• Korean Journal of Plant Resources
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• v.19 no.6
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• pp.670-676
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• 2006

Tea polysaccharide had high antioxidant activity and it could be used to cure diabetes. Antioxidant activity of tea poly-saccharide (TPS) from three kinds of tea (green tea, oolong tea and black tea) were compared, the result indicated that oolong tea polysaccharide (OTPS) had the highest antioxidant activity. In order to explicate the mechanism of antioxidant and hypoglycemic activity, the streptozotocin (STZ)-induced diabetes mice model (DM) was established. The influence of OTPS on blood-glucose, content of MDA and NO, and activities of GSH-PX, SOD, NOS in serum, kidney and liver were investigated. The result showed that after four weeks injection of OTPS to DM mice, the blood-glucose of three treatment group reduced by 14.5%,21.5% and 33.3%, respectively, comparing to the model control. The reduction effect of OTPS increased with the rise of dose. The activity of SOD and GSH-PX elevated significantly, while the activity of NOS decreased. The content of MDA and NO reduced significantly. The above results imply that antioxidant activity was enhanced. Comparing to XKW treatment, the effect of a dose of 300mg/(kg. bw) OTPS was much better. The research showed that the OTPS had a significant effect on reducing blood glucose, and could enhance the antioxidant activity of DM mice.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1299-1304
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• 2008

The potential antioxidant activities of different fractions from a 70% methanolic (MeOH) extract of Sonchus oleraceus were assayed in vitro. All of the fractions exception of n-hexane showed a strong antioxidant activity, especially the ethyl acetate (EtOAc) fraction, which showed the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity ($IC_{50}=19.25{\mu}g/mL$). The results of hydroxyl radical scavenging activity and a reducing power assay showed concentration dependence, the EtOAc fraction demonstrating a better result than the other fractions at the same concentration in the studies. Additionally, the fractions' total phenolic (TP) contents was measured, phenolic compounds such as tannic acid, p-coumatric acid, quercetin, epicathchin, and kaempferol being detected by high performance liquid chromatography (HPLC). Meanwhile, a regression analysis revealed a moderate-to-high correlation coefficient between the antiradical activity and the TP contents, suggesting that fractions obtained from the 70% MeOH extract of S. oleraceus are of potential use as sources of antioxidant material.

• Journal of Applied Biological Chemistry
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• v.51 no.3
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• pp.111-116
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• 2008

Aralia elata seeds were successively extracted with water, methanol, ethanol, acetone and chloroform. The crude extracts were investigated for antioxidant and antidiabetic activities. The antioxidant properties of various extracts were evaluated by antioxidant tests, such as DPPH free radical-scavenging activity, hydroxyl radical-scavenging assay, metal-chelating activity, lipid peroxidation inhibition activity and reducing power assay. The 70% methanol extract exhibited the highest activity in the in vitro models of DPPH free radical-scavenging activity, metal-chelating activity, and reducing power assay. Acetone extract showed good effects on lipid peroxidation inhibition and hydroxyl radical-scavenging assay at a low concentration. In addition, the $\alpha$-glucosidase inhibition assay showed that 70% methanol extract had the highest activity. These results indicate the high possibility of using A. elata seeds for medical application due to their efficient antioxidant properties.

• Preventive Nutrition and Food Science
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• v.19 no.1
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• pp.19-26
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• 2014

Increased consumption of fresh vegetables that are high in polyphenols has been associated with a reduced risk of oxidative stress-induced disease. The present study aimed to evaluate the antioxidant effects of spinach in vitro and in vivo in hyperlipidemic rats. For measurement of in vitro antioxidant activity, spinach was subjected to hot water extraction (WE) or ethanol extraction (EE) and examined for total polyphenol content (TPC), oxygen radical absorbance capacity (ORAC), cellular antioxidant activity (CAA), and antigenotoxic activity. The in vivo antioxidant activity of spinach was assessed using blood and liver lipid profiles and antioxidant status in rats fed a high fat-cholesterol diet (HFCD) for 6 weeks. The TPC of WE and EE were shown as $1.5{\pm}0.0$ and $0.5{\pm}0.0mg$ GAE/g, respectively. Increasing the concentration of the extracts resulted in increased ORAC value, CAA, and antigenotoxic activity for all extracts tested. HFCD-fed rats displayed hyperlipidemia and increased oxidative stress, as indicated by a significant rise in blood and liver lipid profiles, an increase in plasma conjugated diene concentration, an increase in liver thiobarbituric acid reactive substances (TBARS) level, and a significant decrease in manganese superoxide dismutase (Mn-SOD) activity compared with rats fed normal diet. However, administration of 5% spinach showed a beneficial effect in HFCD rats, as indicated by decreased liver TBARS level and DNA damage in leukocyte and increased plasma conjugated dienes and Mn-SOD activity. Thus, the antioxidant activity of spinach may be an effective way to ameliorate high fat and cholesterol diet-induced oxidative stress.

• KSBB Journal
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• v.29 no.2
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• pp.92-97
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• 2014

In this study, we investigate the antimicrobial and antioxidant activities of extracts of Enteromorpha intestinalis. To evaluate the antimicrobial and antioxidant activities, three solvents (hexane, chloroform and methanol) were applied to obtain extracts. The extraction yields are hexane (A) 1.11%, chloroform (B) 0.94%, and methanol (C) 8.2%. Also, the contents of total phenolic compounds of extract A, B, C are 4.03%, 8.15%, and 2.33%, respectively. In the results of antimicrobial activity, extract A and B have higher activity than that of extract C. Especially, Vibrio vulificus, Pseudomonas aeruginosa, Bacillus subtilis, Escherichia coli are more sensitive than others. In antioxidant activity, extract A and B present the higher DPPH activity than that of control (BHA and ascorbic acid). The DPPH radical scavenging activity and SOD-like activity are ordered as B>C>A. However, extract C show high value in ferric reducing antioxidant power assay. In nitrite scavenging activity, extract A is relatively higher than others. However, the antioxidant activities are lower than that of controls (ascorbic acid and BHA). The antioxidant activities are presented the increasing pattern of increasing by the increasing of extract concentration.

• Journal of The Korean Society of Grassland and Forage Science
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• v.32 no.4
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• pp.361-368
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• 2012

The present study was conducted to develop persimmon peel, a by-product of dried persimmon manufacturing, as a feed additive via lactic acid bacteria fermentation. Pediococcus pentosaceus, Lactobacillus plantarum, and three strains of Leuconostoc mesenteroides were used as a starter culture in the solid state fermentation of persimmon peel, and antioxidant activity and total polyphenol content were assessed. Leuconostoc mesenteroides KCTC 3100 showed high antioxidant activity (p<0.05), whereas Pediococcus pentosaceus showed high total polyphenol content (p<0.05). These two strains were thus selected as starter culture strains. Glucose, sucrose and molasses were used as variables for optimization and a total 15 experimental runs were produced according to Box-Behnken design. Regarding significant effects of variables, molasses showed linear and square effects on antioxidant activity of persimmon peel fermentation (p<0.05). In conclusion, optimum concentrations of glucose, sucrose, and molasses were determined to be 4.2, 3.9 and 5.3 g/L, respectively, using a response surface model. Antioxidant activity was also improved 2.5 fold after optimization.

• Korean Journal of Medicinal Crop Science
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• v.10 no.4
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• pp.288-293
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• 2002

Allergen-removed-extract was produced from Rush verniciflua by two phase methods. Phase one was high temperature treatment of Rush verniciflua tree to get allergen-removed-extract. Phase two was extraction of solution from phase one product using water or organic solvents. The solutions from above method show high antioxidant activity, anticancer activity, and improvement in lung function, but did not contain urushiol family compounds.

• Korean Journal of Pharmacognosy
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• v.25 no.3
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• pp.226-232
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• 1994

An antioxidant activity of Gardenia Fruit (Gardenia jasminoides Ellis) which has been used for food coloring was studied. The antioxidant activity was determined by measuring lipid peroxide produced when a mouse liver homogenate was exposed to the air at $37^{\circ}C$, using 2-thiobarbituric acid (TBA). Both water and methanol extracts of Gardenia Fruit showed the antioxidant activity. On solvent fractionation, the antioxidant activity was removed into the ethyl acetate and butanol soluble fractions. And the final water soluble fraction also showed the antioxidant activity in the low concentration, but it promoted the lipid peroxidation in the high concentration. Two compounds (I and II) having the antioxidant activity were isolated from the butanol fraction, and compound I also occurred in the ethyl acetate fraction. The antioxidant activity of compound II was more potent than that of I. By analyzing data for UV, IR and $^1H-NMR$, compounds I and II were identified as geniposide and crocin, respectively.

• Natural Product Sciences
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• v.25 no.1
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• pp.44-48
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• 2019

Nelumbo nucifera Gaertn. (Nymphaeaceae) is commonly called lotus and its leaves are widely been used as functional ingredients due to its antioxidant activity. For maximum efficacy, optimized extraction condition was established using response surface methodology. The high F-values, low p-values and insignificant p-value for lack-of-fit supported the fitness of the model and yielded the second-order polynomial regression for the antioxidant activity. The optimized extract was obtained by the extraction of 1 g of lotus leaves with 40 mL of 50% MeOH at $10.0^{\circ}C$, which exerted 70.1% antioxidant activity. Close correlation between phenolic content and antioxidant activity suggested phenolic compounds as active constituents of lotus leaves. In addition, comparison of different parts of lotus demonstrated the most potent antioxidant activity of flowers, followed by leaves and roots. Taken together, these results provide useful information about lotus leaves for the development as antioxidant ingredients. In addition, flowers and roots as well as leaves are suggested as good sources for antioxidant activity.

• Natural Product Sciences
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• v.29 no.1
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• pp.1-9
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• 2023

This study assessed in vitro antioxidant activity (ABTS⁺ and DPPH) of Vitex rotundifolia seeds collected from two different regions in Korea (Jungjang City and Sindu City). Three extraction methods using ethanol, methanol, and water were prepared separately and subjected to quantification by reverse-phase high-performance liquid chromatography-photodiode array (HPLC-PDA) analysis as well as antioxidant testing. Among them, the water-based extract exhibited superior activity in the ABTS⁺ compared with the ethanol- and methanol-based extracts, while the DPPH assay analysis, revealed that the methanol-based extract had very low antioxidant activity. The concentrations of vanillic acid (1), luteolin (2), vitexicarpin (3), and artemetin (4) were quantified using HPLC-PDA analysis. Vanillic acid (1) was identified as the main antioxidant in V. rotundifolia seeds. Combining the antioxidant activity and quantitative analysis results, the water-based extract was considered to have the highest antioxidant activity. Furthermore, vanillic acid (1) was detected in the leaves and stems of V. rotundifolia plants from different regions, indicating that this species has the potential for use in future antioxidant-applications.