• Natural Product Sciences
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• v.24 no.2
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• pp.119-124
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• 2018

Two triterpenoids, arjunolic acid (1), belleric acid (2), five phenylethanoids, martynoside (3), orobanchoside (4), 3,4-dihydroxyphenethylalcohol-6-O-caffeoyl-${\beta}$-$\text\tiny{D}$-glucoside (5), leucosceptoside B (6), lunariifolioside (7), four phenolic acids, ferulic acid (8), syringic acid (9), vanillic acid (10), 4-hydroxybenzoic acid (11), and one lignan, (+)-syringaresinol-${\beta}$-$\text\tiny{D}$-glucoside (12), were isolated from the roots of P. umbrosa. All isolated compounds were explored for their antioxidant potential in the DPPH and ABTS assays. In DPPH assay, compound 5 showed high antioxidant capacity. Compounds 3, 4, 6, and 7 displayed considerable antioxidant activities. In addition, compounds 5-7 exhibited potential antioxidant capacities in the ABTS assay.

• Preventive Nutrition and Food Science
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• v.19 no.3
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• pp.204-212
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• 2014

The bioactive compounds and antioxidant activity of aronia leaves at different stages of maturity were identified and evaluated. Young and old leaves were approximately 2 months of age and 4 months of age, respectively. The young leaves contained more polyphenols and flavonoids than the old leaves. Three phenolic compounds (i.e., chlorogenic acid, p-coumaric acid, and rutin) were detected by HPLC. Antioxidant activity was measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical, and superoxide anion radical scavenging assays. The reducing power of aronia leaf extracts increased in a concentration-dependent manner ($0{\sim}100{\mu}g/mL$). The antioxidant activity of the 80% ethanol extract was greater than that of distilled water extract. The high phenolic compound content indicated that these compounds contribute to antioxidant activity. The overall results indicate that aronia leaves contain bioactive compounds, and that younger aronia leaves may be more favorable for extracting antioxidative ingredients because they contain more polyphenols.

• Food Science and Biotechnology
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• v.16 no.2
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• pp.187-192
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• 2007

The objectives of this study were to examine changes in the color and antioxidant compounds of paprika powder under various conditions, as well as to establish the suitable conditions for drying and storage. Paprika was dried using the following methods: freeze-drying, vacuum drying, far infrared-ray drying, and hot-air drying. Measurements of the moisture content, color pigments, and antioxidant compounds (total carotenoids, capsanthin, ascorbic acid, and total polyphenols) were completed during 120 days of storage at 4 and $30^{\circ}C$. We found that drying methods, storage temperatures, and packaging materials affected the American Spice Trade Association (ASTA) and Hunter color values, as well as the antioxidant content of paprika powder. There was a high correlation (r=0.87, p<0.01) between the ASTA color and the $a^*/b^*$ value. The loss of red color was closely related to the reduction of moisture content (r=0.81, p<0.01) during storage. Drying paprika with a low temperature in the absence of air resulted in better retention of the carotenoids and ascorbic acid. Also, as the retention of the carotenoids and ascorbic acid increased, the stability of the red pigment increased. Freeze-drying was found to be the most suitable drying method for the stability of the antioxidant compounds and red pigment.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.7
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• pp.815-819
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• 2008

The colored rice, particularly black rice, has been well characterized to possess antioxidant properties. Rice bran, a by-product of the rice milling process, contains high levels of several phytochemicals which have antioxidant activities as well as health-beneficial properties. The purposes of this study were to evaluate the antioxidant compounds and antioxidant activities of the methanolic extracts from milling fractions and whole grain of two black rice cultivars. Whole black rice of the two cultivars were milled into rice bran and endosperm using the gradual milling system. These were evaluated for antioxidative activities by DPPH and ABTS radical scavenging activities. To determine the antioxidant compounds in the methanolic extract from the milling fractions, the content of polyphenolics, flavonoids, anthocycanins and ${\gamma}$-oryzanol were measured by spectrophotometric methods and vitamin E analysis was carried out by HPLC. The yield of whole black rice, rice bran, and endosperm were 3.1, 15.3, and 0.9% for Heugjinjubyeo and 2.7, 15.5, and 1.1% for Heugkwangbyeo, respectively. The methanolic extracts from rice bran showed generally higher antioxidant activities than the extracts from whole grain and endosperm. In addition, antioxidant compounds distributed much higher contents in rice bran extract than in the extracts from whole grain and endosperm. A significant correlation was also noted between free radical scavenging activity and polyphenolic compounds. The results of this study show that notable antioxidant activity in black rice bran are considered to have significant health benefits.

• Korean Journal of Plant Resources
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• v.22 no.4
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• pp.323-329
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• 2009

In order to find out superior corn line which has a strong antioxidant activity in the corn silk, antioxidant compounds and antioxidant activity were measured from various inbred and F1 lines. As a result, the contents of phenolic and flavonoid compounds range from 532 mg/100 g to 3,274 mg/100 g and from 980 mg/100 g to 2,420 mg/100 g respectively. Absorbance at 517 nm for contents of anthocyanins ranges from 0.05 to 0.76. Correlation coefficients between antioxidant compounds and various antioxidant assays such as DPPH, ABTS and FRAP were analyzed. Correlation coefficients between antioxidant activity and phenolic compounds and anthocyanin were significantly high in ABTS and FRAP assays. Considering acidic extraction condition and intervention between anthocyanins and DPPH solution, ABTS assay and FRAP assay are more suitable methods to evaluate antioxidant activity of corn silks. Especially, ABTS assay is thought to be the best method among three assays because the antioxidant activity in ABTS assay showed high correlation with phenol, flavonoid and anthocyanin compounds respectively. Among the samples, S15 which showed the highest contents of total phenolic compounds and the most potent antioxidant activity in ABTS and FRAP assay will be a good source for functional material.

• Biomolecules & Therapeutics
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• v.18 no.2
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• pp.191-196
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• 2010

In the course of screening for antioxidant compounds by measuring the radical scavenging effect on 1,1-diphenyl- 2-picrylhydrazyl (DPPH), a total extract of the twigs of Stewartia koreana (Theaceae) was found to show potent antioxidant activity. Subsequent activity-guided fractionation of the methanolic extract led to the isolation of six phenolic compounds, ampelopsin (1), catechin (2), proanthocyanidin-A2 (3), fraxin (4), (2R, 3R)-taxifolin-3-${\beta}$-D-glucopyranoside (5), and (2S, 3S)-taxifolin-3-${\beta}$-D-glucopyranoside (6), as active principles. Their structures were elucidated by spectroscopic studies. Compounds 1-6 were isolated for the first time from this plant. Among them, three compounds 1-3 showed the significant antioxidative effects on DPPH, and riboflavin originated superoxide quenching activity. In riboflavin-nitrobluetetrazolium (NBT)-light system, compound 1 showed better superoxide quenching activity than vitamin C.

• Natural Product Sciences
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• v.13 no.2
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• pp.140-143
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• 2007

Investigation of the chloroform soluble fraction of the red alga Liagora farinosa, collected from Hurghada at the Red Sea resulted in the isolation of three compounds; a nucleoside (thymidine) and two glycosides (methyl-${\beta}$-D-xylopyranoside and glycerol-2-${\alpha}$-D-glucopyranoside). The structures of the isolated compounds were established on the basis of different spectroscopic techniques as well as comparison with the previously published data. This is the first report for the isolation of the three compounds fron red algae; moreover, the compounds were examined for their antioxidant activity and showed variable activity.

• Korean journal of food and cookery science
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• v.24 no.3
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• pp.358-366
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• 2008

The antioxidant properties of red ginseng extracts prepared under different extraction conditions were evaluated by a variety of antioxidant assays, including $DPPH^{\cdot}$ radical scavenging, $ABTS^{+\cdot}$ radical scavenging, superoxide anion scavenging, nitrite scavenging and reducing power activities. The contents of total phenolic compounds and flavonoids were also determined. The various antioxidant activities were compared to positive controls such as Trolox, tannic acid and ascorbic acid. The antioxidant activities of all of the extracts were shown to be the highest in the ethanol extract. The antioxidant activities of the red ginseng powder were the lowest among the samples. The amounts of total phenolic compounds and flavonoids were at a maximum in the ethanol extract. Correlation analysis demonstrated the existence of a linear relationship between free radical scavenging activities and the phenolic compounds contents of extracts. The antioxidant activity of yogurt was increased as the result of the addition of red ginseng extract. The quality characteristics of the yogurt to which red ginseng extract was added were similar to those of yogurt without red ginseng extract. The overall sensory score and color of yogurt made from 0.5% red ginseng was the best of the tested yogurts. In accordance with the antioxidant activity and quality characteristics, the optimal concentration of red ginseng extract was approximately 0.5%.

• Korean Journal of Pharmacognosy
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• v.38 no.2 s.149
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• pp.164-169
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• 2007

ln our continued search for biologically active compounds from traditional medicine, we found that ethyl acetate fraction from Inonotus obliquus showed potent antioxidant activities on three different cell-free bioassay systems. Bioassay-directed chromatographic fractionation of the ethyl acetate fraction from Inonotus obliquus afforded four phenolic compounds, 4-(3,4-dihydroxyphenyl)-(E)-3-buten-2-one (1) , 3,4-dihydroxybenzaldehyde (2), protocatechuic acid (3) and caffeic acid (4) along with three sterols such as lanosterol (5), ergosterol peroxide (6) and 9,11-dehydroergosterol peroxide (7). Among isolates, phenolic compounds (1-4) were assessed for antioxidant activities. Almost phenolic compounds showed potent DPPH and superoxide anion radicals scavenging and lipid peroxidation inhibitory activities indicating that these phenolic compounds contribute to the antioxidative activities of I. obliquus. Compounds 2-3 and 7 were isolated for the first time from this plant.

• Korean Journal of Medicinal Crop Science
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• v.24 no.5
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• pp.351-359
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• 2016

Background: We investigated the optimal aqueous extraction conditions for recovery of high yields of total phenolic compounds from roots of Arctium lappa L. (burdock, Asteraceae), and we compared their antioxidant capacity. Methods and Results: The antioxidant activity of the extracts was tested using 2,2-diphenyl-1-picrylhydrazyl, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)-diammonium salt, and oxygen radical absorbance capacity assays. In addition, the major phenolic compounds present in the extracts were determined by high performance liquid chromatography analysis. Our results suggest that the roasted burdock $100^{\circ}C$, 15 min extract exhibited the strongest radical scavenging activity and possessed the highest concentration of phenolic compounds. The polyphenol content of both dried burdock and roasted burdock significantly increased with increase in the extraction temperature and time. Conclusions: These results indicated a relationship between phenolic compound levels in burdock and their free radical scavenging activities. This suggests that phenolic compounds significantly increase the antioxidant potential of burdock extracts.