• Korean Journal of Plant Resources
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• v.21 no.6
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• pp.413-419
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• 2008

Phenolics level, total flavonoid content, and antioxidant were determined from the methanol extracts of the eight medicinal plants using roots. Total phenolics were found as the highest levels in the methanol extracts of Arctium lappa, and followed by Youngia sonchifolia and Cirsium japonicum. Total amount of the each phenol compounds were detected in C. japonicum extracts ($319.2\;mg\;kg^{-1}$) as the greatest component, and followed by A. lappa ($96.3\;mg\;kg^{-1}$) and Y. sonchifolia ($22.9\;mg\;kg^{-1}$). Total flavonoid content showed the highest amount in methanol extracts from A. lappa (68.1 mg $100\;g^{-1}$) and followed by Y. sonchifolia (11.2 mg $100\;g^{-1}$) Lycoris radiate extracts (87.2%) had the highest nitrite scavenging activity and followed by A. lappa (81.5%) and Y. sonchifolia (77.5%). Methanol extracts of A. lappa at 25 mg $100\;g^{-1}$ exhibited the highest DPPH radical scavenging activity by 90.8%, even though less activity than synthetic antioxidants Vitamin C or butylated hydroxytoluene (BHT). Level of polyphenols was highly correlated with anti oxidative activity ($r^2$ = 0.85). The results suggest that several medicinal plants selected had the potent biological activities, and that their activities were differential depending on plant species.

• Korean Journal of Plant Resources
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• v.26 no.1
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• pp.60-67
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• 2013

A laboratory experiment was conducted to determine the content of phenolics and flavonoids, antioxidant activity and antioxidant enzyme activity for the extracts from cowpea seed and sprouts. Plant length and weight of cowpea sprouts were significantly increased until 7 days after seeding. Total phenolics level [mg chlorogenic acid equivalents (CAE) $kg^{-1}$ DW] was highest in dry seed (DS) extracts of cowpea ($63.9mg\;kg^{-1}$), followed by imbibed seed (IS) ($56.8mg\;kg^{-1}$) and 1-day-old sprout (1DOS) extracts ($46.4mg\;kg^{-1}$), and significantly reduced with increase of sprout age (p < 0.05). The antioxidant activity of the methanol extracts from all the samples showed same tendency to the results of total phenolics level, and dose-dependently increased. DPPH (1,1-diphenyl-2-picryl hydrazyl radical) free radical scavenging activity was higher in DS (87.3%) and IS (41.2%) than in cowpea sprouts from 1DOS to 7DOS, ranging from 17.1 to 30.4%. Antioxidant enzymes, APX, POX, and POX activities were highest in 7DOS and lowest in DS. SOD activity showed much higher activity in sprouts and in seeds. Correlation coefficient between physiological-active substance and the activity was highest between APX and CAT activities ($r^2$= 0.9574). Especially, total phenolics content was more highly correlated with antioxidant or with antioxidant enzyme activities than was total flavonoid level.

• Preventive Nutrition and Food Science
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• v.9 no.4
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• pp.289-294
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• 2004

The antioxidant activity of forty two kinds of salad vegetables grown in Korea was evaluated. Methanol extract of freeze-dried vegetable was assayed by radical scavenging activity using 1,2-diphenyl-2-picrylhydrazyl (DPPH) and Fe^{2+}$-catalyzed lipid peroxidation inhibition by TBA method. Total phenolics were determined colorimetrically using Folin-Ciocalteu reagent. The highest radical scavenging activity was expressed by perilla leaf, followed by dandelion leaf, red and green leafy lettuce, of which $IC_{50}$ was less than 0.10 mg/mL. Angelica leaf showed the highest inhibitory action for lipid peroxidation with $95\%$, and then dandelion leaf, water spinach, and perilla leaf inhibited over $80\%$. However, lettuce (Iceberg) and young Chinese cabbage exhibited the lowest antioxidant activity based on both assay methods. Highly positive correlations between antioxidative activities and total phenolics were observed (p < 0.001). The results suggested that salad vegetables, especially perilla leaf, leafy lettuce, dandelion or angelica, could be used for easily accessible sources of natural antioxidants.

• Food Science and Biotechnology
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• v.18 no.1
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• pp.108-112
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• 2009

Antioxidant and anticancer effects of methanolic extracts from the flesh (WFME) and peel (WPME) of white onion, the flesh (YFME) and peel (YPME) of yellow onion, the flesh (RFME) and peel (RPME) of red onion were studied. The content of total phenolics in WFME, WPME, YPME, YFME, RPME, and RFME were $0.260{\pm}0.01$, $4.480{\pm}0.23$, $0.319{\pm}0.02$, $719.12{\pm}37.36$, $0.248{\pm}0.01$, and $806.21{\pm}26.38\;mg/g$, respectively. The quercetin content of WFME, WPME, YFME, YPME, RFME, and RPME were $12.56{\pm}0.19$, $3.57{\pm}0.14$, $15.24{\pm}0.65$, $755.29{\pm}22.24$, $5.70{\pm}0.23$, and $774.03{\pm}29.48\;mg$/100 g, respectively. Like total phenolics, the highest 2,2'-diphenyl-1-picrylhydrazyl (DPPH) scavenging activities were found in RPME. However, inhibitory effects on lipid oxidation of RPME were similar to those of WPME and YPME. In addition, inhibitory effect of WPME, YPME, and RPME for human breast cancer cell (MCF-7) growth were 78.43, 81.90, and 96.52% while those on human prostate cancer cell (LNcap) were 71.58, 77.93, and 98.47% at $100{\mu}g/mL$, respectively. Total phenolics, quercetin content, antioxidant, and anticancer activities exhibited significant variation among the 3 onion varieties in this experiment. Therefore, it is assumed that antioxidant and anticancer activities were affected by the total phenolics and quercetin level of onion.

• Korean Journal of Plant Resources
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• v.26 no.2
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• pp.159-168
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• 2013

The study was conducted to determine the content of phenolics and flavonoids, antioxidant activity and antioxidant enzyme activity for the extract from 7 days old sprouts of cowpea (cv. "Seowon"), mungbean (cv. "Owool") and soybean (cv. "Pungsannamulkong"). Sprout length and weight of soybean sprouts were higher than those of cowpea and mungbean sprouts. Total phenolics content [mg ferulic acid equivalents (FAE) $kg^{-1}$ DW] was highest in soybean sprout extracts (82.2 mg $kg^{-1}$), followed by cowpea (32.2 mg $kg^{-1}$) and mungbean (24.5 mg $kg^{-1}$) sprout extracts (p < 0.05). The result of total flavonoid level [mg rutin equivalents $kg^{-1}$ DW] had same tendency to the total phenolics, showing lower amounts. The antioxidant activity of the methanol extracts from all the plant dose-dependently increased. DPPH (1,1-diphenyl-2-picryl hydrazyl radical) free radical scavenging activity was higher in cowpea (44%) and mungbean (42%) sprouts than in soybean sprouts (25%). Among antioxidant enzymes, APX and POX activities were highest in cowpea sprouts and CAT and SOD activities in soybean sprouts. The results showed that total phenolics content ($r^2$ = 0.5320 ~ 0.9032) and total flavonoids level ($r^2$ = 0.4672 ~ 0.9380) were highly correlated with antioxidant or with antioxidant enzyme activity, and that the level and activity of biologically active substances were different depending on plant species.

• Horticultural Science & Technology
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• v.35 no.1
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• pp.88-97
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• 2017

This study explored the physicochemical and nutritional changes associated with storage duration of fresh tomatoes. Fruits of the 'TY Megaton' and 'Yureka' tomato cultivars were harvested at the pink stage and stored at $12^{\circ}C$ for 20 days. During storage, firmness, weight loss, skin color (Hunter L, a, b, a / b values), soluble solids content (SSC), titratable acidity (TA), pH, antioxidant contents (lycopene, ascorbic acid, and total phenolics) and antioxidant activity were evaluated. Firmness was above the minimum marketable limit and fresh weight loss was below maximum acceptable weight loss after 3 weeks of storage, and no deleterious effect on antioxidant contents or activities were observed. Significant differences in SSC, TA, and pH were seen between varieties, but not between fruits stored for different durations. In both varieties, Hunter a values increased more than five-fold after 8 days of storage; this correlated with a more than four-fold accumulation of lycopene after two weeks of storage. The antioxidant activity of tomatoes was highest at the beginning of the storage period, likely because of the effective DPPH - reducing power of ascorbic acid and total phenolics. Antioxidant activity increased after 12 days of storage because of increasing lycopene content. Hence, this study indicates that pink - stage tomatoes may be stored at $12^{\circ}C$ for up to 3 weeks without affecting marketability or nutritional value.

• Korean Journal of Food Science and Technology
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• v.53 no.3
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• pp.329-333
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• 2021

Subcritical water extraction (SWE) is an eco-friendly extraction method that uses only purified water as a solvent under high temperature and high pressure conditions. In this study, total phenolics, and antioxidant activity were evaluated in Ziziphus jujuba Mill extracts from subcritical water obtained by varying the extraction temperature (110-190℃) and extraction time (1-20 min). Total phenolics was maximized with extraction at 190℃ for 15 min (67.79±3.45 mg gallic acid equivalent/g jujube). The 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity (48.84±4.74%) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) free radical scavenging activity (84.75±1.15%) were maximal at extraction conditions of 190℃, for 20 min. All jujube extracts prepared using SWE had higher total phenolics and antioxidant activities than extracts prepared using organic solvent extraction (60℃, 120 min), including methanol and ethanol. SWE could be an excellent alternative to organic solvents for extracting phenolics and antioxidant compounds.

• Journal of Nutrition and Health
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• v.31 no.8
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• pp.1355-1364
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• 1998

This study was planned to investigate the effect of 40 plant ethanolic extracts on antioxidant activities in vitro. The total phenolics, $\beta$-carotene, $\alpha$-tocopherol and selenium contents were also determined . Antioxidant activities fo the ethanolic extracts(0.02%, w/w) in the soybean oil were measured both by determining the peroxide value (POV) during 35 days of storage at 4$0^{\circ}C$ in a forced draft air-incubator and by determining changes in conductivity at 11$0^{\circ}C$(Rancimat method.). Soybean oil without any additives was used as a control and that treated with 0.02% BHT was used as a positive control. Based on the POV determination, green tea extract was found to be the most effective in stabilizing soybean oil, then followed by long tea, which both of them showed higher antioxidant activities compared to the BHT treatment. The antioxidant activities of them showed higher antioxidant activities compared to the BHT treatment. the antioxidant activities of coffee, cinnamomi cortex, acanthopanacis cortex, black tea, orange peel , instant coffee, peony and crni fructus extracts were stronger compared to the control .By the Rancimat method, green tea leaf and oolong tea leaf, foxglove, acanthopanacis cortex and peony extracts. Compared to other extracts, green tea leaf, black tea leaf, foxglove, acanthopanacis cortex and peony extracts had stronger antioxidative effects in both the POV and Rancimat methods used in this study. ethanolic extracts which showed the stronger antioxidative effect also has the higher contents of total phenolics, $\beta$-carotene, and/or $\alpha$-tocopherol. The antioxidative effect of ethanolic extracts was found to be due to the combined effect of various antioxidants.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.12
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• pp.1725-1730
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• 2010

To obtain basic information on the potential use of propolis as a raw material in functional food, proximate composition, total phenolics content and antioxidant activities of different propolis extracts in Korea were investigated. Propolis had the highest level of crude fat and the lowest level of crude fiber. The total phenolics content of ethanol and water extract of propolis from Geochang (GEE and GWE), ethanol and water extract of propolis from Jeju (JEE and JWE) were 184.17, 316.19, 204.33 and 47.83 mg gallic acid equivalent/g, respectively. GWE contained relatively higher levels of total phenolics than the other extracts. The antioxidant potential of the extracts was assessed by different in vitro assays such as DPPH, ABTS, reducing power, ferric reducing/antioxidant power (FRAP) and peroxidation inhibiting activities through linoleic acid emulsion system. DPPH and ABTS radical scavenging activities of all the extracts were dose dependent. The GWE exhibited the best performance in reducing power, FRAP, and lipid peroxidation using ferric thiocyanate (FTC) assay. These results demonstrated that GWE has excellent antioxidant activities and thus it has great potential as a raw material for functional food.

• The Korean Journal of Food And Nutrition
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• v.34 no.6
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• pp.662-668
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• 2021

Aster koraiensis Nakai (A. koraiensis) which has been used as a food and medicinal plant in the past, is valuable as functional food material. Therefore, the aim of this study was to determine the antioxidant properties and major phenolics of A. koraiensis extracts with different ethanol concentrations (0, 50, 70, and 100% aqueous ethanol solution). When ethanol concentration in the extraction solvent was increased, extraction yield decreased; 34.2, 23.2, 21.0, and 5.5% in 0, 50, 70, and 100% ethanolic extracts, respectively. Total phenolics content and antioxidant activities of extracts were increased in an ethanol concentration-dependant manner. The major phenolics in the extracts were chlorogenic acid (21.264~58.666 mg/g), isochlorogenic acid A (10.432~145.353 mg/g), and isochlorogenic acid C(0.239~13.148 mg/g), and these phenolic contents were higher in 70 and 100% ethanolic extracts than other extracts. Significant correlations were observed between ethanol concentration of extraction solvent, antioxidant properties, and major phenolics. These results indicated that the optimal ethanol concentration for extraction was 70%.