlation between color values and antioxidant activities in grape juice has not been well studied. In this study, the physicochemical characteristics and correlation between color values and antioxidant capacities of Korean red grape juices (five commercial juices from market and two juices prepared in the laboratory) were investigated to estimate antioxidant capacities. Antioxidant capacities were determined by 1,1-diphenlyl-2-picrylhydrazyl radical scavenging assay, ferric ion reducing antioxidant power assay, and oxygen radical absorbance capacity assay. Total phenolic contents, total flavonoid contents, and total anthocyanin contents, including five kinds of polyphenolic compounds, were examined by high performance liquid chromatography (HPLC). The results for physicochemical properties showed similar values, except titratable acidity. The color hue values of the prepared juices were higher than those of commercial juices, which was in contrast to the lower color intensity values (P<0.05). The Hunter L, a, and b values showed almost no difference between commercial and prepared juices. The antioxidant activities and total phenolic contents of commercial juices were higher than those of prepared ones. Gallic acid, catechin, and quercetin were confirmed by HPLC in all samples. The total phenolic and total flavonoid contents showed positive correlation with antioxidant activities. In addition, antioxidant activities and contents correlated with color values. Thus, estimation of antioxidant capacity could be feasible through the spectrophotometric measurement of color values.

• Korean Journal of Food Science and Technology
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• v.44 no.6
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• pp.763-771
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• 2012

In this study, total antioxidant properties of extracts from different parts of Lespedeza bicolor were determined using techniques of measuring 1,1-diphenyl-2-picryl hydrazyl/2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)-radical scavenging activity and total phenolic contents. The total antioxidant activities of leaf, stem and root extracts from various solvents (water, 50, 70, 100% ethanol, and hot-water) indicated that 50 and 70% ethanol extracts have high radical scavenging activities and phenolic contents. A systematic approach was used to determine the total antioxidant activity of different solvent fractions of the Lespedeza bicolor extracts, partitioning with chloroform, ethyl acetate, n-butanol, and water, and the ethyl acetate fraction was found to have the strongest antioxidant activity. Antioxidant assay-guided isolation was carried out to isolate potential antioxidant compounds. The ethyl acetate fraction of the leaf extract was subjected to silica gel, LH-20 and RP-18 column chromatography successively, and afforded compound 1, which was identified as eriodictyol by NMR and MS analysis, after which its antioxidant activity was determined.

• Horticultural Science & Technology
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• v.33 no.1
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• pp.55-60
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• 2015

Skin blackening is a serious postharvest disorder occurring in 'Fuyu' persimmon fruits (Diospyros kaki, 'Fuyu'). Phenolic content, polyphenol oxidase (PPO) and peroxidase (POD) activity, and lipid saturation were investigated in skin tissue of 'Fuyu' fruits. The phenolic compounds were accumulated unevenly on fruit skin depending on sunlight exposure, i.e., the most accumulation on sunny side and the least on the opposite, shaded side. The fruits harvested from shaded branches inside the canopy showed relatively even distribution of phenolic compounds in the skin. The activity distribution of PPO and POD were also uneven but only in fruits suffering f rom skin b lackening disorder, w ith the h ighest and the lowest a ctivity of PPO and P OD, respectively, in the blackened area of the fruit. When the sunny, southern sides of fruits were marked at harvesting time and fruits were stored at low temperature, a round black spot, as a symptom of skin blackening disorder, developed during storage exactly on the marked region. In addition, the sunny side of fruit showed higher lipid saturation, thus indicating adaptation to high temperature caused by the sunlight. These results suggest that the skin blackening disorder of 'Fuyu' fruits can be considered as a kind of chilling injury symptom that develops on the high-temperature-acclimated skin tissue of sunlight-exposed fruits when they are later exposed to low temperature.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.2
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• pp.274-279
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• 2000

Effect of potato polyphenolic compound on the concentrations of serum and liver lipids, serum glucose, and urine protein was investigated in Sprague Dawley rats by feeding a diet containing 0.5% of cholesterol for 2 weeks. Polyphenolic compound extracted from potato (Solanum tuberosum variety Dejima) was supplemented at a 0.5% level in the basal diet or the cholesterol diet. The supplementation of potato polyphenolic compounds decreased slightly the concentrations of total cholesterol and VLDL+LDL-cholesterol in serum, and atherosclerotic index in rats fed the cholesterol diet, while those measurements were not altered by the supplementation of potato polyphenolic compounds in rats fed the basal diet. In the rats fed the basal diet or the cholesterol diet containing potato polyphenolic compounds, urine protein increased by 12% and 27% at 1st week, respectively, but this change was not seen at 2nd week. The concentration of serum glucose, however, was not significantly different in the dietary groups.

• Microbiology and Biotechnology Letters
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• v.32 no.1
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• pp.37-46
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• 2004

The analysis of enzymes associated with metabolism of phenolics by Stenotrophomonas maltophilia LK-24 was conducted. To identify metabolites of phenol and phenol compound, we investigated enzymes of S. maltophilia LK-24 associated with degradation of phenolics. We found that phenol hydrolase, catechol-2.3-dioxygenase, 2-hydroxymuconic semialdehyde dehydrogenase, 2-hydroxymuconic semialdehyde hydroxylase and acetaldehyde dehydrogenase were activated. The results showed that phenolics were gone through the meta-pathway ring cleavage. The results will contribute greatly to understand metabolic pathways of phenol and it is possible to make some assessment of the feasibility of using S. maltophilia LK-24 for the treatments of phenolic-contaminated waste streams.

• 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.

• Journal of the Korean Society of Food Culture
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• v.20 no.5
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• pp.603-607
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• 2005

Fourteen phenolic compounds(benzoic acid, p-hydroxybenzoic acid, protocatechuic acid, vanillic acid, syringic acid, gallic acid, caffeic acid, ferulic acid, (+)-catechin, quercetin, rutin, catechol, chlorogenic acid and L-ascorbic acid) were examined for their effects on the anticarigenic activity. Among tested samples, catechol was significantly inhibited the S. mutans, exhibiting an clear zone 18.5-19.5mm by 10 mg/disc level. The minimal inhibition concentration(MIC) of the phenolic compounds for Streptococcus mutans, M1 and M2 strain were determined as 2,000 ppm, whereas catechol was 1,000 ppm. The activity of glucosyltransferase(GTase) was significantly inhibited by catechol, at 10 ppm(58.7%), 50 ppm(60.7%) and 100 ppm(88.4%) and 500 ppm(89.6%), respectively. Among them, catechol showed most significant anticariogenic activity as well as inhibition of GTase activity.